Endothelin-A receptor blockade slows the progression of renal injury in experimental renovascular disease.

PubMed

Kelsen, Silvia; Hall, John E; Chade, Alejandro R

2011-07-01

Endothelin (ET)-1, a potent renal vasoconstrictor with mitogenic properties, is upregulated by ischemia and has been shown to induce renal injury via the ET-A receptor. The potential role of ET-A blockade in chronic renovascular disease (RVD) has not, to our knowledge, been previously reported. We hypothesized that chronic ET-A receptor blockade would preserve renal hemodynamics and slow the progression of injury of the stenotic kidney in experimental RVD. Renal artery stenosis, a major cause of chronic RVD, was induced in 14 pigs and observed for 6 wk. In half of the pigs, chronic ET-A blockade was initiated (RVD+ET-A, 0.75 mg·kg(-1)·day(-1)) at the onset of RVD. Single-kidney renal blood flow, glomerular filtration rate, and perfusion were quantified in vivo after 6 wk using multidetector computer tomography. Renal microvascular density was quantified ex vivo using three-dimensional microcomputer tomography, and growth factors, inflammation, apoptosis, and fibrosis were determined in renal tissue. The degree of stenosis and increase in blood pressure were similar in RVD and RVD+ET-A pigs. Renal hemodynamics, function, and microvascular density were decreased in the stenotic kidney but preserved by ET-A blockade, accompanied by increased renal expression of vascular endothelial growth factor, hepatocyte growth factor, and downstream mediators such as phosphorilated-Akt, angiopoietins, and endothelial nitric oxide synthase. ET-A blockade also reduced renal apoptosis, inflammation, and glomerulosclerosis. This study shows that ET-A blockade slows the progression of renal injury in experimental RVD and preserves renal hemodynamics, function, and microvascular density in the stenotic kidney. These results support a role for ET-1/ET-A as a potential therapeutic target in chronic RVD.

Endothelin-A receptor blockade slows the progression of renal injury in experimental renovascular disease

PubMed Central

Kelsen, Silvia; Hall, John E.

2011-01-01

Endothelin (ET)-1, a potent renal vasoconstrictor with mitogenic properties, is upregulated by ischemia and has been shown to induce renal injury via the ET-A receptor. The potential role of ET-A blockade in chronic renovascular disease (RVD) has not, to our knowledge, been previously reported. We hypothesized that chronic ET-A receptor blockade would preserve renal hemodynamics and slow the progression of injury of the stenotic kidney in experimental RVD. Renal artery stenosis, a major cause of chronic RVD, was induced in 14 pigs and observed for 6 wk. In half of the pigs, chronic ET-A blockade was initiated (RVD+ET-A, 0.75 mg·kg−1·day−1) at the onset of RVD. Single-kidney renal blood flow, glomerular filtration rate, and perfusion were quantified in vivo after 6 wk using multidetector computer tomography. Renal microvascular density was quantified ex vivo using three-dimensional microcomputer tomography, and growth factors, inflammation, apoptosis, and fibrosis were determined in renal tissue. The degree of stenosis and increase in blood pressure were similar in RVD and RVD+ET-A pigs. Renal hemodynamics, function, and microvascular density were decreased in the stenotic kidney but preserved by ET-A blockade, accompanied by increased renal expression of vascular endothelial growth factor, hepatocyte growth factor, and downstream mediators such as phosphorilated-Akt, angiopoietins, and endothelial nitric oxide synthase. ET-A blockade also reduced renal apoptosis, inflammation, and glomerulosclerosis. This study shows that ET-A blockade slows the progression of renal injury in experimental RVD and preserves renal hemodynamics, function, and microvascular density in the stenotic kidney. These results support a role for ET-1/ET-A as a potential therapeutic target in chronic RVD. PMID:21478482

Metabolic and hemodynamic effects of sodium-dependent glucose cotransporter 2 inhibitors on cardio-renal protection in the treatment of patients with type 2 diabetes mellitus.

PubMed

Kashiwagi, Atsunori; Maegawa, Hiroshi

2017-07-01

The specific sodium-glucose cotransporter 2 inhibitors (SGLT2 inhibitors) inhibit glucose reabsorption in proximal renal tubular cells, and both fasting and postprandial glucose significantly decrease because of urinary glucose loss. As a result, pancreatic β-cell function and peripheral insulin action significantly improve with relief from glucose toxicity. Furthermore, whole-body energy metabolism changes to relative glucose deficiency and triggers increased lipolysis in fat cells, and fatty acid oxidation and then ketone body production in the liver during treatment with SGLT2 inhibitors. In addition, SGLT2 inhibitors have profound hemodynamic effects including diuresis, dehydration, weight loss and lowering blood pressure. The most recent findings on SGLT2 inhibitors come from results of the Empagliflozin, Cardiovascular Outcomes and Mortality in Type 2 Diabetes trial. SGLT2 inhibitors exert extremely unique and cardio-renal protection through metabolic and hemodynamic effects, with long-term durability on the reduction of blood glucose, bodyweight and blood pressure. Although a site of action of SGLT2 inhibitors is highly specific to inhibit renal glucose reabsorption, whole-body energy metabolism, and hemodynamic and renal functions are profoundly modulated during the treatment of SGLT2 inhibitors. Previous studies suggest multifactorial clinical benefits and safety concerns of SGLT2 inhibitors. Although ambivalent clinical results of this drug are still under active discussion, the present review summarizes promising recent evidence on the cardio-renal and metabolic benefits of SGLT2 inhibitors in the treatment of type 2 diabetes. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

Atherosclerotic renal artery stenosis in the post-CORAL era part 1: the renal penumbra concept and next-generation functional diagnostic imaging.

PubMed

Sag, Alan Alper; Inal, Ibrahim; Okcuoglu, John; Rossignol, Patrick; Ortiz, Alberto; Afsar, Baris; Sos, Thomas A; Kanbay, Mehmet

2016-04-01

After three neutral trials in which renal artery stenting failed to improve renal function or reduce cardiovascular and renal events, the controversy surrounding diagnosis and treatment of atherosclerotic renal artery stenosis and renovascular hypertension has led to paradigm shifts in the diagnostic algorithm. Noninvasive determination of earlier events (cortex hypoxia and renal artery hemodynamic changes) will supersede late sequelae (calcific stenosis, renal cortical thinning). Therefore, this review proposes the concept of renal penumbra in defining at-risk ischemic renal parenchyma. The complex field of functional renal magnetic resonance imaging will be reviewed succinctly in a clinician-directed fashion. Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

[Clinical and experimental study of the production of renal hemodynamic effects of IABP-assisted pulsatile flow extracorporeal circulation].

PubMed

Moro, H

1992-01-01

Renal hemodynamics during IABP-assisted pulsatile flow extracorporeal circulation was assessed in terms of measurement values for intraoperative renal blood flow obtained by the local thermodilution method in human clinical patients. In addition, the effect of IABP on renal hemodynamics was investigated in an animal model of renal denervation in a study undertaken to elucidate the action mechanism of IABP. Eighteen patients with acquired heart disease were involved in the study and measured for the renal blood flow (RBF), cardiac output (CO), renal-systemic partition coefficient for blood flow (RBF/CO), renal vascular resistance (RVR) and perfusion pressure. In the pulsatile flow group, the RBF/CO increased as the number of pump runs increased, whole the RVR was conversely reduced with increasing pump runs. The experimental study without extracorporeal circulation was conducted on 19 mongrel dogs. During IABP runs RBF/CO increased, while the RVR decreased. After renal denervation, no noticeable influence of IABP upon renal hemodynamics was observed. Following a loading dose of noradrenaline (Norad), the RVR increased in a Norad concentration-dependent fashion, independently of IABP and renal denervation. These results indicate that IABP reduces the RVR and thereby exerts a favorable action on renal hemodynamics during pump times. The study thus warrants us to surmise that a mechanism involving the renal sympathetic nerves might play an important role in the production of favorable renal hemodynamic effects of IABP-assisted pulsatile flow extracorporeal circulation.

The macro- and microcirculation of the kidney.

PubMed

Guerci, Philippe; Ergin, Bulent; Ince, Can

2017-09-01

Acute kidney injury (AKI) remains one of the main causes of morbidity and mortality in the intensive care medicine today. Its pathophysiology and progress to chronic kidney disease is still under investigation. In addition, the lack of techniques to adequately monitor renal function and microcirculation at the bedside makes its therapeutic resolution challenging. In this article, we review current concepts related to renal hemodynamics compromise as being the event underlying AKI. In doing so, we discuss the physiology of the renal circulation and the effects of alterations in systemic hemodynamics that lead to renal injury specifically in the context of reperfusion injury and sepsis. The ultimate key culprit of AKI leading to failure is the dysfunction of the renal microcirculation. The cellular and subcellular components of the renal microcirculation are discussed and how their injury contributes to AKI is described. Copyright © 2017. Published by Elsevier Ltd.

Renal Hemodynamics in AKI: In Search of New Treatment Targets

PubMed Central

Matejovic, Martin; Ince, Can; Chawla, Lakhmir S.; Blantz, Roland; Molitoris, Bruce A.; Okusa, Mark D.; Kellum, John A.; Ronco, Claudio

2016-01-01

Novel therapeutic interventions are required to prevent or treat AKI. To expedite progress in this regard, a consensus conference held by the Acute Dialysis Quality Initiative was convened in April of 2014 to develop recommendations for research priorities and future directions. Here, we highlight the concepts related to renal hemodynamics in AKI that are likely to reveal new treatment targets on investigation. Overall, we must better understand the interactions between systemic, total renal, and glomerular hemodynamics, including the role of tubuloglomerular feedback. Furthermore, the net consequences of therapeutic maneuvers aimed at restoring glomerular filtration need to be examined in relation to the nature, magnitude, and duration of the insult. Additionally, microvascular blood flow heterogeneity in AKI is now recognized as a common occurrence; timely interventions to preserve the renal microcirculatory flow may interrupt the downward spiral of injury toward progressive kidney failure and should, therefore, be investigated. Finally, development of techniques that permit an integrative physiologic approach, including direct visualization of renal microvasculature and measurement of oxygen kinetics and mitochondrial function in intact tissue in all nephron segments, may provide new insights into how the kidney responds to various injurious stimuli and allow evaluation of new therapeutic strategies. PMID:26510884

Diabetes-Induced Reactive Oxygen Species: Mechanism of Their Generation and Role in Renal Injury

PubMed Central

Fakhruddin, Selim; Alanazi, Wael

2017-01-01

Diabetes induces the onset and progression of renal injury through causing hemodynamic dysregulation along with abnormal morphological and functional nephron changes. The most important event that precedes renal injury is an increase in permeability of plasma proteins such as albumin through a damaged glomerular filtration barrier resulting in excessive urinary albumin excretion (UAE). Moreover, once enhanced UAE begins, it may advance renal injury from progression of abnormal renal hemodynamics, increased glomerular basement membrane (GBM) thickness, mesangial expansion, extracellular matrix accumulation, and glomerulosclerosis to eventual end-stage renal damage. Interestingly, all these pathological changes are predominantly driven by diabetes-induced reactive oxygen species (ROS) and abnormal downstream signaling molecules. In diabetic kidney, NADPH oxidase (enzymatic) and mitochondrial electron transport chain (nonenzymatic) are the prominent sources of ROS, which are believed to cause the onset of albuminuria followed by progression to renal damage through podocyte depletion. Chronic hyperglycemia and consequent ROS production can trigger abnormal signaling pathways involving diverse signaling mediators such as transcription factors, inflammatory cytokines, chemokines, and vasoactive substances. Persistently, increased expression and activation of these signaling molecules contribute to the irreversible functional and structural changes in the kidney resulting in critically decreased glomerular filtration rate leading to eventual renal failure. PMID:28164134

Renal Blood Flow, Glomerular Filtration Rate, and Renal Oxygenation in Early Clinical Septic Shock.

PubMed

Skytte Larsson, Jenny; Krumbholz, Vitus; Enskog, Anders; Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2018-06-01

Data on renal hemodynamics, function, and oxygenation in early clinical septic shock are lacking. We therefore measured renal blood flow, glomerular filtration rate, renal oxygen consumption, and oxygenation in patients with early septic shock. Prospective comparative study. General and cardiothoracic ICUs. Patients with norepinephrine-dependent early septic shock (n = 8) were studied within 24 hours after arrival in the ICU and compared with postcardiac surgery patients without acute kidney injury (comparator group, n = 58). None. Data on systemic hemodynamics and renal variables were obtained during two 30-minute periods. Renal blood flow was measured by the infusion clearance of para-aminohippuric acid, corrected for renal extraction of para-aminohippuric acid. Renal filtration fraction was measured by renal extraction of chromium-51 labeled EDTA. Renal oxygenation was estimated from renal oxygen extraction. Renal oxygen delivery (-24%; p = 0.037) and the renal blood flow-to-cardiac index ratio (-21%; p = 0.018) were lower, renal vascular resistance was higher (26%; p = 0.027), whereas renal blood flow tended to be lower (-19%; p = 0.068) in the septic group. Glomerular filtration rate (-32%; p = 0.006) and renal sodium reabsorption (-29%; p = 0.014) were both lower in the septic group. Neither renal filtration fraction nor renal oxygen consumption differed significantly between groups. Renal oxygen extraction was significantly higher in the septic group (28%; p = 0.022). In the septic group, markers of tubular injury were elevated. In early clinical septic shock, renal function was lower, which was accompanied by renal vasoconstriction, a lower renal oxygen delivery, impaired renal oxygenation, and tubular sodium reabsorption at a high oxygen cost compared with controls.

Arterial stiffness, body fat compartments, central hemodynamics, renal function and left atrial size.

PubMed

Katulska, Katarzyna; Milewska, Agata; Wykretowicz, Mateusz; Krauze, Tomasz; Przymuszala, Dagmara; Piskorski, Jaroslaw; Stajgis, Marek; Guzik, Przemyslaw; Wysocki, Henryk; Wykrętowicz, Andrzej

2013-10-01

Left atrial (LA) size is an important predictor of stroke, death, and atrial fibrillation. It was demonstrated recently that body fat, arterial stiffness and renal functions are associated with LA diameter. However, data are lacking for comprehensive assessments of all these risk factors in a single population. Therefore, the aim of the present study was to investigate the association between LA size and different fat descriptors, central hemodynamics, arterial stiffness, and renal function in healthy subjects. To this end, body fat percentage, abdominal, subcutaneous fat, and general descriptors of body fat were estimated in 162 healthy subjects (mean age 51 years). Echocardiography was performed to assess LA diameter. Arterial stiffness and peripheral and central hemodynamics were estimated by digital volume pulse analysis and pulse wave analysis. Glomerular filtration rate was estimated by MDRD formula. There were significant (p < 0.05) bivariate correlations between LA diameter and all descriptors of body fat (except subcutaneous fat). Arterial stiffness and estimated glomerular filtration rate (eGFR) were also significantly correlated with LA size. Multiple regression analysis including all significant confounders, such as sex, mean arterial pressure, arterial stiffness, eGFR and body fat descriptors, explained 35% of variance in LA diameter. In conclusion, the present study reveals significant, independent relationships between body fat, arterial stiffness, and LA size.

Antibody and complement reduce renal hemodynamic function in isolated perfused rat kidney.

PubMed

Jocks, T; Zahner, G; Helmchen, U; Kneissler, U; Stahl, R A

1996-01-01

To evaluate the effect of antibody and complement on renal hemodynamic changes, glomerular injury was induced in isolated perfused kidneys by an anti-thymocyte antibody (ATS) and rat serum (RS). Glomerular filtration rate (GFR), renal vascular resistance (RVR), and renal perfusate flow (RPF) were assessed over an 80-min period. The possible role of thromboxane (Tx) was tested by the application of the Tx synthesis inhibitor UK-38485 and the Tx receptor blocker daltroban. Perfusion of kidneys with ATS and RS significantly reduced GFR at 10 min (control, 501 +/- 111; ATS + RS, 138 +/- 86 ml.g kidney-1.min-1, significance of F = 0.000) after RS. Similarly, RPF (ml.g kidney-1.min-1) fell from 19.2 +/- 1.8 to 6.1 +/- 2.0 (significance of F = 0.000), whereas RVR (mmHg.ml-1.g.min) increased threefold from 5.2 +/- 0.4 to 17.9 +/- 5.0 at 10 min. These changes were ameliorated by the pretreatment of the rats with daltroban and UK-38485. Addition of erythrocytes to the perfusate increased RVR and GFR, whereas RPF decreased compared with cell-free perfused kidneys. ATS and RS in this preparation also decrease GFR and RPF. The hemodynamic alterations appeared without changes in filtration fraction. Compared with untreated, perfused control kidneys, glomerular Tx formation was significantly increased in ATS and RS perfused kidneys. These data demonstrate that antibody and RS induce impairment of renal hemodynamics, which are mediated by increased Tx formation.

Improvement in Renal Hemodynamics following Combined Angiotensin II Infusion and AT1R Blockade in Aged Female Sheep following Fetal Unilateral Nephrectomy

PubMed Central

Singh, Reetu R.; Lankadeva, Yugeesh R.

2013-01-01

Renin-angiotensin system (RAS) is a powerful modulator of renal hemodynamic and fluid homeostasis. Up-regulation in components of intra-renal RAS occurs with ageing. Recently we reported that 2 year old uninephrectomised (uni-x) female sheep have low renin hypertension and reduced renal function. By 5 years of age, these uni-x sheep had augmented decrease in renal blood flow (RBF) compared to sham. We hypothesised that this decrease in RBF in 5 year old uni-x sheep was due to an up-regulation in components of the intra-renal RAS. In this study, renal responses to angiotensin II (AngII) infusion and AngII type 1 receptor (AT1R) blockade were examined in the same 5 year old sheep. We also administered AngII in the presence of losartan to increase AngII bioavailability to the AT2R in order to understand AT2R contribution to renal function in this model. Uni-x animals had significantly lower renal cortical content of renin, AngII (∼40%) and Ang 1–7 (∼60%) and reduced cortical expression of AT1R gene than sham animals. In response to both AngII infusion and AT1R blockade via losartan, renal hemodynamic responses and tubular sodium excretion were significantly attenuated in uni-x animals compared to sham. However, AngII infusion in the presence of losartan caused ∼33% increase in RBF in uni-x sheep compared to ∼14% in sham (P<0.05). This was associated with a significant decrease in renal vascular resistance in the uni-x animals (22% vs 15%, P<0.05) without any changes in systemic blood pressure. The present study shows that majority of the intra-renal RAS components are suppressed in this model of low renin hypertension. However, increasing the availability of AngII to AT2R by AT1R blockade improved renal blood flow in uni-x sheep. This suggests that manipulation of the AT2R maybe a potential therapeutic target for treatment of renal dysfunction associated with a congenital nephron deficit. PMID:23840884

Effects of a human recombinant alkaline phosphatase on renal hemodynamics, oxygenation and inflammation in two models of acute kidney injury.

PubMed

Peters, Esther; Ergin, Bülent; Kandil, Asli; Gurel-Gurevin, Ebru; van Elsas, Andrea; Masereeuw, Rosalinde; Pickkers, Peter; Ince, Can

2016-12-15

Two small clinical trials indicated that administration of bovine intestinal alkaline phosphatase (AP) improves renal function in critically ill patients with sepsis-associated acute kidney injury (AKI), for which the mechanism of action is not completely understood. Here, we investigated the effects of a newly developed human recombinant AP (recAP) on renal oxygenation and hemodynamics and prevention of kidney damage and inflammation in two in vivo AKI models. To induce AKI, male Wistar rats (n=18) were subjected to renal ischemia (30min) and reperfusion (I/R), or sham-operated. In a second model, rats (n=18) received a 30min infusion of lipopolysaccharide (LPS; 2.5mg/kg), or saline, and fluid resuscitation. In both models, recAP (1000U/kg) was administered intravenously (15min before reperfusion, or 90min after LPS). Following recAP treatment, I/R-induced changes in renal blood flow, renal vascular resistance and oxygen delivery at early, and cortical microvascular oxygen tension at late reperfusion were no longer significantly affected. RecAP did not influence I/R-induced effects on mean arterial pressure. During endotoxemia, recAP treatment did not modulate the LPS-induced changes in systemic hemodynamics and renal oxygenation. In both models, recAP did exert a clear renal protective anti-inflammatory effect, demonstrated by attenuated immunostaining of inflammatory, tubular injury and pro-apoptosis markers. Whether this renal protective effect is sufficient to improve outcome of patients suffering from sepsis-associated AKI is being investigated in a large clinical trial. Copyright © 2016. Published by Elsevier Inc.

Renal Hemodynamics in AKI: In Search of New Treatment Targets.

PubMed

Matejovic, Martin; Ince, Can; Chawla, Lakhmir S; Blantz, Roland; Molitoris, Bruce A; Rosner, Mitchell H; Okusa, Mark D; Kellum, John A; Ronco, Claudio

2016-01-01

Novel therapeutic interventions are required to prevent or treat AKI. To expedite progress in this regard, a consensus conference held by the Acute Dialysis Quality Initiative was convened in April of 2014 to develop recommendations for research priorities and future directions. Here, we highlight the concepts related to renal hemodynamics in AKI that are likely to reveal new treatment targets on investigation. Overall, we must better understand the interactions between systemic, total renal, and glomerular hemodynamics, including the role of tubuloglomerular feedback. Furthermore, the net consequences of therapeutic maneuvers aimed at restoring glomerular filtration need to be examined in relation to the nature, magnitude, and duration of the insult. Additionally, microvascular blood flow heterogeneity in AKI is now recognized as a common occurrence; timely interventions to preserve the renal microcirculatory flow may interrupt the downward spiral of injury toward progressive kidney failure and should, therefore, be investigated. Finally, development of techniques that permit an integrative physiologic approach, including direct visualization of renal microvasculature and measurement of oxygen kinetics and mitochondrial function in intact tissue in all nephron segments, may provide new insights into how the kidney responds to various injurious stimuli and allow evaluation of new therapeutic strategies. Copyright © 2016 by the American Society of Nephrology.

Divergent Effects of Hypertonic Fluid Resuscitation on Renal Pathophysiological and Structural Parameters in Rat Model of Lower Body Ischemia/Reperfusion-Induced Sterile Inflammation.

PubMed

Ergin, Bulent; Zuurbier, Coert J; Kapucu, Aysegul; Ince, Can

2017-12-27

The pathogenesis of acute kidney injury (AKI) is characterized by the deterioration of tissue perfusion and oxygenation and enhanced inflammation. The purpose of this study was to investigate whether or not the hemodynamic and inflammatory effects of hypertonic saline (HS) protect the kidney by promoting renal microcirculatory oxygenation and possible deleterious effects of HS due to its high sodium content on renal functional and structural injury following ischemia/reperfusion. Mechanically ventilated and anesthetized rats were randomly divided into four groups (n = 6 per group): a sham-operated control group; a group subjected to renal ischemia for 45 min by supra-aortic occlusion followed by 2 h of reperfusion (I/R); and I/R group treated with a continuous i.v. infusion (5 mL/kg/h) of either % 0.9 NaCl (IR+NS) or %10 NaCl (I/R+HS) after releasing the clamp. Systemic and renal hemodynamic, renal cortical (CμPO2), and medullar microcirculatory pO2 (MμPO2) are measured by the oxygen-dependent quenching of the phosphorescence lifetime technique. Renal functional, inflammatory, and tissues damage parameters were also assessed. HS, but not NS, treatment restored I/R-induced reduced mean arterial pressure, CμPO2, renal oxygen deliver (DO2ren), and consumption (VO2ren). HS caused a decrease in tubular sodium reabsorption (TNa) that correlated with an elevation of fractional sodium excretion (EFNa) and urine output. HS had an anti-inflammatory effect by reducing the levels TNF-α, IL-6, and hyaluronic acid in the renal tissue samples as compared with the I/R and I/R+NS groups (P < 0.05). HS treatment was also associated with mild acidosis and an increased renal tubular damage. Despite HS resuscitation improving the systemic hemodynamics, microcirculatory oxygenation, and renal oxygen consumption as well as inflammation, it should be limited or strictly controlled for long-term use because of provoking widespread renal structural damage.

Use, misuse and abuse of diuretics.

PubMed

Bartoli, Ettore; Rossi, Luca; Sola, Daniele; Castello, Luigi; Sainaghi, Pier Paolo; Smirne, Carlo

2017-04-01

Resolution of edema requires a correct interpretation of body fluids-related renal function, to excrete the excess volume while restoring systemic hemodynamics and avoiding renal failure. In heart failure, the intensive diuresis should be matched by continuous fluids refeeding from interstitium to plasma, avoiding central volume depletion. The slowly reabsorbed ascites cannot refeed this contracted volume in cirrhosis: the ensuing activation of intrathoracic receptors, attended by increased adrenergic and Renin release, causes more avid sodium retention, producing a positive fluid and Na balance in the face of continuous treatment. High-dose-furosemide creates a defect in tubular Na causing diuresis adequate to excrete the daily water and electrolyte load in Chronic Renal Failure. Diuretic treatment requires care, caution and bedside "tricks" aimed at minimizing volume contraction by correctly assessing the homeostatic system of body fluids and related renal hemodynamics. Copyright © 2017 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Blockade of renal medullary bradykinin B2 receptors increases tubular sodium reabsorption in rats fed a normal-salt diet

PubMed Central

Sivritas, Sema-Hayriye; Ploth, David W.; Fitzgibbon, Wayne R.

2008-01-01

The present study was performed to test the hypothesis that under normal physiological conditions and/or during augmentation of kinin levels, intrarenal kinins act on medullary bradykinin B2 (BKB2) receptors to acutely increase papillary blood flow (PBF) and therefore Na+ excretion. We determined the effect of acute inner medullary interstitial (IMI) BKB2 receptor blockade on renal hemodynamics and excretory function in rats fed either a normal (0.23%)- or a low (0.08%)-NaCl diet. For each NaCl diet, two groups of rats were studied. Baseline renal hemodynamic and excretory function were determined during IMI infusion of 0.9% NaCl into the left kidney. The infusion was then either changed to HOE-140 (100 μg·kg−1·h−1, treated group) or maintained with 0.9% NaCl (time control group), and the parameters were again determined. In rats fed a normal-salt diet, HOE-140 infusion decreased left kidney Na+ excretion (urinary Na+ extraction rate) and fractional Na+ excretion by 40 ± 5% and 40 ± 4%, respectively (P < 0.01), but did not alter glomerular filtration rate, inner medullary blood flow (PBF), or cortical blood flow. In rats fed a low-salt diet, HOE-140 infusion did not alter renal regional hemodynamics or excretory function. We conclude that in rats fed a normal-salt diet, kinins act tonically via medullary BKB2 receptors to increase Na+ excretion independent of changes in inner medullary blood flow. PMID:18632797

Central Body Fat Distribution Associates with Unfavorable Renal Hemodynamics Independent of Body Mass Index

PubMed Central

Zelle, Dorien M.; Bakker, Stephan J.L.; Navis, Gerjan

2013-01-01

Central distribution of body fat is associated with a higher risk of renal disease, but whether it is the distribution pattern or the overall excess weight that underlies this association is not well understood. Here, we studied the association between waist-to-hip ratio (WHR), which reflects central adiposity, and renal hemodynamics in 315 healthy persons with a mean body mass index (BMI) of 24.9 kg/m2 and a mean 125I-iothalamate GFR of 109 ml/min per 1.73 m2. In multivariate analyses, WHR was associated with lower GFR, lower effective renal plasma flow, and higher filtration fraction, even after adjustment for sex, age, mean arterial pressure, and BMI. Multivariate models produced similar results regardless of whether the hemodynamic measures were indexed to body surface area. Thus, these results suggest that central body fat distribution, independent of BMI, is associated with an unfavorable pattern of renal hemodynamic measures that could underlie the increased renal risk reported in observational studies. PMID:23578944

Cardiorenal Syndrome in Acute Heart Failure: Revisiting Paradigms.

PubMed

Núñez, Julio; Miñana, Gema; Santas, Enrique; Bertomeu-González, Vicente

2015-05-01

Cardiorenal syndrome has been defined as the simultaneous dysfunction of both the heart and the kidney. Worsening renal function that occurs in patients with acute heart failure has been classified as cardiorenal syndrome type 1. In this setting, worsening renal function is a common finding and is due to complex, multifactorial, and not fully understood processes involving hemodynamic (renal arterial hypoperfusion and renal venous congestion) and nonhemodynamic factors. Traditionally, worsening renal function has been associated with worse outcomes, but recent findings have revealed mixed and heterogeneous results, perhaps suggesting that the same phenotype represents a diversity of pathophysiological and clinical situations. Interpreting the magnitude and chronology of renal changes together with baseline renal function, fluid overload status, and clinical response to therapy might help clinicians to unravel the clinical meaning of renal function changes that occur during an episode of heart failure decompensation. In this article, we critically review the contemporary evidence on the pathophysiology and clinical aspects of worsening renal function in acute heart failure. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Ischemia and reperfusion injury in renal transplantation: hemodynamic and immunological paradigms

PubMed Central

Requião-Moura, Lúcio Roberto; Durão, Marcelino de Souza; de Matos, Ana Cristina Carvalho; Pacheco-Silva, Alvaro

2015-01-01

Ischemia and reperfusion injury is an inevitable event in renal transplantation. The most important consequences are delayed graft function, longer length of stay, higher hospital costs, high risk of acute rejection, and negative impact of long-term follow-up. Currently, many factors are involved in their pathophysiology and could be classified into two different paradigms for education purposes: hemodynamic and immune. The hemodynamic paradigm is described as the reduction of oxygen delivery due to blood flow interruption, involving many hormone systems, and oxygen-free radicals produced after reperfusion. The immune paradigm has been recently described and involves immune system cells, especially T cells, with a central role in this injury. According to these concepts, new strategies to prevent ischemia and reperfusion injury have been studied, particularly the more physiological forms of storing the kidney, such as the pump machine and the use of antilymphocyte antibody therapy before reperfusion. Pump machine perfusion reduces delayed graft function prevalence and length of stay at hospital, and increases long-term graft survival. The use of antilymphocyte antibody therapy before reperfusion, such as Thymoglobulin™, can reduce the prevalence of delayed graft function and chronic graft dysfunction. PMID:25993079

Droxidopa, an oral norepinephrine precursor, improves hemodynamic and renal alterations of portal hypertensive rats.

PubMed

Coll, Mar; Rodriguez, Sarai; Raurell, Imma; Ezkurdia, Nahia; Brull, Astrid; Augustin, Salvador; Guardia, Jaime; Esteban, Rafael; Martell, María; Genescà, Joan

2012-11-01

We aimed to evaluate the effects of droxidopa (an oral synthetic precursor of norepinephrine) on the hemodynamic and renal alterations of portal hypertensive rats. Sham, portal vein-ligated (PVL), and 4-week biliary duct-ligated (BDL) rats received a single oral dose of droxidopa (25-50 mg/kg) or vehicle and hemodynamic parameters were monitored for 2 hours. Two groups of BDL and cirrhotic rats induced by carbon tetrachloride (CCl(4) ) were treated for 5 days with droxidopa (15 mg/kg, twice daily, orally); hemodynamic parameters and blood and urinary parameters were assessed. The droxidopa effect on the Rho kinase (RhoK) / protein kinase B (AKT) / endothelial nitric oxide synthase (eNOS) pathways was analyzed by western blot in superior mesenteric artery (SMA). The acute administration of droxidopa in PVL and BDL rats caused a significant and maintained increase in arterial pressure and mesenteric arterial resistance, with a significant decrease of mesenteric arterial and portal blood flow, without changing portal pressure and renal blood flow. Two-hour diuresis greatly increased. Carbidopa (DOPA decarboxylase inhibitor) blunted all effects of droxidopa. Chronic droxidopa therapy in BDL rats produced the same beneficial hemodynamic effects observed in the acute study, did not alter liver function parameters, and caused a 50% increase in 24-hour diuresis volume (7.4 ± 0.9 mL/100g in BDL vehicle versus 11.8 ± 2.5 mL/100g in BDL droxidopa; P = 0.01). Droxidopa-treated rats also showed a decreased ratio of p-eNOS/eNOS and p-AKT/AKT and increased activity of RhoK in SMA. The same chronic treatment in CCl(4) rats caused similar hemodynamic effects and produced significant increases in diuresis volume and 24-hour natriuresis (0.08 ± 0.02 mmol/100g in CCl(4) vehicle versus 0.23 ± 0.03 mmol/100g in CCl(4) droxidopa; P = 0.014). Droxidopa might be an effective therapeutic agent for hemodynamic and renal alterations of liver cirrhosis and should be tested in cirrhosis patients. Copyright © 2012 American Association for the Study of Liver Diseases.

Effect of increased venous pressure on renal hemodynamics.

DOT National Transportation Integrated Search

1962-10-01

Conflicting evidence exists in regard to the effects of increased venous pressure on renal hemodynamics. Experiments to clarify its role were carried on twenty-eight intact innervated or isolated perfused dog kidneys. Findings indicate the absence of...

From anatomy to function: diagnosis of atherosclerotic renal artery stenosis.

PubMed

Odudu, Aghogho; Vassallo, Diana; Kalra, Philip A

2015-12-01

Atherosclerotic renal artery stenosis (ARAS) affects 7% of the over 65 s and will be increasingly common with an ageing population. ARAS obstructs normal renal perfusion with adverse renal and cardiovascular consequences. Drug therapy is directed at reducing atherosclerotic risk. Two recent major trials of revascularization for ARAS showed that clinical outcomes were not improved beyond those offered by optimal drug therapy in most patients. This reflects experimental data showing that restoration of blood flow alone may not attenuate a cascade of tissue injury. A shift from anatomic to functional imaging of ARAS coupled to novel therapies might improve clinical outcomes in selected patients. This review outlines the case for separately assessing hemodynamic significance of arterial stenosis and functional reserve of renal parenchymal tissue. The authors consider current and emerging diagnostic techniques for ARAS and their potential to allow individualized and functionally directed treatments.

The effect of direct renin inhibition alone and in combination with ACE inhibition on endothelial function, arterial stiffness, and renal function in type 1 diabetes.

PubMed

Cherney, David Z I; Scholey, James W; Jiang, Shan; Har, Ronnie; Lai, Vesta; Sochett, Etienne B; Reich, Heather N

2012-11-01

Diabetes is associated with renin-angiotensin system (RAS) activation, leading to renal and systemic vascular dysfunction that contribute to end-organ injury and significant morbidity. RAS blockade with ACE inhibitors reduces, but does not abolish, RAS effects. Accordingly, our aim was to determine if direct renin inhibition alone, and in combination with an ACE inhibitor, corrects early hemodynamic abnormalities associated with type 1 diabetes. Arterial stiffness (augmentation index), flow-mediated vasodilatation (FMD), and renal hemodynamic function (inulin and paraaminohippurate clearance) were measured at baseline under clamped euglycemic and hyperglycemic conditions (n = 21). Measures were repeated after 4 weeks of aliskiren therapy and again after aliskiren plus ramipril. Blood pressure-lowering effects of aliskiren were similar during clamped euglycemia and hyperglycemia. Combination therapy augmented this effect under both glycemic conditions (P = 0.0005). Aliskiren reduced arterial stiffness under clamped euglycemic and hyperglycemic conditions, and the effects were augmented by dual RAS blockade (-3.4 ± 11.2 to -8.0 ± 11.5 to -14.3 ± 8.4%, respectively, during euglycemia, P = 0.0001). During clamped euglycemia, aliskiren increased FMD; dual therapy exaggerated this effect (5.1 ± 3.3 to 7.5 ± 3.0 to 10.8 ± 3.5%, repeated-measures ANOVA, P = 0.0001). Aliskiren monotherapy caused renal vasodilatation during clamped hyperglycemia only. In contrast, dual therapy augmented renal vasodilatory effects during clamped euglycemia and hyperglycemia. In patients with uncomplicated type 1 diabetes, aliskiren-based dual RAS blockade is associated with greater arterial compliance, FMD, and renal vasodilatation.

Carotid artery wall shear stress is independently correlated with renal function in the elderly.

PubMed

Guo, Yuqi; Wei, Fang; Wang, Juan; Zhao, Yingxin; Sun, Shangwen; Zhang, Hua; Liu, Zhendong

2018-01-12

Hemodynamic has increasingly been regarded as an important factor of renal function. However, the relationship between carotid artery wall shear stress (WSS) and renal function is not clarified. To investigate the relationship between carotid WSS and renal function, we recruited 761 older subjects aged 60 years and over from community-dwelling in the Shandong area, China. Carotid WSS, endothelial function, and estimated glomerular filtration rate (eGFR) were assessed in all subjects. Subjects were grouped by the interquartile of the carotid artery mean WSS. We found that the eGFRs derived from serum creatinine and/or cystatin C using three CKD-EPI equations were significantly higher and albumin/creatinine ratio was lower in the higher interquartile groups than in the lower interquartile groups ( P <0.05). The mean WSS was independently correlated with eGFRs even after adjustment for confounders. Similar findings were found between carotid artery peak WSS and eGFRs and albumin/creatinine ratio. In addition, we found that endothelial function was strongly related to carotid WSS and renal function after adjustment for confounders. In conclusion, there is an independent correlation of carotid WSS with renal function in the elderly. The local rheologic forces may play an important role in renal function changing. The correlation may be mediated by regulation of endothelial function.

Fetal development and renal function in adult rats prenatally subjected to sodium overload.

PubMed

Cardoso, Henriqueta D; Cabral, Edjair V; Vieira-Filho, Leucio D; Vieyra, Adalberto; Paixão, Ana D O

2009-10-01

The aims of this study were (1) to evaluate two factors that affect fetal development--placental oxidative stress (Ox) and plasma volume (PV)--in dams with sodium overload and (2) to correlate possible alterations in these factors with subsequent modifications in the renal function of adult offspring. Wistar dams were maintained on 0.17 M NaCl instead of water from 20 days before mating until either the twentieth pregnancy day/parturition or weaning. Colorimetric methods were used to measure Ox in maternal and offspring tissues, PV, 24-h urinary protein (U(Prot24 h)) and serum triacylglycerols (TG) and cholesterol (Chol). Renal hemodynamics was evaluated in the offspring at 90 days of age using a blood pressure transducer, a flow probe and inulin clearance to measure mean arterial pressure (MAP), renal blood flow and glomerular filtration rate (GFR), respectively. The number of nephrons (NN) was counted in kidney suspensions. Dams showed unchanged PV, placental Ox and fetal weight but increased U(Prot24 h) (150%, P < 0.05). Prenatally sodium-overloaded pups showed increased U(Prot24 h) (45%, P < 0.05) but unchanged MAP, renal hemodynamics, NN and kidney Ox. Prenatally and postnatally sodium-overloaded rats showed increased U(Prot24 h) (27%, P < 0.05) and kidney Ox (44%, P < 0.05), reduced GFR (12%, P < 0.05), increased PV (26%, P < 0.05) and unchanged MAP and NN. The TG increased in both groups of treated offspring (21%, P < 0.05), whereas Chol increased only in the postnatally sodium-overloaded group. We conclude that salt overload from the prenatal stage until weaning leads to alterations in lipid metabolism and in the renal function of the pups, which are additional to those alterations seen in rats only overloaded prenatally.

Hypothyroidism presenting as reversible renal impairment: an interesting case report.

PubMed

Vikrant, Sanjay; Chander, Subhash; Kumar, Satish; Gupta, Dalip

2013-10-01

We describe an interesting case of reversible renal impairment secondary to hypothyroidism. A 57-years-old man was referred from peripheral institution for evaluation of elevated serum creatinine. He had vague complaints of weakness, lethargy and muscle ache but no urinary symptoms. He was found to have hypothyroidism, and thyroid hormone replacement therapy (THRT) was started which resulted in reversal of the renal dysfunction. There was marked improvement in estimated glomerular filtration rate. 99mTc DTPA renal scans done before and after THRT suggested hypothyroidism responsible for this reversible renal impairment. Several studies have described the pathophysiology of diminished renal function in hypothyroidism. Few studies or case reports have shown total amelioration of renal impairment as seen in our patient. The etiology is presumed to be multifactorial, in which hemodynamic effects and a direct effect of thyroid hormone on the kidney play an important role. We suggest that patients with renal impairment of unknown cause have thyroid function tests undertaken as part of routine investigation.

Low-flow CO₂ removal integrated into a renal-replacement circuit can reduce acidosis and decrease vasopressor requirements.

PubMed

Forster, Christian; Schriewer, Jens; John, Stefan; Eckardt, Kai-Uwe; Willam, Carsten

2013-07-24

Lung-protective ventilation in patients with ARDS and multiorgan failure, including renal failure, is often paralleled with a combined respiratory and metabolic acidosis. We assessed the effectiveness of a hollow-fiber gas exchanger integrated into a conventional renal-replacement circuit on CO₂ removal, acidosis, and hemodynamics. In ten ventilated critically ill patients with ARDS and AKI undergoing renal- and respiratory-replacement therapy, effects of low-flow CO₂ removal on respiratory acidosis compensation were tested by using a hollow-fiber gas exchanger added to the renal-replacement circuit. This was an observational study on safety, CO₂-removal capacity, effects on pH, ventilator settings, and hemodynamics. CO₂ elimination in the low-flow circuit was safe and was well tolerated by all patients. After 4 hours of treatment, a mean reduction of 17.3 mm Hg (-28.1%) pCO₂ was observed, in line with an increase in pH. In hemodynamically instable patients, low-flow CO₂ elimination was paralleled by hemodynamic improvement, with an average reduction of vasopressors of 65% in five of six catecholamine-dependent patients during the first 24 hours. Because no further catheters are needed, besides those for renal replacement, the implementation of a hollow-fiber gas exchanger in a renal circuit could be an attractive therapeutic tool with only a little additional trauma for patients with mild to moderate ARDS undergoing invasive ventilation with concomitant respiratory acidosis, as long as no severe oxygenation defects indicate ECMO therapy.

Impact of high doses of 6% hydroxyethyl starch 130/0.42 and 4% gelatin on renal function in a pediatric animal model.

PubMed

Witt, Lars; Glage, Silke; Lichtinghagen, Ralf; Pape, Lars; Boethig, Dietmar; Dennhardt, Nils; Heiderich, Sebastian; Leffler, Andreas; Sümpelmann, Robert

2016-03-01

Despite serious renal side effects in critically ill adult patients, artificial colloids are still fundamental components of perioperative fluid therapy in infants and children, although the impact of 6% hydroxyethyl starch (HES) and 4% gelatin (GEL) on renal function during pediatric surgery has not been identified yet. To determine the impact of high doses of artificial colloids on renal function, we conducted an experimental animal study and hypothesized that neither the infusion of HES nor of GEL would have a serious impact on renal function. Fifteen sedated piglets were randomly assigned to receive an infusion of either 50 ml · kg(-1) HES or GEL, or a balanced electrolyte solution (crystalloid group). Before and 1 week after infusion, serum and urine renal function tests were recorded and renal biopsies were taken. Serum and urine renal function tests revealed no increase after administration of HES and GEL, and only a discrete increase in serum creatinine (median 9.8 μmol · l(-1), 95% CI 4.0-19.1) in the crystalloid group. Histopathological examination indicated a sparsely, multifocal infiltration of mononuclear cells in all groups and an unspecific pyelectasia of one animal in the GEL group. After high doses of HES or GEL in piglets, no relevant impact on renal function could be found. These results confirm that AKI after HES or GEL is very unlikely in hemodynamically stable perioperative patients with normal renal function. © 2015 John Wiley & Sons Ltd.

Anesthetic management of patients undergoing extra-anatomic renal bypass surgery for renovascular hypertension.

PubMed

Kumar, Bhupesh; Sinha, Prabhat Kumar; Unnikrishnan, M

2011-01-01

Renal artery disease is the most common cause for surgically curable form of hypertension. In a small subset of patients with severe aortic disease where the aorta is not suitable for endovascular technique and to provide an arterial inflow, an extra-anatomic renal bypass surgery (EARBS) is an option. Anesthetic management of such procedures has not been described so far in the literature. We retrospectively analyzed the anesthetic techniques used in all patients who underwent EARBS between February 1998 and June 2008 at this institute. We also further analyzed data concerning blood pressure (BP) control and renal function response following surgery as outcome variable measures. A total of 11 patients underwent EARBS during this period. Five received oral clonidine with premedication. During laryngoscopy, esmolol was used in 4 patients, while lignocaine was used in remaining 7 patients. Of 11 patients, 7 showed significant hemodynamic response to laryngoscopy and intubation; among these, one had oral clonidine with premedicant, and 6 received lignocaine just before laryngoscopy. Intravenous vasodilators were used to maintain target BP within 20% of baseline during perioperative period. All patients received renal protective measures. During follow-up, 10% were considered cured, 70% had improved BP response, while 20% failed to show improvement in BP response. Renal functions improved in 54.5%, remain unchanged in 36.5%, and worsened in 9% of patients. Use of clonidine during premedication and esmolol before laryngoscopy were beneficial in attenuating hemodynamic response to laryngoscopy, while use of vasodilators to maintain target BP within 20% of baseline, and routine use of renal protective measures appear to be promising in patients undergoing EARBS.

Multimarker assessment for the prediction of renal function improvement after percutaneous revascularization for renal artery stenosis.

PubMed

Staub, Daniel; Partovi, Sasan; Zeller, Thomas; Breidthardt, Tobias; Kaech, Max; Boeddinghaus, Jasper; Puelacher, Christian; Nestelberger, Thomas; Aschwanden, Markus; Mueller, Christian

2016-06-01

Identifying patients likely to have improved renal function after percutaneous transluminal renal angioplasty and stenting (PTRA) for renal artery stenosis (RAS) is challenging. The purpose of this study was to use a comprehensive multimarker assessment to identify those patients who would benefit most from correction of RAS. In 127 patients with RAS and decreased renal function and/or hypertension referred for PTRA, quantification of hemodynamic cardiac stress using B-type natriuretic peptide (BNP), renal function using estimated glomerular filtration rate (eGFR), parenchymal renal damage using resistance index (RI), and systemic inflammation using C-reactive protein (CRP) were performed before intervention. Predefined renal function improvement (increase in eGFR ≥10%) at 6 months occurred in 37% of patients. Prognostic accuracy as quantified by the area under the receiver-operating characteristics curve for the ability of BNP, eGFR, RI and CRP to predict renal function improvement were 0.59 (95% CI, 0.48-0.70), 0.71 (95% CI, 0.61-0.81), 0.52 (95% CI, 0.41-0.65), and 0.56 (95% CI, 0.44-0.68), respectively. None of the possible combinations increased the accuracy provided by eGFR (lower eGFR indicated a higher likelihood for eGFR improvement after PTRA, P=ns for all). In the subgroup of 56 patients with pre-interventional eGFR <60 mL/min/1.73 m(2), similar findings were obtained. Quantification of renal function, but not any other pathophysiologic signal, provides at least moderate accuracy in the identification of patients with RAS in whom PTRA will improve renal function.

Effects of Direct Renin Blockade on Renal & Systemic Hemodynamics and on RAAS Activity, in Weight Excess and Hypertension: A Randomized Clinical Trial.

PubMed

Kwakernaak, A J; Roksnoer, L C; Lambers Heerspink, H J; van den Berg-Garrelds, I; Lochorn, G A; van Embden Andres, J H; Klijn, M A; Kobori, H; Danser, A H J; Laverman, G D; Navis, G J

2017-01-01

The combination of weight excess and hypertension significantly contributes to cardiovascular risk and progressive kidney damage. An unfavorable renal hemodynamic profile is thought to contribute to this increased risk and may be ameliorated by direct renin inhibition (DRI). The aim of this trial was to assess the effect of DRI on renal and systemic hemodynamics and on RAAS activity, in men with weight excess and hypertension. A randomized, double-blind, cross-over clinical trial to determine the effect of DRI (aliskiren 300 mg/day), with angiotensin converting enzyme inhibition (ACEi; ramipril 10 mg/day) as a positive control, on renal and systemic hemodynamics, and on RAAS activity (n = 15). Mean (SEM) Glomerular filtration rate (101 (5) mL/min/1.73m2) remained unaffected by DRI or ACEi. Effective renal plasma flow (ERPF; 301 (14) mL/min/1.73m2) was increased in response to DRI (320 (14) mL/min/1.73m2, P = 0.012) and ACEi (317 (15) mL/min/1.73m2, P = 0.045). Filtration fraction (FF; 34 (0.8)%) was reduced by DRI only (32 (0.7)%, P = 0.044). Mean arterial pressure (109 (2) mmHg) was reduced by DRI (101 (2) mmHg, P = 0.008) and ACEi (103 (3) mmHg, P = 0.037). RAAS activity was reduced by DRI and ACEi. Albuminuria (20 [9-42] mg/d) was reduced by DRI only (12 [5-28] mg/d, P = 0.030). In men with weight excess and hypertension, DRI and ACEi improved renal and systemic hemodynamics. Both DRI and ACEi reduced RAAS activity. Thus, DRI provides effective treatment in weight excess and hypertension. Dutch trial register, registration number: 2532 www.trialregister.nl.

Pathogenesis of diabetic nephropathy.

PubMed

Raptis, A E; Viberti, G

2001-01-01

Diabetic Nephropathy (DN) is the commonest cause of end-stage renal failure (ESRF) in the Western world. Diabetic nephropathy follows a well outline clinical course, starting with microalbuminuria through proteinuria, azotaemia and culminating in ESRF. Before the onset of overt proteinuria, there are various renal functional changes including renal hyperfiltration, hyperperfusion, and increasing capillary permeability to macromolecules. Basement-membrane thickening and mesangial expansion have long been recognized as pathological hallmark of diabetes. It has been postulated that DN occurs as a result of the interplay of metabolic and hemodynamic factors in the renal microcirculation. There is no doubt that there is a positive relationship between hyperglycaemia, which is necessary but not sufficient, and microvascular complications. The accumulation of advanced glycosylated end-products (AGEs), the activation of isoform(s) of protein kinase C (PKC) and the acceleration of the aldose reductase pathway may explain how hyperglycemia damages tissue. PKC is one of the key signaling molecules in the induction of the vascular pathology of diabetes. The balance between extracellular matrix production and degradation is important in this context. Transforming growth factor-beta (TGF-beta) appears to play a pivotal role in accumulation in the diabetic kidney. Hemodynamic disturbances are believed to be directly responsible for the development of glomerulosclerosis and its attendant proteinuria. There is familial clustering of diabetic kidney disease. A number of gene loci have been investigated to try to explain the genetic susceptibility to diabetic nephropathy. The genes coding for components of renin-angiotensin system have drawn special attention, due to the central role that this system plays in the regulation of blood pressure, sodium metabolism, and renal hemodynamics. Endothelial dysfunction is closely associated with the development of diabetic retinopathy, nephropathy and atherosclerosis, both in IDDM and in NIDDM. The pathogenesis of diabetic nephropathy is not clarified completely yet.

[Cardio-Pulmonary-Renal interactions].

PubMed

Samoni, Sara; Husain-Syed, Faeq; De Rosa, Silvia; Ronco, Claudio

2017-03-01

Over the past decade, understanding about feedback mechanisms involving the heart, lung and kidney is significantly improved. Each organ injury may trigger hemodynamic, neuro-hormonal and cellular pathway that may damage diverse organs. Recurrent acute on chronic injury may lead to the advanced stage of disease. On the other hand, chronic pathological conditions may decrease functional reserve leading to a high susceptibility to acute injury. Assessment of functional reserve and dosage of novel biomarkers may allow an early diagnosis and treatment. This review summarizes the current state-of-the-art understanding of cardio-pulmonary-renal interactions. Copyright by Società Italiana di Nefrologia SIN, Rome, Italy.

[Perioperative acute kidney injury and failure].

PubMed

Chhor, Vibol; Journois, Didier

2014-04-01

Perioperative period is very likely to lead to acute renal failure because of anesthesia (general or perimedullary) and/or surgery which can cause acute kidney injury. Characterization of acute renal failure is based on serum creatinine level which is imprecise during and following surgery. Studies are based on various definitions of acute renal failure with different thresholds which skewed their comparisons. The RIFLE classification (risk, injury, failure, loss, end stage kidney disease) allows clinicians to distinguish in a similar manner between different stages of acute kidney injury rather than using a unique definition of acute renal failure. Acute renal failure during the perioperative period can mainly be explained by iatrogenic, hemodynamic or surgical causes and can result in an increased morbi-mortality. Prevention of this complication requires hemodynamic optimization (venous return, cardiac output, vascular resistance), discontinuation of nephrotoxic drugs but also knowledge of the different steps of the surgery to avoid further degradation of renal perfusion. Diuretics do not prevent acute renal failure and may even push it forward especially during the perioperative period when venous retourn is already reduced. Edema or weight gain following surgery are not correlated with the vascular compartment volume, much less with renal perfusion. Treatment of perioperative acute renal failure is similar to other acute renal failure. Renal replacement therapy must be mastered to prevent any additional risk of hemodynamic instability or hydro-electrolytic imbalance. Copyright © 2014 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Renal functional reserve and renal hemodynamics in hypertensive patients.

PubMed

Gaipov, Abduzhappar; Solak, Yalcin; Zhampeissov, Nurlan; Dzholdasbekova, Aliya; Popova, Nadezhda; Molnar, Miklos Z; Tuganbekova, Saltanat; Iskandirova, Elmira

2016-10-01

The renal functional reserve (RFR) is the ability of the kidneys to increase renal plasma flow and glomerular filtration rate (GFR) in response to protein intake. It is a measure of functional and anatomic integrity of nephrons. It is not known what relation between RFR and kidney Doppler parameters. We aimed to study the relation between the RFR and renal hemodynamic parameters in hypertensive patients with and without nephropathy who had normal kidney function. Twenty-four hypertensive subjects with nephropathy (HTN-n, n = 10) and hypertension without nephropathy (HTN, n = 14) were included in the study. Control group included 11 healthy subjects. Baseline GFR (GFR1) and GFR after intake of egg protein 1 mg/kg of body weight were determined (GFR2). RFR was calculated by the following formula: (GFR2-GFR1)/GFR1 × 100%. Doppler ultrasonography was performed. Arterial blood pressure (BP), body mass index (BMI), and estimated GFR were also recorded. HTN and HTN-n groups had impaired levels of RFR compared with controls (p < 0.05), significantly decreased value of flow velocity parameters (Vmax, Vmin), and increased RRI compared with controls. There was significant negative correlation of RFR with blood pressure levels (sBP, r = -0.435, p = 0.009; dBP, r = -0.504, p = 0.002), RRI (r = -0.456, p = 0.008), micro albuminuria (MAU, r = -0.366, p = 0.031) and positive correlation with Vmax and Vmin (r = 0.556, p = 0.001 and r = 0.643, respectively, p < 0.001). Linear regression showed that RRI and MAU were independent predictors of decreased RFR. RFR is lower in hypertensive patients despite near-normal level of kidney function and is related to particular level of BP. RRI and MAU were independent predictors of decreased RFR.

Proceedings of the First Joint NASA Cardiopulmonary Workshop

NASA Technical Reports Server (NTRS)

Fortney, Suzanne M. (Editor); Hargens, Alan R. (Editor)

1991-01-01

The topics covered include the following: flight echocardiography, pulmonary function, central hemodynamics, glycerol hyperhydration, spectral analysis, lower body negative pressure countermeasures, orthostatic tolerance, autonomic function, cardiac deconditioning, fluid and renal responses to head-down tilt, local fluid regulation, endocrine regulation during bed rest, autogenic feedback, and chronic cardiovascular measurements. The program ended with a general discussion of weightlessness models and countermeasures.

Eccentric LVH healing after starting renal replacement therapy.

PubMed

Vertolli, Ugo; Lupia, Mario; Naso, Agostino

2002-01-01

Hypertension and left ventricular hypertrophy (LVH) are commonly associated in patients with CRF starting RDT. We report a case of eccentric LVH with marked dilatation and subsequent mitral incompetence of +3/4 that disappeared after three months of standard hemodialysis. Mrs SN, 62 years old, starting HD, had an echocardiography because of dyspnoea; the echo showed: dilated left atrium (78 ml/m2), moderately dilated left ventricle with normal systolic function (TDV 81 ml/m2, EF 66%), an increased ventricular mass (120 gr/m2) and a high grade mitral incompetence +3/4. After three months standard RDT and a dry weight only 2 kg less, the patients was normotensive without therapy, a cardiac angiogram with a hemodynamic study was performed as a pre-transplant workout: a normal left ventricle was found with normal systolic function (TDV 66, TSV 17, GS 49, EF 75%), and a perfectly competent mitral valve (reflux disappeared). The coronary angiography did not reveal critical stenosis. A new echocardiography confinned the data of the hemodynamic study: hypertensive cardiomiopathy with normal systolic function. After one year the patient has been transplanted, with a good renal function and the cardiac echo unchanged. Relieving uremic toxicity ameliorated the cardiac performance in this particular patient.

Multimarker assessment for the prediction of renal function improvement after percutaneous revascularization for renal artery stenosis

PubMed Central

Partovi, Sasan; Zeller, Thomas; Breidthardt, Tobias; Kaech, Max; Boeddinghaus, Jasper; Puelacher, Christian; Nestelberger, Thomas; Aschwanden, Markus; Mueller, Christian

2016-01-01

Background Identifying patients likely to have improved renal function after percutaneous transluminal renal angioplasty and stenting (PTRA) for renal artery stenosis (RAS) is challenging. The purpose of this study was to use a comprehensive multimarker assessment to identify those patients who would benefit most from correction of RAS. Methods In 127 patients with RAS and decreased renal function and/or hypertension referred for PTRA, quantification of hemodynamic cardiac stress using B-type natriuretic peptide (BNP), renal function using estimated glomerular filtration rate (eGFR), parenchymal renal damage using resistance index (RI), and systemic inflammation using C-reactive protein (CRP) were performed before intervention. Results Predefined renal function improvement (increase in eGFR ≥10%) at 6 months occurred in 37% of patients. Prognostic accuracy as quantified by the area under the receiver-operating characteristics curve for the ability of BNP, eGFR, RI and CRP to predict renal function improvement were 0.59 (95% CI, 0.48–0.70), 0.71 (95% CI, 0.61–0.81), 0.52 (95% CI, 0.41–0.65), and 0.56 (95% CI, 0.44–0.68), respectively. None of the possible combinations increased the accuracy provided by eGFR (lower eGFR indicated a higher likelihood for eGFR improvement after PTRA, P=ns for all). In the subgroup of 56 patients with pre-interventional eGFR <60 mL/min/1.73 m2, similar findings were obtained. Conclusions Quantification of renal function, but not any other pathophysiologic signal, provides at least moderate accuracy in the identification of patients with RAS in whom PTRA will improve renal function. PMID:27280085

Hemodynamic Measurements for the Selection of Patients With Renal Artery Stenosis: A Systematic Review.

PubMed

van Brussel, Peter M; van de Hoef, Tim P; de Winter, Robbert J; Vogt, Liffert; van den Born, Bert-Jan

2017-05-22

Interventions targeting renal artery stenoses have been shown to lower blood pressure and preserve renal function. In recent studies, the efficacy of catheter-based percutaneous transluminal renal angioplasty with stent placement has been called into question. In the identification of functional coronary lesions, hyperemic measurements have earned a place in daily practice for clinical decision making, allowing discrimination between solitary coronary lesions and diffuse microvascular disease. Next to differences in clinical characteristics, the selection of renal arteries suitable for intervention is currently on the basis of anatomic grading of the stenosis by angiography rather than functional assessment under hyperemia. It is conceivable that, like the coronary circulation, functional measurements may better predict therapeutic efficacy of percutaneous transluminal renal angioplasty with stent placement. In this systematic review, the authors evaluate the available clinical evidence on the optimal hyperemic agents to induce intrarenal hyperemia, their association with anatomic grading, and their predictive value for treatment effects. In addition, the potential value of combined pressure and flow measurements to discriminate macrovascular from microvascular disease is discussed. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Angiotensin receptors modulate the renal hemodynamic effects of nitric oxide in conscious newborn lambs

PubMed Central

Vinturache, Angela E.; Smith, Francine G.

2014-01-01

Abstract This study aimed to elucidate the roles of both angiotensin II (ANG II) receptors – type 1 (AT1Rs) and type 2 (AT2Rs) – separately and together in influencing hemodynamic effects of endogenously produced nitric oxide (NO) during postnatal development. In conscious, chronically instrumented lambs aged ~1 week (8 ± 1 days, N = 8) and ~6 weeks (41 ± 2 days, N = 8), systolic, diastolic, and mean arterial pressure (SAP, DAP, MAP) and venous pressure (MVP), renal blood flow (RBF), and renal vascular resistance (RVR) were measured in response to the l‐arginine analog, l‐NAME after pretreatment with either the AT1R antagonist, ZD 7155, the AT2R antagonist, PD 123319, or both antagonists. The increase in SAP, DAP, and MAP by l‐NAME was not altered by either ATR antagonist in either age group. The increase in RBF after l‐NAME was, however, altered by both ATR antagonists in an age‐dependent manner, which was mediated predominantly through AT2Rs in newborn lambs. These findings reveal that there is an age‐dependent interaction between the renin–angiotensin (RAS) and the NO pathway in regulating renal but not systemic hemodynamics through both ATRs, whereas AT2Rs appear to be important in the renal hemodynamic effects of NO early in life. PMID:24872358

Functional significance of the pattern of renal sympathetic nerve activation.

PubMed

Dibona, G F; Sawin, L L

1999-08-01

To assess the renal functional significance of the pattern of renal sympathetic nerve activation, computer-generated stimulus patterns (delivered at constant integrated voltage) were applied to the decentralized renal sympathetic nerve bundle and renal hemodynamic and excretory responses determined in anesthetized rats. When delivered at the same integrated voltage, stimulus patterns resembling those observed in in vivo multifiber recordings of renal sympathetic nerve activity (diamond-wave patterns) produced greater renal vasoconstrictor responses than conventional square-wave patterns. Within diamond-wave patterns, increasing integrated voltage by increasing amplitude produced twofold greater renal vasoconstrictor responses than by increasing duration. With similar integrated voltages that were subthreshold for renal vasoconstriction, neither diamond- nor square-wave pattern altered glomerular filtration rate, whereas diamond- but not square-wave pattern reversibly decreased urinary sodium excretion by 25 +/- 3%. At the same number of pulses per second, intermittent stimulation produced faster and greater renal vasoconstriction than continuous stimulation. At the same number of pulses per second, increases in rest period during intermittent stimulation proportionally augmented the renal vasoconstrictor response compared with that observed with continuous stimulation; the maximum augmentation of 55% occurred at a rest period of 500 ms. These results indicate that the pattern of renal sympathetic nerve stimulation (activity) significantly influences the rapidity, magnitude, and selectivity of the renal vascular and tubular responses.

Effects of positive acceleration /+Gz/ on renal function and plasma renin in normal man

NASA Technical Reports Server (NTRS)

Epstein, M.; Shubrooks, S. J., Jr.; Fishman, L. M.; Duncan, D. C.

1974-01-01

The effects of positive radial centrifugation (+Gz) on plasma resin activity (PRA) and renal function were assessed in 15 normal male subjects under carefully controlled conditions of Na, K, and water intake. Twenty minutes of +2.0 Gz resulted in significant decreases in the mean rate of sodium excretion and creatine clearance and in a doubling of PRA in seven sodium-depleted subjects (10 meq Na intake). In eight sodium-replete subjects (200 mq Na intake), 30 min of +2.0 Gz was also associated with a decrease in the mean rate of sodium excretion. As a consequence of a concurrent decrease in creatine clearance, the fractional excretion of sodium during centrifugation did not differ from control, suggesting that the changes in Na excretion were mediated primarily by renal hemodynamic factors, although enhanced renal tubular sodium reabsorption may also have played a role.

Clofibrate prevents and reverses the hemodynamic manifestations of hyperthyroidism in rats.

PubMed

Rodríguez-Gómez, Isabel; Cruz, Antonio; Moreno, Juan Manuel; Soler, Agatángelo; Osuna, Antonio; Vargas, Félix

2008-03-01

This study analyzed the effects of the chronic administration of clofibrate, a peroxisome proliferator-activated receptor-alpha (PPARalpha) agonist, on the development and established hemodynamic, morphologic, metabolic, and renal manifestations of hyperthyroidism in rats. The prevention study used four groups of male Wistar rats: control, clofibrate (240 mg/kg/day by gavage), T(4)(75 microg thyroxine/rat/day s.c.), and T(4)+clofibrate. All treatments were maintained for 3 weeks. Body weight (BW), tail systolic blood pressure (SBP), and heart rate (HR) were recorded weekly. Finally, temperature, SBP, pulse pressure (PP) and HR were recorded in conscious rats, and morphologic, metabolic, plasma, and renal variables were measured. The reversion study used two groups of rats, T(4)(treated for 6 weeks) and T(4)+clofibrate, measuring their hemodynamic variables and temperature for 3 weeks. T(4) increased BP, HR, PP, and temperature when compared with control rats. Clofibrate prevented and reversed the increase in SBP, HR, PP, and temperature produced by T(4) administration, reduced plasma thyroid hormone levels, and increased plasma thyroid-stimulating hormone values and phenol-uridine diphosphate-glucuronosyl-transferase (UGT) activity. However, clofibrate did not modify the cardiac or renal hypertrophy, polyphagia, polydipsia, or proteinuria of hyperthyroid rats. In normal rats, clofibrate treatment did not significantly change thyroid hormone levels, phenol-UGT activity, or any hemodynamic, morphologic, or renal variables. Chronic clofibrate treatment suppressed the hemodynamic manifestations and increased temperature of hyperthyroidism, an effect that can be produced by direct antithyroid effects. However, clofibrate administration did not modify the morphologic, metabolic, or renal alterations of hyperthyroid rats, indicating specificity in the antithyroid actions of clofibrate.

Acute systemic and renal hemodynamic effects of meglumine/sodium diatrizoate 76% and iopamidol in euvolemic and dehydrated dogs.

PubMed

Katzberg, R W; Morris, T W; Lasser, E C; DiMarco, P L; Merguerian, P A; Ventura, J A; Pabico, R C; McKenna, B A

1986-10-01

We examined the acute systemic and renal hemodynamic effects of intravenous meglumine/sodium diatrizoate-76% and iopamidol in euvolemic and dehydrated dogs. The physiologic responses were compared with acute changes in the level of an endogenous heparin-like material (EHM). One of eight dehydrated dogs receiving diatrizoate (2 ml/kg) had an immediate vomiting reflex associated with a very significant decline in all measured renal hemodynamic parameters; none of eight dehydrated dogs receiving iopamidol experienced a similar reaction. EHM levels did not correspond to the magnitude of the physiologic responses following either iopamidol or diatrizoate. Significant differences between iopamidol and diatrizoate were noted when comparing the magnitude of the decrease in systemic pressure (- delta 3.8 +/- 3.02, iopamidol, n = 8; vs. - delta 19.4 +/- 7.3 mm Hg, diatrizoate, n = 8; P less than .03), increased renal plasma flow (+ delta 6.2 +/- 4.9, iopamidol, n = 8; vs. + delta 33.7 +/- 8.0 ml/min, diatrizoate, n = 8; P less than .05), and decreased filtration fraction (- delta 0.09 +/- 0.01, iopamidol, n = 8; vs. - delta 0.14 +/- 0.02, diatrizoate, n = 8; P less than .03). There was no significant difference in the decrease in glomerular filtration rate (- delta 7.4 +/- 1.0, iopamidol, n = 8; vs. - delta 9.3 +/- 1.3, diatrizoate, n = 8; P greater than .05), since the marked drop in filtration fraction occurring with diatrizoate was counterbalanced by the marked increase in renal plasma flow. Acute systemic and renal hemodynamic effects are significantly lessened when comparing iopamidol with diatrizoate.

Effects of Direct Renin Blockade on Renal & Systemic Hemodynamics and on RAAS Activity, in Weight Excess and Hypertension: A Randomized Clinical Trial

PubMed Central

Kwakernaak, A. J.; Roksnoer, L. C.; Lambers Heerspink, H. J.; van den Berg-Garrelds, I.; Lochorn, G. A.; van Embden Andres, J. H.; Klijn, M. A.; Kobori, H.; Danser, A. H. J.; Laverman, G. D.; Navis, G. J.

2017-01-01

Aim The combination of weight excess and hypertension significantly contributes to cardiovascular risk and progressive kidney damage. An unfavorable renal hemodynamic profile is thought to contribute to this increased risk and may be ameliorated by direct renin inhibition (DRI). The aim of this trial was to assess the effect of DRI on renal and systemic hemodynamics and on RAAS activity, in men with weight excess and hypertension. Methods A randomized, double-blind, cross-over clinical trial to determine the effect of DRI (aliskiren 300 mg/day), with angiotensin converting enzyme inhibition (ACEi; ramipril 10 mg/day) as a positive control, on renal and systemic hemodynamics, and on RAAS activity (n = 15). Results Mean (SEM) Glomerular filtration rate (101 (5) mL/min/1.73m2) remained unaffected by DRI or ACEi. Effective renal plasma flow (ERPF; 301 (14) mL/min/1.73m2) was increased in response to DRI (320 (14) mL/min/1.73m2, P = 0.012) and ACEi (317 (15) mL/min/1.73m2, P = 0.045). Filtration fraction (FF; 34 (0.8)%) was reduced by DRI only (32 (0.7)%, P = 0.044). Mean arterial pressure (109 (2) mmHg) was reduced by DRI (101 (2) mmHg, P = 0.008) and ACEi (103 (3) mmHg, P = 0.037). RAAS activity was reduced by DRI and ACEi. Albuminuria (20 [9–42] mg/d) was reduced by DRI only (12 [5–28] mg/d, P = 0.030). Conclusions In men with weight excess and hypertension, DRI and ACEi improved renal and systemic hemodynamics. Both DRI and ACEi reduced RAAS activity. Thus, DRI provides effective treatment in weight excess and hypertension. Trial Registration Dutch trial register, registration number: 2532 www.trialregister.nl PMID:28118402

Clinical Correlates and Prognostic Value of Proenkephalin in Acute and Chronic Heart Failure.

PubMed

Matsue, Yuya; Ter Maaten, Jozine M; Struck, Joachim; Metra, Marco; O'Connor, Christopher M; Ponikowski, Piotr; Teerlink, John R; Cotter, Gad; Davison, Beth; Cleland, John G; Givertz, Michael M; Bloomfield, Daniel M; Dittrich, Howard C; van Veldhuisen, Dirk J; van der Meer, Peter; Damman, Kevin; Voors, Adriaan A

2017-03-01

Proenkephalin (pro-ENK) has emerged as a novel biomarker associated with both renal function and cardiac function. However, its clinical and prognostic value have not been well evaluated in symptomatic patients with heart failure. The association between pro-ENK and markers of renal function was evaluated in 95 patients with chronic heart failure who underwent renal hemodynamic measurements, including renal blood flow (RBF) and glomerular filtration rate (GFR) with the use of 131 I-Hippuran and 125 I-iothalamate clearances, respectively. The association between pro-ENK and clinical outcome in acute heart failure was assessed in another 1589 patients. Pro-ENK was strongly correlated with both RBF (P < .001) and GFR (P < .001), but not with renal tubular markers. In the acute heart failure cohort, pro-ENK was a predictor of death through 180 days, heart failure rehospitalization through 60 days, and death or cardiovascular or renal rehospitalization through day 60 in univariable analyses, but its predictive value was lost in a multivariable model when other renal markers were entered in the model. In patients with chronic and acute heart failure, pro-ENK is strongly associated with glomerular function, but not with tubular damage. Pro-ENK provides limited prognostic information in patients with acute heart failure on top of established renal markers. Copyright © 2016 Elsevier Inc. All rights reserved.

Renal Safety Pharmacology in Drug Discovery and Development.

PubMed

Benjamin, Amanda; Nogueira da Costa, Andre; Delaunois, Annie; Rosseels, Marie-Luce; Valentin, Jean-Pierre

2015-01-01

The kidney is a complex excretory organ playing a crucial role in various physiological processes such as fluid and electrolyte balance, control of blood pressure, removal of waste products, and drug disposition. Drug-induced kidney injury (DIKI) remains a significant cause of candidate drug attrition during drug development. However, the incidence of renal toxicities in preclinical studies is low, and the mechanisms by which drugs induce kidney injury are still poorly understood. Although some in vitro investigational tools have been developed, the in vivo assessment of renal function remains the most widely used methodology to identify DIKI. Stand-alone safety pharmacology studies usually include assessment of glomerular and hemodynamic function, coupled with urine and plasma analyses. However, as renal function is not part of the ICH S7A core battery, such studies are not routinely conducted by pharmaceutical companies. The most common approach consists in integrating renal/urinary measurements in repeat-dose toxicity studies. In addition to the standard analyses and histopathological examination of kidneys, novel promising urinary biomarkers have emerged over the last decade, offering greater sensitivity and specificity than traditional renal parameters. Seven of these biomarkers have been qualified by regulatory agencies for use in rat toxicity studies.

Acute dialysis and continuous renal replacement: the emergence of new technology involving the nephrologist in the intensive care setting.

PubMed

Yagi, N; Paganini, E P

1997-07-01

The emergence of dialytic support for patients with reversible renal failure was one of the most significant advances in critical care medicine. Supporting a patient with a failed organ till organ recovery has not had the same success with other organ failures. Despite the indispensable nature of the support, dialysis was intermittent at best, and carried its own morbidity. The emergence of a "continuous" dialysis delivery system, originally through an arteriovenous access and later through veno-venous methodology, began to simulate the continuity of the natural kidney, and lifted much of the fluid and drug restrictions imposed by the intermittent nature of standard dialytic therapies. Components of the system were next reviewed for improvement and biocompatability. Differences in patient outcome were documented with various component comparisons, and disparate patient tolerance of delivery modality was also clearly proven. The hemodynamic stability of continuous treatment created utilization to be focused on the more unstable, the more severely compromised patient group. In this context, comparative studies with intermittent delivery methods showed improved hemodynamic stability among patients treated with continuous renal replacement therapies (CRRT), but no clear difference in patient mortality. Patient characteristics and severity scoring have recently been undertaken to better describe the population, and attempts at dialysis dosing is currently being developed for ARF dialysis recipients. Early results seem to point toward a dialysis dose effect on mortality in certain groups of ICU acute renal failure patients. However, the dialytic process is only depurative and artificial. Plastic membrane bio-incompatibility, human physiological responses to foreign material exposure, either in the circuit material itself or introduced from therapy methodology, pose practical and theoretical problems. Recent advances in the field of bio-artificial technology have allowed the development of functioning hybrid "blood processors," which function as a renal tubule and may be able to not only "clean" blood, but also allow for other cellular functions not currently possible with dead membrane technology. Combining living cells with a continuous delivery method may be the next significant step toward a fully functional renal replacement therapy.

Effects of Arginase Inhibition in Hypertensive Hyperthyroid Rats.

PubMed

Rodríguez-Gómez, Isabel; Manuel Moreno, Juan; Jimenez, Rosario; Quesada, Andrés; Montoro-Molina, Sebastian; Vargas-Tendero, Pablo; Wangensteen, Rosemary; Vargas, Félix

2015-12-01

This study analyzed the effects of chronic administration of N[omega]-hydroxy-nor-l-arginine (nor-NOHA), an inhibitor of arginase, on the hemodynamic, oxidative stress, morphologic, metabolic, and renal manifestations of hyperthyroidism in rats. Four groups of male Wistar rats were used: control, nor-NOHA-treated (10 mg/kg/day), thyroxine (T4)-treated (75 μg/rat/day), and thyroxine- plus nor-NOHA-treated rats. All treatments were maintained for 4 weeks. Body weight, tail systolic blood pressure (SBP), and heart rate (HR) were recorded weekly. Finally, morphologic, metabolic, plasma, and renal variables were measured. Arginase I and II protein abundance and arginase activity were measured in aorta, heart, and kidney. The T4 group showed increased arginase I and II protein abundance, arginase activity, SBP, HR, plasma nitrates/nitrites (NOx), brainstem and urinary isoprostanes, proteinuria and cardiac and renal hypertrophy in comparison to control rats. In hyperthyroid rats, chronic nor-NOHA prevented the increase in SBP and HR and decreased proteinuria in association with an increase in plasma NOx and a decrease in brainstem and urinary isoprostanes. In normal rats, nor-NOHA treatment did not significantly change any hemodynamic, morphologic, or renal variables. Acute nor-NOHA administration did not affect renal or systemic hemodynamic variables in normal or T4-treated rats. Hyperthyroidism in rats is associated with the increased expression and activity of arginase in aorta, heart, and kidney. Chronic arginase inhibition with nor-NOHA suppresses the characteristic hemodynamic manifestations of hyperthyroidism in association with a reduced oxidative stress. These results indicate an important role for arginase pathway alterations in the cardiovascular and renal abnormalities of hyperthyroidism. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Graft function assessment in mouse models of single- and dual- kidney transplantation.

PubMed

Wang, Lei; Wang, Ximing; Jiang, Shan; Wei, Jin; Buggs, Jacentha; Fu, Liying; Zhang, Jie; Liu, Ruisheng

2018-05-23

Animal models of kidney transplantation (KTX) are widely used in studying immune response of hosts to implanted grafts. Additionally, KTX can be used in generating kidney-specific knockout animal models by transplantation of kidneys from donors with global knockout of a gene to wild type recipients or vise verse. Dual kidney transplantation (DKT) provides a more physiological environment for recipients than single kidney transplantation (SKT). However, DKT in mice is rare due to technical challenges. In this study, we successfully performed DKT in mice and compared the hemodynamic response and graft function with SKT. The surgical time, complications and survival rate of DKT were not significantly different from SKT, where survival rates were above 85%. Mice with DKT showed less injury and quicker recovery with lower plasma creatinine (Pcr) and higher GFR than SKT mice (Pcr = 0.34 and 0.17 mg/dl in DKT vs. 0.50 and 0.36 mg/dl in SKT at 1 and 3 days, respectively; GFR = 215 and 131 µl/min for DKT and SKT, respectively). In addition, the DKT exhibited better renal functional reserve and long-term outcome of renal graft function than SKT based on the response to acute volume expansion. In conclusion, we have successfully generated a mouse DKT model. The hemodynamic responses of DKT better mimic physiological situations with less kidney injury and better recovery than SKT because of reduced confounding factors such as single nephron hyperfiltration. We anticipate DKT in mice will provide an additional tool for evaluation of renal significance in physiology and disease.

Leukocyte and platelet depletion improves blood flow and function in a renal transplant model.

PubMed

Yates, Phillip J; Hosgood, Sarah A; Nicholson, Michael L

2012-01-01

Donation after cardiac death (DCD) donors are an important source of organs for transplantation. Due to warm and cold ischemic injury, DCD kidneys undergo a significant reperfusion insult when transplanted. This is manifested clinically as a high incidence of delayed graft function (DGF) and primary non-function (PNF). The importance of leukocytes in the generation of reperfusion injury is pivotal. Using an ex vivo porcine model of kidney transplantation, the effects of reperfusion with leukocyte and platelet depleted blood (LDB) and whole blood (WB) on renal blood flow and function were compared. Hemodynamic measurements were recorded, and biochemical, hematological, and histologic samples taken at set time-points. Reperfusion with LDB improved renal blood flow significantly compared with WB reperfusion. In addition, there was a significant improvement in creatinine clearance and renal oxygen consumption, but not fractional excretion of sodium, acid-base homeostasis, urinary nitric oxide (NO), or 8-isoprostane levels. This study represents a good model for the initial reperfusion period in renal transplantation. Improvement in only some functional markers and neither urinary NO nor 8-isoprostane levels indicates that improved blood flow alone is not sufficient to reverse the severe ischemic insult endured by DCD kidneys. Copyright © 2012 Elsevier Inc. All rights reserved.

Impact of the NO-Sensitive Guanylyl Cyclase 1 and 2 on Renal Blood Flow and Systemic Blood Pressure in Mice.

PubMed

Mergia, Evanthia; Thieme, Manuel; Hoch, Henning; Daniil, Georgios; Hering, Lydia; Yakoub, Mina; Scherbaum, Christina Rebecca; Rump, Lars Christian; Koesling, Doris; Stegbauer, Johannes

2018-03-23

Nitric oxide (NO) modulates renal blood flow (RBF) and kidney function and is involved in blood pressure (BP) regulation predominantly via stimulation of the NO-sensitive guanylyl cyclase (NO-GC), existing in two isoforms, NO-GC1 and NO-GC2. Here, we used isoform-specific knockout (KO) mice and investigated their contribution to renal hemodynamics under normotensive and angiotensin II-induced hypertensive conditions. Stimulation of the NO-GCs by S -nitrosoglutathione (GSNO) reduced BP in normotensive and hypertensive wildtype (WT) and NO-GC2-KO mice more efficiently than in NO-GC1-KO. NO-induced increase of RBF in normotensive mice did not differ between the genotypes, but the respective increase under hypertensive conditions was impaired in NO-GC1-KO. Similarly, inhibition of endogenous NO increased BP and reduced RBF to a lesser extent in NO-GC1-KO than in NO-GC2-KO. These findings indicate NO-GC1 as a target of NO to normalize RBF in hypertension. As these effects were not completely abolished in NO-GC1-KO and renal cyclic guanosine monophosphate (cGMP) levels were decreased in both NO-GC1-KO and NO-GC2-KO, the results suggest an additional contribution of NO-GC2. Hence, NO-GC1 plays a predominant role in the regulation of BP and RBF, especially in hypertension. However, renal NO-GC2 appears to compensate the loss of NO-GC1, and is able to regulate renal hemodynamics under physiological conditions.

Morphological and functional renovascular changes as cause of resistant arterial hypertension - case report and literature review.

PubMed

Costache, Irina Iuliana; Costea, Claudia Florida; Fotea, Vasile; Rusu, Victor Laurian; Aursulesei, Viviana; Al Namat, Razan; Costache, Dan Alexandru; Dumitrescu, Nicoleta; Buzdugă, Cătălin Mihai; Dumitrescu, Gabriela Florenţa; Sava, Anca; Bogdănici, Camelia Margareta

2018-01-01

Resistant hypertension is defined by the inability to maintain within normal limits the blood pressure values of an individual, while he is under treatment with maximal tolerated doses of three antihypertensive agents. One of the most common types of resistant hypertension is renovascular hypertension (RVH), which is caused by the narrowing of the renal arteries, in the context of existing atherosclerotic plaques at that level. We are presenting the case of a hypertensive 56-year-old man admitted in the Clinic of Cardiology for a sudden rise of his blood pressure values, despite undergoing the scheduled treatment. The abdominal bruit discovered at the clinical examination and the hypokalemia, together with the mild impairment of the renal function raised the suspicion of an existing stenosis of the main renal blood vessels. Simple grey scale kidney ultrasound, Doppler ultrasound of the renal arteries, abdominal computed tomography and magnetic resonance angiography of the renal arteries, along with invasive renal angiography demonstrated a smaller right kidney, adrenal incidentalomas, reduced vascular diameter of renal arteries due to atheromatous lesions, thrombosis of the infrarenal segment of the abdominal aorta, and reduced vascular hemodynamics in the same territories. After the renal arteries revascularization and with minimal antihypertensive treatment, the patient had a favorable outcome, with normalization of blood pressure and renal function. Atherosclerotic disease causing renal artery stenosis is essential to be taken into consideration in the etiopathogenesis of resistant hypertension especially because RVH is a potentially curable disease.

Intrarenal hemodynamic changes following acute partial renal arterial occlusion.

DOT National Transportation Integrated Search

1965-10-01

Both an increase and a decrease in total renal vascular resistance, following a period of total renal artery occlusion, have been reported from this laboratory. The duration of the occlusive period and height of the perfusion pressure were found to p...

Nephron Deficiency and Predisposition to Renal Injury in a Novel One-Kidney Genetic Model

PubMed Central

Wang, Xuexiang; Johnson, Ashley C.; Williams, Jan M.; White, Tiffani; Chade, Alejandro R.; Zhang, Jie; Liu, Ruisheng; Roman, Richard J.; Lee, Jonathan W.; Kyle, Patrick B.; Solberg-Woods, Leah

2015-01-01

Some studies have reported up to 40% of patients born with a single kidney develop hypertension, proteinuria, and in some cases renal failure. The increased susceptibility to renal injury may be due, in part, to reduced nephron numbers. Notably, children who undergo nephrectomy or adults who serve as kidney donors exhibit little difference in renal function compared with persons who have two kidneys. However, the difference in risk between being born with a single kidney versus being born with two kidneys and then undergoing nephrectomy are unclear. Animal models used previously to investigate this question are not ideal because they require invasive methods to model congenital solitary kidney. In this study, we describe a new genetic animal model, the heterogeneous stock-derived model of unilateral renal agenesis (HSRA) rat, which demonstrates 50%–75% spontaneous incidence of a single kidney. The HSRA model is characterized by reduced nephron number (more than would be expected by loss of one kidney), early kidney/glomerular hypertrophy, and progressive renal injury, which culminates in reduced renal function. Long-term studies of temporal relationships among BP, renal hemodynamics, and renal function demonstrate that spontaneous single-kidney HSRA rats are more likely than uninephrectomized normal littermates to exhibit renal impairment because of the combination of reduced nephron numbers and prolonged exposure to renal compensatory mechanisms (i.e., hyperfiltration). Future studies with this novel animal model may provide additional insight into the genetic contributions to kidney development and agenesis and the factors influencing susceptibility to renal injury in individuals with congenital solitary kidney. PMID:25349207

Nephron Deficiency and Predisposition to Renal Injury in a Novel One-Kidney Genetic Model.

PubMed

Wang, Xuexiang; Johnson, Ashley C; Williams, Jan M; White, Tiffani; Chade, Alejandro R; Zhang, Jie; Liu, Ruisheng; Roman, Richard J; Lee, Jonathan W; Kyle, Patrick B; Solberg-Woods, Leah; Garrett, Michael R

2015-07-01

Some studies have reported up to 40% of patients born with a single kidney develop hypertension, proteinuria, and in some cases renal failure. The increased susceptibility to renal injury may be due, in part, to reduced nephron numbers. Notably, children who undergo nephrectomy or adults who serve as kidney donors exhibit little difference in renal function compared with persons who have two kidneys. However, the difference in risk between being born with a single kidney versus being born with two kidneys and then undergoing nephrectomy are unclear. Animal models used previously to investigate this question are not ideal because they require invasive methods to model congenital solitary kidney. In this study, we describe a new genetic animal model, the heterogeneous stock-derived model of unilateral renal agenesis (HSRA) rat, which demonstrates 50%-75% spontaneous incidence of a single kidney. The HSRA model is characterized by reduced nephron number (more than would be expected by loss of one kidney), early kidney/glomerular hypertrophy, and progressive renal injury, which culminates in reduced renal function. Long-term studies of temporal relationships among BP, renal hemodynamics, and renal function demonstrate that spontaneous single-kidney HSRA rats are more likely than uninephrectomized normal littermates to exhibit renal impairment because of the combination of reduced nephron numbers and prolonged exposure to renal compensatory mechanisms (i.e., hyperfiltration). Future studies with this novel animal model may provide additional insight into the genetic contributions to kidney development and agenesis and the factors influencing susceptibility to renal injury in individuals with congenital solitary kidney. Copyright © 2015 by the American Society of Nephrology.

Ansys Fluent versus Sim Vascular for 4-D patient-specific computational hemodynamics in renal arteries

NASA Astrophysics Data System (ADS)

Mumbaraddi, Avinash; Yu, Huidan (Whitney); Sawchuk, Alan; Dalsing, Michael

2015-11-01

The objective of this clinical-need driven research is to investigate the effect of renal artery stenosis (RAS) on the blood flow and wall shear stress in renal arteries through 4-D patient-specific computational hemodynamics (PSCH) and search for possible critical RASs that significantly alter the pressure gradient across the stenosis by manually varying the size of RAS from 50% to 95%. The identification of the critical RAS is important to understand the contribution of RAS to the overall renal resistance thus appropriate clinical therapy can be determined in order to reduce the hypertension. Clinical CT angiographic data together with Doppler Ultra sound images of an anonymous patient are used serving as the required inputs of the PSCH. To validate the PSCH, we use both Ansys Fluent and Sim Vascular and compare velocity, pressure, and wall-shear stress under identical conditions. Renal Imaging Technology Development Program (RITDP) Grant.

Recombinant erythropoietin acutely decreases renal perfusion and decouples the renin-angiotensin-aldosterone system.

PubMed

Aachmann-Andersen, Niels J; Christensen, Soren J; Lisbjerg, Kristian; Oturai, Peter; Johansson, Pär I; Holstein-Rathlou, Niels-Henrik; Olsen, Niels V

2018-03-01

The effect of recombinant erythropoietin (rhEPO) on renal and systemic hemodynamics was evaluated in a randomized double-blinded, cross-over study. Sixteen healthy subjects were tested with placebo, or low-dose rhEPO for 2 weeks, or high-dose rhEPO for 3 days. Subjects refrained from excessive salt intake, according to instructions from a dietitian. Renal clearance studies were done for measurements of renal plasma flow, glomerular filtration rate (GFR) and the segmentel tubular handling of sodium and water (lithium clearance). rhEPO increased arterial blood pressure, total peripheral resistance, and renal vascular resistance, and decreased renal plasma flow in the high-dose rhEPO intervention and tended to decrease GFR. In spite of the decrease in renal perfusion, rhEPO tended to decrease reabsorption of sodium and water in the proximal tubule and induced a prompt decrease in circulating levels of renin and aldosterone, independent of changes in red blood cell mass, blood volumes, and blood pressure. We also found changes in biomarkers showing evidence that rhEPO induced a prothrombotic state. Our results suggest that rhEPO causes a direct downregulation in proximal tubular reabsorption that seems to decouple the activity of the renin-angiotensin-aldosterone system from changes in renal hemodynamics. This may serve as a negative feed-back mechanism on endogenous synthesis of EPO when circulating levels of EPO are high. These results demonstrates for the first time in humans a direct effect of rhEPO on renal hemodynamics and a decoupling of the renin-angiotensin-aldosterone system. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Quantification of single-kidney glomerular filtration rate with electron-beam computed tomography

NASA Astrophysics Data System (ADS)

Lerman, Lilach O.; Ritman, Erik L.; Pelaez, Laura I.; Sheedy, Patrick F., II; Krier, James D.

2000-04-01

The ability to accurately and noninvasively quantify single- kidney GFR could be invaluable for assessment of renal function. We developed a model that enables this measurement with EBCT. To examine the reliability of this method, EBCT renal flow and volume studies after contrast media administration were performed in pigs with unilateral renal artery stenosis (Group 1), controls (Group 2), and simultaneously with inulin clearance (Group 3). Renal flow curves, obtained from the bilateral renal cortex and medulla, depicted transit of the contrast through the vascular and tubular compartments, and were fitted using extended gamma- variate functions. Renal blood flow was calculated as the sum of products of cortical and medullary perfusions and volumes. Normalized GFR (mL/min/cc) was calculated using the rate (maximal slope) of proximal tubular contrast accumulation, and EBCT-GFR as normalized GFR* cortical volume. In Group 1, the decreased GFR of the stenotic kidney correlated well with its decreased volume and RBF, and with the degree of stenosis (r equals -0.99). In Group 3, EBCT-GFR correlated well with inulin clearance (slope 1.1, r equals 0.81). This novel approach can be very useful for quantification of concurrent regional hemodynamics and function in the intact kidneys, in a manner potentially applicable to humans.

Disparate effects of single endothelin A and B receptor blocker therapy on the progression of renal injury in advanced renovascular disease

PubMed Central

Chade, Alejandro R.; Stewart, Nicholas J.; Peavy, Patrick R.

2013-01-01

We hypothesized that chronic specific endothelin (ET)-A receptor blockade therapy would reverse renal dysfunction and injury in advanced experimental renovascular disease. To test this, unilateral renovascular disease was induced in 19 pigs and after 6 weeks, single-kidney hemodynamics and function was quantified in vivo using computed-tomography. All pigs with renovascular disease were divided such that 7 were untreated, 7 were treated with ET-A blockers, and 5 were treated with ET-B blockers. Four weeks later, all pigs were re-studied in vivo, then euthanized and ex vivo studies performed on the stenotic kidney to quantify microvascular density, remodeling, renal oxidative stress, inflammation, and fibrosis. RBF, GFR, and redox status were significantly improved in the stenotic kidney after ET-A but not ET-B blockade. Furthermore, only ET-A blockade therapy reversed renal microvascular rarefaction and diminished remodeling, which was accompanied by a marked decreased in renal inflammatory and fibrogenic activity. Thus, ET-A but not ET-B blockade ameliorated renal injury in pigs with advanced renovascular disease by stimulating microvascular proliferation and decreasing the progression of microvascular remodeling, renal inflammation and fibrosis in the stenotic kidney. These effects were functionally consequential since ET-A blockade improved single kidney microvascular endothelial function, RBF, and GFR, and decreased albuminuria. PMID:24352153

eNOS gene Glu298Asp and 4b/a polymorphisms are associated with renal function parameters in Mexican patients with Fabry disease.

PubMed

Marin-Medina, A; Brambila-Tapia, A J L; Picos-Cárdenas, V J; Gallegos-Arreola, M P; Figuera, L E

2016-10-24

Fabry disease (FD) is an inherited X-linked lysosomal disease that causes renal failure in a high percentage of affected individuals. The eNOS gene encodes for endothelial nitric oxide synthase, which plays an important role in glomerular hemodynamics. This gene has two main polymorphisms (Glu298Asp and 4b/a) that have been studied in the context of many different diseases, including those involving cardiovascular and renal alterations. Considering the lack of information regarding eNOS variants and FD, we investigated whether there were associations between eNOS genetic variants and renal function parameters in Mexican patients with FD and renal impairment. In total, 15 FD patients with renal alterations were included in the present study, and associations between eNOS polymorphisms and renal function parameters (urea, creatinine, and GFR) were evaluated. The Asp298 and 4a alleles of the eNOS gene were found to be significantly associated with increased levels of urea and creatinine, and a decreased glomerular filtration rate in FD patients, and this association behaved in a co-dominant fashion. Our results coincide with previous reports showing an association between these polymorphisms and kidney disease, and along with other studies regarding their role in the nitric oxide pathway, suggest that these variants affect the severity of nephropathy in patients with FD.

Acetylcysteine reduces plasma homocysteine concentration and improves pulse pressure and endothelial function in patients with end-stage renal failure.

PubMed

Scholze, Alexandra; Rinder, Christiane; Beige, Joachim; Riezler, Reiner; Zidek, Walter; Tepel, Martin

2004-01-27

Increased oxidative stress, elevated plasma homocysteine concentration, increased pulse pressure, and impaired endothelial function constitute risk factors for increased mortality in patients with end-stage renal failure. We investigated the metabolic and hemodynamic effects of intravenous administration of acetylcysteine, a thiol-containing antioxidant, during a hemodialysis session in a prospective, randomized, placebo-controlled crossover study in 20 patients with end-stage renal failure. Under control conditions, a hemodialysis session reduced plasma homocysteine concentration to 58+/-22% predialysis (mean+/-SD), whereas in the presence of acetylcysteine, the plasma homocysteine concentration was significantly more reduced to 12+/-7% predialysis (P<0.01). The reduction of plasma homocysteine concentration was significantly correlated with a reduction of pulse pressure. A 10% decrease in plasma homocysteine concentration was associated with a decrease of pulse pressure by 2.5 mm Hg. Analysis of the second derivative of photoplethysmogram waveform showed changes of arterial wave reflectance during hemodialysis in the presence of acetylcysteine, indicating improved endothelial function. Acetylcysteine-dependent increase of homocysteine removal during a hemodialysis session improves plasma homocysteine concentration, pulse pressure, and endothelial function in patients with end-stage renal failure.

Role of Mas receptor antagonist (A779) in renal hemodynamics in condition of blocked angiotensin II receptors in rats.

PubMed

Mansoori, A; Oryan, S; Nematbakhsh, M

2016-03-01

The vasodilatory effect of angiotensin 1-7 (Ang 1-7) is exerted in the vascular bed via Mas receptor (MasR) gender dependently. However, the crosstalk between MasR and angiotensin II (Ang II) types 1 and 2 receptors (AT1R and AT2R) may change some actions of Ang 1-7 in renal circulation. In this study by blocking AT1R and AT2R, the role of MasR in kidney hemodynamics was described. In anaesthetized male and female Wistar rats, the effects of saline as vehicle and MasR blockade (A779) were tested on mean arterial pressure (MAP), renal perfusion pressure (RPP), renal blood flow (RBF), and renal vascular resistance (RVR) when both AT1R and AT2R were blocked by losartan and PD123319, respectively. In male rats, when AT1R and AT2R were blocked, there was a tendency for the increase in RBF/wet kidney tissue weight (RBF/KW) to be elevated by A779 as compared with the vehicle (P=0.08), and this was not the case in female rats. The impact of MasR on renal hemodynamics appears not to be sexual dimorphism either when Ang II receptors were blocked. It seems that co-blockade of all AT1R, AT2R, and MasR may alter RBF/ KW in male more than in female rats. These findings support a crosstalk between MasR and Ang II receptors in renal circulation.

Reversibility of the Effects of Aliskiren in the Renal Versus Systemic Circulation

PubMed Central

Schneider, Markus P.; Janka, Rolf; Ziegler, Thomas; Raff, Ulrike; Ritt, Martin; Ott, Christian; Veelken, Roland; Uder, Michael; Schmieder, Roland E.

2012-01-01

Summary Background and objectives Renal hemodynamic effects of inhibitors of the renin-angiotensin system can increase the risk of acute kidney injury under certain conditions. The BP-lowering effects of the renin inhibitor aliskiren are sustained 3–4 weeks after withdrawal. In this study, the reversibility of the renal hemodynamic effects of aliskiren was tested. Design, setting, participants, & measurements In this open-label study, renal perfusion was measured by 1.5-T magnetic resonance imaging–arterial spin labeling in 34 subjects with arterial hypertension before aliskiren (pre-aliskiren), after 4 weeks of aliskiren treatment (300 mg), and 4–5 days (∼2.5–3.0× plasma half-life) after withdrawal (post-aliskiren). Results Aliskiren reduced systolic BP from 152 ± 14 to 139 ± 16 mmHg (P<0.0001), which was sustained post-aliskiren (136 ± 13 mmHg, P=1.00 versus aliskiren). Aliskiren significantly altered renal perfusion (P=0.005), increasing from 272 ± 25 pre-aliskiren to 287 ± 29 ml/min per 100 g during aliskiren (P=0.03). This increase in renal perfusion was completely reversed post-aliskiren (272 ± 26 ml/min per 100 g, P=0.03 versus aliskiren, P=0.63 versus pre-aliskiren). No changes were noted in urinary angiotensinogen levels. Plasma renin activity was reduced by aliskiren, which was sustained post-aliskiren. Angiotensin II and aldosterone were reduced by aliskiren but recovered post-aliskiren to pre-aliskiren levels. Conclusions After withdrawal of aliskiren, the effects on BP were sustained, whereas increase in renal perfusion was reversed, which was associated with recovery of angiotensin II and aldosterone to pretreatment levels. Renal hemodynamic effects are more readily reversible than systemic effects of aliskiren. PMID:22173856

Hemoadsorption in a Case of Severe Septic Shock and Necrotizing Fasciitis Caused by Nontraumatic Renal Rupture due to Pyelonephritis with Obstructive Uropathy.

PubMed

Kousoulas, Lampros; Wittel, Uwe; Fichtner-Feigl, Stefan; Utzolino, Stefan

2018-01-01

Nontraumatic renal rupture due to pyelonephritis with obstructive uropathy is an uncommon but life-threatening situation. A 25-year-old female presented to the emergency department with acute worsening of abdominal pain that began four weeks earlier. She was found to have peritonitis, leukocytosis, severe lactic acidosis, and a pronounced anemia and imaging was consistent with nontraumatic renal rupture with retroperitoneal abscess, perforation of the colon, and severe necrotizing fasciitis of the right lower limb. She underwent a right nephrectomy, a right hemicolectomy, surgical debridement of the retroperitoneum, and an upper thigh amputation. Due to severe septic shock and rhabdomyolysis with acute renal failure we performed a combined treatment of hemoadsorption using a Cytosorb hemoadsorber and continuous venovenous hemodialysis (CVVHD). Subsequently the patient recovered and was discharged home with no signs of infections and with normal renal function. We present a case of pyelonephritis with nontraumatic renal rupture leading to necrotizing fasciitis with osteomyelitis of the lower limb. The early treatment of the patient with a Cytosorb hemoadsorber led to a rapid hemodynamic and metabolic stabilization and preservation of the renal function, suggesting that hemoadsorption might be a rescue therapy in patients with severe septic shock and traumatic rhabdomyolysis.

Hemoadsorption in a Case of Severe Septic Shock and Necrotizing Fasciitis Caused by Nontraumatic Renal Rupture due to Pyelonephritis with Obstructive Uropathy

PubMed Central

Wittel, Uwe; Fichtner-Feigl, Stefan; Utzolino, Stefan

2018-01-01

Background Nontraumatic renal rupture due to pyelonephritis with obstructive uropathy is an uncommon but life-threatening situation. Case Presentation A 25-year-old female presented to the emergency department with acute worsening of abdominal pain that began four weeks earlier. She was found to have peritonitis, leukocytosis, severe lactic acidosis, and a pronounced anemia and imaging was consistent with nontraumatic renal rupture with retroperitoneal abscess, perforation of the colon, and severe necrotizing fasciitis of the right lower limb. She underwent a right nephrectomy, a right hemicolectomy, surgical debridement of the retroperitoneum, and an upper thigh amputation. Due to severe septic shock and rhabdomyolysis with acute renal failure we performed a combined treatment of hemoadsorption using a Cytosorb hemoadsorber and continuous venovenous hemodialysis (CVVHD). Subsequently the patient recovered and was discharged home with no signs of infections and with normal renal function. Conclusion We present a case of pyelonephritis with nontraumatic renal rupture leading to necrotizing fasciitis with osteomyelitis of the lower limb. The early treatment of the patient with a Cytosorb hemoadsorber led to a rapid hemodynamic and metabolic stabilization and preservation of the renal function, suggesting that hemoadsorption might be a rescue therapy in patients with severe septic shock and traumatic rhabdomyolysis. PMID:29854478

Clinical value of natriuretic peptides in chronic kidney disease.

PubMed

Santos-Araújo, Carla; Leite-Moreira, Adelino; Pestana, Manuel

2015-01-01

According to several lines of evidence, natriuretic peptides (NP) are the main components of a cardiac-renal axis that operate in clinical conditions of decreased cardiac hemodynamic tolerance to regulate sodium homeostasis, blood pressure and vascular function. Even though it is reasonable to assume that NP may exert a relevant role in the adaptive response to renal mass ablation, evidence gathered so far suggest that this contribution is probably complex and dependent on the type and degree of the functional mass loss. In the last years NP have been increasingly used to diagnose, monitor treatment and define the prognosis of several cardiovascular (CV) diseases. However, in many clinical settings, like chronic kidney disease (CKD), the predictive value of these biomarkers has been questioned. In fact, it is now well established that renal function significantly affects the plasmatic levels of NP and that renal failure is the clinical condition associated with the highest plasmatic levels of these peptides. The complexity of the relation between NP plasmatic levels and CV and renal functions has obvious consequences, as it may limit the predictive value of NP in CV assessment of CKD patients and be a demanding exercise for clinicians involved in the daily management of these patients. This review describes the role of NP in the regulatory response to renal function loss and addresses the main factors involved in the clinical valorization of the peptides in the context of significant renal failure. Copyright © 2015 The Authors. Published by Elsevier España, S.L.U. All rights reserved.

Renal Heme Oxygenase-1 Induction with Hemin Augments Renal Hemodynamics, Renal Autoregulation, and Excretory Function

PubMed Central

Botros, Fady T.; Dobrowolski, Leszek; Navar, L. Gabriel

2012-01-01

Heme oxygenases (HO-1; HO-2) catalyze conversion of heme to free iron, carbon monoxide, and biliverdin/bilirubin. To determine the effects of renal HO-1 induction on blood pressure and renal function, normal control rats (n = 7) and hemin-treated rats (n = 6) were studied. Renal clearance studies were performed on anesthetized rats to assess renal function; renal blood flow (RBF) was measured using a transonic flow probe placed around the left renal artery. Hemin treatment significantly induced renal HO-1. Mean arterial pressure and heart rate were not different (115 ± 5 mmHg versus 112 ± 4 mmHg and 331 ± 16 versus 346 ± 10 bpm). However, RBF was significantly higher (9.1 ± 0.8 versus 7.0 ± 0.5 mL/min/g, P < 0.05), and renal vascular resistance was significantly lower (13.0 ± 0.9 versus 16.6 ± 1.4 [mmHg/(mL/min/g)], P < 0.05). Likewise, glomerular filtration rate was significantly elevated (1.4 ± 0.2 versus 1.0 ± 0.1 mL/min/g, P < 0.05), and urine flow and sodium excretion were also higher (18.9 ± 3.9 versus 8.2 ± 1.0 μL/min/g, P < 0.05 and 1.9 ± 0.6 versus 0.2 ± 0.1 μmol/min/g, P < 0.05, resp.). The plateau of the autoregulation relationship was elevated, and renal vascular responses to acute angiotensin II infusion were attenuated in hemin-treated rats reflecting the vasodilatory effect of HO-1 induction. We conclude that renal HO-1 induction augments renal function which may contribute to the antihypertensive effects of HO-1 induction observed in hypertension models. PMID:22518281

Role of the Sympathetic Nervous System and Its Modulation in Renal Hypertension

PubMed Central

Sata, Yusuke; Head, Geoffrey A.; Denton, Kate; May, Clive N.; Schlaich, Markus P.

2018-01-01

The kidneys are densely innervated with renal efferent and afferent nerves to communicate with the central nervous system. Innervation of major structural components of the kidneys, such as blood vessels, tubules, the pelvis, and glomeruli, forms a bidirectional neural network to relay sensory and sympathetic signals to and from the brain. Renal efferent nerves regulate renal blood flow, glomerular filtration rate, tubular reabsorption of sodium and water, as well as release of renin and prostaglandins, all of which contribute to cardiovascular and renal regulation. Renal afferent nerves complete the feedback loop via central autonomic nuclei where the signals are integrated and modulate central sympathetic outflow; thus both types of nerves form integral parts of the self-regulated renorenal reflex loop. Renal sympathetic nerve activity (RSNA) is commonly increased in pathophysiological conditions such as hypertension and chronic- and end-stage renal disease. Increased RSNA raises blood pressure and can contribute to the deterioration of renal function. Attempts have been made to eliminate or interfere with this important link between the brain and the kidneys as a neuromodulatory treatment for these conditions. Catheter-based renal sympathetic denervation has been successfully applied in patients with resistant hypertension and was associated with significant falls in blood pressure and renal protection in most studies performed. The focus of this review is the neural contribution to the control of renal and cardiovascular hemodynamics and renal function in the setting of hypertension and chronic kidney disease, as well as the specific roles of renal efferent and afferent nerves in this scenario and their utility as a therapeutic target. PMID:29651418

Role of the Sympathetic Nervous System and Its Modulation in Renal Hypertension.

PubMed

Sata, Yusuke; Head, Geoffrey A; Denton, Kate; May, Clive N; Schlaich, Markus P

2018-01-01

The kidneys are densely innervated with renal efferent and afferent nerves to communicate with the central nervous system. Innervation of major structural components of the kidneys, such as blood vessels, tubules, the pelvis, and glomeruli, forms a bidirectional neural network to relay sensory and sympathetic signals to and from the brain. Renal efferent nerves regulate renal blood flow, glomerular filtration rate, tubular reabsorption of sodium and water, as well as release of renin and prostaglandins, all of which contribute to cardiovascular and renal regulation. Renal afferent nerves complete the feedback loop via central autonomic nuclei where the signals are integrated and modulate central sympathetic outflow; thus both types of nerves form integral parts of the self-regulated renorenal reflex loop. Renal sympathetic nerve activity (RSNA) is commonly increased in pathophysiological conditions such as hypertension and chronic- and end-stage renal disease. Increased RSNA raises blood pressure and can contribute to the deterioration of renal function. Attempts have been made to eliminate or interfere with this important link between the brain and the kidneys as a neuromodulatory treatment for these conditions. Catheter-based renal sympathetic denervation has been successfully applied in patients with resistant hypertension and was associated with significant falls in blood pressure and renal protection in most studies performed. The focus of this review is the neural contribution to the control of renal and cardiovascular hemodynamics and renal function in the setting of hypertension and chronic kidney disease, as well as the specific roles of renal efferent and afferent nerves in this scenario and their utility as a therapeutic target.

Intensity of Renal Support in Critically Ill Patients with Acute Kidney Injury

PubMed Central

2008-01-01

BACKGROUND The optimal intensity of renal-replacement therapy in critically ill patients with acute kidney injury is controversial. METHODS We randomly assigned critically ill patients with acute kidney injury and failure of at least one nonrenal organ or sepsis to receive intensive or less intensive renal-replacement therapy. The primary end point was death from any cause by day 60. In both study groups, hemodynamically stable patients underwent intermittent hemodialysis, and hemodynamically unstable patients underwent continuous venovenous hemodiafiltration or sustained low-efficiency dialysis. Patients receiving the intensive treatment strategy underwent intermittent hemodialysis and sustained low-efficiency dialysis six times per week and continuous venovenous hemodiafiltration at 35 ml per kilogram of body weight per hour; for patients receiving the less-intensive treatment strategy, the corresponding treatments were provided thrice weekly and at 20 ml per kilogram per hour. RESULTS Baseline characteristics of the 1124 patients in the two groups were similar. The rate of death from any cause by day 60 was 53.6% with intensive therapy and 51.5% with less-intensive therapy (odds ratio, 1.09; 95% confidence interval, 0.86 to 1.40; P = 0.47). There was no significant difference between the two groups in the duration of renalreplacement therapy or the rate of recovery of kidney function or nonrenal organ failure. Hypotension during intermittent dialysis occurred in more patients randomly assigned to receive intensive therapy, although the frequency of hemodialysis sessions complicated by hypotension was similar in the two groups. CONCLUSIONS Intensive renal support in critically ill patients with acute kidney injury did not decrease mortality, improve recovery of kidney function, or reduce the rate of nonrenal organ failure as compared with less-intensive therapy involving a defined dose of intermittent hemodialysis three times per week and continuous renal-replacement therapy at 20 ml per kilogram per hour. (ClinicalTrials.gov number, NCT00076219.) PMID:18492867

[Preclinical diagnostics and correction of the disturbed renal blood flow in the children presenting with diabetic nephropathy].

PubMed

Aver'ianov, A P; Tkacheva, E N; Bolotova, N V; Filina, N Iu; Ivanova, Iu V; Nikolaeva, N V; Tikhonova, L A

2011-01-01

The present study included 86 children aged between 7 and 17 years with type 1 diabetes mellitus from 1 to 15 years in duration. In all the patients, renal blood flow was investigated with the use of ultrasonic dopplerography. The results of the study suggest disturbances of intrarenal hemodynamics that manifested themselves as enhanced resistance of renal arteries from periphery to the centre in the patients at the hyperfiltration stage of diabetic nephropathy (DN) in conjunction with the reduced velocity of blood flow in inter-lobular and segmental arteries. In contrast, the patients at the microalbuminuric stage of diabetic nephropathy exhibited increased resistance and reduced velocity of blood flow in the main renal veins. In 35 patients presenting with diabetic nephropathy, hemodynamic correction was achieved by the application of the traveling pulsed magnetic field (TP-MF) to the renal region using an AMO-ATOS-E apparatus (Russia). This treatment resulted in normalization of the characteristics of renal blood flow. It is concluded that TPMF has good prospects for the use as a component of the combined treatment of diabetic nephropathy.

Dietary Sodium Modulation of Aldosterone Activation and Renal Function During the Progression of Experimental Heart Failure Miller: Dietary Sodium and Early Heart Failure

PubMed Central

Miller, Wayne L.; Borgeson, Daniel D.; Grantham, J. Aaron; Luchner, Andreas; Redfield, Margaret M.; Burnett, John C.

2015-01-01

Aims Aldosterone activation is central to the sodium-fluid retention that marks the progression of heart failure (HF). The actions of dietary sodium restriction, a mainstay in HF management, on cardiorenal and neuroendocrine adaptations during the progression of HF are poorly understood. The study aim was to assess the role of dietary sodium during the progression of experimental HF. Methods and Results Experimental HF was produced in a canine model by rapid right ventricular pacing which evolves from early mild HF to overt, severe HF. Dogs were fed one of three diets: 1) high sodium [250 mEq (5.8 grams) per day, n=6]; 2) standard sodium [58 mEq (1.3 grams) per day, n=6]; and 3) sodium restriction [11 mEq (0.25 grams) per day, n=6]. During the 38 day study hemodynamics, renal function, renin activity (PRA), and aldosterone were measured. Changes in hemodynamics at 38 days were similar in all three groups, as were changes in renal function. Aldosterone activation was demonstrated in all three groups, however, dietary sodium restriction, in contrast to high sodium, resulted in early (10 days) activation of PRA and aldosterone. High sodium demonstrated significant suppression of aldosterone activation over the course of HF progression. Conclusions Excessive dietary sodium restriction particularly in early stage HF results in early aldosterone activation, while normal and excess sodium intake are associated with delayed or suppressed activation. These findings warrant evaluation in humans to determine if dietary sodium manipulation, particularly during early stage HF, may have a significant impact on neuroendocrine disease progression. PMID:25823360

Atherosclerotic renovascular disease among hypertensive adults

PubMed Central

Davis, Ross P.; Pearce, Jeffrey D.; Craven, Timothy E.; Moore, Phillip S.; Edwards, Matthew S.; Godshall, Christopher J.; Hansen, Kimberley J.

2010-01-01

Purpose Ths report describes the change in atherosclerotic renovascular disease (AS-RVD) among hypertensive adults referred for renal duplex sonography (RDS) scan. Methods From Oct 1993 through July 2008, 20,994 patients had RDS at our center. A total of 434 hypertensive patients with two or more RDS exams without intervention comprised the study cohort. Patient demographics (blood pressures, medications, serum creatinine levels, and data from RDS) were collected. Analyses of longitudinal changes in Doppler scan parameters, blood pressures, and renal function were performed by fitting linear growth-curve models. After confirming the linearity of change in Doppler scan parameters among patients with variable number of studies, estimates of mean slopes were calculated using maximum likelihood techniques. For changes in renal function, quadratic growth curves were required to describe longitudinal change. Results A total of 434 subjects (212 men [49%] and 222 women [51%]; mean age, 64.6 ± 12.2 years) provided 1351 studies (mean, 3.2 ± 2.4; range, 2 to 18) for 863 kidneys over a mean follow-up of 34.4 ± 25.1 months. At baseline, 20.6% of kidneys demonstrated hemodynamically significant stenosis. On follow-up, 72 kidneys (9.1%) demonstrated anatomic progression of disease. A total of 54 kidneys (6.9%) progressed to significant stenosis and 18 (2.3%) progressed to occlusion. Controlling for progression of disease, baseline renal artery status demonstrated a strong association with baseline kidney length (P = .0006). Significant annualized change in renal length was observed (cm change/year ± standard error of the mean [SEM]: 0.042 ± 0.011; P = .0002) among both kidneys with and without critical disease at baseline, however, decline in length was significantly greater among kidneys exhibiting progression of renovascular disease (−0.152 ± 0.028 cm/year; comparison of slopes between groups P = .0005). In the absence of progression, the presence or absence of critical renal artery stenosis at baseline did not affect the rate of decline in renal length. Fitted models for the natural log transform of serum creatinine demonstrated a significant increase during follow-up (P < .0001). No association was observed between change in serum creatinine and baseline renovascular disease status, or its progression. Conclusion A total of 32% of hypertensive adults referred for RDS demonstrated hemodynamically significant renal artery stenosis. Regardless of the presence or absence of baseline disease, a small percentage of patients demonstrated anatomic progression of AS-RVD. A total of 9.1% demonstrated anatomic progression and 2.3% progressed to occlusion. Although anatomic progression of AS-RVD was associated with an increased rate of decline in renal length, progression did not predict a decline in excretory renal function. Intervention for AS-RVD should be selective and reserved for strict indications. PMID:19700093

Renal Hemodynamics and Ammoniagenesis

PubMed Central

Lemieux, Guy; Vinay, Patrick; Cartier, Pierre

1974-01-01

Renal production of ammonia by the left kidney was studied in 31 acidotic dogs (NH4Cl) after acute constriction of the renal artery. Renal ammoniagenesis fell in direct proportion with the reduction in glomerular filtration rate and renal plasma flow. The renal extraction of glutamine by the experimental kidney fell in direct proportion with the reduction in renal hemodynamics. Extracted glutamine remained greater than filtered glutamine indicating that both the luminal and antiluminal transport sites were operative. The relationship between renal extraction of glutamine and ammoniagenesis observed during control was maintained after renal artery constriction (1.7 μmol NH3 produced for each μmol of glutamine extracted). Systemic venous or renal intra-arterial infusion of glutamine during arterial constriction increased renal production of ammonia to or above control values. These observations indicate that the mechanisms responsible for glutamine extraction and ammonia production were operating normally despite reduced hemodynamics. When measured immediately after arterial clamping, the renal venous pNH3 was found to rise significantly decreasing progressively thereafter towards control values. The extracted fraction of total glutamine delivered to the kidney (31%) did not change after acute reduction of the glutamine load. Thus, the antiluminal extraction site was incapable of lowering renal venous plasma glutamine concentration below 0.33 μM/ml. In a second series of experiments, the properties of the antiluminal site of transport for glutamine were studied after complete occlusion of the left ureter in acidotic and nonacidotic animals. Under these circumstances, it was demonstrated that the antiluminal site is capable of extracting sufficient glutamine to maintain total ammonia production at 60% or more of control. In acidotic animals, changes in cellular pNH3 appeared to play a key role on the antiluminal extraction of glutamine since the significant rise in renal blood flow often observed after ureteral occlusion prevented the rise in pNH3 noted when blood flow remained constant. Thus, when renal blood flow rose glutamine extraction and ammonia production were maintained at control values. In these acidotic animals, glutamine infusion failed to influence ammonia production until luminal transport was restored by release of ureteral clamp and resumption of glomerular filtration. The latter observation establishes that reabsorbed glutamine is utilized at least in part for ammonia production. PMID:4812445

Effect of microgravity on renal and femoral flows during LBNP & intravenous saline load

NASA Technical Reports Server (NTRS)

Arbeille, P.; Gaffney, F. A.; Beck, L.; Coulon, J.; Porcher, M.; Blomqvist, C. G.

1996-01-01

Renal and femoral hemodynamics were studied in crew members at rest and during lower body negative pressure before and after the D-2 Spacelab mission and with intravenous saline loading. Specific measurements included renal vascular resistance, femoral arterial flow, and vascular resistance, along with other cardiovascular parameters. Cardiovascular adaptation to microgravity is discussed with a focus on changes observed in femoral and renal vascular resistance.

Doppler indexes of left ventricular systolic and diastolic flow and central pulse pressure in relation to renal resistive index.

PubMed

Kuznetsova, Tatiana; Cauwenberghs, Nicholas; Knez, Judita; Thijs, Lutgarde; Liu, Yan-Ping; Gu, Yu-Mei; Staessen, Jan A

2015-04-01

The cardio-renal interaction occurs via hemodynamic and humoral factors. Noninvasive assessment of renal hemodynamics is currently possible by assessment of renal resistive index (RRI) derived from intrarenal Doppler arterial waveforms as ((peak systolic velocity - end-diastolic velocity)/peak systolic velocity). Limited information is available regarding the relationship between RRI and cardiac hemodynamics. We investigated these associations in randomly recruited subjects from a general population. In 171 participants (48.5% women; mean age, 52.2 years), using pulsed wave Doppler, we measured RRI (mean, 0.60) and left ventricular outflow tract (LVOT) and transmitral (E and A) blood flow peak velocities and its velocity time integrals (VTI). Using carotid applanation tonometry, we measured central pulse pressure and arterial stiffness indexes such as augmentation pressure and carotid-femoral pulse wave velocity. In stepwise regression analysis, RRI independently and significantly increased with female sex, age, body weight, brachial pulse pressure, and use of β-blockers, whereas it decreased with body height and mean arterial pressure. In multivariable-adjusted models with central pulse pressure and arterial stiffness indexes as the explanatory variables, we observed a significant and positive correlation of RRI only with central pulse pressure (P < 0.0001). Among the Doppler indexes of left ventricular blood flow, RRI was significantly and positively associated with LVOT and E peak velocities (P ≤ 0.012) and VTIs (P ≤ 0.010). We demonstrated that in unselected subjects RRI was significantly associated with central pulse pressure and left ventricular systolic and diastolic Doppler blood flow indexes. Our findings imply that in addition to the anthropometric characteristics, cardiac hemodynamic factors influence the intrarenal arterial Doppler waveform patterns. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The use of renal replacement therapy in acute decompensated heart failure.

PubMed

Udani, Suneel M; Murray, Patrick T

2009-01-01

The worsening of renal function in the context of decompensated heart failure is an increasingly common clinical scenario, dubbed the cardiorenal syndrome. Its development is not completely understood; however, it results from the hemodynamic and neurohumoral alterations that occur in the setting of left ventricular pressure and volume overload with poor cardiac output. Diuretics have been the mainstay of treatment; however, they are often unsuccessful in reversing the vicious cycle of volume overload, worsening cardiac function, and azotemia. Renal replacement therapy (RRT) in the form of isolated or continuous ultrafiltration (UF) with or without a component of solute clearance (hemofiltration or hemodialysis) has been increasingly utilized as a therapeutic tool in this setting. Initial clinical trial data on the use of UF have demonstrated promising cardiac outcomes with regard to fluid removal and symptom relief without worsening renal function. The addition of a component of solute clearance may provide additional benefits in these patients with varying degrees of renal impairment. The exact clinical setting in which the various forms of RRT should be applied as initial or early therapy for acute decompensated heart failure (ADHF) remains unknown. More research examining the use of RRT in ADHF is necessary; however, it appears that the patients with the most severe clinical presentations have the best chance of benefiting from the early application of RRT.

Effects of hypercholesterolemia of renal hemodynamics: study in patients with nephrotic syndrome.

PubMed

Fuiano, G; Esposito, C; Sepe, V; Colucci, G; Bovino, M; Rosa, M; Balletta, M; Bellinghieri, G; Conte, G; Cianciaruso, B; Dal Canton, A

1996-01-01

Experimental and clinical studies have demonstrated a positive relationship between hyperlipidemia and rate of progression of renal disease, suggesting that lipids can induce or aggravate glomerular injury mainly by interacting with mesangial cells. Nevertheless, recently has been demonstrated that increased cholesterol levels can also induce endothelial cell dysfunction. Thus, since endothelium is known to play a major role in modulating the vascular tone, we have tested the possibility that hypercholesterolemia impairs the renal hemodynamics in patients with active nephrotic syndrome and elevated serum cholesterol levels. In this single-blind, nonrandom study, 12 patients were treated with pravastatin (group T, treated, n = 12) and 8 with placebo (group C, controls, n = 8). The controls were studied after the pravastatin group had been completed. Before starting the treatment the patients underwent basal determinations including routine laboratory investigations and PAH and inulin clearances. The same determinations were repeated after 48 h, and 6 and 12 weeks from the beginning of the treatment. The study at 48 h was performed to see if pravastatin had a direct, cholesterol-independent effect on renal function. The following basal results were reported (mean +/- SEM; group T vs. group C): serum cholesterol (mmol/l) 9.7 +/- 0.4 vs. 9.1 +/- 0.3 (NS); proteinuria (g/24 h): 6.2 +/- 0.2 vs. 7.0 +/- 0.7 (NS); PAH clearance (ml/min): 353 +/- 21 vs. 385 +/- 31 (NS); inulin clearance (ml/min): 62.5 +/- 7.7 vs. 67 +/- 9.3 (NS). After 48 h, no changes were observed in both groups. Subsequently, in group T, the following percentage changes of basal levels were observed: serum cholesterol -21.4 +/- 3.2% at 6 weeks (p < 0.05) and -34.9 +/- 3.2% at 12 weeks (p < 0.01); inulin clearance +3 +/- 3.7% at 6 weeks (NS) and +9.3 +/- 2.9% at 12 weeks (p < 0.05); PAH clearance +7 +/- 3.1% at 6 weeks (p < 0.05) and +21.2 +/- 5.5% at 12 weeks (p < 0.01). By contrast, no significant changes of these parameters occurred in group C at any time, so that the percent changes of baseline values of CPAH were significantly greater in group T (at 6 weeks: p < 0.05; at 12 weeks p < 0.005). These results indicate that the reduction of cholesterol is associated with a significant increase in renal plasma flow, thus, suggesting that hypercholesterolemia may actually impair the renal hemodynamics. We speculate that this effect may contribute to increase the risk of ischemic acute renal failure in nephrotic patients and, along with changes induced in the mesangium by other mechanisms, to contribute to the progression of renal disease.

Renal hemodynamic effects of the HMG-CoA reductase inhibitors in autosomal dominant polycystic kidney disease

PubMed Central

Zand, Ladan; Torres, Vicente E.; Larson, Timothy S.; King, Bernard F.; Sethi, Sanjeev; Bergstralh, Eric J.; Angioi, Andrea; Fervenza, Fernando C.

2016-01-01

Background To determine the effect of statins on renal hemodynamics in normal volunteers and those with autosomal dominant polycystic kidney disease either with mild or moderate renal dysfunction. Methods Thirty-two study subjects were enrolled in this study: 11 normal volunteers, 11 study subjects with autosomal dominant polycystic kidney disease (ADPKD) and mild kidney disease and 10 study subjects with ADPKD and moderate kidney disease. Subjects in each group received simvastatin 40 mg once daily for a period of 4 weeks. Renal blood flow was measured based on para-amino-hippurate (PAH) clearance and with the use of a magnetic resonance (MR) scanner at the beginning and following 4 weeks of therapy with statins. Results At the end of the study, except for the lipid profile, which was significantly lower in all groups, other laboratory results showed no change. Four weeks of therapy with simvastatin resulted in no change in serum creatinine, 24-h urinary protein, sodium, iothalamate clearance, PAH clearance or renal blood flow as measured by MRI or based on PAH clearance. Conclusions Four weeks of therapy with simvastatin did not change renal blood flow in the study subjects with ADPKD with mild-to-moderate renal dysfunction or in healthy volunteers. Clinical Trial Registration Number NCT02511418. PMID:26614268

Role of neuropeptide Y in renal sympathetic vasoconstriction: studies in normal and congestive heart failure rats.

PubMed

DiBona, G F; Sawin, L L

2001-08-01

Sympathetic nerve activity, including that in the kidney, is increased in heart failure with increased plasma concentrations of norepinephrine and the vasoconstrictor cotransmitter neuropeptide Y (NPY). We examined the contribution of NPY to sympathetically mediated alterations in kidney function in normal and heart failure rats. Heart failure rats were created by left coronary ligation and myocardial infarction. In anesthetized normal rats, the NPY Y(1) receptor antagonist, H 409/22, at two doses, had no effect on heart rate, arterial pressure, or renal hemodynamic and excretory function. In conscious severe heart failure rats, high-dose H 409/22 decreased mean arterial pressure by 8 +/- 2 mm Hg but had no effect in normal and mild heart failure rats. During graded frequency renal sympathetic nerve stimulation (0 to 10 Hz), high-dose H 409/22 attenuated the decreases in renal blood flow only at 10 Hz (-36% +/- 5%, P <.05) in normal rats but did so at both 4 (-29% +/- 4%, P <.05) and 10 Hz (-33% +/- 5%, P <.05) in heart failure rats. The glomerular filtration rate, urinary flow rate, and sodium excretion responses to renal sympathetic nerve stimulation were not affected by high-dose H 409/22 in either normal or heart failure rats. NPY does not participate in the regulation of kidney function and arterial pressure in normal conscious or anesthetized rats. When sympathetic nervous system activity is increased, as in heart failure and intense renal sympathetic nerve stimulation, respectively, a small contribution of NPY to maintenance of arterial pressure and to sympathetic renal vasoconstrictor responses may be identified.

Influence of deceased donor hemodynamic factors in transplant recipients renal function.

PubMed

Baptista, Ana Paula Maia; Silva, Hélio Tedesco; Pestana, José Osmar Medina

2013-01-01

The incidence of delayed graft function (DGF) and unsatisfactory creatinine clearance (UCC) after renal transplantation is significantly higher in Brazil, when compared with that observed in United States or Europe. Deceased donor (DD) characteristics should directly influence the occurrence of these two outcomes. This study aim to evaluate the influence of DD characteristics on DGF and UCC incidence in Brazil. DD clinical and laboratory variables were correlated with outcome's incidence. We evaluated 787 DD whose organs were transplanted in 1298 patients. We noted a high prevalence of vasoactive drugs use (90.2%), hypernatremia (66.6%) and renal dysfunction (34.8%). The incidence of DGF and UCC was 60.6% and 55.2%, respectively. We observed a progressive increase in DGF risk for age groups over 30 years and for cold ischemia time (CIT) greater than 24 hours. DGF risk was two times higher in recipients of donor kidney final serum creatinine (Cr) over than 1.5 mg/dl. Hypertension and CIT over 36 hours was associated with an increasing of 82% and 99% in UCC risk, respectively. Donor age above 40 years was associated with a progressive increase in UCC risk. DD age, renal function, hypertension and prolonged CIT were associated with increased risk DGF and UCC.

Assessment of Renal Hemodynamics and Oxygenation by Simultaneous Magnetic Resonance Imaging (MRI) and Quantitative Invasive Physiological Measurements.

PubMed

Cantow, Kathleen; Arakelyan, Karen; Seeliger, Erdmann; Niendorf, Thoralf; Pohlmann, Andreas

2016-01-01

In vivo assessment of renal perfusion and oxygenation under (patho)physiological conditions by means of noninvasive diagnostic imaging is conceptually appealing. Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and quantitative parametric mapping of the magnetic resonance (MR) relaxation times T 2* and T 2 are thought to provide surrogates of renal tissue oxygenation. The validity and efficacy of this technique for quantitative characterization of local tissue oxygenation and its changes under different functional conditions have not been systematically examined yet and remain to be established. For this purpose, the development of an integrative multimodality approaches is essential. Here we describe an integrated hybrid approach (MR-PHYSIOL) that combines established quantitative physiological measurements with T 2* (T 2) mapping and MR-based kidney size measurements. Standardized reversible (patho)physiologically relevant interventions, such as brief periods of aortic occlusion, hypoxia, and hyperoxia, are used for detailing the relation between the MR-PHYSIOL parameters, in particular between renal T 2* and tissue oxygenation.

Influence of the renal artery ostium flow diverter on hemodynamics and atherogenesis

PubMed Central

Albert, Scott; Balaban, Robert S.; Neufeld, Edward B.; Rossmann, Jenn Stroud

2014-01-01

The structure and function of the renal artery ostium flow diverter on the caudal side of the renal branch point were previously reported; in this study, we further evaluate the diverter’s possible functions. The protrusion of this structure into the abdominal aorta suggests that the diverter may preferentially direct blood flow to the renal arteries, and that it may also influence flow patterns and recirculation known to be involved in atherogenesis. Three-dimensional computational fluid dynamics (CFD) simulations of steady and pulsatile blood flow are performed to investigate the influence of diverter size and position, and vascular geometry, on the flow patterns and fluid mechanical forces in the neighborhood of the diverter. CFD results show that the flow diverter does affect the blood distribution: depending on the diverter’s position, the flow to the renal arteries may be increased or reduced. Calculated results also demonstrate the diverter’s effect on the Wall Shear Stress (WSS) distribution, and suggest that the diverter contributes to an atherogenic environment in the abdominal aorta, while being atheroprotective in the renal arteries themselves. These results support previous clinical findings, and suggest directions for further clinical study. The results of this work have direct implications in understanding the physiological significance of the diverter, and its potential role in the pathophysiological development of atherosclerosis. PMID:24703300

Influence of the renal artery ostium flow diverter on hemodynamics and atherogenesis.

PubMed

Albert, Scott; Balaban, Robert S; Neufeld, Edward B; Rossmann, Jenn Stroud

2014-05-07

The structure and function of the renal artery ostium flow diverter on the caudal side of the renal branch point were previously reported; in this study, we further evaluate the diverter׳s possible functions. The protrusion of this structure into the abdominal aorta suggests that the diverter may preferentially direct blood flow to the renal arteries, and that it may also influence flow patterns and recirculation known to be involved in atherogenesis. Three-dimensional computational fluid dynamics (CFD) simulations of steady and pulsatile blood flow are performed to investigate the influence of diverter size and position, and vascular geometry, on the flow patterns and fluid mechanical forces in the neighborhood of the diverter. CFD results show that the flow diverter does affect the blood distribution; depending on the diverter׳s position, the flow to the renal arteries may be increased or reduced. Calculated results also demonstrate the diverter׳s effect on the wall shear stress (WSS) distribution, and suggest that the diverter contributes to an atherogenic environment in the abdominal aorta, while being atheroprotective in the renal arteries themselves. These results support previous clinical findings, and suggest directions for further clinical study. The results of this work have direct implications in understanding the physiological significance of the diverter, and its potential role in the pathophysiological development of atherosclerosis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Hemodynamics in Transplant Renal Artery Stenosis and its Alteration after Stent Implantation Based on a Patient-specific Computational Fluid Dynamics Model.

PubMed

Wang, Hong-Yang; Liu, Long-Shan; Cao, Hai-Ming; Li, Jun; Deng, Rong-Hai; Fu, Qian; Zhang, Huan-Xi; Fei, Ji-Guang; Wang, Chang-Xi

Accumulating studies on computational fluid dynamics (CFD) support the involvement of hemodynamic factors in artery stenosis. Based on a patient-specific CFD model, the present study aimed to investigate the hemodynamic characteristics of transplant renal artery stenosis (TRAS) and its alteration after stent treatment. Computed tomography angiography (CTA) data of kidney transplant recipients in a single transplant center from April 2013 to November 2014 were reviewed. The three-dimensional geometry of transplant renal artery (TRA) was reconstructed from the qualified CTA images and categorized into three groups: the normal, stenotic, and stented groups. Hemodynamic parameters including pressure distribution, velocity, wall shear stress (WSS), and mass flow rate (MFR) were extracted. The data of hemodynamic parameters were expressed as median (interquartile range), and Mann-Whitney U-test was used for analysis. Totally, 6 normal, 12 stenotic, and 6 stented TRAs were included in the analysis. TRAS presented nonuniform pressure distribution, adverse pressure gradient across stenosis throat, flow vortex, and a separation zone at downstream stenosis. Stenotic arteries had higher maximal velocity and maximal WSS (2.94 [2.14, 3.30] vs. 1.06 [0.89, 1.15] m/s, 256.5 [149.8, 349.4] vs. 41.7 [37.8, 45.3] Pa at end diastole, P= 0.001; 3.25 [2.67, 3.56] vs. 1.65 [1.18, 1.72] m/s, 281.3 [184.3, 364.7] vs. 65.8 [61.2, 71.9] Pa at peak systole, P= 0.001) and lower minimal WSS and MFRs (0.07 [0.03, 0.13] vs. 0.52 [0.45, 0.67] Pa, 1.5 [1.0, 3.0] vs. 11.0 [8.0, 11.3] g/s at end diastole, P= 0.001; 0.08 [0.03, 0.19] vs. 0.70 [0.60, 0.81] Pa, 2.0 [1.3, 3.3] vs. 16.5 [13.0, 20.3] g/s at peak systole, P= 0.001) as compared to normal arteries. Stent implantation ameliorated all the alterations of the above hemodynamic factors except low WSS. Hemodynamic factors were significantly changed in severe TRAS. Stent implantation can restore or ameliorate deleterious change of hemodynamic factors except low WSS at stent regions.

Hemodynamics in Transplant Renal Artery Stenosis and its Alteration after Stent Implantation Based on a Patient-specific Computational Fluid Dynamics Model

PubMed Central

Wang, Hong-Yang; Liu, Long-Shan; Cao, Hai-Ming; Li, Jun; Deng, Rong-Hai; Fu, Qian; Zhang, Huan-Xi; Fei, Ji-Guang; Wang, Chang-Xi

2017-01-01

Background: Accumulating studies on computational fluid dynamics (CFD) support the involvement of hemodynamic factors in artery stenosis. Based on a patient-specific CFD model, the present study aimed to investigate the hemodynamic characteristics of transplant renal artery stenosis (TRAS) and its alteration after stent treatment. Methods: Computed tomography angiography (CTA) data of kidney transplant recipients in a single transplant center from April 2013 to November 2014 were reviewed. The three-dimensional geometry of transplant renal artery (TRA) was reconstructed from the qualified CTA images and categorized into three groups: the normal, stenotic, and stented groups. Hemodynamic parameters including pressure distribution, velocity, wall shear stress (WSS), and mass flow rate (MFR) were extracted. The data of hemodynamic parameters were expressed as median (interquartile range), and Mann–Whitney U-test was used for analysis. Results: Totally, 6 normal, 12 stenotic, and 6 stented TRAs were included in the analysis. TRAS presented nonuniform pressure distribution, adverse pressure gradient across stenosis throat, flow vortex, and a separation zone at downstream stenosis. Stenotic arteries had higher maximal velocity and maximal WSS (2.94 [2.14, 3.30] vs. 1.06 [0.89, 1.15] m/s, 256.5 [149.8, 349.4] vs. 41.7 [37.8, 45.3] Pa at end diastole, P = 0.001; 3.25 [2.67, 3.56] vs. 1.65 [1.18, 1.72] m/s, 281.3 [184.3, 364.7] vs. 65.8 [61.2, 71.9] Pa at peak systole, P = 0.001) and lower minimal WSS and MFRs (0.07 [0.03, 0.13] vs. 0.52 [0.45, 0.67] Pa, 1.5 [1.0, 3.0] vs. 11.0 [8.0, 11.3] g/s at end diastole, P = 0.001; 0.08 [0.03, 0.19] vs. 0.70 [0.60, 0.81] Pa, 2.0 [1.3, 3.3] vs. 16.5 [13.0, 20.3] g/s at peak systole, P = 0.001) as compared to normal arteries. Stent implantation ameliorated all the alterations of the above hemodynamic factors except low WSS. Conclusions: Hemodynamic factors were significantly changed in severe TRAS. Stent implantation can restore or ameliorate deleterious change of hemodynamic factors except low WSS at stent regions. PMID:28051019

Postrenal acute kidney injury in a patient with unilateral ureteral obstruction caused by urolithiasis: A case report.

PubMed

Kazama, Itsuro; Nakajima, Toshiyuki

2017-10-01

In patients with bilateral ureteral obstruction, the serum creatinine levels are often elevated, sometimes causing postrenal acute kidney injury (AKI). In contrast, those with unilateral ureteral obstruction present normal serum creatinine levels, as long as their contralateral kidneys are preserved intact. However, the unilateral obstruction of the ureter could affect the renal function, as it humorally influences the renal hemodynamics. A 66-year-old man with a past medical history of hypertension and diabetes mellitus came to our outpatient clinic because of right abdominal dullness. Unilateral ureteral obstruction caused by a radio-opaque calculus in the right upper ureter and a secondary renal dysfunction. As oral hydration and the use of calcium antagonists failed to allow the spontaneous stone passage, extracorporeal shock wave lithotripsy (ESWL) was performed. Immediately after the passage of the stone, the number of red blood cells in the urine was dramatically decreased and the serum creatinine level almost returned to the normal range with the significant increase in glomerular filtration rate. Unilateral ureteral obstruction by the calculus, which caused reflex vascular constriction and ureteral spasm in the contralateral kidney, was thought to be responsible for the deteriorating renal function.

ELABELA Improves Cardio-Renal Outcome in Fatal Experimental Septic Shock.

PubMed

Coquerel, David; Chagnon, Frédéric; Sainsily, Xavier; Dumont, Lauralyne; Murza, Alexandre; Côté, Jérôme; Dumaine, Robert; Sarret, Philippe; Marsault, Éric; Salvail, Dany; Auger-Messier, Mannix; Lesur, Olivier

2017-11-01

Apelin-13 was recently proposed as an alternative to the recommended β-adrenergic drugs for supporting endotoxin-induced myocardial dysfunction. Since Apelin-13 signals through its receptor (Apelin peptide jejunum) to exert singular inotropic/vasotropic actions and to optimize body fluid balance, this candidate pathway might benefit septic shock management. Whether the newly discovered ELABELA (ELA), a second endogenous ligand of the Apelin peptide jejunum receptor highly expressed in the kidney, further improves cardio-renal impairment remains unknown. Interventional study in a rat model of septic shock (128 adult males) to assess the effects of ELA and Apelin-13 on vascular and cardio-renal function. Experiments were performed in a tertiary care University-based research institute. Polymicrobial sepsis-induced cardiac dysfunction was produced by cecal ligation puncture to assess hemodynamic efficacy, cardioprotection, and biomechanics under acute or continuous infusions of the apelinergic agonists ELA or Apelin-13 (39 and 15 µg/kg/hr, respectively) versus normal saline. Apelinergic agonists improved 72-hour survival after sepsis induction, with ELA providing the best clinical outcome after 24 hours. Apelinergic agonist infusion counteracted cecal ligation puncture-induced myocardial dysfunction by improving left ventricular pressure-volume relationship. ELA-treated cecal ligation puncture rats were the only group to 1) display a significant improvement in left ventricular filling as shown by increased E-wave velocity and left ventricular end-diastolic volume, 2) exhibit a higher plasma volume, and 3) limit kidney injury and free-water clearance. These beneficial renal effects were superior to Apelin-13, likely because full-length ELA enabled a distinctive regulation of pituitary vasopressin release. Activation of the apelinergic system by exogenous ELA or Apelin-13 infusion improves cardiovascular function and survival after cecal ligation puncture-induced sepsis. However, ELA proved better than Apelin-13 by improving fluid homeostasis, cardiovascular hemodynamics recovery, and limiting kidney dysfunction in a vasopressinergic-dependent manner.

Novel therapy for renal protection.

PubMed

Zarbock, Alexander; Milles, Kindgen

2015-08-01

Acute kidney injury (AKI) is a common and serious complication that significantly increases morbidity, mortality, and cost of care after surgery. In this article, we review recent studies that deal with strategies for renal protection and the prevention of AKI after surgery. A prerequisite for any prophylactic intervention is the identification of patients at risk for AKI or those with acute kidney damage before kidney function deteriorates. In this context, new biomarkers can help to detect cellular injury early. This way, a window for interventions can be opened. Several studies demonstrated the tissue-protective effect of remote ischemic preconditioning in various organs. There is clear evidence that use of balanced crystalloid fluids and the avoidance of hyperchloremic solutions for infusion therapy can reduce the incidence of AKI. Preliminary data show a protective effect if dexmedetomidine is used as a sedative agent following cardiac surgery. The most important intervention with proven efficacy to protect from AKI is aggressive hemodynamic stabilization. Early identification of patients at risk for AKI is crucial to apply any protective intervention. An improved perioperative management is required to prevent AKI. Although pharmacological therapies aiming to protect AKI are under evaluation, hemodynamic optimization and avoidance of nephrotoxic drugs are critical for perioperative patient.

Renal Aging: Causes and Consequences

PubMed Central

Hughes, Jeremy; Ferenbach, David A.

2017-01-01

Individuals age >65 years old are the fastest expanding population demographic throughout the developed world. Consequently, more aged patients than before are receiving diagnoses of impaired renal function and nephrosclerosis—age–associated histologic changes in the kidneys. Recent studies have shown that the aged kidney undergoes a range of structural changes and has altered transcriptomic, hemodynamic, and physiologic behavior at rest and in response to renal insults. These changes impair the ability of the kidney to withstand and recover from injury, contributing to the high susceptibility of the aged population to AKI and their increased propensity to develop subsequent progressive CKD. In this review, we examine these features of the aged kidney and explore the various validated and putative pathways contributing to the changes observed with aging in both experimental animal models and humans. We also discuss the potential for additional study to increase understanding of the aged kidney and lead to novel therapeutic strategies. PMID:28143966

The Renal Renin-Angiotensin System

ERIC Educational Resources Information Center

Harrison-Bernard, Lisa M.

2009-01-01

The renin-angiotensin system (RAS) is a critical regulator of sodium balance, extracellular fluid volume, vascular resistance, and, ultimately, arterial blood pressure. In the kidney, angiotensin II exerts its effects to conserve salt and water through a combination of the hemodynamic control of renal blood flow and glomerular filtration rate and…

Renal responses to central vascular expansion are suppressed at night in conscious primates

NASA Technical Reports Server (NTRS)

Kass, D. A.; Sulzman, F. M.; Fuller, C. A.; Moore-Ede, M. C.

1980-01-01

The renal and hemodynamic responses of squirrel monkeys to central vascular volume expansion induced by lower body positive pressure (LBPP) during the day and night are investigated. Twelve unanesthetized animals trained to sit in a metabolism chair in which they were restrained only at the waist by a partition separating upper and lower body chambers were subjected to 4 h of continuous LBPP during the day and night, and hemodynamic, urinary and drinking data were monitored. LBPP during day and night is found to induce similar increases in central venous pressure, rises in heart rate and elevations in mean arterial blood pressure. However, although daytime LBPP induced a significant increase in urine flow and sodium excretion, a marked nocturnal inhibition of the renal response to LBPP is observed. Analysis of the time course and circadian regulation patterns of the urinary responses suggests that several separate efferent control pathways are involved.

Renal artery embolization in a child with delayed hemodynamic instability from penetrating knife wound.

PubMed

Barras, M; Pearson, E; Cousin, I; Le Rouzic, C; Thepaut, M; Gentric, J-C; Roue, J-M; Yevich, S; de Vries, P

2018-06-14

Penetrating laceration injury in the pediatric population may present as an acute or delayed life-threatening injury. Although emergent intra-arterial embolization is commonly utilized in adults, few cases have been reported for children. Surgical treatment for severe renal laceration injuries may require complete nephrectomy; an unfortunate outcome for a pediatric patient if a renal-preserving alternative is feasible. We present a case of penetrating renal laceration in a 10-year-old boy treated with intra-arterial embolization of the lacerated dominant renal artery and subsequent renal perfusion by an uninjured accessory renal artery allowing for renal preservation. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Persistent oxidative stress following renal ischemia-reperfusion injury increases ANG II hemodynamic and fibrotic activity

PubMed Central

Leonard, Ellen C.; Beal, Alisa G.; Schleuter, Devin; Friedrich, Jessica

2012-01-01

ANG II is a potent renal vasoconstrictor and profibrotic factor and its activity is enhanced by oxidative stress. We sought to determine whether renal oxidative stress was persistent following recovery from acute kidney injury (AKI) induced by ischemia-reperfusion (I/R) injury in rats and whether this resulted in increased ANG II sensitivity. Rats were allowed to recover from bilateral renal I/R injury for 5 wk and renal blood flow responses were measured. Post-AKI rats showed significantly enhanced renal vasoconstrictor responses to ANG II relative to sham-operated controls and treatment of AKI rats with apocynin (15 mM, in the drinking water) normalized these responses. Recovery from AKI for 5 wk resulted in sustained oxidant stress as indicated by increased dihydroethidium incorporation in renal tissue slices and was normalized in apocynin-treated rats. Surprisingly, the renal mRNA expression for common NADPH oxidase subunits was not altered in kidneys following recovery from AKI; however, mRNA screening using PCR arrays suggested that post-AKI rats had decreased renal Gpx3 mRNA and an increased expression other prooxidant genes such as lactoperoxidase, myeloperoxidase, and dual oxidase-1. When rats were infused for 7 days with ANG II (100 ng·kg−1·min−1), renal fibrosis was not apparent in sham-operated control rats, but it was enhanced in post-AKI rats. The profibrotic response was significantly attenuated in rats treated with apocynin. These data suggest that there is sustained renal oxidant stress following recovery from AKI that alters both renal hemodynamic and fibrotic responses to ANG II, and may contribute to the transition to chronic kidney disease following AKI. PMID:22442209

Acute kidney injury after liver, heart, and lung transplants: dialysis modality, predictors of renal function recovery, and impact on survival.

PubMed

Pham, Phuong-Thu T; Slavov, Carmen; Pham, Phuong-Chi T

2009-07-01

Recipients of nonrenal organ transplants including the liver, heart, and lung are at risk for developing acute kidney injury (AKI) and chronic kidney disease (CKD). Underlying hepatic or cardiopulmonary failure, prolonged intraoperative hemodynamic instability, and the use of calcineurin inhibitors and nephrotoxic medications have all been suggested to be contributory. The incidence of perioperative AKI has been reported to occur in 17% to 95% in liver transplant recipients, 5% to 30% in heart transplant recipients, and 5% to 60% in recipients of lung transplants. Among those who develop AKI, renal replacement therapy is required in 5% to 35%, 5% to 15%, and 8% to 10% in liver, heart, and lung transplant recipients, respectively. The current article presents an overview of the literature on the choice of dialysis modality and its associated advantages and disadvantages in the management of AKI after liver, heart, and lung transplants. Predictive factors for renal function recovery and the impact of AKI and CKD on survival will also be discussed.

Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor

PubMed Central

Ojeda, Norma B.; Royals, Thomas P.

2013-01-01

This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg−1·min−1) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls (P < 0.05). Cotreatment with the Rho kinase inhibitor fasudil (33 μg·kg−1·min−1) significantly attenuated these hemodynamic changes (P < 0.05), but it did not abolish the differential increase in blood pressure above baseline, suggesting that the impact of intrauterine growth restriction on blood pressure in intact male growth-restricted rats is independent of Rho kinase. Gonadectomy in conjunction with fasudil returned blood pressure back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced (P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats. PMID:23344570

Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor.

PubMed

Ojeda, Norma B; Royals, Thomas P; Alexander, Barbara T

2013-04-01

This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg(-1)·min(-1)) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls (P < 0.05). Cotreatment with the Rho kinase inhibitor fasudil (33 μg·kg(-1)·min(-1)) significantly attenuated these hemodynamic changes (P < 0.05), but it did not abolish the differential increase in blood pressure above baseline, suggesting that the impact of intrauterine growth restriction on blood pressure in intact male growth-restricted rats is independent of Rho kinase. Gonadectomy in conjunction with fasudil returned blood pressure back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced (P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats.

Rapid improvement of renal function in patients with acute pulmonary embolism indicates favorable short term prognosis.

PubMed

Kostrubiec, Maciej; Łabyk, Andrzej; Pedowska-Włoszek, Justyna; Pacho, Szymon; Dzikowska-Diduch, Olga; Dul, Przemysław; Ciurzyński, Michał; Bienias, Piotr; Pruszczyk, Piotr

2012-09-01

Various clinical and biochemical parameters predict the prognosis of patients with acute pulmonary embolism(APE). Treatment of APE can improve a patient's hemodynamic status, restoring adequate peripheral organ perfusion. Therefore, we hypothesized that improvement of renal function can predict short term prognosis of APE patients. We evaluated 232 consecutive patients (94 men,aged 67 ± 18 years) with APE proven by spiral computer tomography. Blood samples were collected for creatinine assays on admission and 72 hours later, the glomerular filtration rate(eGFR) was estimated using the MDRD formula. During the first 72 hours, 6 subjects died, while during the first 30 days 24(10%) subjects died (APE mortality 8%). On admission eGFR<60 ml/min was present in 113 patients(49%) and after 72 hours in 85 patients(38%). In 26 patients(11%) eGFR on admission was <60 ml/min and renal function did not improve during subsequent 72 hours. In this group the 30-day all-cause and APE-related mortality rates were 27% and 23%, respectively, while serious adverse events occurred in 38% of them. 206 patients with eGFR>60 ml/min showed a more favorable prognosis (8% 30-day all-cause mortality) than subjects with eGFR<60 ml/min and a stable eGFR during the first 72 hours (27% mortality rate, p<0.003). Persistent renal dysfunction predicted all-cause and PE-related 30-day mortality (hazard risk 2.53(CI 95%:0.96-6.68),p=0.06 and 3.04(CI 95%:1.28-7.26),p=0.01, respectively). Approximately 50% of patients with APE have at least a moderately impaired renal function on admission. Renal function improves within 72 hours in patients with a good prognosis, while "persistent" renal dysfunction indicates an increased mortality. Copyright © 2012 Elsevier Ltd. All rights reserved.

[Renal hemodynamic in hydronephrosis concurrent with hepatobiliary system disorders, its dynamics in the course of treatment].

PubMed

Mambetov, Zh S; Salimov, B G

2016-02-01

This article examines measurements of renal vascular ultrasound in 85 patients with hydronephrosis concurrent with disorders of the gallbladder and biliary tract, depending on severity and dynamics during treatment. The estimation of blood flow changes depending on applied renoprotective and hepatoprotective therapy is provided.

Observation of arterial blood pressure of the primate

NASA Technical Reports Server (NTRS)

Meehan, J. P.; Henry, J. P.

1973-01-01

The developments are reported in physiological instrumentation, surgical procedures, measurement and data analysis techniques, and the definition of flight experiments to determine the effects of prolonged weightlessness on the cardiovascular system of subhuman primates. The development of an implantable telemetric data acquisition system is discussed along with cardiovascular research applications in renal hemodynamics. It is concluded that the implant technique permits a valid interpretation, free of emotional response, for the manipulated variable on physiological functions. It also allows a better definition of normal physiological baseline conditions.

Circulatory and Renal Consequences of Pregnancy in Diabetic NOD Mice

PubMed Central

Burke, S.D.; Barrette, V.F.; David, S.; Khankin, E. V.; Adams, M.A.; Croy, B.A.

2011-01-01

Objectives Women with diabetes have elevated gestational risks for severe hemodynamic complications, including preeclampsia in mid- to late pregnancy. This study employed continuous, chronic radiotelemetry to compare the hemodynamic patterns in non-obese diabetic (NOD) mice who were overtly diabetic or normoglycemic throughout gestation. We hypothesized that overtly diabetic, pregnant NOD mice would develop gestational hypertension and provide understanding of mechanisms in progression of this pathology. Study Design Telemeter-implanted, age-matched NOD females with and without diabetes were assessed for six hemodynamic parameters (mean, systolic, diastolic, pulse pressures, heart rate and activity) prior to mating, over pregnancy and over a 72 hr post-partum interval. Urinalysis, serum biochemistry and renal histopathology were also conducted. Results Pregnant, normoglycemic NOD mice had a hemodynamic profile similar to other inbred strains, despite insulitis. This pattern was characterized by an interval of pre-implantation stability, post implantation decline in arterial pressure to mid gestation, and then a rebound to pre-pregnancy baseline during later gestation. Overtly diabetic NOD mice had a blood pressure profile that was normal until mid-gestation then become mildly hypotensive (−7mmHg, P<0.05), severely bradycardic (−80bpm, P<0.01) and showed signs of acute kidney injury. Pups born to diabetic dams were viable but growth restricted, despite their mothers’ failing health, which did not rebound post-partum (−10% pre-pregnancy pressure and HR, P<0.05). Conclusions Pregnancy accelerates circulatory and renal pathologies in overtly diabetic NOD mice and is characterized by depressed arterial pressure from mid-gestation and birth of growth 45 restricted offspring. PMID:22014504

Venovenous Bypass Is Associated With a Lower Incidence of Acute Kidney Injury After Liver Transplantation in Patients With Compromised Pretransplant Renal Function.

PubMed

Sun, Kai; Hong, Fu; Wang, Yun; Agopian, Vatche G; Yan, Min; Busuttil, Ronald W; Steadman, Randolph H; Xia, Victor W

2017-11-01

Although the hemodynamic benefits of venovenous bypass (VVB) during liver transplantation (LT) are well appreciated, the impact of VVB on posttransplant renal function is uncertain. The aim of this study was to determine if VVB was associated with a lower incidence of posttransplant acute kidney injury (AKI). Medical records of adult (≥18 years) patients who underwent primary LT between 2004 and 2014 at a tertiary hospital were reviewed. Patients who required pretransplant renal replacement therapy and intraoperative piggyback technique were excluded. Patients were divided into 2 groups, VVB and non-VVB. AKI, determined by the Acute Kidney Injury Network criteria, was compared between the 2 groups. Propensity match was used to control selection bias that occurred before VVB and multivariable logistic regression was used to control confounding factors during and after VVB. Of 1037 adult patients who met the study inclusion criteria, 247 (23.8%) received VVB. A total of 442 patients (221 patients in each group) were matched. Aftermatch patients were further divided according to a predicted probability AKI model using preoperative creatinine (Cr), VVB, and intraoperative variables into 2 subgroups: normal and compromised pretransplant renal functions. In patients with compromised pretransplant renal function (Cr ≥1.2 mg/dL), the incidence of AKI was significantly lower in the VVB group compared with the non-VVB group (37.2% vs 50.8%; P = .033). VVB was an independent risk factor negatively associated with AKI (odds ratio, 0.1; 95% confidence interval, 0.1-0.4; P = .001). Renal replacement in 30 days and 1-year recipient mortality were not significantly different between the 2 groups. The incidence of posttransplant AKI was not significantly different between the 2 groups in patients with normal pretransplant renal function (Cr <1.2 mg/dL). In this large retrospective study, we demonstrated that utilization of intraoperative VVB was associated with a significantly lower incidence of posttransplant AKI in patients with compromised pretransplant renal function. Further studies to assess the role of intraoperative VVB in posttransplant AKI are warranted.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Zhonghua, E-mail: z.sun@curtin.edu.a; Chaichana, Thanapong

The purpose of the study was to investigate the hemodynamic effect of stent struts (wires) on renal arteries in patients with abdominal aortic aneurysms (AAAs) treated with suprarenal stent-grafts. Two sample patients with AAA undergoing multislice CT angiography pre- and postsuprarenal fixation of stent-grafts were selected for inclusion in the study. Eight juxtarenal models focusing on the renal arteries were generated from the multislice CT datasets. Four types of configurations of stent wires crossing the renal artery ostium were simulated in the segmented aorta models: a single wire crossing centrally, a single wire crossing peripherally, a V-shaped wire crossing centrally,more » and multiple wires crossing peripherally. The blood flow pattern, flow velocity, wall pressure, and wall shear stress at the renal arteries pre- and post-stent-grafting were analyzed and compared using a two-way fluid structure interaction analysis. The stent wire thickness was simulated with a diameter of 0.4, 1.0, and 2.0 mm, and hemodynamic analysis was performed at different cardiac cycles. The interference of stent wires with renal blood flow was mainly determined by the thickness of stent wires and the type of configuration of stent wires crossing the renal ostium. The flow velocity was reduced by 20-30% in most of the situations when the stent wire thickness increased to 1.0 and 2.0 mm. Of the four types of configuration, the single wire crossing centrally resulted in the highest reduction of flow velocity, ranging from 21% to 28.9% among three different wire thicknesses. Wall shear stress was also dependent on the wire thickness, which decreased significantly when the wire thickness reached 1.0 and 2.0 mm. In conclusion, our preliminary study showed that the hemodynamic effect of suprarenal stent wires in patients with AAA treated with suprarenal stent-grafts was determined by the thickness of suprarenal stent wires. Research findings in our study are useful for follow-up of patients treated with suprarenal stent-grafts to ensure long-term safety of the suprarenal fixation.« less

Renal Autoregulation: New Perspectives Regarding the Protective and Regulatory Roles of the Underlying Mechanisms

PubMed Central

Loutzenhiser, Rodger; Griffin, Karen; Williamson, Geoffrey; Bidani, Anil

2006-01-01

When the kidney is subjected to acute increases in blood pressure (BP), renal blood flow (RBF) and glomerular filtration rate (GFR) are observed to remain relatively constant. Two mechanisms, tubuloglomerular feedback (TGF) and the myogenic response, are thought to act in concert to achieve a precise moment-by-moment regulation of GFR and distal salt delivery. The current view is that this mechanism insulates renal excretory function from fluctuations in BP. Indeed, the concept that renal autoregulation is necessary for normal renal function and volume homeostasis has long been a cornerstone of renal physiology. This article presents a very different view, at least in regard to the myogenic component of this response. We suggest that its primary purpose is to protect the kidney against the damaging effects of hypertension. The arguments advanced take into consideration the unique properties of the afferent arteriolar myogenic response that allow it to protect against the oscillating systolic pressure, and the accruing evidence that when this response is impaired the primary consequence is not a disturbed volume homeostasis, but rather an increased susceptibility to hypertensive injury. It is suggested that redundant and compensatory mechanisms are capable of achieving volume regulation despite considerable fluctuations in distal delivery and the assumed moment-by-moment regulation of renal hemodynamics is questioned. Evidence is presented suggesting that additional mechanisms may exist to maintain ambient levels of RBF and GFR within normal range despite chronic alterations in BP and severely impaired acute responses to pressure. Finally the implications of this new perspective on the divergent roles of the renal myogenic response to pressure versus the TGF response to changes in distal delivery are considered and it is proposed that, in addition to TGF-induced vasoconstrictor responses, vasodepressor responses to reduced distal delivery may play a more critical role in modulating afferent arteriolar reactivity, in order to integrate the regulatory and protective functions of the renal microvasculature. PMID:16603656

Elevations in serum creatinine with RAAS blockade: why isn't it a sign of kidney injury?

PubMed

Ryan, Michael J; Tuttle, Katherine R

2008-09-01

The aim of this article is to review the pertinent physiology and pathophysiology of the renin-angiotensin-aldosterone system (RAAS), summarize the proven beneficial cardiovascular and renal effects of RAAS blockade, examine clinical situations in which RAAS blockade may induce reductions in glomerular filtration rate, and explore why increases in serum creatinine in the setting of angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) therapy do not necessarily signify the presence of clinically relevant kidney failure. RAAS inhibition appears to reduce the likelihood of atrial fibrillation. RAAS inhibition leads to improved insulin sensitivity and glycemic control, but does not appear to prevent diabetes. The beneficial effects of ACEi/ARB therapy extend to those with significant renal disease. Combination ACEi/ARB is safe, and reduces proteinuria more than either agent alone in patients with macroalbuminuric nephropathy. Acute deteriorations in renal function that result from RAAS inhibition are usually reversible. RAAS blockade exerts potent hemodynamic, antihypertensive, and antiinflammatory effects, and slows progression of kidney disease beyond that due to lowering of blood pressure. The benefit extends to those with advanced disease. In spite of established benefit, ACEi and ARB therapy remains underutilized, in part due to concerns about acute deteriorations in renal function that result from interruption of the RAAS.

Efficacy of an extravascular lung water-driven negative fluid balance protocol.

PubMed

Díaz-Rubia, L; Ramos-Sáez, S; Vázquez-Guillamet, R; Guerrero-López, F; Pino-Sánchez, F; García-Delgado, M; Gómez-Jiménez, F J; Fernández-Mondéjar, E

2015-01-01

To analyze the efficacy of negative fluid balance in hypoxemic patients with an elevated extravascular lung water index (EVLWI). A retrospective observational study was made. Intensive Care Unit of Virgen de las Nieves Hospital (Spain). Forty-four patients participated in the study. We analyzed our database of hypoxemic patients covering a period of 11 consecutive months. We included all hemodynamically stable and hypoxemic patients with EVLWI>9ml/kg. The protocol dictates a negative fluid balance between 500 and 1500ml/day. We analyzed the impact of this negative fluid balance strategy upon pulmonary, hemodynamic, and renal function. Demographic data, severity scores, clinical, hemodynamic, pulmonary, metabolic and renal function data. Thirty-three patients achieved negative fluid balance (NFB group) and 11 had a positive fluid balance (PFB group). In the former group, PaO2/FiO2 improved from 145 (IQR 106, 200) to 210mmHg (IQR 164, 248) (p<0.001), and EVLWI decreased from 14 (11, 18) to 10ml/kg (8, 14) (p<0.001). In the PFB group, EVLWI also decreased from 11 (10, 14) to 10ml/kg (8, 14) at the end of the protocol (p=0.004). For these patients there were no changes in oxygenation, with a PaO2/FiO2 of 216mmHg (IQR 137, 260) at the beginning versus 205mmHg (IQR 99,257) at the end of the study (p=0.08). Three out of four hypoxic patients with elevated EVLWI tolerated the NFB protocol. In these subjects, the improvement of various analyzed physiological parameters was greater and faster than in those unable to complete the protocol. Patients who did not tolerate the protocol were usually in more severe condition, though a larger sample would be needed to detect specific characteristics of this group. Copyright © 2014 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

Renal hemodynamics and renin-angiotensin system activity in humans with multifocal renal artery fibromuscular dysplasia.

PubMed

van Twist, Daan J L; Houben, Alphons J H M; de Haan, Michiel W; de Leeuw, Peter W; Kroon, Abraham A

2016-06-01

Fibromuscular dysplasia (FMD) is the second most common cause of renovascular hypertension. Nonetheless, knowledge on the renal microvasculature and renin-angiotensin system (RAS) activity in kidneys with FMD is scarce. Given the fairly good results of revascularization, we hypothesized that the renal microvasculature and RAS are relatively spared in kidneys with FMD. In 58 hypertensive patients with multifocal renal artery FMD (off medication) and 116 matched controls with essential hypertension, we measured renal blood flow (Xenon washout method) per kidney and drew blood samples from the aorta and both renal veins to determine renin secretion and glomerular filtration rate per kidney. We found that renal blood flow and glomerular filtration rate in FMD were comparable to those in controls. Although systemic renin levels were somewhat higher in FMD, renal renin secretion was not elevated. Moreover, in patients with unilateral FMD, no differences between the affected and unaffected kidney were observed with regard to renal blood flow, glomerular filtration rate, or renin secretion. In men, renin levels and renin secretion were higher as compared with women. The renal blood flow response to RAS modulation (by intrarenal infusion of angiotensin II, angiotensin-(1-7), an angiotensin II type 1 receptor blocker, or a nitric oxide synthase blocker) was also comparable between FMD and controls. Renal blood flow, glomerular filtration, and the response to vasoactive substances in kidneys with multifocal FMD are comparable to patients with essential hypertension, suggesting that microvascular function is relatively spared. Renin secretion was not increased and the response to RAS modulation was not affected in kidneys with FMD.

Interaction between alpha 2-adrenergic and angiotensin II systems in the control of glomerular hemodynamics as assessed by renal micropuncture in the rat

NASA Technical Reports Server (NTRS)

Thomson, S. C.; Gabbai, F. B.; Tucker, B. J.; Blantz, R. C.

1992-01-01

The hypothesis that renal alpha 2 adrenoceptors influence nephron filtration rate (SNGFR) via interaction with angiotensin II (AII) was tested by renal micropuncture. The physical determinants of SNGFR were assessed in adult male Munich Wistar rats 5-7 d after ipsilateral surgical renal denervation (DNX). DNX was performed to isolate inhibitory central and presynaptic alpha 2 adrenoceptors from end-organ receptors within the kidney. Two experimental protocols were employed: one to test whether prior AII receptor blockade with saralasin would alter the glomerular hemodynamic response to alpha 2 adrenoceptor stimulation with the selective agonist B-HT 933 under euvolemic conditions, and the other to test whether B-HT 933 would alter the response to exogenous AII under conditions of plasma volume expansion. In euvolemic rats, B-HT 933 caused SNGFR to decline as the result of a decrease in glomerular ultrafiltration coefficient (LpA), an effect that was blocked by saralasin. After plasma volume expansion, B-HT 933 showed no primary effect on LpA but heightened the response of arterial blood pressure, glomerular transcapillary pressure gradient, and LpA to AII. The parallel results of these converse experiments suggest a complementary interaction between renal alpha 2-adrenergic and AII systems in the control of LpA.

Endothelin-1 receptor antagonists protect the kidney against the nephrotoxicity induced by cyclosporine-A in normotensive and hypertensive rats

PubMed Central

Caires, A.; Fernandes, G.S.; Leme, A.M.; Castino, B.; Pessoa, E.A.; Fernandes, S.M.; Fonseca, C.D.; Vattimo, M.F.; Schor, N.; Borges, F.T.

2017-01-01

Cyclosporin-A (CsA) is an immunosuppressant associated with acute kidney injury and chronic kidney disease. Nephrotoxicity associated with CsA involves the increase in afferent and efferent arteriole resistance, decreased renal blood flow (RBF) and glomerular filtration. The aim of this study was to evaluate the effect of Endothelin-1 (ET-1) receptor blockade with bosentan (BOS) and macitentan (MAC) antagonists on altered renal function induced by CsA in normotensive and hypertensive animals. Wistar and genetically hypertensive rats (SHR) were separated into control group, CsA group that received intraperitoneal injections of CsA (40 mg/kg) for 15 days, CsA+BOS and CsA+MAC that received CsA and BOS (5 mg/kg) or MAC (25 mg/kg) by gavage for 15 days. Plasma creatinine and urea, mean arterial pressure (MAP), RBF and renal vascular resistance (RVR), and immunohistochemistry for ET-1 in the kidney cortex were measured. CsA decreased renal function, as shown by increased creatinine and urea. There was a decrease in RBF and an increase in MAP and RVR in normotensive and hypertensive animals. These effects were partially reversed by ET-1 antagonists, especially in SHR where increased ET-1 production was observed in the kidney. Most MAC effects were similar to BOS, but BOS seemed to be better at reversing cyclosporine-induced changes in renal function in hypertensive animals. The results of this work suggested the direct participation of ET-1 in renal hemodynamics changes induced by cyclosporin in normotensive and hypertensive rats. The antagonists of ET-1 MAC and BOS reversed part of these effects. PMID:29267497

Endothelin-1 receptor antagonists protect the kidney against the nephrotoxicity induced by cyclosporine-A in normotensive and hypertensive rats.

PubMed

Caires, A; Fernandes, G S; Leme, A M; Castino, B; Pessoa, E A; Fernandes, S M; Fonseca, C D; Vattimo, M F; Schor, N; Borges, F T

2017-12-11

Cyclosporin-A (CsA) is an immunosuppressant associated with acute kidney injury and chronic kidney disease. Nephrotoxicity associated with CsA involves the increase in afferent and efferent arteriole resistance, decreased renal blood flow (RBF) and glomerular filtration. The aim of this study was to evaluate the effect of Endothelin-1 (ET-1) receptor blockade with bosentan (BOS) and macitentan (MAC) antagonists on altered renal function induced by CsA in normotensive and hypertensive animals. Wistar and genetically hypertensive rats (SHR) were separated into control group, CsA group that received intraperitoneal injections of CsA (40 mg/kg) for 15 days, CsA+BOS and CsA+MAC that received CsA and BOS (5 mg/kg) or MAC (25 mg/kg) by gavage for 15 days. Plasma creatinine and urea, mean arterial pressure (MAP), RBF and renal vascular resistance (RVR), and immunohistochemistry for ET-1 in the kidney cortex were measured. CsA decreased renal function, as shown by increased creatinine and urea. There was a decrease in RBF and an increase in MAP and RVR in normotensive and hypertensive animals. These effects were partially reversed by ET-1 antagonists, especially in SHR where increased ET-1 production was observed in the kidney. Most MAC effects were similar to BOS, but BOS seemed to be better at reversing cyclosporine-induced changes in renal function in hypertensive animals. The results of this work suggested the direct participation of ET-1 in renal hemodynamics changes induced by cyclosporin in normotensive and hypertensive rats. The antagonists of ET-1 MAC and BOS reversed part of these effects.

Atorvastatin prevents the downregulation of aquaporin-2 receptor after bilateral ureteral obstruction and protects renal function in a rat model.

PubMed

Danilovic, Alexandre; Lopes, Roberto Iglesias; Sanches, Talita Rojas; Shimizu, Maria Heloísa Massola; Oshiro, Fabíola M; Andrade, Lúcia; Dénes, Francisco Tibor; Seguro, Antonio Carlos

2012-08-01

To assess the effects of atorvastatin (ATORV) on renal function after bilateral ureteral obstruction (BUO), measuring inulin clearance and its effect on renal hemodynamic, filtration, and inflammatory response, as well as the expression of Aquaporin-2 (AQP2) in response to BUO and after the release of BUO. Adult Munich-Wistar male rats were subjected to BUO for 24 hours and monitored during the following 48 hours. Rats were divided into 5 groups: sham operated (n = 6); sham + ATORV (n = 6); BUO (n = 6); BUO + ATORV (10 mg/kg in drinking water started 2 days before BUO [n = 5]; and BUO + ATORV (10 mg/kg in drinking water started on the day of the release of BUO [n = 5]). We measured blood pressure (BP, mm Hg); inulin clearance (glomerular filtration rate [GFR]; mL/min/100 g); and renal blood flow (RBF, mL/min, by transient-time flowmeter). Inflammatory response was evaluated by histologic analysis of the interstitial area. AQP2 expression was evaluated by electrophoresis and immunoblotting. Renal function was preserved by ATORV treatment, even if initiated on the day of obstruction release, as expressed by GFR, measured by inulin clearance. Relative interstitial area was decreased in both BUO + ATORV groups. Urine osmolality was improved in the ATORV-treated groups. AQP2 protein expression decreased in BUO animals and was reverted by ATORV treatment. ATORV administration significantly prevented and restored impairment in GFR and renal vascular resistance. Furthermore, ATORV also improved urinary concentration by reversing the BUO-induced downregulation of AQP2. These findings have significant clinical implication in treating obstructive nephropathy. Copyright © 2012 Elsevier Inc. All rights reserved.

Abnormal Neurocirculatory Control During Exercise in Humans with Chronic Renal Failure

PubMed Central

Park, Jeanie; Middlekauff, Holly R.

2014-01-01

Abnormal neurocirculatory control during exercise is one important mechanism leading to exercise intolerance in patients with both end-stage renal disease (ESRD) and earlier stages of chronic kidney disease (CKD). This review will provide an overview of mechanisms underlying abnormal neurocirculatory and hemodynamic responses to exercise in patients with kidney disease. Recent studies have shown that ESRD and CKD patients have an exaggerated increase in blood pressure (BP) during both isometric and rhythmic exercise. Subsequent studies examining the role of the exercise pressor reflex in the augmented pressor response revealed that muscle sympathetic nerve activity (MSNA) was not augmented during exercise in these patients, and metaboreflex-mediated increases in MSNA were blunted, while mechanoreflex-mediated increases were preserved under basal conditions. However, normalizing the augmented BP response during exercise via infusion of nitroprusside (NTP), and thereby equalizing baroreflex-mediated suppression of MSNA, an important modulator of the final hemodynamic response to exercise, revealed that CKD patients had an exaggerated increase in MSNA during isometric and rhythmic exercise. In addition, mechanoreflex-mediated control was augmented, and metaboreceptor blunting was no longer apparent in CKD patients with baroreflex normalization. Factors leading to mechanoreceptor sensitization, and other mechanisms underlying the exaggerated exercise pressor response, such as impaired functional sympatholysis, should be investigated in future studies. PMID:25458430

Biophysical properties of normal and diseased renal glomeruli.

PubMed

Wyss, Hans M; Henderson, Joel M; Byfield, Fitzroy J; Bruggeman, Leslie A; Ding, Yaxian; Huang, Chunfa; Suh, Jung Hee; Franke, Thomas; Mele, Elisa; Pollak, Martin R; Miner, Jeffrey H; Janmey, Paul A; Weitz, David A; Miller, R Tyler

2011-03-01

The mechanical properties of tissues and cells including renal glomeruli are important determinants of their differentiated state, function, and responses to injury but are not well characterized or understood. Understanding glomerular mechanics is important for understanding renal diseases attributable to abnormal expression or assembly of structural proteins and abnormal hemodynamics. We use atomic force microscopy (AFM) and a new technique, capillary micromechanics, to measure the elastic properties of rat glomeruli. The Young's modulus of glomeruli was 2,500 Pa, and it was reduced to 1,100 Pa by cytochalasin and latunculin, and to 1,400 Pa by blebbistatin. Cytochalasin or latrunculin reduced the F/G actin ratios of glomeruli but did not disrupt their architecture. To assess glomerular biomechanics in disease, we measured the Young's moduli of glomeruli from two mouse models of primary glomerular disease, Col4a3(-/-) mice (Alport model) and Tg26(HIV/nl) mice (HIV-associated nephropathy model), at stages where glomerular injury was minimal by histopathology. Col4a3(-/-) mice express abnormal glomerular basement membrane proteins, and Tg26(HIV/nl) mouse podocytes have multiple abnormalities in morphology, adhesion, and cytoskeletal structure. In both models, the Young's modulus of the glomeruli was reduced by 30%. We find that glomeruli have specific and quantifiable biomechanical properties that are dependent on the state of the actin cytoskeleton and nonmuscle myosins. These properties may be altered early in disease and represent an important early component of disease. This increased deformability of glomeruli could directly contribute to disease by permitting increased distension with hemodynamic force or represent a mechanically inhospitable environment for glomerular cells.

Hemoadsorption in cardiac shock with biventricular failure and giant-cell myocarditis: A case report.

PubMed

Dogan, Günes; Hanke, Jasmin; Puntigam, Jakob; Haverich, Axel; Schmitto, Jan D

2018-05-01

Giant-cell myocarditis represents a rare and often fatal autoimmune disorder. Despite extracorporeal life support being a valid treatment option, alternatives to control the underlying inflammatory response remain sparse. A new hemoadsorption device (CytoSorb) has recently been introduced to treat patients with an excessive inflammatory response. A 57-year-old patient developed fulminant right heart failure, respiratory insufficiency, hemodynamic instability, and oliguric-anuric renal failure. An extracorporeal life support together with an Impella was implanted for circulatory support. Due to non-pulsatility, acontractility of the left ventricle and a heavily reduced right ventricular function, a left ventricular assist device implantation and change from extracorporeal life support to veno-pulmonary arterial extracorporeal membrane oxygenation was performed. Since adequate hemodynamic stabilization could not be achieved and due to increasing inflammatory mediators and bilirubin levels, the decision was made to additionally integrate a CytoSorb hemoadsorber into the system. The combined treatment resulted in a clear and steady improvement in hemodynamics and the inflammatory condition with marked reductions in all measured parameters throughout the treatment period. Metabolic acidosis resolved and liver function improved. Extracorporeal life support therapy represents a bridging approach to heart transplantation or to cardiac recovery and can be complemented by CytoSorb as an independent therapeutic option. The patient described herein with giant-cell myocarditis and fulminant cardiac failure who received substantial extracorporeal support in combination with CytoSorb hemoadsorption therapy benefited in terms of an improvement of organ function and his inflammatory situation.

Hemodynamic Functions of Fenestrated Stent Graft under Resting, Hypertension, and Exercise Conditions

PubMed Central

Kandail, Harkamaljot Singh; Hamady, Mohamad; Xu, Xiao Yun

2016-01-01

The aim of this study was to assess the hemodynamic performance of a patient-specific fenestrated stent graft (FSG) under different physiological conditions, including normal resting, hypertension, and hypertension with moderate lower limb exercise. A patient-specific FSG model was constructed from computed tomography images and was discretized into a fine unstructured mesh comprising tetrahedral and prism elements. Blood flow was simulated using Navier–Stokes equations, and physiologically realistic boundary conditions were utilized to yield clinically relevant results. For a given cycle-averaged inflow of 2.08 L/min at normal resting and hypertension conditions, approximately 25% of flow was channeled into each renal artery. When hypertension was combined with exercise, the cycle-averaged inflow increased to 6.39 L/min but only 6.29% of this was channeled into each renal artery, which led to a 438.46% increase in the iliac flow. For all the simulated scenarios and throughout the cardiac cycle, the instantaneous flow streamlines in the FSG were well organized without any notable flow recirculation. This well-organized flow led to low values of endothelial cell activation potential, which is a hemodynamic metric used to identify regions at risk of thrombosis. The displacement forces acting on the FSG varied with the physiological conditions, and the cycle-averaged displacement force at normal rest, hypertension, and hypertension with exercise was 6.46, 8.77, and 8.99 N, respectively. The numerical results from this study suggest that the analyzed FSG can maintain sufficient blood perfusion to the end organs at all the simulated conditions. Even though the FSG was found to have a low risk of thrombosis at rest and hypertension, this risk can be reduced even further with moderate lower limb exercise. PMID:27379242

The effect of discharge voltage on renal injury and impairment caused by lithotripsy in the pig.

PubMed

Connors, B A; Evan, A P; Willis, L R; Blomgren, P M; Lingeman, J E; Fineberg, N S

2000-02-01

The present study was designed to determine the effects of shock wave voltage (kV) on lesion size and renal function induced by shock wave lithotripsy (SWL) in the 6- to 8-wk-old pig. Each SWL-treated pig received 2000 shock waves at 12, 18, or 24 kV to the lower pole calyx of one kidney. A group of sham SWL pigs served as time controls. Bilateral GFR, renal plasma flow (RPF), and para-aminohippurate (PAH) extraction were measured 1 h before and 1 and 4 h after SWL in all treated and sham animals. The kidneys were removed at the end of each experiment for morphometric analysis. The SWL-induced lesion increased significantly in size as shock wave energy was increased from 12 to 24 kV. PAH extraction, a measure of tubular function, was not significantly affected at 12 kV, was transiently reduced at 18 kV, and was reduced for the duration of the experiment at 24 kV. GFR and RPF, however, were significantly and similarly reduced at the 1 h post-SWL period at all three kilovolt levels. At the 4-h post-SWL period, both GFR and RPF had returned to baseline levels. Lesion size and tubular injury were correlated with changes in kilovoltage, while changes in renal hemodynamics were already maximal at the lowest discharge voltage. These findings suggest that renal microvessels are highly sensitive to shock waves and that frank injury to tubules and vessels may be more closely related to discharge energy than is renal blood flow.

HRV Influence During Renal Transplantation Procedure on Long-Term Mortality.

PubMed

Biernawska, J; Kotfis, K; Kaczmarczyk, M; Błaszczyk, W; Barnik, E; Żukowski, M

2016-06-01

The autonomic nervous system plays an important role in heart function regulation. One of the most acknowledged methods for noninvasive measurement of autonomic system activity is to determine heart rate variability (HRV). Reduced HRV parameters-heart rate rigidity/stiffness-are an independent prognostic factor of sudden cardiac death risk because of arrhythmia. Renal transplantation is an important factor in HRV changes because of hemodynamic and ion disturbances. The main purpose of this study was to determine the influence of HRV disturbances during renal transplantation procedures on long-term mortality in patients with chronic kidney disease. A prospective observation study was performed in the Department of Anesthesiology, Intensive Care, and Acute Poisoning, Pomeranian Medical University, Szczecin, Poland. There were 75 patients (mean age, 47 ± 12 years; 42 men) treated with renal transplantation between 2008 and 2010. Patients were monitored with electrocardiographic tracing with the use of 7 electrodes in position type B. The final stage of analysis was to determine the possible relationship between HRV parameters during the perioperative period and the number of deaths within a 5-year follow-up. HRV parameters during the perioperative period of renal transplantation and the number of deaths within a 5-year follow-up, measured by use of the Holter method, did not differ among patients in the studied population. HRV is a noninvasive and confirmed tool used for the evaluation of autonomic function and mortality risk in patients with end-stage renal disease. HRV parameters recorded in the perioperative period are not optimal stratification tools for estimating the risk of cardiac deaths in patients with end-stage renal disease. Copyright © 2016 Elsevier Inc. All rights reserved.

Renal parameter estimates in unrestrained dogs

NASA Technical Reports Server (NTRS)

Rader, R. D.; Stevens, C. M.

1974-01-01

A mathematical formulation has been developed to describe the hemodynamic parameters of a conceptualized kidney model. The model was developed by considering regional pressure drops and regional storage capacities within the renal vasculature. Estimation of renal artery compliance, pre- and postglomerular resistance, and glomerular filtration pressure is feasible by considering mean levels and time derivatives of abdominal aortic pressure and renal artery flow. Changes in the smooth muscle tone of the renal vessels induced by exogenous angiotensin amide, acetylcholine, and by the anaesthetic agent halothane were estimated by use of the model. By employing totally implanted telemetry, the technique was applied on unrestrained dogs to measure renal resistive and compliant parameters while the dogs were being subjected to obedience training, to avoidance reaction, and to unrestrained caging.

Comparison between the effects of amlodipine and lisinopril on proteinuria in nondiabetic renal failure: a double-blind, randomized prospective study.

PubMed

Janssen, J J; Gans, R O; van der Meulen, J; Pijpers, R; ter Wee, P M

1998-09-01

Double-blind, randomized controlled studies of longer than 1 week in duration comparing the antiproteinuric potential of long-acting dihydropyridine calcium channel blockers with that of angiotensin converting enzyme (ACE) inhibitors are lacking. Therefore, we performed such a study in patients with nondiabetic renal disease and proteinuria. After a 4-week wash-out period in which patients did not use any medication known to affect proteinuria, 21 patients were randomized in a double-blind fashion to receive either the calcium channel blocker amlodipine (Amlo, 5 to 10 mg) or the ACE-inhibitor lisinopril (Lis, 5 to 10 mg). Throughout the 16-week study period, blood pressure, creatinine clearances, and proteinuria were measured every 2 weeks. In addition, device-measured blood pressure and renal hemodynamic studies were performed at the start and end of the study. Systolic blood pressure fell in the Lis group from 163+/-7 (SEM) to 140+/-8 mm Hg (P < .01) and from 157+/-10 to 147+/-6 mm Hg in the Amlo group; diastolic blood pressure fell from 101+/-3 to 86+/-7 mm Hg in the Lis group and from 98+/-3 to 91+/-2 mm Hg in the Amlo group. Renal hemodynamics were not affected by amlodipine treatment, whereas a fall in glomerular filtration rate (GFR) was seen in lisinopril-treated patients (from 55+/-11 to 50+/-10 mL/min; P < .01). Amlodipine did not significantly affect proteinuria. Lisinopril induced a decline in the protein-creatinine ratio with a maximal effect reached after 12 to 16 weeks of therapy (from 0.39+/-0.17 to 0.26 +/-0.11 g/mmol; P < .009). In conclusion, we could not demonstrate an antiproteinuric effect of the long-acting dihydropyridine calcium channel blocker amlodipine, whereas therapy with the ACE-inhibitor lisinopril resulted in a decrease in proteinuria. Amlodipine did not affect renal hemodynamics, whereas lisinopril induced a fall in GFR.

Cockcroft-Gault revisited: New de-liver-ance on recommendations for use in cirrhosis.

PubMed

Scappaticci, Gianni B; Regal, Randolph E

2017-01-28

The Cockcroft-Gault (CG) equation has become perhaps the most popular practical approach for estimating renal function among health care professionals. Despite its widespread use, clinicians often overlook not only the limitations of the original serum creatinine (SCr) based equation, but also may not appreciate the validity of the many variations used to compensate for these limitations. For cirrhotic patients in particular, the underlying pathophysiology of the disease contributes to a falsely low SCr, thereby overestimating renal function with use of the CG equation in this population. We reviewed the original CG trial from 1976 along with data surrounding clinician specific alterations to the CG equation that followed through time. These alterations included different formulas for body weight in obese patients and the "rounding up" approach in patients with low SCr. Additionally, we described the pathophysiology and hemodynamic changes that occur in cirrhosis; and reviewed several studies that attempted to estimate renal function in this population. The evidence we reviewed regarding the most accurate manipulation of the original CG equation to estimate creatinine clearance (CrCl) was inconclusive. Unfortunately, the homogeneity of the patient population in the original CG trial limited its external validity. Elimination of body weight in the CG equation actually produced the estimate closest to the measure CrCl. Furthermore, "rounding up" of SCr values often underestimated CrCl. This approach could lead to suboptimal dosing of drug therapies in patients with low SCr. In cirrhotic patients, utilization of SCr based methods overestimated true renal function by about 50% in the literature we reviewed.

Optical monitoring of kidney oxygenation and hemodynamics using a miniaturized near-infrared sensor

NASA Astrophysics Data System (ADS)

Shadgan, Babak; Macnab, Andrew; Nigro, Mark; Nguan, Christopher

2017-02-01

Background: Following human renal allograft transplant primary graft dysfunction can occur early in the postoperative period as a result of acute tubular necrosis, acute rejection, drug toxicity, and vascular complications. Successful treatment of graft dysfunction requires early detection and accurate diagnosis so that disease-specific medical and/or surgical intervention can be provided promptly. However, current diagnostic methods are not sensitive or specific enough, so that identifying the cause of graft dysfunction is problematic and often delayed. Near-infrared spectroscopy (NIRS) is an established optical method that monitors changes in tissue hemodynamics and oxygenation in real time. We report the feasibility of directly monitoring kidney the kidney in an animal model using NIRS to detect renal ischemia and hypoxia. Methods: In an anesthetized pig, a customized continuous wave spatially resolved (SR) NIRS sensor was fixed directly to the surface of the surgically exposed kidney. Changes in the concentration of oxygenated (O2Hb) deoxygenated (HHb) and total hemoglobin (THb) were monitored before, during and after renal artery clamping and reperfusion, and the resulting fluctuations in chromophore concentration from baseline used to measure variations in renal perfusion and oxygenation. Results: On clamping the renal artery THb and O2Hb concentrations declined progressively while HHb rose. With reperfusion after releasing the artery clamp O2Hb and THb rose while HHb fell with all parameters returning to its baseline. This pattern was similar in all three trials. Conclusion: This pilot study indicates that a miniaturized NIRS sensor applied directly to the surface of a kidney in an animal model can detect the onset of renal ischemia and tissue hypoxia. With modification, our NIRS-based method may contribute to early detection of renal vascular complications and graft dysfunction following renal transplant.

Effects of an anti-G suit on the hemodynamic and renal responses to positive /+Gz/ acceleration

NASA Technical Reports Server (NTRS)

Shubrooks, S. J., Jr.; Epstein, M.; Duncan, D. C.

1974-01-01

The effects of the currently used U.S. Air Force (CSU-12/P) anti-G suit on renal function during positive radial acceleration (+Gz) were assessed in seven normal male subjects in balance on a 200 meq sodium diet. Following suit inflation in the seated position, +2.0 Gz for 30 min resulted in a decrease in the rate of sodium excretion from 125 plus or minus 19 to 60 plus or minus 14 microeq/min, which persisted during a 25-min recovery period. Fractional excretion of sodium also decreased significantly during +Gz. The magnitude of the antinatriuresis was indistinguishable from that observed during +Gz without suit inflation. In contrast to the antinatriuresis observed during centrifugation without suit, however, the antinatriuresis with suit was mediated primarily by an enhanced tubular reabsorption of sodium.

Use of venoarterial extracorporeal membrane oxygenation in fulminant chagasic myocarditis as a bridge to heart transplant

PubMed Central

Durães, André Rodrigues; Figueira, Fernando Augusto Marinho dos Santos; Lafayette, André Rabelo; Martins, Juliana de Castro Solano; Juliano Cavalcante de, Sá

2015-01-01

A 17-year-old Brazilian male presented with progressive dyspnea for 15 days, worsening in the last 24 hours, and was admitted in respiratory failure and cardiogenic shock, with multiple organ dysfunctions. Echocardiography showed a left ventricle ejection fraction of 11%, severe diffuse hypokinesia, and a systolic pulmonary artery pressure of 50mmHg, resulting in the need for hemodynamic support with dobutamine (20mcg/kg/min) and noradrenaline (1.7mcg/kg/min). After 48 hours with no clinical or hemodynamic improvement, an extracorporeal membrane oxygenation was implanted. The patient presented with hemodynamic, systemic perfusion and renal and liver function improvements; however, his cardiac function did not recover after 72 hours, and he was transfer to another hospital. Air transport was conducted from Salvador to Recife in Brazil. A heart transplant was performed with rapid recovery of both liver and kidney functions, as well as good graft function. Histopathology of the explanted heart showed chronic active myocarditis and amastigotes of Trypanosoma cruzi. The estimated global prevalence of T. cruzi infections declined from 18 million in 1991, when the first regional control initiative began, to 5.7 million in 2010. Myocarditis is an inflammatory disease due to infectious or non-infectious conditions. Clinical manifestation is variable, ranging from subclinical presentation to refractory heart failure and cardiogenic shock. Several reports suggest that the use of extracorporeal membrane oxygenation in patients presenting with severe refractory myocarditis is a potential bridging therapy to heart transplant when there is no spontaneous recovery of ventricular function. In a 6-month follow-up outpatient consult, the patient presented well and was asymptomatic. PMID:26761479

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sfakianakis, G.; Kyriakides, G.; Jaffe, D.

Renal scintigraphy has a sensitivity of 85% and it is not entirely specific for RVH. Angiotensino converting enzyme inhibitors (captopril or enalapril) increase the sensitivity and specificity of differential renal vein renin determinations for diagnosing potentially curable RVH, but this is an invasive test. Captopril decreases renal function in RVH through alterations in renal hemodynamics of the affected kidney. The authors studied the yield of one visit captopril renography for the diagnosis of potentially curable renovascular hypertension. Twelve studies in patients with clinical RVH were performed without technical problems as following: After hydration (10ml/kg) the patient was injected iv withmore » 300 ..mu..Ci of I-131-Hippuran and routine imaging in 2 min intervals with computer assisted generation of renograms in 30 sec intervals was performed for at least twenty min. Three hours later the patient received an oral dose of 50mg (weight adjusted for children) of captopril and one hour later the above test was repeated. Four patients showed normal baseline scintigraphy but unilateral decrease in split function and increase in Hippuran transit time (cortical retention at 20 min); two of them, who had angiography and transluminal angioplasty, were cured and repeat studies showed no effect of captopril. Six patients had normal studies (without response to captopril) two with proven lack of RVH (one angiography and one transient post transplantation hypertension); the remaining are followed clinically. The noninvasive approach appears promising for the diagnosis of potentially curable RVH.« less

Effect of a keto acid-amino acid supplement on the metabolism and renal elimination of branched-chain amino acids in patients with chronic renal insufficiency on a low protein diet.

PubMed

Teplan, V; Schück, O; Horácková, M; Skibová, J; Holecek, M

2000-10-27

The aim of our study was to evaluate the effect of a low-protein diet supplemented with keto acids-amino acids on renal function and urinary excretion of branched-chain amino acids (BCAA) in patients with chronic renal insufficiency (CRI). In a prospective investigation 28 patients with CRI (16 male, 12 female, aged 28-66 yrs, CCr 18.6 +/- 10.2 ml/min) on a low-protein diet (0.6 g of protein /kg BW/day and energy intake 140 kJ/kg BW/day) for a period of one month were included. Subsequently, this low protein diet was supplemented with keto acids-amino acids at a dose of 0.1 g/kg BW/day orally for a period of 3 months. Examinations performed at baseline and at the end of the follow-up period revealed significant increase in the serum levels of BCAA leucine (p < 0.02), isoleucine (p < 0.03), and valine (p < 0.02) while their renal fractional excretion declined (p < 0.02, p < 0.01 resp.). Keto acid-amino acid administration had no effect on renal function and on the clearance of inulin, para-aminohippuric acid. Endogenous creatinine and urea clearance remained unaltered. A significant correlation between fractional excretion of sodium and leucine (p < 0.05) and a hyperbolic relationship between inulin clearance and fractional excretion of BCAA (p < 0.01) were seen. Moreover, a significant decrease in proteinuria (p < 0.02), plasma urea concentration and renal urea excretion and a rise in albumin level (p < 0.03) were noted. We conclude that in patients with CRI on a low protein diet the supplementation of keto acids-amino acids does not affect renal hemodynamics, but is associated--despite increases in plasma concentrations--with a reduction of renal amino acid and protein excretion suggesting induction of alterations in the tubular transport mechanisms.

Kidney disease in heart failure: the importance of novel biomarkers for type 1 cardio-renal syndrome detection.

PubMed

Palazzuoli, Alberto; McCullough, Peter A; Ronco, Claudio; Nuti, Ranuccio

2015-08-01

Chronic kidney disease (CKD) in heart failure (HF) has been recognized as an independent risk factor for adverse outcome, although the most important clinical trials tend to exclude patients with moderate and severe renal insufficiency. Despite this common association, the precise pathophysiological connection and liaison between heart and kidney is partially understood. Moreover, is it not enough considering how much cardio-renal syndrome type 1 is attributable to previous CKD, and how much to new-onset acute kidney injury (AKI). Neither development of AKI, its progression and time nor duration is related to an adverse outcome. An AKI definition is not universally recognized, and many confounding terms have been used in literature: "worsening renal function", "renal impairment", "renal dysfunction", etc., are all names that contribute to misunderstanding, and do not facilitate an universal classification. Therefore, AKI development should be the consequence of the basal clinical characteristics of patients, different primitive kidney disease and hemodynamic status. AKI could also be the mirror of several underlying associated diseases poorly controlled. Finally, it is not clear which is the optimal laboratory tool for identifying patients with an increased risk of AKI. In the current report, we review the different kidney diseases' impact in HF, and we analyze the modalities for AKI recognition during HF focusing our attention about some new biomarkers with potential application in the current setting.

[Renal angiomyolipoma rupture as a cause of lumbar pain: report of one case].

PubMed

Cifuentes, Melissa; Calleja, Félix; Hola, José; Daviú, Antonio; Jara, Danilo; Vallejos, Humberto

2008-08-01

Renal angiomyolipoma is a benign tumor formed by smooth muscle, adipose tissue and blood vessels. It is commonly found incidentally and its clinical manifestations are pain and abdominal mass or spontaneous tumor rupture with retroperitoneal bleeding. The clinical presentation of a hemorrhagic shock secondary to a retroperitoneal hematoma is uncommon. We report a 40 year-old male who presented to the emergency room with lumbar pain and deterioration of hemodynamic parameters. The CT scan showed a left renal injury associated to an expansive retroperitoneal process. The abdominal exploration, vascular control of the renal pedicle and nephrectomy allowed a successful outcome.

Differences in GFR and Tissue Oxygenation, and Interactions between Stenotic and Contralateral Kidneys in Unilateral Atherosclerotic Renovascular Disease.

PubMed

Herrmann, Sandra M S; Saad, Ahmed; Eirin, Alfonso; Woollard, John; Tang, Hui; McKusick, Michael A; Misra, Sanjay; Glockner, James F; Lerman, Lilach O; Textor, Stephen C

2016-03-07

Atherosclerotic renal artery stenosis (ARAS) can reduce renal blood flow, tissue oxygenation, and GFR. In this study, we sought to examine associations between renal hemodynamics and tissue oxygenation with single-kidney function, pressor hormones, and inflammatory biomarkers in patients with unilateral ARAS undergoing medical therapy alone or stent revascularization. Nonrandomized inpatient studies were performed in patients with unilateral ARAS (>60% occlusion) before and 3 months after revascularization (n=10) or medical therapy (n=20) or patients with essential hypertension (n=32) under identical conditions. The primary study outcome was change in single-kidney GFR. Individual kidney hemodynamics and volume were measured using multidetector computed tomography. Tissue oxygenation (using R(2)* as a measure of deoxyhemoglobin) was determined by blood oxygen level-dependent magnetic resonance imaging at 3 T. Renal vein neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), and plasma renin activity were measured. Total GFR did not change over 3 months in either group, but the stenotic kidney (STK) GFR rose over time in the stent compared with the medical group (+2.2[-1.8 to 10.5] versus -5.3[-7.3 to -0.3] ml/min; P=0.03). Contralateral kidney (CLK) GFR declined in the stent group (43.6±19.7 to 36.6±19.5 ml/min; P=0.03). Fractional tissue hypoxia fell in the STK (fraction R(2)* >30/s: 22.1%±20% versus 14.9%±18.3%; P<0.01) after stenting. Renal vein biomarkers correlated with the degree of hypoxia in the STK: NGAL(r=0.3; P=0.01) and MCP-1(r=0.3; P=0.02; more so after stenting). Renal vein NGAL was inversely related to renal blood flow in the STK (r=-0.65; P<0.001). Biomarkers were highly correlated between STK and CLK, NGAL (r=0.94; P<0.001), and MCP-1 (r=0.96; P<0.001). These results showed changes over time in single-kidney GFR that were not evident in parameters of total GFR. Furthermore, they delineate the relationship of measurable tissue hypoxia within the STK and markers of inflammation in human ARAS. Renal vein NGAL and MCP-1 indicated persistent interactions between the ischemic kidney and both CLK and systemic levels of inflammatory cytokines. Copyright © 2016 by the American Society of Nephrology.

The renal effects of droxidopa are maintained in propranolol treated cirrhotic rats.

PubMed

Rodríguez, Sarai; Raurell, Imma; Ezkurdia, Nahia; Augustin, Salvador; Esteban, Rafael; Genescà, Joan; Martell, María

2015-02-01

Droxidopa improves hemodynamic and renal alterations of cirrhotic rats without changing portal pressure. We aimed to evaluate the effects of a combined treatment with droxidopa and non-selective beta-blockers or statins in order to decrease portal pressure, while maintaining droxidopa beneficial effects. Acute studies combining droxidopa with carvedilol, propranolol or atorvastatin in four-week bile-duct ligated (BDL) rats and a chronic study combining propranolol and droxidopa for 5 days in CCl4 -cirrhotic rats were performed. Hemodynamic values were registered and biochemical parameters from blood and urine samples analyzed. Bile-duct ligated rats treated with carvedilol + droxidopa showed no changes in mean arterial pressure (MAP) and portal pressure (PP) compared to vehicles. Atorvastatin + droxidopa combination also failed to reduce PP, but maintained the beneficial increase in MAP and superior mesenteric artery resistance (SMAR) and decrease in blood flow (SMABF) caused by droxidopa. In contrast, the acute administration of propranolol + droxidopa significantly reduced PP maintaining a mild increase in MAP and improving, in an additive way, the decrease in SMABF and increase in SMAR caused by droxidopa. This combination also preserved droxidopa diuretic effect. When chronically administered to CCl4 -cirrhotic rats, propranolol + droxidopa caused a decrease in PP, a significant reduction in SMABF and an increase in SMAR. The combination did not alter liver function and droxidopa diuretic and natriuretic effect, and even improved free water clearance. Droxidopa could be effective for the renal alterations of cirrhotic patients on propranolol therapy and the combination of both drugs may balance the adverse effects of each treatment. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Metformin associated lactic acidosis (MALA): clinical profiling and management.

PubMed

Moioli, Alessandra; Maresca, Barbara; Manzione, Andrea; Napoletano, Antonello Maria; Coclite, Daniela; Pirozzi, Nicola; Punzo, Giorgio; Menè, Paolo

2016-12-01

Metformin (MF) accumulation during acute kidney injury is associated with high anion gap lactic acidosis type B (MF-associated lactic acidosis, MALA), a serious medical condition leading to high mortality. Despite dose adjustment for renal failure, diabetic patients with chronic kidney disease (CKD) stage III-IV are at risk for rapid decline in renal function by whatever reason, so that MF toxicity might arise if the drug is not timely withdrawn. Sixteen consecutive patients were admitted to our Hospital's Emergency Department with clinical findings consistent with MALA. Fifteen had prior history of CKD, 60 % of them with GFR between 30 and 60 ml/min. Of these, 5 required mechanical ventilation and cardiovascular support; 3 promptly recovered renal function after rehydration, whereas 10 (62 %) required continuous veno-venous renal replacement treatment. SOFA and SAPS II scores were significantly related to the degree of lactic acidosis. In addition, lactate levels were relevant to therapeutic choices, since they were higher in dialyzed patients than in those on conservative treatment (11.92 mmol/l vs 5.7 mmol/l, p = 0.03). The overall death rate has been 31 %, with poorer prognosis for worse acidemia, as serum pH was significantly lower in non-survivors (pH 6.96 vs 7.16, p > 0.04). Our own data and a review of the literature suggest that aged, hemodynamically frail patients, with several comorbidities and CKD, are at greater risk of MALA, despite MF dosage adjustment. Moreover, renal replacement therapy rather than simple acidosis correction by administration of alkali seems the treatment of choice, based on eventual renal recovery and overall outcome.

Personalized design and virtual evaluation of physician-modified stent grafts for juxta-renal abdominal aortic aneurysms

NASA Astrophysics Data System (ADS)

Sanathkhani, Soroosh; Shroff, Sanjeev G.; Menon, Prahlad G.

2017-02-01

Endovascular aneurysm repair (EVAR) of juxtarenal aortic aneurysms (JAA) is particularly challenging owing to the requirement of suprarenal EVAR graft fixation, which has been associated with significant declines in long term renal function. Therefore, the ability to design fenestrated EVAR grafts on a personalized basis in order to ensure visceral and renal perfusion, is highly desirable. The objectives of this study are: a) To demonstrate novel 3D geometric methods to virtually design and deploy EVAR grafts into a virtually designed JAA, by applying a custom surface mesh deformation tool to a patient-specific descending aortic model reconstructed from computed tomographic (CT) images; and b) To virtually evaluate patient-specific renal flow and wall stresses in these patient-specific virtually EVAR geometries, using computational fluid dynamics (CFD). The presented framework may provide the modern cardiovascular surgeon the ability to leverage non-invasive, pre-operative imaging equipment to personalize and guide EVAR therapeutic strategy. Our CFD studies revealed that virtual EVAR grafting of a patient-specific JAA, with optimal fenestration sites and renal stenting, led to a 179.67±15.95% and 1051.43±18.34% improvement in right and left renal flow rates, respectively, when compared with the baseline patient-specific aortic geometry with renal stenoses, whereas a right and left renal flow improved by 36.44±2.24% and 885.93±12.41%, respectively, relative to the equivalently modeled JAA with renal stenoses, considering averages across the three simulated inflow rate cases. The proposed framework have utility to iteratively optimize suprarenal EVAR fixation length and achieve normal renal wall shear stresses and streamlined juxtarenal hemodynamics.

Renal Hemodynamic and Morphological Changes after 7 and 28 Days of Leptin Treatment: The Participation of Angiotensin II via the AT1 Receptor

PubMed Central

Thieme, Karina; Oliveira-Souza, Maria

2015-01-01

The role of hyperleptinemia in cardiovascular diseases is well known; however, in the renal tissue, the exact site of leptin’s action has not been established. This study was conducted to assess the effect of leptin treatment for 7 and 28 days on renal function and morphology and the participation of angiotensin II (Ang II), through its AT1 receptor. Rats were divided into four groups: sham, losartan (10 mg/kg/day, s.c.), leptin (0.5 mg/kg/day for the 7 days group and 0.25 mg/kg/day for the 28 days group) and leptin plus losartan. Plasma leptin, Ang II and endothelin 1 (ET-1) levels were measured using an enzymatic immuno assay. The systolic blood pressure (SBP) was evaluated using the tail-cuff method. The renal plasma flow (RPF) and the glomerular filtration rate (GFR) were determined by p-aminohippuric acid and inulin clearance, respectively. Urinary Na+ and K+ levels were also analyzed. Renal morphological analyses, desmin and ED-1 immunostaining were performed. Proteinuria was analyzed by silver staining. mRNA expression of renin-angiotensin system (RAS) components, TNF-α and collagen type III was analyzed by quantitative PCR. Our results showed that leptin treatment increased Ang II plasma levels and progressively increased the SBP, achieving a pre-hypertension state. Rats treated with leptin 7 days showed a normal RPF and GFR, but increased filtration fraction (FF) and natriuresis. However, rats treated with leptin for 28 showed a decrease in the RPF, an increase in the FF and no changes in the GFR or tubular function. Leptin treatment-induced renal injury was demonstrated by: glomerular hypertrophy, increased desmin staining, macrophage infiltration in the renal tissue, TNF-α and collagen type III mRNA expression and proteinuria. In conclusion, our study demonstrated the progressive renal morphological changes in experimental hyperleptinemia and the interaction between leptin and the RAS on these effects. PMID:25793389

Tumor necrosis factor-α: regulation of renal function and blood pressure

PubMed Central

Garvin, Jeffrey L.

2013-01-01

Tumor necrosis factor-α (TNF-α) is a pleiotropic cytokine that becomes elevated in chronic inflammatory states such as hypertension and diabetes and has been found to mediate both increases and decreases in blood pressure. High levels of TNF-α decrease blood pressure, whereas moderate increases in TNF-α have been associated with increased NaCl retention and hypertension. The explanation for these disparate effects is not clear but could simply be due to different concentrations of TNF-α within the kidney, the physiological status of the subject, or the type of stimulus initiating the inflammatory response. TNF-α alters renal hemodynamics and nephron transport, affecting both activity and expression of transporters. It also mediates organ damage by stimulating immune cell infiltration and cell death. Here we will summarize the available findings and attempt to provide plausible explanations for such discrepancies. PMID:23515717

Complications of cirrhosis. A 50 years flashback.

PubMed

Møller, Søren; Bendtsen, Flemming

2015-06-01

In patients with cirrhosis and portal hypertension, it is largely the frequency and severity of complications relating to the diseased liver, degree of portal hypertension and hemodynamic derangement that determine the prognosis. It can be considered as a multiple organ failure that apart from the liver involves the heart, lungs, kidneys, the immune systems and other organ systems. Progressive fibrosis of the liver and subsequent metabolic impairment leads to a systemic and splanchnic arteriolar vasodilatation. With the progression of the disease development of portal hypertension leads to formation of esophageal varices and ascites. The circulation becomes hyperdynamic with cardiac, pulmonary as well as renal consequences for dysfunction and reduced survival. Infections and a changed cardiac function known as cirrhotic cardiomyopathy may be involved in further aggravation of other complications such as renal failure precipitating the hepatorenal syndrome. Patients with end-stage liver disease and related complications as for example the hepatopulmonary syndrome can only radically be treated by liver transplantation.

Effect of Shock Wave Lithotripsy on Renal Hemodynamics

NASA Astrophysics Data System (ADS)

Handa, Rajash K.; Willis, Lynn R.; Evan, Andrew P.; Connors, Bret A.

2008-09-01

Extracorporeal shock wave lithotripsy (SWL) can injure tissue and decrease blood flow in the SWL-treated kidney, both tissue and functional effects being largely localized to the region targeted with shock waves (SWs). A novel method of limiting SWL-induced tissue injury is to employ the "protection" protocol, where the kidney is pretreated with low-energy SWs prior to the application of a standard clinical dose of high-energy SWs. Resistive index measurements of renal vascular resistance/impedance to blood flow during SWL treatment protocols revealed that a standard clinical dose of high-energy SWs did not alter RI during SW application. However, there was an interaction between low- and high-energy SWL treatment phases of the "protection" protocol such that an increase in RI (vasoconstriction) was observed during the later half of SW application, a time when tissue damage is occurring during the standard high-energy SWL protocol. We suggest that renal vasoconstriction may be responsible for reducing the degree of tissue damage that normally results from a standard clinical dose of high-energy SWs.

Chronic Inhibition of Renal Outer Medullary Potassium Channel Not Only Prevented but Also Reversed Development of Hypertension and End-Organ Damage in Dahl Salt-Sensitive Rats.

PubMed

Zhou, Xiaoyan; Forrest, Michael J; Sharif-Rodriguez, Wanda; Forrest, Gail; Szeto, Daphne; Urosevic-Price, Olga; Zhu, Yonghua; Stevenson, Andra S; Zhou, Yuchen; Stribling, Sloan; Dajee, Maya; Walsh, Shawn P; Pasternak, Alexander; Sullivan, Kathleen A

2017-02-01

The renal outer medullary potassium (ROMK) channel mediates potassium recycling and facilitates sodium reabsorption through the Na + /K + /2Cl - cotransporter in the loop of Henle and potassium secretion at the cortical collecting duct. Evidence from the phenotype of humans and rodents with functional ROMK deficiency supports the contention that selective ROMK inhibitors (ROMKi) will represent a novel diuretic with potential of therapeutic benefit for hypertension. ROMKi have recently been synthesized by Merck & Co, Inc. The present studies were designed to examine the effects of ROMKi B on systemic hemodynamics, renal function and structure, and vascular function in Dahl salt-sensitive rats. Four experimental groups-control, high-salt diet alone; ROMKi B 3 mg·kg - 1 ·d - 1 ; ROMKi B 10 mg·kg - 1 ·d - 1 ; and hydrochlorothiazide 25 mg·kg - 1 ·d - 1 -were included in prophylactic (from week 1 to week 9 on high-salt diet) and therapeutic studies (from week 5 to week 9 on high-salt diet), respectively. ROMKi B produced sustained blood pressure reduction and improved renal and vascular function and histological alterations induced by a high-salt diet. ROMKi B was superior to hydrochlorothiazide at reducing blood pressure. Furthermore, ROMKi B provided beneficial effects on both the plasma lipid profile and bone mineral density. Chronic ROMK inhibition not only prevented but also reversed the development of hypertension and end-organ damage in Dahl salt-sensitive rats. Our findings suggest a potential utility of ROMKi B as a novel antihypertensive agent, particularly for the treatment of the salt-sensitive hypertension patient population. © 2016 American Heart Association, Inc.

Effects of endothelin receptor antagonists on renal hemodynamics in angiotensin II-infused rats on high NaCl intake.

PubMed

Saeed, Aso; Dibona, Gerald F; Guron, Gregor

2012-01-01

The aim was to investigate effects of selective endothelin (ET) receptor antagonists on renal hemodynamics and dynamic renal blood flow autoregulation (RBFA) in angiotensin II (Ang II)-infused rats on a high NaCl intake. Sprague-Dawley rats received Ang II (250 ng/kg/min, s.c.) and an 8% NaCl diet for 14 days after which renal clearance experiments were performed. After baseline measurements animals were administered either: (a) saline vehicle; (b) ETA receptor antagonist BQ-123 (30 nmol/kg/min); (c) ETB receptor antagonist BQ-788 (30 nmol/kg/min); or (d) BQ-123 + BQ-788, for six consecutive 20-minute clearance periods. BQ-123 reduced arterial pressure (AP) and selectively increased outer medullary perfusion versus vehicle (p<0.05). These effects were attenuated or abolished by combined BQ-123 and BQ-788. BQ-788 reduced renal blood flow and increased renovascular resistance (p<0.05). Ang II-infused rats on high NaCl intake showed abnormalities in dynamic RBFA characterized by an impaired myogenic response that were not significantly affected by ET receptor antagonists. In hypertensive Ang II-infused rats on a high-NaCl intake selective ETA antagonism with BQ-123 reduced AP and specifically increased OM perfusion and these effects were dependent on intact ETB receptor stimulation. Furthermore, ET receptor antagonists did not attenuate abnormalities in dynamic RBFA. Copyright © 2012 S. Karger AG, Basel.

Hemodynamic responses to acute and gradual renal artery stenosis in pigs.

PubMed

Rognant, Nicolas; Rouvière, Olivier; Janier, Marc; Lê, Quoc Hung; Barthez, Paul; Laville, Maurice; Juillard, Laurent

2010-11-01

Reduction of renal blood flow (RBF) due to a renal artery stenosis (RAS) can lead to renal ischemia and atrophy. However in pigs, there are no data describing the relationship between the degree of RAS, the reduction of RBF, and the increase of systemic plasma renin activity (PRA). Therefore, we conducted a study in order to measure the effect of acute and gradual RAS on RBF, mean arterial pressure (MAP), and systemic PRA in pigs. RAS was induced experimentally in six pigs using an occluder placed around the renal artery downstream of an ultrasound flow probe. The vascular occluder was inflated gradually to reduce RBF. At each inflation step, percentage of RAS was measured by digital subtraction angiography (DSA) with simultaneous measurements of RBF, MAP, and PRA. Data were normalized to baseline values obtained before RAS induction. Piecewise regression analysis was performed between percentage of RAS and relative RBF, MAP, and PRA, respectively. In all pigs, the relationship between the degree of RAS and RBF was similar. RBF decreased over a threshold of 42% of RAS, with a rapid drop in RBF when RAS reached 70%. PRA increased dramatically over a threshold of 58% of RAS (+1,300% before occlusion). MAP increased slightly (+15% before occlusion) without identifiable threshold. This study emphasizes that the relation between the degree of RAS and RBF and systemic PRA is not linear and that a high degree of RAS must be reached before the occurrence of significant hemodynamic and humoral effects.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nally, J.V.; Clarke, H.S.; Grecos, G.P.

To assess the effect of CAP on individual kidney function in ..mu..RAS, the authors compared computer assisted 90 second and 15 minute /sup 99m/Tc-DTPA renal flow studies vs /sup 131/I-Hippuran renography with and without CAP. In Group 1 (n=10), angiograms, split function C/sub PAH/, DTPA and Hippuran studies were performed in dogs pre and post ..mu..RAS. Group II animals (n=8) with milder stenosis underwent the same protocol, plus DTPA and Hippuran studies, C/sub PAH/, and C/sub IN/ were performed during CAP (Captopril 1.5 mg/kg bolus and 1.5 mg/min x 60 min.) Recovery DTPA and Hippuran studies (Rec) were performed andmore » were also obtained using nitroprusside (NP) to lower MP to a similar degree as CAP. The authors conclude /sup 99m/Tc-DTPA studies proved superior to Hipurran renography in both Groups I and II. With mild ..mu..RAS, CAP induced a decrease in ipsilateral GFR resulting in striking changes in the /sup 99m/Tc-DTPA curves such that all were now diagnostic of uRAS. These changes appeared specific for CAP and independent of MAP reduction with NP, and /sup 99m/Tc-DTPA renal flow studies with CAP unmask unilateral angiotension II dependent renal hemodynamic changes.« less

Continuous renal replacement therapies: a brief primer for the neurointensivist.

PubMed

Patel, Pritesh; Nandwani, Veena; McCarthy, Paul J; Conrad, Steven A; Keith Scott, L

2010-10-01

Continuous renal replacement therapy (CRRT) is a renal replacement modality that is often used in the ICU setting, including the neuro-ICU. This form of renal replacement therapy has been used classically for acute renal failure in patients with hemodynamic compromise, but is gaining acceptance as a method to control vascular and extra-vascular volume and mediate cytokines in non-renal diseases. Although these uses are briefly discussed, this review concentrates on the different forms of continuous renal replacement, mainly focusing on the technology of convective versus diffusive modalities and briefly on filter technology. There is also discussion on the various anticoagulation regimes used in CRRT including data on performing CRRT without anticoagulation. This review is not meant to be a discussion on the pros and cons of CRRT versus intermittent dialysis, but rather a primer on the technology of CRRT and how this therapy may affect general care of the ICU patient.

STUDIES OF THE RENAL CONCENTRATING MECHANISM IN HUMANS. I. THE EFFECT OF HYPERTHYROIDISM,

DTIC Science & Technology

Summary: (1) The maximum urinary osmolality after dehydration and exogenous vasopressin was significantly decreased during thyrotoxicosis in... thyrotoxicosis , TcH2O during a moderate mannitol diuresis was unchanged in most patients. The data suggest that the decreased Umax and normal TcH2O...in thyrotoxic individuals is probably caused by an increase in medullary blood flow with a decrease in medullary osmolality. (2) Renal hemodynamics

Incidence and management of penetrating renal trauma in patients with multiorgan injury: extended experience at an inner city trauma center.

PubMed

Kansas, Bryan T; Eddy, Michael J; Mydlo, Jack H; Uzzo, Robert G

2004-10-01

Patients with penetrating trauma often have multiorgan involvement that may complicate the management of any single organ system. Here we review the incidence of associated injuries in patients with penetrating renal trauma and our extended experience treating these patients at a busy inner city trauma center. All trauma cases presenting to Temple University Trauma Center during a 6-year period were identified through our institutional databases and were reviewed (5,276). Penetrating trauma represented 41% of all cases (2,163). Of these we identified 123 patients with penetrating renal trauma (5.7%). A total of 93 cases were available for review. Multiorgan injury was staged in the operating room if patients were hemodynamically unstable or radiographically if they were stable. Renal injuries were staged by high dose, single shot excretory urogram in patients taken immediately to surgery or by computerized tomography if stable. Renal injuries were classified using the American Association for Surgery of Trauma (AAST) grading system. AAST classifications were subcategorized for purposes of streamlining. Grade 1 and 2 injuries were grouped as low grade, grades 3 and 4 nonvascular injuries were grouped as intermediate grade, and AAST grade 4 vascular and grade 5 injuries were grouped as high grade. Demographic, clinical and intraoperative variables, as well as number and severity of associated injuries, were then assessed to determine the relationship with various renal surgical outcomes including the requirement of surgical intervention, type of surgical intervention, need for nephrectomy and associated adverse outcomes. The median age of injured patients was 28 years (range 14 to 80). The majority of victims were male (93%). The mechanism of injury was predominantly gunshot wound (GSW, 86%) while 14% were due to stab wounds. Renal injuries were low grade (19%), intermediate grade (44%) and high grade (37%). Nearly all patients with penetrating renal injury had associated multiorgan injury (94.6%). Associated injuries for penetrating renal trauma on the right side predominately involved the liver, small bowel and vertebra while injury to the left kidney was most often associated with trauma to the stomach, colon and spleen. Patients suffered extensive renal injury as evidenced by the high rate of intraoperative urinomas (30.1%) and hematomas (97.5%) identified. In the absence of an expanding hematoma and/or hemodynamic instability, associated injuries by themselves did not increase the risk of nephrectomy. Despite multiorgan penetrating injury 54% of kidneys were salvageable. Isolated penetrating trauma to the kidney is rare. The majority of patients with penetrating renal trauma have associated adjacent organ injuries that may complicate treatment. In the absence of an expanding hematoma with hemodynamic instability, associated multiorgan injuries did not increase the risk of nephrectomy. With appropriate radiographic and/or surgical staging, it is possible to repair and salvage many of these kidneys despite extensive associated intraabdominal trauma.

Correlation of 24-Hour Blood Pressure and Heart Rate Variability to Renal Function Parameters in Hypertensive Patients. The Effect of Smoking.

PubMed

Liakos, Charalampos I; Karpanou, Eva A; Markou, Maria I; Grassos, Charalampos A; Vyssoulis, Gregory P

2015-12-01

Intrarenal hemodynamics depend on blood pressure (BP), heart rate (HR), and smoking. Although BP levels have been associated with kidney function, the effect of HR levels, BP, and HR variability on renal function are less well clarified. This cross-sectional study sought to determine the association of 24-hour BP and HR variability with kidney function in hypertensive patients, stratified by smoking. The study comprised 9600 nondiabetic, never-treated hypertensive individuals without evident renal impairment examined from 1985 to 2014 (aged 53.3±13.4 years, 55.3% males). The 24-hour systolic BP (SBP) and HR variability were estimated via their coefficient of variation (CV =standard deviation×100/mean value) derived from ambulatory recording. The CV SBP-to-CV HR ratio (CV R) was used as a marker of the interplay between 24-hour SBP and HR variability. Renal function was estimated via 24-hour urine creatinine clearance (CrCl), estimated glomerular filtration rate (eGFR), albumin-to-creatinine ratio (ACR), and 24-hour urine α1 -microglobulin. After adjustment for age, sex, and smoking, CV SBP was found to be weakly correlated to eGFR (r=-0.017, P=.1) and somewhat more strongly to CrCl, ACR, and α1 -microglobulin (r=-0.032, 0.072, and 0.065; P=.002, <.001 and <.001, respectively). CV HR was much better related to renal function, with stronger adjusted correlations to CrCl, eGFR, ACR, and α1 -microglobulin (r=0.185, 0.134, -0.306, -0.247; all P<.001, respectively). CV R also showed equally good adjusted correlations (r=-0.175, -0.125, 0.336, 0.262; all P<.001, respectively). Most adjusted correlations for CV HR and CV R were even better in smokers (r=0.213, 0.158, -0.332, -0.272 and -0.183, -0.118, 0.351, 0.275, respectively; all P<.001). CV HR and CV R emerge as better related to kidney function than CV SBP, especially in smokers. The correlation of CV HR and CV SBP to renal function is inverse to each other. ACR and α1 -microglobulin are better related to variability indices than CrCl and eGFR. However, causal relations cannot be proved. © 2015 Wiley Periodicals, Inc.

Subcapsular renal hematoma after ureterorenoscopy: An unknown complication of a known procedure

PubMed Central

Bansal, Ujjwal; Sawant, Ajit; Dhabalia, Jayesh

2010-01-01

Renal subcapsular hematoma is not an uncommon complication after extracorporeal short wave lithotripsy, trauma, renal angiographic procedures and spontaneously in patients of malignancy and in patients on anticoagulation. We present a patient who developed renal subcapsular hematoma after ureterorenoscopy, which has not been mentioned in literature ever. Clinical spectrum varies from spontaneous resolution through acute renal failure to Page kidney. Page kidney is the external compression of a kidney usually caused by a subcapsular hematoma associated with high blood pressure and occasional renal failure. It is named after Dr. Irvin Page who first demonstrated in 1939 that wrapping cellophane tightly around animal kidneys could cause hypertension. Various management options are mentioned in literature and depend upon the severity of hematoma. Percutaneous drainage is a successful option for the management of subcapsular hematoma in hemodynamic stable patients. PMID:20981200

Micro- and Macrocirculatory Changes During Sepsis and Septic Shock in a Rat Model.

PubMed

Hua, Tianfeng; Wu, Xiaobo; Wang, Wei; Li, Hao; Bradley, Jennifer; Peberdy, Mary A; Ornato, Joseph P; Tang, Wanchun

2018-05-01

Microcirculation is the motor of sepsis. In the present study, we investigated whether microcirculatory alterations occur before changes of systemic hemodynamics in a rat model of cecum ligation and puncture (CLP)-induced sepsis. We further investigated renal microcirculatory changes during sepsis and compared those with buccal microcirculation. Twelve male Sprague-Dawley rats were randomized into a sham control group (n = 6) and a CLP group (n = 6). Perfused microvessel density (PVD) and microvascular flow index (MFI) were evaluated using sidestream dark field (SDF) video microscopy at baseline-60, 120, 180, 240, 300, and 360 min following CLP. A semiquantitative score was calculated for vessels of less than 20 μm, primarily representing the capillaries. Hemodynamic measurements such as cardiac output (CO), aortic pressure (AP), heart rate (HR), end-tidal CO2 (ETCO2), blood pH, and lactate were measured simultaneously. The serum cytokine interleukin 6 (IL-6) was measured at baseline-120, 240, and 360 min. In the CLP group, buccal PVD and MFI were reduced at 180 min (P < 0.05 vs. baseline); renal PVD and MFI were reduced at 180 min (P < 0.05 vs. baseline), but MAP and CO did not change until 300 min after CLP. In the rat model of peritonitis-induced sepsis, microcirculatory alterations of both peripheral mucosa and kidney occurred earlier than global hemodynamics. Monitoring the microcirculation may provide a means of early detection of circulatory failure during sepsis. The changes of renal microcirculation correlate with that of buccal during sepsis and septic shock.

Regulation of oxygen utilization by angiotensin II in chronic kidney disease

PubMed Central

Deng, Aihua; Tang, Tong; Singh, Prabhleen; Wang, Chen; Satriano, Joe; Thomson, Scott C; Blantz, Roland C

2010-01-01

Angiotensin II (ANG II) blockade delays progression of chronic kidney disease (CKD) by modifying intrarenal hemodynamics, but the effect on metabolic adaptations has not been examined. Using renal ablation/infarction (A/I) model of CKD in rats at one week, the effects of ANG II blockade by captopril (CAP) and losartan (LOS) on renal O2 consumption (QO2), renal nitric oxide (NO) activity and nitric oxide synthase (NOS) protein expression was examined. A/I kidneys exhibited proteinuria, reduced GFR, renal blood flow (RBF) and NOS-1 protein expression, while QO2 factored by sodium reabsorption (QO2/TNa) was markedly increased. CAP + LOS treatment increased GFR, RBF, and TNa, while QO2 remained unchanged, thus normalizing QO2/TNa. NOS-1 expression was normalized with CAP + LOS, as was proteinuria. Triple antihypertensive therapy administered to control for the blood pressure reduction, and lysine administration to increase GFR and RBF, did not normalize QO2/TNa, suggesting a specific effect of ANG II in elevating QO2/TNa. NOS blockade, to test functional NO activity on QO2 and QO2/TNa, increased QO2 in shams, but not in untreated A/I. The increase in QO2 was restored in CAP + LOS treated A/I. CAP + LOS treatment normalized the increased QO2/TNa and functional NO activity in A/I independent of the blood pressure and GFR effects, providing evidence for an additional mechanism underlying the benefits of ANG II inhibition therapy. PMID:18818681

The emerging role of the endocannabinoid system in the pathogenesis and treatment of kidney diseases.

PubMed

Tam, Joseph

2016-05-01

Endocannabinoids (eCBs) are endogenous lipid ligands that bind to cannabinoid receptors that also mediate the effects of marijuana. The eCB system is comprised of eCBs, anandamide, and 2-arachidonoyl glycerol, their cannabinoid-1 and cannabinoid-2 receptors (CB1 and CB2, respectively), and the enzymes involved in their biosynthesis and degradation. It is present in both the central nervous system and peripheral organs including the kidney. The current review focuses on the role of the eCB system in normal kidney function and various diseases, such as diabetes and obesity, that directly contributes to the development of renal pathologies. Normally, activation of the CB1 receptor regulates renal vascular hemodynamics and stimulates the transport of ions and proteins in different nephron compartments. In various mouse and rat models of obesity and type 1 and 2 diabetes mellitus, eCBs generated in various renal cells activate CB1 receptors and contribute to the development of oxidative stress, inflammation, and renal fibrosis. These effects can be chronically ameliorated by CB1 receptor blockers. In contrast, activation of the renal CB2 receptors reduces the deleterious effects of these chronic diseases. Because the therapeutic potential of globally acting CB1 receptor antagonists in these conditions is limited due to their neuropsychiatric adverse effects, the recent development of peripherally restricted CB1 receptor antagonists may represent a novel pharmacological approach in treating renal diseases.

Extracorporeal shock wave lithotripsy (ESWL) of a renal calculus in a liver transplant recipient: report of a severe complication--a case report.

PubMed

Friedersdorff, F; Buckendahl, J; Fuller, T F; Cash, H

2010-11-01

Extracorporeal shock wave lithotripsy (ESWL) has evolved as a standard treatment modality for calculi of the upper urinary tract. Noninvasive ESWL shows rare life-threatening complications. Herein we have reported the case of a liver transplant recipient who developed severe renal hemorrhage after ESWL of a renal calculus. Transfusion of erythrocytes and platelets led to anaphylactic shock with acute renal failure requiring intensive care. The patient fully recovered shortly thereafter and was discharged home with a residual left kidney stone measuring 8 mm. A 55-year-old man with a single left kidney underwent ESWL due to symptomatic left nephrolithiasis. He had undergone successful liver transplantation 11 years earlier. At the time of ESWL his liver functions were normal and his serum creatinine level was 1.3 mg/dL. Two weeks before the treatment a double pigtail ureteral stent was inserted because of a symptomatic left hydronephrosis. Several hours after ESWL treatment the patient complained of left-sided flank pain. An ultrasound revealed a large subcapsular hematoma of the left kidney, which was confirmed using abdominal computed tomography (CT). With the patient being hemodynamically stable, we opted for conservative management. Despite postinterventional complications, the patient made a fast recovery. ESWL is a noninvasive, safe, and efficient method to treat renal calculi. Patients who are at risk for hemorrhage should undergo close postinterventional monitoring, including red blood cell count and renal ultrasound. Copyright © 2010 Elsevier Inc. All rights reserved.

Elevation of plasma milrinone concentrations in stage D heart failure associated with renal dysfunction.

PubMed

Cox, Zachary L; Calcutt, Marion W; Morrison, Thomas B; Akers, Wendell S; Davis, Mary Beth; Lenihan, Daniel J

2013-09-01

To determine steady state milrinone concentrations in patients with stage D heart failure (HF) with and without renal dysfunction We retrospectively identified patients with stage D HF at a single medical center on continuous milrinonein fusion at the time of plasma collection for entry into a research registry database. Milrinone was prescribed and titrated to improve hemodynamic and clinical status by a cardiologist. Plasma samples were obtained at steady state milrinone concentrations. Patients were stratified by creatinine clearance (CrCl) into 4 groups: group 1 (CrCl >60 mL/min), group 2 (CrCl 60-30 mL/min), group 3 (CrCl <30 mL/min), and group 4 (intermittent hemodialysis). Retrospective chart review was performed to quantify the post milrinone hemodynamic changes by cardiac catheterization and electrophysiologic changes by implantable cardiac defibrillator (ICD) interrogation. A total of 29 patients were identified: group 1 (n=14), group 2 (n=10), group 3(n=3), and group 4 (n = 2). The mean infusion rate (0.391+0.08 mg/kg/min) did not differ between groups (P=0.14). The mean milrinone concentration was 451+243 ng/mL in group 1, 591+293 ng/mL in group 2, 1575+962 ng/mL in group 3, and 6252+4409 ng/mL in group 4 (P<0.05 compared to groups 1). There was no difference in post milrinone hemodynamic improvements between the groups (P=0.41). The ICD interrogation revealed limited comparisons, but 6 of the 8 post milrinone ventricular tachycardia episodes requiring defibrillation occurred in group 4 patients. Patients with stage D HF having severe renal dysfunction have elevated milrinone concentrations. Future studies of milrinone concentrations are warranted to investigate the potential risk of life-threatening arrhythmias and potential dosing regimens in renal dysfunction.

Computational representation and hemodynamic characterization of in vivo acquired severe stenotic renal artery geometries using turbulence modeling.

PubMed

Kagadis, George C; Skouras, Eugene D; Bourantas, George C; Paraskeva, Christakis A; Katsanos, Konstantinos; Karnabatidis, Dimitris; Nikiforidis, George C

2008-06-01

The present study reports on computational fluid dynamics in the case of severe renal artery stenosis (RAS). An anatomically realistic model of a renal artery was reconstructed from CT scans, and used to conduct CFD simulations of blood flow across RAS. The recently developed shear stress transport (SST) turbulence model was pivotally applied in the simulation of blood flow in the region of interest. Blood flow was studied in vivo under the presence of RAS and subsequently in simulated cases before the development of RAS, and after endovascular stent implantation. The pressure gradients in the RAS case were many orders of magnitude larger than in the healthy case. The presence of RAS increased flow resistance, which led to considerably lower blood flow rates. A simulated stent in place of the RAS decreased the flow resistance at levels proportional to, and even lower than, the simulated healthy case without the RAS. The wall shear stresses, differential pressure profiles, and net forces exerted on the surface of the atherosclerotic plaque at peak pulse were shown to be of relevant high distinctiveness, so as to be considered potential indicators of hemodynamically significant RAS.

Cellular transport of l-arginine determines renal medullary blood flow in control rats, but not in diabetic rats despite enhanced cellular uptake capacity.

PubMed

Persson, Patrik; Fasching, Angelica; Teerlink, Tom; Hansell, Peter; Palm, Fredrik

2017-02-01

Diabetes mellitus is associated with decreased nitric oxide bioavailability thereby affecting renal blood flow regulation. Previous reports have demonstrated that cellular uptake of l-arginine is rate limiting for nitric oxide production and that plasma l-arginine concentration is decreased in diabetes. We therefore investigated whether regional renal blood flow regulation is affected by cellular l-arginine uptake in streptozotocin-induced diabetic rats. Rats were anesthetized with thiobutabarbital, and the left kidney was exposed. Total, cortical, and medullary renal blood flow was investigated before and after renal artery infusion of increasing doses of either l-homoarginine to inhibit cellular uptake of l-arginine or N ω -nitro- l-arginine methyl ester (l-NAME) to inhibit nitric oxide synthase. l-Homoarginine infusion did not affect total or cortical blood flow in any of the groups, but caused a dose-dependent reduction in medullary blood flow. l-NAME decreased total, cortical and medullary blood flow in both groups. However, the reductions in medullary blood flow in response to both l-homoarginine and l-NAME were more pronounced in the control groups compared with the diabetic groups. Isolated cortical tubular cells displayed similar l-arginine uptake capacity whereas medullary tubular cells isolated from diabetic rats had increased l-arginine uptake capacity. Diabetics had reduced l-arginine concentrations in plasma and medullary tissue but increased l-arginine concentration in cortical tissue. In conclusion, the reduced l-arginine availability in plasma and medullary tissue in diabetes results in reduced nitric oxide-mediated regulation of renal medullary hemodynamics. Cortical blood flow regulation displays less dependency on extracellular l-arginine and the upregulated cortical tissue l-arginine may protect cortical hemodynamics in diabetes. Copyright © 2017 the American Physiological Society.

Hemodynamics of the renal artery ostia with implications for their structural development and efficiency of flow.

PubMed

McIntosh, William H; Ozturk, Mesude; Down, Linden A; Papavassiliou, Dimitrios V; O'Rear, Edgar A

2015-01-01

Energy losses at tube or blood vessel orifices depend on the extent of flare as measured by the dimensionless ratio of the fillet radius of curvature to diameter (r/D). The goal of this study was to assess the effect of ostial fillet radii on energy losses at the aorta-renal artery junctions since as much as a quarter of cardiac output passes through the kidneys. Pressure loss coefficients K for the renal artery ostia as a function of r/D have been determined for representative anatomical variants using finite volume simulations. Estimates of fillet radii in humans from image analysis were employed in simulations for comparison of loss coefficients. Values for K drop 45% as r/D increases over the range 0-1.3. Image analysis indicates that the ostia are not symmetric in humans with (r/D)superior much larger than (r/D)inferior. Simulations show the loss coefficient depends almost entirely on the superior fillet radius. Superior fillet radii for both renal arteries are similar to the optimal value to reduce energy losses while the inferior radii are not. Ostial asymmetry may have been induced by higher levels of shear stress present on the superior portion of a developing symmetric ostium of small r/D.

Contemporary evaluation and management of renal trauma.

PubMed

Chouhan, Jyoti D; Winer, Andrew G; Johnson, Christina; Weiss, Jeffrey P; Hyacinthe, Llewellyn M

2016-04-01

Renal trauma occurs in approximately 1%-5% of all trauma cases. Improvements in imaging and management over the last two decades have caused a shift in the treatment of this clinical condition. A systematic search of PubMed was performed to identify relevant and contemporary articles that referred to the management and evaluation of renal trauma. Computed tomography remains a mainstay of radiological evaluation in hemodynamically stable patients. There is a growing body of literature showing that conservative, non-operative management of renal trauma is safe, even for Grade IV-V renal injuries. If surgical exploration is planned due to other injuries, a conservative approach to the kidney can often be utilized. Follow up imaging may be warranted in certain circumstances. Urinoma, delayed bleeding, and hypertension are complications that require follow up. Appropriate imaging and conservative approaches are a mainstay of current renal trauma management.

Baroreflex activation therapy in patients with prior renal denervation.

PubMed

Wallbach, Manuel; Halbach, Marcel; Reuter, Hannes; Passauer, Jens; Lüders, Stephan; Böhning, Enrico; Zenker, Dieter; Müller, Gerhard A; Wachter, Rolf; Koziolek, Michael J

2016-08-01

Both baroreflex activation therapy (BAT) and renal denervation modulate sympathetic activity. The aim of this study was to systematically investigate whether additive modulation of autonomic nervous system by BAT lowers blood pressure (BP) in patients who still suffer from uncontrolled resistant hypertension despite prior renal denervation. From 2012 to January 2015, patients treated with BAT for uncontrolled resistant hypertension, who prior received renal denervation were consecutively analyzed in four German centers for hypertension. Analyses of office BP, 24-h ambulatory BP, central hemodynamics, parameters of renal function were performed. A total of 28 patients, who underwent renal denervation at least 5 months before and still suffer from uncontrolled BP, were subsequently treated with BAT. The office SBP decreased from 182 ± 28 to 163 ± 27 mmHg (P < 0.01) with a responder rate of 68% (office SBP reduction ≥10 mmHg) at month 6, whereas the number of prescribed antihypertensive drug classes remained unchanged (6.2 ± 1.5 vs. 6.0 ± 1.7, P = 0.30). Serum creatinine, estimated glomerular filtration rate and cystatin C remained stable (P = 1.00, P = 0.41 and P = 0.22, respectively), whereas albuminuria was significantly reduced by a median of -29% (P = 0.02). Central SBP (-15 ± 24 mmHg, P = 0.047) and end systolic pressure (-14 ± 20 mmHg, P = 0.03) were significantly reduced. The present data demonstrate that BAT may exert BP-lowering as well as antiproteinuric effects in patients with prior renal denervation. However, precise evaluation of BAT effects in patients with prior renal denervation will need randomized controlled trials using sham procedures.

Polymyxin B Nephrotoxicity: From Organ to Cell Damage

PubMed Central

Pessoa, Edson Andrade

2016-01-01

Polymyxins have a long history of dose-limiting toxicity, but the underlying mechanism of polymyxin B-induced nephrotoxicity is unclear. This study investigated the link between the nephrotoxic effects of polymyxin B on renal metabolic functions and mitochondrial morphology in rats and on the structural integrity of LLC-PK1 cells. Fifteen Wistar rats were divided into two groups: Saline group, rats received 3 mL/kg of 0.9% NaCl intraperitoneally (i.p.) once a day for 5 days; Polymyxin B group, rats received 4 mg/kg/day of polymyxin B i.p. once a day for 5 days. Renal function, renal hemodynamics, oxidative stress, mitochondrial injury and histological characteristics were assessed. Cell membrane damage was evaluated via lactate dehydrogenase and nitric oxide levels, cell viability, and apoptosis in cells exposed to 12.5 μM, 75 μM and 375 μM polymyxin B. Polymyxin B was immunolocated using Lissamine rhodamine-polymyxin B in LLC-PK1 cells. Polymyxin B administration in rats reduced creatinine clearance and increased renal vascular resistance and oxidative damage. Mitochondrial damage was confirmed by electron microscopy and cytosolic localization of cytochrome c. Histological analysis revealed tubular dilatation and necrosis in the renal cortex. The reduction in cell viability and the increase in apoptosis, lactate dehydrogenase levels and nitric oxide levels confirmed the cytotoxicity of polymyxin B. The incubation of LLC-PK1 cells resulted in mitochondrial localization of polymyxin B. This study demonstrates that polymyxin B nephrotoxicity is characterized by mitochondrial dysfunction and free radical generation in both LLC-PK1 cells and rat kidneys. These data also provide support for clinical studies on the side effects of polymyxin B. PMID:27532263

Aortic Blood Flow Reversal Determines Renal Function: Potential Explanation for Renal Dysfunction Caused by Aortic Stiffening in Hypertension.

PubMed

Hashimoto, Junichiro; Ito, Sadayoshi

2015-07-01

Aortic stiffness determines the glomerular filtration rate (GFR) and predicts the progressive decline of the GFR. However, the underlying pathophysiological mechanism remains obscure. Recent evidence has shown a close link between aortic stiffness and the bidirectional (systolic forward and early diastolic reverse) flow characteristics. We hypothesized that the aortic stiffening-induced renal dysfunction is attributable to altered central flow dynamics. In 222 patients with hypertension, Doppler velocity waveforms were recorded at the proximal descending aorta to calculate the reverse/forward flow ratio. Tonometric waveforms were recorded to measure the carotid-femoral (aortic) and carotid-radial (peripheral) pulse wave velocities, to estimate the aortic pressure from the radial waveforms, and to compute the aortic characteristic impedance. In addition, renal hemodynamics was evaluated by duplex ultrasound. The estimated GFR was inversely correlated with the aortic pulse wave velocity, reverse/forward flow ratio, pulse pressure, and characteristic impedance, whereas it was not correlated with the peripheral pulse wave velocity or mean arterial pressure. The association between aortic pulse wave velocity and estimated GFR was independent of age, diabetes mellitus, hypercholesterolemia, and antihypertensive medication. However, further adjustment for the aortic reverse/forward flow ratio and pulse pressure substantially weakened this association, and instead, the reverse/forward flow ratio emerged as the strongest determinant of estimated GFR (P=0.001). A higher aortic reverse/forward flow ratio was also associated with lower intrarenal forward flow velocities. These results suggest that an increase in aortic flow reversal (ie, retrograde flow from the descending thoracic aorta toward the aortic arch), caused by aortic stiffening and impedance mismatch, reduces antegrade flow into the kidney and thereby deteriorates renal function. © 2015 American Heart Association, Inc.

Diabetes and kidney disease: the role of sodium-glucose cotransporter-2 (SGLT-2) and SGLT-2 inhibitors in modifying disease outcomes.

PubMed

Mende, Christian W

2017-03-01

Patients with type 2 diabetes (T2D) often have coexisting chronic kidney disease (CKD). However, healthy renal function is crucial in maintaining glucose homeostasis, assuring that almost all of the filtered glucose is reabsorbed by the sodium glucose cotransporters (SGLTs) SGLT-1 and SGLT-2. In diabetes, an increased amount of glucose is filtered by the kidneys and SGLT-2 is upregulated, leading to increased glucose absorption and worsening hyperglycemia. Prolonged hyperglycemia contributes to the development of CKD by inducing metabolic and hemodynamic changes in the kidneys. Due to the importance of SGLT-2 in regulating glucose levels, investigation into SGLT-2 inhibitors was initiated as a glucose-dependent mechanism to control hyperglycemia, and there are three agents currently approved for use in the United States: dapagliflozin, canagliflozin, and empagliflozin. SGLT-2 inhibitors have been shown to reduce glycated hemoglobin (A1C), weight, and blood pressure, which not only affects glycemic control, but may also help slow the progression of renal disease by impacting the underlying mechanisms of kidney injury. In addition, SGLT-2 inhibitors have shown reductions in albuminuria, uric acid, and an increase in magnesium. Caution is advised when prescribing SGLT-2 inhibitors to patients with moderately impaired renal function and those at risk for volume depletion and hypotension. Published data on slowing of the development, as well as progression of CKD, is a hopeful indicator for the possible renal protection potential of this drug class. This narrative review provides an in-depth discussion of the interplay between diabetes, SGLT-2 inhibitors, and factors that affect kidney function.

Tumor necrosis factor-α, kidney function, and hypertension.

PubMed

Mehaffey, Eamonn; Majid, Dewan S A

2017-10-01

Hypertension is considered to be a low-grade inflammatory condition characterized by the presence of various proinflammatory cytokines. Tumor necrosis factor-α (TNF-α) is a constituent of the proinflammatory cytokines that is associated with salt-sensitive hypertension (SSH) and related renal injury. Elevated angiotensin II (ANG II) and other factors such as oxidative stress conditions promote TNF-α formation. Many recent studies have provided evidence that TNF-α exerts a direct renal action by regulating hemodynamic and excretory function in the kidney. The cytokine incites a strong natriuretic response and plays a part in regulation of the intrarenal renin-angiotensin system. The exact mechanistic role of TNF-α in the development of SSH is as yet poorly understood. While TNF-α antagonism has been shown to attenuate hypertensive responses in many hypertensive animal models, contrasting findings demonstrate that the direct systemic administration of TNF-α usually induces hypotensive as well as natriuretic responses, indicating a counterregulatory role of TNF-α in SSH. Differential activities of two cell surface receptors of TNF-α (receptor type 1 and type 2) may explain the contradictory functions of TNF-α in the setting of hypertension. This short review will evaluate ongoing research studies that investigate the action of TNF-α within the kidney and its role as an influential pathophysiological variable in the development of SSH and renal injury. This information may help to develop specific TNF-α receptor targeting as an effective treatment strategy in this clinical condition. Copyright © 2017 the American Physiological Society.

Treatment of post-cardiopulmonary bypass SIRS by hemoadsorption: a case series.

PubMed

Träger, Karl; Fritzler, Daniel; Fischer, Guenther; Schröder, Janpeter; Skrabal, Christian; Liebold, Andreas; Reinelt, Helmut

2016-05-16

The use of cardiopulmonary bypass (CPB) in cardiothoracic surgery results in a well-known activation of the immunologic response. In some cases, however, this triggered immunologic response may be excessive, leading to a severe systemic inflammatory response syndrome (SIRS) and induced organ dysfunction. For example, patients frequently develop hemodynamic instability with hypotension and low systemic vascular resistance. To date, different therapeutic approaches, such as steroids, have been tried to control this maladaptive postoperative SIRS response, yet definitive proof of clinical efficacy is missing. A new cytokine adsorber device (CytoSorb; CytoSorbents) may be a useful approach to control hyperinflammatory systemic reactions by reducing a broad range of proinflammatory cytokines and other inflammatory mediators. This may, in turn, help to reestablish a physiologic immune response and help to restore deranged clinical parameters in these patients. In this retrospective case series study, we describe 16 cardiac surgery patients following prolonged CPB with post-CPB SIRS and subsequent acute kidney injury, who were then treated with hemoadsorption using CytoSorb in combination with continuous renal replacement therapy (CRRT). Treatment of patients with CytoSorb who presented with severe post-CPB SIRS resulted in a reduction of elevated cytokine levels, which was associated with a clear stabilization of deranged hemodynamic, metabolic, and organ function parameters. Treatment was well tolerated and safe, with no device-related adverse events occurring. CytoSorb therapy combined with CRRT is a potentially promising new treatment approach to achieve hemodynamic stability, cytokine reduction, and improved organ function in cardiac surgery patients who develop post-CPB SIRS.

First-in-Man Demonstration of Direct Endothelin-Mediated Natriuresis and Diuresis

PubMed Central

Hunter, Robert W.; Moorhouse, Rebecca; Farrah, Tariq E.; MacIntyre, Iain M.; Asai, Takae; Gallacher, Peter J.; Kerr, Debbie; Melville, Vanessa; Czopek, Alicja; Morrison, Emma E.; Ivy, Jess R.; Dear, James W.; Bailey, Matthew A.; Goddard, Jane; Webb, David J.

2017-01-01

Endothelin (ET) receptor antagonists are potentially novel therapeutic agents in chronic kidney disease and resistant hypertension, but their use is complicated by sodium and water retention. In animal studies, this side effect arises from ETB receptor blockade in the renal tubule. Previous attempts to determine whether this mechanism operates in humans have been confounded by the hemodynamic consequences of ET receptor stimulation/blockade. We aimed to determine the effects of ET signaling on salt transport in the human nephron by administering subpressor doses of the ET-1 precursor, big ET-1. We conducted a 2-phase randomized, double-blind, placebo-controlled crossover study in 10 healthy volunteers. After sodium restriction, subjects received either intravenous placebo or big ET-1, in escalating dose (≤300 pmol/min). This increased plasma concentration and urinary excretion of ET-1. Big ET-1 reduced heart rate (≈8 beats/min) but did not otherwise affect systemic hemodynamics or glomerular filtration rate. Big ET-1 increased the fractional excretion of sodium (from 0.5 to 1.0%). It also increased free water clearance and tended to increase the abundance of the sodium–potassium–chloride cotransporter (NKCC2) in urinary extracellular vesicles. Our protocol induced modest increases in circulating and urinary ET-1. Sodium and water excretion increased in the absence of significant hemodynamic perturbation, supporting a direct action of ET-1 on the renal tubule. Our data also suggest that sodium reabsorption is stimulated by ET-1 in the thick ascending limb and suppressed in the distal renal tubule. Fluid retention associated with ET receptor antagonist therapy may be circumvented by coprescribing potassium-sparing diuretics. PMID:28507171

Splanchnic and renal deterioration during and after laparoscopic cholecystectomy: a comparison of the carbon dioxide pneumoperitoneum and the abdominal wall lift method.

PubMed

Koivusalo, A M; Kellokumpu, I; Ristkari, S; Lindgren, L

1997-10-01

Carbon dioxide (CO2) pneumoperitoneum together with an increased intraabdominal pressure (IAP) induces a hemodynamic stress response, diminishes urine output, and may compromise splanchnic perfusion. A new retractor method may be less traumatic. Accordingly, 30 ASA physical status I or II patients undergoing laparoscopic cholecystectomy were randomly allocated to a CO2 pneumoperitoneum (IAP 12-13 mm Hg) (control) or to a gasless abdominal wall lift method (retractor) group. Anesthesia and intravascular fluids were standardized. Direct mean arterial pressure (MAP), urine output, urine-N-acetyl-beta-D-glucosaminidase (U-NAG), arterial blood gases, gastric mucosal PCO2, and intramucosal pH (pHi) were measured. Normoventilation was instituted in all patients. MAP increased (P < 0.001) only with CO2 pneumoperitoneum. Minute volume of ventilation had to be increased by 35% with CO2 insufflation. PaCO2 was significantly higher (P < 0.05) for 3 h postoperatively in the control group. Diuresis was less (P < 0.01) and U-NAG levels (P < 0.01) higher in the control group. The pHi decreased after induction of pneumoperitoneum up to three hours postoperatively and remained intact in the retractor group. We conclude that the retractor method for laparoscopic cholecystectomy ensures stable hemodynamics, prevents respiratory acidosis, and provides protection against biochemical effects, which reveal the renal and splanchic ischemia caused by CO2 insufflation. A mechanical retractor method (gasless) was compared with conventional CO2 pneumoperitoneum for laparoscopic cholestectomy. The gasless method ensured stable hemodynamics, prevented respiratory acidosis, and provided protection against the renal and splanchnic ischemia seen with CO2 pneumoperitoneum.

Anatomic and hemodynamic evaluation of renal venous flow in varicocele formation using color Doppler sonography with emphasis on renal vein entrapment syndrome.

PubMed

Unlu, Murat; Orguc, Sebnem; Serter, Selim; Pekindil, Gokhan; Pabuscu, Yuksel

2007-01-01

To investigate the anatomic and hemodynamic properties of testicular venous drainage and its effects on varicocele formation and reflux using color Doppler ultrasound (US) with emphasis on renal vein entrapment syndrome. Upper abdominal and scrotal US examinations of 35 varicocele patients and 35 healthy male subjects were performed in the supine position during rest, during a Valsalva maneuver and in the erect position. The aortomesenteric angle and distance (AMA and AMD, respectively), peak mean velocities (PVs) and diameters of different segments of renal veins, testicular vein diameters and duration of flow inversion were measured. In the varicocele group, the lateral segment of the left renal vein (LRV) had a larger diameter and slower PV, and the medial segment of the LRV had a smaller diameter and faster PV. The diameter of the dominant draining vein correlated with the PV of the medial and lateral segments of the LRV, whereas there was no correlation between the diameter of the dominant draining vein and the diameters of the right renal vein (RRV) and the lateral segment of the LRV or the PV of the RRV. The duration of flow inversion correlated with the diameter and PV of the medial segment of the LRV. No correlation between the diameters and PVs of the RRV and the lateral segment of the LRV was detected. The decreases in the AMA, AMD, diameter of the medial segment of the LRV and PV of the lateral segment of the LRV, and the increases in the PV of the medial segment of the LRV and the diameter of the lateral segment of the LRV in varicocele patients in all positions suggest the entrapment or impingement of the left renal vein between the aorta and the superior mesenteric artery. This has been defined as the "nutcracker phenomenon", which is known to affect varicocele formation.

Effect of exercise on hemodynamic conditions in the abdominal aorta.

PubMed

Taylor, C A; Hughes, T J; Zarins, C K

1999-06-01

The beneficial effect of exercise in the retardation of the progression of cardiovascular disease is hypothesized to be caused, at least in part, by the elimination of adverse hemodynamic conditions, including flow recirculation and low wall shear stress. In vitro and in vivo investigations have provided qualitative and limited quantitative information on flow patterns in the abdominal aorta and on the effect of exercise on the elimination of adverse hemodynamic conditions. We used computational fluid mechanics methods to examine the effects of simulated exercise on hemodynamic conditions in an idealized model of the human abdominal aorta. A three-dimensional computer model of a healthy human abdominal aorta was created to simulate pulsatile aortic blood flow under conditions of rest and graded exercise. Flow velocity patterns and wall shear stress were computed in the lesion-prone infrarenal aorta, and the effects of exercise were determined. A recirculation zone was observed to form along the posterior wall of the aorta immediately distal to the renal vessels under resting conditions. Low time-averaged wall shear stress was present in this location, along the posterior wall opposite the superior mesenteric artery and along the anterior wall between the superior and inferior mesenteric arteries. Shear stress temporal oscillations, as measured with an oscillatory shear index, were elevated in these regions. Under simulated light exercise conditions, a region of low wall shear stress and high oscillatory shear index remained along the posterior wall immediately distal to the renal arteries. Under simulated moderate exercise conditions, all the regions of low wall shear stress and high oscillatory shear index were eliminated. This numeric investigation provided detailed quantitative data on the effect of exercise on hemodynamic conditions in the abdominal aorta. Our results indicated that moderate levels of lower limb exercise are necessary to eliminate the flow reversal and regions of low wall shear stress in the abdominal aorta that exist under resting conditions. The lack of flow reversal and increased wall shear stress during exercise suggest a mechanism by which exercise may promote arterial health, namely with the elimination of adverse hemodynamic conditions.

Renal angioplasty and stenting: is it still indicated after ASTRAL and STAR studies?

PubMed

Henry, M; Benjelloun, A; Henry, I; Polydorou, A; Hugel, M

2010-10-01

A renal artery stenosis (RAS) is common among patients with atherosclerosis, up to a third of patients undergoing cardiac catheterization. Fibromuscular dysplasia is the next cause of RAS, commonly found in young women. Atherosclerosis RAS generally progresses overtime and is often associated with loss of renal mass and worsening renal function (RF). Percutaneous renal artery stent placement is the preferred method of revascularization for hemodynamically significant RAS according to ACC and AHA guidelines. Several randomized trials have shown the superiority of endovascular procedures to medical therapy alone. However, two studies ASTRAL and STAR studies were recently published and did not find any difference between renal stenting and medical therapy. But these studies have a lot of limitations and flaws as we will discuss (poor indications, poor results, numerous complications, failures, poor technique, inexperienced operators, ecc.). Despite these questionable studies, renal stenting keeps indications in patients with: uncontrolled hypertension; ischemic nephropathy; cardiac disturbance syndrome (e.g. "flash" pulmonary edema, uncontrolled heart failure or uncontrolled angina pectoris); solitary kidney. To improve the clinical response rates, a better selection of the patients and lesions is mandatory with: good non-invasive or invasive imaging; physiologic lesion assessment using transluminal pressure gradients; measurements of biomarkers (e.g., BNP); fractional flow reserve study. A problem remains after renal angioplasty stenting, the deterioration of the RF in 20-30% of the patients. Atheroembolism seems to play an important role and is probably the main cause of this R.F deterioration. The use of protection devices alone or in combination with IIb IIa inhibitors has been proposed and seems promising as shown in different recent reports. Renal angioplasty and stenting is still indicated but we need: a better patient and lesion selection; improvements in techniques and maybe the use of protection devices to reduce the risk of RF deterioration after renal stenting.

Effects of water immersion on renal hemodynamics in normal man

NASA Technical Reports Server (NTRS)

Epstein, M.; Levinson, R.; Loutzenhiser, R.

1976-01-01

The present study was undertaken to delineate the effects of water immersion to the neck (NI) on renal plasma flow and glomerular filtration rate as assessed by the clearance of p-aminohippuric acid (PAH) and inulin, respectively. Nine normal male subjects were studied on two occasions, control and NI. The conditions of seated posture and time of day were identical. Immersion did not alter either clearance at a time when sodium excretion was increasing markedly. The constancy of PAH clearance during NI suggests that renal blood flow is unaltered and that the natriuresis of NI is mediated independently of alterations in overall renal perfusion. The sluggish decline of a natriuresis during recovery is consistent with the presence of a humoral factor contributing to the encountered natriuresis.

ALDOSTERONE DYSREGULATION WITH AGING PREDICTS RENAL-VASCULAR FUNCTION AND CARDIO-VASCULAR RISK

PubMed Central

Brown, Jenifer M.; Underwood, Patricia C.; Ferri, Claudio; Hopkins, Paul N.; Williams, Gordon H.; Adler, Gail K.; Vaidya, Anand

2014-01-01

Aging and abnormal aldosterone regulation are both associated with vascular disease. We hypothesized that aldosterone dysregulation influences the age-related risk of renal- and cardio-vascular disease. We conducted an analysis of 562 subjects who underwent detailed investigations under conditions of liberal and restricted dietary sodium intake (1,124 visits) in a Clinical Research Center. Aldosterone regulation was characterized by the ratio of maximal suppression-to-stimulation (supine serum aldosterone on a liberal sodium diet divided by the same measure on a restricted sodium diet). We previously demonstrated that higher levels of this Sodium-modulated Aldosterone Suppression-Stimulation Index (SASSI) indicate greater aldosterone dysregulation. Renal plasma flow (RPF) was determined via p-aminohippurate clearance to assess basal renal hemodynamics, and the renal-vascular responses to dietary sodium manipulation and angiotensin II (AngII) infusion. Cardiovascular risk was calculated using the Framingham Risk Score. In univariate linear regression, older age (β= -4.60, p<0.0001) and higher SASSI (β= -58.63, p=0.001) predicted lower RPF and a blunted RPF response to sodium loading and AngII infusion. We observed a continuous, independent, multivariate-adjusted interaction between age and SASSI, where the inverse relationship between SASSI and RPF was most apparent with older age (p<0.05). Higher SASSI and lower RPF independently predicted higher Framingham Risk Score (p<0.0001) and together displayed an additive effect. Aldosterone regulation and age may interact to mediate renal-vascular disease. Our findings suggest that the combination of aldosterone dysregulation and renal-vascular dysfunction could additively increase the risk of future cardiovascular outcomes; therefore, aldosterone dysregulation may represent a modifiable mechanism of age-related vascular disease. PMID:24664291

Aldosterone dysregulation with aging predicts renal vascular function and cardiovascular risk.

PubMed

Brown, Jenifer M; Underwood, Patricia C; Ferri, Claudio; Hopkins, Paul N; Williams, Gordon H; Adler, Gail K; Vaidya, Anand

2014-06-01

Aging and abnormal aldosterone regulation are both associated with vascular disease. We hypothesized that aldosterone dysregulation influences the age-related risk of renal vascular and cardiovascular disease. We conducted an analysis of 562 subjects who underwent detailed investigations under conditions of liberal and restricted dietary sodium intake (1124 visits) in the General Clinical Research Center. Aldosterone regulation was characterized by the ratio of maximal suppression to stimulation (supine serum aldosterone on a liberal sodium diet divided by the same measure on a restricted sodium diet). We previously demonstrated that higher levels of this Sodium-modulated Aldosterone Suppression-Stimulation Index (SASSI) indicate greater aldosterone dysregulation. Renal plasma flow (RPF) was determined via p-aminohippurate clearance to assess basal renal hemodynamics and the renal vascular responses to dietary sodium manipulation and angiotensin II infusion. Cardiovascular risk was calculated using the Framingham Risk Score. In univariate linear regression, older age (β=-4.60; P<0.0001) and higher SASSI (β=-58.63; P=0.001) predicted lower RPF and a blunted RPF response to sodium loading and angiotensin II infusion. We observed a continuous, independent, multivariate-adjusted interaction between age and SASSI, where the inverse relationship between SASSI and RPF was most apparent with older age (P<0.05). Higher SASSI and lower RPF independently predicted higher Framingham Risk Score (P<0.0001) and together displayed an additive effect. Aldosterone regulation and age may interact to mediate renal vascular disease. Our findings suggest that the combination of aldosterone dysregulation and renal vascular dysfunction could additively increase the risk of future cardiovascular outcomes; therefore, aldosterone dysregulation may represent a modifiable mechanism of age-related vascular disease.

Vascular Smooth Muscle-Specific EP4 Receptor Deletion in Mice Exacerbates Angiotensin II-Induced Renal Injury.

PubMed

Thibodeau, Jean-Francois; Holterman, Chet E; He, Ying; Carter, Anthony; Cron, Gregory O; Boisvert, Naomi C; Abd-Elrahman, Khaled S; Hsu, Karolynn J; Ferguson, Stephen S G; Kennedy, Christopher R J

2016-10-20

Cyclooxygenase inhibition by non-steroidal anti-inflammatory drugs is contraindicated in hypertension, as it may reduce glomerular filtration rate (GFR) and renal blood flow. However, the identity of the specific eicosanoid and receptor underlying these effects is not known. We hypothesized that vascular smooth muscle prostaglandin E2 (PGE2) E-prostanoid 4 (EP4) receptor deletion predisposes to renal injury via unchecked vasoconstrictive actions of angiotensin II (AngII) in a hypertension model. Mice with inducible vascular smooth muscle cell (VSMC)-specific EP4 receptor deletion were generated and subjected to AngII-induced hypertension. EP4 deletion was verified by PCR of aorta and renal vessels, as well as functionally by loss of PGE2-mediated mesenteric artery relaxation. Both AngII-treated groups became similarly hypertensive, whereas albuminuria, foot process effacement, and renal hypertrophy were exacerbated in AngII-treated EP4 VSMC-/- but not in EP4 VSMC+/+ mice and were associated with glomerular scarring, tubulointerstitial injury, and reduced GFR. AngII-treated EP4 VSMC-/- mice exhibited capillary damage and reduced renal perfusion as measured by fluorescent bead microangiography and magnetic resonance imaging, respectively. NADPH oxidase 2 (Nox2) expression was significantly elevated in AngII-treated EP4 -/- mice. EP4-receptor silencing in primary VSMCs abolished PGE2 inhibition of AngII-induced Nox2 mRNA and superoxide production. These data suggest that vascular EP4 receptors buffer the actions of AngII on renal hemodynamics and oxidative injury. EP4 agonists may, therefore, protect against hypertension-associated kidney damage. Antioxid. Redox Signal. 25, 642-656.

Obesity-related glomerulopathy: pathogenesis, pathologic, clinical characteristics and treatment.

PubMed

Xu, Tianhua; Sheng, Zitong; Yao, Li

2017-09-01

In light of the rapid increase in the number of obesity incidences worldwide, obesity has become an independent risk factor for chronic kidney disease. Obesity-related glomerulopathy (ORG) is characterized by glomerulomegaly in the presence or absence of focal and segmental glomerulosclerosis lesions. IgM and complement 3 (C3) nonspecifically deposit in lesions without immune-complex-type deposits during ORG immunofluorescence. ORG-associated glomerulomegaly and focal and segmental glomerulosclerosis can superimpose on other renal pathologies. The mechanisms under ORG are complex, especially hemodynamic changes, inflammation, oxidative stress, apoptosis, and reduced functioning nephrons. These mechanisms synergize with obesity to induce end-stage renal disease. A slow increase of subnephrotic proteinuria ( < 3.5 g/d) is the most common clinical manifestation of ORG. Several treatment methods for ORG have been developed. Of these methods, renin-angiotensin-aldosterone system blockade and weight loss are proven effective. Targeting mitochondria may offer a novel strategy for ORG therapy. Nevertheless, more research is needed to further understand ORG.

The evolving landscape of RAAS inhibition: from ACE inhibitors to ARBs, to DRIs and beyond.

PubMed

Epstein, Benjamin J; Leonard, Paul T; Shah, Niren K

2012-06-01

Chronic renin-angiotensin-aldosterone system (RAAS) activation has far-reaching effects on cardiometabolic risk and is a substantial contributor to cardiovascular (CV) disease and renal dysfunction. The vascular effects of sustained RAAS activation are associated with hemodynamic imbalances, as well as inflammatory stimulation and prothrombotic processes that lead to fibrosis, endothelial dysfunction and cellular remodeling. RAAS inhibition therapies, which include the use of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and more recently, direct renin inhibitors, have been used in clinical practice for more than 30 years. Our understanding of how these drugs work, alone and in combination, has contributed to an expanding landscape of treatment options and established RAAS inhibition as essential for reducing the risk of CV and renal disease. This perspective provides a historical overview of how RAAS inhibitors have evolved to their present-day status and will discuss recently discovered functions for components of this complicated and powerful regulatory system.

Pre-clinical longitudinal monitoring of hemodynamic response to anti-vascular chemotherapy by hybrid diffuse optics.

PubMed

Farzam, Parisa; Johansson, Johannes; Mireles, Miguel; Jiménez-Valerio, Gabriela; Martínez-Lozano, Mar; Choe, Regine; Casanovas, Oriol; Durduran, Turgut

2017-05-01

The longitudinal effect of an anti-vascular endothelial growth factor receptor 2 (VEGFR-2) antibody (DC 101) therapy on a xenografted renal cell carcinoma (RCC) mouse model was monitored using hybrid diffuse optics. Two groups of immunosuppressed male nude mice (seven treated, seven controls) were measured. Tumor microvascular blood flow, total hemoglobin concentration and blood oxygenation were investigated as potential biomarkers for the monitoring of the therapy effect twice a week and were related to the final treatment outcome. These hemodynamic biomarkers have shown a clear differentiation between two groups by day four. Moreover, we have observed that pre-treatment values and early changes in hemodynamics are highly correlated with the therapeutic outcome demonstrating the potential of diffuse optics to predict the therapy response at an early time point.

Nursing issues in renal replacement therapy: organization, manpower assessment, competency evaluation and quality improvement processes.

PubMed

Graham, Patricia; Lischer, Eileen

2011-01-01

For the patient with acute kidney injury, continuous renal replacement therapy (CRRT) is a treatment option that has application for the hemodynamically unstable critically ill patient. The decision to initiate a continuous renal replacement modality depends not only on the physician, either the nephrologist or intensivist, but also on the availability of specially trained nursing resources. This article will explore the nursing collaborative model of care at a large university-based research and teaching Medical Center in Southern California. The focus will be on nursing issues in CRRT including organization of educational programs, manpower assessment, competency evaluation, and quality improvement processes. © 2011 Wiley Periodicals, Inc.

Angiographic Findings and Embolotherapy in Renal Arterial Trauma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sofocleous, Constantinos T., E-mail: constant@pol.net; Hinrichs, Clay; Hubbi, Basil

Purpose To evaluate the angiographic findings and embolotherapy in the management of traumatic renal arterial injury Methods This is a retrospective review of 22 patients with renal trauma who underwent arteriography and percutaneous embolization from December 1995 to January 2002. Medical records, imaging studies and procedural reports were reviewed to assess the type of injury, arteriographic findings and immediate embolization results. Long-term clinical outcome was obtained by communication with the trauma physicians and by clinical chart review.Results Arteriography was performed in 125 patients admitted to a State Trauma Center with suspected internal bleeding. Renal arterial injury was documented in 22more » and was the result of a motor-vehicle accident (10), auto-pedestrian accident (1), gunshot (4) or stab wounds (6) and a fall (1). Percutaneous renal arterial embolization was undertaken in 22 of 125 (18%) patients to treat extravasation (11), arterial pedicle rupture (5), abnormal arteriovenous (3) or arteriocalyceal (2) communication and pseudoaneurysm (3). One of the pseudoaneurysms and one of the arteriovenous fistulae were found in addition to extravasation. All 22 patients (16 men, 6 women) were hemodynamically stable, or controlled during arteriography and embolotherapy. Selective and/or superselective embolization of the abnormal vessels was performed using coils in 9 patients, microcoils in 9 patients and Gelfoam pledgets in 3 patients. In one patient Gelfoam pledgets mixed with polyvinyl alcohol (PVA) particles were used for embolization. Immediate angiographic evidence of hemostasis was demonstrated in all cases. Two initial technical failures were treated with repeat arteriography and embolization. There was no procedure-related death. There was no non-target embolization. One episode of renal abscess after embolization was treated by nephrectomy and 3 patients underwent elective post-embolization nephrectomy to prevent infection. Follow-up ranged from 1 month to 7 years (mean 31 months). No procedure-related or delayed onset of renal insufficiency occurred.Conclusion In hemodynamically stable and controlled patients selective and superselective embolization is a safe and effective method for the management of renal vascular injury.« less

Sorting Nexin 1 Loss Results in D5 Dopamine Receptor Dysfunction in Human Renal Proximal Tubule Cells and Hypertension in Mice*

PubMed Central

Villar, Van Anthony M.; Jones, John Edward; Armando, Ines; Asico, Laureano D.; Escano, Crisanto S.; Lee, Hewang; Wang, Xiaoyan; Yang, Yu; Pascua-Crusan, Annabelle M.; Palmes-Saloma, Cynthia P.; Felder, Robin A.; Jose, Pedro A.

2013-01-01

The peripheral dopaminergic system plays a crucial role in blood pressure regulation through its actions on renal hemodynamics and epithelial ion transport. The dopamine D5 receptor (D5R) interacts with sorting nexin 1 (SNX1), a protein involved in receptor retrieval from the trans-Golgi network. In this report, we elucidated the spatial, temporal, and functional significance of this interaction in human renal proximal tubule cells and HEK293 cells stably expressing human D5R and in mice. Silencing of SNX1 expression via RNAi resulted in the failure of D5R to internalize and bind GTP, blunting of the agonist-induced increase in cAMP production and decrease in sodium transport, and up-regulation of angiotensin II receptor expression, of which expression was previously shown to be negatively regulated by D5R. Moreover, siRNA-mediated depletion of renal SNX1 in C57BL/6J and BALB/cJ mice resulted in increased blood pressure and blunted natriuretic response to agonist in salt-loaded BALB/cJ mice. These data demonstrate a crucial role for SNX1 in D5R trafficking and that SNX1 depletion results in D5R dysfunction and thus may represent a novel mechanism for the pathogenesis of essential hypertension. PMID:23152498

The effects of combined versus selective adrenergic blockade on left ventricular and systemic hemodynamics, myocardial substrate preference, and regional perfusion in conscious dogs with dilated cardiomyopathy.

PubMed

Nikolaidis, Lazaros A; Poornima, Indu; Parikh, Pratik; Magovern, Megan; Shen, You-Tang; Shannon, Richard P

2006-05-02

Given that adverse effects of chronic sympathetic activation are mediated by all three adrenergic receptor subtypes (beta1, beta2, alpha1), we examined the effects of standard doses of carvedilol and metoprolol succinate (metoprolol controlled release/extended release [CR/XL]) on hemodynamics, myocardial metabolism, and regional organ perfusion. Both beta1 selective and combined adrenergic blockade reduce morbidity and mortality in heart failure. Whether there are advantages of one class over the other remains controversial, even in the wake of the Carvedilol Or Metoprolol European Trial (COMET). Similarly, the mechanistic basis for the relative differences is incompletely understood. Thirty-three conscious, chronically instrumented dogs with pacing-induced (240 min(-1) for 4 weeks) dilated cardiomyopathy (DCM) were randomized to carvedilol (25 mg twice daily, Coreg, Glaxo Smith Kline, Research Triangle, North Carolina) or metoprolol succinate (100 mg qd, Toprol XL, Astra Zeneca, Wilmington, Delaware). Left ventricular and systemic hemodynamics, myocardial substrate uptake, and norepinephrine spillover were measured before and after three days of treatment. Regional (renal, hepatic, skeletal muscle) blood flows were measured using neutron-activated microspheres. Both agents had comparable heart rate effects. However, carvedilol-treated dogs showed significantly greater increases in stroke volume and cardiac output and decreases in left ventricular end-diastolic pressure and systemic vascular resistance. Carvedilol increased renal, hepatic, and skeletal muscle blood flow. Carvedilol increased myocardial glucose uptake and suppressed norepinephrine and glucagon. Carvedilol antagonized the response to exogenous norepinephrine to a greater extent than metoprolol CR/XL. At doses inducing comparable heart rate reductions, short-term treatment with carvedilol had superior hemodynamic and metabolic effects compared with metoprolol CR/XL. These data suggest important advantages of blocking all three adrenergic receptor subtypes in DCM.

Clinical Implications of Cluster Analysis-Based Classification of Acute Decompensated Heart Failure and Correlation with Bedside Hemodynamic Profiles.

PubMed

Ahmad, Tariq; Desai, Nihar; Wilson, Francis; Schulte, Phillip; Dunning, Allison; Jacoby, Daniel; Allen, Larry; Fiuzat, Mona; Rogers, Joseph; Felker, G Michael; O'Connor, Christopher; Patel, Chetan B

2016-01-01

Classification of acute decompensated heart failure (ADHF) is based on subjective criteria that crudely capture disease heterogeneity. Improved phenotyping of the syndrome may help improve therapeutic strategies. To derive cluster analysis-based groupings for patients hospitalized with ADHF, and compare their prognostic performance to hemodynamic classifications derived at the bedside. We performed a cluster analysis on baseline clinical variables and PAC measurements of 172 ADHF patients from the ESCAPE trial. Employing regression techniques, we examined associations between clusters and clinically determined hemodynamic profiles (warm/cold/wet/dry). We assessed association with clinical outcomes using Cox proportional hazards models. Likelihood ratio tests were used to compare the prognostic value of cluster data to that of hemodynamic data. We identified four advanced HF clusters: 1) male Caucasians with ischemic cardiomyopathy, multiple comorbidities, lowest B-type natriuretic peptide (BNP) levels; 2) females with non-ischemic cardiomyopathy, few comorbidities, most favorable hemodynamics; 3) young African American males with non-ischemic cardiomyopathy, most adverse hemodynamics, advanced disease; and 4) older Caucasians with ischemic cardiomyopathy, concomitant renal insufficiency, highest BNP levels. There was no association between clusters and bedside-derived hemodynamic profiles (p = 0.70). For all adverse clinical outcomes, Cluster 4 had the highest risk, and Cluster 2, the lowest. Compared to Cluster 4, Clusters 1-3 had 45-70% lower risk of all-cause mortality. Clusters were significantly associated with clinical outcomes, whereas hemodynamic profiles were not. By clustering patients with similar objective variables, we identified four clinically relevant phenotypes of ADHF patients, with no discernable relationship to hemodynamic profiles, but distinct associations with adverse outcomes. Our analysis suggests that ADHF classification using simultaneous considerations of etiology, comorbid conditions, and biomarker levels, may be superior to bedside classifications.

Effects of different durations of sustained inflation during cardiopulmonary resuscitation on return of spontaneous circulation and hemodynamic recovery in severely asphyxiated piglets.

PubMed

Mustofa, J; Cheung, P-Y; Patel, S; Lee, T F; Lu, M; Pasquin, M P; OʼReilly, M; Schmölzer, G M

2018-06-18

We previously demonstrated that sustained inflation (SI) during chest compression (CC) significantly reduces time to return of spontaneous circulation (ROSC) when compared to 3:1 compression:ventilation (C:V) ratio during neonatal resuscitation. However, the optimal length of SI during CC to improve ROSC and hemodynamic recovery in severely asphyxiated piglets is unknown. To examine if different lengths of SI will improve ROSC and hemodynamic recovery in severely asphyxiated piglets. Thirty newborn piglets (1-3 days) were anesthetized, intubated, instrumented and exposed to 30-min normocapnic hypoxia followed by asphyxia. Piglets were randomized into four groups: 3:1 C:V (n = 8), CC with an SI duration of either 20 s (CC+SI 20) (n = 8) or 60 s (CC+SI 60) (n = 8), and a sham group (n = 6). Cardiac function, carotid blood flow, cerebral and renal oxygenation as well as respiratory parameters were continuously recorded throughout the experiment. When compared with 3:1 group, both CC+SI 20 and CC+SI 60 groups had significantly shorter ROSC time (p = 0.002). All three intervention groups had similar hemodynamic recovery by the end of 4 h observation period. There was no difference in lung injury markers among all experimental groups. However, when compared to the sham group, the concentrations of IL-6 (thalamus) and IL-6 + IL-8 (frontoparietal cortex) of the 3:1 C:V group were significantly higher, respectively. Even though relatively less animals achieved ROSC, CC during SI significantly improved ROSC time compared to 3:1 C:V in asphyxiated newborn piglets. However, there was no difference in ROSC characteristics and hemodynamic recovery between two CC+SI groups. Copyright © 2018 Elsevier B.V. All rights reserved.

Modeling of Kidney Hemodynamics: Probability-Based Topology of an Arterial Network.

PubMed

Postnov, Dmitry D; Marsh, Donald J; Postnov, Dmitry E; Braunstein, Thomas H; Holstein-Rathlou, Niels-Henrik; Martens, Erik A; Sosnovtseva, Olga

2016-07-01

Through regulation of the extracellular fluid volume, the kidneys provide important long-term regulation of blood pressure. At the level of the individual functional unit (the nephron), pressure and flow control involves two different mechanisms that both produce oscillations. The nephrons are arranged in a complex branching structure that delivers blood to each nephron and, at the same time, provides a basis for an interaction between adjacent nephrons. The functional consequences of this interaction are not understood, and at present it is not possible to address this question experimentally. We provide experimental data and a new modeling approach to clarify this problem. To resolve details of microvascular structure, we collected 3D data from more than 150 afferent arterioles in an optically cleared rat kidney. Using these results together with published micro-computed tomography (μCT) data we develop an algorithm for generating the renal arterial network. We then introduce a mathematical model describing blood flow dynamics and nephron to nephron interaction in the network. The model includes an implementation of electrical signal propagation along a vascular wall. Simulation results show that the renal arterial architecture plays an important role in maintaining adequate pressure levels and the self-sustained dynamics of nephrons.

The rationale/design of the Guimarães/Vizela study: a multimodal population-based cohort study to determine global cardiovascular risk and disease.

PubMed

Cunha, Pedro Guimarães; Cotter, Jorge; Oliveira, Pedro; Vila, Isabel; Sousa, Nuno

2014-06-01

Cardiovascular disease and dementia are growing medical and social problems in aging societies. Appropriate knowledge of cardiovascular disease and cognitive decline risk factors (RFs) are critical for global CVR health preventive intervention. Many epidemiological studies use case definition based on data collected/measured in a single visit, a fact that can overestimate prevalence rates and distant from clinical practice demanding criteria. Portugal displays an elevated stroke mortality rate. However, population's global CV risk characterization is limited, namely, considering traditional/nontraditional RF and new intermediate phenotypes of CV and renal disease. Association of hemodynamic variables (pulse wave velocity and central blood pressure) with global CVR stratification, cognitive performance, and kidney disease are practically inexistent at a dwelling population level. After reviewing published data, we designed a population-based cohort study to analyze the prevalence of these cardiovascular RFs and intermediate phenotypes, using random sampling of adult dwellers living in 2 adjacent cities. Strict definition of phenotypes was planned: subjects were observed twice, and several hemodynamic and other biological variables measured at least 3 months apart. Three thousand thirty-eight subjects were enrolled, and extensive data collection (including central and peripheral blood pressure, pulse wave velocity), sample processing, and biobank edification were carried out. One thousand forty-seven cognitive evaluations were performed. Seeking for CV risk reclassification, early identification of subjects at risk, and evidence of early vascular aging and cognitive and renal function decline, using the strict daily clinical practice criteria, will lead to better resource allocation in preventive measures at a population level.

Ventricular septal rupture, right ventricular dissection, and tricuspid chordae rupture--A rare complication after inferior and right ventricular infarction.

PubMed

Li, Xiao-hong; Zhao, Ying; Dong, Jianzeng; He, Yihua; Liu, Wenxu; Han, Jiancheng

2015-10-01

A 76-year-old man under stable hemodynamic condition was admitted to our hospital for delayed percutaneous coronary intervention following a diagnosis of acute inferior myocardial infarction. Bedside echocardiography revealed ventricular septal rupture at the basal posteroinferior wall with a large left-to-right shunt. Right ventricular free-wall intramyocardial dissection and tricuspid chordae rupture were noted. Coronary angiography demonstrated occlusion of the proximal right coronary artery, which was treated by balloon angioplasty and stenting. While preparing for surgical repair, the patient's overall cardiac and renal function deteriorated and surgery was contraindicated. The patient died 16 days after discharge. © 2014 Wiley Periodicals, Inc.

Early superoxide scavenging accelerates renal microvascular rarefaction and damage in the stenotic kidney.

PubMed

Kelsen, Silvia; He, Xiaochen; Chade, Alejandro R

2012-08-15

Renal artery stenosis (RAS), the main cause of chronic renovascular disease (RVD), is associated with significant oxidative stress. Chronic RVD induces renal injury partly by promoting renal microvascular (MV) damage and blunting MV repair in the stenotic kidney. We tested the hypothesis that superoxide anion plays a pivotal role in MV dysfunction, reduction of MV density, and progression of renal injury in the stenotic kidney. RAS was induced in 14 domestic pigs and observed for 6 wk. Seven RAS pigs were chronically treated with the superoxide dismutase mimetic tempol (RAS+T) to reduce oxidative stress. Single-kidney hemodynamics and function were quantified in vivo using multidetector computer tomography (CT) and renal MV density was quantified ex vivo using micro-CT. Expression of angiogenic, inflammatory, and apoptotic factors was measured in renal tissue, and renal apoptosis and fibrosis were quantified in tissue sections. The degree of RAS and blood pressure were similarly increased in RAS and RAS+T. Renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced in the stenotic kidney (280.1 ± 36.8 and 34.2 ± 3.1 ml/min, P < 0.05 vs. control). RAS+T kidneys showed preserved GFR (58.5 ± 6.3 ml/min, P = not significant vs. control) but a similar decreases in RBF (293.6 ± 85.2 ml/min) and further decreases in MV density compared with RAS. These changes were accompanied by blunted angiogenic signaling and increased apoptosis and fibrosis in the stenotic kidney of RAS+T compared with RAS. The current study shows that tempol administration provided limited protection to the stenotic kidney. Despite preserved GFR, renal perfusion was not improved by tempol, and MV density was further reduced compared with untreated RAS, associated with increased renal apoptosis and fibrosis. These results suggest that a tight balance of the renal redox status is necessary for a normal MV repair response to injury, at least at the early stage of RVD, and raise caution regarding antioxidant strategies in RAS.

Early superoxide scavenging accelerates renal microvascular rarefaction and damage in the stenotic kidney

PubMed Central

Kelsen, Silvia; He, Xiaochen

2012-01-01

Renal artery stenosis (RAS), the main cause of chronic renovascular disease (RVD), is associated with significant oxidative stress. Chronic RVD induces renal injury partly by promoting renal microvascular (MV) damage and blunting MV repair in the stenotic kidney. We tested the hypothesis that superoxide anion plays a pivotal role in MV dysfunction, reduction of MV density, and progression of renal injury in the stenotic kidney. RAS was induced in 14 domestic pigs and observed for 6 wk. Seven RAS pigs were chronically treated with the superoxide dismutase mimetic tempol (RAS+T) to reduce oxidative stress. Single-kidney hemodynamics and function were quantified in vivo using multidetector computer tomography (CT) and renal MV density was quantified ex vivo using micro-CT. Expression of angiogenic, inflammatory, and apoptotic factors was measured in renal tissue, and renal apoptosis and fibrosis were quantified in tissue sections. The degree of RAS and blood pressure were similarly increased in RAS and RAS+T. Renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced in the stenotic kidney (280.1 ± 36.8 and 34.2 ± 3.1 ml/min, P < 0.05 vs. control). RAS+T kidneys showed preserved GFR (58.5 ± 6.3 ml/min, P = not significant vs. control) but a similar decreases in RBF (293.6 ± 85.2 ml/min) and further decreases in MV density compared with RAS. These changes were accompanied by blunted angiogenic signaling and increased apoptosis and fibrosis in the stenotic kidney of RAS+T compared with RAS. The current study shows that tempol administration provided limited protection to the stenotic kidney. Despite preserved GFR, renal perfusion was not improved by tempol, and MV density was further reduced compared with untreated RAS, associated with increased renal apoptosis and fibrosis. These results suggest that a tight balance of the renal redox status is necessary for a normal MV repair response to injury, at least at the early stage of RVD, and raise caution regarding antioxidant strategies in RAS. PMID:22622460

Endothelin A receptor antagonists in congestive heart failure: blocking the beast while leaving the beauty untouched?

PubMed

Spieker, L E; Noll, G; Ruschitzka, F T; Lüscher, T F

2001-12-01

Congestive heart failure (CHF) is a disease process characterized by impaired left ventricular function, increased peripheral and pulmonary vascular resistance and reduced exercise tolerance and dyspnea. Thus, mediators involved in the control of myocardial function and vascular tone may be involved in its pathophysiology. The family of endothelins (ET) consists of four closely related peptides, ET-1, ET-2, ET-3, and ET-4, which cause vasoconstriction, cell proliferation, and myocardial effects through activation of ET(A) receptors. In contrast, endothelial ET(B) receptors mediate vasodilation via release of nitric oxide and prostacyclin. In addition, ET(B) receptors in the lung are a major pathway for the clearance of ET-1 from plasma. Thus, infusion of an ET(A) receptor antagonist into the brachial artery in healthy humans leads to vasodilation whereas infusion of an ET(B) receptor antagonist causes vasoconstriction. ET-1 plasma levels are elevated in CHF and correlate both with the hemodynamic severity and with symptoms. Plasma levels of ET-1 and its precursor, big ET-1, are strong independent predictors of death in patients after myocardial infarction and with CHF. ET-1 contributes to increased systemic and pulmonary vascular resistance, vascular dysfunction, myocardial ischemia, and renal impairment in CHF. Selective ET(A) as well as combined ET(A/B) receptor antagonists have been studied in patients with CHF showing impressive hemodynamic improvements (i.e. reduced peripheral vascular and pulmonary resistance as well as increased cardiac output). These results indicate that ET receptor antagonists indeed have a potential to improve hemodynamics, symptoms, and potentially prognosis of CHF which still carries a high mortality.

Renal uptake of radiolabeled octreotide in human subjects is efficiently inhibited by succinylated gelatin.

PubMed

Vegt, Erik; Wetzels, Jack F M; Russel, Frans G M; Masereeuw, Rosalinde; Boerman, Otto C; van Eerd, Juliette E; Corstens, Frans H M; Oyen, Wim J G

2006-03-01

Peptide receptor-mediated radiotherapy of neuroendocrine and other somatostatin receptor-positive tumors with radiolabeled somatostatin analogs has been applied in several experimental settings. The kidneys are the organs responsible for dose-limiting toxicity attributable to the retention of radiolabeled octreotide in the renal cortex, leading to a relatively high radiation dose that may result in irreversible loss of kidney function. The administration of basic amino acids reduces renal uptake but does have significant side effects. We observed that gelatin-based plasma expanders induced tubular low-molecular-weight proteinuria in healthy volunteers, suggesting that components in these solutions can interfere with the tubular reabsorption of proteins and peptides. Here, we studied the effects of infusion of low doses of the plasma expander succinylated gelatin (GELO) on the renal uptake of 111In-labeled octreotide (111In-OCT). Five healthy volunteers were given 111In-OCT, first in combination with normal saline and 2 wk later in combination with GELO. Scintigraphic images of the kidneys as well as blood and urine samples were analyzed. To exclude a nonspecific hemodynamic effect of the plasma expander, the procedure was repeated with 5 other volunteers who received the carbohydrate-based plasma expander hydroxyethyl starch (HES). Low doses of GELO were able to effectively reduce the kidney retention of 111In-OCT. The renal radiation dose was significantly reduced by 45% +/- 10% (mean +/- SD) (P = 0.006), whereas HES showed no significant effect (0% +/- 12%). The infusion of GELO did not cause any side effects. GELO effectively reduces the renal uptake of 111In-OCT. In contrast to currently used mixtures of amino acids, GELO does not cause any side effects.

Worsening Renal Function in Patients With Acute Heart Failure Undergoing Aggressive Diuresis Is Not Associated With Tubular Injury.

PubMed

Ahmad, Tariq; Jackson, Keyanna; Rao, Veena S; Tang, W H Wilson; Brisco-Bacik, Meredith A; Chen, Horng H; Felker, G Michael; Hernandez, Adrian F; O'Connor, Christopher M; Sabbisetti, Venkata S; Bonventre, Joseph V; Wilson, F Perry; Coca, Steven G; Testani, Jeffrey M

2018-05-08

Worsening renal function (WRF) in the setting of aggressive diuresis for acute heart failure treatment may reflect renal tubular injury or simply indicate a hemodynamic or functional change in glomerular filtration. Well-validated tubular injury biomarkers, N -acetyl-β-d-glucosaminidase, neutrophil gelatinase-associated lipocalin, and kidney injury molecule 1, are now available that can quantify the degree of renal tubular injury. The ROSE-AHF trial (Renal Optimization Strategies Evaluation-Acute Heart Failure) provides an experimental platform for the study of mechanisms of WRF during aggressive diuresis for acute heart failure because the ROSE-AHF protocol dictated high-dose loop diuretic therapy in all patients. We sought to determine whether tubular injury biomarkers are associated with WRF in the setting of aggressive diuresis and its association with prognosis. Patients in the multicenter ROSE-AHF trial with baseline and 72-hour urine tubular injury biomarkers were analyzed (n=283). WRF was defined as a ≥20% decrease in glomerular filtration rate estimated with cystatin C. Consistent with protocol-driven aggressive dosing of loop diuretics, participants received a median 560 mg IV furosemide equivalents (interquartile range, 300-815 mg), which induced a urine output of 8425 mL (interquartile range, 6341-10 528 mL) over the 72-hour intervention period. Levels of N -acetyl-β-d-glucosaminidase and kidney injury molecule 1 did not change with aggressive diuresis (both P >0.59), whereas levels of neutrophil gelatinase-associated lipocalin decreased slightly (-8.7 ng/mg; interquartile range, -169 to 35 ng/mg; P <0.001). WRF occurred in 21.2% of the population and was not associated with an increase in any marker of renal tubular injury: neutrophil gelatinase-associated lipocalin ( P =0.21), N -acetyl-β-d-glucosaminidase ( P =0.46), or kidney injury molecule 1 ( P =0.22). Increases in neutrophil gelatinase-associated lipocalin, N -acetyl-β-d-glucosaminidase, and kidney injury molecule 1 were paradoxically associated with improved survival (adjusted hazard ratio, 0.80 per 10 percentile increase; 95% confidence interval, 0.69-0.91; P =0.001). Kidney tubular injury does not appear to have an association with WRF in the context of aggressive diuresis of patients with acute heart failure. These findings reinforce the notion that the small to moderate deteriorations in renal function commonly encountered with aggressive diuresis are dissimilar from traditional causes of acute kidney injury. © 2018 American Heart Association, Inc.

Rhabdomyolysis and acute kidney injury in patients with traumatic spinal cord injury

PubMed Central

Galeiras, Rita; Mourelo, Mónica; Pértega, Sonia; Lista, Amanda; Ferreiro, Mª Elena; Salvador, Sebastián; Montoto, Antonio; Rodríguez, Antonio

2016-01-01

Background: Patients with acute traumatic spinal cord injuries (SCIs) exhibit factors that, in other populations, have been associated with rhabdomyolysis. Purpose: The aim of the study is to determine the incidence of rhabdomyolysis in patients with acute traumatic SCI admitted to the Intensive Care Unit (ICU), as well as the development of secondary acute kidney injury and associated factors. Study Design and Setting: This was an observational, retrospective study. Patient Sample: All adult patients admitted to the ICU with acute traumatic SCI who presented rhabdomyolysis, diagnosed through creatine phosphokinase (CPK) levels >500 IU/L. Outcome Measures: Incidence of rhabdomyolysis and subsequent renal dysfunction was calculated. Materials and Methods: Data about demographic variables, comorbidity, rhabdomyolysis risk factors, and variables involving SCI, severity scores, and laboratory parameters were obtained from clinical records. Multivariate logistic regression was used to identify renal injury risk factors. Results: In 2006–2014, 200 patients with acute SCI were admitted to ICU. Of these, 103 had rhabdomyolysis (incidence = 51.5%; 95% confidence interval [CI]: 44.3%–58.7%). The most typical American Spinal Injury Association classification was A (70.3%). The injury severity score was 30.3 ± 12.1 and sequential organ failure assessment (SOFA) score was 5.6 ± 3.3 points. During their stay, 57 patients (55.3%; 95% CI: 45.2%–65.4%) presented renal dysfunction (creatinine ≥1.2 mg/dL). In the multivariate analysis, variables associated with renal dysfunction were creatinine at admission (odds ratio [OR] = 9.20; P = 0.006) and hemodynamic SOFA score the day following admission (OR = 1.33; P = 0.024). Creatinine was a better predictor of renal dysfunction than the peak CPK value during the rhabdomyolysis (area under the receiver operating characteristic curve: 0.91 vs. 0.63, respectively). Conclusions: Rhabdomyolysis is a frequent condition in patients with acute traumatic SCI admitted to the ICU, and renal dysfunction occurs in half of the cases. Creatinine values should be requested starting at the admission while neither the peak CPK values nor the hemodynamic SOFA scores could be used to properly discriminate between patients with and without renal dysfunction. PMID:27688625

Renal denervation decreases blood pressure and renal tyrosine hydroxylase but does not augment the effect of hypotensive drugs.

PubMed

Skrzypecki, Janusz; Gawlak, Maciej; Huc, Tomasz; Szulczyk, Paweł; Ufnal, Marcin

2017-01-01

The effect of renal denervation on the efficacy of antihypertensive drugs has not yet been elucidated. Twenty-week-old spontaneously hypertensive rats were treated with metoprolol, losartan, indapamide, or saline (controls) and assigned to renal denervation or a sham procedure. Acute hemodynamic measurements were performed ten days later. Series showing a significant interaction between renal denervation and the drugs were repeated with chronic telemetry measurements. In the saline series, denervated rats showed a significantly lower mean arterial blood pressure (blood pressure) than the sham-operated rats. In contrast, in the metoprolol series denervated rats showed a significantly higher blood pressure than sham rats. There were no differences in blood pressure between denervated and sham rats in the losartan and indapamide series. In chronic studies, a 4-week treatment with metoprolol caused a decrease in blood pressure. Renal denervation and sham denervation performed 10 days after the onset of metoprolol treatment did not affect blood pressure. Denervated rats showed markedly reduced renal nerve tyrosine hydroxylase levels. In conclusion, renal denervation decreases blood pressure in hypertensive rats. The hypotensive action of metoprolol, indapamide, and losartan is not augmented by renal denervation, suggesting the absence of synergy between renal denervation and the drugs investigated in this study.

Mannitol increases renal blood flow and maintains filtration fraction and oxygenation in postoperative acute kidney injury: a prospective interventional study.

PubMed

Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2012-08-17

Acute kidney injury (AKI), which is a major complication after cardiovascular surgery, is associated with significant morbidity and mortality. Diuretic agents are frequently used to improve urine output and to facilitate fluid management in these patients. Mannitol, an osmotic diuretic, is used in the perioperative setting in the belief that it exerts reno-protective properties. In a recent study on uncomplicated postcardiac-surgery patients with normal renal function, mannitol increased glomerular filtration rate (GFR), possibly by a deswelling effect on tubular cells. Furthermore, experimental studies have previously shown that renal ischemia causes an endothelial cell injury and dysfunction followed by endothelial cell edema. We studied the effects of mannitol on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO2), and extraction (RO2Ex) in early, ischemic AKI after cardiac surgery. Eleven patients with AKI were studied during propofol sedation and mechanical ventilation 2 to 6 days after complicated cardiac surgery. All patients had severe heart failure treated with one (100%) or two (73%) inotropic agents and intraaortic balloon pump (36%). Systemic hemodynamics were measured with a pulmonary artery catheter. RBF and renal filtration fraction (FF) were measured by the renal vein thermo-dilution technique and by renal extraction of chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), respectively. GFR was calculated as the product of FF and renal plasma flow RBF × (1-hematocrit). RVO2 and RO2Ex were calculated from arterial and renal vein blood samples according to standard formulae. After control measurements, a bolus dose of mannitol, 225 mg/kg, was given, followed by an infusion at a rate of 75 mg/kg/h for two 30-minute periods. Mannitol did not affect cardiac index or cardiac filling pressures. Mannitol increased urine flow by 61% (P < 0.001). This was accompanied by a 12% increase in RBF (P < 0.05) and a 13% decrease in renal vascular resistance (P < 0.05). Mannitol increased the RBF/cardiac output (CO) relation (P = 0.040). Mannitol caused no significant changes in RO2Ext or renal FF. Mannitol treatment of postoperative AKI induces a renal vasodilation and redistributes systemic blood flow to the kidneys. Mannitol does not affect filtration fraction or renal oxygenation, suggestive of balanced increases in perfusion/filtration and oxygen demand/supply.

Mannitol increases renal blood flow and maintains filtration fraction and oxygenation in postoperative acute kidney injury: a prospective interventional study

PubMed Central

2012-01-01

Introduction Acute kidney injury (AKI), which is a major complication after cardiovascular surgery, is associated with significant morbidity and mortality. Diuretic agents are frequently used to improve urine output and to facilitate fluid management in these patients. Mannitol, an osmotic diuretic, is used in the perioperative setting in the belief that it exerts reno-protective properties. In a recent study on uncomplicated postcardiac-surgery patients with normal renal function, mannitol increased glomerular filtration rate (GFR), possibly by a deswelling effect on tubular cells. Furthermore, experimental studies have previously shown that renal ischemia causes an endothelial cell injury and dysfunction followed by endothelial cell edema. We studied the effects of mannitol on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO2), and extraction (RO2Ex) in early, ischemic AKI after cardiac surgery. Methods Eleven patients with AKI were studied during propofol sedation and mechanical ventilation 2 to 6 days after complicated cardiac surgery. All patients had severe heart failure treated with one (100%) or two (73%) inotropic agents and intraaortic balloon pump (36%). Systemic hemodynamics were measured with a pulmonary artery catheter. RBF and renal filtration fraction (FF) were measured by the renal vein thermo-dilution technique and by renal extraction of chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), respectively. GFR was calculated as the product of FF and renal plasma flow RBF × (1-hematocrit). RVO2 and RO2Ex were calculated from arterial and renal vein blood samples according to standard formulae. After control measurements, a bolus dose of mannitol, 225 mg/kg, was given, followed by an infusion at a rate of 75 mg/kg/h for two 30-minute periods. Results Mannitol did not affect cardiac index or cardiac filling pressures. Mannitol increased urine flow by 61% (P < 0.001). This was accompanied by a 12% increase in RBF (P < 0.05) and a 13% decrease in renal vascular resistance (P < 0.05). Mannitol increased the RBF/cardiac output (CO) relation (P = 0.040). Mannitol caused no significant changes in RO2Ext or renal FF. Conclusions Mannitol treatment of postoperative AKI induces a renal vasodilation and redistributes systemic blood flow to the kidneys. Mannitol does not affect filtration fraction or renal oxygenation, suggestive of balanced increases in perfusion/filtration and oxygen demand/supply. PMID:22901953

A Cough Deteriorating Gross Hematuria: A Clinical Sign of a Forthcoming Life-Threatening Rupture of an Intraparenchymal Aneurysm of Renal Artery (Wunderlich's Syndrome)

PubMed Central

Anastasiou, Ioannis; Pournaras, Christos; Mitropoulos, Dionysios; Constantinides, Constantinos A.

2013-01-01

Macroscopic hematuria regards the 4% to 20% of all urological visits. Renal artery aneurysms (RAAs) are detected in approximately 0.01%–1% of the general population, while intraparenchymal renal artery aneurysms (IPRAAs) are even more rarely detected in less than 10% of patients with RAAs. We present a case of a 58-year-old woman that came into the emergency room (ER) complaining of a gross hematuria during the last four days. Although in the ER room the first urine sample was clear after a cough episode, a severe gross hematuria began which led to a hemodynamically unstable patient. Finally, a radical nephrectomy was performed, and an IPRAA was the final diagnosis. A cough deteriorating hematuria could be attributed to a ruptured intraparenchymal renal artery aneurysm, which even though constitutes a rare entity, it is a life-threatening medical emergency. PMID:23864981

Milrinone is preferred to levosimendan for mesenteric perfusion in hypoxia-reoxygenated newborn piglets treated with dopamine

PubMed Central

Manouchehri, Namdar; Bigam, David L.; Churchill, Thomas; Joynt, Chloe; Vento, Maximo; Cheung, Po-Yin

2016-01-01

INTRODUCTION There is little information regarding the comparative hemodynamic effects of adding milrinone or levosimendan to dopamine infusion in hypoxia-reoxygenated (H-R) newborns. RESULTS Severely hypoxic piglets had cardiogenic shock with depressed cardiac index (CI) and mean arterial pressure (MAP). The hemodynamics deteriorated gradually after initial recovery upon reoxygenation. Heart rate and CI improved with milrinone (D+M) and levosimendan (D+L) administration (P < 0.05 vs. control). Both regimens improved carotid arterial flow and carotid vascular resistance; D+M additionally improved superior mesentric arterial flow (all P < 0.05 vs. control). No effect was found on renal arterial flow or elevated lactate state with either regimen. D+M piglets also had a lower myocardial oxidized/reduced glutathione ratio (P < 0.05 vs. control). DISCUSSION In conclusion, adding milrinone or levosimendan to dopamine similarly improved systemic hemodynamics in H-R newborn piglets. Milrinone also improved mesenteric perfusion and attenuated myocardial oxidative stress. METHODS Twenty-eight piglets (1–4 d, 1.5–2.5 kg) were instrumented for continuous monitoring of systemic MAP and pulmonary arterial pressure (PAP), CI, and carotid, superior mesenteric, and renal arterial flows. Piglets were randomized with blinding to sham-operated, H-R control (saline), and H-R dopamine (10 μg/kg/min) with D+M or D+L groups. H-R piglets underwent H-R followed by 2 h of drug infusion after reoxygenation. Tissue was collected for biochemical/oxidative stress testing and histological analysis. PMID:22337258

Milrinone is preferred to levosimendan for mesenteric perfusion in hypoxia-reoxygenated newborn piglets treated with dopamine.

PubMed

Manouchehri, Namdar; Bigam, David L; Churchill, Thomas; Joynt, Chloe; Vento, Maximo; Cheung, Po-Yin

2012-03-01

There is little information regarding the comparative hemodynamic effects of adding milrinone or levosimendan to dopamine infusion in hypoxia-reoxygenated (H-R) newborns. Severely hypoxic piglets had cardiogenic shock with depressed cardiac index (CI) and mean arterial pressure (MAP). The hemodynamics deteriorated gradually after initial recovery upon reoxygenation. Heart rate and CI improved with milrinone (D+M) and levosimendan (D+L) administration (P < 0.05 vs. control). Both regimens improved carotid arterial flow and carotid vascular resistance; D+M additionally improved superior mesentric arterial flow (all P < 0.05 vs. control). No effect was found on renal arterial flow or elevated lactate state with either regimen. D+M piglets also had a lower myocardial oxidized/reduced glutathione ratio (P < 0.05 vs. control). In conclusion, adding milrinone or levosimendan to dopamine similarly improved systemic hemodynamics in H-R newborn piglets. Milrinone also improved mesenteric perfusion and attenuated myocardial oxidative stress. Twenty-eight piglets (1-4 d, 1.5-2.5 kg) were instrumented for continuous monitoring of systemic MAP and pulmonary arterial pressure (PAP), CI, and carotid, superior mesenteric, and renal arterial flows. Piglets were randomized with blinding to sham-operated, H-R control (saline), and H-R dopamine (10 μg/kg/min) with D+M or D+L groups. H-R piglets underwent H-R followed by 2 h of drug infusion after reoxygenation. Tissue was collected for biochemical/oxidative stress testing and histological analysis.

Resting-state hemodynamics are spatiotemporally coupled to synchronized and symmetric neural activity in excitatory neurons.

PubMed

Ma, Ying; Shaik, Mohammed A; Kozberg, Mariel G; Kim, Sharon H; Portes, Jacob P; Timerman, Dmitriy; Hillman, Elizabeth M C

2016-12-27

Brain hemodynamics serve as a proxy for neural activity in a range of noninvasive neuroimaging techniques including functional magnetic resonance imaging (fMRI). In resting-state fMRI, hemodynamic fluctuations have been found to exhibit patterns of bilateral synchrony, with correlated regions inferred to have functional connectivity. However, the relationship between resting-state hemodynamics and underlying neural activity has not been well established, making the neural underpinnings of functional connectivity networks unclear. In this study, neural activity and hemodynamics were recorded simultaneously over the bilateral cortex of awake and anesthetized Thy1-GCaMP mice using wide-field optical mapping. Neural activity was visualized via selective expression of the calcium-sensitive fluorophore GCaMP in layer 2/3 and 5 excitatory neurons. Characteristic patterns of resting-state hemodynamics were accompanied by more rapidly changing bilateral patterns of resting-state neural activity. Spatiotemporal hemodynamics could be modeled by convolving this neural activity with hemodynamic response functions derived through both deconvolution and gamma-variate fitting. Simultaneous imaging and electrophysiology confirmed that Thy1-GCaMP signals are well-predicted by multiunit activity. Neurovascular coupling between resting-state neural activity and hemodynamics was robust and fast in awake animals, whereas coupling in urethane-anesthetized animals was slower, and in some cases included lower-frequency (<0.04 Hz) hemodynamic fluctuations that were not well-predicted by local Thy1-GCaMP recordings. These results support that resting-state hemodynamics in the awake and anesthetized brain are coupled to underlying patterns of excitatory neural activity. The patterns of bilaterally-symmetric spontaneous neural activity revealed by wide-field Thy1-GCaMP imaging may depict the neural foundation of functional connectivity networks detected in resting-state fMRI.

Resting-state hemodynamics are spatiotemporally coupled to synchronized and symmetric neural activity in excitatory neurons

PubMed Central

Ma, Ying; Shaik, Mohammed A.; Kozberg, Mariel G.; Portes, Jacob P.; Timerman, Dmitriy

2016-01-01

Brain hemodynamics serve as a proxy for neural activity in a range of noninvasive neuroimaging techniques including functional magnetic resonance imaging (fMRI). In resting-state fMRI, hemodynamic fluctuations have been found to exhibit patterns of bilateral synchrony, with correlated regions inferred to have functional connectivity. However, the relationship between resting-state hemodynamics and underlying neural activity has not been well established, making the neural underpinnings of functional connectivity networks unclear. In this study, neural activity and hemodynamics were recorded simultaneously over the bilateral cortex of awake and anesthetized Thy1-GCaMP mice using wide-field optical mapping. Neural activity was visualized via selective expression of the calcium-sensitive fluorophore GCaMP in layer 2/3 and 5 excitatory neurons. Characteristic patterns of resting-state hemodynamics were accompanied by more rapidly changing bilateral patterns of resting-state neural activity. Spatiotemporal hemodynamics could be modeled by convolving this neural activity with hemodynamic response functions derived through both deconvolution and gamma-variate fitting. Simultaneous imaging and electrophysiology confirmed that Thy1-GCaMP signals are well-predicted by multiunit activity. Neurovascular coupling between resting-state neural activity and hemodynamics was robust and fast in awake animals, whereas coupling in urethane-anesthetized animals was slower, and in some cases included lower-frequency (<0.04 Hz) hemodynamic fluctuations that were not well-predicted by local Thy1-GCaMP recordings. These results support that resting-state hemodynamics in the awake and anesthetized brain are coupled to underlying patterns of excitatory neural activity. The patterns of bilaterally-symmetric spontaneous neural activity revealed by wide-field Thy1-GCaMP imaging may depict the neural foundation of functional connectivity networks detected in resting-state fMRI. PMID:27974609

The significance of serum urea and renal function in patients with heart failure.

PubMed

Gotsman, Israel; Zwas, Donna; Planer, David; Admon, Dan; Lotan, Chaim; Keren, Andre

2010-07-01

Renal function and urea are frequently abnormal in patients with heart failure (HF) and are predictive of increased mortality. The relative importance of each parameter is less clear. We prospectively compared the predictive value of renal function and serum urea on clinical outcome in patients with HF. Patients hospitalized with definite clinical diagnosis of HF (n = 355) were followed for short-term (1 yr) and long-term (mean, 6.5 yr) survival and HF rehospitalization. Increasing tertiles of discharge estimated glomerular filtration rate (eGFR) were an independent predictor of increased long-term survival (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.47-0.91; p = 0.01) but not short-term survival. Admission and discharge serum urea and blood urea nitrogen (BUN)/creatinine ratio were predictors of reduced short- and long-term survival on multivariate Cox regression analysis. Increasing tertiles of discharge urea were a predictor of reduced 1-year survival (HR, 2.13; 95% CI, 1.21-3.73; p = 0.009) and long-term survival (HR, 1.93; 95% CI, 1.37-2.71; p < 0.0001). Multivariate analysis including discharge eGFR and serum urea demonstrated that only serum urea remained a significant predictor of long-term survival; however, eGFR and BUN/creatinine ratio were both independently predictive of survival. Urea was more discriminative than eGFR in predicting long-term survival by area under the receiver operating characteristic curve (0.803 vs. 0.787; p = 0.01). Increasing tertiles of discharge serum urea and BUN/creatinine were independent predictors of HF rehospitalization and combined death and HF rehospitalization. This study suggests that serum urea is a more powerful predictor of survival than eGFR in patients with HF. This may be due to urea's relation to key biological parameters including renal, hemodynamic, and neurohormonal parameters pertaining to the overall clinical status of the patient with chronic HF.

Renal hemodynamics: the influence of the renal artery ostium flow diverter

NASA Astrophysics Data System (ADS)

Rossmann, Jenn Stroud; Albert, Scott; Balaban, Robert

2013-11-01

The recently identified renal artery ostium flow diverter may preferentially direct blood flow to the renal arteries, and may also influence flow patterns and recirculation known to be involved in atherogenesis. Three-dimensional computational fluid dynamics (CFD) simulations of steady and pulsatile blood flow are performed to investigate the influence of diverter size and position, and vascular geometry, on the flow patterns and fluid mechanical forces in the neighborhood of the diverter. CFD results show that the flow diverter does affect the blood distribution: depending on the diverter's position, the flow to the renal arteries may be increased or reduced. The results of simulations also show the diverter's effect on the Wall Shear Stress (WSS) distribution, and suggest that the diverter contributes to an atherogenic environment in the abdominal aorta, while being atheroprotective in the renal arteries themselves. These results support previous clinical findings, and suggest directions for further clinical study. The results of this work have direct implications in understanding the physiological significance of the diverter, and its potential role in the pathophysiological development of atherosclerosis.

Arterial spin labeling MRI is able to detect early hemodynamic changes in diabetic nephropathy.

PubMed

Mora-Gutiérrez, José María; Garcia-Fernandez, Nuria; Slon Roblero, M Fernanda; Páramo, Jose A; Escalada, F Javier; Wang, Danny Jj; Benito, Alberto; Fernández-Seara, María A

2017-12-01

To investigate whether arterial spin labeling (ASL) MRI could detect renal hemodynamic impairment in diabetes mellitus (DM) along different stages of chronic kidney disease (CKD). Three Tesla (3T) ASL-MRI was performed to evaluate renal blood flow (RBF) in 91 subjects (46 healthy volunteers and 45 type 2 diabetic patients). Patients were classified according to their estimated glomerular filtration rate (eGFR) as group I (eGFR > 60 mL/min/1.73 m 2 ), group II (60 ≥ eGFR>30 mL/min/1.73 m 2 ), or group III (eGFR ≤ 30 mL/min/1.73 m 2 ), to determine differences depending on renal function. Studies were performed at 3T using a 12-channel flexible body array combined with the spine array coil as receiver. A 28% reduction in cortical RBF was seen in diabetics in comparison with healthy controls (185.79 [54.60] versus 258.83 [37.96] mL/min/100 g, P < 3 × 10 -6 ). Differences were also seen between controls and diabetic patients despite normal eGFR and absence of overt albuminuria (RBF [mL/min/100 g]: controls=258.83 [37.96], group I=208.89 [58.83], P = 0.0018; eGFR [mL/min/1.73 m 2 ]: controls = 95.50 [12.60], group I = 82.00 [20.76], P > 0.05; albumin-creatinine ratio [mg/g]: controls = 3.50 [4.45], group I = 17.50 [21.20], P > 0.05). A marked decrease in RBF was noted a long with progression of diabetic nephropathy (DN) through the five stages of CKD (χ 2  = 43.58; P = 1.85 × 10 -9 ). Strong correlation (r = 0.62; P = 4 × 10 -10 ) was obtained between RBF and GFR estimated by cystatin C. ASL-MRI is able to quantify early renal perfusion impairment in DM, as well as changes according to different CKD stages of DN. In addition, we demonstrated a correlation of RBF quantified by ASL and GFR estimated by cystatin C. 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1810-1817. © 2017 International Society for Magnetic Resonance in Medicine.

Correlation between electrical and hemodynamic responses during visual stimulation with graded contrasts

NASA Astrophysics Data System (ADS)

Si, Juanning; Zhang, Xin; Li, Yuejun; Zhang, Yujin; Zuo, Nianming; Jiang, Tianzi

2016-09-01

Brain functional activity involves complex cellular, metabolic, and vascular chain reactions, making it difficult to comprehend. Electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) have been combined into a multimodal neuroimaging method that captures both electrophysiological and hemodynamic information to explore the spatiotemporal characteristics of brain activity. Because of the significance of visually evoked functional activity in clinical applications, numerous studies have explored the amplitude of the visual evoked potential (VEP) to clarify its relationship with the hemodynamic response. However, relatively few studies have investigated the influence of latency, which has been frequently used to diagnose visual diseases, on the hemodynamic response. Moreover, because the latency and the amplitude of VEPs have different roles in coding visual information, investigating the relationship between latency and the hemodynamic response should be helpful. In this study, checkerboard reversal tasks with graded contrasts were used to evoke visual functional activity. Both EEG and fNIRS were employed to investigate the relationship between neuronal electrophysiological activities and the hemodynamic responses. The VEP amplitudes were linearly correlated with the hemodynamic response, but the VEP latency showed a negative linear correlation with the hemodynamic response.

Hemodynamic Instability during Dialysis: The Potential Role of Intradialytic Exercise

PubMed Central

Horton, Elizabeth Jane; Renshaw, Derek; Jimenez, Alofonso; Krishnan, Nithya

2018-01-01

Acute haemodynamic instability is a natural consequence of disordered cardiovascular physiology during haemodialysis (HD). Prevalence of intradialytic hypotension (IDH) can be as high as 20–30%, contributing to subclinical, transient myocardial ischemia. In the long term, this results in progressive, maladaptive cardiac remodeling and impairment of left ventricular function. This is thought to be a major contributor to increased cardiovascular mortality in end stage renal disease (ESRD). Medical strategies to acutely attenuate haemodynamic instability during HD are suboptimal. Whilst a programme of intradialytic exercise training appears to facilitate numerous chronic adaptations, little is known of the acute physiological response to this type of exercise. In particular, the potential for intradialytic exercise to acutely stabilise cardiovascular hemodynamics, thus preventing IDH and myocardial ischemia, has not been explored. This narrative review aims to summarise the characteristics and causes of acute haemodynamic instability during HD, with an overview of current medical therapies to treat IDH. Moreover, we discuss the acute physiological response to intradialytic exercise with a view to determining the potential for this nonmedical intervention to stabilise cardiovascular haemodynamics during HD, improve coronary perfusion, and reduce cardiovascular morbidity and mortality in ESRD. PMID:29682559

Detailing the relation between renal T2* and renal tissue pO2 using an integrated approach of parametric magnetic resonance imaging and invasive physiological measurements.

PubMed

Pohlmann, Andreas; Arakelyan, Karen; Hentschel, Jan; Cantow, Kathleen; Flemming, Bert; Ladwig, Mechthild; Waiczies, Sonia; Seeliger, Erdmann; Niendorf, Thoralf

2014-08-01

This study was designed to detail the relation between renal T2* and renal tissue pO2 using an integrated approach that combines parametric magnetic resonance imaging (MRI) and quantitative physiological measurements (MR-PHYSIOL). Experiments were performed in 21 male Wistar rats. In vivo modulation of renal hemodynamics and oxygenation was achieved by brief periods of aortic occlusion, hypoxia, and hyperoxia. Renal perfusion pressure (RPP), renal blood flow (RBF), local cortical and medullary tissue pO2, and blood flux were simultaneously recorded together with T2*, T2 mapping, and magnetic resonance-based kidney size measurements (MR-PHYSIOL). Magnetic resonance imaging was carried out on a 9.4-T small-animal magnetic resonance system. Relative changes in the invasive quantitative parameters were correlated with relative changes in the parameters derived from MRI using Spearman analysis and Pearson analysis. Changes in T2* qualitatively reflected tissue pO2 changes induced by the interventions. T2* versus pO2 Spearman rank correlations were significant for all interventions, yet quantitative translation of T2*/pO2 correlations obtained for one intervention to another intervention proved not appropriate. The closest T2*/pO2 correlation was found for hypoxia and recovery. The interlayer comparison revealed closest T2*/pO2 correlations for the outer medulla and showed that extrapolation of results obtained for one renal layer to other renal layers must be made with due caution. For T2* to RBF relation, significant Spearman correlations were deduced for all renal layers and for all interventions. T2*/RBF correlations for the cortex and outer medulla were even superior to those between T2* and tissue pO2. The closest T2*/RBF correlation occurred during hypoxia and recovery. Close correlations were observed between T2* and kidney size during hypoxia and recovery and for occlusion and recovery. In both cases, kidney size correlated well with renal vascular conductance, as did renal vascular conductance with T2*. Our findings indicate that changes in T2* qualitatively mirror changes in renal tissue pO2 but are also associated with confounding factors including vascular volume fraction and tubular volume fraction. Our results demonstrate that MR-PHYSIOL is instrumental to detail the link between renal tissue pO2 and T2* in vivo. Unravelling the link between regional renal T2* and tissue pO2, including the role of the T2* confounding parameters vascular and tubular volume fraction and oxy-hemoglobin dissociation curve, requires further research. These explorations are essential before the quantitative capabilities of parametric MRI can be translated from experimental research to improved clinical understanding of hemodynamics/oxygenation in kidney disorders.

[News in peritoneal dialysis].

PubMed

Ryckelynck, Jean-Philippe; Lobbedez, Thierry; Ficheux, Maxence; Bonnamy, Cécile; El Haggan, Waël; Henri, Patrick; Chatelet, Valérie; Levaltier, Béatrice; Hurault de Ligny, Bruno

2007-12-01

Peritoneal dialysis, like hemodialysis, is a first-line therapy for patients with end-stage renal disease. Progress in medical devices and materials has reduced infectious complications such as peritonitis and catheter exit-site infections and thus decreased morbidity. Peritoneal dialysis fluids are increasingly biocompatible, result in fewer glucose degradation products, protect the peritoneal membrane better and thus improve tolerance. The maintenance of residual renal function, together with better comfort and no pain, help control the fluid and sodium balance. Automated peritoneal dialysis can be performed each night, either autonomously or assisted by a visiting nurse twice a day (to prepare, connect, and disconnect the machine). This treatment can thus be provided to most patients, regardless of their age. Peritoneal dialysis is indicated principally for young people waiting for a kidney transplantation (to preserve their vascular network), elderly patients who wish to remain either at home or in an institution, and patients with cardiac insufficiency, because of the better hemodynamic tolerance. Numerous obstacles, mainly nonmedical, still impede the development of peritoneal dialysis. Patients seen in emergencies start hemodialysis without necessarily receiving any information about peritoneal dialysis. Indeed, neither physicians nor patients receive adequate information.

[Evaluation of upper urinary tract function in patients undergoing autoplastic surgery for hydronphrosis of the intrarenal pelvis].

PubMed

Kurbanaliev, R M; Usupbaev, A Ch; Kolesnichenko, I V; Sadyrbekov, N Zh; Sultanov, B M

2018-05-01

To investigate the functional state of the upper urinary tract in patients undergoing autoplastic surgery for a hydronophrosis of the intrarenal pelvis. The study comprised 78 patients with the intrarenal pelvis and impaired urinary outflow due to stricture of the ureteropelvic junction and vascular conflict (interatrial and arteriovenous narrowing), who underwent pyeloplasty using autologous tunica vaginalis. All patients underwent an incision of ureteropelvic stricture and resection of the parietal layer of the tunica vaginalis which was used to repair the obstruction site and internal stenting of the upper urinary tract. The patients were examined at baseline and during follow-up ranging from 3 months to 3 years. At three months after surgery, there was a decrease in the size of the renal pelvis and calyces with an improvement of all parameters of uro- and hemodynamics. At three years after surgery, the structural and functional parameters of the upper urinary tract were completely restored. Obstructive uropathy, resulting from the intrarenal pelvis, leads to persistently impaired urinary outflow from the upper urinary tract. Surgical intervention is the only curative treatment able to restore the urinary flow. In men with the intrarenal pelvis, the autoplastic surgery of the ureteropelvic junction obstruction using a parietal layer of the tunica vaginalis is an effective surgical modality improving renal pelvis capacity and contributing to the recovery of urinary outflow from the upper urinary tract.

State-of the-art review on the renal and visceral protection during open thoracoabdominal aortic aneurysm repair.

PubMed

Waked, Karl; Schepens, Marc

2018-01-01

During open thoracoabdominal aortic aneurysm repair (OTAAAR), there is an inevitable organ ischemic period that occurs when the abdominal arteries are being reattached to the aortic graft. Despite various protective techniques, the incidence of renal and visceral complications remains substantial. This state-of-the-art review gives an overview of the current and most evidence-based organ protection methods during OTAAAR, based on the most recent publications and personal experience. An electronic search was performed in four medical databases, using the following MeSH terms: thoracoabdominal aneurysm, TAAAR, visceral protection, renal protection, kidney, perfusion, and intestines. Every publication type was considered. The literature search was ended on August 31st, 2017. The left heart bypass (LHB) is currently the most frequent adjunct to provide distal aortic perfusion (DAP) during aortic clamping. Together with systemic hypothermia, it forms the cornerstone in organ protection during aortic clamping. Further renal protection can be obtained by selective renal perfusion (SRP) with cold blood or cold crystalloid solution, the latter enriched with mannitol. The perfusion should be administered in a volume- and pressure-controlled way and, if possible, by use of a pulsatile pump. Selective visceral perfusion (SVP) is not routinely used, as it does not provide adequate blood flow for visceral protection. The best way to protect the intestines is by minimizing the ischemic time. The preservation of renal and visceral function after OTAAAR can only be obtained with specific strategies before, during, and after the operation. This involves a series of measures, including selective digestive decontamination (SDD), avoidance of nephrotoxic drugs, minimizing the renal and intestinal ischemic time, systemic cooling, avoidance of hemodynamic instability, and regional protective perfusion of the kidneys. Future innovations in catheters, cardiac bypass flow types, mechanical components, hybrid vascular grafts, and pharmaceutical protection measures will hopefully further reduce organ complications.

Neural and Hemodynamic Responses Elicited by Forelimb- and Photo-stimulation in Channelrhodopsin-2 Mice: Insights into the Hemodynamic Point Spread Function

PubMed Central

Vazquez, Alberto L.; Fukuda, Mitsuhiro; Crowley, Justin C.; Kim, Seong-Gi

2014-01-01

Hemodynamic responses are commonly used to map brain activity; however, their spatial limits have remained unclear because of the lack of a well-defined and malleable spatial stimulus. To examine the properties of neural activity and hemodynamic responses, multiunit activity, local field potential, cerebral blood volume (CBV)-sensitive optical imaging, and laser Doppler flowmetry were measured from the somatosensory cortex of transgenic mice expressing Channelrhodopsin-2 in cortex Layer 5 pyramidal neurons. The magnitude and extent of neural and hemodynamic responses were modulated using different photo-stimulation parameters and compared with those induced by somatosensory stimulation. Photo-stimulation-evoked spiking activity across cortical layers was similar to forelimb stimulation, although their activity originated in different layers. Hemodynamic responses induced by forelimb- and photo-stimulation were similar in magnitude and shape, although the former were slightly larger in amplitude and wider in extent. Altogether, the neurovascular relationship differed between these 2 stimulation pathways, but photo-stimulation-evoked changes in neural and hemodynamic activities were linearly correlated. Hemodynamic point spread functions were estimated from the photo-stimulation data and its full-width at half-maximum ranged between 103 and 175 µm. Therefore, submillimeter functional structures separated by a few hundred micrometers may be resolved using hemodynamic methods, such as optical imaging and functional magnetic resonance imaging. PMID:23761666

Regression of albuminuria and hypertension and arrest of severe renal injury by a losartan-hydrochlorothiazide association in a model of very advanced nephropathy.

PubMed

Arias, Simone Costa Alarcon; Valente, Carla Perez; Machado, Flavia Gomes; Fanelli, Camilla; Origassa, Clarice Silvia Taemi; de Brito, Thales; Camara, Niels Olsen Saraiva; Malheiros, Denise Maria Avancini Costa; Zatz, Roberto; Fujihara, Clarice Kazue

2013-01-01

Treatments that effectively prevent chronic kidney disease (CKD) when initiated early often yield disappointing results when started at more advanced phases. We examined the long-term evolution of renal injury in the 5/6 nephrectomy model (Nx) and the effect of an association between an AT-1 receptor blocker, losartan (L), and hydrochlorothiazide (H), shown previously to be effective when started one month after Nx. Adult male Munich-Wistar rats underwent Nx, being divided into four groups: Nx+V, no treatment; Nx+L, receiving L monotherapy; Nx+LH, receiving the L+H association (LH), and Nx+AHHz, treated with the calcium channel blocker, amlodipine, the vascular relaxant, hydralazine, and H. This latter group served to assess the effect of lowering blood pressure (BP). Rats undergoing sham nephrectomy (S) were also studied. In a first protocol, treatments were initiated 60 days after Nx, when CKD is at a relatively early stage. In a second protocol, treatments were started 120 days after Nx, when glomerulosclerosis and interstitial fibrosis are already advanced. In both protocols, L treatment promoted only partial renoprotection, whereas LH brought BP, albuminuria, tubulointerstitial cell proliferation and plasma aldosterone below pretreatment levels, and completely detained progression of renal injury. Despite normalizing BP, the AHHz association failed to prevent renal damage, indicating that the renoprotective effect of LH was not due to a systemic hemodynamic action. These findings are inconsistent with the contention that thiazides are innocuous in advanced CKD. In Nx, LH promotes effective renoprotection even at advanced stages by mechanisms that may involve anti-inflammatory and intrarenal hemodynamic effects, but seem not to require BP normalization.

Using functional hemodynamic indicators to guide fluid therapy.

PubMed

Bridges, Elizabeth

2013-05-01

Hemodynamic monitoring has traditionally relied on such static pressure measurements as pulmonary artery occlusion pressure and central venous pressure to guide fluid therapy. Over the past 15 years, however, there's been a shift toward less invasive or noninvasive monitoring methods, which use "functional" hemodynamic indicators that reflect ventilator-induced changes in preload and thereby more accurately predict fluid responsiveness. The author reviews the physiologic principles underlying functional hemodynamic indicators, describes how the indicators are calculated, and discusses when and how to use them to guide fluid resuscitation in critically ill patients.

Renin-angiotensin-aldosterone system activation in long-standing type 1 diabetes

PubMed Central

Lovshin, Julie A.; Boulet, Geneviève; Lytvyn, Yuliya; Lovblom, Leif E.; Bjornstad, Petter; Lai, Vesta; Cham, Leslie; Tse, Josephine; Orszag, Andrej; Scarr, Daniel; Weisman, Alanna; Keenan, Hillary A.; Brent, Michael H.; Paul, Narinder; Perkins, Bruce A.; Cherney, David Z.I.

2018-01-01

BACKGROUND. In type 1 diabetes (T1D), adjuvant treatment with inhibitors of the renin-angiotensin-aldosterone system (RAAS), which dilate the efferent arteriole, is associated with prevention of progressive albuminuria and renal dysfunction. Uncertainty still exists as to why some individuals with long-standing T1D develop diabetic kidney disease (DKD) while others do not (DKD resistors). We hypothesized that those with DKD would be distinguished from DKD resistors by the presence of RAAS activation. METHODS. Renal and systemic hemodynamic function was measured before and after exogenous RAAS stimulation by intravenous infusion of angiotensin II (ANGII) in 75 patients with prolonged T1D durations and in equal numbers of nondiabetic controls. The primary outcome was change in renal vascular resistance (RVR) in response to RAAS stimulation, a measure of endogenous RAAS activation. RESULTS. Those with DKD had less change in RVR following exogenous RAAS stimulation compared with DKD resistors or controls (19%, 29%, 31%, P = 0.008, DKD vs. DKD resistors), reflecting exaggerated endogenous renal RAAS activation. All T1D participants had similar changes in renal efferent arteroilar resistance (9% vs. 13%, P = 0.37) irrespective of DKD status, which reflected less change versus controls (20%, P = 0.03). In contrast, those with DKD exhibited comparatively less change in afferent arteriolar vascular resistance compared with DKD resistors or controls (33%, 48%, 48%, P = 0.031, DKD vs. DKD resistors), indicating higher endogenous RAAS activity. CONCLUSION. In long-standing T1D, the intrarenal RAAS is exaggerated in DKD, which unexpectedly predominates at the afferent rather than the efferent arteriole, stimulating vasoconstriction. FUNDING. JDRF operating grant 17-2013-312. PMID:29321380

Abdominal Aortic Calcifications Influences the Systemic and Renal Hemodynamic Response to Renal Denervation in the DENERHTN (Renal Denervation for Hypertension) Trial.

PubMed

Courand, Pierre-Yves; Pereira, Helena; Del Giudice, Costantino; Gosse, Philippe; Monge, Matthieu; Bobrie, Guillaume; Delsart, Pascal; Mounier-Vehier, Claire; Lantelme, Pierre; Denolle, Thierry; Dourmap, Caroline; Halimi, Jean Michel; Girerd, Xavier; Rossignol, Patrick; Zannad, Faiez; Ormezzano, Olivier; Vaisse, Bernard; Herpin, Daniel; Ribstein, Jean; Bouhanick, Beatrice; Mourad, Jean-Jacques; Ferrari, Emile; Chatellier, Gilles; Sapoval, Marc; Azarine, Arshid; Azizi, Michel

2017-10-10

The DENERHTN (Renal Denervation for Hypertension) trial confirmed the efficacy of renal denervation (RDN) in lowering daytime ambulatory systolic blood pressure when added to standardized stepped-care antihypertensive treatment (SSAHT) for resistant hypertension at 6 months. This post hoc exploratory analysis assessed the impact of abdominal aortic calcifications (AAC) on the hemodynamic and renal response to RDN at 6 months. In total, 106 patients with resistant hypertension were randomly assigned to RDN plus SSAHT or to the same SSAHT alone (control group). Total AAC volume was measured, with semiautomatic software and blind to randomization, from the aortic hiatus to the iliac bifurcation using the prerandomization noncontrast abdominal computed tomography scans of 90 patients. Measurements were expressed as tertiles. The baseline-adjusted difference in the change in daytime ambulatory systolic blood pressure from baseline to 6 months between the RDN and control groups was -10.1 mm Hg ( P =0.0462) in the lowest tertile and -2.5 mm Hg ( P =0.4987) in the 2 highest tertiles of AAC volume. Estimated glomerular filtration rate remained stable at 6 months for the patients in the lowest tertile of AAC volume who underwent RDN (+2.5 mL/min per 1.73 m 2 ) but decreased in the control group (-8.0 mL/min per 1.73 m 2 , P =0.0148). In the 2 highest tertiles of AAC volume, estimated glomerular filtration rate decreased similarly in the RDN and control groups ( P =0.2640). RDN plus SSAHT resulted in a larger decrease in daytime ambulatory systolic blood pressure than SSAHT alone in patients with a lower AAC burden than in those with a higher AAC burden. This larger decrease in daytime ambulatory systolic blood pressure was not associated with a decrease in estimated glomerular filtration rate. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01570777. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Rifaximin has no effect on hemodynamics in decompensated cirrhosis: A randomized, double-blind, placebo-controlled trial.

PubMed

Kimer, Nina; Pedersen, Julie Steen; Busk, Troels Malte; Gluud, Lise Lotte; Hobolth, Lise; Krag, Aleksander; Møller, Søren; Bendtsen, Flemming

2017-02-01

Decompensated cirrhosis is characterized by disturbed systemic and splanchnic hemodynamics. Bacterial translocation from the gut is considered the key driver in this process. Intestinal decontamination with rifaximin may improve hemodynamics. This double-blind, randomized, controlled trial (clinicaltrials.gov, NCT01769040) investigates the effects of rifaximin on hemodynamics, renal function, and vasoactive hormones. We randomized 54 stable outpatients with cirrhosis and ascites to rifaximin 550 mg twice a day (n = 36) or placebo twice a day (n = 18). Forty-five patients were male, mean age 56 years (±8.4), average Child score 8.3 (±1.3), and Model for End-Stage Liver Disease score 11.7 (±3.9). Measurements of hepatic venous pressure gradient, cardiac output, and systemic vascular resistance were made at baseline and after 4 weeks. The glomerular filtration rate and plasma renin, noradrenaline, lipopolysaccharide binding protein, troponin T, and brain natriuretic peptide levels were measured. Rifaximin had no effect on hepatic venous pressure gradient, mean 16.8 ± 3.8 mm Hg at baseline versus 16.6 ± 5.3 mm Hg at follow-up, compared to the placebo, mean 16.4 ± 4 mm Hg at baseline versus 16.3 ± 4.4 mm Hg at follow-up, P = 0.94. No effect was found on cardiac output, mean 6.9 ± 1.7 L/min at baseline versus 6.9 ± 2.3 L/min at follow-up, compared to placebo, mean 6.6 ± 1.9 L/min at baseline compared to 6.5 ±2.1 L/min at follow-up, P = 0.66. No effects on the glomerular filtration rate, P = 0.14, or vasoactive hormones were found. Subgroup analyses on patients with increased lipopolysaccharide binding protein and systemic vascular resistance below the mean (1,011 dynes × s/cm 5 ) revealed no effect of rifaximin. Four weeks of treatment with rifaximin did not reduce the hepatic venous pressure gradient or improve systemic hemodynamics in patients with cirrhosis and ascites; rifaximin did not affect glomerular filtration rate or levels of vasoactive hormones. (Hepatology 2017;65:592-603). © 2016 by the American Association for the Study of Liver Diseases.

Renoprotective effect of the antioxidant curcumin: Recent findings☆

PubMed Central

Trujillo, Joyce; Chirino, Yolanda Irasema; Molina-Jijón, Eduardo; Andérica-Romero, Ana Cristina; Tapia, Edilia; Pedraza-Chaverrí, José

2013-01-01

For years, there have been studies based on the use of natural compounds plant-derived as potential therapeutic agents for various diseases in humans. Curcumin is a phenolic compound extracted from Curcuma longa rhizome commonly used in Asia as a spice, pigment and additive. In traditional medicine of India and China, curcumin is considered as a therapeutic agent used in several foods. Numerous studies have shown that curcumin has broad biological functions particularly antioxidant and antiinflammatory. In fact, it has been established that curcumin is a bifunctional antioxidant; it exerts antioxidant activity in a direct and an indirect way by scavenging reactive oxygen species and inducing an antioxidant response, respectively. The renoprotective effect of curcumin has been evaluated in several experimental models including diabetic nephropathy, chronic renal failure, ischemia and reperfusion and nephrotoxicity induced by compounds such as gentamicin, adriamycin, chloroquine, iron nitrilotriacetate, sodium fluoride, hexavalent chromium and cisplatin. It has been shown recently in a model of chronic renal failure that curcumin exerts a therapeutic effect; in fact it reverts not only systemic alterations but also glomerular hemodynamic changes. Another recent finding shows that the renoprotective effect of curcumin is associated to preservation of function and redox balance of mitochondria. Taking together, these studies attribute the protective effect of curcumin in the kidney to the induction of the master regulator of antioxidant response nuclear factor erythroid-derived 2 (Nrf2), inhibition of mitochondrial dysfunction, attenuation of inflammatory response, preservation of antioxidant enzymes and prevention of oxidative stress. The information presented in this paper identifies curcumin as a promising renoprotective molecule against renal injury. PMID:24191240

Neurovascular coupling in normal aging: a combined optical, ERP and fMRI study.

PubMed

Fabiani, Monica; Gordon, Brian A; Maclin, Edward L; Pearson, Melanie A; Brumback-Peltz, Carrie R; Low, Kathy A; McAuley, Edward; Sutton, Bradley P; Kramer, Arthur F; Gratton, Gabriele

2014-01-15

Brain aging is characterized by changes in both hemodynamic and neuronal responses, which may be influenced by the cardiorespiratory fitness of the individual. To investigate the relationship between neuronal and hemodynamic changes, we studied the brain activity elicited by visual stimulation (checkerboard reversals at different frequencies) in younger adults and in older adults varying in physical fitness. Four functional brain measures were used to compare neuronal and hemodynamic responses obtained from BA17: two reflecting neuronal activity (the event-related optical signal, EROS, and the C1 response of the ERP), and two reflecting functional hemodynamic changes (functional magnetic resonance imaging, fMRI, and near-infrared spectroscopy, NIRS). The results indicated that both younger and older adults exhibited a quadratic relationship between neuronal and hemodynamic effects, with reduced increases of the hemodynamic response at high levels of neuronal activity. Although older adults showed reduced activation, similar neurovascular coupling functions were observed in the two age groups when fMRI and deoxy-hemoglobin measures were used. However, the coupling between oxy- and deoxy-hemoglobin changes decreased with age and increased with increasing fitness. These data indicate that departures from linearity in neurovascular coupling may be present when using hemodynamic measures to study neuronal function. Copyright © 2013 Elsevier Inc. All rights reserved.

Age and Vascular Burden Determinants of Cortical Hemodynamics Underlying Verbal Fluency.

PubMed

Heinzel, Sebastian; Metzger, Florian G; Ehlis, Ann-Christine; Korell, Robert; Alboji, Ahmed; Haeussinger, Florian B; Wurster, Isabel; Brockmann, Kathrin; Suenkel, Ulrike; Eschweiler, Gerhard W; Maetzler, Walter; Berg, Daniela; Fallgatter, Andreas J

2015-01-01

Aging processes and several vascular burden factors have been shown to increase the risk of dementia including Alzheimer's disease. While pathological alterations in dementia precede diagnosis by many years, reorganization of brain processing might temporarily delay cognitive decline. We hypothesized that in healthy elderly individuals both age-related neural and vascular factors known to be related to the development of dementia impact functional cortical hemodynamics during increased cognitive demands. Vascular burden factors and cortical functional hemodynamics during verbal fluency were assessed in 1052 non-demented elderly individuals (51 to 83 years; cross-sectional data of the longitudinal TREND study) using functional near-infrared spectroscopy (fNIRS). The prediction of functional hemodynamic responses by age in multiple regressions and the impact of single and cumulative vascular burden factors including hypertension, diabetes, obesity, smoking and atherosclerosis were investigated. Replicating and extending previous findings we could show that increasing age predicted functional hemodynamics to be increased in right prefrontal and bilateral parietal cortex, and decreased in bilateral inferior frontal junction during phonological fluency. Cumulative vascular burden factors, with hypertension in particular, decreased left inferior frontal junction hemodynamic responses during phonological fluency. However, age and vascular burden factors showed no statistical interaction on functional hemodynamics. Based on these findings, one might hypothesize that increased fronto-parietal processing may represent age-related compensatory reorganization during increased cognitive demands. Vascular burden factors, such as hypertension, may contribute to regional cerebral hypoperfusion. These neural and vascular hemodynamic determinants should be investigated longitudinally and combined with other markers to advance the prediction of future cognitive decline and dementia.

Splenic injury during percutaneous nephrolithotomy.

PubMed

Thomas, Anil A; Pierce, Gregory; Walsh, R Matthew; Sands, Mark; Noble, Mark

2009-01-01

Injury to the spleen is a recognized complication during percutaneous renal access due to the close anatomical relationship of the spleen and the left kidney. However, transsplenic renal access is a rare complication of percutaneous nephrolithotomy and can also result in considerable morbidity, often requiring emergent splenectomy. We present our experience with splenic injury during percutaneous nephrolithotomy managed conservatively with the use of a collagen-thrombin hemostatic sealant (D-Stat; Vascular Solutions, Inc., Minneapolis, MN) after delayed removal of the nephrostomy tubes. The patient had an uneventful recovery and was discharged home on postoperative day 6. In select hemodynamically stable patients, nonoperative management with the adjunctive use of hemostatic sealants may be considered.

CytoSorb, a novel therapeutic approach for patients with septic shock: a case report.

PubMed

Hinz, Burkhard; Jauch, Oliver; Noky, Toralf; Friesecke, Sigrun; Abel, Peter; Kaiser, Rolf

2015-08-01

Hemoadsorption using CytoSorb has gained attention as a potential immunotherapy to control systemic inflammation and sepsis. We report on a patient with septic shock, successfully treated with CytoSorb therapy. A 72-year-old male with periodically recurring infectious episodes was admitted with the suspicion of urosepsis. In the following hours his hemodynamic situation deteriorated markedly, exhibiting respiratory-metabolic acidosis, elevated inflammatory marker plasma levels, a severely disturbed coagulation, increased retention parameters, liver dysfunction, and confirmation of bacteria and leucocytes in urine. After admission to the ICU in a state of septic shock the patient received renal support with additional hemoadsorption using CytoSorb. Three CytoSorb sessions were run during the following days. The first and consecutive second session resulted in a reduction of procalcitonin, C-reactive protein and bilirubin and a markedly reduced need for vasopressors while hemodynamics improved significantly (i.e., cardiac index, extravascular lung water). Due to a recurring inflammatory "second hit" episode, another session with CytoSorb was run, resulting in a marked decrease in leukocytosis and liver (dys)function parameters. The rapid hemodynamic stabilization with reduction of vasopressor needs within hours and reduction of the capillary leakage as well as a quick reduction in infection markers were the main conclusions drawn from the use of CytoSorb in this patient. Additionally, treatment appeared to be safe and was well tolerated. Despite the promising results of CytoSorb application in this patient, further studies are necessary to elucidate to what extent these favorable consequences are attributable to the adsorber itself.

Changes in Conjunctival Hemodynamics Predict Albuminuria in Sickle Cell Nephropathy

PubMed Central

Valeshabad, Ali Kord; Wanek, Justin; Saraf, Santosh L.; Gaynes, Bruce I.; Gordeuk, Victor R.; Molokie, Robert E.; Shahidi, Mahnaz

2015-01-01

Background Albuminuria is an early manifestation of deterioration in renal function in subjects with sickle cell disease (SCD). Hyperfiltration may be an early mechanism for kidney damage in SCD. The purpose of the current study was to determine the association between conjunctival hemodynamics and albuminuria in SCD subjects with preserved glomerular filtration rate. Methods Conjunctival microcirculation imaging was performed to measure conjunctival diameter (D) and axial blood velocity (V) in 35 SCD and 10 healthy control subjects. Albuminuria, defined as albumin excretion ratio (AER) was obtained from the medical charts. Based on the 95% confidence interval of conjunctival V in control subjects (0.40 - 0.60 mm/s), SCD subjects were allocated to three groups: V1 < 0.40 mm/s (N = 7), V2 of 0.40 – 0.60 mm/s (N = 18), and V3 ≥ 0.60 mm/s (N = 10). Results Mean log(AER) measurements in the V1, V2, and V3 groups were 1.08 ± 0.67 mg/g creatinine, 1.39 ± 0.59 mg/g creatinine, and 2.00 ± 0.91 mg/g creatinine, respectively, and followed a positive linear trend from the V1 to V3 groups (p = 0.01). By multivariate linear regression analysis, conjunctival V significantly correlated with albuminuria (p = 0.01) independent of age, blood pressure, α-thalassemia, hematocrit, white blood cell count, and lactate dehydrogenase concentration. Conclusions Increased conjunctival velocity is associated with albuminuria in sickle cell subjects. Assessment of conjunctival microvascular hemodynamics may improve our understanding of the pathophysiology and clinical course of sickle cell nephropathy. PMID:26278102

Hemodynamic and Anatomic Predictors of Renovisceral Stent-Graft Occlusion Following Chimney Endovascular Repair of Juxtarenal Aortic Aneurysms.

PubMed

Tricarico, Rosamaria; He, Yong; Laquian, Liza; Scali, Salvatore T; Tran-Son-Tay, Roger; Beck, Adam W; Berceli, Scott A

2017-12-01

To identify anatomic and hemodynamic changes associated with impending visceral chimney stent-graft occlusion after endovascular aneurysm repair (EVAR) with the chimney technique (chEVAR). A retrospective evaluation was performed of computed tomography scans from 41 patients who underwent juxtarenal chEVAR from 2008 to 2012 to identify stent-grafts demonstrating conformational changes following initial placement. Six subjects (mean age 74 years; 3 men) were selected for detailed reconstruction and computational hemodynamic analysis; 4 had at least 1 occluded chimney stent-graft. This subset of repairs was systematically analyzed to define the anatomic and hemodynamic impact of these changes and identify signature patterns associated with impending renovisceral stent-graft occlusion. Spatial and temporal analyses of cross-sectional area, centerline angle, intraluminal pressure, and wall shear stress (WSS) were performed within the superior mesenteric and renal artery chimney grafts used for repair. Conformational changes in the chimney stent-grafts and associated perturbations, in both local WSS and pressure, were responsible for the 5 occlusions in the 13 stented branches. Anatomic and hemodynamic signatures leading to occlusion were identified within 1 month postoperatively, with a lumen area <14 mm 2 (p=0.04), systolic pressure gradient >25 Pa/mm (p=0.03), and systolic WSS >45 Pa (p=0.03) associated with future chimney stent-graft occlusion. Chimney stent-grafts at increased risk for occlusion demonstrated anatomic and hemodynamic signatures within 1 month of juxtarenal chEVAR. Analysis of these parameters in the early postoperative period may be useful for identifying and remediating these high-risk stent-grafts.

[Metabolic acidosis].

PubMed

Regolisti, Giuseppe; Fani, Filippo; Antoniotti, Riccardo; Castellano, Giuseppe; Cremaschi, Elena; Greco, Paolo; Parenti, Elisabetta; Morabito, Santo; Sabatino, Alice; Fiaccadori, Enrico

2016-01-01

Metabolic acidosis is frequently observed in clinical practice, especially among critically ill patients and/or in the course of renal failure. Complex mechanisms are involved, in most cases identifiable by medical history, pathophysiology-based diagnostic reasoning and measure of some key acid-base parameters that are easily available or calculable. On this basis the bedside differential diagnosis of metabolic acidosis should be started from the identification of the two main subtypes of metabolic acidosis: the high anion gap metabolic acidosis and the normal anion gap (or hyperchloremic) metabolic acidosis. Metabolic acidosis, especially in its acute forms with elevated anion gap such as is the case of lactic acidosis, diabetic and acute intoxications, may significantly affect metabolic body homeostasis and patients hemodynamic status, setting the stage for true medical emergencies. The therapeutic approach should be first aimed at early correction of concurrent clinical problems (e.g. fluids and hemodynamic optimization in case of shock, mechanical ventilation in case of concomitant respiratory failure, hemodialysis for acute intoxications etc.), in parallel to the formulation of a diagnosis. In case of severe acidosis, the administration of alkalizing agents should be carefully evaluated, taking into account the risk of side effects, as well as the potential need of renal replacement therapy.

A life-threatening case of TAFRO syndrome with dramatic response to tocilizumab, rituximab, and pulse steroids: The first case report in Latin America.

PubMed

José, Fabio Freire; Kerbauy, Lucila Nassif; Perini, Guilherme Fleury; Blumenschein, Danielle Isadora; Pasqualin, Denise da Cunha; Malheiros, Denise Maria Avancini Costa; Campos Neto, Guilherme de Carvalho; de Souza Santos, Fabio Pires; Piovesan, Ronaldo; Hamerschlak, Nelson

2017-03-01

This is the report of the first case of TAFRO syndrome (Thrombocytopenia, Anasarca, myelofibrosis, Renal dysfunction, Organomegaly) in Latin America. The patient was a 61-year-old white woman of Ashkenazi Jewish descent, who presented with a history of 8 days of nausea, vomiting, and fever; severe pitting edema in both legs, ascites, splenomegaly, and palpable axillary lymph nodes. Abdominal computed tomography (CT) showed bilateral pleural effusion and retroperitoneal lymph node enlargement. Anasarca and worsening of renal function led to admission to the intensive care unit (ICU) with multiple organ failure, requiring mechanical ventilation, vasopressor medications, and continuous renal replacement therapy (CRRT). Diagnosis of TAFRO syndrome was made on day 18 after admission, based on clinical findings and results of bone marrow and lymph node biopsies. She was treated with methylprednisolone, tocilizumab, and rituximab. One week after the first tocilizumab dose, she had dramatic improvements in respiratory and hemodynamic status, and was weaned from ventilator support and vasopressor medications. After 2 weeks of therapy, CRRT was switched to intermittent hemodialysis. On day 46, the patient was discharged from the ICU to the general ward, and 3 months after admission, she went home. Provided the interleukin-6 measurement is available, this approach is suggested in cases of TAFRO syndrome, in order to customize the treatment.

Exercise excess pressure and exercise-induced albuminuria in patients with type 2 diabetes mellitus.

PubMed

Climie, Rachel E D; Srikanth, Velandai; Keith, Laura J; Davies, Justin E; Sharman, James E

2015-05-01

Exercise-induced albuminuria is common in patients with type 2 diabetes mellitus (T2DM) in response to maximal exercise, but the response to light-moderate exercise is unclear. Patients with T2DM have abnormal central hemodynamics and greater propensity for exercise hypertension. This study sought to determine the relationship between light-moderate exercise central hemodynamics (including aortic reservoir and excess pressure) and exercise-induced albuminuria. Thirty-nine T2DM (62 ± 9 yr; 49% male) and 39 nondiabetic controls (53 ± 9 yr; 51% male) were examined at rest and during 20 min of light-moderate cycle exercise (30 W; 50 revolutions/min). Albuminuria was assessed by the albumin-creatinine ratio (ACR) at rest and 30 min postexercise. Hemodynamics recorded included brachial and central blood pressure (BP), aortic stiffness, augmented pressure (AP), aortic reservoir pressure, and excess pressure integral (Pexcess). There was no difference in ACR between groups before exercise (P > 0.05). Exercise induced a significant rise in ACR in T2DM but not controls (1.73 ± 1.43 vs. 0.53 ± 1.0 mg/mol, P = 0.002). All central hemodynamic variables were significantly higher during exercise in T2DM (i.e., Pexcess, systolic BP and AP; P < 0.01 all). In T2DM (but not controls), exercise Pexcess was associated with postexercise ACR (r = 0.51, P = 0.002), and this relationship was independent of age, sex, body mass index, heart rate, aortic stiffness, antihypertensive medication, and ambulatory daytime systolic BP (β = 0.003, P = 0.003). Light-moderate exercise induced a significant rise in ACR in T2DM, and this was independently associated with Pexcess, a potential marker of vascular dysfunction. These novel findings suggest that Pexcess could be important for appropriate renal function in T2DM. Copyright © 2015 the American Physiological Society.

Recent advances in the pathogenetic mechanisms of sepsis-associated acute kidney injury.

PubMed

Fani, Filippo; Regolisti, Giuseppe; Delsante, Marco; Cantaluppi, Vincenzo; Castellano, Giuseppe; Gesualdo, Loreto; Villa, Gianluca; Fiaccadori, Enrico

2018-06-01

Sepsis is a serious medical condition that can lead to multi-organ failure and shock, and it is associated with increased mortality. Acute kidney injury (AKI) is a frequent complication of sepsis in critically ill patients, and often requires renal replacement therapy. The pathophysiology of AKI in sepsis has not yet been fully defined. In the past, classic theories were mainly focused on systemic hemodynamic derangements, underscoring the key role of whole kidney hypoperfusion due to reduced renal blood flow. However, a growing body of experimental and clinical evidence now shows that, at least in the early phase of sepsis-associated AKI, renal blood flow is normal, or even increased. This could suggest a dissociation between renal blood flow and kidney function. In addition, the scant data available from kidney biopsies in human studies do not support diffuse acute tubular necrosis as the predominant lesion. Instead, increasing importance is now attributed to kidney damage resulting from a complex interaction between immunologic mechanisms, inflammatory cascade activation, and deranged coagulation pathways, leading to microvascular dysfunction, endothelial damage, leukocyte/platelet activation with the formation of micro-thrombi, epithelial tubular cell injury and dysfunction. Moreover, the same processes, through maladaptive responses leading to fibrosis acting from the very beginning, may set the stage for progression to chronic kidney disease in survivors from sepsis-associated AKI episodes. The aim of this narrative review is to summarize and discuss the latest evidence on the pathophysiological mechanisms involved in septic AKI, based on the most recent data from the literature.

An overview of glomerular filtration rate testing in dogs and cats

PubMed Central

Von Hendy-Willson, Vanessa E.; Pressler, Barrak M.

2010-01-01

Determination of glomerular filtration rate (GFR) is a valuable, yet underused, diagnostic tool for evaluating renal function in dogs and cats. This article first reviews the hormonal and hemodynamic factors which contribute to GFR, followed by a description of considerations when selecting a pharmacokinetic model and methods of animal-to-animal standardization. The best-characterized existing GFR markers, including creatinine, radiolabeled markers, and iohexol, are reviewed in depth, as well as alternative but lesser-used techniques. A weighted means analysis of reported GFR measurements in healthy dogs and cats and a review of selected studies that have examined GFR alterations in animals with naturally-occurring and experimental diseases provide the reader with preliminary guidelines on expected GFR results in these species and disease conditions. PMID:20541957

Intra-arterial nitroglycerin for intra-operative arterial vasospasm during pediatric renal transplantation.

PubMed

Penna, Frank J; Harvey, Elizabeth; John, Philip; Armstrong, Derek; Luginbuehl, Igor; Odeh, Rakan I; Alyami, Fahad; Koyle, Martin A; Lorenzo, Armando J

2016-05-01

Intra-operative arterial vasospasm during pediatric renal transplantation is an urgent clinical situation resulting in end-organ ischemia, associated changes in parenchymal turgor and color, diminished flow on ultrasound, and if left untreated, allograft loss. We hypothesized that intra-operative intra-arterial injection of nitroglycerin would reverse vasospasm and improve renal perfusion. A three-yr-old girl with end-stage renal disease due to autosomal recessive polycystic kidney disease on peritoneal dialysis underwent deceased donor renal transplantation. After optimal immediate reperfusion and hemodynamic parameters, the kidney lost turgor and became mottled in appearance despite adequate hilar arterial and venous Doppler waveforms. Two aliquots of 40 μg (0.4 mL of a 100 μg/mL) nitroglycerin solution were injected directly into the renal artery 10 min apart. Nitroglycerin resulted in dramatic change in the consistency and appearance of the allograft. An improvement in renal blood flow was demonstrated by ultrasound after the second intra-arterial nitroglycerin injection with only a transient decrease in systemic arterial blood pressure. The child experienced normal allograft perfusion on serial postoperative ultrasounds, with a prompt decrease in serum creatinine and excellent diuresis. Intra-arterial nitroglycerin is a promising option for intra-operative arterial vasospasm during pediatric renal transplantation with objective improvement in blood flow and perfusion. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Assessment of cisplatin-induced kidney injury using an integrated rodent platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Yafei; Brott, David; Luo, Wenli

Current diagnosis of drug-induced kidney injury (DIKI) primarily relies on detection of elevated plasma creatinine (Cr) or blood urea nitrogen (BUN) levels; however, both are indices of overall kidney function and changes are delayed with respect to onset of nephron injury. Our aim was to investigate whether early changes in new urinary DIKI biomarkers predict plasma Cr, BUN, renal hemodynamic and kidney morphological changes associated with kidney injury following a single dose of cisplatin (CDDP) using an integrated platform in rodent. Conscious surgically prepared male Han Wistar rats were given a single intraperitoneal dose of CDDP (15 mg/kg). Glomerular filtrationmore » rate (GFR), effective renal plasma flow (ERPF), urinalysis, DIKI biomarkers, CDDP pharmacokinetics, blood pressures, heart rate, body temperature and electroencephalogram (EEG) were measured in the same vehicle- or CDDP-treated animals over 72 h. Plasma chemistry (including Cr and BUN) and renal tissues were examined at study termination. Cisplatin caused progressive reductions of GFR, ERPF, heart rate and body temperature from day 1 (0–24 h). DIKI biomarkers including alpha-glutathione S-transferase (α-GST) significantly increased as early as 6 h post-dose, which preceded significant declines of GFR and ERPF (24 h), increased plasma Cr and BUN (72 h), and associated with renal acute tubular necrosis at 72 h post-dose. The present study adds to the current understanding of CDDP action by demonstrating that early increases in urinary excretion of α-GST predict DIKI risk following acute exposure to CDDP in rats, before changes in traditional DIKI markers are evident. - Highlights: ► CDDP causes direct damage to kidneys without affecting EEG or CVS function. ► α-GST and albumin detect DIKI earlier when compared with traditional indices. ► Integrated “cardiovascular-EEG-renal” model to better understand DIKI mechanisms ► Promotes 3R's principles in drug discovery and development.« less

CCKB/gastrin receptors mediate changes in sodium and potassium absorption in the isolated perfused rat kidney.

PubMed

von Schrenck, T; Ahrens, M; de Weerth, A; Bobrowski, C; Wolf, G; Jonas, L; Jocks, T; Schulz, M; Bläker, M; Neumaier, M; Stahl, R A

2000-09-01

To evaluate the function of cholecystokinin B (CCKB)/gastrin receptors in the rat kidney, we identified the receptors by Northern blot and localized the receptors by immunohistochemistry. The functional effects of gastrin were studied under standardized in vitro conditions using the isolated perfused kidney. Rat kidneys were mounted in an organ bath by attaching the renal artery to a perfusion system. A catheter was inserted into the renal vein and the ureter to collect samples that were analyzed for the concentrations of electrolytes. After a preperfusion period, gastrin-17-I was given via the renal artery (10-8 to 10-6 mol/L). Subsequently, hemodynamic parameters (for example, perfusate flow) and changes in sodium and potassium absorption were determined. All data were subjected to a nonparametric analysis of variance and, in case of significant results, to subsequent paired comparisons by the a posteriori Wilcoxon test. Northern blot analysis detected CCKB receptor transcripts in total RNA isolated from kidneys. Immunohistochemistry localized CCKB receptors on tubules and collecting duct cells. Compared with controls, gastrin (10-6 mol/L) caused a decrease in the fractional sodium reabsorption (basal 80%, 10 minutes after application of gastrin 71%, after 20 minutes 62%, P < 0.05). This effect was inhibited by the CCKB receptor antagonist L-365,260. Gastrin decreased urinary potassium excretion at 10-8 and 10-6 mol/L [maximal decrease at 10-6 mol/L from baseline values (100%) to 49% after 10 minutes and to 69% after 20 minutes, P < 0.05, N = 6]. This effect was also abolished by the CCKB receptor antagonist L-365,260. Gastrin (10-6 mol/L) reduced perfusate flow by 31% (P < 0.05). CCKB receptors are expressed in the rat kidney on tubules and collecting ducts. These receptors mediate changes in renal potassium and sodium absorption. In addition, gastrin causes a decrease in perfusate flow, indicating that CCKB receptors might also modulate vascular resistance in the kidney.

Studies on arterial stiffness and wave reflections in hypertension.

PubMed

Safar, Michel E; Levy, Bernard I

2015-01-01

Patho-physiological and pharmacological studies have consistently noticed that, with the exception of subjects with end-stage renal disease, total intravascular blood volume is not increased in patients with chronic hypertension. Because the mean circulatory pressure is enhanced in such subjects, it was postulated that the compliance of the cardiovascular system could be abnormally low in this particular population. This simple observation has influenced a great part of our experimental and clinical research directed toward subjects with hypertension and their relationship with the compliance of the vascular system. These works started between 1970 and 1980 by methodological investigations and validations followed by analysis of clinical situations that showed that venous and mostly arterial stiffness were significantly increased in hypertensive patients independently of blood pressure level. During the same time, we assessed the role of endothelium on the large arterial wall mechanical properties in normotensive and hypertensive rats. Thereafter more specific directions have been developed, affecting large arteries structure and function and arterial wall remodeling, including their consequences on central and peripheral hemodynamics. In parallel, epidemiological studies identified the pulsatile hemodynamic parameters as major independent predictors of cardiovascular risks. The consequences of these alterations on clinical pharmacology and therapeutics in hypertension are analyzed in detail. © American Journal of Hypertension, Ltd 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Splenic Injury During Percutaneous Nephrolithotomy

PubMed Central

Thomas, Anil A.; Pierce, Gregory; Walsh, R. Matthew; Sands, Mark

2009-01-01

Background: Injury to the spleen is a recognized complication during percutaneous renal access due to the close anatomical relationship of the spleen and the left kidney. However, transsplenic renal access is a rare complication of percutaneous nephrolithotomy and can also result in considerable morbidity, often requiring emergent splenectomy. Methods: We present our experience with splenic injury during percutaneous nephrolithotomy managed conservatively with the use of a collagen-thrombin hemostatic sealant (D-Stat; Vascular Solutions, Inc., Minneapolis, MN) after delayed removal of the nephrostomy tubes. Results: The patient had an uneventful recovery and was discharged home on postoperative day 6. Conclusion: In select hemodynamically stable patients, nonoperative management with the adjunctive use of hemostatic sealants may be considered. PMID:19660224

Tissue-specific modulation of angiotensin-converting enzyme (ACE) in hyperthyroidism.

PubMed

Carneiro-Ramos, M S; Silva, V B; Santos, R A S; Barreto-Chaves, M L M

2006-11-01

We have previously demonstrated the interaction between the RAS and thyroid hormones (TH). The present study was designed to determine the role of TH in the local regulation of ACE activity and expression in different tissues. Adult male Wistar rats were randomized into three groups: T4-25 and T4-100 (0.025 and 0.100mg/kg of body weight/day of l-thyroxine for 14 days, respectively) and control. Hemodynamic parameters as well as cardiac and renal hypertrophy were evaluated. ACE activity and mRNA levels were determined by Fluorimetric and Northern blot assays, respectively. Both doses increased SBP and HR, as well as inducing cardiac and renal hypertrophy. Pulmonary and serum ACE levels were comparable among the groups. Both doses promoted increased renal ACE activity and expression but surprisingly ACE was diminished in the heart in both hyperthyroid groups. This change was mediated by a tissue-specific transcription mechanism.

Emerging drugs for chronic kidney disease.

PubMed

Stefoni, Sergio; Cianciolo, Giuseppe; Baraldi, Olga; Iorio, Mario; Angelini, Maria Laura

2014-06-01

Chronic kidney disease (CKD) is a worldwide health problem. Despite remarkable headway in slowing the progression of kidney diseases, the incidence of end-stage renal disease (ESRD) is increasing in all countries with a severe impact on patients and society. The high incidence of diabetes and hypertension, along with the aging population, may partially explain this growth. Currently, the mainstay of pharmacological treatment for CKD, aiming to slow progression to ESRD are ACE inhibitors and angiotensin II receptor blockers for their hemodynamic/antihypertensive and anti-inflammatory/antifibrotic action. However, novel drugs would be highly desirable to effectively slow the progressive renal function loss. Through the search engines, PubMed and ClinicalTrial.gov, the scientific literature was reviewed in search of emerging drugs in Phase II or III trials, which appear to be the most promising for CKD treatment. The great expectations for new drugs for the management of CKD over the last decade have unfortunately not been met. Encouraging results from preliminary studies with specific agents need to be tempered with caution, given the absence of consistent and adequate data. To date, several agents that showed great promise in animal studies have been less effective in humans.

Reactivity of hemodynamic responses and functional connectivity to different states of alpha synchrony: a concurrent EEG-fMRI study.

PubMed

Wu, Lei; Eichele, Tom; Calhoun, Vince D

2010-10-01

Concurrent EEG-fMRI studies have provided increasing details of the dynamics of intrinsic brain activity during the resting state. Here, we investigate a prominent effect in EEG during relaxed resting, i.e. the increase of the alpha power when the eyes are closed compared to when the eyes are open. This phenomenon is related to changes in thalamo-cortical and cortico-cortical synchronization. In order to investigate possible changes to EEG-fMRI coupling and fMRI functional connectivity during the two states we adopted a data-driven approach that fuses the multimodal data on the basis of parallel ICA decompositions of the fMRI data in the spatial domain and of the EEG data in the spectral domain. The power variation of a posterior alpha component was used as a reference function to deconvolve the hemodynamic responses from occipital, frontal, temporal, and subcortical fMRI components. Additionally, we computed the functional connectivity between these components. The results showed widespread alpha hemodynamic responses and high functional connectivity during eyes-closed (EC) rest, while eyes open (EO) resting abolished many of the hemodynamic responses and markedly decreased functional connectivity. These data suggest that generation of local hemodynamic responses is highly sensitive to state changes that do not involve changes of mental effort or awareness. They also indicate the localized power differences in posterior alpha between EO and EC in resting state data are accompanied by spatially widespread amplitude changes in hemodynamic responses and inter-regional functional connectivity, i.e. low frequency hemodynamic signals display an equivalent of alpha reactivity. Copyright 2010 Elsevier Inc. All rights reserved.

Hyperfiltration-mediated injury in the remaining kidney of a transplant donor.

PubMed

Srivastava, Tarak; Hariharan, Sundaram; Alon, Uri S; McCarthy, Ellen T; Sharma, Ram; El-Meanawy, Ashraf; Savin, Virginia J; Sharma, Mukut

2018-05-29

Kidney donors face a small but definite risk of end-stage renal disease 15-30 years postdonation. The development of proteinuria, hypertension with gradual decrease in kidney function in the donor after surgical resection of 1 kidney has been attributed to hyperfiltration. Genetic variations, physiological adaptations, and co-morbidities exacerbate the hyperfiltration-induced loss of kidney function in the years following donation. A focus on glomerular hemodynamics and capillary pressure has led to the development of drugs that target the renin-angiotensin-aldosterone system (RAAS), but these agents yield mixed results in transplant recipients and donors. Recent work on glomerular biomechanical forces highlights the differential effects of tensile stress and fluid flow shear stress (FFSS) from hyperfiltration. Capillary wall stretch due to glomerular capillary pressure increases tensile stress on podocyte foot processes that cover the capillary. In parallel, increased flow of the ultrafiltrate due to single nephron glomerular filtration rate elevates FFSS on the podocyte cell body. While tensile stress invokes the RAAS, FFSS predominantly activates the COX2-PGE2-EP2 axis. Distinguishing these 2 mechanisms is critical, as current therapeutic approaches focus on the RAAS system. A better understanding of the biomechanical forces can lead to novel therapeutic agents to target FFSS through the COX2-PGE2-EP2 axis in hyperfiltration-mediated injury. We present an overview of several aspects of the risk to transplant donors and discuss the relevance of FFSS in podocyte injury, loss of glomerular barrier function leading to albuminuria and gradual loss of renal function, and potential therapeutic strategies to mitigate hyperfiltration-mediated injury to the remaining kidney.

Losartan prevents the imbalance between renal dopaminergic and renin angiotensin systems induced by fructose overload. L-dopa/dopamine index as new potential biomarker of renal dysfunction.

PubMed

Mikusic, Natalia Lucía Rukavina; Kouyoumdzian, Nicolás Martín; Uceda, Ana; Del Mauro, Julieta Sofía; Pandolfo, Marcela; Gironacci, Mariela Mercedes; Puyó, Ana María; Toblli, Jorge Eduardo; Fernández, Belisario Enrique; Choi, Marcelo Roberto

2018-05-01

The renin angiotensin system (RAS) and the renal dopaminergic system (RDS) act as autocrine and paracrine systems to regulate renal sodium management and inflammation and their alterations have been associated to hypertension and renal damage. Nearly 30-50% of hypertensive patients have insulin resistance (IR), with a strong correlation between hyperinsulinemia and microalbuminuria. The aim of this study was to demonstrate the existence of an imbalance between RAS and RDS associated to IR, hypertension and kidney damage induced by fructose overload (FO), as well as to establish their prevention, by pharmacological inhibition of RAS with losartan. Ninety-six male Sprague-Dawley rats were randomly divided into four groups and studied at 4, 8 and 12 weeks: control group (C4, C8 and C12; tap water to drink); fructose-overloaded group (F4, F8 and F12; 10% w/v fructose solution to drink); losartan-treated control (L) group (L4, L8 and L12; losartan 30 mg/kg/day, in drinking water); and fructose-overloaded plus losartan group (F + L4, F + L8 and F + L12, in fructose solution). FO induced metabolic and hemodynamic alterations as well as an imbalance between RAS and RDS, characterized by increased renal angiotensin II levels and AT 1 R overexpression, reduced urinary excretion of dopamine, increased excretion of L-dopa (increased L-dopa/dopamine index) and down-regulation of D 1 R and tubular dopamine transporters OCT-2, OCT-N1 and total OCTNs. This imbalance was accompanied by an overexpression of renal tubular Na + , K + -ATPase, pro-inflammatory (NF-kB, TNF-α, IL-6) and pro-fibrotic (TGF-β1 and collagen) markers and by renal damage (microalbuminuria and reduced nephrin expression). Losartan prevented the metabolic and hemodynamic alterations induced by FO from week 4. Increased urinary L-dopa/dopamine index and decreased D 1 R renal expression associated to FO were also prevented by losartan since week 4. The same pattern was observed for renal expression of OCTs/OCTNs, Na + , K + -ATPase, pro-inflammatory and pro-fibrotic markers from week 8. The appearance of microalbuminuria and reduced nephrin expression was prevented by losartan at week 12. The results of this study provide new insight regarding the mechanisms by which a pro-hypertensive and pro-inflammatory system, such as RAS, downregulates another anti-hypertensive and anti-inflammatory system such as RDS. Additionally, we propose the use of L-dopa/dopamine index as a biochemical marker of renal dysfunction in conditions characterized by sodium retention, IR and/or hypertension, and as a predictor of response to treatment and follow-up of these processes. Copyright © 2018. Published by Elsevier Inc.

Effect of sodium intake on sympathetic and hemodynamic response to thermal receptor stimulation.

PubMed

DiBona, Gerald F; Jones, Susan Y

2003-02-01

Low dietary sodium intake increases central nervous system angiotensin activity, which increases basal renal sympathetic nerve activity and shifts its arterial baroreflex control to a higher level of arterial pressure. This results in a higher level of renal sympathetic nerve activity for a given level of arterial pressure during low dietary sodium intake than during either normal or high dietary sodium intake, in which there is less central angiotensin activity. Peripheral thermal receptor stimulation overrides arterial baroreflex control and produces a pressor response, tachycardia, increased renal sympathetic nerve activity, and renal vasoconstriction. To test the hypothesis that increased central angiotensin activity would enhance the responses to peripheral thermal receptor stimulation, anesthetized normal rats in balance on low, normal, and high dietary sodium intake were subjected to acute peripheral thermal receptor stimulation. Low sodium rats had greater increases in renal sympathetic nerve activity, greater decreases in RBF, and greater increases in renal vascular resistance than high sodium rats. Responses of normal sodium rats were between those of low and high sodium rats. Arterial pressure and heart rate responses were not different among dietary groups. Spontaneously hypertensive rats, known to have increased central nervous system angiotensin activity, also had greater renal sympathoexcitatory and vasoconstrictor responses than normotensive Wistar-Kyoto rats. These results support the view that increased central nervous system angiotensin activity alters arterial baroreflex control of renal sympathetic nerve activity such that the renal sympathoexcitatory and vasoconstrictor responses to peripheral thermoreceptor stimulation are enhanced.

Simultaneous characterization of metabolic, cardiac, vascular and renal phenotypes of lean and obese SHHF rats.

PubMed

Youcef, Gina; Olivier, Arnaud; L'Huillier, Clément P J; Labat, Carlos; Fay, Renaud; Tabcheh, Lina; Toupance, Simon; Rodriguez-Guéant, Rosa-Maria; Bergerot, Damien; Jaisser, Frédéric; Lacolley, Patrick; Zannad, Faiez; Laurent Vallar; Pizard, Anne

2014-01-01

Individuals with metabolic syndrome (MetS) are prone to develop heart failure (HF). However, the deleterious effects of MetS on the continuum of events leading to cardiac remodeling and subsequently to HF are not fully understood. This study characterized simultaneously MetS and cardiac, vascular and renal phenotypes in aging Spontaneously Hypertensive Heart Failure lean (SHHF(+/?) regrouping (+/+) and (+/cp) rats) and obese (SHHF(cp/cp), "cp" defective mutant allele of the leptin receptor gene) rats. We aimed to refine the milestones and their onset during the progression from MetS to HF in this experimental model. We found that SHHF(cp/cp )but not SHHF(+/?) rats developed dyslipidemia, as early as 1.5 months of age. This early alteration in the lipidic profile was detectable concomitantly to impaired renal function (polyuria, proteinuria but no glycosuria) and reduced carotid distensibility as compared to SHHF(+/?) rats. By 3 months of age SHHFcp/cp animals developed severe obesity associated with dislipidemia and hypertension defining the onset of MetS. From 6 months of age, SHHF(+/?) rats developed concentric left ventricular hypertrophy (LVH) while SHHF(cp/cp) rats developed eccentric LVH apparent from progressive dilation of the LV dimensions. By 14 months of age only SHHF(cp/cp) rats showed significantly higher central systolic blood pressure and a reduced ejection fraction resulting in systolic dysfunction as compared to SHHF(+/?). In summary, the metabolic and hemodynamic mechanisms participating in the faster decline of cardiac functions in SHHF(cp/cp) rats are established long before their physiological consequences are detectable. Our results suggest that the molecular mechanisms triggered within the first three months after birth of SHHF(cp/cp) rats should be targeted preferentially by therapeutic interventions in order to mitigate the later HF development.

Simultaneous Characterization of Metabolic, Cardiac, Vascular and Renal Phenotypes of Lean and Obese SHHF Rats

PubMed Central

Youcef, Gina; Olivier, Arnaud; L'Huillier, Clément P. J.; Labat, Carlos; Fay, Renaud; Tabcheh, Lina; Toupance, Simon; Rodriguez-Guéant, Rosa-Maria; Bergerot, Damien; Jaisser, Frédéric; Lacolley, Patrick; Zannad, Faiez; Laurent Vallar; Pizard, Anne

2014-01-01

Individuals with metabolic syndrome (MetS) are prone to develop heart failure (HF). However, the deleterious effects of MetS on the continuum of events leading to cardiac remodeling and subsequently to HF are not fully understood. This study characterized simultaneously MetS and cardiac, vascular and renal phenotypes in aging Spontaneously Hypertensive Heart Failure lean (SHHF+/? regrouping +/+ and +/cp rats) and obese (SHHFcp/cp, “cp” defective mutant allele of the leptin receptor gene) rats. We aimed to refine the milestones and their onset during the progression from MetS to HF in this experimental model. We found that SHHFcp/cp but not SHHF+/? rats developed dyslipidemia, as early as 1.5 months of age. This early alteration in the lipidic profile was detectable concomitantly to impaired renal function (polyuria, proteinuria but no glycosuria) and reduced carotid distensibility as compared to SHHF+/? rats. By 3 months of age SHHFcp/cp animals developed severe obesity associated with dislipidemia and hypertension defining the onset of MetS. From 6 months of age, SHHF+/? rats developed concentric left ventricular hypertrophy (LVH) while SHHFcp/cp rats developed eccentric LVH apparent from progressive dilation of the LV dimensions. By 14 months of age only SHHFcp/cp rats showed significantly higher central systolic blood pressure and a reduced ejection fraction resulting in systolic dysfunction as compared to SHHF+/?. In summary, the metabolic and hemodynamic mechanisms participating in the faster decline of cardiac functions in SHHFcp/cp rats are established long before their physiological consequences are detectable. Our results suggest that the molecular mechanisms triggered within the first three months after birth of SHHFcp/cp rats should be targeted preferentially by therapeutic interventions in order to mitigate the later HF development. PMID:24831821

Computational Simulations of Inferior Vena Cava (IVC) Filter Placement and Hemodynamics in Patient-Specific Geometries

NASA Astrophysics Data System (ADS)

Aycock, Kenneth; Sastry, Shankar; Kim, Jibum; Shontz, Suzanne; Campbell, Robert; Manning, Keefe; Lynch, Frank; Craven, Brent

2013-11-01

A computational methodology for simulating inferior vena cava (IVC) filter placement and IVC hemodynamics was developed and tested on two patient-specific IVC geometries: a left-sided IVC, and an IVC with a retroaortic left renal vein. Virtual IVC filter placement was performed with finite element analysis (FEA) using non-linear material models and contact modeling, yielding maximum vein displacements of approximately 10% of the IVC diameters. Blood flow was then simulated using computational fluid dynamics (CFD) with four cases for each patient IVC: 1) an IVC only, 2) an IVC with a placed filter, 3) an IVC with a placed filter and a model embolus, all at resting flow conditions, and 4) an IVC with a placed filter and a model embolus at exercise flow conditions. Significant hemodynamic differences were observed between the two patient IVCs, with the development of a right-sided jet (all cases) and a larger stagnation region (cases 3-4) in the left-sided IVC. These results support further investigation of the effects of IVC filter placement on a patient-specific basis.

Comparative study of the efficacy and safety of paracetamol, ibuprofen, and indomethacin in closure of patent ductus arteriosus in preterm neonates.

PubMed

El-Mashad, Abd El-Rahman; El-Mahdy, Heba; El Amrousy, Doaa; Elgendy, Marwa

2017-02-01

In this prospective study, we compared the efficacy and side effects of indomethacin, ibuprofen, and paracetamol in patent ductus arteriosus (PDA) closure in preterm neonates. Three hundred preterm neonates with hemodynamically significant PDA (hs-PDA) admitted at our neonatal intensive care unit were enrolled in the study. They were randomized into three groups. Group I (paracetamol group) received 15 mg/kg/6 h IV paracetamol infusion for 3 days. Group II (ibuprofen group) received 10 mg/kg IV ibuprofen infusion followed by 5 mg/kg/day for 2 days. Group III (indomethacin group) received 0.2 mg/kg/12 h indomethacin IV infusion for three doses. Laboratory investigations such as renal function test, liver function test, complete blood count, and blood gases were conducted in addition to echocardiographic examinations. All investigations were done before and 3 days after treatment. There was no significant difference between all groups regarding efficacy of PDA closure (P = 0.868). There was a significant increase in serum creatinine levels and serum blood urea nitrogen (BUN) in the ibuprofen and indomethacin groups (P < 0.001). There was a significant reduction in platelet count and urine output (UOP) in both ibuprofen and indomethacin groups (P < 0.001). There was a significant increase in bilirubin levels in only the ibuprofen group (P = 0.003). No significant difference of hemoglobin (HB) level or liver enzymes in all groups (P > 0.05). Ventilatory settings improved significantly in patients with successful closure of PDA than those with failed PDA closure (P < 0.001). Paracetamol is as effective as indomethacin and ibuprofen in closure of PDA in preterm neonates and has less side effects mainly on renal function, platelet count, and GIT bleeding. What is Known: • Hemodynamically significant patent ductus arteriosus has many complications for preterm and low birth weight neonates and better to be closed. Many drugs were used for medical closure of PDA e.g. indomethacin, ibuprofen and recently paracetamol. Many studies compare safety and efficacy of paracetamol with either indomethacin or ibuprofen. What is New: • It is the first large study that compares the efficacy and side effects of the three drugs in one study.

A longitudinal study of the control of renal and uterine hemodynamic changes of pregnancy.

PubMed

Ogueh, Onome; Clough, Angela; Hancock, Maggie; Johnson, Mark R

2011-01-01

We have determined the sequence and extent of maternal renal and uterine adaptation to pregnancy and examined the role of hormonal factors in their regulation. Renal bipolar diameter (RBD), renal artery resistance index (RARI), uterine artery pulsatility index (UAPI), and plasma relaxin, human chorionic gonadotropin (hCG), progesterone, estradiol, urea, and creatinine were measured longitudinally in women with normal spontaneous singleton pregnancies, in vitro fertilization (IVF) singleton pregnancies, ovum donation (OD) singleton pregnancies, and multiple pregnancies from prepregnancy to postpartum. There was a progressive increase in the RBD and the RARI and a decrease in the UAPI during pregnancy. These changes reversed toward prepregnancy levels by 6 weeks post delivery. There was no difference in the rate of change of RBD, RARI, and UAPI between spontaneous singleton, IVF singleton, OD singleton, and multiple pregnancies (p < 0.05), but relaxin was directly correlated to the RARI (r = 0.654, p = 0.015), and progesterone was inversely correlated to uterine artery PI (r = 0.554, p = 0.049). These data show that renal size and resistance to blood flow increase with advancing gestation, whereas the uterine artery resistance declined with gestation. These changes may be influenced by relaxin and progesterone.

4-Phenylbutyric Acid Reveals Good Beneficial Effects on Vital Organ Function via Anti-Endoplasmic Reticulum Stress in Septic Rats.

PubMed

Liu, Liangming; Wu, Huiling; Zang, JiaTao; Yang, Guangming; Zhu, Yu; Wu, Yue; Chen, Xiangyun; Lan, Dan; Li, Tao

2016-08-01

Sepsis and septic shock are the common complications in ICUs. Vital organ function disorder contributes a critical role in high mortality after severe sepsis or septic shock, in which endoplasmic reticulum stress plays an important role. Whether anti-endoplasmic reticulum stress with 4-phenylbutyric acid is beneficial to sepsis and the underlying mechanisms are not known. Laboratory investigation. State Key Laboratory of Trauma, Burns and Combined Injury. Sprague-Dawley rats. Using cecal ligation and puncture-induced septic shock rats, lipopolysaccharide-treated vascular smooth muscle cells, and cardiomyocytes, effects of 4-phenylbutyric acid on vital organ function and the relationship with endoplasmic reticulum stress and endoplasmic reticulum stress-mediated inflammation, apoptosis, and oxidative stress were observed. Conventional treatment, including fluid resuscitation, vasopressin, and antibiotic, only slightly improved the hemodynamic variable, such as mean arterial blood pressure and cardiac output, and slightly improved the vital organ function and the animal survival of septic shock rats. Supplementation of 4-phenylbutyric acid (5 mg/kg; anti-endoplasmic reticulum stress), especially administered at early stage, significantly improved the hemodynamic variables, vital organ function, such as liver, renal, and intestinal barrier function, and animal survival in septic shock rats. 4-Phenylbutyric acid application inhibited the endoplasmic reticulum stress and endoplasmic reticulum stress-related proteins, such as CCAAT/enhancer-binding protein homologous protein in vital organs, such as heart and superior mesenteric artery after severe sepsis. Further studies showed that 4-phenylbutyric acid inhibited endoplasmic reticulum stress-mediated cytokine release, apoptosis, and oxidative stress via inhibition of nuclear factor-κB, caspase-3 and caspase-9, and increasing glutathione peroxidase and superoxide dismutase expression, respectively. Anti-endoplasmic reticulum stress with 4-phenylbutyric acid is beneficial to septic shock. This beneficial effect of 4-phenylbutyric acid is closely related to the inhibition of endoplasmic reticulum stress-mediated oxidative stress, apoptosis, and cytokine release. This finding provides a potential therapeutic measure for clinical critical conditions, such as severe sepsis.

Renal hemodynamic effects of activation of specific renal sympathetic nerve fiber groups.

PubMed

DiBona, G F; Sawin, L L

1999-02-01

To examine the effect of activation of a unique population of renal sympathetic nerve fibers on renal blood flow (RBF) dynamics, anesthetized rats were instrumented with a renal sympathetic nerve activity (RSNA) recording electrode and an electromagnetic flow probe on the ipsilateral renal artery. Peripheral thermal receptor stimulation (external heat) was used to activate a unique population of renal sympathetic nerve fibers and to increase total RSNA. Total RSNA was reflexly increased to the same degree with somatic receptor stimulation (tail compression). Arterial pressure and heart rate were increased by both stimuli. Total RSNA was increased to the same degree by both stimuli but external heat produced a greater renal vasoconstrictor response than tail compression. Whereas both stimuli increased spectral density power of RSNA at both cardiac and respiratory frequencies, modulation of RBF variability by fluctuations of RSNA was small at these frequencies, with values for the normalized transfer gain being approximately 0.1 at >0.5 Hz. During tail compression coherent oscillations of RSNA and RBF were found at 0.3-0.4 Hz with normalized transfer gain of 0.33 +/- 0.02. During external heat coherent oscillations of RSNA and RBF were found at both 0.2 and 0.3-0.4 Hz with normalized transfer gains of 0. 63 +/- 0.05 at 0.2 Hz and 0.53 +/- 0.04 to 0.36 +/- 0.02 at 0.3-0.4 Hz. Renal denervation eliminated the oscillations in RBF at both 0.2 and 0.3-0.4 Hz. These findings indicate that despite similar increases in total RSNA, external heat results in a greater renal vasoconstrictor response than tail compression due to the activation of a unique population of renal sympathetic nerve fibers with different frequency-response characteristics of the renal vasculature.

Pathophysiology and Toxicokinetic Studies of Blue-Green Algae Intoxication in the Swine Model

DTIC Science & Technology

1991-06-26

perfusion, renal perfusion, and mean arterial and central venous pressures were decreased, and portal pressure increased. Liver iron and hemoglobin indicated...the lethal dose, aortic mean pressure and central venous pressure decreased significantly, while portal venous pressure significantly increased. The...8217" recorded on a poiygraphY and logged on a hemodynamic analyzer.𔄁 Mean aortic, central venous , and portal venous pressures were determined predosing

Vestibular stimulation leads to distinct hemodynamic patterning

NASA Technical Reports Server (NTRS)

Kerman, I. A.; Emanuel, B. A.; Yates, B. J.

2000-01-01

Previous studies demonstrated that responses of a particular sympathetic nerve to vestibular stimulation depend on the type of tissue the nerve innervates as well as its anatomic location. In the present study, we sought to determine whether such precise patterning of vestibulosympathetic reflexes could lead to specific hemodynamic alterations in response to vestibular afferent activation. We simultaneously measured changes in systemic blood pressure and blood flow (with the use of Doppler flowmetry) to the hindlimb (femoral artery), forelimb (brachial artery), and kidney (renal artery) in chloralose-urethane-anesthetized, baroreceptor-denervated cats. Electrical vestibular stimulation led to depressor responses, 8 +/- 2 mmHg (mean +/- SE) in magnitude, that were accompanied by decreases in femoral vasoconstriction (23 +/- 4% decrease in vascular resistance or 36 +/- 7% increase in vascular conductance) and increases in brachial vascular tone (resistance increase of 10 +/- 6% and conductance decrease of 11 +/- 4%). Relatively small changes (<5%) in renal vascular tone were observed. In contrast, electrical stimulation of muscle and cutaneous afferents produced pressor responses (20 +/- 6 mmHg) that were accompanied by vasoconstriction in all three beds. These data suggest that vestibular inputs lead to a complex pattern of cardiovascular changes that is distinct from that which occurs in response to activation of other types of somatic afferents.

Exogenous L-Arginine Attenuates the Effects of Angiotensin II on Renal Hemodynamics and the Pressure Natriuresis-Diuresis Relationship

PubMed Central

Das, Satarupa; Mattson, David L.

2014-01-01

SUMMARY Administration of exogenous L-Arginine (L-Arg) attenuates Angiotensin II (AngII)-mediated hypertension and kidney disease in rats. The present study assessed renal hemodynamics and pressure-diuresis-natriuresis in anesthetized rats infused with vehicle, AngII (20 ng/kg/min, iv) or AngII + L-Arg (300 µg/kg/min, iv). Increasing renal perfusion pressure (RPP) from approximately 100 to 140 mmHg resulted in a 9–10 fold increase in urine flow and sodium excretion rate in control animals. In comparison, AngII infusion significantly reduced renal blood flow (RBF) and glomerular filtration rate (GFR) by 40–42% and blunted the pressure-dependent increase in urine flow and sodium excretion rate by 54–58% at elevated RPP. Supplementation of L-Arg reversed the vasoconstrictor effects of AngII and restored pressure-dependent diuresis to levels not significantly different from control rats. Experiments in isolated aortic rings were performed to assess L-Arg effects on the vasculature. Dose-dependent contraction to AngII (10−10M to 10−7M) was observed with a maximal force equal to 27±3% of the response to 10−5M phenylephrine. Contraction to 10−7M AngII was blunted by 75±3% with 10−4M L-Arg. The influence of L-Arg to blunt AngII mediated contraction was eliminated by endothelial denudation or incubation with nitric oxide synthase inhibitors. Moreover, the addition of 10−3M cationic or neutral amino acids, which compete with L-Arg for cellular uptake, blocked the effect of L-Arg. Anionic amino acids did not influence the effects of L-Arg on AngII-mediated contraction. These studies indicate that L-Arg blunts AngII-mediated vascular contraction by an endothelial- and NOS-dependent mechanism involving cellular uptake of L-Arg. PMID:24472006

Utility of Functional Hemodynamics and Echocardiography to Aid Diagnosis and Management of Shock.

PubMed

McGee, William T; Raghunathan, Karthik; Adler, Adam C

2015-12-01

The utility of functional hemodynamics and bedside ultrasonography is increasingly recognized as advantageous for both improved diagnosis and management of shock states. In contrast to conventional "static" measures, "dynamic" hemodynamic measures and bedside imaging modalities enhance pathophysiology-based comprehensive understanding of shock states and the response to therapy. The current editions of major textbooks in the primary specialties--in which clinicians routinely encounter patients in shock--including surgery, anesthesia, emergency medicine, and internal medicine continue to incorporate traditional (conventional) descriptions of shock that use well-described (but potentially misleading) intravascular pressures to classify shock states. Reliance on such intravascular pressure measurements is not as helpful as newer "dynamic" functional measures including ultrasonography to both better assess volume responsiveness and biventricular cardiac function. This review thus emphasizes the application of current functional hemodynamics and ultrasonography to the diagnosis and management of shock as a contrast to conventional "static" pressure-based measures.

Cerebrovascular Accidents Associated with Sorafenib in Hepatocellular Carcinoma

PubMed Central

Saif, Muhammad W.; Isufi, Iris; Peccerillo, Jennifer; Syrigos, Kostas N.

2011-01-01

Sorafenib is an oral angiogenetic multikinase inhibitor approved in the treatment of renal and hepatocellular carcinoma. Bleeding and venous thrombotic events have been described with angiogenetic agents but cerebrovascular accidents are rarely reported. We report two cases of patients with hepatocellular carcinoma who developed a cerebrovascular accident while on sorafenib. Neither patient had any risk factors for the cerebrovascular events apart from gender and age in the second patient. Laboratory data were noncontributory. The head CT scan did not reveal acute abnormalities. No hemodynamically significant stenosis was visible in the carotid ultrasound, and the echocardiogram showed normal size of the heart chambers and normal systolic function of the left ventricle. Sorafenib was discontinued in both cases. Physicians should monitor patients receiving sorafenib for neurologic symptoms, and in the absence of other etiology, prompt discontinuation of this drug should be considered. PMID:21687621

Cerebrovascular accidents associated with sorafenib in hepatocellular carcinoma.

PubMed

Saif, Muhammad W; Isufi, Iris; Peccerillo, Jennifer; Syrigos, Kostas N

2011-01-01

Sorafenib is an oral angiogenetic multikinase inhibitor approved in the treatment of renal and hepatocellular carcinoma. Bleeding and venous thrombotic events have been described with angiogenetic agents but cerebrovascular accidents are rarely reported. We report two cases of patients with hepatocellular carcinoma who developed a cerebrovascular accident while on sorafenib. Neither patient had any risk factors for the cerebrovascular events apart from gender and age in the second patient. Laboratory data were noncontributory. The head CT scan did not reveal acute abnormalities. No hemodynamically significant stenosis was visible in the carotid ultrasound, and the echocardiogram showed normal size of the heart chambers and normal systolic function of the left ventricle. Sorafenib was discontinued in both cases. Physicians should monitor patients receiving sorafenib for neurologic symptoms, and in the absence of other etiology, prompt discontinuation of this drug should be considered.

Caring for critically ill oldest old patients: a clinical review.

PubMed

Vargas, Nicola; Tibullo, Loredana; Landi, Emanuela; Carifi, Giovanni; Pirone, Alfonso; Pippo, Antonio; Alviggi, Immacolata; Tizzano, Renato; Salsano, Elisa; Di Grezia, Francesco; Vargas, Maria

2017-10-01

Despite technological advances, the mortality rate for critically ill oldest old patients remains high. The intensive caring should be able to combine technology and a deep humanity considering that the patients are living the last part of their lives. In addition to the traditional goals of ICU of reducing morbidity and mortality, of maintaining organ functions and restoring health, caring for seriously oldest old patients should take into account their end-of-life preferences, the advance or proxy directives if available, the prognosis, the communication, their life expectancy and the impact of multimorbidity. The aim of this review was to focus on all these aspects with an emphasis on some intensive procedures such as mechanical ventilation, noninvasive mechanical ventilation, cardiopulmonary resuscitation, renal replacement therapy, hemodynamic support, evaluation of delirium and malnutrition in this heterogeneous frail ICU population.

Direct cortical hemodynamic mapping of somatotopy of pig nostril sensation by functional near-infrared cortical imaging (fNCI).

PubMed

Uga, Minako; Saito, Toshiyuki; Sano, Toshifumi; Yokota, Hidenori; Oguro, Keiji; Rizki, Edmi Edison; Mizutani, Tsutomu; Katura, Takusige; Dan, Ippeita; Watanabe, Eiju

2014-05-01

Functional near-infrared spectroscopy (fNIRS) is a neuroimaging technique for the noninvasive monitoring of human brain activation states utilizing the coupling between neural activity and regional cerebral hemodynamics. Illuminators and detectors, together constituting optodes, are placed on the scalp, but due to the presence of head tissues, an inter-optode distance of more than 2.5cm is necessary to detect cortical signals. Although direct cortical monitoring with fNIRS has been pursued, a high-resolution visualization of hemodynamic changes associated with sensory, motor and cognitive neural responses directly from the cortical surface has yet to be realized. To acquire robust information on the hemodynamics of the cortex, devoid of signal complications in transcranial measurement, we devised a functional near-infrared cortical imaging (fNCI) technique. Here we demonstrate the first direct functional measurement of temporal and spatial patterns of cortical hemodynamics using the fNCI technique. For fNCI, inter-optode distance was set at 5mm, and light leakage from illuminators was prevented by a special optode holder made of a light-shielding rubber sheet. fNCI successfully detected the somatotopy of pig nostril sensation, as assessed in comparison with concurrent and sequential somatosensory-evoked potential (SEP) measurements on the same stimulation sites. Accordingly, the fNCI system realized a direct cortical hemodynamic measurement with a spatial resolution comparable to that of SEP mapping on the rostral region of the pig brain. This study provides an important initial step toward realizing functional cortical hemodynamic monitoring during neurosurgery of human brains. Copyright © 2014. Published by Elsevier Inc.

Effects of renal sympathetic denervation on cardiac sympathetic activity and function in patients with therapy resistant hypertension.

PubMed

van Brussel, Peter M; Eeftinck Schattenkerk, Daan W; Dobrowolski, Linn C; de Winter, Robbert J; Reekers, Jim A; Verberne, Hein J; Vogt, Liffert; van den Born, Bert-Jan H

2016-01-01

Renal sympathetic denervation (RSD) is currently being investigated in multiple studies of sympathetically driven cardiovascular diseases such as heart failure and arrhythmias. Our aim was to assess systemic and cardiac sympatholytic effects of RSD by the measurement of cardiac sympathetic activity and cardiovascular parameters. A total of 21 consecutive patients with refractory hypertension (daytime ambulatory blood pressure (BP)≥150/100 mmHg despite the use of 3 or more antihypertensive drugs), no evidence for secondary hypertension and normal renovascular anatomy were included. RSD was performed with the Medtronic Symplicity renal denervation catheter with an average of 4.2 (range 3-6) ablations per renal artery. To assess cardiac sympathetic activity, 123I-mIBG cardiac scintigraphy was performed before and 6 weeks after. In addition, the effect of RSD on peripheral BP and cardiac hemodynamics were assessed non-invasively. 123I-mIBG uptake before and after RSD was 1.7±0.4% vs. 1.7±0.5% at 15 min. and 1.4±0.4% vs. 1.5±0.5% after 4 h. As a consequence, washout rate was similar before (33.7±11.7%) and after RSD (30.1±12.6%, p=0.27). In line with earlier RSD studies, a significant drop in systolic office BP (-12.2 mmHg, p=0.04) was detected, whereas the decrease in ambulatory BP was not significant. No changes were seen in heart rate, stroke volume or left ventricular contractility, both in supine position and after standing. In concert with previous reports, RSD leads to a significant drop in office BP. However, a reduction in sympathetic activity could not be demonstrated on a cardiac level. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Computational medical imaging and hemodynamics framework for functional analysis and assessment of cardiovascular structures.

PubMed

Wong, Kelvin K L; Wang, Defeng; Ko, Jacky K L; Mazumdar, Jagannath; Le, Thu-Thao; Ghista, Dhanjoo

2017-03-21

Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential. Some of these indicators constitute important cardiac functional parameters affecting the cardiovascular abnormalities. With the advancement of computer technology that facilitates high speed computational fluid dynamics, the realization of a support diagnostic platform of hemodynamics quantification and analysis can be achieved. This article reviews the state-of-the-art medical imaging and high fidelity multi-physics computational analyses that together enable reconstruction of cardiovascular structures and hemodynamic flow patterns within them, such as of the left ventricle (LV) and carotid bifurcations. The combined medical imaging and hemodynamic analysis enables us to study the mechanisms of cardiovascular disease-causing dysfunctions, such as how (1) cardiomyopathy causes left ventricular remodeling and loss of contractility leading to heart failure, and (2) modeling of LV construction and simulation of intra-LV hemodynamics can enable us to determine the optimum procedure of surgical ventriculation to restore its contractility and health This combined medical imaging and hemodynamics framework can potentially extend medical knowledge of cardiovascular defects and associated hemodynamic behavior and their surgical restoration, by means of an integrated medical image diagnostics and hemodynamic performance analysis framework.

Using a laser-Doppler flowmetry to measure pulsatile microcirculation on the kidney in rats

NASA Astrophysics Data System (ADS)

Jan, Ming-Yie; Chao, Pin-Tsun; Hsu, Tse-Lin; Wang, Yuh-Yin L.; Wang, Wei-Kung

2001-10-01

Although Laser Doppler flowmetery (LDF) been extensively used in measurement of microvascular blood flow of different tissues. However, due to some physiological vibrations, fast oscillations of the renal cortical flux (RCF) are hard to be measured. In the study, a commercial 3mW 780nm Laser Doppler flowmetery, with a single fiber and a de-vibration holder, was used to measure the pulsatile RCF in rats. Considering the fast response due to the heart rate of rats, the time constant (TC) was set to 0.05 second and thus the frequency response is up to 20Hz. Furthermore, a calibration standard and a static blood sample were also measured as the references without the pulsatile driving force. In order not to perturb the RCF with tiny momentum, the applying force that the fiber exerted on the renal surface was controlled below 100 dyne. To enhance the signal to noise ratio (SNR), an averaged periodogram was used to estimate the frequency components of the pulsatile microcirculation. It is found that the dominating fast oscillation of RCF is pulsatile and its harmonic components are directly correlated with those of the heartbeat (correlation coefficient =0.999, P<0.001, n=17). The result shows that, in the kidney, the pulsatile RCF is the dominating component of microcirculation oscillation and driven by the fast propagating blood pressure. This technique could be further utilized to analyze the pharmacological effect and hemodynamic parameters on renal function.

Understanding neural system dynamics through task modulation and measurement of functional MRI amplitude, latency, and width

PubMed Central

Bellgowan, P. S. F.; Saad, Z. S.; Bandettini, P. A.

2003-01-01

Estimates of hemodynamic amplitude, delay, and width were combined to investigate system dynamics involved in lexical decision making. Subjects performed a lexical decision task using word and nonword stimuli rotated 0°, 60°, or 120°. Averaged hemodynamic responses to repeated stimulation were fit to a Gamma-variate function convolved with a heavyside function of varying onset and duration to estimate each voxel's activation delay and width. Consistent with prolonged reaction times for the rotated stimuli and nonwords, the motor cortex showed delayed hemodynamic onset for both conditions. Language areas such as the lingual gyrus, middle temporal gyrus, fusiform gyrus, and precuneus all showed delayed hemodynamic onsets to rotated stimuli but not to nonword stimuli. The inferior frontal gyrus showed both increased onset latency for rotated stimuli and a wider hemodynamic response to nonwords, consistent with prolonged processing in this area during the lexical decision task. Phonological processing areas such as superior temporal and angular gyrus showed no delay or width difference for rotated stimuli. These results suggest that phonological routes but not semantic routes to the lexicon can proceed regardless of stimulus orientation. This study demonstrates the utility of estimating hemodynamic delay and width in addition to amplitude allowing for more quantitative measures of brain function such as mental chronometry. PMID:12552093

Left atrial strain predicts hemodynamic parameters in cardiovascular patients.

PubMed

Hewing, Bernd; Theres, Lena; Spethmann, Sebastian; Stangl, Karl; Dreger, Henryk; Knebel, Fabian

2017-08-01

We aimed to evaluate the predictive value of left atrial (LA) reservoir, conduit, and contractile function parameters as assessed by speckle tracking echocardiography (STE) for invasively measured hemodynamic parameters in a patient cohort with myocardial and valvular diseases. Sixty-nine patients undergoing invasive hemodynamic assessment were enrolled into the study. Invasive hemodynamic parameters were obtained by left and right heart catheterization. Transthoracic echocardiography assessment of LA reservoir, conduit, and contractile function was performed by STE. Forty-nine patients had sinus rhythm (SR) and 20 patients had permanent atrial fibrillation (AF). AF patients had significantly reduced LA reservoir function compared to SR patients. In patients with SR, LA reservoir, conduit, and contractile function inversely correlated with pulmonary capillary wedge pressure (PCWP), left ventricular end-diastolic pressure, and mean pulmonary artery pressure (PAP), and showed a moderate association with cardiac index. In AF patients, there were no significant correlations between LA reservoir function and invasively obtained hemodynamic parameters. In SR patients, LA contractile function with a cutoff value of 16.0% had the highest diagnostic accuracy (area under the curve, AUC: 0.895) to predict PCWP ≥18 mm Hg compared to the weaker diagnostic accuracy of average E/E' ratio with an AUC of 0.786 at a cutoff value of 14.3. In multivariate analysis, LA contractile function remained significantly associated with PCWP ≥18 mm Hg. In a cohort of patients with a broad spectrum of cardiovascular diseases LA strain shows a valuable prediction of hemodynamic parameters, specifically LV filling pressures, in the presence of SR. © 2017, Wiley Periodicals, Inc.

Acute Pretreatment with Chloroquine Attenuates Renal I/R Injury in Rats

PubMed Central

Todorovic, Zoran; Medic, Branislava; Basta-Jovanovic, Gordana; Radojevic Skodric, Sanja; Stojanovic, Radan; Rovcanin, Branislav; Prostran, Milica

2014-01-01

Background Acute kidney injury (AKI) still remains an unresolved problem in pharmacotherapy and renal inflammation is a major factor in its development. Chloroquine, a well-known antimalarial drug, posses pleitropic effects as well: antiinflammatory, anticoagulant and vascular actions. The effects of chloroquine on renal function may involve significant increase in urine flow rate, glomerular filtration rate and sodium excretion, as well as stimulation of nitric oxide synthase. However, its role in experimental models of renal I/R injury is unknown. We aimed to analyze the acute effects of a single-dose intravenous chloroquine administered at three different times in the experimental model of I/R injury in rat. Methods Rats were subjected to bilateral renal ischemia (45 min) followed by reperfusion with saline lasting 4 hours. Chloroquine was administered in doses of 0.3 mg/kg i.v. and 3 mg/kg i.v. 30 min before ischemia, 30 min before reperfusion and 5 min before reperfusion. Selected a hemodynamic, biochemical and morphological parameters were followed in the Sham-operated animals and rats subjected to I/R injury and pretreated with saline or chloroquine. Results Chloroquine (0.3 and 3 mg/kg, i.v.) protected the I/R injured kidney in an U-shaped manner. Both doses were protective regarding biochemical and histological markers of the I/R injury (serum urea, creatinine and fractional excretion of sodium, as well as total histological score, tubular necrosis score and KIM-1 staining score) (P<0.05 vs. corresponding controls, i.e. rats subjected to I/R injury and treated with saline only). The protective effects of the lower dose of chloroquine were more profound. Time-related differences between pretreatments were not observed (P>0.05, all). Conclusion Our study shows for the first time that a single dose of chloroquine (0.3 mg/kg i.v.) could afford significant protection of the injured rat kidney. PMID:24681567

Effects of fenoldopam on renal blood flow in hypertensive chronic kidney disease.

PubMed

Rovella, Valentina; Ferrannini, Michele; Tesauro, Manfredi; Marrone, Giulia; Busca, Andrea; Sorge, Roberto; Manca di Villahermosa, Simone; Casasco, Maurizio; Di Daniele, Nicola; Noce, Annalisa

2018-05-15

The synthetic drug fenoldopam mesylate (FM) may have a renoprotective role, and a "renal dose" of 0.1 µg/kg/min intravenous (IV) infusion of FM has been reported as able to increase renal blood flow without affecting systemic blood pressure. But conclusive data are still lacking. We aimed to investigate by color-Doppler ultrasonography the effects of IV administration of FM at this dosage in hypertensive chronic kidney disease (CKD) patients, and verify whether it may induce any systemic hemodynamic alteration. In 60 hypertensive CKD patients, we measured by duplex Doppler ultrasonography, at baseline and during infusion of 0.1 µg/kg/min of FM, the systolic and diastolic flow velocity (sampled at the renal hilum, intermediate section and origin of both renal arteries) and the intra-parenchymal renal resistive index (RRI) sampled on interlobular arteries of both kidneys. Patients were divided into four subgroups (I-IV) according to classification of National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-DOQI). Infusion of 0.1 µg/kg/min FM significantly decreased the RRI (0.73 ± 0.05 vs. 0.65 ± 0.06; p < 0.0001) and increased the systolic and diastolic flow velocities in all renal artery tracts examined. No single episode of systemic hypotension was observed. Very low-dose FM may significantly increase renal blood flow and exert a renal protective effect in hypertensive CKD patients. Infusion of FM at such low dosage appears also to be quite safe, even in CKD and hypertensive patients.

L-Arginine attenuates the ethylene glycol induced urolithiasis in ininephrectomized hypertensive rats: role of KIM-1, NGAL, and NOs.

PubMed

Kandhare, Amit D; Patil, Mithun V K; Bodhankar, Subhash L

2015-05-01

Ethylene glycol (EG) exposure caused formation of calcium oxalate crystal that led to renal failure, which is associated with higher prevalence of hypertension. L-Arginine is known to have an antioxidant and nephro-protective potential. To evaluate the effect of L-arginine against EG-induced urolithiasis in uninephrectomized hypertensive rats. Uninephrectomized male Wistar rats (180-200 g) were used to induce urinary calculi through oral administration of EG (0.75%) in distilled water. Rats were treated with either distilled water (10 mg/kg, p.o.) or telmisartan (10 mg/kg, p.o.) or Cystone (500 mg/kg, p.o.) or L-arginine (250, 500, and 1000 mg/kg, p.o.) for 28 days. Various hemodynamic, biochemical, molecular, and histological parameters were assessed in kidney and heart. Rats treated with L-arginine (500 and 1000 mg/kg) significantly restored altered relative organ weight, urine output, urine density, urinary pH, and water intake. EG-induced alterations in electrocardiographic (QRS interval, HR, and ST height) and hemodynamic (SBP, DBP, MABP, and LVEDP) abnormalities were significantly restored by L-arginine (500 and 1000 mg/kg) treatment. It also significantly restored alteration in serum and urine biochemical parameters induced by EG. The elevated oxido-nitrosative stress was also significantly decreased by L-arginine (500 and 1000 mg/kg) treatment. It also significantly down-regulated EG-induced up-regulated renal KIM-1, NGAL, eNOS, and iNOs mRNA expressions. Histological aberrations induced in the renal and cardiac tissues were also ameliorated by l-arginine treatment. L-Arginine exerts its nephro- and cardio-protective potential in EG-induced urolithiasis in uninephrectomized hypertensive rats via modulation of KIM-1, NGAL, eNOS, and iNOs mRNA expression.

Sex-specific effect of endothelin in the blood pressure response to acute angiotensin II in growth-restricted rats

PubMed Central

Intapad, Suttira; Ojeda, Norma B.; Varney, Elliott; Royals, Thomas P.; Alexander, Barbara T.

2015-01-01

The renal endothelin system contributes to sex differences in blood pressure with males demonstrating greater endothelin type-A receptor-mediated responses relative to females. Intrauterine growth restriction programs hypertension and enhanced renal sensitivity to acute angiotensin II in male growth-restricted rats. Endothelin is reported to work synergistically with angiotensin II. Thus, this study tested the hypothesis that endothelin augments the blood pressure response to acute angiotensin II in male growth-restricted rats. Systemic and renal hemodynamics were determined in response to acute angiotensin II (100 nanogram/kilogram/minute for 30 minutes) with and without the endothelin type-A receptor antagonist, ABT 627(10 nanogram/kilogram/minute for 30 minutes), in rats pretreated with enalapril (250 milligram/Liter for one week) to normalize the endogenous renin angiotensin system. Endothelin type-A receptor blockade reduced angiotensin II-mediated increases in blood pressure in male control and male growth-restricted rats. Endothelin type-A receptor blockade also abolished hyper-responsiveness to acute angiotensin II in male growth-restricted rats. Yet, blood pressure remained significantly elevated above baseline following endothelin type-A receptor blockade suggesting that factors in addition to endothelin contribute to the basic angiotensin II-induced pressor response in male rats. We also determined sex-specific effects of endothelin on acute angiotensin II-mediated hemodynamic responses. Endothelin type-A receptor blockade did not reduce acute angiotensin II-mediated increases in blood pressure in female control or growth-restricted rats, intact or ovariectomized. Thus, these data suggest that endothelin type-A receptor blockade contributes to hypersensitivity to acute angiotensin II in male growth-restricted rats and further supports the sex-specific effect of endothelin on blood pressure. PMID:26459423

Low-frequency oscillation amplitude elevation of prefrontal cerebral hemodynamics with driving duration during prolonged driving test

NASA Astrophysics Data System (ADS)

Deng, Zishan; Gao, Yuan; Li, Ting

2018-02-01

It has been observed that there is a low-frequency oscillation (LFO) around 0.1 Hz in cerebral hemodynamics related to brain activity. Since functional near-infrared spectroscopy (fNIRS) is a novel technique to monitor hemodynamic responses noninvasively, we applied it to detect LFOs of cerebral hemodynamic parameters, such as oxyhemoglobin and deoxyhemoglobin, during prolonged driving. We performed an experiment lasting for 7 hours and an experimental test was done every hour and 8 times altogether. 7 subjects were recruited and the data of 3 of them were analyzed. By means of Fourier transformation, the amplitude of the three parameters during each test at 0.1 Hz in frequency domain was extracted. The results showed an increasing trend in the 0.1 Hz amplitudes of the three hemodynamic parameters during 7 hours' simulated driving test. Our findings indicated the potential of LFOs of prefrontal cerebral hemodynamics in brain research and brain function evaluation.

A randomized, controlled, double-blind crossover study on the effects of 2-L infusions of 0.9% saline and plasma-lyte® 148 on renal blood flow velocity and renal cortical tissue perfusion in healthy volunteers.

PubMed

Chowdhury, Abeed H; Cox, Eleanor F; Francis, Susan T; Lobo, Dileep N

2012-07-01

We compared the effects of intravenous infusions of 0.9% saline ([Cl] 154 mmol/L) and Plasma-Lyte 148 ([Cl] 98 mmol/L, Baxter Healthcare) on renal blood flow velocity and perfusion in humans using magnetic resonance imaging (MRI). Animal experiments suggest that hyperchloremia resulting from 0.9% saline infusion may affect renal hemodynamics adversely, a phenomenon not studied in humans. Twelve healthy adult male subjects received 2-L intravenous infusions over 1 hour of 0.9% saline or Plasma-Lyte 148 in a randomized, double-blind manner. Crossover studies were performed 7 to 10 days apart. MRI scanning proceeded for 90 minutes after commencement of infusion to measure renal artery blood flow velocity and renal cortical perfusion. Blood was sampled and weight recorded hourly for 4 hours. Sustained hyperchloremia was seen with saline but not with Plasma-Lyte 148 (P < 0.0001), and fall in strong ion difference was greater with the former (P = 0.025). Blood volume changes were identical (P = 0.867), but there was greater expansion of the extravascular fluid volume after saline (P = 0.029). There was a significant reduction in mean renal artery flow velocity (P = 0.045) and renal cortical tissue perfusion (P = 0.008) from baseline after saline, but not after Plasma-Lyte 148. There was no difference in concentrations of urinary neutrophil gelatinase-associated lipocalin after the 2 infusions (P = 0.917). This is the first human study to demonstrate that intravenous infusion of 0.9% saline results in reductions in renal blood flow velocity and renal cortical tissue perfusion. This has implications for intravenous fluid therapy in perioperative and critically ill patients. NCT01087853.

Multicomponent Exercise Improves Physical Functioning but Not Cognition and Hemodynamic Parameters in Elderly Osteoarthritis Patients Regardless of Hypertension

PubMed Central

Gonçalvez, Ivan de Oliveira; Callado Sanches, Iris; Gonçalves, Leandro

2018-01-01

The present study aimed to investigate the impact of a 6-month multicomponent exercise program (MCEP) on physical function, cognition, and hemodynamic parameters of elderly normotensive (NTS) and hypertensive (HTS) osteoarthritis patients. A total of 99 elderly osteoarthritis patients (44 NTS and 55 HTS) were recruited and submitted to functional, cognitive, and hemodynamic evaluations before and after six months of a MCEP. The program of exercise was performed twice a week at moderate intensity. The physical exercises aggregated functional and walking exercises. Results indicate that 6 months of MCEP were able to improve one-leg stand and mobility (walking speeds) of osteoarthritis patients regardless of hypertension. On the other hand, cognitive and hemodynamic parameters were not altered after the MCEP. The findings of the present study demonstrate that 6 months of MCEP were able to improve the physical functioning (i.e., usual and maximal walking speed and balance) of osteoarthritis patients regardless of hypertensive condition. PMID:29721504

Renal denervation improves cardiac function in rats with chronic heart failure: Effects on expression of β-adrenoceptors

PubMed Central

Zheng, Hong; Liu, Xuefei; Sharma, Neeru M.

2016-01-01

Chronic activation of the sympathetic drive contributes to cardiac remodeling and dysfunction during chronic heart failure (HF). The present study was undertaken to assess whether renal denervation (RDN) would abrogate the sympathoexcitation in HF and ameliorate the adrenergic dysfunction and cardiac damage. Ligation of the left coronary artery was used to induce HF in Sprague-Dawley rats. Four weeks after surgery, RDN was performed, 1 wk before the final measurements. At the end of the protocol, cardiac function was assessed by measuring ventricular hemodynamics. Rats with HF had an average infarct area >30% of the left ventricle and left ventricular end-diastolic pressure (LVEDP) >20 mmHg. β1- and β2-adrenoceptor proteins in the left ventricle were reduced by 37 and 49%, respectively, in the rats with HF. RDN lowered elevated levels of urinary excretion of norepinephrine and brain natriuretic peptide levels in the hearts of rats with HF. RDN also decreased LVEDP to 10 mmHg and improved basal dP/dt to within the normal range in rats with HF. RDN blunted loss of β1-adrenoceptor (by 47%) and β2-adrenoceptor (by 100%) protein expression and improved isoproterenol (0.5 μg/kg)-induced increase in +dP/dt (by 71%) and −dP/dt (by 62%) in rats with HF. RDN also attenuated the increase in collagen 1 expression in the left ventricles of rats with HF. These findings demonstrate that RDN initiated in chronic HF condition improves cardiac function mediated by adrenergic agonist and blunts β-adrenoceptor expression loss, providing mechanistic insights for RDN-induced improvements in cardiac function in the HF condition. PMID:27288440

Measurements of coherent hemodynamics to enrich the physiological information provided by near-infrared spectroscopy (NIRS) and functional MRI

NASA Astrophysics Data System (ADS)

Sassaroli, Angelo; Tgavalekos, Kristen; Pham, Thao; Krishnamurthy, Nishanth; Fantini, Sergio

2018-02-01

Hemodynamic-based neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and near-infrared spectroscopy (NIRS) sense hemoglobin concentration in cerebral tissue. The local concentration of hemoglobin, which is differentiated into oxy- and deoxy-hemoglobin by NIRS, features spontaneous oscillations over time scales of 10-100 s in response to a number of local and systemic physiological processes. If one of such processes becomes the dominant source of cerebral hemodynamics, there is a high coherence between this process and the associated hemodynamics. In this work, we report a method to identify such conditions of coherent hemodynamics, which may be exploited to study and quantify microvasculature and microcirculation properties. We discuss how a critical value of significant coherence may depend on the specific data collection scheme (for example, the total acquisition time) and the nature of the hemodynamic data (in particular, oxy- and deoxy-hemoglobin concentrations measured with NIRS show an intrinsic level of correlation that must be taken into account). A frequency-resolved study of coherent hemodynamics is the basis for the new technique of coherent hemodynamics spectroscopy (CHS), which aims to provide measures of cerebral blood flow and cerebral autoregulation. While these concepts apply in principle to both fMRI and NIRS data, in this article we focus on NIRS data.

Acute renal failure associated with an accidental overdose of colchicine.

PubMed

Borrás-Blasco, J; Enriquez, R; Sirvent, A E; Amoros, F; Navarro-Ruiz, A; Reyes, A

2005-10-01

A 47-year-old man with a history of polyarticular gout was admitted to the nephrology service because of severe renal insufficiency (creatinine 6.25 mg/dl). Three days before admission he had a pain crisis in his knees and ankles and self-administered 20 x 1 mg granules of colchicine p.o. over a period of 4 - 5 hours together with six suppositories each containing 100 mg of indomethacin. The patient began vomiting within 24 hours, experienced diarrhea which persisted for three days and then came to the hospital. The patient reported oliguria during the preceding 24 hours. In hospital, attempts to correct water and electrolyte balance were initiated. The patient became stabilized hemo-dynamically, the diarrhea disappeared within 24 hours, diuresis resumed and the renal function progressively improved. Leukopenia and thrombopenia were diagnosed, the transaminases increased: AST = 79 U/l, ALT = 132 U/l on the eighth day after taking the colchicine. The serology for hepatitis A, B, C and HIV viruses was negative; the serology for CMV and VEB revealed a previous infection. After being discharged from hospital 11 days after admission, the patient presented with the following parameters: hematocrit 39%, leukocytes 5,920/microl (3 470 neutrophils), prothrombin time 13 seconds, urea 44 mg/dl, creatinine 1.29 mg/dl, AST 16 U/l and ALT 35 U/l. The patient mistakenly ingested 20 mg ofcolchicine p.o. (0.22 mg/kg). The intoxication was associated with gastroenterocolitis, dehydration and renal failure during the first three days after ingestion. The patient also developed leukopenia, thrombopenia and mild hepatocellular injury. Renal failure due to colchicine intoxication is due to various factors such as depletion of volume/hypotension, rhabdomyolysis and multiorgan failure. In this case, the hypovolemia was probably the fundamental cause of the acute renal insufficiency as demonstrated by the quick recovery after administering fluids. It is possible that indomethacin may have enhanced the toxic effect of colchicine on the kidneys and bone marrow. Some colchicine intoxications, as in this case, are caused by an error in interpreting the dose for treating an acute attack of gout. A way to prevent these errors would be to use a low-dose treatment protocol.

Gender Difference in Renal Blood Flow Response to Angiotensin II Administration after Ischemia/Reperfusion in Rats: The Role of AT2 Receptor.

PubMed

Maleki, Maryam; Nematbakhsh, Mehdi

2016-01-01

Background. Renal ischemia/reperfusion (I/R) is one of the major causes of kidney failure, and it may interact with renin angiotensin system while angiotensin II (Ang II) type 2 receptor (AT2R) expression is gender dependent. We examined the role of AT2R blockade on vascular response to Ang II after I/R in rats. Methods. Male and female rats were subjected to 30 min renal ischemia followed by reperfusion. Two groups of rats received either vehicle or AT2R antagonist, PD123319. Mean arterial pressure (MAP), and renal blood flow (RBF) responses were assessed during graded Ang II (100, 300, and 1000 ng/kg/min, i.v.) infusion at controlled renal perfusion pressure (RPP). Results. Vehicle or antagonist did not alter MAP, RPP, and RBF levels significantly; however, 30 min after reperfusion, RBF decreased insignificantly in female treated with PD123319 (P = 0.07). Ang II reduced RBF and increased renal vascular resistance (RVR) in a dose-related fashion (P dose < 0.0001), and PD123319 intensified the reduction of RBF response in female (P group < 0.005), but not in male rats. Conclusion. The impact of the AT2R on vascular responses to Ang II in renal I/R injury appears to be sexually dimorphic. PD123319 infusion promotes these hemodynamic responses in female more than in male rats.

Efficacy and safety of rectal ibuprofen for patent ductus arteriosus closure in very low birth weight preterm infants.

PubMed

Demir, Nihat; Peker, Erdal; Ece, İbrahim; Balahoroğlu, Ragıp; Tuncer, Oğuz

2017-09-01

To compare rectal ibuprofen with oral ibuprofen for the closure of hemodynamically significant patent ductus arteriosus (hsPDA) in very low birth weight (VLBW) preterm infants. In a prospective, randomized study, 72 VLBW infants who had hsPDA received either rectal or oral ibuprofen. The plasma concentration of ibuprofen and renal functions were determined in both groups by the high-performance liquid chromatography (HPLC) method and cystatin-C (cys-C), respectively. The hsPDA closure rate of the group that received rectal ibuprofen was similar to oral ibuprofen (86.1% versus 83.3%) after the first course of the treatment (p = 0.745). A statistically significant difference was identified between the mean plasma cys-C levels before and after treatment in both the rectal and oral ibuprofen groups (p = 0.004 and p< 0.001, respectively). The mean plasma ibuprofen concentration was similar in both groups after the first dose (rectal 44.06 ± 12.4; oral, 48.28 ± 22.8) and the third dose (rectal, 45.34 ± 24.3; oral, 48.94 ± 24.8) (p > 0.05 for all values). Rectal ibuprofen is as effective as oral ibuprofen for hsPDA closure in VLBW infants. The rise in the cys-C level with rectal and oral treatment shows that patients with borderline renal function should be evaluated and followed closely.

A New MRI-Based Model of Heart Function with Coupled Hemodynamics and Application to Normal and Diseased Canine Left Ventricles

PubMed Central

Choi, Young Joon; Constantino, Jason; Vedula, Vijay; Trayanova, Natalia; Mittal, Rajat

2015-01-01

A methodology for the simulation of heart function that combines an MRI-based model of cardiac electromechanics (CE) with a Navier–Stokes-based hemodynamics model is presented. The CE model consists of two coupled components that simulate the electrical and the mechanical functions of the heart. Accurate representations of ventricular geometry and fiber orientations are constructed from the structural magnetic resonance and the diffusion tensor MR images, respectively. The deformation of the ventricle obtained from the electromechanical model serves as input to the hemodynamics model in this one-way coupled approach via imposed kinematic wall velocity boundary conditions and at the same time, governs the blood flow into and out of the ventricular volume. The time-dependent endocardial surfaces are registered using a diffeomorphic mapping algorithm, while the intraventricular blood flow patterns are simulated using a sharp-interface immersed boundary method-based flow solver. The utility of the combined heart-function model is demonstrated by comparing the hemodynamic characteristics of a normal canine heart beating in sinus rhythm against that of the dyssynchronously beating failing heart. We also discuss the potential of coupled CE and hemodynamics models for various clinical applications. PMID:26442254

The Cardio-Renal Interrelationship.

PubMed

Boudoulas, Konstantinos Dean; Triposkiadis, Filippos; Parissis, John; Butler, Javed; Boudoulas, Harisios

The heart and the kidney are of utmost importance for the maintenance of cardiovascular (CV) homeostasis. In healthy subjects, hemodynamic changes in either organ may affect hemodynamics of the other organ. This interaction is fine-tuned by neurohumoral activity, including atrial natriuretic peptides, renin-angiotensin aldosterone system and sympathetic activity. Dysfunction or disease of one organ may initiate, accentuate, or precipitate dysfunction or disease state in the other organ, often leading to a vicious cycle. Further, the interaction between the heart and the kidney may occur in the setting of processes and diseases that may affect both organs simultaneously, such as advanced age, hypertension, diabetes mellitus, atherosclerosis, etc. In this regard, a stiff aorta that occurs with aging due to mechanical stress may independently initiate or precipitate dysfunction and disease in the heart and the kidney. All of these factors contribute to a high prevalence of coexistent CV and kidney disease, especially in the elderly. In advanced kidney disease, hemodynamic and neurohumoral homeostasis are lost, volume and pressure overload may coexist, and the elimination of certain pharmacologic agents may be substantially impaired. Thus, coexistence of CV and kidney disease complicates diagnosis, propagates pathophysiology, adversely affects prognosis, and hinders management. Copyright © 2016 Elsevier Inc. All rights reserved.

Renal oxygenation and hemodynamics in acute kidney injury and chronic kidney disease

PubMed Central

Singh, Prabhleen; Ricksten, Sven-Erik; Bragadottir, Gudrun; Redfors, Bengt; Nordquist, Lina

2013-01-01

Summary 1. Acute kidney injury (AKI) puts a major burden on health systems that may arise from multiple initiating insults, including ischemia-reperfusion injury, cardiovascular surgery, radio-contrast administration as well as sepsis. Similarly, the incidence and prevalence of chronic kidney disease (CKD) continues to increase with significant morbidity and mortality. Moreover, an increasing number of AKI patients survive to develop CKD and end-stage kidney disease (ESRD). 2. Although the mechanisms for development of AKI and progression of CKD remain poorly understood, initial impairment of oxygen balance is likely to constitute a common pathway, causing renal tissue hypoxia and ATP starvation that will in turn induce extracellular matrix production, collagen deposition and fibrosis. Thus, possible future strategies for one or both conditions may involve dopamine, loop-diuretics, inducible nitric oxide synthase inhibitors and atrial natriuretic peptide, substances that target kidney oxygen consumption and regulators of renal oxygenation such as nitric oxide and heme oxygenase-1. PMID:23360244

Anatomy and ultrasonography of the normal kidney in brown lemurs: Eulemur fulvus.

PubMed

Raharison, Fidiniaina; Mogicato, Giovanni; Sautet, Jean

2009-08-01

The purpose of this study is to describe the anatomy and obtain echographic measurements of normal kidneys in brown lemurs (Eulemur fulvus). The anatomical findings show that brown lemur kidneys are comparable to those of rats except for an elongated papilla. The kidneys of 16 (7 females and 9 males) lemurs were examined with two-dimensional and power Doppler ultrasonography under general anesthesia. Morphometrically, the left and right kidney surface areas are comparable (3.29 and 3.51 cm(2)). Kidney area has a significant linear correlation with body weight. Echo-Doppler findings show that the mean renal arterial blood flow speeds for the left and right kidneys are comparable (0.70 and 0.73 m/s). However, flow speed is higher in the male (0.79 m/s) than in the female (0.60 m/s). The renal arterial diameters are between 1.0 and 1.8 mm. The fact that anesthesia can have hemodynamic effects on renal vasculature should be taken into consideration when assessing these echographic results.

Successfully treated necrotizing fasciitis using extracorporeal life support combined with hemoadsorption device and continuous renal replacement therapy.

PubMed

Eid, Maroua; Fouquet, Olivier; Darreau, Cédric; Pierrot, Marc; Kouatchet, Achille; Mercat, Alain; Baufreton, Christophe

2018-03-01

Necrotizing fasciitis represents a life-threatening infectious condition that causes spreading necrotisis of superficial fascia and subcutaneous cellular tissues. We describe the case of a patient diagnosed with septic and toxic shocks leading to multiple organ failure successfully treated with a combination of extracorporeal life support, continuous renal replacement therapy, and a hemoadsorption device. A 41-year-old patient presented with necrotizing fasciitis and multi-organ failure. Initial extracorporeal life support therapy was implanted, compensating for systolic failure. Due to acute renal failure that persisted in time, continuous renal replacement therapy was added. Despite these treatments and as a last attempt to control the septic condition, a CytoSorb ® hemoadsorption device was installed in parallel to the extracorporeal life support circuit and two sessions were run. During the days following CytoSorb ® treatment, hemodynamic stabilization was observed, as well as normalization of lactic acidosis and blood parameters. This case describes the successful use of CytoSorb ® with continuous renal replacement therapy and extracorporeal life support in a combined way to overcome a critical phase of septic shock in a young adult patient. This combination of treatments turned out to be efficient for this patient in the context of necrotizing fasciitis.

An implantable blood pressure and flow transmitter.

NASA Technical Reports Server (NTRS)

Rader, R. D.; Meehan, J. P.; Henriksen, J. K. C.

1973-01-01

A miniature totally implantable FM/FM telemetry system has been developed to simultaneously measure blood pressure and blood flow, thus providing an appreciation of the hemodynamics of the circulation to the entire body or to a particular organ. Developed for work with animal subjects, the telemetry system's transmission time is controlled by an RF signal that permits an operating life of several months. Pressure is detected by a miniature intravascular transducer and flow is detected by an extravascular interferometric ultrasonic technique. Both pressure and flow are calibrated prior to implanting. The pressure calibration can be checked after the implanting by cannulation; flow calibration can be verified only at the end of the experiment by determining the voltage output from the implanted sensing system as a function of several measured flow rates. The utility of this device has been established by its use in investigating canine renal circulation during exercise, emotional encounters, administration of drugs, and application of accelerative forces.

Hemodynamics, renal function, plasma renin, and aldosterone in man after 5 to 14 days of bedrest

NASA Technical Reports Server (NTRS)

Melada, G. A.; Goldman, R. H.; Luetscher, J. A.; Zager, P. G.

1975-01-01

Continuous bedrest for 5 to 14 days had no significant effect on resting heart rate, blood pressure, or cardiac output in six normal men. Head-up tilt induced greater tachycardia in 5 of 6 patients after bed rest than in the control period. Propranolol diminished both tachycardia and the incidence of hypotension and faintness in upright posture. Plasma volume fell, extracellular fluid volume increased, and plasma renin activity was significantly elevated following bedrest. Unusually large increases in plasma renin followed head-up tilt or administration of isoproterenol during bedrest and after resuming normal activity. During bedrest, plasma aldosterone was often increased in the early morning. It is concluded that after bedrest, upright posture evokes strong beta-adrenergic activity as well as exaggerated metabolic and circulatory responses which can be reduced or abolished by the beta-adrenergic blocker, propranolol.

Investigation of the cerebral hemodynamic response function in single blood vessels by functional photoacoustic microscopy

PubMed Central

Liao, Lun-De; Lin, Chin-Teng; Shih, Yen-Yu I.; Lai, Hsin-Yi; Zhao, Wan-Ting; Duong, Timothy Q.; Chang, Jyh-Yeong; Chen, You-Yin

2012-01-01

Abstract. The specificity of the hemodynamic response function (HRF) is determined spatially by the vascular architecture and temporally by the evolution of hemodynamic changes. Here, we used functional photoacoustic microscopy (fPAM) to investigate single cerebral blood vessels of rats after left forepaw stimulation. In this system, we analyzed the spatiotemporal evolution of the HRFs of the total hemoglobin concentration (HbT), cerebral blood volume (CBV), and hemoglobin oxygen saturation (SO2). Changes in specific cerebral vessels corresponding to various electrical stimulation intensities and durations were bilaterally imaged with 36×65-μm2 spatial resolution. Stimulation intensities of 1, 2, 6, and 10 mA were applied for periods of 5 or 15 s. Our results show that the relative functional changes in HbT, CBV, and SO2 are highly dependent not only on the intensity of the stimulation, but also on its duration. Additionally, the duration of the stimulation has a strong influence on the spatiotemporal characteristics of the HRF as shorter stimuli elicit responses only in the local vasculature (smaller arterioles), whereas longer stimuli lead to greater vascular supply and drainage. This study suggests that the current fPAM system is reliable for studying relative cerebral hemodynamic changes, as well as for offering new insights into the dynamics of functional cerebral hemodynamic changes in small animals. PMID:22734740

Isosorbide 5 mononitrate administration increases nitric oxide blood levels and reduces proteinuria in IgA glomerulonephritis patients with abnormal urinary endothelin/cyclic GMP ratio.

PubMed

Roccatello, D; Mengozzi, G; Ferro, M; Cesano, G; Polloni, R; Mosso, R; Bonetti, G; Inconis, T; Paradisi, L; Sena, L M

1995-09-01

An endothelin urinary hyperexcretion, which is not counterbalanced by an adequate increase in cGMP biosynthesis, was previously detected in some patients with IgA Nephropathy (IgAN). Since this imbalance might potentiate local ET1-mediated hemodynamics effects, 9 IgAN patients with an increased (> or = 0.1) urinary ET1/cGMP ratio (group 1) and 5 IgAN patients with comparable renal function and reduced ET1/cGMP ratio (group 2) were given standard doses of isosorbide 5 mononitrate (as a nitric oxide source). Blood nitric oxide (NO) levels, as detected by electron paramagnetic resonance, significantly increased after isosorbide administration (p < 0.01) and decreased after drug discontinuation in both groups. Nitric oxide levels were significantly related with those of the effective renal plasma flow (p < 0.02), but not with the glomerular filtration rate. Proteinuria levels significantly decreased after drug administration (p < 0.009) in group 1 and returned to baseline levels thereafter, except two cases showing persisting low levels. Values of filtration fraction in the same group decreased after iso5M administration (p < 0.02 compared to basal levels). These results may possibly be related to the counterbalancing effects of nitric oxide on endothelin-mediated mesangial contraction.

Comparison of two aquaretic drugs (niravoline and OPC-31260) in cirrhotic rats with ascites and water retention.

PubMed

Bosch-Marcé, M; Poo, J L; Jiménez, W; Bordas, N; Leivas, A; Morales-Ruiz, M; Muñoz, R M; Pérez, M; Arroyo, V; Rivera, F; Rodés, J

1999-04-01

kappa-Opioid receptor agonists (niravoline) or nonpeptide antidiuretic hormone (ADH) V2 receptor antagonists (OPC-31260) possess aquaretic activity in cirrhosis; however, there is no information concerning the effects induced by the chronic administration of these drugs under this condition. To compare the renal and hormonal effects induced by the long-term oral administration of niravoline, OPC-31260, or vehicle, urine volume, urinary osmolality, sodium excretion, and urinary excretion of aldosterone (ALD) and ADH were measured in basal conditions and for 10 days after the daily oral administration of niravoline, OPC-31260, or vehicle to cirrhotic rats with ascites and water retention. Creatinine clearance, serum osmolality, ADH mRNA expression, and systemic hemodynamics were also measured at the end of the study. Niravoline increased water excretion, peripheral resistance, serum osmolality, and sodium excretion and reduced creatinine clearance, ALD and ADH excretion, and mRNA expression of ADH. OPC-31260 also increased water metabolism and sodium excretion and reduced urinary ALD, although the aquaretic effect was only evident during the first 2 days, and no effects on serum osmolality, renal filtration, and systemic hemodynamics were observed. Therefore, both agents have aquaretic efficacy, but the beneficial therapeutic effects of the long-term oral administration of niravoline are more consistent than those of OPC-31260 in cirrhotic rats with ascites and water retention.

Extracorporeal life support in lung and heart-lung transplantation for pulmonary hypertension in adults.

PubMed

Kortchinsky, Talna; Mussot, Sacha; Rezaiguia, Saïda; Artiguenave, Margaux; Fadel, Elie; Stephan, François

2016-09-01

After bilateral lung and heart-lung transplantation in adults with pulmonary hypertension, hemodynamic and oxygenation deficiencies are life-threatening complications that are increasingly managed with extracorporeal life support (ECLS). The primary aim of this retrospective study was to assess 30-day and 1-year survival rates in patients managed with vs without post-operative venoarterial ECLS in 2008-2013. The secondary endpoints were the occurrence rates of nosocomial infection, bleeding, and acute renal failure. Of the 93 patients with pulmonary hypertension who received heart-lung (n=29) or bilateral lung (n=64) transplants, 28 (30%) required ECLS a median of 0 [0-6] hours after surgery completion and for a median of 3.0 [2.0-8.5] days. Compared to ECLS patients, controls had higher survival at 30 days (95.0% vs 78.5%; P=.02) and 1 year (83% vs 64%; P=.005), fewer nosocomial infections (48% vs 79%; P=.0006), and fewer bleeding events (17% vs 43%; P=.008). The need for renal replacement therapy was not different between groups (11% vs 17%; P=.54). Venoarterial ECLS is effective in treating pulmonary graft dysfunction with hemodynamic failure after heart-lung or bilateral lung. However, ECLS use was associated with higher rates of infection and bleeding. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Fluid therapy for septic shock resuscitation: which fluid should be used?

PubMed

Corrêa, Thiago Domingos; Rocha, Leonardo Lima; Pessoa, Camila Menezes Souza; Silva, Eliézer; de Assuncao, Murillo Santucci Cesar

2015-01-01

Early resuscitation of septic shock patients reduces the sepsis-related morbidity and mortality. The main goals of septic shock resuscitation include volemic expansion, maintenance of adequate tissue perfusion and oxygen delivery, guided by central venous pressure, mean arterial pressure, mixed or central venous oxygen saturation and arterial lactate levels. An aggressive fluid resuscitation, possibly in association with vasopressors, inotropes and red blood cell concentrate transfusion may be necessary to achieve those hemodynamic goals. Nonetheless, even though fluid administration is one of the most common interventions offered to critically ill patients, the most appropriate type of fluid to be used remains controversial. According to recently published clinical trials, crystalloid solutions seem to be the most appropriate type of fluids for initial resuscitation of septic shock patients. Balanced crystalloids have theoretical advantages over the classic solutions, but there is not enough evidence to indicate it as first-line treatment. Additionally, when large amounts of fluids are necessary to restore the hemodynamic stability, albumin solutions may be a safe and effective alternative. Hydroxyethyl starches solutions must be avoided in septic patients due to the increased risk of acute renal failure, increased need for renal replacement therapy and increased mortality. Our objective was to present a narrative review of the literature regarding the major types of fluids and their main drawbacks in the initial resuscitation of the septic shock patients.

Hemodynamic Response Alteration As a Function of Task Complexity and Expertise—An fNIRS Study in Jugglers

PubMed Central

Carius, Daniel; Andrä, Christian; Clauß, Martina; Ragert, Patrick; Bunk, Michael; Mehnert, Jan

2016-01-01

Detailed knowledge about online brain processing during the execution of complex motor tasks with a high motion range still remains elusive. The aim of the present study was to investigate the hemodynamic responses within sensorimotor networks as well as in visual motion area during the execution of a complex visuomotor task such as juggling. More specifically, we were interested in how far the hemodynamic response as measured with functional near infrared spectroscopy (fNIRS) adapts as a function of task complexity and the level of the juggling expertise. We asked expert jugglers to perform different juggling tasks with different levels of complexity such as a 2-ball juggling, 3- and 5-ball juggling cascades. We here demonstrate that expert jugglers show an altered neurovascular response with increasing task complexity, since a 5-ball juggling cascade showed enhanced hemodynamic responses for oxygenated hemoglobin as compared to less complex tasks such as a 3- or 2-ball juggling pattern. Moreover, correlations between the hemodynamic response and the level of the juggling expertise during the 5-ball juggling cascade, acquired by cinematographic video analysis, revealed only a non-significant trend in primary motor cortex, indicating that a higher level of expertise might be associated with lower hemodynamic responses. PMID:27064925

Effects of levosimendan on glomerular filtration rate, renal blood flow, and renal oxygenation after cardiac surgery with cardiopulmonary bypass: a randomized placebo-controlled study.

PubMed

Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2013-10-01

Acute kidney injury develops in a large proportion of patients after cardiac surgery because of the low cardiac output syndrome. The inodilator levosimendan increases cardiac output after cardiac surgery with cardiopulmonary bypass, but a detailed analysis of its effects on renal perfusion, glomerular filtration, and renal oxygenation in this group of patients is lacking. We therefore evaluated the effects of levosimendan on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen demand/supply relationship, i.e., renal oxygen extraction, early after cardiac surgery with cardiopulmonary bypass. Prospective, placebo-controlled, and randomized trial. Cardiothoracic ICU of a tertiary center. Postcardiac surgery patients (n=30). The patients were randomized to receive levosimendan, 0.1 µg/kg/min after a loading dose of 12 µg/kg (n=15), or placebo (n=15). The experimental procedure started 4-6 hours after surgery in the ICU during propofol sedation and mechanical ventilation. Systemic hemodynamic were evaluated by a pulmonary artery thermodilution catheter. Renal blood flow and glomerular filtration rate were measured by the renal vein retrograde thermodilution technique and by renal extraction of Cr-EDTA, respectively. Central venous pressure was kept constant by colloid/crystalloid infusion. Compared to placebo, levosimendan increased cardiac index (22%), stroke volume index (15%), and heart rate (7%) and decreased systemic vascular resistance index (21%), whereas mean arterial pressure was not affected. Levosimendan induced significant increases in renal blood flow (12%, p<0.05) and glomerular filtration rate (21%, p<0.05), decreased renal vascular resistance (18%, p<0.05) but caused no significant changes in filtration fraction, renal oxygen consumption, or renal oxygen extraction, compared to placebo. After cardiac surgery with cardiopulmonary bypass, levosimendan induces a vasodilation, preferentially of preglomerular resistance vessels, increasing both renal blood flow and glomerular filtration rate without jeopardizing renal oxygenation. Due to its pharmacodynamic profile, levosimendan might be an interesting alternative for treatment of postoperative heart failure complicated by acute kidney injury in postcardiac surgery patients.

[Diuretics in heart failure and Karl Popper's turkey].

PubMed

Cice, Gennaro

2015-12-01

Heart failure and renal failure often coexist in the same patient. This condition is commonly referred to as cardiorenal syndrome. When this occurs, patient survival worsens significantly with increasing degree of renal dysfunction. Management of this complex patient poses treatment challenges because of unstable hemodynamics (the problem is to reduce congestion without affecting organ perfusion) and very high mid-term in-hospital mortality. Congestion is a typical feature of this syndrome, and use of diuretics is mandatory. Loop diuretics should be administered first. However, poor attention to pharmacodynamic and pharmacokinetic properties of loop diuretics may contribute to the development of diuretic resistance leading to iatrogenic hyponatremia. Accordingly, emphasis is given to the importance of sequential nephron blockade to reduce the number of non-responder patients to diuretics and to recognize a possible role for acquaretics.

Renal transplantation induces mitochondrial uncoupling, increased kidney oxygen consumption, and decreased kidney oxygen tension.

PubMed

Papazova, Diana A; Friederich-Persson, Malou; Joles, Jaap A; Verhaar, Marianne C

2015-01-01

Hypoxia is an acknowledged pathway to renal injury and ischemia-reperfusion (I/R) and is known to reduce renal oxygen tension (Po2). We hypothesized that renal I/R increases oxidative damage and induces mitochondrial uncoupling, resulting in increased oxygen consumption and hence kidney hypoxia. Lewis rats underwent syngenic renal transplantation (TX) and contralateral nephrectomy. Controls were uninephrectomized (1K-CON) or left untreated (2K-CON). After 7 days, urinary excretion of protein and thiobarbituric acid-reactive substances were measured, and after 14 days glomerular filtration rate (GFR), renal blood flow, whole kidney Qo2, cortical Po2, kidney cortex mitochondrial uncoupling, renal oxidative damage, and tubulointerstitial injury were assessed. TX, compared with 1K-CON, resulted in mitochondrial uncoupling mediated via uncoupling protein-2 (16 ± 3.3 vs. 0.9 ± 0.4 pmol O2 · s(-1)· mg protein(-1), P < 0.05) and increased whole kidney Qo2 (55 ± 16 vs. 33 ± 10 μmol O2/min, P < 0.05). Corticomedullary Po2 was lower in TX compared with 1K-CON (30 ± 13 vs. 47 ± 4 μM, P < 0.05) whereas no significant difference was observed between 2K-CON and 1K-CON rats. Proteinuria, oxidative damage, and the tubulointerstitial injury score were not significantly different in 1K-CON and TX. Treatment of donors for 5 days with mito-TEMPO reduced mitochondrial uncoupling but did not affect renal hemodynamics, Qo2, Po2, or injury. Collectively, our results demonstrate increased mitochondrial uncoupling as an early event after experimental renal transplantation associated with increased oxygen consumption and kidney hypoxia in the absence of increases in markers of damage. Copyright © 2015 the American Physiological Society.

The impact of galectin-3 inhibition on aldosterone-induced cardiac and renal injuries.

PubMed

Calvier, Laurent; Martinez-Martinez, Ernesto; Miana, Maria; Cachofeiro, Victoria; Rousseau, Elodie; Sádaba, J Rafael; Zannad, Faiez; Rossignol, Patrick; López-Andrés, Natalia

2015-01-01

This study investigated whether galectin (Gal)-3 inhibition could block aldosterone-induced cardiac and renal fibrosis and improve cardiorenal dysfunction. Aldosterone is involved in cardiac and renal fibrosis that is associated with the development of cardiorenal injury. However, the mechanisms of these interactions remain unclear. Gal-3, a β-galactoside-binding lectin, is increased in heart failure and kidney injury. Rats were treated with aldosterone-salt combined with spironolactone (a mineralocorticoid receptor antagonist) or modified citrus pectin (a Gal-3 inhibitor), for 3 weeks. Wild-type and Gal-3 knockout mice were treated with aldosterone for 3 weeks. Hemodynamic, cardiac, and renal parameters were analyzed. Hypertensive aldosterone-salt-treated rats presented cardiac and renal hypertrophy (at morphometric, cellular, and molecular levels) and dysfunction. Cardiac and renal expressions of Gal-3 as well as levels of molecular markers attesting fibrosis were also augmented by aldosterone-salt treatment. Spironolactone or modified citrus pectin treatment reversed all of these effects. In wild-type mice, aldosterone did not alter blood pressure levels but increased cardiac and renal Gal-3 expression, fibrosis, and renal epithelial-mesenchymal transition. Gal-3 knockout mice were resistant to aldosterone effects. In experimental hyperaldosteronism, the increase in Gal-3 expression was associated with cardiac and renal fibrosis and dysfunction but was prevented by pharmacological inhibition (modified citrus pectin) or genetic disruption of Gal-3. These data suggest a key role for Gal-3 in cardiorenal remodeling and dysfunction induced by aldosterone. Gal-3 could be used as a new biotarget for specific pharmacological interventions. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Chronic nephropathies of cocaine and heroin abuse: a critical review.

PubMed

Jaffe, Jared A; Kimmel, Paul L

2006-07-01

Renal disease in cocaine and heroin users is associated with the nephrotic syndrome, acute glomerulonephritis, amyloidosis, interstitial nephritis, and rhabdomyolysis. The pathophysiologic basis of cocaine-related renal injury involves renal hemodynamic changes, glomerular matrix synthesis and degradation, and oxidative stress and induction of renal atherogenesis. Heroin is the most commonly abused opiate in the United States. Previous studies identified a spectrum of renal diseases in heroin users. The predominant renal lesion in black heroin users is focal segmental glomerulosclerosis and in white heroin users is membranoproliferative glomerulonephritis. Although the prevalence of heroin use in the United States has increased, the incidence of "heroin nephropathy" has declined. Because reports of heroin nephropathy predated the surveillance of hepatitis C virus and HIV, the varied findings might be related to the spectrum of viral illnesses that are encountered in injection drug users. Socioeconomic conditions, cultural and behavioral practices, or differences in genetic susceptibilities may be more associated with the development of nephropathy in heroin users than the drug's pharmacologic properties. Administration of cocaine in animal models results in nonspecific glomerular, interstitial, and tubular cell lesions, but there is no animal model of heroin-associated renal disease. The heterogeneity of responses that are associated with heroin is not consistent with a single or simple notion of nephropathogenesis. There are no well-designed, prospective, epidemiologic studies to assess the incidence and the prevalence of renal disease in populations of opiate users and to establish the validity of a syndrome such as heroin nephropathy. It is concluded although there is a paucity of evidence to support a heroin-associated nephropathy, the evidence from in vitro cellular and animal studies to support the existence of cocaine-induced renal changes is more convincing.

Evolution from electrophysiologic to hemodynamic monitoring: the story of left atrial and pulmonary artery pressure monitors.

PubMed

Mooney, Deirdre M; Fung, Erik; Doshi, Rahul N; Shavelle, David M

2015-01-01

Heart failure (HF) is a costly, challenging and highly prevalent medical condition. Hospitalization for acute decompensation is associated with high morbidity and mortality. Despite application of evidence-based medical therapies and technologies, HF remains a formidable challenge for virtually all healthcare systems. Repeat hospitalizations for acute decompensated HF (ADHF) can have major financial impact on institutions and resources. Early and accurate identification of impending ADHF is of paramount importance yet there is limited high quality evidence or infrastructure to guide management in the outpatient setting. Historically, ADHF was identified by physical exam findings or invasive hemodynamic monitoring during a hospital admission; however, advances in medical microelectronics and the advent of device-based diagnostics have enabled long-term ambulatory monitoring of HF patients in the outpatient setting. These monitors have evolved from piggybacking on cardiac implantable electrophysiologic devices to standalone implantable hemodynamic monitors that transduce left atrial or pulmonary artery pressures as surrogate measures of left ventricular filling pressure. As technology evolves, devices will likely continue to miniaturize while their capabilities grow. An important, persistent challenge that remains is developing systems to translate the large volumes of real-time data, particularly data trends, into actionable information that leads to appropriate, safe and timely interventions without overwhelming outpatient cardiology and general medical practices. Future directions for implantable hemodynamic monitors beyond their utility in heart failure may include management of other major chronic diseases such as pulmonary hypertension, end stage renal disease and portal hypertension.

A Review of Central Venous Pressure and Its Reliability as a Hemodynamic Monitoring Tool in Veterinary Medicine.

PubMed

Hutchinson, Kristen M; Shaw, Scott P

2016-09-01

To review the current literature regarding central venous pressure (CVP) in veterinary patients pertaining to placement (of central line), measurement, interpretation, use in veterinary medicine, limitations, and controversies in human medicine. CVP use in human medicine is a widely debated topic, as numerous sources have shown poor correlation of CVP measurements to the volume status of a patient. Owing to the ease of placement and monitoring in veterinary medicine, CVP remains a widely used modality for evaluating the hemodynamic status of a patient. A thorough evaluation of the veterinary and human literature should be performed to evaluate the role of CVP measurements in assessing volume status in veterinary patients. Veterinary patients that benefit from accurate CVP readings include those suffering from hypovolemic or septic shock, heart disease, or renal disease or all of these. Other patients that may benefit from CVP monitoring include high-risk anesthetic patients undergoing major surgery, trending of fluid volume status in critically ill patients, patients with continued shock, and patients that require rapid or large amounts of fluids. The goal of CVP use is to better understand a patient's intravascular volume status, which would allow early goal-directed therapy. CVP would most likely continue to play an important role in the hemodynamic monitoring of the critically ill veterinary patient; however, when available, cardiac output methods should be considered the first choice for hemodynamic monitoring. Copyright © 2016 Elsevier Inc. All rights reserved.

Milrinone, dobutamine or epinephrine use in asphyxiated newborn pigs resuscitated with 100% oxygen.

PubMed

Joynt, Chloë; Bigam, David L; Charrois, Gregory; Jewell, Laurence D; Korbutt, Gregory; Cheung, Po-Yin

2010-06-01

After resuscitation, asphyxiated neonates often develop poor cardiac function with hypotension, pulmonary hypertension and multiorgan ischemia. In a swine model of neonatal hypoxia-reoxygenation, effects of epinephrine, dobutamine and milrinone on systemic, pulmonary and regional hemodynamics and oxygen transport were compared. Controlled, block-randomized study. University research laboratory. Mixed breed piglets (1-3 days, 1.5-2.3 kg). In acutely instrumented piglets, normocapnic alveolar hypoxia (10-15% oxygen) was induced for 2 h followed by reoxygenation with 100% oxygen (1 h) then 21% oxygen (3 h). At 2 h of reoxygenation, after volume loading (Ringer's lactate 10 ml/kg), either saline (placebo), epinephrine (0.5 microg/kg/min), dobutamine (20 microg/kg/min) or milrinone (0.75 microg/kg/min) were infused for 2 h in a blinded, block-randomized fashion (n = 6/group). All medications similarly improved cardiac output, stroke volume and systemic oxygen delivery (vs. placebo-controls, p < 0.05). Epinephrine and dobutamine significantly increased, while milrinone maintained, mean arterial pressure over pretreatment values while placebo-treated piglets developed hypotension and shock. The mean arterial to pulmonary arterial pressures ratio was not different among groups. All medications significantly increased carotid and intestinal, but not renal, arterial blood flows and oxygen delivery, whereas milrinone caused lower renal vascular resistance than epinephrine and dobutamine-treated groups. Plasma troponin I, plasma and myocardial lactate levels, and histologic ischemic features were not different among groups. In newborn piglets with hypoxia-reoxygenation, epinephrine, dobutamine and milrinone are effective inotropes to improve cardiac output, carotid and intestinal perfusion, without aggravating pulmonary hypertension. Milrinone may also improve renal perfusion.

Nitric oxide system and diabetic nephropathy

PubMed Central

2014-01-01

About 30% of patients with type 2 diabetes mellitus develop clinically overt nephropathy. Hyperglycemia is necessary, but not sufficient, to cause the renal damage that leads to kidney failure. Diabetic nephropathy (DN) is a multifactorial disorder that results from interaction between environmental and genetic factors. In the present article we will review the role of the nitric oxide synthase (NOS) in the pathogenesis of DN. Nitric oxide (NO) is a short-lived gaseous lipophilic molecule produced in almost all tissues, and it has three distinct genes that encode three NOS isoforms: neuronal (nNOS), inducible (iNOS) and endothelial (eNOS). The correct function of the endothelium depends on NO, participating in hemostasis control, vascular tone regulation, proliferation of vascular smooth muscle cells and blood pressure homeostasis, among other features. In the kidney, NO plays many different roles, including control of renal and glomerular hemodynamics. The net effect of NO in the kidney is to promote natriuresis and diuresis, along with renal adaptation to dietary salt intake. The eNOS gene has been considered a potential candidate gene for DN susceptibility. Three polymorphisms have been extensively researched: G894T missense mutation (rs1799983), a 27-bp repeat in intron 4, and the T786C single nucleotide polymorphism (SNP) in the promoter (rs2070744). However, the potential link between eNOS gene variants and the induction and progression of DN yielded contradictory results in the literature. In conclusion, NOS seems to be involve in the development and progression of DN. Despite the discrepant results of many studies, the eNOS gene is also a good candidate gene for DN. PMID:24520999

Rapid Cerebral Hemodynamic Modulation during Set Shifting: Evidence of Time-Locked Associations with Cognitive Control in Females

ERIC Educational Resources Information Center

Schuepbach, Daniel; Huizinga, Mariette; Duschek, Stefan; Grimm, Simone; Boeker, Heinz; Hell, Daniel

2009-01-01

Set shifting provokes specific alterations of cerebral hemodynamics in basal cerebral arteries. However, no gender differences have been reported. In the following functional transcranial Doppler study, we introduced cerebral hemodynamic modulation to the aspects of set shifting during Wisconsin Card Sorting Test (WCST). Twenty-one subjects…

Correlation between differential renal function estimation using CT-based functional renal parenchymal volume and (99m)Tc - DTPA renal scan.

PubMed

Sarma, Debanga; Barua, Sasanka K; Rajeev, T P; Baruah, Saumar J

2012-10-01

Nuclear renal scan is currently the gold standard imaging study to determine differential renal function. We propose helical CT as single modality for both the anatomical and functional evaluation of kidney with impaired function. In the present study renal parenchymal volume is measured and percent total renal volume is used as a surrogate marker for differential renal function. The objective of this study is to correlate between differential renal function estimation using CT-based renal parenchymal volume measurement with differential renal function estimation using (99m)TC - DTPA renal scan. Twenty-one patients with unilateral obstructive uropathy were enrolled in this prospective comparative study. They were subjected to (99m)Tc - DTPA renal scan and 64 slice helical CT scan which estimates the renal volume depending on the reconstruction of arterial phase images followed by volume rendering and percent renal volume was calculated. Percent renal volume was correlated with percent renal function, as determined by nuclear renal scan using Pearson coefficient. RESULTS AND OBSERVATION: A strong correlation is observed between percent renal volume and percent renal function in obstructed units (r = 0.828, P < 0.001) as well as in nonobstructed units (r = 0.827, P < 0.001). There is a strong correlation between percent renal volume determined by CT scan and percent renal function determined by (99m)TC - DTPA renal scan both in obstructed and in normal units. CT-based percent renal volume can be used as a single radiological tests for both functional and anatomical assessment of impaired renal units.

Methods for measuring right ventricular function and hemodynamic coupling with the pulmonary vasculature.

PubMed

Bellofiore, Alessandro; Chesler, Naomi C

2013-07-01

The right ventricle (RV) is a pulsatile pump, the efficiency of which depends on proper hemodynamic coupling with the compliant pulmonary circulation. The RV and pulmonary circulation exhibit structural and functional differences with the more extensively investigated left ventricle (LV) and systemic circulation. In light of these differences, metrics of LV function and efficiency of coupling to the systemic circulation cannot be used without modification to characterize RV function and efficiency of coupling to the pulmonary circulation. In this article, we review RV physiology and mechanics, established and novel methods for measuring RV function and hemodynamic coupling, and findings from application of these methods to RV function and coupling changes with pulmonary hypertension. We especially focus on non-invasive measurements, as these may represent the future for clinical monitoring of disease progression and the effect of drug therapies.

Echocardiographic assessment of hemodynamic changes produced by two methods of inducing fluid deficit in dogs.

PubMed

Fine, D M; Durham, H E; Rossi, N F; Spier, A W; Selting, K; Rubin, L J

2010-01-01

Hydration status is important to the cardiovascular system because of its effects on preload. Decreased preload can alter echocardiographic measurements of systolic and diastolic function, potentially confounding interpretation of results. Mild fluid deficits are associated with measurable echocardiographic changes that are validated by physical and biochemical markers of decreased intravascular volume. Twenty-five healthy staff/student-owned dogs with no evidence of cardiac or renal disease. Prospective, interventional laboratory study. Dogs were randomly assigned to water deprivation (WD) alone for 8 hours (n = 13) or to furosemide treatment (FTx, 2.5mg/kg IV) followed by WD for 8 hours (n = 12). Echocardiograms, biochemical sampling, and physical parameters were measured at baseline, and after 4 and 8 hours. Both protocols induced fluid deficit as indicated by significant (P < .00001) decreases in weight at 4 hours (WD, 1.1%; FTx, 3.7%) and 8 hours (WD, 2.7%; FTx, 4.5%). Furosemide significantly decreased left ventricular end-diastolic volume (54.3 +/- 19.3-42.1 +/- 17.3 mL, P < .0001), cardiac index (4.2 +/- 1.1-2.9 +/- 0.9 L/min/M2, P < .0001), and mitral valve E wave velocity (0.79 +/- 0.2-0.66 +/- 0.2 m/s, P = .0004). These changes were accompanied by significant increases in blood urea nitrogen concentration (13.8 +/- 2.6-14.8 +/- 2.7 mg/dL, P = .04), vasopressin concentration (1.4 +/- 1.2-3.3 +/- 1.9 pg/mL, P = .045), and PCV (49.8 +/- 4.5-53.2 +/- 6.5%, P = .006). Effects of water deprivation alone were similar, but less pronounced. Mild fluid deficits have measurable hemodynamic effects in dogs. Hydration status should be considered when evaluating cardiac function by echocardiogram.

Functions of the Renal Nerves.

ERIC Educational Resources Information Center

Koepke, John P.; DiBona, Gerald F.

1985-01-01

Discusses renal neuroanatomy, renal vasculature, renal tubules, renin secretion, renorenal reflexes, and hypertension as related to renal nerve functions. Indicates that high intensitites of renal nerve stimulation have produced alterations in several renal functions. (A chart with various stimulations and resultant renal functions and 10-item,…

The association between cognitive deficits and prefrontal hemodynamic responses during performance of working memory task in patients with schizophrenia.

PubMed

Pu, Shenghong; Nakagome, Kazuyuki; Itakura, Masashi; Iwata, Masaaki; Nagata, Izumi; Kaneko, Koichi

2016-04-01

Schizophrenia-associated cognitive deficits are resistant to treatment and thus pose a lifelong burden. The Brief Assessment of Cognition in Schizophrenia (BACS) provides reliable and valid assessments across cognitive domains. However, because the prefrontal functional abnormalities specifically associated with the level of cognitive deficits in schizophrenia have not been examined, we explored this relationship. Patients with schizophrenia (N=87) and matched healthy controls (N=50) participated in the study. Using near-infrared spectroscopy (NIRS), we measured the hemodynamic responses in the prefrontal and superior temporal cortical surface areas during a working memory task. Correlation analyses revealed a relationship between the hemodynamics and the BACS composite and domain scores. Hemodynamic responses of the left dorsolateral prefrontal cortex (DLPFC) and left frontopolar cortex (FPC) in the higher-level-of-cognitive-function schizophrenia group were weaker than the responses of the controls but similar to those of the lower-level-of-cognitive-function schizophrenia group. However, hemodynamic responses in the right DLPFC, bilateral ventrolateral PFC (VLPFC), and right temporal regions decreased with increasing cognitive deficits. In addition, the hemodynamic response correlated positively with the level of cognitive function (BACS composite scores) in the right DLPFC, bilateral VLPFC, right FPC, and bilateral temporal regions in schizophrenia. The correlation was driven by all BACS domains. Our results suggest that the linked functional deficits in the right DLPFC, bilateral VLPFC, right FPC, and bilateral temporal regions may be related to BACS-measured cognitive impairments in schizophrenia and show that linking the neurocognitive deficits and brain abnormalities can increase our understanding of schizophrenia pathophysiology. Copyright © 2015 Elsevier B.V. All rights reserved.

Endothelin-like action of Pausinystalia yohimbe aqueous extract on vascular and renal regional hemodynamics in Sprague Dawley rats.

PubMed

Ajayi, A A; Newaz, M; Hercule, H; Saleh, M; Bode, C O; Oyekan, A O

2003-12-01

The bark of the African tree Pausinystalia yohimbe has been used as a food additive with aphrodisiac and penile erection enhancing properties. The effect of an aqueous extract of P. yohimbe (CCD-X) on renal circulation was assessed in order to test the hypothesis that it possesses additional effects on nitric oxide production and/or endothelin-1 (ET-1)-like actions. In vivo studies with CCD-X in Sprague Dawley rats demonstrated a dose-dependent (1-1000 ng/kg) increase in mean blood pressure (p < 0.001) and an increase in medullary blood flow (MBF) (p < 0.001). Both the pressor action and renal medullary vasodilation were blocked by endothelinA (ETA) receptor antagonist BMS182874 and endothelinB (ETB) receptor antagonist BQ788 in combination. L-Nomega-nitro-l-arginine methyl ester (L-NAME; 10 mg/kg) also inhibited the increase in MBF induced by CCD-X. In vitro studies in isolated perfused kidney and in pressurized renal microvessels confirmed the dose-dependent vasoconstrictor action of this extract. ETA receptor antagonist BQ610 and ETB receptor antagonist BQ788 separately and significantly attenuated the renal vasoconstrictor actions of the extract (p < 0.001 ANOVA). These preliminary observations indicate that, in addition to the alpha-adrenergic antagonist actions that characterize yohimbine, CCD-X possesses endothelin-like actions and affects nitric oxide (NO) production in renal circulation. These findings suggest a strong possibility of post-receptor cross-talk between alpha2-adrenoceptors and endothelin, as well as a direct effect of alpha2-adrenoceptors on renal NO production. (c) 2003 Prous Science

Rationale and design of the Aquapheresis Versus Intravenous Diuretics and Hospitalization for Heart Failure (AVOID-HF) trial.

PubMed

Costanzo, Maria Rosa; Negoianu, Daniel; Fonarow, Gregg C; Jaski, Brian E; Bart, Bradley A; Heywood, J Thomas; Nabut, Jose L; Schollmeyer, Michael P

2015-09-01

In patients hospitalized with acutely decompensated heart failure, unresolved signs and symptoms of fluid overload have been consistently associated with poor outcomes. Regardless of dosing and type of administration, intravenous loop diuretics have not reduced heart failure events or mortality in patients with acutely decompensated heart failure. The results of trials comparing intravenous loop diuretics to mechanical fluid removal by isolated venovenous ultrafiltration have yielded conflicting results. Studies evaluating early decongestive strategies have shown that ultrafiltration removed more fluid and was associated with fewer heart failure-related rehospitalization than intravenous loop diuretics. In contrast, when used in the setting of worsening renal function, ultrafiltration was associated with poorer renal outcomes and no reduction in heart failure events. The AVOID-HF trial seeks to determine if an early strategy of ultrafiltration in patients with acutely decompensated heart failure is associated with fewer heart failure events at 90 days compared with a strategy based on intravenous loop diuretics. Study subjects from 40 highly experienced institutions are randomized to either early ultrafiltration or intravenous loop diuretics. In both treatment arms, fluid removal therapies are adjusted according to the patients' hemodynamic condition and renal function. The study was unilaterally terminated by the sponsor in the absence of futility and safety concerns after the enrollment of 221 subjects, or 27% of the originally planned sample size of 810 patients. The AVOID-HF trial's principal aim is to compare the safety and efficacy of ultrafiltration vs that of intravenous loop diuretics in patients hospitalized with acutely decompensated heart failure. Because stepped treatment approaches are applied in both ultrafiltration and intravenous loop diuretics groups and the primary end point is time to first heart failure event within 90 days, it is hoped that the AVOID-HF trial, despite its untimely termination by the sponsor, will provide further insight on how to optimally decongest patients with fluid-overloaded heart failure. Copyright © 2015. Published by Elsevier Inc.

Rifaximin and midodrine improve clinical outcome in refractory ascites including renal function, weight loss, and short-term survival.

PubMed

Hanafy, Amr S; Hassaneen, Ahmad M

2016-12-01

The occurrence of refractory ascites in nearly 17% of patients with decompensated cirrhosis is an unresolved issue. Advanced liver disease, functional renal impairment, and vascular insensitivity to vasopressors are the main causes of its refractoriness. Therefore, the aim of this study was to evaluate the impact on diuresis, weight loss, and short-term survival if midodrine and rifaximin were added to the diuretic therapy (DT). The study evaluated the eligibility of 650 patients with cirrhosis and refractory ascites who were selected during the period from November 2011 to May 2015. A total of 50 patients were excluded and finally 600 were selected and divided into the following groups: patients exposed to DT (n=200) as a control group, or DT with midodrine and rifaximin group (n=400). Body weight, mean arterial pressure, and glomerular filtration rate were determined. Plasma renin and aldosterone were also determined. Follow-up was performed after 2, 6, and 12 weeks, and then every 2 months for 24 months. The mean arterial pressure was significantly higher in the midodrine and rifaximin group (P=0.000), and there was a highly significant weight loss after 12 weeks (12.5 kg) (P=0.000), a highly significant increase in serum sodium, urine output, and urinary sodium excretion (P=0.000), and creatinine clearance was more reduced in the control group. With rifaximin and midodrine, a complete response occurred in 310 (78%) patients, a partial response in 72 (18%), and no response in 18 (4%) versus 30 (15%), 110 (55%), and 60 (30%) in the control group, respectively (P=0.000). Midodrine and rifaximin significantly reduced paracentesis needs when compared with the controls (18 study patients vs. 75 DT-only patients, P=0.000). Adding rifaximin and midodrine to DT enhanced diuresis in refractory ascites with improved systemic, renal hemodynamics and short-term survival.

Functional MRI Detection of Hemodynamic Response of Repeated Median Nerve Stimulation

PubMed Central

Ai, Leo; Oya, Hiroyuki; Howard, Matthew; Xiong, Jinhu

2012-01-01

Median nerve stimulation is a commonly used technique in the clinical setting to determine areas of neuronal function in the brain. Neuronal activity of repeated median nerve stimulation is well studied. The cerebral hemodynamic response of the stimulation, on the other hand, is not very clear. In this study, we investigate how cerebral hemodynamics behaves over time using the same repeated median nerve stimulation. Ten subjects received constant repeated electrical stimulation to the right median nerve. Each subject had fMRI scans while receiving said stimulations for seven runs. Our results show that the BOLD signal significantly decreases across each run. Significant BOLD signal decreases can also be seen within runs. These results are consistent with studies that have studied the hemodynamic habituation effect with other forms of stimulation. However, the results do not completely agree with the findings of studies where evoked potentials were examined. Thus, further inquiry of how evoked potentials and cerebral hemodynamics are coupled when using constant stimulations is needed. PMID:23228312

Hemodynamic management and outcome of patients treated for cerebral vasospasm with intraarterial nicardipine and/or milrinone.

PubMed

Schmidt, Ulrich; Bittner, Edward; Pivi, Silvia; Marota, John J A

2010-03-01

Vasospasm is a potentially devastating complication after aneurysmal subarachnoid hemorrhage. Although endovascular treatment with intraarterial nicardipine and milrinone is an accepted clinical treatment strategy, there is little information either on hemodynamic management during treatment or on outcome and consequences of the hemodynamic management. We tested 2 hypotheses: (1) intraarterial administration of nicardipine and milrinone to treat cerebral vasospasm would require increased administration of vasoconstrictor to support arterial blood pressure at target levels; and (2) high-dose vasopressors administered to increase blood pressure in these patients would lead to systemic acidosis and end-organ ischemic damage. We conducted a single-center, retrospective review of consecutive patients with clinically symptomatic vasospasm after aneurysmal subarachnoid hemorrhage that failed medical management with "triple H therapy" and subsequently received intraarterial nicardipine and/or milrinone between March 2005 and July 2007. Of 160 endovascular interventions in 73 patients (aged 52 +/- 10 years; 50 women), 96 received only nicardipine, 5 only milrinone, and 59 both drugs. General anesthesia with muscle relaxation was performed for 93% of procedures. During treatment, both the number and dose of vasopressors required to maintain arterial blood pressure at target levels increased; the median dose of phenylephrine increased from 200 (n = 121) to 325 microg/min (n = 122), norepinephrine increased from 12 (n = 60) to 24.5 microg/min (n = 87), and vasopressin infusions increased from 7 to 24. Nonetheless, arterial blood pressure decreased 13% during treatment. In >90% of procedures, the postprocedure angiogram showed improved vessel caliber. A single patient demonstrated troponin T increase; no patients had a decrease in renal function, bowel or peripheral ischemia, systemic acidosis, or acute stroke. Overall mortality was 11%. Intraarterial administration of nicardipine and/or milrinone requires use of vasopressors to maintain arterial blood pressure. Despite high doses of vasoconstrictors, treatment has low mortality, minimal end-organ ischemic damage or systemic acidosis, and results in improved caliber of cerebral vessels affected by vasospasm.

RAAS inhibition and cardiorenal syndrome.

PubMed

Onuigbo, Macaulay Amechi C

2014-01-01

The consensus conference on cardio-renal syndromes (2008) defined 'cardio-renal syndromes' as 'disorders of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other' and identified five subtypes of the syndromes. Various pathophysiologic mechanisms underlie cardiorenal syndrome including hemodynamic derangements, reduced cardiac output leading to impaired renal perfusion, reduced stroke volume, raised atrial filling pressures, elevated atrial pressures, sodium and water retention, venous congestion, right ventricular dysfunction and venous hypertension causing increased renal venous pressure, intra-abdominal hypertension, various neurohormonal adaptations including activation of the renin-angiotensin-aldosterone system, adaptive activation of the sympathetic nervous system, cytokine release and oxidative stress. Although there are standardized clinical guidelines for the management of heart failure, and chronic kidney disease, respectively, there are no similar consensus clinical guidelines for the management of the cardiorenal syndromes. RAAS inhibition is advocated in treating systolic heart failure. There is evidence that RAAS inhibition is also useful in cardiorenal syndrome. However, RAAS inhibition, while potentially useful in the management of cardiorenal syndrome, is not the 'magic bullet', is sometimes limited by adverse renal events, is not applicable to all patients, and must be applied by physicians with due diligence and caution. Nevertheless, a more comprehensive multidisciplinary multipronged approach to managing patients with cardiorenal syndrome is even more pragmatic and commonsense given the multiple mechanisms and pathogenetic pathways implicated in the causation and perpetuation of cardiorenal syndrome.

Swine in biomedical research. Vol. 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tumbleson, M.E.

This volume presents information on the following topics: hemodynamic characteristics of the conscious resting pig; cardiovascular and metabolic responses to acute and chronic exercise in swine (ILLEGIBLE) a large animal model for studies (ILLEGIBLE) effects of heparin-protamine interaction in swine - intravenous vs. intraarterial; swine as animal models in cardiovascular research; studies of coronary thrombosis in swine with von Willebrand's disease; role of plasma intermediate and low density lipoproteins in early atherogenesis in hyperlipidemic swine; swine as a model in renal physiology and nephrology; the pig as a model for studying kidney disease in man; hypertension of renal origin andmore » the effects of Captopril in miniature pigs; porcine natural killer/killer cell system; the behavior of pig lymphocyte populations in vivo; a review of spontaneous and experimental porcine eperythrozoonosis; and Sinclair swine melanoma.« less

[Renal physiology].

PubMed

Gueutin, Victor; Deray, Gilbert; Isnard-Bagnis, Corinne

2012-03-01

The kidneys are responsible for the urinary excretion of uremic toxins and the regulation of several body systems such as intra and extracellular volume status, acid-base status, calcium and phosphate metabolism or erythropoiesis. They adapt quantitative and qualitative composition of the urine to keep these systems in balance. The flow of plasma is filtered in the range of 120 mL/min, and depends on the systemic and renal hemodynamics which is subject to self-regulation. The original urine will then be modified in successive segments of the nephron. The proximal nephron is to lead the massive reabsorption of water and essential elements such as sodium, bicarbonates, amino-acids and glucose. The distal nephron includes the distal convoluted tubule, the connector tube and the collecting duct. Its role is to adapt the quality composition of urine to the needs of the body.

Exploration of the Rapid Effects of Personal Fine Particulate Matter Exposure on Hemodynamics and Vascular Function during the Same Day

EPA Science Inventory

Background: Levels of fine particulate matter [≤ 2.5 μm in aerodynamic diameter (PM_2.5)] are associated with alterations in arterial hemodynamics and vascular function. However, the characteristics of the same-day exposure–response relationships remain unclear. Object...

Home Discharge and Out-of-Hospital Follow-Up of Total Artificial Heart Patients Supported by a Portable Driver System

PubMed Central

2014-01-01

To enhance ambulation and facilitate hospital discharge of total artificial heart (TAH)–supported patients, we adapted a mobile ventricular assistance device (VAD) driver (Excor) for TAH use and report on the performance of Excor-driven TAH patients discharged home. Ten patients stabilized on a TAH, driven by the CSS (“Circulatory Support System”), were progressively switched over to the Excor in hospital over 14 days as a pilot, with daily hemodynamics and laboratory parameters measured. Twenty-two stable TAH patients were subsequently placed on the Excor, trained, and discharged home. Clinical and hemodynamic parameters were followed. All pilot study patients were clinically stable on the Excor, with no decrease in TAH output noted (6.3 + 0.3 L/min [day 1] vs. 5.8 + 0.2 L/min [day 14], p = 0.174), with a trend suggesting improvement of both hepatic and renal function. Twenty-two TAH patients were subsequently successfully discharged home on the portable driver and were supported out of hospital for up to 598 days (range, 2–598; mean = 179 ± 140 days), remaining ambulatory, New York Heart Association (NYHA) class I or II, and free of readmission for 88.5% of the time of support. TAH patients may be effectively and safely supported by a mobile drive system. As such, the utility of the TAH may be extended to support patients beyond the hospital, at home, with overall ambulatory freedom. PMID:24577369

A computational simulation of the effect of hybrid treatment for thoracoabdominal aortic aneurysm on the hemodynamics of abdominal aorta

NASA Astrophysics Data System (ADS)

Wen, Jun; Yuan, Ding; Wang, Qingyuan; Hu, Yao; Zhao, Jichun; Zheng, Tinghui; Fan, Yubo

2016-03-01

Hybrid visceral-renal debranching procedures with endovascular repair have been proposed as an appealing technique to treat conventional thoracoabdominal aortic aneurysm (TAAA). This approach, however, still remained controversial because of the non-physiological blood flow direction of its retrograde visceral revascularization (RVR) which is generally constructed from the aortic bifurcation or common iliac artery. The current study carried out the numerical simulation to investigate the effect of RVR on the hemodynamics of abdominal aorta. The results indicated that the inflow sites for the RVR have great impact on the hemodynamic performance. When RVR was from the distal aorta, the perfusion to visceral organs were adequate but the flow flux to the iliac artery significantly decreased and a complex disturbed flow field developed at the distal aorta, which endangered the aorta at high risk of aneurysm development. When RVR was from the right iliac artery, the abdominal aorta was not troubled with low WSS or disturbed flow, but the inadequate perfusion to the visceral organs reached up to 40% and low WSS and flow velocity predominated appeared at the right iliac artery and the grafts, which may result in the stenosis in grafts and aneurysm growth on the host iliac artery.

Evaluation of renal function in patients with a main renal stone larger than 1 cm and perioperative renal functional change in minimally invasive renal stone surgery: a prospective, observational study.

PubMed

Piao, Songzhe; Park, Juhyun; Son, Hwancheol; Jeong, Hyeon; Cho, Sung Yong

2016-05-01

To compare the perioperative relative renal function and determine predictors of deterioration and recovery of separate renal function in patients with renal stones >10 mm and who underwent mini-percutaneous nephrolithotomy or retrograde intra-renal surgery. A main stone >10 mm or stones growing, high-risk stone formers and extracorporeal shock-wave lithotripsy-resistant stones were prospectively included in 148 patients. Patients with bilateral renal stones and anatomical deformities were excluded. Renal function was evaluated by estimated glomerular filtration rate, 99m-technetium dimercaptosuccinic acid and 99m-technetium diethylenetriamine pentaacetate prior to intervention and at postoperative 3 months. Logistic regression analyses were performed to find predictors of functional deterioration and recovery. The overall stone-free rate was 85.1 %. A third of patients (53/148, 35.8 %) with renal stones >10 mm showed deterioration of separate renal function. Mean renal function of operative sites showed 58.2 % (36.8 %/63.2 %) of that of contralateral sites in these patients. Abnormal separate renal function showed postoperative recovery in 31 patients (58.5 %). Three cases (5.7 %) showed deterioration of separate renal function despite no presence of remnant stones. Improvement rates of the abnormal separate renal function did not differ according to the type of surgery. The presence of hydronephrosis and three or more stones were significant predictors for renal function deterioration. Female gender and three or more stones were significantly correlated with postoperative recovery. Mini-percutaneous nephrolithotomy or retrograde intra-renal surgery was effective and safe for renal function preservation. Patients with multiple large stones should be considered for candidates of active surgical removal.

A randomized, controlled, double-blind crossover study on the effects of 1-L infusions of 6% hydroxyethyl starch suspended in 0.9% saline (voluven) and a balanced solution (Plasma Volume Redibag) on blood volume, renal blood flow velocity, and renal cortical tissue perfusion in healthy volunteers.

PubMed

Chowdhury, Abeed H; Cox, Eleanor F; Francis, Susan T; Lobo, Dileep N

2014-05-01

We compared the effects of intravenous administration of 6% hydroxyethyl starch (maize-derived) in 0.9% saline (Voluven; Fresenius Kabi, Runcorn, United Kingdom) and a "balanced" preparation of 6% hydroxyethyl starch (potato-derived) [Plasma Volume Redibag (PVR); Baxter Healthcare, Thetford, United Kingdom] on renal blood flow velocity and renal cortical tissue perfusion in humans using magnetic resonance imaging. Hyperchloremia resulting from 0.9% saline infusion may adversely affect renal hemodynamics when compared with balanced crystalloids. This phenomenon has not been studied with colloids. Twelve healthy adult male subjects received 1-L intravenous infusions of Voluven or PVR over 30 minutes in a randomized, double-blind manner, with crossover studies 7 to 10 days later. Magnetic resonance imaging proceeded for 60 minutes after commencement of infusion to measure renal artery blood flow velocity and renal cortical perfusion. Blood was sampled, and weight was recorded at 0, 30, 60, 120, 180, and 240 minutes. Mean peak serum chloride concentrations were 108 and 106 mmol/L, respectively, after Voluven and PVR infusion (P = 0.032). Changes in blood volume (P = 0.867), strong ion difference (P = 0.219), and mean renal artery flow velocity (P = 0.319) were similar. However, there was a significant increase in mean renal cortical tissue perfusion after PVR when compared with Voluven (P = 0.033). There was no difference in urinary neutrophil gelatinase-associated liopcalin to creatinine ratios after the infusion (P = 0.164). There was no difference in the blood volume-expanding properties of the 2 preparations of 6% hydroxyethyl starch. The balanced starch produced an increase in renal cortical tissue perfusion, a phenomenon not seen with starch in 0.9% saline.

Functional Connectivity of Resting Hemodynamic Signals in Submillimeter Orientation Columns of the Visual Cortex.

PubMed

Vasireddi, Anil K; Vazquez, Alberto L; Whitney, David E; Fukuda, Mitsuhiro; Kim, Seong-Gi

2016-09-07

Resting-state functional magnetic resonance imaging has been increasingly used for examining connectivity across brain regions. The spatial scale by which hemodynamic imaging can resolve functional connections at rest remains unknown. To examine this issue, deoxyhemoglobin-weighted intrinsic optical imaging data were acquired from the visual cortex of lightly anesthetized ferrets. The neural activity of orientation domains, which span a distance of 0.7-0.8 mm, has been shown to be correlated during evoked activity and at rest. We performed separate analyses to assess the degree to which the spatial and temporal characteristics of spontaneous hemodynamic signals depend on the known functional organization of orientation columns. As a control, artificial orientation column maps were generated. Spatially, resting hemodynamic patterns showed a higher spatial resemblance to iso-orientation maps than artificially generated maps. Temporally, a correlation analysis was used to establish whether iso-orientation domains are more correlated than orthogonal orientation domains. After accounting for a significant decrease in correlation as a function of distance, a small but significant temporal correlation between iso-orientation domains was found, which decreased with increasing difference in orientation preference. This dependence was abolished when using artificially synthetized orientation maps. Finally, the temporal correlation coefficient as a function of orientation difference at rest showed a correspondence with that calculated during visual stimulation suggesting that the strength of resting connectivity is related to the strength of the visual stimulation response. Our results suggest that temporal coherence of hemodynamic signals measured by optical imaging of intrinsic signals exists at a submillimeter columnar scale in resting state.

Influence of CT-based depth correction of renal scintigraphy in evaluation of living kidney donors on side selection and postoperative renal function: is it necessary to know the relative renal function?

PubMed

Weinberger, Sarah; Klarholz-Pevere, Carola; Liefeldt, Lutz; Baeder, Michael; Steckhan, Nico; Friedersdorff, Frank

2018-03-22

To analyse the influence of CT-based depth correction in the assessment of split renal function in potential living kidney donors. In 116 consecutive living kidney donors preoperative split renal function was assessed using the CT-based depth correction. Influence on donor side selection and postoperative renal function of the living kidney donors were analyzed. Linear regression analysis was performed to identify predictors of postoperative renal function. A left versus right kidney depth variation of more than 1 cm was found in 40/114 donors (35%). 11 patients (10%) had a difference of more than 5% in relative renal function after depth correction. Kidney depth variation and changes in relative renal function after depth correction would have had influence on side selection in 30 of 114 living kidney donors. CT depth correction did not improve the predictability of postoperative renal function of the living kidney donor. In general, it was not possible to predict the postoperative renal function from preoperative total and relative renal function. In multivariate linear regression analysis, age and BMI were identified as most important predictors for postoperative renal function of the living kidney donors. Our results clearly indicate that concerning the postoperative renal function of living kidney donors, the relative renal function of the donated kidney seems to be less important than other factors. A multimodal assessment with consideration of all available results including kidney size, location of the kidney and split renal function remains necessary.

Are Non-Newtonian Effects Important in Hemodynamic Simulations of Patients With Autogenous Fistula?

PubMed Central

Javid Mahmoudzadeh Akherat, S. M.; Cassel, Kevin; Boghosian, Michael; Dhar, Promila; Hammes, Mary

2017-01-01

Given the current emphasis on accurate computational fluid dynamics (CFD) modeling of cardiovascular flows, which incorporates realistic blood vessel geometries and cardiac waveforms, it is necessary to revisit the conventional wisdom regarding the influences of non-Newtonian effects. In this study, patient-specific reconstructed 3D geometries, whole blood viscosity data, and venous pulses postdialysis access surgery are used as the basis for the hemodynamic simulations of renal failure patients with native fistula access. Rheological analysis of the viscometry data initially suggested that the correct choice of constitutive relations to capture the non-Newtonian behavior of blood is important because the end-stage renal disease (ESRD) patient cohort under observation experience drastic variations in hematocrit (Hct) levels and whole blood viscosity throughout the hemodialysis treatment. For this purpose, various constitutive relations have been tested and implemented in CFD practice, namely Quemada and Casson. Because of the specific interest in neointimal hyperplasia and the onset of stenosis in this study, particular attention is placed on differences in nonhomeostatic wall shear stress (WSS) as that drives the venous adaptation process that leads to venous geometric evolution over time in ESRD patients. Surprisingly, the CFD results exhibit no major differences in the flow field and general flow characteristics of a non-Newtonian simulation and a corresponding identical Newtonian counterpart. It is found that the vein's geometric features and the dialysis-induced flow rate have far greater influence on the WSS distribution within the numerical domain. PMID:28249082

Are Non-Newtonian Effects Important in Hemodynamic Simulations of Patients With Autogenous Fistula?

PubMed

Javid Mahmoudzadeh Akherat, S M; Cassel, Kevin; Boghosian, Michael; Dhar, Promila; Hammes, Mary

2017-04-01

Given the current emphasis on accurate computational fluid dynamics (CFD) modeling of cardiovascular flows, which incorporates realistic blood vessel geometries and cardiac waveforms, it is necessary to revisit the conventional wisdom regarding the influences of non-Newtonian effects. In this study, patient-specific reconstructed 3D geometries, whole blood viscosity data, and venous pulses postdialysis access surgery are used as the basis for the hemodynamic simulations of renal failure patients with native fistula access. Rheological analysis of the viscometry data initially suggested that the correct choice of constitutive relations to capture the non-Newtonian behavior of blood is important because the end-stage renal disease (ESRD) patient cohort under observation experience drastic variations in hematocrit (Hct) levels and whole blood viscosity throughout the hemodialysis treatment. For this purpose, various constitutive relations have been tested and implemented in CFD practice, namely Quemada and Casson. Because of the specific interest in neointimal hyperplasia and the onset of stenosis in this study, particular attention is placed on differences in nonhomeostatic wall shear stress (WSS) as that drives the venous adaptation process that leads to venous geometric evolution over time in ESRD patients. Surprisingly, the CFD results exhibit no major differences in the flow field and general flow characteristics of a non-Newtonian simulation and a corresponding identical Newtonian counterpart. It is found that the vein's geometric features and the dialysis-induced flow rate have far greater influence on the WSS distribution within the numerical domain.

A Unified Theory of Sepsis-Induced Acute Kidney Injury: Inflammation, microcirculatory dysfunction, bioenergetics and the tubular cell adaptation to injury

PubMed Central

Gomez, Hernando; Ince, Can; De Backer, Daniel; Pickkers, Peter; Payen, Didier; Hotchkiss, John; Kellum, John A.

2014-01-01

Given that the leading clinical conditions associated with Acute kidney injury (AKI), namely, sepsis, major surgery, heart failure and hypovolemia, are all associated with shock, it is tempting to attribute all AKI to ischemia on the basis of macro-hemodynamic changes. However, an increasing body of evidence has suggested that in many patients, AKI can occur in the absence of overt signs of global renal hypoperfusion. Indeed, sepsis-induced AKI can occur in the setting of normal or even increased renal blood flow. Accordingly, renal injury may not be entirely explained solely on the basis of the classic paradigm of hypoperfusion, and thus other mechanisms must come into play. Herein, we put forward a “unifying theory” to explain the interplay between inflammation and oxidative stress, microvascular dysfunction, and the adaptive response of the tubular epithelial cell to the septic insult. We propose that this response is mostly adaptive in origin, that it is driven by mitochondria and that it ultimately results in and explains the clinical phenotype of sepsis induced AKI. PMID:24346647

Evidence of low dimensional chaos in renal blood flow control in genetic and experimental hypertension

NASA Astrophysics Data System (ADS)

Yip, K.-P.; Marsh, D. J.; Holstein-Rathlou, N.-H.

1995-01-01

We applied a surrogate data technique to test for nonlinear structure in spontaneous fluctuations of hydrostatic pressure in renal tubules of hypertensive rats. Tubular pressure oscillates at 0.03-0.05 Hz in animals with normal blood pressure, but the fluctuations become irregular with chronic hypertension. Using time series from rats with hypertension we produced surrogate data sets to test whether they represent linearly correlated noise or ‘static’ nonlinear transforms of a linear stochastic process. The correlation dimension and the forecasting error were used as discriminating statistics to compare surrogate with experimental data. The results show that the original experimental time series can be distinguished from both linearly and static nonlinearly correlated noise, indicating that the nonlinear behavior is due to the intrinsic dynamics of the system. Together with other evidence this strongly suggests that a low dimensional chaotic attractor governs renal hemodynamics in hypertension. This appears to be the first demonstration of a transition to chaotic dynamics in an integrated physiological control system occurring in association with a pathological condition.

Dehydration, hemodynamics and fluid volume optimization after induction of general anesthesia.

PubMed

Li, Yuhong; He, Rui; Ying, Xiaojiang; Hahn, Robert G

2014-01-01

Fluid volume optimization guided by stroke volume measurements reduces complications of colorectal and high-risk surgeries. We studied whether dehydration or a strong hemodynamic response to general anesthesia increases the probability of fluid responsiveness before surgery begins. Cardiac output, stroke volume, central venous pressure and arterial pressures were measured in 111 patients before general anesthesia (baseline), after induction and stepwise after three bolus infusions of 3 ml/kg of 6% hydroxyethyl starch 130/0.4 (n=86) or Ringer's lactate (n=25). A subgroup of 30 patients who received starch were preloaded with 500 ml of Ringer's lactate. Blood volume changes were estimated from the hemoglobin concentration and dehydration was estimated from evidence of renal water conservation in urine samples. Induction of anesthesia decreased the stroke volume to 62% of baseline (mean); administration of fluids restored this value to 84% (starch) and 68% (Ringer's). The optimized stroke volume index was clustered around 35-40 ml/m2/beat. Additional fluid boluses increased the stroke volume by ≥10% (a sign of fluid responsiveness) in patients with dehydration, as suggested by a low cardiac index and central venous pressure at baseline and by high urinary osmolality, creatinine concentration and specific gravity. Preloading and the hemodynamic response to induction did not correlate with fluid responsiveness. The blood volume expanded 2.3 (starch) and 1.8 (Ringer's) times over the infused volume. Fluid volume optimization did not induce a hyperkinetic state but ameliorated the decrease in stroke volume caused by anesthesia. Dehydration, but not the hemodynamic response to the induction, was correlated with fluid responsiveness.

Dynamic model for the tissue concentration and oxygen saturation of hemoglobin in relation to blood volume, flow velocity, and oxygen consumption: Implications for functional neuroimaging and coherent hemodynamics spectroscopy (CHS).

PubMed

Fantini, Sergio

2014-01-15

This article presents a dynamic model that quantifies the temporal evolution of the concentration and oxygen saturation of hemoglobin in tissue, as determined by time-varying hemodynamic and metabolic parameters: blood volume, flow velocity, and oxygen consumption. This multi-compartment model determines separate contributions from arterioles, capillaries, and venules that comprise the tissue microvasculature, and treats them as a complete network, without making assumptions on the details of the architecture and morphology of the microvascular bed. A key parameter in the model is the effective blood transit time through the capillaries and its associated probability of oxygen release from hemoglobin to tissue, as described by a rate constant for oxygen diffusion. The solution of the model in the time domain predicts the signals measured by hemodynamic-based neuroimaging techniques such as functional near-infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) in response to brain activation. In the frequency domain, the model yields an analytical solution based on a phasor representation that provides a framework for quantitative spectroscopy of coherent hemodynamic oscillations. I term this novel technique coherent hemodynamics spectroscopy (CHS), and this article describes how it can be used for the assessment of cerebral autoregulation and the study of hemodynamic oscillations resulting from a variety of periodic physiological challenges, brain activation protocols, or physical maneuvers. Copyright © 2013 Elsevier Inc. All rights reserved.

Dynamic model for the tissue concentration and oxygen saturation of hemoglobin in relation to blood volume, flow velocity, and oxygen consumption: Implications for functional neuroimaging and coherent hemodynamics spectroscopy (CHS)

PubMed Central

Fantini, Sergio

2013-01-01

This article presents a dynamic model that quantifies the temporal evolution of the concentration and oxygen saturation of hemoglobin in tissue, as determined by time-varying hemodynamic and metabolic parameters: blood volume, flow velocity, and oxygen consumption. This multi-compartment model determines separate contributions from arterioles, capillaries, and venules that comprise the tissue microvasculature, and treats them as a complete network, without making assumptions on the details of the architecture and morphology of the microvascular bed. A key parameter in the model is the effective blood transit time through the capillaries and its associated probability of oxygen release from hemoglobin to tissue, as described by a rate constant for oxygen diffusion. The solution of the model in the time domain predicts the signals measured by hemodynamic-based neuroimaging techniques such as functional near-infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) in response to brain activation. In the frequency domain, the model yields an analytical solution based on a phasor representation that provides a framework for quantitative spectroscopy of coherent hemodynamic oscillations. I term this novel technique coherent hemodynamics spectroscopy (CHS), and this article describes how it can be used for the assessment of cerebral autoregulation and the study of hemodynamic oscillations resulting from a variety of periodic physiological challenges, brain activation protocols, or physical maneuvers. PMID:23583744

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cuocolo, A.; Esposito, S.; Volpe, M.

We studied 11 hypertensive patients by a radionuclide technique using Gates' method with (/sup 99m/Tc)DTPA to investigate the acute effects of captopril on glomerular filtration rate (GFR). Five patients had hypertension with unilateral renal artery stenosis (RAS) angiographically documented and six patients had essential hypertension (EH). Total and split GFR were determined under control conditions and after oral administration of captopril (50 mg). In the patients with RAS, captopril induced a significant decrease of GFR in the stenotic kidneys (from 42.4 +/- 4 to 29.6 +/- 3 ml/min, p less than 0.01), while no changes were observed in the nonstenoticmore » kidneys (from 61.2 +/- 3 to 61.6 +/- 5 ml/min, NS). Total GFR was 103.6 +/- 5 ml/min under control conditions and decreased to 91.8 +/- 6 ml/min after captopril (p less than 0.05). No significant changes of GFR were detected after captopril administration in patients with EH. In a separate group of ten patients with EH, good correlation between 24-hr creatinine clearance and fractional uptake of (/sup 99m/Tc)DTPA was obtained. Good reproducibility of this radionuclide technique was also shown. This study demonstrates that the computed radionuclide GFR determination coupled with the captopril test allows one to unmask angiotensin II-dependent renal function and hemodynamic changes. This technique can be useful in clinical practice for identifying patients with renovascular hypertension.« less

Effect of L-dopa decarboxylase inhibitor benserazide on renal function in streptozotocin-diabetic rats.

PubMed

Pfeil, Katrin; Staudacher, Torsten; Luippold, Gerd

2006-01-01

Benserazide (BZD), an inhibitor of the dopamine synthesis, abolished the increase in glomerular filtration rate (GFR) following the infusion of a mixed amino acid solution. These results reveal endogenous dopamine as a mediator in the renal response to amino acids. The aim of the present study was to evaluate whether dopamine is also involved in the regulation of glomerular hyperfiltration during the early state of diabetes mellitus (DM). Male Sprague-Dawley rats were injected with a single dose of streptozotocin (60 mg/kg i.p.) for induction of experimental DM (n = 7-8/group). Age-matched non-diabetic animals, injected with citrate buffer, served as controls (CON, n = 8/group). Clearance experiments were performed 2 weeks after induction of DM in thiopental-anesthetized rats (80 mg/kg i.p.), which were continuously infused either with BZD (30 microg/min/kg) or vehicle (VHC). Mean arterial blood pressure was around 110 mm Hg and did not significantly differ among the groups. GFR was 0.95 +/- 0.02 ml/min/100 g b.w. in VHC-treated CON. BZD treatment did not significantly change GFR in the CON group (0.92 +/- 0.06 ml/min/100 g b.w.). As expected, glomerular hyperfiltration was observed in diabetic rats infused with VHC (1.24 +/- 0.08 ml/min/100 g b.w.). Treatment with BZD significantly reduced the diabetes-induced increase in GFR to control levels (0.95 +/- 0.05 ml/min/100 g b.w.). Our results show that the inhibition of dopamine synthesis prevented the increase in GFR due to diabetic conditions, indicating that endogenous dopamine is involved in the regulation of DM-induced changes in renal hemodynamics. Copyright 2006 S. Karger AG, Basel.

The hemodynamic changes in the human prefrontal cortex during the Flanker and Simon tasks: a fNIRS study

NASA Astrophysics Data System (ADS)

Yuan, Zhen; Lin, Xiaohong

2016-03-01

Functional near-infrared spectroscopy (fNIRS) is a low-cost, portable and noninvasive functional neuroimaging technique by measuring the change in the concentrations of oxyhemoglobin (HbO) and deoxyhemoglobin (HbR). The aim of present study is to reveal the different brain activity pattern of adult subjects during the completion of flanker and Simon tasks underlying the congruent and incongruent test conditions so as to identify the basic neural mechanism of inhibitory control in executive function. In the study, we utilized fNIRS to explore the hemodynamic changes in the prefrontal cortex and our imaging results suggested that there were notable differences for the hemodynamic responses between the flank and Simon task. A striking difference is that for the flank task, the increase in the HbO concentration during incongruent trials was larger than that during congruent trials for the channels across middle frontal cortex while for the Simon task, the hemodynamic response was stronger for the congruent condition compared to that from the incongruent one. Interestingly, the hemodynamic response exhibited similar task-related activation in the superior frontal cortex for both the congruent and incongruent conditions. Further, independent component analysis showed that different brain activation patterns were identified to accomplish different inhibitory control tasks underlying the congruent and incongruent conditions.

Effects of intravenous bolus injection of nicorandil on renal artery flow velocity assessed by color Doppler ultrasound.

PubMed

Shimamoto, Yukiko; Kubo, Takashi; Tanabe, Kazumi; Emori, Hiroki; Katayama, Yosuke; Nishiguchi, Tsuyoshi; Taruya, Akira; Kameyama, Takeyoshi; Orii, Makoto; Yamano, Takashi; Kuroi, Akio; Yamaguchi, Tomoyuki; Takemoto, Kazushi; Matsuo, Yoshiki; Ino, Yasushi; Tanaka, Atsushi; Hozumi, Takeshi; Terada, Masaki; Akasaka, Takashi

2017-01-01

Previous animal studies have shown that a potassium channel opener, nicorandil, provokes vasodilation in renal microvasculature and increases renal blood flow. We conducted a clinical study that aimed to evaluate the effect of nicorandil on renal artery blood flow in comparison with nitroglycerin by using color Doppler ultrasound. The present study enrolled 40 patients with stable coronary artery disease who had no renal arterial stenosis and renal parenchymal disease. The patients received intravenous administration of nicorandil (n=20) or nitroglycerin (n=20). Before and after the administration, renal artery blood flow velocity was measured by color-guided pulsed-wave Doppler. The peak-systolic, end-diastolic, and mean renal artery blood flow velocities before the administration were not different between the nicorandil group and the nitroglycerin group. The peak-systolic (79±15cm/s to 99±21cm/s, p<0.001; and 78±19cm/s to 85±19cm/s, p=0.004), end-diastolic (22±5cm/s to 28±8cm/s, p<0.001; and 24±6cm/s to 26±6cm/s, p=0.005) and mean (41±6cm/s to 49±9cm/s, p<0.001; and 43±9cm/s to 45±9cm/s, p=0.009) renal artery flow velocities increased significantly in either group. The nominal changes in the peak-systolic (20±10cm/s vs. 7±8cm/s, p<0.001), end-diastolic (5±4cm/s vs. 2±3cm/s, p=0.001), and mean (8±5cm/s vs. 2±2cm/s, p<0.001) renal artery blood flow velocities were significantly greater in the nicorandil group compared with the nitroglycerin group. Intravenous nicorandil increased renal artery blood flow velocity in comparison with nitroglycerin. Nicorandil has a significant effect on renal hemodynamics. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Angiotensin II activates collagen type I gene in the renal vasculature of transgenic mice during inhibition of nitric oxide synthesis: evidence for an endothelin-mediated mechanism.

PubMed

Boffa, J J; Tharaux, P L; Placier, S; Ardaillou, R; Dussaule, J C; Chatziantoniou, C

1999-11-02

Hypertension is frequently associated with renal vascular fibrosis. The purpose of this study was to investigate whether angiotensin II (Ang II) is involved in this fibrogenic process. Experiments were performed on transgenic mice harboring the luciferase gene under the control of the collagen I-alpha(2) chain promoter [procolalpha(2)(I)]. Hypertension was induced by chronic inhibition of NO synthesis (N(G)-nitro-L-arginine methyl ester, L-NAME). Procolalpha(2)(I) activity started to increase in the renal vasculature after 4 weeks of L-NAME treatment (P<0.01) and at 14 weeks reached 3- and 8-fold increases over control in afferent arterioles and glomeruli, respectively (P<0.001). Losartan, an AT(1) receptor antagonist, given simultaneously with L-NAME prevented the increase of procolalpha(2)(I) levels and attenuated the development of renal vascular fibrosis without normalizing systolic pressure increase. Because we found previously that endothelin mediated renal vascular fibrosis in the L-NAME model, the interaction between Ang II, endothelin, and procolalpha(2)(I) was investigated in ex vivo and short-term in vivo experiments. In both conditions, the Ang II-induced activation of procolalpha(2)(I) in renal cortex was blocked by an endothelin receptor antagonist. During chronic inhibition of NO, the collagen I gene becomes activated, leading to the development of renal vascular fibrosis. Ang II is a major player in this fibrogenic process, and its effect on collagen I gene is independent of systemic hemodynamics and is at least partly mediated by the profibrogenic action of endothelin.

Gender-specific hemodynamics in prefrontal cortex during a verbal working memory task by near-infrared spectroscopy.

PubMed

Li, Ting; Luo, Qingming; Gong, Hui

2010-05-01

The presence or absence of gender differences in working memory, localized in the prefrontal cortex (PFC), has been debated in a few fMRI studies. However, the hypothesis of gender differences in PFC function has not been elaborated, and comparisons among hemodynamic parameters designed to test for gender differences are scarce. We utilized near-infrared spectroscopy during verbal N-back tasks on 26 male and 24 female healthy volunteers. Changes in the concentrations of oxy- (Delta[oxy-Hb]), deoxy- (Delta[deoxy-Hb]) and total hemoglobin (Delta[tot-Hb]) were recorded simultaneously. Delta[oxy-Hb] and Delta[tot-Hb] exhibited obvious gender differences, but Delta[deoxy-Hb] did not. Males showed bilateral activation with slight left-side dominance, whereas females showed left activation. The activation in males was more wide-spread and stronger than in females. Furthermore, females required a lower hemodynamic supply than males to obtain comparable performance, and only females exhibited positive correlations between hemodynamic parameters and behavioral performance. The results reinforce the existence of a gender effect in hemodynamic-based functional imaging studies. Our findings suggest that females possess more efficient hemodynamics in the PFC during working memory and emphasize the importance of studying the PFC to further a scientific understanding of gender differences.

Association between hemodynamic activity and motor performance in six-month-old full-term and preterm infants: a functional near-infrared spectroscopy study.

PubMed

de Oliveira, Suelen Rosa; de Paula Machado, Ana Carolina Cabral; de Paula, Jonas Jardim; de Moraes, Paulo Henrique Paiva; Nahin, Maria Juliana Silvério; Magalhães, Lívia de Castro; Novi, Sergio L; Mesquita, Rickson C; de Miranda, Débora Marques; Bouzada, Maria Cândida Ferrarez

2018-01-01

This study aimed to assess task-induced activation in motor cortex and its association with motor performance in full-term and preterm born infants at six months old. A cross-sectional study of 73 six-month-old infants was conducted (35 full-term and 38 preterm infants). Motor performance was assessed using the Bayley Scales of Infant Development third edition-Bayley-III. Brain hemodynamic activity during motor task was measured by functional near-infrared spectroscopy (fNIRS). Motor performance was similar in full-term and preterm infants. However, differences in hemodynamic response were identified. Full terms showed a more homogeneous unilateral and contralateral activated area, whereas in preterm-born the activation response was predominantly bilateral. The full-term group also exhibited a shorter latency for the hemodynamic response than the preterm group. Hemodynamic activity in the left sensorimotor region was positively associated with motor performance measured by Bayley-III. The results highlight the adequacy of fNIRS to assess differences in task-induced activation in sensorimotor cortex between groups. The association between motor performance and the hemodynamic activity require further investigation and suggest that fNIRS can become a suitable auxiliary tool to investigate aspects of neural basis on early development of motor abilities.

Allopurinol attenuates acute kidney injury following Bothrops jararaca envenomation

PubMed Central

Martines, Monique Silva; Ferreira, Daniela; Volpini, Rildo; Canale, Daniele; Malaque, Ceila; Crajoinas, Renato; Girardi, Adriana Castello Costa; Massola Shimizu, Maria Heloisa; Seguro, Antonio Carlos

2017-01-01

Snakebites have been recognized as a neglected public health problem in several tropical and subtropical countries. Bothrops snakebites frequently complicate with acute kidney injury (AKI) with relevant morbidity and mortality. To date, the only treatment available for Bothrops envenomation is the intravenous administration of antivenom despite its several limitations. Therefore, the study of novel therapies in Bothrops envenomation is compelling. The aim of this study was to evaluate the protective effect of Allopurinol (Allo) in an experimental model of Bothrops jararaca venom (BJ)-associated AKI. Five groups of Wistar rats were studied: Sham, Allo, BJ, BJ+Allo, BJ+ipAllo. BJ (0.25 mg/kg) was intravenously injected during 40’. Saline at same dose and infusion rate was administered to Sham and Allo groups. Allo and BJ+Allo groups received Allo (300 mg/L) in the drinking water 7 days prior to Saline or BJ infusion respectively. BJ+ipAllo rats received intraperitoneal Allo (25 mg/Kg) 40’ after BJ infusion. BJ rats showed markedly reduced glomerular filtration rate (GFR, inulin clearance) associated with intense renal vasoconstriction, hemolysis, hemoglobinuria, reduced glutathione and increased systemic and renal markers of nitro-oxidative stress (Nitrotyrosine). Allo ameliorated GFR, renal blood flow (RBF), renal vascular resistance and arterial lactate levels. In addition, Allo was associated with increased serum glutathione as well as reduced levels of plasma and renal Nitrotyrosine. Our data show that Allo attenuated BJ-associated AKI, reduced oxidative stress, improved renal hemodynamics and organ perfusion. It might represent a novel adjuvant approach for Bothrops envenomation, a new use for an old and widely available drug. PMID:29155815

Moment-to-moment characteristics of the relationship between arterial pressure and renal interstitial hydrostatic pressure.

PubMed

Komolova, Marina; Adams, Michael A

2010-10-01

The kidney is a key controller of the long-term level of arterial pressure, in part through pressure-natriuresis. Although direct coupling of changes in renal arterial pressure to renal interstitial hydrostatic pressure (RIHP) and consequent sodium excretion is well established, few studies have characterized the moment-to-moment aspects of this process. These studies characterized the short-term hemodynamic component of pressure-natriuresis in vivo before and after autonomic nervous system and renin-angiotensin system inhibition. Changes in RIHP were determined over a range of renal arterial pressures in Wistar rats receiving no treatment, a ganglionic blocker (hexamethonium; 20 mg/kg per hour IV), or an angiotensin II type 1 receptor blocker (losartan; 10 mg/kg per hour IV). After a series of changes in renal arterial pressure, a delay of only ≈1 second was found for the onset of RIHP responses that was independent of the stimulus magnitude and neurohumoral manipulation; however, completion of the full RIHP response was within ≈15 seconds for renal arterial pressure changes of ≤30 mm Hg. The overall slope of the renal arterial pressure- RIHP relationship (0.09±0.01) was also not affected by autonomic nervous system and renin-angiotensin system inhibition despite decreasing renal arterial pressure (↓40% and ↓28%, respectively). Separate assessment of this relationship above and below the prevailing arterial pressure revealed that the pressor versus the depressor portion was blunted (P<0.001), a difference that was abolished after autonomic nervous system and renin-angiotensin system inhibition. The results suggest that spontaneous changes in arterial pressure are coupled to moment-to-moment changes in RIHP over a wide range of pressures, emphasizing a likely role for the dynamic component of the renal arterial pressure-RIHP relationship in the modulation of sodium excretion and, hence, arterial pressure.

Lightning Burns and Electrical Trauma in a Couple Simultaneously Struck by Lightning

PubMed Central

Eyerly-Webb, Stephanie A.; Solomon, Rachele; Lee, Seong K.; Sanchez, Rafael; Carrillo, Eddy H.; Davare, Dafney L.; Kiffin, Chauniqua; Rosenthal, Andrew

2017-01-01

More people are struck and killed by lightning each year in Florida than any other state in the United States. This report discusses a couple that was simultaneously struck by lightning while walking arm-in-arm. Both patients presented with characteristic lightning burns and were admitted for hemodynamic monitoring, serum labs, and observation and were subsequently discharged home. Despite the superficial appearance of lightning burns, serious internal electrical injuries are common. Therefore, lightning strike victims should be admitted and evaluated for cardiac arrhythmias, renal injury, and neurological sequelae.

Unloading therapy by intravenous diuretic in chronic heart failure: a double-edged weapon?

PubMed

De Vecchis, Renato; Ciccarelli, Antonio; Pucciarelli, Armando

2010-08-01

A well established part of therapeutic approaches applying to cases of chronic heart failure (CHF) with extreme fluid retention is represented by intensive intravenous (i.v.) therapy with loop diuretics. This kind of therapy, if appropriately modulated according to the individual clinical picture and biohumoral pattern, is able to decrease the abnormally high ventricular filling pressures, thereby relieving the breathlessness while being able to retrieve a suitable urine output, so as to propitiate regression or disappearance of edema without unfavorable influences on renal clearance of nitrogenous compounds. Nevertheless, the intensive i.v. diuretic therapy should be tailored on the basis of a close assessment of baseline hemodynamic data and hemodynamic response to the medications, in addition to the careful diuretic dose titration and cautious evaluation of risk/benefit ratio. Actually, by using this kind of therapy, there is a risk that a tubular or glomerular injury can be generated and that a frequently preexisting renal dysfunction can be aggravated, especially when excessive doses of loop diuretics are being erroneously administered, so as to cause hypotension, hypoperfusion and/or relative dehydration in patients with decompensated CHF who could have expressly benefitted from intensive unloading therapy. Recently, the genesis of CHF-related progressive renal deterioration has been highlighted by affirming that a major role may be played rather by neurovegetative disorders, that is, by increase in sympathetic tone and abnormalities in kidney's vasomotility than by cardiac inotropism deficiency. The measures, thought to be able to prevent renal arterial constriction and to impede deterioration of glomerular filtration rate (GFR) due to the ischemic-necrotic tubular injury, as occurring in the set of intensive unloading therapy with i.v. furosemide or other loop diuretic, are represented by application of inotropic and renal vasodilator support by dopamine i.v. infusion at low doses or by other inotropic agents provided with recognized renal vasodilator properties and/or by addition to i.v. furosemide of osmotic agents able to expand the hematic volume, so counteracting or minimizing the reflex renal vasoconstriction induced by furosemide-related reduction in intravascular circulating volume: i.v. infusion of small volumes of hypertonic saline solution, as well as administration of albumin, mannitol and/or plasma expanders. Because renal impairment, as developing in the setting of CHF, has proven to represent a very important indicator of adverse outcome, every effort should be addressed to prevent any significant (>25% of basal value) rise in serum creatinine consequent to diuretic unloading therapy or to other procedures (paracentesis of tense ascites, ultrafiltration) aimed at rapid fluid removal in edematous or ascitic CHF or cardiogenetic anasarca. Ultrafiltration, even though a promising technique highly valued for its acknowledged property to obtain a more rapid fluid and weight loss in CHF patients with marked fluid retention, has been demonstrated so far to produce neurohumoral activation, creatinine abnormalities and symptomatic hypotensions similar to those due to i.v. loop diuretics; thus, the hypothesized advantages of this technique remain to be further clarified and confirmed, with regard to its safety profile and cost-effectiveness.

Inappropriate Prescription and Renal Function Among Older Patients with Cognitive Impairment.

PubMed

Sönnerstam, Eva; Sjölander, Maria; Gustafsson, Maria

2016-12-01

Older people are more sensitive to drugs and adverse drug reactions than younger people because of age-related physiological changes such as impaired renal function. As people with dementia are particularly vulnerable to the effects of drugs, it is especially important to evaluate the dosages of renally cleared medications in this group. The aim of this study was to estimate the prevalence of impaired renal function and inappropriate prescriptions on the basis of renal function among older patients with dementia or cognitive impairment. The medical records of 428 patients aged ≥65 years who were admitted to two hospitals in northern Sweden were reviewed and renally cleared medications were identified. The Cockcroft-Gault equation was used to evaluate renal function. Doses were evaluated according to the Geriatric Dosage Handbook. Renal function was impaired (estimated glomerular filtration rate <60 ml/min) in 65.4 % of the study population. Impaired renal function was associated with increasing age. Among 547 prescriptions identified as renally cleared medications, 9.1 % were inappropriate based on the patient's renal function; 13.5 % of the 326 patients prescribed renally cleared medications had inappropriate prescriptions. Inappropriate prescriptions were more common among patients living in nursing homes. Impaired renal function is common and inappropriate prescription is prevalent among old people with cognitive impairment in northern Sweden. Continuous consideration of renal function is important when prescribing medications to this group.

Association among SNAP-25 Gene "Dd"eI and "Mnl"I Polymorphisms and Hemodynamic Changes during Methylphenidate Use: A Functional Near-Infrared Spectroscopy Study

ERIC Educational Resources Information Center

Oner, Ozgur; Akin, Ata; Herken, Hasan; Erdal, Mehmet Emin; Ciftci, Koray; Ay, Mustafa Ertan; Bicer, Duygu; Oncu, Bedriye; Bozkurt, Ozlem Hekim; Munir, Kerim; Yazgan, Yanki

2011-01-01

Objective: To investigate the interaction of treatment-related hemodynamic changes with genotype status for Synaptosomal associated protein 25 (SNAP-25) gene in participants with attention deficit hyperactivity disorder (ADHD) on and off single dose short-acting methylphenidate treatment with functional near-infrared spectroscopy (fNIRS). Method:…

Influence of the rate of infusion on cyclosporine nephrotoxicity in the rat.

PubMed

Finn, W F; McCormack, A J; Sullivan, B A; Hak, L J; Clark, R L

1989-01-01

The effect of the rate of infusion of single and multiple doses of cyclosporine (CsA) on renal function was evaluated in Sprague-Dawley rats. CsA was dissolved in cremophore (Crem) or Tween 80 (Tween) and infused over consecutive 10-min periods at doses of 10, 20, 30 and 40 mg/kg. CsA-Crem and CsA-Tween produced similar and progressive changes in MAP, RBF, and RVR. By the end of the infusion, the mean values (% of control) of MAP (122 +/- 16% and 131 +/- 22%), RBF (56 +/- 11% and 66 +/- 20%), and RVR (222 +/- 38% and 232 +/- 134%) were significantly different from their respective preinfusion values. Infusion of Crem alone resulted in renal vasodilation at low doses and renal vasoconstriction at high doses. Vasoconstriction was not produced by infusion of Tween alone. In addition, animals were treated with vehicle alone (Gp 1), CsA 10 mg/kg/day by injection (Gp 2), or CsA 20 mg/kg/day by i.v. infusion over 4 hr (Gp 3), and were studied at 1 week. Systemic toxicity was greater with the 4-hr infusion as judged by an increase in MAP. The mean values of MAP were 107 +/- 8 (Gp 1), 101 +/- 13 (Gp 2), and 135 +/- 5 mm Hg (Gp 3; p less than 0.05). However, renal function was less severely affected with the 4-hr infusion. The mean values of CIn were 434 +/- 99 (Gp 1), 298 +/- 101 (Gp 2; p less than 0.05), and 425 +/- 114 microL/min/100 g BW (Gp 3); and the mean values for RBF were 2.72 +/- 0.74 (Gp 1), 2.08 +/- 0.17 (Gp 2; p less than 0.05), and 3.35 +/- 0.61 mL/min/100 g BW (Gp 3), respectively. Microangiograms showed marked abnormalities in the intrarenal perfusion pattern in the rats injected with CsA, 10 mg/kg BW. In rats infused over 4 hr with CsA, 20 mg/kg BW, the microangiographic pattern was normal. These studies demonstrate that the acute hemodynamic effects of CsA are directly related to the rate of infusion. Furthermore, the renal toxicity which follows repetitive injection of CsA can be minimized or avoided by administering CsA as a slow infusion. In addition to the total dose administered, the rate of infusion is an important determinant of nephrotoxicity.

Hemodynamic responses to etomidate versus ketamine-thiopental sodium combination for anesthetic induction in coronary artery bypass graft surgery patients with low ejection fraction: a double-blind, randomized, clinical trial.

PubMed

Habibi, Mohammad Reza; Baradari, Afshin Gholipour; Soleimani, Aria; Emami Zeydi, Amir; Nia, Hamid Sharif; Habibi, Ali; Onagh, Naser

2014-10-01

During induction of anesthesia and intubation, hemodynamic changes are very important; especially in patients with coronary artery disease (CAD) and left ventricular dysfunction. A little information is available on the hemodynamic effects of a combination of ketamine-thiopental for induction of anesthesia in patients undergoing coronary artery bypass graft (CABG) surgery, with impaired ventricular function. The aim of this study was to compare the hemodynamic responses to etomidate versus ketamine-thiopental sodium combination for anesthetic induction in CABG surgery patients with low ejection fraction (EF<45%). In a double blind randomized clinical trial, a total of 100 patients, scheduled for elective CABG surgery were randomly assigned into two groups. These patients received either etomidate or ketamine-thiopental sodium combination at induction of anesthesia. Hemodynamics variable were measured and recorded at baseline, immediately before and after laryngoscopy and intubation, one, two and three minutes after intubation. Also, muscle twitching incidence among patients in two groups was evaluated. No significant differences between the two groups regarding the changes of hemodynamic variables including systolic and diastolic arterial blood pressure, mean arterial pressure and heart rate, were notice (p>0.05). Muscle twitching was not observed in the two groups. Hemodynamic stability after administration of ketamine-thiopental sodium combination for induction of anesthesia in patients undergoing CABG surgery, with impaired ventricular function, supports the clinical impression that this combination is safe in CABG surgery patients with low EF.

Monitoring hemodynamics and oxygenation of the kidney in rats by a combined near-infrared spectroscopy and invasive probe approach

NASA Astrophysics Data System (ADS)

Grosenick, Dirk; Cantow, Kathleen; Arakelyan, Karen; Wabnitz, Heidrun; Flemming, Bert; Skalweit, Angela; Ladwig, Mechthild; Macdonald, Rainer; Niendorf, Thoralf; Seeliger, Erdmann

2015-07-01

We have developed a hybrid approach to investigate the dynamics of perfusion and oxygenation in the kidney of rats under pathophysiologically relevant conditions. Our approach combines near-infrared spectroscopy to quantify hemoglobin concentration and oxygen saturation in the renal cortex, and an invasive probe method for measuring total renal blood flow by an ultrasonic probe, perfusion by laser-Doppler fluxmetry, and tissue oxygen tension via fluorescence quenching. Hemoglobin concentration and oxygen saturation were determined from experimental data by a Monte Carlo model. The hybrid approach was applied to investigate and compare temporal changes during several types of interventions such as arterial and venous occlusions, as well as hyperoxia, hypoxia and hypercapnia induced by different mixtures of the inspired gas. The approach was also applied to study the effects of the x-ray contrast medium iodixanol on the kidney.

Clinical application of calculated split renal volume using computed tomography-based renal volumetry after partial nephrectomy: Correlation with technetium-99m dimercaptosuccinic acid renal scan data.

PubMed

Lee, Chan Ho; Park, Young Joo; Ku, Ja Yoon; Ha, Hong Koo

2017-06-01

To evaluate the clinical application of computed tomography-based measurement of renal cortical volume and split renal volume as a single tool to assess the anatomy and renal function in patients with renal tumors before and after partial nephrectomy, and to compare the findings with technetium-99m dimercaptosuccinic acid renal scan. The data of 51 patients with a unilateral renal tumor managed by partial nephrectomy were retrospectively analyzed. The renal cortical volume of tumor-bearing and contralateral kidneys was measured using ImageJ software. Split estimated glomerular filtration rate and split renal volume calculated using this renal cortical volume were compared with the split renal function measured with technetium-99m dimercaptosuccinic acid renal scan. A strong correlation between split renal function and split renal volume of the tumor-bearing kidney was observed before and after surgery (r = 0.89, P < 0.001 and r = 0.94, P < 0.001). The preoperative and postoperative split estimated glomerular filtration rate of the operated kidney showed a moderate correlation with split renal function (r = 0.39, P = 0.004 and r = 0.49, P < 0.001). The correlation between reductions in split renal function and split renal volume of the operated kidney (r = 0.87, P < 0.001) was stronger than that between split renal function and percent reduction in split estimated glomerular filtration rate (r = 0.64, P < 0.001). The split renal volume calculated using computed tomography-based renal volumetry had a strong correlation with the split renal function measured using technetium-99m dimercaptosuccinic acid renal scan. Computed tomography-based split renal volume measurement before and after partial nephrectomy can be used as a single modality for anatomical and functional assessment of the tumor-bearing kidney. © 2017 The Japanese Urological Association.

Social cognition and prefrontal hemodynamic responses during a working memory task in schizophrenia.

PubMed

Pu, Shenghong; Nakagome, Kazuyuki; Yamada, Takeshi; Itakura, Masashi; Yamanashi, Takehiko; Yamada, Sayaka; Masai, Mieko; Miura, Akihiko; Yamauchi, Takahira; Satake, Takahiro; Iwata, Masaaki; Nagata, Izumi; Roberts, David L; Kaneko, Koichi

2016-03-01

Social cognition is an important determinant of functional impairment in schizophrenia, but its relationship with the prefrontal functional abnormalities associated with the condition is still unclear. The present study aimed to explore the relationship between social cognition and prefrontal function in patients with schizophrenia using 52-channel near-infrared spectroscopy (NIRS). Twenty-six patients with schizophrenia and 26 age-, gender-, and intelligence quotient-matched healthy controls (HCs) participated in the study. Hemodynamic responses in the prefrontal and superior temporal cortical regions were assessed during a working memory task using NIRS. Social cognition was assessed using the Social Cognition Screening Questionnaire (SCSQ). The observed hemodynamic responses were significantly reduced in the lateral prefrontal cortex (PFC), the frontopolar cortex, and temporal regions in subjects with schizophrenia compared to HCs. Additionally, lateral PFC hemodynamic responses assessed during the working memory task demonstrated a strong positive correlation with the SCSQ theory of mind (ToM) subscale score even after controlling for working memory performance. These results suggest that ToM integrity is closely related to lateral PFC functional abnormalities found in patients with schizophrenia. In addition, this study provides evidence to suggest that NIRS could be used to identify biomarkers of social cognition function in subjects with schizophrenia.

Use of Aminocaproic Acid in Combination With Extracorporeal Membrane Oxygenation in a Case of Leptospirosis Pulmonary Hemorrhage Syndrome.

PubMed

Pardinas, Miguel; Mendirichaga, Rodrigo; Budhrani, Gaurav; Garg, Rajan; Rosario, Luis; Rico, Rene; Panos, Anthony; Baier, Horst; Krick, Stefanie

2017-01-01

A 32-year-old man presented with a 10-day history of fever, chills, nausea, vomiting, myalgia, nonproductive cough, and worsening dyspnea after freshwater swimming in the Caribbean 1 week prior to presentation. Shortly after arrival at the hospital, the patient developed severe respiratory distress with massive hemoptysis. Based on serologic workup, he was diagnosed with leptospirosis pulmonary hemorrhage syndrome leading to diffuse alveolar hemorrhage, severe hypoxemic respiratory failure, and multiorgan failure. He received appropriate antibiotic coverage along with hemodynamic support with norepinephrine and vasopressin, mechanical ventilation, and renal replacement therapy in an intensive care unit. Introduction of extracorporeal membrane oxygenation was initiated to provide lung-protective ventilation supporting the recovery of his pulmonary function. Aminocaproic acid was used to stop and prevent further alveolar hemorrhage. He fully recovered thereafter; however, it is uncertain whether it was the use of aminocaproic acid that led to the resolution of his disease.

Use of Aminocaproic Acid in Combination With Extracorporeal Membrane Oxygenation in a Case of Leptospirosis Pulmonary Hemorrhage Syndrome

PubMed Central

Pardinas, Miguel; Mendirichaga, Rodrigo; Budhrani, Gaurav; Garg, Rajan; Rosario, Luis; Rico, Rene; Panos, Anthony; Baier, Horst; Krick, Stefanie

2017-01-01

A 32-year-old man presented with a 10-day history of fever, chills, nausea, vomiting, myalgia, nonproductive cough, and worsening dyspnea after freshwater swimming in the Caribbean 1 week prior to presentation. Shortly after arrival at the hospital, the patient developed severe respiratory distress with massive hemoptysis. Based on serologic workup, he was diagnosed with leptospirosis pulmonary hemorrhage syndrome leading to diffuse alveolar hemorrhage, severe hypoxemic respiratory failure, and multiorgan failure. He received appropriate antibiotic coverage along with hemodynamic support with norepinephrine and vasopressin, mechanical ventilation, and renal replacement therapy in an intensive care unit. Introduction of extracorporeal membrane oxygenation was initiated to provide lung-protective ventilation supporting the recovery of his pulmonary function. Aminocaproic acid was used to stop and prevent further alveolar hemorrhage. He fully recovered thereafter; however, it is uncertain whether it was the use of aminocaproic acid that led to the resolution of his disease. PMID:28469503

Management of abdominal compartment syndrome after transurethral resection of the prostate.

PubMed

Gaut, Megan M; Ortiz, Jaime

2015-01-01

Acute abdominal compartment syndrome is most commonly associated with blunt abdominal trauma, although it has been seen after ruptured abdominal aortic aneurysm, liver transplantation, pancreatitis, and massive volume resuscitation. Acute abdominal compartment syndrome develops once the intra-abdominal pressure increases to 20-25 mmHg and is characterized by an increase in airway pressures, inadequate ventilation and oxygenation, altered renal function, and hemodynamic instability. This case report details the development of acute abdominal compartment syndrome during transurethral resection of the prostate with extra- and intraperitoneal bladder rupture under general anesthesia. The first signs of acute abdominal compartment syndrome in this patient were high peak airway pressures and difficulty delivering tidal volumes. Management of the compartment syndrome included re-intubation, emergent exploratory laparotomy, and drainage of irrigation fluid. Difficulty with ventilation should alert the anesthesiologist to consider abdominal compartment syndrome high in the list of differential diagnoses during any endoscopic bladder or bowel case. Copyright © 2013 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

[Management of abdominal compartment syndrome after transurethral resection of the prostate].

PubMed

Gaut, Megan M; Ortiz, Jaime

2015-01-01

Acute abdominal compartment syndrome is most commonly associated with blunt abdominal trauma, although it has been seen after ruptured abdominal aortic aneurysm, liver transplantation, pancreatitis, and massive volume resuscitation. Acute abdominal compartment syndrome develops once the intra-abdominal pressure increases to 20-25mmHg and is characterized by an increase in airway pressures, inadequate ventilation and oxygenation, altered renal function, and hemodynamic instability. This case report details the development of acute abdominal compartment syndrome during transurethral resection of the prostate with extra- and intraperitoneal bladder rupture under general anesthesia. The first signs of acute abdominal compartment syndrome in this patient were high peak airway pressures and difficulty delivering tidal volumes. Management of the compartment syndrome included re-intubation, emergent exploratory laparotomy, and drainage of irrigation fluid. Difficulty with ventilation should alert the anesthesiologist to consider abdominal compartment syndrome high in the list of differential diagnoses during any endoscopic bladder or bowel case. Copyright © 2013 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Dynamic analysis of patterns of renal sympathetic nerve activity: implications for renal function.

PubMed

DiBona, Gerald F

2005-03-01

Methods of dynamic analysis are used to provide additional understanding of the renal sympathetic neural control of renal function. The concept of functionally specific subgroups of renal sympathetic nerve fibres conveying information encoded in the frequency domain is presented. Analog pulse modulation and pseudorandom binary sequence stimulation patterns are used for the determination of renal vascular frequency response. Transfer function analysis is used to determine the effects of non-renal vasoconstrictor and vasoconstrictor intensities of renal sympathetic nerve activity on dynamic autoregulation of renal blood flow.

Predictors of Recoverability of Renal Function after Pyeloplasty in Adults with Ureteropelvic Junction Obstruction.

PubMed

Li, Xiao-Dong; Wu, Yu-Peng; Wei, Yong; Chen, Shao-Hao; Zheng, Qing-Shui; Cai, Hai; Xue, Xue-Yi; Xu, Ning

2018-01-01

This study aimed to identify factors predicting the recoverability of renal function after pyeloplasty in adult patients with ureteropelvic junction obstruction. We retrospectively reviewed 138 adults with unilateral renal obstruction-induced hydronephrosis and who underwent Anderson-Hynes dismembered pyeloplasty from January 2013 to January 2016. Hydronephrosis was classified preoperatively according to the Society for Fetal Urology (SFU) grading system. All patients underwent Doppler ultrasonography, excretory urography, computed tomography, and technetium-99m-diethylenetriamine pentaacetic acid radioisotope (99mTc DTPA) renography before and after surgery. Renal resistive index (RRI) and 99mTc DTPA renography were repeated at 1, 3, 6, and 12 months. Multivariate analysis identified age, renal pelvic type, SFU grade, preoperative RRI, decline of RRI, and renal parenchyma to hydronephrosis area ratio (PHAR) as independent predictors of renal function recoverability after pyeloplasty. However, preoperative RRI and RRI decline were not significantly associated with recoverability of renal function in patients aged >35 years. Lower preoperative RRI, greater decline in RRI, higher PHAR, lower SFU grade, and extrarenal pelvis were associated with greater improvements in postoperative renal function. Preoperative differential renal function cannot independently predict the recoverability of postoperative renal function in adult patients with unilateral renal obstruction-induced hydronephrosis. SFU grade, renal pelvic type, PHAR, preoperative RRI, and decline in RRI were significantly associated with the recoverability of renal function in adult patients aged <35 years, while only SFU grade, renal pelvic type, and PHAR were significantly associated with renal function recoverability in patients aged ≥35 years. Renal function recovery was better in patients younger than 35 years when compared with older patients. © 2018 S. Karger AG, Basel.

Renal dopamine containing nerves. What is their functional significance?

PubMed

DiBona, G F

1990-06-01

Biochemical and morphological studies indicate that there are nerves within the kidney that contain dopamine and that various structures within the kidney contain dopamine receptors. However, the functional significance of these renal dopamine containing nerves in relation to renal dopamine receptors is unknown. The functional significance could be defined by demonstrating that an alteration in one or more renal functions occurring in response to reflex or electrical activation of efferent renal nerves is dependent on release of dopamine as the neurotransmitter from the renal nerve terminals acting on renal dopamine receptors. Thus, the hypothesis becomes: reflex or electrical activation of efferent renal nerves causes alterations in renal function (eg, renal blood flow, water and solute handling) that are inhibited by specific and selective dopamine receptor antagonists. As reviewed herein, the published experimental data do not support the hypothesis. Therefore, the view that alterations in one or more renal functions occurring in response to reflex or electrical activation of efferent renal nerves are dependent on release of dopamine as the neurotransmitter from the renal nerve terminals acting on renal dopamine receptors remains unproven.

Gender characteristics of cerebral hemodynamics during complex cognitive functioning.

PubMed

Misteli, Maria; Duschek, Stefan; Richter, André; Grimm, Simone; Rezk, Markus; Kraehenmann, Rainer; Boeker, Heinz; Seifritz, Erich; Schuepbach, Daniel

2011-06-01

Functional Transcranial Doppler sonography (fTCD) has been applied to assess peak mean cerebral blood flow velocity (MFV) with a high temporal resolution during cognitive activation. Yet, little attention has been devoted to gender-related alterations of MFV, including spectral analysis. In healthy subjects, fTCD was used to investigate a series of cerebral hemodynamic parameters in the middle cerebral arteries (MCA) during the Trail Making Tests (TMT), a means of selective attention and complex cognitive functioning. In females, there was a frequency peak at 0.375 Hz in both MCA, and we observed a dynamic shift in hemispheric dominance during that condition. Further, after the start phase, there was an MFV decline during complex functioning for the entire sample. These novel results suggest condition-specific features of cerebral hemodynamics in females, and it adds to the notion that gender is a fundamental confounder of brain physiology. Copyright © 2011 Elsevier Inc. All rights reserved.

Effects of Obesity on Cardiovascular Hemodynamics, Cardiac Morphology, and Ventricular Function.

PubMed

Alpert, Martin A; Omran, Jad; Bostick, Brian P

2016-12-01

Obesity produces a variety of hemodynamic alterations that may cause changes in cardiac morphology which predispose to left and right ventricular dysfunction. Various neurohormonal and metabolic alterations commonly associated with obesity may contribute to these abnormalities of cardiac structure and function. These changes in cardiovascular hemodynamics, cardiac morphology, and ventricular function may, in severely obese patients, predispose to heart failure, even in the absence of other forms of heart disease (obesity cardiomyopathy). In normotensive obese patients, cardiac involvement is commonly characterized by elevated cardiac output, low peripheral vascular resistance, and increased left ventricular (LV) end-diastolic pressure. Sleep-disordered breathing may lead to pulmonary arterial hypertension and, in association with left heart failure, may contribute to elevation of right heart pressures. These alterations, in association with various neurohormonal and metabolic abnormalities, may produce LV hypertrophy; impaired LV diastolic function; and less commonly, LV systolic dysfunction. Many of these alterations are reversible with substantial voluntary weight loss.

Effect of a Flared Renal Stent on the Performance of Fenestrated Stent-Grafts at Rest and Exercise Conditions.

PubMed

Kandail, Harkamaljot; Hamady, Mohamad; Xu, Xiao Yun

2016-10-01

To quantify the hemodynamic impact of a flared renal stent on the performance of fenestrated stent-grafts (FSGs) by analyzing flow patterns and wall shear stress-derived parameters in flared and nonflared FSGs in different physiologic scenarios. Hypothetical models of FSGs were created with and without flaring of the proximal portion of the renal stent. Flared FSGs with different dilation angles and protrusion lengths were examined, as well as a nonplanar flared FSG to account for lumbar curvature. Laminar and pulsatile blood flow was simulated by numerically solving Navier-Stokes equations. A physiologically realistic flow rate waveform was prescribed at the inlet, while downstream vasculature was modeled using a lumped parameter 3-element windkessel model. No slip boundary conditions were imposed at the FSG walls, which were assumed to be rigid. While resting simulations were performed on all the FSGs, exercise simulations were also performed on a flared FSG to quantify the effect of flaring in different physiologic scenarios. For cycle-averaged inflow of 2.94 L/min (rest) and 4.63 L/min (exercise), 27% of blood flow was channeled into each renal branch at rest and 21% under exercise for all the flared FSGs examined. Although the renal flow waveform was not affected by flaring, flow within the flared FSGs was disturbed. This flow disturbance led to high endothelial cell activation potential (ECAP) values at the renal ostia for all the flared geometries. Reducing the dilation angle or protrusion length and exercise lowered the ECAP values for flared FSGs. Flaring of renal stents has a negligible effect on the time dependence of renal flow rate waveforms and can maintain sufficient renal perfusion at rest and exercise. Local flow patterns are, however, strongly dependent on renal flaring, which creates a local flow disturbance and may increase the thrombogenicity at the renal ostia. Smaller dilation angles, shorter protrusion lengths, and moderate lower limb exercise are likely to reduce the risk of thrombosis in flared geometries. © The Author(s) 2016.

Association between pulmonary function and renal function: findings from China and Australia.

PubMed

Yu, Dahai; Chen, Tao; Cai, Yamei; Zhao, Zhanzheng; Simmons, David

2017-05-01

The relationship between obstructive lung function and impaired renal function is unclear. This study investigated the dose-response relationship between obstructive lung function and impaired renal function. Two independent cross-sectional studies with representative sampling were applied. 1454 adults from rural Victoria, Australia (1298 with normal renal function, 156 with impaired renal function) and 5824 adults from Nanjing, China (4313 with normal renal function, 1511 with impaired renal function). Pulmonary function measurements included forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Estimated glomerular filtration rate (eGFR), and impaired renal function marked by eGFR <60 mL/min/1.73m 2 were used as outcome. eGFR increased linearly with FEV1 in Chinese participants and with FVC in Australians. A non-linear relationship with peaked eGFR was found for FEV1 at 2.65 L among Australians and for FVC at 2.78 L among Chinese participants, respectively. A non-linear relationship with peaked eGFR was found for the predicted percentage value of forced expiratory volume in 1 s (PFEV1) at 81-82% and for the predicted percentage value of forced vital capacity (PFVC) at 83-84% among both Chinese and Australian participants, respectively. The non-linear dose-response relationships between lung capacity measurements (both for FEV1 and FVC) and risk of impaired renal function were consistently identified in both Chinese and Australian participants. An increased risk of impaired renal function was found below 3.05 L both for FEV1 and FVC, respectively. The non-linear relationship between PFEV and PVC and the risk of impaired renal function were consistently identified in both Chinese and Australian participants. An increased risk of impaired renal function was found below 76-77% for PFEV1 and 79-80% for PFVC, respectively. In both Australian and Chinese populations, the risk of impaired renal function increased both with FEV1 and FVC below 3.05 L, with PFEV1 below 76-77% or with PFVC below 79-80%, respectively. Obstructive lung function was associated with increased risk of reduced renal function. The screen for impaired renal function in patients with obstructive lung disease might be useful to ensure there was no impaired renal function before the commencement of potentially nephrotoxic medication where indicated (eg diuretics).

ShockOmics: multiscale approach to the identification of molecular biomarkers in acute heart failure induced by shock.

PubMed

Aletti, Federico; Conti, Costanza; Ferrario, Manuela; Ribas, Vicent; Bollen Pinto, Bernardo; Herpain, Antoine; Post, Emiel; Romay Medina, Eduardo; Barlassina, Cristina; de Oliveira, Eliandre; Pastorelli, Roberta; Tedeschi, Gabriella; Ristagno, Giuseppe; Taccone, Fabio S; Schmid-Schönbein, Geert W; Ferrer, Ricard; De Backer, Daniel; Bendjelid, Karim; Baselli, Giuseppe

2016-01-28

The ShockOmics study (ClinicalTrials.gov identifier NCT02141607) is a multicenter prospective observational trial aimed at identifying new biomarkers of acute heart failure in circulatory shock, by means of a multiscale analysis of blood samples and hemodynamic data from subjects with circulatory shock. Ninety septic shock and cardiogenic shock patients will be recruited in three intensive care units (ICU) (Hôpital Erasme, Université Libre de Bruxelles, Belgium; Hospital Universitari Mutua Terrassa, Spain; Hôpitaux Universitaires de Genève, Switzerland). Hemodynamic signals will be recorded every day for up to seven days from shock diagnosis (time T0). Clinical data and blood samples will be collected for analysis at: i) T1 < 16 h from T0; ii) T2 = 48 h after T0; iii) T3 = day 7 or before discharge or before discontinuation of therapy in case of fatal outcome; iv) T4 = day 100. The inclusion criteria are: shock, Sequential Organ Failure Assessment (SOFA) score > 5 and lactate levels ≥ 2 mmol/L. The exclusion criteria are: expected death within 24 h since ICU admission; > 4 units of red blood cells or >1 fresh frozen plasma transfused; active hematological malignancy; metastatic cancer; chronic immunodepression; pre-existing end stage renal disease requiring renal replacement therapy; recent cardiac surgery; Child-Pugh C cirrhosis; terminal illness. Enrollment will be preceded by the signature of the Informed Consent by the patient or his/her relatives and by the physician in charge. Three non-shock control groups will be included in the study: a) healthy blood donors (n = 5); b) septic patients (n = 10); c) acute myocardial infarction or patients with prolonged acute arrhythmia (n = 10). The hemodynamic data will be downloaded from the ICU monitors by means of dedicated software. The blood samples will be utilized for transcriptomics, proteomics and metabolomics ("-omics") analyses. ShockOmics will provide new insights into the pathophysiological mechanisms underlying shock as well as new biomarkers for the timely diagnosis of cardiac dysfunction in shock and quantitative indices for assisting the therapeutic management of shock patients.

Echocardiography-based hemodynamic management of left ventricular diastolic dysfunction: a feasibility and safety study.

PubMed

Shillcutt, Sasha K; Montzingo, Candice R; Agrawal, Ankit; Khaleel, Maseeha S; Therrien, Stacey L; Thomas, Walker R; Porter, Thomas R; Brakke, Tara R

2014-11-01

Patients with left ventricular diastolic dysfunction (LVDD) are at increased risk of postoperative adverse events. The primary aim of this study was to evaluate the safety and feasibility of using echocardiography-guided hemodynamic management (EGHEM) during surgery in subjects with LVDD compared to conventional management. The feasibility of using echocardiography to direct a treatment algorithm and clinical outcomes were compared for safety between groups. Subjects were screened for LVDD by preoperative transthoracic echocardiography (TTE) and randomized to the conventional or EGHEM group. Subjects in EGHEM received hemodynamic management based on left ventricular filling patterns on transesophageal echocardiography (TEE). Primary outcomes measured were the feasibility to obtain TEE images and follow a TEE-based treatment algorithm. Safety outcomes also compared the following clinical differences between groups: length of hospitalization, incidence of atrial fibrillation, congestive heart failure (CHF), myocardial infarction, cerebrovascular accident, transient ischemic attack and renal failure measured 30 days postoperatively. Population consisted of 28 surgical subjects (14 in conventional group and 14 in EGHEM group). Mean subject age was 73.4 ± 6.7 years (36% male) in conventional group and 65.9 ± 14.4 years (36% male) in EGHEM group. Procedures included orthopedic (conventional = 29%, EGHEM 36%), general (conventional = 50%, EGHEM = 36%), vascular (conventional = 7%, EGHEM = 21%), and thoracic (conventional = 14%, EGHEM = 7%). There was no statistically significant difference in adverse clinical events between the 2 groups. The EGHEM group had less CHF, atrial fibrillation, and shorter length of stay. Echocardiography-guided hemodynamic management of patients with LVDD during surgery is feasible and may be a safe alternative to conventional management. © 2014, Wiley Periodicals, Inc.

Visceral Congestion in Heart Failure: Right Ventricular Dysfunction, Splanchnic Hemodynamics, and the Intestinal Microenvironment.

PubMed

Polsinelli, Vincenzo B; Sinha, Arjun; Shah, Sanjiv J

2017-12-01

Visceral venous congestion of the gut may play a key role in the pathogenesis of right-sided heart failure (HF) and cardiorenal syndromes. Here, we review the role of right ventricular (RV) dysfunction, visceral congestion, splanchnic hemodynamics, and the intestinal microenvironment in the setting of right-sided HF. We review recent literature on this topic, outline possible mechanisms of disease pathogenesis, and discuss potential therapeutics. There are several mechanisms linking RV-gut interactions via visceral venous congestion which could result in (1) hypoxia and acidosis in enterocytes, which may lead to enhanced sodium-hydrogen exchanger 3 (NHE3) expression with increased sodium and fluid retention; (2) decreased luminal pH in the intestines, which could lead to alteration of the gut microbiome which could increase gut permeability and inflammation; (3) alteration of renal hemodynamics with triggering of the cardiorenal syndrome; and (4) altered phosphate metabolism resulting in increased pulmonary artery stiffening, thereby increasing RV afterload. A wide variety of therapeutic interventions that act on the RV, pulmonary vasculature, intestinal microenvironment, and the kidney could alter these pathways and should be tested in patients with right-sided HF. The RV-gut axis is an important aspect of HF pathogenesis that deserves more attention. Modulation of the pathways interconnecting the right heart, visceral congestion, and the intestinal microenvironment could be a novel avenue of intervention for right-sided HF.

Effects of active, passive and motor imagery paradigms on cerebral and peripheral hemodynamics in older volunteers: a functional TCD study.

PubMed

Salinet, Angela S M; Panerai, Ronney B; Robinson, Thompson G

2012-06-01

This study aimed to compare the response of metabolic-induced cerebral hemodynamic changes measured using transcranial Doppler (TCD) ultrasonography during passive, active and motor imagery paradigms, and associated peripheral hemodynamic responses. Continuous recordings of bilateral cerebral blood flow velocity (CBFv), blood pressure, heart rate and end-tidal CO(2) were performed in 12 right-handed subjects (aged ≥45 y) before, during and after 60 s of active, passive and mental-imagined paradigms. The results revealed no significant difference in CBFv responses between the paradigms and, furthermore, the temporal patterns of the hemodynamic responses showed some degree of similarity. Moreover, significant changes were seen in cerebral and peripheral hemodynamic responses for all paradigms. Our results suggest that active, passive and motor imagery paradigms can be used interchangeably to assess hemodynamic responses. This will enable more detailed noninvasive assessment in patients, where voluntary movement is not possible, but where abnormalities of cerebral hemodynamic control mechanisms can be anticipated. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Biomechanical and Hemodynamic Measures of Right Ventricular Diastolic Function: Translating Tissue Biomechanics to Clinical Relevance.

PubMed

Jang, Sae; Vanderpool, Rebecca R; Avazmohammadi, Reza; Lapshin, Eugene; Bachman, Timothy N; Sacks, Michael; Simon, Marc A

2017-09-12

Right ventricular (RV) diastolic function has been associated with outcomes for patients with pulmonary hypertension; however, the relationship between biomechanics and hemodynamics in the right ventricle has not been studied. Rat models of RV pressure overload were obtained via pulmonary artery banding (PAB; control, n=7; PAB, n=5). At 3 weeks after banding, RV hemodynamics were measured using a conductance catheter. Biaxial mechanical properties of the RV free wall myocardium were obtained to extrapolate longitudinal and circumferential elastic modulus in low and high strain regions (E 1 and E 2 , respectively). Hemodynamic analysis revealed significantly increased end-diastolic elastance (E ed ) in PAB (control: 55.1 mm Hg/mL [interquartile range: 44.7-85.4 mm Hg/mL]; PAB: 146.6 mm Hg/mL [interquartile range: 105.8-155.0 mm Hg/mL]; P =0.010). Longitudinal E 1 was increased in PAB (control: 7.2 kPa [interquartile range: 6.7-18.1 kPa]; PAB: 34.2 kPa [interquartile range: 18.1-44.6 kPa]; P =0.018), whereas there were no significant changes in longitudinal E 2 or circumferential E 1 and E 2 . Last, wall stress was calculated from hemodynamic data by modeling the right ventricle as a sphere: stress=Pressure×radius2×thickness. RV pressure overload in PAB rats resulted in an increase in diastolic myocardial stiffness reflected both hemodynamically, by an increase in E ed , and biomechanically, by an increase in longitudinal E 1 . Modest increases in tissue biomechanical stiffness are associated with large increases in E ed . Hemodynamic measurements of RV diastolic function can be used to predict biomechanical changes in the myocardium. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Renal Function Descriptors in Neonates: Which Creatinine-Based Formula Best Describes Vancomycin Clearance?

PubMed

Bhongsatiern, Jiraganya; Stockmann, Chris; Yu, Tian; Constance, Jonathan E; Moorthy, Ganesh; Spigarelli, Michael G; Desai, Pankaj B; Sherwin, Catherine M T

2016-05-01

Growth and maturational changes have been identified as significant covariates in describing variability in clearance of renally excreted drugs such as vancomycin. Because of immaturity of clearance mechanisms, quantification of renal function in neonates is of importance. Several serum creatinine (SCr)-based renal function descriptors have been developed in adults and children, but none are selectively derived for neonates. This review summarizes development of the neonatal kidney and discusses assessment of the renal function regarding estimation of glomerular filtration rate using renal function descriptors. Furthermore, identification of the renal function descriptors that best describe the variability of vancomycin clearance was performed in a sample study of a septic neonatal cohort. Population pharmacokinetic models were developed applying a combination of age-weight, renal function descriptors, or SCr alone. In addition to age and weight, SCr or renal function descriptors significantly reduced variability of vancomycin clearance. The population pharmacokinetic models with Léger and modified Schwartz formulas were selected as the optimal final models, although the other renal function descriptors and SCr provided reasonably good fit to the data, suggesting further evaluation of the final models using external data sets and cross validation. The present study supports incorporation of renal function descriptors in the estimation of vancomycin clearance in neonates. © 2015, The American College of Clinical Pharmacology.

Role of pulmonary hemodynamics in determining 6-minute walk test result in atrial septal defect: an observational study.

PubMed

Supomo, Supomo; Darmawan, Handy; Arjana, Adika Zhulhi

2018-05-22

The presence of altered pulmonary hemodynamics in adult patients with atrial septal defect (ASD) is common. However, there are no observational studies which evaluate the impact of altered pulmonary hemodynamics on the 6-min walk test (6MWT) result. This study aimed to investigate the role of pulmonary hemodynamics in determining 6MWT result of patients with ASD. Forty-six consecutive adult patients with ASD were included in this study. Right heart catheterization was performed to obtain the pulmonary hemodynamics profile. Meanwhile, 6MWT was presented as high or low with cut-off point 350 m. Receiver operating characteristic (ROC) was used for analytical methods. Abnormal functional capacity was indicated by ROC result of mPAP cut-off value of > 24 mmHg (p = 0.0243; AUC = 0.681). The value of PVR > 3.42 woods unit (WU) showed high specificity in determining abnormal functional capacity (p = 0.0069; AUC = 0.713). Flow ratio with cut-off point ≤4.89 had the highest sensitivity (100%) (p = 0.8300; AUC = 0.520). Pulmonary hemodynamics can serve as an indicator of 6MWT result in adult ASD patients with values of mPAP> 24 mmHg and PVR > 3.42 WU.

Arterial hypertension and thyroid disorders: what is important to know in clinical practice?

PubMed

Mazza, A; Beltramello, G; Armigliato, M; Montemurro, D; Zorzan, S; Zuin, M; Rampin, L; Marzola, M C; Grassetto, G; Al-Nahhas, A; Rubello, D

2011-09-01

This review describes the pathogenic mechanisms of blood pressure (BP) regulation and long-term control in thyroid disorders. Variations from the euthyroid status affect virtually all physiological systems but the effects on the cardiovascular system are particularly pronounced. Thyroid disorders induce several hemodynamic changes leading to elevated BP as a consequence of their interaction with endothelial function, vascular reactivity, renal hemodynamic and renin-angiotensin system. However, in thyroid disorders, the regulation of BP and the development and maintenance of variable forms of arterial hypertension (HT) are different. Hyperthyroidism results in an increased endothelium-dependent responsiveness secondary to the shear stress induced by the hyperdynamic circulation, and contributes to reduce vascular resistance. Conversely, hypothyroidism is accompanied by a marked decrease in sensitivity to sympathetic agonists with an increase of peripheral vascular resistance and arterial stiffness. Furthermore in animal models, hypothyroidism reduces the endothelium-dependent and nitric oxide-dependent vasodilatation. HT due to thyroid disorders is usually reversible with achievement of euthyroidism, but in some cases pharmacological treatment for BP control is required. In hyperthyroidism, β-blockers are the first-choice treatment to control BP but when they are contraindicated or not tolerated, ACE-inhibitors or calcium-channel blockers (CCB) are recommended. Hypothyroidism is a typical low rennin HT form showing a better antihypertensive response to CCB and diuretics; indeed in hypothyroidism a low-sodium diet seems further to improve BP control. Randomized clinical trials to compare the efficacy on BP control of the antihypertensive treatment in thyroid disorders are needed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Hemodynamics of Pericardial Aortic Valves: Contemporary Stented versus Stentless Valves in a Matched Comparison

PubMed Central

Holinski, Sebastian; Zhigalov, Konstantin; Zielinski, Christina Barbara; Grubitzsch, Herko

2017-01-01

Purpose: Hemodynamic performance of aortic valve bioprostheses is essential for reliable function and durability. So far, the supra-annularly implanted stentless Sorin Freedom Solo (SFS) demonstrated unsurpassed hemodynamic properties. As contemporary stented and externally mounted pericardial bioprostheses, like the Labcor Dokimos Plus (LDP), also improve hemodynamic performance, these types of valves were compared in this study. Methods: A total of 218 patients, who underwent aortic valve replacement with the LDP or the SFS, were matched retrospectively 1:1 on variables affecting hemodynamic measurements: implanted valve size, age, sex, and body surface area (BSA). With matching tolerance for valve size and gender of 0%, for age and BSA of 5%, 57 patient-pairs were yielded. Operative data, clinical, and hemodynamic outcome were analyzed. Results: Except for slightly higher left ventricular function and lower procedural times in the SFS group, preoperative, operative, and postoperative characteristics of patient-pairs did not differ significantly. Mean pressure gradients, effective orifice areas (EOAs), and indexed EOAs were comparable. Corresponding to valve sizes of 21, 23, 25, and 27 mm, the indexed EOAs of the LDP and SFS prostheses were 1.08 ± 0.33, 0.92 ± 0.19, 0.93 ± 0.24, 0.99 ± 0.13 cm2/m2 and 0.81 ± 0.13, 0.92 ± 0.28, 0.95 ± 0.20, 1.04 ± 0.27 cm2/m2, respectively. Conclusion: Contemporary stented and stentless pericardial bioprostheses showed excellent hemodynamic properties without significant differences in EOAs and indexed EOAs. PMID:28890465

A machine learning approach to identify functional biomarkers in human prefrontal cortex for individuals with traumatic brain injury using functional near-infrared spectroscopy.

PubMed

Karamzadeh, Nader; Amyot, Franck; Kenney, Kimbra; Anderson, Afrouz; Chowdhry, Fatima; Dashtestani, Hadis; Wassermann, Eric M; Chernomordik, Victor; Boccara, Claude; Wegman, Edward; Diaz-Arrastia, Ramon; Gandjbakhche, Amir H

2016-11-01

We have explored the potential prefrontal hemodynamic biomarkers to characterize subjects with Traumatic Brain Injury (TBI) by employing the multivariate machine learning approach and introducing a novel task-related hemodynamic response detection followed by a heuristic search for optimum set of hemodynamic features. To achieve this goal, the hemodynamic response from a group of 31 healthy controls and 30 chronic TBI subjects were recorded as they performed a complexity task. To determine the optimum hemodynamic features, we considered 11 features and their combinations in characterizing TBI subjects. We investigated the significance of the features by utilizing a machine learning classification algorithm to score all the possible combinations of features according to their predictive power. The identified optimum feature elements resulted in classification accuracy, sensitivity, and specificity of 85%, 85%, and 84%, respectively. Classification improvement was achieved for TBI subject classification through feature combination. It signified the major advantage of the multivariate analysis over the commonly used univariate analysis suggesting that the features that are individually irrelevant in characterizing the data may become relevant when used in combination. We also conducted a spatio-temporal classification to identify regions within the prefrontal cortex (PFC) that contribute in distinguishing between TBI and healthy subjects. As expected, Brodmann areas (BA) 10 within the PFC were isolated as the region that healthy subjects (unlike subjects with TBI), showed major hemodynamic activity in response to the High Complexity task. Overall, our results indicate that identified temporal and spatio-temporal features from PFC's hemodynamic activity are promising biomarkers in classifying subjects with TBI.

Serum alkaline phosphatase as a predictor of worsening renal function in patients with acute decompensated heart failure.

PubMed

Yamazoe, Masahiro; Mizuno, Atsushi; Nishi, Yutaro; Niwa, Koichiro; Isobe, Mitsuaki

2016-05-01

Venous congestion has come into focus as an important hemodynamic factor for worsening renal function (WRF) in patients with acute decompensated heart failure (ADHF). Serum alkaline phosphatase (ALP) was reported as a biological marker of liver congestion in ADHF. The purpose of this study was to determine whether ALP is a predictor of WRF in patients with ADHF. We enrolled consecutive patients admitted to a single cardiovascular center with ADHF, and defined WRF as an increase in creatinine of >0.3 mg/dl during hospitalization and chronic kidney disease (CKD) as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2). The patients were classified into tertiles by ALP level (<203, 203-278, and >278 IU/L). A total of 972 patients (mean age, 76±13 years; 54% male) were retrospectively analyzed. WRF was identified in 132 patients (13.6%). In multivariate logistic regression analysis, baseline CKD [odds ratio (OR) 2.46, 95% confidence interval (CI) 1.48-4.08, p<0.001], serum albumin (OR 0.52, 95% CI 0.35-0.77, p=0.001), and diabetes (OR 2.07, 95% CI 1.37-3.12, p<0.001) were associated with WRF. Compared with the lowest tertile (ALP <203 IU/L), an adjusted OR of WRF was 1.69 (95% CI 1.02-2.79, p=0.04) in the middle tertile (ALP, 203-278 IU/L) and 1.95 (95% CI 1.20-3.21, p=0.008) in the highest tertile (ALP >278 IU/L). Serum ALP is an independent predictor of WRF in the clinical course of ADHF. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Autonomic control of the heart is altered in Sprague-Dawley rats with spontaneous hydronephrosis

PubMed Central

Arnold, Amy C.; Shaltout, Hossam A.; Gilliam-Davis, Shea; Kock, Nancy D.

2011-01-01

The renal medulla plays an important role in cardiovascular regulation, through interactions with the autonomic nervous system. Hydronephrosis is characterized by substantial loss of renal medullary tissue. However, whether alterations in autonomic control of the heart are observed in this condition is unknown. Thus we assessed resting hemodynamics and baroreflex sensitivity (BRS) for control of heart rate in urethane/chloralose-anesthetized Sprague-Dawley rats with normal or hydronephrotic kidneys. While resting arterial pressure was similar, heart rate was higher in rats with hydronephrosis (290 ± 12 normal vs. 344 ± 11 mild/moderate vs. 355 ± 13 beats/min severe; P < 0.05). The evoked BRS to increases, but not decreases, in pressure was lower in hydronephrotic rats (1.06 ± 0.06 normal vs. 0.72 ± 0.10 mild/moderate vs. 0.63 ± 0.07 ms/mmHg severe; P < 0.05). Spectral analysis methods confirmed reduced parasympathetic function in hydronephrosis, with no differences in measures of indirect sympathetic activity among conditions. As a secondary aim, we investigated whether autonomic dysfunction in hydronephrosis is associated with activation of the renin-angiotensin system (RAS). There were no differences in circulating angiotensin peptides among conditions, suggesting that the impaired autonomic function in hydronephrosis is independent of peripheral RAS activation. A possible site for angiotensin II-mediated BRS impairment is the solitary tract nucleus (NTS). In normal and mild/moderate hydronephrotic rats, NTS administration of the angiotensin II type 1 receptor antagonist candesartan significantly improved the BRS, suggesting that angiotensin II provides tonic suppression to the baroreflex. In contrast, angiotensin II blockade produced no significant effect in severe hydronephrosis, indicating that at least within the NTS baroreflex suppression in these animals is independent of angiotensin II. PMID:21460193

Assessment of the relationship between renal volume and renal function after minimally-invasive partial nephrectomy: the role of computed tomography and nuclear renal scan.

PubMed

Bertolo, Riccardo; Fiori, Cristian; Piramide, Federico; Amparore, Daniele; Barrera, Monica; Sardo, Diego; Veltri, Andrea; Porpiglia, Francesco

2018-05-14

To evaluate the correlation between the loss of renal function as assessed by Tc99MAG-3 renal scan and the loss of renal volume as calculated by volumetric assessment on CT-scan in patients who underwent minimally-invasive partial nephrectomy (PN). PN prospectively-maintained database was retrospectively queried for patients who underwent minimally-invasive PN (2012-2017) for renal mass

Pyruvate in oral rehydration salt improves hemodynamics, vasopermeability and survival after burns in dogs.

PubMed

Liu, Rui; Hu, Xiao-Hang; Wang, Shu-Ming; Guo, Si-Jia; Li, Zong-Yu; Bai, Xiao-Dong; Zhou, Fang-Qiang; Hu, Sen

2016-06-01

To investigate whether pyruvate-enriched oral rehydration solution (Pyr-ORS), compared with citrate-enriched ORS (Cit-ORS), improves hemodynamics and organ function by alleviating vasopermeability and plasma volume loss during intra-gastric fluid rehydration in dogs with severe burn. Forty dogs subjected to severe burn were randomly divided into four groups (n=10): two oral rehydrated groups with Pyr-ORS and Cit-ORS (group PR and group CR), respectively, according to the Parkland formula during the first 24h after burns. Other two groups were the intravenous (IV) resuscitation (group VR) with lactated Ringer's solution with the same dosage and no fluid rehydration (group NR). During the next 24h, all groups received the same IV infusion. The hemodynamics, plasma volume, vasopermeability and water contents and function of various organs were determined. Plasma levels of vascular endothelial growth factor (VEGF) and platelet activating factor (PAF) were detected by ELISA. Hemodynamics parameters were significantly improved in group PR superior to group CR after burns. Levels of VEGF and PAF were significantly lower in group PR than in group CR. Organ function parameters were also greatly preserved in group PR, relative to groups CR and NR. Lactic acidosis was fully corrected and survival increased in group PR (50.0%), compared to group CR (20.0%). Pyr-ORS was more effective than Cit-ORS in improving hemodynamics, visceral blood perfusion and organ function by alleviating vasopermeability-induced visceral edema and plasma volume loss in dogs with severe burn. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

[Renal cirsoid aneurysm (congenital arteriovenous fistula): a rare cause of severe hematuria].

PubMed

Pereira Arias, José Gregorio; Ullate Jaime, Vicente; Pereda Martínez, Esther; Gutiérrez Díez, José María; Ateca Díaz-Obregón, Ricardo; Ramírez Rodríguez, Maria Mar; Berreteaga Gallastegui, José Ramón

2007-06-01

Congenital arteriovenous fistulas are an exceptional clinical feature. Although they are frequently asymptomatic, their presentation as severe hematuria pose an excellent diagnostic exercise and often immediate therapeutic action. We report the case of a 75-year-old female patient presenting with severe hematuria producing anaemia, high blood pressure and congestive heart failure. Image tests revealed right ureteral-hydronephrosis with bladder blockage by blood clots. The endoscopic study (cystoscopy and ureterorenoscopy) alerted about the origin of the hematuria from the right kidney, finally requiring nephrectomy as definitive treatment. Pathology revealed the presence of a round formation with multiple vascular channels, arterial and venous, in the pyelocalicial submucosa, with focal epithelial erosion, compatible with congenital arteriovenous fistula. We review the diagnostic and therapeutic features in the literature. Renal congenital arteriovenous fistulas represent a diagnostic dilemma. They may present asymptomatic or condition clinical features derived from the shunt and high cardiac output (hypertensive cardiopathy and congestive heart failure) or from the erosion and acute hemorrhage into the urinary tract (severe renal hematuria). Treatment should be conservative with embolization or supraselective sclerosis. Nevertheless, in cases of big fistulas, post embolization revascularization, or hemodynamic instability nephrectomy is an excellent option.

Restenosis after renal artery angioplasty and stenting: Incidence and risk factors

PubMed Central

Corriere, Matthew A.; Edwards, Matthew S.; Pearce, Jeffrey D.; Andrews, Jeanette S.; Geary, Randolph L.; Hansen, Kimberley J.

2010-01-01

Background Management of renal artery stenosis (RAS) with primary renal artery percutaneous angioplasty and stenting (RA-PTAS) is associated with a low risk of periprocedural death and major complications; however, restenosis develops in a subset of patients and repeat intervention may be required. We examined the incidence of restenosis after RA-PTAS and associations with clinical factors. Methods Consecutive patients undergoing RA-PTAS for hemodynamically significant atherosclerotic RAS associated with hypertension or ischemic nephropathy, or both, between October 2003 and September 2007 were identified from a registry. Restenosis was defined using duplex ultrasound (DUS) imaging as a renal artery postintervention peak systolic velocity (PSV) ≥180 cm/s. The incidence and temporal distribution of restenosis was analyzed using survival analysis based on treated kidneys. Associations between clinical factors and recurrent stenosis were examined using proportional hazards regression. Results RA-PTAS was performed on 112 kidneys for atherosclerotic RAS during the study period. Initial postintervention renal artery DUS imaging confirming PSV <180 cm/s in 101 kidneys, which formed the basis of this analysis. Estimated restenosis-free survival was 50% at 12 months and 40% at 18 months. Decreased risk of restenosis was associated with preoperative statin use (hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.16–0.74; P = .006) and increased preoperative diastolic blood pressure (DBP; HR, 0.70 per 10-mm Hg increase in preoperative DBP; 95% CI, 0.49–0.99; P = .049). No other factors assessed were associated with restenosis. Conclusion Restenosis occurs in a substantial number of patients treated with RA-PTAS. Preoperative statin medication use and increased preoperative DBP are associated with reduced risk of restenosis. In the absence of contraindications, statins should be considered standard therapy for patients with atherosclerotic renal artery stenosis. PMID:19595532

Cyclosporine Induces Endothelial Cell Release of Complement-Activating Microparticles

PubMed Central

Renner, Brandon; Klawitter, Jelena; Goldberg, Ryan; McCullough, James W.; Ferreira, Viviana P.; Cooper, James E.; Christians, Uwe

2013-01-01

Defective control of the alternative pathway of complement is an important risk factor for several renal diseases, including atypical hemolytic uremic syndrome. Infections, drugs, pregnancy, and hemodynamic insults can trigger episodes of atypical hemolytic uremic syndrome in susceptible patients. Although the mechanisms linking these clinical events with disease flares are unknown, recent work has revealed that each of these clinical conditions causes cells to release microparticles. We hypothesized that microparticles released from injured endothelial cells promote intrarenal complement activation. Calcineurin inhibitors cause vascular and renal injury and can trigger hemolytic uremic syndrome. Here, we show that endothelial cells exposed to cyclosporine in vitro and in vivo release microparticles that activate the alternative pathway of complement. Cyclosporine-induced microparticles caused injury to bystander endothelial cells and are associated with complement-mediated injury of the kidneys and vasculature in cyclosporine-treated mice. Cyclosporine-induced microparticles did not bind factor H, an alternative pathway regulatory protein present in plasma, explaining their complement-activating phenotype. Finally, we found that in renal transplant patients, the number of endothelial microparticles in plasma increases 2 weeks after starting tacrolimus, and treatment with tacrolimus associated with increased C3 deposition on endothelial microparticles in the plasma of some patients. These results suggest that injury-associated release of endothelial microparticles is an important mechanism by which systemic insults trigger intravascular complement activation and complement-dependent renal diseases. PMID:24092930

Presence of transient hydronephrosis immediately after surgery has a limited influence on renal function 1 year after ileal neobladder construction.

PubMed

Narita, Takuma; Hatakeyama, Shingo; Koie, Takuya; Hosogoe, Shogo; Matsumoto, Teppei; Soma, Osamu; Yamamoto, Hayato; Yoneyama, Tohru; Tobisawa, Yuki; Yoneyama, Takahiro; Hashimoto, Yasuhiro; Ohyama, Chikara

2017-08-31

Urinary tract obstruction and postoperative hydronephrosis are risk factor for renal function deterioration after orthotopic ileal neobladder construction. However, reports of relationship between transient hydronephrosis and renal function are limited. We assess the influence of postoperative transient hydronephrosis on renal function in patients with orthotopic ileal neobladder construction. Between January 2006 and June 2013, we performed radical cystectomy in 164 patients, and 101 received orthotopic ileal neobladder construction. This study included data available from 64 patients with 128 renal units who were enrolled retrospectively. The hydronephrosis grade of each renal unit scored 0-4. The patients were divided into 4 groups according to the grade of hydronephrosis: control, low, intermediate, and high. The grade of postoperative hydronephrosis was compared with renal function 1 month and 1 year after surgery. There were no significant differences in renal function before surgery between groups. One month after surgery, the presence of hydronephrosis was significantly associated with decreased renal function. However, 1 year after urinary diversion hydronephrosis grades were improved significantly, and renal function was comparable between groups. Postoperative hydronephrosis at 1 month had no significant influence on renal function 1 year after ileal neobladder construction. Limitations include retrospective design, short follow-up periods, and a sample composition. The presence of transient hydronephrosis immediately after surgery may have limited influence on renal function 1 year after ileal neobladder construction.

Impact of pretransplant renal function on survival after liver transplantation.

PubMed

Gonwa, T A; Klintmalm, G B; Levy, M; Jennings, L S; Goldstein, R M; Husberg, B S

1995-02-15

To determine the effect of pretransplant liver function on survival following orthotopic liver transplantation and to quantify the effects of cyclosporine administration on long-term renal function in patients undergoing liver transplant, we performed an analysis of a prospectively maintained database. Data from 569 consecutive patients undergoing liver transplantation alone who were treated with CsA for immunosuppression were used for this study. Actuarial graft and patient survival rates were calculated using Kaplan-Meier statistics. Glomerular filtration rates, serum creatinine, and the use of various immunosuppressives were analyzed for this study. The initial analysis demonstrated that patients presenting for liver transplant with hepatorenal syndrome have a significantly decreased acturial patient survival after liver transplant at 5 years compared with patients without hepatorenal syndrome (60% vs. 68%, P < 0.03). Patients with hepatorenal syndrome recovered their renal function after liver transplant. Patients who had hepatorenal syndrome were sicker and required longer stays in the intensive care unit, longer hospitalizations, and more dialysis treatments after transplantation compared with patients who did not have hepatorenal syndrome. The incidence of end-stage renal disease after liver transplantation in patients who had hepatorenal syndrome was 7%, compared with 2% in patients who did not have hepatorenal syndrome. To more fully examine the effect of pretransplant renal function on posttransplant survival, the non-hepatorenal syndrome patients were divided into quartiles depending upon their pretransplant renal function. The patients with the lowest pretransplant renal function had the same survival as the patients with the highest pretransplant renal function. In addition, there was no increased incidence of acute or chronic rejection in any of the groups. The patients with the lower pretransplant renal function were treated with more azathioprine to maintain renal function and had a negligible decrease in glomerular filtration rate following transplant. Conversely, patients with the highest level of renal function pretransplant had a 40% decline in renal function in the first year, but maintained stable renal function up to 4 years after transplant. We conclude that pretransplant renal function other than hepato-renal syndrome has no effect on patient survival after orthotopic liver transplant. Renal function after liver transplant is stable after an initial decline, despite continued administration of CsA.(ABSTRACT TRUNCATED AT 400 WORDS)

Near-infrared spectroscopy assessment of divided visual attention task-invoked cerebral hemodynamics during prolonged true driving

NASA Astrophysics Data System (ADS)

Li, Ting; Zhao, Yue; Sun, Yunlong; Gao, Yuan; Su, Yu; Hetian, Yiyi; Chen, Min

2015-03-01

Driver fatigue is one of the leading causes of traffic accidents. It is imperative to develop a technique to monitor fatigue of drivers in real situation. Near-infrared spectroscopy (fNIRS) is now capable of measuring brain functional activity noninvasively in terms of hemodynamic responses sensitively, which shed a light to us that it may be possible to detect fatigue-specified brain functional activity signal. We developed a sensitive, portable and absolute-measure fNIRS, and utilized it to monitor cerebral hemodynamics on car drivers during prolonged true driving. An odd-ball protocol was employed to trigger the drivers' visual divided attention, which is a critical function in safe driving. We found that oxyhemoglobin concentration and blood volume in prefrontal lobe dramatically increased with driving duration (stand for fatigue degree; 2-10 hours), while deoxyhemoglobin concentration increased to the top at 4 hours then decreased slowly. The behavior performance showed clear decrement only after 6 hours. Our study showed the strong potential of fNIRS combined with divided visual attention protocol in driving fatigue degree monitoring. Our findings indicated the fNIRS-measured hemodynamic parameters were more sensitive than behavior performance evaluation.

Clinical course of dengue fever and its impact on renal function in renal transplant recipients and patients with chronic kidney disease.

PubMed

Arun Thomas, E T; George, Jacob; Sruthi, Devi; Vineetha, N S; Gracious, Noble

2018-04-01

Dengue fever is a mosquito-borne viral disease endemic in many tropical and sub-tropical countries. There is only limited data in the literature about dengue fever in renal transplant recipients and patients with chronic kidney disease. This study compares the clinical course of dengue fever and its impact on renal function in renal transplant recipients, patients with chronic kidney disease and patients with normal base line renal function. An observational study was conducted from 1 st May to 31 st July 2017, at a tertiary care centre of South India. A major epidemic of dengue had occurred during the study period. Twelve renal transplant recipients, 22 patients with CKD and 58 patients with normal baseline renal function (control group) admitted with dengue fever were prospectively studied. Nadir WBC count was lowest in renal transplant recipients (2575 + 1187/mm 3 ), [P<0.001]. Renal transplant recipients took more time for normalisation of platelet count (6 + 4.5 days), [P<0.001]. All 22 patients with CKD and 11 of 12 renal transplant recipients had worsening of renal function where as only 17 of 58 patients in the control group had worsening [P<0.001]. Sixteen patients with CKD, one renal transplant recipient and none among control group required hemodialysis [P<0.001]. Dialysis requiring patients had more hemoconcentration (52.5+ 19.9% increase in haemoglobin), [P<0.001]. Seven patients with CKD were dialysis dependent at the end of 2 weeks. Clinical features of dengue fever were different in renal transplant recipients and patients with CKD. Severe worsening of renal function was common in CKD patients. Worsening of renal function in renal transplant recipients was less severe and transient. This article is protected by copyright. All rights reserved.

Hemodialysis as a treatment of severe accidental hypothermia.

PubMed

Caluwé, Rogier; Vanholder, Raymond; Dhondt, Annemieke

2010-03-01

We describe a case of severe accidental hypothermia (core body temperature 23.2 degrees C) successfully treated with hemodialysis in a diabetic patient with preexisting renal insufficiency. Consensus exists about cardiopulmonary bypass as the treatment of choice in cases of severe accidental hypothermia with cardiac arrest. Prospective randomized controlled trials comparing the different rewarming modalities for hemodynamically stable patients with hypothermia, however, are lacking. In our opinion, the choice of a rewarming technique should be patient tailored, knowing that hemodialysis is an efficient, minimally invasive, and readily available technique with the advantage of providing electrolyte support.

Geometric Alteration of Renal Arteries After Fenestrated Grafting and the Impact on Renal Function.

PubMed

Ou, Jiale; Chan, Yiu-Che; Chan, Crystal Yin-Tung; Cheng, Stephen W K

2017-05-01

This study aims to investigate the degree of geometric change on renal arteries and its impact on renal function after fenestrated endovascular aortic repair (fEVAR). Twenty-five patients with fEVAR were included. There were 47 renal arteries target vessels, and 43 of these (22 left and 21 right vessels) stented successfully. Their preoperative and first postoperative follow-up computed tomography (CT) images were reconstructed using the Aquarius workstation (TeraRecon, San Mateo, CA, USA). The superior mesenteric artery (SMA) or celiac axis (if SMA was stented) was appointed as reference origin. The longitudinal orientation of a renal artery or a stent was represented by a takeoff angle (ToA) between the renal artery or stent and the distal abdominal aorta. The postoperative stent ToAs were compared with those of preoperative renal arteries. Preoperative and short-term postoperative serum creatinine levels were measured. Renal function impairment was indicated as a >30% or >2.0 mg/dL rise in serum creatinine compared to the preoperative level. The relationship between postoperative renal function impairment and the stent orientation or geometric changes in renal arteries was correlated. The patency rate of renal arteries was 100% at the first postoperative CT review. The average ToAs of both renal arteries were significantly enlarged after stenting (P < 0.05). Seven stent deformations (16.3%) in four patients (16.0%) were observed. They were attributed to caudal misalignment of the fenestrated stent graft (n = 6) or inaccurate graft sizing (n = 1). There was no stent fracture or target vessel loss. Postoperatively, nine patients (36.0%) at day 1 and 10 patients (41.7%) after 3 months suffered the renal function impairment. This was found not to be associated with the stent angulation or angular change of the renal arteries (both P > 0.05). The three patients with stent deformation due to misalignment suffered postoperative renal function impairment and continuing deterioration in renal function. Implanted renal stents could angulate renal arteries more cephalad after fenestrated stenting. Postoperative renal function impairment was not associated with the stent orientation and changes in vessel orientation. Accurate fenestrated alignment is important to maintain stent performance and preserve renal function. Copyright © 2017 Elsevier Inc. All rights reserved.

Endothelin-A Receptor Antagonism after Renal Angioplasty Enhances Renal Recovery in Renovascular Disease

PubMed Central

Tullos, Nathan; Stewart, Nicholas J.; Surles, Bret

2015-01-01

Percutaneous transluminal renal angioplasty/stenting (PTRAS) is frequently used to treat renal artery stenosis and renovascular disease (RVD); however, renal function is restored in less than one half of the cases. This study was designed to test a novel intervention that could refine PTRAS and enhance renal recovery in RVD. Renal function was quantified in pigs after 6 weeks of chronic RVD (induced by unilateral renal artery stenosis), established renal damage, and hypertension. Pigs with RVD then underwent PTRAS and were randomized into three groups: placebo (RVD+PTRAS), chronic endothelin-A receptor (ET-A) blockade (RVD+PTRAS+ET-A), and chronic dual ET-A/B blockade (RVD+PTRAS+ET-A/B) for 4 weeks. Renal function was again evaluated after treatments, and then, ex vivo studies were performed on the stented kidney. PTRAS resolved renal stenosis, attenuated hypertension, and improved renal function but did not resolve renal microvascular rarefaction, remodeling, or renal fibrosis. ET-A blocker therapy after PTRAS significantly improved hypertension, microvascular rarefaction, and renal injury and led to greater recovery of renal function. Conversely, combined ET-A/B blockade therapy blunted the therapeutic effects of PTRAS alone or PTRAS followed by ET-A blockade. These data suggest that ET-A receptor blockade therapy could serve as a coadjuvant intervention to enhance the outcomes of PTRAS in RVD. These results also suggest that ET-B receptors are important for renal function in RVD and may contribute to recovery after PTRAS. Using clinically available compounds and techniques, our results could contribute to both refinement and design of new therapeutic strategies in chronic RVD. PMID:25377076

Predictive abilities of cardiovascular biomarkers to rapid decline of renal function in Chinese community-dwelling population: a 5-year prospective analysis.

PubMed

Fu, Shihui; Liu, Chunling; Luo, Leiming; Ye, Ping

2017-11-09

Predictive abilities of cardiovascular biomarkers to renal function decline are more significant in Chinese community-dwelling population without glomerular filtration rate (GFR) below 60 ml/min/1.73m 2 , and long-term prospective study is an optimal choice to explore this problem. Aim of this analysis was to observe this problem during the follow-up of 5 years. In a large medical check-up program in Beijing, there were 948 participants with renal function evaluated at baseline and follow-up of 5 years. Physical examinations were performed by well-trained physicians. Blood samples were analyzed by qualified technicians in central laboratory. Median rate of renal function decline was 1.46 (0.42-2.91) mL/min/1.73m 2 /year. Rapid decline of renal function had a prevalence of 23.5% (223 participants). Multivariate linear and Logistic regression analyses confirmed that age, sex, baseline GFR, homocysteine and N-terminal pro B-type natriuretic peptide (NT-proBNP) had independently predictive abilities to renal function decline rate and rapid decline of renal function (p < 0.05 for all). High-sensitivity cardiac troponin T (hs-cTnT), carotid femoral pulse wave velocity and central augmentation index had no statistically independent association with renal function decline rate and rapid decline of renal function (p > 0.05 for all). Homocysteine and NT-proBNP rather than hs-cTnT had independently predictive abilities to rapid decline of renal function in Chinese community-dwelling population without GFR below 60 ml/min/1.73m 2 . Baseline GFR was an independent factor predicting the rapid decline of renal function. Arterial stiffness and compliance had no independent effect on rapid decline of renal function. This analysis has a significant implication for public health, and changing the homocysteine and NT-proBNP levels might slow the rapid decline of renal function.

The additive effects of atorvastatin and insulin on renal function and renal organic anion transporter 3 function in diabetic rats.

PubMed

Thongnak, Laongdao; Pongchaidecha, Anchalee; Jaikumkao, Krit; Chatsudthipong, Varanuj; Chattipakorn, Nipon; Lungkaphin, Anusorn

2017-10-19

Hyperglycemia-induced oxidative stress is usually found in diabetic condition. 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, statins, are widely used as cholesterol-lowering medication with several "pleiotropic" effects in diabetic patients. This study aims to evaluate whether the protective effects of atorvastatin and insulin on renal function and renal organic anion transporter 3 (Oat3) function involve the modulation of oxidative stress and pancreatic function in type 1 diabetic rats. Type 1 diabetes was induced by intraperitoneal injection of streptozotocin (50 mg/kg BW). Atorvastatin and insulin as single or combined treatment were given for 4 weeks after diabetic condition had been confirmed. Diabetic rats demonstrated renal function and renal Oat3 function impairment with an increased MDA level and decreased SOD protein expression concomitant with stimulation of renal Nrf2 and HO-1 protein expression. Insulin plus atorvastatin (combined) treatment effectively restored renal function as well as renal Oat3 function which correlated with the decrease in hyperglycemia and oxidative stress. Moreover, pancreatic inflammation and apoptosis in diabetic rats were ameliorated by the combined drugs treatment. Therefore, atorvastatin plus insulin seems to exert the additive effect in improving renal functionby alleviating hyperglycemiaand the modulation of oxidative stress, inflammation and apoptosis.

Effects of continuous and pulsatile flows generated by ventricular assist devices on renal function and pathology.

PubMed

Miyamoto, Takuma; Karimov, Jamshid H; Fukamachi, Kiyotaka

2018-03-01

Continuous-flow (CF) left ventricular assist devices (LVADs) are widely used to treat end-stage heart failure. Despite substantial improvement in clinical results, numerous complications remain associated with this technology. Worsening renal function is one, associated with morbidity and mortality in patients supported by CF LVADs. The effects of CF LVAD support on renal function have been investigated since the mid-1990s by many research groups. Area covered: We review the current status of LVAD therapy, experimental results regarding the effects of types of flow generated by LVADs on renal function and pathology, changes in renal function after LVAD implant, the influence of renal function on outcomes, and risk factors for renal dysfunction post implant. This information was obtained through online databases and direct extraction of single studies. Expert commentary: Immediately after CF LVAD implantation, renal function improves temporarily as patients recover from the kidneys' previously low perfusion and congestive state. However, many studies have shown that this initially recovered renal function gradually declines during long-term CF LVAD support. Although it is known that CF LVAD support adversely affects renal function over the long term, just how it does has not yet been clearly defined in terms of clinical symptoms or signs.

Echocardiographic predictors of change in renal function with intravenous diuresis for decompensated heart failure.

PubMed

Gannon, Stephen A; Mukamal, Kenneth J; Chang, James D

2018-06-14

The aim of this study was to identify echocardiographic predictors of improved or worsening renal function during intravenous diuresis for decompensated heart failure. Secondary aim included defining the incidence and clinical risk factors for acute changes in renal function with decongestion. A retrospective review of 363 patients admitted to a single centre for decompensated heart failure who underwent intravenous diuresis and transthoracic echocardiography was conducted. Clinical, echocardiographic, and renal function data were retrospectively collected. A multinomial logistic regression model was created to determine relative risk ratios for improved renal function (IRF) or worsening renal function (WRF). Within this cohort, 36% of patients experienced WRF, 35% had stable renal function, and 29% had IRF. Patients with WRF were more likely to have a preserved left ventricular ejection fraction compared with those with stable renal function or IRF (P = 0.02). Patients with IRF were more likely to have a dilated, hypokinetic right ventricle compared with those with stable renal function or WRF (P ≤ 0.01), although this was not significant after adjustment for baseline characteristics. Left atrial size, left ventricular linear dimensions, and diastolic function did not significantly predict change in renal function. An acute change in renal function occurred in 65% of patients admitted with decompensated heart failure. WRF was statistically more likely in patients with a preserved left ventricular ejection fraction. A trend towards IRF was noted in patients with global right ventricular dysfunction. © 2018 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.

Acute metformin intoxication: 2012 experience of Emergency Departement of Lodi, Italy.

PubMed

Acquistapace, Giulia; Rossi, Marco; Garbi, Mara; Cosci, Pablo; Canetta, Ciro; Manelli, Anna; Ricevuti, Giovanni

2014-10-01

Background: Metformin is a biguanide antihyperglycemic agent that decreases insulin resistance. It is removed through renal mechanisms and its clearance is reduced in renal failure. Metformin ingestion should always be considered in the differential diagnosis of any patient with metabolic acidosis and increased lactate level. Hemodialysis and continuous veno-venous hemofiltration (CVVH) are both efficient methods to treat metformin intoxication and correct metabolic abnormalities. Patient 1: A 63-year-old man with type 2 diabetes mellitus presented to emergency department (ED) of Lodi (Italy) for dyspnea. He also reported having diarrhea for 10 days. Initial investigations revealed metabolic acidosis with hyperlactatemia and hypoglycemia (54 mg/dL), metformin concentration was 41 μg/mL (normal value <4 μg/mL). His hemodynamic condition became rapidly unstable and hypotension worsened despite CVVH being performed. Death occurred in 24 h. Patient 2: A 76-year-old man with type 2 diabetes mellitus presented to ED of Lodi for dyspnea. He referred a recent surgery amputation of the left foot's fifth phalanx for osteomyelitis, in levofloxacin therapy. Initial investigations revealed metabolic acidosis with hyperlactatemia and severe hypoglycemia (20 mg/dL). Two hemodialysis sessions were performed with complete normalization of the serum concentration of metformin. In our two cases the genesis of metformin intoxication was clear, powered by acute renal failure, but less obvious was the etiology of acute renal damage responsible for metformin accumulation. Damage due to renal hypoperfusion or the direct toxic effect of metformin should be considered. Additionally, for the second patient, we can also hypothesize that interstitial nephritis was exacerbated by levofloxacin.

Effect of healthy aging on renal vascular responses to local cooling and apnea

PubMed Central

Patel, Hardikkumar M.; Mast, Jessica L.; Sinoway, Lawrence I.

2013-01-01

Sympathetically mediated renal vasoconstriction may contribute to the pathogenesis of hypertension in older adults, but empirical data in support of this concept are lacking. In 10 young (26 ± 1 yr) and 11 older (67 ± 2 yr) subjects, we quantified acute hemodynamic responses to three sympathoexcitatory stimuli: local cooling of the forehead, cold pressor test (CPT), and voluntary apnea. We hypothesized that all stimuli would increase mean arterial blood pressure (MAP) and renal vascular resistance index (RVRI) and that aging would augment these effects. Beat-by-beat MAP, heart rate (HR), and renal blood flow velocity (from Doppler) were measured in the supine posture, and changes from baseline were compared between groups. In response to 1°C forehead cooling, aging was associated with an augmented MAP (20 ± 3 vs. 6 ± 2 mmHg) and RVRI (35 ± 6 vs. 16 ± 9%) but not HR. In older adults, there was a positive correlation between the cold-induced pressor response and forehead pain (R = 0.726), but this effect was not observed in young subjects. The CPT raised RVRI in both young (56 ± 13%) and older (45 ± 8%) subjects, but this was not different between groups. Relative to baseline, end-expiratory apnea increased RVRI to a similar extent in both young (46 ± 14%) and older (41 ± 9%) subjects. During sympathetic activation, renal vasoconstriction occurred in both groups. Forehead cooling caused an augmented pressor response in older adults that was related to pain perception. PMID:23640587

Effect of renal replacement therapy on viscosity in end-stage renal disease patients.

PubMed

Feriani, M; Kimmel, P L; Kurantsin-Mills, J; Bosch, J P

1992-02-01

Viscosity, an important determinant of microcirculatory hemodynamics, is related to hematocrit (HCT), and may be altered by renal failure or its treatment. To assess these factors, we studied the effect of dialysis on the viscosity of whole blood, plasma, and reconstituted 70% HCT blood of eight continuous ambulatory peritoneal dialysis (CAPD) and nine hemodialysis (HD) patients under steady shear flow conditions at different shear rates, before and after dialysis, compared with nine normal subjects. The density of the red blood cells (RBCs), a marker of cell hydration, was measured in HD patients by a nonaqueous differential floatation technique. Whole blood viscosity was higher in controls than patients, and correlated with HCT before treatment (P less than 0.05) at shear rates of 11.5 to 230 s-1) in HD patients, and 23 to 230 s-1 in all end-stage renal disease (ESRD) patients. In contrast, whole blood viscosity correlated with HCT in CAPD patients only at the lowest shear rates (2.3 and 5.75 s-1, P less than 0.05). Plasma viscosity was higher in CAPD patients than both HD patients before treatment and controls (P less than 0.05, analysis of variance [ANOVA]), despite lower plasma total protein, albumin, and similar fibrinogen concentration compared with HD patients. When all samples were reconstituted to 70% HCT, CAPD patients had higher whole blood viscosity than control subjects'. The high HCT blood viscosity of the ESRD patients was higher than control subjects' at capillary shear rates, suggesting increased RBC aggregation and decreased RBC deformability in patients with renal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy.

PubMed

Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

2014-01-01

Central blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. Twenty-five ASA I-II Group patients aged 65-80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. Significant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. Evaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning. Copyright © 2013 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

[Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy].

PubMed

Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

2014-01-01

Central blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. Twenty-five ASA I-II Group patients aged 65-80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. Significant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. Evaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning. Copyright © 2013 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Post-Discharge Worsening Renal Function in Patients with Type 2 Diabetes and Recent Acute Coronary Syndrome.

PubMed

Morici, Nuccia; Savonitto, Stefano; Ponticelli, Claudio; Schrieks, Ilse C; Nozza, Anna; Cosentino, Francesco; Stähli, Barbara E; Perrone Filardi, Pasquale; Schwartz, Gregory G; Mellbin, Linda; Lincoff, A Michael; Tardif, Jean-Claude; Grobbee, Diederick E

2017-09-01

Worsening renal function during hospitalization for an acute coronary syndrome is strongly predictive of in-hospital and long-term outcome. However, the role of post-discharge worsening renal function has never been investigated in this setting. We considered the placebo cohort of the AleCardio trial comparing aleglitazar with standard medical therapy among patients with type 2 diabetes mellitus and a recent acute coronary syndrome. Patients who had died or had been admitted to hospital for heart failure before the 6-month follow-up, as well as patients without complete renal function data, were excluded, leaving 2776 patients for the analysis. Worsening renal function was defined as a >20% reduction in estimated glomerular filtration rate from discharge to 6 months, or progression to macroalbuminuria. The Cox regression analysis was used to determine the prognostic impact of 6-month renal deterioration on the composite of all-cause death and hospitalization for heart failure. Worsening renal function occurred in 204 patients (7.34%). At a median follow-up of 2 years the estimated rates of death and hospitalization for heart failure per 100 person-years were 3.45 (95% confidence interval [CI], 2.46-6.36) for those with worsening renal function, versus 1.43 (95% CI, 1.14-1.79) for patients with stable renal function. At the adjusted analysis worsening renal function was associated with the composite endpoint (hazard ratio 2.65; 95% CI, 1.57-4.49; P <.001). Post-discharge worsening renal function is not infrequent among patients with type 2 diabetes and acute coronary syndromes with normal or mildly depressed renal function, and is a strong predictor of adverse cardiovascular events. Copyright © 2017 Elsevier Inc. All rights reserved.

The Physiologic Effects of Pneumoperitoneum in the Morbidly Obese

PubMed Central

Nguyen, Ninh T.; Wolfe, Bruce M.

2005-01-01

Objective: To review the physiologic effects of carbon dioxide (CO2) pneumoperitoneum in the morbidly obese. Summary Background Data: The number of laparoscopic bariatric operations performed in the United States has increased dramatically over the past several years. Laparoscopic bariatric surgery requires abdominal insufflation with CO2 and an increase in the intraabdominal pressure up to 15 mm Hg. Many studies have demonstrated the adverse consequences of pneumoperitoneum; however, few studies have examined the physiologic effects of pneumoperitoneum in the morbidly obese. Methods: A MEDLINE search from 1994 to 2003 was performed using the key words morbid obesity, laparoscopy, bariatric surgery, pneumoperitoneum, and gastric bypass. The authors reviewed papers evaluating the physiologic effects of pneumoperitoneum in morbidly obese subjects undergoing laparoscopy. The topics examined included alteration in acid-base balance, hemodynamics, femoral venous flow, and hepatic, renal, and cardiorespiratory function. Results: Physiologically, morbidly obese patients have a higher intraabdominal pressure at 2 to 3 times that of nonobese patients. The adverse consequences of pneumoperitoneum in morbidly obese patients are similar to those observed in nonobese patients. Laparoscopy in the obese can lead to systemic absorption of CO2 and increased requirements for CO2 elimination. The increased intraabdominal pressure enhances venous stasis, reduces intraoperative portal venous blood flow, decreases intraoperative urinary output, lowers respiratory compliance, increases airway pressure, and impairs cardiac function. Intraoperative management to minimize the adverse changes include appropriate ventilatory adjustments to avoid hypercapnia and acidosis, the use of sequential compression devices to minimizes venous stasis, and optimize intravascular volume to minimize the effects of increased intraabdominal pressure on renal and cardiac function. Conclusions: Morbidly obese patients undergoing laparoscopic bariatric surgery are at risk for intraoperative complications relating to the use of CO2 pneumoperitoneum. Surgeons performing laparoscopic bariatric surgery should understand the physiologic effects of CO2 pneumoperitoneum in the morbidly obese and make appropriate intraoperative adjustments to minimize the adverse changes. PMID:15650630

Three-dimensional Echocardiography of Right Ventricular Function Correlates with Severity of Pediatric Pulmonary Hypertension.

PubMed

Jone, Pei-Ni; Patel, Sonali S; Cassidy, Courtney; Ivy, David Dunbar

2016-12-01

Right ventricular function and biomarkers of B-type natriuretic peptide (BNP) and N-Terminal pro-BNP (NT pro-BNP) are used to determine the severity of right ventricular failure and outcomes from pulmonary hypertension. Real-time three-dimensional echocardiography (3DE) is a novel quantitative measure of the right ventricle and decreases the geometric assumptions from conventional two-dimensional echocardiography (2DE). We correlated right ventricular functional measures using 2DE and single-beat 3DE with biomarkers and hemodynamics to determine the severity of pediatric pulmonary hypertension. We retrospectively evaluated 35 patients (mean age 12.67 ± 5.78 years) with established pulmonary hypertension who had echocardiograms and biomarkers on the same day. Ten out of 35 patients had hemodynamic evaluation within 3 days. 2DE evaluation included tricuspid annular plane systolic excursion (TAPSE), right ventricular myocardial performance index from tissue Doppler imaging (RV TDI MPI), and right ventricular fractional area change (FAC). Three-dimensional echocardiography evaluation included right ventricular ejection fraction (EF), end-systolic volume, and end-diastolic volume. The quality of the 3DE was graded as good, fair, or poor. Pearson correlation coefficients were utilized to evaluate between biomarkers and echocardiographic parameters and between hemodynamics and echocardiography. Three-dimensional echocardiography and FAC correlated significantly with BNP and NT pro-BNP. TAPSE and RV TDI MPI did not correlate significantly with biomarkers. 3D right ventricular EF correlated significantly with hemodynamics. Two-dimensional echocardiography did not correlate with hemodynamics. Single-beat 3DE is a noninvasive, feasible tool in the quantification of right ventricular function and maybe more accurate than conventional 2DE in evaluating severity of pulmonary hypertension. © 2016 Wiley Periodicals, Inc.

Cardioinhibitory effect of atrial peptide in conscious rats.

PubMed

Allen, D E; Gellai, M

1987-03-01

The hemodynamic and renal excretory responses to 150-min atriopeptin II (AP II) infusion (330 ng X kg-1 X min-1) were assessed in five chronically instrumented rats with (FR protocol) and without (NR protocol) replaced urinary fluid losses. The observed changes were compared with those obtained by vehicle in the same rats. The hypotension seen with AP II infusion (120-min value: -27 +/- 2%, FR and NR responses combined) was due solely to a decreased cardiac output (CO; 120-min combined value: -34 +/- 3%). Total peripheral resistance remained unchanged or slightly elevated. A drop in stroke volume plus a later-developing (by 75-90 min) decrease in heart rate contributed to the CO decline. This latter bradycardic component, the opposite response to that typically produced reflexly by hypotension, was reversed by atropine sulfate treatment at 120 min and may thus be neural in origin. The finding of similar hemodynamic changes in the FR and NR rats and the lack of a significant effect of AP II on hematocrit suggest that volume depletion or a plasma extravasation were not contributors to the cardioinhibitory effect of the peptide.

Population pharmacokinetics of pomalidomide in patients with relapsed or refractory multiple myeloma with various degrees of impaired renal function.

PubMed

Li, Yan; Wang, Xiaomin; O'Mara, Edward; Dimopoulos, Meletios A; Sonneveld, Pieter; Weisel, Katja C; Matous, Jeffrey; Siegel, David S; Shah, Jatin J; Kueenburg, Elisabeth; Sternas, Lars; Cavanaugh, Chloe; Zaki, Mohamed; Palmisano, Maria; Zhou, Simon

2017-01-01

Pomalidomide is an immunomodulatory drug for treatment of relapsed or refractory multiple myeloma (rrMM) in patients who often have comorbid renal conditions. To assess the impact of renal impairment on pomalidomide exposure, a population pharmacokinetics (PPK) model of pomalidomide in rrMM patients with various degrees of impaired renal function was developed. Intensive and sparse pomalidomide concentration data collected from two clinical studies in rrMM patients with normal renal function, moderately impaired renal function, severely impaired renal function not requiring dialysis, and with severely impaired renal function requiring dialysis were pooled over the dose range of 2 to 4 mg, to assess specifically the influence of the impaired renal function as a categorical variable and a continuous variable on pomalidomide clearance and plasma exposure. In addition, pomalidomide concentration data collected on dialysis days from both the withdrawal (arterial) side and from the returning (venous) side of the dialyzer, from rrMM patients with severely impaired renal function requiring dialysis, were used to assess the extent to which dialysis contributes to the removal of pomalidomide from blood circulation. PPK analyses demonstrated that moderate to severe renal impairment not requiring dialysis has no influence on pomalidomide clearance or plasma exposure, as compared to those patients with normal renal function, while pomalidomide exposure increased approximately 35% in patients with severe renal impairment requiring dialysis on nondialysis days. In addition, dialysis increased total body pomalidomide clearance from 5 L/h to 12 L/h, indicating that dialysis will significantly remove pomalidomide from the blood circulation. Thus, pomalidomide should be administered post-dialysis on the days of dialysis.

Measuring residual renal function for hemodialysis adequacy: Is there an easier option?

PubMed

Davenport, Andrew

2017-10-01

Most patients starting hemodialysis (HD) have residual renal function. As such, there has been increased interest in starting patients with less frequent and shorter dialysis session times. However, for this incremental approach to be successful, patients require regular monitoring of residual renal function, so that as residual renal function declines, the amount of HD is appropriately increased. Currently most dialysis centers rely on interdialytic urine collections. However, many patients find these inconvenient and there may be marked intrapatient variability due to compliance issues. Thus, alternative markers of residual renal function are required for routine clinical practice. Currently three middle sized molecules; cystatin C, β2 microglobulin, and βtrace protein have been investigated as potential endogenous markers of glomerular filtration. Although none is ideal, combinations of these markers have been proposed to provide a more accurate estimation of glomerular clearance, and in particular cut offs for minimal residual renal function. However, in patients with low levels of residual renal function it remains unclear as to whether the benefits of residual renal function equally apply to glomerular filtration or tubular function. © 2017 International Society for Hemodialysis.

Value of Nephrometry Score Constituents on Perioperative Outcomes and Split Renal Function in Patients Undergoing Minimally Invasive Partial Nephrectomy.

PubMed

Watts, Kara L; Ghosh, Propa; Stein, Solomon; Ghavamian, Reza

2017-01-01

To assess the relationship between individual nephrometry score (NS) constituents (RENAL) on perioperative outcomes and renal function of the surgical kidney in patients undergoing laparoscopic partial nephrectomy or robotic-assisted partial nephrectomy. Two hundred forty-five patients who underwent laparoscopic partial nephrectomy or robotic-assisted partial nephrectomy between 2005 and 2014 were retrospectively reviewed. Each renal mass' NS was calculated from preoperative computed tomography imaging. Multivariate regression analysis was used to evaluate the effect of NS variables on perioperative outcomes and change in overall renal function (as estimated by glomerular filtration rate) from preoperative to 1-year postoperative. A cohort analysis assessed the effect of NS variables on change in split renal function of the surgical kidney from pre- to postoperative based on nuclear medicine renal scintigraphy. Tumor radius (R), endophytic nature (E), and nearness to collecting system (N) variables significantly and incrementally predicted a longer operative time and warm ischemia time. Overall renal function based on glomerular filtration rate was not affected by any NS variable. However, percent function of the surgical kidney by renal scintigraphy significantly decreased postoperatively as R and E values increased. R, E, and N were associated with significant changes in warm ischemia time and operative time. R and E were associated with a significant decrease in split renal function of the surgical kidney at 1 year after surgery but not with overall renal function. R, E, and N are the NS constituents most relevant to perioperative outcomes and postoperative differential renal function after partial nephrectomy. Copyright © 2016. Published by Elsevier Inc.

Validation of a Functional Pyelocalyceal Renal Model for the Evaluation of Renal Calculi Passage While Riding a Roller Coaster.

PubMed

Mitchell, Marc A; Wartinger, David D

2016-10-01

The identification and evaluation of activities capable of dislodging calyceal renal calculi require a patient surrogate or validated functional pyelocalyceal renal model. To evaluate roller coaster facilitation of calyceal renal calculi passage using a functional pyelocalyceal renal model. A previously described adult ureteroscopy and renoscopy simulator (Ideal Anatomic) was modified and remolded to function as a patient surrogate. Three renal calculi of different sizes from the patient who provided the original computed tomographic urograph on which the simulator was based were used. The renal calculi were suspended in urine in the model and taken for 20 rides on the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando, Florida. The roller coaster rides were analyzed using variables of renal calculi volume, calyceal location, model position on the roller coaster, and renal calculi passage. Sixty renal calculi rides were analyzed. Independent of renal calculi volume and calyceal location, front seating on the roller coaster resulted in a passage rate of 4 of 24. Independent of renal calculi volume and calyceal location, rear seating on the roller coaster resulted in a passage rate of 23 of 36. Independent of renal calculi volume in rear seating, calyceal location differed in passage rates, with an upper calyceal calculi passage rate of 100%; a middle calyceal passage rate of 55.6%; and a lower calyceal passage rate of 40.0%. The functional pyelocalyceal renal model serves as a functional patient surrogate to evaluate activities that facilitate calyceal renal calculi passage. The rear seating position on the roller coaster led to the most renal calculi passages.

Response of the oxygen uptake efficiency slope to orthotopic heart transplantation: lack of correlation with changes in central hemodynamic parameters and resting lung function.

PubMed

Van Laethem, Christophe; Goethals, Marc; Verstreken, Sofie; Walravens, Maarten; Wellens, Francis; De Proft, Margot; Bartunek, Jozef; Vanderheyden, Marc

2007-09-01

Recently, a new linear measure of ventilatory response to exercise, the oxygen uptake efficiency slope (OUES), was proposed in the evaluation of heart failure patients. No data are available on the response of the OUES after orthotopic heart transplantation (HTx). Thirty patients who underwent HTx between 1999 and 2003 were included in the study. Data from maximal cardiopulmonary exercise test, resting pulmonary function and hemodynamic assessment were collected before the transplant at time of screening and 1 year after HTx. During the first year after HTx, OUES and normalized OUES for body weight (OUES/kg) increased significantly from 15.6 +/- 4.9 to 19.7 +/- 4.8 (p < 0.05). Changes in OUES/kg were significantly correlated with changes in peak VO2, VAT and peak VE, and inversely to changes in peak VD/VT, but not to changes in VE/VCO2 slope (all p < 0.05). Changes in OUES or OUES/kg did not correlate with any changes in measures of resting lung volumes or capacities and measures of central hemodynamic function after HTx. OUES improved significantly after HTx, but, similar to other exercise parameters, remained considerably impaired. The changes in OUES were highly correlated with the improvements in other exercise variables, but did not correlate with marked improvements in central hemodynamics or resting lung function.

An efficient multistage algorithm for full calibration of the hemodynamic model from BOLD signal responses.

PubMed

Zambri, Brian; Djellouli, Rabia; Laleg-Kirati, Taous-Meriem

2017-11-01

We propose a computational strategy that falls into the category of prediction/correction iterative-type approaches, for calibrating the hemodynamic model. The proposed method is used to estimate consecutively the values of the two sets of model parameters. Numerical results corresponding to both synthetic and real functional magnetic resonance imaging measurements for a single stimulus as well as for multiple stimuli are reported to highlight the capability of this computational methodology to fully calibrate the considered hemodynamic model. Copyright © 2017 John Wiley & Sons, Ltd.

Iohexol clearance is superior to creatinine-based renal function estimating equations in detecting short-term renal function decline in chronic heart failure.

PubMed

Cvan Trobec, Katja; Kerec Kos, Mojca; von Haehling, Stephan; Anker, Stefan D; Macdougall, Iain C; Ponikowski, Piotr; Lainscak, Mitja

2015-12-01

To compare the performance of iohexol plasma clearance and creatinine-based renal function estimating equations in monitoring longitudinal renal function changes in chronic heart failure (CHF) patients, and to assess the effects of body composition on the equation performance. Iohexol plasma clearance was measured in 43 CHF patients at baseline and after at least 6 months. Simultaneously, renal function was estimated with five creatinine-based equations (four- and six-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Cockcroft-Gault adjusted for lean body mass, Chronic Kidney Disease Epidemiology Collaboration equation) and body composition was assessed using bioimpedance and dual-energy x-ray absorptiometry. Over a median follow-up of 7.5 months (range 6-17 months), iohexol clearance significantly declined (52.8 vs 44.4 mL/[min ×1.73 m2], P=0.001). This decline was significantly higher in patients receiving mineralocorticoid receptor antagonists at baseline (mean decline -22% of baseline value vs -3%, P=0.037). Mean serum creatinine concentration did not change significantly during follow-up and no creatinine-based renal function estimating equation was able to detect the significant longitudinal decline of renal function determined by iohexol clearance. After accounting for body composition, the accuracy of the equations improved, but not their ability to detect renal function decline. Renal function measured with iohexol plasma clearance showed relevant decline in CHF patients, particularly in those treated with mineralocorticoid receptor antagonists. None of the equations for renal function estimation was able to detect these changes. ClinicalTrials.gov registration number: NCT01829880.

Dynamic physiological modeling for functional diffuse optical tomography

PubMed Central

Diamond, Solomon Gilbert; Huppert, Theodore J.; Kolehmainen, Ville; Franceschini, Maria Angela; Kaipio, Jari P.; Arridge, Simon R.; Boas, David A.

2009-01-01

Diffuse optical tomography (DOT) is a noninvasive imaging technology that is sensitive to local concentration changes in oxy- and deoxyhemoglobin. When applied to functional neuroimaging, DOT measures hemodynamics in the scalp and brain that reflect competing metabolic demands and cardiovascular dynamics. The diffuse nature of near-infrared photon migration in tissue and the multitude of physiological systems that affect hemodynamics motivate the use of anatomical and physiological models to improve estimates of the functional hemodynamic response. In this paper, we present a linear state-space model for DOT analysis that models the physiological fluctuations present in the data with either static or dynamic estimation. We demonstrate the approach by using auxiliary measurements of blood pressure variability and heart rate variability as inputs to model the background physiology in DOT data. We evaluate the improvements accorded by modeling this physiology on ten human subjects with simulated functional hemodynamic responses added to the baseline physiology. Adding physiological modeling with a static estimator significantly improved estimates of the simulated functional response, and further significant improvements were achieved with a dynamic Kalman filter estimator (paired t tests, n = 10, P < 0.05). These results suggest that physiological modeling can improve DOT analysis. The further improvement with the Kalman filter encourages continued research into dynamic linear modeling of the physiology present in DOT. Cardiovascular dynamics also affect the blood-oxygen-dependent (BOLD) signal in functional magnetic resonance imaging (fMRI). This state-space approach to DOT analysis could be extended to BOLD fMRI analysis, multimodal studies and real-time analysis. PMID:16242967

Doppler Assessment of Diastolic Function Reflect the Severity of Injury in Rats With Chronic Heart Failure.

PubMed

Sanchez, Pablo; Lancaster, Jordan J; Weigand, Kyle; Mohran, Saffie-Alrahman Ezz-Eldin; Goldman, Steven; Juneman, Elizabeth

2017-10-01

For chronic heart failure (CHF), more emphasis has been placed on evaluation of systolic as opposed to diastolic function. Within the study of diastology, measurements of left ventricular (LV) longitudinal myocardial relaxation have the most validation. Anterior wall radial myocardial tissue relaxation velocities along with mitral valve inflow (MVI) patterns are applicable diastolic parameters in the differentiation between moderate and severe disease in the ischemic rat model of CHF. Myocardial tissue relaxation velocities correlate with traditional measurements of diastolic function (ie, hemodynamics, Tau, and diastolic pressure-volume relationships). Male Sprague-Dawley rats underwent left coronary artery ligation or sham operation. Echocardiography was performed at 3 and 6 weeks after coronary ligation to evaluate LV ejection fraction (EF) and LV diastolic function through MVI patterns (E, A, and E/A) and Doppler imaging of the anterior wall (e' and a'). The rats were categorized into moderate or severe CHF according to their LV EF at 3 weeks postligation. Invasive hemodynamic measurements with solid-state pressure catheters were obtained at the 6-week endpoint. Moderate (N = 20) and severe CHF (N = 22) rats had significantly (P < .05) different EFs, hemodynamics, and diastolic pressure-volume relationships. Early diastolic anterior wall radial relaxation velocities as well as E/e' ratios separated moderate from severe CHF and both diastolic parameters had strong correlations with invasive hemodynamic measurements of diastolic function. Radial anterior wall e' and E/e' can be used for serial assessment of diastolic function in rats with moderate and severe CHF. Copyright © 2017 Elsevier Inc. All rights reserved.

Use of non-selective beta blockers in cirrhosis: The evidence we need before closing (or not) the window

PubMed Central

La Mura, Vincenzo; Tosetti, Giulia; Primignani, Massimo; Salerno, Francesco

2015-01-01

Non selective beta blockers (NSBBs) are used in primary and secondary prophylaxis of portal hypertension-related bleeding in patients with cirrhosis. The efficacy of NSBBs treatment is predicted by hemodynamic response in term of reduction of the hepatic venous pressure gradient (HVPG) below 12 mmHg or at least 20% of the basal value. Nevertheless a relevant number of patients who do not achieve this HVPG reduction during NSBBs therapy do not bleed during follow up; this evidence suggests an additional non-hemodynamic advantage of NSBBs treatment to modify the natural history of cirrhosis. Recent studies have questioned the efficacy and safety of NSBBs in patients with advanced stage of liver disease characterized by refractory ascites and/or spontaneous bacterial peritonitis. These studies have suggested the existence of a defined and limited period to modify the natural history of cirrhosis by NSBBs: the “window hypothesis”. According with this hypothesis, patients with cirrhosis benefit from the use of NSBBs from the appearance of varices up to the development of an advanced stage of cirrhosis. Indeed, in patients with refractory ascites and/or spontaneous bacterial peritonitis the hemodynamic effects of NSBBs may expose to a high risk of further complications such as renal insufficiency and/or death. Methodological concerns and contrasting results counterbalance the evidence produced up to now on this issue and are the main topic of this editorial. PMID:25741132

[Hemodialysis in patients with chronic renal insufficiency].

PubMed

Canaud, Bernard; Leray-Moragués, Hélène; Chenine-Koualef, Leila; Patrier, Laure

2012-01-01

Hemodialysis is the most advanced form of artificial renal support. It ensures the survival of almost 2 million patients wordwide. Considerable progress has been made in recent years thanks to a better understanding of uremia, optimization of treatment modalities and more personalized treatment schedules. Increase of uremic toxins removal, improvement of hemodynamic tolerance of the sessions, reduction of proinflammatory reactions due to the bioincompatibility system are major advances that may explain the reduction of morbidity and mortality in dialysis patients. New technologies (nanotechnology, biotechnology, microelectronics) are now expected to introduce further progresses by miniaturizing devices and providing them with an "artificial intelligence" capable of interacting with the patient. The main obstacle remains ageing of uremic patients, increasing prevalence of comorbidities and shortage of social resources that are not conducive to innovation. By promoting a more physiological, longer and more effective hemodialysis performed at home with help of teledialysis monitoring that would probably be an interesting option to evaluate on a medico-economical point of view.

Effects of Clofibrate on Salt Loading-Induced Hypertension in Rats

PubMed Central

Cruz, Antonio; Rodríguez-Gómez, Isabel; Pérez-Abud, Rocío; Vargas, Miguel Ángel; Wangensteen, Rosemary; Quesada, Andrés; Osuna, Antonio; Moreno, Juan Manuel

2011-01-01

The effects of clofibrate on the hemodynamic and renal manifestations of increased saline intake were analyzed. Four groups of male Wistar rats were treated for five weeks: control, clofibrate (240 mg/kg/day), salt (2% via drinking water), and salt + clofibrate. Body weight, systolic blood pressure (SBP), and heart rate (HR) were recorded weekly. Finally, SBP, HR, and morphologic, metabolic, plasma, and renal variables were measured. Salt increased SBP, HR, urinary isoprostanes, NOx, ET, vasopressin and proteinuria and reduced plasma free T4 (FT4) and tissue FT4 and FT3 versus control rats. Clofibrate prevented the increase in SBP produced by salt administration, reduced the sodium balance, and further reduced plasma and tissue thyroid hormone levels. However, clofibrate did not modify the relative cardiac mass, NOx, urinary ET, and vasopressin of saline-loaded rats. In conclusion, chronic clofibrate administration prevented the blood pressure elevation of salt-loaded rats by decreasing sodium balance and reducing thyroid hormone levels. PMID:20981147

Zolmitriptan: a novel portal hypotensive agent which synergizes with propranolol in lowering portal pressure.

PubMed

Reboredo, Mercedes; Chang, Haisul C Y; Barbero, Roberto; Rodríguez-Ortigosa, Carlos M; Pérez-Vizcaíno, Francisco; Morán, Asunción; García, Mónica; Banales, Jesús M; Carreño, Norberto; Alegre, Félix; Herrero, Ignacio; Quiroga, Jorge; Prieto, Jesús; Sangro, Bruno

2013-01-01

Only a limited proportion of patients needing pharmacological control of portal hypertension are hemodynamic responders to propranolol. Here we analyzed the effects of zolmitriptan on portal pressure and its potential interaction with propranolol. ZOLMITRIPTAN, PROPRANOLOL OR BOTH WERE TESTED IN TWO RAT MODELS OF PORTAL HYPERTENSION: common bile duct ligation (CBDL) and CCl4-induced cirrhosis. In these animals we measured different hemodynamic parameters including portal venous pressure, arterial renal flow, portal blood flow and cardiac output. We also studied the changes in superior mesenteric artery perfusion pressure and in arterial wall cAMP levels induced by zolmitriptan, propranolol or both. Moreover, we determined the effect of splanchnic sympathectomy on the response of PVP to zolmitriptan. In both models of portal hypertension zolmitriptan induced a dose-dependent transient descent of portal pressure accompanied by reduction of portal flow with only slight decrease in renal flow. In cirrhotic rats, splanchnic sympathectomy intensified and prolonged zolmitriptan-induced portal pressure descent. Also, propranolol caused more intense and durable portal pressure fall when combined with zolmitriptan. Mesenteric artery perfusion pressure peaked for about 1 min upon zolmitriptan administration but showed no change with propranolol. However propranolol enhanced and prolonged the elevation in mesenteric artery perfusion pressure induced by zolmitriptan. In vitro studies showed that propranolol prevented the inhibitory effects of β2-agonists on zolmitriptan-induced vasoconstriction and the combination of propranolol and zolmitriptan significantly reduced the elevation of cAMP caused by β2-agonists. Zolmitriptan reduces portal hypertension and non-selective beta-blockers can improve this effect. Combination therapy deserves consideration for patients with portal hypertension failing to respond to non-selective beta-blockers.

The Prognostic Importance of Changes in Renal Function during Treatment for Acute Heart Failure Depends on Admission Renal Function

PubMed Central

Reid, Ryan; Ezekowitz, Justin A.; Brown, Paul M.; McAlister, Finlay A.; Rowe, Brian H.; Braam, Branko

2015-01-01

Background Worsening and improving renal function during acute heart failure have been associated with adverse outcomes but few studies have considered the admission level of renal function upon which these changes are superimposed. Objectives The objective of this study was to evaluate definitions that incorporate both admission renal function and change in renal function. Methods 696 patients with acute heart failure with calculable eGFR were classified by admission renal function (Reduced [R, eGFR<45 ml/min] or Preserved [P, eGFR≥45 ml/min]) and change over hospital admission (worsening [WRF]: eGFR ≥20% decline; stable [SRF]; and improving [IRF]: eGFR ≥20% increase). The primary outcome was all-cause mortality. The prevalence of Pres and Red renal function was 47.8% and 52.2%. The frequency of R-WRF, R-SRF, and R-IRF was 11.4%, 28.7%, and 12.1%, respectively; the incidence of P-WRF, P-SRF, and P-IRF was 5.7%, 35.3%, and 6.8%, respectively. Survival was shorter for patients with R-WRF compared to R-IRF (median survival times 13.9 months (95%CI 7.7–24.9) and 32.5 months (95%CI 18.8–56.1), respectively), resulting in an acceleration factor of 2.3 (p = 0.016). Thus, an increase compared with a decrease in renal function was associated with greater than two times longer survival among patients with Reduced renal function. PMID:26380982

Nephrotoxicity of ibandronate and zoledronate in Wistar rats with normal renal function and after unilateral nephrectomy.

PubMed

Bergner, R; Siegrist, B; Gretz, N; Pohlmeyer-Esch, G; Kränzlin, B

2015-09-01

A previous animal study compared the nephrotoxic effect of ibandronate (IBN) and zoledronate (ZOL), but interpretation of these study results was limited because of the model of minimal nephrotoxic dosage with a dosage ratio of 1:3. The present study investigated the nephrotoxicity of ibandronate and zoledronate in a 1.5:1 dose ratio, as used in clinical practice and compared the nephrotoxicity in rats with normal and with mildly to moderately impaired renal function. We compared rats with normal renal function (SHAM) and with impaired renal function after unilateral nephrectomy (UNX), treated either with ibandronate 1.5mg/kg, zoledronate 1mg/kg or placebo once (1×) or nine (9×) times. Renal function and markers of tubular toxicity were measured over a 27 week period. After last bisphosphonate treatment the rats were sacrificed and kidneys examined histologically. All bisphosphonate treated animals showed a significant tubular toxicity, which was temporary except in the ZOL-UNX-9×-group. Also the renal function was only transiently reduced except in the ZOL-UNX-9×-group. Histologically, bisphosphonate treatment led to cortical tubuloepithelial degeneration/necrosis and medullary tubuloepithelial swelling which were slightly more pronounced in ibandronate treated animals, when compared to zoledronate treated animals, especially with impaired renal function. In contrast to the previous study we found a similar nephrotoxicity of ibandronate and zoledronate in rats with normal renal function. In rats with impaired renal function the peak of toxicity had not even been fully reached until end of experiment in the zoledronate treated animals. The peak of toxicity seems to be more severe and delayed in rats with impaired renal function compared with rats with normal renal function. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impaired renal function modifies the risk of severe hypoglycaemia among users of insulin but not glyburide: a population-based nested case-control study.

PubMed

Weir, Matthew A; Gomes, Tara; Mamdani, Muhammad; Juurlink, David N; Hackam, Daniel G; Mahon, Jeffrey L; Jain, Arsh K; Garg, Amit X

2011-06-01

Little evidence justifies the avoidance of glyburide in patients with impaired renal function. We aimed to determine if renal function modifies the risk of hypoglycaemia among patients using glyburide. We conducted a nested case-control study using administrative records and laboratory data from Ontario, Canada. We included outpatients 66 years of age and older with diabetes mellitus and prescriptions for glyburide, insulin or metformin. We ascertained hypoglycaemic events using administrative records and estimated glomerular filtration rates (eGFR) using serum creatinine concentrations. From a cohort of 19,620 patients, we identified 204 cases whose eGFR was ≥ 60 mL/min/1.73 m(2) (normal renal function) and 354 cases whose eGFR was < 60 mL/min/1.73 m(2) (impaired renal function). Compared to metformin, glyburide is associated with a greater risk of hypoglycaemia in patients with both normal [adjusted odds ratio (OR) 9.0, 95% confidence interval (95% CI) 4.9-16.4] and impaired renal function (adjusted OR 6.0, 95% CI 3.8-9.5). We observed a similar relationship when comparing insulin to metformin; the risk was greater in patients with normal renal function (adjusted OR 18.7, 95% CI 10.5-33.5) compared to those with impaired renal function (adjusted OR 7.9, 95% CI 5.0-12.4). Tests of interaction showed that among glyburide users, renal function did not significantly modify the risk of hypoglycaemia, but among insulin users, impaired renal function is associated with a lower risk. In this population-based study, impaired renal function did not augment the risk of hypoglycaemia associated with glyburide use.

A retrospective analysis of laparoscopic partial nephrectomy with segmental renal artery clamping and factors that predict postoperative renal function.

PubMed

Li, Pu; Qin, Chao; Cao, Qiang; Li, Jie; Lv, Qiang; Meng, Xiaoxin; Ju, Xiaobing; Tang, Lijun; Shao, Pengfei

2016-10-01

To evaluate the feasibility and efficiency of laparoscopic partial nephrectomy (LPN) with segmental renal artery clamping, and to analyse the factors affecting postoperative renal function. We conducted a retrospective analysis of 466 consecutive patients undergoing LPN using main renal artery clamping (group A, n = 152) or segmental artery clamping (group B, n = 314) between September 2007 and July 2015 in our department. Blood loss, operating time, warm ischaemia time (WIT) and renal function were compared between groups. Univariable and multivariable linear regression analyses were applied to assess the correlations of selected variables with postoperative glomerular filtration rate (GFR) reduction. Volumetric data and estimated GFR of a subset of 60 patients in group B were compared with GFR to evaluate the correlation between these functional variables and preserved renal function after LPN. The novel technique slightly increased operating time, WIT and intra-operative blood loss (P < 0.001), while it provided better postoperative renal function (P < 0.001) compared with the conventional technique. The blocking method and tumour characteristics were independent factors affecting GFR reduction, while WIT was not an independent factor. Correlation analysis showed that estimated GFR presented better correlation with GFR compared with kidney volume (R(2) = 0.794 cf. R(2) = 0.199) in predicting renal function after LPN. LPN with segmental artery clamping minimizes warm ischaemia injury and provides better early postoperative renal function compared with clamping the main renal artery. Kidney volume has a significantly inferior role compared with eGFR in predicting preserved renal function. © 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.

Functional MRI detects perfusion impairment in renal allografts with delayed graft function.

PubMed

Hueper, Katja; Gueler, Faikah; Bräsen, Jan Hinrich; Gutberlet, Marcel; Jang, Mi-Sun; Lehner, Frank; Richter, Nicolas; Hanke, Nils; Peperhove, Matti; Martirosian, Petros; Tewes, Susanne; Vo Chieu, Van Dai; Großhennig, Anika; Haller, Hermann; Wacker, Frank; Gwinner, Wilfried; Hartung, Dagmar

2015-06-15

Delayed graft function (DGF) after kidney transplantation is not uncommon, and it is associated with long-term allograft impairment. Our aim was to compare renal perfusion changes measured with noninvasive functional MRI in patients early after kidney transplantation to renal function and allograft histology in biopsy samples. Forty-six patients underwent MRI 4-11 days after transplantation. Contrast-free MRI renal perfusion images were acquired using an arterial spin labeling technique. Renal function was assessed by estimated glomerular filtration rate (eGFR), and renal biopsies were performed when indicated within 5 days of MRI. Twenty-six of 46 patients had DGF. Of these, nine patients had acute rejection (including borderline), and eight had other changes (e.g., tubular injury or glomerulosclerosis). Renal perfusion was significantly lower in the DGF group compared with the group with good allograft function (231 ± 15 vs. 331 ± 15 ml·min(-1)·100 g(-1), P < 0.001). Living donor allografts exhibited significantly higher perfusion values compared with deceased donor allografts (P < 0.001). Renal perfusion significantly correlated with eGFR (r = 0.64, P < 0.001), resistance index (r = -0.57, P < 0.001), and cold ischemia time (r = -0.48, P < 0.01). Furthermore, renal perfusion impairment early after transplantation predicted inferior renal outcome and graft loss. In conclusion, noninvasive functional MRI detects renal perfusion impairment early after kidney transplantation in patients with DGF. Copyright © 2015 the American Physiological Society.

Renal function monitoring in heart failure – what is the optimal frequency? A narrative review

PubMed Central

Wright, David; Devonald, Mark Alexander John; Pirmohamed, Munir

2017-01-01

The second most common cause of hospitalization due to adverse drug reactions in the UK is renal dysfunction due to diuretics, particularly in patients with heart failure, where diuretic therapy is a mainstay of treatment regimens. Therefore, the optimal frequency for monitoring renal function in these patients is an important consideration for preventing renal failure and hospitalization. This review looks at the current evidence for optimal monitoring practices of renal function in patients with heart failure according to national and international guidelines on the management of heart failure (AHA/NICE/ESC/SIGN). Current guidance of renal function monitoring is in large part based on expert opinion, with a lack of clinical studies that have specifically evaluated the optimal frequency of renal function monitoring in patients with heart failure. Furthermore, there is variability between guidelines, and recommendations are typically nonspecific. Safer prescribing of diuretics in combination with other antiheart failure treatments requires better evidence for frequency of renal function monitoring. We suggest developing more personalized monitoring rather than from the current medication‐based guidance. Such flexible clinical guidelines could be implemented using intelligent clinical decision support systems. Personalized renal function monitoring would be more effective in preventing renal decline, rather than reacting to it. PMID:28901643

High Prolactin Excretion in Patients with Diabetes Mellitus and Impaired Renal Function.

PubMed

Triebel, Jakob; Moreno-Vega, Aura Ileana; Vázquez-Membrillo, Miguel; Nava, Gabriel; García-Franco, Renata; López-Star, Ellery; Baldivieso-Hurtado, Olivia; Ochoa, Daniel; Macotela, Yazmín; Bertsch, Thomas; Martinez de la Escalera, Gonzalo; Clapp, Carmen

2015-01-01

The metabolic clearance of prolactin (PRL) is partially executed by the kidney. Here, we investigate the urine excretion of PRL in patients with Diabetes Mellitus and renal impairment. Serum and urine samples were collected from male, mestizo patients in central Mexico employing a cross-sectional study design. Ninety-eight individuals had either no diabetes and normal renal function (control), diabetes and normal renal function, or diabetes with impaired renal function. PRL was determined by a chemiluminescent immunometric assay; protein, albumin, and creatinine were evaluated using quantitative colorimetric assays. The results were analyzed using ANOVA-testing. Patients with Diabetes Mellitus and renal impairment had significantly higher urine PRL levels than patients with Diabetes Mellitus and normal renal function and control patients. Higher urine PRL levels were associated with lower glomerular filtration rates, higher serum creatinine, and higher urinary albumin-to-creatinine ratios (UACR). Urine PRL levels correlated positively with UACR. Serum PRL levels were similar among groups. Patients with Diabetes Mellitus and impaired renal function demonstrate a high urinary PRL excretion. Urinary PRL excretion in the context of proteinuria could contribute to PRL dysregulation in renal impairment.

Early fluid loading for septic patients: Any safety limit needed?

PubMed

Gong, Yi-Chun; Liu, Jing-Tao; Ma, Peng-Lin

2018-02-01

Early adequate fluid loading was the corner stone of hemodynamic optimization for sepsis and septic shock. Meanwhile, recent recommended protocol for fluid resuscitation was increasingly debated on hemodynamic stability vs risk of overloading. In recent publications, it was found that a priority was often given to hemodynamic stability rather than organ function alternation in the early fluid resuscitation of sepsis. However, no safety limits were used at all in most of these reports. In this article, the rationality and safety of early aggressive fluid loading for septic patients were discussed. It was concluded that early aggressive fluid loading improved hemodynamics transitorily, but was probably traded off with a follow-up organ function impairment, such as worsening oxygenation by reduction of lung aeration, in a part of septic patients at least. Thus, a safeguard is needed against unnecessary excessive fluids in early aggressive fluid loading for septic patients. Copyright © 2017 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Loss of vagal tone aggravates systemic inflammation and cardiac impairment in endotoxemic rats.

PubMed

Schulte, Astrid; Lichtenstern, Christoph; Henrich, Michael; Weigand, Markus A; Uhle, Florian

2014-05-15

During the course of sepsis, often myocardial depression with hemodynamic impairment occurs. Acetylcholine, the main transmitter of the parasympathetic Nervus vagus, has been shown to be of importance for the transmission of signals within the immune system and also for a variety of other functions throughout the organism. Hypothesizing a potential correlation between this dysfunction and hemodynamic impairment, we wanted to assess the impact of vagal stimulation on myocardial inflammation and function in a rat model of lipopolysaccharide (LPS)-induced septic shock. As the myocardial tissue is (sparsely) innervated by the N. vagus, there might be an important anti-inflammatory effect in the heart, inhibiting proinflammatory gene expression in cardiomyocytes and improving cardiac function. We performed stimulation of the right cervical branch of the N. vagus in vagotomized, endotoxemic (1 mg/kg body weight LPS, intravenously) rats. Hemodynamic parameters were assessed over time using a left ventricular pressure-volume catheter. After the experiments, hearts and blood plasma were collected, and the expression of proinflammatory cytokines was measured using quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. After vagotomy, the inflammatory response was aggravated, measurable by elevated cytokine levels in plasma and ventricular tissue. In concordance, cardiac impairment during septic shock was pronounced in these animals. To reverse both hemodynamic and immunologic effects of diminished vagal tone, even a brief stimulation of the N. vagus was enough during initial LPS infusion. Overall, the N. vagus might play a major role in maintaining hemodynamic stability and cardiac immune homeostasis during septic shock. Copyright © 2014 Elsevier Inc. All rights reserved.

Noninvasive optical evaluation of low frequency oscillations in prefrontal cortex hemodynamics during verbal working memory

NASA Astrophysics Data System (ADS)

Li, Ting; Zhao, Yue; Li, Kai; Sun, Yunlong

2014-03-01

The low frequency oscillation (LFO) around 0.1 Hz has been observed recently in cerebral hemodynamic signals during rest/sleep, enhanced breathing, and head- up-tilting, showing that cerebral autoregulation can be accessed by LFOs. However, many brain function researches require direct measurement of LFOs during specified brain function activities. This pilot study explored using near-infrared spectroscopy/imaging (NIRS) to noninvasively and simultaneously detect LFOs of prefrontal cerebral hemodynamics (i.e., oxygenated/deoxygenated/total hemoglobin concentration: △[oxy-Hb]/ △[deoxy-Hb]/ △[tot-Hb]) during N-back visual verbal working memory task. The LFOs were extracted from the measured variables using power spectral analysis. We found the brain activation sites struck clear LFOs while other sites did not. The LFO of △[deoxy-Hb] acted as a negative pike and ranged in (0.05, 0.1) Hz, while LFOs of △[oxy-Hb] and △[tot-Hb] acted as a positive pike and ranged in (0.1, 0.15) Hz. The amplitude difference and frequency lag between △[deoxy-Hb] and △[oxy-Hb]/ △[tot-Hb] produced a more focused and sensitive activation map compare to hemodynamic amplitude-quantified activation maps. This study observed LFOs in brain activities and showed strong potential of LFOs in accessing brain functions.

Vascular Adaptation to Exercise in Humans: Role of Hemodynamic Stimuli

PubMed Central

Green, Daniel J.; Hopman, Maria T. E.; Padilla, Jaume; Laughlin, M. Harold; Thijssen, Dick H. J.

2017-01-01

On the 400th anniversary of Harvey's Lumleian lectures, this review focuses on “hemodynamic” forces associated with the movement of blood through arteries in humans and the functional and structural adaptations that result from repeated episodic exposure to such stimuli. The late 20th century discovery that endothelial cells modify arterial tone via paracrine transduction provoked studies exploring the direct mechanical effects of blood flow and pressure on vascular function and adaptation in vivo. In this review, we address the impact of distinct hemodynamic signals that occur in response to exercise, the interrelationships between these signals, the nature of the adaptive responses that manifest under different physiological conditions, and the implications for human health. Exercise modifies blood flow, luminal shear stress, arterial pressure, and tangential wall stress, all of which can transduce changes in arterial function, diameter, and wall thickness. There are important clinical implications of the adaptation that occurs as a consequence of repeated hemodynamic stimulation associated with exercise training in humans, including impacts on atherosclerotic risk in conduit arteries, the control of blood pressure in resistance vessels, oxygen delivery and diffusion, and microvascular health. Exercise training studies have demonstrated that direct hemodynamic impacts on the health of the artery wall contribute to the well-established decrease in cardiovascular risk attributed to physical activity. PMID:28151424

Effect of confounding variables on hemodynamic response function estimation using averaging and deconvolution analysis: An event-related NIRS study.

PubMed

Aarabi, Ardalan; Osharina, Victoria; Wallois, Fabrice

2017-07-15

Slow and rapid event-related designs are used in fMRI and functional near-infrared spectroscopy (fNIRS) experiments to temporally characterize the brain hemodynamic response to discrete events. Conventional averaging (CA) and the deconvolution method (DM) are the two techniques commonly used to estimate the Hemodynamic Response Function (HRF) profile in event-related designs. In this study, we conducted a series of simulations using synthetic and real NIRS data to examine the effect of the main confounding factors, including event sequence timing parameters, different types of noise, signal-to-noise ratio (SNR), temporal autocorrelation and temporal filtering on the performance of these techniques in slow and rapid event-related designs. We also compared systematic errors in the estimates of the fitted HRF amplitude, latency and duration for both techniques. We further compared the performance of deconvolution methods based on Finite Impulse Response (FIR) basis functions and gamma basis sets. Our results demonstrate that DM was much less sensitive to confounding factors than CA. Event timing was the main parameter largely affecting the accuracy of CA. In slow event-related designs, deconvolution methods provided similar results to those obtained by CA. In rapid event-related designs, our results showed that DM outperformed CA for all SNR, especially above -5 dB regardless of the event sequence timing and the dynamics of background NIRS activity. Our results also show that periodic low-frequency systemic hemodynamic fluctuations as well as phase-locked noise can markedly obscure hemodynamic evoked responses. Temporal autocorrelation also affected the performance of both techniques by inducing distortions in the time profile of the estimated hemodynamic response with inflated t-statistics, especially at low SNRs. We also found that high-pass temporal filtering could substantially affect the performance of both techniques by removing the low-frequency components of HRF profiles. Our results emphasize the importance of characterization of event timing, background noise and SNR when estimating HRF profiles using CA and DM in event-related designs. Copyright © 2017 Elsevier Inc. All rights reserved.

Efficacy and Safety of Apixaban Compared With Warfarin in Patients With Atrial Fibrillation in Relation to Renal Function Over Time: Insights From the ARISTOTLE Randomized Clinical Trial.

PubMed

Hijazi, Ziad; Hohnloser, Stefan H; Andersson, Ulrika; Alexander, John H; Hanna, Michael; Keltai, Matyas; Parkhomenko, Alexander; López-Sendón, José L; Lopes, Renato D; Siegbahn, Agneta; Granger, Christopher B; Wallentin, Lars

2016-07-01

Renal impairment confers an increased risk of stroke, bleeding, and death in patients with atrial fibrillation. Little is known about the efficacy and safety of apixaban in relation to renal function changes over time. To evaluate changes of renal function over time and their interactions with outcomes during a median of 1.8 years of follow-up in patients with atrial fibrillation randomized to apixaban vs warfarin treatment. The prospective, randomized, double-blind Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) clinical trial randomized 18 201 patients with atrial fibrillation to apixaban or warfarin. Serial creatinine measurements were available in 16 869 patients. Worsening of renal function was defined as an annual decrease in estimated glomerular filtration more than 20%. The relations between treatment, outcomes, and renal function were investigated using Cox regression models, with renal function as a time-dependent covariate. Stroke or systemic embolism (primary outcome), major bleeding (safety outcome), and mortality were examined in relation to renal function over time estimated with both the Cockcroft-Gault and Chronic Kidney Disease Epidemiology Collaboration equations. Among 16 869 patients, the median age was 70 years and 65.2% of patients were men. Worsening in estimated glomerular filtration more than 20% was observed in 2294 patients (13.6%) and was associated with older age and more cardiovascular comorbidities. The risks of stroke or systemic embolism, major bleeding, and mortality were higher in patients with worsening renal function (HR, 1.53; 95% CI, 1.17-2.01 for stroke or systemic embolism; HR, 1.56; 95% CI, 1.27-1.93 for major bleeding; and HR, 2.31; 95% CI, 1.98-2.68 for mortality). The beneficial effects of apixaban vs warfarin on rates of stroke or systemic embolism and major bleeding were consistent in patients with normal or poor renal function over time and also in those with worsening renal function. In patients with atrial fibrillation, declining renal function was more common in elderly patients and those with cardiovascular comorbidities. Worsening renal function was associated with a higher risk of subsequent cardiovascular events and bleeding. The superior efficacy and safety of apixaban as compared with warfarin were similar in patients with normal, poor, and worsening renal function. clinicaltrials.gov Identifier: NCT00412984.

Iohexol clearance is superior to creatinine-based renal function estimating equations in detecting short-term renal function decline in chronic heart failure

PubMed Central

Cvan Trobec, Katja; Kerec Kos, Mojca; von Haehling, Stephan; Anker, Stefan D.; Macdougall, Iain C.; Ponikowski, Piotr; Lainscak, Mitja

2015-01-01

Aim To compare the performance of iohexol plasma clearance and creatinine-based renal function estimating equations in monitoring longitudinal renal function changes in chronic heart failure (CHF) patients, and to assess the effects of body composition on the equation performance. Methods Iohexol plasma clearance was measured in 43 CHF patients at baseline and after at least 6 months. Simultaneously, renal function was estimated with five creatinine-based equations (four- and six-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Cockcroft-Gault adjusted for lean body mass, Chronic Kidney Disease Epidemiology Collaboration equation) and body composition was assessed using bioimpedance and dual-energy x-ray absorptiometry. Results Over a median follow-up of 7.5 months (range 6-17 months), iohexol clearance significantly declined (52.8 vs 44.4 mL/[min ×1.73 m2], P = 0.001). This decline was significantly higher in patients receiving mineralocorticoid receptor antagonists at baseline (mean decline -22% of baseline value vs -3%, P = 0.037). Mean serum creatinine concentration did not change significantly during follow-up and no creatinine-based renal function estimating equation was able to detect the significant longitudinal decline of renal function determined by iohexol clearance. After accounting for body composition, the accuracy of the equations improved, but not their ability to detect renal function decline. Conclusions Renal function measured with iohexol plasma clearance showed relevant decline in CHF patients, particularly in those treated with mineralocorticoid receptor antagonists. None of the equations for renal function estimation was able to detect these changes. ClinicalTrials.gov registration number NCT01829880 PMID:26718759

Renal Function Recovery with Total Artificial Heart Support.

PubMed

Quader, Mohammed A; Goodreau, Adam M; Shah, Keyur B; Katlaps, Gundars; Cooke, Richard; Smallfield, Melissa C; Tchoukina, Inna F; Wolfe, Luke G; Kasirajan, Vigneshwar

2016-01-01

Heart failure patients requiring total artificial heart (TAH) support often have concomitant renal insufficiency (RI). We sought to quantify renal function recovery in patients supported with TAH at our institution. Renal function data at 30, 90, and 180 days after TAH implantation were analyzed for patients with RI, defined as hemodialysis supported or an estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73 m. Between January 2008 and December 2013, 20 of the 46 (43.5%) TAH recipients (age 51 ± 9 years, 85% men) had RI, mean preoperative eGFR of 48 ± 7 ml/min/1.73 m. Renal function recovery was noted at each follow-up interval: increment in eGFR (ml/min/1.73 m) at 30, 90, and 180 days was 21 ± 35 (p = 0.1), 16.5 ± 18 (p = 0.05), and 10 ± 9 (p = 0.1), respectively. Six patients (30%) required preoperative dialysis. Of these, four recovered renal function, one remained on dialysis, and one died. Six patients (30%) required new-onset dialysis. Of these, three recovered renal function and three died. Overall, 75% (15 of 20) of patients' renal function improved with TAH support. Total artificial heart support improved renal function in 75% of patients with pre-existing significant RI, including those who required preoperative dialysis.

Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform

PubMed Central

Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang; Tsai, Tung-Hu; Chang, Hen-Hong

2016-01-01

We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features. PMID:27304979

Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform.

PubMed

Wu, Hau-Tieng; Wu, Han-Kuei; Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang; Tsai, Tung-Hu; Chang, Hen-Hong

2016-01-01

We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features.

A Comparison Between the Hemodynamic Effects of Cisatracurium and Atracurium in Patient with Low Function of Left Ventricle who are Candidate for Open Heart Surgery.

PubMed

Ghorbanlo, Masoud; Mohaghegh, Mahmoud Reza; Yazdanian, Forozan; Mesbah, Mehrdad; Totonchi, Ziya

2016-07-27

The need for muscle relaxants in general anesthesia in different surgeries including cardiac surgeries, and the type of relaxant to be used considering its different hemodynamic effects on patients with heart disease can be of considerable importance. In this study, the hemodynamic effects of two muscle relaxants, Cisatracurium and Atracurium in patients whit low function of left ventricle who are candidate for open heart surgery have been considered. This study has been designed as a randomized prospective double-blind clinical trial. The target population included all adult patients with heart disease whose ejection fraction reported by echocardiography or cardiac catheterization was 35% or less before the surgery, and were candidate for open heart surgery in Shahid Rajaei Heart Center. Taking into account the inclusion and exclusion criteria, the patients were randomly placed in two groups of 30 people each. In the induction stage, all the patients received midazolam, etomidate, and one of the considered muscle relaxant, either 0.2 mg/kg of cisatracurium or 0.5mg/kg of Atracurium within one minute. In the maintenance stage of anesthesia, the patients were administered by infusion of midazolam, sufentanil and the same muscle relaxant used in the induction stage. The hemodynamic indexes were recorded and evaluated in different stages of anesthesia and surgery as well as prior to transfer to ICU. In regard with descriptive indexes (age and sex distributions, premedication with cardiac drugs, ejection fraction before surgery, basic disease) there was no statistically significant difference between the groups. The significant difference of hemodynamic indexes between the two groups of this study, and the need for hemodynamic stability in all stages of surgery for patients with low function of left ventricle who are candidate for open heart surgery, proves that administering Cisatracurium as the muscle relaxant is advantageous and better.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wehrschuetz, M., E-mail: martin.wehrschuetz@klinikum-graz.at; Aschauer, M.; Portugaller, H.

The purpose of this study was to assess interobserver variability and accuracy in the evaluation of renal artery stenosis (RAS) with gadolinium-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in patients with hypertension. The authors found that source images are more accurate than maximum intensity projection (MIP) for depicting renal artery stenosis. Two independent radiologists reviewed MRA and DSA from 38 patients with hypertension. Studies were postprocessed to display images in MIP and source images. DSA was the standard for comparison in each patient. For each main renal artery, percentage stenosis was estimated for any stenosis detected by themore » two radiologists. To calculate sensitivity, specificity and accuracy, MRA studies and stenoses were categorized as normal, mild (1-39%), moderate (40-69%) or severe ({>=}70%), or occluded. DSA stenosis estimates of 70% or greater were considered hemodynamically significant. Analysis of variance demonstrated that MIP estimates of stenosis were greater than source image estimates for both readers. Differences in estimates for MIP versus DSA reached significance in one reader. The interobserver variance for MIP, source images and DSA was excellent (0.80< {kappa}{<=} 0.90). The specificity of source images was high (97%) but less for MIP (87%); average accuracy was 92% for MIP and 98% for source images. In this study, source images are significantly more accurate than MIP images in one reader with a similar trend was observed in the second reader. The interobserver variability was excellent. When renal artery stenosis is a consideration, high accuracy can only be obtained when source images are examined.« less

Current Management of Calcific Aortic Stenosis

PubMed Central

Lindman, Brian R.; Bonow, Robert O.; Otto, Catherine M.

2014-01-01

Calcific aortic stenosis (AS) is a progressive disease with no effective medical therapy that ultimately requires aortic valve replacement (AVR) for severe valve obstruction. Echocardiography is the primary diagnostic approach to define valve anatomy, measure AS severity and evaluate the left ventricular (LV) response to chronic pressure overload. In asymptomatic patients, markers of disease progression include the degree of leaflet calcification, hemodynamic severity of stenosis, adverse LV remodeling, reduced LV longitudinal strain, myocardial fibrosis and pulmonary hypertension. The onset of symptoms portends a predictably high mortality rate unless AVR is performed. In symptomatic patients, AVR improves symptoms, improves survival and, in patients with LV dysfunction, improves systolic function. Poor outcomes after AVR are associated with low-flow low-gradient AS, severe ventricular fibrosis, oxygen dependent lung disease, frailty, advanced renal dysfunction and a high comorbidity score. However, in most patients with severe symptoms, AVR is lifesaving. Bioprosthetic valves are recommended for patients over the age of 65 years. Transcatheter AVR is now available for patients with severe comorbidities, is recommended in patients who are deemed inoperable and is a reasonable alternative to surgical AVR in high risk patients. PMID:23833296

Simplified technique for auxiliary orthotopic liver transplantation using a whole graft

PubMed Central

ROCHA-SANTOS, Vinicius; NACIF, Lucas Souto; PINHEIRO, Rafael Soares; DUCATTI, Liliana; ANDRAUS, Wellington; D'ALBURQUERQUE, Luiz Carneiro

2015-01-01

Background Acute liver failure is associated with a high mortality rate and the main purposes of treatment are to prevent cerebral edema and infections, which often are responsible for patient death. The orthotopic liver transplantation is the gold standard treatment and improves the 1-year survival. Aim To describe an alternative technique to auxiliary liver transplant on acute liver failure. Method Was performed whole auxiliary liver transplantation as an alternative technique for a partial auxiliary liver transplantation using a whole liver graft from a child removing the native right liver performed a right hepatectomy. The patient met the O´Grady´s criteria and the rational to indicate an auxiliary orthotopic liver transplantation was the acute classification without hemodynamic instability or renal failure in a patient with deterioration in consciousness. Results The procedure improved liver function and decreased intracranial hypertension in the postoperative period. Conclusion This technique can overcome some postoperative complications that are associated with partial grafts. As far as is known, this is the first case of auxiliary orthotopic liver transplantation in Brazil. PMID:26176253

Effects of pimobendan for mitral valve regurgitation in dogs.

PubMed

Kanno, Nobuyuki; Kuse, Hiroshi; Kawasaki, Masaya; Hara, Akashi; Kano, Rui; Sasaki, Yoshihide

2007-04-01

Pimobendan has a dual mechanism of action: it increases myocardial contractility by increasing calcium sensitization to troponin C and it promotes vasodilation by inhibiting PDEIII. This study examined the effects of pimobendan on cardiac function, hemodynamics, and neurohormonal factors in dogs with mild mitral regurgitation (MR). The dogs were given 0.25 mg/kg of pimobendan orally every 12 hr for 4 weeks. With pimobendan, the heart rate and stroke volume did not change, but the systolic blood pressure gradually decreased and the degree of mitral valve regurgitation tended to decrease. Renal blood flow was significantly increased and the glomerular filtration rate was slightly increased at 2 and 4 weeks. Furthermore, over the 4-week period, the plasma norepinephrine concentration decreased significantly, the systolic index increased slightly, the left atrial diameter and the left ventricular diameters decreased significantly, and the heart size improved. Given these results, pimobendan appears to be useful for treating MR in dogs. However, further long-term studies of pimobendan involving a larger number of dogs with mild and moderate MR are needed to establish the safety of pimobendan and document improvements in quality of life.

Pathophysiology and management of pediatric ascites.

PubMed

Sabri, Mahmoud; Saps, Miguel; Peters, John M

2003-06-01

Ascites accumulation is the product of a complex process involving hepatic, renal, systemic, hemodynamic, and neurohormonal factors. The main pathophysiologic theories of ascites formation include the "underfill," "overflow," and peripheral arterial vasodilation hypotheses. These theories are not necessarily mutually exclusive and are linked at some level by a common pathophysiologic thread: The body senses a decreased effective arterial blood volume, leading to stimulation of the sympathetic nervous system, arginine-vasopressin feedback loops, and the renin-angiotensin-aldosterone system. Cornerstones of ascites management include dietary sodium restriction and diuretics. Spironolactone is generally tried initially, with furosemide added if clinical response is suboptimal. More refractory patients require large-volume paracentesis (LVP) accompanied by volume expansion with albumin. Placement of a transjugular intrahepatic portosystemic shunt is reserved for individuals with compensated liver function who require very frequent sessions of LVP. Peritoneovenous shunts are not used in contemporary ascites management. Liver transplantation remains the definitive therapy for refractory ascites. Although treatment of ascites fails to improve survival, it benefits quality of life and limits the development of such complications as spontaneous bacterial peritonitis.

Improvement in Renal Function and Symptoms of Patients Treated with Laparoscopic Pyeloplasty for Ureteropelvic Junction Obstruction with Less Than 20% Split Renal Function.

PubMed

Nishi, Morihiro; Matsumoto, Kazumasa; Fujita, Tetsuo; Iwamura, Masatsugu

2016-11-01

To evaluate the efficacy of laparoscopic pyeloplasty (LPP) for lower functioning kidney, we investigated the outcome of this procedure for patients with ureteropelvic junction obstruction with decreased renal function, defined as less than 20% split renal function. Between October 1998 and June 2015, we performed transperitoneal dismembered LPP in 224 patients. Among them, 15 patients with less than 20% split renal function were included in this study. Patient characteristics, perioperative split renal functions, complications, and surgical outcomes were retrospectively investigated. Fourteen of 15 patients had preoperative symptoms, including flank pain in 13 patients and gross hematuria in 1 patient. Preoperative 99mTc-mercaptoacetyltriglycine (MAG3) renogram revealed no response to diuretic injection and median split renal function was 16.5%. Median operative time and blood loss were 170 minutes and 20 mL, respectively. There were no complications during the perioperative period. Postoperative MAG3 renogram at 6 and 12 months after the operation revealed significantly increased split renal function (median: 23.8% and 23.7%, p = 0.001 and 0.008, respectively) and response to diuretic injection in all patients. Preoperative symptoms disappeared and no recurrence was seen during the follow-up period for all patients except for one who experienced flank pain again 4 months after the surgery. He subsequently underwent open pyeloplasty, and flank pain disappeared soon after. LPP for patients with low split renal function and flank pain significantly improved symptoms and split renal functions. Although the long-term clinical effects of LPP are unknown, we recommend performing LPP before considering nephrectomy for patients with lower functioning kidney.

Successful treatment of thyroid storm presenting as recurrent cardiac arrest and subsequent multiorgan failure by continuous renal replacement therapy.

PubMed

Park, Han Soo; Kwon, Su Kyoung; Kim, Ye Na

2017-01-01

Thyroid storm is a rare and potentially life-threatening medical emergency. We experienced a case of thyroid storm associated with sepsis caused by pneumonia, which had a catastrophic course including recurrent cardiac arrest and subsequent multiple organ failure (MOF). A 22-year-old female patient with a 10-year history of Graves' disease was transferred to our emergency department (ED). She had a cardiac arrest at her home and a second cardiac arrest at the ED. Her heart recovered after 20 min of cardiac resuscitation. She was diagnosed with thyroid storm associated with hyperthyroidism complicated by pneumonia and sepsis. Although full conventional medical treatment was given, she had progressive MOF and hemodynamic instability consisting of hyperthermia, tachycardia and hypotension. Because of hepatic and renal failure with refractory hypotension, we reduced the patient's dose of beta-blocker and antithyroid drug, and she was started on continuous veno-venous renal replacement therapy (CRRT) with intravenous albumin and plasma supplementation. Subsequently, her body temperature and pulse rate began to stabilize within 1 h, and her blood pressure reached 120/60 mmHg after 6 h. We discontinued antithyroid drug 3 days after admission because of aggravated hyperbilirubinemia. The patient exhibited progressive improvement in thyroid function even after cessation of antithyroid drug, and she successfully recovered from thyroid storm and MOF. This is the first case of thyroid storm successfully treated by CRRT in a patient considered unfit for antithyroid drug treatment. The presenting manifestations of thyroid storm vary and can include cardiac arrest with multiorgan failure in rare cases.In some patients with thyroid storm, especially those with severe complications, conventional medical treatment may be ineffective or inappropriate.During thyroid storm, the initiation of CRRT can immediately lower body temperature and subsequently stabilize vital signs.Early initiation of CRRT can be life-saving in patients with thyroid storm complicated by MOF, even when used in combination with suboptimal medical treatment.

Renal function had an independent relationship with coronary artery calcification in Chinese elderly men.

PubMed

Fu, Shihui; Zhang, Zhao; Luo, Leiming; Ye, Ping

2017-04-07

Although previous studies have analyzed the relationship between renal function and coronary artery calcification (CAC) in pre-dialysis and dialysis patients, limited studies have discussed the relationship between renal function and CAC in Chinese elderly men without obvious damage of renal function. The present study was designed to explore the relationship between renal function and CAC in Chinese elderly men without obvious damage of renal function. This cross-sectional study was carried out in 105 male participants older than 60 years with glomerular filtration rate (GFR) ≥ 45 ml/min/1.73 m 2 . CAC was detected by high-definition computerized tomography (HDCT), which is a highly sensitive technique for detecting the CAC and provides the most accurate CAC scores up to date. Age was 72 ± 8.4 years on average and ranged from 60 to 89 years. Simple correlation analysis indicated that all kinds of CAC scores including the Agatston, volume and mass scores inversely correlated with GFR values (p < 0.05 for all). In multivariate linear regression analysis, GFR values were independently associated with all these CAC scores (p < 0.05 for all). Renal function had an independent relationship with CAC detected by HDCT in Chinese elderly men, demonstrating that the relationship between renal function and CAC started at the early stage of renal function decline.

WWSSF - a worldwide study on radioisotopic renal split function: reproducibility of renal split function assessment in children.

PubMed

Geist, Barbara Katharina; Dobrozemsky, Georg; Samal, Martin; Schaffarich, Michael P; Sinzinger, Helmut; Staudenherz, Anton

2015-12-01

The split or differential renal function is the most widely accepted quantitative parameter derived from radionuclide renography. To examine the intercenter variance of this parameter, we designed a worldwide round robin test. Five selected dynamic renal studies have been distributed all over the world by e-mail. Three of these studies are anonymized patient data acquired using the EANM standardized protocol and two studies are phantom studies. In a simple form, individual participants were asked to measure renal split function as well as to provide additional information such as data analysis software, positioning of background region of interest, or the method of calculation. We received the evaluation forms from 34 centers located in 21 countries. The analysis of the round robin test yielded an overall z-score of 0.3 (a z-score below 1 reflecting a good result). However, the z-scores from several centers were unacceptably high, with values greater than 3. In particular, the studies with impaired renal function showed a wide variance. A wide variance in the split renal function was found in patients with impaired kidney function. This study indicates the ultimate importance of quality control and standardization of the measurement of the split renal function. It is especially important with respect to the commonly accepted threshold for significant change in split renal function by 10%.

Metal accumulation and nephron heterogeneity in mercuric chloride-induced acute renal failure.

PubMed

Wilks, M F; Gregg, N J; Bach, P H

1994-01-01

The present study was designed to assess the effects of mercury on glomerular integrity during the early phase of acute renal failure. The silver amplification method showed distribution of mercury in midcortical and juxtamedullary glomeruli and on the brush border of the S2 segment of the proximal tubule 15 min after treatment. At 30 min, there was a decrease in glomerular staining and increased mercury in the proximal tubule. After 3 hr, mercury was no longer detectable in glomeruli but was widespread in the lumen of the proximal tubule. By 24 hr, mercury was prominent in all proximal tubular segments throughout the cortex. The presence of mercury in glomeruli was not related to hemodynamic changes, as there was no evidence for blood redistribution toward juxtamedullary glomeruli as assessed by the filling of the microvascular system with Monastral Blue B. The reduced activity of horseradish peroxidase (administered i.v. 90 sec and 10 min before sacrifice) in juxtamedullary glomeruli 30 min after mercury administration suggests a decreased uptake of horseradish peroxidase or an increased glomerular protein filtration. These data support glomerular filtration as the predominant excretory route for mercury, highlight the marked nephron heterogeneity in the distribution of this metal, and show that impairment of glomerular integrity occurs before necrosis of the proximal tubules and acute renal failure.

Renal hemodynamic response to galanin: importance of elevated plasma glucose.

PubMed

Premen, A J

1989-12-01

Although recent data point to a possible indirect role for galanin in modulating renal blood flow (RBF) and fluid homeostasis in experimental animals, there have been no systematic studies exploring the possible direct effects of the peptide on the mammalian kidney. We ascertained the RBF, glomerular filtration rate (GFR) and plasma glucose responses to direct intrarenal infusion of three progressively increasing doses of synthetic galanin in anesthetized dogs. A 50 ng/kg per min dose (n = 6) failed to affect RBF, GFR or arterial plasma glucose (APG). Yet, a 100 ng/kg per min dose elevated RBF and GFR by 13 and 14%, respectively, while concomitantly increasing APG by 38%. At 200 ng/kg per min, galanin elevated RBF and GFR by 32 and 33%, respectively, while elevating APG by 57%. Intrarenal infusion of glucose (12.5 mg/kg per min; n = 6), reproducing the percentage rise in glucose (62%) elicited by the highest dose of galanin, elevated RBF and GFR by 20 and 23%, respectively. These data indicate that the elevated plasma glucose level, stimulated by galanin infusion, may account for about 63 and 70% of the RBF and GFR responses, respectively, elicited by galanin infusion at the 200 ng dose. The factors mediating the remaining renal hyperemia and hyperfiltration await resolution.

Slow continuous renal replacement therapies: an update.

PubMed

Kes, P

2000-01-01

Continuous renal replacement therapies (CRRT) are now being used by nephrologists, intensivists, and anesthesiologists. The various CRRT modalities differ in the kind of vascular access, the application of diffusive or convective clearances (or a combination of both), and in the location where the replacement fluid enters the circuit. CRRTs have certainly made the management of critically ill patients with acute renal failure (ARF) combined with cardiovascular instability, severe fluid overload, hypercatabolism, cerebral edema, adult respiratory distress syndrome, lactic acidosis, sepsis or other inflammatory syndromes, crush syndrome, congestive heart failure, and cardiopulmonary bypass easier. Continuous therapies incorporate several advantages including improved hemodynamic stability, optimal fluid balance, gradual urea removal, elimination of septic mediators, and the possibility of unlimited parenteral nutrition. Major difficulties and unsolved problems of CRRT are the ongoing necessity of continuous anticoagulation, considerable loss of amino acids, vitamins, trace elements, potassium, phosphate, and some drugs, as well as immobilization of the patient. The advantages of CRRT should theoretically translate into improved outcomes of critically ill ARF patients, but the superiority of continuous modalities in terms of outcome is still controversial, despite encouraging results in some clinical trials. Currently used CRRT with sophisticated treatment devices has become more expensive than hemodialysis, but the cost cannot be used as an argument against the continuous treatment modalities.

Online Removal of Baseline Shift with a Polynomial Function for Hemodynamic Monitoring Using Near-Infrared Spectroscopy.

PubMed

Zhao, Ke; Ji, Yaoyao; Li, Yan; Li, Ting

2018-01-21

Near-infrared spectroscopy (NIRS) has become widely accepted as a valuable tool for noninvasively monitoring hemodynamics for clinical and diagnostic purposes. Baseline shift has attracted great attention in the field, but there has been little quantitative study on baseline removal. Here, we aimed to study the baseline characteristics of an in-house-built portable medical NIRS device over a long time (>3.5 h). We found that the measured baselines all formed perfect polynomial functions on phantom tests mimicking human bodies, which were identified by recent NIRS studies. More importantly, our study shows that the fourth-order polynomial function acted to distinguish performance with stable and low-computation-burden fitting calibration (R-square >0.99 for all probes) among second- to sixth-order polynomials, evaluated by the parameters R-square, sum of squares due to error, and residual. This study provides a straightforward, efficient, and quantitatively evaluated solution for online baseline removal for hemodynamic monitoring using NIRS devices.

[Study of sharing platform of web-based enhanced extracorporeal counterpulsation hemodynamic waveform data].

PubMed

Huang, Mingbo; Hu, Ding; Yu, Donglan; Zheng, Zhensheng; Wang, Kuijian

2011-12-01

Enhanced extracorporeal counterpulsation (EECP) information consists of both text and hemodynamic waveform data. At present EECP text information has been successfully managed through Web browser, while the management and sharing of hemodynamic waveform data through Internet has not been solved yet. In order to manage EECP information completely, based on the in-depth analysis of EECP hemodynamic waveform file of digital imaging and communications in medicine (DICOM) format and its disadvantages in Internet sharing, we proposed the use of the extensible markup language (XML), which is currently the Internet popular data exchange standard, as the storage specification for the sharing of EECP waveform data. Then we designed a web-based sharing system of EECP hemodynamic waveform data via ASP. NET 2.0 platform. Meanwhile, we specifically introduced the four main system function modules and their implement methods, including DICOM to XML conversion module, EECP waveform data management module, retrieval and display of EECP waveform module and the security mechanism of the system.

Renal function monitoring in heart failure - what is the optimal frequency? A narrative review.

PubMed

Al-Naher, Ahmed; Wright, David; Devonald, Mark Alexander John; Pirmohamed, Munir

2018-01-01

The second most common cause of hospitalization due to adverse drug reactions in the UK is renal dysfunction due to diuretics, particularly in patients with heart failure, where diuretic therapy is a mainstay of treatment regimens. Therefore, the optimal frequency for monitoring renal function in these patients is an important consideration for preventing renal failure and hospitalization. This review looks at the current evidence for optimal monitoring practices of renal function in patients with heart failure according to national and international guidelines on the management of heart failure (AHA/NICE/ESC/SIGN). Current guidance of renal function monitoring is in large part based on expert opinion, with a lack of clinical studies that have specifically evaluated the optimal frequency of renal function monitoring in patients with heart failure. Furthermore, there is variability between guidelines, and recommendations are typically nonspecific. Safer prescribing of diuretics in combination with other antiheart failure treatments requires better evidence for frequency of renal function monitoring. We suggest developing more personalized monitoring rather than from the current medication-based guidance. Such flexible clinical guidelines could be implemented using intelligent clinical decision support systems. Personalized renal function monitoring would be more effective in preventing renal decline, rather than reacting to it. © 2017 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.

Renal volume assessed by magnetic resonance imaging volumetry correlates with renal function in living kidney donors pre- and postdonation: a retrospective cohort study.

PubMed

Lange, Daniel; Helck, Andreas; Rominger, Axel; Crispin, Alexander; Meiser, Bruno; Werner, Jens; Fischereder, Michael; Stangl, Manfred; Habicht, Antje

2018-07-01

Renal function of potential living kidney donors is routinely assessed with scintigraphy. Kidney anatomy is evaluated by imaging techniques such as magnetic resonance imaging (MRI). We evaluated if a MRI-based renal volumetry is a good predictor of kidney function pre- and postdonation. We retrospectively analyzed the renal volume (RV) in a MRI of 100 living kidney donors. RV was correlated with the tubular excretion rate (TER) of MAG3-scintigraphy, a measured creatinine clearance (CrCl), and the estimated glomerular filtration rate (eGFR) by Cockcroft-Gault (CG), CKD-EPI, and modification of diet in renal disease (MDRD) formula pre- and postdonation during a follow-up of 3 years. RV correlated significantly with the TER (total: r = 0.6735, P < 0.0001). Correlation between RV and renal function was the highest for eGFR by CG (r = 0.5595, P < 0.0001), in comparison with CrCl, MDRD-GFR, and CKD-EPI-GFR predonation. RV significantly correlated with CG-GFR postdonation and predicted CG-GFR until 3 years after donation. MRI renal volumetry might be an alternative technique for the evaluation of split renal function and prediction of renal function postdonation in living kidney donors. © 2018 Steunstichting ESOT.

Clinical relevance of fetal hemodynamic monitoring: Perinatal implications.

PubMed

Pruetz, Jay D; Votava-Smith, Jodie; Miller, David A

2015-08-01

Comprehensive assessment of fetal wellbeing involves monitoring of fetal growth, placental function, central venous pressure, and cardiac function. Ultrasound evaluation of the fetus using 2D, color Doppler, and pulse-wave Doppler techniques form the foundation of antenatal diagnosis of structural anomalies, rhythm abnormalities and altered fetal circulation. Accurate and timely prenatal identification of the fetus at risk is critical for appropriate parental counseling, antenatal diagnostic testing, consideration for fetal intervention, perinatal planning, and coordination of postnatal care delivery. Fetal hemodynamic monitoring and serial assessment are vital to ensuring fetal wellbeing, particularly in the setting of complex congenital anomalies. A complete hemodynamic evaluation of the fetus gives important information on the likelihood of a smooth postnatal transition and contributes to ensuring the best possible outcome for the neonate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Patient-Specific Modeling of Interventricular Hemodynamics in Single Ventricle Physiology

NASA Astrophysics Data System (ADS)

Vedula, Vijay; Feinstein, Jeffrey; Marsden, Alison

2016-11-01

Single ventricle (SV) congenital heart defects, in which babies are born with only functional ventricle, lead to significant morbidity and mortality with over 30% of patients developing heart failure prior to adulthood. Newborns with SV physiology typically undergo three palliative surgeries, in which the SV becomes the systemic pumping chamber. Depending on which ventricle performs the systemic function, patients are classified as having either a single left ventricle (SLV) or a single right ventricle (SRV), with SRV patients at higher risk of failure. As the native right ventricles are not designed to meet systemic demands, they undergo remodeling leading to abnormal hemodynamics. The hemodynamic characteristics of SLVs compared with SRVs is not well established. We present a validated computational framework for performing patient-specific modeling of ventricular flows, and apply it across 6 SV patients (3SLV + 3SRV), comparing hemodynamic conditions between the two subgroups. Simulations are performed with a stabilized finite element method coupled with an immersed boundary method for modeling heart valves. We discuss identification of hemodynamic biomarkers of ventricular remodeling for early risk assessment of failure. This research is supported in part by the Stanford Child Health Research Institute and the Stanford NIH-NCATS-CTSA through Grant UL1 TR001085 and due to U.S. National Institute of Health through NIH NHLBI R01 Grants 5R01HL129727-02 and 5R01HL121754-03.

Renal and femoral venous blood flows are regulated by different mechanisms dependent on α-adrenergic receptor subtypes and nitric oxide in anesthetized rats.

PubMed

Fioretti, Alexandre C; Ogihara, Cristiana A; Cafarchio, Eduardo M; Venancio, Daniel P; de Almeida, Roberto Lopes; Antonio, Bruno B; Sato, Monica A

2017-12-01

Venous and arterial walls are responsive to sympathetic system and circulating substances, nevertheless, very few is known about the venous blood flow regulation simultaneously to arterial vascular beds. In this study, we compared the venous and arterial blood flow regulation in visceral and muscular beds upon injection of different doses of vasoactive drugs which act in arterial vascular beds. Anesthetized adult male Wistar rats underwent to right femoral artery and vein cannulation for hemodynamic recordings and infusion of drugs. Doppler flow probes were placed around the left renal artery and vein, and left femoral artery and vein to evaluate the changes in flood flow. Phenylephrine (PHE) injection (α 1 -adrenergic receptor agonist) elicited vasoconstriction in all arteries and veins. Intravenous prazosin (PZS) (1mg/kg, α 1 -adrenergic receptor blocker) caused renal artery vasodilation, but not in the other beds. Vasoconstrictor effect of PHE was abolished by PZS in all vascular beds, except in femoral vein. Phentolamine (PTL) injection (1mg/kg, α 1 /α 2 -adrenergic receptor blocker) produced renal artery vasodilation with no change in other beds. After PTL, the vasoconstriction evoked by PHE was abolished in all vascular beds. Sodium Nitroprusside (SNP), a nitric oxide donor, elicited vasodilation in all beds, and after PTL but not post PZS injection, SNP enhanced the vasodilatory effect in femoral vein. Our findings suggest that the vasoconstriction in renal and femoral veins is mediated by different subtypes of α-adrenoceptors. The nitric oxide-dependent vasodilation in femoral vein enhances when α 2 -adrenoceptors are not under stimulation, but not in the other vascular beds investigated. Copyright © 2017 Elsevier Inc. All rights reserved.

Stress and sodium intake in neural control of renal function in hypertension.

PubMed

DiBona, G F

1991-04-01

The interaction between genetic and environmental factors is important in the pathophysiology of hypertension. By examining the effects of two environmental factors--acute psychoemotional stress and dietary sodium intake--in rats with genetic hypertension, an important influence on central neural mechanisms governing the renal sympathetic neural control of renal function has been demonstrated. Additional studies of the central opioid systems have demonstrated an important role of opioid peptides in modulating the renal functional responses to acute psychoemotional stress. The observed renal functional alterations--antidiuresis, antinatriuresis, and renal vasoconstriction--are known to be capable of contributing to the initiation, development, and maintenance of the hypertensive process.

Extra-cardiac manifestations of adult congenital heart disease.

PubMed

Gaeta, Stephen A; Ward, Cary; Krasuski, Richard A

2016-10-01

Advancement in correction or palliation of congenital cardiac lesions has greatly improved the lifespan of congenital heart disease patients, resulting in a rapidly growing adult congenital heart disease (ACHD) population. As this group has increased in number and age, emerging science has highlighted the systemic nature of ACHD. Providers caring for these patients are tasked with long-term management of multiple neurologic, pulmonary, hepatic, renal, and endocrine manifestations that arise as syndromic associations with congenital heart defects or as sequelae of primary structural or hemodynamic abnormalities. In this review, we outline the current understanding and recent research into these extra-cardiac manifestations. Copyright © 2016 Elsevier Inc. All rights reserved.

Severe hypothyroidism presenting as myxedema coma in the postoperative period in a patient taking sunitinib: case report and review of literature.

PubMed

Lele, Abhijit V; Clutter, Sarah; Price, Eleana; De Ruyter, Martin L

2013-02-01

The case of a 62-year-old Caucasian woman who underwent urgent hip hemiarthroplasty for repair of a pathological fracture is reported. The patient's medical history was significant for renal cell carcinoma, cerebellar metastases, and sunitinib-induced hypothyroidism. Her intraoperative course was complicated by profound hypothermia, bradycardia, augmentation of neuromuscular blockade, delayed emergence, failure of postoperative extubation, and need for mechanical ventilation. The intensive care course was significant for hypothermia requiring forced-air warming, treatment with intravenous thyroxine (T4), and hemodynamic supportive care. Copyright © 2013 Elsevier Inc. All rights reserved.

Hemodynamic and Electrophysiological Relationship Involved in Human Face Processing: Evidence from a Combined fMRI-ERP Study

ERIC Educational Resources Information Center

Iidaka, Tetsuya; Matsumoto, Atsushi; Haneda, Kaoruko; Okada, Tomohisa; Sadato, Norihiro

2006-01-01

Functional magnetic resonance imaging (fMRI) and event-related potential (ERP) experiments were conducted in the same group of subjects and with an identical task paradigm to investigate a possible relationship between hemodynamic and electrophysiological responses within the brain. The subjects were instructed to judge whether visually presented…

[Liver transplantation preserving the vena cava and a temporary portocaval shunt].

PubMed

Hesse, U J; Berrevoet, F; Troisi, R; Mortier, E; Decruyenaere, J; Pattyn, P; de Hemptinne, B

1999-02-01

The experience with laterolateral cavocavostomy for hepatovenous reconstruction in liver transplantation is reviewed with and without the use of a temporary portocaval shunt. A total of 65 liver transplantations were analyzed. In 49 transplantations a laterolateral cavocaval anastomosis was performed (group I). In group II (n = 16) the same technique was used after a temporary portal caval shunt was constructed. Mean arterial pressure (mmHg): group I 128 +/- 34; group II 109 +/- 32. Cardiac output (l/min) decrease during the anhepatic phase was 2.3 +/- 1.9 and 1.2 +/- 1.5, respectively (P < 0.05). The peroperative blood loss measured as the number of packed cells transfused was 16.4 +/- 15.8 versus 1.2 +/- 2.3 (P < 0.04) and fresh frozen plasma 19.0 +/- 14.7 versus 3.7 +/- 4.0 (P < 0.02). Course on ICU (days), liver function tests, renal function and the need for reoperation because of bleeding were not statistically significantly different between the groups. One-year patient survival was 82.7 and 85.7%, respectively. In conclusion, we found that despite preservation of the caval flow during hepatectomy, the additional use of a temporary portocaval shunt was advantageous with regard to peroperative hemorrhage and hemodynamic stability and can potentially facilitate implantation of the liver graft.

Assessment of right ventricular longitudinal strain by 2D speckle tracking imaging compared with RV function and hemodynamics in pulmonary hypertension.

PubMed

Li, Yidan; Wang, Yidan; Meng, Xiangli; Zhu, Weiwei; Lu, Xiuzhang

2017-11-01

The right ventricular longitudinal strain (RVLS) of pulmonary hypertension (PH) patients and its relationship with RV function parameters measured by echocardiography and hemodynamic parameters measured by right heart catheterization was investigated. According to the WHO functional class (FC), 66 PH patients were divided into FC I/II (group 1) and III/IV (group 2). RV function parameters were measured by echocardiographic examinations. Hemodynamic parameters were obtained by right heart catheterization. Patients in group 2 had higher systolic pulmonary artery pressure (sPAP; P < 0.05) than patients in group (1) significant between-group differences were observed in global RVLS (RVLS global ), free wall RVLS (RVLS FW ; P < 0.01), and RV conventional function parameters (all P < 0.05). Moreover, mPAP and PVR increased remarkably and CI decreased significantly in group (2) RVLS global had a positive correlation with 6-min walking distance (6MWD; r = 0.492, P < 0.001) and N-terminal pro-brain natriuretic peptide (NT-proBNP; r = 0.632, P < 0.001), while RVLS FW had a positive correlation with 6MWD (r = 0.483, P < 0.001) and NT-proBNP (r = 0.627, P < 0.001). Hemodynamics analysis revealed that RVLS global had a positive correlation with mPAP (r = 0.594, P < 0.001), PVR (r = 0.573, P < 0.001) and CI (r = 0.366, P = 0.003), while RVLS FW had a positive correlation with mPAP (r = 0.597, P < 0.001), PVR (r = 0.577, P < 0.001) and CI (r = 0.369, P = 0.002). According to receiver operating characteristic curves, the optimal cut-off values of RVLS global (-15.0%) and RVLS FW (-15.3%) for prognosis detection with good sensitivity and specificity. Evidence has shown that RVLS measurement can provide the much-needed and reliable information on RV function and hemodynamics. Therefore, this qualifies as a patient-friendly approach for the clinical management of PH patients.

The Effect of Patient and Surgical Characteristics on Renal Function After Partial Nephrectomy.

PubMed

Winer, Andrew G; Zabor, Emily C; Vacchio, Michael J; Hakimi, A Ari; Russo, Paul; Coleman, Jonathan A; Jaimes, Edgar A

2018-06-01

The purpose of the study was to identify patient and disease characteristics that have an adverse effect on renal function after partial nephrectomy. We conducted a retrospective review of 387 patients who underwent partial nephrectomy for renal tumors between 2006 and 2014. A line plot with a locally weighted scatterplot smoothing was generated to visually assess renal function over time. Univariable and multivariable longitudinal regression analyses incorporated a random intercept and slope to evaluate the association between patient and disease characteristics with renal function after surgery. Median age was 60 years and most patients were male (255 patients [65.9%]) and white (343 patients [88.6%]). In univariable analysis, advanced age at surgery, larger tumor size, male sex, longer ischemia time, history of smoking, and hypertension were significantly associated with lower preoperative estimated glomerular filtration rate (eGFR). In multivariable analysis, independent predictors of reduced renal function after surgery included advanced age, lower preoperative eGFR, and longer ischemia time. Length of time from surgery was strongly associated with improvement in renal function among all patients. Independent predictors of postoperative decline in renal function include advanced age, lower preoperative eGFR, and longer ischemia time. A substantial number of subjects had recovery in renal function over time after surgery, which continued past the 12-month mark. These findings suggest that patients who undergo partial nephrectomy can experience long-term improvement in renal function. This improvement is most pronounced among younger patients with higher preoperative eGFR. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of exercise training on pulmonary hemodynamics, functional capacity and inflammation in pulmonary hypertension

PubMed Central

Richter, Manuel J.; Grimminger, Jan; Krüger, Britta; Ghofrani, Hossein A.; Mooren, Frank C.; Gall, Henning; Pilat, Christian; Krüger, Karsten

2017-01-01

Pulmonary hypertension (PH) is characterized by severe exercise limitation mainly attributed to the impairment of right ventricular function resulting from a concomitant elevation of pulmonary vascular resistance and pressure. The unquestioned cornerstone in the management of patients with pulmonary arterial hypertension (PAH) is specific vasoactive medical therapy to improve pulmonary hemodynamics and strengthen right ventricular function. Nevertheless, evidence for a beneficial effect of exercise training (ET) on pulmonary hemodynamics and functional capacity in patients with PH has been growing during the past decade. Beneficial effects of ET on regulating factors, inflammation, and metabolism have also been described. Small case-control studies and randomized clinical trials in larger populations of patients with PH demonstrated substantial improvements in functional capacity after ET. These findings were accompanied by several studies that suggested an effect of ET on inflammation, although a direct link between this effect and the therapeutic benefit of ET in PH has not yet been demonstrated. On this background, the aim of the present review is to describe current concepts regarding the effects of exercise on the pulmonary circulation and pathophysiological limitations, as well as the clinical and mechanistic effects of exercise in patients with PH. PMID:28680563

Nonlinear extension of a hemodynamic linear model for coherent hemodynamics spectroscopy.

PubMed

Sassaroli, Angelo; Kainerstorfer, Jana M; Fantini, Sergio

2016-01-21

In this work, we are proposing an extension of a recent hemodynamic model (Fantini, 2014a), which was developed within the framework of a novel approach to the study of tissue hemodynamics, named coherent hemodynamics spectroscopy (CHS). The previous hemodynamic model, from a signal processing viewpoint, treats the tissue microvasculature as a linear time-invariant system, and considers changes of blood volume, capillary blood flow velocity and the rate of oxygen diffusion as inputs, and the changes of oxy-, deoxy-, and total hemoglobin concentrations (measured in near infrared spectroscopy) as outputs. The model has been used also as a forward solver in an inversion procedure to retrieve quantitative parameters that assess physiological and biological processes such as microcirculation, cerebral autoregulation, tissue metabolic rate of oxygen, and oxygen extraction fraction. Within the assumption of "small" capillary blood flow velocity oscillations the model showed that the capillary and venous compartments "respond" to this input as low pass filters, characterized by two distinct impulse response functions. In this work, we do not make the assumption of "small" perturbations of capillary blood flow velocity by solving without approximations the partial differential equation that governs the spatio-temporal behavior of hemoglobin saturation in capillary and venous blood. Preliminary comparison between the linear time-invariant model and the extended model (here identified as nonlinear model) are shown for the relevant parameters measured in CHS as a function of the oscillation frequency (CHS spectra). We have found that for capillary blood flow velocity oscillations with amplitudes up to 10% of the baseline value (which reflect typical scenarios in CHS), the discrepancies between CHS spectra obtained with the linear and nonlinear models are negligible. For larger oscillations (~50%) the linear and nonlinear models yield CHS spectra with differences within typical experimental errors, but further investigation is needed to assess the effect of these differences. Flow oscillations larger than 10-20% are not typically induced in CHS; therefore, the results presented in this work indicate that a linear hemodynamic model, combined with a method to elicit controlled hemodynamic oscillations (as done for CHS), is appropriate for the quantitative assessment of cerebral microcirculation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Shed a light in fatigue detection with near-infrared spectroscopy during long-lasting driving

NASA Astrophysics Data System (ADS)

Gao, Yuan; Pan, Boan; Li, Kai; Li, Ting

2016-03-01

Fatigue driving is one of the leading roles to induce traffic accident and injury, which urgently desires a novel technique to monitor the fatigue level at driving. Functional near infrared spectroscopy (fNIRS) is capable of noninvasive monitoring brain-activities-related hemodynamic responses. Here, we developed a fINRS imager and setup a classic psychological experiment to trigger visual divided attention which varied responding to driving fatigue, and attempted to record the drive-fatigue-level correlated hemodynamic response in the prefrontal cortex. 7 volunteers were recruited to take 7 hours driving and the experimental test was repeated every 1 hour and 8 times in total. The hemodynamic response were extracted and graphed with pseudo image. The analysis on the relationship between the fNIRS-measured hemodynamic response and fatigue level finally displayed that the oxyhemoglobin concentration in one channel of left prefrontal lobe increased with driving duration in significant correlation. And the spatial pattern of hemodynamic response in the prefrontal lobe varied with driving duration as well. The findings indicated the potential of fNIRSmeasured hemodynamic index in some sensitive spot of prefrontal lobe as a driving fatigue indicator and the promising use of fNIRS in traffic safety field.

Hemodynamic and metabolic effects of estrogen plus progestin therapy in hypertensive postmenopausal women treated with an ACE-inhibitor or a diuretic.

PubMed

Posadzy-Malaczynska, Anna; Rajpold, Katarzyna; Woznicka-Leskiewicz, Lucyna; Marcinkowska, Justyna

2015-01-01

The aim of the study was to assess the hemodynamic and metabolic actions of estrogen plus progestin therapy (EPT) in hypertensive, postmenopausal women treated with perindopril (ACEI) or hydrochlorothiazide (HCTZ). A group of normotensive postmenopausal women was also studied. 100 hypertensive and 40 normotensive postmenopausal women were recruited for the study. The hypertensive females were randomly assigned to receive ACEI or HCTZ for 12 months. The patients of the ACEI group and the patients of the HCTZ group, as well as normotensives, were further subdivided into two subgroups each. One subgroup received estrogen plus progestin therapy (EPT+), the other subgroup received no hormone replacement (EPT-). Combined hormone replacement with transdermal patches releasing 17β-estradiol and norethisterone was used. Office and 24-hour ambulatory blood pressure was measured at baseline and during follow-up. Renal plasma flow (RPF) was measured using the clearance of [125I]-iodohippuran. Pulse wave velocity (PWV) was determined with an automatic device. In normotensive postmenopausal women, transdermal estrogen plus progestin therapy increases RPF and insulin sensitivity, decreases PWV, decreases total and LDL cholesterol, and decreases uric acid serum levels. Perindopril (4 mg/day) and hydrochlorothiazide (25 mg/day) were equally effective in reducing blood pressure in postmenopausal, hypertensive subjects. In these females, perindopril increased RPF and decreased PWV and plasma insulin levels. These effects of the ACEI were not altered by estrogen plus progestin therapy. Hydrochlorothiazide decreased RPF and increased plasma insulin and uric acid concentrations in hypertensive subjects whom were not receiving estrogen plus progestin therapy. The unfavorable metabolic and hemodynamic actions of the diuretic were counteracted by estrogen plus progestin therapy. Concomitant estrogen plus progestin therapy may be a method to avoid unfavorable hemodynamic and metabolic effects of thiazide diuretics in hypertensive, postmenopausal women.

Nervous kidney. Interaction between renal sympathetic nerves and the renin-angiotensin system in the control of renal function.

PubMed

DiBona, G F

2000-12-01

Increases in renal sympathetic nerve activity regulate the functions of the nephron, the vasculature, and the renin-containing juxtaglomerular granular cells. Because increased activity of the renin-angiotensin system can also influence nephron and vascular function, it is important to understand the interactions between the renal sympathetic nerves and the renin-angiotensin system in the control of renal function. These interactions can be intrarenal, for example, the direct (by specific innervation) and indirect (by angiotensin II) contributions of increased renal sympathetic nerve activity to the regulation of renal function. The effects of increased renal sympathetic nerve activity on renal function are attenuated when the activity of the renin-angiotensin system is suppressed or antagonized with ACE inhibitors or angiotensin II-type AT(1)-receptor antagonists. The effects of intrarenal administration of angiotensin II are attenuated after renal denervation. These interactions can also be extrarenal, for example, in the central nervous system, wherein renal sympathetic nerve activity and its arterial baroreflex control are modulated by changes in activity of the renin-angiotensin system. In addition to the circumventricular organs, whose permeable blood-brain barrier permits interactions with circulating angiotensin II, there are interactions at sites behind the blood-brain barrier that depend on the influence of local angiotensin II. The responses to central administration of angiotensin II-type AT(1)-receptor antagonists into the ventricular system or microinjected into the rostral ventrolateral medulla are modulated by changes in activity of the renin-angiotensin system produced by physiological changes in dietary sodium intake. Similar modulation is observed in pathophysiological models wherein activity of both the renin-angiotensin and sympathetic nervous systems is increased (eg, congestive heart failure). Thus, both renal and extrarenal sites of interaction between the renin-angiotensin system and renal sympathetic nerve activity are involved in influencing the neural control of renal function.

Acetylator Status Impacts Amifampridine Phosphate (Firdapse™) Pharmacokinetics and Exposure to a Greater Extent Than Renal Function.

PubMed

Haroldsen, Peter E; Sisic, Zlatko; Datt, Joe; Musson, Donald G; Ingenito, Gary

2017-07-01

The purpose of this study is to evaluate safety, tolerability, and pharmacokinetic (PK) properties of amifampridine phosphate (Firdapse™) and its major inactive 3-N-acetyl metabolite in renally impaired and healthy individuals with slow acetylator (SA) and rapid acetylator (RA) phenotypes. This was a Phase I, multicenter, open-label study of the PK properties and safety profile of amifampridine phosphate in individuals with normal, mild, moderate, or severely impaired renal function. Amifampridine phosphate was given as a single 10 mg (base equivalent) dose, and the plasma and urine PK properties of amifampridine and its 3-N-acetyl metabolite were determined. The safety profile was evaluated by monitoring adverse events (AEs), clinical laboratory tests, and physical examinations. Amifampridine clearance was predominantly metabolic through N-acetylation, regardless of renal function in both acetylator phenotypes. In individuals with normal renal function, mean renal clearance represented approximately 3% and 18% of the total clearance of amifampridine in RA and SA, respectively. Large differences in amifampridine exposure were observed between acetylation phenotypes across renal function levels. Mean amifampridine exposure values of AUC 0-∞ and C max were up to 8.8-fold higher in the SA group compared with the RA group across renal function levels. By comparison, mean AUC 0-∞ was less affected by renal function within an acetylator group, only 2- to 3-fold higher in individuals with severe renal impairment (RI) compared with those with normal renal function. Exposure to amifampridine in the SA group with normal renal function was higher (AUC 0-∞, approximately 1.8-fold; C max, approximately 4.1-fold) than the RA group with severe RI. Exposure to the inactive 3-N-acetyl metabolite was higher than amifampridine in both acetylator groups, independent of renal function level. The metabolite is cleared by renal excretion, and exposure was clearly dependent on renal function with 4.0- to 6.8-fold increases in AUC 0-∞ from normal to severe RI. No new tolerability findings were observed. A single dose of 10 mg of amifampridine phosphate was well tolerated, independent of renal function and acetylator status. The results indicate that the PK profile of amifampridine is affected by metabolic acetylator phenotype to a greater extent than by renal function level, supporting Firdapse™ administration in individuals with RI in line with current labeling recommendations. Amifampridine should be dosed to effect per the individual patient need, altering administration frequency and dose in normal through severe RI. The therapeutic dose of amifampridine phosphate should be tailored to the individual patient needs by gradual dose titration up to the present maximum recommended dose (60-80 mg/day) or until dose-limiting AEs intervene to avoid overdosing and underdosing. EudraCT identifier: 2013-005349-35. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Relationship between histopathological changes in post partum renal biopsies and renal function tests of African women with early onset pre-eclampsia.

PubMed

Khedun, S M; Naicker, T; Moodley, J

2000-05-01

To improve the diagnostic accuracy of concurrent renal disease in hypertension of pregnancy, biopsy evaluation is essential. In addition, establishing underlying renal disease is important for prognosis on future pregnancies. We therefore designed a study to determine the diagnostic yield of postpartum renal biopsy and the nature and frequency of complications associated with this procedure. Also, to determine relationships, if any, between renal function tests and ultrastructural and histopathological findings. Fifty renal biopsies were performed in the immediate postpartum period in black African women with early onset pre-eclampsia. Each biopsy specimen was placed in a separate container and coded so that sampling was unknown to the electron microscopist. Each biopsy specimen was divided into three parts, and processed and stained for light, fluorescent and transmission electron microscopy using conventional techniques. Renal tissue biopsies were adequate for diagnostic purposes in all cases. There were no complications in any of the 50 patients studied. Ultrastructural examination confirmed the light microscopy findings. In addition the ultrastructural findings showed intramembranous deposits, foot process fusion and mesangial deposits. In 16 patients with normal renal function tests; the biopsies evaluation from these patients showed ultrastructural changes. In the remaining 34 patients with abnormal renal function tests of varying severity; biopsy evaluation from these patients showed both ultrastructural and histopathological changes. Renal biopsy procedure is safe, and ultrastructural and histological findings obtained from postpartum renal biopsies are more informative than the routine renal function tests.

Renal function decline predicted by left atrial expansion index in non-diabetic cohort with preserved systolic heart function.

PubMed

Hsiao, Shih-Hung; Chiou, Kuan-Rau

2017-05-01

Since natriuretic peptide and troponin are associated with renal prognosis and left atrial (LA) parameters are indicators of subclinical cardiovascular abnormalities, this study investigated whether LA expansion index can predict renal decline. This study analysed 733 (69% male) non-diabetic patients with sinus rhythm, preserved systolic function, and estimated glomerular filtration rate (eGFR) higher than 60 mL/min/1.73 m2. In all patients, echocardiograms were performed and LA expansion index was calculated. Renal function was evaluated annually. The endpoint was a downhill trend in renal function with a final eGFR of <60 mL/min/1.73 m2. Rapid renal decline was defined as an annual decline in eGFR >3 mL/min/1.73 m2. The median follow-up time was 5.2 years, and 57 patients (7.8%) had renal function declines (19 had rapid renal declines, and 38 had incidental renal dysfunction). Events were associated with left ventricular mass index, LA expansion index, and heart failure during the follow-up period. The hazard ratio was 1.426 (95% confidence interval, 1.276-1.671; P < 0.0001) per 10% decrease in LA expansion index and was independently associated with an increased event rate. Compared with the highest quartile for the LA expansion index, the lowest quartile had a 9.7-fold risk of renal function decline in the unadjusted model and a 6.9-fold risk after adjusting for left ventricular mass index and heart failure during the follow-up period. Left atrial expansion index is a useful early indicator of renal function decline and may enable the possibility of early intervention to prevent renal function from worsening. NCT01171040. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Longitudinal changes in kidney parenchymal volume associated with renal artery stenting.

PubMed

Modrall, J Gregory; Timaran, Carlos H; Rosero, Eric B; Chung, Jayer; Plummer, Mitchell; Valentine, R James; Trimmer, Clayton

2012-03-01

This study assessed the longitudinal changes in renal volume after renal artery stenting (RAS) to determine if renal mass is preserved by stenting. The study cohort consisted of 38 patients with longitudinal imaging available for renal volume quantification before and after RAS. Renal volume was estimated as (kidney length) × (width) × (depth/2) based on preoperative renal imaging. For each patient, the clinical response of blood pressure (BP) and renal function to RAS was categorized according to modified American Heart Association guidelines. Changes in renal volume were assessed using paired nonparametric analyses. The cohort was a median age of 69 years (interquartile range [IQR], 60-74 years). A favorable BP response was observed in 11 of 38 patients (28.9%). At a median interval between imaging studies of 21 months (IQR, 13-32 months), ipsilateral renal volume was significantly increased from baseline (146.8 vs 133.8 cm(3);P = .02). This represents a 6.9% relative increase in ipsilateral kidney volume from baseline. A significant negative correlation between preoperative renal volume and the relative change in renal volume postoperatively (r = -0.42; P = .0055) suggests that smaller kidneys experienced the greatest gains in renal volume after stenting. It is noteworthy that the 25 patients with no change in BP or renal function-clinical failures using traditional definitions-experienced a 12% relative increase in ipsilateral renal volume after RAS. Multivariate analysis determined that stable or improved renal volume after stenting was an independent predictor of stable or improved long-term renal function (odds ratio, 0.008; 95% confidence interval, 0.000-0.206; P = .004). These data lend credence to the belief that RAS preserves renal mass in some patients. This benefit of RAS even extends to those patients who would be considered treatment failures by traditional definitions. Patients with stable or increased renal volume after RAS had more stable renal function during long-term follow-up, whereas patients with renal volume loss after stenting were prone to deterioration of renal function. Published by Mosby, Inc.

The renin-angiotensin system in thyroid disorders and its role in cardiovascular and renal manifestations.

PubMed

Vargas, Félix; Rodríguez-Gómez, Isabel; Vargas-Tendero, Pablo; Jimenez, Eugenio; Montiel, Mercedes

2012-04-01

Thyroid disorders are among the most common endocrine diseases and affect virtually all physiological systems, with an especially marked impact on cardiovascular and renal systems. This review summarizes the effects of thyroid hormones on the renin-angiotensin system (RAS) and the participation of the RAS in the cardiovascular and renal manifestations of thyroid disorders. Thyroid hormones are important regulators of cardiac and renal mass, vascular function, renal sodium handling, and consequently blood pressure (BP). The RAS acts globally to control cardiovascular and renal functions, while RAS components act systemically and locally in individual organs. Various authors have implicated the systemic and local RAS in the mediation of functional and structural changes in cardiovascular and renal tissues due to abnormal thyroid hormone levels. This review analyzes the influence of thyroid hormones on RAS components and discusses the role of the RAS in BP, cardiac mass, vascular function, and renal abnormalities in thyroid disorders.

Changes in Renal Function and Blood Pressure in Patients with Stone Disease

NASA Astrophysics Data System (ADS)

Worcester, Elaine M.

2007-04-01

Stone disease is a rare cause of renal failure, but a history of kidney stones is associated with an increased risk for chronic kidney disease, particularly in overweight patients. Loss of renal function seems especially notable for patients with stones associated with cystinuria, hyperoxaluria, and renal tubular acidosis, in whom the renal pathology shows deposits of mineral obstructing inner medullary collecting ducts, often diffusely. However, even idiopathic calcium oxalate stone formers have a mild but significant decrease in renal function, compared to age, sex and weight-matched normals, and appear to lose renal function with age at a slightly faster rate than non-stone formers. There is also an increased incidence of hypertension among stone formers, although women are more likely to be affected than men.

Effect of renal impairment on the pharmacokinetics, pharmacodynamics, and safety of empagliflozin, a sodium glucose cotransporter 2 inhibitor, in Japanese patients with type 2 diabetes mellitus.

PubMed

Sarashina, Akiko; Ueki, Kohjiro; Sasaki, Tomohiro; Tanaka, Yuko; Koiwai, Kazuki; Sakamoto, Wataru; Woerle, Hans J; Salsali, Afshin; Broedl, Uli C; Macha, Sreeraj

2014-11-01

The purpose of this study was to assess the effect of renal impairment on the pharmacokinetic, pharmacodynamic, and safety profiles of empagliflozin, a sodium glucose cotransporter 2 (SGLT2) inhibitor, in Japanese patients with type 2 diabetes mellitus (T2DM). In an open-label, parallel-group study, 32 Japanese patients with T2DM and different degrees of renal function (n = 8 per renal function category: normal renal function, estimated glomerular filtration rate [eGFR; Japanese equation] ≥90 mL/min/1.73 m(2); mild renal impairment, eGFR of 60-<90 mL/min/1.73 m(2); moderate renal impairment, eGFR of 30-<60 mL/min/1.73 m(2); and severe renal impairment, eGFR of 15-<30 mL/min/1.73 m(2)) received a single 25 mg dose of empagliflozin. Empagliflozin exposure increased with increasing renal impairment. Maximum empagliflozin plasma concentrations were similar among all renal function groups. Adjusted geometric mean ratios for extent of exposure (AUC0-∞) to empagliflozin versus normal renal function were 128.8% (95% CI, 106.0-156.6%), 143.8% (95% CI, 118.3-174.8%), and 152.3% (95% CI, 125.3-185.2%) for patients with mild, moderate, and severe renal impairment, respectively. Decreases in renal clearance of empagliflozin correlated with eGFR. Urinary glucose excretion decreased with increasing renal impairment and correlated with eGFR (adjusted mean [SE] change from baseline: 75.0 [4.84] g, 62.6 [5.75] g, 57.9 [4.86] g, and 23.7 [5.24] g for patients with normal renal function and mild, moderate, and severe renal impairment, respectively). Only 2 patients (6%) had adverse events; both were mild. Pharmacokinetic data suggest that no dose adjustment of empagliflozin is necessary in Japanese patients with T2DM and renal impairment because increases in exposure were <2-fold. Urinary glucose excretion decreased with increasing renal impairment. ClinicalTrials.gov identifier: NCT01581658. Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.

The rebirth of interest in renal tubular function.

PubMed

Lowenstein, Jerome; Grantham, Jared J

2016-06-01

The measurement of glomerular filtration rate by the clearance of inulin or creatinine has evolved over the past 50 years into an estimated value based solely on plasma creatinine concentration. We have examined some of the misconceptions and misunderstandings of the classification of renal disease and its course, which have followed this evolution. Furthermore, renal plasma flow and tubular function, which in the past were estimated by the clearance of the exogenous aryl amine, para-aminohippurate, are no longer measured. Over the past decade, studies in experimental animals with reduced nephron mass and in patients with reduced renal function have identified small gut-derived, protein-bound uremic retention solutes ("uremic toxins") that are poorly filtered but are secreted into the lumen by organic anion transporters (OATs) in the proximal renal tubule. These are not effectively removed by conventional hemodialysis or peritoneal dialysis. Residual renal function, urine produced in patients with advanced renal failure or undergoing dialysis treatment, may represent, at least in part, secretion of fluid and uremic toxins, such as indoxyl sulfate, mediated by proximal tubule OATs and might serve as a useful survival function. In light of this new evidence of the physiological role of proximal tubule OATs, we suggest that measurement of renal tubular function and renal plasma flow may be of considerable value in understanding and managing chronic kidney disease. Data obtained in normal subjects indicate that renal plasma flow and renal tubular function might be measured by the clearance of the endogenous aryl amine, hippurate. Copyright © 2016 the American Physiological Society.

The Value of Quality Improvement Process in the Detection and Correction of Common Errors in Echocardiographic Hemodynamic Parameters in a Busy Echocardiography Laboratory

PubMed Central

Fanari, Zaher; Choudhry, Usman I; Reddy, Vivek K; Eze-Nliam, Chete; Hammami, Sumaya; Kolm, Paul; Weintraub, William S.; Marshall, Erik S

2015-01-01

Background Accurate assessment of cardiac structures, ventricular function, and hemodynamics are essential for any echocardiographic laboratory. Quality Improvement (QI) processes described by the American Society of Echocardiography (ASE) and the Intersocietal Commission (IAC) should be instrumental in reaching this goal. Methods All patients undergoing transthoracic echocardiogram (TTE) followed by cardiac catheterization within 24 hours at Christiana Care Health System in 2011 and 2012 were identified, with 126 and 133 cases respectively. Hemodynamic parameters of diastolic function, Pulmonary Artery Systolic Pressure (PASP) on TTE correlated poorly with catheterization in 2011. An educational process was developed and implemented at quarterly QI meetings based on ASE and IAC recommendations to target frequently encountered errors and provide methods for improved performance. The hemodynamic parameters were then re-examined in 2012 post-intervention. Results Following the QI process, there was significant improvement in the correlation between invasive and echocardiographic hemodynamic measurements in both systolic and diastolic function, and PASP. This reflected in significant better correlations between echo and cath LVEF [R = 0.88, ICC=0.87 vs. R = 0.85, ICC=0.85; p <0.001], Average E/E’ and of left Ventricle End Diastolic Pressure (LVEDP) [R = 0.62vs. R = 0.09, p = 0.006] and a better correlation for PASP [R= 0.77, ICC=0.77 vs. R = 0.30, ICC=0.31; p = 0.05] in 2012 compared to 2011. Conclusion The QI process, as recommended by ASE and IAC, can allow for identification as well as rectification of quality issues in a large regional academic medical center hospital. PMID:26033297

The Value of Quality Improvement Process in the Detection and Correction of Common Errors in Echocardiographic Hemodynamic Parameters in a Busy Echocardiography Laboratory.

PubMed

Fanari, Zaher; Choudhry, Usman I; Reddy, Vivek K; Eze-Nliam, Chete; Hammami, Sumaya; Kolm, Paul; Weintraub, William S; Marshall, Erik S

2015-12-01

Accurate assessment of cardiac structures, ventricular function, and hemodynamics is essential for any echocardiographic laboratory. Quality improvement (QI) processes described by the American Society of Echocardiography (ASE) and the Intersocietal Commission (IAC) should be instrumental in reaching this goal. All patients undergoing transthoracic echocardiogram (TTE) followed by cardiac catheterization within 24 hours at Christiana Care Health System in 2011 and 2012 were identified, with 126 and 133 cases, respectively. Hemodynamic parameters of diastolic function and pulmonary artery systolic pressure (PASP) on TTE correlated poorly with catheterization in 2011. An educational process was developed and implemented at quarterly QI meetings based on ASE and IAC recommendations to target frequently encountered errors and provide methods for improved performance. The hemodynamic parameters were then reexamined in 2012 postintervention. Following the QI process, there was significant improvement in the correlation between invasive and echocardiographic hemodynamic measurements in both systolic and diastolic function, and PASP. This reflected in significant better correlations between echo and cath LVEF [R = 0.88, ICC = 0.87 vs. R = 0.85, ICC = 0.85; P < 0.001], average E/E' and of left ventricle end-diastolic pressure (LVEDP) [R = 0.62 vs. R = 0.09, P = 0.006] and a better correlation for PASP [R = 0.77, ICC = 0.77 vs. R = 0.30, ICC = 0.31; P = 0.05] in 2012 compared to 2011. The QI process, as recommended by ASE and IAC, can allow for identification as well as rectification of quality issues in a large regional academic medical center hospital. © 2015, Wiley Periodicals, Inc.

Aspects of renal function in patients with colorectal cancer in a gastroenterology clinic of a county hospital in Western Romania.

PubMed

Velciov, Silvia; Hoinoiu, B; Hoinoiu, Teodora; Popescu, Alina; Gluhovschi, Cristina; Grădinaru, Oana; Popescu, Mădalină; Moţiu, Flavia; Timar, R; Gluhovschi, G H; Sporea, I

2013-01-01

Colorectal cancer represents the third cause of cancer. Since its detection in due time is important resolution, appropriate monitoring is mandatory. The present study deals with the relationship between colorectal cancer and renal function, as well as other associated risk factors. Chronic kidney disease (CKD) represents a risk factor of cancer, both in non-dialysed patients and especially in dialysed patients and in patients with renal transplant. It can get aggravated with cancer in general and particularly with colorectal cancer, partly related to the toxins that cannot be appropriately eliminated because of renal functional disturbances. At the same time, immunosuppressive therapy used for treating glomerular or secondary nephropathies represents an important risk factor of cancer. Some patients with colorectal cancer were found to present also impaired renal function, a fact whose significance is still little known. The object of the present paper is an analysis of the case records of a clinic of gastroenterology on the relationship between colorectal cancer and renal functional impairment. We found in the patients with colorectal cancer under study a glomerular filtration rate (GFR calculated with the EPI formula) of < 60 ml/min/1.73m2 in 31/180 patients, respectively 17.22% of the cases, a value that is similar to that in specialised literature. We also analysed associated risk factors that could be related to renal function impairment in these patients: age, gender, anaemia, diabetes mellitus and hypertension. These could represent, together with the colorectal cancer of the investigated patients, risk factors affecting on the one hand renal function, and on the other hand, potentially increasing the risk of cancer. Correction of these risk factors would have beneficial effects on patients. The relationship between renal functional impairment, respectively CKD, and colorectal cancer is to be regarded from the point of view of complex reciprocity: the impairment of the renal function is a factor of risk of colorectal cancer and colorectal cancer can influence renal function of these patients. This report of reciprocity based on important pathogenic mechanisms also interrelates with factors of risk consecutive to both renal function impairment and colorectal cancer.

Therapeutic Effects of Procainamide on Endotoxin-Induced Rhabdomyolysis in Rats

PubMed Central

Shih, Chih-Chin; Hii, Hiong-Ping; Tsao, Cheng-Ming; Chen, Shiu-Jen; Ka, Shuk-Man; Liao, Mei-Hui; Wu, Chin-Chen

2016-01-01

Overt systemic inflammatory response is a predisposing mechanism for infection-induced skeletal muscle damage and rhabdomyolysis. Aberrant DNA methylation plays a crucial role in the pathophysiology of excessive inflammatory response. The antiarrhythmic drug procainamide is a non-nucleoside inhibitor of DNA methyltransferase 1 (DNMT1) used to alleviate DNA hypermethylation. Therefore, we evaluated the effects of procainamide on the syndromes and complications of rhabdomyolysis rats induced by lipopolysaccharide (LPS). Rhabdomyolysis animal model was established by intravenous infusion of LPS (5 mg/kg) accompanied by procainamide therapy (50 mg/kg). During the experimental period, the changes of hemodynamics, muscle injury index, kidney function, blood gas, blood electrolytes, blood glucose, and plasma interleukin-6 (IL-6) levels were examined. Kidneys and lungs were exercised to analyze superoxide production, neutrophil infiltration, and DNMTs expression. The rats in this model showed similar clinical syndromes and complications of rhabdomyolysis including high levels of plasma creatine kinase, acute kidney injury, hyperkalemia, hypocalcemia, metabolic acidosis, hypotension, tachycardia, and hypoglycemia. The increases of lung DNMT1 expression and plasma IL-6 concentration were also observed in rhabdomyolysis animals induced by LPS. Treatment with procainamide not only inhibited the overexpression of DNMT1 but also diminished the overproduction of IL-6 in rhabdomyolysis rats. In addition, procainamide improved muscle damage, renal dysfunction, electrolytes disturbance, metabolic acidosis, hypotension, and hypoglycemia in the rats with rhabdomyolysis. Moreover, another DNMT inhibitor hydralazine mitigated hypoglycemia, muscle damage, and renal dysfunction in rhabdomyolysis rats. These findings reveal that therapeutic effects of procainamide could be based on the suppression of DNMT1 and pro-inflammatory cytokine in endotoxin-induced rhabdomyolysis. PMID:26918767

Therapeutic Effects of Procainamide on Endotoxin-Induced Rhabdomyolysis in Rats.

PubMed

Shih, Chih-Chin; Hii, Hiong-Ping; Tsao, Cheng-Ming; Chen, Shiu-Jen; Ka, Shuk-Man; Liao, Mei-Hui; Wu, Chin-Chen

2016-01-01

Overt systemic inflammatory response is a predisposing mechanism for infection-induced skeletal muscle damage and rhabdomyolysis. Aberrant DNA methylation plays a crucial role in the pathophysiology of excessive inflammatory response. The antiarrhythmic drug procainamide is a non-nucleoside inhibitor of DNA methyltransferase 1 (DNMT1) used to alleviate DNA hypermethylation. Therefore, we evaluated the effects of procainamide on the syndromes and complications of rhabdomyolysis rats induced by lipopolysaccharide (LPS). Rhabdomyolysis animal model was established by intravenous infusion of LPS (5 mg/kg) accompanied by procainamide therapy (50 mg/kg). During the experimental period, the changes of hemodynamics, muscle injury index, kidney function, blood gas, blood electrolytes, blood glucose, and plasma interleukin-6 (IL-6) levels were examined. Kidneys and lungs were exercised to analyze superoxide production, neutrophil infiltration, and DNMTs expression. The rats in this model showed similar clinical syndromes and complications of rhabdomyolysis including high levels of plasma creatine kinase, acute kidney injury, hyperkalemia, hypocalcemia, metabolic acidosis, hypotension, tachycardia, and hypoglycemia. The increases of lung DNMT1 expression and plasma IL-6 concentration were also observed in rhabdomyolysis animals induced by LPS. Treatment with procainamide not only inhibited the overexpression of DNMT1 but also diminished the overproduction of IL-6 in rhabdomyolysis rats. In addition, procainamide improved muscle damage, renal dysfunction, electrolytes disturbance, metabolic acidosis, hypotension, and hypoglycemia in the rats with rhabdomyolysis. Moreover, another DNMT inhibitor hydralazine mitigated hypoglycemia, muscle damage, and renal dysfunction in rhabdomyolysis rats. These findings reveal that therapeutic effects of procainamide could be based on the suppression of DNMT1 and pro-inflammatory cytokine in endotoxin-induced rhabdomyolysis.

Improved hemodynamic parameters in middle cerebral artery infarction after decompressive craniectomy.

PubMed

Amorim, Robson Luis; de Andrade, Almir Ferreira; Gattás, Gabriel S; Paiva, Wellingson Silva; Menezes, Marcos; Teixeira, Manoel Jacobsen; Bor-Seng-Shu, Edson

2014-05-01

Decompressive craniectomy (DC) reduces mortality and improves functional outcome in patients with malignant middle cerebral artery infarction. However, little is known regarding the impact of DC on cerebral hemodynamics. Therefore, our goal was to study the hemodynamic changes that may occur in patients with malignant middle cerebral artery infarction after DC and to assess their relationship with outcomes. Twenty-seven patients with malignant middle cerebral artery infarction who were treated with DC were studied. The perfusion CT hemodynamic parameters, mean transit time, cerebral blood flow, and cerebral blood volume were evaluated preoperatively and within the first 24 hours after DC. There was a global trend toward improved cerebral hemodynamics after DC. Preoperative and postoperative absolute mean transit times were associated with mortality at 6 months, and the ratio of post- and preoperative cerebral blood flow was significantly higher in patients with favorable outcomes than those with unfavorable outcomes. Patients who underwent surgery 48 hours after stroke, those with midline brain shift>10 mm, and those who were >55 years showed no significant improvement in any perfusion CT parameters. DC improves cerebral hemodynamics in patients with malignant middle cerebral artery infarction, and the level of improvement is related to outcome. However, some patients did not seem to experience any additional hemodynamic benefit, suggesting that perfusion CT may play a role as a prognostic tool in patients undergoing DC after ischemic stroke.

Echocardiographic parameters predicting acute hemodynamically significant mitral regurgitation during transfemoral transcatheter aortic valve replacement.

PubMed

Ito, Asahiro; Iwata, Shinichi; Mizutani, Kazuki; Nonin, Shinichi; Nishimura, Shinsuke; Takahashi, Yosuke; Yamada, Tokuhiro; Murakami, Takashi; Shibata, Toshihiko; Yoshiyama, Minoru

2018-03-01

Alteration in mitral valve morphology resulting from retrograde stiff wire entanglement sometimes causes hemodynamically significant acute mitral regurgitation (MR) during transfemoral transcatheter aortic valve replacement (TAVR). Little is known about the echocardiographic parameters related to hemodynamically significant acute MR. This study population consisted of 64 consecutive patients who underwent transfemoral TAVR. We defined hemodynamically significant acute MR as changes in the severity of MR with persistent hypotension (systolic blood pressure < 80-90 mm Hg or mean arterial pressure 30 mm Hg lower than baseline). Hemodynamically significant acute MR occurred in 5 cases (7.8%). Smaller left ventricular end-systolic diameter (LVDs), larger ratios of the coiled section of stiff wire tip to LVDs (wire-width/LVDs), and higher Wilkins score were significantly associated with hemodynamically significant acute MR (P < .05), whereas the parameters of functional MR (annular area, anterior-posterior diameter, tenting area, and coaptation length) were not. Moreover, when patients were divided into 4 groups according to wire-width/LVDs and Wilkins score, the group with the larger wire-width/LVDs and higher Wilkins score improved prediction rates (P < .05). Small left ventricle or wire oversizing and calcific mitral apparatus were predictive of hemodynamically significant acute MR. These findings are important for risk stratification, and careful monitoring using intraoperative transesophageal echocardiography may improve the safety in this population. © 2017, Wiley Periodicals, Inc.

On estimating intraventricular hemodynamic forces from endocardial dynamics: A comparative study with 4D flow MRI.

PubMed

Pedrizzetti, Gianni; Arvidsson, Per M; Töger, Johannes; Borgquist, Rasmus; Domenichini, Federico; Arheden, Håkan; Heiberg, Einar

2017-07-26

Intraventricular pressure gradients or hemodynamic forces, which are their global measure integrated over the left ventricular volume, have a fundamental importance in ventricular function. They may help revealing a sub-optimal cardiac function that is not evident in terms of tissue motion, which is naturally heterogeneous and variable, and can influence cardiac adaptation. However, hemodynamic forces are not utilized in clinical cardiology due to the unavailability of simple non-invasive measurement tools. Hemodynamic forces depend on the intraventricular flow; nevertheless, most of them are imputable to the dynamics of the endocardial flow boundary and to the exchange of momentum across the mitral and aortic orifices. In this study, we introduce a simplified model based on first principles of fluid dynamics that allows estimating hemodynamic forces without knowing the velocity field inside the LV. The model is validated with 3D phase-contrast MRI (known as 4D flow MRI) in 15 subjects, (5 healthy and 10 patients) using the endocardial surface reconstructed from the three standard long-axis projections. Results demonstrate that the model provides consistent estimates for the base-apex component (mean correlation coefficient r=0.77 for instantaneous values and r=0.88 for root mean square) and good estimates of the inferolateral-anteroseptal component (r=0.50 and 0.84, respectively). The present method represents a potential integration to the existing ones quantifying endocardial deformation in MRI and echocardiography to add a physics-based estimation of the corresponding hemodynamic forces. These could help the clinician to early detect sub-clinical diseases and differentiate between different cardiac dysfunctional states. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of Combined General/Epidural Anesthesia on Hemodynamics, Respiratory Function, and Stress Hormone Levels in Patients with Ovarian Neoplasm Undergoing Laparoscopy.

PubMed

Xu, Qiang; Zhang, Hao; Zhu, Yan-Mei; Shi, Nian-Jun

2016-11-08

BACKGROUND The aim of this study was to evaluate the influence of combined general/epidural anesthesia (GEA) on hemodynamics, respiratory function and stress hormone levels in patients with ovarian neoplasm undergoing laparoscopy. MATERIAL AND METHODS A total of 177 patients with ovarian neoplasm (screened by inclusion/exclusion criteria) receiving laparoscopy were divided into groups G (general anesthesia alone), L1.0 (GEA with 1.0% lidocaine), and L1.5 (GEA with 1.5% lidocaine). Hemodynamics, respiratory parameters and stress hormone levels in the 3 groups were recorded and analyzed. RESULTS Hemodynamic indexes and PaO2/PaCO2 in group L1.0 showed no differences at each time point (all P>0.05). At the end of anesthesia tracheal intubation (T1), 10 min after pneumoperitoneum (T2) and the end of anesthesia tracheal extubation (T3), there were significant differences in hemodynamic indexes, respiratory parameters, epinephrine (E), and noradrenalin (NE) of group G/L1.5, compared with before anesthesia induction (T0) (all P<0.05). Compared with group G, there were big differences in dosage of anesthetics (sufentanil, vecuronium, and propofol) and pharmaceutic adjuvants (ephedrine, atropine, and nitroglycerin), postoperative recovery time, extubation time, and incidence of agitation in group L1.0/L1.5 (all P<0.05). CONCLUSIONS GEA can improve the quality and efficiency in laparoscopy for ovarian neoplasm, with the advantages of reduced anesthetics dosage, satisfactory postoperative analgesia, maintained hemodynamic stability, excellent uterine relaxation, and reduced time of anesthesia induction, surgery, recovery, and extubation. In addition, compared with group L1.5, group L1.0 was more secure and worthy of clinical promotion in laparoscopy.

Interaction between renal function and percutaneous edge-to-edge mitral valve repair using MitraClip.

PubMed

Kaneko, Hidehiro; Neuss, Michael; Schau, Thomas; Weissenborn, Jens; Butter, Christian

2017-02-01

MitraClip (MC; Abbott Vascular, Menlo Park, CA, USA) is a treatment option for mitral regurgitation. Renal dysfunction is closely associated with cardiovascular disease. However, the influence of renal function in MC remains not fully understood. In this study, we aimed to clarify the association between renal function and MC. We examined 206 consecutive patients who underwent MC and divided patients into 3 groups according to estimated glomerular filtration rate (eGFR), normal eGFR (≥60mL/min/1.73m 2 ) (n=70), mild chronic kidney disease (CKD) (30-59mL/min/1.73m 2 ) (n=106), and severe CKD (<30mL/min/1.73m 2 ) (n=30). N-terminal pro-B type natriuretic peptide (NT-pro BNP) levels increased with decreasing eGFR. Kaplan-Meier curves revealed that the long-term survival rate significantly decreased with eGFR. After adjustment with the covariates, severe CKD was still associated with mortality. Improved renal function was observed in 30% and associated with baseline lower NT-pro BNP levels. Patients with improved renal function had higher chronic phase survival rate. Renal dysfunction is common in MC patients and the survival rate decreased with eGFR in association with increased NT-pro BNP levels. MC may improve renal function in approximately 30% of MC patients. Improved renal function is associated with lower NT-pro BNP levels and results in satisfactory prognosis. These results implies a close association between renal function and MC treatment. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Assessment of renal function and electrolytes in patients with thyroid dysfunction in Addis Ababa, Ethiopia: a cross sectional study.

PubMed

Abebe, Nardos; Kebede, Tedla; Wolde, Mistire

2016-01-01

Studies demonstrated that abnormal thyroid functions may result in decreased or increased kidney size, kidney weight, and affect renal functions. In this regard, studies on the association of abnormal thyroid functions and renal function tests are scarcely found in Ethiopia. To assess renal function and electrolytes in patients with thyroid dysfunction, in Addis Ababa, Ethiopia. Cross sectional study was conducted from March 21/2015-May 27/2015 at Arsho Advanced Medical Laboratory. During the study period, 71 patients with thyroid dysfunction were eligible, and socio demographic data collected by structured questionnaire. Then blood sample was collected for thyroid function tests, renal function and blood electrolyte analysis. The collected data was analyzed by SPSS version 20. ANOVA and binary logistic regression were employed to evaluate the mean deference and associations of thyroid hormone with renal function and electrolyte balances. Among the renal function tests, serum uric acid, and creatinine mean values were significantly decreased in hyperthyroid patients; whereas, eGFR mean value was significantly increased in hyperthyroid study patients (P<0.05). Meanwhile, from the electrolyte measurements made, only the mean serum sodium value was significantly increased in hyperthyroid study participants. Binary logistic regression analysis on the association of thyroid dysfunction with electrolyte balance and renal function tests indicated that serum sodium, creatinine, eGFR values and hyperthyroidism have a statistical significant association at AOR 95% CI of 0.141(0.033-0.593, P=0.008); 16.236(3.481-75.739, P=0.001), and 13.797(3.261-58.67, P=0.001) respectively. The current study reveals, thyroid abnormalities may lead to renal function alterations and also may disturb electrolyte balance. Knowledge of this significant association has worthwhile value for clinicians, to manage their patients' optimally.

Skin temperature and core-peripheral temperature gradient as markers of hemodynamic status in critically ill patients: a review.

PubMed

Schey, Bernadette M; Williams, David Y; Bucknall, Tracey

2010-01-01

To examine the evidential basis underpinning the monitoring of skin temperature and core-peripheral temperature gradient as elements of hemodynamic assessment in critically ill and adult cardiac surgical patients. Twenty-six studies examining the efficacy of skin temperature or temperature gradient as markers of hemodynamic status were selected as part of an integrative review. Evidence pertaining to the efficacy of these parameters as markers of cardiac function is equivocal and has not been well appraised in the adult cardiac surgical population. Skin temperature and systemic vascular resistance are also affected by factors other than cardiac output. Skin temperature and core-peripheral temperature gradient should not be considered in isolation from other hemodynamic parameters when assessing cardiac status until they are validated by further large-scale prospective studies. 2010. Published by Mosby, Inc.

Cerebral Hemodynamics During Exercise and Recovery in Heart Transplant Recipients.

PubMed

Gayda, Mathieu; Desjardins, Audrey; Lapierre, Gabriel; Dupuy, Olivier; Fraser, Sarah; Bherer, Louis; Juneau, Martin; White, Michel; Gremeaux, Vincent; Labelle, Véronique; Nigam, Anil

2016-04-01

The aims of this work were (1) to compare cerebral oxygenation-perfusion (COP), central hemodynamics, and peak oxygen uptake (V˙o2peak) in heart transplant recipients (HTRs) vs age-matched healthy controls (AMHCs) during exercise and recovery and (2) to study the relationships between COP, central hemodynamics, and V˙o2peak in HTRs and AMHCs. Twenty-six HTRs (3 women) and 27 AMHCs (5 women) were recruited. Maximal cardiopulmonary function (gas exchange analysis), cardiac hemodynamics (impedance cardiography), and left frontal COP (near-infrared spectroscopy) were measured continuously during and after a maximal ergocycle (Ergoline 800S, Bitz, Germany) test. Compared with AMHCs, HTRs had lower V˙o2peak, maximal cardiac index (CImax), and maximal ventilatory variables (P < 0.05). COP was lower during exercise (oxyhemoglobin [ΔO2Hb], 50% and 75% of V˙O2peak, total hemoglobin [ΔtHb], 100% of V˙O2peak; P < 0.05), and recovery in HTRs (ΔO2Hb, minutes 2-5; ΔtHb, minutes 1-5; P < 0.05) compared with AMHCs. End-tidal pressure of CO2 was lower during exercise compared with that in AMHCs (P < 0.0001). In HTRs, CImax was positively correlated with exercise cerebral hemodynamics (R = 0.54-0.60; P < 0.01). In HTRs, COP was reduced during exercise and recovery compared with that in AMHCs, potentially because of a combination of blunted cerebral vasodilation by CO2, cerebrovascular dysfunction, reduced cardiac function, and medication. The impaired V˙O2peak observed in HTRs was mainly caused by reduced maximal ventilation and CI. In HTRs, COP is impaired and is correlated with cardiac function, potentially impacting cognitive function. Therefore, we need to study which interventions (eg, exercise training) are most effective for improving or normalizing (or both) COP during and after exercise in HTRs. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

A-1048400 is a novel, orally active, state-dependent neuronal calcium channel blocker that produces dose-dependent antinociception without altering hemodynamic function in rats.

PubMed

Scott, Victoria E; Vortherms, Timothy A; Niforatos, Wende; Swensen, Andrew M; Neelands, Torben; Milicic, Ivan; Banfor, Patricia N; King, Andrew; Zhong, Chengmin; Simler, Gricelda; Zhan, Cenchen; Bratcher, Natalie; Boyce-Rustay, Janel M; Zhu, Chang Z; Bhatia, Pramila; Doherty, George; Mack, Helmut; Stewart, Andrew O; Jarvis, Michael F

2012-02-01

Blockade of voltage-gated Ca²⁺ channels on sensory nerves attenuates neurotransmitter release and membrane hyperexcitability associated with chronic pain states. Identification of small molecule Ca²⁺ channel blockers that produce significant antinociception in the absence of deleterious hemodynamic effects has been challenging. In this report, two novel structurally related compounds, A-686085 and A-1048400, were identified that potently block N-type (IC₅₀=0.8 μM and 1.4 μM, respectively) and T-type (IC₅₀=4.6 μM and 1.2 μM, respectively) Ca²⁺ channels in FLIPR based Ca²⁺ flux assays. A-686085 also potently blocked L-type Ca²⁺ channels (EC₅₀=0.6 μM), however, A-1048400 was much less active in blocking this channel (EC₅₀=28 μM). Both compounds dose-dependently reversed tactile allodynia in a model of capsaicin-induced secondary hypersensitivity with similar potencies (EC₅₀=300-365 ng/ml). However, A-686085 produced dose-related decreases in mean arterial pressure at antinociceptive plasma concentrations in the rat, while A-1048400 did not significantly alter hemodynamic function at supra-efficacious plasma concentrations. Electrophysiological studies demonstrated that A-1048400 blocks native N- and T-type Ca²⁺ currents in rat dorsal root ganglion neurons (IC₅₀=3.0 μM and 1.6 μM, respectively) in a voltage-dependent fashion. In other experimental pain models, A-1048400 dose-dependently attenuated nociceptive, neuropathic and inflammatory pain at doses that did not alter psychomotor or hemodynamic function. The identification of A-1048400 provides further evidence that voltage-dependent inhibition of neuronal Ca²⁺ channels coupled with pharmacological selectivity vs. L-type Ca²⁺ channels can provide robust antinociception in the absence of deleterious effects on hemodynamic or psychomotor function. Copyright © 2011 Elsevier Inc. All rights reserved.

Efficient solution methodology for calibrating the hemodynamic model using functional Magnetic Resonance Imaging (fMRI) measurements.

PubMed

Zambri, Brian; Djellouli, Rabia; Laleg-Kirati, Taous-Meriem

2015-08-01

Our aim is to propose a numerical strategy for retrieving accurately and efficiently the biophysiological parameters as well as the external stimulus characteristics corresponding to the hemodynamic mathematical model that describes changes in blood flow and blood oxygenation during brain activation. The proposed method employs the TNM-CKF method developed in [1], but in a prediction/correction framework. We present numerical results using both real and synthetic functional Magnetic Resonance Imaging (fMRI) measurements to highlight the performance characteristics of this computational methodology.

Reduction of severe mitral regurgitation with the MitraClip system improves renal function in two patients presenting with acute kidney injury and progressive renal failure due to cardio renal syndrome.

PubMed

Asdonk, T; Nickenig, G; Hammerstingl, C

2014-10-01

Mitral regurgitation (MR) is a frequent valve disorder in elderly patients, often accompanied by multiple comorbidities such as renal impairment. In these patients percutaneous mitral valve (MV) repair has become an established treatment option but the role of MR on renal dysfunction is not yet well defined. We here report on two cases presenting with severe MR and progressive renal failure caused by cardio renal syndrome, in which percutaneous MV treatment with the MitraClip system significantly improved renal function. These findings suggest that interventional MV repair can prevent progression of renal deterioration in patients suffering from combined advanced heart and renal failure. Further clinical studies are necessary to support our finding and to answer the question whether optimizing renal function by implantation of the MitraClip device is also of prognostic relevance in these patients. © 2014 Wiley Periodicals, Inc.

Quantitative analysis of the renal aging in rats. Stereological study.

PubMed

Melchioretto, Eduardo Felippe; Zeni, Marcelo; Veronez, Djanira Aparecida da Luz; Martins, Eduardo Lopes; Fraga, Rogério de

2016-05-01

To evaluate the renal function and the renal histological alterations through the stereology and morphometrics in rats submitted to the natural process of aging. Seventy two Wistar rats, divided in six groups. Each group was sacrificed in a different age: 3, 6, 9, 12, 18 and 24 months. It was performed right nephrectomy, stereological and morphometric analysis of the renal tissue (renal volume and weight, density of volume (Vv[glom]) and numerical density (Nv[glom]) of the renal glomeruli and average glomerular volume (Vol[glom])) and also it was evaluated the renal function for the dosage of serum creatinine and urea. There was significant decrease of the renal function in the oldest rats. The renal volume presented gradual increase during the development of the rats with the biggest values registered in the group of animals at 12 months of age and significant progressive decrease in older animals. Vv[glom] presented statistically significant gradual reduction between the groups and the Nv[glom] also decreased significantly. The renal function proved to be inferior in senile rats when compared to the young rats. The morphometric and stereological analysis evidenced renal atrophy, gradual reduction of the volume density and numerical density of the renal glomeruli associated to the aging process.

Central circulatory hemodynamics as a function of gravitational stress

NASA Technical Reports Server (NTRS)

Latham, Rick D.; White, C. D.; Fanton, J. W.; Owens, R. W.; Barber, J. F.; Lewkowski, B. E.; Goff, O. T.

1991-01-01

This study focuses on an evaluation of the central hemodynamics in a nonhuman primate model to variations in gravitational states. The baboon, phylogenectically close to man, was chosen as the human surrogate. The study environments selected are head-down and head-up tilt in the physiology laboratory, centrifugation to test hypergravic stress, and parabolic flights to test transient acute responses to microgravity.

Staging Hemodynamic Failure With Blood Oxygen-Level-Dependent Functional Magnetic Resonance Imaging Cerebrovascular Reactivity: A Comparison Versus Gold Standard (15O-)H2O-Positron Emission Tomography.

PubMed

Fierstra, Jorn; van Niftrik, Christiaan; Warnock, Geoffrey; Wegener, Susanne; Piccirelli, Marco; Pangalu, Athina; Esposito, Giuseppe; Valavanis, Antonios; Buck, Alfred; Luft, Andreas; Bozinov, Oliver; Regli, Luca

2018-03-01

Increased stroke risk correlates with hemodynamic failure, which can be assessed with ( 15 O-)H 2 O positron emission tomography (PET) cerebral blood flow (CBF) measurements. This gold standard technique, however, is not established for routine clinical imaging. Standardized blood oxygen-level-dependent (BOLD) functional magnetic resonance imaging+CO 2 is a noninvasive and potentially widely applicable tool to assess whole-brain quantitative cerebrovascular reactivity (CVR). We examined the agreement between the 2 imaging modalities and hypothesized that quantitative CVR can be a surrogate imaging marker to assess hemodynamic failure. Nineteen data sets of subjects with chronic cerebrovascular steno-occlusive disease (age, 60±11 years; 4 women) and unilaterally impaired perfusion reserve on Diamox-challenged ( 15 O-)H 2 O PET were studied and compared with a standardized BOLD functional magnetic resonance imaging+CO 2 examination within 6 weeks (8±19 days). Agreement between quantitative CBF- and CVR-based perfusion reserve was assessed. Hemodynamic failure was staged according to PET findings: stage 0: normal CBF, normal perfusion reserve; stage I: normal CBF, decreased perfusion reserve; and stage II: decreased CBF, decreased perfusion reserve. The BOLD CVR data set of the same subjects was then matched to the corresponding stage of hemodynamic failure. PET-based stage I versus stage II could also be clearly separated with BOLD CVR measurements (CVR for stage I 0.11 versus CVR for stage II -0.03; P <0.01). Hemispheric and middle cerebral artery territory difference analyses (ie, affected versus unaffected side) showed a significant correlation for CVR impairment in the affected hemisphere and middle cerebral artery territory ( P <0.01, R 2 =0.47 and P =0.02, R 2 = 0.25, respectively). BOLD CVR corresponded well to CBF perfusion reserve measurements obtained with ( 15 O-)H 2 O-PET, especially for detecting hemodynamic failure in the affected hemisphere and middle cerebral artery territory and for identifying hemodynamic failure stage II. BOLD CVR may, therefore, be considered for prospective studies assessing stroke risk in patients with chronic cerebrovascular steno-occlusive disease, in particular because it can potentially be implemented in routine clinical imaging. © 2018 American Heart Association, Inc.

Time-resolved absorption and hemoglobin concentration difference maps: a method to retrieve depth-related information on cerebral hemodynamics.

NASA Astrophysics Data System (ADS)

Montcel, Bruno; Chabrier, Renée; Poulet, Patrick

2006-12-01

Time-resolved diffuse optical methods have been applied to detect hemodynamic changes induced by cerebral activity. We describe a near infrared spectroscopic (NIRS) reconstruction free method which allows retrieving depth-related information on absorption variations. Variations in the absorption coefficient of tissues have been computed over the duration of the whole experiment, but also over each temporal step of the time-resolved optical signal, using the microscopic Beer-Lambert law.Finite element simulations show that time-resolved computation of the absorption difference as a function of the propagation time of detected photons is sensitive to the depth profile of optical absorption variations. Differences in deoxyhemoglobin and oxyhemoglobin concentrations can also be calculated from multi-wavelength measurements. Experimental validations of the simulated results have been obtained for resin phantoms. They confirm that time-resolved computation of the absorption differences exhibited completely different behaviours, depending on whether these variations occurred deeply or superficially. The hemodynamic response to a short finger tapping stimulus was measured over the motor cortex and compared to experiments involving Valsalva manoeuvres. Functional maps were also calculated for the hemodynamic response induced by finger tapping movements.

Time-resolved absorption and hemoglobin concentration difference maps: a method to retrieve depth-related information on cerebral hemodynamics.

PubMed

Montcel, Bruno; Chabrier, Renée; Poulet, Patrick

2006-12-11

Time-resolved diffuse optical methods have been applied to detect hemodynamic changes induced by cerebral activity. We describe a near infrared spectroscopic (NIRS) reconstruction free method which allows retrieving depth-related information on absorption variations. Variations in the absorption coefficient of tissues have been computed over the duration of the whole experiment, but also over each temporal step of the time-resolved optical signal, using the microscopic Beer-Lambert law.Finite element simulations show that time-resolved computation of the absorption difference as a function of the propagation time of detected photons is sensitive to the depth profile of optical absorption variations. Differences in deoxyhemoglobin and oxyhemoglobin concentrations can also be calculated from multi-wavelength measurements. Experimental validations of the simulated results have been obtained for resin phantoms. They confirm that time-resolved computation of the absorption differences exhibited completely different behaviours, depending on whether these variations occurred deeply or superficially. The hemodynamic response to a short finger tapping stimulus was measured over the motor cortex and compared to experiments involving Valsalva manoeuvres. Functional maps were also calculated for the hemodynamic response induced by finger tapping movements.

Noise reduction in functional near-infrared spectroscopy signals by independent component analysis

NASA Astrophysics Data System (ADS)

Santosa, Hendrik; Jiyoun Hong, Melissa; Kim, Sung-Phil; Hong, Keum-Shik

2013-07-01

Functional near-infrared spectroscopy (fNIRS) is used to detect concentration changes of oxy-hemoglobin and deoxy-hemoglobin in the human brain. The main difficulty entailed in the analysis of fNIRS signals is the fact that the hemodynamic response to a specific neuronal activation is contaminated by physiological and instrument noises, motion artifacts, and other interferences. This paper proposes independent component analysis (ICA) as a means of identifying the original hemodynamic response in the presence of noises. The original hemodynamic response was reconstructed using the primary independent component (IC) and other, less-weighting-coefficient ICs. In order to generate experimental brain stimuli, arithmetic tasks were administered to eight volunteer subjects. The t-value of the reconstructed hemodynamic response was improved by using the ICs found in the measured data. The best t-value out of 16 low-pass-filtered signals was 37, and that of the reconstructed one was 51. Also, the average t-value of the eight subjects' reconstructed signals was 40, whereas that of all of their low-pass-filtered signals was only 20. Overall, the results showed the applicability of the ICA-based method to noise-contamination reduction in brain mapping.

Real-time hemodynamic response and mitochondrial function changes with intracarotid mannitol injection

PubMed Central

Joshi, Shailendra; Singh-Moon, Rajinder; Wang, Mei; Bruce, Jeffrey N.; Bigio, Irving J.; Mayevsky, Avraham

2014-01-01

Disruption of blood brain barrier (BBB) is used to enhance chemotherapeutic drug delivery. The purpose of this study was to understand the time course of hemodynamic and metabolic response to intraarterial (IA) mannitol infusions in order to optimize the delivery of drugs for treating brain tumors. Principal results We compared hemodynamic response, EEG changes, and mitochondrial function as judged by relative changes in tissue NADH concentrations, after intracarotid (IC) infusion of equal volumes of normal saline and mannitol in our rabbit IC drug delivery model. We observed significantly greater, though transient, hyperemic response to IC infusion of mannitol compared to normal saline. Infusion of mannitol also resulted in a greater increase in tissue NADH concentrations relative to the baseline. These hemodynamic, and metabolic changes returned to baseline within 5 min of mannitol injection. Conclusion Significant, though transient, changes in blood flow and brain metabolism occur with IA mannitol infusion. The observed transient hyperemia would suggest that intravenous (IV) chemotherapy should be administered either just before, or concurrent with IA mannitol injections. On the other hand, IA chemotherapy should be delayed until the peak hyperemic response has subsided. PMID:24440631

Nephrotic range proteinuria as a strong risk factor for rapid renal function decline during pre-dialysis phase in type 2 diabetic patients with severely impaired renal function.

PubMed

Kitai, Yuichiro; Doi, Yohei; Osaki, Keisuke; Sugioka, Sayaka; Koshikawa, Masao; Sugawara, Akira

2015-12-01

Proteinuria is an established risk factor for progression of renal disease, including diabetic nephropathy. The predictive power of proteinuria, especially nephrotic range proteinuria, for progressive renal deterioration has been well demonstrated in diabetic patients with normal to relatively preserved renal function. However, little is known about the relationship between severity of proteinuria and renal outcome in pre-dialysis diabetic patients with severely impaired renal function. 125 incident dialysis patients with type 2 diabetes were identified. This study was aimed at retrospectively evaluating the impact of nephrotic range proteinuria (urinary protein-creatinine ratio above 3.5 g/gCr) on renal function decline during the 3 months just prior to dialysis initiation. In total, 103 patients (82.4 %) had nephrotic range proteinuria. The median rate of decline in estimated glomerular filtration rate (eGFR) in this study population was 0.98 (interquartile range 0.51-1.46) ml/min/1.73 m(2) per month. Compared to patients without nephrotic range proteinuria, patients with nephrotic range proteinuria showed significantly faster renal function decline (0.46 [0.24-1.25] versus 1.07 [0.64-1.54] ml/min/1.73 m(2) per month; p = 0.007). After adjusting for gender, age, systolic blood pressure, serum albumin, calcium-phosphorus product, hemoglobin A1c, and use of an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, patients with nephrotic range proteinuria showed a 3.89-fold (95 % CI 1.08-14.5) increased risk for rapid renal function decline defined as a decline in eGFR ≥0.5 ml/min/1.73 m(2) per month. Nephrotic range proteinuria is the predominant renal risk factor in type 2 diabetic patients with severely impaired renal function receiving pre-dialysis care.

[Brainstem auditory evoked potentials in neurophysiological assessment of brain stem dysfunction in patients with atherostenosis of vertebral arteries].

PubMed

Maksimova, M Yu; Sermagambetova, Zh N; Skrylev, S I; Fedin, P A; Koshcheev, A Yu; Shchipakin, V L; Sinicyn, I A

To assess brain stem dysfunction in patients with hemodynamically significant stenosis of vertebral arteries (VA) using short latency brainstem auditory evoked potentials (BAEP). The study group included 50 patients (mean age 64±6 years) with hemodynamically significant extracranial VA stenosis. Patients with hemodynamically significant extracranial VA stenosis had BAEP abnormalities including the elongation of interpeak intervals I-V and peak V latency as well as the reduction of peak I amplitude. After transluminal balloon angioplasty with stenting of VA stenoses, there was a shortening of peak V latency compared to the preoperative period that reflected the improvement of brain stem conductive functions. Atherostenosis of vertebral arteries is characterized by the signs of brain stem dysfunction, predominantly in the pontomesencephal brain stem. After transluminal balloon angioplasty with stenting of VA, the improvement of brain stem conductive functions was observed.

Effects of renal function on pharmacokinetics and pharmacodynamics of lesinurad in adult volunteers.

PubMed

Gillen, Michael; Valdez, Shakti; Zhou, Dongmei; Kerr, Bradley; Lee, Caroline A; Shen, Zancong

2016-01-01

Lesinurad is a selective uric acid reabsorption inhibitor approved for the treatment of gout in combination with a xanthine oxidase inhibitor (XOI) in patients who have not achieved target serum uric acid (sUA) levels with an XOI alone. Most people with gout have chronic kidney disease. The pharmacokinetics, pharmacodynamics, and safety of lesinurad were assessed in subjects with impaired renal function. Two Phase I, multicenter, open-label, single-dose studies enrolled subjects with normal renal function (estimated creatinine clearance [eCrCl] >90 mL/min; N=12) or mild (eCrCl 60-89 mL/min; N=8), moderate (eCrCl 30-59 mL/min; N=16), or severe (eCrCl <30 mL/min; N=6) renal impairment. Subjects were given a single oral lesinurad dose of 200 mg (N=24) or 400 mg (N=18). Blood and urine samples were analyzed for plasma lesinurad concentrations and serum and urine uric acid concentrations. Safety was assessed by adverse events and laboratory data. Mild, moderate, and severe renal impairment increased lesinurad plasma area under the plasma concentration-time curve by 34%, 54%-65%, and 102%, respectively. Lesinurad plasma C max was unaffected by renal function status. Lower renal clearance and urinary excretion of lesinurad were associated with the degree of renal impairment. The sUA-lowering effect of a single dose of lesinurad was similar between mild renal impairment and normal function, reduced in moderate impairment, and greatly diminished in severe impairment. Lesinurad increased urinary urate excretion in normal function and mild renal impairment; the increase was less with moderate or severe renal impairment. Lesinurad was well tolerated by all subjects. Lesinurad exposure increased with decreasing renal function; however, the effects of lesinurad on sUA were attenuated in moderate to severe renal impairment.

Genomic integration of ERRγ-HNF1β regulates renal bioenergetics and prevents chronic kidney disease.

PubMed

Zhao, Juanjuan; Lupino, Katherine; Wilkins, Benjamin J; Qiu, Chengxiang; Liu, Jian; Omura, Yasuhiro; Allred, Amanda L; McDonald, Caitlin; Susztak, Katalin; Barish, Grant D; Pei, Liming

2018-05-22

Mitochondrial dysfunction is increasingly recognized as a critical determinant of both hereditary and acquired kidney diseases. However, it remains poorly understood how mitochondrial metabolism is regulated to support normal kidney function and how its dysregulation contributes to kidney disease. Here, we show that the nuclear receptor estrogen-related receptor gamma (ERRγ) and hepatocyte nuclear factor 1 beta (HNF1β) link renal mitochondrial and reabsorptive functions through coordinated epigenomic programs. ERRγ directly regulates mitochondrial metabolism but cooperatively controls renal reabsorption via convergent binding with HNF1β. Deletion of ERRγ in renal epithelial cells (RECs), in which it is highly and specifically expressed, results in severe renal energetic and reabsorptive dysfunction and progressive renal failure that recapitulates phenotypes of animals and patients with HNF1β loss-of-function gene mutations. Moreover, ERRγ expression positively correlates with renal function and is decreased in patients with chronic kidney disease (CKD). REC-ERRγ KO mice share highly overlapping renal transcriptional signatures with human patients with CKD. Together these findings reveal a role for ERRγ in directing independent and HNF1β-integrated programs for energy production and use essential for normal renal function and the prevention of kidney disease.

RENAL MICROVASCULAR DISEASE DETERMINES THE RESPONSES TO REVASCULARIZATION IN EXPERIMENTAL RENOVASCULAR DISEASE

PubMed Central

Chade, Alejandro R.; Kelsen, Silvia

2011-01-01

Background Percutaneous trasluminal renal angioplasty (PTRA) is the most frequent therapeutic approach to resolve renal artery stenosis (RAS). However, renal function recovers in only 30% of the cases. The causes of these poor outcomes are still unknown. We hypothesize that preserving the renal microcirculation distal to RAS will improve the responses to PTRA. Methods and Results RAS was induced in 28 pigs. In 14, vascular endothelial growth factor (VEGF)-165 was infused intra-renally (RAS+VEGF, 0.05 µg/kg). Single-kidney function was assessed in all pigs in vivo using ultra-fast CT after 6 weeks. Half of the RAS/RAS+VEGF completed their observation, and the other half underwent PTRA, VEGF was repeated, and CT studies repeated 4 weeks later. Pigs were then euthanized, the stenotic kidney removed, renal microvascular (MV) architecture reconstructed ex-vivo using 3D micro-CT, and renal fibrosis quantified. Degree of RAS and hypertension were similar in RAS and RAS+VEGF. Renal function and MV density were decreased in RAS but improved in RAS+VEGF. PTRA largely resolved RAS, but the improvements of hypertension and renal function were greater in RAS+VEGF+PTRA than in RAS+PTRA, accompanied by a 34% increase in MV density and decreased fibrosis. Conclusion Preservation of the MV architecture and function in the stenotic kidney improved the responses to PTRA, indicating that renal MV integrity plays a role in determining the responses to PTRA. This study indicates that damage and early loss of renal MV is an important determinant of the progression of renal injury in RAS and instigates often irreversible damage. PMID:20587789