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Sample records for renal tubular damage

  1. Tubular Overexpression of Gremlin Induces Renal Damage Susceptibility in Mice

    PubMed Central

    Droguett, Alejandra; Krall, Paola; Burgos, M. Eugenia; Valderrama, Graciela; Carpio, Daniel; Ardiles, Leopoldo; Rodriguez-Diez, Raquel; Kerr, Bredford; Walz, Katherina; Ruiz-Ortega, Marta; Egido, Jesus; Mezzano, Sergio

    2014-01-01

    A growing number of patients are recognized worldwide to have chronic kidney disease. Glomerular and interstitial fibrosis are hallmarks of renal progression. However, fibrosis of the kidney remains an unresolved challenge, and its molecular mechanisms are still not fully understood. Gremlin is an embryogenic gene that has been shown to play a key role in nephrogenesis, and its expression is generally low in the normal adult kidney. However, gremlin expression is elevated in many human renal diseases, including diabetic nephropathy, pauci-immune glomerulonephritis and chronic allograft nephropathy. Several studies have proposed that gremlin may be involved in renal damage by acting as a downstream mediator of TGF-β. To examine the in vivo role of gremlin in kidney pathophysiology, we generated seven viable transgenic mouse lines expressing human gremlin (GREM1) specifically in renal proximal tubular epithelial cells under the control of an androgen-regulated promoter. These lines demonstrated 1.2- to 200-fold increased GREM1 expression. GREM1 transgenic mice presented a normal phenotype and were without proteinuria and renal function involvement. In response to the acute renal damage cause by folic acid nephrotoxicity, tubule-specific GREM1 transgenic mice developed increased proteinuria after 7 and 14 days compared with wild-type treated mice. At 14 days tubular lesions, such as dilatation, epithelium flattening and hyaline casts, with interstitial cell infiltration and mild fibrosis were significantly more prominent in transgenic mice than wild-type mice. Tubular GREM1 overexpression was correlated with the renal upregulation of profibrotic factors, such as TGF-β and αSMA, and with increased numbers of monocytes/macrophages and lymphocytes compared to wild-type mice. Taken together, our results suggest that GREM1-overexpressing mice have an increased susceptibility to renal damage, supporting the involvement of gremlin in renal damage progression. This

  2. Tubular overexpression of gremlin induces renal damage susceptibility in mice.

    PubMed

    Droguett, Alejandra; Krall, Paola; Burgos, M Eugenia; Valderrama, Graciela; Carpio, Daniel; Ardiles, Leopoldo; Rodriguez-Diez, Raquel; Kerr, Bredford; Walz, Katherina; Ruiz-Ortega, Marta; Egido, Jesus; Mezzano, Sergio

    2014-01-01

    A growing number of patients are recognized worldwide to have chronic kidney disease. Glomerular and interstitial fibrosis are hallmarks of renal progression. However, fibrosis of the kidney remains an unresolved challenge, and its molecular mechanisms are still not fully understood. Gremlin is an embryogenic gene that has been shown to play a key role in nephrogenesis, and its expression is generally low in the normal adult kidney. However, gremlin expression is elevated in many human renal diseases, including diabetic nephropathy, pauci-immune glomerulonephritis and chronic allograft nephropathy. Several studies have proposed that gremlin may be involved in renal damage by acting as a downstream mediator of TGF-β. To examine the in vivo role of gremlin in kidney pathophysiology, we generated seven viable transgenic mouse lines expressing human gremlin (GREM1) specifically in renal proximal tubular epithelial cells under the control of an androgen-regulated promoter. These lines demonstrated 1.2- to 200-fold increased GREM1 expression. GREM1 transgenic mice presented a normal phenotype and were without proteinuria and renal function involvement. In response to the acute renal damage cause by folic acid nephrotoxicity, tubule-specific GREM1 transgenic mice developed increased proteinuria after 7 and 14 days compared with wild-type treated mice. At 14 days tubular lesions, such as dilatation, epithelium flattening and hyaline casts, with interstitial cell infiltration and mild fibrosis were significantly more prominent in transgenic mice than wild-type mice. Tubular GREM1 overexpression was correlated with the renal upregulation of profibrotic factors, such as TGF-β and αSMA, and with increased numbers of monocytes/macrophages and lymphocytes compared to wild-type mice. Taken together, our results suggest that GREM1-overexpressing mice have an increased susceptibility to renal damage, supporting the involvement of gremlin in renal damage progression. This

  3. TLR4 promotes fibrosis but attenuates tubular damage in progressive renal injury.

    PubMed

    Pulskens, Wilco P; Rampanelli, Elena; Teske, Gwendoline J; Butter, Loes M; Claessen, Nike; Luirink, Ilse K; van der Poll, Tom; Florquin, Sandrine; Leemans, Jaklien C

    2010-08-01

    Toll-like receptors (TLRs) can orchestrate an inflammatory response upon activation by pathogen-associated motifs and release of endogenous stress ligands during tissue injury. The kidney constitutively expresses most TLRs, including TLR4. The function of TLR4 during the inflammation, tubular atrophy, and fibrosis that accompany progressive renal injury is unknown. Here, we subjected wild-type (WT) and TLR4-deficient mice to unilateral ureteral obstruction and observed elevated levels of TLR4 mRNA in the kidney after obstruction. One day after unilateral ureteral obstruction, TLR4-deficient mice had fewer proliferating tubular epithelial cells and more tubular damage than WT mice; however, TLR4-deficient mice developed considerably less renal fibrosis despite decreased matrix metalloproteinase activity and without significant differences in myofibroblast accumulation. In vitro, TLR4-deficient primary tubular epithelial cells and myofibroblasts produced significantly less type I collagen mRNA after TGF-beta stimulation than WT cells. The reduced fibrosis in TLR4-deficient mice associated with an upregulation of Bambi, a negative regulator of TGF-beta signaling. In conclusion, TLR4 attenuates tubular damage but promotes renal fibrosis by modulating the susceptibility of renal cells to TGF-beta. These data suggest that TLR4 signaling may be a therapeutic target for the prevention of renal fibrosis.

  4. Association of renal tubular damage with cardio-renal anemia syndrome in patients with heart failure.

    PubMed

    Otaki, Yoichiro; Watanabe, Tetsu; Takahashi, Hiroki; Narumi, Taro; Kadowaki, Shinpei; Honda, Yuki; Arimoto, Takanori; Shishido, Tetsuro; Miyamoto, Takuya; Konta, Tsuneo; Kubota, Isao

    2014-05-01

    Cardio-renal anemia syndrome (CRAS) has begun to gather attention as a vicious circle since chronic heart failure (CHF), chronic kidney disease (CKD), and anemia are all able to be caused and exacerbated by each other. However, it remains unclear whether renal tubular damage (RTD), another type of kidney dysfunction, is associated with this vicious circle. The aim of the present study was to assess the association of RTD with CRAS in patients with CHF. We included 300 consecutive patients with CHF. RTD was defined as a urinary β2-microglobulin to creatinine ratio ≥ 300 μg/g. Patients with RTD had lower serum iron and higher levels of high sensitivity C-reactive protein than those without it. Multivariate logistic analysis showed that RTD was closely associated with anemia in patients with CHF, after adjustment for confounding factors. During a median period of 1,098 days, there were 86 cardiac events, including 14 cardiac deaths and 72 re-hospitalizations for worsening heart failure. Net reclassification improvement was significantly improved by addition of RTD to the model including age, New York Heart Association functional class, brain natriuretic peptide, anemia, and CKD. All patients were divided into 3 groups: CRAS+RTD group, CRAS group, and control group. Kaplan-Meier analysis demonstrated that CRAS+RTD had the greatest risk in patients with CHF. RTD was associated with normocytic anemia, accompanying iron deficiency and inflammation. RTD added prognostic information to conventional CRAS, suggesting the importance of RTD in cardio-renal anemia interaction. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. DNA damage response in renal ischemia-reperfusion and ATP-depletion injury of renal tubular cells.

    PubMed

    Ma, Zhengwei; Wei, Qingqing; Dong, Guie; Huo, Yuqing; Dong, Zheng

    2014-07-01

    Renal ischemia-reperfusion leads to acute kidney injury (AKI) that is characterized pathologically by tubular damage and cell death, followed by tubular repair, atrophy and interstitial fibrosis. Recent work suggested the possible presence of DNA damage response (DDR) in AKI. However, the evidence is sketchy and the role and regulation of DDR in ischemic AKI remain elusive. In this study, we demonstrated the induction of phosphorylation of ATM, H2AX, Chk2 and p53 during renal ischemia-reperfusion in mice, suggesting DDR in kidney tissues. DDR was also induced in vitro during the recovery or "reperfusion" of renal proximal tubular cells (RPTCs) after ATP depletion. DDR in RPTCs was abrogated by supplying glucose to maintain ATP via glycolysis, indicating that the DDR depends on ATP depletion. The DDR was also suppressed by the general caspase inhibitor z-VAD and the overexpression of Bcl-2, supporting a role of apoptosis-associated DNA damage in the DDR. N-acetylcysteine (NAC), an antioxidant, suppressed the phosphorylation of ATM and p53 and, to a less extent, Chk2, but NAC increased the phosphorylation and nuclear foci formation of H2AX. Interestingly, NAC increased apoptosis, which may account for the observed H2AX activation. Ku55933, an ATM inhibitor, blocked ATM phosphorylation and ameliorated the phosphorylation of Chk2 and p53, but it increased H2AX phosphorylation and nuclear foci formation. Ku55933 also increased apoptosis in RPTCs following ATP depletion. The results suggest that DDR occurs during renal ischemia-reperfusion in vivo and ATP-depletion injury in vitro. The DDR is partially induced by apoptosis and oxidative stress-related DNA damage. ATM, as a sensor in the DDR, may play a cytoprotective role against tubular cell injury and death.

  6. Tubular cell apoptosis and proliferation in the early phase of renal damage in uninephrectomized SHR.

    PubMed

    Rodríguez-López, Ana M; Flores, Olga; Arévalo, Miguel A; López-Novoa, José M

    2002-01-01

    In the present study, we measured tubular cell apoptosis and proliferation and Bcl-2 expression during the early phase (3 months) of the process of renal fibrosis in the experimental model of uninephrectomized spontaneously hypertensive rats (SHR). Tubulointerstitial fibrosis was evaluated by automated quantitative morphometry using selective staining of the extracellular matrix with sirius red. Apoptosis was quantified by both in situ dUTP biotin nick end-labeling method (TUNEL) and by propidium iodide staining. Proliferation rate was measured by counting cells expressing the proliferating cell nuclear antigen. Bcl-2 expression was assessed by immunohistochemistry. Tubulointerstitial fibrosis increased progressively during the 3 months of follow-up. Proliferation and apoptosis rates in tubular cells increased from the first to the second month after UNX. In the third month after UNX, the proliferating tubular cell number continued to increase, whereas the apoptotic cell number was maintained, coinciding with an increase in the expression of Bcl-2. Our observations demonstrate a different profile of tubular cell proliferation and apoptosis during the genesis of early tubulointerstitial damage in UNX-SHR. Copyright 2002 S. Karger AG, Basel

  7. Tubular overexpression of Gremlin in transgenic mice aggravates renal damage in diabetic nephropathy.

    PubMed

    Marchant, Vanessa; Droguett, Alejandra; Valderrama, Graciela; Burgos, M Eugenia; Carpio, Daniel; Kerr, Bredford; Ruiz-Ortega, Marta; Egido, Jesús; Mezzano, Sergio

    2015-09-15

    Diabetic nephropathy (DN) is currently a leading cause of end-stage renal failure worldwide. Gremlin was identified as a gene differentially expressed in mesangial cells exposed to high glucose and in experimental diabetic kidneys. We have described that Gremlin is highly expressed in biopsies from patients with diabetic nephropathy, predominantly in areas of tubulointerstitial fibrosis. In streptozotocin (STZ)-induced experimental diabetes, Gremlin deletion using Grem1 heterozygous knockout mice or by gene silencing, ameliorates renal damage. To study the in vivo role of Gremlin in renal damage, we developed a diabetic model induced by STZ in transgenic (TG) mice expressing human Gremlin in proximal tubular epithelial cells. The albuminuria/creatinuria ratio, determined at week 20 after treatment, was significantly increased in diabetic mice but with no significant differences between transgenic (TG/STZ) and wild-type mice (WT/STZ). To assess the level of renal damage, kidney tissue was analyzed by light microscopy (periodic acid-Schiff and Masson staining), electron microscopy, and quantitative PCR. TG/STZ mice had significantly greater thickening of the glomerular basement membrane, increased mesangial matrix, and podocytopenia vs. WT/STZ. At the tubulointerstitial level, TG/STZ showed increased cell infiltration and mild interstitial fibrosis. In addition, we observed a decreased expression of podocin and overexpression of monocyte chemoattractant protein-1 and fibrotic-related markers, including transforming growth factor-β1, Col1a1, and α-smooth muscle actin. Together, these results show that TG mice overexpressing Gremlin in renal tubules develop greater glomerular and tubulointerstitial injury in response to diabetic-mediated damage and support the involvement of Gremlin in diabetic nephropathy.

  8. Proximal renal tubular acidosis

    MedlinePlus

    ... References Krapf R, Seldin DW, Alpern RJ. Clinical syndromes of metabolic acidosis. In: Alpern RJ, Caplan M, Moe OW, ... 529. Read More Distal renal tubular acidosis Fanconi syndrome Low potassium level Metabolic acidosis Osteomalacia Respiratory acidosis Rickets Review Date 10/ ...

  9. Distal renal tubular acidosis

    MedlinePlus

    ... get better with treatment. When to Contact a Medical Professional Call your health care provider if you have symptoms of distal renal tubular acidosis. Get medical help right away if you develop emergency symptoms ...

  10. Hydroxyethylstarch impairs renal function and induces interstitial proliferation, macrophage infiltration and tubular damage in an isolated renal perfusion model

    PubMed Central

    Hüter, Lars; Simon, Tim-Philipp; Weinmann, Lenard; Schuerholz, Tobias; Reinhart, Konrad; Wolf, Gunter; Amann, Kerstin Ute; Marx, Gernot

    2009-01-01

    Introduction The aim of the study was to evaluate some of the underlying pathomechanisms of hydroxyethylstarch (HES) induced adverse effects on renal function using 24 porcine kidneys in an isolated perfusion model over six hours. Methods Infusion of either 10% HES 200/0.5, 6% HES 130/0.42 or Ringer's lactate (RL) was performed to achieve an haematocrit of 20% in eight kidneys from four animals per group. Physiological and pathophysiological parameters were determined (including N-acetyl-beta-aminoglucosidase as a marker for lysosomal tubular damage). Histological investigations and immunohistological stainings of the kidneys were performed. Results Initially after haemodilution, HES 130/0.42 and HES 200/0.5 reduced urine output compared with RL (P < 0.01). After six hours, N-acetyl-beta-aminoglucosidase was significantly higher in HES 200/0.5 (81 ± 23 U/L) compared with HES 130/0.42 (38 ± 12 U/L) and RL (21 ± 13 U/L; P < 0.001). Osmotic nephrosis-like lesions (OL) of the tubuli were present in all groups showing a significantly lower number of OL in RL (1.1 ± 0.4; P = 0.002) compared with both HES groups (HES 200/0.5 = 2.1 ± 0.6; HES 130/0.42 = 2.0 ± 0.5). Macrophage infiltration was significantly higher in HES 200/0.5 compared with HES 130/0.42 (1.3 ± 1.0 vs. 0.2 ± 0.04; P = 0.044). There was a significant increase in interstitial cell proliferation in the HES 200/0.5 group vs. HES 130/0.42 (18.0 ± 6.9 vs. 6.5 ± 1.6; P = 0.006) with no significant difference in RL (13.5 ± 4.0). Conclusions We observed impaired diuresis and sodium excretion by HES and identified renal interstitial proliferation, macrophage infiltration and tubular damage as potential pathological mechanisms of HES-induced adverse effects on renal function using an isolated porcine renal perfusion model. Furthermore, we demonstrated that 10% HES 200/0.5 had more of a pro-inflammatory effect compared with 6% HES 130/0.42 and caused more pronounced tubular damage than 6% HES 130/0.42 and

  11. Renal tubular acidosis.

    PubMed

    Chan, J C

    1983-03-01

    In the past decade major advances in our understanding of renal tubular hydrogen ion secretion and bicarbonate reabsorption have provided new insight into the pathophysiology of renal tubular acidosis. Thus "fragment to fragment clings" and the number of disorders categorized within the syndrome grows, until we have come to know and name four types, with many subtypes. We hope this new perspective provides a basis for the physician to recognize renal tubular acidosis in its several forms so that an informed decision may be arrived at in choosing the best therapy. The physician may also be prepared to reasonably project the prognosis for each patient. We also hope that our detailed examination of renal acidification will provide a reference for delineation of new clinical expressions of acid-base disorders and kidney malfunction certain to be described in the years ahead.

  12. Renal tubular acidosis.

    PubMed

    Rothstein, M; Obialo, C; Hruska, K A

    1990-12-01

    Renal tubular acidosis refers to a group of disorders that result from pure tubular damage without concomitant glomerular damage. They could be hereditary (primary) or acquired (secondary to various disease states like sickle cell disease, obstructive uropathy, postrenal transplant, autoimmune disease, or drugs). The hallmark of the disorder is the presence of hyperchloremic metabolic acidosis with, or without, associated defects in potassium homeostasis, a UpH greater than 5.5 in the presence of systemic acidemia, and absence of an easily identifiable cause of the acidemia. There are three physiologic types whose basic defects are impairment of or a decrease in acid excretion, i.e., type 1 (dRTA); a failure in bicarbonate reabsorption, i.e., type 2 (pRTA); and deficiency of buffer or impaired generation of NH4+, i.e., type 4 RTA. Several pathophysiologic mechanisms have been postulated for these various types. pRTA is the least common of all in the adult population. It rarely occurs as an isolated defect. It is frequently accompanied by diffuse proximal tubule transport defects with aminoaciduria, glycosuria, hyperphosphaturia, and so forth (Fanconi syndrome). dRTA is associated with a high incidence of nephrolithiasis, nephrocalcinosis, osteodystrophy, and growth retardation (in children). Osteodystrophy also occurs in pRTA to a lesser degree and is believed to be secondary to hypophosphatemia. Patients with type 4 RTA usually have mild renal insufficiency from either diabetes mellitus or interstitial nephritis. Acute bicarbonate loading will result in a high fractional excretion of bicarbonate greater than 15% (FEHCO3- greater than 15%) in patients with pRTA, but FEHCO3- less than 3% in patients with dRTA. Type I patients will also have a low (U - B) PCO2 with bicarbonate loading. They are also unable to lower their urine pH to less than 5.5 with NH4Cl loading. The treatment of these patients involves avoidance of precipitating factors when possible, treatment

  13. [Inherited tubular renal acidosis].

    PubMed

    Bouzidi, Hassan; Hayek, Donia; Nasr, Dhekra; Daudon, Michel; Fadhel Najjar, Mohamed

    2011-01-01

    Renal tubular acidosis (RTA) is a tubulopathy characterized by metabolic acidosis with normal anion gap secondary to abnormalities of renal acidification. RTA can be classified into four main subtypes: distal RTA, proximal RTA, combined proximal and distal RTA, and hyperkalemic RTA. Distal RTA (type 1) is caused by the defect of H(+) secretion in the distal tubules and is characterized by the inability to acidify the urine below pH 5.5 during systemic acidemia. Proximal RTA (type 2) is caused by an impairment of bicarbonate reabsorption in the proximal tubules and characterized by a decreased renal bicarbonate threshold. Combined proximal and distal RTA (type 3) secondary to a reduction in tubular reclamation of bicarbonate and an inability to acidify the urine in the face of severe acidemia. Hyperkalemic RTA (type 4) may occur as a result of aldosterone deficiency or tubular insensitivity to aldosterone. Clinicians should be alert to the presence of RTA in patients with an unexplained normal anion gap acidosis, hypokalemia, recurrent nephrolithiasis and nephrocalcinosis. The mainstay of treatment of RTA remains alkali replacement.

  14. Lovastatin prevents cisplatin-induced activation of pro-apoptotic DNA damage response (DDR) of renal tubular epithelial cells.

    PubMed

    Krüger, Katharina; Ziegler, Verena; Hartmann, Christina; Henninger, Christian; Thomale, Jürgen; Schupp, Nicole; Fritz, Gerhard

    2016-02-01

    The platinating agent cisplatin (CisPt) is commonly used in the therapy of various types of solid tumors. The anticancer efficacy of CisPt largely depends on the formation of bivalent DNA intrastrand crosslinks, which stimulate mechanisms of the DNA damage response (DDR), thereby triggering checkpoint activation, gene expression and cell death. The clinically most relevant adverse effect associated with CisPt treatment is nephrotoxicity that results from damage to renal tubular epithelial cells. Here, we addressed the question whether the HMG-CoA-reductase inhibitor lovastatin affects the DDR of renal cells by employing rat renal proximal tubular epithelial (NRK-52E) cells as in vitro model. The data show that lovastatin has extensive inhibitory effects on CisPt-stimulated DDR of NRK-52E cells as reflected on the levels of phosphorylated ATM, Chk1, Chk2, p53 and Kap1. Mitigation of CisPt-induced DDR by lovastatin was independent of the formation of DNA damage as demonstrated by (i) the analysis of Pt-(GpG) intrastrand crosslink formation by Southwestern blot analyses and (ii) the generation of DNA strand breaks as analyzed on the level of nuclear γH2AX foci and employing the alkaline comet assay. Lovastatin protected NRK-52E cells from the cytotoxicity of high CisPt doses as shown by measuring cell viability, cellular impedance and flow cytometry-based analyses of cell death. Importantly, the statin also reduced the level of kidney DNA damage and apoptosis triggered by CisPt treatment of mice. The data show that the lipid-lowering drug lovastatin extensively counteracts pro-apoptotic signal mechanisms of the DDR of tubular epithelial cells following CisPt injury.

  15. [Tubular renal acidosis].

    PubMed

    Seidowsky, A; Moulonguet-Doleris, L; Hanslik, T; Yattara, H; Ayari, H; Rouveix, E; Massy, Z A; Prinseau, J

    2014-01-01

    Renal tubular acidosis (RTAs) are a group of metabolic disorders characterized by metabolic acidosis with normal plasma anion gap. There are three main forms of RTA: a proximal RTA called type II and a distal RTA (type I and IV). The RTA type II is a consequence of the inability of the proximal tubule to reabsorb bicarbonate. The distal RTA is associated with the inability to excrete the daily acid load and may be associated with hyperkalaemia (type IV) or hypokalemia (type I). The most common etiology of RTA type IV is the hypoaldosteronism. The RTAs can be complicated by nephrocalcinosis and obstructive nephrolithiasis. Alkalinization is the cornerstone of treatment.

  16. Deficiency for the Chemokine Monocyte Chemoattractant Protein-1 Aggravates Tubular Damage after Renal Ischemia/Reperfusion Injury

    PubMed Central

    Stroo, Ingrid; Claessen, Nike; Teske, Gwendoline J. D.; Butter, Loes M.; Florquin, Sandrine; Leemans, Jaklien C.

    2015-01-01

    Temporal expression of chemokines is a crucial factor in the regulation of renal ischemia/reperfusion (I/R) injury and repair. Beside their role in the migration and activation of inflammatory cells to sites of injury, chemokines are also involved in other processes such as angiogenesis, development and migration of stem cells. In the present study we investigated the role of the chemokine MCP-1 (monocyte chemoattractant protein-1 or CCL2), the main chemoattractant for monocytes, during renal I/R injury. MCP-1 expression peaks several days after inducing renal I/R injury coinciding with macrophage accumulation. However, MCP-1 deficient mice had a significant decreased survival and increased renal damage within the first two days, i.e. the acute inflammatory response, after renal I/R injury with no evidence of altered macrophage accumulation. Kidneys and primary tubular epithelial cells from MCP-1 deficient mice showed increased apoptosis after ischemia. Taken together, MCP-1 protects the kidney during the acute inflammatory response following renal I/R injury. PMID:25875776

  17. Deficiency for the chemokine monocyte chemoattractant protein-1 aggravates tubular damage after renal ischemia/reperfusion injury.

    PubMed

    Stroo, Ingrid; Claessen, Nike; Teske, Gwendoline J D; Butter, Loes M; Florquin, Sandrine; Leemans, Jaklien C

    2015-01-01

    Temporal expression of chemokines is a crucial factor in the regulation of renal ischemia/reperfusion (I/R) injury and repair. Beside their role in the migration and activation of inflammatory cells to sites of injury, chemokines are also involved in other processes such as angiogenesis, development and migration of stem cells. In the present study we investigated the role of the chemokine MCP-1 (monocyte chemoattractant protein-1 or CCL2), the main chemoattractant for monocytes, during renal I/R injury. MCP-1 expression peaks several days after inducing renal I/R injury coinciding with macrophage accumulation. However, MCP-1 deficient mice had a significant decreased survival and increased renal damage within the first two days, i.e. the acute inflammatory response, after renal I/R injury with no evidence of altered macrophage accumulation. Kidneys and primary tubular epithelial cells from MCP-1 deficient mice showed increased apoptosis after ischemia. Taken together, MCP-1 protects the kidney during the acute inflammatory response following renal I/R injury.

  18. Oral erdosteine administration attenuates cisplatin-induced renal tubular damage in rats.

    PubMed

    Yildirim, Zeki; Sogut, Sadik; Odaci, Ersan; Iraz, Mustafa; Ozyurt, Huseyin; Kotuk, Mahir; Akyol, Omer

    2003-02-01

    The effect of oral erdosteine on tissue malondialdehyde (MDA) and nitric oxide (NO) levels, and catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities are investigated in the cisplatin model of acute renal failure in rats. A single dose of cisplatin caused kidney damage manifested by kidney histology as well as increases in plasma creatinine and blood urea nitrogen (BUN) levels. Treatment with free radical scavenger erdosteine attenuated increases in plasma creatinine and BUN, and tissue MDA and NO levels, and provided a histologically-proven protection against cisplatin-induced acute renal failure. Erdosteine also reduced depletion in the tissue CAT, GSH-Px, and SOD activities. These results show that erdosteine may be a promising drug for protection against cisplatin-induced nephrotoxicity. However, further studies with different doses of erdosteine are warranted for clarifying the issue.

  19. Renal tubular function in hyperparathyroidism.

    PubMed Central

    van 't Hoff, W.; Bicknell, E. J.

    1989-01-01

    Renal tubular function was assessed in a group of patients with mild hyperparathyroidism before and after a mean period of 2.7 years conservative management. It was also assessed, before and after a mean of 3.3 years following surgery in a group of patients with initially higher plasma calcium concentration. Mean maximum urine osmolality was within the accepted range as was the maximum urine plasma hydrogen ion gradient in both groups at the time of diagnosis. No significant change in renal tubular function was observed in either group over the periods of this study. Although deterioration after a long period cannot be excluded, we do not consider that regular assessment of renal tubular function is necessary in the conservative management of primary hyperparathyroidism. PMID:2616415

  20. Dahuang Fuzi Decoction ameliorates tubular epithelial apoptosis and renal damage via inhibiting TGF-β1-JNK signaling pathway activation in vivo.

    PubMed

    Tu, Yue; Sun, Wei; Wan, Yi-Gang; Gao, Kun; Liu, Hong; Yu, Bing-Yin; Hu, Hao; Huang, Yan-Ru

    2014-10-28

    Dahuang Fuzi Decoction (DFD) is a traditional well-prescribed formula for the treatment of chronic kidney disease (CKD) in China. This study was carried out to examine the effects of DFD in adenine-induced tubular epithelial apoptosis and renal damage, in comparison with allopurinol (AP), then to clarify the therapeutic mechanisms in vivo. A rat model of renal damage was created by adenine. Rats in Normal and Vehicle groups received distilled water, while rats in DFD and AP groups received DFD and AP, respectively. Proteinuria; urinary N-acetyl-β-D-glucosaminidase (NAG) levels; the blood biochemical parameters; renal histopathology damage; transferase-mediated dUTP nick-end labeling (TUNEL)-staining; the key molecular protein expressions in mitochondrial and transforming growth factor (TGF)-β1-c-JunNH2-terminal kinase (JNK) pathways were examined, respectively. Adenine administration induced severe renal damages, as indicated by the mass proteinuria, the heavy urinary NAG, and the marked histopathological injury in tubules and interstitium. This was associated with the activation of TGF-β1-JNK signaling pathway and tubular epithelial apoptosis. DFD treatment, however, significantly prevented proteinuria and urinary NAG elevation, and attenuated tubular epithelial apoptosis. It suppressed the protein expressions of Bax and cleaved caspase-3, whereas it enhanced the protein expression of Bcl-2. Furthermore, it also suppressed the protein levels of TGF-β1 as well as phosphorylated-JNK (p-JNK). DFD alleviated adenine-induced tubular epithelial apoptosis and renal damage in vivo, presumably through the suppression of TGF-β1-JNK pathway activation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Resveratrol ameliorates hyperglycemia-induced renal tubular oxidative stress damage via modulating the SIRT1/FOXO3a pathway.

    PubMed

    Wang, Xueling; Meng, Linghang; Zhao, Long; Wang, Zengfu; Liu, Haiying; Liu, Gang; Guan, Guangju

    2017-04-01

    Oxidative stress plays an important role in the development and progression of diabetic nephropathy (DN). We aimed to investigate if resveratrol (RSV) could ameliorate hyperglycemia-induced oxidative stress in renal tubules via modulating the SIRT1/FOXO3a pathway. The effects of RSV on diabetes rats were assessed by periodic acid-Schiff, Masson staining, immunohistochemistry, and western blot analyses. Additionally, oxidative indicators (such as catalase, superoxide dismutase, reactive oxygen species, and malondialdehyde), the deacetylase activity of SIRT1 and protein expressions of SIRT1, FOXO3a, and acetylated-FOXO3a were measured. These indicators were similarly evaluated in an in vitro study. Furthermore, the silencing of SIRT1 was used to confirm its role in the resistance to oxidative stress and the relationship between SIRT1 and FOXO3a in vitro. After 16weeks of RSV treatment, the renal function and glomerulosclerosis of rats with DN was dramatically ameliorated. RSV treatment increased SIRT1 deacetylase activity, subsequently decreasing the expression of acetylated-FOXO3a and inhibiting the oxidative stress caused by hyperglycemia both in vivo and in vitro. The silencing of SIRT1 in HK-2 cells aggravated the high glucose-induced oxidative stress and overexpression of acetylated-FOXO3a; RSV treatment failed to protect against these effects. RSV modulates the SIRT1/FOXO3a pathway by increasing SIRT1 deacetylase activity, subsequently ameliorating hyperglycemia-induced renal tubular oxidative stress damage. This mechanism provides the basis for a new approach to developing an effective DN treatment, which is of great clinical significance for reducing the morbidity and mortality associated with DN. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Angiotensin II receptor blocker inhibits tumour necrosis factor-alpha-induced cell damage in human renal proximal tubular epithelial cells.

    PubMed

    Kagawa, Toru; Takao, Toshihiro; Horino, Taro; Matsumoto, Reiko; Inoue, Kousuke; Morita, Tatsuhito; Hashimoto, Kozo

    2008-06-01

    We investigated the effect of angiotensin II (AII) type 1 (AT1) and angiotensin II type 2 (AT2) receptor blockers on tumour necrosis factor alpha (TNF-alpha)-induced cell damage in human renal proximal tubular epithelial cells (RPTEC). The lactate dehydrogenase (LDH) and N-acetyl-beta-glucosaminidase (NAG) release into the medium after TNF-alpha treatment in RPTEC were determined using modified commercial procedures. In addition, the levels of caspase 3/7 activity in RPTEC were measured after TNF-alpha treatment with AlphaTau1 or AT2 receptor blockers. Finally we investigated the change of p22phox protein levels after TNF-alpha with AlphaTau1 or AT2 receptor blockers in RPTEC. Tumour necrosis factor alpha (10(-8) mol/L) significantly increased LDH and NAG release into the medium from RPTEC. AlphaTau1 receptor blockers, olmesartan and valsartan (10(-9)-10(-6) mol/L) showed a significant reduction on TNF-alpha-induced LDH and NAG release in RPTEC. AT2 receptor blocker, PD123319 (10(-7)-10(-5) mol/L) also decreased TNF-alpha-induced LDH and NAG release in RPTEC. Blockade of both AlphaTau1 and AT2 receptor indicated additional reduction on TNF-alpha-induced LDH and NAG release. TNF-alpha (10(-8) mol/L) treatment showed small but significant increases of caspase 3/7 activity in RPTEC, and AT1 and AT2 receptor blockers (10(-8) mol/L) comparably decreased TNF-alpha-induced caspase 3/7 activity. Significant increases of p22phox protein levels were observed in TNF-alpha-treated group in RPTEC. However, only AlphaTau1 (10(-8) mol/L) but not AT2 (10(-5) mol/L) receptor blocker significantly decreased TNF-alpha-induced p22phox protein levels. The present study demonstrates that TNF-alpha induces renal tubular cell damage in RPTEC and AT1/AT2 receptor blockers showed cytoprotective effects probably via at least partly different mechanism.

  3. Possible roles of tumor necrosis factor-α and angiotensin II type 1 receptor on high glucose-induced damage in renal proximal tubular cells.

    PubMed

    Takao, Toshihiro; Horino, Taro; Matsumoto, Reiko; Shimamura, Yoshiko; Ogata, Koji; Inoue, Kousuke; Taniguchi, Yoshinori; Taguchi, Takafumi; Terada, Yoshio

    2015-02-01

    Recent studies have identified that high glucose-induced renal tubular cell damage. We previously demonstrated that high glucose treatment induced oxidative stress in human renal proximal tubular epithelial cells (RPTECs), and angiotensin II type 1 (AT1) receptor blockers reduce high glucose-induced oxidative stress in RPTEC possibly via blockade of intracellular as well as extracellular AT1 receptor. However, exact roles of tumor necrosis factor (TNF)-α and AT1 receptor on high glucose-induced renal tubular function remain unclear. N-acetyl-beta-glucosaminidase (NAG), concentrations of TNF-α/angiotensin II and p22(phox) protein levels after high glucose treatment with or without AT1 receptor blocker or thalidomide, an inhibitor of TNF-α protein synthesis, were measured in immortalized human renal proximal tubular epithelial cells (HK2 cells). AT1 receptor knockdown was performed with AT1 receptor small interfering RNA (siRNA). High glucose treatment (30 mM) significantly increased NAG release, TNF-α/angiotensin II concentrations in cell media and p22(phox) protein levels compared with those in regular glucose medium (5.6 mM). Candesartan, an AT1R blocker, showed a significant reduction on high glucose-induced NAG release, TNF-α concentrations and p22(phox) protein levels in HK2 cells. In addition, significant decreases of NAG release, TNF-α concentrations and p22(phox) protein levels in HK2 cells were observed in high glucose-treated group with thalidomide. AT1R knockdown with siRNA markedly reversed high glucose, angiotensin II or TNF-α-induced p22(phox) protein levels in HK2 cells. TNF-α may be involved in high glucose-induced renal tubular damage in HK2 cells possibly via AT1 receptor signaling.

  4. Pharmacogenetics may Influence Tacrolimus Daily Dose, but not Urinary Tubular Damage Markers in the Long-Term Period after Renal Transplantation

    PubMed Central

    Stefanović, Nikola Z.; Cvetković, Tatjana P.; Veličković-Radovanović, Radmila M.; Jevtović-Stoimenov, Tatjana M.; Vlahović, Predrag M.; Stojanović, Ivana R.; Pavlović, Dušica D.

    2015-01-01

    Summary Background The primary goal of this study was to evaluate the influence of cytochrome P450 (CYP) 3A5 (6986A>G) and ABCB1 (3435C>T) polymorphisms on tacrolimus (TAC) dosage regimen and exposure. Second, we evaluated the influence of TAC dosage regimen and the tested polymorphisms on renal oxidative injury, as well as the urinary activities of tubular ectoenzymes in a long-term period after transplantation. Also, we aimed to determine the association between renal oxidative stress and tubular damage markers in the renal transplant patients. Methods The study included 72 patients who were on TAC based immunosuppression. Allele-specific PCR was used for polymorphism determination. We measured the urinary thiobarbituric acid reactive substances (TBARS) and reactive carbonyl derivates (RCD) in order to evaluate oxidative injury, as well as the urinary activities of ectoenzymes (N-acetyl-β-D-glucosaminidase, aminopeptidase N and dipeptidyl peptidase IV) to evaluate tubular damage. Results The carriers of CYP 3A5*1 allele required statistically higher daily doses of TAC than CYP *3/*3 carriers, as well as the carriers of C allele of ABCB1 gene compared to those with TT genotype. Also, there were no differences in TBARS, RCD and the activities of ectoenzymes between the patients’ genotypes. Our results showed significant correlations between urinary TBARS and RCD and the ectoenzymes’ activities. Conclusions Our findings suggest that CYP 3A5 and ABCB1 3435 polymorphism may affect TAC daily doses, but not the drug’s tubular toxicity. Furthermore, tubular damage may be associated with increased renal oxidative stress. PMID:28356851

  5. Renal tubular secretion of pramipexole.

    PubMed

    Knop, Jana; Hoier, Eva; Ebner, Thomas; Fromm, Martin F; Müller, Fabian

    2015-11-15

    The dopamine agonist pramipexole is cleared predominantly by the kidney with a major contribution of active renal secretion. Previously the organic cation transporter 2 (OCT2) was shown to be involved in the uptake of pramipexole by renal tubular cells, while the mechanism underlying efflux into tubular lumen remains unclear. Cimetidine, a potent inhibitor of multidrug and toxin extrusion proteins 1 (MATE1) and 2-K (MATE2-K), decreases renal pramipexole clearance in humans. We hypothesized that, in addition to OCT2, pramipexole may be a substrate of MATE-mediated transport. Pramipexole uptake was investigated using MDCK or HEK cells overexpressing OCT2, MATE1 or MATE2-K and the respective vector controls (Co). Transcellular pramipexole transport was investigated in MDCK cells single- or double-transfected with OCT2 and/or MATE1 and in Co cells, separating a basal from an apical compartment in a model for renal tubular secretion. Pramipexole uptake was 1.6-, 1.1-, or 1.6-folds in cells overexpressing OCT2, MATE1 or MATE2-K, respectively as compared to Co cells (p<0.05). In transcellular transport experiments, intracellular pramipexole accumulation was 1.7-folds in MDCK-OCT2 (p<0.001), and transcellular pramipexole transport was 2.2- and 4.0-folds in MDCK-MATE1 and MDCK-OCT2-MATE1 cells as compared to Co cells (p<0.001). Transcellular pramipexole transport was pH dependent and inhibited by cimetidine with IC50 values of 12μM and 5.5μM in MATE1 and OCT2-MATE1 cells, respectively. Taken together, coordinate activity of OCT2-mediated uptake and MATE-mediated efflux determines pramipexole renal secretion. Reduced OCT2 or MATE transport activity due to genetic variation or drug-drug interactions may affect pramipexole renal secretion. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Renal tubular acidosis type 4 in pregnancy.

    PubMed

    Jakes, Adam Daniel; Baynes, Kevin; Nelson-Piercy, Catherine

    2016-03-17

    We describe the clinical course of renal tubular acidosis (RTA) type 4 in pregnancy, which has not been previously published. Renal tubular acidosis type 4 is a condition associated with increased urinary ammonia secondary to hypoaldosteronism or pseudohypoaldosteronism. Pregnancy may worsen the hyperkalaemia and acidosis of renal tubular acidosis type 4, possibly through an antialdosterone effect. We advise regular monitoring of potassium and pH throughout pregnancy to ensure safe levels are maintained.

  7. Hyperammonaemia with distal renal tubular acidosis.

    PubMed

    Miller, S G; Schwartz, G J

    1997-11-01

    The case is reported of an infant with hyperammonaemia secondary to severe distal renal tubular acidosis. A clinical association between increased concentrations of ammonia in serum and renal tubular acidosis has not previously been described. In response to acidosis the infant's kidneys presumably increased ammonia synthesis but did not excrete ammonia, resulting in hyperammonaemia. The patient showed poor feeding, frequent vomiting, and failure to thrive, but did not have an inborn error of metabolism. This case report should alert doctors to consider renal tubular acidosis in the differential diagnosis of severely ill infants with metabolic acidosis and hyperammonaemia.

  8. Human renal tubular cells contain CD24/CD133 progenitor cell populations: Implications for tubular regeneration after toxicant induced damage using cadmium as a model.

    PubMed

    Shrestha, Swojani; Somji, Seema; Sens, Donald A; Slusser-Nore, Andrea; Patel, Divyen H; Savage, Evan; Garrett, Scott H

    2017-09-15

    The proximal tubules of the kidney are target sites of injury by various toxicants. Cadmium (Cd(+2)), an environmental nephrotoxicant can cause adverse effects and overt renal damage. To decipher the mechanisms involved in nephrotoxicity, an in vitro model system is required. Mortal cultures of human proximal tubule (HPT) cells have served, as models but are difficult to acquire and do not lend themselves to stable transfection. The immortalized human proximal tubule cell line HK-2, has served as a model but it lacks vectorial active transport and shows signs of lost epithelial features. Recently a new proximal tubule cell line was developed, the RPTEC/TERT1, and the goal of this study was to determine if this cell line could serve as a model to study nephrotoxicity. Global gene expression analysis of this cell line in comparison to the HK-2 and HPT cells showed that the RPTEC/TERT1 cells had gene expression patterns similar to HPT cells when compared to the HK-2 cells. The HPT and the RPTEC/TERT1 cell line had an increased population of stem/progenitor cells co-expressing CD24 and CD133 when compared to the HK-2 cells. The level of expression of cadherins, claudins and occludin molecules was also similar between the RPTEC/TERT1 and the HPT cells. Acute exposure to Cd(+2) resulted in necrosis of the RPTEC/TERT1 cells when compared to the HK-2 cells which died by apoptosis. Thus, the RPTEC/TERT1 cells are similar to HPT cells and can serve as a good model system to study mechanisms involved in toxicant induced renal damage. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. AKI in early sepsis is a continuum from transient AKI without tubular damage over transient AKI with minor tubular damage to intrinsic AKI with severe tubular damage.

    PubMed

    Vanmassenhove, J; Glorieux, G; Hoste, E; Dhondt, A; Vanholder, R; Van Biesen, W

    2014-10-01

    The pathophysiology of septic acute kidney injury (AKI) is incompletely understood, and there is controversy on the role of renal hypoperfusion in early sepsis. We hypothesized that renal hypoperfusion plays a role in early sepsis and that there is a continuum between transient AKI without tubular damage, transient AKI with minor tubular damage, and intrinsic AKI. A total of 107 consecutive patients with sepsis were included. Fractional excretion of sodium (FENa), urinary, and serum neutrophil gelatinase-associated lipocalin were measured at admission (T0) and 4 h (T4) and 24 h later (T24). Patients were classified according to FENa quartiles (FENaQ). Transient and intrinsic AKI were respectively defined as AKI that did or did not recover to no AKI in the following 5 days. A total of 57 developed transient AKI, 22 developed intrinsic AKI, and 28 did not have AKI. Of the ten patients with transient AKI classified in the two lowest FENa quartiles (FENa < 0.36 %) and without signs of local tubular damage, seven still did not show signs of tubular damage 24 h later. Also, 50 % of patients with intrinsic AKI classified in the same FENaQ did not show signs of local tubular damage at admission but did so 24 h later. There is a continuum between transient AKI without tubular damage, transient AKI with minor tubular damage, and intrinsic AKI in sepsis. Renal hypoperfusion seems to be the instigator for the development of AKI in the majority of patients with early sepsis. Other mechanisms in some patients cannot be excluded.

  10. Renal Primary Cilia Lengthen after Acute Tubular Necrosis

    PubMed Central

    Verghese, Elizabeth; Ricardo, Sharon D.; Weidenfeld, Raphael; Zhuang, Junli; Hill, Prudence A.; Langham, Robyn G.

    2009-01-01

    Renal primary cilia are sensory antennas required for the maintenance of normal epithelial differentiation and proliferation in the kidney, but they also have a potential role in epithelial differentiation during renal injury and repair. In mice, tubular damage causes an increase in the length of renal cilia, which may modify their sensory sensitivity during repair. Here, we investigated whether the alteration of renal cilium length during renal injury is clinically relevant. Using biopsies of human renal transplants that suffered acute tubular necrosis during transplantation, we compared the length of renal primary cilia with renal function. Serial biopsies showed that acute tubular necrosis resulted in more than a doubling of cilium length throughout the nephron and collecting duct approximately 1 wk after injury. Allografts displayed a trend toward normalization of cilium length in later biopsies, and this correlated with functional recovery. A mouse model of renal ischemia-reperfusion confirmed the increase and subsequent regression of cilium length during renal repair, displaying complete normalization of cilium length within 6 wk of injury. These findings demonstrate that the length of renal cilia is a clinically relevant indicator of renal injury and repair. PMID:19608704

  11. Effects of angiotensin II type 1 receptor blocker on albumin-induced cell damage in human renal proximal tubular epithelial cells.

    PubMed

    Takao, Toshihiro; Horino, Taro; Kagawa, Toru; Matsumoto, Reiko; Inoue, Kousuke; Taguchi, Takafumi; Morita, Tatsuhito; Iwasaki, Yasumasa; Hashimoto, Kozo; Terada, Yoshio

    2009-01-01

    Proteinuria is not merely a marker of chronic nephropathies, but may also be involved in the progression to end-stage renal failure. We investigated the effect of angiotensin II type 1 receptor blockers (ARBs) on albumin-induced cell damage in human renal proximal tubular epithelial cells (RPTEC). The N-acetyl-beta-D-glucosaminidase (NAG) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in the medium after albumin treatment with ARBs were determined by commercially available kits. The levels of p22(phox) protein in RPTEC were measured using Western blotting after albumin treatment with ARBs. Angiotensin II concentrations in cell media and cell lysates were assayed with a commercially available kit. Human albumin (0.1-10 mg/ml) dose-dependently increased NAG release and olmesartan or valsartan (10(-9)-10(-7) mol/l) showed a significant reduction on albumin (1 mg/ml)-induced NAG release in RPTEC. Albumin treatment (1 mg/ml) showed significant increases in p22(phox) protein levels in RPTEC and ARBs significantly decreased albumin-induced p22(phox) protein levels. Significant increases in 8-OHdG levels were observed in the albumin (1 mg/ml)-treated group and ARBs markedly reduced albumin-induced 8-OHdG levels in RPTEC. Human albumin dose-dependently increased angiotensin II concentrations in both cell media and lysates. These observations suggest renal tubular cell-protective properties of ARBs related to decreased oxidative stress during proteinuria. Copyright (c) 2008 S. Karger AG, Basel.

  12. Sex Differences in Renal Proximal Tubular Cell Homeostasis.

    PubMed

    Seppi, Thomas; Prajczer, Sinikka; Dörler, Maria-Magdalena; Eiter, Oliver; Hekl, Daniel; Nevinny-Stickel, Meinhard; Skvortsova, Iraida; Gstraunthaler, Gerhard; Lukas, Peter; Lechner, Judith

    2016-10-01

    Studies in human patients and animals have revealed sex-specific differences in susceptibility to renal diseases. Because actions of female sex hormones on normal renal tissue might protect against damage, we searched for potential influences of the female hormone cycle on basic renal functions by studying excretion of urinary marker proteins in healthy human probands. We collected second morning spot urine samples of unmedicated naturally ovulating women, postmenopausal women, and men daily and determined urinary excretion of the renal tubular enzymes fructose-1,6-bisphosphatase and glutathione-S-transferase-α Additionally, we quantified urinary excretion of blood plasma proteins α1-microglobulin, albumin, and IgG. Naturally cycling women showed prominent peaks in the temporal pattern of urinary fructose-1,6-bisphosphatase and glutathione-S-transferase-α release exclusively within 7 days after ovulation or onset of menses. In contrast, postmenopausal women and men showed consistently low levels of urinary fructose-1,6-bisphosphatase excretion over comparable periods. We did not detect changes in urinary α1-microglobulin, albumin, or IgG excretion. Results of this study indicate that proximal tubular tissue architecture, representing a nonreproductive organ-derived epithelium, undergoes periodical adaptations phased by the female reproductive hormone cycle. The temporally delimited higher rate of enzymuria in ovulating women might be a sign of recurring increases of tubular cell turnover that potentially provide enhanced repair capacity and thus, higher resistance to renal damage.

  13. Distal Renal Tubular Acidosis and Calcium Nephrolithiasis

    NASA Astrophysics Data System (ADS)

    Moe, Orson W.; Fuster, Daniel G.; Xie, Xiao-Song

    2008-09-01

    Calcium stones are commonly encountered in patients with congenital distal renal tubular acidosis, a disease of renal acidification caused by mutations in either the vacuolar H+-ATPase (B1 or a4 subunit), anion exchanger-1, or carbonic anhydrase II. Based on the existing database, we present two hypotheses. First, heterozygotes with mutations in B1 subunit of H+-ATPase are not normal but may harbor biochemical abnormalities such as renal acidification defects, hypercalciuria, and hypocitraturia which can predispose them to kidney stone formation. Second, we propose at least two mechanisms by which mutant B1 subunit can impair H+-ATPase: defective pump assembly and defective pump activity.

  14. Mechanisms of renal tubular defects in old age.

    PubMed Central

    Dontas, A. S.; Marketos, S. G.; Papanayiotou, P.

    1972-01-01

    The mechanisms of renal tubular dysfunction in old age have been examined in twenty-eight clinically healthy elderly subjects without infection, and in fourteen subjects of similar age with laboratory evidence of intrarenal infection. The data were compared with those from thirteen clinically healthy young subjects. Studied were: proximal tubular (Tm(PAH)) and distal tubular (CH2O) activity, minimal and maximal osmolal U/P ratios, maximal osmolal excretion in hydropenia, and GFR levels under standard hydration and under water-loading. The reduction of GFR in old age is evident particularly in men under conditions of standard hydration: it is accentuated in the presence of renal infection. Proximal tubular activity is also significantly lower in elderly men, especially if they have chronic bacteriuria. The reduction is closely related to GFR levels, with identical Tm(PAH):C(in) ratios in all groups. This supports the intact nephron hypothesis for this part of the nephron. Distal tubular activity is depressed in old age in both sexes proportionately more than proximal tubular activity or the GFR. The lower CH2O: GFR ratios imply a selective distal tubular damage. Maximal osmolal U/P ratios in hydropenia are significantly higher in the young (mean 367) than in either the elderly non-infected (mean 279) or the elderly infected subjects (mean 212). Conversely, minimal U/P ratios in water-loading are lower in the young (mean 0.247) than in either elderly group (means 0.418 and 0.668). Osmolal excretion in hydropenia is not different between the groups, but urine flows in water-loading clearly separate them. The data indicate that simple functions of the distal-collecting tubule (e.g. the CH2O), are less affected in old age than are functions involving several medullary structures (as is the maximal U(osm) or U/P ratio). They suggest that the main impairment of the distal tubular cell involves the failure to achieve a proper osmotic gradient between tubular fluid and

  15. Renal tubular acidosis: an immunopathological study on four patients

    PubMed Central

    Pasternack, A.; Linder, E.

    1970-01-01

    Renal biopsies and sera of four patients with distal renal tubular acidosis were examined. The findings consisted of immunoglobulin containing mononuclear cellular infiltrates around the distal tubules, bound immunoglobulin and complement in tubules. The sera of the patients contained antibodies reacting with various tissue antigens, among them renal tubular antigens. The results suggest that autoimmunity was involved in the pathogenesis of the renal tubular acidosis in these patients. ImagesFig. 1Fig. 2 PMID:5202740

  16. Mechanisms in hyperkalemic renal tubular acidosis.

    PubMed

    Karet, Fiona E

    2009-02-01

    The form of renal tubular acidosis associated with hyperkalemia is usually attributable to real or apparent hypoaldosteronism. It is therefore a common feature in diabetes and a number of other conditions associated with underproduction of renin or aldosterone. In addition, the close relationship between potassium levels and ammonia production dictates that hyperkalemia per se can lead to acidosis. Here I describe the modern relationship between molecular function of the distal portion of the nephron, pathways of ammoniagenesis, and hyperkalemia.

  17. Distal renal tubular acidosis with hereditary spherocytosis.

    PubMed

    Sinha, Rajiv; Agarwal, Indira; Bawazir, Waleed M; Bruce, Lesley J

    2013-07-01

    Hereditary spherocytosis (HS) and distal renal tubular acidosis (dRTA), although distinct entities, share the same protein i.e. the anion exchanger1 (AE1) protein. Despite this, their coexistence has been rarely reported. We hereby describe the largest family to date with co-existence of dRTA and HS and discuss the molecular basis for the co-inheritance of these conditions.

  18. Rap1 Ameliorates Renal Tubular Injury in Diabetic Nephropathy

    PubMed Central

    Xiao, Li; Zhu, Xuejing; Yang, Shikun; Liu, Fuyou; Zhou, Zhiguang; Zhan, Ming; Xie, Ping; Zhang, Dongshan; Li, Jun; Song, Panai; Kanwar, Yashpal S.; Sun, Lin

    2014-01-01

    Rap1b ameliorates high glucose (HG)-induced mitochondrial dysfunction in tubular cells. However, its role and precise mechanism in diabetic nephropathy (DN) in vivo remain unclear. We hypothesize that Rap1 plays a protective role in tubular damage of DN by modulating primarily the mitochondria-derived oxidative stress. The role and precise mechanisms of Rap1b on mitochondrial dysfunction and of tubular cells in DN were examined in rats with streptozotocin (STZ)-induced diabetes that have Rap1b gene transfer using an ultrasound microbubble-mediated technique as well as in renal proximal epithelial tubular cell line (HK-2) exposed to HG ambiance. The results showed that Rap1b expression decreased significantly in tubules of renal biopsies from patients with DN. Overexpression of a constitutively active Rap1b G12V notably ameliorated renal tubular mitochondrial dysfunction, oxidative stress, and apoptosis in the kidneys of STZ-induced rats, which was accompanied with increased expression of transcription factor C/EBP-β and PGC-1α. Furthermore, Rap1b G12V also decreased phosphorylation of Drp-1, a key mitochondrial fission protein, while boosting the expression of genes related to mitochondrial biogenesis and antioxidants in HK-2 cells induced by HG. These effects were imitated by transfection with C/EBP-β or PGC-1α short interfering RNA. In addition, Rap1b could modulate C/EBP-β binding to the endogenous PGC-1α promoter and the interaction between PGC-1α and catalase or mitochondrial superoxide dismutase, indicating that Rap1b ameliorates tubular injury and slows the progression of DN by modulation of mitochondrial dysfunction via C/EBP-β–PGC-1α signaling. PMID:24353183

  19. [Effect of the chelator BPCBG on the decorporation of uranium in vivo and uranium-induced damage of human renal tubular epithelial cells in vitro].

    PubMed

    Bao, Yi-zhong; Wang, Dan; Hu, Yu-xing; Xu, Ai-hong; Sun, Mei-zhen; Chen, Hong-hong

    2011-11-01

    This study is to assess the efficacy of BPCBG on the decorporation of uranium (VI) and protecting human renal proximal tubular epithelial cells (HK-2) against uranium-induced damage. BPCBG at different doses was injected intramuscularly to male SD rats immediately after a single intraperitoneal injection of UO2(CH3COO)2. Twenty-four hours later uranium contents in urine, kidneys and femurs were measured by ICP-MS. After HK-2 cells were exposed to UO2(CH3COO)2 immediately or for 24 h followed by BPCBG treatment at different doses for another 24 or 48 h, the uranium contents in HK-2 cells were measured by ICP-MS, the cell survival was assayed by cell counting kit-8 assay, formation of micronuclei was determined by the cytokinesis-block (CB) micronucleus assay and the production of intracellular reactive oxygen species (ROS) was detected by 2',7'-dichlorofluorescin diacetate (DCFH-DA) oxidation. DTPA-CaNa3 was used as control. It was found that BPCBG at dosages of 60, 120, and 600 micromol kg(-1) resulted in 37%-61% increase in 24 h-urinary uranium excretion, and significantly decreased the amount of uranium retention in kidney and bone to 41%-31% and 86%-42% of uranium-treated group, respectively. After HK-2 cells that had been pre-treated with UO2(CH3COO)2 for 24 h were treated with the chelators for another 24 h, 55%-60% of the intracellular uranium was removed by 10-250 micromol L(-1) of BPCBG. Treatment of uranium-treated HK-2 cells with BPCBG significantly enhanced the cell survival, decreased the formation of micronuclei and inhibited the production of intracellular ROS. Although DTPA-CaNa3 markedly reduced the uranium retention in kidney of rats and HK-2 cells, its efficacy of uranium removal from body was significantly lower than that of BPCBG and it could not protect uranium-induced cell damage. It can be concluded that BPCBG effectively decorporated the uranium from UO2(CH3COO)2-treated rats and HK-2 cells, which was better than DTPA-CaNa3. It could also

  20. Acquired resistance to rechallenge injury in rats recovered from subclinical renal damage with uranyl acetate-Importance of proliferative activity of tubular cells

    SciTech Connect

    Sun, Yuan; Fujigaki, Yoshihide; Sakakima, Masanori; Hishida, Akira

    2010-02-15

    Animals recovered from acute renal failure are resistant to subsequent insult. We investigated whether rats recovered from mild proximal tubule (PT) injury without renal dysfunction (subclinical renal damage) acquire the same resistance. Rats 14 days after recovering from subclinical renal damage, which was induced by 0.2 mg/kg of uranyl acetate (UA) (sub-toxic dose), were rechallenged with 4 mg/kg of UA (nephrotoxic dose). Fate of PT cells and renal function were examined in response to nephrotoxic dose of UA. All divided cells after sub-toxic dose of UA insult were labeled with bromodeoxyuridine (BrdU) for 14 days then the number of PT cells with or without BrdU-labeling was counted following nephrotoxic dose of UA insult. Rats recovered from subclinical renal damage gained resistance to nephrotoxic dose of UA with reduced renal dysfunction, less severity of peak damage (necrotic and TUNEL+ apoptotic cells) and accelerated PT cell proliferation, but with earlier peak of PT damage. The decrease in number of PT cells in the early phase of rechallenge injury with nephrotoxic UA was more in rats pretreated with sub-toxic dose of UA than vehicle pretreated rats. The exaggerated loss of PT cells was mainly caused by the exaggerated loss of BrdU+ divided cells. In contrast, accelerated cell proliferation in rats recovered from sub-toxic dose of UA was observed mainly in BrdU- non-divided cells. The findings suggest that rats recovered from subclinical renal damage showed partial acquired resistance to nephrotoxic insult. Accelerated recovery with increased proliferative activity of non-divided PT cells after subclinical renal damage may mainly contribute to acquired resistance.

  1. Renal tubular function in children with beta-thalassemia minor.

    PubMed

    Kalman, Süleyman; Atay, A Avni; Sakallioglu, Onur; Ozgürtaş, Taner; Gök, Faysal; Kurt, Ismail; Kürekçi, A Emin; Ozcan, Okan; Gökçay, Erdal

    2005-10-01

    beta-thalassemia minor is a common heterozygous haemoglobinopathy that is characterized by both microcytosis and hypochromia. It requires no treatment. It has been postulated that low-grade haemolysis, tubular iron deposition and toxins derived from erythrocytes might cause renal tubular damage in adult patients with beta-thalassemia minor. Our aim was to investigate the renal tubular functions in children with beta-thalassemia minor and to determine its possible harmful effects. The study was conducted on 32 children (14 female and 18 male) at the age of 5.8 +/- 3.1 years (range 2-14 years) with beta-thalassemia minor. The patients were classified as anaemic (haemoglobin (Hb) 11 g/dL) (Group 2, n = 18). A control group was formed with 18 healthy children whose ages and sexes match those in other groups (Group 3, n = 18). Fractional excretion of sodium (FE(Na), %), fractional excretion of magnesium (FE(Mg), %), fractional excretion of uric acid (FE(UA), %) and tubular phosphorus reabsorption (TPR,%) were calculated with standard formulas. Urinary calcium excretion (mg/kg per 24 h), zinc (Zn) (microg/dL), glucosuria (mg/dL), beta-2 microglobulin (mg/dL) and N-acetyl-beta-D-glycosaminidase (NAG, U/mmol creatinine) levels were measured through biochemical methods. There was no statistically significant difference among the three groups in terms of the results of FE(Na) (%), FE(Mg) (%), FE(UA) (%), TPR (%), calciuria (mg/kg per 24 h), NAG, urine Zn, proteinuria, glucosuria or urine beta- 2 microglobulin levels (P > 0.05). On the contrary of children with beta-thalassemia major, renal tubular dysfunction has not been determined in children with beta-thalassemia minor in the present study.

  2. Renal tubular acidosis in chronic liver disease

    PubMed Central

    Golding, Peter L.

    1975-01-01

    Renal tubular acidosis of the gradient or classic type, thought to be due to a disorder of the distal tubule, has been found to occur in 32% of 117 patients with chronic liver disease. Whilst the cause of this disorder is probably multifactorial, immunological mechanisms are considered to play a major role. The presence of this disorder might well be a cause, rather than the result of, the various electrolyte abnormalities seen in patients with chronic liver disease. ImagesFig. 1Fig. 6 PMID:1234340

  3. Renal tubular secretion of glutathione (GSH)

    SciTech Connect

    Scott, R.D.; Curthoys, N.P.

    1986-05-01

    The rapid turnover of renal GSH may require its secretion into the tubular lumen. Renal clearance of plasma GSH was measured in rats anesthetized with Inactin and infused with (/sup 3/H)inulin. Renal ..gamma..-glutamyltranspeptidase (..gamma..GT) was then inactivated (> 97%) by infusion of acivicin and samples were collected for 6-7 h. By 4.5 h arterial and urinary GSH increased from 5..mu..M and 1.3 n mol/h to 23 ..mu..M and 2400-7000 nmol/h, respectively. The ratio of urinary GSH to filtered load increased from < 0.01 to 0.7-2.6. When renal GSH was decreased to 30% of normal by pretreating rats with buthionine sulfoximine (BSO), the subsequent inactivation of ..gamma..GT caused only a slight increase in arterial GSH and urinary GSH increased to only 400-600 nmol/h (60-70% of filtered load). The amount of GSH filtered by the kidney was reduced by initially treating a rat with acivicin and 3 h later infusing purified ..gamma..GT (0.2 mg/h) to degrade plasma GSH. Just before infusion of ..gamma..GT, arterial GSH was 23 ..mu..M and urinary GSH was equal to 90% of the filtered load. At 1 h after infusion of ..gamma..GT, arterial GSH decreased to 0.3 ..mu..M, whereas urinary GSH remained elevated (1200-1800 nmol/h) and now equalled 10-20 times the filtered load. When similar experiments were carried out in BSO treated rats, maximal urinary GSH was reduced to 200 nmol/h, a value that was still 10 times the filtered load. Therefore, secreted GSH constitutes a significant portion of the GSH that is normally catabolized within the tubular lumen.

  4. Inherited renal tubular defects with hypokalemia.

    PubMed

    Muthukrishnan, J; Modi, K D; Kumar, P Jagdish; Jha, Ratan

    2009-03-01

    Bartter's and Gitelman's syndrome are two ends of a spectrum of inherited renal tubular disorders that present with hypokalemic metabolic alkalosis of varying severity. Clinical features and associated calcium and magnesium ion abnormalities are used to diagnose these cases after excluding other commoner causes. We report on two cases, the first being a young boy, born of pregnancy complicated by polyhydramnios, who had classical dysmorphic features, polyuria, hypokalemia and hypercalciuria and was diagnosed as having Bartter's syndrome. The second patient is a lady who had recurrent tetany as the only manifestation of Gitelman's syndrome, which is an unusual presentation. Potassium replacement with supplementation of other deficient ions led to satisfactory clinical and biochemical response.

  5. Transient Distal Renal Tubular Acidosis in Organophosphate Poisoning

    PubMed Central

    Narayan, Ram; Abdulla, Mansoor C.; Alungal, Jemshad

    2017-01-01

    Renal complications due to organophosphate poisoning are very rare. We are presenting a unique case of transient distal renal tubular acidosis due to organophosphate poisoning, which to the best of our knowledge is the first of its kind. An elderly female after deliberate self-harm with ingestion of chlorpyrifos had multiple ventricular arrhythmias due to hypokalemia secondary to distal renal tubular acidosis which improved completely after treatment.

  6. Tubular reabsorption in normal renal function.

    PubMed

    O'Connor, W J

    1984-01-01

    The purpose here is to examine in relation to normal renal function three factors which might affect tubular reabsorption: (1) The reabsorption of SO4, PO4, K, Cl, HCO3 and water are all linked to the reabsorption of Na. This would amount to the reabsorption by the tubules of a net reabsorbate of a composition similar to Locke's fluid. Fixed linkage of the reabsorption of a substance to the reabsorption of Na would be a very effective way of maintaining its plasma concentration within a narrow range. The substance would be retained unless its plasma concentration exceeds a threshold value and then small increase in plasma concentration determines its excretion. (2) The rate of reabsorption of Na and substances linked to it is increased when the volume of the intraluminal fluid is increased. This would explain why there is only a small increase in the excretion of Na and other electrolytes when glomerular filtration rate is increased after a meal of meat. (3) Plasma protein concentration affects tubular reabsorption. This would explain why fall in plasma protein is a main agent determining Na excretion in normal animals. Trying to see 'how far the observed facts can be brought into accord with a theory' reveals the difficulty of applying critical tests. On the one hand, the theories are not stated quantitatively in reference to the small changes of normal life; rather the evidence is from experiments with large changes. On the other hand, the small changes within the range of normal function, while themselves statistically significant, are too small for effective investigation of circumstances which may modify them. In the examples discussed here, we cannot say more than that the theories could explain the facts and their participation cannot be excluded.

  7. Responses of proximal tubular cells to injury in congenital renal disease: fight or flight.

    PubMed

    Chevalier, Robert L; Forbes, Michael S; Galarreta, Carolina I; Thornhill, Barbara A

    2014-04-01

    Most chronic kidney disease in children results from congenital or inherited disorders, which can be studied in mouse models. Following 2 weeks of unilateral ureteral obstruction (UUO) in the adult mouse, nephron loss is due to proximal tubular mitochondrial injury and cell death. In neonatal mice, proximal tubular cell death is delayed beyond 2 weeks of complete UUO, and release of partial UUO allows remodeling of remaining nephrons. Progressive cyst expansion develops in polycystic kidney disease (PKD), a common inherited renal disorder. The polycystic kidney and fibrosis (pcy)-mutant mouse (which develops late-onset PKD) develops thinning of the glomerulotubular junction in parallel with growth of cysts in adulthood. Renal insufficiency in nephropathic cystinosis, a rare inherited renal disorder, results from progressive tubular cystine accumulation. In the Ctns knockout mouse (a model of cystinosis), proximal tubular cells become flattened, with loss of mitochondria and thickening of tubular basement membrane. In each model, persistent obstructive or metabolic stress leads ultimately to the formation of atubular glomeruli. The initial "fight" response (proximal tubular survival) switches to a "flight" response (proximal tubular cell death) with ongoing oxidative injury and mitochondrial damage. Therapies should be directed at reducing proximal tubular mitochondrial oxidative injury to enhance repair and regeneration.

  8. Responses of Proximal Tubular Cells to Injury in Congenital Renal Disease: Fight or Flight

    PubMed Central

    Chevalier, Robert L.; Forbes, Michael S.; Galarreta, Carolina I.; Thornhill, Barbara A.

    2013-01-01

    Most chronic kidney disease in children results from congenital or inherited disorders, which can be studied in mouse models. Following 2 weeks of unilateral ureteral obstruction (UUO) in the adult mouse, nephron loss is due to proximal tubular mitochondrial injury and cell death. In neonatal mice, proximal tubular cell death is delayed beyond 2 weeks of complete UUO, and release of partial UUO allows remodeling of remaining nephrons. Progressive cyst expansion develops in polycystic kidney disease (PKD), a common inherited renal disorder. The PCY mutant mouse (which develops late-onset PKD) develops thinning of the glomerulotubular junction in parallel with growth of cysts in adulthood. Renal insufficiency in nephropathic cystinosis, a rare inherited renal disorder, results from progressive tubular cystine accumulation. In the Ctns knock out mouse (a model of cystinosis), proximal tubular cells become flattened, with loss of mitochondria and thickening of tubular basement membrane. In each model, persistent obstructive or metabolic stress leads ultimately to the formation of atubular glomeruli. The initial “fight” response (proximal tubular survival) switches to a “flight” response (proximal tubular cell death) with ongoing oxidative injury and mitochondrial damage. Therapies should be directed at reducing proximal tubular mitochondrial oxidative injury to enhance repair and regeneration. PMID:23949631

  9. Distal Renal Tubular Acidosis in Infancy: A Bicarbonate Wasting State

    ERIC Educational Resources Information Center

    Rodriguez-Soriano, J.; And Others

    1975-01-01

    Studied were three unrelated infants with distal renal tubular acidosis (a condition characterized by an inability to acidify the urine to minimal pH levels resulting in the loss of bicarbonates). (DB)

  10. Distal Renal Tubular Acidosis in Infancy: A Bicarbonate Wasting State

    ERIC Educational Resources Information Center

    Rodriguez-Soriano, J.; And Others

    1975-01-01

    Studied were three unrelated infants with distal renal tubular acidosis (a condition characterized by an inability to acidify the urine to minimal pH levels resulting in the loss of bicarbonates). (DB)

  11. Benchmark Dose Estimation for Cadmium-Induced Renal Tubular Damage among Environmental Cadmium-Exposed Women Aged 35–54 Years in Two Counties of China

    PubMed Central

    Hu, Jia; Li, Mei; Han, Tian-xu; Chen, Jian-wei; Ye, Lin-xiang; Wang, Qi; Zhou, Yi-kai

    2014-01-01

    Background A number of factors, including gender, age, smoking habits, and occupational exposure, affect the levels of urinary cadmium. Few studies have considered these influences when calculating the benchmark dose (BMD) of cadmium. In the present study, we aimed to calculate BMDs and their 95% lower confidence bounds (BMDLs) for cadmium-induced renal tubular effects in an age-specific population in south-central China. Methods In this study, urinary cadmium, β2-microglobulin, and N-acetyl-β-D-glucosaminidase levels were measured in morning urine samples from 490 randomly selected non-smoking women aged 35–54 years. Participants were selected using stratified cluster sampling in two counties (counties A and B) in China. Multiple regression and logistic regression analyses were used to investigate the dose-response relationship between urinary cadmium levels and tubular effects. BMDs/BMDLs corresponding to an additional risk (benchmark response) of 5% and 10% were calculated with assumed cut-off values of the 84th and 90th percentile of urinary β2-microglobulin and N-acetyl-β-D-glucosaminidase levels of the controls. Results Urinary levels of β2-microglobulin and N-acetyl-β-D-glucosaminidase increased significantly with increasing levels of urinary cadmium. Age was not associated with urinary cadmium levels, possibly because of the narrow age range included in this study. Based on urinary β2-microglobulin and N-acetyl-β-D-glucosaminidase, BMDs and BMDLs of urinary cadmium ranged from 2.08 to 3.80 (1.41–2.18) µg/g cr for subjects in county A and from 0.99 to 3.34 (0.74–1.91) µg/g cr for those in county B. The predetermined benchmark response of 0.05 and the 90th percentiles of urinary β2-microglobulin and N-acetyl-β-D-glucosaminidase levels of the subjects not exposed to cadmium (i.e., the control group) served as cut-off values. Conclusions The obtained BMDs of urinary cadmium were similar to the reference point of 1 µg/g cr, as suggested by the

  12. mTORC1 maintains renal tubular homeostasis and is essential in response to ischemic stress.

    PubMed

    Grahammer, Florian; Haenisch, Nora; Steinhardt, Frederic; Sandner, Lukas; Sander, Lukas; Roerden, Malte; Arnold, Frederic; Cordts, Tomke; Wanner, Nicola; Reichardt, Wilfried; Kerjaschki, Dontscho; Ruegg, Markus A; Hall, Michael N; Moulin, Pierre; Busch, Hauke; Boerries, Melanie; Walz, Gerd; Artunc, Ferruh; Huber, Tobias B

    2014-07-08

    Mammalian target of rapamycin complex 1 (mTORC1) is a key regulator of cell metabolism and autophagy. Despite widespread clinical use of mTORC1 inhibitors, the role of mTORC1 in renal tubular function and kidney homeostasis remains elusive. By using constitutive and inducible deletion of conditional Raptor alleles in renal tubular epithelial cells, we discovered that mTORC1 deficiency caused a marked concentrating defect, loss of tubular cells, and slowly progressive renal fibrosis. Transcriptional profiling revealed that mTORC1 maintains renal tubular homeostasis by controlling mitochondrial metabolism and biogenesis as well as transcellular transport processes involved in countercurrent multiplication and urine concentration. Although mTORC2 partially compensated for the loss of mTORC1, exposure to ischemia and reperfusion injury exaggerated the tubular damage in mTORC1-deficient mice and caused pronounced apoptosis, diminished proliferation rates, and delayed recovery. These findings identify mTORC1 as an important regulator of tubular energy metabolism and as a crucial component of ischemic stress responses.

  13. mTORC1 maintains renal tubular homeostasis and is essential in response to ischemic stress

    PubMed Central

    Grahammer, Florian; Haenisch, Nora; Steinhardt, Frederic; Sandner, Lukas; Roerden, Malte; Arnold, Frederic; Cordts, Tomke; Wanner, Nicola; Reichardt, Wilfried; Kerjaschki, Dontscho; Ruegg, Markus A.; Hall, Michael N.; Moulin, Pierre; Busch, Hauke; Boerries, Melanie; Walz, Gerd; Artunc, Ferruh; Huber, Tobias B.

    2014-01-01

    Mammalian target of rapamycin complex 1 (mTORC1) is a key regulator of cell metabolism and autophagy. Despite widespread clinical use of mTORC1 inhibitors, the role of mTORC1 in renal tubular function and kidney homeostasis remains elusive. By using constitutive and inducible deletion of conditional Raptor alleles in renal tubular epithelial cells, we discovered that mTORC1 deficiency caused a marked concentrating defect, loss of tubular cells, and slowly progressive renal fibrosis. Transcriptional profiling revealed that mTORC1 maintains renal tubular homeostasis by controlling mitochondrial metabolism and biogenesis as well as transcellular transport processes involved in countercurrent multiplication and urine concentration. Although mTORC2 partially compensated for the loss of mTORC1, exposure to ischemia and reperfusion injury exaggerated the tubular damage in mTORC1-deficient mice and caused pronounced apoptosis, diminished proliferation rates, and delayed recovery. These findings identify mTORC1 as an important regulator of tubular energy metabolism and as a crucial component of ischemic stress responses. PMID:24958889

  14. 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.

  15. P53 inhibitor pifithrin-α prevents the renal tubular epithelial cells against injury

    PubMed Central

    Shen, Yun-Lin; Sun, Lei; Hu, Yu-Jie; Liu, Hua-Jie; Kuang, Xin-Yu; Niu, Xiao-Ling; Huang, Wen-Yan

    2016-01-01

    The injury and repair of renal tubular epithelial cells play an important role in the pathological process of acute kidney injury (AKI). This study aimed to clarify the role of cell cycle change in renal tubular epithelial cell injury and repair in vivo and in vitro. Sprague-Dawley rats received bilateral renal pedicle clamping for 45 min (ischemia) followed by reperfusion. Pifithrin-α, a p53 inhibitor, was administered at 24 h before renal ischemia and 3 and 14 days after reperfusion. Results showed the tubular epithelial cells in M phase increased significantly at 2 h to 72 h after ischemia/reperfusion (I/R), while pifithrin-α decreased them. Renal I/R caused renal tubular epithelial damage in rats, which was improved by pifithrin-α. The α-SMA mRNA expression was up-regulated significantly after I/R, while it was down-regulated by pifithrin-α.NRK-52E cells were cultured in vitro, cell damage was induced by addition of TNF-α, and then cells were treated with pifithrin-α. Cells treated with TNF-α alone in G2/M phase increased significantly, but they were reduced in the presence of pifithrin-α. In NRK-52E cells treated with pifithrin-α for 6 h, NGAL mRNA expression was significantly lower than in cells without pifithrin-α treatment. After NRK-52E cells were treated with pifithrin-α for 24 h, α-SMA and FN mRNA expression was significantly lower than in cells without the treatment. In summary, pifithrin-α can facilitate the progression of renal tubular epithelial cells through G2/M phase, protecting them against injury. PMID:27829991

  16. Renal pathophysiologic role of cortical tubular inclusion bodies.

    PubMed

    Radi, Zaher A; Stewart, Zachary S; Grzemski, Felicity A; Bobrowski, Walter F

    2013-01-01

    Renal tubular inclusion bodies are rarely associated with drug administration. The authors describe the finding of renal cortical tubular intranuclear and intracytoplasmic inclusion bodies associated with the oral administration of a norepinephrine/serotonin reuptake inhibitor (NSRI) test article in Sprague-Dawley (SD) rats. Rats were given an NSRI daily for 4 weeks, and kidney histopathologic, ultrastructural pathology, and immunohistochemical examinations were performed. Round eosinophilic intranuclear inclusion bodies were observed histologically in the tubular epithelial cells of the renal cortex in male and female SD rats given the NSRI compound. No evidence of degeneration or necrosis was noted in the inclusion-containing renal cells. By ultrastructural pathology, inclusion bodies consisted of finely granular, amorphous, and uniformly stained nonmembrane-bound material. By immunohistochemistry, inclusion bodies stained positive for d-amino acid oxidase (DAO) protein. In addition, similar inclusion bodies were noted in the cytoplasmic tubular epithelial compartment by ultrastructural and immunohistochemical examination.  This is the first description of these renal inclusion bodies after an NSRI test article administration in SD rats. Such drug-induced renal inclusion bodies are rat-specific, do not represent an expression of nephrotoxicity, represent altered metabolism of d-amino acids, and are not relevant to human safety risk assessment.

  17. Klinefelter's syndrome with renal tubular acidosis: impact on height.

    PubMed

    Jebasingh, F; Paul, T V; Spurgeon, R; Abraham, S; Jacob, J J

    2010-02-01

    A 19-year-old Indian man presented with a history of proximal muscle weakness, knock knees and gynaecomastia. On examination he had features of rickets and bilateral small testes. Karyotyping revealed a chromosomal pattern of 47,XXX, confirming the diagnosis of Klinefelter's syndrome. He was also found to have hyperchloraemic metabolic acidosis with hypokalaemia, hypophosphataemia, phosphaturia and glycosuria, which favoured a diagnosis of proximal renal tubular acidosis. Patients with Klinefelter's syndrome typically have a tall stature due to androgen deficiency, resulting in unfused epiphyses and an additional X chromosome. However, this patient had a short stature due to associated proximal renal tubular acidosis. To the best of our knowledge, this is the second case of Klinefelter's syndrome with short stature due to associated renal tubular acidosis reported in the literature. This report highlights the need to consider other causes when patients with Klinefelter's syndrome present with a short stature.

  18. Tubular cell apoptosis and cidofovir-induced acute renal failure.

    PubMed

    Ortiz, Alberto; Justo, Pilar; Sanz, Ana; Melero, Rosa; Caramelo, Carlos; Guerrero, Manuel Fernández; Strutz, Frank; Müller, Gerhard; Barat, Antonio; Egido, Jesus

    2005-01-01

    Cidofovir is an antiviral drug with activity against a wide array of DNA viruses including poxvirus. The therapeutic use of cidofovir is marred by a dose-limiting side effect, nephrotoxicity, leading to proximal tubular cell injury and acute renal failure. Treatment with cidofovir requires the routine use of prophylactic measures. A correct knowledge of the cellular and molecular mechanisms of cidofovir toxicity may lead to the development of alternative prophylactic strategies. We recently cared for a patient with irreversible acute renal failure due to cidofovir. Renal biopsy showed tubular cell apoptosis. Cidofovir induced apoptosis in primary cultures of human proximal tubular cells in a temporal (peak apoptosis at 7 days) and concentration (10-40 microg/ml) pattern consistent with that of clinical toxicity. Apoptosis was identified by the presence of hypodiploid cells, by the exposure of annexin V binding sites and by morphological features and was associated with the appearance of active caspase-3 fragments. Cell death was specific as it was also present in a human proximal tubular epithelial cell line (HK-2), but not in a human kidney fibroblast cell line, and was prevented by probenecid. An inhibitor of caspase-3 (DEVD) prevented cidofovir apoptosis. The survival factors present in serum, insulin-like growth factor-1 and hepatocyte growth factor, were also protective. The present data suggest that apoptosis induction is a mechanism contributing to cidofovir nephrotoxicity. The prophylactic administration of factors with survival activity for tubular epithelium should be further explored in cidofovir renal injury.

  19. sup 99m Tc renal tubular function agents: Current status

    SciTech Connect

    Eshima, D.; Fritzberg, A.R.; Taylor, A. Jr. )

    1990-01-01

    Orthoiodohippuric (OIH) acid labeled with 131I is a widely used renal radiopharmaceutical agent and has been the standard radiopharmaceutical agent for the measurement of effective renal plasma flow (EPRF). Limitations to the routine clinical use of 131I OIH are related to the suboptimal imaging properties of the 131I radionuclide and its relatively high radiation dose. 123I has been substituted for 131I; however, its high cost and short shelf-life have limited its widespread use. Recent work has centered on the development of a new 99mTc renal tubular function agent, which would use the optimal radionuclidic properties and availability of 99mTc and combine the clinical information provided by OIH. The search for a suitable 99mTc renal tubular function agent has focused on the diamide dithiolate (N2S2), the paraaminohippuric iminodiacetic acid (PAHIDA), and the triamide mercaptide (N3S) donor ligand systems. To date, the most promising 99mTc tubular function agent is the N3S complex: 99mTc mercaptoacetyltriglycine (99mTc MAG3). Studies in animal models in diuresis, dehydration, acid or base imbalance, ischemia, and renal artery stenosis demonstrate that 99mTc MAG3 behaves similarly to 131I OIH. A simple kit formulation is available that yields the 99mTc MAG3 complex in high radiochemical purity. Studies in normal subjects and patients indicate that 99mTc MAG3 is an excellent 99mTc renal tubular agent, but its plasma clearance is only 50% to 60% that of OIH. In an effort to develop an improved 99mTc renal tubular function agent, changes have been made in the core N3S donor ligand system, but to date no agent has been synthesized that is clinically superior to 99mTc MAG3. 61 references.

  20. Comparative physiology of renal tubular transport mechanisms.

    PubMed Central

    Long, S.; Giebisch, G.

    1979-01-01

    This manuscript discusses current concepts of glomerular filtration and tubular transport of sodium, water, potassium, and urinary acidification by vertebrate kidneys in a comparative context. Work in mammalian and amphibian nephrons receives major emphasis due to our interest in application of new techniques for investigation of cellular mechanisms; when available, data from other vertebrate classes are discussed. Images FIG. 3 PMID:395765

  1. RIPK3-Mediated Necroptosis and Apoptosis Contributes to Renal Tubular Cell Progressive Loss and Chronic Kidney Disease Progression in Rats

    PubMed Central

    Zhu, Yongjun; Cui, Hongwang; Xia, Yunfeng; Gan, Hua

    2016-01-01

    Tubulointerstitial fibrosis (TIF) is caused by the progressive loss of renal tubular cells and the consequent replacement of the extracellular matrix. The progressive depletion of renal tubular cells results from apoptosis and necroptosis; however, the relative significance of each of these cell death mechanisms at different stages during the progression of chronic kidney disease (CKD) remains unclear. We sought to explore the mechanisms of renal tubular cell death during the early and intermediate stages of chronic renal damage of subtotal nephrectomied (SNx) rats. The results of tissue histological assays indicated that the numbers of necrotic dying cells and apoptotic cells were significantly higher in kidney tissues derived from a rat model of CKD. In addition, there was a significant increase in necroptosis observed by transmission electron microscopy (TEM) and an increase in the proportion of TUNEL-positive cells in kidney tissues from SNx rats compared with control rats, and necrostatin-1 (Nec-1) could inhibit necroptosis and reduce the proportion of TUNEL-positive cells. More importantly, we observed a significant increase in the incidence of necroptosis compared with apoptosis by TEM in vivo and in vitro and a significant increase in the proportion of TUNEL-positive tubular epithelial cells that did not express caspase-3 compared with those expressing cleaved caspase-3 in vitro. Furthermore, treatment with Nec-1 and zVAD strongly reduced necroptosis- and apoptosis-mediated renal tubular cell death and decreased the levels of blood urea nitrogen and serum creatinine and tubular damage scores of SNx rats. These results suggest that necroptotic cell death plays a more significant role than apoptosis in mediating the loss of renal tubular cells in SNx rats and that effectively blocking both necroptosis and apoptosis improves renal function and tubular damage at early and intermediate stages of CKD. PMID:27281190

  2. Renal tubular leakage complicating microcephalic osteodysplastic primordial dwarfism.

    PubMed Central

    Eason, J; Hall, C M; Trounce, J Q

    1995-01-01

    We describe a male infant with phenotypic and radiological features of microcephalic osteodysplastic primordial dwarfism type I/III. He showed severe osteoporosis and biochemical derangement owing to renal tubular leakage, which has not previously been reported in this condition. He died aged 5 months. Images PMID:7783178

  3. Osteomalacia associated with increased renal tubular resorption of phosphate (hypohyperparathyroidism)

    PubMed Central

    Kanis, J. A.; Walton, R. J.

    1976-01-01

    A 12-year-old girl, who presented with joint pains, was found to have hypocalcaemia, hyperphosphataemia due to increased renal tubular reabsorption, increased serum alkaline phosphatase activity, and osteomalacia. These features, which resemble those found in so-called hypohyperparathyroidism, were all rapidly reversed by small doses of cholecalciferol. PMID:183195

  4. Amino acid infusion blocks renal tubular uptake of an indium-labelled somatostatin analogue.

    PubMed Central

    Hammond, P. J.; Wade, A. F.; Gwilliam, M. E.; Peters, A. M.; Myers, M. J.; Gilbey, S. G.; Bloom, S. R.; Calam, J.

    1993-01-01

    The Indium-labelled somatostatin analogue pentetreotide has been successfully developed for imaging of somatostatin receptor positive tumours. However there is significant renal tubular uptake of the radiolabelled peptide, which can obscure upper abdominal tumours and would preclude its use for targeted radiotherapy. The aim of this study was to determine whether amino acid infusion, which has been shown to block renal tubular peptide reabsorption, diminishes renal parenchymal uptake of this radiolabelled analogue. Eight patients being scanned with the 111In-labelled somatostatin analogue, pentetreotide, for localisation of gastroenteropancreatic tumours received an infusion of synthetic amino acids. The ratio of isotope uptake in kidney to that in spleen was assessed, and compared to the ratio for matched control patients, to determine if amino acid infusion reduced renal parenchymal uptake of the radiopharmaceutical. The amount of isotope in the urine was determined to ensure that any effect of the amino acid infusion was unrelated to changes in clearance. Infusion of amino acids significantly reduced renal parenchymal uptake of isotope at 4 h. There was a non-significant increase in urinary clearance of isotope over the 4 h, consistent with reduced reuptake and a lack of effect on glomerular filtration rate. This technique, by preventing renal damage, may allow the use of this somatostatin analogue for local radiotherapy, and could be of wider value in blocking tubular re-uptake of potentially nephrotoxic agents, such as radiolabelled Fab fragments. Images Figure 1 PMID:8099808

  5. Ibuprofen-related renal tubular acidosis in pregnancy.

    PubMed

    Mallett, Andrew; Lynch, Matthew; John, George T; Healy, Helen; Lust, Karin

    2011-09-01

    Ibuprofen-related renal tubular acidosis (RTA) has not been previously described in pregnancy but its occurrence outside of pregnancy is being increasingly described. In this case, a 34-year-old woman presented in the third trimester of pregnancy with Type 1 or distal RTA related to ibuprofen and codeine abuse. It was complicated by acute on chronic renal dysfunction and hypokalemia. Delivery at 37 weeks gestation due to concerns of evolving preeclampsia resulted in the birth of a healthy neonate. RTA and hypokalemia were remediated and ibuprofen and codeine abuse ceased. Some renal dysfunction however continued. Thorough and repeated history taking as well as vigilance for this condition is suggested.

  6. AUTOLOGOUS IMMUNE COMPLEX NEPHRITIS INDUCED WITH RENAL TUBULAR ANTIGEN

    PubMed Central

    Glassock, Richard J.; Edgington, Thomas S.; Watson, J. Ian; Dixon, Frank J.

    1968-01-01

    The pathogenetic mechanism involved in a form of experimental allergic glomerulonephritis induced by immunization of rats with renal tubular antigen has been investigated. A single immunization with less than a milligram of a crude renal tubular preparation, probably containing less than 25 µg of the specific nephritogenic antigen, is effective in the induction of this form of chronic membranous glomerulonephritis. In the nephritic kidney autologous nephritogenic tubular antigen is found in the glomerular deposits along with γ-globulin and complement. When large amounts of antigen are injected during induction of the disease the exogenous immunizing antigen can also be detected in the glomerular deposits. It appears that this disease results from the formation of circulating antibodies capable of reacting with autologous renal tubular antigen(s) and the deposition of these antibodies and antigen(s) plus complement apparently as immune complexes in the glomeruli. This pathogenetic system has been termed an autologous immune complex disease and the resultant glomerulonephritis has been similarly designated. PMID:4169966

  7. Developmental changes in renal tubular transport-an overview.

    PubMed

    Gattineni, Jyothsna; Baum, Michel

    2015-12-01

    The adult kidney maintains a constant volume and composition of extracellular fluid despite changes in water and salt intake. The neonate is born with a kidney that has a small fraction of the glomerular filtration rate of the adult and immature tubules that function at a lower capacity than that of the mature animal. Nonetheless, the neonate is also able to maintain a constant extracellular fluid volume and composition. Postnatal renal tubular development was once thought to be due to an increase in the transporter abundance to meet the developmental increase in glomerular filtration rate. However, postnatal renal development of each nephron segment is quite complex. There are isoform changes of several transporters as well as developmental changes in signal transduction that affect the capacity of renal tubules to reabsorb solutes and water. This review will discuss neonatal tubular function with an emphasis on the differences that have been found between the neonate and adult. We will also discuss some of the factors that are responsible for the maturational changes in tubular transport that occur during postnatal renal development.

  8. Tubular Peroxiredoxin 3 as a Predictor of Renal Recovery from Acute Tubular Necrosis in Patients with Chronic Kidney Disease

    PubMed Central

    Wu, Chia-Lin; Su, Tzu-Cheng; Chang, Chia-Chu; Kor, Chew-Teng; Chang, Chung-Ho; Yang, Tao-Hsiang; Chiu, Ping-Fang; Tarng, Der-Cherng

    2017-01-01

    Peroxiredoxin 3 (PRX3) is a mitochondrial antioxidant that regulates apoptosis in various cancers. However, whether tubular PRX3 predicts recovery of renal function following acute kidney injury (AKI) remains unknown. This retrospective cohort study included 54 hospitalized patients who had AKI with biopsy-proven acute tubular necrosis (ATN). The study endpoint was renal function recovery within 6 months. Of the 54 enrolled patients, 25 (46.3%) had pre-existing chronic kidney disease (CKD) and 33 (61%) recovered renal function. Tubular PRX3 expression was higher in patients with ATN than in those without renal function recovery. The level of tubular but not glomerular PRX3 expression predicted renal function recovery from AKI (AUROC = 0.76). In multivariate Cox regression analysis, high PRX3 expression was independently associated with a higher probability of renal function recovery (adjusted hazard ratio = 8.99; 95% CI 1.13–71.52, P = 0.04). Furthermore, the discriminative ability of the clinical model for AKI recovery was improved by adding tubular PRX3. High tubular PRX3 expression was associated with a higher probability of renal function recovery from ATN. Therefore, tubular PRX3 in combination with conventional predictors can further improve recovery prediction and may help with risk stratification in AKI patients with pre-existing CKD. PMID:28240739

  9. Tubular Peroxiredoxin 3 as a Predictor of Renal Recovery from Acute Tubular Necrosis in Patients with Chronic Kidney Disease.

    PubMed

    Wu, Chia-Lin; Su, Tzu-Cheng; Chang, Chia-Chu; Kor, Chew-Teng; Chang, Chung-Ho; Yang, Tao-Hsiang; Chiu, Ping-Fang; Tarng, Der-Cherng

    2017-02-27

    Peroxiredoxin 3 (PRX3) is a mitochondrial antioxidant that regulates apoptosis in various cancers. However, whether tubular PRX3 predicts recovery of renal function following acute kidney injury (AKI) remains unknown. This retrospective cohort study included 54 hospitalized patients who had AKI with biopsy-proven acute tubular necrosis (ATN). The study endpoint was renal function recovery within 6 months. Of the 54 enrolled patients, 25 (46.3%) had pre-existing chronic kidney disease (CKD) and 33 (61%) recovered renal function. Tubular PRX3 expression was higher in patients with ATN than in those without renal function recovery. The level of tubular but not glomerular PRX3 expression predicted renal function recovery from AKI (AUROC = 0.76). In multivariate Cox regression analysis, high PRX3 expression was independently associated with a higher probability of renal function recovery (adjusted hazard ratio = 8.99; 95% CI 1.13-71.52, P = 0.04). Furthermore, the discriminative ability of the clinical model for AKI recovery was improved by adding tubular PRX3. High tubular PRX3 expression was associated with a higher probability of renal function recovery from ATN. Therefore, tubular PRX3 in combination with conventional predictors can further improve recovery prediction and may help with risk stratification in AKI patients with pre-existing CKD.

  10. Synchronized renal tubular cell death involves ferroptosis.

    PubMed

    Linkermann, Andreas; Skouta, Rachid; Himmerkus, Nina; Mulay, Shrikant R; Dewitz, Christin; De Zen, Federica; Prokai, Agnes; Zuchtriegel, Gabriele; Krombach, Fritz; Welz, Patrick-Simon; Weinlich, Ricardo; Vanden Berghe, Tom; Vandenabeele, Peter; Pasparakis, Manolis; Bleich, Markus; Weinberg, Joel M; Reichel, Christoph A; Bräsen, Jan Hinrich; Kunzendorf, Ulrich; Anders, Hans-Joachim; Stockwell, Brent R; Green, Douglas R; Krautwald, Stefan

    2014-11-25

    Receptor-interacting protein kinase 3 (RIPK3)-mediated necroptosis is thought to be the pathophysiologically predominant pathway that leads to regulated necrosis of parenchymal cells in ischemia-reperfusion injury (IRI), and loss of either Fas-associated protein with death domain (FADD) or caspase-8 is known to sensitize tissues to undergo spontaneous necroptosis. Here, we demonstrate that renal tubules do not undergo sensitization to necroptosis upon genetic ablation of either FADD or caspase-8 and that the RIPK1 inhibitor necrostatin-1 (Nec-1) does not protect freshly isolated tubules from hypoxic injury. In contrast, iron-dependent ferroptosis directly causes synchronized necrosis of renal tubules, as demonstrated by intravital microscopy in models of IRI and oxalate crystal-induced acute kidney injury. To suppress ferroptosis in vivo, we generated a novel third-generation ferrostatin (termed 16-86), which we demonstrate to be more stable, to metabolism and plasma, and more potent, compared with the first-in-class compound ferrostatin-1 (Fer-1). Even in conditions with extraordinarily severe IRI, 16-86 exerts strong protection to an extent which has not previously allowed survival in any murine setting. In addition, 16-86 further potentiates the strong protective effect on IRI mediated by combination therapy with necrostatins and compounds that inhibit mitochondrial permeability transition. Renal tubules thus represent a tissue that is not sensitized to necroptosis by loss of FADD or caspase-8. Finally, ferroptosis mediates postischemic and toxic renal necrosis, which may be therapeutically targeted by ferrostatins and by combination therapy.

  11. Renal tubular vasopressin receptors downregulated by dehydration

    SciTech Connect

    Steiner, M.; Phillips, M.I. )

    1988-03-01

    Receptors for arginine vasopressin (AVP) were characterized in tubular epithelial basolateral membranes (BL membranes) prepared from the kidneys of male Spraque-Dawley rats. Association of ({sup 3}H)AVP was rapid, reversible, and specific. Saturation studies revealed a single class of saturable binding sites with a maximal binding (B{sub max}) of 184 {plus minus} 15 fmol/mg protein. The V{sub 2} receptor antagonist was more than 3,700 times as effective in displacing ({sup 3}H)AVP than was the V{sub 1} antagonist. To investigate the physiological regulation of vasopressin receptors, the effects of elevated levels of circulating AVP on receptor characteristics were studied. Seventy-two-hour water deprivation significantly elevated plasma osmolality and caused an 11.5-fold increase in plasma (AVP). Scatchard analysis revealed a 38% decreased in the number of AVP receptors on the BL membranes from dehydrated animals. The high-affinity binding sites on the BL membranes fit the pharmacological profile for adenylate cyclase-linked vasopressin receptors (V{sub 2}), which mediate the antidiuretic action of the hormone. The authors conclude that physiologically elevated levels of AVP can downregulate vasopressin receptors in the kidney.

  12. Autophagy protects renal tubular cells against cyclosporine toxicity.

    PubMed

    Pallet, Nicolas; Bouvier, Nicolas; Legendre, Christophe; Gilleron, Jerome; Codogno, Patrice; Beaune, Philippe; Thervet, Eric; Anglicheau, Dany

    2008-08-01

    A major side effect of the powerful immunosuppressive drug cyclosporine (CsA) is the development of a chronic nephrotoxicity whose mechanisms are not fully understood. Recent data suggest that tubular cells play a central role in the pathogenesis of chronic nephropathies. We have shown that CsA is responsible for endoplasmic reticulum (ER) stress in tubular cells. Autophagy has recently been described to be induced by ER stress and to alleviate its deleterious effects. In this study, we demonstrate that CsA induces autophagy in primary cultured human renal tubular cells through LC3II expression and autophagosomes visualization by electron microscopy. Autophagy is dependant on ER stress because various ER stress inducers activate autophagy, and salubrinal, an inhibitor of eIF2alpha dephosphorylation that protects cells against ER stress, inhibited LC3II expression. Furthermore, autophagy inhibition during CsA treatment with beclin1 siRNA significantly increases tubular cell death. Finally, immunohistochemical analysis of rat kidneys demonstrates a positive LC3 staining on injured tubular cells, suggesting that CsA induces autophagy in vivo. Taken together, these results demonstrate that CsA, through ER stress induction, activates autophagy as a protection against cell death.

  13. Competitive inhibition of renal tubular secretion of gemifloxacin by probenecid.

    PubMed

    Landersdorfer, Cornelia B; Kirkpatrick, Carl M J; Kinzig, Martina; Bulitta, Jürgen B; Holzgrabe, Ulrike; Drusano, George L; Sörgel, Fritz

    2009-09-01

    Probenecid interacts with transport processes of drugs at several sites in the body. For most quinolones, renal clearance is reduced by concomitant administration of probenecid. The interaction between gemifloxacin and probenecid has not yet been studied. We studied the extent, time course, site(s), and mechanism of this interaction. Seventeen healthy volunteers participated in a randomized, two-way crossover study. Subjects received 320 mg gemifloxacin as an oral tablet without and with 4.5 g probenecid divided in eight oral doses. Drug concentrations in plasma and urine were analyzed by liquid chromatography-tandem mass spectrometry. WinNonlin was used for noncompartmental analysis, compartmental modeling, and statistics, and NONMEM was used for visual predictive checks. Concomitant administration of probenecid increased plasma gemifloxacin concentrations and amounts excreted in urine compared to baseline amounts. Data are average estimates (percent coefficients of variation). Modeling showed a competitive inhibition of the renal tubular secretion of gemifloxacin by probenecid as the most likely mechanism of the interaction. The estimated K(m) and Vmax for the saturable part of renal elimination were 9.16 mg/liter (20%) and 113 mg/h (21%), respectively. Based on the molar ratio, the affinity for the renal transporter was 10-fold higher for gemifloxacin than for probenecid. Since probenecid reached an approximately 200-times-higher area under the molar concentration-time curve from 0 to 24 h than gemifloxacin, probenecid inhibited the active tubular secretion of gemifloxacin. Probenecid also reduced the nonrenal clearance of gemifloxacin from 25.2 (26%) to 21.0 (23%) liters/h. Probenecid inhibited the renal tubular secretion of gemifloxacin, most likely by a competitive mechanism, and slightly decreased nonrenal clearance of gemifloxacin.

  14. Competitive Inhibition of Renal Tubular Secretion of Gemifloxacin by Probenecid▿

    PubMed Central

    Landersdorfer, Cornelia B.; Kirkpatrick, Carl M. J.; Kinzig, Martina; Bulitta, Jürgen B.; Holzgrabe, Ulrike; Drusano, George L.; Sörgel, Fritz

    2009-01-01

    Probenecid interacts with transport processes of drugs at several sites in the body. For most quinolones, renal clearance is reduced by concomitant administration of probenecid. The interaction between gemifloxacin and probenecid has not yet been studied. We studied the extent, time course, site(s), and mechanism of this interaction. Seventeen healthy volunteers participated in a randomized, two-way crossover study. Subjects received 320 mg gemifloxacin as an oral tablet without and with 4.5 g probenecid divided in eight oral doses. Drug concentrations in plasma and urine were analyzed by liquid chromatography-tandem mass spectrometry. WinNonlin was used for noncompartmental analysis, compartmental modeling, and statistics, and NONMEM was used for visual predictive checks. Concomitant administration of probenecid increased plasma gemifloxacin concentrations and amounts excreted in urine compared to baseline amounts. Data are average estimates (percent coefficients of variation). Modeling showed a competitive inhibition of the renal tubular secretion of gemifloxacin by probenecid as the most likely mechanism of the interaction. The estimated Km and Vmax for the saturable part of renal elimination were 9.16 mg/liter (20%) and 113 mg/h (21%), respectively. Based on the molar ratio, the affinity for the renal transporter was 10-fold higher for gemifloxacin than for probenecid. Since probenecid reached an ∼200-times-higher area under the molar concentration-time curve from 0 to 24 h than gemifloxacin, probenecid inhibited the active tubular secretion of gemifloxacin. Probenecid also reduced the nonrenal clearance of gemifloxacin from 25.2 (26%) to 21.0 (23%) liters/h. Probenecid inhibited the renal tubular secretion of gemifloxacin, most likely by a competitive mechanism, and slightly decreased nonrenal clearance of gemifloxacin. PMID:19564368

  15. Tubular Overexpression of Angiopoietin-1 Attenuates Renal Fibrosis

    PubMed Central

    Lee, Heedoo; Kim, Yeawon; Liu, Tuoen; Guo, Qiusha; Geminiani, Julio J.; Austin, Paul F.; Chen, Ying Maggie

    2016-01-01

    Emerging evidence has highlighted the pivotal role of microvasculature injury in the development and progression of renal fibrosis. Angiopoietin-1 (Ang-1) is a secreted vascular growth factor that binds to the endothelial-specific Tie2 receptor. Ang-1/Tie2 signaling is critical for regulating blood vessel development and modulating vascular response after injury, but is dispensable in mature, quiescent vessels. Although dysregulation of vascular endothelial growth factor (VEGF) signaling has been well studied in renal pathologies, much less is known about the role of the Ang-1/Tie2 pathway in renal interstitial fibrosis. Previous studies have shown contradicting effects of overexpressing Ang-1 systemically on renal tubulointerstitial fibrosis when different engineered forms of Ang-1 are used. Here, we investigated the impact of site-directed expression of native Ang-1 on the renal fibrogenic process and peritubular capillary network by exploiting a conditional transgenic mouse system [Pax8-rtTA/(TetO)7 Ang-1] that allows increased tubular Ang-1 production in adult mice. Using a murine unilateral ureteral obstruction (UUO) fibrosis model, we demonstrate that targeted Ang-1 overexpression attenuates myofibroblast activation and interstitial collagen I accumulation, inhibits the upregulation of transforming growth factor β1 and subsequent phosphorylation of Smad 2/3, dampens renal inflammation, and stimulates the growth of peritubular capillaries in the obstructed kidney. Our results suggest that Ang-1 is a potential therapeutic agent for targeting microvasculature injury in renal fibrosis without compromising the physiologically normal vasculature in humans. PMID:27454431

  16. Renal tubular Notch signaling triggers a prosenescent state after acute kidney injury.

    PubMed

    Sörensen-Zender, Inga; Rong, Song; Susnik, Nathan; Zender, Steffen; Pennekamp, Petra; Melk, Anette; Haller, Hermann; Schmitt, Roland

    2014-04-15

    The aging kidney has a diminished regenerative potential and an increased tendency to develop tubular atrophy and fibrosis after acute injury. In this study, we found that activation of tubular epithelial Notch1 signaling was prolonged in the aging kidney after ischemia/reperfusion (IR) damage. To analyze the consequences of sustained Notch activation, we generated mice with conditional inducible expression of Notch1 intracellular domain (NICD) in proximal tubules. NICD kidneys were analyzed 1 and 4 wk after renal IR. Conditional NICD expression was associated with aggravated tubular damage, a fibrotic phenotype, and the expression of cellular senescence markers p21 and p16(INK4a). In wild-type mice pharmacological inhibition of Notch using the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) improved tubulo-interstitial damage and antagonized the prosenescent pathway activation after IR. In vitro, activation of Notch signaling with delta-like-ligand-4 caused prosenescent changes in tubular cells while inhibition with DAPT attenuated these changes. In conclusion, our data suggest that sustained epithelial Notch activation after IR might contribute to the inferior outcome of old kidneys after injury. Sustained epithelial activation of Notch is associated with a prosenescent phenotype and maladaptive repair.

  17. Tweak induces proliferation in renal tubular epithelium: a role in uninephrectomy induced renal hyperplasia

    PubMed Central

    Sanz, Ana B; Sanchez-Niño, Maria Dolores; Izquierdo, Maria Concepcion; Jakubowski, Aniela; Justo, Pilar; Blanco-Colio, Luis M; Ruiz-Ortega, Marta; Egido, Jesús; Ortiz, Alberto

    2009-01-01

    The tumour necrosis factor (TNF) family member TWEAK activates the Fn14 receptor and has pro-apoptotic, proliferative and pro-inflammatory actions that depend on the cell type and the microenvironment. We explored the proliferative actions of TWEAK on cultured tubular cells and in vivo on renal tubules. Additionally, we studied the role of TWEAK in compensatory proliferation following unilateral nephrectomy and in an inflammatory model of acute kidney injury (AKI) induced by a folic acid overdose. TWEAK increased the proliferation, cell number and cyclin D1 expression of cultured tubular cells, in vitro. Exposure to serum increased TWEAK and Fn14 expression and the proliferative response to TWEAK. TWEAK activated the mitogen-activated protein kinases ERK and p38, the phosphatidyl-inositol 3-kinase (PI3K)/Akt pathway and NF-κB. TWEAK-induced proliferation was prevented by inhibitors of these protein kinases and by the NF-κB inhibitor parthenolide. TWEAK-induced tubular cell proliferation as assessed by PCNA and cyclin D1 expression in the kidneys of adult healthy mice in vivo. By contrast, TWEAK knock-out mice displayed lower tubular cell proliferation in the remnant kidney following unilateral nephrectomy, a non-inflammatory model. This is consistent with TWEAK-induced proliferation on cultured tubular cells in the absence of inflammatory cytokines. Consistent with our previously published data, in the presence of inflammatory cytokines TWEAK promoted apoptosis, not proliferation, of cultured tubular cells. In this regard, TWEAK knock-out mice with AKI displayed less tubular apoptosis and proliferation, as well as improved renal function. In conclusion, TWEAK actions in tubular cells are context dependent. In a non-inflammatory milieu TWEAK induces proliferation of tubular epithelium. This may be relevant for compensatory renal hyperplasia following nephrectomy. PMID:19426154

  18. [Renal tubular acidosis with severe hypokalemic tetraparesis after ibuprofen intake].

    PubMed

    Gaul, C; Heckmann, J G; Druschky, A; Schöcklmann, H; Neundörfer, B; Erbguth, F

    1999-04-23

    A 72-year-old woman was admitted because of severe acute tetraparesis, more marked proximally. For six months she had been taking ibuprofen, up to 4800 mg daily, for a painful ulcer of the lower leg. Biochemical tests revealed marked hypokalaemia (serum potassium 1.4 mmol/l) with a metabolic acidosis (pH 7.29). The ECG showed changes of hypokalaemia (ST-segment depression and U wave). Within two days of administering potassium and bicarbonate the pareses completely regressed. Transitorily abnormal renal functions also rapidly normalized after ibuprofen had been discontinued. The biochemical findings suggest renal tubular acidosis, type 2, most likely caused by the excess intake of ibuprofen, a drug which can cause renal dysfunctions with life-threatening electrolyte abnormalities.

  19. Ibuprofen-related renal tubular acidosis in pregnancy

    PubMed Central

    Mallett, Andrew; Lynch, Matthew; John, George T; Healy, Helen; Lust, Karin

    2011-01-01

    Ibuprofen-related renal tubular acidosis (RTA) has not been previously described in pregnancy but its occurrence outside of pregnancy is being increasingly described. In this case, a 34-year-old woman presented in the third trimester of pregnancy with Type 1 or distal RTA related to ibuprofen and codeine abuse. It was complicated by acute on chronic renal dysfunction and hypokalemia. Delivery at 37 weeks gestation due to concerns of evolving preeclampsia resulted in the birth of a healthy neonate. RTA and hypokalemia were remediated and ibuprofen and codeine abuse ceased. Some renal dysfunction however continued. Thorough and repeated history taking as well as vigilance for this condition is suggested. PMID:27579107

  20. New Markers of Inflammation and Tubular Damage in Children with Chronic Kidney Disease

    PubMed Central

    Bargenda, Agnieszka; Zwolińska, Danuta

    2017-01-01

    Introduction and Aims Monocyte chemoattractant protein- (MCP-) 1, macrophage colony-stimulating factor (MCSF), and neopterin are connected with monocyte migration and transition into macrophages, leading to fibrosis and tubular damage in the course of CKD. The aim of the study was to analyze the applicability of urinary fractional excretion (FE) of MCP1, MCSF, and neopterin, as markers of inflammation and tubular damage, in children with CKD. Methods The study group consisted of 61 children with CKD stages 1–5 and 23 age-matched controls. The serum and urine concentrations of MCP1, MCSF, and neopterin were assessed by ELISA and then the fractional excretion (FE) was calculated. Results FE MCSF and neopterin values exceeded 1% already in controls. FE MCSF rose significantly since CKD stages 1-2, FE neopterin since CKD stages 3–5. FE MCP1 was below 1% in healthy controls and in CKD stages 1-2, then increased significantly in CKD stages 3–5. Conclusions The FE MCP-1 values show that inflammation precedes the tubular dysfunction. FE MCSF and FE neopterin may be considered new markers of the renal parenchyma progressive damage. Fractional excretion may become a useful tool in the assessment of inflammation and tubular damage in children with CKD. PMID:28808355

  1. Hypophosphatemic rickets due to perturbations in renal tubular function.

    PubMed

    Penido, Maria Goretti M G; Alon, Uri S

    2014-03-01

    The common denominator for all types of rickets is hypophosphatemia, leading to inadequate supply of the mineral to the growing bone. Hypophosphatemia can result from insufficient uptake of the mineral from the gut or its disproportionate losses in the kidney, the latter being caused by either tubular abnormalities per se or the effect on the tubule of circulating factors like fibroblast growth factor-23 and parathyroid hormone (PTH). High serum levels of the latter result in most cases from abnormalities in vitamin D metabolism which lead to decreased calcium absorption in the gut and hypocalcemia, triggering PTH secretion. Rickets is a disorder of the growth plate and hence pediatric by definition. However, it is important to recognize that the effect of hypophosphatemia on other parts of the skeleton results in osteomalacia in both children and adults. This review addresses the etiology, pathophysiologic mechanisms, clinical manifestations and treatment of entities associated with hypophosphatemic rickets due to perturbations in renal tubular function.

  2. Erythropoietin reduces cumulative nephrotoxicity from cisplatin and enhances renal tubular cell proliferation.

    PubMed

    Zafirov, Dimce; Petrusevska, G; Sikole, Aleksandar; Trojacanec, J; Labacevski, N; Kostova, E; Jakovski, K; Atanasovska, E; Petrov, S

    2008-12-01

    Cisplatin, a heavy metal complex, is one of the most active drugs used in the treatment of several human malignancies. However, high-dose therapy with cisplatin is limited by its cumulative nephrotoxicity. The main objectives of this study were to determine the role of recombinant human erythropoietin (Epoetin alfa) in the prevention of nephrotoxicity induced experimentally in Wistar rats by long-term administration of cisplatin (2 mg/kg/b.w./week) over eight weeks, and an evaluation of its effect on renal tubular cell proliferation. The animals were randomly assigned into three groups, each including 25 rats. Group 1 (CP) received only cisplatin (2 mg/kg/b.w./week), group 2 (CP+EPO) received cisplatin (2 mg/kg/b.w./week) and epoetin alfa (150 IE/kg/b.w./three times a week), and group 3 (control group) received only saline. During the study, the following tests for the assessment of the renal function and renal damages were performed: determination of concentration of serum creatinine and BUN and determination of total protein quantity in 24-hour urine samples. At the end of the study, the abdomen was opened and both kidneys of the rats were removed and sent for histological and morphometric analysis. Ki-67 was used as a tool to determine a proliferative index. The results obtained have shown that epoetin alfa significantly reduced the functional renal failures and renal damages, and increased toleration of high doses of cisplatin. At the same time, our results with regard to tubular proliferative index have confirmed that one of the possible mechanisms by which erythropoietin accomplishes its renoprotective effect is stimulation of tubular cell proliferation and regeneration.

  3. Clinical review: Renal tubular acidosis – a physicochemical approach

    PubMed Central

    Ring, Troels; Frische, Sebastian; Nielsen, Søren

    2005-01-01

    The Canadian physiologist PA Stewart advanced the theory that the proton concentration, and hence pH, in any compartment is dependent on the charges of fully ionized and partly ionized species, and on the prevailing CO2 tension, all of which he dubbed independent variables. Because the kidneys regulate the concentrations of the most important fully ionized species ([K+], [Na+], and [Cl-]) but neither CO2 nor weak acids, the implication is that it should be possible to ascertain the renal contribution to acid–base homeostasis based on the excretion of these ions. One further corollary of Stewart's theory is that, because pH is solely dependent on the named independent variables, transport of protons to and from a compartment by itself will not influence pH. This is apparently in great contrast to models of proton pumps and bicarbonate transporters currently being examined in great molecular detail. Failure of these pumps and cotransporters is at the root of disorders called renal tubular acidoses. The unquestionable relation between malfunction of proton transporters and renal tubular acidosis represents a problem for Stewart theory. This review shows that the dilemma for Stewart theory is only apparent because transport of acid–base equivalents is accompanied by electrolytes. We suggest that Stewart theory may lead to new questions that must be investigated experimentally. Also, recent evidence from physiology that pH may not regulate acid–base transport is in accordance with the concepts presented by Stewart. PMID:16356241

  4. Early detection of renal damage and disease in dogs and cats.

    PubMed

    Grauer, Gregory F

    2005-05-01

    Renal damage and disease can be caused by acute or chronic insults to the kidney. Acute renal damage often results from ischemic or toxic insults and usually affects the tubular portion of the nephron. In contrast, chronic renal disease can be caused by diseases and/or disorders that affect any portion of the nephron, including its blood supply and supporting interstitium. Early detection of acute renal disease facilitates appropriate intervention that can arrest or at least attenuate tubular cell damage and the development of established acute renal failure. Similarly,early detection of chronic renal disease, before the onset of renal azotemia and chronic renal failure, should facilitate appropriate intervention that stabilizes renal function or at least slows its progressive decline.

  5. Type 4 renal tubular acidosis in a kidney transplant recipient.

    PubMed

    Kulkarni, Manjunath

    2016-02-01

    We report a case of a 66-year-old diabetic patient who presented with muscle weakness 2 weeks after kidney transplantation. Her immunosuppressive regimen included tacrolimus, mycophenolate mofetil, and steroids. She was found to have hyperkalemia and normal anion gap metabolic acidosis. Tacrolimus levels were in therapeutic range. All other drugs such as beta blockers and trimethoprim - sulfamethoxazole were stopped. She did not respond to routine antikalemic measures. Further evaluation revealed type 4 renal tubular acidosis. Serum potassium levels returned to normal after starting sodium bicarbonate and fludrocortisone therapy. Though hyperkalemia is common in kidney transplant recipients, determining exact cause can guide specific treatment.

  6. Hyperammonaemia in a child with distal renal tubular acidosis.

    PubMed

    Seracini, D; Poggi, G M; Pela, I

    2005-11-01

    A 5-month-old girl with distal renal tubular acidosis (RTA) and hyperammonaemia that had lasted for 12 days, despite metabolic acidosis correction, is presented in this report. The patient showed failure to thrive, poor feeding, hypotonia and vomiting crisis in absence of inborn errors of metabolism. Probably, hyperammonaemia was the result of an imbalance between the increased ammonia synthesis, in response to metabolic acidosis, and the impaired ammonia excretion, typical of distal RTA. Our case confirms that hyperammonaemia may be observed in distal RTA, mimicking an inborn error of metabolism, and it underlines that hyperammonaemia may persist several days after metabolic acidosis correction.

  7. Inhibin-A and Decorin Secreted by Human Adult Renal Stem/Progenitor Cells Through the TLR2 Engagement Induce Renal Tubular Cell Regeneration.

    PubMed

    Sallustio, Fabio; Curci, Claudia; Aloisi, Alessandra; Toma, Chiara Cristina; Marulli, Elisabetta; Serino, Grazia; Cox, Sharon Natasha; De Palma, Giuseppe; Stasi, Alessandra; Divella, Chiara; Rinaldi, Rosaria; Schena, Francesco Paolo

    2017-08-15

    Acute kidney injury (AKI) is a public health problem worldwide. Several therapeutic strategies have been made to accelerate recovery and improve renal survival. Recent studies have shown that human adult renal progenitor cells (ARPCs) participate in kidney repair processes, and may be used as a possible treatment to promote regeneration in acute kidney injury. Here, we show that human tubular ARPCs (tARPCs) protect physically injured or chemically damaged renal proximal tubular epithelial cells (RPTECs) by preventing cisplatin-induced apoptosis and enhancing proliferation of survived cells. tARPCs without toll-like receptor 2 (TLR2) expression or TLR2 blocking completely abrogated this regenerative effect. Only tARPCs, and not glomerular ARPCs, were able to induce tubular cell regeneration process and it occurred only after damage detection. Moreover, we have found that ARPCs secreted inhibin-A and decorin following the RPTEC damage and that these secreted factors were directly involved in cell regeneration process. Polysaccharide synthetic vesicles containing these molecules were constructed and co-cultured with cisplatin damaged RPTECs. These synthetic vesicles were not only incorporated into the cells, but they were also able to induce a substantial increase in cell number and viability. The findings of this study increase the knowledge of renal repair processes and may be the first step in the development of new specific therapeutic strategies for renal repair.

  8. [Case of distal renal tubular acidosis complicated with renal diabetes insipidus, showing aggravation of symptoms with occurrence of diabetes mellitus].

    PubMed

    Liu, Hexing; Tomoda, Fumihiro; Koike, Tsutomu; Ohara, Maiko; Nakagawa, Taizo; Kagitani, Satoshi; Inoue, Hiroshi

    2011-01-01

    We report herein a 27-year-old male case of inherited distal renal tubular acidosis complicated with renal diabetes insipidus, the symptoms of which were aggravated by the occurrence of diabetes mellitus. At 2 months after birth, he was diagnosed as having inherited distal renal tubular acidosis and thereafter supplementation of both potassium and alkali was started to treat his hypokalemia and metabolic acidosis. At the age of 4 years, calcification of the bilateral renal medulla was detected by computed tomography. Subsequently his urinary volume gradually increased and polyuria of approximately 4 L/day persisted. At the age of 27 years, he became fond of sugar-sweetened drinks and also often forgot to take the medicine. He was admitted to our hospital due to polyuria of more than 10 L day, muscle weakness and gait disturbance. Laboratory tests disclosed worsening of both hypokalemia and metabolic acidosis in addition to severe hyperglycemia. It seemed likely that occurrence of diabetes mellitus and cessation of medications can induce osmotic diuresis and aggravate hypokalemia and metabolic acidosis. Consequently, severe dehydration, hypokalemia-induced damage of his urinary concentration ability and enhancement of the renin angiotensin system occurred and thereby possibly worsened his hypokalemia and metabolic acidosis. As normalization of hyperglycemia and metabolic acidosis might have exacerbated hypokalemia further, dehydration and hypokalemia were treated first. Following intensive treatment, these abnormalities were improved, but polyuria persisted. Elevated plasma antidiuretic hormone (12.0 pg/mL) and deficit of renal responses to antidiuretic hormone suggested that the polyuria was attributable to the preexisting renal diabetes insipidus possibly caused by bilateral renal medulla calcification. Thiazide diuretic or nonsteroidal anti-inflammatory drugs were not effective for the treatment of diabetes insipidus in the present case.

  9. Angiotensin II induces apoptosis in renal proximal tubular cells.

    PubMed

    Bhaskaran, Madhu; Reddy, Krishna; Radhakrishanan, Neetu; Franki, Nicholas; Ding, Guohua; Singhal, Pravin C

    2003-05-01

    ANG II has been demonstrated to play a role in the progression of tubulointerstial injury. We studied the direct effect of ANG II on apoptosis of cultured rat renal proximal tubular epithelial cells (RPTECs). ANG II promoted RPTEC apoptosis in a dose- and time-dependent manner. This effect of ANG II was attenuated by anti-transforming growth factor (TGF)-beta antibody. Moreover, TGF-beta triggered RPTEC apoptosis in a dose-dependent manner. ANG II also enhanced RPTEC expression of Fas and Fas ligand (FasL); furthermore, anti-FasL antibody attenuated ANG II-induced RPTEC apoptosis. In addition, ANG II increased RPTEC expression of Bax, a cell death protein. Both ANG II type 1 (AT(1)) and type 2 (AT(2)) receptor blockers inhibited ANG II-induced RPTEC apoptosis. SB-202190, an inhibitor of p38 MAPK phosphorylation, and caspase-3 inhibitor also attenuated ANG II-induced RPTEC apoptosis. ANG II enhanced RPTEC heme oxygenase (HO)-1 expression. Interestingly, pretreatment with hemin as well as curcumin (inducers of HO-1) inhibited the ANG II-induced tubular cell apoptosis; conversely, pretreatment with zinc protoporphyrin, an inhibitor of HO-1 expression, promoted the effect of ANG II. These results suggest that ANG II-induced apoptosis is mediated via both AT(1) and AT(2) receptors through the generation of TGF-beta, followed by the transcription of cell death genes such as Fas, FasL, and Bax. Modulation of tubular cell expression of HO-1 has an inverse relationship with the ANG II-induced tubular cell apoptosis.

  10. Curcumin counteracts cisplatin-induced nephrotoxicity by preventing renal tubular cell apoptosis.

    PubMed

    Topcu-Tarladacalisir, Yeter; Sapmaz-Metin, Melike; Karaca, Turan

    2016-11-01

    Curcumin has several biological functions particularly antioxidant and anti-inflammatory. The aims of this study are determination of the protective effects of curcumin on cisplatin-induced renal tubular cell apoptosis and related pathways in kidney. Eighteen male Wistar albino rats were randomly divided into three groups (n = 6): the control, cisplatin (CP), and cisplatin + curcumin (CP + CUR). Acute renal damage was induced by single dose of cisplatin (7.5 mg/kg) injected by intraperitoneally (i.p). The animals of curcumin-treated group were received daily 200 mg/kg curcumin per os (po), starting from 2 days before the injection of cisplatin to the day of sacrifice. Forty-eight hours after cisplatin injection, samples of cardiac blood and kidneys were harvested from the animals. In this study, the major finding is that curcumin treatment ameliorates the following conditions associated with cisplatin-induced nephrotoxicity: (1) the development of kidney injury (histopathology), (2) inflammatory responses [myeloperoxidase (MPO) and tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, IL-10 levels], (3) the degree of lipid peroxidation [malondialdehyde (MDA) level], (4) renal tubular cell apoptosis (active caspase-3) and expression of related proteins [p53, Fas, and Fas ligand (Fas-L)] by immunohistochemistry, (5) renal dysfunction (serum urea and creatinine). In a conclusion, this study suggests that curcumin has antiapoptotic effect against cisplatin nephrotoxicity, in addition to anti-inflammatory and antioxidant properties.

  11. Direct acute tubular damage contributes to Shigatoxin-mediated kidney failure.

    PubMed

    Porubsky, Stefan; Federico, Giuseppina; Müthing, Johannes; Jennemann, Richard; Gretz, Norbert; Büttner, Stefan; Obermüller, Nicholas; Jung, Oliver; Hauser, Ingeborg A; Gröne, Elisabeth; Geiger, Helmut; Gröne, Hermann-Josef; Betz, Christoph

    2014-09-01

    The pathogenesis and therapy of Shigatoxin 2 (Stx2)-mediated kidney failure remain controversial. Our aim was to test whether, during an infection with Stx2-producing E. coli (STEC), Stx2 exerts direct effects on renal tubular epithelium and thereby possibly contributes to acute renal failure. Mice represent a suitable model because they, like humans, express the Stx2-receptor Gb3 in the tubular epithelium but, in contrast to humans, not in glomerular endothelia, and are thus free of glomerular thrombotic microangiopathy (TMA). In wild-type mice, Stx2 caused acute tubular dysfunction with consequent electrolyte disturbance, which was most likely the cause of death. Tubule-specific depletion of Gb3 protected the mice from acute renal failure. In vitro, Stx2 induced secretion of proinflammatory cytokines and apoptosis in human tubular epithelial cells, thus implicating a direct effect of Stx2 on the tubular epithelium. To correlate these results to human disease, kidney biopsies and outcome were analysed in patients with Stx2-associated kidney failure (n = 11, aged 22-44 years). The majority of kidney biopsies showed different stages of an ongoing TMA; however, no glomerular complement activation could be demonstrated. All biopsies, including those without TMA, showed severe acute tubular damage. Due to these findings, patients were treated with supportive therapy without complement-inhibiting antibodies (eculizumab) or immunoadsorption. Despite the severity of the initial disease [creatinine 6.34 (1.31-17.60) mg/dl, lactate dehydrogenase 1944 (753-2792) U/l, platelets 33 (19-124)/nl and haemoglobin 6.2 (5.2-7.8) g/dl; median (range)], all patients were discharged after 33 (range 19-43) days with no neurological symptoms and no dialysis requirement [creatinine 1.39 (range 0.84-2.86) mg/dl]. The creatinine decreased further to 0.90 (range 0.66-1.27) mg/dl after 24 months. Based on these data, one may surmise that acute tubular damage represents a separate

  12. Direct acute tubular damage contributes to Shigatoxin-mediated kidney failure

    PubMed Central

    Porubsky, Stefan; Federico, Giuseppina; Müthing, Johannes; Jennemann, Richard; Gretz, Norbert; Büttner, Stefan; Obermüller, Nicholas; Jung, Oliver; Hauser, Ingeborg A; Gröne, Elisabeth; Geiger, Helmut; Gröne, Hermann-Josef; Betz, Christoph

    2014-01-01

    The pathogenesis and therapy of Shigatoxin 2 (Stx2)-mediated kidney failure remain controversial. Our aim was to test whether, during an infection with Stx2-producing E. coli (STEC), Stx2 exerts direct effects on renal tubular epithelium and thereby possibly contributes to acute renal failure. Mice represent a suitable model because they, like humans, express the Stx2-receptor Gb3 in the tubular epithelium but, in contrast to humans, not in glomerular endothelia, and are thus free of glomerular thrombotic microangiopathy (TMA). In wild-type mice, Stx2 caused acute tubular dysfunction with consequent electrolyte disturbance, which was most likely the cause of death. Tubule-specific depletion of Gb3 protected the mice from acute renal failure. In vitro, Stx2 induced secretion of proinflammatory cytokines and apoptosis in human tubular epithelial cells, thus implicating a direct effect of Stx2 on the tubular epithelium. To correlate these results to human disease, kidney biopsies and outcome were analysed in patients with Stx2-associated kidney failure (n = 11, aged 22–44 years). The majority of kidney biopsies showed different stages of an ongoing TMA; however, no glomerular complement activation could be demonstrated. All biopsies, including those without TMA, showed severe acute tubular damage. Due to these findings, patients were treated with supportive therapy without complement-inhibiting antibodies (eculizumab) or immunoadsorption. Despite the severity of the initial disease [creatinine 6.34 (1.31–17.60) mg/dl, lactate dehydrogenase 1944 (753–2792) U/l, platelets 33 (19–124)/nl and haemoglobin 6.2 (5.2–7.8) g/dl; median (range)], all patients were discharged after 33 (range 19–43) days with no neurological symptoms and no dialysis requirement [creatinine 1.39 (range 0.84–2.86) mg/dl]. The creatinine decreased further to 0.90 (range 0.66–1.27) mg/dl after 24 months. Based on these data, one may surmise that acute tubular damage represents a

  13. Pathogenesis of renal calculi in distal renal tubular acidosis. Possible role of parathyroid hormone.

    PubMed

    Lee, D B; Drinkard, J P; Gonick, H C; Coulson, W F; Cracchiolo, A

    1976-01-01

    Elevated circulating levels of immunoreactive parathyroid hormone (PTH), hypercalciuria and renal calculi were found in 3 patients with distal renal tubular acidosis (RTA). Treatment with alkali resulted in a fall of PTH toward normal and a reduction in urinary calcium, but the frequency of urolithiasis was unchanged. In one patient in whom prolonged follow-up was possible, a subtotal parathyroidectomy was performed. This was followed by virtual cessation of stone formation despite persistence of the acidification defect. This study suggests that RTA may be associated with secondary hyperparathyroidism and that the consequent elevation in PTH may play a contributory role in the pathogenesis of renal calculi.

  14. Micropatterning control of tubular commitment in human adult renal stem cells.

    PubMed

    Sciancalepore, Anna G; Portone, Alberto; Moffa, Maria; Persano, Luana; De Luca, Maria; Paiano, Aurora; Sallustio, Fabio; Schena, Francesco P; Bucci, Cecilia; Pisignano, Dario

    2016-07-01

    The treatment of renal injury by autologous, patient-specific adult stem cells is still an unmet need. Unsolved issues remain the spatial integration of stem cells into damaged areas of the organ, the commitment in the required cell type and the development of improved bioengineered devices. In this respect, biomaterials and architectures have to be specialized to control stem cell differentiation. Here, we perform an extensive study on micropatterned extracellular matrix proteins, which constitute a simple and non-invasive approach to drive the differentiation of adult renal progenitor/stem cells (ARPCs) from human donors. ARPCs are interfaced with fibronectin (FN) micropatterns, in the absence of exogenous chemicals or cellular reprogramming. We obtain the differentiation towards tubular cells of ARPCs cultured in basal medium conditions, the tubular commitment thus being specifically induced by micropatterned substrates. We characterize the stability of the tubular differentiation as well as the induction of a polarized phenotype in micropatterned ARPCs. Thus, the developed cues, driving the functional commitment of ARPCs, offer a route to recreate the microenvironment of the stem cell niche in vitro, that may serve, in perspective, for the development of ARPC-based bioengineered devices.

  15. Changes in free and esterified cholesterol: hallmarks of acute renal tubular injury and acquired cytoresistance.

    PubMed

    Zager, R A; Kalhorn, T F

    2000-09-01

    Acute tubular cell injury is accompanied by plasma membrane phospholipid breakdown. Although cholesterol is a dominant membrane lipid which interdigitates with, and impacts, phospholipid homeostasis, its fate during the induction and recovery phases of acute renal failure (ARF) has remained ill defined. The present study was performed to ascertain whether altered cholesterol expression is a hallmark of evolving tubular damage. Using gas chromatographic analysis, free cholesterol (FC) and esterified cholesterol (CE) were quantified in: 1) isolated mouse proximal tubule segments (PTS) after 30 minutes of hypoxic or oxidant (ferrous ammonium sulfate) injury; 2) cultured proximal tubule (HK-2) cells after 4 or 18 hours of either ATP depletion/Ca(2+) ionophore- or ferrous ammonium sulfate-mediated injury; and 3) in renal cortex 18 hours after induction of glycerol-induced myoglobinuric ARF, a time corresponding to the so-called "acquired cytoresistance" state (ie, resistance to further renal damage). Hypoxic and oxidant injury each induced approximately 33% decrements in CE (but not FC) levels in PTS, corresponding with lethal cell injury ( approximately 50 to 60% LDH release). When comparable CE declines were induced in normal PTS by exogenous cholesterol esterase treatment, proportionate lethal cell injury resulted. During models of slowly evolving HK-2 cell injury, progressive CE increments occurred: these were first noted at 4 hours, and reached approximately 600% by 18 hours. In vivo myoglobinuric ARF produced comparable renal cortical CE (and to a lesser extent FC) increments. Renal CE accumulation strikingly correlated with the severity of ARF (eg, blood urea nitrogen versus CE; r, 0.84). Mevastatin blocked cholesterol accumulation in injured HK-2 cells, indicating de novo synthesis was responsible. Acute tubule injury first lowers, then raises, tubule cholesterol content. Based on previous observations that cholesterol has cytoprotectant properties, the present

  16. Effect of benazepril on the transdifferentiation of renal tubular epithelial cells from diabetic rats

    PubMed Central

    PENG, TAO; WANG, JIE; ZHEN, JUNHUI; HU, ZHAO; YANG, XIANGDONG

    2014-01-01

    The aim of this study was to investigate the effect of benazepril on the transdifferentiation of renal tubular epithelial cells from diabetic rats. Thirty male Sprague-Dawley rats were included in the present study. Eight of the 30 rats were randomly selected and served as the normal control group (N group), while the remaining 22 rats, injected with streptozotocin (STZ), comprised the diabetic rat model. Rats with diabetes were randomly divided into the diabetic (DM group) and benazepril (B group) groups. The total course was conducted over 12 weeks. Blood glucose, body weight, kidney/body weight, 24-h urinary protein, serum creatinine and blood urea nitrogen were measured at the start and end of the study. We observed the tubulointerstitial pathological changes, and applied immunohistochemistry and western blotting to detect the expression of α-smooth muscle actin (α-SMA) in renal tissue. The levels of blood glucose, kidney/body weight, 24-h urinary protein, serum creatinine, blood urea nitrogen and tubulointerstitial damage index (TII) in the DM group were significantly higher than that in the N group (p<0.01). Except for blood glucose and kidney/body weight, the remaining indices were lower in the B group compared with those in the DM group (p<0.01). Immunohistochemical staining results revealed the expression of α-SMA in renal tubular epithelial cells to be significantly higher in the DM and B groups compared with the control (N) group (p<0.01). Western blot analysis revealed that the expression of α-SMA in diabetic renal tissue increased 3.27-fold compared with that of the N group, while the expression of α-SMA in the B group decreased 45% compared with that in the DM group. In conclusion, benazepril significantly reduced the expression of α-SMA in renal tubular epithelial cells obtained from diabetic rats, inhibited the transdifferentiation of renal tubular epithelial cells and played an important role in kidney protection. PMID:24944793

  17. Clinical approach to renal tubular acidosis in adult patients.

    PubMed

    Reddy, P

    2011-03-01

    Renal tubular acidosis (RTA) is a group of disorders observed in patients with normal anion gap metabolic acidosis. There are three major forms of RTA: A proximal (type II) RTA and two types of distal RTAs (type I and type IV). Proximal (type II) RTA originates from the inability to reabsorb bicarbonate normally in the proximal tubule. Type I RTA is associated with inability to excrete the daily acid load and may present with hyperkalaemia or hypokalaemia. The most prominent abnormality in type IV RTA is hyperkalaemia caused by hypoaldosteronism. This article extensively reviews the mechanism of hydrogen ion generation from metabolism of normal diet and various forms of RTA leading to disruptions of normal acid-base handling by the kidneys.

  18. Lethal activity of FADD death domain in renal tubular epithelial cells.

    PubMed

    Justo, P; Sanz, A B; Lorz, C; Egido, J; Ortiz, A

    2006-06-01

    Fas-associated death domain (FADD) is an adaptor protein that is required for the transmission of the death signal from lethal receptors of the tumor necrosis factor superfamily. FADD contains a death domain (DD) and a death effector domain (DED). As death receptors contribute to renal tubular injury and tubular cell FADD increases in acute renal failure, we have studied the function of FADD in tubular epithelium. FADD expression was studied in kidney samples from mice. In order to study the contribution of FADD to renal tubular cell survival, FADD or FADD-DD were overexpressed in murine tubular epithelium. FADD is expressed in renal tubules of the healthy kidney. Both FADD and FADD-DD induce apoptosis in primary cultures of murine tubular epithelium and in the murine cortical tubular cell line. Death induced by FADD-DD has apoptotic morphology, but differs from death receptor-induced apoptosis in that it is not blocked by inhibitors of caspases. Neither an inhibitor of serine proteases nor overexpression of antiapoptotic BclxL prevented cell death. However, the combination of caspase and serine protease inhibition was protective. FADD and FADD-DD overexpression decreased nuclear factor kappa B activity. These data suggest that FADD has a death regulatory function in renal tubular cells that is independent of death receptors. FADD-DD is sufficient to induce apoptosis in these cells. This information is relevant to understanding the role of FADD in tubular injury.

  19. Human embryonic stem cells differentiate into functional renal proximal tubular-like cells.

    PubMed

    Narayanan, Karthikeyan; Schumacher, Karl M; Tasnim, Farah; Kandasamy, Karthikeyan; Schumacher, Annegret; Ni, Ming; Gao, Shujun; Gopalan, Began; Zink, Daniele; Ying, Jackie Y

    2013-04-01

    Renal cells are used in basic research, disease models, tissue engineering, drug screening, and in vitro toxicology. In order to provide a reliable source of human renal cells, we developed a protocol for the differentiation of human embryonic stem cells into renal epithelial cells. The differentiated stem cells expressed markers characteristic of renal proximal tubular cells and their precursors, whereas markers of other renal cell types were not expressed or expressed at low levels. Marker expression patterns of these differentiated stem cells and in vitro cultivated primary human renal proximal tubular cells were comparable. The differentiated stem cells showed morphological and functional characteristics of renal proximal tubular cells, and generated tubular structures in vitro and in vivo. In addition, the differentiated stem cells contributed in organ cultures for the formation of simple epithelia in the kidney cortex. Bioreactor experiments showed that these cells retained their functional characteristics under conditions as applied in bioartificial kidneys. Thus, our results show that human embryonic stem cells can differentiate into renal proximal tubular-like cells. Our approach would provide a source for human renal proximal tubular cells that are not affected by problems associated with immortalized cell lines or primary cells.

  20. Proximal renal tubular injury in rats sub-chronically exposed to low fluoride concentrations

    SciTech Connect

    Cárdenas-González, Mariana C.; Del Razo, Luz M.; Barrera-Chimal, Jonatan; Jacobo-Estrada, Tania; López-Bayghen, Esther; and others

    2013-11-01

    Fluoride is usually found in groundwater at a very wide range of concentration between 0.5 and 25 ppm. At present, few studies have assessed the renal effects of fluoride at environmentally relevant concentrations. Furthermore, most of these studies have used insensitive and nonspecific biomarkers of kidney injury. The aim of this study was to use early and sensitive biomarkers to evaluate kidney injury after fluoride exposure to environmentally relevant concentrations. Recently weaned male Wistar rats were exposed to low (15 ppm) and high (50 ppm) fluoride concentrations in drinking water for a period of 40 days. At the end of the exposure period, kidney injury biomarkers were measured in urine and renal mRNA expression levels were assessed by real time RT-PCR. Our results showed that the urinary kidney injury molecule (Kim-1), clusterin (Clu), osteopontin (OPN) and heat shock protein 72 excretion rate significantly increased in the group exposed to the high fluoride concentration. Accordingly, fluoride exposure increased renal Kim-1, Clu and OPN mRNA expression levels. Moreover, there was a significant dose-dependent increase in urinary β-2-microglobulin and cystatin-C excretion rate. Additionally, a tendency towards a dose dependent increase of tubular damage in the histopathological light microscopy findings confirmed the preferential impact of fluoride on the tubular structure. All of these changes occurred at early stages in which, the renal function was not altered. In conclusion using early and sensitive biomarkers of kidney injury, we were able to found proximal tubular alterations in rats sub-chronically exposed to fluoride. - Highlights: • Exposure to low concentrations of fluoride induced proximal tubular injury • Increase in urinary Kim-1, Clu, OPN and Hsp72 in 50 ppm fluoride-exposed group • Increase in urinary B2M and CysC in 15 and 50 ppm fluoride-exposed groups • Fluoride exposure increased renal Kim, Clu and OPN mRNA expression levels.

  1. Disruption of Renal Tubular Mitochondrial Quality Control by Myo-Inositol Oxygenase in Diabetic Kidney Disease

    PubMed Central

    Zhan, Ming; Usman, Irtaza M.; Sun, Lin

    2015-01-01

    Diabetic kidney disease (DKD) is associated with oxidative stress and mitochondrial injury. Myo-inositol oxygenase (MIOX), a tubular-specific enzyme, modulates redox imbalance and apoptosis in tubular cells in diabetes, but these mechanisms remain unclear. We investigated the role of MIOX in perturbation of mitochondrial quality control, including mitochondrial dynamics and autophagy/mitophagy, under high-glucose (HG) ambience or a diabetic state. HK-2 or LLC-PK1 cells subjected to HG exhibited an upregulation of MIOX accompanied by mitochondrial fragmentation and depolarization, inhibition of autophagy/mitophagy, and altered expression of mitochondrial dynamic and mitophagic proteins. Furthermore, dysfunctional mitochondria accumulated in the cytoplasm, which coincided with increased reactive oxygen species generation, Bax activation, cytochrome C release, and apoptosis. Overexpression of MIOX in LLC-PK1 cells enhanced the effects of HG, whereas MIOX siRNA or d-glucarate, an inhibitor of MIOX, partially reversed these perturbations. Moreover, decreasing the expression of MIOX under HG ambience increased PTEN-induced putative kinase 1 expression and the dependent mitofusin-2–Parkin interaction. In tubules of diabetic mice, increased MIOX expression and mitochondrial fragmentation and defective autophagy were observed. Dietary supplementation of d-glucarate in diabetic mice decreased MIOX expression, attenuated tubular damage, and improved renal functions. Notably, d-glucarate administration also partially attenuated mitochondrial fragmentation, oxidative stress, and apoptosis and restored autophagy/mitophagy in the tubular cells of these mice. These results suggest a novel mechanism linking MIOX to impaired mitochondrial quality control during tubular injury in the pathogenesis of DKD and suggest d-glucarate as a potential therapeutic agent for the amelioration of DKD. PMID:25270067

  2. Tenofovir is associated with increased tubular proteinuria and asymptomatic renal tubular dysfunction in Ghana.

    PubMed

    Chadwick, David R; Sarfo, Fred S; Kirk, Elaine S M; Owusu, Dorcas; Bedu-Addo, George; Parris, Victoria; Owusu, Ann Lorraine; Phillips, Richard

    2015-12-01

    HIV infection is associated with increased risk of renal dysfunction, including tubular dysfunction (TD) related to antiretroviral therapy (ART). Tenofovir disoproxil fumarate (TDF) is becoming available for ART in sub-Saharan Africa, although data on its long-term safety there is limited. We aimed to study the prevalence of HIV-associated renal dysfunction in Ghana and explore associations between proteinuria or TD and potential risk factors, including TDF use. A single-centre cross-sectional observational study of patients taking ART was undertaken. Creatinine clearance (CrCl) was calculated and proteinuria detected with dipsticks. Spot urinary albumin and protein:creatinine ratios (uACR/uPCR) were measured and further evidence of TD (defined as having two or more characteristic features) sought. Logistic regression analysis identified factors associated with proteinuria or TD. In 330 patients, of whom 101 were taking TDF (median 20 months), the prevalence of CrCl < 60 ml/min/1.73 m(2), dipstick proteinuria and TD was 7 %, 37 % and 15 %. Factors associated with proteinuria were baseline CD4-count [aOR 0.86/100 cell increment (95 % CI, 0.74-0.99)] and TDF use [aOR 2.74 (95 % CI, 1.38-5.43)]. The only factor associated with TD was TDF use [aOR 3.43 (95 % CI, 1.10-10.69)]. In a subset with uPCR measurements, uPCRs were significantly higher in patients taking TDF than those on other drugs (10.8 vs. 5.7 mg/mmol, p < 0.001), and urinary albuin:protein ratios significantly lower (0.24 vs. 0.58, p < 0.001). Both proteinuria and TD are common and associated with TDF use in Ghana. Further longitudinal studies to determine whether proteinuria, TD or TDF use are linked to progressive decline in renal function or other adverse outcomes are needed in Africa.

  3. Low molecular weight fucoidan protects renal tubular cells from injury induced by albumin overload

    PubMed Central

    Jia, Yingli; Sun, Yi; Weng, Lin; Li, Yingjie; Zhang, Quanbin; Zhou, Hong; Yang, Baoxue

    2016-01-01

    Albuminuria is a causative and aggravating factor for progressive renal damage in chronic kidney disease (CKD). The aim of this study was to determine if low molecular weight fucoidan (LMWF) could protect renal function and tubular cells from albumin overload caused injury. Treatment with 10 mg/g bovine serum albumin caused renal dysfunction, morphological changes, and overexpression of inflammation and fibrosis associated proteins in 129S2/Sv mice. LMWF (100 mg/kg) protected against kidney injury and renal dysfunction with decreased blood creatinine by 34% and urea nitrogen by 25%, increased creatinine clearance by 48%, and decreased significantly urinary albumin concentration. In vitro proximal tubule epithelial cell (NRK-52E) model showed that LMWF dose-dependently inhibited overexpression of proinflammatory and profibrotic factors, oxidative stress and apoptosis caused by albumin overload. These experimental results indicate that LMWF protects against albumin overload caused renal injury by inhibiting inflammation, fibrosis, oxidative stress and apoptosis, which suggests that LMWF could be a promising candidate drug for preventing CKD. PMID:27545472

  4. Renal tubular acidosis is highly prevalent in critically ill patients.

    PubMed

    Brunner, Richard; Drolz, Andreas; Scherzer, Thomas-Matthias; Staufer, Katharina; Fuhrmann, Valentin; Zauner, Christian; Holzinger, Ulrike; Schneeweiß, Bruno

    2015-04-06

    Hyperchloremic acidosis is frequent in critically ill patients. Renal tubular acidosis (RTA) may contribute to acidemia in the state of hyperchloremic acidosis, but the prevalence of RTA has never been studied in critically ill patients. Therefore, we aimed to investigate the prevalence, type, and possible risk factors of RTA in critically ill patients using a physical-chemical approach. This prospective, observational trial was conducted in a medical ICU of a university hospital. One hundred consecutive critically ill patients at the age ≥18, expected to stay in the ICU for ≥24 h, with the clinical necessity for a urinary catheter and the absence of anuria were included. Base excess (BE) subset calculation based on a physical-chemical approach on the first 7 days after ICU admission was used to compare the effects of free water, chloride, albumin, and unmeasured anions on the standard base excess. Calculation of the urine osmolal gap (UOG)--as an approximate measure of the unmeasured urine cation NH4(+)--served as determinate between renal and extrarenal bicarbonate loss in the state of hyperchloremic acidosis. During the first week of ICU stay 43 of the patients presented with hyperchloremic acidosis on one or more days represented as pronounced negative BEChloride. In 31 patients hyperchloremic acidosis was associated with RTA characterized by a UOG ≤150 mosmol/kg in combination with preserved renal function. However, in 26 of the 31 patients with RTA metabolic acidosis was neutralized by other acid-base disturbances leading to a normal arterial pH. RTA is highly prevalent in critically ill patients with hyperchloremic acidosis, whereas it is often neutralized by the simultaneous occurrence of other acid-base disturbances. Clinicaltrials.gov NCT02392091. Registered 17 March 2015.

  5. Role of CDK5/cyclin complexes in ischemia-induced death and survival of renal tubular cells.

    PubMed

    Guevara, Tatiana; Sancho, Mónica; Pérez-Payá, Enrique; Orzáez, Mar

    2014-01-01

    Ischemia reperfusion processes induce damage in renal tubules and compromise the viability of kidney transplants. Understanding the molecular events responsible for tubule damage and recovery would help to develop new strategies for organ preservation. CDK5 has been traditionally considered a neuronal kinase with dual roles in cell death and survival. Here, we demonstrate that CDK5 and their regulators p35/p25 and cyclin I are also expressed in renal tubular cells. We show that treatment with CDK inhibitors promotes the formation of pro-survival CDK5/cyclin I complexes and enhances cell survival upon an ischemia reperfusion pro-apoptotic insult. These findings support the benefit of treating with CDK inhibitors for renal preservation, assisting renal tubule protection.

  6. Osteomalacia complicating renal tubular acidosis in association with Sjogren's syndrome.

    PubMed

    El Ati, Zohra; Fatma, Lilia Ben; Boulahya, Ghada; Rais, Lamia; Krid, Madiha; Smaoui, Wided; Maiz, Hedi Ben; Beji, Soumaya; Zouaghi, Karim; Moussa, Fatma Ben

    2014-09-01

    Renal involvement in Sjogren's syndrome (SS) is not uncommon and may precede other complaints. Tubulointerstitial nephritis is the most common renal disease in SS and may lead to renal tubular acidosis (RTA), which in turn may cause osteomalacia. Nevertheless, osteomalacia rarely occurs as the first manifestation of a renal tubule disorder due to SS. We herewith describe a 43-year-old woman who was admitted to our hospital for weakness, lumbago and inability to walk. X-ray of the long bones showed extensive demineralization of the bones. Laboratory investigations revealed chronic kidney disease with serum creatinine of 2.3 mg/dL and creatinine clearance of 40 mL/min, hypokalemia (3.2 mmol/L), hypophosphatemia (0.4 mmol/L), hypocalcemia (2.14 mmol/L) and hyperchloremic metabolic acidosis (chlorine: 114 mmol/L; alkaline reserve: 14 mmol/L). The serum alkaline phosphatase levels were elevated. The serum levels of 25-hydroxyvitamin D and 1,25-dihydroxy vitamin D were low and borderline low, respectively, and the parathyroid hormone level was 70 pg/L. Urinalysis showed inappropriate alkaline urine (urinary PH: 7), glycosuria with normal blood glucose, phosphaturia and uricosuria. These values indicated the presence of both distal and proximal RTA. Our patient reported dryness of the mouth and eyes and Schirmer's test showed xerophthalmia. An accessory salivary gland biopsy showed changes corresponding to stage IV of Chisholm and Masson score. Kidney biopsy showed diffuse and severe tubulo-interstitial nephritis with dense lymphoplasmocyte infiltrates. Sicca syndrome and renal interstitial infiltrates indicated SS as the underlying cause of the RTA and osteomalacia. The patient received alkalinization, vitamin D (Sterogyl ®), calcium supplements and steroids in an initial dose of 1 mg/kg/day, tapered to 10 mg daily. The prognosis was favorable and the serum creatinine level was 1.7 mg/dL, calcium was 2.2 mmol/L and serum phosphate was 0.9 mmol/L.

  7. Reduced Renal Methylarginine Metabolism Protects against Progressive Kidney Damage

    PubMed Central

    Caplin, Ben; Boruc, Olga; Bruce-Cobbold, Claire; Cutillas, Pedro; Dormann, Dirk; Faull, Peter; Grossman, Rebecca C.; Khadayate, Sanjay; Mas, Valeria R.; Nitsch, Dorothea D.; Wang, Zhen; Norman, Jill T.; Wilcox, Christopher S.; Wheeler, David C.; Leiper, James

    2015-01-01

    Nitric oxide (NO) production is diminished in many patients with cardiovascular and renal disease. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthesis, and elevated plasma levels of ADMA are associated with poor outcomes. Dimethylarginine dimethylaminohydrolase-1 (DDAH1) is a methylarginine-metabolizing enzyme that reduces ADMA levels. We reported previously that a DDAH1 gene variant associated with increased renal DDAH1 mRNA transcription and lower plasma ADMA levels, but counterintuitively, a steeper rate of renal function decline. Here, we test the hypothesis that reduced renal-specific ADMA metabolism protects against progressive renal damage. Renal DDAH1 is expressed predominately within the proximal tubule. A novel proximal tubule–specific Ddah1 knockout (Ddah1PT−/−) mouse demonstrated tubular cell accumulation of ADMA and lower NO concentrations, but unaltered plasma ADMA concentrations. Ddah1PT−/− mice were protected from reduced kidney tissue mass, collagen deposition, and profibrotic cytokine expression in two independent renal injury models: folate nephropathy and unilateral ureteric obstruction. Furthermore, a study of two independent kidney transplant cohorts revealed higher levels of human renal allograft methylarginine-metabolizing enzyme gene expression associated with steeper function decline. We also report an association among DDAH1 expression, NO activity, and uromodulin expression supported by data from both animal and human studies, raising the possibility that kidney DDAH1 expression exacerbates renal injury through uromodulin-related mechanisms. Together, these data demonstrate that reduced renal tubular ADMA metabolism protects against progressive kidney function decline. Thus, circulating ADMA may be an imprecise marker of renal methylarginine metabolism, and therapeutic ADMA reduction may even be deleterious to kidney function. PMID:25855779

  8. Ameliorative effect of green tea against contrast-induced renal tubular cell injury.

    PubMed

    Nasri, Hamid; Hajian, Shabnam; Ahmadi, Ali; Baradaran, Azar; Kohi, Golnoosh; Nasri, Parto; Rafieian-Kopaei, Mahmoud

    2015-11-01

    Reactive oxygen species are a mediator of kidney damage by contrast media, and green tea is a potent-free radical scavenger. This study was designed to examine whether green tea could protect against the nephrotoxicity induced by contrast media. Forty rats were randomly divided into 4 groups. Group 1 was control; group 2 received contrast medium (intravenous iodixanol, 10 mL/kg, as a single dose); group 3 received contrast medium and then green tea extract for 3 days (10 mg/kg/d, intraperitoneal); and group 4 first received green tea and then contrast medium. Histological changes (degeneration, vacuolization of tubular renal cells, dilatation of tubular lumen, and presence of debris in the lumens) were assessed and recorded as scores from zero to 4. The sum of scores were used as the overal renal injury level. Groups 3 and 4 with green tea treatment had significantly higher overall scores than the control group, but significantly lower scores than group 2 with contrast medium only. A similar trend was seen for dilatation and degeneration levels. Vacuolization level was not significantly lower in the green tea groups as compared to the contrast medium group. Debris level was not significantly lower in group 3 than group 2. The differences were not significant between groups 3 and 4.   Conclusions. We observed beneficial effect of green tea against nephrotoxicity of contrast media. Green tea extract may offer an inexpensive and nontoxic intervention strategy in patients with a risk for nephrotoxicity with contrast media.

  9. Renal function damage in 131 cases of urogenital tuberculosis.

    PubMed

    Wisnia, L G; Kukolj, S; Lopez de Santa Maria, J; Camuzzi, F

    1978-05-01

    The functional sequelae of 131 patients with urogenital tuberculosis were examined. At the time of diagnosis, more than half of the patients already suffered from global renal failure which was moderate in 42.7 per cent and severe in 15.5 per cent. We believe that the primary functional damage occurs at the medullary level with tubular and interstitial involvement. Indeed, the red phenol test for postglomerular blood flow was altered in a higher proportion than was the creatinine clearance (67.9 per cent). The maximum concentrating ability was altered even more frequently (84 per cent). When we compared various glomerular filtration levels with the grade of alteration of the maximum ability concentration test, we also saw clearly that the alteration of the tubular interstitial medullar function dominated the alteration of the glomerular global function. This proves at a functional level the predominantly medullary localization of the lesion in renal tuberculosis.

  10. Development of bioartificial renal tubule devices with lifespan-extended human renal proximal tubular epithelial cells.

    PubMed

    Sanechika, Noriyuki; Sawada, Kaichiro; Usui, Yukio; Hanai, Kazuya; Kakuta, Takatoshi; Suzuki, Hajime; Kanai, Genta; Fujimura, Satoshi; Yokoyama, Tun Aung; Fukagawa, Masafumi; Terachi, Toshiro; Saito, Akira

    2011-09-01

    The bioartificial renal tubule device is a cell therapy system for renal failure. The major obstacle in the development of the bioartificial renal tubule device is the obtainment of a large number of viable renal tubule cells to seed on the inner surface of hollow fibers. Although our previous studies had used a transformed cell line, they may be dangerous for clinical uses. Therefore, different approaches to amplify renal proximal tubular epithelial cells (RPTEC) in culture without oncogenes, vectors and carcinogens have been required. The limitation of the replicative lifespan of human RPTEC, which is ∼12 population doublings (PDs), was extended by invalidating messenger RNA of cell cycle-related genes with antisense oligonucleotide or small interfering RNA (siRNA). Periodic transfection of siRNA to a tumor suppressor p53 or a cyclin-dependent kinase inhibitor p16(INK4a) extended the lifespan by 33 and 63 PDs, respectively, in 3 months of culture. The siRNA-mediated lifespan extension was controllable because cell division ceased within 2 weeks after the transfection was discontinued. Expressions of γ-glutamyltransferase 1 and glucose transporter 1 were recovered in siRNA-transfected RPTEC cultured on porous membranes. Bioartificial renal tubule devices (0.8 m(2)) constructed with these cells showed reabsorption of water (122.3 ± 4.2 mL/30 min), sodium (18.1 ± 0.7 mEq/30 min) and glucose (121.7 ± 4.4 mg/30 min) after 1 week of circulation. Furthermore, β2-microglobulin and pentosidine were metabolized by RPTEC in mini-devices (65 cm(2)) within 48 h of circulation. These approaches enabled us to yield a high enough number of RPTEC for construction of bioartificial renal tubule devices repeatedly. Lifespan-extended RPTEC could recover their specific characteristics by culturing on porous membranes, and bioartificial renal tubule devices constructed with these cells showed good performances of reabsorption and metabolism. A large number of human renal tubular

  11. Hypokalemic quadriparesis and rhabdomyolysis as a rare presentation of distal renal tubular acidosis

    PubMed Central

    Ahmad Bhat, Manzoor; Ahmad Laway, Bashir; Mustafa, Farhat; Shafi Kuchay, Mohammad; Mubarik, Idrees; Ahmad Palla, Nazir

    2014-01-01

    Distal renal tubular acidosis is a syndrome of abnormal urine acidification and is characterized by hyperchloremic metabolic acidosis, hypokalemia, hypercalciurea, nephrocalcinosis and nephrolithiasis. Despite the presence of persistent hypokalemia, acute muscular paralysis is rarely encountered in males. Here, we will report an eighteen year old male patient who presented with flaccid quadriparesis and was subsequently found to have rhabdomyolysis, severe short stature, skeletal deformities and primary distal renal tubular acidosis. PMID:25250276

  12. Renal tubular function in patients with beta-thalassaemia major in Zahedan, southeast Iran.

    PubMed

    Sadeghi-Bojd, S; Hashemi, M; Karimi, M

    2008-05-01

    In patients with beta-thalassaemia major, impaired biosynthesis of the beta-globin leads to accumulation of unpaired alpha-globin chain. Shortened red cell lifespan and iron overload cause functional and physiological abnormalities in various organ systems. Thus, in patients with beta-thalassaemia major, the most important cause of mortality and morbidity is organ failure due to deposits of iron. The aim of this study is to investigate renal tubular and glomerular functions in patients with beta-thalassaemia major. 166 subjects with beta-thalassaemia major (96 male, 70 female) were enrolled in the study. Fasting blood and 24-hour urine samples were obtained for haematological and biochemical analyses. Patients with beta-thalassaemia major showed significant signs of renal tubulopathy, such as hypercalciuria (12.9 percent), proteinuria (8.6 percent), phosphaturia (9.2 percent), magnesiumuria (8.6 percent), hyperuricosuria (38 percent) and excretion of beta-2 microglobin (13.5 percent). We found that 95.1 percent of patients had iron overload (ferritin more than 1,000 ng/ml). The determination of biochemical indices of renal function might help prevention of serious kidney damage before any clinical symptom is observed. Beta-thalassaemia patients present multiple renal abnormalities which may be due to iron overload. We suggest the appropriate chelation therapy and regular monitoring of the status of iron overload.

  13. Increased oxidative DNA damage seen in renal biopsies adjacent stones in patients with nephrolithiasis.

    PubMed

    Kittikowit, Wipawee; Waiwijit, Uraiwan; Boonla, Chanchai; Ruangvejvorachai, Preecha; Pimratana, Chaowat; Predanon, Chagkrapan; Ratchanon, Supoj; Tosukhowong, Piyaratana

    2014-10-01

    Urinary excretion of 8-hydroxydeoxyguanosine (8-OHdG), a marker of oxidative DNA damage, is significantly higher in nephrolithiasis patients than in healthy individuals, indicating that these patients have higher degree of oxidative stress. In the present study, we investigated 8-OHdG expression in renal biopsies of patients with nephrolithiasis and in renal tubular cells (HK-2 cells) exposed to calcium oxalate monohydrate (COM). We performed immunohistochemical staining for 8-OHdG in renal biopsies adjacent stones obtained from 28 patients with nephrolithiasis. Controls were noncancerous renal tissues from nephrectomies of patients with renal cancer. 8-OHdG was overexpressed in the nucleus of renal tubular cells in patients with nephrolithiasis compared with controls. Only one nephrolithiasis biopsy was negative for 8-OHdG, whereas in 19 cases 8-OHdG was highly expressed. The level of expression of 8-OHdG among patients with calcium oxalate (mostly mixed with calcium phosphate) and uric acid stones was not significantly different. Increased leukocyte infiltration was observed in renal tissues from patients with nephrolithiasis. Exposure of HK-2 cells to COM caused increased intracellular reactive oxygen species and nuclear expression of 8-OHdG. To our knowledge, this is the first report of increased 8-OHdG expression in renal tubular cells of patients with nephrolithiasis. In vitro, COM crystals were capable of inducing oxidative damage of DNA in the proximal renal tubular cells.

  14. TRAP1 ameliorates renal tubulointerstitial fibrosis in mice with unilateral ureteral obstruction by protecting renal tubular epithelial cell mitochondria.

    PubMed

    Chen, Jun-Feng; Wu, Qi-Shun; Xie, Yu-Xian; Si, Bo-Lin; Yang, Ping-Ping; Wang, Wen-Yan; Hua, Qin; He, Qing

    2017-10-01

    Mitochondrial dysfunction causes renal tubular epithelial cell injury and promotes cell apoptosis and renal tubulointerstitial fibrosis (TIF) progression. TNF receptor-associated protein 1 (TRAP1) is a molecular chaperone protein that is localized in mitochondria. It plays an important role in cell apoptosis; however, its functional mechanism in TIF remains unclear. In this study, we observed the effects of TRAP1 in renal tubular epithelial cell mitochondria in mice with unilateral ureteral obstruction and its function in cell apoptosis and TIF. Results show that TRAP1 could protect the mitochondrial structure in renal tubular epithelial cells; maintain the levels of mitochondrial membrane potential, ATP, and mitochondrial DNA copy number; inhibit reactive oxygen species production; stabilize the expression of the mitochondrial inner membrane protein mitofilin; reduce renal tubular epithelial cell apoptosis; and inhibit TIF. These results provide new theoretical foundations for additional understanding of the antifibrotic mechanism of TRAP1 in the kidney.-Chen, J.-F., Wu, Q.-S., Xie, Y.-X., Si, B.-L., Yang, P.-P., Wang, W.-Y., Hua, Q., He, Q. TRAP1 ameliorates renal tubulointerstitial fibrosis in mice with unilateral ureteral obstruction by protecting renal tubular epithelial cell mitochondria. © FASEB.

  15. Protective Role of Apelin Against Cyclosporine-Induced Renal Tubular Injury in Rats.

    PubMed

    Kim, J S; Yang, J W; Han, B G; Kwon, H J; Kim, J H; Choi, S O

    Cyclosporine (CsA) usually reduces glomerular filtration rate (GFR) but also can induce tubular injury without resulting in GFR reduction. Apelin is an endogenous ligand for the apelin receptor and has diverse physiologic roles related to hemodynamic or metabolic processes. We investigated the renoprotective role of apelin against CsA-induced tubular toxicity in rats. Rats were given CsA (15 mg/kg/day) and/or apelin-13 (15 μg/kg/day) for 7 days via subcutaneous injection. We performed serum and urinary assays of creatinine and neutrophil gelatinase-associated lipocalin (NGAL) to estimate renal injury and performed Western blotting for endothelial nitric oxide synthase and nuclear factor of activated T-cell cytoplasmic 1 (NFATc1) to document the underlying mechanism. The CsA-treated group showed increased urinary creatinine excretion, polyuria, and renal glycosuria without GFR reduction, suggesting adequate CsA-induced renal tubular injury. Urinary NGAL excretion also increased significantly in the CsA group. Conversely, apelin attenuated CsA-induced tubular injury and had no effect on urinary NGAL excretion. In histopathologic examination, the apelin-treated group had lower tubulo-interstitial injury scores compared with those in the CsA group. Regarding the effects of apelin, our results indicate that apelin provides protection against CsA-induced tubular injury by activating nitric oxide and/or the NFATc1 pathway. Notably, we also found that CsA inhibits renal glucose reabsorption by reducing Na(+)-K(+) ATPase expression and that apelin reverses reduced renal glucose reabsorption by CsA in tubular cells. Our study demonstrates the renoprotective effect of apelin against CsA-induced renal tubular toxicity and provides novel insights into the effects of CsA and apelin on renal tubular cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Downregulation of renal tubular Wnt/β-catenin signaling by Dickkopf-3 induces tubular cell death in proteinuric nephropathy

    PubMed Central

    Wong, D W L; Yiu, W H; Wu, H J; Li, R X; Liu, Y; Chan, K W; Leung, J C K; Chan, L Y Y; Lai, K N; Tang, S C W

    2016-01-01

    Studies on the role of Wnt/β-catenin signaling in different forms of kidney disease have yielded discrepant results. Here, we report the biphasic change of renal β-catenin expression in mice with overload proteinuria in which β-catenin was upregulated at the early stage (4 weeks after disease induction) but abrogated at the late phase (8 weeks). Acute albuminuria was observed at 1 week after bovine serum albumin injection, followed by partial remission at 4 weeks that coincided with overexpression of renal tubular β-catenin. Interestingly, a rebound in albuminuria at 8 weeks was accompanied by downregulated tubular β-catenin expression and heightened tubular apoptosis. In addition, there was an inverse relationship between Dickkopf-3 (Dkk-3) and renal tubular β-catenin expression at these time points. In vitro, a similar trend in β-catenin expression was observed in human kidney-2 (HK-2) cells with acute (upregulation) and prolonged (downregulation) exposure to albumin. Induction of a proapoptotic phenotype by albumin was significantly enhanced by silencing β-catenin in HK-2 cells. Finally, Dkk-3 expression and secretion was increased after prolonged exposure to albumin, leading to the suppression of intracellular β-catenin signaling pathway. The effect of Dkk-3 on β-catenin signaling was confirmed by incubation with exogenous Dkk-3 in HK-2 cells. Taken together, these data suggest that downregulation of tubular β-catenin signaling induced by Dkk-3 has a detrimental role in chronic proteinuria, partially through the increase in apoptosis. PMID:27010856

  17. Expression of cleaved caspase-3 in renal tubular cells in Plasmodium falciparum malaria patients.

    PubMed

    Wichapoon, Benjamas; Punsawad, Chuchard; Viriyavejakul, Parnpen

    2017-01-01

    In Plasmodium falciparum malaria, the clinical manifestation of acute kidney injury (AKI) is commonly associated with acute tubular necrosis (ATN) in the kidney tissues. Renal tubular cells often exhibit various degrees of cloudy swelling, cell degeneration, and frank necrosis. To study individual cell death, this study evaluates the degree of renal tubular necrosis in association with apoptosis in malarial kidneys. Kidney tissues from P. falciparum malaria with AKI (10 cases), and without AKI (10 cases) were evaluated for tubular pathology. Normal kidney tissues from 10 cases served as controls. Tubular necrosis was assessed quantitatively in kidney tissues infected with P. falciparum malaria, based on histopathological evaluation. In addition, the occurrence of apoptosis was investigated using cleaved caspase-3 marker. Correlation between tubular necrosis and apoptosis was analyzed. Tubular necrosis was found to be highest in P. falciparum malaria patients with AKI (36.44% ± 3.21), compared to non-AKI (15.88% ± 1.63) and control groups (2.58% ± 0.39) (all p < 0.001). In the AKI group, the distal tubules showed a significantly higher degree of tubular necrosis than the proximal tubules (p = 0.021) and collecting tubules (p = 0.033). Tubular necrosis was significantly correlated with the level of serum creatinine (r = 0.596, p = 0.006), and the occurrence of apoptosis (r = 0.681, p = 0.001). In malarial AKI, the process of apoptosis occurs in ATN. © 2016 Asian Pacific Society of Nephrology.

  18. HIV-1 Vpr activates the DNA damage response in renal tubule epithelial cells.

    PubMed

    Rosenstiel, Paul E; Chan, Justin; Snyder, Alexander; Planelles, Vicente; D'Agati, Vivette D; Klotman, Paul E; Klotman, Mary E

    2009-09-24

    HIV-associated nephropathy (HIVAN) is a major cause of HIV-related morbidity and mortality. Pathogenesis involves direct infection of the glomerular and tubular epithelial cells leading to characteristic disorder. Recently, we have shown that HIV-1 Vpr causes hypertrophy, hyperploidy, and apoptosis. Here, we report that Vpr activates the DNA damage response resulting in the observed renal phenotype. Renal sections from the HIVAN transgenic mouse model and human biopsies both show an abundant DNA damage response.

  19. Role of the renal sympathetic nerves in renal sodium/potassium handling and renal damage in spontaneously hypertensive rats

    PubMed Central

    Li, Jianling; He, Qiaoling; Wu, Weifeng; Li, Qingjie; Huang, Rongjie; Pan, Xiaofeng; Lai, Wenying

    2016-01-01

    Renal sympathetic nerve activity has an important role in renal disease-associated hypertension and in the modulation of fluid homeostasis. In the present study, changes in renal function and renal sodium/potassium handling were investigated in groups of 12-week-old male, spontaneously hypertensive rats with renal denervation (RDNX group) or sham denervation (sham group). The RDNX group excreted significantly more sodium than the sham group during the 2-week observation period (P<0.05). Following bilateral renal denervation, the fractional lithium excretion was elevated in the RDNX group compared with the sham group, but no significant effect was observed of renal denervation on the fractional distal reabsorption rate of sodium or the fractional excretion of potassium. Furthermore, the glomerular injury score and the wall-to-lumen ratio of the interlobular artery were significantly lower in the RDNX group than in the sham group (P<0.05). In conclusion, the present study indicates an involvement of the renal sympathetic nerves in the regulation of renal tubular sodium reabsorption in spontaneously hypertensive rats and in the renal damage associated with hypertension. PMID:27698757

  20. Decreased renal uptake of (99m)Tc-DMSA in patients with tubular proteinuria.

    PubMed

    Lee, Beom Hee; Lee, So Hee; Choi, Hyun Jin; Kang, Hee Gyung; Oh, So Won; Lee, Dong Soo; Ha, Il Soo; Choi, Yong; Cheong, Hae Il

    2009-11-01

    Although technetium-99m-dimercaptosuccinic acid ((99m)Tc-DMSA) renal scans are widely used to evaluate renal tubular mass function, the mechanism by which renal uptake of DMSA occurs is still the subject of debate. Patients with various proximal tubular disorders show markedly decreased renal DMSA uptake, even when there is normal creatinine clearance. We measured the renal uptake of (99m)Tc-DMSA 3 h after its injection in 13 patients with Dent disease or Lowe syndrome, both of which are typical proximal tubular disorders with defective megalin and cubilin-mediated endocytosis. Serial images of three patients were also obtained at 0.5, 1, 2 and 3 h post-injection. The correlations between renal uptake of (99m)Tc-DMSA and creatinine clearance and the degrees of acidemia and tubular proteinuria were then evaluated. The renal uptake of (99m)Tc-DMSA was markedly decreased in all patients, and the decreased uptake was detected in all serial images. In contrast, bladder radioactivity was higher than normal in all of the serial images when compared to renal radioactivity. Additionally, the uptake of (99m)Tc-DMSA was inversely proportional to the amount of urine beta(2)-microglobulin. These results strongly suggest that DMSA is filtered in the glomeruli and subsequently undergoes megalin- and cubilin-mediated endocytosis in the proximal tubules.

  1. HSP72 attenuates renal tubular cell apoptosis and interstitial fibrosis in obstructive nephropathy

    PubMed Central

    Mao, Haiping; Li, Zhilian; Zhou, Yi; Li, Zhijian; Zhuang, Shougang; An, Xin; Zhang, Baiyu; Chen, Wei; Nie, Jing; Wang, Zhiyong; Borkan, Steven C.; Wang, Yihan; Yu, Xueqing

    2008-01-01

    Although heat shock protein 72 kDa (HSP72) protects tubular epithelium from a variety of acute insults, its role in chronic renal injury and fibrosis is poorly characterized. In this study, we tested the hypothesis that HSP72 reduces apoptosis and epithelial-to-mesenchymal transition (EMT), important contributors to tubular cell injury in vitro and in vivo. In rats, orally administered geranylgeranylacetone (GGA), an agent that selectively induces HSP72, markedly reduced both apoptosis and cell proliferation in tubular epithelium and decreased both interstitial fibroblast accumulation and collagen I deposition after unilateral ureteric obstruction, a model of chronic renal tubulointerstitial fibrosis and dysfunction. In cultured renal NRK52E cells, exposure to TGF-β1 induced EMT and apoptosis, major causes of renal fibrosis and tubular atrophy, respectively. Exposure to a pan-caspase inhibitor (ZVAD-FMK) prevented TGF-β1-induced apoptosis but did not reduce EMT. In contrast, selective HSP72 expression in vitro inhibited EMT caused by TGF-β1 as indicated by preserving the E-cadherin expression level and α-smooth muscle actin induction. Small interfering RNA directed against HSP72 blocked the cytoprotective effects of HSP72 overexpression on EMT in TGF-β1-exposed cells. Taken together, our data indicate that HSP72 ameliorates renal tubulointerstitial fibrosis in obstructive nephropathy by inhibiting both renal tubular epithelial cell apoptosis and EMT. PMID:18417540

  2. Suppressive effects of iron on TGF-beta1 production by renal proximal tubular epithelial cells.

    PubMed

    Horino, Taro; Ito, Hiroyuki; Yamaguchi, Takuya; Furihata, Mutsuo; Hashimoto, Kozo

    2005-01-01

    TGF-beta1, which is one of the profibrogenic cytokines, is considered essential for both the tubulointerstitial fibrosis found in chronic kidney diseases and the repair of tissue damage in acute renal injury. Iron plays an important part in inflammatory damage since it supplies cytotoxic hydroxyl radicals. The aim of the present study was to examine the direct effects of iron on TGF-beta1 production and the expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, by human renal proximal tubular epithelial cells (RPTEC). Using human RPTEC, TGF-beta1 expression was studied by immunohistochemical staining, ELISA and RNase protection assays. 8-OHdG expression was evaluated by immunohistochemical staining. Ferric iron suppressed both TGF-beta1 secretion and mRNA expression, and enhanced 8-OHdG expression in RPTEC in a dose-dependent manner. Desferrioxamine, an iron chelator, eliminated the suppressive effect of ferric citrate on TGF-beta1 production. The results suggest that iron may delay the repair of kidney injury during the acute inflammatory phase via a reduction in TGF-beta1 production by RPTEC. Iron chelation may therefore be a useful strategy in the treatment of inflammatory kidney diseases.

  3. Effect of astragalus injection on renal tubular epithelial transdifferentiation in type 2 diabetic mice.

    PubMed

    Yi, Yue-E; Li, Shu-Yu; Nie, Yan-Na; Jia, De-Xian; Zhang, Zhi-Hui; Wang, Yan-Fei; Wang, Qian

    2016-07-16

    Astragalus injection is used by practitioners of traditional Chinese medicine to treat diabetic nephropathy (DN). The current study was conducted to determine the effect of astragalus on tubular epithelial transdifferentiation during the progression of DN in KKAy mice, as well as to investigate the molecular mechanism underlying this effect. Diabetic, 14-week-old, male KKAy mice were randomly divided into a model group and an astragalus treatment group, while age-matched male C57BL/6 J mice were selected as controls. The treatment group received daily intraperitoneal injections of astragalus (0.03 mL/10 g per day), while the model group received injections of an equal volume of saline. Mice were euthanized after 24 weeks. Serum samples were obtained from the animals in each group for blood glucose measurement. Kidney tissue samples were used for morphometric studies. The mRNA and protein expression levels of transforming growth factor beta 1 (TGF-β1), transforming growth factor beta receptor 1 (TGFβ-R1), alpha smooth muscle actin (α-SMA), and E-cadherin were evaluated using real-time polymerase chain reaction (PCR) and western blotting. Astragalus significantly reduced blood glucose levels; inhibited morphological changes in the kidneys of KKAy mice; reduced mRNA and protein expression levels of TGF-β1, TGFβ-R1, and α-SMA; and increased E-cadherin expression. Tubular epithelial transdifferentiation plays an important role in the development of DN in diabetic mice. Administration of astragalus likely prevents or mitigates DN by suppressing tubular epithelial transdifferentiation, protecting KKAy mice from renal damage.

  4. Genomic damage in chronic renal failure--potential therapeutic interventions.

    PubMed

    Stopper, Helga; Schupp, Nicole; Klassen, André; Sebekova, Katarina; Heidland, August

    2005-01-01

    In end-stage renal failure, genomic damage is enhanced. This has been shown both in the predialysis and dialysis phase by various biomarkers, such as micronuclei frequency and single cell gel electrophoresis in lymphocytes as well as with 8-hydroxy-2'-deoxyguanosine in leukocytes. There are also data about mitochondrial DNA deletions and chromosomal abnormalities. Genomic damage may be induced by a multitude of toxic factors and mutagens, in particular via enhanced generation of reactive oxygen species. In in vitro studies, incubation of tubular cells with various AGEs (carboxymethyllysine-BSA, AGE-BSA, and methylglyoxal-BSA) and angiotensin II resulted in a marked DNA damage. Coincubation with various antioxidants as well as the angiotensin II receptor blocker, candesartan, suppressed the toxic action. Moreover, an improved uremic state by daily hemodialysis ameliorated the genomic damage in lymphocytes, as compared to patients on conventional hemodialysis.

  5. Genetics Home Reference: renal tubular acidosis with deafness

    MedlinePlus

    ... to softening and weakening of the bones , called rickets in children and osteomalacia in adults. This bone ... tubular acidosis and sensorineural hearing loss. Clin Genet. 2013 Mar;83(3):274-8. doi: 10.1111/ ...

  6. Local synthesis of interferon-alpha in lupus nephritis is associated with type I interferons signature and LMP7 induction in renal tubular epithelial cells.

    PubMed

    Castellano, Giuseppe; Cafiero, Cesira; Divella, Chiara; Sallustio, Fabio; Gigante, Margherita; Pontrelli, Paola; De Palma, Giuseppe; Rossini, Michele; Grandaliano, Giuseppe; Gesualdo, Loreto

    2015-03-22

    Type I interferons are pivotal in the activation of autoimmune response in systemic lupus erythematous. However, the pathogenic role of interferon-alpha in patients affected by lupus nephritis remains uncertain. The aim of our study was to investigate the presence of a specific interferon signature in lupus nephritis and the effects of interferon-alpha at renal level. We performed immunohistochemical analysis for MXA-protein and in situ hybridization to detect interferon-alpha signature and production in human lupus nephritis. Through microarray studies, we analyzed the gene expression profile of renal tubular epithelial cells, stimulated with interferon-alpha. We validated microarray results through real-time polymerase chain reaction, flow cytometry on renal tubular epithelial cells, and through immunohistochemical analysis and confocal microscopy on renal biopsies. Type I interferons signature was characterized by MXA-specific staining in renal tubular epithelial cells; in addition, in situ hybridization showed that renal tubular epithelial cells were the major producers of interferon-alpha, indicating a potential autocrine effect. Whole-genome expression profile showed interferon-alpha induced up-regulation of genes involved in innate immunity, protein ubiquitination and switching to immunoproteasome. In accordance with the in vitro data, class IV lupus nephritis showed up-regulation of the immunoproteasome subunit LMP7 in tubular epithelial cells associated with type I interferon signature. Our data indicate that type I interferons might have a pathogenic role in lupus nephritis characterized by an autocrine effect of interferon-alpha on renal tubular epithelial cells. Therefore we hypothesize that inhibition of type I interferons might represent a therapeutic target to prevent tubulo-interstitial damage in patients with lupus nephritis.

  7. Human anion exchanger1 mutations and distal renal tubular acidosis.

    PubMed

    Yenchitsomanus, Pa-thai

    2003-09-01

    The human anion exchanger 1 (AE1 or SLC4A1) gene encodes anion exchanger 1 (or band 3) protein in erythrocytes and in alpha-intercalated cells of the kidney. Thus, AE1 mutations show pleiotrophic effects resulting in two distinct and seemingly unrelated defects, an erythrocyte abnormality and distal renal tubular acidosis (dRTA). Southeast Asian ovalocytosis (SAO), a well-known red blood cell (RBC) defect, which is widespread in Southeast Asian regions, is caused by AE1 mutation due to a deletion of 27 base pairs in codons 400-408 (delta400-408) leading to an in-frame 9 amino-acid loss in the protein. Co-existence of SAO and dRTA is usually not seen in the same individual. However, the two conditions can co-exist as the result of compound heterozygosities between delta400-408 and other mutations. The reported genotypes include delta400-408/G701D, delta400-408/R602H, delta400-408/deltaV850, and delta400-408/A858D. The presence of dRTA, with or without RBC abnormalities, may occur from homozygous or compound heterozygous conditions of recessive AE1 mutations (eg G701D/G701D, V488M/V488M, deltaV850/deltaV850, deltaV850/A858D, G701D/S773P) or heterozygous dominant AE1 mutations (eg R598H, R589C, R589S, S613F, R901X). Codon 589 of this gene seems to be a 'mutational hot-spot' since repeated mutations at this codon occurring in different ethnic groups and at least two de novo (R589H and R589C) mutations have been observed. Therefore, AE1 mutations can result in both recessive and dominant dRTA, possibly depending on the position of the amino acid change in the protein. As several mutant AE1 proteins still maintain a significant anion transport function but are defective in targeting to the cell surface, impaired intracellular trafficking of the mutant AE1 is an important molecular mechanism involved in the pathogenesis of dRTA associated with AE1 mutations.

  8. Correction of renal tubular acidosis in carbonic anhydrase II-deficient mice with gene therapy.

    PubMed Central

    Lai, L W; Chan, D M; Erickson, R P; Hsu, S J; Lien, Y H

    1998-01-01

    Carbonic anhydrase II (CAII) deficiency in humans is associated with a syndrome of renal tubular acidosis, osteopetrosis, and cerebral calcification. A strain of mice of CAII deficiency due to a point mutation also manifests renal tubular acidosis. We report here that retrograde injection of cationic liposome complexed with a CAII chimeric gene, using a cytomegalovirus (CMV) promoter/enhancer as an expression cassette to drive human CAII cDNA, into the renal pelvis of CAII-deficient mice results in expression of CAII in the kidney. The levels of both the CAII gene and its corresponding mRNA were highest by day 3 after treatment, diminishing thereafter, but remaining detectable by 1 mo. After gene therapy, CAII-deficient mice restored the ability to acidify urine after oral administration of ammonium chloride. The ability to acidify urine was maintained at 3 wk after gene therapy, and was eventually lost by 6 wk. Immunohistochemistry studies using anti-CAII antibodies showed that CAII was expressed in tubular cells of the outer medulla and corticomedullary junction. The gene therapy was not associated with nephrotoxicity as assessed by blood urea nitrogen levels and renal histology. To our knowledge, this is the first successful gene therapy of a genetic renal disease. Our results demonstrate the potential of gene therapy as a novel treatment for hereditary renal tubular defects. PMID:9525974

  9. Endoplasmic reticulum stress and its effects on renal tubular cells apoptosis in ischemic acute kidney injury.

    PubMed

    Xu, Yan; Guo, Min; Jiang, Wei; Dong, Hui; Han, Yafei; An, Xiao-Fei; Zhang, Jisheng

    2016-06-01

    Ischemia is the most frequent cause of acute kidney injury (AKI), which is characterized by apoptosis of renal tubular cell. A common result of ischemia in AKI is dysfunction of endoplasmic reticulum (ER), which causes the protein-folding capacity to lag behind the protein-folding load. The abundance of misfolded proteins stressed the ER and results in induction of the unfolded protein response (UPR). While the UPR is an adaptive response, over time it can result in apoptosis when cells are unable to recover quickly. Recent research suggests that ER stress is a major factor in renal tubular cell apoptosis resulting from ischemic AKI. Thus, ER stress may be an important new progression factor in the pathology of ischemic AKI. In this article, we review UPR signaling, describe pathology and pathophysiology mechanisms of ischemic AKI, and highlight the dual function of ER stress on renal tubular cell apoptosis.

  10. Renal tubular epithelial cell prorenin receptor regulates blood pressure and sodium transport.

    PubMed

    Ramkumar, Nirupama; Stuart, Deborah; Mironova, Elena; Bugay, Vladislav; Wang, Shuping; Abraham, Nikita; Ichihara, Atsuhiro; Stockand, James D; Kohan, Donald E

    2016-07-01

    The physiological significance of the renal tubular prorenin receptor (PRR) has been difficult to elucidate due to developmental abnormalities associated with global or renal-specific PRR knockout (KO). We recently developed an inducible renal tubule-wide PRR KO using the Pax8/LC1 transgenes and demonstrated that disruption of renal tubular PRR at 1 mo of age caused no renal histological abnormalities. Here, we examined the role of renal tubular PRR in blood pressure (BP) regulation and Na(+) excretion and investigated the signaling mechanisms by which PRR regulates Na(+) balance. No detectable differences in BP were observed between control and PRR KO mice fed normal- or low-Na(+) diets. However, compared with controls, PRR KO mice had elevated plasma renin concentration and lower cumulative Na(+) balance with normal- and low-Na(+) intake. PRR KO mice had an attenuated hypertensive response and reduced Na(+) retention following angiotensin II (ANG II) infusion. Furthermore, PRR KO mice had significantly lower epithelial Na(+) channel (ENaC-α) expression. Treatment with mouse prorenin increased, while PRR antagonism decreased, ENaC activity in isolated split-open collecting ducts (CD). The prorenin effect was prevented by protein kinase A and Akt inhibition, but unaffected by blockade of AT1, ERK1/2, or p38 MAPK pathways. Taken together, these data indicate that renal tubular PRR, likely via direct prorenin/renin stimulation of PKA/Akt-dependent pathways, stimulates CD ENaC activity. Absence of renal tubular PRR promotes Na(+) wasting and reduces the hypertensive response to ANG II.

  11. p-Cresol mediates autophagic cell death in renal proximal tubular cells.

    PubMed

    Lin, Hsin-Hung; Huang, Chiu-Ching; Lin, Tze-Yi; Lin, Ching-Yuang

    2015-04-02

    Higher serum level of p-cresol (PC) in chronic kidney disease (CKD) patients has been linked with CKD progression. The toxic effect of PC on diverse cells has been reported by prior studies, except for renal tubular cells. Both autophagy and apoptosis contribute to renal tubular cell death, yet evidence of its response to PC is limited and their crosstalk is still unclear. Autophagy is an important cellular process involved in toxin-induced cell death. Renal tubular cell death in tubular injury is thought to be one of the key events causing the progression of CKD. Thus, we treated rat (NRK-52E) and human (HRPTEC) renal proximal tubular cells (RPTC) with PC and found the cell proliferation was significantly decreased. Cell apoptosis was significantly increased and accompanied with the activation of autophagy as evidenced by increases in LC3-II, beclin 1 and Atg 4. We also found an increase of p62 by c-Jun activation. p62 accumulation could mediate the activation of caspase 8-dependent cell apoptosis. Conversely, knockdown of p62 by siRNA of p62 had the opposite effect by arresting LC3-II accumulation and promoting increasing cell viability. We conclude that PC triggered autophagic RPTC death via JNK-mediated p62 accumulation and then activated caspase 8-dependent cell death pathway. PC can be considered as one of the key events causing progression of CKD, which might affect drug disposition in CKD cases.

  12. Cellular Uptake and Localization of Polymyxins in Renal Tubular Cells Using Rationally Designed Fluorescent Probes

    PubMed Central

    Yun, Bo; Azad, Mohammad A. K.; Nowell, Cameron J.; Nation, Roger L.; Thompson, Philip E.; Roberts, Kade D.

    2015-01-01

    Polymyxins are cyclic lipopeptide antibiotics that serve as a last line of defense against Gram-negative bacterial superbugs. However, the extensive accumulation of polymyxins in renal tubular cells can lead to nephrotoxicity, which is the major dose-limiting factor in clinical use. In order to gain further insights into the mechanism of polymyxin-induced nephrotoxicity, we have rationally designed novel fluorescent polymyxin probes to examine the localization of polymyxins in rat renal tubular (NRK-52E) cells. Our design strategy focused on incorporating a dansyl fluorophore at the hydrophobic centers of the polymyxin core structure. To this end, four novel regioselectively labeled monodansylated polymyxin B probes (MIPS-9541, MIPS-9542, MIPS-9543, and MIPS-9544) were designed, synthesized, and screened for their antimicrobial activities and apoptotic effects against rat kidney proximal tubular cells. On the basis of the assessment of antimicrobial activities, cellular uptake, and apoptotic effects on renal tubular cells, incorporation of a dansyl fluorophore at either position 6 or 7 (MIPS-9543 and MIPS-9544, respectively) of the polymyxin core structure appears to be an appropriate strategy for generating representative fluorescent polymyxin probes to be utilized in intracellular imaging and mechanistic studies. Furthermore, confocal imaging experiments utilizing these probes showed evidence of partial colocalization of the polymyxins with both the endoplasmic reticulum and mitochondria in rat renal tubular cells. Our results highlight the value of these new fluorescent polymyxin probes and provide further insights into the mechanism of polymyxin-induced nephrotoxicity. PMID:26392495

  13. Tumor-promoting phorbol esters effect alkalinization of canine renal proximal tubular cells

    SciTech Connect

    Mellas, J.; Hammerman, M.R.

    1986-03-01

    We have demonstrated the presence of specific receptors for tumor-promoting phorbol esters in the plasma membrane of the canine renal proximal tubular cell. These compounds affect proximal tubular metabolism in vitro. For example, we have shown that they inhibit gluconeogenesis in canine renal proximal tubular segments. Tumor-promoting phorbol esters have been shown to effect alkalinization of non-renal cells, by enhancing Na/sup +/-H/sup +/ exchange across the plasma membrane. To determine whether the actions of tumor-promoting phorbol esters in proximal tubular segments might be mediated by a similar process, we incubated suspensions of segments from dog kidney with these compounds and measured changes in intracellular pH using (/sup 14/C)-5,5-dimethoxazoladine-2-4-dione (DMO) and flow dialysis. Incubation of segments with phorbol 12,13 dibutyrate, but not inactive phorbol ester, 4 ..gamma.. phorbol, effected alkalinization of cells within the segments in a concentration-dependent manner. Alkalinization was dependent upon the presence of extracellular (Na/sup +/) > intracellular (Na/sup +/), was prevented by amiloride and was demonstrable in the presence of SITS. Our findings suggest that tumor-promoting esters stimulate the Na/sup +/-H/sup +/ exchanger known to be present in the brush border membrane of the renal proximal tubular cell. It is possible that the stimulation reflects a mechanism by which phorbol esters affect metabolic processes in these cells.

  14. Renal tubular dysfunction in children living in the Aral Sea Region

    PubMed Central

    Kaneko, K; Chiba, M; Hashizume, M; Kunii, O; Sasaki, S; Shimoda, T; Yamashiro, Y; Caypil, W; Dauletbaev, D

    2003-01-01

    Background: The Aral Sea region is a natural area seriously polluted by human activities. Recent surveillance revealed the increased prevalence of diverse chronic diseases in children. Aims: To investigate the function of renal tubules, which are most at risk of damage as a result of heavy metal intoxication, in children of the Aral Sea region. Methods: A group of 205 children living in Kazalinsk, close to the Aral Sea, and a group of 187 children living in Zhanakorgan, far from the Aral Sea, were examined by means of random urine samples. Both urinary N-acetyl-ß-D-glucosaminidase (NAG; U/mmol Cr) and ß2 microglobulin (BMG; µg/mmol Cr) were calculated for each subject. Results: Mean urinary NAG and BMG were both significantly higher in Kazalinsk than in Zhanakorgan (NAG: 0.77 (0.58) and 0.62 (0.37) U/mmol Cr; BMG: 41.8 (54.8) and 22.5 (20.4) µg/mmol Cr, respectively; mean (SD), p < 0.01). The number of children with abnormal values of NAG (>1.5 U/mmol Cr) was significantly more prevalent in Kazalinsk than in Zhanakorgan (7.9% and 2.6%, respectively, p < 0.05). Conclusion: Renal tubular function of children around the Aral Sea region is profoundly impaired. This should be taken into account when considering the health problems of this area. PMID:14612357

  15. Renal tubular dysfunction in children living in the Aral Sea Region.

    PubMed

    Kaneko, K; Chiba, M; Hashizume, M; Kunii, O; Sasaki, S; Shimoda, T; Yamashiro, Y; Caypil, W; Dauletbaev, D

    2003-11-01

    The Aral Sea region is a natural area seriously polluted by human activities. Recent surveillance revealed the increased prevalence of diverse chronic diseases in children. To investigate the function of renal tubules, which are most at risk of damage as a result of heavy metal intoxication, in children of the Aral Sea region. A group of 205 children living in Kazalinsk, close to the Aral Sea, and a group of 187 children living in Zhanakorgan, far from the Aral Sea, were examined by means of random urine samples. Both urinary N-acetyl-beta-D-glucosaminidase (NAG; U/mmol Cr) and beta2 microglobulin (BMG; microg/mmol Cr) were calculated for each subject. Mean urinary NAG and BMG were both significantly higher in Kazalinsk than in Zhanakorgan (NAG: 0.77 (0.58) and 0.62 (0.37) U/mmol Cr; BMG: 41.8 (54.8) and 22.5 (20.4) microg/mmol Cr, respectively; mean (SD), p < 0.01). The number of children with abnormal values of NAG (>1.5 U/mmol Cr) was significantly more prevalent in Kazalinsk than in Zhanakorgan (7.9% and 2.6%, respectively, p < 0.05). Renal tubular function of children around the Aral Sea region is profoundly impaired. This should be taken into account when considering the health problems of this area.

  16. Renal Cortical Lactate Dehydrogenase: A Useful, Accurate, Quantitative Marker of In Vivo Tubular Injury and Acute Renal Failure

    PubMed Central

    Zager, Richard A.; Johnson, Ali C. M.; Becker, Kirsten

    2013-01-01

    Studies of experimental acute kidney injury (AKI) are critically dependent on having precise methods for assessing the extent of tubular cell death. However, the most widely used techniques either provide indirect assessments (e.g., BUN, creatinine), suffer from the need for semi-quantitative grading (renal histology), or reflect the status of residual viable, not the number of lost, renal tubular cells (e.g., NGAL content). Lactate dehydrogenase (LDH) release is a highly reliable test for assessing degrees of in vitro cell death. However, its utility as an in vivo AKI marker has not been defined. Towards this end, CD-1 mice were subjected to graded renal ischemia (0, 15, 22, 30, 40, or 60 min) or to nephrotoxic (glycerol; maleate) AKI. Sham operated mice, or mice with AKI in the absence of acute tubular necrosis (ureteral obstruction; endotoxemia), served as negative controls. Renal cortical LDH or NGAL levels were assayed 2 or 24 hrs later. Ischemic, glycerol, and maleate-induced AKI were each associated with striking, steep, inverse correlations (r, −0.89) between renal injury severity and renal LDH content. With severe AKI, >65% LDH declines were observed. Corresponding prompt plasma and urinary LDH increases were observed. These observations, coupled with the maintenance of normal cortical LDH mRNA levels, indicated the renal LDH efflux, not decreased LDH synthesis, caused the falling cortical LDH levels. Renal LDH content was well maintained with sham surgery, ureteral obstruction or endotoxemic AKI. In contrast to LDH, renal cortical NGAL levels did not correlate with AKI severity. In sum, the above results indicate that renal cortical LDH assay is a highly accurate quantitative technique for gauging the extent of experimental acute ischemic and toxic renal injury. That it avoids the limitations of more traditional AKI markers implies great potential utility in experimental studies that require precise quantitation of tubule cell death. PMID:23825563

  17. Rhein Inhibits Autophagy in Rat Renal Tubular Cells by Regulation of AMPK/mTOR Signaling

    PubMed Central

    Tu, Yue; Gu, Liubao; Chen, Diping; Wu, Wei; Liu, Hong; Hu, Hao; Wan, Yigang; Sun, Wei

    2017-01-01

    Rhubarb and its bioactive component rhein are frequently used for the treatment of chronic kidney diseases (CKD) in eastern Asia countries. However, the potential therapeutic mechanism remains unclear. Autophagy plays an important role in CKD. However, there were some important related issues that remained unresolved in the role of autophagy in CKD and treatment by rhubarb and rhein. We designed a number of experiments to examine whether rhubarb may reduce renal fibrosis and autophagy in rats with adenine (Ade)-induced renal tubular injury, and whether rhein could affect autophagic pathways in rat renal tubular cells. We found that, autophagic activation accompanied with renal fibrosis in rats with Ade-induced renal tubular injury, and both autophagy and renal fibrosis were attenuated by rhubarb. In addition, we observed that rhein could inhibit autophagy through regulating the key molecules in the AMPK-dependent mTOR signaling pathways, as well as the Erk and p38 MAPKs signaling pathways. These findings may partly explain the therapeutic mechanisms of rhubarb and rhein in treating CKD patients in clinic, and further suggest that targeting autophagy and related signaling pathways may provide new strategies for the treatment of renal fibrosis in CKD. PMID:28252052

  18. Renal tubular epithelium-targeted peroxisome proliferator-activated receptor-γ maintains the epithelial phenotype and antagonizes renal fibrogenesis

    PubMed Central

    Ding, Guixia; Xu, Ying; Bai, Mi; Zhang, Yue; Jia, Zhanjun; Huang, Songming; Zhang, Aihua

    2016-01-01

    Accumulating evidence suggests that loss of the renal tubular epithelial phenotype plays an important role in the pathogenesis of renal tubulointerstitial fibrosis. Systemic activation of peroxisome proliferator-activated receptor γ (PPAR-γ) has been shown to be protective against renal fibrosis, although the mechanisms are poorly understood. The present study aimed to define the role of renal tubular epithelium-targeted PPAR-γ in protection of the epithelial phenotype and the antagonism of renal fibrosis and to define the underlying mechanisms. In response to TGF-β1 challenge, PPAR-γ expression and activity in the renal proximal tubule epithelial cells (RPTECs) were significantly reduced, and the reduction was accompanied by decreased E-cadherin and elevated α-SMA, indicating a loss of the epithelial phenotype. Oxidative stress induced by TGF-β1 was shown to be attributed to the alteration of the epithelial phenotype and PPAR-γ inhibition. Activation of PPAR-γ by its agonists of rosiglitazone and 15d-PGJ2 or genetic overexpression of PPAR-γ prevented the loss of the epithelial phenotype induced by TGF-β1 in line with the inhibition of oxidative stress. To explore the role of PPAR-γ in renal tubular epithelial in antagonizing fibrogenesis, PPAR-γ was specifically deleted from RPTECs in mice. Following unilateral ureteral obstruction, the fibrosis was markedly deteriorated in mice with PPAR-γ invalidation in RPTECs. Treatment with rosiglitazone attenuated tubulointerstitial fibrosis and epithelial phenotype transition in WT but not proximal tubule PPAR-γ KO mice. Taken together, these findings identified an important role of renal tubular epithelium-targeted PPAR-γ in maintaining the normal epithelial phenotype and opposing fibrogenesis, possibly via antagonizing oxidative stress. PMID:27602490

  19. Tubular Dickkopf-3 promotes the development of renal atrophy and fibrosis

    PubMed Central

    Federico, Giuseppina; Meister, Michael; Mathow, Daniel; Heine, Gunnar H.; Moldenhauer, Gerhard; Popovic, Zoran V.; Nordström, Viola; Kopp-Schneider, Annette; Hielscher, Thomas; Nelson, Peter J.; Schaefer, Franz; Porubsky, Stefan; Fliser, Danilo; Arnold, Bernd; Gröne, Hermann-Josef

    2016-01-01

    Renal tubular atrophy and interstitial fibrosis are common hallmarks of etiologically different progressive chronic kidney diseases (CKD) that eventually result in organ failure. Even though these pathological manifestations constitute a major public health problem, diagnostic tests, as well as therapeutic options, are currently limited. Members of the dickkopf (DKK) family, DKK1 and -2, have been associated with inhibition of Wnt signaling and organ fibrosis. Here, we identify DKK3 as a stress-induced, tubular epithelia–derived, secreted glycoprotein that mediates kidney fibrosis. Genetic as well as antibody-mediated abrogation of DKK3 led to reduced tubular atrophy and decreased interstitial matrix accumulation in two mouse models of renal fibrosis. This was facilitated by an amplified, antifibrogenic, inflammatory T cell response and diminished canonical Wnt/β-catenin signaling in stressed tubular epithelial cells. Moreover, in humans, urinary DKK3 levels specifically correlated with the extent of tubular atrophy and interstitial fibrosis in different glomerular and tubulointerstitial diseases. In summary, our data suggest that DKK3 constitutes an immunosuppressive and a profibrotic epithelial protein that might serve as a potential therapeutic target and diagnostic marker in renal fibrosis. PMID:27699213

  20. Tubular Dickkopf-3 promotes the development of renal atrophy and fibrosis.

    PubMed

    Federico, Giuseppina; Meister, Michael; Mathow, Daniel; Heine, Gunnar H; Moldenhauer, Gerhard; Popovic, Zoran V; Nordström, Viola; Kopp-Schneider, Annette; Hielscher, Thomas; Nelson, Peter J; Schaefer, Franz; Porubsky, Stefan; Fliser, Danilo; Arnold, Bernd; Gröne, Hermann-Josef

    2016-01-21

    Renal tubular atrophy and interstitial fibrosis are common hallmarks of etiologically different progressive chronic kidney diseases (CKD) that eventually result in organ failure. Even though these pathological manifestations constitute a major public health problem, diagnostic tests, as well as therapeutic options, are currently limited. Members of the dickkopf (DKK) family, DKK1 and -2, have been associated with inhibition of Wnt signaling and organ fibrosis. Here, we identify DKK3 as a stress-induced, tubular epithelia-derived, secreted glycoprotein that mediates kidney fibrosis. Genetic as well as antibody-mediated abrogation of DKK3 led to reduced tubular atrophy and decreased interstitial matrix accumulation in two mouse models of renal fibrosis. This was facilitated by an amplified, antifibrogenic, inflammatory T cell response and diminished canonical Wnt/β-catenin signaling in stressed tubular epithelial cells. Moreover, in humans, urinary DKK3 levels specifically correlated with the extent of tubular atrophy and interstitial fibrosis in different glomerular and tubulointerstitial diseases. In summary, our data suggest that DKK3 constitutes an immunosuppressive and a profibrotic epithelial protein that might serve as a potential therapeutic target and diagnostic marker in renal fibrosis.

  1. Type IV renal tubular acidosis and spironolactone therapy in the elderly.

    PubMed Central

    O'Connell, J. E.; Colledge, N. R.

    1993-01-01

    Spironolactone therapy is a well-known cause of hyperkalaemia, but in susceptible patient, it may also be associated with metabolic acidosis. We report a case of severe renal tubular acidosis (Type IV) with life-threatening hyperkalaemia caused by spironolactone, and discuss the mechanisms by which this may occur. PMID:8290440

  2. Trimethoprim related Hyperkalaemia in a patient with Renal Tubular Acidosis Type 4.

    PubMed

    Patel, M C

    2009-01-01

    Hyperkalaemia is a common, treatable, medical emergency, often with an iatrogenic cause. This case illustrates the vulnerability of patients with pre-existing renal tubular acidosis type 4 to medications that further inhibit renin-aldosterone action. The case also illustrates the danger of keeping entirely separate case notes between different hospital disciplines.

  3. Renal phenotypic investigations of megalin-deficient patients: novel insights into tubular proteinuria and albumin filtration.

    PubMed

    Storm, Tina; Tranebjærg, Lisbeth; Frykholm, Carina; Birn, Henrik; Verroust, Pierre J; Nevéus, Tryggve; Sundelin, Birgitta; Hertz, Jens Michael; Holmström, Gerd; Ericson, Katharina; Christensen, Erik I; Nielsen, Rikke

    2013-03-01

    The reabsorption of filtered plasma proteins, hormones and vitamins by the renal proximal tubules is vital for body homeostasis. Studies of megalin-deficient mice suggest that the large multi-ligand endocytic receptor megalin plays an essential role in this process. In humans, dysfunctional megalin causes the extremely rare Donnai-Barrow/Facio-Oculo-Acustico-Renal (DB/FOAR) syndrome characterized by a characteristic and multifaceted phenotype including low-molecular-weight proteinuria. In this study, we examined the role of megalin for tubular protein reabsorption in humans through analysis of proximal tubular function in megalin-deficient patients. Direct sequencing of the megalin-encoding gene (LRP2) was performed in a family in which three children presented with classical DB/FOAR manifestations. Renal consequences of megalin deficiency were investigated through immunohistochemical analyses of renal biopsy material and immunoblotting of urine samples. In the patients, a characteristic urinary protein profile with increased urinary excretion of vitamin D-binding protein, retinol-binding protein and albumin was associated with absence of, or reduced, proximal tubular endocytic uptake as shown by renal immunohistochemistry. In the absence of tubular uptake, urinary albumin excretion was in the micro-albuminuric range suggesting that limited amounts of albumin are filtered in human glomeruli. This study demonstrated that megalin plays an essential role for human proximal tubular protein reabsorption and suggests that only limited amounts of albumin is normally filtered in the human glomeruli. Finally, we propose that the characteristic urinary protein profile of DB/FOAR patients may be utilized as a diagnostic marker of megalin dysfunction.

  4. Stem Cell Conditioned Culture Media Attenuated Albumin-Induced Epithelial– Mesenchymal Transition in Renal Tubular Cells

    PubMed Central

    Hu, Junping; Zhu, Qing; Li, Pin-Lan; Wang, Weili; Yi, Fan; Li, Ningjun

    2015-01-01

    Background Proteinuria-induced epithelial-mesenchymal transition (EMT) plays an important role in progressive renal tubulointerstitial fibrosis in chronic renal disease. Stem cell therapy has been used for different diseases. Stem cell conditioned culture media (SCM) exhibits similar beneficial effects as stem cell therapy. The present study tested the hypothesis that SCM inhibits albumin-induced EMT in cultured renal tubular cells. Methods Rat renal tubular cells were treated with/without albumin (20 μmg/ml) plus SCM or control cell media (CCM). EMT markers and inflammatory factors were measured by Western blot and fluorescent images. Results Albumin induced EMT as shown by significant decreases in levels of epithelial marker E-cadherin, increases in mesenchymal markers fibroblast-specific protein 1 and α-smooth muscle actin, and elevations in collagen I. SCM inhibited all these changes. Meanwhile, albumin induced NF-κB translocation from cytosol into nucleus and that SCM blocked the nuclear translocation of NF-κB. Albumin also increased the levels of pro-inflammatory factor monocyte chemoattractant protein-1 (MCP)-1 by nearly 30 fold compared with control. SCM almost abolished albumin-induced increase of MCP-1. Conclusion These results suggest that SCM attenuated albumin-induced EMT in renal tubular cells via inhibiting activation of inflammatory factors, which may serve as a new therapeutic approach for chronic kidney diseases. PMID:25832005

  5. Persistent activation of autophagy in kidney tubular cells promotes renal interstitial fibrosis during unilateral ureteral obstruction

    PubMed Central

    Livingston, Man J.; Ding, Han-Fei; Huang, Shuang; Hill, Joseph A.; Yin, Xiao-Ming; Dong, Zheng

    2016-01-01

    ABSTRACT Renal fibrosis is the final, common pathway of end-stage renal disease. Whether and how autophagy contributes to renal fibrosis remains unclear. Here we first detected persistent autophagy in kidney proximal tubules in the renal fibrosis model of unilateral ureteral obstruction (UUO) in mice. UUO-associated fibrosis was suppressed by pharmacological inhibitors of autophagy and also by kidney proximal tubule-specific knockout of autophagy-related 7 (PT-Atg7 KO). Consistently, proliferation and activation of fibroblasts, as indicated by the expression of ACTA2/α-smooth muscle actin and VIM (vimentin), was inhibited in PT-Atg7 KO mice, so was the accumulation of extracellular matrix components including FN1 (fibronectin 1) and collagen fibrils. Tubular atrophy, apoptosis, nephron loss, and interstitial macrophage infiltration were all inhibited in these mice. Moreover, these mice showed a specific suppression of the expression of a profibrotic factor FGF2 (fibroblast growth factor 2). In vitro, TGFB1 (transforming growth factor β 1) induced autophagy, apoptosis, and FN1 accumulation in primary proximal tubular cells. Inhibition of autophagy suppressed FN1 accumulation and apoptosis, while enhancement of autophagy increased TGFB1-induced-cell death. These results suggest that persistent activation of autophagy in kidney proximal tubules promotes renal interstitial fibrosis during UUO. The profibrotic function of autophagy is related to the regulation on tubular cell death, interstitial inflammation, and the production of profibrotic factors. PMID:27123926

  6. Ghrelin Protects against Renal Damages Induced by Angiotensin-II via an Antioxidative Stress Mechanism in Mice

    PubMed Central

    Fujimura, Keiko; Wakino, Shu; Minakuchi, Hitoshi; Hasegawa, Kazuhiro; Hosoya, Koji; Komatsu, Motoaki; Kaneko, Yuka; Shinozuka, Keisuke; Washida, Naoki; Kanda, Takeshi; Tokuyama, Hirobumi; Hayashi, Koichi; Itoh, Hiroshi

    2014-01-01

    We explored the renal protective effects by a gut peptide, Ghrelin. Daily peritoneal injection with Ghrelin ameliorated renal damages in continuously angiotensin II (AngII)-infused C57BL/6 mice as assessed by urinary excretion of protein and renal tubular markers. AngII-induced increase in reactive oxygen species (ROS) levels and senescent changes were attenuated by Ghrelin. Ghrelin also inhibited AngII-induced upregulations of transforming growth factor-β (TGF-β) and plasminogen activator inhibitor-1 (PAI-1), ameliorating renal fibrotic changes. These effects were accompanied by concomitant increase in mitochondria uncoupling protein, UCP2 as well as in a key regulator of mitochondria biosynthesis, PGC1α. In renal proximal cell line, HK-2 cells, Ghrelin reduced mitochondria membrane potential and mitochondria-derived ROS. The transfection of UCP2 siRNA abolished the decrease in mitochondria-derived ROS by Ghrelin. Ghrelin ameliorated AngII-induced renal tubular cell senescent changes and AngII-induced TGF-β and PAI-1 expressions. Finally, Ghrelin receptor, growth hormone secretagogue receptor (GHSR)-null mice exhibited an increase in tubular damages, renal ROS levels, renal senescent changes and fibrosis complicated with renal dysfunction. GHSR-null mice harbored elongated mitochondria in the proximal tubules. In conclusion, Ghrelin suppressed AngII-induced renal damages through its UCP2 dependent anti-oxidative stress effect and mitochondria maintenance. Ghrelin/GHSR pathway played an important role in the maintenance of ROS levels in the kidney. PMID:24747517

  7. Proximal renal tubular acidosis in pregnancy. A case report and literature review.

    PubMed

    Firmin, C J; Kruger, T F; Davids, R

    2007-01-01

    Renal tubular acidosis is usually associated with chronic renal conditions and is rarely encountered in pregnancy. It may be inherited causing osteomalacia and rickets in children or acquired following autoimmune diseases or following exposure to nephrotoxic agents. It is known to worsen during pregnancy and if left untreated may cause maternal and foetal morbidity or death. We report a 28-year-old woman, gravida 3 para 2, who presented at 30 weeks gestation with lethargy, weakness and generalized myalgia. Investigation revealed severe hypokalaemia and a systemic metabolic acidosis due to proximal renal tubular acidosis. Her previous pregnancies were both complicated by foetal losses at term. Following prompt correction of her electrolyte disturbance and metabolic acidosis, she went on to deliver a healthy female infant at term. Regular evaluation up to 1 year post-partum revealed mild persistence of her hypokalaemia. At 1 year, the infant showed no signs of the disorder and is growing normally.

  8. Angiotensin II natriuresis and antinatriuresis: role of renal artery pressure, renal hemodynamics, and tubular reabsorption.

    PubMed

    Olsen, M E; Hall, J E; Montani, J P; Guyton, A C

    1985-01-01

    The aim of this study was to determine the role of changes in renal artery pressure (RAP), renal hemodynamics, and tubular reabsorption in mediating the natriuretic and antinatriuretic actions of angiotensin II (AII). In anesthetized dogs, endogenous AII formation was blocked with SQ-14225 and AII was infused i.v. at rates of 5-1215 ng/kg/min while RAP was either servo-controlled at the normal level or permitted to increase. When RAP was servo-controlled to prevent a rise i RAP, AII infusion at all rates from 5-1215 ng/kg/min decreased urinary sodium excretion (UNaV) and fractional sodium excretion (FENa), while increasing fractional reabsorption of lithium (FRLi), an index of proximal tubule fractional sodium reabsorption and distal fractional sodium reabsorption (FRDNa): When RAP was permitted to increase, AII infusion rates up to 45 ng/kg/min decreased UNaV, and FENa, while increasing FRLi and FRDNa. However, at 135 ng/kg/min and above, UNaV and FENa increased while FRLi and FRDNa decreased when RAP was allowed to rise, even though RBF and FF were not substantially different from the values observed when RAP was servo-controlled. Filtered sodium load was slightly higher when RAP was permitted to increase during AII infusion, compared to the dogs in which RAP was servo-controlled, although the differences were not statistically significant. Thus, even very large doses of AII cause antinatriuresis when RAP was prevented from increasing. The natriuretic effect of high dose of AII is caused by increased RAP which decreases fractional sodium reabsorption in proximal and distal tubules and causes slight increases in sodium delivery to the tubules.

  9. Expression of a functional asialoglycoprotein receptor in human renal proximal tubular epithelial cells.

    PubMed

    Seow, Ying-ying T; Tan, Michelle G K; Woo, Keng Thye

    2002-07-01

    The asialoglycoprotein receptor (ASGPR) is a C lectin which binds and endocytoses serum glycoproteins. In humans, the ASGPR is shown mainly to occur in hepatocytes, but does occur extrahepatically in thyroid, in small and large intestines, and in the testis. In the kidney, there has been evidence both for and against its existence in mesangial cells. Standard light microscopy examination of renal tissue stained with an antibody against the ASGPR was performed. The mRNA expression for the ASGPR H1 and H2 subunits in primary human renal proximal tubular epithelial cells (RPTEC), in the human proximal tubular epithelial cell line HK2, and in human renal cortex was investigated using reverse-transcribed nested polymerase chain reaction. ASGPR protein expression as well as ligand binding and uptake were also examined using confocal microscopy and flow cytometry (fluorescence-activated cell sorting). Light microscopy of paraffin renal biopsy sections stained with a polyclonal antibody against the ASGPR showed proximal tubular epithelial cell staining of the cytoplasm and particularly in the basolateral region. Renal cortex and RPTEC specifically have mRNA for both H1 and H2 subunits of the ASGPR, but HK2 only expresses mRNA for H1. Using a monoclonal antibody, the presence of the ASGPR in RPTEC was shown by fluorescence-activated cell sorting and immunofluorescent staining. Specific binding and uptake of fluorescein isothiocyanate labelled asialofetuin which is a specific ASGPR ligand was also demonstrated in RPTEC. Primary renal proximal tubular epithelial cells have a functional ASGPR, consisting of the H1 and H2 subunits, that is capable of specific ligand binding and uptake. Copyright 2002 S. Karger AG, Basel

  10. Renal tubular dysfunction and abnormalities of calcium metabolism in cadmium workers

    PubMed Central

    Kazantzis, George

    1979-01-01

    Tubular proteinuria is generally accepted as the critical effect following long-term, low-level exposure to cadmium as seen in an industrial environment. This effect may not be of immediate importance to the health of the individual, but the significance, in terms of long-term morbidity and mortality, of the renal tubular defect of which it is an indicator is not fully understood, and certain sequelae may have remained unrecognized due to inadequate follow-up. Follow-up studies have been performed in nine of 12 workers who were initially investigated in 1962. In six of the men exposures ranged from 28 to 45 years to cadmium sulfide dust and for shorter periods in the earlier years to cadmium oxide fume and dust. These six men had tubular proteinuria when first seen, and this has persisted in the five survivors. All six men had hypercalciuria, and two of them became recurrent stone formers. One man whose urinary calcium excretion later fell to a low level more recently developed vitamin D resistant osteomalacia. In addition, each of the six men had exhibited some, but not all, of a variety of biochemical abnormalities related to other proximal renal tubular defects, and the worker who developed osteomalacia had additional evidence of a distal tubular defect. The five survivors also have evidence of slowly progressive deterioration in glomerular function. Follow-up of this small group has shown that renal tubular dysfunction in cadmium workers may continue symptom-free for long intervals, but in a proportion of cases serious clinical effects may develop after a number of years. ImagesFIGURE 1. PMID:488032

  11. Shear Stress-Induced Alteration of Epithelial Organization in Human Renal Tubular Cells

    PubMed Central

    Belloy, Marcy; Saulnier-Blache, Jean-Sébastien; Casemayou, Audrey; Ducasse, Laure; Grès, Sandra; Bellière, Julie; Caubet, Cécile; Bascands, Jean-Loup; Schanstra, Joost P.; Buffin-Meyer, Bénédicte

    2015-01-01

    Tubular epithelial cells in the kidney are continuously exposed to urinary fluid shear stress (FSS) generated by urine movement and recent in vitro studies suggest that changes of FSS could contribute to kidney injury. However it is unclear whether FSS alters the epithelial characteristics of the renal tubule. Here, we evaluated in vitro and in vivo the influence of FSS on epithelial characteristics of renal proximal tubular cells taking the organization of junctional complexes and the presence of the primary cilium as markers of epithelial phenotype. Human tubular cells (HK-2) were subjected to FSS (0.5 Pa) for 48h. Control cells were maintained under static conditions. Markers of tight junctions (Claudin-2, ZO-1), Par polarity complex (Pard6), adherens junctions (E-Cadherin, β-Catenin) and the primary cilium (α-acetylated Tubulin) were analysed by quantitative PCR, Western blot or immunocytochemistry. In response to FSS, Claudin-2 disappeared and ZO-1 displayed punctuated and discontinuous staining in the plasma membrane. Expression of Pard6 was also decreased. Moreover, E-Cadherin abundance was decreased, while its major repressors Snail1 and Snail2 were overexpressed, and β-Catenin staining was disrupted along the cell periphery. Finally, FSS subjected-cells exhibited disappeared primary cilium. Results were confirmed in vivo in a uninephrectomy (8 months) mouse model where increased FSS induced by adaptive hyperfiltration in remnant kidney was accompanied by both decreased epithelial gene expression including ZO-1, E-cadherin and β-Catenin and disappearance of tubular cilia. In conclusion, these results show that proximal tubular cells lose an important number of their epithelial characteristics after long term exposure to FSS both in vitro and in vivo. Thus, the changes in urinary FSS associated with nephropathies should be considered as potential insults for tubular cells leading to disorganization of the tubular epithelium. PMID:26146837

  12. Shear Stress-Induced Alteration of Epithelial Organization in Human Renal Tubular Cells.

    PubMed

    Maggiorani, Damien; Dissard, Romain; Belloy, Marcy; Saulnier-Blache, Jean-Sébastien; Casemayou, Audrey; Ducasse, Laure; Grès, Sandra; Bellière, Julie; Caubet, Cécile; Bascands, Jean-Loup; Schanstra, Joost P; Buffin-Meyer, Bénédicte

    2015-01-01

    Tubular epithelial cells in the kidney are continuously exposed to urinary fluid shear stress (FSS) generated by urine movement and recent in vitro studies suggest that changes of FSS could contribute to kidney injury. However it is unclear whether FSS alters the epithelial characteristics of the renal tubule. Here, we evaluated in vitro and in vivo the influence of FSS on epithelial characteristics of renal proximal tubular cells taking the organization of junctional complexes and the presence of the primary cilium as markers of epithelial phenotype. Human tubular cells (HK-2) were subjected to FSS (0.5 Pa) for 48 h. Control cells were maintained under static conditions. Markers of tight junctions (Claudin-2, ZO-1), Par polarity complex (Pard6), adherens junctions (E-Cadherin, β-Catenin) and the primary cilium (α-acetylated Tubulin) were analysed by quantitative PCR, Western blot or immunocytochemistry. In response to FSS, Claudin-2 disappeared and ZO-1 displayed punctuated and discontinuous staining in the plasma membrane. Expression of Pard6 was also decreased. Moreover, E-Cadherin abundance was decreased, while its major repressors Snail1 and Snail2 were overexpressed, and β-Catenin staining was disrupted along the cell periphery. Finally, FSS subjected-cells exhibited disappeared primary cilium. Results were confirmed in vivo in a uninephrectomy (8 months) mouse model where increased FSS induced by adaptive hyperfiltration in remnant kidney was accompanied by both decreased epithelial gene expression including ZO-1, E-cadherin and β-Catenin and disappearance of tubular cilia. In conclusion, these results show that proximal tubular cells lose an important number of their epithelial characteristics after long term exposure to FSS both in vitro and in vivo. Thus, the changes in urinary FSS associated with nephropathies should be considered as potential insults for tubular cells leading to disorganization of the tubular epithelium.

  13. Albumin impairs renal tubular tight junctions via targeting the NLRP3 inflammasome.

    PubMed

    Zhuang, Yibo; Hu, Caiyu; Ding, Guixia; Zhang, Yue; Huang, Songming; Jia, Zhanjun; Zhang, Aihua

    2015-05-01

    Proteinuria is, not only a hallmark of glomerular disease, but also a contributor to kidney injury. However, its pathogenic mechanism is still elusive. In the present study, the effects of albumin on renal tubular tight junctions and the potential molecular mechanisms of those effects were investigated. In mouse proximal tubular cells (mPTCs), albumin treatment resulted in a significant loss of the cellular tight junction proteins zonula occludens-1 (ZO-1) and claudin-1 in a time- and dose-dependent manner, indicating a severe impairment of the tight junctions. On the basis of our previous study showing that albumin stimulated NLRP3 [neuronal apoptosis inhibitor protein, major histocompatibility complex class 2 transcription activator, incompatibility locus protein from Podospora anserina, and telomerase-associated protein (NACHT); leucine-rich repeat (LRR); and pyrin domain (PYD) domains-containing protein 3] inflammasome activation in mPTCs, we pretreated mPTCs with NLRP3 siRNA (siNLRP3) and found that NLRP3 knockdown significantly blocked the downregulation of ZO-1 and claudin-1 induced by albumin. Similarly, in albumin-overloaded wild-type mice, both ZO-1 and claudin-1 were downregulated at the protein and mRNA levels in parallel with the impaired formation of the tight junctions on transmission electron microscopy and the abnormal renal tubular morphology on periodic acid-Schiff staining, which contrasted with the stimulation of NLRP3 in the renal tubules. In contrast, NLRP3 knockout (NLRP3(-/-)) mice preserved normal ZO-1 and claudin-1 expression as well as largely normal tight junctions and tubular morphology. More importantly, deletion of the NLRP3 pathway downstream component caspase-1 similarly blocked the albumin overload-induced downregulation of ZO-1 and claudin-1. Taken together, these findings demonstrated an important role of the albumin-NLRP3 inflammasome axis in mediating the impairment of renal tubular tight junctions and integrity. Copyright

  14. Increased renal tubular sodium reabsorption during exercise-induced hypervolemia in humans

    NASA Technical Reports Server (NTRS)

    Nagashima, K.; Wu, J.; Kavouras, S. A.; Mack, G. W.

    2001-01-01

    We tested the hypothesis that renal tubular Na(+) reabsorption increased during the first 24 h of exercise-induced plasma volume expansion. Renal function was assessed 1 day after no-exercise control (C) or intermittent cycle ergometer exercise (Ex, 85% of peak O(2) uptake) for 2 h before and 3 h after saline loading (12.5 ml/kg over 30 min) in seven subjects. Ex reduced renal blood flow (p-aminohippurate clearance) compared with C (0.83 +/- 0.12 vs. 1.49 +/- 0.24 l/min, P < 0.05) but did not influence glomerular filtration rates (97 +/- 10 ml/min, inulin clearance). Fractional tubular reabsorption of Na(+) in the proximal tubules was higher in Ex than in C (P < 0.05). Saline loading decreased fractional tubular reabsorption of Na(+) from 99.1 +/- 0.1 to 98.7 +/- 0.1% (P < 0.05) in C but not in Ex (99.3 +/- 0.1 to 99.4 +/- 0.1%). Saline loading reduced plasma renin activity and plasma arginine vasopressin levels in C and Ex, although the magnitude of decrease was greater in C (P < 0.05). These results indicate that, during the acute phase of exercise-induced plasma volume expansion, increased tubular Na(+) reabsorption is directed primarily to the proximal tubules and is associated with a decrease in renal blood flow. In addition, saline infusion caused a smaller reduction in fluid-regulating hormones in Ex. The attenuated volume-regulatory response acts to preserve distal tubular Na(+) reabsorption during saline infusion 24 h after exercise.

  15. Increased renal tubular sodium reabsorption during exercise-induced hypervolemia in humans

    NASA Technical Reports Server (NTRS)

    Nagashima, K.; Wu, J.; Kavouras, S. A.; Mack, G. W.

    2001-01-01

    We tested the hypothesis that renal tubular Na(+) reabsorption increased during the first 24 h of exercise-induced plasma volume expansion. Renal function was assessed 1 day after no-exercise control (C) or intermittent cycle ergometer exercise (Ex, 85% of peak O(2) uptake) for 2 h before and 3 h after saline loading (12.5 ml/kg over 30 min) in seven subjects. Ex reduced renal blood flow (p-aminohippurate clearance) compared with C (0.83 +/- 0.12 vs. 1.49 +/- 0.24 l/min, P < 0.05) but did not influence glomerular filtration rates (97 +/- 10 ml/min, inulin clearance). Fractional tubular reabsorption of Na(+) in the proximal tubules was higher in Ex than in C (P < 0.05). Saline loading decreased fractional tubular reabsorption of Na(+) from 99.1 +/- 0.1 to 98.7 +/- 0.1% (P < 0.05) in C but not in Ex (99.3 +/- 0.1 to 99.4 +/- 0.1%). Saline loading reduced plasma renin activity and plasma arginine vasopressin levels in C and Ex, although the magnitude of decrease was greater in C (P < 0.05). These results indicate that, during the acute phase of exercise-induced plasma volume expansion, increased tubular Na(+) reabsorption is directed primarily to the proximal tubules and is associated with a decrease in renal blood flow. In addition, saline infusion caused a smaller reduction in fluid-regulating hormones in Ex. The attenuated volume-regulatory response acts to preserve distal tubular Na(+) reabsorption during saline infusion 24 h after exercise.

  16. Renal tubular acidosis type IV as a complication of lupus nephritis.

    PubMed

    Sánchez-Marcos, C; Hoffman, V; Prieto-González, S; Hernández-Rodríguez, J; Espinosa, G

    2016-03-01

    Renal tubular acidosis (RTA) is a rare complication of renal involvement of systemic lupus erythematosus (SLE). We describe a 24-year-old male with type IV lupus nephropathy as a presenting manifestation of SLE. He presented with improvement of renal function following induction therapy with three pulses of methylprednisolone and 500 mg biweekly pulses of cyclophosphamide. However, a week after the first pulse of cyclophosphamide, the patient presented with a significant increase in legs edema and severe hyperkalemia. Type IV RTA associated with hyporeninemic hypoaldosteronism was suspected in the presence of metabolic acidosis with a normal anion gap, severe hyperkalemia without worsening renal function, and urinary pH of 5. RTA was confirmed with a transtubular potassium concentration gradient of 2 and low levels of plasma aldosterone, renin, angiotensin II, and cortisol. Intravenous bicarbonate, high-dose furosemide, and fludrocortisone were administered with normalization of potassium levels and renal function.

  17. Kidney specific protein-positive cells derived from embryonic stem cells reproduce tubular structures in vitro and differentiate into renal tubular cells.

    PubMed

    Morizane, Ryuji; Monkawa, Toshiaki; Fujii, Shizuka; Yamaguchi, Shintaro; Homma, Koichiro; Matsuzaki, Yumi; Okano, Hideyuki; Itoh, Hiroshi

    2014-01-01

    Embryonic stem cells and induced pluripotent stem cells have the ability to differentiate into various organs and tissues, and are regarded as new tools for the elucidation of disease mechanisms as well as sources for regenerative therapies. However, a method of inducing organ-specific cells from pluripotent stem cells is urgently needed. Although many scientists have been developing methods to induce various organ-specific cells from pluripotent stem cells, renal lineage cells have yet to be induced in vitro because of the complexity of kidney structures and the diversity of kidney-component cells. Here, we describe a method of inducing renal tubular cells from mouse embryonic stem cells via the cell purification of kidney specific protein (KSP)-positive cells using an anti-KSP antibody. The global gene expression profiles of KSP-positive cells derived from ES cells exhibited characteristics similar to those of cells in the developing kidney, and KSP-positive cells had the capacity to form tubular structures resembling renal tubular cells when grown in a 3D culture in Matrigel. Moreover, our results indicated that KSP-positive cells acquired the characteristics of each segment of renal tubular cells through tubular formation when stimulated with Wnt4. This method is an important step toward kidney disease research using pluripotent stem cells, and the development of kidney regeneration therapies.

  18. Renal Differentiation of Mesenchymal Stem Cells Seeded on Nanofibrous Scaffolds Improved by Human Renal Tubular Cell Lines-Conditioned Medium.

    PubMed

    Ardeshirylajimi, Abdolreza; Vakilian, Saeid; Salehi, Mohammad; Mossahebi-Mohammadi, Majid

    Kidney injuries and renal dysfunctions are one of the most important clinical problems, and tissue engineering could be a valuable method for solving it. The objective of this study was to investigate the synergistic effect of renal cell line-conditioned medium and Polycaprolactone (PCL) nanofibers on renal differentiation of human mesenchymal stem cells (MSCs). In the current study, after stem cells isolation and characterization, PCL nanofibrous scaffold was fabricated using electrospinning methods and characterized morphologically, mechanically, and for biocompatibility. The renal differentiation of seeded MSCs on the surface of PCL nanofibers with and without human renal tubular cell lines-conditioned medium was investigated by evaluation of eight important renal-related genes expression by real-time reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemistry. Fabricated nanofibrous scaffolds were good in all characterized items. Almost highest expression of all genes was detected in stem cells seeded on PCL under conditioned media in comparison with the stem cells seeded on PCL, tissue culture polystyrene (TCPS) under renal induction medium, and TCPS under conditioned medium. According to the results, PCL nanofibers in contribution with conditioned medium can provide the optimal conditions for renal differentiation of MSCs and could be a promising candidate for renal tissue engineering application.

  19. An experimental renal acidification defect in patients with hereditary fructose intolerance. I. Its resemblance to renal tubular acidosis.

    PubMed

    Morris, R C

    1968-06-01

    In three unrelated patients with hereditary fructose intolerance (HFI), but in none of five normal subjects, the experimental administration of fructose invariably induced a reversible dysfunction of the renal tubule with biochemical and physiological characteristics of renal tubular acidosis. During a state of ammonium chloride-induced acidosis, (a) urinary pH was greater than six and the rate of excretion of net acid (titratable acid plus ammonium minus bicarbonate) was inappropriately low, (b) the glomerular filtration rate remained unchanged or decreased modestly, and (c) urinary excretion of titratable acid increased briskly with diuresis of infused phosphate, although urinary pH changed little. The tubular dysfunction, which also includes impaired tubular reabsorption of alpha amino nitrogen and phosphate, persisted throughout administration of fructose and disappeared afterward. The tubular dysfunction was not causally dependent on hypoglucosemia, ammonium chloride-induced acidosis or osmotic diuresis. Rather, it appeared causally related to the fructose-induced metabolic abnormality of patients with HFI. The causal enzymatic defect, the virtual absence of fructose-1-phosphate aldolase, occurs in the kidney as well as in the liver of patients with HFI.

  20. Metformin inhibits advanced glycation end products (AGEs)-induced renal tubular cell injury by suppressing reactive oxygen species generation via reducing receptor for AGEs (RAGE) expression.

    PubMed

    Ishibashi, Y; Matsui, T; Takeuchi, M; Yamagishi, S

    2012-11-01

    Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in tubulointerstitial damage in diabetic nephropathy. Recently, metformin has been shown to ameliorate tubular injury both in cell culture and diabetic animal model. However, effects of metformin on AGEs-induced tubular cell apoptosis and damage remain unknown. We examined here whether and how metformin could block the AGEs-RAGE-elicited tubular cell injury in vitro. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. Reactive oxygen species (ROS) generation was measured with dihydroethidium staining. Apoptosis was evaluated by DNA fragmentation and annexin V expression level. AGEs upregulated RAGE mRNA levels and subsequently increased ROS generation and intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and transforming growth factor-β gene expression in human renal proximal tubular cells, all of which were significantly blocked by the treatment of 0.01 and 0.1 mM metformin. Compound C, an inhibitor of AMP-activated protein kinase significantly blocked the effects of metformin on RAGE gene expression and ROS generation in AGEs-exposed tubular cells. Furthermore, metformin dose-dependently inhibited the AGEs-induced apoptotic cell death of tubular cells; 1 mM metformin completely suppressed the pro-apoptotic effects of AGEs in 2 different assay systems. Our present study suggests that metformin could inhibit the AGEs-induced apoptosis and inflammatory and fibrotic reactions in tubular cells probably by reducing ROS generation via suppression of RAGE expression through AMP-activated protein kinase activation. Metformin may protect against tubular cell injury in diabetic nephropathy by blocking the AGEs-RAGE-ROS axis.

  1. Interferon-γ Reduces the Proliferation of Primed Human Renal Tubular Cells

    PubMed Central

    García-Sánchez, Omar; López-Novoa, José Miguel; López-Hernández, Francisco J.

    2014-01-01

    Background/Aims Chronic kidney disease (CKD) is a progressive deterioration of the kidney function, which may eventually lead to renal failure and the need for dialysis or kidney transplant. Whether initiated in the glomeruli or the tubuli, CKD is characterized by progressive nephron loss, for which the process of tubular deletion is of key importance. Tubular deletion results from tubular epithelial cell death and defective repair, leading to scarring of the renal parenchyma. Several cytokines and signaling pathways, including transforming growth factor-β (TGF-β) and the Fas pathway, have been shown to participate in vivo in tubular cell death. However, there is some controversy about their mode of action, since a direct effect on normal tubular cells has not been demonstrated. We hypothesized that epithelial cells would require specific priming to become sensitive to TGF-β or Fas stimulation and that this priming would be brought about by specific mediators found in the pathological scenario. Methods Herein we studied whether the combined effect of several stimuli known to take part in CKD progression, namely TGF-β, tumor necrosis factor-α, interferon-γ (IFN-γ), and Fas stimulation, on primed resistant human tubular cells caused cell death or reduced proliferation. Results We demonstrate that these cytokines have no synergistic effect on the proliferation or viability of human kidney (HK2) cells. We also demonstrate that IFN-γ, but not the other stimuli, reduces the proliferation of cycloheximide-primed HK2 cells without affecting their viability. Conclusion Our results point at a potentially important role of IFN-γ in defective repair, leading to nephron loss during CKD. PMID:24575118

  2. Glomerular and Tubular Renal Function after Repeated Once-Daily Tobramycin Courses in Cystic Fibrosis Patients.

    PubMed

    Stehling, Florian; Büscher, Rainer; Grosse-Onnebrink, Jörg; Hoyer, Peter F; Mellies, Uwe

    2017-01-01

    Introduction. Antibiotic treatment regimens against Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients often include aminoglycoside antibiotics that may cause chronic renal failure after repeated courses. Aminoaciduria is an early marker of acute aminoglycoside-induced renal tubular dysfunction. We hypothesized that urinary amino acid reabsorption is decreased after repeated once-daily tobramycin therapies. Methods. In this prospective cross-sectional study creatinine clearance was estimated by the Schwartz and the Cockcroft-Gault formula. Tubular amino acid reabsorption was determined by ion exchange chromatography in 46 patients with CF who received multiple tobramycin courses (6.3 ± 10.1 (1-57)) in a once-daily dosing regimen and 10 who did not. Results. Estimated creatinine clearance employing the Cockcroft-Gault was mildly reduced in 17/46 (37%) of the patients who received tobramycin and 5/10 (50%) of the patients who did not but in none using the Schwartz formula. No association with lifetime tobramycin courses was found. Tubular amino acid reabsorption was not influenced by the amount of once-daily tobramycin courses. Conclusion. Clinically not significant reduction of eCCL occurred in a minority of CF patients. However, chronic tubular dysfunction was not present in patients with CF repeatedly treated with tobramycin in the once-daily dosing scheme.

  3. Glomerular and Tubular Renal Function after Repeated Once-Daily Tobramycin Courses in Cystic Fibrosis Patients

    PubMed Central

    Büscher, Rainer; Grosse-Onnebrink, Jörg; Hoyer, Peter F.; Mellies, Uwe

    2017-01-01

    Introduction. Antibiotic treatment regimens against Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients often include aminoglycoside antibiotics that may cause chronic renal failure after repeated courses. Aminoaciduria is an early marker of acute aminoglycoside-induced renal tubular dysfunction. We hypothesized that urinary amino acid reabsorption is decreased after repeated once-daily tobramycin therapies. Methods. In this prospective cross-sectional study creatinine clearance was estimated by the Schwartz and the Cockcroft-Gault formula. Tubular amino acid reabsorption was determined by ion exchange chromatography in 46 patients with CF who received multiple tobramycin courses (6.3 ± 10.1 (1–57)) in a once-daily dosing regimen and 10 who did not. Results. Estimated creatinine clearance employing the Cockcroft-Gault was mildly reduced in 17/46 (37%) of the patients who received tobramycin and 5/10 (50%) of the patients who did not but in none using the Schwartz formula. No association with lifetime tobramycin courses was found. Tubular amino acid reabsorption was not influenced by the amount of once-daily tobramycin courses. Conclusion. Clinically not significant reduction of eCCL occurred in a minority of CF patients. However, chronic tubular dysfunction was not present in patients with CF repeatedly treated with tobramycin in the once-daily dosing scheme. PMID:28133546

  4. Novel VIPAS39 mutation in a syndromic patient with arthrogryposis, renal tubular dysfunction and intrahepatic cholestasis.

    PubMed

    Aflatounian, Majid; Smith, Holly; Farahani, Fatemeh; Tofighi Naeem, Azam; Straatman-Iwanowska, Anna; Zoghi, Samaneh; Khatri, Urvi; Tajdini, Parisa; Fallahi, Gholam Hossein; Gissen, Paul; Rezaei, Nima

    2016-04-01

    ARC syndrome is a rare autosomal recessive disease, characterized by arthrogryposis, renal tubular dysfunction and cholestasis. Herein a 2.5 month old infant with dysmorphic features, including small anterior fontanel, low set ears, beaked nose and high arched palate is presented who was referred because of icterus. He also suffered from some additional anomalies, including unilateral choanal atresia, club foot, and bilateral developmental dislocation of hip, while further studies showed renal tubular acidosis and hearing impairment in addition to cholestasis. Genetic studies showed a homozygous mutation in the VIPAS39 gene. Making the definite diagnosis of the syndrome is important, while increased risk of mutation in other siblings highlights the importance of prenatal diagnosis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. An integrative overview on the mechanisms underlying the renal tubular cytotoxicity of gentamicin.

    PubMed

    Quiros, Yaremi; Vicente-Vicente, Laura; Morales, Ana I; López-Novoa, José M; López-Hernández, Francisco J

    2011-02-01

    Gentamicin is an aminoglycoside antibiotic widely used against infections by Gram-negative microorganisms. Nephrotoxicity is the main limitation to its therapeutic efficacy. Gentamicin nephrotoxicity occurs in 10-20% of therapeutic regimes. A central aspect of gentamicin nephrotoxicity is its tubular effect, which may range from a mere loss of the brush border in epithelial cells to an overt tubular necrosis. Tubular cytotoxicity is the consequence of many interconnected actions, triggered by drug accumulation in epithelial tubular cells. Accumulation results from the presence of the endocytic receptor complex formed by megalin and cubulin, which transports proteins and organic cations inside the cells. Gentamicin then accesses and accumulates in the endosomal compartment, the Golgi and endoplasmic reticulum (ER), causes ER stress, and unleashes the unfolded protein response. An excessive concentration of the drug over an undetermined threshold destabilizes intracellular membranes and the drug redistributes through the cytosol. It then acts on mitochondria to unleash the intrinsic pathway of apoptosis. In addition, lysosomal cathepsins lose confinement and, depending on their new cytosolic concentration, they contribute to the activation of apoptosis or produce a massive proteolysis. However, other effects of gentamicin have also been linked to cell death, such as phospholipidosis, oxidative stress, extracellular calcium-sensing receptor stimulation, and energetic catastrophe. Besides, indirect effects of gentamicin, such as reduced renal blood flow and inflammation, may also contribute or amplify its cytotoxicity. The purpose of this review was to critically integrate all these effects and discuss their relative contribution to tubular cell death.

  6. Transient hyperkalemic distal renal tubular acidosis with bicarbonate wasting in a young child.

    PubMed

    Khositseth, Sookkasem

    2011-12-01

    Distal renal tubular acidosis is a clinical syndrome characterized by inability to acidify urine in the presence of metabolic acidosis. Classic dRTA patients exhibit failure to thrive, polyuria, metabolic acidosis and hypokalemia. Hyperkalemic dRTA without underlying disease is very rare. Transient bicarbonate wasting accompanied with hypokalemic dRTA was reported in infants. Herein, a transient hyperkalemic dRTA with bicarbonate wasting was reported in a young child.

  7. Renal tubular dysgenesis, absent nipples, and multiple malformations in three brothers: a new, lethal syndrome.

    PubMed

    Hisama, F M; Reyes-Mugica, M; Wargowski, D S; Thompson, K J; Mahoney, M J

    1998-12-04

    We report on three brothers with renal tubular dysgenesis and absent nipples, each also had other malformations including pre-auricular pits and a preauricular tag, branchial clefts, choanal atresia, pulmonary lobation anomaly, ventricular septal defect, type IIB interrupted aortic arch, absent gallbladder, absent thymus, parathyroid gland, accessory spleen, imperforate anus, clinodactyly, and broad digits and small nails. All three infants died neonatally. This pattern of clinical malformations appears to be a previously unreported syndrome.

  8. A case of distal renal tubular acidosis, Southeast Asian ovalocytosis and possible fluorosis.

    PubMed

    Vithanage, J P; Ekanayake, M

    2009-03-01

    A 39-year old man had periodic paralysis due to hypokalaemia. Investigations led to the diagnosis of distal renal tubular acidosis (dRTA) and Southeast Asian ovalocytosis (SAO). Both can originate in mutations of the anion-exchanger 1 gene (AE1), which codes for band 3, the bicarbonate/chloride exchanger in both the red cell membrane and the basolateral membrane of the collecting tubule alpha-intercalated cell. The finding of diffuse osteosclerosis led to the suspicion of coexisting fluorosis.

  9. Furosemide/Fludrocortisone Test and Clinical Parameters to Diagnose Incomplete Distal Renal Tubular Acidosis in Kidney Stone Formers.

    PubMed

    Dhayat, Nasser A; Gradwell, Michael W; Pathare, Ganesh; Anderegg, Manuel; Schneider, Lisa; Luethi, David; Mattmann, Cedric; Moe, Orson W; Vogt, Bruno; Fuster, Daniel G

    2017-09-07

    Incomplete distal renal tubular acidosis is a well known cause of calcareous nephrolithiasis but the prevalence is unknown, mostly due to lack of accepted diagnostic tests and criteria. The ammonium chloride test is considered as gold standard for the diagnosis of incomplete distal renal tubular acidosis, but the furosemide/fludrocortisone test was recently proposed as an alternative. Because of the lack of rigorous comparative studies, the validity of the furosemide/fludrocortisone test in stone formers remains unknown. In addition, the performance of conventional, nonprovocative parameters in predicting incomplete distal renal tubular acidosis has not been studied. We conducted a prospective study in an unselected cohort of 170 stone formers that underwent sequential ammonium chloride and furosemide/fludrocortisone testing. Using the ammonium chloride test as gold standard, the prevalence of incomplete distal renal tubular acidosis was 8%. Sensitivity and specificity of the furosemide/fludrocortisone test were 77% and 85%, respectively, yielding a positive predictive value of 30% and a negative predictive value of 98%. Testing of several nonprovocative clinical parameters in the prediction of incomplete distal renal tubular acidosis revealed fasting morning urinary pH and plasma potassium as the most discriminative parameters. The combination of a fasting morning urinary threshold pH <5.3 with a plasma potassium threshold >3.8 mEq/L yielded a negative predictive value of 98% with a sensitivity of 85% and a specificity of 77% for the diagnosis of incomplete distal renal tubular acidosis. The furosemide/fludrocortisone test can be used for incomplete distal renal tubular acidosis screening in stone formers, but an abnormal furosemide/fludrocortisone test result needs confirmation by ammonium chloride testing. Our data furthermore indicate that incomplete distal renal tubular acidosis can reliably be excluded in stone formers by use of nonprovocative clinical

  10. [Sjögren syndrome associated with renal tubular acidosis type I].

    PubMed

    Górriz, L; Molino, R; Arjona, D; Estripeaut, D

    2000-01-01

    Primary Sjögren's Syndrome complicated with a renal tubular acidosis type 1 and hypocalcemic paralysis, as the principal clinical manifestation, is uncommon. Although the initial manifestations of the nephropathy are not well understood, it is believed that the invasion of mononuclear cells and the high level of circulating antibodies, play an important role in the pathogenesis of the disease. We present a patient with hypocalcemic paralysis as an initial manifestation of a latent Sjögren's disease. The glandular biopsy was normal, suggesting a mayor participation of an immunological humoral factor in the renal lesion.

  11. Dental Aspect of Distal Tubular Renal Acidosis with Genu Valgum Secondary to Rickets: A Case Report

    PubMed Central

    Bahadure, Rakesh N.; Thosar, Nilima; Kriplani, Ritika; Baliga, Sudhindra; Fulzele, Punit

    2012-01-01

    Distal renal tubular acidosis is a disease that occurs when the kidneys do not remove acid properly into the urine, leaving the blood too acidic (called acidosis). Distal renal tubular acidosis (type I RTA) is caused by a defect in the kidney tubes that causes acid to build up in the bloodstream. It ultimately results rickets which include chronic skeletal pain, in skeletal deformities, skeletal fractures. Rickets is among the most frequent childhood diseases in many developing countries. Dental problems in rickets include delayed eruption of permanent teeth, premature fall of deciduous teeth, defects in structure of teeth, enamel defects in permanent teeth (hypoplastic), pulp defects, intraglobular dentine, and caries tooth. Herewith, reported a case of distal tubular renal acidosis with genu valgum secondary to rickets, with pain and extraoral swelling associated with right and left mandibular 1st permanent molars. Teeth were infected with pulp without being involved with caries. Radiographically cracks in enamel and dentin were observed. Pulp revascularization with 46 and root canal treatment was done for 36 with followup of 1 year. PMID:22567455

  12. Hyperosmolarity Induces Armanni-Ebstein-like Renal Tubular Epithelial Swelling and Cytoplasmic Vacuolization.

    PubMed

    Zhou, Chong; Vink, Robert; Byard, Roger W

    2017-01-01

    Armanni-Ebstein lesions have been considered pathognomonic for diabetes mellitus and appear as markedly swollen renal tubular epithelial cells with cytoplasmic clearing and glycogen accumulation. However, the extent to which hyperosmolarity contributes to the Armanni-Ebstein phenotype is unclear. Ten sheep were injected intravenously with 20% mannitol at 11 mOsm/kg, and subsequent histological evaluation of the kidneys showed variable degrees of osmotic nephrosis and cytoplasmic clearing of renal tubular epithelial cells similar to that seen with Armanni-Ebstein lesions. However, although morphological changes similar to Armanni-Ebstein lesions could be produced, no intracytoplasmic glycogen was demonstrated with periodic Acid-Schiff (PAS) stain. This suggests that while hyperosmolarity may contribute to the development of an Armanni-Ebstein phenotype, glycogen accumulation may result from the more complex metabolic effects of glucose on renal tubular epithelial cells. Thus, when Armanni/Ebstein-like vacuolizations are seen at autopsy, a confirmatory PAS stain is recommended because of the potential effect of hyperosmolar states.

  13. Macropinocytosis is the major mechanism for endocytosis of calcium oxalate crystals into renal tubular cells.

    PubMed

    Kanlaya, Rattiyaporn; Sintiprungrat, Kitisak; Chaiyarit, Sakdithep; Thongboonkerd, Visith

    2013-01-01

    During an initial phase of kidney stone formation, the internalization of calcium oxalate (CaOx) crystals by renal tubular cells has been thought to occur via endocytosis. However, the precise mechanism of CaOx crystal endocytosis remained unclear. In the present study, MDCK renal tubular cells were pretreated with inhibitors specific to individual endocytic pathways, including nystatin (lipid raft/caveolae-mediated), cytochalasin D (actin-dependent or macropinocytosis), and chlorpromazine (CPZ; clathrin-mediated) before exposure to plain (non-labeled), or fluorescence-labeled CaOx monohydrate (COM) crystals. Quantitative analysis by flow cytometry revealed that pretreatment with nystatin and CPZ slightly decreased the crystal internalization, whereas the cytochalasin D pretreatment caused a marked decrease in crystal uptake. Immunofluorescence study and laser-scanning confocal microscopic examination confirmed that the cytochalasin D-pretreated cells had dramatic decrease of the internalized crystals, whereas the total number of crystals interacted with the cells was unchanged (crystals could adhere but were not internalized). These data have demonstrated for the first time that renal tubular cells endocytose COM crystals mainly via macropinocytosis. These novel findings will be useful for further tracking the endocytosed crystals inside the cells during the course of kidney stone formation.

  14. Exosome production and its regulation of EGFR during wound healing in renal tubular cells.

    PubMed

    Zhou, Xiangjun; Zhang, Wei; Yao, Qisheng; Zhang, Hao; Dong, Guie; Zhang, Ming; Liu, Yutao; Chen, Jian-Kang; Dong, Zheng

    2017-06-01

    Kidney repair following injury involves the reconstitution of a structurally and functionally intact tubular epithelium. Growth factors and their receptors, such as EGFR, are important in the repair of renal tubules. Exosomes are cell-produced small (~100 nm in diameter) vesicles that contain and transfer proteins, lipids, RNAs, and DNAs between cells. In this study, we examined the relationship between exosome production and EGFR activation and the potential role of exosome in wound healing. EGFR activation occurred shortly after scratch wounding in renal tubular cells. Wound repair after scratching was significantly promoted by EGF and suppressed by EGFR inhibitor gefitinib. Interestingly, scratch wounding induced a significant increase of exosome production. The exosome production was decreased by EGF and increased by gefitinib, suggesting a suppressive role of EGFR signaling in exosome production. Conversely, inhibition of exosome release by GW4869 and manumycin A markedly increased EGFR activation and promoted wound healing. Moreover, exosomes derived from scratch-wounding cells could inhibit wound healing. Collectively, the results indicate that wound healing in renal tubular cells is associated with EGFR activation and exosome production. Although EGFR activation promotes wound healing, released exosomes may antagonize EGFR activation and wound healing. Copyright © 2017 the American Physiological Society.

  15. Tauroursodeoxycholic Acid Attenuates Renal Tubular Injury in a Mouse Model of Type 2 Diabetes

    PubMed Central

    Zhang, Jing; Fan, Ying; Zeng, Chuchu; He, Li; Wang, Niansong

    2016-01-01

    Renal tubular injury is a critical factor in the pathogenesis of diabetic nephropathy (DN). Endoplasmic reticulum (ER) stress is involved in diabetic nephropathy. Tauroursodeoxycholic acid (TUDCA) is an effective inhibitor of ER stress. Here, we investigated the role of TUDCA in the progression of tubular injury in DN. For eight weeks, being treated with TUDCA at 250 mg/kg intraperitoneal injection (i.p.) twice a day, diabetic db/db mice had significantly reduced blood glucose, albuminuria and attenuated renal histopathology. These changes were associated with a significant decreased expression of ER stress markers. At the same time, diabetic db/db mice had more TUNEL-positive nuclei in the renal tubule, which were attenuated by TUDCA treatment, along with decreases in ER stress–associated apoptotic markers in the kidneys. In summary, the effect of TUDCA on tubular injury, in part, is associated with inhibition of ER stress in the kidneys of diabetic db/db mice. TUDCA shows potential as a therapeutic target for the prevention and treatment of DN. PMID:27669287

  16. Effects of prednisone on biomarkers of tubular damage induced by radiocontrast in interventional cardiology.

    PubMed

    Ribichini, Flavio; Gambaro, Alessia; Pighi, Michele; Pesarini, Gabriele; Ferraro, Pietro Manuel; Zuppi, Cecilia; Baroni, Silvia; Penitente, Romina; Ferrero, Valeria; Vassanelli, Corrado

    2013-01-01

    Contrast-induced nephropathy (CI-AKI) is a complication of diagnostic/therapeutic hemodynamic procedures in cardiology, which may also cause renal cholesterolinic atheroembolism. Despite the 
severe clinical impact of these complications, there is no optimal therapy for preventing and treating them. We suggest a short course of high-dose steroids as an effective preventive measure. Patients at risk of CI-AKI (n = 38) undergoing cardiovascular procedures were assigned 1:1 to 1 of 2 experimental arms (prednisone+hydration vs. hydration alone). Oral prednisone 1 mg/kg was administered 12 hours before, at 6 am on the same day, and 24 hours following the procedure. Serum creatinine was tested immediately before and again 24-48 hours after the procedure; neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), protein and albumin were assayed in spot urine before and 6 hours after the procedure.
 NGAL and KIM-1 tended to rise after the procedure, but to a lesser degree in the prednisone group (delta NGAL: hydration = +128%, prednisone = +46%; 
p = 0.26; delta KIM-1: hydration = +99%, prednisone = +11%; p = 0.02). Proteinuria and albuminuria decreased significantly in the prednisone group. In 5 patients developing CI-AKI, their delta NGAL and delta KIM-1 did not differ from the values seen in patients without 
CI-AKI. Hypertension, peripheral arteriopathy and use of low-dose aspirin or diuretics were positive predictors of baseline NGAL, while treatment with calcium channel blockers and statins were negative predictors. Statins were negative predictors of baseline KIM-1. A short course of prednisone reduces the procedure-induced changes in biomarkers of renal tubular damage. This study suggests that steroids had a tubule-protecting effect.

  17. [Itai-itai disease: cadmium-induced renal tubular osteomalacia].

    PubMed

    Aoshima, Keiko

    2012-01-01

    Cadmium (Cd) is one of the most toxic elements to which humans could be exposed at work or in the environment. The outbreak of itai-itai disease, which is the most severe stage of chronic Cd poisoning, occurred in the Cd-polluted Jinzu River basin in Toyama. In this area, the river was contaminated by slag from a mine upstream; as a consequence, the soil in rice paddies was polluted with heavy metals including Cd through irrigation water from around 1910 to the 1960s. The government of Toyama prefecture carried out an extensive survey on Cd concentration in rice and soil of the paddy fields and declared that the upper layer of a total of 1500 ha of paddy fields should be replaced by nonpolluted soil. Then, an intervention program of soil replacement in the polluted paddy fields was continually carried out from 1980 to 2011. As a result, Cd concentration in rice markedly decreased. The kidney is the organ critically affected after long-term exposure to Cd. Proximal tubular dysfunction (RTD) has been found among the inhabitants of the Jinzu River basin. The very recent report by the Environmental Agency in Japan in 2009 has disclosed that b2-microglobulinuria with RTD is still found at a high prevalence among the inhabitants of the Jinzu River basin of both sexes. Twenty patients with itai-itai disease (1 male and 19 females), who attended our hospital and received medical examination during 2000 to 2008, had applied for recognition as itai-itai disease patients to the government of Toyama prefecture. In this paper, the recent epidemiological and clinical features of itai-itai disease are discussed on the basis of a review of the cases of these 19 female patients.

  18. Associations of Low Environmental Exposure to Multiple Metals with Renal Tubular Impairment in Korean Adults

    PubMed Central

    Lim, Hyungryul; Lim, Ji-ae; Choi, Jong Hyuk; Kwon, Ho-jang; Ha, Mina; Kim, Heon; Park, Jung-duck

    2016-01-01

    Recently several studies reported that the renal toxicity of lead (Pb) and cadmium (Cd) may exist in even a low level exposure. In terms of the deterioration of tubular function, it affects the loss of divalent metals and leads to other complications, so renal tubular effect of heavy metals should be well managed. Considering the exposure to heavy metals in reality, it is hard to find the case that human is exposed to only one heavy metal. We designed a cross-sectional study using Korean Research Project on the Integrated Exposure Assessment (KRIEFS) data to investigate the renal effects of multiple metal exposure in general population. We used blood Pb and urinary Cd as exposure measures, and urinary N-acetyl-β-D-glucosaminidase (NAG) and β2-microglobulin (β2-MG) as renal tubular impairment outcome. We conducted linear regression to identify the association between each heavy metal and urinary NAG and β2-MG. And then, we conducted linear regression including the interaction term. Of 1953 adults in KRIEFS (2010~2011), the geometric mean of blood Pb and urinary Cd concentration was 2.21 μg/dL (geometric SD = 1.49 μg/dL) and 1.08 μg/g cr (geometric SD = 1.98 μg/g cr), respectively. In urinary Cd, the strength of the association was also high after adjusting (urinary NAG: β = 0.44, p < 0.001; urinary β2-MG: β = 0.13, p = 0.002). Finally, we identified the positive interactions for the two renal biomarkers. The interaction effect of the two heavy metals of β2-MG was greater than that of NAG. It is very important in public health perspective if the low level exposure to multiple heavy metals has an interaction effect on kidney. More epidemiological studies for the interaction and toxicological studies on the mechanism are needed. PMID:26977259

  19. Effect of angiotensin II and captopril on renal tubular function in man.

    PubMed Central

    Düsing, R; Moritz, J; Glänzer, K; Kramer, H J

    1985-01-01

    The effects of nonpressor doses of intravenous angiotensin II and of the converting enzyme inhibitor captopril on renal excretory function were investigated in eight healthy volunteers during sustained water diuresis on a constant intake of 150 mmol sodium per day. The angiotensin II-analogue val5-angiotensin II-asp1-beta-amide was infused i.v. at an average dose of 2.6 ng kg-1 min-1 which was the highest dose without a significant effect on arterial blood pressure. This subpressor dose of angiotensin II significantly decreased urine volume, urinary excretion of sodium, chloride and phosphate and distal delivery [(CH2O + CCl)/GFR X 100] in the absence of changes in GFR or distal fractional chloride absorption [CH2O/(CH2O + CCl)]. In a second series of experiments, an oral dose of 50 mg of the angiotensin I-converting enzyme inhibitor captopril was given to the sodium replete volunteers. In this study, captopril did not affect arterial blood pressure, GFR or any of the determined parameters of renal tubular function. Our results strongly suggest that the nonpressor dose of angiotensin II induced renal retention of sodium chloride via increased absorption in the proximal tubule. Thus, they further support the concept that angiotensin II participates in the regulation of renal sodium chloride excretion by affecting proximal tubular absorptive capacity. However, in the sodium replete stage, angiotensin II is of no major importance in regulating sodium chloride excretion. PMID:3884028

  20. Effect of low-osmolar contrast medium iopromide and iso-osmolar iodixanol on DNA fragmentation in renal tubular cell culture.

    PubMed

    Ludwig, Ulla; Connemann, Julia; Keller, Frieder

    2013-12-01

    Intravascular administration of iodinated contrast media continues to be a common cause of hospital-acquired acute kidney injury. Accumulating evidence suggests that radiocontrast agent-induced nephrotoxicity is associated with increased oxidative stress, which leads to renal tissue damage with DNA fragmentation. We therefore tested whether an iso-osmolar contrast medium (iodixanol) causes less oxidative DNA damage to renal tubular cells than a low-osmolar contrast medium (iopromide). HK-2 cells (human proximal renal tubular cell line) were incubated at different time points (10 min-2 h) with increasing concentrations (20-120 mg/ml iodine) of iodixanol or of iopromide. Oxidative DNA damage to renal tubular cells was measured by alkaline comet assay (single-cell gel electrophoresis). Both iso- and low-osmolar contrast agents induced time- and concentration-dependent DNA fragmentation. DNA fragmentation was maximal at 2 h with 120 mg/ml iodine for iopromide (32 ± 27 tail moments) and iodixanol (46 ± 41 tail moments); both were significantly different from the control value with 3.15 ± 1.6 tail moments (Student's t test; p < 0.001). After 1 and 2 h and for all concentrations, iodixanol produced significantly higher DNA fragmentation than iopromide (ANOVA for 1 h p = 0.039 and 2 h p = 0.025, respectively). We were able to demonstrate for the first time that an iso-osmolar contrast medium induced even greater oxidative stress and DNA damage than a low-osmolar agent in HK-2 cells. This could provide an explanation for the nephrotoxicity that also is observed with iodixanol in clinical practice.

  1. Polycystin-1 binds Par3/aPKC and controls convergent extension during renal tubular morphogenesis

    NASA Astrophysics Data System (ADS)

    Castelli, Maddalena; Boca, Manila; Chiaravalli, Marco; Ramalingam, Harini; Rowe, Isaline; Distefano, Gianfranco; Carroll, Thomas; Boletta, Alessandra

    2013-10-01

    Several organs, including the lungs and kidneys, are formed by epithelial tubes whose proper morphogenesis ensures correct function. This is best exemplified by the kidney, where defective establishment or maintenance of tubular diameter results in polycystic kidney disease, a common genetic disorder. Most polycystic kidney disease cases result from loss-of-function mutations in the PKD1 gene, encoding Polycystin-1, a large receptor of unknown function. Here we demonstrate that PC-1 has an essential role in the establishment of correct tubular diameter during nephron development. Polycystin-1 associates with Par3 favouring the assembly of a pro-polarizing Par3/aPKC complex and it regulates a programme of cell polarity important for oriented cell migration and for a convergent extension-like process during tubular morphogenesis. Par3 inactivation in the developing kidney results in defective convergent extension and tubular morphogenesis, and in renal cyst formation. Our data define Polycystin-1 as central to cell polarization and to epithelial tube morphogenesis and homeostasis.

  2. Involvement of caspase-12-dependent apoptotic pathway in ionic radiocontrast urografin-induced renal tubular cell injury

    SciTech Connect

    Wu, Cheng Tien; Weng, Te I.; Chen, Li Ping; Chiang, Chih Kang; Liu, Shing Hwa

    2013-01-01

    Contrast medium (CM) induces a direct toxic effect on renal tubular cells. This toxic effect subjects in the disorder of CM-induced nephropathy. Our previous work has demonstrated that CM shows to activate the endoplasmic reticulum (ER)-related adaptive unfolding protein response (UPR) activators. Glucose-regulated protein 78 (GRP78)/eukaryotic initiation factor 2α (eIF2α)-related pathways play a protective role during the urografin (an ionic CM)-induced renal tubular injury. However, the involvement of ER stress-related apoptotic signals in the urografin-induced renal tubular cell injury remains unclear. Here, we examined by the in vivo and in vitro experiments to explore whether ER stress-regulated pro-apoptotic activators participate in urografin-induced renal injury. Urografin induced renal tubular dilation, tubular cells detachment, and necrosis in the kidneys of rats. The tubular apoptosis, ER stress-related pro-apoptotic transcriptional factors, and kidney injury marker-1 (kim-1) were also conspicuously up-regulated in urografin-treated rats. Furthermore, treatment of normal rat kidney (NRK)-52E tubular cells with urografin augmented the expressions of activating transcription factor-6 (ATF-6), C/EBP homologous protein (CHOP), Bax, caspase-12, JNK, and inositol-requiring enzyme (IRE) 1 signals. Urografin-induced renal tubular cell apoptosis was not reversed by the inhibitors of ATF-6, JNK signals or CHOP siRNA transfection, but it could be partially reversed by the inhibitor of caspase-12. Taken together, the present results and our previous findings suggest that exposure of CM/urografin activates the ER stress-regulated survival- and apoptosis-related signaling pathways in renal tubular cells. Caspase-12-dependent apoptotic pathway may be partially involved in the urografin-induced nephropathy. -- Highlights: ► Ionic contrast medium-urografin induces renal tubular cell apoptosis. ► Urografin induces the ER stress-regulated survival and apoptosis

  3. p38 MAPK mediates renal tubular cell TNF-alpha production and TNF-alpha-dependent apoptosis during simulated ischemia.

    PubMed

    Meldrum, K K; Meldrum, D R; Hile, K L; Yerkes, E B; Ayala, A; Cain, M P; Rink, R C; Casale, A J; Kaefer, M A

    2001-08-01

    Ischemia causes renal tubular cell loss through apoptosis; however, the mechanisms of this process remain unclear. Using the renal tubular epithelial cell line LLC-PK(1), we developed a model of simulated ischemia (SI) to investigate the role of p38 MAPK (mitogen-activated protein kinase) in renal cell tumor necrosis factor-alpha (TNF-alpha) mRNA production, protein bioactivity, and apoptosis. Results demonstrate that 60 min of SI induced maximal TNF-alpha mRNA production and bioactivity. Furthermore, 60 min of ischemia induced renal tubular cell apoptosis at all substrate replacement time points examined, with peak apoptotic cell death occurring after either 24 or 48 h. p38 MAPK inhibition abolished TNF-alpha mRNA production and TNF-alpha bioactivity, and both p38 MAPK inhibition and TNF-alpha neutralization (anti-porcine TNF-alpha antibody) prevented apoptosis after 60 min of SI. These results constitute the initial demonstration that 1) renal tubular cells produce TNF-alpha mRNA and biologically active TNF-alpha and undergo apoptosis in response to SI, and 2) p38 MAPK mediates renal tubular cell TNF-alpha production and TNF-alpha-dependent apoptosis after SI.

  4. Acquired nephrogenic diabetes insipidus secondary to distal renal tubular acidosis and nephrocalcinosis associated with Sjögren's syndrome.

    PubMed

    Nagayama, Y; Shigeno, M; Nakagawa, Y; Suganuma, A; Takeshita, A; Fujiyama, K; Ashizawa, K; Kiriyama, T; Yokoyama, N; Nagataki, S

    1994-09-01

    A 52-year-old woman was referred to our hospital because of 16-year history of polyuria and polydipsia. Hyposthenuria, hyperchloremic metabolic acidosis and the inabilities to acidify the urine after acid-loading test and to concentrate the urine in responses to water-deprivation and antidiuretic hormone administration allowed us to diagnose renal tubular acidosis and nephrogenic diabetes insipidus. Radiographic examinations revealed bilateral nephrocalcinosis. The patient was also found to have clinical and laboratory findings characteristic for Sjögren's syndrome. Thus the longstanding, poorly monitored distal renal tubular acidosis associated with Sjögren's syndrome was considered to result in very rare renal complications-nephrocalcinosis and nephrogenic diabetes insipidus. In patients with renal tubular acidosis and/or nephrogenic diabetes insipidus of unknown etiology, therefore, Sjögren's syndrome should be considered as one of primary disorders.

  5. Nitric Oxide Is an Important Mediator of Renal Tubular Epithelial Cell Death in Vitro and in Murine Experimental Hydronephrosis

    PubMed Central

    Kipari, Tiina; Cailhier, Jean-Francois; Ferenbach, David; Watson, Simon; Houlberg, Kris; Walbaum, David; Clay, Spike; Savill, John; Hughes, Jeremy

    2006-01-01

    Macrophages play a pivotal role in tissue injury and fibrosis during renal inflammation. Although macrophages may induce apoptosis of renal tubular epithelial cells, the mechanisms involved are unclear. We used a microscopically quantifiable co-culture assay to dissect the cytotoxic interaction between murine bone marrow-derived macrophages and Madin-Darby canine kidney cells and primary murine renal tubular epithelial cells. The induction of tubular cell apoptosis by cytokine-activated macrophages was reduced by inhibitors of nitric oxide synthase whereas tubular cell proliferation was unaffected. Furthermore, cytokine-activated macrophages derived from mice targeted for the deletion of inducible nitric oxide synthase were noncytotoxic. We then examined the role of nitric oxide in vivo by inhibiting inducible nitric oxide synthase in the model of murine experimental hydronephrosis. l-N6-(1-iminoethyl)-lysine was administered in the drinking water between days 5 and 7 after ureteric obstruction. Macrophage infiltration was comparable between groups, but treatment significantly inhibited tubular cell apoptosis at day 7. Tubular cell proliferation was unaffected. Inducible nitric oxide synthase blockade also reduced interstitial cell apoptosis and increased collagen III deposition. These data indicate that nitric oxide is a key mediator of macrophage-directed tubular cell apoptosis in vitro and in vivo and also modulates tubulointerstitial fibrosis. PMID:16877341

  6. Autophagy activation protects shock wave induced renal tubular epithelial cell apoptosis may through modulation of Akt/ GSK-3β pathway.

    PubMed

    Long, Qingzhi; Li, Xiang; He, Hui; He, Dalin

    2016-01-01

    Extracorporeal shock wave lithotripsy (ESWL) is well documented to exert destructive effect to renal cells and its mechanism is not clear. Autophagy is one of cell basic response for stressful conditions and it is important to determine cell's fate. The aim of this study is to elucidate the role of autophagy in the process of shock wave-induced renal cells injury. NRK-52E cell, a rat renal tubular epithelial cell, was exposed to shock wave at the voltage of 14KV. GFP-LC3 puncta was used to monitor Autophagy flux in the process of shock wave injury. Autophagic relative proteins, such as light chain 3 (LC3), beclin-1 and p62, were also examined. Cell variability and apoptosis were detected when inhibition autophagy with 3-methyladenine (3MA) or stimulating its activity with rapamycin during the process of shock wave injury. The role of Akt/ GSK-3β and its connection with autophagy in the process of shock wave injury were also investigated. Shock wave was confirmed to activate autophagy in renal cells, which was manifested in LC3-II turnover, beclin-1 induction and degradation of p62. Inhibition autophagy enhanced cell damage or apoptosis, whereas its stimulating was able to exert protection from shock wave injury. Akt/ GSK-3β, a cell-survival signaling pathway, can also be activated during the process. And its activation could be suppressed by blockade autophagy. Autophagy is a self-protective response for renal cells from shock wave injury. The cyto-protection of autophagy may be connected with modulation Akt/ GSK-3β pathway.

  7. Autophagy activation protects shock wave induced renal tubular epithelial cell apoptosis may through modulation of Akt/ GSK-3β pathway

    PubMed Central

    Long, Qingzhi; Li, Xiang; He, Hui; He, Dalin

    2016-01-01

    Purpose: Extracorporeal shock wave lithotripsy (ESWL) is well documented to exert destructive effect to renal cells and its mechanism is not clear. Autophagy is one of cell basic response for stressful conditions and it is important to determine cell's fate. The aim of this study is to elucidate the role of autophagy in the process of shock wave-induced renal cells injury. Methods: NRK-52E cell, a rat renal tubular epithelial cell, was exposed to shock wave at the voltage of 14KV. GFP-LC3 puncta was used to monitor Autophagy flux in the process of shock wave injury. Autophagic relative proteins, such as light chain 3 (LC3), beclin-1 and p62, were also examined. Cell variability and apoptosis were detected when inhibition autophagy with 3-methyladenine (3MA) or stimulating its activity with rapamycin during the process of shock wave injury. The role of Akt/ GSK-3β and its connection with autophagy in the process of shock wave injury were also investigated. Results: Shock wave was confirmed to activate autophagy in renal cells, which was manifested in LC3-II turnover, beclin-1 induction and degradation of p62. Inhibition autophagy enhanced cell damage or apoptosis, whereas its stimulating was able to exert protection from shock wave injury. Akt/ GSK-3β, a cell-survival signaling pathway, can also be activated during the process. And its activation could be suppressed by blockade autophagy. Conclusion: Autophagy is a self-protective response for renal cells from shock wave injury. The cyto-protection of autophagy may be connected with modulation Akt/ GSK-3β pathway. PMID:27994511

  8. Proximal renal tubular function in myelomatosis: observations in the fourth Medical Research Council trial.

    PubMed Central

    Cooper, E H; Forbes, M A; Crockson, R A; MacLennan, I C

    1984-01-01

    Proximal renal tubular function was studied in 522 consecutive patients entered into the Medical Research Council's fourth myelomatosis trial. Assessment was made at presentation after a 48 h period of hydration but before administration of chemotherapy. The most common abnormalities in the urine other than light chain proteinuria were raised concentrations of the low molecular weight proteins alpha 1-microglobulin and alpha 1-acid glycoprotein. These were usually accompanied by increases in urinary beta-N-acetyl-D-glucosaminidase concentrations. The concentration of these substances in the urine directly correlated with urinary free light chain output. This tubular proteinuria was seen whether or not patients had impaired glomerular function, as assessed by a rise in serum creatinine concentration. Urinary concentrations of retinol binding protein, however, were generally increased only when serum creatinine concentrations were raised. This applied even when there were high concentrations of light chains, alpha 1-microglobulin, alpha 1-acid glycoprotein, and beta-N-acetyl-D-glucosaminidase in the urine. There is therefore a selective tubular proteinuria in myelomatosis which is seen in almost all patients with urinary light chain values greater than 1 u/l. This proteinuria is generally reversible, when light chains no longer appear in the urine. Patients whose serum creatinine was greater than 200 mumol/l, however, had increased urinary output of retinol binding protein in addition to increased excretion of alpha 1-microglobulin, alpha 1-acid glycoprotein, and beta-N-acetyl-D-glucosaminidase. Tubular proteinuria in many of these patients presenting in renal failure persisted even when light chain output was reduced after chemotherapy. PMID:6206095

  9. Fenofibrate reduces cisplatin-induced apoptosis of renal proximal tubular cells via inhibition of JNK and p38 pathways.

    PubMed

    Thongnuanjan, Penjai; Soodvilai, Sirima; Chatsudthipong, Varanuj; Soodvilai, Sunhapas

    2016-01-01

    Cisplatin is widely used as a standard chemotherapy for solid tumors. The major adverse effect of cisplatin is nephrotoxicity in proximal tubular cells, via oxidative stress, DNA damage, cell apoptosis, and inflammation. The aim of this study was to investigate the pharmacological effect and mechanism of fibrate drugs on cisplatin-induced renal proximal tubular cell death. Cisplatin decreased cell viability of LLC-PK1 and HK-2 cells in a dose-dependent manner. Cisplatin-induced apoptosis was attenuated by co-treatment with fenofibrate while less so with clofibrate and bezafibrate. Fenofibrate's protective effect was not complimented by co-treatment with GW6471, a PPARα antagonist, indicating the protective effect occurred via a PPARα-independent mechanism. Treating cells with cisplatin induced reactive oxygen species (ROS), c-JUN N-terminal kinase (JNK), and p38 kinase (p38), but not extracellular signal-regulated kinase (ERK). Fenofibrate reversed cisplatin-induced JNK and p38 activation, but had no effect on ROS production. The findings suggest fenofibrate's protective effect on cisplatin-induced cytotoxicity is mediated by inhibition of JNK and p38. Moreover, fenofibrate did not alter cisplatin's antitumor effect on cancer cell lines including T84, SW-480, HepG2, and SK-LU-1 cells. Therefore, fenofibrate may be a candidate agent for further development as an adjuvant to cisplatin treatment.

  10. Pediatric Sjogren syndrome with distal renal tubular acidosis and autoimmune hypothyroidism: an uncommon association.

    PubMed

    Agarwal, Amit; Kumar, Pradeep; Gupta, Nomeeta

    2015-11-01

    A 14-year-old female came with the history of sudden onset weakness; during work up, she was found to have hyperchloremic metabolic acidosis with normal anion gap and normal renal function suggesting the possibility of renal tubular acidosis (RTA). On further evaluation of RTA, she had positive antinuclear antibody, anti-Ro, and anti-La antibodies. On nuclear scan of salivary glands, her left parotid gland was nonfunctional. Her parotid biopsy revealed dilated interlobular ducts engulfed by lymphoid cells. She also had autoimmune hypothyroidism as suggested by raised TSH and positive anti-TPO antibodies. At admission, her serum potassium levels were low and she was treated with intravenous potassium chloride. After she recovered from acute hypokalemic paralysis, she was started on oral potassium citrate along with phosphate supplements, hydroxychloroquine, oral prednisolone and thyroxine supplements. Over the next 6 months, she has significant reduction in the dosage of potassium, bicarbonate and phosphate and gained 3 kg of weight and 3.5 cm of height. As primary Sjogren syndrome itself is rare in pediatric population and its association with renal tubular acidosis is even rarer, we suggest considering Sjogren syndrome as a differential diagnosis during the RTA work-up is worth trying.

  11. Effect of taurine on advanced glycation end products-induced hypertrophy in renal tubular epithelial cells

    SciTech Connect

    Huang, J.-S. Chuang, L.-Y.; Guh, J.-Y.; Yang, Y.-L.; Hsu, M.-S.

    2008-12-01

    Mounting evidence indicates that advanced glycation end products (AGE) play a major role in the development of diabetic nephropathy (DN). Taurine is a well documented antioxidant agent. To explore whether taurine was linked to altered AGE-mediated renal tubulointerstitial fibrosis in DN, we examined the molecular mechanisms of taurine responsible for inhibition of AGE-induced hypertrophy in renal tubular epithelial cells. We found that AGE (but not non-glycated BSA) caused inhibition of cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, bcl-2 protein expression, and mitochondrial cytochrome c release in BSA, AGE, or the antioxidant taurine treatments in these cells. AGE-induced the Raf-1/extracellular signal-regulated kinase (ERK) activation was markedly blocked by taurine. Furthermore, taurine, the Raf-1 kinase inhibitor GW5074, and the ERK kinase inhibitor PD98059 may have the ability to induce cellular proliferation and cell cycle progression from AGE-treated cells. The ability of taurine, GW5074, or PD98059 to inhibit AGE-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of RAGE, p27{sup Kip1}, collagen IV, and fibronectin. The results obtained in this study suggest that taurine may serve as the potential anti-fibrotic activity in DN through mechanism dependent of its Raf-1/ERK inactivation in AGE-induced hypertrophy in renal tubular epithelial cells.

  12. Tubular kidney damage and centrilobular liver injury after intratracheal instillation of dimethyl selenide.

    PubMed

    Cherdwongcharoensuk, Duangrudee; Henrique, Rui; Upatham, Suchart; Pereira, António Sousa; Aguas, Artur P

    2005-01-01

    Accidental inhalation of selenium (Se) derivatives, such as dimethyl selenide (DMSe), has been associated with damage of respiratory tissues. However, systemic effects of inhaled Se have not been thoroughly established. We have investigated whether mouse kidney and liver show cellular pathology as a result of a single intratracheal instillation of two different doses of DMSe (0.05 and 0.1 mg Se/kg BW). The animals were sacrificed 1, 7, 14, and 28 days after either 1 of the 2 DMSe treatments; samples were studied by light microscopy. Instillation of the low DMSe dose resulted in acute and transient tubular disease of the kidney expressed by swelling and vacuolation of epithelial cells of proximal tubules; in some mice, tubular necrosis was observed. After 14 days of the DMSe treatment, these lesions were ameliorated and, by day 28, the kidney tubular epithelium depicted a normal morphology. The same low dose of DMSe caused sustained damage to centrilobular hepatocytes characterized by swollen and vacuolized liver cells. After the instillation of the high DMSe dose, the mice presented sustained liver and kidney focal necrosis. Our data suggest that inhalation of DMSe results in: (i) acute tubular injury of the kidney and damage to centrilobular liver cells and (ii) this systemic pathology induced by DMSe is a dose-dependent phenomenon.

  13. Competitive inhibition of renal tubular secretion of ciprofloxacin and metabolite by probenecid

    PubMed Central

    Landersdorfer, Cornelia B; Kirkpatrick, Carl M J; Kinzig, Martina; Bulitta, Jürgen B; Holzgrabe, Ulrike; Jaehde, Ulrich; Reiter, Andreas; Naber, Kurt G; Rodamer, Michael; Sörgel, Fritz

    2010-01-01

    AIMS Probenecid influences transport processes of drugs at several sites in the body and decreases elimination of several quinolones. We sought to explore extent, time course, and mechanism of the interaction between ciprofloxacin and probenecid at renal and nonrenal sites. METHODS A randomized, two-way crossover study was conducted in 12 healthy volunteers (in part previously published Clin Pharmacol Ther 1995; 58: 532–41). Subjects received 200 mg ciprofloxacin as 30-min intravenous infusion without and with 3 g probenecid divided into five oral doses. Drug concentrations were analysed by liquid chromatography–tandem mass spectrometry and high-performance liquid chromatography. Ciprofloxacin and its 2-aminoethylamino-metabolite (M1) in plasma and urine with and without probenecid were modelled simultaneously with WinNonlin®. RESULTS Data are ratio of geometric means (90% confidence intervals). Addition of probenecid reduced the median renal clearance from 23.8 to 8.25 l h−1[65% reduction (59, 71), P < 0.01] for ciprofloxacin and from 20.5 to 8.26 l h−1 (66% reduction (57, 73), P < 0.01] for M1 (estimated by modelling). Probenecid reduced ciprofloxacin nonrenal clearance by 8% (1, 14) (P < 0.08). Pharmacokinetic modelling indicated competitive inhibition of the renal tubular secretion of ciprofloxacin and M1 by probenecid. The affinity for the renal transporter was 4.4 times higher for ciprofloxacin and 3.6 times higher for M1 than for probenecid, based on the molar ratio. Probenecid did not affect volume of distribution of ciprofloxacin or M1, nonrenal clearance or intercompartmental clearance of ciprofloxacin. CONCLUSIONS Probenecid inhibited the renal tubular secretion of ciprofloxacin and M1, probably by a competitive mechanism and due to reaching >100-fold higher plasma concentrations. Formation of M1, nonrenal clearance and distribution of ciprofloxacin were not affected. PMID:20233180

  14. Calcium oxalate monohydrate crystals internalized into renal tubular cells are degraded and dissolved by endolysosomes.

    PubMed

    Chaiyarit, Sakdithep; Singhto, Nilubon; Thongboonkerd, Visith

    2016-02-25

    Interaction between calcium oxalate crystals and renal tubular cells has been recognized as one of the key mechanisms for kidney stone formation. While crystal adhesion and internalization have been extensively investigated, subsequent phenomena (i.e. crystal degradation and dissolution) remained poorly understood. To explore these mechanisms, we used fluorescein isothiocyanate (FITC)-labelled calcium oxalate monohydrate (COM) crystals (1000 μg/ml of crystals/culture medium) to confirm crystal internalization into MDCK (Type II) renal tubular cells after exposure to the crystals for 1 h and to trace the internalized crystals. Crystal size, intracellular and extracellular fluorescence levels were measured using a spectrofluorometer for up to 48 h after crystal internalization. Moreover, markers for early endosome (Rab5), late endosome (Rab7) and lysosome (LAMP-2) were examined by laser-scanning confocal microscopy. Fluorescence imaging and flow cytometry confirmed that FITC-labelled COM crystals were internalized into MDCK cells (14.83 ± 0.85%). The data also revealed a reduction of crystal size in a time-dependent manner. In concordance, intracellular and extracellular fluorescence levels were decreased and increased, respectively, indicating crystal degradation/dissolution inside the cells and the degraded products were eliminated extracellularly. Moreover, Rab5 and Rab7 were both up-regulated and were also associated with the up-regulated LAMP-2 to form large endolysosomes in the COM-treated cells at 16-h after crystal internalization. We demonstrate herein, for the first time, that COM crystals could be degraded/dissolved by endolysosomes inside renal tubular cells. These findings will be helpful to better understand the crystal fate and protective mechanism against kidney stone formation. Copyright © 2016. Published by Elsevier Ireland Ltd.

  15. Effects of "in vivo" administration of baclofen on rat renal tubular function.

    PubMed

    Donato, Verónica; Pisani, Gerardo Bruno; Trumper, Laura; Monasterolo, Liliana Alicia

    2013-09-05

    The effects of the in vivo administration of baclofen on renal tubular transport and aquaporin-2 (AQP2) expression were evaluated. In conscious animals kept in metabolic cages, baclofen (0.01-1mg/kg, s.c.) induced a dose-dependent increment in the urine flow rate (UFR) and in sodium and potassium excretion, associated with an increased osmolal clearance (Closm), a diminished urine to plasma osmolality ratio (Uosm/Posm) and a decrease in AQP2 expression. The above mentioned baclofen effects on functional parameters were corroborated by using conventional renal clearance techniques. Additionally, this model allowed the detection of a diminution in glucose reabsorption. Some experiments were performed with water-deprived or desmopressin-treated rats kept in metabolic cages. Either water deprivation or desmopressin treatment decreased the UFR and increased the Uosm/Posm. Baclofen did not change the Uosm/Posm or AQP2 expression in desmopressin-treated rats; but it increased the UFR and diminished the Uosm/Posm and AQP2 expression in water-deprived animals. These results indicate that in vivo administration of baclofen promotes alterations in proximal tubular transport, since glucose reabsorption was decreased. The distal tubular function was also affected. The increased Closm indicates an alteration in solute reabsorption at the ascending limb of the Henle's loop. The decreased Uosm/Posm and AQP2 expression in controls and in water-deprived, but not in desmopressin-treated rats, lead us to speculate that some effect of baclofen on endogenous vasopressin availability could be responsible for the impaired urine concentrating ability, more than any disturbance in the responsiveness of the renal cells to the hormone.

  16. Downregulation of miR-205 Modulates Cell Susceptibility to Oxidative and Endoplasmic Reticulum Stresses in Renal Tubular Cells

    PubMed Central

    Muratsu-Ikeda, Shiyo; Nangaku, Masaomi; Ikeda, Yoichiro; Tanaka, Tetsuhiro; Wada, Takehiko; Inagi, Reiko

    2012-01-01

    Background Oxidative stress and endoplasmic reticulum (ER) stress play a crucial role in tubular damage in both acute kidney injury (AKI) and chronic kidney disease (CKD). While the pathophysiological contribution of microRNAs (miRNA) to renal damage has also been highlighted, the effect of miRNA on renal damage under oxidative and ER stresses conditions remains elusive. Methods We assessed changes in miRNA expression in the cultured renal tubular cell line HK-2 under hypoxia-reoxygenation-induced oxidative stress or ER stress using miRNA microarray assay and real-time RT-PCR. The pathophysiological effect of miRNA was evaluated by cell survival rate, intracellular reactive oxygen species (ROS) level, and anti-oxidant enzyme expression in miRNA-inhibited HK-2 or miRNA-overexpressed HK-2 under these stress conditions. The target gene of miRNA was identified by 3′-UTR-luciferase assay. Results We identified 8 and 10 miRNAs whose expression was significantly altered by oxidative and ER stresses, respectively. Among these, expression of miR-205 was markedly decreased in both stress conditions. Functional analysis revealed that decreased miR-205 led to an increase in cell susceptibility to oxidative and ER stresses, and that this increase was associated with the induction of intracellular ROS and suppression of anti-oxidant enzymes. While increased miR-205 by itself made no change in cell growth or morphology, cell viability under oxidative or ER stress conditions was partially restored. Further, miR-205 bound to the 3′-UTR of the prolyl hydroxylase 1 (PHD1/EGLN2) gene and suppressed the transcription level of EGLN2, which modulates both intracellular ROS level and ER stress state. Conclusions miR-205 serves a protective role against both oxidative and ER stresses via the suppression of EGLN2 and subsequent decrease in intracellular ROS. miR-205 may represent a novel therapeutic target in AKI and CKD associated with oxidative or ER stress in tubules. PMID:22859986

  17. Comparison of four decontamination treatments on porcine renal decellularized extracellular matrix structure, composition, and support of human renal cortical tubular epithelium cells.

    PubMed

    Poornejad, Nafiseh; Nielsen, Jeffery J; Morris, Ryan J; Gassman, Jason R; Reynolds, Paul R; Roeder, Beverly L; Cook, Alonzo D

    2016-03-01

    Engineering whole organs from porcine decellularized extracellular matrix and human cells may lead to a plentiful source of implantable organs. Decontaminating the porcine decellularized extracellular matrix scaffolds is an essential step prior to introducing human cells. However, decontamination of whole porcine kidneys is a major challenge because the decontamination agent or irradiation needs to diffuse deep into the structure to eliminate all microbial contamination while minimizing damage to the structure and composition of the decellularized extracellular matrix. In this study, we compared four decontamination treatments that could be applicable to whole porcine kidneys: 70% ethanol, 0.2% peracetic acid in 1 M NaCl, 0.2% peracetic acid in 4% ethanol, and gamma (γ)-irradiation. Porcine kidneys were decellularized by perfusion of 0.5% (w/v) aqueous solution of sodium dodecyl sulfate and the four decontamination treatments were optimized using segments (n = 60) of renal tissue to ensure a consistent comparison. Although all four methods were successful in decontamination, γ-irradiation was very damaging to collagen fibers and glycosaminoglycans, leading to less proliferation of human renal cortical tubular epithelium cells within the porcine decellularized extracellular matrix. The effectiveness of the other three optimized solution treatments were then all confirmed using whole decellularized porcine kidneys (n = 3). An aqueous solution of 0.2% peracetic acid in 1 M NaCl was determined to be the best method for decontamination of porcine decellularized extracellular matrix.

  18. Primary sclerosing cholangitis: a new cause of distal renal tubular acidosis

    PubMed Central

    Goutaudier, Valentin; Szwarc, Ilan; Serre, Jean-Emmanuel; Pageaux, Georges-Philippe; Argilés, Àngel

    2016-01-01

    We describe the first case of distal renal tubular acidosis (dRTA) associated with primary sclerosing cholangitis. A 26-year-old Lao-Thai male patient presented with severe jaundice, metabolic acidosis and hypokalaemia. He was diagnosed of dRTA. Liver transplantation resulted in correction of electrolyte disturbances and hyperbilirubinaemia. A fludrocortisone-furosemide test revealed normal urinary acidification, demonstrating no residual dRTA. This observation suggests that dRTA may be an early manifestation of bilirubin-associated nephropathy or the consequence of an immune mechanism. PMID:27994859

  19. A novel neurological disorder with progressive CNS calcification, deafness, renal tubular acidosis, and microcytic anemia.

    PubMed

    Yoshimura, M; Hara, T; Maegaki, Y; Koeda, T; Okubo, K; Hamasaki, N; Sly, W S; Takeshita, K

    1997-03-01

    Progressive calcification of the brain and the spinal cord at early infantile onset was observed in two siblings. They showed growth failure, psychomotor deterioration, deafness, vestibular dysfunction, microcytic hypochromic anemia, abnormal ratios of lymphocyte subpopulations, and slightly decreased bicarbonate on blood gas analysis. Distal renal tubular acidosis was demonstrated in one of them. Carbonic anhydrase II activity was normal. This new hereditary disease might have a defect in a molecule that is present in brain, spinal cord, kidney and hematocytes and is involved in H+/HCO3- production or transport.

  20. Anesthetic Management of a Surgical Patient with Chronic Renal Tubular Acidosis Complicated by Subclinical Hypothyroidism

    PubMed Central

    Yamazaki, Haruyuki; Yasumura, Rie; Wada, Kosuke

    2016-01-01

    A 53-year-old man with chronic renal tubular acidosis and subclinical hypothyroidism underwent lower leg amputation surgery under general anesthesia. Perioperative acid-base management in such patients poses many difficulties because both pathophysiologies have the potential to complicate the interpretation of capnometry and arterial blood gas analysis data; inappropriate correction of chronic metabolic acidosis may lead to postoperative respiratory deterioration. We discuss the management of perioperative acidosis in order to achieve successful weaning from mechanical ventilation and promise a complete recovery from anesthesia. PMID:27648310

  1. Severe hypophosphatemic osteomalacia with Fanconi syndrome, renal tubular acidosis, vitamin D deficiency and primary biliary cirrhosis.

    PubMed

    Bando, Hironori; Hashimoto, Naoko; Hirota, Yushi; Sakaguchi, Kazuhiko; Hisa, Itoko; Inoue, Yoshifumi; Imanishi, Yasuo; Seino, Susumu; Kaji, Hiroshi

    2009-01-01

    A 49-year-old woman was admitted to our hospital for back pain with marked thoracic and extremity deformities leading to bed-rest for three years. She was diagnosed with hypophosphatemic osteomalacia based on her symptoms, X-ray and bone scintigram, high serum alkaline phosphatase level, and low serum levels of both phosphorus and 1,25 dihydroxyvitamin D(3) with inhibition of phosphorus reabsorption. Fanconi syndrome with renal tubular acidosis, vitamin D deficiency and primary biliary cirrhosis were related to the pathogenesis of osteomalacia in this case. Several causal diseases may be concomitantly responsible for acceleration of the severity of osteomalacia in this patient.

  2. [Distal renal tubular acidosis with rhabdomyolysis as the presenting form in 4 pregnant women].

    PubMed

    Carminati, G; Chena, A; Orlando, J M; Russo, S; Salomón, S; Carena, J A

    2001-01-01

    We describe four pregnant patients with distal renal tubular acidosis (type I) (DRTA) whose initial presentation was rhabdomyolysis (RML) secondary to severe hypokalemia. We draw attention to the unusual presentation of DRTA during pregnancy, the low frequency of DRTA in adult patients and RML as initial manifestation. In one case the DRTA was secondary to Sjögren Syndrome and the etiology was unknown in the rest of the cases. We discuss the potential pathogenic mechanisms to explain hypokalemic RML and the various causes of DRTA in adult patients.

  3. Mechanisms of Inflammatory Injury of Renal Tubular Cells in a Cellular Model of Pyelonephritis.

    PubMed

    Morosanova, M A; Plotnikov, E Y; Zorova, L D; Pevzner, I B; Popkov, V A; Silachev, D N; Jankauskas, S S; Babenko, V A; Zorov, D B

    2016-11-01

    Previously, we have assembled a cellular model of pyelonephritis which contains a primary culture of renal tubular epithelial cells, mononuclear leukocytes, and bacterial lysate or lipopolysaccharide. After cocultivation of renal cells with leukocytes and bacterial lysate, proinflammatory changes were observed in the renal cells, followed by nitrosative and oxidative stress and cell death. The interaction of bacterial antigens not only with leukocytes, but also with epithelial cells of the renal tubules, was partially mediated by signaling pathways involving Toll-like receptors (TLR2 and TLR4). Activation of these receptors led to increased levels of oxidative stress and synthesis of proinflammatory cytokines (TNF, IL-6, IL-1α) in the renal epithelium, while TLR4 blockade decreased the severity of these processes. Apart from the fact that activation of inflammatory signaling in response to bacterial antigens is observed directly in the renal cells, the presence of leukocytes significantly amplifies the inflammatory response as measured by the level of cytokines generated in the ensemble. In the presence of activated leukocytes, higher expression of TLR2 on the surface of renal cells was observed in response to exposure to bacterial components, which might explain the increased inflammatory response in the presence of leukocytes. The synthesis of IL-1α in the epithelial cells of the renal tubules in this inflammatory model leads to its accumulation in the nuclei, which has been reduced by the TLR4 antagonist polymyxin. TLR2 agonists also led to increased levels of IL-1α. The elevation in the content of IL-1α in nuclei was accompanied by increased acetylation of nuclear proteins, which has been reduced to control values after exposure to protective agents (Trolox, mitochondria-targeted antioxidant SkQR1 or LiCl). The high level of acetylation of histones is probably regulated by proinflammatory cytokines, and to some extent it is a marker of inflammation, which

  4. Metformin attenuates albumin-induced alterations in renal tubular cells in vitro.

    PubMed

    Allouch, Soumaya; Munusamy, Shankar

    2017-12-01

    Proteinuria (albuminuria) plays a crucial role in the etiology of chronic kidney disease (CKD) via alteration of multiple signaling pathways and cellular process in renal cells. The objectives of this study are to investigate the effects of activation of the energy-sensing molecule AMP-activated kinase (AMPK) in renal cells using metformin on endoplasmic reticulum (ER) stress, AKT, mTOR, epithelial-to-mesenchymal transition (EMT), autophagy, and apoptosis that are thought to mediate renal cell injury during proteinuria, and to dissect the AMPK- and non-AMPK mediated effects of metformin using an in vitro model of albumin-induced renal cell injury. Rat renal proximal tubular (NRK-52E) cells were exposed to 10 and 15 mg/ml of albumin for 72 h in the presence of 1 mM Metformin and/or 0.5 µM compound C, and assessed for alterations in the aforementioned pathways. Metformin treatment restored AMPK phosphorylation and augmented autophagy in renal cells exposed to albumin. In addition, metformin treatment attenuated the albumin-induced phosphorylation of AKT and the downstream targets of mTOR, and prevented albumin-mediated inductions of EMT marker (α-SMA), pro-apoptotic ER stress marker CHOP, and apoptotic caspases -12 and -3 in renal cells. Blockade of metformin-induced AMPK activation with compound C blunted the ER defense response and autophagy but had no effect on the markers of EMT and apoptosis in our model. Our studies suggest that metformin protects renal cells against proteinuric cytotoxicity via suppression of AKT and mTOR activation, inhibition of EMT and apoptosis, and augmentation of autophagy and ER defense response through AMPK-independent and AMPK-dependent mechanisms, respectively. © 2017 Wiley Periodicals, Inc.

  5. Ochratoxin A induced premature senescence in human renal proximal tubular cells.

    PubMed

    Yang, Xuan; Liu, Sheng; Huang, Chuchu; Wang, Haomiao; Luo, Yunbo; Xu, Wentao; Huang, Kunlun

    2017-05-01

    Ochratoxin A (OTA) has many nephrotoxic effects and is a promising compound for the study of nephrotoxicity. Human renal proximal tubular cells (HKC) are an important model for the study of renal reabsorption, renal physiology and pathology. Since the induction of OTA in renal senescence is largely unknown, whether OTA can induce renal senescence, especially at a sublethal dose, and the mechanism of OTA toxicity remain unclear. In our study, a sublethal dose of OTA led to an enhanced senescent phenotype, β-galactosidase staining and senescence associated secretory phenotype (SASP). Cell cycle arrest and cell shape alternations also confirmed senescence. In addition, telomere analysis by RT-qPCR allowed us to classify OTA-induced senescence as a premature senescence. Western blot assays showed that the p53-p21 and the p16-pRB pathways and the ezrin-associated cell spreading changes were activated during the OTA-induced senescence of HKC. In conclusion, our results demonstrate that OTA promotes the senescence of HKC through the p53-p21 and p16-pRB pathways. The understanding of the mechanisms of OTA-induced senescence is critical in determining the role of OTA in cytotoxicity and its potential carcinogenicity. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  6. Vasopressin Mediates the Renal Damage Induced by Limited Fructose Rehydration in Recurrently Dehydrated Rats.

    PubMed

    García-Arroyo, Fernando E; Tapia, Edilia; Blas-Marron, Mónica G; Gonzaga, Guillermo; Silverio, Octaviano; Cristóbal, Magdalena; Osorio, Horacio; Arellano-Buendía, Abraham S; Zazueta, Cecilia; Aparicio-Trejo, Omar Emiliano; Reyes-García, Juan G; Pedraza-Chaverri, José; Soto, Virgilia; Roncal-Jiménez, Carlos; Johnson, Richard J; Sánchez-Lozada, Laura G

    2017-01-01

    Recurrent dehydration and heat stress cause chronic kidney damage in experimental animals. The injury is exacerbated by rehydration with fructose-containing beverages. Fructose may amplify dehydration-induced injury by directly stimulating vasopressin release and also by acting as a substrate for the aldose reductase-fructokinase pathway, as both of these systems are active during dehydration. The role of vasopressin in heat stress associated injury has not to date been explored. Here we show that the amplification of renal damage mediated by fructose in thermal dehydration is mediated by vasopressin. Fructose rehydration markedly enhanced vasopressin (copeptin) levels and activation of the aldose reductase-fructokinase pathway in the kidney. Moreover, the amplification of the renal functional changes (decreased creatinine clearance and tubular injury with systemic inflammation, renal oxidative stress, and mitochondrial dysfunction) were prevented by the blockade of V1a and V2 vasopressin receptors with conivaptan. On the other hand, there are also other operative mechanisms when water is used as rehydration fluid that produce milder renal damage that is not fully corrected by vasopressin blockade. Therefore, we clearly showed evidence of the cross-talk between fructose, even at small doses, and vasopressin that interact to amplify the renal damage induced by dehydration. These data may be relevant for heat stress nephropathy as well as for other renal pathologies due to the current generalized consumption of fructose and deficient hydration habits.

  7. Vasopressin Mediates the Renal Damage Induced by Limited Fructose Rehydration in Recurrently Dehydrated Rats

    PubMed Central

    García-Arroyo, Fernando E.; Tapia, Edilia; Blas-Marron, Mónica G; Gonzaga, Guillermo; Silverio, Octaviano; Cristóbal, Magdalena; Osorio, Horacio; Arellano-Buendía, Abraham S.; Zazueta, Cecilia; Aparicio-Trejo, Omar Emiliano; Reyes-García, Juan G.; Pedraza-Chaverri, José; Soto, Virgilia; Roncal-Jiménez, Carlos; Johnson, Richard J.; Sánchez-Lozada, Laura G

    2017-01-01

    Recurrent dehydration and heat stress cause chronic kidney damage in experimental animals. The injury is exacerbated by rehydration with fructose-containing beverages. Fructose may amplify dehydration-induced injury by directly stimulating vasopressin release and also by acting as a substrate for the aldose reductase-fructokinase pathway, as both of these systems are active during dehydration. The role of vasopressin in heat stress associated injury has not to date been explored. Here we show that the amplification of renal damage mediated by fructose in thermal dehydration is mediated by vasopressin. Fructose rehydration markedly enhanced vasopressin (copeptin) levels and activation of the aldose reductase-fructokinase pathway in the kidney. Moreover, the amplification of the renal functional changes (decreased creatinine clearance and tubular injury with systemic inflammation, renal oxidative stress, and mitochondrial dysfunction) were prevented by the blockade of V1a and V2 vasopressin receptors with conivaptan. On the other hand, there are also other operative mechanisms when water is used as rehydration fluid that produce milder renal damage that is not fully corrected by vasopressin blockade. Therefore, we clearly showed evidence of the cross-talk between fructose, even at small doses, and vasopressin that interact to amplify the renal damage induced by dehydration. These data may be relevant for heat stress nephropathy as well as for other renal pathologies due to the current generalized consumption of fructose and deficient hydration habits.

  8. On the mechanism of renal potassium wasting in renal tubular acidosis associated with the Fanconi syndrome (type 2 RTA)

    PubMed Central

    Sebastian, Anthony; McSherry, Elisabeth; Morris, R. Curtis

    1971-01-01

    The mechanism of renal potassium wasting in renal tubular acidosis associated with the Fanconi syndrome (type 2 RTA) was investigated in 10 patients, each of whom had impaired proximal renal tubular reabsorption of bicarbonate as judged from a greater than 15-20% reduction of renal tubular bicarbonate reabsorption (THCO3-) at normal plasma bicarbonate concentrations. When the plasma bicarbonate concentration ([HCO3-]p) was experimentally increased to normal levels in three patients with a fractional potassium excretion (CK/Cin) of less than 1.0 during acidosis, CK/Cin and urinary potassium excretion (UKV/Cin) increased strikingly and concurrently with a striking increase in urinary sodium (UNaV/Cin) and bicarbonate (UHCO3-V/Cin) excretion. When [HCO3-]p was increased to normal levels in two patients with a CK/Cin of greater than 1.0 during acidosis and in whom UNaV/Cin and UHCO3-V/Cin were already markedly increased, CK/Cin did not increase further. When [HCO3-]p was decreased to subnormal levels in a patient given ammonium chloride, UKV/Cin, CK/Cin, and UHCO3-V/Cin decreased concurrently. In the six patients in whom [HCO3-]p was maintained at normal levels (oral alkali therapy) for 2 months or longer, CK/Cin was directly related to the urinary excretion rates of sodium and bicarbonate, hence was directly related to the magnitude of reduction of THCO3- at normal [HCO3-]p; CK/Cin was greater than 0.55 in all six patients and greater than 1.0 in four. In eight patients with classic RTA (type 1 RTA), proximal renal tubular reabsorption of bicarbonate was largely intact as judged from a trivial reduction of THCO3- at normal [HCO3-]p. When [HCO3-]p was either increased from subnormal to normal levels, or decreased from normal to subnormal levels, UHCO3-V/Cin remained essentially constant, and UKV/Cin did not change significantly. When correction of acidosis was sustained, UHCO3-V/Cin remained a trivial fraction of that filtered, and CK/Cin was consistently less than 0

  9. Cubilin is an albumin binding protein important for renal tubular albumin reabsorption.

    PubMed

    Birn, H; Fyfe, J C; Jacobsen, C; Mounier, F; Verroust, P J; Orskov, H; Willnow, T E; Moestrup, S K; Christensen, E I

    2000-05-01

    Using affinity chromatography and surface plasmon resonance analysis, we have identified cubilin, a 460-kDa receptor heavily expressed in kidney proximal tubule epithelial cells, as an albumin binding protein. Dogs with a functional defect in cubilin excrete large amounts of albumin in combination with virtually abolished proximal tubule reabsorption, showing the critical role for cubilin in the uptake of albumin by the proximal tubule. Also, by immunoblotting and immunocytochemistry we show that previously identified low-molecular-weight renal albumin binding proteins are fragments of cubilin. In addition, we find that mice lacking the endocytic receptor megalin show altered urinary excretion, and reduced tubular reabsorption, of albumin. Because cubilin has been shown to colocalize and interact with megalin, we propose a mechanism of albumin reabsorption mediated by both of these proteins. This process may prove important for understanding interstitial renal inflammation and fibrosis caused by proximal tubule uptake of an increased load of filtered albumin.

  10. Homozygosity mapping of the locus responsible for renal tubular dysplasia of cattle on bovine chromosome 1.

    PubMed

    Ohba, Y; Kitagawa, H; Kitoh, K; Asahina, S; Nishimori, K; Yoneda, K; Kunieda, T; Sasaki, Y

    2000-04-01

    Renal tubular dysplasia is a hereditary disease of Japanese black cattle showing renal failure and growth retardation with an autosomal recessive trait. In the present study, we mapped the locus responsible for the disease (RTD) by linkage analysis with an inbred paternal half-sib pedigree obtained from commercial herds. By analyzing segregation of microsatellite markers in the half-sibs, significant linkage was observed between the RTD locus and markers on bovine Chromosome (Chr) 1 with the highest lod score of 11.4. Homozygosity mapping with the inbred pedigree further defined the localization of the RTD locus in a 4-cM region between microsatellite markers BMS4003 and INRA119. Mapping of the RTD locus on bovine Chr 1 will facilitate cloning and characterization of the gene responsible for this disease.

  11. Arthrogryposis-renal tubular dysfunction-cholestasis syndrome: a cause of neonatal cholestasis. Case report.

    PubMed

    Ilhan, Ozkan; Ozer, Esra A; Ozdemir, Senem A; Akbay, Sinem; Memur, Seyma; Kanar, Berat; Tatli, Mustafa M

    2016-02-01

    Arthrogryposis-renal dysfunction-cholestasis syndrome is a rare lethal disorder that involves multipl organ system. It is inherited autosomal recessive and caused by defects in the VPS33B and VIPAR genes. Three cardinal findings of this syndrome are arthrogryposis, renal tubular dysfunction and cholestasis.The other organ involvements including ichthyosis, central nervous system malformation, platelet anomalies, congenital heart defects and severe failure to thrive are sometimes associated with this syndrome. Clinical findings, organ biopsy and mutational analysis can help for diagnosing but there is no curative treatment except supportive care. Several symptoms of this condition are already usually present in the neonatal period: arthrogryposis, neonatal cholestasis, skin lesions, among others. Usually survival is until the first year of life. We present a newborn whose evolution was rapidly fatal.

  12. Uric Acid Induces Renal Inflammation via Activating Tubular NF-κB Signaling Pathway

    PubMed Central

    Zhou, Yang; Fang, Li; Jiang, Lei; Wen, Ping; Cao, Hongdi; He, Weichun; Dai, Chunsun; Yang, Junwei

    2012-01-01

    Inflammation is a pathologic feature of hyperuricemia in clinical settings. However, the underlying mechanism remains unknown. Here, infiltration of T cells and macrophages were significantly increased in hyperuricemia mice kidneys. This infiltration of inflammatory cells was accompanied by an up-regulation of TNF-α, MCP-1 and RANTES expression. Further, infiltration was largely located in tubular interstitial spaces, suggesting a role for tubular cells in hyperuricemia-induced inflammation. In cultured tubular epithelial cells (NRK-52E), uric acid, probably transported via urate transporter, induced TNF-α, MCP-1 and RANTES mRNA as well as RANTES protein expression. Culture media of NRK-52E cells incubated with uric acid showed a chemo-attractive ability to recruit macrophage. Moreover uric acid activated NF-κB signaling. The uric acid-induced up-regulation of RANTES was blocked by SN 50, a specific NF-κB inhibitor. Activation of NF-κB signaling was also observed in tubule of hyperuricemia mice. These results suggest that uric acid induces renal inflammation via activation of NF-κB signaling. PMID:22761883

  13. Differential uptake of Tc-99m DMSA and Tc-99m EC in renal tubular disorders: Report of two cases and review of the literature

    PubMed Central

    Reddy Gorla, Arun Kumar; Agrawal, Kanhaiyalal; Sood, Ashwani; Bhattacharya, Anish; Mittal, Bhagwant Rai

    2014-01-01

    Tc-99m DMSA and Tc-99m EC studies are invaluable functional imaging modalities for renal structural and functional assessment. Normally, the relative renal function estimated by the two methods correlates well with each other. We here present two patients with renal tubular acidosis who showed impaired/altered DMSA uptake with normal EC renal dynamic study depicting the pitfall of DMSA imaging in tubular disorders. The two presented cases also depict distinct pattern of Tc-99m DMSA scintigraphic findings in patients with proximal and distal renal tubular acidosis, thus highlighting the factors affecting DMSA kinetics. PMID:25210282

  14. Differential uptake of Tc-99m DMSA and Tc-99m EC in renal tubular disorders: Report of two cases and review of the literature.

    PubMed

    Reddy Gorla, Arun Kumar; Agrawal, Kanhaiyalal; Sood, Ashwani; Bhattacharya, Anish; Mittal, Bhagwant Rai

    2014-07-01

    Tc-99m DMSA and Tc-99m EC studies are invaluable functional imaging modalities for renal structural and functional assessment. Normally, the relative renal function estimated by the two methods correlates well with each other. We here present two patients with renal tubular acidosis who showed impaired/altered DMSA uptake with normal EC renal dynamic study depicting the pitfall of DMSA imaging in tubular disorders. The two presented cases also depict distinct pattern of Tc-99m DMSA scintigraphic findings in patients with proximal and distal renal tubular acidosis, thus highlighting the factors affecting DMSA kinetics.

  15. Hyperkalemic distal renal tubular acidosis caused by immunosuppressant treatment with tacrolimus in a liver transplant patient: case report.

    PubMed

    Riveiro-Barciela, M; Campos-Varela, I; Tovar, J L; Vargas, V; Simón-Talero, M; Ventura-Cots, M; Crespo, M; Bilbao, I; Castells, L

    2011-12-01

    Nephrotoxicity is one of the most common side effects of long-term immunosuppressive therapy with calcineurin inhibitors. We describe a case of distal renal tubular acidosis secondary to tacrolimus administration. A 43-year-old man with end-stage liver disease due to hepatitis C and B virus infections and alcoholic cirrhosis received a liver transplantation under immunosuppressive treatment with tacrolimus and mycophenolate mofetil. In the postoperative period, the patient developed hyperkalemic hyperchloremic metabolic acidosis, with a normal serum anion gap and a positive urinary anion gap, suggesting distal renal tubular acidosis. We excluded other causes of hyperkalemia. Administration of intravenous bicarbonate, loop diuretics, and oral resin exchanger corrected the acidosis and potassium levels. Distal renal tubular acidosis is one of several types of nephrotoxicity induced by tacrolimus treatment, resulting from inhibition of potassium secretion in the collecting duct. Treatment to correct the acidosis and hyperkalemia should be promptly initiated, and the tacrolimus dose adjusted when possible.

  16. Genotype-phenotype correlations in normotensive patients with primary renal tubular hypokalemic metabolic alkalosis.

    PubMed

    Bettinelli, A; Vezzoli, G; Colussi, G; Bianchetti, M G; Sereni, F; Casari, G

    1998-01-01

    Among the different forms of hereditary renal tubulopathies associated with hypokalemia, metabolic alkalosis and normotension, two main types of disorders have been identified: Gitelman disease, which appears to be a homogeneous post-Henle's loop disorder, and Bartter syndrome, a heterogeneous Henle loop disorder. A specific gene has been found responsible for Gitelman disease, encoding the thiazide-sensitive Na-Cl cotransporter (TSC) of the distal convoluted tubule. From a phenotypic point of view the characteristic findings of this disease are hypocalciuria, hypomagnesemia and tetanic crises appearing during childhood or later. Many subjects are asymptomatic. At least three different genes have been shown to be responsible for Bartter syndrome, characterized by mutations in the proteins encoding respectively the bumetanide-sensitive Na-K-2Cl cotransporter, the inwardly-rectifying renal potassium channel and a renal chloride channel, all protein transports located in the ascending limb of Henle's loop. Mutations in the first two transport proteins have been demonstrated in patients with the hypercalciuric forms of Bartter syndrome associated with nephrocalcinosis (respectively Bartter syndrome type I and II), who were often born after pregnancies complicated by polyhydramnios and premature delivery. Mutations in the gene encoding a renal chloride channel were recently recognized in patients with a Henle tubular defect not associated with nephrocalcinosis (Bartter syndrome type III). Most of the latter group of patients were normo-hypercalciuric and presented dehydration and life-threatening hypotension in the first year of life. However, these three genes do not explain all the patients with Bartter syndrome which unlike Gitelman disease, appears to be a very heterogeneous disorder. Clearance studies, especially if done during furosemide and/or hydrochlorothiazide administration, have been helpful in identifying the site of tubular involvement. Considering both

  17. CD40: a mediator of pro- and anti-inflammatory signals in renal tubular epithelial cells.

    PubMed

    Laxmanan, Sreenivas; Datta, Dipak; Geehan, Christopher; Briscoe, David M; Pal, Soumitro

    2005-09-01

    Infiltration of immune cells into the renal interstitium is characteristic of chronic inflammatory kidney diseases. CD4+ T cells and platelets express CD40 ligand (CD40L) and are reported to mediate proinflammatory events in renal proximal tubular epithelial cells (RPTEC) via interaction with CD40. In other cell types, CD40 signals can also induce protective genes. Here, human RPTEC were treated with sCD40L to ligate CD40, and a significant increase in the generation of proinflammatory reactive oxygen species was found; however, CD40-activated cells did not undergo apoptosis. This suggests that CD40 signals may simultaneously induce antiapoptotic genes for cytoprotection of RPTEC. Heme oxygenase-1 (HO-1) expressed in RPTEC serves as a protective gene, but it is not known whether it is regulated by CD40. Next, RPTEC were transiently transfected with a full-length HO-1 promoter-luciferase construct and were treated with sCD40L. CD40 ligation was found to significantly increase HO-1 promoter activity. By electrophoretic mobility shift assay, it was confirmed that CD40 signaling induced the transcriptional activation of HO-1 through the binding of NF-kappaB to its promoter. By Western blot analysis, a marked increase in HO-1 protein expression following CD40 ligation was also found. These observations are of clinical significance because it was found that CD40 and HO-1 are induced in expression in vivo in inflamed rejecting kidney biopsies and co-expressed in renal tubules. Therefore, ligation of CD40 in RPTEC promotes both inflammatory and anti-inflammatory processes. Regulating the balance between these two events may be of importance in the prevention of tubular injury associated with renal disease.

  18. Luminal and basolateral mechanisms involved in the renal tubular uptake of inorganic mercury

    SciTech Connect

    Zalups, R.K.; Minor, K.H.

    1995-09-01

    The present study provides evidence for the existence of both a luminal and a basolateral mechanism involved in the renal tubular uptake of inorganic mercury. The researchers compared the disposition of inorganic mercury in groups of surgical control rats, rats that underwent a unilateral ureteral ligation, and rats that underwent a bilateral ureteral ligation that were pretreated with either normal saline or a 7.5 mmol/kg intravenous dose of PAH 5 min prior to receiving a nontoxic 0.5-{mu}mol/kg intravenous dose of mercuric chloride. The {open_quotes}stop-flow{close_quotes} conditions induced by either unilateral or bilateral ureteral ligation caused a significant reduction in the uptake and content of mercury in the kidneys (whose ureter was ligated) both at 1 h and 24 h after the intravenous injection of the nontoxic dose of mercuric chloride. This decreased renal uptake of mercury was due specifically to decreased uptake of mercury in the renal cortex and outer stripe of the outer medulla. The amount of mercury has not taken up during ureteral ligation represents the portion of mercury that is presumably taken up by a luminal mechanism. Pretreatment with PAH also caused a significant reduction in the renal uptake of mercury in the cortex and outer stripe of the outer medulla. When either unilateral or bilateral ureteral ligation was combined with PAH pretreatment, an additive inhibitory effect occurred with respect to the renal uptake of mercury. In fact, the renal uptake of mercury was reduced by approximately 85% at 1 h after the injection of mercuric chloride. Since the luminal uptake of mercury was blocked by ureteral ligation, the effect of PAH on the renal uptake of mercury must have occurred at the basolateral membrane. Two distinct mechanisms are involved in mercury uptake, with one mechanism located on the luminal membrane and another located on the basolateral membrane. 22 refs., 11 figs., 2 tabs.

  19. Gastrin stimulates renal dopamine production by increasing the renal tubular uptake of l-DOPA.

    PubMed

    Jiang, Xiaoliang; Zhang, Yanrong; Yang, Yu; Yang, Jian; Asico, Laureano D; Chen, Wei; Felder, Robin A; Armando, Ines; Jose, Pedro A; Yang, Zhiwei

    2017-01-01

    Gastrin is a peptide hormone that is involved in the regulation of sodium balance and blood pressure. Dopamine, which is also involved in the regulation of sodium balance and blood pressure, directly or indirectly interacts with other blood pressure-regulating hormones, including gastrin. This study aimed to determine the mechanisms of the interaction between gastrin and dopamine and tested the hypothesis that gastrin produced in the kidney increases renal dopamine production to keep blood pressure within the normal range. We show that in human and mouse renal proximal tubule cells (hRPTCs and mRPTCs, respectively), gastrin stimulates renal dopamine production by increasing the cellular uptake of l-DOPA via the l-type amino acid transporter (LAT) at the plasma membrane. The uptake of l-DOPA in RPTCs from C57Bl/6J mice is lower than in RPTCs from normotensive humans. l-DOPA uptake in renal cortical slices is also lower in salt-sensitive C57Bl/6J than in salt-resistant BALB/c mice. The deficient renal cortical uptake of l-DOPA in C57Bl/6J mice may be due to decreased LAT-1 activity that is related to its decreased expression at the plasma membrane, relative to BALB/c mice. We also show that renal-selective silencing of Gast by the renal subcapsular injection of Gast siRNA in BALB/c mice decreases renal dopamine production and increases blood pressure. These results highlight the importance of renal gastrin in stimulating renal dopamine production, which may give a new perspective in the prevention and treatment of hypertension. Copyright © 2017 the American Physiological Society.

  20. Stereoselective renal tubular secretion of levocetirizine and dextrocetirizine, the two enantiomers of the H1-antihistamine cetirizine.

    PubMed

    Strolin Benedetti, M; Whomsley, R; Mathy, F-X; Jacques, P; Espie, P; Canning, M

    2008-02-01

    Competition for uptake and/or efflux transporters can be responsible for drug interactions. Cetirizine is mainly eliminated unchanged in urine through both glomerular filtration and tubular secretion. The aim of this study was to investigate whether the eutomer, levocetirizine, and the distomer, dextrocetirizine, have a similar tubular secretion. The renal clearance associated with tubular secretion was calculated from the renal clearance of levocetirizine and dextrocetirizine obtained in a study in healthy volunteers. The values of the unbound fraction in plasma were obtained in an in vitro study of the binding of (14)C-cetirizine and (14)C-levocetirizine to human plasma proteins using equilibrium dialysis and chiral high-performance liquid chromatography (HPLC) with on-line liquid scintillation counting. The unbound fraction was 0.074 for levocetirizine and 0.141 for dextrocetirizine. The tubular secretion of dextrocetirizine (44.5 mL/min) is higher than that of levocetirizine (23.1 mL/min), which may have consequences for drug interactions at the renal level. The higher tubular secretion for dextrocetirizine may be due to the higher free fraction available for secretion or to a higher affinity for (a) renal transporter(s) mediating the secretion pathway.

  1. The effect of maleate induced proximal tubular dysfunction on the renal handling of Tc-99m DMSA in the rat

    SciTech Connect

    Provoost, A.P.; Van Aken, M.

    1984-01-01

    In the healthy kidney Tc-99m DMSA accumulates in the proximal tubular cells. Consequently, impairment of the reabsorptive function of these cells may alter the renal handling of this static renal imaging agent. The authors investigated in rats the effects of a sodiummaleate (Ma) (2mmol/kg iv) induced proximal tubular dysfunction on the renal accumulation and excretion of Tc-99m DMSA. Such a treatment results in a moderate fall of the glomerular filtration rate, glycosuria, aminoaciduria and a tubular proteinuria. In 7 adult male Wistar rats, Tc-99m DMSA scans were taken before Ma, on the day of treatment, and 1 week thereafter. The accumulation of Tc-99m DMSA in kidneys (Ki) and bladder (Bl) was determined at 1, 2, 4, and 24 hours after i.v. injection. The results, expressed as a percentage of the injected dose, are presented. The findings show that a reversible Ma induced impairment of the proximal reabsorptive capacity severely alters the renal tubular handling of Tc-99m DMSA. In contrast to the control situation, only a small fraction of the DMSA is retained in the kidney and the majority is transported directly to the urinary bladder. When similar alterations are observed in clinical Tc-99m DMSA scans, this may be an indication of an impairment of the proximal tubular function.

  2. Renal tubular epithelial vacuoles-a marker for both hyperlipidemia and ketoacidosis at autopsy.

    PubMed

    Zhou, Chong; Moore, Lynette; Yool, Andrea; Jaunzems, Alvis; Byard, Roger W

    2015-05-01

    Review of 15 cases of nephrotic syndrome found that eight had significant hyperlipidemia with serum cholesterol levels ranging between 10.59 and 18.60 mmol/L (mean 12.88) and serum triglyceride levels between 2.30 and 9.92 mmol/L (mean 4.58); all of these cases displayed basal lipid vacuolization. Seven of the 15 study cases had normal-mild hyperlipidemia with serum cholesterol levels ranging between 4.71 and 7.54 mmol/L (mean 6.02) and serum triglyceride levels between 0.65 and 4.1 mmol/L (mean 1.57). Six of the seven cases had basal lipid vacuoles (86%). Of these, five cases were hyperlipidemic and one case had borderline hyperlipidemia with a serum cholesterol level of 4.71 mmol/L. Although hyperlipidemia was associated with renal tubular epithelial vacuolization, the vacuoles appeared morphologically different to those found in ketoacidosis. This study has shown that while hyperlipidemia in isolation may result in basal lipid vacuolization within renal tubular epithelial cells, the phenotype differs from that observed in ketoacidosis. © 2015 American Academy of Forensic Sciences.

  3. IL-6 augments angiotensinogen in primary cultured renal proximal tubular cells.

    PubMed

    Satou, Ryousuke; Gonzalez-Villalobos, Romer A; Miyata, Kayoko; Ohashi, Naro; Urushihara, Maki; Acres, Omar W; Navar, L Gabriel; Kobori, Hiroyuki

    2009-11-13

    In human kidneys, the mechanisms underlying angiotensinogen (AGT) augmentation by interleukin 6 (IL-6) are poorly understood and the only information available is in HK-2, immortalized human renal proximal tubular epithelial cells. Therefore, the present study was performed to elucidate the effects of IL-6 on AGT expression in primary cultured human renal proximal tubular epithelial cells (RPTEC) after characterization of HK-2 and RPTEC. RPTEC showed low basal AGT mRNA (11+/-1%) and protein (7.0+/-0.9%) expression, high IL-6 receptor (IL-6R) expression (282+/-17%), and low basal NF-kappaB (43+/-7%) and STAT3 (43+/-7%) activities compared to those in HK-2. In RPTEC, AGT mRNA and protein expressions were enhanced by IL-6 (172+/-31% and 378+/-39%, respectively). This AGT augmentation was attenuated by an IL-6R antibody. STAT3 phosphorylation (366+/-55% at 30min) and translocation were enhanced by IL-6. The AGT augmentation was attenuated by a STAT3 inhibitor. These data indicate that IL-6 increases AGT expression via STAT3 pathway in RPTEC.

  4. Engineered extracellular matrices with controlled mechanics modulate renal proximal tubular cell epithelialization

    PubMed Central

    Chen, Evan; Putnam, Andrew J.

    2017-01-01

    Acute kidney injury (AKI) is common and associated with significant morbidity and mortality. Recovery from many forms of AKI involves the proliferation of renal proximal tubular epithelial cells (RPTECs), but the influence of the microenvironment in which this recovery occurs remains poorly understood. Here we report the development of a poly(ethylene glycol) (PEG) hydrogel platform to study the influence of substrate mechanical properties on the proliferation of human RPTECs as a model for recovery from AKI. PEG diacrylate based hydrogels were generated with orthogonal control of mechanics and cell-substrate interactions. Using this platform, we found that increased substrate stiffness promotes RPTEC spreading and proliferation. RPTECs showed similar degrees of apoptosis and Yes-associated protein (YAP) nuclear localization regardless of stiffness, suggesting these were not key mediators of the effect. However, focal adhesion formation, cytoskeletal organization, focal adhesion kinase (FAK) activation, and extracellular signal-regulated kinase (ERK) activation were all enhanced with increasing substrate stiffness. Inhibition of ERK activation substantially attenuated the effect of stiffness on proliferation. In long-term culture, hydrogel stiffness promoted the formation of more complete epithelial monolayers with tight junctions, cell polarity, and an organized basement membrane. These data suggest that increased stiffness potentially may have beneficial consequences for the renal tubular epithelium during recovery from AKI. PMID:28715434

  5. Engineered extracellular matrices with controlled mechanics modulate renal proximal tubular cell epithelialization.

    PubMed

    Beamish, Jeffrey A; Chen, Evan; Putnam, Andrew J

    2017-01-01

    Acute kidney injury (AKI) is common and associated with significant morbidity and mortality. Recovery from many forms of AKI involves the proliferation of renal proximal tubular epithelial cells (RPTECs), but the influence of the microenvironment in which this recovery occurs remains poorly understood. Here we report the development of a poly(ethylene glycol) (PEG) hydrogel platform to study the influence of substrate mechanical properties on the proliferation of human RPTECs as a model for recovery from AKI. PEG diacrylate based hydrogels were generated with orthogonal control of mechanics and cell-substrate interactions. Using this platform, we found that increased substrate stiffness promotes RPTEC spreading and proliferation. RPTECs showed similar degrees of apoptosis and Yes-associated protein (YAP) nuclear localization regardless of stiffness, suggesting these were not key mediators of the effect. However, focal adhesion formation, cytoskeletal organization, focal adhesion kinase (FAK) activation, and extracellular signal-regulated kinase (ERK) activation were all enhanced with increasing substrate stiffness. Inhibition of ERK activation substantially attenuated the effect of stiffness on proliferation. In long-term culture, hydrogel stiffness promoted the formation of more complete epithelial monolayers with tight junctions, cell polarity, and an organized basement membrane. These data suggest that increased stiffness potentially may have beneficial consequences for the renal tubular epithelium during recovery from AKI.

  6. IL-6 Augments Angiotensinogen in Primary Cultured Renal Proximal Tubular Cells

    PubMed Central

    Satou, Ryousuke; Gonzalez-Villalobos, Romer A.; Miyata, Kayoko; Ohashi, Naro; Urushihara, Maki; Acres, Omar W.; Navar, L. Gabriel; Kobori, Hiroyuki

    2009-01-01

    In human kidneys, the mechanisms underlying angiotensinogen (AGT) augmentation by interleukin 6 (IL-6) are poorly understood and the only information available is in HK-2, immortalized human renal proximal tubular epithelial cells. Therefore, the present study was performed to elucidate the effects of IL-6 on AGT expression in primary cultured human renal proximal tubular epithelial cells (RPTEC) after characterization of HK-2 and RPTEC. RPTEC showed low basal AGT mRNA (11±1%) and protein (7.0±0.9%) expression, high IL-6 receptor (IL-6R) expression (282±17%), and low basal NF-κB (43±7%) and STAT3 (43±7%) activities compared to those in HK-2. In RPTEC, AGT mRNA and protein expressions were enhanced by IL-6 (172±31% and 378±39%, respectively). This AGT augmentation was attenuated by an IL-6R antibody. STAT3 phosphorylation (366±55% at 30 min) and translocation were enhanced by IL-6. The AGT augmentation was attenuated by a STAT3 inhibitor. These data indicate that IL-6 increases AGT expression via STAT3 pathway in RPTEC. PMID:19583994

  7. Sjögren syndrome presenting with hypopotassemic periodic paralysis due to renal tubular acidosis.

    PubMed

    Ataoglu, Esra Hayriye; Demir, Betul; Tuna, Mazhar; Cavus, Bilger; Cetin, Faik; Temiz, Levent Umit; Ozturk, Savas; Yenigun, Mustafa

    2012-01-01

    Sjögren syndrome (SS) is an autoimmune-lymphoproliferative disorder characterized by mononuclear cell infiltration of exocrine glands. Clinically, Sjögren syndrome (SS) has a wide spectrum, varying from autoimmune exocrinopathy to systemic involvement. There have been few cases reporting that primary SS developed with distal renal tubular acidosis clinically. Here, we present a case with primary Sjögren syndrome accompanied by hypopotassemic paralysis due to renal tubular acidosis. Severe hypopotassemia, hyperchloremic metabolic acidosis, alkaline urine and disorder in urinary acidification test were observed in the biochemical examination of the 16-year-old female patient, who had applied to our clinic for extreme loss of muscle force. After the examinations it was determined that the patient had developed Type 1 RTA (distal RTA) due to primary Sjögren syndrome. Potassium and alkaline replacement was made and an immediate total recovery was achieved. Hypopotassemic paralysis due to primary Sjögren syndrome is a rare but severe disorder that could lead to death if not detected early and cured appropriately. Thus, effective treatment should be immediately initiated in cases where severe hypopotassemia is accompanied by metabolic acidosis, and the cases should also be examined for extraglandular involvement of SS.

  8. Chronic glucose infusion causes sustained increases in tubular sodium reabsorption and renal blood flow in dogs

    PubMed Central

    Brands, Michael W.; Bell, Tracy D.; Rodriquez, Nancy A.; Polavarapu, Praveen; Panteleyev, Dmitriy

    2009-01-01

    This study tested the hypothesis that inducing hyperinsulinemia and hyperglycemia in dogs, by infusing glucose chronically intravenously, would increase tubular sodium reabsorption and cause hypertension. Glucose was infused for 6 days (14 mg·kg−1·min−1 iv) in five uninephrectomized (UNX) dogs. Mean arterial pressure (MAP) and renal blood flow (RBF) were measured 18 h/day using DSI pressure units and Transonic flow probes, respectively. Urinary sodium excretion (UNaV) decreased significantly on day 1 and remained decreased over the 6 days, coupled with a significant, sustained increase in RBF, averaging ∼20% above control on day 6. Glomerular filtration rate and plasma renin activity (PRA) also increased. However, although MAP tended to increase, this was not statistically significant. Therefore, the glucose infusion was repeated in six dogs with 70% surgical reduction in kidney mass (RKM) and high salt intake. Blood glucose and plasma insulin increased similar to the UNX dogs, and there was significant sodium retention, but MAP still did not increase. Interestingly, the increases in PRA and RBF were prevented in the RKM dogs. The decrease in UNaV, increased RBF, and slightly elevated MAP show that glucose infusion in dogs caused a sustained increase in tubular sodium reabsorption by a mechanism independent of pressure natriuresis. The accompanying increase in PRA, together with the failure of either RBF or PRA to increase in the RKM dogs, suggests the site of tubular reabsorption was before the macula densa. However, the volume retention and peripheral edema suggest that systemic vasodilation offsets any potential renal actions to increase MAP in this experimental model in dogs. PMID:19073906

  9. Chronic glucose infusion causes sustained increases in tubular sodium reabsorption and renal blood flow in dogs.

    PubMed

    Brands, Michael W; Bell, Tracy D; Rodriquez, Nancy A; Polavarapu, Praveen; Panteleyev, Dmitriy

    2009-02-01

    This study tested the hypothesis that inducing hyperinsulinemia and hyperglycemia in dogs, by infusing glucose chronically intravenously, would increase tubular sodium reabsorption and cause hypertension. Glucose was infused for 6 days (14 mg.kg(-1).min(-1) iv) in five uninephrectomized (UNX) dogs. Mean arterial pressure (MAP) and renal blood flow (RBF) were measured 18 h/day using DSI pressure units and Transonic flow probes, respectively. Urinary sodium excretion (UNaV) decreased significantly on day 1 and remained decreased over the 6 days, coupled with a significant, sustained increase in RBF, averaging approximately 20% above control on day 6. Glomerular filtration rate and plasma renin activity (PRA) also increased. However, although MAP tended to increase, this was not statistically significant. Therefore, the glucose infusion was repeated in six dogs with 70% surgical reduction in kidney mass (RKM) and high salt intake. Blood glucose and plasma insulin increased similar to the UNX dogs, and there was significant sodium retention, but MAP still did not increase. Interestingly, the increases in PRA and RBF were prevented in the RKM dogs. The decrease in UNaV, increased RBF, and slightly elevated MAP show that glucose infusion in dogs caused a sustained increase in tubular sodium reabsorption by a mechanism independent of pressure natriuresis. The accompanying increase in PRA, together with the failure of either RBF or PRA to increase in the RKM dogs, suggests the site of tubular reabsorption was before the macula densa. However, the volume retention and peripheral edema suggest that systemic vasodilation offsets any potential renal actions to increase MAP in this experimental model in dogs.

  10. Autosomal dominant osteopetrosis associated with renal tubular acidosis is due to a CLCN7 mutation.

    PubMed

    Piret, Sian E; Gorvin, Caroline M; Trinh, Anne; Taylor, John; Lise, Stefano; Taylor, Jenny C; Ebeling, Peter R; Thakker, Rajesh V

    2016-11-01

    The aim of this study was to identify the causative mutation in a family with an unusual presentation of autosomal dominant osteopetrosis (OPT), proximal renal tubular acidosis (RTA), renal stones, epilepsy, and blindness, a combination of features not previously reported. We undertook exome sequencing of one affected and one unaffected family member, followed by targeted analysis of known candidate genes to identify the causative mutation. This identified a missense mutation (c.643G>A; p.Gly215Arg) in the gene encoding the chloride/proton antiporter 7 (gene CLCN7, protein CLC-7), which was confirmed by amplification refractory mutation system (ARMS)-PCR, and to be present in the three available patients. CLC-7 mutations are known to cause autosomal dominant OPT type 2, also called Albers-Schonberg disease, which is characterized by osteosclerosis, predominantly of the spine, pelvis and skull base, resulting in bone fragility and fractures. Albers-Schonberg disease is not reported to be associated with RTA, but autosomal recessive OPT type 3 (OPTB3) with RTA is associated with carbonic anhydrase type 2 (CA2) mutations. No mutations were detected in CA2 or any other genes known to cause proximal RTA. Neither CLCN7 nor CA2 mutations have previously been reported to be associated with renal stones or epilepsy. Thus, we identified a CLCN7 mutation in a family with autosomal dominant osteopetrosis, RTA, renal stones, epilepsy, and blindness. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Thalidomide Ameliorates Inflammation and Vascular Injury but Aggravates Tubular Damage in the Irradiated Mouse Kidney

    SciTech Connect

    Scharpfenecker, Marion; Floot, Ben; Russell, Nicola S.; Coppes, Rob P.; Stewart, Fiona A.

    2014-07-01

    Purpose: The late side effects of kidney irradiation include vascular damage and fibrosis, which are promoted by an irradiation-induced inflammatory response. We therefore treated kidney-irradiated mice with the anti-inflammatory and angiogenesis-modulating drug thalidomide in an attempt to prevent the development of late normal tissue damage and radiation nephropathy in the mouse kidney. Methods and Materials: Kidneys of C57Bl/6 mice were irradiated with a single dose of 14 Gy. Starting from week 16 after irradiation, the mice were fed with thalidomide-containing chow (100 mg/kg body weight/day). Gene expression and kidney histology were analyzed at 40 weeks and blood samples at 10, 20, 30, and 40 weeks after irradiation. Results: Thalidomide improved the vascular structure and vessel perfusion after irradiation, associated with a normalization of pericyte coverage. The drug also reduced infiltration of inflammatory cells but could not suppress the development of fibrosis. Irradiation-induced changes in hematocrit and blood urea nitrogen levels were not rescued by thalidomide. Moreover, thalidomide worsened tubular damage after irradiation and also negatively affected basal tubular function. Conclusions: Thalidomide improved the inflammatory and vascular side effects of kidney irradiation but could not reverse tubular toxicity, which probably prevented preservation of kidney function.

  12. Entry of aminoglycosides into renal tubular epithelial cells via endocytosis-dependent and endocytosis-independent pathways.

    PubMed

    Nagai, Junya; Takano, Mikihisa

    2014-08-15

    Aminoglycoside antibiotics such as gentamicin and amikacin are well recognized as a clinically important antibiotic class because of their reliable efficacy and low cost. However, the clinical use of aminoglycosides is limited by their nephrotoxicity and ototoxicity. Nephrotoxicity is induced mainly due to high accumulation of the antibiotics in renal proximal tubular cells. Therefore, a lot of studies on characterization of the renal transport system for aminoglycosides so far reported involved various in-vivo and in-vitro techniques. Early studies revealed that aminoglycosides are taken up through adsorptive endocytosis in renal epithelial cells. Subsequently, it was found that megalin, a multiligand endocytic receptor abundantly expressed on the apical side of renal proximal tubular cells, can bind aminoglycosides and that megalin-mediated endocytosis plays a crucial role in renal accumulation of aminoglycosides. Therefore, megalin has been suggested to be a promising molecular target for the prevention of aminoglycoside-induced nephrotoxicity. On the other hand, recently, some reports have indicated that aminoglycosides are transported via a pathway that does not require endocytosis, such as non-selective cation channel-mediated entry, in cultured renal tubular cells as well as cochlear outer hair cells. In this commentary article, we review the cellular transport of aminoglycosides in renal epithelial cells, focusing on endocytosis-dependent and -independent pathways.

  13. Glutamate dehydrogenase requirement for apoptosis induced by aristolochic acid in renal tubular epithelial cells.

    PubMed

    Romanov, Victor; Whyard, Terry; Bonala, Radha; Johnson, Francis; Grollman, Arthur

    2011-12-01

    Ingestion of aristolochic acids (AA) contained in herbal remedies results in a renal disease and, frequently, urothelial malignancy. The genotoxicity of AA in renal cells, including mutagenic DNA adduct formation, is well-documented. However, the mechanisms of AA-induced tubular atrophy and renal fibrosis are largely unknown. Epithelial cell death is a critical characteristic of these pathological conditions. To elucidate the mechanisms of AA-induced cytotoxicity, we explored AA-interacting proteins in tubular epithelial cells (TEC). We found that AA interacts with a mitochondrial enzyme glutamate dehydrogenase (GDH) and moderately inhibits its activity. We report that AA induces cell death in GDH-knockdown TEC preferentially via non-apoptotic means, whereas in GDH-positive cells, death was executed by both the non-apoptotic and apoptotic mechanisms. Apoptosis is an energy-reliant process and demands higher adenosine 5'-triphosphate (ATP) consumption than does the non-apoptotic cell death. We found that, after AAI treatment, the ATP depletion is more pronounced in GDH-knockdown cells. When we reduced ATP in TEC cells by inhibition of glycolysis and mitochondrial respiration, cell death mode switched from apoptosis and necrosis to necrosis only. In addition, in cells incubated at low glucose and no glutamine conditions, oxaloacetate and pyruvate reduced AAI-induced apoptosis our data suggest that AAI-GDH interactions in TEC are critical for the induction of apoptosis by direct inhibition of GDH activity. AA binding may also induce changes in GDH conformation and promote interactions with other molecules or impair signaling by GDH metabolic products, leading to apoptosis.

  14. Zika virus infects renal proximal tubular epithelial cells with prolonged persistency and cytopathic effects.

    PubMed

    Chen, Jian; Yang, Yi-Feng; Chen, Jun; Zhou, Xiaohui; Dong, Zhaoguang; Chen, Tianyue; Yang, Yu; Zou, Peng; Jiang, Biao; Hu, Yunwen; Lu, Lu; Zhang, Xiaoyan; Liu, Jia; Xu, Jianqing; Zhu, Tongyu

    2017-08-23

    Zika virus (ZIKV) infection can cause fetal developmental abnormalities and Guillain-Barré syndrome in adults. Although progress has been made in understanding the link between ZIKV infection and microcephaly, the pathology of ZIKV, particularly the viral reservoirs in human, remains poorly understood. Several studies have shown that compared to serum samples, patients' urine samples often have a longer duration of ZIKV persistency and higher viral load. This finding suggests that an independent viral reservoir may exist in the human urinary system. Despite the clinical observations, the host cells of ZIKV in the human urinary system are poorly characterized. In this study, we demonstrate that ZIKV can infect renal proximal tubular epithelial cells (RPTEpiCs) in immunodeficient mice in vivo and in both immortalized and primary human renal proximal tubular epithelial cells (hRPTEpiCs) in vitro. Importantly, ZIKV infection in mouse kidneys caused caspase-3-mediated apoptosis of renal cells. Similarly, in vitro infection of immortalized and primary hRPTEpiCs resulted in notable cytopathic effects. Consistent with the clinical observations, we found that ZIKV infection can persist with prolonged duration in hRPTEpiCs. RNA-Seq analyses of infected hRPTEpiCs revealed a large number of transcriptional changes in response to ZIKV infection, including type I interferon signaling genes and anti-viral response genes. Our results suggest that hRPTEpiCs are a potential reservoir of ZIKV in the human urinary system, providing a possible explanation for the prolonged persistency of ZIKV in patients' urine.

  15. Renal tubular receptor imaging with iodine-131-labeled peanut lectin: pharmacokinetics and renal clearance mechanism in animals

    SciTech Connect

    Boniface, G.R.; Suresh, M.R.; Willans, D.J.; Tam, Y.K.; Shysh, A.; Longenecker, B.M.; Noujaim, A.A.

    1986-05-01

    Intravenously administered peanut lectin (PNA), iodinated with /sup 131/I ((/sup 131/I)PNA), is rapidly cleared from the plasma by the kidneys in dogs (clearance (total body) = 17.52 +/- 8.74 ml/min). Dynamic gamma camera renal scintigraphy demonstrated renal accumulation and excretion phases of the (/sup 131/I)PNA renogram in dogs and rabbits (% injection dose-at-peak = 21.8 +/- 3.3% and 19.6 +/- 4.3%, time-to-peak = 44.6 +/- 4.8 min and 37.2 +/- 6.9 min, respectively). Immunoperoxidase staining of kidney sections, following i.v. administered PNA, demonstrated predominant accumulation by the proximal tubules of mice, rabbits, and dogs. The basement membrane was intensely stained at early times p.i. while intracellular and luminal PNA was evident within 1 hr. Urine analysis confirmed the presence of intact (/sup 131/I)PNA in the bladder contents, while protein degradation products, and a small percentage of the free iodide (less than 5%) were noted within 1 hr p.i. The relative proportion of free iodide increased at later times p.i. (greater than 6 hr). A receptor mediated excretion mechanism is proposed for the clearance of PNA and may be useful for the study of renal tubular function.

  16. Medullary sponge kidney presenting in a neonate with distal renal tubular acidosis and failure to thrive: a case report

    PubMed Central

    2009-01-01

    Introduction Medullary sponge kidney is a congenital anomaly characterized by diffuse ectasy of the collecting tubules of one or both kidneys. It is usually diagnosed in the second or third decade of life. Case presentation Distal renal tubular acidosis is commonly observed in patients with medullary sponge kidney. We describe here a 50-day-old Egyptian Caucasian girl with medullary sponge kidney who had features of distal renal tubular acidosis, (persistent alkaline urine, hypercalciuria, hypocitraturia) and failure to thrive. Renal ultrasound revealed left renal increased medullary echogenicity and bilateral nephrocalcinosis. Conclusion Early gene(s) expression of medullary sponge kidney disease might be responsible for persistent metabolic acidosis during the neonatal period. PMID:19830120

  17. Hyperlipidemia-Associated Renal Damage Decreases Klotho Expression in Kidneys from ApoE Knockout Mice

    PubMed Central

    Sastre, Cristina; Rubio-Navarro, Alfonso; Buendía, Irene; Gómez-Guerrero, Carmen; Blanco, Julia; Mas, Sebastian; Egido, Jesús; Blanco-Colio, Luis Miguel; Ortiz, Alberto; Moreno, Juan Antonio

    2013-01-01

    Background Klotho is a renal protein with anti-aging properties that is downregulated in conditions related to kidney injury. Hyperlipidemia accelerates the progression of renal damage, but the mechanisms of the deleterious effects of hyperlipidemia remain unclear. Methods We evaluated whether hyperlipidemia modulates Klotho expression in kidneys from C57BL/6 and hyperlipidemic apolipoprotein E knockout (ApoE KO) mice fed with a normal chow diet (ND) or a Western-type high cholesterol-fat diet (HC) for 5 to 10 weeks, respectively. Results In ApoE KO mice, the HC diet increased serum and renal cholesterol levels, kidney injury severity, kidney macrophage infiltration and inflammatory chemokine expression. A significant reduction in Klotho mRNA and protein expression was observed in kidneys from hypercholesteromic ApoE KO mice fed a HC diet as compared with controls, both at 5 and 10 weeks. In order to study the mechanism involved in Klotho down-regulation, murine tubular epithelial cells were treated with ox-LDL. Oxidized-LDL were effectively uptaken by tubular cells and decreased both Klotho mRNA and protein expression in a time- and dose-dependent manner in these cells. Finally, NF-κB and ERK inhibitors prevented ox-LDL-induced Klotho downregulation. Conclusion Our results suggest that hyperlipidemia-associated kidney injury decreases renal expression of Klotho. Therefore, Klotho could be a key element explaining the relationship between hyperlipidemia and aging with renal disease. PMID:24386260

  18. Urinary excretion of beta 2-glycoprotein-1 (apolipoprotein H) and other markers of tubular malfunction in "non-tubular" renal disease.

    PubMed Central

    Flynn, F. V.; Lapsley, M.; Sansom, P. A.; Cohen, S. L.

    1992-01-01

    AIM: To determine whether urinary beta 2-glycoprotein-1 assays can provide improved discrimination between chronic renal diseases which are primarily of tubular or glomerular origin. METHODS: Urinary beta 2-glycoprotein-1, retinol-binding protein, alpha 1-microglobulin, beta 2-microglobulin, N-acetyl-beta-D-glucosa-minidase and albumin were measured in 51 patients with primary glomerular disease, 23 with obstructive nephropathy, and 15 with polycystic kidney disease, and expressed per mmol of creatinine. Plasma beta 2-glycoprotein-1 was assayed in 52 patients and plasma creatinine in all 89. The findings were compared between the diagnostic groups and with previously published data relating to primary tubular disorders. RESULTS: All 31 patients with plasma creatinine greater than 200 mumol/l excreted increased amounts of beta 2-glycoprotein-1, retinol-binding protein, and alpha 1-microglobulin, and 29 had increased N-acetyl-beta-D-glucosaminidase; the quantities were generally similar to those found in comparable patients with primary tubular pathology. Among 58 with plasma creatinine concentrations under 200 mumol/l, increases in beta 2-glycoprotein-1, retinol-binding protein, and alpha 1-microglobulin excretion were less common and much smaller, especially in those with obstructive nephropathy and polycystic disease. The ratios of the excretion of albumin to the other proteins provided the clearest discrimination between the patients with glomerular or tubular malfunction, but an area of overlap was present which embraced those with obstructive nephropathy and polycystic disease. CONCLUSIONS: Increased excretion of beta 2-glycoprotein-1 due to a raised plasma concentration or diminution of tubular reabsorption, or both, is common in all the forms of renal disease investigated, and both plasma creatinine and urinary albumin must be taken into account when interpreting results. Ratios of urinary albumin: beta 2-glycoprotein-1 greater than 1000 are highly suggestive

  19. DC-SIGN reacts with TLR4 and regulates inflammatory cytokine expression via NF-κB activation in renal tubular epithelial cells during acute renal injury.

    PubMed

    Feng, Danying; Wang, Yanping; Liu, Yan; Wu, Liping; Li, Xiao; Chen, Yufan; Chen, Yuanyuan; Chen, Yafeng; Xu, Chundi; Yang, Ke; Zhou, Tong

    2017-09-12

    In the pathological process of acute kidney injury (AKI), innate immune receptors are essential in inflammatory response modulation; however, the precise molecular mechanisms are still unclear. Our study sought to demonstrate the inflammatory response mechanisms in renal tubular epithelial cells via Toll-like receptor 4 (TLR4) and dendritic cell-specific ICAM-3-grabbing non-integrin 1 (DC-SIGN) signaling. We found that DC-SIGN exhibited strong expression in renal tubular epithelial cells of human acute renal injury tissues. DC-SIGN protein expression was significantly increased when renal tubular epithelial cells were exposed to lipopolysaccharide (LPS) for a short period. Furthermore, DC-SIGN was involved in the activation of p65 by TLR4, which excluded p38 and JNK. Interleukin 6 (IL-6) and tumor necrosis factor-α (TNFα) expression were decreased after DC-SIGN knockdown. Furthermore, LPS induced endogenous interactions and plasma membrane co-expression between TLR4 and DC-SIGN. These results showed that DC-SIGN and TLR4 interactions regulate inflammatory responses in renal tubular epithelial cells and participate in AKI pathogenesis. This article is protected by copyright. All rights reserved. © 2017 British Society for Immunology.

  20. The diagnostic value of the urine to blood carbon dioxide tension gradient for the assessment of distal tubular hydrogen secretion in pediatric patients with renal tubular disorders.

    PubMed

    Donckerwolcke, R A; Valk, C; van Wijngaarden-Penterman, M J; van Stekelenburg, G J

    1983-05-01

    The urine to blood carbon dioxide tension gradient (U-B PCO2) following alkalinization of the urine (pH = 7.8) has been widely used to assess distal tubular hydrogen secretion. The magnitude of the U-B PCO2 is influenced not only by the rate of hydrogen secretion but also by bicarbonate concentration and water abstraction. Simultaneous administration of sodium bicarbonate and dDAVP improve the reliability of the test in healthy children. Children with distal renal tubular acidosis were not able to increase urinary PCO2, while a normal increase was found in patients with proximal renal tubular acidosis and the Fanconi Syndrome. Four out of nine patients with urolithiasis failed to increase urinary PCO2 following NaHCO3 and dDAVP-administration, despite a normal ability to acidify the urine following NH4Cl administration. To assess the effect of acute alterations in urinary concentration on urinary PCO2, the test was carried out in children with central diabetes insipidus. Despite sharp increase in urinary bicarbonate concentration these patients failed to increase urinary PCO2.

  1. Role of mitochondrial permeability transition in human renal tubular epithelial cell death induced by aristolochic acid

    SciTech Connect

    Qi Xinming; Cai Yan; Gong Likun; Liu Linlin; Chen Fangping; Xiao Ying; Wu Xiongfei; Li Yan; Xue Xiang |; Ren Jin . E-mail: cdser_simm@mail.shcnc.ac.cn

    2007-07-01

    Aristolochic acid (AA), a natural nephrotoxin and carcinogen, can induce a progressive tubulointerstitial nephropathy. However, the mechanism by which AA causes renal injury remains largely unknown. Here we reported that the mitochondrial permeability transition (MPT) plays an important role in the renal injury induced by aristolochic acid I (AAI). We found that in the presence of Ca{sup 2+}, AAI caused mitochondrial swelling, leakage of Ca{sup 2+}, membrane depolarization, and release of cytochrome c in isolated kidney mitochondria. These alterations were suppressed by cyclosporin A (CsA), an agent known to inhibit MPT. Culture of HK-2 cell, a human renal tubular epithelial cell line for 24 h with AAI caused a decrease in cellular ATP, mitochondrial membrane depolarization, cytochrome c release, and increase of caspase 3 activity. These toxic effects of AAI were attenuated by CsA and bongkrekic acid (BA), another specific MPT inhibitor. Furthermore, AAI greatly inhibited the activity of mitochondrial adenine nucleotide translocator (ANT) in isolated mitochondria. We suggested that ANT may mediate, at least in part, the AAI-induced MPT. Taken together, these results suggested that MPT plays a critical role in the pathogenesis of HK-2 cell injury induced by AAI and implied that MPT might contribute to human nephrotoxicity of aristolochic acid.

  2. BAG3 regulates ECM accumulation in renal proximal tubular cells induced by TGF-β1.

    PubMed

    Du, Feng; Li, Si; Wang, Tian; Zhang, Hai-Yan; Li, De-Tian; Du, Zhen-Xian; Wang, Hua-Qin; Wang, Yan-Qiu

    2015-01-01

    Previously we have demonstrated that Bcl-2-associated athanogene 3 (BAG3) is increased in renal fibrosis using a rat unilateral ureteral obstruction model. The current study investigated the role of BAG3 in renal fibrosis using transforming growth factor (TGF)-β1-treated human proximal tubular epithelial (HK-2) cells. An upregulation of BAG3 in vitro models was observed, which correlated with the increased synthesis of extracellular matrix (ECM) proteins and expression of tissue-type plasminogen activator inhibitor (PAI)-1. Blockade of BAG3 induction by shorting hairpin RNA suppressed the expression of ECM proteins but had no effect on PAI-1 expression induced by TGF-β1. Forced overexpression of BAG3 selectively increased collagens. TGF-β1-induced BAG3 expression in HK-2 cells was attenuated by ERK1/2 and JNK MAPK inhibitors. In addition, forced BAG3 overexpression blocked attenuation of collagens expression by ERK1/2 and JNK inhibitors. These data suggest that ERK1/2 and JNK signaling events are involved in modulating the expression of BAG3, which would ultimately contribute to renal fibrosis by enhancing the synthesis and deposition of ECM proteins.

  3. Proximal renal tubular acidosis: a not so rare disorder of multiple etiologies

    PubMed Central

    Haque, Syed K.; Ariceta, Gema; Batlle, Daniel

    2012-01-01

    Proximal renal tubular acidosis (RTA) (Type II RTA) is characterized by a defect in the ability to reabsorb HCO3 in the proximal tubule. This is usually manifested as bicarbonate wastage in the urine reflecting that the defect in proximal tubular transport is severe enough that the capacity for bicarbonate reabsorption in the thick ascending limb of Henle's loop and more distal nephron segments is overwhelmed. More subtle defects in proximal bicarbonate transport likely go clinically unrecognized owing to compensatory reabsorption of bicarbonate distally. Inherited proximal RTA is more commonly autosomal recessive and has been associated with mutations in the basolateral sodium-bicarbonate cotransporter (NBCe1). Mutations in this transporter lead to reduced activity and/or trafficking, thus disrupting the normal bicarbonate reabsorption process of the proximal tubules. As an isolated defect for bicarbonate transport, proximal RTA is rare and is more often associated with the Fanconi syndrome characterized by urinary wastage of solutes like phosphate, uric acid, glucose, amino acids, low-molecular-weight proteins as well as bicarbonate. A vast array of rare tubular disorders may cause proximal RTA but most commonly it is induced by drugs. With the exception of carbonic anhydrase inhibitors which cause isolated proximal RTA, drug-induced proximal RTA is associated with Fanconi syndrome. Drugs that have been recently recognized to cause severe proximal RTA with Fanconi syndrome include ifosfamide, valproic acid and various antiretrovirals such as Tenofovir particularly when given to human immunodeficiency virus patients receiving concomitantly protease inhibitors such as ritonavir or reverse transcriptase inhibitors such as didanosine. PMID:23235953

  4. Activation of ERK accelerates repair of renal tubular epithelial cells, whereas it inhibits progression of fibrosis following ischemia/reperfusion injury.

    PubMed

    Jang, Hee-Seong; Han, Sang Jun; Kim, Jee In; Lee, Sanggyu; Lipschutz, Joshua H; Park, Kwon Moo

    2013-12-01

    Extracellular signal-regulated kinase (ERK) signals play important roles in cell death and survival. However, the role of ERK in the repair process after injury remains to be defined in the kidney. Here, we investigated the role of ERK in proliferation and differentiation of tubular epithelial cells, and proliferation of interstitial cells following ischemia/reperfusion (I/R) injury in the mouse kidney. Mice were subjected to 30min of renal ischemia. Some mice were administered with U0126, a specific upstream inhibitor of ERK, daily during the recovery phase, beginning at 1day after ischemia until sacrifice. I/R caused severe tubular cell damage and functional loss in the kidney. Nine days after ischemia, the kidney was restored functionally with a partial restoration of damaged tubules and expansion of fibrotic lesions. ERK was activated by I/R and the activated ERK was sustained for 9days. U0126 inhibited the proliferation, basolateral relocalization of Na,K-ATPase and lengthening of primary cilia in tubular epithelial cells, whereas it enhanced the proliferation of interstitial cells and accumulation of extracellular matrix. Furthermore, U0126 elevated the expression of cell cycle arrest-related proteins, p21 and phospholylated-chk2 in the post-ischemic kidney. U0126 mitigated the post-I/R increase of Sec10 which is a crucial component of exocyst complex and an important factor in ciliogenesis and tubulogenesis. U0126 also enhanced the expression of fibrosis-related proteins, TGF-β1 and phosphorylated NF-κB after ischemia. Our findings demonstrate that activation of ERK is required for both the restoration of damaged tubular epithelial cells and the inhibition of fibrosis progression following injury. © 2013.

  5. Bikunin prevents adhesion of calcium oxalate crystal to renal tubular cells in human urine.

    PubMed

    Ebisuno, S; Nishihata, M; Inagaki, T; Umehara, M; Kohjimoto, Y

    1999-11-01

    Crystal-renal tubular cell interactions are important factors in crystal retention and development of kidney stones. It has been reported that human urine, especially its macromolecular fraction, distinctively prevented calcium oxalate monohydrate (COM) crystal adhesion to tubular cells. This study was designed to find and isolate a specific substance in human urine with a strong inhibitory effect against crystal adhesion. A protein from the urine was purified by two anion exchange chromatography columns and one gel filtration column. The inhibition activity for COM crystal adhesion to Madin-Darby canine kidney cells was determined quantitatively. Amino acid sequence of the protein was analyzed and then subjected to homology search in the GenBank protein database. A specific human urine protein that inhibited the COM crystal adhesion to the cells was isolated and identified. Molecular mass of the protein was approximately 35 kD. The first 20-amino acid sequence from the N-terminal of the purified protein was structurally homologous with the light chain of inter-alpha-trypsin inhibitor, also called bikunin. The isolated bikunin inhibited crystal adhesion at a minimum concentration of 10 ng/ml, and blocked completely at 200 ng/ml. It is concluded that bikunin may contribute to the regulation of crystal adhesion and retention within tubules during kidney stone formation.

  6. Unusual Case of Coexisting Renal Malignancies: Mucinous Tubular and Spindle Cell Carcinoma Kidney With Sarcomatoid Dedifferentiation

    PubMed Central

    Agnihotri, Pragati; Alam, Kiran; Raza, Kashif

    2016-01-01

    Mucinous tubular and spindle cell carcinoma (MTSCC) is a recent entity introduced in the World Health Organization 2004 Classification. It is a tumour of low malignant potential. MTSCC is a subtype of renal cell carcinoma (RCC), which is characterized by a polymorphous histology, wherein the spindled epithelial cell is an inherent carcinomatous component. We report the case of a 57-year-old man presenting with loin pain and dragging sensation. Imaging revealed a large mass arising from the left kidney. Radical nephrectomy was performed, and histopathology revealed spindle cell elements of MTSCC with low-grade cytology, which occasionally blended with tubular structures in variable mucinous stroma admixed with spindle sarcomatoid cells with marked nuclear pleomorphism, associated with significant necrosis and mitoses of up to 5/10 high-power field. A final diagnosis of MTSCC along with high-grade areas consistent with sarcomatoid dedifferentiation was made. Sarcomatoid dedifferentiation has been well documented in various subtypes of RCC, and its presence signifies a worse prognosis in RCC.

  7. The need for genetic study to diagnose some cases of distal renal tubular acidosis.

    PubMed

    Heras Benito, Manuel; Garcia-Gonzalez, Miguel A; Valdenebro Recio, María; Molina Ordás, Álvaro; Callejas Martínez, Ramiro; Rodríguez Gómez, María Astrid; Calle García, Leonardo; Sousa Silva, Lisbeth; Fernández-Reyes Luis, María José

    We describe the case of a young woman who was diagnosed with advanced kidney disease, with an incidental finding of nephrocalcinosis of unknown aetiology, having been found asymptomatic throughout her life. The genetic study by panels of known genes associated with tubulointerstitial disease allowed us to discover autosomal dominant distal renal tubular acidosis associated with a de novo mutation in exon 14 of the SLC4A1 gene, which would have been impossible to diagnose clinically due to the advanced nature of the kidney disease when it was discovered. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  8. Hypokalemic periodic paralysis associated with thyrotoxicosis, renal tubular acidosis and nephrogenic diabetes insipidus.

    PubMed

    Im, Eun Joo; Lee, Jung Min; Kim, Ji Hyun; Chang, Sang Ah; Moon, Sung Dae; Ahn, Yu Bae; Son, Hyun Shik; Cha, Bong Yun; Lee, Kwang Woo; Son, Ho Young

    2010-01-01

    A 19-year-old girl presented at our emergency room with hypokalemic periodic paralysis. She had a thyrotoxic goiter and had experienced three paralytic attacks during the previous 2 years on occasions when she stopped taking antithyroid drugs. In addition to thyrotoxic periodic paralysis (TPP), she had metabolic acidosis, urinary potassium loss, polyuria and polydipsia. Her reduced ability to acidify urine during spontaneous metabolic acidosis was confirmed by detection of coexisting distal renal tubular acidosis (RTA). The polyuria and polydipsia were caused by nephrogenic diabetes insipidus, which was diagnosed using the water deprivation test and vasopressin administration. Her recurrent and frequent paralytic attacks may have been the combined effects of thyrotoxicosis and RTA. Although the paralytic attack did not recur after improving the thyroid function, mild acidosis and nephrogenic DI have been remained subsequently. Patients with TPP, especially females with atypical metabolic features, should be investigated for possible precipitating factors.

  9. Late Metabolic Acidosis Caused by Renal Tubular Acidosis in Acute Salicylate Poisoning.

    PubMed

    Sakai, Norihiro; Hirose, Yasuo; Sato, Nobuhiro; Kondo, Daisuke; Shimada, Yuko; Hori, Yasushi

    2016-01-01

    A 16-year-old man was transferred to our emergency department seven hours after ingesting 486 aspirin tablets. His blood salicylate level was 83.7 mg/dL. He was treated with fluid resuscitation and sodium bicarbonate infusion, and his condition gradually improved, with a decline in the blood salicylate level. However, eight days after admission, he again reported nausea, a venous blood gas revealed metabolic acidosis with a normal anion gap. The blood salicylate level was undetectable, and a urinalysis showed glycosuria, proteinuria and elevated beta-2 microglobulin and n-acetyl glucosamine levels, with a normal urinary pH despite the acidosis. We diagnosed him with relapse of metabolic acidosis caused by renal tubular acidosis.

  10. Successful treatment of proximal renal tubular acidosis and Fanconi syndrome with vitamin D replacement.

    PubMed

    Ali, Syed Ahsan; Tariq, Muhammad

    2016-01-01

    Proximal renal tubular acidosis (RTA), also known as Type II RTA, is characterized by a defect in the ability to reabsorb bicarbonate (HCO 3 ) in the proximal tubule. It is usually associated with generalized dysfunction of the proximal tubule as part of Fanconi syndrome. Very few case reports in the literature support Vitamin D deficiency as a cause of proximal RTA. We present a case of a young female who presented with proximal RTA and Fanconi syndrome and excellently responded to Vitamin D replacement. Thus, work-up for the etiology of proximal RTA should include Vitamin D levels since replacement of this vitamin in those who are deficient can lead to cure of such patients.

  11. Long-term follow-up in distal renal tubular acidosis with sensorineural deafness.

    PubMed

    Peces, R

    2000-11-01

    A 20-year-old man presented with failure to thrive and bilateral genu valgum. On the basis of growth failure, skeletal deformity, hyperchloremic metabolic acidosis with alkaline urine and hypokalemia, nephrocalcinosis, and hearing loss, a diagnosis of distal renal tubular acidosis (DRTA) with sensorineural deafness was made. The genu valgum was treated by corrective osteotomy. Skeletal deformity was corrected and impaired growth improved after sustained therapy of metabolic acidosis with alkali supplementation. During an 8-year follow-up period the patient's glomerular filtration rate remained stable, the nephrocalcinosis did not progress, and his height increased 10 cm. Although nephrolithiasis led to atrophy of the right kidney, at last follow-up, when the patient was 44 years old, his creatinine clearance was 50 ml/min per 1.73 m2 body surface.

  12. Evaluation of the ability of bone marrow derived cells to engraft the kidney and promote renal tubular regeneration in mice following exposure to cisplatin.

    PubMed

    Bataille, Aurélien; Galichon, Pierre; Wetzstein, Morgane; Legouis, David; Vandermeersch, Sophie; Rondeau, Eric; Hertig, Alexandre

    2016-01-01

    It has been suggested that bone marrow derived stem cells have the ability to engraft the kidney and improve the outcome of severe acute kidney injury (AKI) in mice exposed to high doses of cisplatin, providing hope for cancer patients in whom irreversible renal damage occasionally occurs following the use of this highly effective anti-tumor drug. We tested the therapeutic potential of bone marrow derived cells injected during the acute phase (day 3 after cisplatin administration) of experimentally-induced AKI in C57Bl6/J mice, characterized by massive tubular necrosis, apoptosis, and a low proliferation capacity. We failed to show any benefit of bone marrow derived cells versus a regular homogenate of intact renal cells, or normal saline. Using cell tracers and flow cytometry, we demonstrated that bone marrow derived cells did indeed home to the bone marrow of the recipients but failed to settle in the kidney. Conversely, renal cells homed to injured kidneys. However, neither cell therapy protected the animals against cisplatin-induced death. We therefore question the short-term efficacy of bone marrow derived cells used to repair established injuries of the tubular epithelium.

  13. A tissue-specific role for Nlrp3 in tubular epithelial repair after renal ischemia/reperfusion.

    PubMed

    Bakker, Pieter J; Butter, Loes M; Claessen, Nike; Teske, Gwendoline J D; Sutterwala, Fayyaz S; Florquin, Sandrine; Leemans, Jaklien C

    2014-07-01

    Ischemia/reperfusion injury is a major cause of acute kidney injury. Improving renal repair would represent a therapeutic strategy to prevent renal dysfunction. The innate immune receptor Nlrp3 is involved in tissue injury, inflammation, and fibrosis; however, its role in repair after ischemia/reperfusion is unknown. We address the role of Nlrp3 in the repair phase of renal ischemia/reperfusion and investigate the relative contribution of leukocyte- versus renal-associated Nlrp3 by studying bone marrow chimeric mice. We found that Nlrp3 expression was most profound during the repair phase. Although Nlrp3 expression was primarily expressed by leukocytes, both leukocyte- and renal-associated Nlrp3 was detrimental to renal function after ischemia/reperfusion. The Nlrp3-dependent cytokine IL-1β remained unchanged in kidneys of all mice. Leukocyte-associated Nlrp3 negatively affected tubular apoptosis in mice that lacked Nlrp3 expression on leukocytes, which correlated with reduced macrophage influx. Nlrp3-deficient (Nlrp3KO) mice with wild-type bone marrow showed an improved repair response, as seen by a profound increase in proliferating tubular epithelium, which coincided with increased hepatocyte growth factor expression. In addition, Nlrp3KO tubular epithelial cells had an increased repair response in vitro, as seen by an increased ability of an epithelial monolayer to restore its structural integrity. In conclusion, Nlrp3 shows a tissue-specific role in which leukocyte-associated Nlrp3 is associated with tubular apoptosis, whereas renal-associated Nlrp3 impaired wound healing. Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  14. Auxin induces cell proliferation in an experimental model of mammalian renal tubular epithelial cells.

    PubMed

    Cernaro, Valeria; Medici, Maria Antonietta; Leonello, Giuseppa; Buemi, Antoine; Kohnke, Franz Heinrich; Villari, Antonino; Santoro, Domenico; Buemi, Michele

    2015-06-01

    Indole-3-acetic acid is the main auxin produced by plants and plays a key role in the plant growth and development. This hormone is also present in humans where it is considered as a uremic toxin deriving from tryptophan metabolism. However, beyond this peculiar aspect, the involvement of auxin in human pathophysiology has not been further investigated. Since it is a growth hormone, we evaluated its proliferative properties in an in vitro model of mammalian renal tubular epithelial cells. We employed an experimental model of renal tubular epithelial cells belonging to the LLC-PK1 cell line that is derived from the kidney of healthy male pig. Growth effects of auxin against LLC-PK1 cell lines were determined by a rapid colorimetric assay. Increasing concentrations of auxin (to give a final concentration from 1 to 1000 ng/mL) were added and microplates were incubated for 72 h. Each auxin concentration was assayed in four wells and repeated four times. Cell proliferation significantly increased, compared to control cells, 72 h after addition of auxin to cultured LLC-PK1 cells. Statistically significant values were observed when 100 ng/mL (p < 0.01) and 1000 ng/mL (p < 0.05) were used. In conclusion, auxin influences cell growth not only in plants, where its role is well documented, but also in mammalian cell lines. This observation opens new scenarios in the field of tissue regeneration and may stimulate a novel line of research aiming at investigating whether this hormone really influences human physiology and pathophysiology and in particular, kidney regeneration.

  15. Mesenchymal Stromal Cells Epithelial Transition Induced by Renal Tubular Cells-Derived Extracellular Vesicles.

    PubMed

    Chiabotto, Giulia; Bruno, Stefania; Collino, Federica; Camussi, Giovanni

    2016-01-01

    Mesenchymal-epithelial interactions play an important role in renal tubular morphogenesis and in maintaining the structure of the kidney. The aim of this study was to investigate whether extracellular vesicles (EVs) produced by human renal proximal tubular epithelial cells (RPTECs) may induce mesenchymal-epithelial transition of bone marrow-derived mesenchymal stromal cells (MSCs). To test this hypothesis, we characterized the phenotype and the RNA content of EVs and we evaluated the in vitro uptake and activity of EVs on MSCs. MicroRNA (miRNA) analysis suggested the possible implication of the miR-200 family carried by EVs in the epithelial commitment of MSCs. Bone marrow-derived MSCs were incubated with EVs, or RPTEC-derived total conditioned medium, or conditioned medium depleted of EVs. As a positive control, MSCs were co-cultured in a transwell system with RPTECs. Epithelial commitment of MSCs was assessed by real time PCR and by immunofluorescence analysis of cellular expression of specific mesenchymal and epithelial markers. After one week of incubation with EVs and total conditioned medium, we observed mesenchymal-epithelial transition in MSCs. Stimulation with conditioned medium depleted of EVs did not induce any change in mesenchymal and epithelial gene expression. Since EVs were found to contain the miR-200 family, we transfected MSCs using synthetic miR-200 mimics. After one week of transfection, mesenchymal-epithelial transition was induced in MSCs. In conclusion, miR-200 carrying EVs released from RPTECs induce the epithelial commitment of MSCs that may contribute to their regenerative potential. Based on experiments of MSC transfection with miR-200 mimics, we suggested that the miR-200 family may be involved in mesenchymal-epithelial transition of MSCs.

  16. Mesenchymal Stromal Cells Epithelial Transition Induced by Renal Tubular Cells-Derived Extracellular Vesicles

    PubMed Central

    Chiabotto, Giulia; Bruno, Stefania; Collino, Federica

    2016-01-01

    Mesenchymal-epithelial interactions play an important role in renal tubular morphogenesis and in maintaining the structure of the kidney. The aim of this study was to investigate whether extracellular vesicles (EVs) produced by human renal proximal tubular epithelial cells (RPTECs) may induce mesenchymal-epithelial transition of bone marrow-derived mesenchymal stromal cells (MSCs). To test this hypothesis, we characterized the phenotype and the RNA content of EVs and we evaluated the in vitro uptake and activity of EVs on MSCs. MicroRNA (miRNA) analysis suggested the possible implication of the miR-200 family carried by EVs in the epithelial commitment of MSCs. Bone marrow-derived MSCs were incubated with EVs, or RPTEC-derived total conditioned medium, or conditioned medium depleted of EVs. As a positive control, MSCs were co-cultured in a transwell system with RPTECs. Epithelial commitment of MSCs was assessed by real time PCR and by immunofluorescence analysis of cellular expression of specific mesenchymal and epithelial markers. After one week of incubation with EVs and total conditioned medium, we observed mesenchymal-epithelial transition in MSCs. Stimulation with conditioned medium depleted of EVs did not induce any change in mesenchymal and epithelial gene expression. Since EVs were found to contain the miR-200 family, we transfected MSCs using synthetic miR-200 mimics. After one week of transfection, mesenchymal-epithelial transition was induced in MSCs. In conclusion, miR-200 carrying EVs released from RPTECs induce the epithelial commitment of MSCs that may contribute to their regenerative potential. Based on experiments of MSC transfection with miR-200 mimics, we suggested that the miR-200 family may be involved in mesenchymal-epithelial transition of MSCs. PMID:27409796

  17. Cadmium activates extracellular signal-regulated kinase 5 in HK-2 human renal proximal tubular cells

    SciTech Connect

    Kondo, Mio; Inamura, Hisako; Matsumura, Ken-ichi; Matsuoka, Masato

    2012-05-11

    Highlights: Black-Right-Pointing-Pointer Cadmium exposure induces ERK5 phosphorylation in HK-2 renal proximal tubular cells. Black-Right-Pointing-Pointer BIX02189 treatment suppresses cadmium-induced ERK5 but not ERK1/2 phosphorylation. Black-Right-Pointing-Pointer BIX02189 treatment suppresses cadmium-induced CREB and c-Fos phosphorylation. Black-Right-Pointing-Pointer ERK5 activation by cadmium exposure may play an anti-apoptotic role in HK-2 cells. -- Abstract: We examined the effects of cadmium chloride (CdCl{sub 2}) exposure on the phosphorylation and functionality of extracellular signal-regulated kinase 5 (ERK5), a recently identified member of the mitogen-activated protein kinase (MAPK) family, in HK-2 human renal proximal tubular cells. Following exposure to CdCl{sub 2}, ERK5 phosphorylation increased markedly, but the level of total ERK5 was unchanged. ERK5 phosphorylation following CdCl{sub 2} exposure was rapid and transient, similar to the time course of ERK1/2 phosphorylation. Treatment of HK-2 cells with the MAPK/ERK kinase 5 inhibitor, BIX02189, suppressed CdCl{sub 2}-induced ERK5 but not ERK1/2 phosphorylation. The CdCl{sub 2}-induced increase of phosphorylated cAMP response element-binding protein (CREB) and activating transcription factor-1 (ATF-1), as well as the accumulation of mobility-shifted c-Fos protein, were suppressed by BIX02189 treatment. Furthermore, BIX02189 treatment enhanced cleavage of poly(ADP-ribose) polymerase and increased the level of cytoplasmic nucleosomes in HK-2 cells exposed to CdCl{sub 2}. These findings suggest that ERK5 pathway activation by CdCl{sub 2} exposure might induce the phosphorylation of cell survival-transcription factors, such as CREB, ATF-1, and c-Fos, and may exert a partial anti-apoptotic role in HK-2 cells.

  18. Naproxen-induced Ca2+ movement and death in MDCK canine renal tubular cells.

    PubMed

    Cheng, H-H; Chou, C-T; Sun, T-K; Liang, W-Z; Cheng, J-S; Chang, H-T; Tseng, H-W; Kuo, C-C; Chen, F-A; Kuo, D-H; Shieh, P; Jan, C-R

    2015-11-01

    Naproxen is an anti-inflammatory drug that affects cellular calcium ion (Ca(2+)) homeostasis and viability in different cells. This study explored the effect of naproxen on [Ca(2+)](i) and viability in Madin-Darby canine kidney cells (MDCK) canine renal tubular cells. At concentrations between 50 μM and 300 μM, naproxen induced [Ca(2+)](i) rises in a concentration-dependent manner. This Ca(2+) signal was reduced partly when extracellular Ca(2+) was removed. The Ca(2+) signal was inhibited by a Ca(2+) channel blocker nifedipine but not by store-operated Ca(2+) channel inhibitors (econazole and SKF96365), a protein kinase C (PKC) activator phorbol 12-myristate 13-acetate, and a PKC inhibitor GF109203X. In Ca(2+)-free medium, pretreatment with 2,5-di-tert-butylhydroquinone or thapsigargin, an inhibitor of endoplasmic reticulum Ca(2+) pumps, partly inhibited naproxen-induced Ca(2+) signal. Inhibition of phospholipase C with U73122 did not alter naproxen-evoked [Ca(2+)](i) rises. At concentrations between 15 μM and 30 μM, naproxen killed cells in a concentration-dependent manner, which was not reversed by prechelating cytosolic Ca(2+) with the acetoxymethyl ester of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl. Annexin V/propidium iodide staining data suggest that naproxen induced apoptosis. Together, in MDCK renal tubular cells, naproxen induced [Ca(2+)](i) rises by inducing Ca(2+) release from multiple stores that included the endoplasmic reticulum and Ca(2+) entry via nifedipine-sensitive Ca(2+) channels. Naproxen induced cell death that involved apoptosis. © The Author(s) 2015.

  19. The small GTPase Cdc42 is necessary for primary ciliogenesis in renal tubular epithelial cells.

    PubMed

    Zuo, Xiaofeng; Fogelgren, Ben; Lipschutz, Joshua H

    2011-06-24

    Primary cilia are found on many epithelial cell types, including renal tubular epithelial cells, where they participate in flow sensing. Disruption of cilia function has been linked to the pathogenesis of polycystic kidney disease. We demonstrated previously that the exocyst, a highly conserved eight-protein membrane trafficking complex, localizes to primary cilia of renal tubular epithelial cells, is required for ciliogenesis, biochemically and genetically interacts with polycystin-2 (the protein product of the polycystic kidney disease 2 gene), and, when disrupted, results in MAPK pathway activation both in vitro and in vivo. The small GTPase Cdc42 is a candidate for regulation of the exocyst at the primary cilium. Here, we demonstrate that Cdc42 biochemically interacts with Sec10, a crucial component of the exocyst complex, and that Cdc42 colocalizes with Sec10 at the primary cilium. Expression of dominant negative Cdc42 and shRNA-mediated knockdown of both Cdc42 and Tuba, a Cdc42 guanine nucleotide exchange factor, inhibit ciliogenesis in Madin-Darby canine kidney cells. Furthermore, exocyst Sec8 and polycystin-2 no longer localize to primary cilia or the ciliary region following Cdc42 and Tuba knockdown. We also show that Sec10 directly interacts with Par6, a member of the Par complex that itself directly interacts with Cdc42. Finally, we show that Cdc42 knockdown results in activation of the MAPK pathway, something observed in cells with dysfunctional primary cilia. These data support a model in which Cdc42 localizes the exocyst to the primary cilium, whereupon the exocyst then targets and docks vesicles carrying proteins necessary for ciliogenesis.

  20. The Small GTPase Cdc42 Is Necessary for Primary Ciliogenesis in Renal Tubular Epithelial Cells*

    PubMed Central

    Zuo, Xiaofeng; Fogelgren, Ben; Lipschutz, Joshua H.

    2011-01-01

    Primary cilia are found on many epithelial cell types, including renal tubular epithelial cells, where they participate in flow sensing. Disruption of cilia function has been linked to the pathogenesis of polycystic kidney disease. We demonstrated previously that the exocyst, a highly conserved eight-protein membrane trafficking complex, localizes to primary cilia of renal tubular epithelial cells, is required for ciliogenesis, biochemically and genetically interacts with polycystin-2 (the protein product of the polycystic kidney disease 2 gene), and, when disrupted, results in MAPK pathway activation both in vitro and in vivo. The small GTPase Cdc42 is a candidate for regulation of the exocyst at the primary cilium. Here, we demonstrate that Cdc42 biochemically interacts with Sec10, a crucial component of the exocyst complex, and that Cdc42 colocalizes with Sec10 at the primary cilium. Expression of dominant negative Cdc42 and shRNA-mediated knockdown of both Cdc42 and Tuba, a Cdc42 guanine nucleotide exchange factor, inhibit ciliogenesis in Madin-Darby canine kidney cells. Furthermore, exocyst Sec8 and polycystin-2 no longer localize to primary cilia or the ciliary region following Cdc42 and Tuba knockdown. We also show that Sec10 directly interacts with Par6, a member of the Par complex that itself directly interacts with Cdc42. Finally, we show that Cdc42 knockdown results in activation of the MAPK pathway, something observed in cells with dysfunctional primary cilia. These data support a model in which Cdc42 localizes the exocyst to the primary cilium, whereupon the exocyst then targets and docks vesicles carrying proteins necessary for ciliogenesis. PMID:21543338

  1. Autosomal dominant osteopetrosis associated with renal tubular acidosis is due to a CLCN7 mutation

    PubMed Central

    Piret, Sian E.; Gorvin, Caroline M.; Trinh, Anne; Taylor, John; Lise, Stefano; Taylor, Jenny C.; Ebeling, Peter R.

    2016-01-01

    The aim of this study was to identify the causative mutation in a family with an unusual presentation of autosomal dominant osteopetrosis (OPT), proximal renal tubular acidosis (RTA), renal stones, epilepsy, and blindness, a combination of features not previously reported. We undertook exome sequencing of one affected and one unaffected family member, followed by targeted analysis of known candidate genes to identify the causative mutation. This identified a missense mutation (c.643G>A; p.Gly215Arg) in the gene encoding the chloride/proton antiporter 7 (gene CLCN7, protein CLC‐7), which was confirmed by amplification refractory mutation system (ARMS)‐PCR, and to be present in the three available patients. CLC‐7 mutations are known to cause autosomal dominant OPT type 2, also called Albers–Schonberg disease, which is characterized by osteosclerosis, predominantly of the spine, pelvis and skull base, resulting in bone fragility and fractures. Albers–Schonberg disease is not reported to be associated with RTA, but autosomal recessive OPT type 3 (OPTB3) with RTA is associated with carbonic anhydrase type 2 (CA2) mutations. No mutations were detected in CA2 or any other genes known to cause proximal RTA. Neither CLCN7 nor CA2 mutations have previously been reported to be associated with renal stones or epilepsy. Thus, we identified a CLCN7 mutation in a family with autosomal dominant osteopetrosis, RTA, renal stones, epilepsy, and blindness. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc. PMID:27540713

  2. Effect of diuretics on renal tubular transport of calcium and magnesium.

    PubMed

    Alexander, R Todd; Dimke, Henrik

    2017-06-01

    Calcium (Ca(2+)) and Magnesium (Mg(2+)) reabsorption along the renal tubule is dependent on distinct trans- and paracellular pathways. Our understanding of the molecular machinery involved is increasing. Ca(2+) and Mg(2+) reclamation in kidney is dependent on a diverse array of proteins, which are important for both forming divalent cation-permeable pores and channels, but also for generating the necessary driving forces for Ca(2+) and Mg(2+) transport. Alterations in these molecular constituents can have profound effects on tubular Ca(2+) and Mg(2+) handling. Diuretics are used to treat a large range of clinical conditions, but most commonly for the management of blood pressure and fluid balance. The pharmacological targets of diuretics generally directly facilitate sodium (Na(+)) transport, but also indirectly affect renal Ca(2+) and Mg(2+) handling, i.e., by establishing a prerequisite electrochemical gradient. It is therefore not surprising that substantial alterations in divalent cation handling can be observed following diuretic treatment. The effects of diuretics on renal Ca(2+) and Mg(2+) handling are reviewed in the context of the present understanding of basal molecular mechanisms of Ca(2+) and Mg(2+) transport. Acetazolamide, osmotic diuretics, Na(+)/H(+) exchanger (NHE3) inhibitors, and antidiabetic Na(+)/glucose cotransporter type 2 (SGLT) blocking compounds, target the proximal tubule, where paracellular Ca(2+) transport predominates. Loop diuretics and renal outer medullary K(+) (ROMK) inhibitors block thick ascending limb transport, a segment with significant paracellular Ca(2+) and Mg(2+) transport. Thiazides target the distal convoluted tubule; however, their effect on divalent cation transport is not limited to that segment. Finally, potassium-sparing diuretics, which inhibit electrogenic Na(+) transport at distal sites, can also affect divalent cation transport. Copyright © 2017 the American Physiological Society.

  3. Complicated pregnancies in inherited distal renal tubular acidosis: importance of acid-base balance.

    PubMed

    Seeger, Harald; Salfeld, Peter; Eisel, Rüdiger; Wagner, Carsten A; Mohebbi, Nilufar

    2017-06-01

    Inherited distal renal tubular acidosis (dRTA) is caused by impaired urinary acid excretion resulting in hyperchloremic metabolic acidosis. Although the glomerular filtration rate (GFR) is usually preserved, and hypertension and overt proteinuria are absent, it has to be considered that patients with dRTA also suffer from chronic kidney disease (CKD) with an increased risk for adverse pregnancy-related outcomes. Typical complications of dRTA include severe hypokalemia leading to cardiac arrhythmias and paralysis, nephrolithiasis and nephrocalcinosis. Several physiologic changes occur in normal pregnancy including alterations in acid-base and electrolyte homeostasis as well as in GFR. However, data on pregnancy in women with inherited dRTA are scarce. We report the course of pregnancy in three women with hereditary dRTA. Complications observed were severe metabolic acidosis, profound hypokalemia aggravated by hyperemesis gravidarum, recurrent urinary tract infection (UTI) and ureteric obstruction leading to renal failure. However, the outcome of all five pregnancies (1 pregnancy each for mothers n. 1 and 2; 3 pregnancies for mother n. 3) was excellent due to timely interventions. Our findings highlight the importance of close nephrologic monitoring of women with inherited dRTA during pregnancy. In addition to routine assessment of creatinine and proteinuria, caregivers should especially focus on acid-base status, plasma potassium and urinary tract infections. Patients should be screened for renal obstruction in the case of typical symptoms, UTI or renal failure. Furthermore, genetic identification of the underlying mutation may (a) support early nephrologic referral during pregnancy and a better management of the affected woman, and (b) help to avoid delayed diagnosis and reduce complications in affected newborns.

  4. Human CD133+ Renal Progenitor Cells Induce Erythropoietin Production and Limit Fibrosis After Acute Tubular Injury

    PubMed Central

    Aggarwal, Shikhar; Grange, Cristina; Iampietro, Corinne; Camussi, Giovanni; Bussolati, Benedetta

    2016-01-01

    Persistent alterations of the renal tissue due to maladaptive repair characterize the outcome of acute kidney injury (AKI), despite a clinical recovery. Acute damage may also limit the renal production of erythropoietin, with impairment of the hemopoietic response to ischemia and possible lack of its reno-protective action. We aimed to evaluate the effect of a cell therapy using human CD133+ renal progenitor cells on maladaptive repair and fibrosis following AKI in a model of glycerol-induced rhabdomyolysis. In parallel, we evaluated the effect of CD133+ cells on erythropoietin production. Administration of CD133+ cells promoted the restoration of the renal tissue, limiting the presence of markers of injury and pro-inflammatory molecules. In addition, it promoted angiogenesis and protected against fibrosis up to day 60. No effect of dermal fibroblasts was observed. Treatment with CD133+ cells, but not with PBS or fibroblasts, limited anemia and increased erythropoietin levels both in renal tissue and in circulation. Finally, CD133+ cells contributed to the local production of erythropoietin, as observed by detection of circulating human erythropoietin. CD133+ cells appear therefore an effective source for cell repair, able to restore renal functions, including erythropoietin release, and to limit long term maldifferentiation and fibrosis. PMID:27853265

  5. Stem cell conditioned culture media attenuated albumin-induced epithelial-mesenchymal transition in renal tubular cells.

    PubMed

    Hu, Junping; Zhu, Qing; Li, Pin-Lan; Wang, Weili; Yi, Fan; Li, Ningjun

    2015-01-01

    Proteinuria-induced epithelial-mesenchymal transition (EMT) plays an important role in progressive renal tubulointerstitial fibrosis in chronic renal disease. Stem cell therapy has been used for different diseases. Stem cell conditioned culture media (SCM) exhibits similar beneficial effects as stem cell therapy. The present study tested the hypothesis that SCM inhibits albumin-induced EMT in cultured renal tubular cells. Rat renal tubular cells were treated with/without albumin (20 µmg/ml) plus SCM or control cell media (CCM). EMT markers and inflammatory factors were measured by Western blot and fluorescent images. Albumin induced EMT as shown by significant decreases in levels of epithelial marker E-cadherin, increases in mesenchymal markers fibroblast-specific protein 1 and α-smooth muscle actin, and elevations in collagen I. SCM inhibited all these changes. Meanwhile, albumin induced NF-κB translocation from cytosol into nucleus and that SCM blocked the nuclear translocation of NF-κB. Albumin also increased the levels of pro-inflammatory factor monocyte chemoattractant protein-1 (MCP)-1 by nearly 30 fold compared with control. SCM almost abolished albumin-induced increase of MCP-1. These results suggest that SCM attenuated albumin-induced EMT in renal tubular cells via inhibiting activation of inflammatory factors, which may serve as a new therapeutic approach for chronic kidney diseases. © 2015 S. Karger AG, Basel.

  6. [Effects of Rhein on the hypertrophy of renal proximal tubular epithelial cells induced by high glucose and angiotensin II in rats].

    PubMed

    Yu, De-Qian; Gao, Yuan; Liu, Xiao-Hong

    2010-04-01

    To explore the effect of Rhein on the hypertrophy of renal proximal tubular epithelial cells induced by high glucose and angiotensin II in rats. Studies were performed on anesthetized SD rats. Renal proximal tubular were gained by microdissection and cultured in RPMI-1640 medium. The cell types were identified by immunocytochemistry. The renal proximal tubular epithelial cells were incubated with high glucose (30 mmol/L) and angiotensin II (10(-7) mol/L) to induce the hypertrophy of cells. To observe the effect of Rhein on hypertrophy induced by high glucose and angiotensin II, renal proximal tubular epithelial cells were cultured with different concentrations of Rhein (30, 15, 5 mg/L) for 72 h, then cell size, 3H-leucine incorporation, and cellular protein content were detected to observe the changes. High glucose (30 mmol/L) and Ang II (10(-7) mol/L) induced hypertrophy of renal proximal tubular epithelial cells result in, cell size, 3H-leucine incorporation and cellular protein content increased significantly. On the contrary, Rhein inhibited the hypertrophy of renal proximal tubular epithelial cells induced by high glucose and Angiotensin II. Rhein 30 mg/L significantly decreased cell size, 3H-leucine incorporation and cellular protein content. Rhein 15 mg/L decreased 3H-leucine incorporation and cellular protein content. Rhein 5 mg/L decreased cellular protein content. Rhein can inhibit the hypertrophy of renal proximal tubular epithelial cells induced by high glucose and Angiotensin II in rats.

  7. Tubular cell dedifferentiation and peritubular inflammation are coupled by the transcription regulator Id1 in renal fibrogenesis

    PubMed Central

    Li, Yingjian; Wen, Xiaoyan; Liu, Youhua

    2011-01-01

    During renal fibrogenesis, tubular epithelial-mesenchymal transition is closely associated with peritubular inflammation; however, it is not clear whether these two processes are connected. We previously identified the inhibitor of differentiation-1 (Id1), a dominant negative antagonist of basic helix-loop-helix transcription factors, as a major trigger of tubular cell dedifferentiation after injury. Id1 was induced selectively in degenerated proximal tubule and collecting duct epithelia after injury and was present in both the cytoplasm and nucleus, suggesting shuttling between these two compartments. Interestingly, the upregulation of Id1 was associated with peritubular inflammation in mouse and human nephropathies. In vitro, Id1 potentiated NF-κB signaling and augmented RANTES expression in kidney epithelial cells, which led to an enhanced recruitment of inflammatory cells. Id1 also induced Snail1 expression and triggered tubular epithelial dedifferentiation. In vivo, genetic ablation of Id1 in mice reduced peritubular inflammation and decreased tubular expression of RANTES following ureteral obstruction. Mice lacking Id1 were also protected against myofibroblast activation and matrix expression, leading to a reduced total collagen deposition in obstructive nephropathy. Thus, these results indicate that Id1 shuttles between nucleus and cytoplasm and promotes peritubular inflammation and tubular epithelial dedifferentiation, suggesting that these two events are intrinsically coupled during renal fibrogenesis. PMID:22278018

  8. Filterable plasma concentration, glomerular filtration, tubular balance, and renal clearance of heavy metals and organic substances in metal workers

    SciTech Connect

    Araki, S.; Aono, H.; Yokoyama, K.; Murata, K.

    1986-07-01

    To estimate filterable plasma concentration (FPx), glomerular filtration, tubular balance, and renal clearance of heavy metals and organic substances, the authors examined the regressions of the 24-hr urinary excretion on glomerular filtration rate (GFR, 24-hr endogenous creatinine (Cn) clearance) in 19 gun-metal foundry workers with blood lead (Pb) concentrations of 25-59 micrograms/dl. It was estimated that the proportion of FPx to total plasma concentration was on average 15, 7, 3, 0.6, 0.06, and 0.008% for Pb, cadmium (Cd), manganese (Mn), zinc (Zn), chromium (Cr), and copper (Cu), respectively. The estimated FPx value was 2.8 X 10(2), 4, 0.08, and 2.8 X 10(4) micrograms/dl for hippuric acid (HA), delta-aminolevulinic acid (ALA), coproporphyrin (CP), and total urinary solutes (TUS), respectively. The estimated glomerular filtration was significantly greater than the zero level for all substances but inorganic mercury (Hg). Similarly, the estimated net tubular secretion was significantly greater than the zero level for Cr, Cu, and TUS; the net tubular reabsorption was significantly greater than the zero level for Pb, ALA, and CP. The renal clearance of ''filterable'' plasma substance was significantly greater than GFR for Cr, Cu, and TUS and was significantly smaller for Pb, ALA, and CP. Thus the renal excretory mechanisms of substances were classified into four major categories: glomerular filtration for Cd, Mn, Zn, HA, and Cn; glomerular filtration and net tubular secretion for Cr, Cu, and TUS; glomerular filtration and net tubular reabsorption for Pb, ALA, and CP; and no glomerular filtration, i.e., suspected tubular secretion, for Hg.

  9. Prohibitin is associated with antioxidative protection in hypoxia/reoxygenation-induced renal tubular epithelial cell injury

    NASA Astrophysics Data System (ADS)

    Zhou, Tian-Biao; Qin, Yuan-Han; Lei, Feng-Ying; Huang, Wei-Fang; Drummen, Gregor P. C.

    2013-11-01

    Prohibitin is an evolutionary conserved and pleiotropic protein that has been implicated in various cellular functions, including proliferation, tumour suppression, apoptosis, transcription, and mitochondrial protein folding. We recently demonstrated that prohibitin downregulation results in increased renal interstitial fibrosis. Here we investigated the role of oxidative stress and prohibitin expression in a hypoxia/reoxygenation injury system in renal tubular epithelial cells with lentivirus-based delivery vectors to knockdown or overexpress prohibitin. Our results show that increased prohibitin expression was negatively correlated with reactive oxygen species, malon dialdehyde, transforming-growth-factor-β1, collagen-IV, fibronectin, and apoptosis (r = -0.895, -0.764, -0.798, -0.826, -0.817, -0.735 each P < 0.01), but positively correlated with superoxide dismutase, glutathione and mitochondrial membrane potential (r = 0.807, 0.815, 0.739; each P < 0.01). We postulate that prohibitin acts as a positive regulator of mechanisms that counteract oxidative stress and extracellular matrix accumulation and therefore has an antioxidative effect.

  10. Effect of berberine on the renal tubular epithelial-to-mesenchymal transition by inhibition of the Notch/snail pathway in diabetic nephropathy model KKAy mice

    PubMed Central

    Yang, Guannan; Zhao, Zongjiang; Zhang, Xinxue; Wu, Amin; Huang, Yawei; Miao, Yonghui; Yang, Meijuan

    2017-01-01

    Renal tubular epithelial-to-mesenchymal transition (EMT) and renal tubular interstitial fibrosis are the main pathological changes of diabetic nephropathy (DN), which is a common cause of end-stage renal disease. Previous studies have suggested that berberine (BBR) has antifibrotic effects in the kidney and can reduce apoptosis and inhibit the EMT of podocytes in DN. However, the effect of BBR on the renal tubular EMT in DN and its mechanisms of action are unknown. This study was performed to explore the effects of BBR on the renal tubular EMT and the molecular mechanisms of BBR in DN model KKAy mice and on the high glucose (HG)-induced EMT in mouse renal tubular epithelial cells. Our results showed that, relative to the model mice, the mice in the treatment group had an improved general state and reduced blood glucose and 24-h urinary protein levels. Degradation of renal function was ameliorated by BBR. We also observed the protective effects of BBR on renal structural changes, including normalization of an index of renal interstitial fibrosis and kidney weight/body weight. Moreover, BBR suppressed the activation of the Notch/snail pathway and upregulated the α-SMA and E-cadherin levels in DN model KKAy mice. BBR was further found to prevent HG-induced EMT events and to inhibit the HG-induced expression of Notch pathway members and snail1 in mouse renal tubular epithelial cells. Our findings indicate that BBR has a therapeutic effect on DN, including its inhibition of the renal tubular EMT and renal interstitial fibrosis. Furthermore, the BBR-mediated EMT inhibition occurs through Notch/snail pathway regulation. PMID:28408805

  11. Overexpression of E2A proteins induces epithelial-mesenchymal transition in human renal proximal tubular epithelial cells suggesting a potential role in renal fibrosis.

    PubMed

    Slattery, Craig; McMorrow, Tara; Ryan, Michael P

    2006-07-24

    Epithelial-mesenchymal transition (EMT), a process whereby renal tubular epithelial cells lose phenotype and gain fibroblast-like characteristics, has been demonstrated to contribute significantly to the development of renal fibrosis. The immunosuppressant cyclosporine A (CsA) has been shown to induce renal fibrosis, a major complication of CsA therapy. The mechanisms that drive CsA-induced fibrosis remain undefined, however, CsA has been demonstrated to induce EMT in human renal proximal tubular epithelial cells (RPTEC). E2A transcription factors were identified as being upregulated by CsA treatment. To further examine the role of E2A proteins in EMT, E12 and E47 were overexpressed, alone and in combination, in human RPTEC. Both E12 and E47 elicited EMT effects on tubular epithelial cells with E47 more potent in inducing the fibroblast-like phenotype. These results indicate the important role of the E2A gene products in the progression of CsA-induced EMT and provide novel insights into CsA-induced renal fibrosis.

  12. Renal tubular NEDD4-2 deficiency causes NCC-mediated salt-dependent hypertension.

    PubMed

    Ronzaud, Caroline; Loffing-Cueni, Dominique; Hausel, Pierrette; Debonneville, Anne; Malsure, Sumedha Ram; Fowler-Jaeger, Nicole; Boase, Natasha A; Perrier, Romain; Maillard, Marc; Yang, Baoli; Stokes, John B; Koesters, Robert; Kumar, Sharad; Hummler, Edith; Loffing, Johannes; Staub, Olivier

    2013-02-01

    The E3 ubiquitin ligase NEDD4-2 (encoded by the Nedd4L gene) regulates the amiloride-sensitive epithelial Na+ channel (ENaC/SCNN1) to mediate Na+ homeostasis. Mutations in the human β/γENaC subunits that block NEDD4-2 binding or constitutive ablation of exons 6-8 of Nedd4L in mice both result in salt-sensitive hypertension and elevated ENaC activity (Liddle syndrome). To determine the role of renal tubular NEDD4-2 in adult mice, we generated tetracycline-inducible, nephron-specific Nedd4L KO mice. Under standard and high-Na+ diets, conditional KO mice displayed decreased plasma aldosterone but normal Na+/K+ balance. Under a high-Na+ diet, KO mice exhibited hypercalciuria and increased blood pressure, which were reversed by thiazide treatment. Protein expression of βENaC, γENaC, the renal outer medullary K+ channel (ROMK), and total and phosphorylated thiazide-sensitive Na+Cl- cotransporter (NCC) levels were increased in KO kidneys. Unexpectedly, Scnn1a mRNA, which encodes the αENaC subunit, was reduced and proteolytic cleavage of αENaC decreased. Taken together, these results demonstrate that loss of NEDD4-2 in adult renal tubules causes a new form of mild, salt-sensitive hypertension without hyperkalemia that is characterized by upregulation of NCC, elevation of β/γENaC, but not αENaC, and a normal Na+/K+ balance maintained by downregulation of ENaC activity and upregulation of ROMK.

  13. AM251 Suppresses Epithelial-Mesenchymal Transition of Renal Tubular Epithelial Cells.

    PubMed

    Yoshinaga, Tomoyo; Uwabe, Kenichiro; Naito, Shoichi; Higashino, Kenichi; Nakano, Toru; Numata, Yoshito; Kihara, Akio

    2016-01-01

    Epithelial-mesenchymal transition (EMT) of renal tubular epithelial cells is one of the causative mechanisms of kidney fibrosis. In our study, we screened lipophilic compounds using a lipid library including approximately 200 lipids to identify those that suppressed EMT induced by a transforming growth factor (TGF)-β1 stimulus. Initial screening was performed with the immortalized HK-2 renal tubule epithelial cell line. The most promising compounds were further tested in RPTEC primary renal tubule epithelial cells. We found that the synthetic lipid AM251 suppressed two hallmark events associated with EMT, the upregulation of collagen 1A1 (COL1A1) and downregulation of E-cadherin. Though AM251 is known to act as an antagonist for the cannabinoid receptor type 1 (CB1) and an agonist for the G protein-coupled receptor 55 (GRP55), the suppression of EMT by AM251 was not mediated through either receptor. Microarray analyses revealed that AM251 inhibited induction of several EMT transcription factors such as SNAIL1, which is the key inducer of EMT, and the AP-1 transcription factors FOSB and JUNB. Activation of SMAD2/3 and p38 mitogen-activated protein kinase (MAPK) was inhibited by AM251, with greater inhibition of the latter, indicating that AM251 acted upstream of SMAD/p38 MAPK in the TGF-β signaling pathway. Our findings regarding the effects of AM251 on the TGF-β signaling pathway may inform development of a novel therapeutic agent suppressing EMT, thus preventing kidney fibrosis.

  14. AM251 Suppresses Epithelial-Mesenchymal Transition of Renal Tubular Epithelial Cells

    PubMed Central

    Yoshinaga, Tomoyo; Uwabe, Kenichiro; Naito, Shoichi; Higashino, Kenichi; Nakano, Toru; Numata, Yoshito

    2016-01-01

    Epithelial-mesenchymal transition (EMT) of renal tubular epithelial cells is one of the causative mechanisms of kidney fibrosis. In our study, we screened lipophilic compounds using a lipid library including approximately 200 lipids to identify those that suppressed EMT induced by a transforming growth factor (TGF)-β1 stimulus. Initial screening was performed with the immortalized HK-2 renal tubule epithelial cell line. The most promising compounds were further tested in RPTEC primary renal tubule epithelial cells. We found that the synthetic lipid AM251 suppressed two hallmark events associated with EMT, the upregulation of collagen 1A1 (COL1A1) and downregulation of E-cadherin. Though AM251 is known to act as an antagonist for the cannabinoid receptor type 1 (CB1) and an agonist for the G protein-coupled receptor 55 (GRP55), the suppression of EMT by AM251 was not mediated through either receptor. Microarray analyses revealed that AM251 inhibited induction of several EMT transcription factors such as SNAIL1, which is the key inducer of EMT, and the AP-1 transcription factors FOSB and JUNB. Activation of SMAD2/3 and p38 mitogen-activated protein kinase (MAPK) was inhibited by AM251, with greater inhibition of the latter, indicating that AM251 acted upstream of SMAD/p38 MAPK in the TGF-β signaling pathway. Our findings regarding the effects of AM251 on the TGF-β signaling pathway may inform development of a novel therapeutic agent suppressing EMT, thus preventing kidney fibrosis. PMID:27936102

  15. Connexin 30 deficiency impairs renal tubular ATP release and pressure natriuresis.

    PubMed

    Sipos, Arnold; Vargas, Sarah L; Toma, Ildikó; Hanner, Fiona; Willecke, Klaus; Peti-Peterdi, János

    2009-08-01

    In the renal tubule, ATP is an important regulator of salt and water reabsorption, but the mechanism of ATP release is unknown. Several connexin (Cx) isoforms form mechanosensitive, ATP-permeable hemichannels. We localized Cx30 to the nonjunctional apical membrane of cells in the distal nephron and tested whether Cx30 participates in physiologically important release of ATP. We dissected, partially split open, and microperfused cortical collecting ducts from wild-type and Cx30-deficient mice in vitro. We used PC12 cells as ATP biosensors by loading them with Fluo-4/Fura Red to measure cytosolic calcium and positioning them in direct contact with the apical surface of either intercalated or principal cells. ATP biosensor responses, triggered by increased tubular flow or by bath hypotonicity, were approximately three-fold greater when positioned next to intercalated cells than next to principal cells. In addition, these responses did not occur in preparations from Cx30-deficient mice or with purinergic receptor blockade. After inducing step increases in mean arterial pressure by ligating the distal aorta followed by the mesenteric and celiac arteries, urine output increased 4.2-fold in wild-type mice compared with 2.6-fold in Cx30-deficient mice, and urinary Na(+) excretion increased 5.2-fold in wild-type mice compared with 2.8-fold in Cx30-deficient mice. Furthermore, Cx30-deficient mice developed endothelial sodium channel-dependent, salt-sensitive elevations in mean arterial pressure. Taken together, we suggest that mechanosensitive Cx30 hemichannels have an integral role in pressure natriuresis by releasing ATP into the tubular fluid, which inhibits salt and water reabsorption.

  16. Connexin 30 Deficiency Impairs Renal Tubular ATP Release and Pressure Natriuresis

    PubMed Central

    Sipos, Arnold; Vargas, Sarah L.; Toma, Ildikó; Hanner, Fiona; Willecke, Klaus

    2009-01-01

    In the renal tubule, ATP is an important regulator of salt and water reabsorption, but the mechanism of ATP release is unknown. Several connexin (Cx) isoforms form mechanosensitive, ATP-permeable hemichannels. We localized Cx30 to the nonjunctional apical membrane of cells in the distal nephron and tested whether Cx30 participates in physiologically important release of ATP. We dissected, partially split open, and microperfused cortical collecting ducts from wild-type and Cx30-deficient mice in vitro. We used PC12 cells as ATP biosensors by loading them with Fluo-4/Fura Red to measure cytosolic calcium and positioning them in direct contact with the apical surface of either intercalated or principal cells. ATP biosensor responses, triggered by increased tubular flow or by bath hypotonicity, were approximately three-fold greater when positioned next to intercalated cells than next to principal cells. In addition, these responses did not occur in preparations from Cx30-deficient mice or with purinergic receptor blockade. After inducing step increases in mean arterial pressure by ligating the distal aorta followed by the mesenteric and celiac arteries, urine output increased 4.2-fold in wild-type mice compared with 2.6-fold in Cx30-deficient mice, and urinary Na+ excretion increased 5.2-fold in wild-type mice compared with 2.8-fold in Cx30-deficient mice. Furthermore, Cx30-deficient mice developed endothelial sodium channel–dependent, salt-sensitive elevations in mean arterial pressure. Taken together, we suggest that mechanosensitive Cx30 hemichannels have an integral role in pressure natriuresis by releasing ATP into the tubular fluid, which inhibits salt and water reabsorption. PMID:19478095

  17. Augmenter of liver regeneration inhibits TGF-β1-induced renal tubular epithelial-to-mesenchymal transition via suppressing TβR II expression in vitro

    SciTech Connect

    Liao, Xiao-hui; Zhang, Ling; Chen, Guo-tao; Yan, Ru-yu; Sun, Hang; Guo, Hui; Liu, Qi

    2014-10-01

    Tubular epithelial-to-mesenchymal transition (EMT) plays a crucial role in the progression of renal tubular interstitial fibrosis (TIF), which subsequently leads to chronic kidney disease (CKD) and eventually, end-stage renal disease (ESRD). We propose that augmenter of liver regeneration (ALR), a member of the newly discovered ALR/Erv1 protein family shown to ameliorate hepatic fibrosis, plays a similar protective role in renal tubular cells and has potential as a new treatment option for CKD. Here, we showed that recombinant human ALR (rhALR) inhibits EMT in renal tubular cells by antagonizing activation of the transforming growth factor-β1 (TGF-β1) signaling pathway. Further investigation revealed that rhALR suppresses the expression of TGF-β receptor type II (TβR II) and significantly alleviates TGF-β1-induced phosphorylation of Smad2 and nuclear factor-κB (NF-κB). No apparent adverse effects were observed upon the addition of rhALR alone to cells. These findings collectively suggest that ALR plays a role in inhibiting progression of renal tubular EMT, supporting its potential utility as an effective antifibrotic strategy to reverse TIF in CKD. - Highlights: • ALR is involved in the pathological progression of renal EMT in NRK-52E cells. • ALR suppresses the expression of TβRII and the phosphorylation of Smad2 and NF-κB. • ALR plays a role in inhibiting progression of renal tubular EMT.

  18. Mitochondrial dysfunction contributes to the cytotoxicity induced by tentacle extract from the jellyfish Cyanea capillata in rat renal tubular epithelial NRK-52E cells.

    PubMed

    Wang, Tao; He, Qian; Xiao, Liang; Wang, Qianqian; Zhang, Bo; Wang, Beilei; Liu, Guoyan; Zheng, Jiemin; Yu, Bentong; Zhang, Liming

    2013-11-01

    Our previous studies have shown that tentacle extract (TE) from the jellyfish Cyanea capillata could induce a delayed jellyfish envenomation syndrome with severe multiple organ dysfunctions, among which renal injury with tubular necrosis seemed to be most serious. So, in this study, we aimed to explore the toxic effect of TE on rat renal tubular epithelial NRK-52E cells. Based on the previous findings that TE could cause oxidative damage in erythrocytes, the effects of TE on cell oxidative stress conditions, including ROS production and lipid peroxidation, and mitochondrial dysfunction associated with cell death were investigated in NRK-52E cells. The results showed that TE caused cell morphological change and decreased cell viability through induction of apoptosis and necrosis in NRK-52E cells. Meanwhile, ROS overproduction and mitochondrial membrane potential decrease were found before the cell death occurred. It was concluded that TE could induce cytotoxicity, especially apoptosis and necrosis, in NRK-52E cells, and mitochondrial dysfunction and ROS overproduction might play important roles in the process of cell injury and death.

  19. GSTA3 Attenuates Renal Interstitial Fibrosis by Inhibiting TGF-Beta-Induced Tubular Epithelial-Mesenchymal Transition and Fibronectin Expression

    PubMed Central

    Xiao, Yun; Liu, Jishi; Peng, Yu; Xiong, Xuan; Huang, Ling; Yang, Huixiang; Zhang, Jian; Tao, Lijian

    2016-01-01

    Tubular epithelial-mesenchymal transition (EMT) has been widely accepted as the underlying mechanisms of renal interstitial fibrosis (RIF). The production of reactive oxygen species (ROS) plays a vital role in tubular EMT process. The purpose of this study was to investigate the involved molecular mechanisms in TGF-beta-induced EMT and identify the potential role of glutathione S-transferase alpha 3 (GSTA3) in this process. The iTRAQ screening was performed to identify protein alterations of the rats underwent unilateral-ureteral obstruction (UUO). Protein expression of GSTA3 in patients with obstructive nephropathy and UUO rats was detected by immunohistochemistry. Protein and mRNA expression of GSTA3 in UUO rats and NRK-52E cells were determined by Western blot and RT-PCR. siRNA and overexpression plasmid were transfected specifically to assess the role of GSTA3 in RIF. The generation of ROS was measured by dichlorofluorescein fluorescence analysis. GSTA3 protein and mRNA expression was significantly reduced in UUO rats. Immunohistochemical analysis revealed that GSTA3 expression was reduced in renal cortex in UUO rats and patients with obstructive nephropathy. Treating with TGF-β1 down-regulated GSTA3 expression in NRK-52E cells, which have been found to be correlated with the decreased expression in E-cadherin and megalin and increased expression in α-smooth muscle actin. Furthermore, knocking down GSTA3 in NRK-52 cells led to increased production of ROS and tubular EMT, whereas overexpressing GSTA3 ameliorated ROS production and prevented the occurrence of tubular EMT. GSTA3 plays a protective role against tubular EMT in renal fibrosis, suggesting GSTA3 is a potential therapeutic target for RIF. PMID:27602565

  20. Hypoxia Induces Mesenchymal Gene Expression in Renal Tubular Epithelial Cells: An in vitro Model of Kidney Transplant Fibrosis.

    PubMed

    Zell, Stephanie; Schmitt, Roland; Witting, Sandra; Kreipe, Hans H; Hussein, Kais; Becker, Jan U

    2013-01-01

    The development of interstitial fibrosis and tubular atrophy is a common complication after kidney transplantation and is associated with reduced long-term outcome. The hallmark of tubulointerstitial fibrosis is an increase in extracellular matrix resulting from exaggerated activation of fibroblasts/myofibroblasts, and tubular atrophy is characterized by a decrease in tubular diameter and loss of function. Atrophic epithelial cells may undergo epithelial-to-mesenchymal transition (EMT) with potential differentiation into interstitial fibroblasts. One potential driver of EMT in developing interstitial fibrosis and tubular atrophy is chronic hypoxia. The expression of 46 EMT-related genes was analyzed in an in vitro hypoxia model in renal proximal tubular epithelial cells (RPTEC). Furthermore, the expression of 342 microRNAs (miR) was evaluated in hypoxic culture conditions. Hypoxic RPTEC expressed markers of a more mesenchymal phenotype and showed an increased expression of matrix metalloproteinase-2 (MMP2). MMP2 expression in RPTEC correlated inversely with a decreased expression of miR-124, which was found to have a putative binding site for the MMP2 transcript. Overexpression of miR-124 inhibited MMP2 protein translation. Hypoxia was associated with increased migration/proliferation of RPTEC which was reversed by miR-124. These results indicate that hypoxia promotes a mesenchymal and migratory phenotype in renal epithelial cells, which is associated with increased MMP2 expression. Hypoxia-dependent MMP2 expression is regulated via a reduced transcription of miR-124. Overexpression of miR-124 antagonizes hypoxia-induced cell migration. Further research is needed to elucidate the functional role of miR-124 and MMP2 in the development of fibrosis in renal transplant degeneration.

  1. Hypoxia Induces Mesenchymal Gene Expression in Renal Tubular Epithelial Cells: An in vitro Model of Kidney Transplant Fibrosis

    PubMed Central

    Zell, Stephanie; Schmitt, Roland; Witting, Sandra; Kreipe, Hans H.; Hussein, Kais; Becker, Jan U.

    2013-01-01

    Background The development of interstitial fibrosis and tubular atrophy is a common complication after kidney transplantation and is associated with reduced long-term outcome. The hallmark of tubulointerstitial fibrosis is an increase in extracellular matrix resulting from exaggerated activation of fibroblasts/myofibroblasts, and tubular atrophy is characterized by a decrease in tubular diameter and loss of function. Atrophic epithelial cells may undergo epithelial-to-mesenchymal transition (EMT) with potential differentiation into interstitial fibroblasts. One potential driver of EMT in developing interstitial fibrosis and tubular atrophy is chronic hypoxia. Methods The expression of 46 EMT-related genes was analyzed in an in vitro hypoxia model in renal proximal tubular epithelial cells (RPTEC). Furthermore, the expression of 342 microRNAs (miR) was evaluated in hypoxic culture conditions. Results Hypoxic RPTEC expressed markers of a more mesenchymal phenotype and showed an increased expression of matrix metalloproteinase-2 (MMP2). MMP2 expression in RPTEC correlated inversely with a decreased expression of miR-124, which was found to have a putative binding site for the MMP2 transcript. Overexpression of miR-124 inhibited MMP2 protein translation. Hypoxia was associated with increased migration/proliferation of RPTEC which was reversed by miR-124. Conclusions These results indicate that hypoxia promotes a mesenchymal and migratory phenotype in renal epithelial cells, which is associated with increased MMP2 expression. Hypoxia-dependent MMP2 expression is regulated via a reduced transcription of miR-124. Overexpression of miR-124 antagonizes hypoxia-induced cell migration. Further research is needed to elucidate the functional role of miR-124 and MMP2 in the development of fibrosis in renal transplant degeneration. PMID:23898346

  2. GSTA3 Attenuates Renal Interstitial Fibrosis by Inhibiting TGF-Beta-Induced Tubular Epithelial-Mesenchymal Transition and Fibronectin Expression.

    PubMed

    Xiao, Yun; Liu, Jishi; Peng, Yu; Xiong, Xuan; Huang, Ling; Yang, Huixiang; Zhang, Jian; Tao, Lijian

    2016-01-01

    Tubular epithelial-mesenchymal transition (EMT) has been widely accepted as the underlying mechanisms of renal interstitial fibrosis (RIF). The production of reactive oxygen species (ROS) plays a vital role in tubular EMT process. The purpose of this study was to investigate the involved molecular mechanisms in TGF-beta-induced EMT and identify the potential role of glutathione S-transferase alpha 3 (GSTA3) in this process. The iTRAQ screening was performed to identify protein alterations of the rats underwent unilateral-ureteral obstruction (UUO). Protein expression of GSTA3 in patients with obstructive nephropathy and UUO rats was detected by immunohistochemistry. Protein and mRNA expression of GSTA3 in UUO rats and NRK-52E cells were determined by Western blot and RT-PCR. siRNA and overexpression plasmid were transfected specifically to assess the role of GSTA3 in RIF. The generation of ROS was measured by dichlorofluorescein fluorescence analysis. GSTA3 protein and mRNA expression was significantly reduced in UUO rats. Immunohistochemical analysis revealed that GSTA3 expression was reduced in renal cortex in UUO rats and patients with obstructive nephropathy. Treating with TGF-β1 down-regulated GSTA3 expression in NRK-52E cells, which have been found to be correlated with the decreased expression in E-cadherin and megalin and increased expression in α-smooth muscle actin. Furthermore, knocking down GSTA3 in NRK-52 cells led to increased production of ROS and tubular EMT, whereas overexpressing GSTA3 ameliorated ROS production and prevented the occurrence of tubular EMT. GSTA3 plays a protective role against tubular EMT in renal fibrosis, suggesting GSTA3 is a potential therapeutic target for RIF.

  3. Significant Accumulation of Polymyxin in Single Renal Tubular Cells: A Medicinal Chemistry and Triple Correlative Microscopy Approach

    PubMed Central

    2016-01-01

    Polymyxin is the last-line therapy against Gram-negative ‘superbugs’; however, dose-limiting nephrotoxicity can occur in up to 60% of patients after intravenous administration. Understanding the accumulation and concentration of polymyxin within renal tubular cells is essential for the development of novel strategies to ameliorate its nephrotoxicity and to develop safer, new polymyxins. We designed and synthesized a novel dual-modality iodine-labeled fluorescent probe for quantitative mapping of polymyxin in kidney proximal tubular cells. Measured by synchrotron X-ray fluorescence microscopy, polymyxin concentrations in single rat (NRK-52E) and human (HK-2) kidney tubular cells were approximately 1930- to 4760-fold higher than extracellular concentrations. Our study is the first to quantitatively measure the significant uptake of polymyxin in renal tubular cells and provides crucial information for the understanding of polymyxin-induced nephrotoxicity. Importantly, our approach represents a significant methodological advancement in determination of drug uptake for single-cell pharmacology. PMID:25553489

  4. Liver transplant in a case of arthrogryposis-renal tubular dysfunction-cholestasis syndrome with severe intractable pruritus.

    PubMed

    Dehghani, Seyed Mohsen; Bahador, Ali; Nikeghbalian, Saman; Salahi, Heshmatollah; Geramizadeh, Bita; Malekpour, Abdorrasoul; Malek-Hosseini, Seyed Ali

    2013-06-01

    Arthrogryposis-renal tubular dysfunction-cholestasis syndrome (MIM No. 208085) is a rare multisystem disorder involving the liver, kidney, skin, and central nervous and musculoskeletal systems. The syndrome is an autosomal-recessive trait, associated with germ-line mutations in the VPS33B gene. We report an Iranian boy of consanguineous cousin parents who had congenital deformities of the upper and lower extremities, severe ichthyosis, cholestasis, intractable pruritus, metabolic acidosis, and failure to thrive. Owing to cholestasis, severe intractable pruritus, and poor quality of life, he underwent a living-related liver transplant from his mother, and his ichthyosis and pruritus dramatically improved. To the best of our knowledge, this is a first case of someone with arthrogryposis-renal tubular dysfunction-cholestasis syndrome who underwent a liver transplant and is in good condition more than 5 years after surgery.

  5. Arg tyrosine kinase modulates TGF-β1 production in human renal tubular cells under high-glucose conditions.

    PubMed

    Torsello, Barbara; Bianchi, Cristina; Meregalli, Chiara; Di Stefano, Vitalba; Invernizzi, Lara; De Marco, Sofia; Bovo, Giorgio; Brivio, Rinaldo; Strada, Guido; Bombelli, Silvia; Perego, Roberto A

    2016-08-01

    Renal tubular cells are involved in the tubular interstitial fibrosis observed in diabetic nephropathy. It is debated whether epithelial-mesenchymal transition (EMT) affects tubular cells, which under high-glucose conditions overproduce transforming growth factor-β (TGF-β), a fibrogenic cytokine involved in interstitial fibrosis development. Our study investigated the involvement of non-receptor tyrosine kinase Arg (also called Abl2) in TGF-β production. Human primary tubular cell cultures exposed to high-glucose conditions were used. These cells showed an elongated morphology, stress fibers and vimentin increment but maintained most of the epithelial marker expression and distribution. In these cells exposed to high glucose, which overexpressed and secreted active TGF-β1, Arg protein and activity was downregulated. A further TGF-β1 increase was induced by Arg silencing with siRNA, as with the Arg tyrosine kinase inhibitor Imatinib. In the cells exposed to high glucose, reactive oxygen species (ROS)-dependent Arg kinase downregulation induced both RhoA activation, through p190RhoGAPA (also known as ARHGAP35) modulation, and proteasome activity inhibition. These data evidence a new specific involvement of Arg kinase into the regulation of TGF-β1 expression in tubular cells under high-glucose conditions and provide cues for new translational approaches in diabetic nephropathy.

  6. Reversal of radiocontrast medium toxicity in human renal proximal tubular cells by white grape juice extract.

    PubMed

    Andreucci, Michele; Faga, Teresa; Pisani, Antonio; Sabbatini, Massimo; Russo, Domenico; Mattivi, Fulvio; De Sarro, Giovambattista; Navarra, Michele; Michael, Ashour

    2015-03-05

    Radiocontrast media (RCM)-induced nephrotoxicity (CIN) is a major clinical problem accounting for 12% of all hospital-acquired cases of acute kidney injury. The pathophysiology of CIN is not well understood, but direct toxic effects on renal cells have been postulated as contributing to CIN. We have investigated the effect of a white grape (Vitis vinifera) juice extract (WGJe) on human renal proximal tubular (HK-2) cells treated with the radiocontrast medium (RCM) sodium diatrizoate. WGJe caused an increase in phosphorylation of the prosurvival kinases Akt and ERK1/2 in HK-2 cells. Treatment of HK-2 cells with 75 mgI/ml sodium diatrizoate for 2.5h and then further incubation (for 27.5h) after removal of the RCM caused a drastic decrease in cell viability. However, pre-treatment with WGJe, prior to incubation with diatrizoate, dramatically improved cell viability. Analysis of key signaling molecules by Western blotting showed that diatrizoate caused a drastic decrease in phosphorylation of Akt (Ser473), FOXO1 (Thr24) and FOXO3a (Thr32) during the initial 2.5h incubation period, and WGJe pre-treatment caused a reversal of these effects. Further analysis by Western blotting of samples from HK-2 cells cultured for longer periods of time (for up to 27.5h after an initial 2.5h exposure to diatrizoate with or without WGJe pre-treatment) showed that WGJe pre-treatment caused a negative effect on phosphorylation of p38, NF-κB (Ser276) and pERK1/2 whilst having a positive effect on the phosphorylation of Akt, FOXO1/FOXO3a and maintained levels of Pim-1 kinase. WGJe may alleviate RCM toxicity through modulation of signaling molecules that are known to be involved in cell death and cell survival and its possible beneficial effects should be further investigated. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Characterization of hyaluronan cable structure and function in renal proximal tubular epithelial cells.

    PubMed

    Selbi, W; de la Motte, C A; Hascall, V C; Day, A J; Bowen, T; Phillips, A O

    2006-10-01

    Alteration in the glycosaminoglycan hyaluronan (HA) has been demonstrated in numerous renal diseases. We have demonstrated that renal proximal tubular epithelial cells (PTCs) surround themselves in vitro with HA in an organized pericellular matrix or 'coat', which is associated with cell migration, and also form pericellular HA cable-like structures which modulate PTC-mononuclear leukocytes interactions. The aim of this study was to characterize potential regulatory mechanism in the assembly of PTC-HA into pericellular cables. HA cables are generated by PTCs in the absence of serum. Immunohistochemical analysis demonstrates the incorporation of components of the inter-alpha-inhibitor (IalphaI) family of proteins and versican into HA cables. Addition of an antibody to IalphaI/PalphaI (pre-alpha-inhibitor) inhibits cable formation. In contrast, inhibition of tumor necrosis factor-alpha-stimulated gene 6 (TSG-6) has no effect on cable formation, suggesting that their generation is independent of the known heavy-chain transfer activity of TSG-6. Overexpression of HAS3 is associated with induction of HA cable formation, and also increased incorporation of HA into pericellular coats. Functionally, this resulted in enhanced HA-dependent monocyte binding and cell migration, respectively. Cell surface expression of CD44 and trypsin-released cell-associated HA were increased in HAS3-overexpressing cells. In addition, hyaluronidase (hyal1 and hyal2) and bikunin mRNA expression were increased, whereas PalphaI HC3 mRNA expression was unchanged in the transfected cells. The data demonstrate the importance of IalphaI/PalphaI in cable formation and suggest that expression of HAS3 may be critical for HA cable assembly.

  8. Renal distal tubular handling of sodium in central fluid volume homoeostasis in preascitic cirrhosis

    PubMed Central

    Sansoe, G; Ferrari, A; Baraldi, E; Castellana, C; De Santis, M C; Manenti, F

    1999-01-01

    BACKGROUND/AIMS—Patients with preascitic liver cirrhosis have an increased central plasma volume, and, for any given plasma aldosterone concentration, they excrete less sodium than healthy controls. A detailed study of the distribution of sodium reabsorption along the segments of the renal tubule, especially the distal one, is still lacking in preascitic cirrhosis.
METHODS—Twelve patients with Child-Pugh class A cirrhosis and nine control subjects (both groups on a normosodic diet) were submitted to the following investigations: (a) plasma levels of active renin and aldosterone; (b) four hour renal clearance of lithium (an index of fluid delivery to the loop of Henle), creatinine, sodium, and potassium; (c) dopaminergic activity, as measured by incremental aldosterone response to intravenous metoclopramide.
RESULTS—Metoclopramide induced higher incremental aldosterone responses, indicating increased dopaminergic activity in patients than controls, which is evidence of an increased central plasma volume (+30 min: 160.2 (68.8) v 83.6 (35.2) pg/ml, p<0.01; +60 min: 140.5 (80.3) v 36.8 (36.1) pg/ml, p<0.01). Patients had increased distal fractional sodium reabsorption compared with controls (26.9 (6.7)% v 12.5 (3.4)% of the filtered sodium load, p<0.05). In the patient group there was an inverse correlation between: (a) absolute distal sodium reabsorption and active renin (r −0.59, p<0.05); (b) fractional distal sodium reabsorption and sodium excretion (r −0.66, p<0.03).
CONCLUSIONS—These data suggest that in preascitic cirrhosis the distal fractional tubular reabsorption of sodium is increased and critical in regulating both central fluid volume and sodium excretion.


Keywords: kidney; sodium handling; lithium clearance; liver cirrhosis; dopamine; central fluid volume PMID:10517915

  9. Bioengineering of living renal membranes consisting of hierarchical, bioactive supramolecular meshes and human tubular cells.

    PubMed

    Dankers, Patricia Y W; Boomker, Jasper M; Huizinga-van der Vlag, Ali; Wisse, Eva; Appel, Wilco P J; Smedts, Frank M M; Harmsen, Martin C; Bosman, Anton W; Meijer, W; van Luyn, Marja J A

    2011-01-01

    Maintenance of polarisation of epithelial cells and preservation of their specialized phenotype are great challenges for bioengineering of epithelial tissues. Mimicking the basement membrane and underlying extracellular matrix (ECM) with respect to its hierarchical fiber-like morphology and display of bioactive signals is prerequisite for optimal epithelial cell function in vitro. We report here on a bottom-up approach based on hydrogen-bonded supramolecular polymers and ECM-peptides to make an electro-spun, bioactive supramolecular mesh which can be applied as synthetic basement membrane. The supramolecular polymers used, self-assembled into nano-meter scale fibers, while at micro-meter scale fibers were formed by electro-spinning. We introduced bioactivity into these nano-fibers by intercalation of different ECM-peptides designed for stable binding. Living kidney membranes were shown to be bioengineered through culture of primary human renal tubular epithelial cells on these bioactive meshes. Even after a long-term culturing period of 19 days, we found that the cells on bioactive membranes formed tight monolayers, while cells on non-active membranes lost their monolayer integrity. Furthermore, the bioactive membranes helped to support and maintain renal epithelial phenotype and function. Thus, incorporation of ECM-peptides into electro-spun meshes via a hierarchical, supramolecular method is a promising approach to engineer bioactive synthetic membranes with an unprecedented structure. This approach may in future be applied to produce living bioactive membranes for a bio-artificial kidney. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Renal tubular acidosis in Sjögren's syndrome: a case series.

    PubMed

    Ram, Rapur; Swarnalatha, Gudithi; Dakshinamurty, Kaligotla Venkata

    2014-01-01

    The exact frequency of distal and proximal renal tubular acidosis (RTA) in Sjögren's syndrome is unknown. Other features of Sjögren's syndrome like polyuria, glomerular manifestations, familial occurrence and pregnancy are not widely reported. The aim was to prospectively study the clinical features and outcome of distal and proximal RTA in Sjögren's syndrome and also report on other renal manifestations of Sjögren's syndrome. The present study is a prospective consecutive case series of patients who presented with a history suggestive of RTA and Sjögren's syndrome. All patients were followed for 1 year. The diagnosis of RTA was by fractional excretion of bicarbonate. The diagnosis of Sjögren's syndrome was according to the American-European classification system [modified by Tzioufas and Voulgarelis: Best Pract Res Clin Rheumatol 2007;21:989-1010]. The total number of RTA patients diagnosed during this period was 149. Sjögren's syndrome accounted for 34.8% (52 of 149) of RTA patients. The important symptoms and laboratory parameters were oral and ocular symptoms in 23 (44.2%), dental caries in 12 (23%), body pains in 47 (90.3%), mean serum pH 7.202 ± 0.03, mean serum bicarbonate, 14.03 ± 1.66 mmol/l, and mean urine pH, 7.125 ± 0.54. There were 30 (57.6%) patients with distal RTA and 22 (42.3%) patients with proximal RTA. The clinical implication of the present study is that RTA is a common feature of Sjögren's syndrome. It may be missed if the presentation is not due to oral and ocular symptoms. The present study is also the only one with a 1-year follow-up. © 2014 S. Karger AG, Basel.

  11. Clinical and biochemical findings in Mexican patients with distal renal tubular acidosis.

    PubMed

    Guerra-Hernández, Norma; Matos-Martínez, Mario; Ordaz-López, Karen Verónica; Camargo-Muñiz, María Dolores; Medeiros, Mara; Escobar-Pérez, Laura

    2014-01-01

    Renal tubular acidosis (RTA) is a rare disease characterized by a normal serum anion gap, sustained metabolic acidosis, low concentration of plasma bicarbonate, variable hyperchloremia and hypokalemia and conserved glomerular filtration rate. RTA is developed during the first year of life and produces failure to thrive and anorexia. Primary distal RTA (type 1) is a renal syndrome with a reduced ability to excrete the acid load through the collecting ducts and impairment to concentrate the urine causing polyuria and dehydration. Evaluate the current health status and describe the clinical findings and progress of Mexican patients with distal RTA. Demonstrate the distal urinary acidification defect by measuring the urinary pCO2 tension in alkaline urines. We looked for infants in tertiary care hospitals with a clinical history of normal serum anion gap, metabolic acidosis, hypokalemia, hyperchloremia, nephrocalcinosis, sensorineural hearing loss and inability for urine acidification under systemic metabolic acidosis. Biochemical analysis were performed periodically. Alkali medication was not suspended in one patient to assess urinary acidification with oral administration of sodium bicarbonate (2 mEq/Kg) and acetazolamide (500 mg/1.73 m2 body surface). Urinary pCO2 levels were determined at 60 and 90 min. Three children, one adolescent and one adult with distal RTA were found. They had an infant history of dehydration, failure to thrive, anorexia, vomiting, muscle paralysis, hypercalciuria, urinary infections, polyuria, polydipsia and polyhidramnios during pregnancy. Severe nephrocalcinosis was detected in all patients whereas sensorineural hearing loss was developed in four cases. Under the alkali medication all cases but one were normocalciuric. A patient developed kidney failure. The urinary acidification test confirmed the innability to eliminate the acid load. Early diagnosis in infancy and continuos alkali medication were of great benefit for most of the

  12. Renal expression of the C3a receptor and functional responses of primary human proximal tubular epithelial cells.

    PubMed

    Braun, Michael C; Reins, Rose Y; Li, Tong-Bin; Hollmann, Travis J; Dutta, Ranjan; Rick, Wetsel A; Teng, Ba-Bie; Ke, Baozhen

    2004-09-15

    Although complement activation and deposition have been associated with a variety of glomerulopathies, the pathogenic mechanisms by which complement directly mediates renal injury remain to be fully elucidated. Renal parenchymal tissues express a limited repertoire of receptors that directly bind activated complement proteins. We report the renal expression of the receptor for the C3 cleavage product C3a, a member of the anaphylatoxin family. C3aR is highly expressed in normal human and murine kidney, as demonstrated by immunohistochemistry and in situ hybridization. Its distribution is limited to epithelial cells only, as glomerular endothelial and mesangial cells showed no evidence of C3aR expression. The C3aR is also expressed by primary renal proximal tubular epithelial cells in vitro as demonstrated by FACS, Western blot, and RT-PCR. In vitro C3aR is functional in terms of its capacity to bind 125I-labeled C3a and generate inositol triphosphate. Finally, using microarray analysis, four novel genes were identified and confirmed as transcriptionally regulated by C3aR activation in proximal tubular cells. These studies define a new pathway by which complement activation may directly modulate the renal response to immunologic injury.

  13. Numb Protects Human Renal Tubular Epithelial Cells From Bovine Serum Albumin-Induced Apoptosis Through Antagonizing CHOP/PERK Pathway.

    PubMed

    Ding, Xuebing; Ma, Mingming; Teng, Junfang; Shao, Fengmin; Wu, Erxi; Wang, Xuejing

    2016-01-01

    In recent studies, we found that Numb is involved in oxidative stress-induced apoptosis of renal proximal tubular cells; however, its function on ER stress-induced apoptosis in proteinuric kidney disease remains unknown. The objective of the present study is to explore the role of Numb in urinary albumin-induced apoptosis of human renal tubular epithelial cells (HKCs). In this study, we demonstrate that incubation of HKCs with bovine serum albumin (BSA) resulted in caspase three-dependent cell death. Numb expression was down-regulated by BSA in a time- and dose-dependent manner. Knockdown of Numb by siRNA sensitized HKCs to BSA-induced apoptosis, whereas overexpression of Numb protected HKCs from BSA-induced apoptosis. Moreover, BSA activated CHOP/PERK signaling pathway in a time- and dose-dependent manner as indicated by increased expression of CHOP, PERK, and P-PERK. Furthermore, knockdown of CHOP or PERK significantly attenuated the promoting effect of Numb on BSA-induced apoptosis, while overexpression of CHOP impaired the protective effect of Numb on BSA-induced apoptosis. Taken together, our findings demonstrate that Numb plays a protective role on BSA-induced apoptosis through inhibiting CHOP/PERK signaling pathway in human renal tubular epithelial cells. Therefore, the results from this study provides evidence that Numb is a new target of ER-associated apoptotic signaling networks and Numb may serve as a promising therapeutic target for proteinuric diseases.

  14. Distal renal tubular acidosis in mice that lack the forkhead transcription factor Foxi1

    PubMed Central

    Blomqvist, Sandra Rodrigo; Vidarsson, Hilmar; Fitzgerald, Sharyn; Johansson, Bengt R.; Ollerstam, Anna; Brown, Russell; Persson, A. Erik G.; Bergström, Göran; Enerbäck, Sven

    2004-01-01

    While macro- and microscopic kidney development appear to proceed normally in mice that lack Foxi1, electron microscopy reveals an altered ultrastructure of cells lining the distal nephron. Northern blot analyses, cRNA in situ hybridizations, and immunohistochemistry demonstrate a complete loss of expression of several anion transporters, proton pumps, and anion exchange proteins expressed by intercalated cells of the collecting ducts, many of which have been implicated in hereditary forms of distal renal tubular acidosis (dRTA). In Foxi1-null mutants the normal epithelium with its two major cell types — principal and intercalated cells — has been replaced by a single cell type positive for both principal and intercalated cell markers. To test the functional consequences of these alterations, Foxi1–/– mice were compared with WT littermates in their response to an acidic load. This revealed an inability to acidify the urine as well as a lowered systemic buffer capacity and overt acidosis in null mutants. Thus, Foxi1–/– mice seem to develop dRTA due to altered cellular composition of the distal nephron epithelium, thereby denying this epithelium the proper gene expression pattern needed for maintaining adequate acid-base homeostasis. PMID:15173882

  15. Ceramide-Induced Apoptosis in Renal Tubular Cells: A Role of Mitochondria and Sphingosine-1-Phoshate

    PubMed Central

    Ueda, Norishi

    2015-01-01

    Ceramide is synthesized upon stimuli, and induces apoptosis in renal tubular cells (RTCs). Sphingosine-1 phosphate (S1P) functions as a survival factor. Thus, the balance of ceramide/S1P determines ceramide-induced apoptosis. Mitochondria play a key role for ceramide-induced apoptosis by altered mitochondrial outer membrane permeability (MOMP). Ceramide enhances oligomerization of pro-apoptotic Bcl-2 family proteins, ceramide channel, and reduces anti-apoptotic Bcl-2 proteins in the MOM. This process alters MOMP, resulting in generation of reactive oxygen species (ROS), cytochrome C release into the cytosol, caspase activation, and apoptosis. Ceramide regulates apoptosis through mitogen-activated protein kinases (MAPKs)-dependent and -independent pathways. Conversely, MAPKs alter ceramide generation by regulating the enzymes involving ceramide metabolism, affecting ceramide-induced apoptosis. Crosstalk between Bcl-2 family proteins, ROS, and many signaling pathways regulates ceramide-induced apoptosis. Growth factors rescue ceramide-induced apoptosis by regulating the enzymes involving ceramide metabolism, S1P, and signaling pathways including MAPKs. This article reviews evidence supporting a role of ceramide for apoptosis and discusses a role of mitochondria, including MOMP, Bcl-2 family proteins, ROS, and signaling pathways, and crosstalk between these factors in the regulation of ceramide-induced apoptosis of RTCs. A balancing role between ceramide and S1P and the strategy for preventing ceramide-induced apoptosis by growth factors are also discussed. PMID:25751724

  16. Novel human renal proximal tubular cell line for the production of complex proteins.

    PubMed

    Fliedl, Lukas; Manhart, Gabriele; Kast, Florian; Katinger, Hermann; Kunert, Renate; Grillari, Johannes; Wieser, Matthias; Grillari-Voglauer, Regina

    2014-04-20

    Human host cell lines for the production of biopharmaceutical proteins are of interest due to differences in the glycosylation patterns of human and animal cell lines. Specifically, sialylation, which has a major impact on half-life and immunogenicity of recombinant biopharmaceuticals, differs markedly. Here, we established and characterized an immortalized well documented and serum-free host cell line, RS, from primary human renal proximal tubular epithelial cells (RPTEC). In order to test its capacity to produce complex glycosylated proteins, stable recombinant human erythropoietin (rhEpo) producing clones were generated. The clone with highest productivity, RS-1C9 was further characterized and showed stable productivity. Biological activity was observed in in vitro assays and 28% of rhEpo glyco-isoforms produced by RS-1C9 were in range and distribution of the biological reference standard (BRP) isoform, as compared to 11.5% of a CHO based rhEpo. Additionally, cellular α-2,6 sialylation, Galactose-alpha-1,3-galactose (alpha-Gal) and N-glycolylneuraminic acid (NeuGc) patterns compare favourably to CHO cells. While productivity of RS still needs optimization, its amenability to upscaling in bioreactors, its production of glyco-isoforms that will increase yields after down-stream processing of about 2.5 fold, presence of sialylation and lack of Neu5Gc recommend RS as alternative human host cell line for production of biopharmaceuticals. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. The effects of colloid solutions on renal proximal tubular cells in vitro.

    PubMed

    Neuhaus, Winfried; Schick, Martin A; Bruno, Raphael R; Schneiker, Bianca; Förster, Carola Y; Roewer, Norbert; Wunder, Christian

    2012-02-01

    Renal failure is a common complication of critically ill patients. Colloids such as hydroxyethyl starch (HES), gelatin, or albumin are regularly used for intravascular volume resuscitation, but there are increasing reports about the nephrotoxic side effects of synthetic colloids in septic patients. Therefore, we investigated the influence of colloids (HES130/0.4 (Voluven®), gelatin (Gelafundin®), human albumin, and the crystalloid Sterofundin® ISO on cell viability of human proximal tubular (HK-2) cells. HK-2 cells were incubated with colloids (0.1%-4%) and with equivalent volumes of the crystalloid solution Sterofundin ISO. After 21 hours, cell viability of HK-2 cells was measured by EZ4U assay (dye XTT). Application of HES130/0.4 decreased cell viability significantly in a concentration-dependent manner (86.80% ± 10.79% by 0.5% HES down to 24.02% ± 4.27% by 4% HES). Human albumin (>1.25%) as well as gelatin (>1%) also showed deleterious effects on HK-2 cells. Interestingly, in lower concentrations, human albumin and the crystalloid solution Sterofundin ISO were cytoprotective in comparison with the NaCl control. In conclusion, synthetic and natural colloids showed a harmful impact on HK-2 cells in higher concentrations without any prior proinflammatory stimulus. HES130/0.4 exhibited the most distinctive harmful impact, whereas the application of crystalloid Sterofundin ISO revealed cytoprotective effects.

  18. The Protective Effect of Glycyrrhizic Acid on Renal Tubular Epithelial Cell Injury Induced by High Glucose

    PubMed Central

    Hou, Shaozhang; Zheng, Fangfang; Li, Yuan; Gao, Ling; Zhang, Jianzhong

    2014-01-01

    The aim of this study was to determine the beneficial effect of glycyrrhizic acid (GA) on type 2 diabetic nephropathy using renal tubular epithelial cell line (NRK-52E). The cells are divided into normal group (NG), high glucose group (HG), and treatment group (HG + GA). The methylthiazoletetrazolium (MTT) assay was used to detect the cell proliferation. Cell cycle analysis was performed using flow cytometry. Model driven architecture (MDA), reactive oxygen species (ROS) and superoxide dismutase (SOD) were also measured. Electron microscopy and histological were used to detect the changes in cell ultrastructure. The phosphorylation of AMP-activated protein kinase (AMPK), silent information regulator T1 (SIRT1), manganese-superoxide dismutase (Mn-SOD) and transforming growth factor-β1 (TGF-β1) were assessed by immunohistochemistry, immunofluorescence, and western blotting. Real-time fluorescent quantitative PCR (RT-qPCR) was used to measure Mn-SOD and PPARγ co-activator 1α (PGC-1a) mRNA. We find that high glucose increases NRK-52E cell proliferation and TGF-β1 expression, but decreases expression of AMPK, SIRT1 and Mn-SOD. These effects are significantly attenuated by GA. Our findings suggest that GA has protective effects against high glucose-induced cell proliferation and oxidative stress at least in part by increasing AMPK, SIRT1 and Mn-SOD expression in NRK-52E cells. PMID:25162824

  19. The protective effect of glycyrrhizic acid on renal tubular epithelial cell injury induced by high glucose.

    PubMed

    Hou, Shaozhang; Zheng, Fangfang; Li, Yuan; Gao, Ling; Zhang, Jianzhong

    2014-08-26

    The aim of this study was to determine the beneficial effect of glycyrrhizic acid (GA) on type 2 diabetic nephropathy using renal tubular epithelial cell line (NRK-52E). The cells are divided into normal group (NG), high glucose group (HG), and treatment group (HG + GA). The methylthiazoletetrazolium (MTT) assay was used to detect the cell proliferation. Cell cycle analysis was performed using flow cytometry. Model driven architecture (MDA), reactive oxygen species (ROS) and superoxide dismutase (SOD) were also measured. Electron microscopy and histological were used to detect the changes in cell ultrastructure. The phosphorylation of AMP-activated protein kinase (AMPK), silent information regulator T1 (SIRT1), manganese-superoxide dismutase (Mn-SOD) and transforming growth factor-β1 (TGF-β1) were assessed by immunohistochemistry, immunofluorescence, and western blotting. Real-time fluorescent quantitative PCR (RT-qPCR) was used to measure Mn-SOD and PPARγ co-activator 1α (PGC-1a) mRNA. We find that high glucose increases NRK-52E cell proliferation and TGF-β1 expression, but decreases expression of AMPK, SIRT1 and Mn-SOD. These effects are significantly attenuated by GA. Our findings suggest that GA has protective effects against high glucose-induced cell proliferation and oxidative stress at least in part by increasing AMPK, SIRT1 and Mn-SOD expression in NRK-52E cells.

  20. Ouabain Contributes to Kidney Damage in a Rat Model of Renal Ischemia-Reperfusion Injury.

    PubMed

    Villa, Luca; Buono, Roberta; Ferrandi, Mara; Molinari, Isabella; Benigni, Fabio; Bettiga, Arianna; Colciago, Giorgia; Ikehata, Masami; Messaggio, Elisabetta; Rastaldi, Maria Pia; Montorsi, Francesco; Salonia, Andrea; Manunta, Paolo

    2016-10-14

    Warm renal ischemia performed during partial nephrectomy has been found to be associated with kidney disease. Since endogenous ouabain (EO) is a neuro-endocrine hormone involved in renal damage, we evaluated the role of EO in renal ischemia-reperfusion injury (IRI). We measured plasma and renal EO variations and markers of glomerular and tubular damage (nephrin, KIM-1, Kidney-Injury-Molecule-1, α1 Na-K ATPase) and the protective effect of the ouabain inhibitor, rostafuroxin. We studied five groups of rats: (1) normal; (2) infused for eight weeks with ouabain (30 µg/kg/day, OHR) or (3) saline; (4) ouabain; or (5) saline-infused rats orally treated with 100 µg/kg/day rostafuroxin for four weeks. In group 1, 2-3 h after IRI, EO increased in ischemic kidneys while decreased in plasma. Nephrin progressively decreased and KIM-1 mRNA increased starting from 24 h. Ouabain infusion (group 2) increased blood pressure (from 111.7 to 153.4 mmHg) and ouabain levels in plasma and kidneys. In OHR ischemic kidneys at 120 h from IRI, nephrin, and KIM-1 changes were greater than those detected in the controls infused with saline (group 3). All these changes were blunted by rostafuroxin treatment (groups 4 and 5). These findings support the role of EO in IRI and suggest that rostafuroxin pre-treatment of patients before partial nephrectomy with warm ischemia may reduce IRI, particularly in those with high EO.

  1. Role of calcitonin gene-related peptide in hypertension-induced renal damage.

    PubMed

    Bowers, Mark C; Katki, Khurshed A; Rao, Arundhati; Koehler, Michael; Patel, Parag; Spiekerman, Alvin; DiPette, Donald J; Supowit, Scott C

    2005-07-01

    Calcitonin gene-related peptide, a potent vasodilator neuropeptide, is localized in perivascular sensory nerves. We have reported that alpha-calcitonin gene-related peptide knockout mice have elevated baseline blood pressure and enhanced hypertension-induced renal damage compared with wild-type controls. Thus, the aim of this study was to determine the mechanism and functional significance of this increased hypertension-induced renal damage. We previously demonstrated by telemetric recording that the deoxycorticosterone-salt protocol produces a 35% increase in mean arterial pressure in both alpha-calcitonin gene-related peptide knockout and wild-type mice. Both strains of mice were studied at 0, 14, and 21 days after deoxycorticosterone-salt hypertension. Renal sections from hypertensive wild-type mice showed no pathological changes at any time point studied. However, on days 14 and 21, hypertensive knockout mice displayed progressive increases in glomerular proliferation, crescent formation, and tubular protein casts, as well as the inflammatory markers intercellular adhesion molecule-1, vascular adhesion molecule-1, and monocyte chemoattractant protein-1. There was a significant increase in 24-hour urinary isoprostane, a marker of oxidative stress-induced lipid peroxidation, levels at days 14 and 21 in the hypertensive knockout compared with hypertensive wild-type mice. Urinary microalbumin was significantly higher (2-fold) at day 21 and creatinine clearance was significantly decreased 4-fold in the hypertensive knockout compared with hypertensive wild-type mice. Therefore, in the absence of alpha-calcitonin gene-related peptide, deoxycorticosterone-salt hypertension induces enhanced oxidative stress, inflammation, and renal histopathologic damage, resulting in reduced renal function. Thus, sensory nerves, via alpha-calcitonin gene-related peptide, appear to be renoprotective against hypertension-induced damage.

  2. Deletion of transient receptor potential vanilloid type 1 receptors exaggerates renal damage in deoxycorticosterone acetate-salt hypertension.

    PubMed

    Wang, Youping; Babánková, Dagmar; Huang, Jie; Swain, Greg M; Wang, Donna H

    2008-08-01

    To determine whether the transient receptor potential vanilloid type 1 (TRPV1) channel provides protection against hypertension-induced renal damage, hypertension was induced by uninephrectomy and by giving deoxycorticosterone acetate (DOCA)-salt in wild-type (WT) and TRPV1-null mutant (TRPV1-/-) mice. Mean arterial pressure, as determined by radiotelemetry, increased significantly and reached the peak 7 days after DOCA-salt treatment in both WT and TRPV1-/- mice. There was no difference in mean arterial pressure between the 2 strains at the baseline or at the peak that lasted for 4 treatment weeks. DOCA-salt treatment in both WT and TRPV1-/- mice led to increased urinary excretion of albumin and 8-isoprostane, glomerulosclerosis, renal cortical tubulointerstitial injury, tubulointerstitial fibrosis, increased number of tubular proliferating cell nuclear antigen-positive cells, and renal monocyte/macrophage infiltration, all of which were much more severe in DOCA-salt-treated TRPV1-/- compared with DOCA-salt-treated WT mice. Renal TRPV1 protein expression, but not the renal anandamide content, was elevated in DOCA-salt-treated WT compared with vehicle-treated WT mice. Renal anandamide levels were markedly elevated in DOCA-salt-treated TRPV1-/- but not in vehicle-treated TRPV1-/- mice. Thus, our data show that ablation of the TRPV1 gene exacerbates renal damage induced by DOCA-salt hypertension, indicating that TRPV1 may constitute a protective mechanism against end-organ damage induced by hypertension.

  3. Lipid droplet accumulation is associated with an increase in hyperglycemia-induced renal damage: prevention by liver X receptors.

    PubMed

    Kiss, Eva; Kränzlin, Bettina; Wagenblaβ, Katja; Bonrouhi, Mahnaz; Thiery, Joachim; Gröne, Elisabeth; Nordström, Viola; Teupser, Daniel; Gretz, Norbert; Malle, Ernst; Gröne, Hermann-Josef

    2013-03-01

    Dyslipidemia is a frequent component of the metabolic disorder of diabetic patients contributing to organ damage. Herein, in low-density lipoprotein receptor-deficient hyperlipidemic and streptozotozin-induced diabetic mice, hyperglycemia and hyperlipidemia acted reciprocally, accentuating renal injury and altering renal function. In hyperglycemic-hyperlipidemic kidneys, the accumulation of Tip47-positive lipid droplets in glomeruli, tubular epithelia, and macrophages was accompanied by the concomitant presence of the oxidative stress markers xanthine oxidoreductase and nitrotyrosine, findings that could also be evidenced in renal biopsy samples of diabetic patients. As liver X receptors (LXRα,β) regulate genes linked to lipid and carbohydrate homeostasis and inhibit inflammatory gene expression in macrophages, the effects of systemic and macrophage-specific LXR activation were analyzed on renal damage in hyperlipidemic-hyperglycemic mice. LXR stimulation by GW3965 up-regulated genes involved in cholesterol efflux and down-regulated proinflammatory/profibrotic cytokines, inhibiting the pathomorphology of diabetic nephropathy, renal lipid accumulation, and improving renal function. Xanthine oxidoreductase and nitrotyrosine levels were reduced. In macrophages, GW3965 or LXRα overexpression significantly suppressed glycated or acetylated low-density lipoprotein-induced cytokines and reactive oxygen species. Specifically, in mice, transgenic expression of LXRα in macrophages significantly ameliorated hyperlipidemic-hyperglycemic nephropathy. The results demonstrate the presence of lipid droplet-induced oxidative mechanisms and the pathophysiologic role of macrophages in diabetic kidneys and indicate the potent regulatory role of LXRs in preventing renal damage in diabetes.

  4. Glomerular lipidosis accompanied by renal tubular oxalosis in wild and laboratory-reared Japanese rock ptarmigans (Lagopus mutus japonicus).

    PubMed

    Murai, Atsuko; Murakami, Mami; Sakai, Hiroki; Shimizu, Hiroaki; Murata, Koichi; Yanai, Tokuma

    2011-12-01

    Glomerular lipidosis is a disease characterized by lipid accumulation in mesangial cells but that has not been fully investigated in avian species. We examined four wild and two laboratory-reared Japanese rock ptarmigans (Lagopus mutus japonicus)--an endangered avian species--presenting vacuolar deposits in the glomeruli. All cases had vacuolar deposits in the glomeruli. In the wild cases, fewer than 30% of all glomeruli were affected, compared with more than 90% in the laboratory-reared cases. In the wild cases, most deposits were mild and restricted to the mesangial areas of glomeruli. In the laboratory-reared cases, nearly all of the deposits covered entire glomeruli. Electron microscopy of mild deposits revealed vacuoles in the cytoplasm of mesangial cells. These vacuoles were positive for Sudan III, Sudan black B, oil red O, Nile blue, periodic acid-Schiff, Schultz test, and digitonin stain and were negative for performaric acid-Schiff stains. Based on these results, we diagnosed the glomerular lesion as glomerular lipidosis caused by uptake of low-density lipoprotein in mesangial cells. Except for one wild case, all cases exhibited renal tubular oxalosis. The severity of tubular oxalosis tended to be related to the severity of glomerular lipidosis: In cases of mild glomerular lipidosis, tubular oxalosis was also mild or absent. We therefore diagnosed the primary lesion as glomerular lipidosis accompanied by tubular oxalosis. The four wild cases came from different zones and therefore had no opportunities to interbreed and no common relatives. We believe these data support the hypothesis that glomerular lipidosis is a disease of the general population ofJapanese rock ptarmigans. This is the first report of glomerular lipidosis accompanied by renal tubular oxalosis in an avian species.

  5. A Beverage Containing Fermented Black Soybean Ameliorates Ferric Nitrilotriacetate-Induced Renal Oxidative Damage in Rats

    PubMed Central

    Okazaki, Yasumasa; Iqbal, Mohammad; Kawakami, Norito; Yamamoto, Yorihiro; Toyokuni, Shinya; Okada, Shigeru

    2010-01-01

    It is beneficial to seek scientific basis for the effects of functional foods. Natural pigments derived from plants are widely known as possible antioxidants. Black soybean contains a larger amount of anthocyanins than regular soybean. Here we studied the antioxidative effect of a beverage obtained via citric acid fermentation of black soybean (BBS), using a rat model of renal oxidative injury induced by a renal carcinogen, ferric nitrilotriacetate. BBS (10 ml/kg) was orally administered 30 min before ferric nitrilotriacetate treatment. Renal lipid peroxidation was significantly suppressed in the BBS-pretreated animals concomitant with decrease in 4-hydroxy-2-nonenal-modified proteins and 8-hydroxy-2'-deoxyguanosine. Maintenance of renal activities of antioxidative enzymes including catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, glucose-6-phosphate dehydrogenase and quinone reductase was significantly better in the BBS-pretreated rats. Elevation of serum creatinine and urea nitrogen was significantly suppressed in the BBS-pretreated rats. These data suggest that dietary intake of BBS is useful for the prevention of renal tubular oxidative damage mediate by iron, and warrant further investigation. PMID:21103028

  6. Changes of thioredoxin, oxidative stress markers, inflammation and muscle/renal damage following intensive endurance exercise.

    PubMed

    Sugama, Kaoru; Suzuki, Katsuhiko; Yoshitani, Kayo; Shiraishi, Koso; Miura, Shigeki; Yoshioka, Hiroshi; Mori, Yuichi; Kometani, Takashi

    2015-01-01

    Thioredoxin (TRX) is a 12 kDa protein that is induced by oxidative stress, scavenges reactive oxygen species (ROS) and modulates chemotaxis. Furthermore it is thought to play a protective role in renal ischemia/reperfusion injury. Complement 5a (C5a) is a chemotactic factor of neutrophils and is produced after ischemia/reperfusion injury in the kidney. Both TRX and C5a increase after endurance exercise. Therefore, it may be possible that TRX has an association with C5a in renal disorders and/or renal protection caused by endurance exercise. Accordingly, the aim of this study was to investigate relationships among the changes of urine levels of TRX, C5a and acute kidney injury (AKI) caused by ischemia/reperfusion, inflammatory responses, and oxidative stress following intensive endurance exercise. Also, we applied a newly-developed measurement system of neutrophil migratory activity and ROS-production by use of ex vivo hydrogel methodology with an extracellular matrix to investigate the mechanisms of muscle damage. Fourteen male triathletes participated in a duathlon race consisting of 5 km of running, 40 km of cycling and 5 km of running were recruited to the study. Venous blood and urine samples were collected before, immediately following, 1.5 h and 3 h after the race. Plasma, serum and urine were analyzed using enzyme-linked immunosorbent assays, a free radical analytical system, and the ex vivo neutrophil functional measurement system. These data were analyzed by assigning participants to damaged and minor-damage groups by the presence and absence of renal tubular epithelial cells in the urinary sediments. We found strong associations among urinary TRX, C5a, interleukin (IL)-2, IL-4, IL-8, IL-10, interferon (IFN)-γ and monocyte chemotactic protein (MCP)-1. From the data it might be inferred that urinary TRX, MCP-1 and β-N-acetyl-D-glucosaminidase (NAG) were associated with renal tubular injury. Furthermore, TRX may be influenced by levels of IL-10, regulate

  7. Renal tubular angiotensin converting enzyme is responsible for nitro-L-arginine methyl ester (L-NAME)-induced salt sensitivity.

    PubMed

    Giani, Jorge F; Eriguchi, Masahiro; Bernstein, Ellen A; Katsumata, Makoto; Shen, Xiao Z; Li, Liang; McDonough, Alicia A; Fuchs, Sebastien; Bernstein, Kenneth E; Gonzalez-Villalobos, Romer A

    2017-04-01

    Renal parenchymal injury predisposes to salt-sensitive hypertension, but how this occurs is not known. Here we tested whether renal tubular angiotensin converting enzyme (ACE), the main site of kidney ACE expression, is central to the development of salt sensitivity in this setting. Two mouse models were used: it-ACE mice in which ACE expression is selectively eliminated from renal tubular epithelial cells; and ACE 3/9 mice, a compound heterozygous mouse model that makes ACE only in renal tubular epithelium from the ACE 9 allele, and in liver hepatocytes from the ACE 3 allele. Salt sensitivity was induced using a post L-NAME salt challenge. While both wild-type and ACE 3/9 mice developed arterial hypertension following three weeks of high salt administration, it-ACE mice remained normotensive with low levels of renal angiotensin II. These mice displayed increased sodium excretion, lower sodium accumulation, and an exaggerated reduction in distal sodium transporters. Thus, in mice with renal injury induced by L-NAME pretreatment, renal tubular epithelial ACE, and not ACE expression by renal endothelium, lung, brain, or plasma, is essential for renal angiotensin II accumulation and salt-sensitive hypertension.

  8. Renal Artery Vasodilation May Be An Indicator of Successful Sympathetic Nerve Damage During Renal Denervation Procedure

    PubMed Central

    Chen, Weijie; Du, Huaan; Lu, Jiayi; Ling, Zhiyu; Long, Yi; Xu, Yanping; Xiao, Peilin; Gyawali, Laxman; Woo, Kamsang; Yin, Yuehui; Zrenner, Bernhard

    2016-01-01

    Autonomic nervous system plays a crucial role in maintaining and regulating vessel tension. Renal denervation (RDN) may induce renal artery vasodilation by damaging renal sympathetic fibers. We conducted this animal study to evaluate whether renal artery vasodilation could be a direct indicator of successful RDN. Twenty-eight Chinese Kunming dogs were randomly assigned into three groups and underwent RDN utilizing temperature-controlled catheter (group A, n = 11) or saline-irrigated catheter (group B, n = 11) or sham procedure (group C, n = 6). Renal angiography, blood pressure (BP) and renal artery vasodilation measurements were performed at baseline, 30-minute, 1-month, and 3-month after interventions. Plasma norepinephrine concentrations were tested at baseline and 3-month after intervention. Results showed that, in addition to significant BP reduction, RDN induced significant renal artery vasodilation. Correlation analyses showed that the induced renal artery vasodilation positively correlated with SBP reduction and plasma norepinephrine reduction over 3 months after ablation. Post hoc analyses showed that saline-irrigated catheter was superior to TC catheter in renal artery vasodilation, especially for the acute dilatation of renal artery at 30-minute after RDN. In conclusion, renal artery vasodilation, induced by RDN, may be a possible indicator of successful renal nerve damage and a predictor of blood pressure response to RDN. PMID:27849014

  9. Antifibrotic effects of KS370G, a caffeamide derivative, in renal ischemia-reperfusion injured mice and renal tubular epithelial cells

    PubMed Central

    Chuang, Sung-Ting; Kuo, Yueh-Hsiung; Su, Ming-Jai

    2014-01-01

    Accumulating evidence suggests that renal tubulointerstitial fibrosis is a main cause of end-stage renal disease. Clinically, there are no beneficial treatments that can effectively reverse the progressive loss of renal functions. Caffeic acid phenethyl ester is a natural phenolic antifibrotic agent, but rapid decomposition by an esterase leads to its low bioavailability. In this study, we evaluated the effects of KS370G, a caffeic acid phenylethyl amide, on murine renal fibrosis induced by unilateral renal ischemia-reperfusion injury (IRI) and in TGF-β1 stimulated renal tubular epithelial cells (NRK52E and HK-2). In the animal model, renal fibrosis was evaluated at 14 days post-operation. Immediately following the operation, KS370G (10 mg/kg) was administered by oral gavage once a day. Our results show that KS370G markedly attenuates collagen deposition and inhibits an IRI-induced increase of fibronectin, vimentin, α-SMA and TGF-β1 expression and plasma TGF-β1 levels in the mouse kidney. Furthermore, KS370G reverses TGF-β1-induced downregulation of E-cadherin and upregulation of α-SMA and also decreases the expression of fibronectin, collagen I and PAI-1 and inhibits TGF-β1-induced phosphorylation of Smad2/3. These findings show the beneficial effects of KS370G on renal fibrosis in vivo and in vitro with the possible mechanism being the inhibition of the Smad2/3 signaling pathway. PMID:25056456

  10. A case surviving for over a year of renal tubular dysgenesis with compound heterozygous angiotensinogen gene mutations.

    PubMed

    Uematsu, Mitsugu; Sakamoto, Osamu; Nishio, Toshiyuki; Ohura, Toshihiro; Matsuda, Tadashi; Inagaki, Tetsuji; Abe, Takaaki; Okamura, Kunihiro; Kondo, Yoshiaki; Tsuchiya, Shigeru

    2006-11-01

    Renal tubular dysgenesis (RTD) is a developmental abnormality of the renal proximal tubules found in patients with Potter syndrome. We report a female newborn with RTD who has survived for more than 18 months. Infusions of fresh frozen plasma (FFP) in the early neonatal period were effective in raising and maintaining her blood pressure. Peritoneal dialysis was required until the appearance of spontaneous urination at 29 days after birth. Histopathological examinations of the kidney revealed dilated renal tubular lumina and foamy columnar epithelial cells in the renal tubules. Endocrinological studies showed a discrepancy between low plasma renin activity (<0.1 ng/ml/hr) and high active renin concentration (135,000 pg/ml), suggesting an aberration in the renin substrate, angiotensinogen. Direct sequencing analysis revealed two novel mutations in the coding region of the angiotensinogen gene (AGT): a nonsense mutation in exon 2 (c.604C > T) and a frameshift deletion at nucleotide 1290 in exon 5 (c.1290delT). The mutations were in the compound heterozygous state, because each parent had each mutation. These findings suggest that angiotensinogen deficiency is one of the causes of RTD. A treatment of the condition with FFP may help to promote long survival.

  11. Sirt1 protects against oxidative stress-induced renal tubular cell apoptosis by the bidirectional regulation of catalase expression

    SciTech Connect

    Hasegawa, Kazuhiro; Wakino, Shu Yoshioka, Kyoko; Tatematsu, Satoru; Hara, Yoshikazu; Minakuchi, Hitoshi; Washida, Naoki; Tokuyama, Hirobumi; Hayashi, Koichi; Itoh, Hiroshi

    2008-07-18

    NAD{sup +}-dependent protein deacetylase Sirt1 regulates cellular apoptosis. We examined the role of Sirt1 in renal tubular cell apoptosis by using HK-2 cells, proximal tubular cell lines with or without reactive oxygen species (ROS), H{sub 2}O{sub 2}. Without any ROS, Sirt1 inhibitors enhanced apoptosis and the expression of ROS scavenger, catalase, and Sirt1 overexpression downregulated catalase. When apoptosis was induced with H{sub 2}O{sub 2}, Sirt1 was upregulated with the concomitant increase in catalase expression. Sirt1 overexpression rescued H{sub 2}O{sub 2}-induced apoptosis through the upregulation of catalase. H{sub 2}O{sub 2} induced the nuclear accumulation of forkhead transcription factor, FoxO3a and the gene silencing of FoxO3a enhanced H{sub 2}O{sub 2}-induced apoptosis. In conclusion, endogenous Sirt1 maintains cell survival by regulating catalase expression and by preventing the depletion of ROS required for cell survival. In contrast, excess ROS upregulates Sirt1, which activates FoxO3a and catalase leading to rescuing apoptosis. Thus, Sirt1 constitutes a determinant of renal tubular cell apoptosis by regulating cellular ROS levels.

  12. Leptin reduces gentamicin-induced apoptosis in rat renal tubular cells via the PI3K-Akt signaling pathway.

    PubMed

    Chen, Yen-Cheng; Chen, Cheng-Hsien; Hsu, Yung-Ho; Chen, Tso-Hsiao; Sue, Yuh-Mou; Cheng, Chung-Yi; Chen, Tzen-Wen

    2011-05-11

    Leptin, a circulating hormone secreted mainly from adipose tissues, possesses protective effects on many cell types. Serum leptin concentration increases in patients with chronic renal failure and those undergoing maintenance dialysis. Gentamicin, a widely used antibiotic for the treatment of bacterial infection, can cause nephrotoxicity. In the present study, we intended to investigate the influence of leptin on apoptotic pathways and its mechanism in rat renal tubular cells treated with gentamicin. By using Annexin V-FITC/propidium iodide double staining, we found that leptin expressed a dose-dependent protective effect against gentamicin-induced apoptosis in rat renal tubular cells (NRK-52E) within 24h. Pretreatment of the cells with 50 or 100 ng/ml of leptin induced Bcl-2 and Bcl-x(L), increased the phosphorylation of Bad, and decreased the cleaved caspase-3 and caspase-9 in gentamicin-treated NRK-52E cells. Leptin also suppressed the activation of the transcription factor NF-κB and upregulated Akt activation in gentamicin-treated NRK-52E cells. We found that leptin activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway as demonstrated by the suppression of the anti-apoptotic effect of leptin by wortmannin. The treatment of wortmannin suppressed the leptin-induced phospho-Akt, Bcl-2, phospho-Bad as well as Bcl-x(L), and recovered the leptin-reduced cleaved caspase-3 and caspase-9. Based on our results, we suggested that leptin can attenuate gentamicin-induced apoptotic injury in rat renal tubular cells through PI3K/Akt signaling pathway.

  13. Hypercalcaemia of malignancy: evidence for a nonparathyroid humoral agent with an effect on renal tubular handling of calcium.

    PubMed

    Ralston, S H; Fogelman, I; Gardner, M D; Dryburgh, F J; Cowan, R A; Boyle, I T

    1984-02-01

    The renal handling of calcium was examined in 31 patients with hypercalcaemia of malignancy. Results were compared with those from patients with primary hyperparathyroidism, and normal controls rendered hypercalcaemic by calcium infusion. On relating the urinary calcium excretion indices to serum calcium values, inappropriately low rates of urinary calcium excretion were generally found in patients with malignancy associated hypercalcaemia. Further, the pattern of urinary calcium excretion in these subjects was similar to that found in patients with primary hyperparathyroidism. These observations suggest that, in many solid tumours, the development of hypercalcaemia may be attributable to a humoral mediator with a parathyroid hormone-like effect on renal tubular calcium reabsorption. The relatively frequent occurrence of hypercalcaemia in malignant disease thus may be partially explained by the presence of this humoral agent, which may impair the renal excretion of an increase in filtered calcium load, whether due to bone metastases, or humorally mediated osteolysis.

  14. Renal tubular NHE3 is required in the maintenance of water and sodium chloride homeostasis.

    PubMed

    Fenton, Robert A; Poulsen, Søren B; de la Mora Chavez, Samantha; Soleimani, Manoocher; Dominguez Rieg, Jessica A; Rieg, Timo

    2017-04-03

    The sodium/proton exchanger isoform 3 (NHE3) is expressed in the intestine and the kidney, where it facilitates sodium (re)absorption and proton secretion. The importance of NHE3 in the kidney for sodium chloride homeostasis, relative to the intestine, is unknown. Constitutive tubule-specific NHE3 knockout mice (NHE3(loxloxCre)) did not show significant differences compared to control mice in body weight, blood pH or bicarbonate and plasma sodium, potassium, or aldosterone levels. Fluid intake, urinary flow rate, urinary sodium/creatinine, and pH were significantly elevated in NHE3(loxloxCre) mice, while urine osmolality and GFR were significantly lower. Water deprivation revealed a small urinary concentrating defect in NHE3(loxloxCre) mice on a control diet, exaggerated on low sodium chloride. Ten days of low or high sodium chloride diet did not affect plasma sodium in control mice; however, NHE3(loxloxCre) mice were susceptible to low sodium chloride (about -4 mM) or high sodium chloride intake (about +2 mM) versus baseline, effects without differences in plasma aldosterone between groups. Blood pressure was significantly lower in NHE3(loxloxCre) mice and was sodium chloride sensitive. In control mice, the expression of the sodium/phosphate co-transporter Npt2c was sodium chloride sensitive. However, lack of tubular NHE3 blunted Npt2c expression. Alterations in the abundances of sodium/chloride cotransporter and its phosphorylation at threonine 58 as well as the abundances of the α-subunit of the epithelial sodium channel, and its cleaved form, were also apparent in NHE3(loxloxCre) mice. Thus, renal NHE3 is required to maintain blood pressure and steady-state plasma sodium levels when dietary sodium chloride intake is modified.

  15. Molecular investigation of distal renal tubular acidosis in Tunisia, evidence for founder mutations.

    PubMed

    Nagara, Majdi; Voskarides, Konstantinos; Nouira, Sonia; Ben Halim, Nizar; Kefi, Rym; Aloulou, Hajer; Romdhane, Lilia; Ben Abdallah, Rim; Ben Rhouma, Faten; Aissa, Khaoula; Boughamoura, Lamia; Kammoun, Thouraya; Azzouz, Hatem; Abroug, Saoussen; Ben Turkia, Hathemi; Ayadi, Abdelkarim; Mrad, Ridha; Chabchoub, Imen; Hachicha, Mongia; Chemli, Jalel; Deltas, Constantinos; Abdelhak, Sonia

    2014-11-01

    Distal renal tubular acidosis (dRTA) is a rare genetic disease caused by mutations in different genes involved in the secretion of H+ ions in the intercalated cells of the collecting duct. Both autosomal dominant and recessive forms have been described; the latter is also associated with sensorineural hearing loss. Twenty-two Tunisian families were analyzed for mutations in the ATP6V1B1 and ATP6V0A4 genes by direct sequencing. Dating of the founder mutations was performed. Two founder mutations in the ATP6V1B1 gene were found in 16/27 dRTA cases. The p.Ile386Hisfs*56 founder mutation was estimated to be older than 2400 years and no correlations were found with deafness. For the remaining patients, two mutations in the ATP6V0A4 gene, one of them being novel, were found in three Tunisian cases. The presence of a heterozygous missense mutation p.T30I, of the ATP6V1B1 gene, was identified in six patients, while no mutations of the second gene were detected. No deleterious mutations of either ATP6V1B1 or ATP6V0A were found for the two probands. Our study gives evidence of phenotypic and genotypic heterogeneity of dRTA in the Tunisian population. Five different mutations were found, two of them were due to a founder effect, and screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA.

  16. Missense mutation T485S alters NBCe1-A electrogenicity causing proximal renal tubular acidosis.

    PubMed

    Zhu, Quansheng; Shao, Xuesi M; Kao, Liyo; Azimov, Rustam; Weinstein, Alan M; Newman, Debra; Liu, Weixin; Kurtz, Ira

    2013-08-15

    Mutations in SLC4A4, the gene encoding the electrogenic Na(+)-HCO3(-) cotransporter NBCe1, cause severe proximal renal tubular acidosis (pRTA), growth retardation, decreased IQ, and eye and teeth abnormalities. Among the known NBCe1 mutations, the disease-causing mechanism of the T485S (NBCe1-A numbering) mutation is intriguing because the substituted amino acid, serine, is structurally and chemically similar to threonine. In this study, we performed intracellular pH and whole cell patch-clamp measurements to investigate the base transport and electrogenic properties of NBCe1-A-T485S in mammalian HEK 293 cells. Our results demonstrated that Ser substitution of Thr485 decreased base transport by ~50%, and importantly, converted NBCe1-A from an electrogenic to an electroneutral transporter. Aqueous accessibility analysis using sulfhydryl reactive reagents indicated that Thr485 likely resides in an NBCe1-A ion interaction site. This critical location is also supported by the finding that G486R (a pRTA causing mutation) alters the position of Thr485 in NBCe1-A thereby impairing its transport function. By using NO3(-) as a surrogate ion for CO3(2-), our result indicated that NBCe1-A mediates electrogenic Na(+)-CO3(2-) cotransport when functioning with a 1:2 charge transport stoichiometry. In contrast, electroneutral NBCe1-T485S is unable to transport NO3(-), compatible with the hypothesis that it mediates Na(+)-HCO3(-) cotransport. In patients, NBCe1-A-T485S is predicted to transport Na(+)-HCO3(-) in the reverse direction from blood into proximal tubule cells thereby impairing transepithelial HCO3(-) absorption, possibly representing a new pathogenic mechanism for generating human pRTA.

  17. Molecular Investigation of Distal Renal Tubular Acidosis in Tunisia, Evidence for Founder Mutations

    PubMed Central

    Voskarides, Konstantinos; Nouira, Sonia; Ben Halim, Nizar; Kefi, Rym; Aloulou, Hajer; Romdhane, Lilia; Ben Abdallah, Rim; Ben Rhouma, Faten; Aissa, Khaoula; Boughamoura, Lamia; Kammoun, Thouraya; Azzouz, Hatem; Abroug, Saoussen; Ben Turkia, Hathemi; Ayadi, Abdelkarim; Mrad, Ridha; Chabchoub, Imen; Hachicha, Mongia; Chemli, Jalel; Deltas, Constantinos; Abdelhak, Sonia

    2014-01-01

    Background: Distal renal tubular acidosis (dRTA) is a rare genetic disease caused by mutations in different genes involved in the secretion of H+ ions in the intercalated cells of the collecting duct. Both autosomal dominant and recessive forms have been described; the latter is also associated with sensorineural hearing loss. Methods: Twenty-two Tunisian families were analyzed for mutations in the ATP6V1B1 and ATP6V0A4 genes by direct sequencing. Dating of the founder mutations was performed. Results: Two founder mutations in the ATP6V1B1 gene were found in 16/27 dRTA cases. The p.Ile386Hisfs*56 founder mutation was estimated to be older than 2400 years and no correlations were found with deafness. For the remaining patients, two mutations in the ATP6V0A4 gene, one of them being novel, were found in three Tunisian cases. The presence of a heterozygous missense mutation p.T30I, of the ATP6V1B1 gene, was identified in six patients, while no mutations of the second gene were detected. No deleterious mutations of either ATP6V1B1 or ATP6V0A were found for the two probands. Conclusion: Our study gives evidence of phenotypic and genotypic heterogeneity of dRTA in the Tunisian population. Five different mutations were found, two of them were due to a founder effect, and screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA. PMID:25285676

  18. The influence of dietary potassium on the renal tubular effect of hydrochlorothiazide in the rat.

    PubMed Central

    Shirley, D. G.; Skinner, J.; Walter, S. J.

    1987-01-01

    The influence of dietary potassium on the natriuretic effect of hydrochlorothiazide was investigated in conscious rats which had access to 0.46 M NaCl solution; the intake of saline was used as an index of the natriuresis. Control rats drank very little saline (less than 1 mmol 24 h-1), whereas animals given hydrochlorothiazide in the food (35 mg kg-1 dry weight) increased their saline intake to approximately 10 mmol 24 h-1. In a third group of rats, on a high-potassium diet (360 mmol kg-1 dry weight vs 60 mmol kg-1 dry weight), the same dose of hydrochlorothiazide increased the saline intake to only 2 mmol 24 h-1. In order to investigate the renal mechanisms involved in these effects, animals were anaesthetized and prepared for micropuncture. Collections were made from late surface convolutions of proximal tubules and from early and late regions of distal tubules. Total glomerular filtration rate, single-nephron filtration rate, and the delivery of sodium to the end of the proximal tubule and to the beginning of the distal tubule were similar in the three groups of rats. In rats on a normal diet, hydrochlorothiazide treatment was associated with an increased delivery of sodium to the end of the distal tubule. No such increase was seen in thiazide-treated rats on a high potassium intake. It is concluded that a high potassium intake reduces the natriuretic effect of hydrochlorothiazide as a result of interference with thiazide-induced inhibition of sodium reabsorption in the distal tubule. The effect of potassium does not depend on changes in sodium handling in other nephron segments. The possible roles of aldosterone and distal tubular potassium secretion in mediating this effect are discussed. PMID:3607372

  19. Macrophage-stimulating protein attenuates gentamicin-induced inflammation and apoptosis in human renal proximal tubular epithelial cells

    SciTech Connect

    Lee, Ko Eun; Kim, Eun Young; Kim, Chang Seong; Choi, Joon Seok; Bae, Eun Hui; Ma, Seong Kwon; Kim, Kyung Keun; Lee, Jong Un; Kim, Soo Wan

    2013-05-10

    Highlights: •MSP/RON system is activated in rat kidney damaged by gentamicin. •MSP inhibits GM-induced cellular apoptosis and inflammation in HK-2 cells. •MSP attenuates GM-induced activation of MAPKs and NF-κB pathways in HK-2 cells. -- Abstract: The present study aimed to investigate whether macrophage-stimulating protein (MSP) treatment attenuates renal apoptosis and inflammation in gentamicin (GM)-induced tubule injury and its underlying molecular mechanisms. To examine changes in MSP and its receptor, recepteur d’origine nantais (RON) in GM-induced nephropathy, rats were injected with GM for 7 days. Human renal proximal tubular epithelial (HK-2) cells were incubated with GM for 24 h in the presence of different concentrations of MSP and cell viability was measured by MTT assay. Apoptosis was determined by flow cytometry of cells stained with fluorescein isothiocyanate-conjugated annexin V protein and propidium iodide. Expression of Bcl-2, Bax, caspase-3, cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB), IκB-α, and mitogen-activated protein kinases (MAPKs) was analyzed by semiquantitative immunoblotting. MSP and RON expression was significantly greater in GM-treated rats, than in untreated controls. GM-treatment reduced HK-2 cell viability, an effect that was counteracted by MSP. Flow cytometry and DAPI staining revealed GM-induced apoptosis was prevented by MSP. GM reduced expression of anti-apoptotic protein Bcl-2 and induced expression of Bax and cleaved caspase 3; these effects and GM-induced expression of COX-2 and iNOS were also attenuated by MSP. GM caused MSP-reversible induction of phospho-ERK, phospho-JNK, and phospho-p38. GM induced NF-κB activation and degradation of IκB-α; the increase in nuclear NF-κB was blocked by inhibitors of ERK, JNK, p-38, or MSP pretreatment. These findings suggest that MSP attenuates GM-induced inflammation and apoptosis by inhibition of the MAPKs

  20. Calcitriol Directly Sensitizes Renal Tubular Cells to ATP-Depletion- and Iron-Mediated Attack

    PubMed Central

    Zager, Richard A.

    1999-01-01

    Vitamin Ds have been reported to have diverse effects on cell homeostasis, leading to suggestions that they have therapeutic applications extending beyond their traditional actions on the Ca2+/parathyroid/bone axis. As some of these potential indications carry an inherent risk of acute renal failure (ARF; eg, cancer chemotherapy and organ transplantation), the goal of this study was to assess whether vitamin Ds directly affect renal tubule injury responses. Cultured human proximal tubular (HK-2) cells were exposed to physiological or pharmacological doses of either calcitriol (D3) or a synthetic vitamin D2 analogue (19-nor) for 3 to 48 hours. Their impact on cell integrity (percent lactate dehydrogenase (LDH) release and tetrazolium dye MTT uptake) under basal conditions and during superimposed injuries (ATP depletion/Ca2+ ionophore or iron-mediated oxidant stress) were determined. As vitamin Ds can be anti-proliferative, cell outgrowth ([3H]thymidine uptake and crystal violet staining) was also tested. Finally, the action of D3 on in vivo ARF (glycerol-induced myoglobinuria) and isolated proximal tubule injury responses were assessed. D3 induced a rapid, dose-dependent increase in HK-2 susceptibility to both ATP-depletion/Ca2+-ionophore- and Fe-mediated attack without independently affecting cell integrity or proliferative responses. In contrast, D2 negatively affected only Fe toxicity and only after relatively prolonged exposure (48 hours). D3 dramatically potentiated in vivo ARF (two- to threefold increase in azotemia), suggesting potential in vivo relevance of the above HK-2 cell results. Proximal tubules, isolated from these glycerol-exposed mice, suggested that D3 can worsen tubule injury despite a parodoxic suppression of H2O2 production. In contrast, D3 had a mild negative impact on cellular energetics (depressed ATP/ADP ratios), and it accentuated plasma membrane phospholipid breakdown. The latter was observed in both glycerol-treated and control tubules

  1. THE FAILURE OF CHLOROFORM ADMINISTERED IN THE DRINKING WATER TO INDUCE RENAL TUBULAR CELL NEOPLASIA IN MALE F344/N RATS

    EPA Science Inventory

    The failure of chloroform administered in drinking water to induce renal tubular cell neoplasia in male F344/N rats

    Chloroform (TCM) has been demonstrated to be a renal carcinogen in the male Osborne-
    Mendel rat when administered either by corn oil gavage or in drin...

  2. THE FAILURE OF CHLOROFORM ADMINISTERED IN THE DRINKING WATER TO INDUCE RENAL TUBULAR CELL NEOPLASIA IN MALE F344/N RATS

    EPA Science Inventory

    The failure of chloroform administered in drinking water to induce renal tubular cell neoplasia in male F344/N rats

    Chloroform (TCM) has been demonstrated to be a renal carcinogen in the male Osborne-
    Mendel rat when administered either by corn oil gavage or in drin...

  3. Effect of felodipine on renal haemodynamics and tubular sodium handling after single-dose cyclosporin infusion in renal transplant recipients treated with azathioprine and prednisolone.

    PubMed

    Madsen, J K; Kornerup, H J; Pedersen, E B

    1995-11-01

    A total of 25 renal transplant recipients, treated solely with prednisolone and azathioprine, were investigated in a randomized, double-blind, placebo-controlled, cross-over study. The effect of a single oral dose of felodipine 5 mg or placebo on: glomerular filtration rate (GFR); renal plasma flow (RPF); renal vascular resistance (RVR); renal tubular sodium and water handling, measured by the lithium clearance technique; plasma levels of angiotensin II (AngII), aldosterone (Aldo), atrial natriuretic factor (ANF) and arginine vasopressin (AVP); blood pressure (BP), and heart rate (HR) was studied before, during, and after an intravenous infusion of cyclosporin (CyA). Three consecutive clearance periods were performed, each lasting 1 h. During the second period, CyA (0.75 mg kg-1 body weight) was infused. Before infusion of CyA, felodipine caused a significant rise (6.7%) in RPF and lowered RVR, but did not change GFR significantly. The rise in RPF was abolished by infusion of CyA. After infusion, both GFR (7.8%) and RPF (9.4%) were significantly higher and RVR lower after felodipine than after placebo. Proximal tubular output and total sodium excretion were higher on the felodipine day before and after, but not during CyA infusion. In all three periods felodipine reduced both systolic and diastolic BP. In conclusion, a single dose of felodipine increases RPF and decreases blood pressure in renal transplant recipients not treated with CyA. Although some of these changes are abolished by an acute intravenous infusion of CyA, the effects of felodipine are present again also during the 1st hour after the infusion and thereby indicate at least in part some renal protective effect of felodipine. It is suggested that a higher dose of felodipine might also have been preventive against CyA renal side-effects during the acute infusion.

  4. MicroRNA-328 inhibits renal tubular cell epithelial-to-mesenchymal transition by targeting the CD44 in pressure-induced renal fibrosis.

    PubMed

    Chen, Cheng-Hsien; Cheng, Chung-Yi; Chen, Yen-Cheng; Sue, Yuh-Mou; Liu, Chung-Te; Cheng, Tzu-Hurng; Hsu, Yung-Ho; Chen, Tso-Hsiao

    2014-01-01

    Epithelial-mesenchymal transition (EMT) occurs in stressed tubular epithelial cells, contributing to renal fibrosis. Initial mechanisms promoting EMT are unknown. Pressure force is an important mechanism contributing to the induction and progression of renal fibrogenesis in ureteric obstruction. In our study of cultured rat renal tubular cells (NRK-52E) under 60 mmHg of pressure, we found that the epithelial marker E-cadherin decreased and mesenchymal markers, e.g., α-smooth muscle actin, fibronectin and Snail, increased. Pressure also induced the expression of connective tissue growth factor and transforming growth factor-β. MicroRNA array assays showed that pressure reduced miR-328 at the initial stage of pressurization. We identified a potential target sequence of miR-328 in rat CD44 3'-untranslated regions. In contrast with the miR-328 expression, CD44 expression was up-regulated at the initial pressurization stage. We also found that miR-328 expression decreased and CD44 increased in ureteric obstruction kidneys in the animal study. CD44 siRNA transfection significantly increased E-cadherin expression and inhibited pressure-induced EMT. Both hyaluronan binding peptide pep-1 and osteopontin neutralizing antibody inhibited pressure-induced EMT. Our results suggest that miR-328-mediated CD44 transient upregulation is an important trigger of the pressure-induced EMT in renal fibrosis.

  5. Increased Klk9 Urinary Excretion Is Associated to Hypertension-Induced Cardiovascular Damage and Renal Alterations

    PubMed Central

    Blázquez-Medela, Ana M.; García-Sánchez, Omar; Quirós, Yaremi; Blanco-Gozalo, Victor; Prieto-García, Laura; Sancho-Martínez, Sandra M.; Romero, Miguel; Duarte, Juan M.; López-Hernández, Francisco J.; López-Novoa, José M.; Martínez-Salgado, Carlos

    2015-01-01

    Abstract Early detection of hypertensive end-organ damage and secondary diseases are key determinants of cardiovascular prognosis in patients suffering from arterial hypertension. Presently, there are no biomarkers for the detection of hypertensive target organ damage, most outstandingly including blood vessels, the heart, and the kidneys. We aimed to validate the usefulness of the urinary excretion of the serine protease kallikrein-related peptidase 9 (KLK9) as a biomarker of hypertension-induced target organ damage. Urinary, plasma, and renal tissue levels of KLK9 were measured by the Western blot in different rat models of hypertension, including angiotensin-II infusion, DOCA-salt, L-NAME administration, and spontaneous hypertension. Urinary levels were associated to cardiovascular and renal injury, assessed by histopathology. The origin of urinary KLK9 was investigated through in situ renal perfusion experiments. The urinary excretion of KLK9 is increased in different experimental models of hypertension in rats. The ACE inhibitor trandolapril significantly reduced arterial pressure and the urinary level of KLK9. Hypertension did not increase kidney, heart, liver, lung, or plasma KLK9 levels. Hypertension-induced increased urinary excretion of KLK9 results from specific alterations in its tubular reabsorption, even in the absence of overt nephropathy. KLK9 urinary excretion strongly correlates with cardiac hypertrophy and aortic wall thickening. KLK9 appears in the urine in the presence of hypertension as a result of subtle renal handling alterations. Urinary KLK9 might be potentially used as an indicator of hypertensive cardiac and vascular damage. PMID:26469898

  6. Urinary excretion of furosemide in rats with HgCl sub 2 -induced acute renal damage

    SciTech Connect

    Fujimura, Akio; Sudoh, Toshiaki; Ohashi, Kyoichi; Ebihara, Akio )

    1992-01-01

    To examine the influence of mercuric chloride (HgCl{sub 2})-induced acute renal damage on urinary excretion of furosemide, HgCl{sub 2} or its vehicle along was given intraperitoneally to Wistar rats. The following two experiments were done. Study 1: three percent body weight (b.w.) of 1% NaCl solution or furosemide in 3% b.w. of 1% NaCl solution was given orally before and after HgCl{sub 2} treatment, and an 8-hour urine was collected. Study 2: furosemide was given orally, and blood samples were obtained at 1, 2, 3, 4, 6 and 8 hours after administration. Urinary excretion of N-acetyl-{beta}-D-glucosaminidase increased, and urine volume and urinary excretions of furosemide and sodium decreased in the HgCl{sub 2}-treated rats. There were significant correlations between the urinary furosemide and its diuretic effects. Regression lines after HgCl{sub 2} were significantly different from those before treatment. The values of absorption as well as elimination rate constant were smaller, while the time to maximum concentration and the elimination half-life were longer in the HgCl{sub 2}-treated rats compared to vehicle-treated animals. These results suggest that the urinary excretion of furosemide and the responsiveness of renal tubular cells to this agent are impaired in rats with HgCl{sub 2}-induced acute renal damage.

  7. Deletion of the Chloride Transporter Slc26a7 Causes Distal Renal Tubular Acidosis and Impairs Gastric Acid Secretion*

    PubMed Central

    Xu, Jie; Song, Penghong; Nakamura, Suguru; Miller, Marian; Barone, Sharon; Alper, Seth L.; Riederer, Brigitte; Bonhagen, Janina; Arend, Lois J.; Amlal, Hassane; Seidler, Ursula; Soleimani, Manoocher

    2009-01-01

    SLC26A7 (human)/Slc26a7 (mouse) is a recently identified chloride-base exchanger and/or chloride transporter that is expressed on the basolateral membrane of acid-secreting cells in the renal outer medullary collecting duct (OMCD) and in gastric parietal cells. Here, we show that mice with genetic deletion of Slc26a7 expression develop distal renal tubular acidosis, as manifested by metabolic acidosis and alkaline urine pH. In the kidney, basolateral Cl−/HCO3− exchange activity in acid-secreting intercalated cells in the OMCD was significantly decreased in hypertonic medium (a normal milieu for the medulla) but was reduced only mildly in isotonic medium. Changing from a hypertonic to isotonic medium (relative hypotonicity) decreased the membrane abundance of Slc26a7 in kidney cells in vivo and in vitro. In the stomach, stimulated acid secretion was significantly impaired in isolated gastric mucosa and in the intact organ. We propose that SLC26A7 dysfunction should be investigated as a potential cause of unexplained distal renal tubular acidosis or decreased gastric acid secretion in humans. PMID:19723628

  8. Expression and Function of Interleukin-1β-Induced Neutrophil Gelatinase-Associated Lipocalin in Renal Tubular Cells

    PubMed Central

    Mamiya, Ryo; Tsuchiya, Hisashi; Kitanaka, Taku; Namba, Shinichi; Kitanaka, Nanako; Okabayashi, Ken; Narita, Takanori; Sugiya, Hiroshi

    2016-01-01

    Acute kidney injury (AKI) is characterized by a sudden loss of renal function. Early recognition of AKI, especially in critically ill patients, is essential for adequate therapy. Currently, neutrophil gelatinase-associated lipocalin (NGAL) is considered to be an effective biomarker of AKI; however, the regulation of its expression and function in renal tubular cells remains unclear. In this study, we investigated the regulation of the expression and function of NGAL in IL-1β-treated Madin–Darby canine kidney (MDCK) cells as a model of renal tubular cells. IL-1β induced a disturbance in the localization of E-cadherin and zonaoccludin-1 (ZO-1). The transepithelial electrical resistance (TER) also decreased 5 days after IL-1β treatment. IL-1β induced NGAL mRNA expression and protein secretion in a time- and dose-dependent manner, which occurred faster than the decrease in TER. In the presence of ERK1/2 and p38 inhibitors, IL-1β-induced NGAL mRNA expression and protein secretion were significantly attenuated. In the presence of recombinant NGAL, IL-1β-induced disturbance in the localization of E-cadherin and ZO-1 was attenuated, and the decrease in TER was partially maintained. These results suggest that NGAL can be used as a biomarker for AKI and that it functions as a protector from AKI. PMID:27851800

  9. Sinomenine protects mice against ischemia reperfusion induced renal injury by attenuating inflammatory response and tubular cell apoptosis

    PubMed Central

    Zhao, Zhiqing; Guan, Rui; Song, Shaohua; Zhang, Mingjian; Liu, Fang; Guo, Meng; Guo, Wenyuan; Yu, Qilin; Zhang, Luding; Wang, Quanxing

    2013-01-01

    Sinomenine (SIN) is a purified alkaloid from the Chinese herb Sinomenium acutum. Previous studies demonstrated that SIN possesses anti-inflammatory and anti-apoptotic properties. We thus in the present report conducted studies to examine its impact on ischemia reperfusion (IR) induced renal injury. Precondition of mice with 200 mg/kg of SIN provided significant protection for mice against IR-induced renal injury as manifested by the attenuated serum creatinine (Cre) and blood urea nitrogen (BUN) along with less severity for histological changes and tubular cell apoptosis. In line with these results, treatment of mice with SIN suppressed IR-induced inflammatory infiltration and the expression of chemokine CXCL-10, adhesion molecule ICAM-1, and cytokines TNF-а/IL-6. Mechanistic studies revealed that SIN inhibits NF-κB transcriptional activity to suppress IR-induced inflammatory response in the kidney, while it attenuates MAP kinase signaling to prevent tubular cells undergoing apoptosis after IR insult. Altogether, our data support that SIN could be a useful therapeutic agent for prevention and treatment of IR-induced renal injury in the clinical settings. PMID:24040435

  10. Sinomenine protects mice against ischemia reperfusion induced renal injury by attenuating inflammatory response and tubular cell apoptosis.

    PubMed

    Zhao, Zhiqing; Guan, Rui; Song, Shaohua; Zhang, Mingjian; Liu, Fang; Guo, Meng; Guo, Wenyuan; Yu, Qilin; Zhang, Luding; Wang, Quanxing

    2013-01-01

    Sinomenine (SIN) is a purified alkaloid from the Chinese herb Sinomenium acutum. Previous studies demonstrated that SIN possesses anti-inflammatory and anti-apoptotic properties. We thus in the present report conducted studies to examine its impact on ischemia reperfusion (IR) induced renal injury. Precondition of mice with 200 mg/kg of SIN provided significant protection for mice against IR-induced renal injury as manifested by the attenuated serum creatinine (Cre) and blood urea nitrogen (BUN) along with less severity for histological changes and tubular cell apoptosis. In line with these results, treatment of mice with SIN suppressed IR-induced inflammatory infiltration and the expression of chemokine CXCL-10, adhesion molecule ICAM-1, and cytokines TNF-а/IL-6. Mechanistic studies revealed that SIN inhibits NF-κB transcriptional activity to suppress IR-induced inflammatory response in the kidney, while it attenuates MAP kinase signaling to prevent tubular cells undergoing apoptosis after IR insult. Altogether, our data support that SIN could be a useful therapeutic agent for prevention and treatment of IR-induced renal injury in the clinical settings.

  11. Randomized controlled trial: lisinopril reduces proteinuria, ammonia, and renal polypeptide tubular catabolism in patients with chronic allograft nephropathy.

    PubMed

    Amara, Alieu B; Sharma, Asheesh; Alexander, John L; Alfirevic, Ana; Mohiuddin, Atif; Pirmohamed, Munir; Close, Graeme L; Grime, Steve; Maltby, Paul; Shawki, Howida; Heyworth, Sally; Shenkin, Alan; Smith, Linda; Sharma, Ajay K; Hammad, Abdel; Rustom, Rana

    2010-01-15

    Angiotensin-converting enzyme inhibitors in native nephropathies reduce proteinuria and delay progression to renal failure. Data in renal transplantation remain limited. A negative effect on glomerular filtration rate was concluded in a recent systematic review. In this novel randomized controlled trial, 47 patients with chronic allograft nephropathy, severe renal impairment, and more than or equal to 1 g/24 hr proteinuria were randomized to lisinopril (group A) or other hypotensives (group B) for 1 year. Sodium bicarbonate was given to all patients to treat metabolic acidosis prophylactically (acidosis increases significantly with lisinopril). The annual rate of decline of graft function was measured isotopically (primary outcome) and 24 hr proteinuria, genotyping, radiolabeled polypeptide aprotinin proximal tubular catabolic studies (in group A only) as secondary outcome measurements were undertaken. At baseline, groups were comparable except for greater proteinuria in group A. After 1 year, the rate of decline of graft function and graft survival were comparable in both groups. Proteinuria decreased significantly in group A patients only. Lisinopril also significantly reduced radiolabeled aprotinin uptake and metabolism, plasma aldosterone, and ammonia excretion. Plasma potassium, bicarbonate, and mean arterial pressures were comparable in both groups. Patients with more than or equal to 30% reduction in proteinuria had a significant association with rs699 polymorphism in the angiotensinogen gene. The rate of decline of renal graft function in patients with chronic allograft nephropathy was not adversely affected by lisinopril therapy given for 1 year. Lisinopril significantly reduced proteinuria, renal proximal tubular polypeptide catabolism, plasma aldosterone, and ammonia excretion suggesting relative preservation of graft function. Treating metabolic acidosis allowed safe and prolonged use of angiotensinogen-converting enzyme inhibitors.

  12. Long-term leptin treatment exerts a pro-apoptotic effect on renal tubular cells via prostaglandin E2 augmentation.

    PubMed

    Hsu, Yung-Ho; Cheng, Chung-Yi; Chen, Yen-Cheng; Chen, Tso-Hsiao; Sue, Yuh-Mou; Tsai, Wei-Lun; Chen, Cheng-Hsien

    2012-08-15

    Adipokine leptin reportedly acts on the kidney in pathophysiological states. However, the influence of leptin on renal tubular epithelial cells is still unclear. Gentamicin, a widely used antibiotic for the treatment of bacterial infection, can cause nephrotoxicity. This study aims to investigate the influence of long-term leptin treatment on gentamicin-induced apoptosis in rat renal tubular cells (NRK-52E) and mice. We monitored apoptosis and molecular mechanisms using annexin V/ propidium iodide staining and small interfering RNA transfection. In NRK-52E cells, leptin reduced gentamicin-induced apoptosis at 24h, but significantly increased apoptosis at 48 h. Long-term treatment of leptin decreased Bcl-x(L) expression and increased caspase activity in gentamicin-treated NRK-52E cells. Leptin also increased the expression of cyclooxygenase-2 (COX-2) and its product, prostaglandin E(2) (PGE(2)), in a dose-dependent manner. The COX-2 inhibitor, NS398 (N-[2-(Cyclohexyloxy)-4- nitrophenyl]methanesulfonamide), blocked PGE(2) augmentation and the pro-apoptotic effects of leptin. The addition of PGE(2) recovered the pro-apoptotic effect of leptin in NS398-treated NRK-52E cells. In a mouse animal model, a 10 day leptin treatment significantly increased gentamicin-induced apoptotic cells in proximal tubules. NS398 treatment inhibited this in vivo pro-apoptotic effect of leptin. Results reveal that long-term elevation of leptin induces COX-2-mediated PGE(2) augmentation in renal tubular cells, and then increases these cells' susceptibility to gentamicin-induced apoptosis.

  13. Renal tubular secretion of tanshinol: molecular mechanisms, impact on its systemic exposure, and propensity for dose-related nephrotoxicity and for renal herb-drug interactions.

    PubMed

    Jia, Weiwei; Du, Feifei; Liu, Xinwei; Jiang, Rongrong; Xu, Fang; Yang, Junling; Li, Li; Wang, Fengqing; Olaleye, Olajide E; Dong, Jiajia; Li, Chuan

    2015-05-01

    Tanshinol has desirable antianginal and pharmacokinetic properties and is a key compound of Salvia miltiorrhiza roots (Danshen). It is extensively cleared by renal excretion. This study was designed to elucidate the mechanism underlying renal tubular secretion of tanshinol and to compare different ways to manipulate systemic exposure to the compound. Cellular uptake of tanshinol was mediated by human organic anion transporter 1 (OAT1) (Km, 121 μM), OAT2 (859 μM), OAT3 (1888 μM), and OAT4 (1880 μM) and rat Oat1 (117 µM), Oat2 (1207 μM), and Oat3 (1498 μM). Other renal transporters (human organic anion-transporting polypeptide 4C1 [OATP4C1], organic cation transporter 2 [OCT2], carnitine/organic cation transporter 1 [OCTN1], multidrug and toxin extrusion protein 1 [MATE1], MATE2-K, multidrug resistance-associated protein 2 [MRP2], MRP4, and breast cancer resistance protein [BCRP], and rat Oct1, Oct2, Octn1, Octn2, Mate1, Mrp2, Mrp4, and Bcrp) showed either ambiguous ability to transport tanshinol or no transport activity. Rats may be a useful model, to investigate the contribution of the renal transporters on the systemic and renal exposure to tanshinol. Probenecid-induced impairment of tubular secretion resulted in a 3- to 5-fold increase in the rat plasma area under the plasma concentration-time curve from 0 to infinity (AUC0-∞) of tanshinol. Tanshinol exhibited linear plasma pharmacokinetic properties over a large intravenous dose range (2-200 mg/kg) in rats. The dosage adjustment could result in increases in the plasma AUC0-∞ of tanshinol of about 100-fold. Tanshinol exhibited very little dose-related nephrotoxicity. In summary, renal tubular secretion of tanshinol consists of uptake from blood, primarily by OAT1/Oat1, and the subsequent luminal efflux into urine mainly by passive diffusion. Dosage adjustment appears to be an efficient and safe way to manipulate systemic exposure to tanshinol. Tanshinol shows low propensity to cause renal transporter

  14. Increased curvature of hollow fiber membranes could up-regulate differential functions of renal tubular cell layers.

    PubMed

    Shen, Chong; Meng, Qin; Zhang, Guoliang

    2013-08-01

    Tissue engineering devices as in vitro cell culture systems in scaffolds has encountered the bottleneck due to their much lower cell functions than real tissues/organs in vivo. Such situation has been improved in some extent by mimicking the cell microenvironments in vivo from either chemical or physical ways. However, microenvironmental curvature, commonly seen in real tissues/organs, has never been manipulated to regulate the cell performance in vitro. In this regard, this paper fabricated polysulfone membranes with or without polyethylene glycol modification to investigate the impact of curvature on two renal tubular cells. Regardless the varying membrane curvatures among hollow fiber membranes of different diameters and flat membrane of zero curvature, both renal cells could well attach at 4 h of seeding and form similar confluent layers at 6 days on each membrane. Nevertheless, the renal cells on hollow fibers, though showing confluent morphology as those on flat membranes, expressed higher renal functions and, moreover, the renal functions significantly increased with the membrane curvature among hollow fibers. Such upregulation on functions was unassociated with mass transport barrier of hollow fibers, because the cultures on lengthwise cut hollow fibers without mass transfer barrier showed same curvature effect on renal functions as whole hollow fibers. It could be proposed that the curvature of hollow fiber membrane approaching to the large curvature in kidney tubules increased the mechanical stress in the renal cells and thus might up-regulate the renal cell functions. In conclusion, the increase of substrate curvature could up-regulate the cell functions without altering the confluent cell morphology and this finding will facilitate the design of functional tissue engineering devices.

  15. Renal tubular dysfunction presenting as recurrent hypokalemic periodic quadriparesis in systemic lupus erythematosus

    PubMed Central

    Prasad, D.; Agarwal, D.; Malhotra, V.; Beniwal, P.

    2014-01-01

    We report recurrent hypokalemic periodic quadriparesis in a 30-year-old woman. Patient had also symptoms of multiple large and small joint pain, recurrent oral ulceration, photosensitivity and hair loss that were persisting since last 6 months and investigations revealed systemic lupus erythematosus (SLE) with distal tubular acidosis. Our patient was successfully treated with oral potassium chloride, sodium bicarbonate, hydroxychloroquine and a short course of steroids. Thus, tubular dysfunction should be carefully assessed in patients with SLE. PMID:25249723

  16. Target renal damage: the microvascular associations of increased aortic stiffness in patients with COPD

    PubMed Central

    2013-01-01

    Background Although renal impairment has been described in COPD, there is opportunity to evaluate further to determine nature and consider optimal management. Increased aortic stiffness, as seen in COPD, leads to reduced buffering of pulsatile flow. We hypothesised that urinary albumin creatinine ratio (UACR) would reflect glomerular damage related to aortic stiffness. Methods Patients with COPD and controls underwent spirometry, blood pressure, arterial stiffness - aortic pulse wave velocity (PWV) and provided a spot urine sample for UACR, with other renal biomarkers measured. Results The UACR was increased in patients (n = 52): 0.80 mg/mmol compared to controls (n = 34): 0.46 mg/mmol, p < 0.05. Aortic PWV was related to log10 UACR in all subjects (r = 0.426, p < 0.001) and COPD patients alone. Aortic PWV was a significant variable for UACR with oxygen saturations, after accounting for potential confounders. Eight subjects (7 patients) reached a defined clinical microalbuminuria threshold, with aortic PWV greater in these patients compared to those patients without, although albuminuria is a continuum. Proximal tubular damage biomarkers, unlike the glomerular marker, were not different between patients and controls. Conclusions There is glomerular damage in patients with COPD evidenced by increased UACR, related to increased aortic stiffness. Besides the macrovascular prognostic implications of increased aortic stiffness, the microvascular state in COPD management should be considered. PMID:23497267

  17. Role of TNF-associated cytokines in renal tubular cell apoptosis induced by hyperoxaluria.

    PubMed

    Horuz, Rahim; Göktaş, Cemal; Çetinel, Cihangir A; Akça, Oktay; Aydın, Hasan; Ekici, Işın D; Albayrak, Selami; Sarıca, Kemal

    2013-06-01

    Crystal-cell interaction has been reported as one of the most crucial steps in urinary stone formation. Hyperoxaluria-induced apoptotic changes in renal tubular epithelial cells is the end-stage of this interaction. We aimed to evaluate the possible pathways responsible in the induction of apoptosis within the involved cells by assessing the receptoral expression of three different pathways. 16 male Spraque-Dowley rats were divided into two groups: Group 1 (n:8) received only distilled water; Group 2 (n:8) received 0.75 % ethylene glycol (EG) in their daily water to induce hyperoxaluria for 2 weeks. After 24 h urine collection, all animals were euthenized and right kidneys were removed and fixed for immunohistochemical evaluation. Oxalate and creatinine levels (in 24 h-urine) and FAS, tumor necrosis factor (TNF), TNF-related apoptosis-inducing ligand (TRAIL) and TRAIL receptor-2 expressions (in tissue) have been assessed. In addition to TNF (p = 0.0007) expression; both FAS (p = 0.0129 ) and FASL (p = 0.032) expressions significantly increased in animals treated with EG. The expressions of TRAIL (p = 0.49) and TRAIL-R2 (p = 0.34) receptors did not change statistically after hyperoxaluria induction. Although a positive correlation with cytokine expression density and 24 h-urinary oxalate expression (mg oxalate/mg creatinine) has been assessed with TNF (p = 0.04, r = 0.82), FAS (p = 0.05, r = 0.80), FAS-L (p = 0.04, r = 0.82); no correlation could be demonstrated between TRAIL and TRAIL R2 expressions. Our results indicate that apoptosis induced by oxalate is possibly mediated via TNF and FAS pathways. However, TRAIL and TRAIL-R2 seemed to have no function in the cascade. Correlation with urinary oxalate levels did further strengthen the findings.

  18. Cadmium induces phosphorylation and stabilization of c-Fos in HK-2 renal proximal tubular cells

    SciTech Connect

    Iwatsuki, Mamiko; Inageda, Kiyoshi; Matsuoka, Masato

    2011-03-15

    We examined the effects of cadmium chloride (CdCl{sub 2}) exposure on the expression and phosphorylation status of members of the Fos family, components of the activator protein-1 transcription factor, in HK-2 human renal proximal tubular cells. Following the exposure to CdCl{sub 2}, the expression of c-fos, fosB, fra-1, and fra-2 increased markedly, with different magnitudes and time courses. The levels of Fos family proteins (c-Fos, FosB, Fra-1, and Fra-2) also increased in response to CdCl{sub 2} exposure. Although the elevation of c-fos transcripts was transient, c-Fos protein levels increased progressively with lower electrophoretic mobility, suggesting stabilization of c-Fos through post-translational modifications. Consistently, we observed phosphorylation of c-Fos at Ser362 and Ser374 in HK-2 cells treated with CdCl{sub 2}. Phosphorylated forms of mitogen-activated protein kinases (MAPKs)-including extracellular signal-regulated protein kinase (ERK), c-Jun NH{sub 2}-terminal kinase, and p38-increased after CdCl{sub 2} exposure, whereas treatment with the MAPK/ERK kinase inhibitor U0126 and the p38 inhibitor SB203580 suppressed the accumulation and phosphorylation of c-Fos. We mutated Ser362 to alanine (S362A), Ser374 to alanine (S374A), and both residues to alanines (S362A/S374A) to inhibit potential phosphorylation of c-Fos at these sites. S374A or double S362A/S374A mutations reduced c-Fos level markedly, but S362A mutation did not. On the other hand, S362A/S374A mutations induced a more pronounced reduction in c-Fos DNA-binding activity than S374A mutation. These results suggest that while Ser374 phosphorylation seems to play a role in c-Fos stabilization, phosphorylation at two C-terminal serine residues is required for the transcriptional activation of c-Fos in HK-2 cells treated with CdCl{sub 2}.

  19. Long-term outcome in children with primary distal renal tubular acidosis.

    PubMed

    Bajpai, Anurag; Bagga, Arvind; Hari, Pankaj; Bardia, Aditya; Mantan, Mukta

    2005-04-01

    To evaluate complications in adequately treated children with distal renal tubular acidosis (RTA) and to identify factors influencing their development. Records of patients with primary distal RTA followed for 2 or more years at this hospital were reviewed. Case records were examined for age at onset of symptoms and at initiation of treatment, treatment details, follow-up and complications. Height, weight and growth velocity were expressed as standard deviation score (SDS) during different periods of follow-up. Regression analysis was performed to evaluate factors influencing increase in height and weight SDS. P value of less than 0.05 was considered significant. Of 18 patients (eleven boys), the diagnosis was established at the median (range) age of 6 yr (1.5-13 yr). These patients were followed up for a median (range) period of 4 yr (2-18.5 yr). Short stature (height SDS <-2) was noted in all patients at the time of diagnosis with median (range) height SDS of -5.2(-7.5 - -0.4). All patients had failure to thrive with median (range) weight SDS of -3(-5.7 - -1.5). Height SDS increased by median (range) of 2 (1.2-5.5) to become -2.7(-4.8 - -1.1) at last follow-up. Weight SDS increased by median (range) of 0.9 (-0.6 - 2.8) to become -2.4 (-4 - -0.5). Median (range) growth velocity SDS decreased from 3 (1-16) during first year of treatment to 1(-0.3 - 7) at four years with an increase in mean height SDS by 1.3 during the first two years of treatment. Height SDS at last follow-up was not influenced by the age at initiation of treatment, follow-up duration, initial height SDS or severity of acidosis at diagnosis. Increase in height SDS correlated negatively with base excess and height SDS at diagnosis, and positively with follow-up duration on univariate analyses. Initial height SDS was the only factor that influenced increase in height SDS on multivariate analyses. Increase in weight SDS was negatively correlated with base excess and initial weight SDS with significant

  20. A case of Sjögren's syndrome complicated by nephrogenic diabetes insipidus and renal tubular acidosis.

    PubMed

    Hirose, W; Kawagoe, M

    2000-09-01

    Abstract We describe the case of a 46-year-old woman with Sjögren's syndrome (SS) presenting with a 6-year history of polyuria and polydipsia. Laboratory data revealed hyperchloremic metabolic acidosis, a normal anion gap, and an inability to acidify urine following an acid loading test and to concentrate the urine in response to water deprivation and antidiuretic hormone administration. Lymphocyte infiltration in the interstitium was found on renal biopsy. These findings allowed us to diagnose distal renal tubular acidosis (RTA) and nephrogenic diabetes insipidus (NDI). Steroid pulse therapy resulted in normalization of the blood pH, but failed to remit the inability to concentrate the urine. These observations suggest therapeutic applications for RTA in SS, and that further investigation is required to design a therapeutic strategy for NDI in SS.

  1. Specific estrogen-induced cell proliferation of cultured Syrian hamster renal proximal tubular cells in serum-free chemically defined media

    SciTech Connect

    Oberley, T.D.; Lauchner, L.J.; Pugh, T.D.; Gonzalez, A.; Goldfarb, S. ); Li, S.A.; Li, J.J. )

    1989-03-01

    It has long been recognized that the renal proximal tubular epithelium of the hamster is a bona fide estrogen target tissue. The effect of estrogens on the growth of proximal tubule cell explants and dissociated single cells derived from these explant outgrowths has been studied in culture. Renal tubular cells were grown on a PF-HR-9 basement membrane under serum-free chemically defined culture conditions. At 7-14 days in culture, cell number was enhanced 3-fold in the presence of either 17{beta}-estradiol or diethylstilbestrol. A similar 3-fold increase in cell number was also seen at 1 nM 17{beta}-estradiol in subcultured dissociated single tubular cells derived from hamster renal tubular explant outgrowths at 21 days in culture. Concomitant exposure of tamoxifen at 3-fold molar excess in culture completely abolished the increase in cell number seen with 17{beta}-estradiol. The proliferation effect of estrogens on proximal tubular cell growth appears to be species specific since 17{beta}-estradiol did not alter the growth of either rat or guinea pig proximal tubules in culture. In addition, at 7-10 days in culture in the presence of 17{beta}-estradiol, ({sup 3}H)thymidine labeling of hamster tubular cells was enhanced 3-fold. These results clearly indicate that estrogens can directly induce primary epithelial cell proliferation at physiologic concentrations and provide strong additional evidence for an important hormonal role in the neoplastic transformation of the hamster kidney.

  2. Heme oxygenase-1 modulates the expression of the anti-angiogenic chemokine CXCL-10 in renal tubular epithelial cells.

    PubMed

    Datta, Dipak; Dormond, Olivier; Basu, Aninda; Briscoe, David M; Pal, Soumitro

    2007-10-01

    The turnover and repair of peritubular capillaries is essential for the maintenance of normal renal tubular structure and function. Following injury, ineffective capillary repair/angiogenesis may result in chronic disease, whereas effective repair attenuates the injury process. Thus the process of healing in the kidney is likely dependent on an intricate balance between angiogenic and anti-angiogenic factors to maintain the renal microvasculature. We investigated the role of cytoprotective heme oxygenase-1 (HO-1) in the regulation of chemokines in human renal proximal tubular epithelial cells (RPTEC). Transfection of RPTEC with a HO-1 overexpression plasmid promoted a marked induction in the mRNA expression of the anti-angiogenic chemokine CXCL-10, along with angiogenic chemokines CXCL-8 and CCL-2. Utilizing a CXCL-10 promoter luciferase construct, we observed that HO-1-induced CXCL-10 expression is regulated at the transcriptional level. However, with increases in concentrations and time intervals of HO-1 induction, there was a marked decrease in CXCL-10 expression. Using pharmacological inhibitors, we found that HO-1-induced early robust CXCL-10 transcription is mediated through the PKC signaling pathway. To evaluate the functional significance of HO-1-induced CXCL-10 release, we cultured human vascular endothelial cells in the absence and presence of culture supernatants of the HO-1 plasmid-transfected RPTEC. We found that early (24 h) supernatants of the HO-1 plasmid-transfected cells (RPTEC) inhibited endothelial cell proliferation, and this effect was blocked by addition of a CXCL-10 neutralizing antibody. Thus HO-1 can regulate the expression of the anti-angiogenic CXCL-10 and may alter a critical balance between angiogenic vs. anti-angiogenic factors that are important to maintain renal microvasculature during injury.

  3. Hyperosmolarity enhanced susceptibility to renal tubular fibrosis by modulating catabolism of type I transforming growth factor-beta receptors.

    PubMed

    Chiang, Tai-An; Yang, Yu-Lin; Yang, Ya-Ying; Hu, Min-Hsiu; Wu, Pei-Fen; Liu, Shu-Fen; Huang, Ruay-Ming; Liao, Tung-Nan; Hung, Chien-Ya; Hung, Tsung-Jen; Lee, Tao-Chen

    2010-03-01

    Hyperosmolarity plays an essential role in the pathogenesis of diabetic tubular fibrosis. However, the mechanism of the involvement of hyperosmolarity remains unclear. In this study, mannitol was used to evaluate the effects of hyperosmolarity on a renal distal tubule cell line (MDCK). We investigated transforming growth factor-beta receptors and their downstream fibrogenic signal proteins. We show that hyperosmolarity significantly enhances the susceptibility to exogenous transforming growth factor (TGF)-beta1, as mannitol (27.5 mM) significantly enhanced the TGF-beta1-induced increase in fibronectin levels compared with control experiments (5.5 mM). Specifically, hyperosmolarity induced tyrosine phosphorylation on TGF-beta RII at 336 residues in a time (0-24 h) and dose (5.5-38.5 mM) dependent manner. In addition, hyperosmolarity increased the level of TGF-beta RI in a dose- and time-course dependent manner. These observations may be closely related to decreased catabolism of TGF-beta RI. Hyperosmolarity significantly downregulated the expression of an inhibitory Smad (Smad7), decreased the level of Smurf 1, and reduced ubiquitination of TGF-beta RI. In addition, through the use of cycloheximide and the proteasome inhibitor MG132, we showed that hyperosmolarity significantly increased the half-life and inhibited the protein level of TGF-beta RI by polyubiquitination and proteasomal degradation. Taken together, our data suggest that hyperosmolarity enhances cellular susceptibility to renal tubular fibrosis by activating the Smad7 pathway and increasing the stability of type I TGF-beta receptors by retarding proteasomal degradation of TGF-beta RI. This study clarifies the mechanism underlying hyperosmotic-induced renal fibrosis in renal distal tubule cells. (c) 2010 Wiley-Liss, Inc.

  4. Total Coumarins from Hydrangea paniculata Protect against Cisplatin-Induced Acute Kidney Damage in Mice by Suppressing Renal Inflammation and Apoptosis

    PubMed Central

    Jie, Ma; Jingzhi, Yang; Dongjie, Wang; Dongming, Zhang

    2017-01-01

    Aim. Hydrangea paniculata (HP) Sieb. is a medical herb which is widely distributed in southern China, and current study is to evaluate renal protective effect of aqueous extract of HP by cisplatin-induced acute kidney injury (AKI) in animal model and its underlying mechanisms. Materials and Methods. HP extract was prepared and the major ingredients were coumarin glycosides. AKI mouse models were established by single i.p. injection of 20 mg/kg cisplatin, and HP was orally administrated for total five times. The renal biochemical functions, pathological staining, kidney oxidative stress, and inflammatory status were measured. Apoptosis of tubular cells and infiltration of macrophages and neutrophils were also tested. Results. HP administration could improve the renal function by decreasing concentration of blood urea nitrogen (BUN) and creatinine and attenuates renal oxidative stress and tubular pathological injury and apoptosis; further research demonstrated that HP could inhibit the overproduction of proinflammatory cytokines and regulate caspase and BCL-2 family proteins. HP also reduced renal infiltration of macrophages and neutrophils, and its effect might be by downregulating phosphorylation of ERK1/2 and stat3 signaling pathway. Conclusions. This present study suggests that HP could ameliorate cisplatin induced kidney damage by antioxidation and suppressing renal inflammation and tubular cell apoptosis. PMID:28367225

  5. IL-37 inhibits IL-18-induced tubular epithelial cell expression of pro-inflammatory cytokines and renal ischemia-reperfusion injury.

    PubMed

    Yang, Yunbo; Zhang, Zhu-Xu; Lian, Dameng; Haig, Aaron; Bhattacharjee, Rabindra N; Jevnikar, Anthony M

    2015-02-01

    Cytokines and chemokines produced by tubular epithelial and infiltrating cells are critical to inflammation in renal ischemia-reperfusion injury. IL-37, a newly described IL-1 family member, inhibits IL-18-dependent pro-inflammatory cytokine production by its binding to IL-18 receptors and IL-18 binding protein. The potential role of IL-37 in renal ischemia-reperfusion injury is unknown. Here we found that exposure of tubular epithelial cells to exogenous IL-37 downregulated hypoxia and the IL-18-induced expression of TNFα, IL-6, and IL-1β. Importantly, human PT-2 tubular epithelial cells have inducible expression of IL-37. Moreover, pro-inflammatory cytokine expression was augmented in IL-37 mRNA-silenced tubular epithelial cells and inhibited by transfection with pCMV6-XL5-IL-37. In a mouse ischemic injury model, transgenic expression of human IL-37 inhibited kidney expression of TNFα, IL-6, and IL-1β and improved mononuclear cell infiltration, kidney injury, and function. Thus, human tubular epithelial cells express the IL-18 contra-regulatory protein IL-37 as an endogenous control mechanism to reduce inflammation. Augmenting kidney IL-37 may represent a novel strategy to suppress renal injury responses and promote kidney function after renal ischemic injury and transplantation.

  6. Cell-specific delivery of a transforming growth factor-beta type I receptor kinase inhibitor to proximal tubular cells for the treatment of renal fibrosis.

    PubMed

    Prakash, Jai; de Borst, Martin H; van Loenen-Weemaes, Annemiek M; Lacombe, Marie; Opdam, Frank; van Goor, Harry; Meijer, Dirk K F; Moolenaar, Frits; Poelstra, Klaas; Kok, Robbert J

    2008-10-01

    Activation of tubular epithelial cells by transforming growth factor-beta (TGF-beta) plays an important role in the pathogenesis of renal tubulointerstitial fibrosis. We developed a renally accumulating conjugate of a TGF-beta type-I receptor kinase inhibitor (TKI) and evaluated its efficacy in vitro and in vivo. TKI was conjugated to the protein Lysozyme (LZM) via a platinum-based linker. TKI-LZM was evaluated in human tubular cells (HK-2) for its anti-fibrotic activity. Plasma, kidney and urine drug levels after a single intravenous dose of TKI-LZM in rats were determined by HPLC or immunodetection. Anti-fibrotic effects of TKI-LZM were examined in the unilateral ureteral obstruction (UUO) model. TKI-LZM conjugate was successfully synthesized at an 1:1 drug/carrier ratio, and inhibited TGF-beta1-induced procollagen-1alpha1 gene expression in HK-2 cells. In vivo, TKI-LZM accumulated rapidly in tubular cells and provided a local depot for 3 days. Interestingly, a single dose of TKI-LZM inhibited the activation of tubular cells and fibroblasts in UUO rats and reduced renal inflammation. In contrast, free TKI at an equimolar (low) dosage exhibited little effects. Inhibition of TGF-beta signaling by local drug delivery is a promising antifibrotic strategy, and demonstrated the important role of tubular activation in renal fibrosis.

  7. Disparate effects of roscovitine on renal tubular epithelial cell apoptosis and senescence: implications for autosomal dominant polycystic kidney disease.

    PubMed

    Park, Jin-Young; Park, See-Hyoung; Weiss, Robert H

    2009-01-01

    Control of apoptosis in autosomal dominant polycystic kidney disease (ADPKD) and in at least some cancers is likely regulated by the endogenous cyclin kinase inhibitor p21, levels of this protein being decreased in ADPKD and increased in many malignancies. The cyclin kinase inhibitor roscovitine has shown efficacy in treatment of murine PKD. We asked how a single agent can be efficacious in both PKD and cancer. Renal tubular epithelial cells were incubated at diverse roscovitine concentrations; apoptosis and senescence were measured. Subsequently, levels of pro- and antiapoptotic proteins were evaluated. Renal tubular epithelial cells exposed to 'low' concentrations of roscovitine showed minimal apoptosis in association with markedly increased levels of the antiapoptotic protein p21, and these cells became senescent. Conversely, cells exposed to 'high' levels of roscovitine became apoptotic. The mechanism of antiapoptosis and senescence with 'low'-dose roscovitine involves augmentation of the antiapoptotic proteins. Data in this study provide a mechanistic explanation of how roscovitine is effective in PKD, and suggest that further study of this agent should focus on assessment of dose response. Furthermore, our discovery of senescence induced by a PKD effective drug suggests a new area of therapeutic investigation in this disease. (c) 2008 S. Karger AG, Basel.

  8. Disparate Effects of Roscovitine on Renal Tubular Epithelial Cell Apoptosis and Senescence: Implications for Autosomal Dominant Polycystic Kidney Disease

    PubMed Central

    Park, Jin-Young; Park, See-Hyoung; Weiss, Robert H.

    2009-01-01

    Background/Aims Control of apoptosis in autosomal dominant polycystic kidney disease (ADPKD) and in at least some cancers is likely regulated by the endogenous cyclin kinase inhibitor p21, levels of this protein being decreased in ADPKD and increased in many malignancies. The cyclin kinase inhibitor roscovitine has shown efficacy in treatment of murine PKD. We asked how a single agent can be efficacious in both PKD and cancer. Methods Renal tubular epithelial cells were incubated at diverse roscovitine concentrations; apoptosis and senescence were measured. Subsequently, levels of pro- and antiapoptotic proteins were evaluated. Results Renal tubular epithelial cells exposed to ‘low’ concentrations of roscovitine showed minimal apoptosis in association with markedly increased levels of the antiapoptotic protein p21, and these cells became senescent. Conversely, cells exposed to ‘high’ levels of roscovitine became apoptotic. The mechanism of antiapoptosis and senescence with ‘low’-dose roscovitine involves augmentation of the antiapoptotic proteins. Conclusions Data in this study provide a mechanistic explanation of how roscovitine is effective in PKD, and suggest that further study of this agent should focus on assessment of dose response. Furthermore, our discovery of senescence induced by a PKD effective drug suggests a new area of therapeutic investigation in this disease. PMID:19066425

  9. Enhanced sodium-dependent extrusion of magnesium in mutant cells established from a mouse renal tubular cell line.

    PubMed

    Watanabe, Masaru; Konishi, Masato; Ohkido, Ichiro; Matsufuji, Senya

    2005-10-01

    To study the regulatory mechanisms of intracellular Mg(2+) concentration ([Mg(2+)](i)) in renal tubular cells as well as in other cell types, we established a mutant strain of mouse renal cortical tubular cells that can grow in culture media with very high extracellular Mg(2+) concentrations ([Mg(2+)](o) > 100 mM: 101Mg-tolerant cells). [Mg(2+)](i) was measured with a fluorescent indicator furaptra (mag-fura 2) in wild-type and 101Mg-tolerant cells. The average level of [Mg(2+)](i) in the 101Mg-tolerant cells was kept lower than that in the wild-type cells either at 51 mM or 1 mM [Mg(2+)](o). When [Mg(2+)](o) was lowered from 51 to 1 mM, the decrease in [Mg(2+)](i) was significantly faster in the 101Mg-tolerant cells than in the wild-type cells. These differences between the 101Mg-tolerant cells and the wild-type cells were abolished in the absence of extracellular Na(+) or in the presence of imipramine, a known inhibitor of Na(+)/Mg(2+) exchange. We conclude that Na(+)-dependent Mg(2+) transport activity is enhanced in the 101Mg-tolerant cells. The enhanced Mg(2+) extrusion may prevent [Mg(2+)](i) increase to higher levels and may be responsible for the Mg(2+) tolerance.

  10. Pycnogenol modulates apoptosis by suppressing oxidative stress and inflammation in high glucose-treated renal tubular cells.

    PubMed

    Kim, You Jung; Kim, Young Ae; Yokozawa, Takako

    2011-09-01

    Compelling evidence indicates that polyphenolic antioxidants protect against diabetic nephropathy. Pycnogenol is made up of flavonoids, mainly procyanidins and phenolic compounds, and is a known powerful antioxidant. Hyperglycemia is characteristic of diabetic nephropathy and induces renal tubular cell apoptosis. Thus, in this study, we used high glucose-treated renal tubular cells to investigate the protective action of pycnogenol against high glucose-induced apoptosis and diabetic nephropathy. We also sought to further delineate the underlying mechanisms elicited by oxidative stress and inflammation and suppressed by pycnogenol. Results show that pycnogenol significantly suppressed the high glucose-induced morphological changes and the reduction in cell viability associated with cytotoxicity. Bcl2/Bax protein levels indicated pycnogenol's anti-apoptotic effect against high glucose-induced apoptotic cell death. In addition, several key markers of oxidative stress and inflammation were measured for pycnogenol's beneficial effects. Results indicate pycnogenol's anti-oxidative and anti-inflammatory efficacy in suppressing lipid peroxidation, total reactive species (RS), superoxide ((·)O(2)), nitric oxide (NO(·)), peroxynitrite (ONOO(-)), pro-inflammatory inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and nuclear factor-kappa B (NF-κB) nuclear translocation. Based on these results, we conclude that pycnogenol's anti-oxidative and anti-inflammatory properties underlie its anti-apoptotic effects, suggesting further investigation of pycnogenol as a promising treatment against diabetic nephropathy.

  11. Alpha-enolase on apical surface of renal tubular epithelial cells serves as a calcium oxalate crystal receptor

    NASA Astrophysics Data System (ADS)

    Fong-Ngern, Kedsarin; Thongboonkerd, Visith

    2016-10-01

    To search for a strategy to prevent kidney stone formation/recurrence, this study addressed the role of α-enolase on apical membrane of renal tubular cells in mediating calcium oxalate monohydrate (COM) crystal adhesion. Its presence on apical membrane and in COM crystal-bound fraction was confirmed by Western blotting and immunofluorescence staining. Pretreating MDCK cells with anti-α-enolase antibody, not isotype-controlled IgG, dramatically reduced cell-crystal adhesion. Immunofluorescence staining also confirmed the direct binding of purified α-enolase to COM crystals at {121} > {100} > {010} crystal faces. Coating COM crystals with urinary proteins diminished the crystal binding capacity to cells and purified α-enolase. Moreover, α-enolase selectively bound to COM, not other crystals. Chemico-protein interactions analysis revealed that α-enolase interacted directly with Ca2+ and Mg2+. Incubating the cells with Mg2+ prior to cell-crystal adhesion assay significantly reduced crystal binding on the cell surface, whereas preincubation with EDTA, a divalent cation chelator, completely abolished Mg2+ effect, indicating that COM and Mg2+ competitively bind to α-enolase. Taken together, we successfully confirmed the role of α-enolase as a COM crystal receptor to mediate COM crystal adhesion at apical membrane of renal tubular cells. It may also serve as a target for stone prevention by blocking cell-crystal adhesion and stone nidus formation.

  12. TWEAK Activates the Non-Canonical NFκB Pathway in Murine Renal Tubular Cells: Modulation of CCL21

    PubMed Central

    Sanz, Ana B.; Sanchez-Niño, Maria D.; Izquierdo, Maria C.; Jakubowski, Aniela; Justo, Pilar; Blanco-Colio, Luis M.; Ruiz-Ortega, Marta; Selgas, Rafael; Egido, Jesús; Ortiz, Alberto

    2010-01-01

    TWEAK is a member of the TNF superfamily of cytokines that contribute to kidney tubulointerstitial injury. It has previously been reported that TWEAK induces transient nuclear translocation of RelA and expression of RelA-dependent cytokines in renal tubular cells. Additionally, TWEAK induced long-lasting NFκB activation suggestive of engagement of the non-canonical NFκB pathway. We now explore TWEAK-induced activation of NFκB2 and RelB, as well as expression of CCL21, a T-cell chemotactic factor, in cultured murine tubular epithelial cells and in healthy kidneys in vivo. In cultured tubular cells, TWEAK and TNFα activated different DNA-binding NFκB complexes. TWEAK-induced sustained NFκB activation was associated with NFκB2 p100 processing to p52 via proteasome and nuclear translocation and DNA-binding of p52 and RelB. TWEAK, but not TNFα used as control), induced a delayed increase in CCL21a mRNA (3.5±1.22-fold over control) and CCL21 protein (2.5±0.8-fold over control), which was prevented by inhibition of the proteasome, or siRNA targeting of NIK or RelB, but not by RelA inhibition with parthenolide. A second NFκB2-dependent chemokine, CCL19, was upregulates by TWEAK, but not by TNFα. However, both cytokines promoted chemokine RANTES expression (3-fold mRNA at 24 h). In vivo, TWEAK induced nuclear NFκB2 and RelB translocation and CCL21a mRNA (1.5±0.3-fold over control) and CCL21 protein (1.6±0.5-fold over control) expression in normal kidney. Increased tubular nuclear RelB and tubular CCL21 expression in acute kidney injury were decreased by neutralization (2±0.9 vs 1.3±0.6-fold over healthy control) or deficiency of TWEAK (2±0.9 vs 0.8±0.6-fold over healthy control). Moreover, anti-TWEAK treatment prevented the recruitment of T cells to the kidney in this model (4.1±1.4 vs 1.8±1-fold over healthy control). Our results thus identify TWEAK as a regulator of non-canonical NFκB activation and CCL21 expression in tubular cells thus promoting

  13. Dragon (repulsive guidance molecule RGMb) inhibits E-cadherin expression and induces apoptosis in renal tubular epithelial cells.

    PubMed

    Liu, Wenjing; Li, Xiaoling; Zhao, Yueshui; Meng, Xiao-Ming; Wan, Chao; Yang, Baoxue; Lan, Hui-Yao; Lin, Herbert Y; Xia, Yin

    2013-11-01

    Dragon is one of the three members of the repulsive guidance molecule (RGM) family, i.e. RGMa, RGMb (Dragon), and RGMc (hemojuvelin). We previously identified the RGM members as bone morphogenetic protein (BMP) co-receptors that enhance BMP signaling. Our previous studies found that Dragon is highly expressed in the tubular epithelial cells of mouse kidneys. However, the roles of Dragon in renal epithelial cells are yet to be defined. We now show that overexpression of Dragon increased cell death induced by hypoxia in association with increased cleaved poly(ADP-ribose) polymerase and cleaved caspase-3 levels in mouse inner medullary collecting duct (IMCD3) cells. Dragon also inhibited E-cadherin expression but did not affect epithelial-to-mesenchymal transition induced by TGF-β in IMCD3 cells. Previous studies suggest that the three RGM members can function as ligands for the receptor neogenin. Interestingly, our present study demonstrates that the Dragon actions on apoptosis and E-cadherin expression in IMCD3 cells were mediated by the neogenin receptor but not through the BMP pathway. Dragon expression in the kidney was up-regulated by unilateral ureteral obstruction in mice. Compared with wild-type mice, heterozygous Dragon knock-out mice exhibited 45-66% reduction in Dragon mRNA expression, decreased epithelial apoptosis, and increased tubular E-cadherin expression and had attenuated tubular injury after unilateral ureteral obstruction. Our results suggest that Dragon may impair tubular epithelial integrity and induce epithelial apoptosis both in vitro and in vivo.

  14. Response of human renal tubular cells to cyclosporine and sirolimus: a toxicogenomic study.

    PubMed

    Pallet, Nicolas; Rabant, Marion; Xu-Dubois, Yi-Chun; Lecorre, Delphine; Mucchielli, Marie-Hélène; Imbeaud, Sandrine; Agier, Nicolas; Hertig, Alexandre; Thervet, Eric; Legendre, Christophe; Beaune, Philippe; Anglicheau, Dany

    2008-06-01

    The molecular mechanisms involved in the potentially nephrotoxic response of tubular cells to immunosuppressive drugs remain poorly understood. Transcriptional profiles of human proximal tubular cells exposed to cyclosporine A (CsA), sirolimus (SRL) or their combination, were established using oligonucleotide microarrays. Hierarchical clustering of genes implicated in fibrotic processes showed a clear distinction between expression profiles with CsA and CsA+SRL treatments on the one hand and SRL treatment on the other. Functional analysis found that CsA and CsA+SRL treatments preferentially alter biological processes located at the cell membrane, such as ion transport or signal transduction, whereas SRL modifies biological processes within the nucleus and related to transcriptional activity. Genome wide expression analysis suggested that CsA may induce an endoplasmic reticulum (ER) stress in tubular cells in vitro. Moreover we found that CsA exposure in vivo is associated with the upregulation of the ER stress marker BIP in kidney transplant biopsies. In conclusion, this toxicogenomic study highlights the molecular interaction networks that may contribute to the tubular response to CsA and SRL. These results may also offer a new working hypothesis for future research in the field of CsA nephrotoxicity. Further studies are needed to evaluate if ER stress detection in tubular cells in human biopsies can predict CsA nephrotoxicity.

  15. Response of human renal tubular cells to cyclosporine and sirolimus: A toxicogenomic study

    SciTech Connect

    Pallet, Nicolas Rabant, Marion; Xu-Dubois, Yi-Chun; LeCorre, Delphine; Mucchielli, Marie-Helene; Imbeaud, Sandrine; Agier, Nicolas; Thervet, Eric; Legendre, Christophe; Beaune, Philippe; Anglicheau, Dany

    2008-06-01

    The molecular mechanisms involved in the potentially nephrotoxic response of tubular cells to immunosuppressive drugs remain poorly understood. Transcriptional profiles of human proximal tubular cells exposed to cyclosporine A (CsA), sirolimus (SRL) or their combination, were established using oligonucleotide microarrays. Hierarchical clustering of genes implicated in fibrotic processes showed a clear distinction between expression profiles with CsA and CsA + SRL treatments on the one hand and SRL treatment on the other. Functional analysis found that CsA and CsA + SRL treatments preferentially alter biological processes located at the cell membrane, such as ion transport or signal transduction, whereas SRL modifies biological processes within the nucleus and related to transcriptional activity. Genome wide expression analysis suggested that CsA may induce an endoplasmic reticulum (ER) stress in tubular cells in vitro. Moreover we found that CsA exposure in vivo is associated with the upregulation of the ER stress marker BIP in kidney transplant biopsies. In conclusion, this toxicogenomic study highlights the molecular interaction networks that may contribute to the tubular response to CsA and SRL. These results may also offer a new working hypothesis for future research in the field of CsA nephrotoxicity. Further studies are needed to evaluate if ER stress detection in tubular cells in human biopsies can predict CsA nephrotoxicity.

  16. Hypoxia response and VEGF-A expression in human proximal tubular epithelial cells in stable and progressive renal disease.

    PubMed

    Rudnicki, Michael; Perco, Paul; Enrich, Julia; Eder, Susanne; Heininger, Dorothea; Bernthaler, Andreas; Wiesinger, Martin; Sarközi, Rita; Noppert, Susie-Jane; Schramek, Herbert; Mayer, Bernd; Oberbauer, Rainer; Mayer, Gert

    2009-03-01

    Proteinuria, inflammation, chronic hypoxia, and rarefaction of peritubular capillaries contribute to the progression of renal disease by affecting proximal tubular epithelial cells (PTECs). To study the transcriptional response that separates patients with a stable course from those with a progressive course of disease, we isolated PTECs by laser capture microdissection from cryocut tissue sections of patients with proteinuric glomerulopathies (stable n=20, progressive n=11) with a median clinical follow-up of 26 months. Gene-expression profiling and a systems biology analysis identified activation of intracellular vascular endothelial growth factor (VEGF) signaling and hypoxia response pathways in progressive patients, which was associated with upregulation of hypoxia-inducible-factor (HIF)-1alpha and several HIF target genes, such as transferrin, transferrin-receptor, p21, and VEGF-receptor 1, but downregulation of VEGF-A. The inverse expression levels of HIF-1alpha and VEGF-A were significantly superior in predicting clinical outcome as compared with proteinuria, renal function, and degree of tubular atrophy and interstitial fibrosis at the time of biopsy. Interactome analysis showed the association of attenuated VEGF-A expression with the downregulation of genes that usually stimulate VEGF-A expression, such as epidermal growth factor (EGF), insulin-like growth factor-1 (IGF-1), and HIF-2alpha. In vitro experiments confirmed the positive regulatory effect of EGF and IGF-1 on VEGF-A transcription in human proximal tubular cells. Thus, in progressive but not in stable proteinuric kidney disease, human PTECs show an attenuated VEGF-A expression despite an activation of intracellular hypoxia response and VEGF signaling pathways, which might be due to a reduced expression of positive coregulators, such as EGF and IGF-1.

  17. Influence of urinary sodium excretion on the clinical assessment of renal tubular calcium reabsorption in hypercalcaemic man.

    PubMed

    Ralston, S H; Gardner, M D; Dryburgh, F J; Cowan, R A; Boyle, I T

    1986-06-01

    The relation between urinary sodium excretion (NaE) and renal tubular calcium reabsorption (TmCa/GFR) was assessed in patients with hypercalcaemia associated with malignancy and primary hyperparathyroidism. On acute saline loading of seven normally hydrated patients with primary hyperparathyroidism and five patients with malignancy, raised values of TmCa/GFR were reduced to normal in most cases, in association with increases in NaE. The reduction in TmCa/GFR, which occurred, may have been due to a reduction in proximal tubular calcium reabsorption associated with sodium: this would have obscured the effect of humorally mediated increases in distal tubular calcium reabsorption, which are stimulated either by parathyroid hormone or by a putative humoral mediator in hypercalcaemia of malignancy. In patients who were normally hydrated NaE and TmCa/GFR were not significantly correlated. When data were included from patients who were dehydrated and from those undergoing acute saline loading, significant inverse correlations between NaE and TmCa/GFR were observed both in primary hyperparathyroidism (r = -0.49; p less than 0.02) and malignancy (r = -0.60; p less than 0.001). In clinical practice changes in TmCa/GFR associated with sodium seem to be of minor importance under normal circumstances, but they become evident at the upper and lower extremes of urinary sodium excretion. In clinical studies of renal calcium handling urinary sodium excretion must also be assessed, as interpreting TmCa/GFR data is difficult in states of excessive sodium loading or depletion.

  18. Influence of urinary sodium excretion on the clinical assessment of renal tubular calcium reabsorption in hypercalcaemic man.

    PubMed Central

    Ralston, S H; Gardner, M D; Dryburgh, F J; Cowan, R A; Boyle, I T

    1986-01-01

    The relation between urinary sodium excretion (NaE) and renal tubular calcium reabsorption (TmCa/GFR) was assessed in patients with hypercalcaemia associated with malignancy and primary hyperparathyroidism. On acute saline loading of seven normally hydrated patients with primary hyperparathyroidism and five patients with malignancy, raised values of TmCa/GFR were reduced to normal in most cases, in association with increases in NaE. The reduction in TmCa/GFR, which occurred, may have been due to a reduction in proximal tubular calcium reabsorption associated with sodium: this would have obscured the effect of humorally mediated increases in distal tubular calcium reabsorption, which are stimulated either by parathyroid hormone or by a putative humoral mediator in hypercalcaemia of malignancy. In patients who were normally hydrated NaE and TmCa/GFR were not significantly correlated. When data were included from patients who were dehydrated and from those undergoing acute saline loading, significant inverse correlations between NaE and TmCa/GFR were observed both in primary hyperparathyroidism (r = -0.49; p less than 0.02) and malignancy (r = -0.60; p less than 0.001). In clinical practice changes in TmCa/GFR associated with sodium seem to be of minor importance under normal circumstances, but they become evident at the upper and lower extremes of urinary sodium excretion. In clinical studies of renal calcium handling urinary sodium excretion must also be assessed, as interpreting TmCa/GFR data is difficult in states of excessive sodium loading or depletion. PMID:3722417

  19. Leukocyte involvement in renal reperfusion-induced liver damage.

    PubMed

    Khastar, Hossein; Kadkhodaee, Mehri; Sadeghipour, Hamid Reza; Seifi, Behjat; Hadjati, Jamshid; Delavari, Fatemeh; Soleimani, Manoocher

    2011-01-01

    Renal ischemia-reperfusion (IR) induces organ damage in remote organs. The aim of this study was to assess the role of leukocytes in the induction of liver damage after renal IR injury. Inbred mice were subjected to either sham operation or bilateral renal IR injury (60 min ischemia followed by 3 h reperfusion). Mice were then anesthetized for collection of leukocytes by heart puncture. Isolated leukocytes were transferred to two other groups: intact recipient mice that received leukocytes from IR mice and intact recipient mice that received leukocytes from sham-operated control mice. After 24 h, recipient mice were anesthetized and samples were collected. Alanine aminotransferase, aspartate aminotransferase, and hepatic malondialdehyde increased significantly, and hepatic glutathione decreased significantly in intact recipient mice that received leukocytes from IR mice in comparison with intact recipient mice that received leukocytes from sham-operated control mice. Loss of normal liver architecture, cytoplasmic vacuolization, and focal infiltration of leukocytes were seen. These results suggest that leukocytes are one of the possible factors that contribute to liver damage after renal IR injury and this damage is partly due to the induction of oxidative stress.

  20. Increased hematocrit mitigates ischemic renal damage in the splenectomized dog.

    PubMed

    Bell, R D; Mandal, A K

    1989-03-01

    Splenectomy (SPLX) prevents ischemic acute tubular necrosis (ATN) and peritubular capillary (PTC) congestion. This study attempts to reverse the protective effect of splenectomy in the ischemic model of ATN by increasing hematocrit before inducing ATN. Sham-SPLX, SPLX, and SPLX dogs given packed red cells to elevate hematocrit by 30% (SPLX-high hematocrit) received bilateral renal artery obstruction (RAO) for 120 minutes. Renal function was tested for 6 days post-RAO. Hematocrit in the SPLX-high hematocrit group was greater (p less than .05) than the SPLX-RAO group but did not differ from the non-SPLX group. All groups had different (p less than .05) serum creatinine levels for 48 hours post-RAO, and untreated animals differed from all the others at 144 hours. Serum creatinine was highest in untreated, lowest in SPLX-high hematocrit, and intermediate in noninfused SPLX animals. The same pattern was observed in blood urea nitrogen, creatinine clearance and renal histopathology. Fractional excretion of sodium in the SPLX groups was six times that in the intact animals (p less than .05), irrespective of hematocrit level. We conclude that increased hematocrit is protective in ischemic ATN, and does not promote PTC congestion or ATN in the SPLX animal. In addition, the protective effect of splenectomy may be mediated, in part, by mechanism(s) that alter sodium transport or osmolar excretion.

  1. Activation of liver X receptor inhibits OCT2-mediated organic cation transport in renal proximal tubular cells.

    PubMed

    Wongwan, Teerasak; Kittayaruksakul, Suticha; Asavapanumas, Nithi; Chatsudthipong, Varanuj; Soodvilai, Sunhapas

    2017-07-25

    Liver X receptor (LXR) is transcriptional factor that plays an important role in the regulation of energy metabolism such as cholesterol, lipid, and glucose metabolism as well as membrane transporters and channels. Using both in vitro and in vivo models, LXR regulation of the expression and function of renal organic cation transporter 2 (OCT2) was observed. Synthetic LXR agonist (GW3965) and endogenous LXR agonist (22R-hydroxycholesterol) significantly reduced the uptake of (3)H-MPP(+), a prototypic substrate of OCT2, in both OCT2- Chinese hamster ovary K1 and human renal proximal tubular cells (RPTEC/TERT1). GW3965 decreased transport activity of OCT2 via a reduction of the maximal transport rate of MPP(+) without affecting transporter affinity. The inhibitory effect of GW3965 was attenuated by co-treatment with LXR antagonist (fenofibrate) indicating the inhibition was LXR-dependent mechanism. In addition, co-treatment with a retinoic X receptor (RXR) ligand, 9-cis retinoic acid enhanced the inhibitory effect of GW3965, indicating negative regulation of OCT2 transport activity by the LXR/RXR complex. Treatment RPTEC/TERT1 cells with GW3965 significantly reduced OCT2 protein expression without changing mRNA expression. In parallel, the effect of LXR activation on OCT2 function was investigated in intact mouse kidney. Treating mice with 50 mg/kg BW T0901317 for 14 days significantly decreased (3)H-MPP(+) uptake into renal cortical slices, correlating with decreased OCT2 protein expression in renal cortex without changes in mRNA expression levels. Taken together, LXR/RXR activation downregulates the protein expression and function of OCT2 in renal proximal tubule, suggesting LXR might affect the total profile of renal excretion of cationic compounds.

  2. Renal tissue damage induced by focused shock waves

    NASA Astrophysics Data System (ADS)

    Ioritani, N.; Kuwahara, M.; Kambe, K.; Taguchi, K.; Saitoh, T.; Shirai, S.; Orikasa, S.; Takayama, K.; Lush, P. A.

    1990-07-01

    Biological evidence of renal arterial wall damage induced by the microjet due to shock wave-cavitation bubble interaction was demonstrated in living dog kidneys. We also intended to clarify the mechanism of renal tissue damage and the effects of different conditions of shock wave exposure (peak pressure of focused area, number of shots, exposure rate) on the renal tissue damage in comparison to stone disintegration. Disruption of arterial wall was the most remarkable histological change in the focused area of the kidneys. This lesion appeared as if the wall had been punctured by a needle. Large hematoma formation in the renal parenchym, and interstitial hemorrhage seemed to be the results of the arterial lesion. This arterial disorder also led to ischemic necrosis of the tubules surrounding the hematoma. Micro-angiographic examination of extracted kidneys also proved such arterial puncture lesions and ischemic lesions. The number of shots required for model stone disintegration was not inversely proportional to peak pressure. It decreased markedly when peak pressure was above 700 bar. Similarly thenumber of shots for hematoma formation was not inversely proportional to peak pressure, however, this decreased markedly above 500 bar. These results suggested that a hematoma could be formed under a lower peak pressure than that required for stone disintegration.

  3. Kidney Injury Molecule-1 Protects against Gα12 Activation and Tissue Damage in Renal Ischemia-Reperfusion Injury

    PubMed Central

    Ismail, Ola Z.; Zhang, Xizhong; Wei, Junjun; Haig, Aaron; Denker, Bradley M.; Suri, Rita S.; Sener, Alp; Gunaratnam, Lakshman

    2016-01-01

    Ischemic acute kidney injury is a serious untreatable condition. Activation of the G protein α12 (Gα12) subunit by reactive oxygen species is a major cause of tissue damage during renal ischemia-reperfusion injury. Kidney injury molecule-1 (KIM-1) is a transmembrane glycoprotein that is highly up-regulated during acute kidney injury, but the physiologic significance of this up-regulation is unclear. Here, we report for the first time that Kim-1 inhibits Gα12 activation and protects mice against renal ischemia-reperfusion injury. We reveal that Kim-1 physically interacts with and inhibits cellular Gα12 activation after inflammatory stimuli, including reactive oxygen species, by blocking GTP binding to Gα12. Compared with Kim-1+/+ mice, Kim-1−/− mice exhibited greater Gα12 and downstream Src activation both in primary tubular epithelial cells after in vitro stimulation with H2O2 and in whole kidneys after unilateral renal artery clamping. Finally, we show that Kim-1–deficient mice had more severe kidney dysfunction and tissue damage after bilateral renal artery clamping, compared with wild-type mice. Our results suggest that KIM-1 is an endogenous protective mechanism against renal ischemia-reperfusion injury through inhibition of Gα12. PMID:25759266

  4. Novel lnc RNA regulated by HIF-1 inhibits apoptotic cell death in the renal tubular epithelial cells under hypoxia.

    PubMed

    Mimura, Imari; Hirakawa, Yosuke; Kanki, Yasuharu; Kushida, Natsuki; Nakaki, Ryo; Suzuki, Yutaka; Tanaka, Tetsuhiro; Aburatani, Hiroyuki; Nangaku, Masaomi

    2017-04-01

    Chronic tubulointerstitial hypoxia plays an important role as the final common pathway to end-stage renal disease. HIF-1 (hypoxia-inducible factor-1) is a master transcriptional factor under hypoxia, regulating downstream target genes. Genome-wide analysis of HIF-1 binding sites using high-throughput sequencers has clarified various kinds of downstream targets and made it possible to demonstrate the novel roles of HIF-1. Our aim of this study is to identify novel HIF-1 downstream epigenetic targets which may play important roles in the kidney. Immortalized tubular cell lines (HK2; human kidney-2) and primary cultured cells (RPTEC; renal proximal tubular cell lines) were exposed to 1% hypoxia for 24-72 h. We performed RNA-seq to clarify the expression of mRNA and long non-coding RNA (lncRNA). We also examined ChIP-seq to identify HIF-1 binding sites under hypoxia. RNA-seq identified 44 lncRNAs which are up-regulated under hypoxic condition in both cells. ChIP-seq analysis demonstrated that HIF-1 also binds to the lncRNAs under hypoxia. The expression of novel lncRNA, DARS-AS1 (aspartyl-tRNA synthetase anti-sense 1), is up-regulated only under hypoxia and HIF-1 binds to its promoter region, which includes two hypoxia-responsive elements. Its expression is also up-regulated with cobalt chloride exposure, while it is not under hypoxia when HIF-1 is knocked down by siRNA To clarify the biological roles of DARS-AS1, we measured the activity of caspase 3/7 using anti-sense oligo of DARS-AS1. Knockdown of DARS-AS1 deteriorated apoptotic cell death. In conclusion, we identified the novel lncRNAs regulated by HIF-1 under hypoxia and clarified that DARS-AS1 plays an important role in inhibiting apoptotic cell death in renal tubular cells. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  5. Impact of genetic knockout of PEPT2 on cefadroxil pharmacokinetics, renal tubular reabsorption, and brain penetration in mice.

    PubMed

    Shen, Hong; Ocheltree, Scott M; Hu, Yongjun; Keep, Richard F; Smith, David E

    2007-07-01

    The aim of this study was to examine the role of PEPT2, a proton-coupled oligopeptide transporter of the SLC15 family, on the disposition of the antibiotic cefadroxil in the body, particularly the kidney and brain. Pharmacokinetic, tissue distribution, and renal clearance studies were performed in wild-type and PEPT2 null mice after intravenous bolus administration of [(3)H]cefadroxil at 1, 12.5, 50, and 100 nmol/g body weight. Studies were also performed in the absence and presence of probenecid and quinine. Cefadroxil disposition kinetics was clearly nonlinear over the dose range studied (1-100 nmol/g), which was attributed to both saturable renal tubular secretion and reabsorption of the antibiotic. After an intravenous bolus dose of 1 nmol/g cefadroxil, PEPT2 null mice exhibited a 3-fold greater total clearance and 3-fold lower systemic concentrations of drug compared with wild-type animals. Renal clearance studies further demonstrated that the renal reabsorption of cefadroxil was almost completely abolished in PEPT2 null versus wild-type mice (3% versus 70%, p < 0.001). Of the 70% of cefadroxil reabsorbed in wild-type mice, PEPT2 accounted for 95% and PEPT1 accounted for 5% of reabsorbed substrate. Tissue distribution studies indicated that PEPT2 had a dramatic effect on cefadroxil tissue exposure, especially in brain where the cerebrospinal fluid (CSF)-to-blood concentration ratio of cefadroxil was 6-fold greater in PEPT2 null mice compared with wild-type animals. These findings demonstrate that renal PEPT2 is almost entirely responsible for the reabsorption of cefadroxil in kidney and that choroid plexus PEPT2 limits the exposure of cefadroxil (and perhaps other aminocephalosporins) in CSF.

  6. Atrial Natriuretic Peptide Stimulates Dopamine Tubular Transport by Organic Cation Transporters: A Novel Mechanism to Enhance Renal Sodium Excretion

    PubMed Central

    Kouyoumdzian, Nicolás M.; Rukavina Mikusic, Natalia L.; Kravetz, María C.; Lee, Brenda M.; Carranza, Andrea; Del Mauro, Julieta S.; Pandolfo, Marcela; Gironacci, Mariela M.; Gorzalczany, Susana; Toblli, Jorge E.; Fernández, Belisario E.

    2016-01-01

    The aim of this study was to demonstrate the effects of atrial natriuretic peptide (ANP) on organic cation transporters (OCTs) expression and activity, and its consequences on dopamine urinary levels, Na+, K+-ATPase activity and renal function. Male Sprague Dawley rats were infused with isotonic saline solution during 120 minutes and randomized in nine different groups: control, pargyline plus tolcapone (P+T), ANP, dopamine (DA), D-22, DA+D-22, ANP+D-22, ANP+DA and ANP+DA+D-22. Renal functional parameters were determined and urinary dopamine concentration was quantified by HPLC. Expression of OCTs and D1-receptor in membrane preparations from renal cortex tissues were determined by western blot and Na+, K+-ATPase activity was determined using in vitro enzyme assay. 3H-DA renal uptake was determined in vitro. Compared to P+T group, ANP and dopamine infusion increased diuresis, urinary sodium and dopamine excretion significantly. These effects were more pronounced in ANP+DA group and reversed by OCTs blockade by D-22, demonstrating that OCTs are implied in ANP stimulated-DA uptake and transport in renal tissues. The activity of Na+, K+-ATPase exhibited a similar fashion when it was measured in the same experimental groups. Although OCTs and D1-receptor protein expression were not modified by ANP, OCTs-dependent-dopamine tubular uptake was increased by ANP through activation of NPR-A receptor and protein kinase G as signaling pathway. This effect was reflected by an increase in urinary dopamine excretion, natriuresis, diuresis and decreased Na+, K+-ATPase activity. OCTs represent a novel target that links the activity of ANP and dopamine together in a common mechanism to enhance their natriuretic and diuretic effects. PMID:27392042

  7. Damage analysis of CFRP-confined circular concrete-filled steel tubular columns by acoustic emission techniques

    NASA Astrophysics Data System (ADS)

    Li, Dongsheng; Chen, Zhi; Feng, Quanming; Wang, Yanlei

    2015-08-01

    Damage properties of carbon fiber-reinforced polymer (CFRP) confined circular concrete-filled steel tubular (CCFT) columns were analyzed through acoustic emission (AE) signals. AE characteristic parameters were obtained through axial compression tests. The severity of damage to CFRP-CCFT columns was estimated using the growing trend of AE accumulated energy as basis. The bearing capacity of CFRP-CCFT columns and AE accumulated energy improved as CFRP layers increased. The damage process was studied using a number of crucial AE parameters. The cracks’ mode can be differentiated through the ratio of the rise time to the waveform amplitude and through average frequency analysis. With the use of intensity signal analysis, the damage process of the CFRP-CCFT columns can be classified into three levels that represent different degrees. Based on b-value analysis, the development of the obtained cracks can be defined. Thus, identifying an initial yielding and providing early warning is possible.

  8. Galectin-3 Blockade Reduces Renal Fibrosis in Two Normotensive Experimental Models of Renal Damage

    PubMed Central

    Martinez-Martinez, Ernesto; Ibarrola, Jaime; Calvier, Laurent; Fernandez-Celis, Amaya; Leroy, Celine; Cachofeiro, Victoria; Rossignol, Patrick; Lopez-Andres, Natalia

    2016-01-01

    Background Galectin-3 (Gal-3), a β-galactoside-binding lectin, is increased in kidney injury and its pharmacological blockade reduces renal damage in acute kidney injury, hyperaldosteronism or hypertensive nephropathy. We herein investigated the effects of pharmacological Gal-3 inhibition by modified citrus pectin (MCP) in early renal damage associated with obesity and aortic stenosis (AS). Results Gal-3 was upregulated in kidneys from high fat diet (HFD) rats and in animals with partial occlusion of ascending aorta (AS). Urinary and plasma neutrophil gelatinase-associated lipocalin (NGAL) and urinary albumin were enhanced in HFD and AS rats. In kidney from obese rats, fibrotic markers (collagen, TFG-β), epithelial-mesenchymal transition molecules (α-smooth muscle actin, E-cadherin), inflammatory mediator (osteopontin) and kidney injury marker (kidney injury molecule-1) were modified. In kidney from AS rats, fibrotic markers (collagen, CTGF), epithelial-mesenchymal transition molecules (fibronectin, α-smooth muscle actin, β-catenin, E-cadherin) and kidney injury markers (NGAL, kidney injury molecule-1) were altered. Histologic observations of obese and AS rat kidneys revealed tubulointerstitial fibrosis. The pharmacological inhibition of Gal-3 with MCP normalized renal Gal-3 levels as well as functional, histological and molecular alterations in obese and AS rats. Conclusions In experimental models of mild kidney damage, the increase in renal Gal-3 expression paralleled with renal fibrosis, inflammation and damage, while these alterations were prevented by Gal-3 blockade. These data suggest that Gal-3 could be a new player in renal molecular, histological and functional alterations at early stages of kidney damage. PMID:27829066

  9. Urinary N-acetyl-beta-D-glucosaminidase and malondialdehyde as a markers of renal damage in burned patients.

    PubMed Central

    Kang, H. K.; Kim, D. K.; Lee, B. H.; Om, A. S.; Hong, J. H.; Koh, H. C.; Lee, C. H.; Shin, I. C.; Kang, J. S.

    2001-01-01

    This study was aimed to evaluate renal dysfunction during three weeks after the burn injuries in 12 patients admitted to the Hallym University Hankang Medical Center with flame burn injuries (total body surface area, 20-40%). Parameters assessed included 24-hr urine volume, blood urea nitrogen, serum creatinine, creatinine clearance, total urinary protein, urinary microalbumin, 24-hr urinary N-acetyl-beta-D-glucosaminidase (NAG) activity, and urinary malondialdehyde (MDA). Statistical analysis was performed using repeated measures ANOVA test. The 24-hr urine volume, creatinine clearance, and urinary protein significantly increased on day 3 post-burn and fell thereafter. The urine microalbumin excretion showed two peak levels on day 0 post-burn and day 3. The 24-hr urinary NAG activity significantly increased to its maximal level on day 7 post-burn and gradually fell thereafter. The urinary MDA progressively increased during 3 weeks after the burn injury. Despite recovery of general renal function through an intensive care of burn injury, renal tubular damage and lipid peroxidation of the renal tissue suggested to persist during three weeks after the burn. Therefore, a close monitoring and intensive management of renal dysfunction is necessary to prevent burn-induced acute renal failure as well as to lower mortality in patients with major burns. PMID:11641529

  10. Improved Structure and Function in Autosomal Recessive Polycystic Rat Kidneys with Renal Tubular Cell Therapy.

    PubMed

    Kelly, K J; Zhang, Jizhong; Han, Ling; Kamocka, Malgorzata; Miller, Caroline; Gattone, Vincent H; Dominguez, Jesus H

    2015-01-01

    Autosomal recessive polycystic kidney disease is a truly catastrophic monogenetic disease, causing death and end stage renal disease in neonates and children. Using PCK female rats, an orthologous model of autosomal recessive polycystic kidney disease harboring mutant Pkhd1, we tested the hypothesis that intravenous renal cell transplantation with normal Sprague Dawley male kidney cells would improve the polycystic kidney disease phenotype. Cytotherapy with renal cells expressing wild type Pkhd1 and tubulogenic serum amyloid A1 had powerful and sustained beneficial effects on renal function and structure in the polycystic kidney disease model. Donor cell engraftment and both mutant and wild type Pkhd1 were found in treated but not control PCK kidneys 15 weeks after the final cell infusion. To examine the mechanisms of global protection with a small number of transplanted cells, we tested the hypothesis that exosomes derived from normal Sprague Dawley cells can limit the cystic phenotype of PCK recipient cells. We found that renal exosomes originating from normal Sprague Dawley cells carried and transferred wild type Pkhd1 mRNA to PCK cells in vivo and in vitro and restricted cyst formation by cultured PCK cells. The results indicate that transplantation with renal cells containing wild type Pkhd1 improves renal structure and function in autosomal recessive polycystic kidney disease and may provide an intra-renal supply of normal Pkhd1 mRNA.

  11. Ibuprofen-Induced Hypokalemia and Distal Renal Tubular Acidosis: A Patient's Perceptions of Over-the-Counter Medications and Their Adverse Effects.

    PubMed

    Salter, Mark D

    2013-01-01

    We highlight a case of distal renal tubular acidosis secondary to ibuprofen and codeine use. Of particular interest in this case are the patient's perception of over-the-counter (OTC) medication use, her own OTC use prior to admission, and her knowledge of adverse reactions or side effects of these medications prior to taking them.

  12. Ibuprofen-Induced Hypokalemia and Distal Renal Tubular Acidosis: A Patient's Perceptions of Over-the-Counter Medications and Their Adverse Effects

    PubMed Central

    Salter, Mark D.

    2013-01-01

    We highlight a case of distal renal tubular acidosis secondary to ibuprofen and codeine use. Of particular interest in this case are the patient's perception of over-the-counter (OTC) medication use, her own OTC use prior to admission, and her knowledge of adverse reactions or side effects of these medications prior to taking them. PMID:24829833

  13. Characterisation of the expression of the Renin-Angiotensin system in primary and immortalised human renal proximal tubular cells.

    PubMed

    Shalamanova, Liliana; Wilkinson, Mark C; McArdle, Frank; Jackson, Malcolm J; Rustom, Rana

    2010-01-01

    Angiotensin II (AngII) is pivotal in the pathogenesis of progressive kidney disease. We have recently shown that AngII induced an increase in markers of oxidative stress, adaptive responses and upregulated stress-related gene expression in immortalised human proximal tubular (HK-2) cells. However, these observed effects of AngII were not mediated solely via AngII type 1 receptor (ATR1). Both HK-2 cells and primary human renal proximal tubular cells (RPTEC) are useful tools to investigate the renin-angiotensin system (RAS), but data on the local expression of the RAS in these cells remain limited. We therefore characterised RAS expression in RPTEC and HK-2 cells. The mRNA and protein expression of RAS in RPTEC and HK-2 cells was examined by RT-PCR, Western blotting and immunoprecipitation. In both cell lines, mRNA for angiotensin-converting enzyme (ACE) and mRNA and protein expression for angiotensinogen, renin, ACE2, ATR1 and ATR4 were detected. Candesartan, a specific ATR1 blocker, effectively blocked the expression of 80% of the stress-related genes that were upregulated in HK-2 cells following exposure to AngII. These data support a role for AngII in mediating oxidative stress via other receptor types stimulated by AngII and confirm that it is possible to investigate ATR4 pathways of potential injury in RPTEC. Copyright © 2010 S. Karger AG, Basel.

  14. Calcium Dobesilate Prevents Diabetic Kidney Disease by Decreasing Bim and Inhibiting Apoptosis of Renal Proximal Tubular Epithelial Cells.

    PubMed

    Cai, Tian; Wu, Xiao-Yun; Zhang, Xiao-Qian; Shang, Hong-Xia; Zhang, Zhong-Wen; Liao, Lin; Dong, Jian-Jun

    2017-04-01

    Apoptosis of renal proximal tubular epithelial cells (PTECs) plays a vital role in the pathogenesis and progression of diabetic kidney disease (DKD). Calcium dobesilate is a vascular protective compound used for treatment of diabetic retinopathy and chronic venous insufficiency. The aim of this study was to determine whether calcium dobesilate can protect PTECs from glucose-induced apoptosis and the potential mechanism of this effect. It is indicated that high glucose promoted abnormal apoptosis of HK2 cells, which was inhibited by treatment of calcium dobesilate, while Bim expression decreased in response to calcium dobesilate in high-glucose-treated HK2 cells. These findings confirmed the therapeutic effects of calcium dobesilate on DKD and emphasized the importance of it as a potentially crucial drug in treatment of DKD.

  15. WNT/β-Catenin Signaling Is Required for Integration of CD24+ Renal Progenitor Cells into Glycerol-Damaged Adult Renal Tubules

    PubMed Central

    Zhang, Zhao; Iglesias, Diana M.; Corsini, Rachel; Chu, LeeLee; Goodyer, Paul

    2015-01-01

    During development, nephron progenitor cells (NPC) are induced to differentiate by WNT9b signals from the ureteric bud. Although nephrogenesis ends in the perinatal period, acute kidney injury (AKI) elicits repopulation of damaged nephrons. Interestingly, embryonic NPC infused into adult mice with AKI are incorporated into regenerating tubules. Since WNT/β-catenin signaling is crucial for primary nephrogenesis, we reasoned that it might also be needed for the endogenous repair mechanism and for integration of exogenous NPC. When we examined glycerol-induced AKI in adult mice bearing a β-catenin/TCF reporter transgene, endogenous tubular cells reexpressed the NPC marker, CD24, and showed widespread β-catenin/TCF signaling. We isolated CD24+ cells from E15 kidneys of mice with the canonical WNT signaling reporter. 40% of cells responded to WNT3a in vitro and when infused into glycerol-injured adult, the cells exhibited β-catenin/TCF reporter activity when integrated into damaged tubules. When embryonic CD24+ cells were treated with a β-catenin/TCF pathway inhibitor (IWR-1) prior to infusion into glycerol-injured mice, tubular integration of cells was sharply reduced. Thus, the endogenous canonical β-catenin/TCF pathway is reactivated during recovery from AKI and is required for integration of exogenous embryonic renal progenitor cells into damaged tubules. These events appear to recapitulate the WNT-dependent inductive process which drives primary nephrogenesis. PMID:26089915

  16. Ca(2+) movement and apoptosis induced by deltamethrin in Madin-Darby canine kidney canine renal tubular cells.

    PubMed

    Liu, Fang-Jin; Chou, Chiang-Ting; Cheng, Jin Shiung; Chang, Hong-Tai; Liang, Wei-Zhe; Kuo, Chun-Chi; Kuo, Soong-Yu; Kuo, Daih-Huang; Shieh, Pochuen; Chang, Fang-Rong; Jan, Chung-Ren

    2015-01-01

    This study explored the effect of deltamethrin, a pesticide, on free Ca(2+) concentration [Ca(2+)]i, viability, and apoptosis in Madin-Darby canine kidney (MDCK) canine renal tubular cells. Deltamethrin at concentrations between 10μM and 40μM evoked [Ca(2+)]i rises in a concentration-dependent manner. The Ca(2+) entry was inhibited by nifedipine, econazole, phorbol 12-myristate 13-acetate, and SKF96365. Treatment with the endoplasmic reticulum Ca(2+) pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) in a Ca(2+)-free medium abolished deltamethrin-induced [Ca(2+)]i rise. Treatment with deltamethrin also abolished BHQ-induced [Ca(2+)]i rise. Inhibition of phospholipase C (PLC) activity with U73122 abolished deltamethrin-evoked [Ca(2+)]i rise. Deltamethrin killed cells at 30-60μM in a concentration-dependent manner. The cytotoxic effect of deltamethrin was not reversed by prechelating cytosolic Ca(2+) with the acetoxymethyl ester of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Annexin V/propidium iodide staining data suggest that 30-50μM deltamethrin induced apoptosis. Together, in MDCK renal tubular cells, deltamethrin induced [Ca(2+)]i rises that involved Ca(2+) entry through protein kinase C-mediated store-operated Ca(2+) channels, and PLC-dependent Ca(2+) release from the endoplasmic reticulum. Deltamethrin also induced Ca(2+)-independent cell death that might involve apoptosis. Copyright © 2014. Published by Elsevier Taiwan.

  17. Malondialdehyde, antioxidant enzymes, and renal tubular functions in children with iron deficiency or iron-deficiency anemia.

    PubMed

    Altun, Demet; Kurekci, Ahmet Emin; Gursel, Orhan; Hacıhamdioglu, Duygu Ovunc; Kurt, Ismail; Aydın, Ahmet; Ozcan, Okan

    2014-10-01

    We aimed to investigate the effects of iron deficiency (ID) or iron-deficiency anemia (IDA) on oxidative stress and renal tubular functions before and after treatment of children. A total of 30 children with a diagnosis of IDA constituted the IDA group and 32 children with a diagnosis of ID constituted the ID group. Control group consisted 38 age-matched children. Serum ferritin, soluble transferrin receptor (sTfR), serum, and urinary sodium (Na), potassium (K), calcium (Ca), phosphorus (P), creatinine (Cr), uric acid (UA), urinary N-acetyl-β-D-glucosaminidase (NAG) levels, and intra-erythrocyte malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels were measured before and after iron therapy in the IDA and ID groups, whereas it was studied once in the control group. We have divided the study group in groups according to age (infants <2 years, children 3-9 years, and adolescents 10-15 years). Patients with IDA (infant, adolescent) and ID (infant, children, and adolescent) had a significantly high level of MDA in post-treatment period in comparison to those of healthy control. Patients with IDA (children, adolescent) and ID (infant, children) had a significantly high level of pre-treatment GSH-Px than controls. Post-treatment SOD was lower in IDA (children and adolescent) groups than control and post-treatment CAT was lower in IDA and ID (adolescent) groups than control. These findings show that ferrous sulfate used in the treatment of ID or IDA could lead to oxidative stress; however, a marked deterioration of in proximal renal tubular functions was not seen.

  18. T-bet-positive mononuclear cell infiltration is associated with transplant glomerulopathy and interstitial fibrosis and tubular atrophy in renal allograft recipients.

    PubMed

    Yadav, Brijesh; Prasad, Narayan; Agrawal, Vinita; Jain, Manoj; Agarwal, Vikas; Jaiswal, Akhilesh; Bhadauria, Dharmendra; Sharma, R K; Gupta, Amit

    2015-04-01

    We aimed to study the role of T-bet-positive mononuclear cell infiltration in different compartments of kidney graft tissues in patients with chronic transplant glomerulopathy, interstitial fibrosis and tubular atrophy, and stable graft function. There were 80 living-related renal transplant recipients included (chronic transplant glomerulopathy, n = 28; interstitial fibrosis and tubular atrophy, n = 28; stable graft function, n = 24). Histologic characteristics and scoring for peritubular capillaritis, glomerulitis, interstitial fibrosis and tubular atrophy, and intimal arteritis were performed according to Banff 2007 classification and compared between the groups. Immunohistologic staining was performed for transcription factor T-bet, T-bet mononuclear cells were counted, and T-bet infiltration score was compared between groups. Patients in different groups had similar clinical profiles and human leukocyte antigen mismatches, except the groups differed in serum creatinine and proteinuria. The prevalence and scoring of peritubular capillaritis and glomerulitis were significantly higher in chronic transplant glomerulopathy than interstitial fibrosis and tubular atrophy (P = .001) and stable graft function (P < .001). Tubulitis was observed in 6 patients (21.4%) with chronic transplant glomerulopathy but no patients with interstitial fibrosis and tubular atrophy. The C4d/donor-specific antibody was positive in 100% patients with chronic transplant glomerulopathy, 0% patients with interstitial fibrosis and tubular atrophy, and 4.1 % patients with stable graft function. Interstitial fibrosis and tubular atrophy was seen in 100% patients who had interstitial fibrosis and tubular atrophy; in patients who had chronic transplant glomerulopathy, 24 patients (85.7%) had interstitial fibrosis and 78.5% patients had tubular atrophy. The degree and severity of T-bet-positive cell infiltration were significantly higher in chronic transplant glomerulopathy than interstitial

  19. Expression of pro- and antifibrotic genes in protocol biopsies from renal allografts with interstitial fibrosis and tubular atrophy.

    PubMed

    Mengel, M; Bock, O; Priess, M; Haller, H; Kreipe, H; Gwinner, W

    2008-06-01

    Better understanding of early onset of interstitial fibrosis and tubular atrophy (IF/TA), as the morphological surrogate of renal allograft deterioration might improve outcome after renal transplantation. We quantified mRNA expression of 3 profibrotic (transforming growth factor-beta (TGF-beta), tissue transglutaminase (tTG), tissue inhibitor of matrix metalloproteases (TIMP-1)) and 1 antifibrotic (matrix metalloprotease-2 (MMP-2)) molecule in protocol biopsies from renal allografts. From 107 transplants, two sequential protocol biopsies (6 weeks and 6 months) were analyzed. We evaluated a control group showing no IF/TA in both biopsies (n = 65) and a IF/TA group developing IF/TA at 6 months (n = 42). Expression data were correlated with clinical and histological risk factors for IF/TA and allograft function. The expression of the genes correlated strongly with each other, particularly the profibrotic genes and in patients who developed IF/TA. Analyzing protocol biopsies from stable grafts, not all patients in both groups showed increased gene expression. In patients with increased gene expression a significantly higher tTG expression (matrix stabilization) at 6 weeks and a significantly lower MMP-2 expression (failure in matrix degradation) at 6 months were observed in the IFTA group compared to controls. Multivariate logistic regression revealed donor age positively and TIMP-1 expression at 6 weeks inversely correlated with IF/TA at 6 months. We conclude that a disturbance in the equilibrium of pro- and antifibrotic pathways is decisive for early onset of IF/TA in renal allografts: insufficient degradation of exaggerated matrix production apparently changes the balance in the direction of IF/TA.

  20. Autoradiographic study of dna synthesis in renal tubular epithelial cells of albino rats with mercuric chloride nephrosis

    SciTech Connect

    Andreev, V.P.; Pal'tsyn, A.A.

    1986-04-01

    Data on the character of reproduction of the renal epithelium, damaged by HgCl/sub 2/, have been obtained by /sup 3/H-thymidine autoradiography. In the investigation presented in this paper, to evaluate the structure and DNA-synthetic activity of epithelial cells damaged by HgCl/sub 2/ it was decided to use semithin sections, cut from blocks embedded for electron microscopy, since autoradiography with paraffin sections has inadequate resolving power for the detailed study of the structure of damaged nephrocytes and the character of distribution of radioactive label in them. Analysis of the autoradiographs showed that 72 h after injection of HgCl/sub 2/, nephrocyte nuclei labeled with /sup 3/H-thymidine were found in damaged segments of the proximal tubule of the nephron much more often than in intact segments. Under the conditions of necrotic nephrosis induced by HgCl/sub 2/, damaged epithelial cells can be restored through intracellular regeneration.

  1. Exaggerated natriuretic response to isotonic volume expansion in hypertensive renal transplant recipients: evaluation of proximal and distal tubular reabsorption by simultaneous determination of renal plasma clearance of lithium and 51Cr-EDTA.

    PubMed

    Nielsen, A H; Knudsen, F; Danielsen, H; Pedersen, E B; Fjeldborg, P; Madsen, M; Brøchner-Mortensen, J; Kornerup, H J

    1987-02-01

    In fourteen hypertensive and fourteen normotensive renal transplant recipients, and in a group of thirteen healthy controls, changes in natriuresis, glomerular filtration rate (GFR), and tubular reabsorption of sodium were determined in relation to intravenous infusion of 2 mmol isotonic sodium chloride per kg body weight. An exaggerated natriuresis was demonstrated in the hypertensive renal transplant recipients. This new finding indicates that the augmented natriuresis following plasma volume expansion, which is a characteristic finding in subjects with arterial hypertension, is not mediated by the renal nerves. Investigation of the tubular reabsorption rates of sodium by simultaneous determination of the renal clearance of 51Cr-EDTA and lithium showed that in the hypertensives the changes in tubular handling of sodium were different from those registered in the normotensive subjects. The increased sodium excretion in the hypertensive renal transplant recipients was caused by an increased output of sodium from the proximal tubules which was not fully compensated for by an increased distal reabsorption. Whether this increased delivery of sodium to the distal segments was caused by changes in GFR or in the proximal tubular reabsorption of sodium could not be clarified in the present study and warrants further investigations.

  2. Using Tc-99m DMSA renal cortex scan to detect renal damage in women with type 2 diabetes.

    PubMed

    Wu, Hsi-Chin; Chang, Chao-Hsiang; Lai, Ming-May; Lin, Cheng-Chieh; Lee, Cheng-Chun; Kao, Albert

    2003-01-01

    Women with diabetes mellitus (DM) have urinary tract infection (UTI) more often than women without DM. It is unknown, however, what the prevalence and type of renal damage due to UTI is in these women. Therefore, in this study, we compared type 2 DM women with or without UTI history for the prevalence and type of renal damage by technetium-99m dimercapto-succinic acid (Tc-99m DMSA) renal scan. A total of 128 type 2 DM women with or without UTI history received Tc-99m DMSA renal scan were included in this study. The patients were separated into three groups: (1) 43 patients without UTI history, (2) 42 patients with only lower UTI (cystitis) history and (3) 43 patients with upper UTI (pyelonephritis) history. The renal scan findings were separated into three types: (A) normal, (B) inflammation and (C) scar. The 31.9% (50/128) of type 2 DM patients had renal damages. Group 1 patients had a significantly lower prevalence of renal damages including inflammation and scar as compared to Groups 2 and 3 patients. In addition, the prevalence of renal damage was significantly higher in Group 3 than in Group 2 patients. Renal scars only were visualized in Group 3 patients. However, other clinical data were not statistically different among the three group patients. Type 2 DM women with UTI history, especially if they had upper UTI have a significantly higher prevalence of renal damage than in those without UTI.

  3. Does Renal Tubular Injury-Induced Local Tissue Hypoxia Involve Post-Transplantation Erythrocytosis?

    PubMed

    Unal, A; Ata, S; Karakurkcu, C; Ciraci, M Z; Kocyigit, I; Sipahioglu, M H; B Tokgoz; Oymak, O

    2017-10-01

    The pathogenesis of post-transplantation erythrocytosis (PTE) is not well understood and appears to be multifactorial. Our hypothesis in this study was that several factors, including toxicity of calcineurin inhibitor, immunologic factors, and chronic allograft nephropathy, can trigger local tissue hypoxia in peritubular interstitium, which is where production of erythropoietin (EPO) takes place. This local interstitial tissue hypoxia can cause an increase in renal EPO production, which induces the development of PTE. This cross-sectional study included 15 renal transplant recipients, in whom polycythemia developed after kidney transplantation, with elevated hematocrit level to >51%. Forty-eight age- and gender-matched renal transplant recipients with normal hematocrit level were included as the renal transplant control group. In addition, 13 age- and gender-matched healthy subjects were also included as the healthy control group. We used urine hypoxia-inducible factor-2 alpha (HIF-2α) levels to evaluate whether there is local tissue hypoxia in renal allograft. HIF-2α levels were measured by double antibody sandwich enzyme-linked immunosorbent assay (ELISA). Serum EPO and insulin-like growth factor-1 (IGF-1) levels were also measured. HIF-2α levels were significantly lower in the polycythemia group than the other two groups, but there was no significant difference between the healthy control group and the renal transplant control group with regard to HIF-2α levels. There was no significant difference among the 3 study groups in terms of levels of serum EPO and IGF-1. Local tissue hypoxia in renal allograft does not seem to play an important role in the development of PTE. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Effects of shiga toxin 2 on cellular regeneration mechanisms in primary and three-dimensional cultures of human renal tubular epithelial cells.

    PubMed

    Márquez, Laura B; Araoz, Alicia; Repetto, Horacio A; Ibarra, Fernando R; Silberstein, Claudia

    2016-10-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) causes post-diarrheal Hemolytic Uremic Syndrome (HUS), which is one of the most common causes of acute renal failure in children in Argentine. The aim of the present work was to study the effects of Shiga toxin type 2 (Stx2) on regenerative mechanisms of primary cultures of human cortical renal tubular epithelial cells (HRTEC) and three-dimensional (3D) cultures of HRTEC. Primary cultures of HRTEC were able to develop tubular structures when grown in matrigel, which showed epithelial cells surrounding a central lumen resembling the original renal tubules. Exposure to Stx2 inhibited tubulogenesis in 3D-HRTEC cultures. Moreover, a significant increase in apoptosis, and decrease in cell proliferation was observed in tubular structures of 3D-HRTEC exposed to Stx2. A significant reduction in cell migration and vimentin expression levels was observed in HRTEC primary cultures exposed to Stx2, demonstrating that the holotoxin affected HRTEC dedifferentiation. Furthermore, a decreased number of cells expressing CD133 progenitor marker was found in HRTEC cultures treated with Stx2. The CD133 positive cells also expressed the Stx receptor globotriaosylceramide, which may explain their sensitivity to Stx2. In conclusion, Stx2 affects the regenerative processes of human renal tubular epithelial cells in vitro, by inhibiting cell dedifferentiation mechanisms, as well as tubules restoration. The development of 3D-HRTEC cultures that resemble original human renal proximal tubules is a novel in vitro model to study renal epithelial repair mechanisms after injury.

  5. Endocytotic Uptake of Zoledronic Acid by Tubular Cells May Explain Its Renal Effects in Cancer Patients Receiving High Doses of the Compound

    PubMed Central

    Verhulst, Anja; Sun, Shuting; McKenna, Charles E.; D’Haese, Patrick C.

    2015-01-01

    Zoledronic acid, a highly potent nitrogen-containing bisphosphonate used for the treatment of pathological bone loss, is excreted unmetabolized via the kidney if not bound to the bone. In cancer patients receiving high doses of the compound renal excretion may be associated with acute tubular necrosis. The question of how zoledronic acid is internalized by renal tubular cells has not been answered until now. In the current work, using a primary human tubular cell culture system, the pathway of cellular uptake of zoledronic acid (fluorescently/radiolabeled) and its cytotoxicity were investigated. Previous studies in our laboratory have shown that this primary cell culture model consistently mimics the physiological characteristics of molecular uptake/transport of the epithelium in vivo. Zoledronic acid was found to be taken up by tubular cells via fluid-phase-endocytosis (from apical and basolateral side) as evidenced by its co-localization with dextran. Cellular uptake and the resulting intracellular level was twice as high from the apical side compared to the basolateral side. Furthermore, the intracellular zoledronic acid level was found to be dependent on the administered concentration and not saturable. Cytotoxic effects however, were only seen at higher administration doses and/or after longer incubation times. Although zoledronic acid is taken up by tubular cells, no net tubular transport could be measured. It is concluded that fluid-phase-endocytosis of zoledronic acid and cellular accumulation at high doses may be responsible for the acute tubular necrosis observed in some cancer patients receiving high doses of the compound. PMID:25756736

  6. L-Carnitine Protects Renal Tubular Cells Against Calcium Oxalate Monohydrate Crystals Adhesion Through Preventing Cells From Dedifferentiation.

    PubMed

    Li, Shujue; Wu, Wenqi; Wu, Wenzheng; Duan, Xiaolu; Kong, Zhenzhen; Zeng, Guohua

    2016-01-01

    The interactions between calcium oxalate monohydrate (COM) crystals and renal tubular epithelial cells are important for renal stone formation but still unclear. This study aimed to investigate changes of epithelial cell phenotype after COM attachment and whether L-carnitine could protect cells against subsequent COM crystals adhesion. Cultured MDCK cells were employed and E-cadherin and Vimentin were used as markers to estimate the differentiate state. AlexaFluor-488-tagged COM crystals were used in crystals adhesion experiment to distinguish from the previous COM attachment, and adhesive crystals were counted under fluorescence microscope, which were also dissolved and the calcium concentration was assessed by flame atomic absorption spectrophotometry. Dedifferentiated MDCK cells induced by transforming growth factor β1 (TGF-β1) shown higher affinity to COM crystals. After exposure to COM for 48 hours, cell dedifferentiation were observed and more subsequent COM crystals could bind onto, mediated by Akt/GSK-3β/Snail signaling. L-carnitine attenuated this signaling, resulted in inhibition of cell dedifferentiation and reduction of subsequent COM crystals adhesion. COM attachment promotes subsequent COM crystals adhesion, by inducing cell dedifferentiation via Akt/GSK-3β/Snail signaling. L-carnitine partially abolishes cell dedifferentiation and resists COM crystals adhesion. L-carnitine, may be used as a potential therapeutic strategy against recurrence of urolithiasis. © 2016 The Author(s) Published by S. Karger AG, Basel.

  7. Endolymphatic sac enlargement in a girl with a novel mutation for distal renal tubular acidosis and severe deafness.

    PubMed

    Nikki, Rink; Martin, Bitzan; Gus, O'Gorman; Mato, Nagel; Elena, Torban; Paul, Goodyer

    2012-01-01

    Hereditary distal renal tubular acidosis (dRTA) is caused by mutations of genes encoding subunits of the H(+)-ATPase (ATP6V0A4 and ATP6V1B1) expressed in α-intercalated cells of the distal renal tubule and in the cochlea. We report on a 2-year-old girl with distal RTA and profound speech delay which was initially misdiagnosed as autism. Genetic analysis showed compound heterozygous mutations with one known and one novel mutation of the ATP6V1B1 gene; cerebral magnetic resonance imaging (MRI) revealed bilateral enlargement of the endolymphatic sacs of the inner ear. With improved cooperation, audiometric testing showed that hearing loss was most profound on the right, where endolymphatic sac enlargement was greatest, demonstrating a clear link between the degree of deafness and the degree of inner ear abnormality. This case indicates the value of MRI for diagnosis of inner ear involvement in very young children with distal RTA. Although citrate therapy quickly corrects the acidosis and restores growth, early diagnosis of deafness is crucial so that hearing aids can be used to assist acquisition of speech and to provide enough auditory nerve stimulation to assure the affected infants remain candidates for cochlear implantation.

  8. Proximal renal tubular acidosis mediated by mutations in NBCe1-A: unraveling the transporter's structure-functional properties

    PubMed Central

    Kurtz, Ira; Zhu, Quansheng

    2013-01-01

    NBCe1 belongs to the SLC4 family of base transporting membrane proteins that plays a significant role in renal, extrarenal, and systemic acid-base homeostasis. Recent progress has been made in characterizing the structure-function properties of NBCe1 (encoded by the SLC4A4 gene), and those factors that regulate its function. In the kidney, the NBCe1-A variant that is expressed on the basolateral membrane of proximal tubule is the key transporter responsible for overall transepithelial bicarbonate absorption in this nephron segment. NBCe1 mutations impair transepithelial bicarbonate absorption causing the syndrome of proximal renal tubular acidosis (pRTA). Studies of naturally occurring NBCe1 mutant proteins in heterologous expression systems have been very helpful in elucidation the structure-functional properties of the transporter. NBCe1 mutations are now known to cause pRTA by various mechanisms including the alteration of the transporter function (substrate ion interaction, electrogenicity), abnormal processing to the plasma membrane, and a perturbation in its structural properties. The elucidation of how NBCe1 mutations cause pRTA in addition to the recent studies which have provided further insight into the topology of the transporter have played an important role in uncovering its critically important structural-function properties. PMID:24391589

  9. Hypoxia reduces constitutive and TNF-{alpha}-induced expression of monocyte chemoattractant protein-1 in human proximal renal tubular cells

    SciTech Connect

    Li Xuan; Kimura, Hideki . E-mail: hkimura@fmsrsa.fukui-med.ac.jp; Hirota, Kiichi; Sugimoto, Hidehiro; Yoshida, Haruyoshi

    2005-10-07

    Chronic hypoxia has been reported to be associated with macrophage infiltration in progressive forms of kidney disease. Here, we investigated the regulatory effects of hypoxia on constitutive and TNF-{alpha}-stimulated expression of monocyte chemoattractant protein-1 (MCP-1) in cultured human proximal renal tubular cells (HPTECs). Hypoxia reduced constitutive MCP-1 expression at the mRNA and protein levels in a time-dependent fashion for up to 48 h. Hypoxia also inhibited MCP-1 up-regulation by TNF-{alpha}. Treatment with actinomycin D showed that hypoxic down-regulation of MCP-1 expression resulted mainly from a decrease in the transcription but not the mRNA stability. Immunoblot and immunofluorescence analyses revealed that treatment with hypoxia or an iron chelator, desferrioxamine, induced nuclear accumulation of hypoxia-inducible factor-1{alpha} (HIF-1{alpha}) in HPTECs. Desferrioxamine mimicked hypoxia in the reduction of MCP-1 expression. However, overexpression of a dominant negative form of HIF-1{alpha} did not abolish the hypoxia-induced reduction of MCP-1 expression in HPTECs. These results suggest that hypoxia is an important negative regulator of monocyte chemotaxis to the renal inflamed interstitium, by reducing MCP-1 expression partly via hypoxia-activated signals other than the HIF-1 pathway.

  10. Serum level of proximal renal tubular epithelial cell-binding immunoglobulin G in patients with lupus nephritis.

    PubMed

    Yap, D Y H; Yung, S; Zhang, Q; Tang, C; Chan, T M

    2016-01-01

    In vitro data showed that immunoglobulin G (IgG) from lupus nephritis (LN) patients could bind to proximal renal tubular epithelial cells (PTEC), but the clinical relevance of such binding remained unclear. Binding of IgG and subclasses to PTEC was measured by cellular ELISA (expressed as OD index) in 189 serial serum samples from 23 Class III/IV ± V LN patients who had repeated renal flares (48 during renal flares, 141 during low level disease activity (LLDA)), and compared with 64 patients with non-lupus glomerular diseases (NLGD) and 23 healthy individuals. Total IgG PTEC-binding index was 0.34 ± 0.16, 0.29 ± 0.16, 0.62 ± 0.27 and 0.83 ± 0.38 in healthy controls, NLGD, LN patients during LLDA, and LN patients during nephritic flare, respectively (p < 0.001, LLDA vs. renal flare; p < 0.001, healthy controls or NLGD vs. LN during LLDA or renal flare). PTEC-binding index for IgG1 was 0.09 ± 0.05, 0.16 ± 0.12, 0.44 ± 0.34 and 0.71 ± 0.46 for the corresponding groups (p < 0.001, LLDA vs. renal flare; p < 0.001, healthy controls or NLGD vs. LN during LLDA or renal flare). Sixteen of 48 episodes (33.3%) of nephritic flare showed persistent PTEC-binding IgG seropositivity for more than 9.4 ± 3.1 months, despite clinical response to immunosuppressive treatment. Total IgG and IgG1 PTEC-binding correlated with anti-dsDNA level (r = 0.34 and 0.52, respectively, p < 0.001 for both), and inversely with C3 level (r = -0.26 and -0.50, respectively, p = 0.002 and<0.001). Sensitivity/specificity of PTEC-binding index in detecting renal flares was 45.8%/80.1% for total IgG (ROC AUC 0.630, p = 0.007) and 87.5%/35.5% for IgG1 (ROC AUC 0.615, p = 0.018). IgG1 PTEC-binding index correlated with tubulo-interstitial inflammation score in renal biopsy from corresponding patients. Our data suggested that total IgG and IgG1 PTEC-binding index in serum of LN patients correlate with serological activity, and in combination could predict renal flares. The correlation between IgG1

  11. An experimental renal acidification defect in patients with hereditary fructose intolerance. II. Its distinction from classic renal tubular acidosis; its resemblance to the renal acidification defect associated with the Fanconi syndrome of children with cystinosis.

    PubMed

    Morris, R C

    1968-07-01

    In adult patients with hereditary fructose intolerance (HFI) fructose induces a renal acidification defect characterized by (a) a 20-30% reduction in tubular reabsorption of bicarbonate (T HCO(3) (-)) at plasma bicarbonate concentrations ranging from 21-31 mEq/liter, (b) a maximal tubular reabsorption of bicarbonate (Tm HCO(3) (-)) of approximately 1.9 mEq/100 ml of glomerular filtrate, (c) disappearance of bicarbonaturia at plasma bicarbonate concentrations less than 15 mEq/liter, and (d) during moderately severe degrees of acidosis, a sustained capacity to maintain urinary pH at normal minima and to excrete acid at normal rates. In physiologic distinction from this defect, the renal acidification defect of patients with classic renal tubular acidosis is characterized by (a) just less than complete tubular reabsorption of bicarbonate at plasma bicarbonate concentrations of 26 mEq/liter or less, (b) a normal Tm HCO(3) (-) of approximately 2.8 mEq/100 ml of glomerular filtrate, and (c) during acidosis of an even severe degree, a quantitatively trivial bicarbonaturia, as well as (d) a urinary pH of greater than 6. That the fructose-induced renal acidification defect involves a reduced H(+) secretory capacity of the proximal nephron is supported by the magnitude of the reduction in T HCO(3) (-) (20-30%) and the simultaneous occurrence and the persistence throughout administration of fructose of impaired tubular reabsorption of phosphate, alpha amino nitrogen and uric acid.A reduced H(+) secretory capacity of the proximal nephron also appears operative in two unrelated children with hyperchloremic acidosis, Fanconi's syndrome, and cystinosis. In both, T HCO(3) (-) was reduced 20-30% at plasma bicarbonate concentrations ranging from 20-30 mEq/liter. The bicarbonaturia disappeared at plasma bicarbonate concentrations ranging from 15-18 mEq/liter, and during moderate degrees of acidosis, urinary pH decreased to less than 6, and the excretion rate of acid was normal.

  12. Ketamine Increases Permeability and Alters Epithelial Phenotype of Renal Distal Tubular Cells via a GSK-3β-Dependent Mechanism.

    PubMed

    Shyu, Hsin-Yi; Ko, Chun-Jung; Luo, Yu-Chen; Lin, Hsin-Ying; Wu, Shang-Ru; Lan, Shao-Wei; Cheng, Tai-Shan; Hu, Shih-Hsiung; Lee, Ming-Shyue

    2016-04-01

    Ketamine, a dissociative anesthetic, is misused and abused worldwide as an illegal recreational drug. In addition to its neuropathic toxicity, ketamine abuse has numerous effects, including renal failure; however, the underlying mechanism is poorly understood. The process called epithelial phenotypic changes (EPCs) causes the loss of cell-cell adhesion and cell polarity in renal diseases, as well as the acquisition of migratory and invasive properties. Madin-Darby canine kidney cells, an in vitro cell model, were subjected to experimental manipulation to investigate whether ketamine could promote EPCs. Our data showed that ketamine dramatically decreased transepithelial electrical resistance and increased paracellular permeability and junction disruption, which were coupled to decreased levels of apical junctional proteins (ZO-1, occludin, and E-cadherin). Consistent with the downregulation of epithelial markers, the mesenchymal markers N-cadherin, fibronectin, and vimentin were markedly upregulated following ketamine stimulation. Of the E-cadherin repressor complexes tested, the mRNA levels of Snail, Slug, Twist, and ZEB1 were elevated. Moreover, ketamine significantly enhanced migration and invasion. Ketamine-mediated changes were at least partly caused by the inhibition of GSK-3β activity through Ser-9 phosphorylation by the PI3K/Akt pathway. Inhibiting PI3K/Akt with LY294002 reactivated GSK-3β and suppressed ketamine-enhanced permeability, EPCs, and motility. These findings were recapitulated by the inactivation of GSK-3β using the inhibitor 3F8. Taken together, these results provide evidence that ketamine induces renal distal tubular EPCs through the downregulation of several junction proteins, the upregulation of mesenchymal markers, the activation of Akt, and the inactivation of GSK-3β. © 2015 Wiley Periodicals, Inc.

  13. Impaired tubular excretory function as a late renal side effect of chemotherapy in children.

    PubMed

    Kakihara, Toshio; Imai, Chihaya; Hotta, Hiromitsu; Ikarashi, Yukie; Tanaka, Atsushi; Uchiyama, Makoto

    2003-03-01

    Renal drug excretion is variously influenced by nephrotoxic drugs. This study was designed to evaluate renal function as a late renal side effects in children receiving combination chemotherapy for malignancy. Follow-up studies of 30 newly diagnosed patients were performed a median of 12 months after completion of chemotherapy. The glomerular filtration rate (GFR) was measured using sodium thiosulfate. The following were also assessed: urinary high-molecular-weight fraction (urinary albumin/urinary creatinine ratio); para-aminohippurate (PAH) clearance; urinary low-molecular-weight fraction (urinary beta2-microglobulin/urinary creatinine ratio); and routine serum and urinary parameters. Serum and urinary electrolytes were normal in most patients. GFR was low in four patients (13%). Urinary high-molecular-weight fraction was elevated in two patients. Urinary low-molecular-weight fraction was elevated in one patient. PAH clearance was below the referenced normal value in 73% of the patients. This report demonstrates decreased PAH clearance as a late renal side effect of chemotherapy and suggests disturbed function of the organic anion transport system. The unexpected high serum concentration of drugs excreted through the organic anion transport system may induce severe side effects. Elucidation of the mechanism and clinical relevance of decreased PAH clearance is warranted.

  14. Cre-mediated reversible immortalization of human renal proximal tubular epithelial cells.

    PubMed

    Kowolik, Claudia M; Liang, Shujian; Yu, Ying; Yee, Jiing-Kuan

    2004-08-05

    Primary human renal proximal tubule epithelial cells (RPTECs) are of limited use for basic research and for clinical applications due to their limited lifespan in culture. Here we used two lentivirus vectors carrying the human telomerase (hTERT) and the SV40T antigen (Tag) flanked by loxP sites to reversibly immortalize RPTECs. Transduced RPTEC clones continued to proliferate while retaining biochemical and functional characteristics of primary cells. The clones exhibited contact-inhibited, anchorage- and growth factor-dependent growth and did not form tumors in nude mice, suggesting that the cells were not transformed. Transient Cre expression in these cells led to efficient proviral deletion, upregulation of some renal specific activities, and decreased growth rates. Ultimately, the cells underwent replicative senescence, indicating intact cell cycle control. Thus, reversible immortalization allows the expansion of human RPTECs, leading to large production of RPTECs that retain most tissue-specific properties.

  15. Functional characteristics of the renal tubular secretion of amprolium, a quaternary organic base.

    PubMed

    Beyer, K H; Gelarden, R T

    1975-11-01

    Amprolium [1-(4-amino-2-propyl-5-pyrimidinemethyl)-2-methyl-pyridinium chloride hydrochloridel is a basic (quaternary) organic compound. At very low plasma concentration, it is cleared by the kidney at a rate approximating renal plasma flow in the dog. Its renal clearance is not depressed by organic acids (p-aminohippurate or probenecid) but is reduced by the quaternary base, mepiperphenidol. Acetate and pantothenate may influence the clearance of amprolium but, if this is the case, the effect is less than for p-aminohippurate. Its clearance is depressed as urinary pH is increased. The clearance of amprolium was not altered over a substantial range in urine flow at either high or low urinary pH.

  16. Antioxidant properties of repaglinide and its protections against cyclosporine A-induced renal tubular injury

    PubMed Central

    Li, Dao; Li, Jin; Li, Hui; Wu, Qiong; Li, Qi-Xiong

    2016-01-01

    Objective(s): Repaglinide (RG) is an antihyperglycemic agent used for the treatment of non-insulin-dependent diabetes mellitus. It has a good safety and efficacy profile in diabetic patients with complications in renal impairment and is an appropriate treatment choice, even for individuals with more severe degrees of renal malfunctions. The aim of the present study was to examine the protective effect of RG on cyclosporine A (CsA)-induced rat renal impairment and to evaluate the antioxidant mechanisms by which RG exerts its protective actions. Materials and Methods: Fifty male Sprague-Dawley rats weighing 250–300 g were randomly divided into five groups: administrations of olive oil (control, PO), RG (0.4 mg/kg, PO), CsA (30 mg/kg in olive oil, SC), RG (0.2 or 0.4 mg/kg, PO) plus CsA (30 mg/kg in olive oil SC) every day for 15 days. Results: SC administration of CsA (30 mg/kg) to rats produced marked elevations in the levels of renal impairment parameters such as urinary protein, N-acetyl-beta-D-glucosaminidase (NAG), serum creatinine (SCr), and blood urea nitrogen (BUN). It also caused histologic injury to the kidneys. Oral administration of RG (0.2 and 0.4 mg/kg) markedly decreased all the aforementioned changes. In addition, CsA caused increases in the levels of malondialdehyde (MDA) and decreases in superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GSR), glutathione-S-transferase (GST), and glutathione in kidney homogenate, which were reversed significantly by both doses of RG. Conclusion: The findings of our study indicate that RG may play an important role in protecting the kidney from oxidative insult. PMID:27635199

  17. Polar release of pathogenic Old World hantaviruses from renal tubular epithelial cells

    PubMed Central

    2012-01-01

    Background Epithelio- and endotheliotropic viruses often exert polarized entry and release that may be responsible for viral spread and dissemination. Hantaviruses, mostly rodent-borne members of the Bunyaviridae family infect epithelial and endothelial cells of different organs leading to organ dysfunction or even failure. Endothelial and renal epithelial cells belong to the target cells of Old World hantavirus. Therefore, we examined the release of hantaviruses in several renal epithelial cell culture models. We used Vero cells that are commonly used in hantavirus studies and primary human renal epithelial cells (HREpC). In addition, we analyzed MDCKII cells, an epithelial cell line of a dog kidney, which represents a widely accepted in vitro model of polarized monolayers for their permissiveness for hantavirus infection. Results Vero C1008 and primary HREpCs were grown on porous-support filter inserts for polarization. Monolayers were infected with hantavirus Hantaan (HTNV) and Puumala (PUUV) virus. Supernatants from the apical and basolateral chamber of infected cells were analyzed for the presence of infectious particles by re-infection of Vero cells. Viral antigen and infectious particles of HTNV and PUUV were exclusively detected in supernatants collected from the apical chamber of infected Vero C1008 cells and HREpCs. MDCKII cells were permissive for hantavirus infection and polarized MDCKII cells released infectious hantaviral particles from the apical surface corresponding to the results of Vero and primary human epithelial cells. Conclusions Pathogenic Old World hantaviruses are released from the apical surface of different polarized renal epithelial cells. We characterized MDCKII cells as a suitable polarized cell culture model for hantavirus infection studies. PMID:23194647

  18. Polar release of pathogenic Old World hantaviruses from renal tubular epithelial cells.

    PubMed

    Krautkrämer, Ellen; Lehmann, Maik J; Bollinger, Vanessa; Zeier, Martin

    2012-11-30

    Epithelio- and endotheliotropic viruses often exert polarized entry and release that may be responsible for viral spread and dissemination. Hantaviruses, mostly rodent-borne members of the Bunyaviridae family infect epithelial and endothelial cells of different organs leading to organ dysfunction or even failure. Endothelial and renal epithelial cells belong to the target cells of Old World hantavirus. Therefore, we examined the release of hantaviruses in several renal epithelial cell culture models. We used Vero cells that are commonly used in hantavirus studies and primary human renal epithelial cells (HREpC). In addition, we analyzed MDCKII cells, an epithelial cell line of a dog kidney, which represents a widely accepted in vitro model of polarized monolayers for their permissiveness for hantavirus infection. Vero C1008 and primary HREpCs were grown on porous-support filter inserts for polarization. Monolayers were infected with hantavirus Hantaan (HTNV) and Puumala (PUUV) virus. Supernatants from the apical and basolateral chamber of infected cells were analyzed for the presence of infectious particles by re-infection of Vero cells. Viral antigen and infectious particles of HTNV and PUUV were exclusively detected in supernatants collected from the apical chamber of infected Vero C1008 cells and HREpCs. MDCKII cells were permissive for hantavirus infection and polarized MDCKII cells released infectious hantaviral particles from the apical surface corresponding to the results of Vero and primary human epithelial cells. Pathogenic Old World hantaviruses are released from the apical surface of different polarized renal epithelial cells. We characterized MDCKII cells as a suitable polarized cell culture model for hantavirus infection studies.

  19. G418-mediated ribosomal read-through of a nonsense mutation causing autosomal recessive proximal renal tubular acidosis

    PubMed Central

    Azimov, Rustam; Abuladze, Natalia; Sassani, Pakan; Newman, Debra; Kao, Liyo; Liu, Weixin; Orozco, Nicholas; Ruchala, Piotr; Pushkin, Alexander; Kurtz, Ira

    2008-01-01

    Autosomal recessive proximal renal tubular acidosis is caused by mutations in the SLC4A4 gene encoding the electrogenic sodium bicarbonate cotransporter NBCe1-A. The mutations that have been characterized thus far result in premature truncation, mistargeting, or decreased function of the cotransporter. Despite bicarbonate treatment to correct the metabolic acidosis, extrarenal manifestations persist, including glaucoma, cataracts, corneal opacification, and mental retardation. Currently, there are no known therapeutic approaches that can specifically target mutant NBCe1-A proteins. In the present study, we tested the hypothesis that the NBCe1-A-Q29X mutation can be rescued in vitro by treatment with aminoglycoside antibiotics, which are known for their ability to suppress premature stop codons. As a model system, we cloned the NBCe1-A-Q29X mutant into a vector lacking an aminoglycoside resistance gene and transfected the mutant cotransporter in HEK293-H cells. Cells transfected with the NBCe1-A-Q29X mutant failed to express the cotransporter because of the premature stop codon. Treatment of the cells with G418 significantly increased the expression of the full-length cotransporter, as assessed by immunoblot analysis. Furthermore, immunocytochemical studies demonstrated that G418 treatment induced cotransporter expression on the plasma membrane whereas in the absence of G418, NBCe1-A-Q29X was not expressed. In HEK293-H cells transfected with the NBCe1-A-Q29X mutant not treated with G418, NBCe1-A-mediated flux was not detectable. In contrast, in cells transfected with the NBCe1-A-Q29X mutant, G418 treatment induced Na+- and HCO3−-dependent transport that did not differ from wild-type NBCe1-A function. G418 treatment in mock-transfected cells was without effect. In conclusion, G418 induces ribosomal read-through of the NBCe1-A-Q29X mutation in HEK293-H cells. These findings represent the first evidence that in the presence of the NBCe1-A-Q29X mutation that causes

  20. G418-mediated ribosomal read-through of a nonsense mutation causing autosomal recessive proximal renal tubular acidosis.

    PubMed

    Azimov, Rustam; Abuladze, Natalia; Sassani, Pakan; Newman, Debra; Kao, Liyo; Liu, Weixin; Orozco, Nicholas; Ruchala, Piotr; Pushkin, Alexander; Kurtz, Ira

    2008-09-01

    Autosomal recessive proximal renal tubular acidosis is caused by mutations in the SLC4A4 gene encoding the electrogenic sodium bicarbonate cotransporter NBCe1-A. The mutations that have been characterized thus far result in premature truncation, mistargeting, or decreased function of the cotransporter. Despite bicarbonate treatment to correct the metabolic acidosis, extrarenal manifestations persist, including glaucoma, cataracts, corneal opacification, and mental retardation. Currently, there are no known therapeutic approaches that can specifically target mutant NBCe1-A proteins. In the present study, we tested the hypothesis that the NBCe1-A-Q29X mutation can be rescued in vitro by treatment with aminoglycoside antibiotics, which are known for their ability to suppress premature stop codons. As a model system, we cloned the NBCe1-A-Q29X mutant into a vector lacking an aminoglycoside resistance gene and transfected the mutant cotransporter in HEK293-H cells. Cells transfected with the NBCe1-A-Q29X mutant failed to express the cotransporter because of the premature stop codon. Treatment of the cells with G418 significantly increased the expression of the full-length cotransporter, as assessed by immunoblot analysis. Furthermore, immunocytochemical studies demonstrated that G418 treatment induced cotransporter expression on the plasma membrane whereas in the absence of G418, NBCe1-A-Q29X was not expressed. In HEK293-H cells transfected with the NBCe1-A-Q29X mutant not treated with G418, NBCe1-A-mediated flux was not detectable. In contrast, in cells transfected with the NBCe1-A-Q29X mutant, G418 treatment induced Na(+)- and HCO(3)(-)-dependent transport that did not differ from wild-type NBCe1-A function. G418 treatment in mock-transfected cells was without effect. In conclusion, G418 induces ribosomal read-through of the NBCe1-A-Q29X mutation in HEK293-H cells. These findings represent the first evidence that in the presence of the NBCe1-A-Q29X mutation that

  1. Renal Integrin-Linked Kinase Depletion Induces Kidney cGMP-Axis Upregulation: Consequences on Basal and Acutely Damaged Renal Function

    PubMed Central

    Cano-Peñalver, José Luis; Griera, Mercedes; García-Jerez, Andrea; Hatem-Vaquero, Marco; Ruiz-Torres, María Piedad; Rodríguez-Puyol, Diego; de Frutos, Sergio; Rodríguez-Puyol, Manuel

    2015-01-01

    Soluble guanylyl cyclase (sGC) is activated by nitric oxide (NO) and produces cGMP, which activates cGMP-dependent protein kinases (PKG) and is hydrolyzed by specific phosphodiesterases (PDE). The vasodilatory and cytoprotective capacity of cGMP-axis activation results in a therapeutic strategy for several pathologies. Integrin-linked kinase (ILK), a major scaffold protein between the extracellular matrix and intracellular signaling pathways, may modulate the expression and functionality of the cGMP-axis–related proteins. We introduce ILK as a novel modulator in renal homeostasis as well as a potential target for cisplatin (CIS)-induced acute kidney injury (AKI) improvement. We used an adult mice model of depletion of ILK (cKD-ILK), which showed basal increase of sGC and PKG expressions and activities in renal cortex when compared with wildtype (WT) littermates. Twenty-four h activation of sGC activation with NO enhanced the filtration rate in cKD-ILK. During AKI, cKD-ILK maintained the cGMP-axis upregulation with consequent filtration rates enhancement and ameliorated CIS-dependent tubular epithelial-to-mesenchymal transition and inflammation and markers. To emphasize the role of cGMP-axis upregulation due to ILK depletion, we modulated the cGMP axis under AKI in vivo and in renal cultured cells. A suboptimal dose of the PDE inhibitor ZAP enhanced the beneficial effects of the ILK depletion in AKI mice. On the other hand, CIS increased contractility-related events in cultured glomerular mesangial cells and necrosis rates in cultured tubular cells; ILK depletion protected the cells while sGC blockade with ODQ fully recovered the damage. PMID:26562149

  2. Renal tubular handling of /sup 203/Hg/sup 2 +/ in the dog: a microinjection study

    SciTech Connect

    Cikrt, M.; Heller, J.

    1980-04-01

    /sup 203/HgCl/sub 2/ in trace amounts was injected together with (methoxy-/sup 3/H)inulin into the proximal convoluted tubules of the dog kidney superficial nephrons. Of the injected inulin, 97.3 +- 5.7% was recovered in the urine from the injected kidney. From the injected /sup 203/Hg only 8.2 +- 1.0% was recovered in the urine from the injected kidney and 0.4 +- 0.7% from the contralateral kidney. These results were not significantly influenced by intrarterial infusion of KCN, ouabain, or 2,4-dinitrophenol, indicating that there occurred no active tubular reabsorption of mercury. Of the injected /sup 203/Hg, 88.2 to 93.5% was recovered in the kidney whose tubules were punctured. When /sup 203/Hg was injected into peritubular capillary, only 1.2 +- 0.7% was recovered in the urine from the injected and 0.91 +- 0.2% from the contralateral kidney, this difference being not significant. Results are interpreted as lacking evidence for active transport mechanism of Hg/sup 2 +/ in the dog kidney under conditions of microinjection experiment.

  3. Facilitation by serum albumin of renal tubular secretion of organic anions.

    PubMed

    Besseghir, K; Mosig, D; Roch-Ramel, F

    1989-03-01

    The role of albumin in tubular secretion of the organic anions p-aminohippurate (PAH, 21% albumin-bound at 1 microM) and methotrexate (MTX, 55% bound at 1 microM), and of the organic cation N1-methylnicotinamide (NMN, not bound), was investigated in isolated rabbit S2 proximal tubules. PAH or MTX secretory rates were low in the absence of colloids or in the presence of 1 g/dl dextran 40, and were reversibly two- to sevenfold stimulated by either 1 g/dl bovine (BSA, either regular, defatted, and/or dialyzed) or rabbit serum albumin, or by dialyzed native rabbit plasma. NMN secretion was not stimulated by either dextran or albumin. Luminal BSA had no effect, but stimulation of PAH secretion was observed when albumin was present in both lumen and bath. This secretion was BSA concentration-dependent up to a 1 g/dl BSA. Saturation experiments suggested that 1 g/dl BSA may increase PAH apparent affinity for secretion, with no change in its maximum velocity. Albumin appears therefore to facilitate organic anion proximal secretion by an effect unrelated to oncotic pressure or to the extent of organic anion binding.

  4. Hypokalemia-Induced Rhabdomyolysis as a result of Distal Renal Tubular Acidosis in a Pregnant Woman: A Case Report and Literature Review.

    PubMed

    Srisuttayasathien, Manasawee

    2015-01-01

    Rhabdomyolysis in pregnancy is a rare occurrence. The manifestation of distal renal tubular acidosis (RTA) for the first time during adulthood is uncommon. According to a review of the literature, pregnancy may predispose individuals to rhabdomyolysis due to hypokalemia. A reduction in interstitial potassium ions could decrease muscular blood flow and lead to muscle injury. This report describes the case of a pregnant woman with rhabdomyolysis induced by hypokalemia resulting from distal RTA. The patient subsequently delivered a healthy newborn.

  5. Hypokalemia-Induced Rhabdomyolysis as a result of Distal Renal Tubular Acidosis in a Pregnant Woman: A Case Report and Literature Review

    PubMed Central

    Srisuttayasathien, Manasawee

    2015-01-01

    Rhabdomyolysis in pregnancy is a rare occurrence. The manifestation of distal renal tubular acidosis (RTA) for the first time during adulthood is uncommon. According to a review of the literature, pregnancy may predispose individuals to rhabdomyolysis due to hypokalemia. A reduction in interstitial potassium ions could decrease muscular blood flow and lead to muscle injury. This report describes the case of a pregnant woman with rhabdomyolysis induced by hypokalemia resulting from distal RTA. The patient subsequently delivered a healthy newborn. PMID:26788388

  6. Curcumin Suppresses Epithelial-Mesenchymal Transition of Renal Tubular Epithelial Cells through the Inhibition of Akt/mTOR Pathway.

    PubMed

    Zhu, Fang-Qiang; Chen, Min-Jia; Zhu, Ming; Zhao, Rong-Seng; Qiu, Wei; Xu, Xiang; Liu, Hong; Zhao, Hong-Wen; Yu, Rong-Jie; Wu, Xiong-Fei; Zhang, Keqin; Huang, Hong

    2017-01-01

    Curcumin has exhibited a protective effect against development of renal fibrosis in animal models, however, its underlying molecular mechanisms are largely unclear. Therefore, we investigated the anti-fibrosis effects of curcumin in transforming growth factor-β1 (TGF-β1)-induced epithelial-to-mesenchymal transition (EMT), and the mechanism by which it mediates the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Human kidney tubular epithelial cells (HKCs) were treated with TGF-β1 or curcumin alone, or TGF-β1 in combination with curcumin. The effect of curcumin on cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression of E-cadherin, cytokeratin, vimentin, alpha smooth muscle actin (α-SMA), fibroblast-specific protein 1 (FSP1) and key proteins of Akt/mammalian target of rapamycin (mTOR) pathway were analyzed by immunocytochemistry, real-time PCR and Western blot. Low dose curcumin (3.125 and 25 µmol/L) effectively promoted HKC proliferation. When HKCs were co-incubated with TGF-β1 and curcumin for 72 h, curcumin maintained the epithelial morphology in a dose-dependent manner, decreased expression of vimentin, α-SMA and FSP1 normally induced by TGF-β1, and increased expression of E-cadherin, cytokeratin. Importantly, we found that curcumin reduced Akt, mTOR and P70S6K phosphorylation, effectively suppressing the activity of the Akt/mTOR pathway in HKCs. Curcumin also promoted HKC proliferation, and antagonized TGF-β1-driven EMT through the inhibition of Akt/mTOR pathway activity, which may suggest an alternative therapy for renal fibrosis.

  7. Topological location and structural importance of the NBCe1-A residues mutated in proximal renal tubular acidosis.

    PubMed

    Zhu, Quansheng; Kao, Liyo; Azimov, Rustam; Newman, Debra; Liu, Weixin; Pushkin, Alexander; Abuladze, Natalia; Kurtz, Ira

    2010-04-30

    NBCe1-A electrogenically cotransports Na(+) and HCO(3)(-) across the basolateral membrane of renal proximal tubule cells. Eight missense mutations and 3 nonsense mutations in NBCe1-A cause severe proximal renal tubular acidosis (pRTA). In this study, the topologic properties and structural importance of the 8 endogenous residues mutated in pRTA and the in situ topology of NBCe1-A were examined by the substituted cysteine accessibility method. Of the 55 analyzed individually introduced cysteines, 8 were labeled with both membrane permeant (biotin maleimide (BM)) and impermeant (2-((5(6)-tetramethylrhodamine)carboxylamino)ethyl methanethiosulfonate (MTS-TAMRA)) sulfhydryl reagents, 4 with only BM, and 3 with only MTS-TAMRA. The location of the labeled and unlabeled introduced cysteines clearly indicates that the transmembrane region of NBCe1-A contains 14 transmembrane segments (TMs). In this in situ based NBCe1-A topology, residues mutated in pRTA (pRTA residues) are assigned as: Ser(427), TM1; Thr(485) and Gly(486), TM3; Arg(510) and Leu(522), TM4; Ala(799), TM10; and Arg(881), TM12. Substitution of pRTA residues with cysteines impaired the membrane trafficking of R510C and R881C, the remaining membrane-processed constructs had various impaired transport function. Surprisingly, none of the membrane-processed constructs was accessible to labeling with BM and MTS-TAMRA, nor were they functionally sensitive to the inhibition by (2-aminoethyl)methanethiosulfonate. Functional analysis of Thr(485) with different amino acid substitutions indicated it resides in a unique region important for NBCe1-A function. Our findings demonstrate that the pRTA residues in NBCe1-A are buried in the protein complex/lipid bilayer where they perform important structural roles.

  8. Topological Location and Structural Importance of the NBCe1-A Residues Mutated in Proximal Renal Tubular Acidosis*

    PubMed Central

    Zhu, Quansheng; Kao, Liyo; Azimov, Rustam; Newman, Debra; Liu, Weixin; Pushkin, Alexander; Abuladze, Natalia; Kurtz, Ira

    2010-01-01

    NBCe1-A electrogenically cotransports Na+ and HCO3− across the basolateral membrane of renal proximal tubule cells. Eight missense mutations and 3 nonsense mutations in NBCe1-A cause severe proximal renal tubular acidosis (pRTA). In this study, the topologic properties and structural importance of the 8 endogenous residues mutated in pRTA and the in situ topology of NBCe1-A were examined by the substituted cysteine accessibility method. Of the 55 analyzed individually introduced cysteines, 8 were labeled with both membrane permeant (biotin maleimide (BM)) and impermeant (2-((5(6)-tetramethylrhodamine)carboxylamino)ethyl methanethiosulfonate (MTS-TAMRA)) sulfhydryl reagents, 4 with only BM, and 3 with only MTS-TAMRA. The location of the labeled and unlabeled introduced cysteines clearly indicates that the transmembrane region of NBCe1-A contains 14 transmembrane segments (TMs). In this in situ based NBCe1-A topology, residues mutated in pRTA (pRTA residues) are assigned as: Ser427, TM1; Thr485 and Gly486, TM3; Arg510 and Leu522, TM4; Ala799, TM10; and Arg881, TM12. Substitution of pRTA residues with cysteines impaired the membrane trafficking of R510C and R881C, the remaining membrane-processed constructs had various impaired transport function. Surprisingly, none of the membrane-processed constructs was accessible to labeling with BM and MTS-TAMRA, nor were they functionally sensitive to the inhibition by (2-aminoethyl)methanethiosulfonate. Functional analysis of Thr485 with different amino acid substitutions indicated it resides in a unique region important for NBCe1-A function. Our findings demonstrate that the pRTA residues in NBCe1-A are buried in the protein complex/lipid bilayer where they perform important structural roles. PMID:20197274

  9. Differential activation of signaling pathways by low-osmolar and iso-osmolar radiocontrast agents in human renal tubular cells.

    PubMed

    Andreucci, Michele; Faga, Teresa; Russo, Domenico; Bertucci, Bernardo; Tamburrini, Oscar; Pisani, Antonio; Sabbatini, Massimo; Fuiano, Giorgio; Michael, Ashour

    2014-02-01

    Radiocontrast media (RCM)-induced nephrotoxicity (CIN) is a major clinical problem accounting for 12% of all hospital-acquired cases of acute kidney injury (AKI). The pathophysiology of AKI due to RCM is not well understood, but direct toxic effects on renal cells have been postulated as contributing to CIN. It is believed that iso-osmolar RCM (IOCM) are less nephrotoxic than low-osmolar RCM (LOCM) but clinical data have been controversial. We have investigated the intracellular signaling pathways that may be affected by the LOCM iomeprol (IOM) and the IOCM iodixanol (IOD). Both IOM and IOD caused a dramatic decrease in phosphorylation of the kinase Akt at Ser473 and Thr308 in human renal tubular (HK-2) cells, with IOM having a greater effect; IOM also caused a greater decrease in cell viability. IOM also had a greater effect on phosphorylation of p38 MAP kinases, JNKs, and NF-kB (Ser276), and caused a marked decrease in the phosphorylation of forkhead box O3a (FOXO3a) and signal transducer and activator of transcription 3 (STAT3). However, IOD caused a greater decrease in the phosphorylation of mTOR (Ser2448) and phospho-ERK 1/2 while both RCM caused a similar decrease in the phosphorylation of phospho-p70S6 kinase (Ser371). In vivo studies showed that both IOM and IOD caused a significant decrease in both pAkt (Ser473) and pERK 1/2 in rat kidneys. Our study gives an insight into the possible mechanism of toxicity of RCM via their action on intracellular signaling pathways and may help in developing pharmacological interventions for their side-effects. © 2013 Wiley Periodicals, Inc.

  10. HIV-1 viral protein r induces ERK and caspase-8 dependent apoptosis in renal tubular epithelial cells

    PubMed Central

    Snyder, Alexandra; Alsauskas, Zygimantas C.; Leventhal, Jeremy S.; Rosenstiel, Paul E.; Gong, Pengfei; Chan, Justin JK; Barley, Kevin; He, John C.; Klotman, Mary E.; Ross, Michael J.; Klotman, Paul E.

    2010-01-01

    Objective HIV-associated nephropathy is the most common cause of end stage renal disease in persons with HIV/AIDS and is characterized by focal glomerulosclerosis and dysregulated renal tubular epithelial cell (RTEC) proliferation and apoptosis. HIV-1 viral protein r (Vpr) has been implicated in HIV-induced RTEC apoptosis but the mechanisms of Vpr-induced RTEC apoptosis are unknown. The aim of this study was therefore to determine the mechanisms of Vpr-induced apoptosis in RTEC. Methods Apoptosis and caspase activation were analyzed in human RTEC cells (HK2) after transduction with Vpr-expressing and control lentiviral vectors. Bax and BID were inhibited with lentiviral shRNA, and ERK activation was blocked with the MEK1,2 inhibitor, U0126. Results Vpr induced apoptosis as indicated by caspase 3/7 activation, PARP-1 cleavage and mitochondrial injury. Vpr activated both caspases-8 and 9. Inhibition of Bax reduced Vpr-induced apoptosis, as reported in other cell types. Additionally, Vpr induced cleavage of BID to tBID and suppression of BID expression prevented Vpr-induced apoptosis. Since sustained ERK activation can activate caspase-8 in some cell types, we studied the role of ERK in Vpr-induced caspase-8 activation. Vpr induced sustained ERK activation in HK2 cells and incubation with U0126 reduced Vpr-induced caspase-8 activation, BID cleavage and apoptosis. We detected phosphorylated ERK in RTEC in HIVAN biopsy specimens by immunohistochemistry. Conclusions These studies delineate a novel pathway of Vpr-induced apoptosis in RTEC, which is mediated by sustained ERK activation, resulting in caspase 8-mediated cleavage of BID to tBID, thereby facilitating Bax-mediated mitochondrial injury and apoptosis. PMID:20404718

  11. Freezing/Thawing without Cryoprotectant Damages Native but not Decellularized Porcine Renal Tissue.

    PubMed

    Poornejad, Nafiseh; Frost, Timothy S; Scott, Daniel R; Elton, Brinden B; Reynolds, Paul R; Roeder, Beverly L; Cook, Alonzo D

    2015-01-01

    Whole organ decellularization of porcine renal tissue and recellularization with a patient's own cells would potentially overcome immunorejection, which is one of the most significant problems with allogeneic kidney transplantation. However, there are obstacles to achieving this goal, including preservation of the decellularized extracellular matrix (ECM), identifying the proper cell types, and repopulating the ECM before transplantation. Freezing biological tissue is the best option to avoid spoilage; however, it may damage the structure of the tissue or disrupt cellular membranes through ice crystal formation. Cryoprotectants have been used to repress ice formation during freezing, although cell toxicity can still occur. The effect of freezing/thawing on native (n = 10) and decellularized (n = 10) whole porcine kidneys was studied without using cryoprotectants. Results showed that the elastic modulus of native kidneys was reduced by a factor of 22 (P < 0.0001) by freezing/thawing or decellularization, while the elastic modulus for decellularized ECM was essentially unchanged by the freezing/thawing process (p = 0.0636). Arterial pressure, representative of structural integrity, was also reduced by a factor of 52 (P < 0.0001) after freezing/thawing for native kidneys, compared to a factor of 43 (P < 0.0001) for decellularization and a factor of 4 (P < 0.0001) for freezing/thawing decellularized structures. Both freezing/thawing and decellularization reduced stiffness, but the reductions were not additive. Investigation of the microstructure of frozen/thawed native and decellularized renal tissues showed increased porosity due to cell removal and ice crystal formation. Orcein and Sirius staining showed partial damage to elastic and collagen fibers after freezing/thawing. It was concluded that cellular damage and removal was more responsible for reducing stiffness than fibril destruction. Cell viability and growth were demonstrated on decellularized frozen

  12. Freezing/Thawing without Cryoprotectant Damages Native but not Decellularized Porcine Renal Tissue

    PubMed Central

    Poornejad, Nafiseh; Frost, Timothy S; Scott, Daniel R; Elton, Brinden B; Reynolds, Paul R; Roeder, Beverly L; Cook, Alonzo D

    2015-01-01

    abstract Whole organ decellularization of porcine renal tissue and recellularization with a patient's own cells would potentially overcome immunorejection, which is one of the most significant problems with allogeneic kidney transplantation. However, there are obstacles to achieving this goal, including preservation of the decellularized extracellular matrix (ECM), identifying the proper cell types, and repopulating the ECM before transplantation. Freezing biological tissue is the best option to avoid spoilage; however, it may damage the structure of the tissue or disrupt cellular membranes through ice crystal formation. Cryoprotectants have been used to repress ice formation during freezing, although cell toxicity can still occur. The effect of freezing/thawing on native (n = 10) and decellularized (n = 10) whole porcine kidneys was studied without using cryoprotectants. Results showed that the elastic modulus of native kidneys was reduced by a factor of 22 (P < 0.0001) by freezing/thawing or decellularization, while the elastic modulus for decellularized ECM was essentially unchanged by the freezing/thawing process (p = 0.0636). Arterial pressure, representative of structural integrity, was also reduced by a factor of 52 (P < 0.0001) after freezing/thawing for native kidneys, compared to a factor of 43 (P < 0.0001) for decellularization and a factor of 4 (P < 0.0001) for freezing/thawing decellularized structures. Both freezing/thawing and decellularization reduced stiffness, but the reductions were not additive. Investigation of the microstructure of frozen/thawed native and decellularized renal tissues showed increased porosity due to cell removal and ice crystal formation. Orcein and Sirius staining showed partial damage to elastic and collagen fibers after freezing/thawing. It was concluded that cellular damage and removal was more responsible for reducing stiffness than fibril destruction. Cell viability and growth were demonstrated on decellularized frozen

  13. The use of fibrous, supramolecular membranes and human tubular cells for renal epithelial tissue engineering: towards a suitable membrane for a bioartificial kidney.

    PubMed

    Dankers, Patricia Y W; Boomker, Jasper M; Huizinga-van der Vlag, Ali; Smedts, Frank M M; Harmsen, Martin C; van Luyn, Marja J A

    2010-11-10

    A bioartificial kidney, which is composed of a membrane cartridge with renal epithelial cells, can substitute important kidney functions in patients with renal failure. A particular challenge is the maintenance of monolayer integrity and specialized renal epithelial cell functions ex vivo. We hypothesized that this can be improved by electro-spun, supramolecular polymer membranes which show clear benefits in ease of processability. We found that after 7 d, in comparison to conventional microporous membranes, renal tubular cells cultured on top of our fibrous supramolecular membranes formed polarized monolayers, which is prerequisite for a well-functioning bioartificial kidney. In future, these supramolecular membranes allow for incorporation of peptides that may increase cell function even further.

  14. Characterisation of Damaged Tubular Composites by Acoustic Emission, Thermal Diffusivity Mapping and TSR-RGB Projection Technique

    NASA Astrophysics Data System (ADS)

    Chandarana, Neha; Lansiaux, Henri; Gresil, Matthieu

    2016-11-01

    An increase in the use of composite materials, owing to improved design and fabrication processes, has led to cost reductions in many industries. Resistance to corrosion, high specific strength, and stiffness are just a few of their many attractive properties. However, damage tolerance remains a major concern in the implementation of composites and uncertainty regarding component lifetimes can lead to over-design and under-use of such materials. A combination of non-destructive evaluation (NDE) and structural health monitoring (SHM) have shown promise in improving confidence by enabling data collection in-situ and in real time. In this work, infrared thermography (IRT) is employed for NDE of tubular composite specimens before and after impact. Four samples are impacted with energies of 5 J, 7.5 J, and 10 J by an un-instrumented falling weight set-up. Acoustic emissions (AE) are monitored using bonded piezoelectric sensors during one of the four impact tests. IRT data is used to generate diffusivity and thermal depth mappings of each sample using the thermographic signal reconstruction (TSR) red green blue (RGB) projection technique. Analysis of AE data alone for a 10 J impact suggest significant damage to the fibres and matrix; this is in good agreement with the generated thermal depth mappings for each sample, which indicate damage through multiple fibre layers. IRT and AE data are correlated and validated by optical micrographs taken along the cross section of damage.

  15. Characterisation of Damaged Tubular Composites by Acoustic Emission, Thermal Diffusivity Mapping and TSR-RGB Projection Technique

    NASA Astrophysics Data System (ADS)

    Chandarana, Neha; Lansiaux, Henri; Gresil, Matthieu

    2017-04-01

    An increase in the use of composite materials, owing to improved design and fabrication processes, has led to cost reductions in many industries. Resistance to corrosion, high specific strength, and stiffness are just a few of their many attractive properties. However, damage tolerance remains a major concern in the implementation of composites and uncertainty regarding component lifetimes can lead to over-design and under-use of such materials. A combination of non-destructive evaluation (NDE) and structural health monitoring (SHM) have shown promise in improving confidence by enabling data collection in-situ and in real time. In this work, infrared thermography (IRT) is employed for NDE of tubular composite specimens before and after impact. Four samples are impacted with energies of 5 J, 7.5 J, and 10 J by an un-instrumented falling weight set-up. Acoustic emissions (AE) are monitored using bonded piezoelectric sensors during one of the four impact tests. IRT data is used to generate diffusivity and thermal depth mappings of each sample using the thermographic signal reconstruction (TSR) red green blue (RGB) projection technique. Analysis of AE data alone for a 10 J impact suggest significant damage to the fibres and matrix; this is in good agreement with the generated thermal depth mappings for each sample, which indicate damage through multiple fibre layers. IRT and AE data are correlated and validated by optical micrographs taken along the cross section of damage.

  16. Influence of consumption of cadmium-polluted rice or Jinzu River water on occurrence of renal tubular dysfunction and/or Itai-itai disease.

    PubMed

    Kobayashi, Etsuko; Suwazono, Yasushi; Dochi, Mirei; Honda, Ryumon; Kido, Teruhiko

    2009-03-01

    The aim of this study was to clarify whether consumption of cadmium (Cd)-polluted rice or Jinzu River water exerted any influence on the occurrence of renal tubular dysfunction and/or Itai-itai disease. From the participants of health examinations conducted in 1967 and 1968, 3,078 subjects who had resided for >30 years in the present hamlet and were aged >50 years were selected as the target population and were divided according to their residence in 55 hamlets. In a multiple regression analysis, the regression coefficients between rice-Cd concentration and prevalence of abnormal urinary findings (proteinuria, glucosuria, or proteinuria with glucosuria) or patients with Itai-itai disease were statistically significant between both sexes. The correlation between the prevalence of users of Jinzu River water and the occurrence of glucosuria in men as well as abnormal urinary findings in women was not statistically significant. We surmise that eating Cd-polluted rice and drinking and/or cooking with Jinzu River water influenced the occurrence of Itai-itai disease. The occurrence of renal tubular dysfunction is likely to have also been influenced by both factors, with eating Cd-polluted rice having a greater impact on the occurrence of renal tubular dysfunction as compared to drinking and/or cooking with Jinzu River water.

  17. Cobalt Chloride Induces Expression and Function of Breast Cancer Resistance Protein (BCRP/ABCG2) in Human Renal Proximal Tubular Epithelial Cell Line HK-2.

    PubMed

    Nishihashi, Katsuki; Kawashima, Kei; Nomura, Takami; Urakami-Takebayashi, Yumiko; Miyazaki, Makoto; Takano, Mikihisa; Nagai, Junya

    2017-01-01

    The human breast cancer resistance protein (BCRP/ABCG2), a member of the ATP-binding cassette transporter family, is a drug transporter restricting absorption and enhancing excretion of many compounds including anticancer drugs. The cis-regulatory elements in the BCRP promoter include a hypoxia response element, i.e., the DNA binding site for hypoxia-inducible factor-1 (HIF-1). In this study, we investigated the effect of cobalt chloride, a chemical inducer of HIF-1α, on the expression and function of BCRP in human renal proximal tubular cell line HK-2. Cobalt chloride treatment significantly increased the mRNA expression of not only glucose transporter 1 (GLUT1), a typical HIF-1 target gene mRNA, but also ABCG2 mRNA in HK-2 cells. The BCRP inhibitor Ko143-sensitive accumulation of BCRP substrates such as Hoechst33342 and mitoxantrone was significantly enhanced by cobalt chloride treatment. In addition, treatment with cobalt chloride significantly increased the Ko143-sensitive accumulation of fluorescein isothiocyanate-labeled methotrexate in HK-2 cells. Furthermore, cobalt chloride treatment attenuated the cytotoxicity induced by mitoxantrone and methotrexate, which might be, at least in part, due to the increase in BCRP-mediated transport activity via HIF-1 activation. These findings indicate that HIF-1 activation protects renal proximal tubular cells against BCRP substrate-induced cytotoxicity by enhancing the expression and function of BCRP in renal proximal tubular cells.

  18. Congenital ureteropelvic junction obstruction: physiopathology, decoupling of tout court pelvic dilatation-obstruction semantic connection, biomarkers to predict renal damage evolution.

    PubMed

    Alberti, C

    2012-02-01

    The widespread use of fetal ultrasonography results in a frequent antenatally observation of hydronephrosis, ureteropelvic junction obstruction (UPJO) accounting for the greatest fraction of congenital obstructive nephropathy. UPJO may be considered, in most cases, as a functional obstructive condition, depending on defective fetal smooth muscle/nerve development at this level, with lack of peristaltic wave propagation--aperistaltic segment--and, therefore, poor urine ejection from the renal pelvis into the ureter. The UPJO-related physiopathologic events are, at first, the compliant dilatation of renal pelvis that, acting as hydraulic buffer, protects the renal parenchyma from the rising intrapelvic pressure-related potential damages, and, subsequently, beyond such phase of dynamic balance, the tubular cell stretch-stress induced by increased intratubular pressure and following parenchymal inflammatory lesions: inflammatory infiltrates, fibroblast proliferation, activation of myofibroblasts, tubulo-interstitial fibrosis. Reactive oxygen species (ROS), nitric oxide (NO), several chemo- and cytokines, growth factors, prostaglandins and eicosanoids, angiotensin-II are the main pathogenetic mediators of the obstructive nephropathy. Apoptosis of tubular cells is the major cause of the tubular atrophy, together with epithelial-mesenchymal transdifferentiation. Some criticisms on tout court semantic renal pelvis dilatation-obstruction connection have been raised considering that the renal pelvis expansion isn't, in any case, linked to an ostructive condition, as it may be verified by diuretic (furosemide) renogram together with scintiscan-based evaluation of differential renal function. In this regard, rather than repetitive invasive nuclear procedures that expose the children to ionizing radiations, an intriguing noninvasive strategy, based on the evaluation of urinary biomarkers and urinary proteome, can define the UPJO-related possible progress of parenchymal lesions

  19. Enhancing the Detection of Dysmorphic Red Blood Cells and Renal Tubular Epithelial Cells with a Modified Urinalysis Protocol

    PubMed Central

    Chu-Su, Yu; Shukuya, Kenichi; Yokoyama, Takashi; Lin, Wei-Chou; Chiang, Chih-Kang; Lin, Chii-Wann

    2017-01-01

    Urinary sediment is used to evaluate patients with possible urinary tract diseases. Currently, numerous protocols are applied to detect dysmorphic red blood cells (RBCs) and renal tubular epithelial cells (RTECs) in urinary sediment. However, distinct protocols are used by nephrologists and medical technologists for specimen concentration and observation, which leads to major discrepancies in the differential counts of formed elements such as dysmorphic RBCs and RTECs and might interfere with an accurate clinical diagnosis. To resolve these problems, we first tested a modified urinalysis protocol with an increased relative centrifuge force and concentration factor in 20 biopsy-confirmed glomerulonephritis patients with haematuria. We successfully improved the recovery ratio of dysmorphic RBCs in clinical specimens from 34.7% to 42.0% (P < 0.001). Furthermore, we confirmed the correlation between counts by the modified urinary protocol and Sysmex UF-1000i urinary flow cytometer (r ≥ 0.898, P < 0.001). A total of 28 types of isomorphic and dysmorphic RBCs were detected using a bright field microscope, with results comparable to those using a standard phase contrast microscope. Finally, we applied Sternheimer stain to enhance the contrast of RTECs in the urinary sediments. We concluded that this modified urinalysis protocol significantly enhanced the quality of urinalysis. PMID:28074941

  20. Hyperglycemia Does Not Affect Iron Mediated Toxicity of Cultured Endothelial and Renal Tubular Epithelial Cells: Influence of L-Carnosine.

    PubMed

    Zhang, Shiqi; Ntasis, Emmanouil; Kabtni, Sarah; van den Born, Jaap; Navis, Gerjan; Bakker, Stephan J L; Krämer, Bernhard K; Yard, Benito A; Hauske, Sibylle J

    2016-01-01

    Iron has been suggested to affect the clinical course of type 2 diabetes (T2DM) as accompanying increased intracellular iron accumulation may provide an alternative source for reactive oxygen species (ROS). Although carnosine has proven its therapeutic efficacy in rodent models of T2DM, little is known about its efficacy to protect cells from iron toxicity. We sought to assess if high glucose (HG) exposure makes cultured human umbilical vein endothelial cells (HUVECs) and renal proximal tubular epithelial cells (PTECs) more susceptible to metal induced toxicity and if this is ameliorated by L-carnosine. HUVECs and PTECs, cultured under normal glucose (5 mM, NG) or HG (30 mM), were challenged for 24 h with FeCl3. Cell viability was not impaired under HG conditions nor did HG increase susceptibility to FeCl3. HG did not change the expression of divalent metal transporter 1 (DMT1), ferroportin (IREG), and transferrin receptor protein 1 (TFRC). Irrespective of glucose concentrations L-carnosine prevented toxicity in a dose-dependent manner, only if it was present during the FeCl3 challenge. Hence our study indicates that iron induced cytotoxicity is not enhanced under HG conditions. L-Carnosine displayed a strong protective effect, most likely by chelation of iron mediated toxicity.

  1. Deafness and renal tubular acidosis in mice lacking the K-Cl co-transporter Kcc4.

    PubMed

    Boettger, Thomas; Hübner, Christian A; Maier, Hannes; Rust, Marco B; Beck, Franz X; Jentsch, Thomas J

    2002-04-25

    Hearing depends on a high K(+) concentration bathing the apical membranes of sensory hair cells. K(+) that has entered hair cells through apical mechanosensitive channels is transported to the stria vascularis for re-secretion into the scala media(). K(+) probably exits outer hair cells by KCNQ4 K(+) channels(), and is then transported by means of a gap junction system connecting supporting Deiters' cells and fibrocytes() back to the stria vascularis. We show here that mice lacking the K(+)/Cl(-) (K-Cl) co-transporter Kcc4 (coded for by Slc12a7) are deaf because their hair cells degenerate rapidly after the beginning of hearing. In the mature organ of Corti, Kcc4 is restricted to supporting cells of outer and inner hair cells. Our data suggest that Kcc4 is important for K(+) recycling() by siphoning K(+) ions after their exit from outer hair cells into supporting Deiters' cells, where K(+) enters the gap junction pathway. Similar to some human genetic syndromes(), deafness in Kcc4-deficient mice is associated with renal tubular acidosis. It probably results from an impairment of Cl(-) recycling across the basolateral membrane of acid-secreting alpha-intercalated cells of the distal nephron.

  2. A single nucleotide polymorphism in kidney anion exchanger 1 gene is associated with incomplete type 1 renal tubular acidosis

    PubMed Central

    Takeuchi, Takumi; Hattori-Kato, Mami; Okuno, Yumiko; Kanatani, Atsushi; Zaitsu, Masayoshi; Mikami, Koji

    2016-01-01

    Various conditions including distal renal tubular acidosis (dRTA) can induce stone formation in the kidney. dRTA is characterized by an impairment of urine acidification in the distal nephron. dRTA is caused by variations in genes functioning in intercalated cells including SLC4A1/AE1/Band3 transcribing two kinds of mRNAs encoding the Cl−/HCO3− exchanger in erythrocytes and that expressed in α-intercalated cells (kAE1). With the acid-loading test, 25% of urolithiasis patients were diagnosed with incomplete dRTA. In erythroid intron 3 containing the promoter region of kAE1, rs999716 SNP showed a significantly higher minor allele A frequency in incomplete dRTA compared with non-dRTA patients. The promoter regions of the kAE1 gene with the minor allele A at rs999716 downstream of the TATA box showed reduced promoter activities compared that with the major allele G. Patients with the A allele at rs999716 may express less kAE1 mRNA and protein in the intercalated cells, developing incomplete dRTA. PMID:27767102

  3. Familial distal renal tubular acidosis is associated with mutations in the red cell anion exchanger (Band 3, AE1) gene.

    PubMed Central

    Bruce, L J; Cope, D L; Jones, G K; Schofield, A E; Burley, M; Povey, S; Unwin, R J; Wrong, O; Tanner, M J

    1997-01-01

    All affected patients in four families with autosomal dominant familial renal tubular acidosis (dRTA) were heterozygous for mutations in their red cell HCO3-/Cl- exchanger, band 3 (AE1, SLC4A1) genes, and these mutations were not found in any of the nine normal family members studied. The mutation Arg589--> His was present in two families, while Arg589--> Cys and Ser613--> Phe changes were found in the other families. Linkage studies confirmed the co-segregation of the disease with a genetic marker close to AE1. The affected individuals with the Arg589 mutations had reduced red cell sulfate transport and altered glycosylation of the red cell band 3 N-glycan chain. The red cells of individuals with the Ser613--> Phe mutation had markedly increased red cell sulfate transport but almost normal red cell iodide transport. The erythroid and kidney isoforms of the mutant band 3 proteins were expressed in Xenopus oocytes and all showed significant chloride transport activity. We conclude that dominantly inherited dRTA is associated with mutations in band 3; but both the disease and its autosomal dominant inheritance are not related simply to the anion transport activity of the mutant proteins. PMID:9312167

  4. Novel AE1 mutations in recessive distal renal tubular acidosis. Loss-of-function is rescued by glycophorin A.

    PubMed

    Tanphaichitr, V S; Sumboonnanonda, A; Ideguchi, H; Shayakul, C; Brugnara, C; Takao, M; Veerakul, G; Alper, S L

    1998-12-15

    The AE1 gene encodes band 3 Cl-/HCO3- exchangers that are expressed both in the erythrocyte and in the acid-secreting, type A intercalated cells of the kidney. Kidney AE1 contributes to urinary acidification by providing the major exit route for HCO3- across the basolateral membrane. Several AE1 mutations cosegregate with dominantly transmitted nonsyndromic renal tubular acidosis (dRTA). However, the modest degree of in vitro hypofunction exhibited by these dRTA-associated mutations fails to explain the disease phenotype in light of the normal urinary acidification associated with the complete loss-of-function exhibited by AE1 mutations linked to dominant spherocytosis. We report here novel AE1 mutations linked to a recessive syndrome of dRTA and hemolytic anemia in which red cell anion transport is normal. Both affected individuals were triply homozygous for two benign mutations M31T and K56E and for the loss-of-function mutation, G701D. AE1 G701D loss-of-function was accompanied by impaired trafficking to the Xenopus oocyte surface. Coexpression with AE1 G701D of the erythroid AE1 chaperonin, glycophorin A, rescued both AE1-mediated Cl- transport and AE1 surface expression in oocytes. The genetic and functional data both suggest that the homozygous AE1 G701D mutation causes recessively transmitted dRTA in this kindred with apparently normal erythroid anion transport.

  5. Histopathological characterization of renal tubular and interstitial changes in 5/6 nephrectomized marmoset monkeys (Callithrix jacchus).

    PubMed

    Suzuki, Yui; Yamaguchi, Itaru; Myojo, Kensuke; Kimoto, Naoya; Imaizumi, Minami; Takada, Chie; Sanada, Hiroko; Takaba, Katsumi; Yamate, Jyoji

    2015-01-01

    Common marmosets (Callithrix jacchus) have become a useful animal model, particularly for development of biopharmaceuticals. While various renal failure models have been established in rodents, there is currently no acceptable model in marmosets. We analyzed the damaged renal tubules and tubulointerstitial changes (inflammation and fibrosis) of 5/6 nephrectomized (Nx) common marmosets by histopathological/immunohistochemical methods, and compared these findings to those in 5/6 Nx SD rats. In Nx marmosets and rats sacrificed at 5 and 13 weeks after Nx, variously dilated and atrophied renal tubules were seen in the cortex in common; however, the epithelial proliferating activity was much less in Nx marmosets. Furthermore, the degrees of inflammation and fibrosis seen in the affected cortex were more severe and massive in Nx marmosets with time-dependent increase. Interestingly, inflammation in Nx marmosets, of which degree was less in Nx rats, consisted of a large number of CD3-positive T cells and CD20-positive B cells (occasionally forming follicles), and a few CD68-positive macrophages. Based on these findings, lymphocytes might contribute to the progressive renal lesions in Nx marmosets. Fibrotic areas in Nx marmosets comprised myofibroblasts expressing vimentin and α-smooth muscle actin (α-SMA), whereas along with vimentin and α-SMA expressions, desmin was expressed in myofibroblasts in Nx rats. This study shows that there are some differences in renal lesions induced by Nx between marmosets and rats, which would provide useful, base-line information for pharmacology and toxicology studies using Nx marmosets.

  6. Brazilian Red Propolis Attenuates Hypertension and Renal Damage in 5/6 Renal Ablation Model

    PubMed Central

    Teles, Flávio; da Silva, Tarcilo Machado; da Cruz Júnior, Francisco Pessoa; Honorato, Vitor Hugo; de Oliveira Costa, Henrique; Barbosa, Ana Paula Fernandes; de Oliveira, Sabrina Gomes; Porfírio, Zenaldo; Libório, Alexandre Braga; Borges, Raquel Lerner; Fanelli, Camilla

    2015-01-01

    The pathogenic role of inflammation and oxidative stress in chronic kidney disease (CKD) is well known. Anti-inflammatories and antioxidant drugs has demonstrated significant renoprotection in experimental nephropathies. Moreover, the inclusion of natural antioxidants derived from food and herbal extracts (such as polyphenols, curcumin and lycopene) as an adjuvant therapy for slowing CKD progression has been largely tested. Brazilian propolis is a honeybee product, whose anti-inflammatory, antimicrobial and antioxidant effects have been widely shown in models of sepsis, cancer, skin irritation and liver fibrosis. Furthermore, previous studies demonstrated that this compound promotes vasodilation and reduces hypertension. However, potential renoprotective effects of propolis in CKD have never been investigated. The aim of this study was to evaluate the effects of a subtype of Brazilian propolis, the Red Propolis (RP), in the 5/6 renal ablation model (Nx). Adult male Wistar rats underwent Nx and were divided into untreated (Nx) and RP-treated (Nx+RP) groups, after 30 days of surgery; when rats already exhibited marked hypertension and proteinuria. Animals were observed for 90 days from the surgery day, when Nx+RP group showed significant reduction of hypertension, proteinuria, serum creatinine retention, glomerulosclerosis, renal macrophage infiltration and oxidative stress, compared to age-matched untreated Nx rats, which worsened progressively over time. In conclusion, RP treatment attenuated hypertension and structural renal damage in Nx model. Reduction of renal inflammation and oxidative stress could be a plausible mechanism to explain this renoprotection. PMID:25607548

  7. Brazilian red propolis attenuates hypertension and renal damage in 5/6 renal ablation model.

    PubMed

    Teles, Flávio; da Silva, Tarcilo Machado; da Cruz Júnior, Francisco Pessoa; Honorato, Vitor Hugo; de Oliveira Costa, Henrique; Barbosa, Ana Paula Fernandes; de Oliveira, Sabrina Gomes; Porfírio, Zenaldo; Libório, Alexandre Braga; Borges, Raquel Lerner; Fanelli, Camilla

    2015-01-01

    The pathogenic role of inflammation and oxidative stress in chronic kidney disease (CKD) is well known. Anti-inflammatories and antioxidant drugs has demonstrated significant renoprotection in experimental nephropathies. Moreover, the inclusion of natural antioxidants derived from food and herbal extracts (such as polyphenols, curcumin and lycopene) as an adjuvant therapy for slowing CKD progression has been largely tested. Brazilian propolis is a honeybee product, whose anti-inflammatory, antimicrobial and antioxidant effects have been widely shown in models of sepsis, cancer, skin irritation and liver fibrosis. Furthermore, previous studies demonstrated that this compound promotes vasodilation and reduces hypertension. However, potential renoprotective effects of propolis in CKD have never been investigated. The aim of this study was to evaluate the effects of a subtype of Brazilian propolis, the Red Propolis (RP), in the 5/6 renal ablation model (Nx). Adult male Wistar rats underwent Nx and were divided into untreated (Nx) and RP-treated (Nx+RP) groups, after 30 days of surgery; when rats already exhibited marked hypertension and proteinuria. Animals were observed for 90 days from the surgery day, when Nx+RP group showed significant reduction of hypertension, proteinuria, serum creatinine retention, glomerulosclerosis, renal macrophage infiltration and oxidative stress, compared to age-matched untreated Nx rats, which worsened progressively over time. In conclusion, RP treatment attenuated hypertension and structural renal damage in Nx model. Reduction of renal inflammation and oxidative stress could be a plausible mechanism to explain this renoprotection.

  8. Effect of eplerenone on hypertension-associated renal damage in rats: potential role of peroxisome proliferator activated