Homogentisate 1-2-Dioxygenase Downregulation in the Chronic Persistence of Pseudomonas aeruginosa Australian Epidemic Strain-1 in the CF Lung

PubMed Central

Harmer, Christopher J.; Wynn, Matthew; Pinto, Rachel; Cordwell, Stuart; Rose, Barbara R.; Harbour, Colin; Triccas, James A.; Manos, Jim

2015-01-01

Some Pseudomonas aeruginosa strains including Australian Epidemic Strain-1 (AES-1 or AUS-01) cause persistent chronic infection in cystic fibrosis (CF) patients, with greater morbidity and mortality. Factors conferring persistence are largely unknown. Previously we analysed the transcriptomes of AES-1 grown in Luria broth, nematode growth medium for Caenorhabditis elegans assay (both aerobic) and artificial sputum medium (mainly hypoxic). Transcriptional comparisons included chronic AES-1 strains against PAO1 and acute AES-1 (AES-1R) against its chronic isogen (AES-1M), isolated 10.5 years apart from a CF patient and not eradicated in the meantime. Prominent amongst genes downregulated in AES-1M in all comparisons was homogentisate-1-2-dioxygenase (hmgA); an oxygen-dependent gene known to be mutationally deactivated in many chronic infection strains of P. aeruginosa. To investigate if hmgA downregulation and deactivation gave similar virulence persistence profiles, a hmgA mutant made in UCBPP-PA14 utilising RedS-recombinase and AES-1M were assessed in the C. elegans virulence assay, and the C57BL/6 mouse for pulmonary colonisation and TNF-α response. In C. elegans, hmgA deactivation resulted in significantly increased PA14 virulence while hmgA downregulation reduced AES-1M virulence. AES-1M was significantly more persistent in mouse lung and showed a significant increase in TNF-α (p<0.0001), sustained even with no detectable bacteria. PA14ΔhmgA did not show increased TNF-α. This study suggests that hmgA may have a role in P. aeruginosa persistence in chronic infection and the results provide a starting point for clarifying the role of hmgA in chronic AES-1. PMID:26252386

Treatment of hypoxic-ischemic encephalopathy in mouse by transplantation of embryonic stem cell-derived cells.

PubMed

Ma, Jie; Wang, Yu; Yang, Jianhua; Yang, Min; Chang, Keun-A; Zhang, Linhua; Jiang, Feng; Li, Yi; Zhang, Zhonggong; Heo, Chaejeong; Suh, Yoo-Hun

2007-07-01

A 7-day-old hypoxic-ischemic encephalopathy (HIE) mouse model was used to study the effect of transplantation of embryonic stem (ES) cell-derived cells on the HIE. After the inducement in vitro, the ES cell-derived cells expressed Nestin and MAP-2, rather than GFAP mRNA. After transplantation, ES cell-derived cells can survive, migrate into the injury site, and specifically differentiate into neurons, showing improvement of the learning ability and memory of the HIE mouse at 8 months post-transplantation. The non-grafted HIE mouse brain showed typical pathological changes in the hippocampus and cerebral cortex, where the number of neurons was reduced, while in the cell graft group, number of the neurons increased in the same regions. Although further study is necessary to elucidate the precise mechanisms responsible for this functional recovery, we believe that ES cells have advantages for use as a donor source in HIE.

Accelerated acidosis in response to variable fetal heart rate decelerations in chronically hypoxic ovine fetuses.

PubMed

Amaya, Kevin E; Matushewski, Brad; Durosier, L Daniel; Frasch, Martin G; Richardson, Bryan S; Ross, Michael G

2016-02-01

Due to limitations of technology, clinicians are typically unable to determine if human fetuses are normoxic or moderately, chronically hypoxic. Risk factors for chronic hypoxia include fetal growth restriction, which is associated with an increased incidence of oligohydramnios and thus a risk for umbilical cord occlusion (UCO) and variable fetal heart rate (FHR) decelerations. At delivery, fetal growth restriction infants (<3rd percentile) have nearly twice the incidence of low Apgar scores and umbilical pH <7.0. Despite the risks of oligohydramnios and intermittent UCO, there is little understanding of the acid/base responses rates of chronically hypoxic fetuses to variable FHR decelerations as might occur during human labor. We sought to compare the increase in base deficit (BD) among chronically hypoxic as compared to normoxic ovine fetuses in response to simulated mild, moderate, and severe variable FHR decelerations. Near-term ovine fetuses were chronically prepared with brachial artery catheters and an inflatable umbilical cuff occluder. Following a recovery period, normoxic (n = 9) and spontaneously hypoxic (n = 5) fetuses were identified (arterial O2 saturation ≤55%). Both animal groups underwent graded, 1-minute occlusions every 2.5 minutes with 1 hour of mild (∼30 beats/min [bpm] decrease from baseline), 1 hour of moderate (∼60 bpm decrease from baseline), and up to 2 hours of severe (∼90 bpm decrease from baseline) variable FHR decelerations until fetal arterial pH reached 7.00, when occlusions were stopped. Repetitive UCO resulted in development of acidosis (pH <7.0) in both groups. Hypoxic and normoxic fetuses demonstrated similar BD increases in response to both mild (0.39, interquartile range [IQR] 0.28-0.45 vs 0.26, IQR 0.01-0.30 mEq/L/10 min, P = .25) and severe (1.97, IQR 1.50-2.43 vs 1.51, IQR 0.97-2.45 mEq/L/10 min, P = .63) variable decelerations. However, moderate variable decelerations increased BD in hypoxic fetuses at 2.5 times the rate of normoxic fetuses (0.97, IQR 0.52-1.72 vs 0.39, IQR 0.23-0.47 mEq/L/10 min, P = .03). During the recovery period, hypoxic fetuses cleared BD slower than normoxic fetuses (0.08 ± 0.02 vs 0.12 ± 0.03 mEq/L/min, P = .02). In comparison to normoxic fetuses, hypoxic fetuses can more rapidly progress to significant metabolic acidosis in response to moderate FHR variable decelerations, and more slowly recover with in utero resuscitation, likely a consequence of impaired placental function and fetal physiologic responses. Copyright © 2016 Elsevier Inc. All rights reserved.

Impact of the mitochondria-targeted antioxidant MitoQ on hypoxia-induced pulmonary hypertension.

PubMed

Pak, Oleg; Scheibe, Susan; Esfandiary, Azadeh; Gierhardt, Mareike; Sydykov, Akylbek; Logan, Angela; Fysikopoulos, Athanasios; Veit, Florian; Hecker, Matthias; Kroschel, Florian; Quanz, Karin; Erb, Alexandra; Schäfer, Katharina; Fassbinder, Mirja; Alebrahimdehkordi, Nasim; Ghofrani, Hossein A; Schermuly, Ralph T; Brandes, Ralf P; Seeger, Werner; Murphy, Michael P; Weissmann, Norbert; Sommer, Natascha

2018-02-01

Increased mitochondrial reactive oxygen species (ROS), particularly superoxide have been suggested to mediate hypoxic pulmonary vasoconstriction (HPV), chronic hypoxia-induced pulmonary hypertension (PH) and right ventricular (RV) remodelling.We determined ROS in acute, chronic hypoxia and investigated the effect of the mitochondria-targeted antioxidant MitoQ under these conditions.The effect of MitoQ or its inactive carrier substance, decyltriphenylphosphonium (TPP + ), on acute HPV (1% O 2 for 10 minutes) was investigated in isolated blood-free perfused mouse lungs. Mice exposed for 4 weeks to chronic hypoxia (10% O 2 ) or after banding of the main pulmonary artery (PAB) were treated with MitoQ or TPP + (50 mg/kg/day).Total cellular superoxide and mitochondrial ROS levels were increased in pulmonary artery smooth muscle cells (PASMC), but decreased in pulmonary fibroblasts in acute hypoxia. MitoQ significantly inhibited HPV and acute hypoxia-induced rise in superoxide concentration. ROS was decreased in PASMC, while it increased in the RV after chronic hypoxia. Correspondingly, MitoQ did not affect the development of chronic hypoxia-induced PH, but attenuated RV remodelling after chronic hypoxia as well as after PAB.Increased mitochondrial ROS of PASMC mediate acute HPV, but not chronic hypoxia-induced PH. MitoQ may be beneficial under conditions of exaggerated acute HPV. Copyright ©ERS 2018.

[The effect of 5-HD on expression of PKC-alpha in rats of chronic hypoxic pulmonary hypertension].

PubMed

Shu, Ying; Li, Qiu; Li, Yun-lei; Zhang, Li-ping; Chen, Cheng-shui

2011-08-01

To investigate the effect of mito chondrial K(ATP) channels (mitoK(ATP)) inhibitor 5-hydroxydecanoate(5-HD) on chronic hypoxic pulmonary artery hypertension (CHPAH) rats and its underlying mechanisms. Forty-eight male SD rats were equally divided into 4 groups randomly (n=12): normal group, hypoxia group, hypoxia + 5-HD group, hypoxia + Diazoxide group. Except the first group, the other three groups were put into hypoxic [O2 (10.0% +/- 0.3%] and nonrmobaric chamber for four weeks to establish chronic hypoxic model and received different interference. When the interference completed, right heart catheter was used to detect the mean pulmonary arterial pressure (mPAP) of each rat and PKC-alpha mRNA expression in pulmonary arteries was detected by reverse transcription-polymerase chain reaction (RT-PCR) and protein expression by Western blot. (mPAP was much higher in hypoxia group than that in normal group (P < 0.01) while in hypoxia + 5-HD group and hypoxia + diazoxide were decreased significantly compared to hypoxia group (P < 0.01). (2) The protein and mRNA levels of PKC-alpha in the hypoxic group were higher than those in normal group (P < 0.05). 5-HD plays a protective role on CHPAH. The mechanism of its effect may be attributed to inhibiting MitoK(ATP).

Permanently Hypoxic Cell Culture Yields Rat Bone Marrow Mesenchymal Cells with Higher Therapeutic Potential in the Treatment of Chronic Myocardial Infarction.

PubMed

Liu, Yihua; Yang, Xiaoxi; Maureira, Pablo; Falanga, Aude; Marie, Vanessa; Gauchotte, Guillaume; Poussier, Sylvain; Groubatch, Frederique; Marie, Pierre-Yves; Tran, Nguyen

2017-01-01

The mismatch between traditional in vitro cell culture conditions and targeted chronic hypoxic myocardial tissue could potentially hamper the therapeutic effects of implanted bone marrow mesenchymal stem cells (BMSCs). This study sought to address (i) the extent of change to BMSC biological characteristics in different in vitro culture conditions and (ii) the effectiveness of permanent hypoxic culture for cell therapy in treating chronic myocardial infarction (MI) in rats. rat BMSCs were harvested and cultured in normoxic (21% O2, n=27) or hypoxic conditions (5% O2, n=27) until Passage 4 (P4). Cell growth tests, flow cytometry, and Bio-Plex assays were conducted to explore variations in the cell proliferation, phenotype, and cytokine expression, respectively. In the in vivo set-up, P3-BMSCs cultured in normoxia (n=6) or hypoxia (n=6) were intramyocardially injected into rat hearts that had previously experienced 1-month-old MI. The impact of cell therapy on cardiac segmental viability and hemodynamic performance was assessed 1 month later by 2-Deoxy-2[18F]fluoro-D-glucose (18F-FDG) positron emission tomography (PET) imaging and pressure-volume catheter, respectively. Additional histomorphological examinations were conducted to evaluate inflammation, fibrosis, and neovascularization. Hypoxic preconditioning significantly enhanced rat BMSC clonogenic potential and proliferation without altering the multipotency. Different profiles of inflammatory, fibrotic, and angiogenic cytokine secretion were also documented, with a marked correlation observed between in vitro and in vivo proangiogenic cytokine expression and tissue neovessels. Hypoxic-preconditioned cells presented a beneficial effect on the myocardial viability of infarct segments and intrinsic contractility. Hypoxic-preconditioned BMSCs were able to benefit myocardial perfusion and contractility, probably by modulating the inflammation and promoting angiogenesis. © 2017 The Author(s). Published by S. Karger AG, Basel.

Adenovirus-mediated HIF-1α gene transfer promotes repair of mouse airway allograft microvasculature and attenuates chronic rejection

PubMed Central

Jiang, Xinguo; Khan, Mohammad A.; Tian, Wen; Beilke, Joshua; Natarajan, Ramesh; Kosek, Jon; Yoder, Mervin C.; Semenza, Gregg L.; Nicolls, Mark R.

2011-01-01

Chronic rejection, manifested as small airway fibrosis (obliterative bronchiolitis [OB]), is the main obstacle to long-term survival in lung transplantation. Recent studies demonstrate that the airways involved in a lung transplant are relatively hypoxic at baseline and that OB pathogenesis may be linked to ischemia induced by a transient loss of airway microvasculature. Here, we show that HIF-1α mediates airway microvascular repair in a model of orthotopic tracheal transplantation. Grafts with a conditional knockout of Hif1a demonstrated diminished recruitment of recipient-derived Tie2+ angiogenic cells to the allograft, impaired repair of damaged microvasculature, accelerated loss of microvascular perfusion, and hastened denudation of epithelial cells. In contrast, graft HIF-1α overexpression induced via an adenoviral vector prolonged airway microvascular perfusion, preserved epithelial integrity, extended the time window for the graft to be rescued from chronic rejection, and attenuated airway fibrotic remodeling. HIF-1α overexpression induced the expression of proangiogenic factors such as Sdf1, Plgf, and Vegf, and promoted the recruitment of vasoreparative Tie2+ cells. This study demonstrates that a therapy that enhances vascular integrity during acute rejection may promote graft health and prevent chronic rejection. PMID:21606594

Altered autonomic control of heart rate variability in the chronically hypoxic fetus.

PubMed

Shaw, C J; Allison, B J; Itani, N; Botting, K J; Niu, Y; Lees, C C; Giussani, D A

2018-03-31

Fetal heart rate variability (FHRV) has long been recognised as a powerful predictor of fetal wellbeing, and a decrease in FHRV is associated with fetal compromise. However, the mechanisms by which FHRV is reduced in the chronically hypoxic fetus have yet to be established. The sympathetic and parasympathetic influences on heart rate mature at different rates throughout fetal life, and can be assessed by time domain and power spectral analysis of FHRV. In this study of chronically instrumented fetal sheep in late gestation, we analysed FHRV daily over a 16 day period towards term, and compared changes between fetuses of control and chronically hypoxic pregnancy. We show that FHRV in sheep is reduced by chronic hypoxia, predominantly due to dysregulation of the sympathetic control of the fetal heart rate. This presents a potential mechanism by which a reduction in indices of FHRV predicts fetuses at increased risk of neonatal morbidity and mortality in humans. Reduction in overall FHRV may therefore provide a biomarker that autonomic dysregulation of fetal heart rate control has taken place in a fetus where uteroplacental dysfunction is suspected. Although fetal heart rate variability (FHRV) has long been recognised as a powerful predictor of fetal wellbeing, the mechanisms by which it is reduced in the chronically hypoxic fetus have yet to be established. In particular, the physiological mechanism underlying the reduction of short term variation (STV) in fetal compromise remains unclear. In this study, we present a longitudinal study of the development of autonomic control of FHRV, assessed by indirect indices, time domain and power spectral analysis, in normoxic and chronically hypoxic, chronically catheterised, singleton fetal sheep over the last third of gestation. We used isobaric chambers able to maintain pregnant sheep for prolonged periods in hypoxic conditions (stable fetal femoral arterial PO2 10-12 mmHg), and a customised wireless data acquisition system to record beat-to-beat variation in the fetal heart rate. We determined in vivo longitudinal changes in overall FHRV and the sympathetic and parasympathetic contribution to FHRV in hypoxic (n = 6) and normoxic (n = 6) ovine fetuses with advancing gestational age. Normoxic fetuses show gestational age-related increases in overall indices of FHRV, and in the sympathetic nervous system contribution to FHRV (P < 0.001). Conversely, gestational age-related increases in overall FHRV were impaired by exposure to chronic hypoxia, and there was evidence of suppression of the sympathetic nervous system control of FHRV after 72 h of exposure to hypoxia (P < 0.001). This demonstrates that exposure to late gestation isolated chronic fetal hypoxia has the potential to alter the development of the autonomic nervous system control of FHRV in sheep. This presents a potential mechanism by which a reduction in indices of FHRV in human fetuses affected by uteroplacental dysfunction can predict fetuses at increased risk. © 2018 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Mouse model of necrotic tuberculosis granulomas develops hypoxic lesions.

PubMed

Harper, Jamie; Skerry, Ciaran; Davis, Stephanie L; Tasneen, Rokeya; Weir, Mariah; Kramnik, Igor; Bishai, William R; Pomper, Martin G; Nuermberger, Eric L; Jain, Sanjay K

2012-02-15

Preclinical evaluation of tuberculosis drugs is generally limited to mice. However, necrosis and hypoxia, key features of human tuberculosis lesions, are lacking in conventional mouse strains. We used C3HeB/FeJ mice, which develop necrotic lesions in response to Mycobacterium tuberculosis infection. Positron emission tomography in live infected animals, postmortem pimonidazole immunohistochemistry, and bacterial gene expression analyses were used to assess whether tuberculosis lesions in C3HeB/FeJ are hypoxic. Efficacy of combination drug treatment, including PA-824, active against M. tuberculosis under hypoxic conditions, was also evaluated. Tuberculosis lesions in C3HeB/FeJ (but not BALB/c) were found to be hypoxic and associated with up-regulation of known hypoxia-associated bacterial genes (P < .001). Contrary to sustained activity reported elsewhere in BALB/c mice, moxifloxacin and pyrazinamide (MZ) combination was not bactericidal beyond 3 weeks in C3HeB/FeJ. Although PA-824 added significant activity, the novel combination of PA-824 and MZ was less effective than the standard first-line regimen in C3HeB/FeJ. We demonstrate that tuberculosis lesions in C3HeB/FeJ are hypoxic. Activities of some key tuberculosis drug regimens in development are represented differently in C3HeB/FeJ versus BALB/c mice. Because C3HeB/FeJ display key features of human tuberculosis, this strain warrants evaluation as a more pathologically relevant model for preclinical studies.

Beneficial and detrimental role of adenosine signaling in diseases and therapy

PubMed Central

Liu, Hong

2015-01-01

Adenosine is a major signaling nucleoside that orchestrates cellular and tissue adaptation under energy depletion and ischemic/hypoxic conditions by activation of four G protein-coupled receptors (GPCR). The regulation and generation of extracellular adenosine in response to stress are critical in tissue protection. Both mouse and human studies reported that extracellular adenosine signaling plays a beneficial role during acute states. However, prolonged excess extracellular adenosine is detrimental and contributes to the development and progression of various chronic diseases. In recent years, substantial progress has been made to understand the role of adenosine signaling in different conditions and to clarify its significance during the course of disease progression in various organs. These efforts have and will identify potential therapeutic possibilities for protection of tissue injury at acute stage by upregulation of adenosine signaling or attenuation of chronic disease progression by downregulation of adenosine signaling. This review is to summarize current progress and the importance of adenosine signaling in different disease stages and its potential therapeutic effects. PMID:26316513

Hypoxic Stress Forces Irreversible Differentiation of a Majority of Mouse Trophoblast Stem Cells Despite FGF4.

PubMed

Yang, Yu; Arenas-Hernandez, Marcia; Gomez-Lopez, Nardhy; Dai, Jing; Parker, Graham C; Puscheck, Elizabeth E; Rappolee, Daniel A

2016-11-01

Hypoxic, hyperosmotic, and genotoxic stress slow mouse trophoblast stem cell (mTSC) proliferation, decrease potency/stemness, and increase differentiation. Previous reports suggest a period of reversibility in stress-induced mTSC differentiation. Here we show that hypoxic stress at 0.5% O 2 decreased potency factor protein by ∼60%-90% and reduced growth to nil. Hypoxia caused a 35-fold increase in apoptosis at Day 3 and a 2-fold increase at Day 6 above baseline. The baseline apoptosis rate was only 0.3%. Total protein was never less than baseline during hypoxic treatment, suggesting 0.5% O 2 is a robust, nonmorbid stressor. Hypoxic stress induced ∼50% of trophoblast giant cell (TGC) differentiation with a simultaneous 5- to 6-fold increase in the TGC product antiluteolytic prolactin family 3, subfamily d, member 1 (PRL3D1), despite the presence of fibroblast growth factor 4 (FGF4). Hypoxia-induced TGC differentiation was also supported by potency and differentiation mRNA marker analysis. FGF4 removal at 20% O 2 committed cell fate towards irreversible differentiation at 2 days, with similar TGC percentages after an additional 3 days of culture under potency conditions when FGF4 was readded or under differentiation conditions without FGF4. However, hypoxic stress required 4 days to irreversibly differentiate cells. Runted stem cell growth, forced differentiation of fewer cells, and irreversible differentiation limit total available stem cell population. Were mTSCs to respond to stress in a similar mode in vivo, miscarriage might occur as a result, which should be tested in the future. © 2016 by the Society for the Study of Reproduction, Inc.

Hypoxia-driven mechanism of vemurafenib resistance in melanoma

PubMed Central

Qin, Yong; Roszik, Jason; Chattopadhyay, Chandrani; Hashimoto, Yuuri; Liu, Chengwen; Cooper, Zachary A.; Wargo, Jennifer A.; Hwu, Patrick; Ekmekcioglu, Suhendan; Grimm, Elizabeth A.

2016-01-01

Melanoma is molecularly and structurally heterogeneous, with some tumor cells existing under hypoxic conditions. Our cell growth assays showed that under controlled hypoxic conditions, BRAF(V600E) melanoma cells rapidly became resistant to vemurafenib. By employing both a three-dimensional (3D) spheroid model and a two-dimensional (2D) hypoxic culture system to model hypoxia in vivo, we identified upregulation of HGF/MET signaling as a major mechanism associated with vemurafenib resistance as compared to 2D standard tissue culture in ambient air. We further confirmed that the upregulation of HGF/MET signaling was evident in drug-resistant melanoma patient tissues and mouse xenografts. Pharmacologic inhibition of the c-Met/Akt pathway restored the sensitivity of melanoma spheroids or 2D hypoxic cultures to vemurafenib. PMID:27458138

Enhanced cell survival and paracrine effects of mesenchymal stem cells overexpressing hepatocyte growth factor promote cardioprotection in myocardial infarction

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

Zhao, Liyan; Liu, Xiaolin; Zhang, Yuelin

Poor cell survival post transplantation compromises the therapeutic benefits of mesenchymal stem cells (MSCs) in myocardial infarction (MI). Hepatocyte growth factor (HGF) is an important cytokine for angiogenesis, anti-inflammation and anti-apoptosis. This study aimed to evaluate the cardioprotective effects of MSCs overexpressing HGF in a mouse model of MI. The apoptosis of umbilical cord-derived MSCs (UC-MSCs) and HGF-UC-MSCs under normoxic and hypoxic conditions was detected. The conditioned medium (CdM) of UC-MSCs and HGF-UC-MSCs under a hypoxic condition was harvested and its protective effect on neonatal cardiomyocytes (NCMs) exposed to a hypoxic challenge was examined. UC-MSCs and HGF-UC-MSCs were transplanted intomore » the peri-infarct region in mice following MI and heart function assessed 4 weeks post transplantation. The apoptosis of HGF-UC-MSCs under hypoxic conditions was markedly decreased compared with that of UC-MSCs. NCMs treated with HGF-UC-MSC hypoxic CdM (HGF-UC-MSCs-hy-CdM) exhibited less cell apoptosis in response to hypoxic challenge than those treated with UC-MSC hypoxic CdM (UC-MSCs-hy-CdM). HGF-UC-MSCs-hy-CdM released the inhibited p-Akt and lowered the enhanced ratio of Bax/Bcl-2 induced by hypoxia in the NCMs. HGF-UC-MSCs-hy-CdM expressed higher levels of HGF, EGF, bFGF and VEGF than UC-MSCs-hy-CdM. Transplantation of HGF-UC-MSCs or UC-MSCs greatly improved heart function in the mouse model of MI. Compared with UC-MSCs, transplantation of HGF-UC-MSCs was associated with less cardiomyocyte apoptosis, enhanced angiogenesis and increased proliferation of cardiomyocytes. This study may provide a novel therapeutic strategy for MSC-based therapy in cardiovascular disease.« less

Metabolic Profiles in Ovine Carotid Arteries with Developmental Maturation and Long-Term Hypoxia

PubMed Central

Goyal, Ravi; Longo, Lawrence D.

2015-01-01

Background Long-term hypoxia (LTH) is an important stressor related to health and disease during development. At different time points from fetus to adult, we are exposed to hypoxic stress because of placental insufficiency, high-altitude residence, smoking, chronic anemia, pulmonary, and heart disorders, as well as cancers. Intrauterine hypoxia can lead to fetal growth restriction and long-term sequelae such as cognitive impairments, hypertension, cardiovascular disorders, diabetes, and schizophrenia. Similarly, prolonged hypoxic exposure during adult life can lead to acute mountain sickness, chronic fatigue, chronic headache, cognitive impairment, acute cerebral and/or pulmonary edema, and death. Aim LTH also can lead to alteration in metabolites such as fumarate, 2-oxoglutarate, malate, and lactate, which are linked to epigenetic regulation of gene expression. Importantly, during the intrauterine life, a fetus is under a relative hypoxic environment, as compared to newborn or adult. Thus, the changes in gene expression with development from fetus to newborn to adult may be as a consequence of underlying changes in the metabolic profile because of the hypoxic environment along with developmental maturation. To examine this possibility, we examined the metabolic profile in carotid arteries from near-term fetus, newborn, and adult sheep in both normoxic and long-term hypoxic acclimatized groups. Results Our results demonstrate that LTH differentially regulated glucose metabolism, mitochondrial metabolism, nicotinamide cofactor metabolism, oxidative stress and antioxidants, membrane lipid hydrolysis, and free fatty acid metabolism, each of which may play a role in genetic-epigenetic regulation. PMID:26110419

Spatial differences of cellular origins and in vivo hypoxia modify contractile properties of pulmonary artery smooth muscle cells: lessons for arterial tissue engineering.

PubMed

Hall, S M; Soueid, A; Smith, T; Brown, R A; Haworth, S G; Mudera, V

2007-01-01

Tissue engineering of functional arteries is challenging. Within the pulmonary artery wall, smooth muscle cells (PASMCs) have site-specific developmental and functional phenotypes, reflecting differing contractile roles. The force generated by PASMCs isolated from the inner 25% and outer 50% of the media of intrapulmonary elastic arteries from five normal and eight chronically hypoxic (hypertensive) 14 day-old piglets was quantified in a three-dimensional (3D) collagen construct, using a culture force monitor. Outer medial PASMCs from normal piglets exerted more force (528 +/- 50 dynes) than those of hypoxic piglets (177 +/- 42 dynes; p < 0.01). Force generation by inner medial PASMCs from normal and hypoxic piglets was similar (349 +/- 35 and 239 +/- 60 dynes). In response to agonist (thromboxane) stimulation, all PASMCs from normal and hypoxic piglets contracted, but the increase in force generated by outer and inner hypoxic PASMCs (ranges 13-72 and 14-56 dynes) was less than by normal PASMCs (ranges 27-154 and 34-159 dynes, respectively; p < 0.05 for both). All hypoxic PASMCs were unresponsive to antagonist (sodium nitroprusside) stimulation, all normal PASMCs relaxed (range - 87 to - 494 dynes). Myosin heavy chain expression by both hypoxic PASMC phenotypes was less than normal (p < 0.05 for both), as was the activity of focal adhesion kinase, regulating contraction, in hypoxic inner PASMCs (p < 0.01). Chronic hypoxia resulted in the development of abnormal PASMC phenotypes, which in collagen constructs exhibited a reduction in contractile force and reactivity to agonists. Characterization of the mechanical response of spatially distinct cells and modification of their behaviour by hypoxia is critical for successful tissue engineering of major blood vessels.

Accumulation of p62 in degenerated spinal cord under chronic mechanical compression

PubMed Central

Tanabe, Fumito; Yone, Kazunori; Kawabata, Naoya; Sakakima, Harutoshi; Matsuda, Fumiyo; Ishidou, Yasuhiro; Maeda, Shingo; Abematsu, Masahiko; Komiya, Setsuro

2011-01-01

Intracellular accumulation of altered proteins, including p62 and ubiquitinated proteins, is the basis of most neurodegenerative disorders. The relationship among the accumulation of altered proteins, autophagy, and spinal cord dysfunction by cervical spondylotic myelopathy has not been clarified. We examined the expression of p62 and autophagy markers in the chronically compressed spinal cord of tiptoe-walking Yoshimura mice. In addition, we examined the expression and roles of p62 and autophagy in hypoxic neuronal cells. Western blot analysis showed the accumulation of p62, ubiquitinated proteins, and microtubule-associated protein 1 light chain 3 (LC3), an autophagic marker, in the compressed spinal cord. Immunohistochemical examinations showed that p62 accumulated in neurons, axons, astrocytes, and oligodendrocytes. Electron microscopy showed the expression of autophagy markers, including autolysosomes and autophagic vesicles, in the compressed spinal cord. These findings suggest the presence of p62 and autophagy in the degenerated compressed spinal cord. Hypoxic stress increased the expression of p62, ubiquitinated proteins, and LC3-II in neuronal cells. In addition, LC3 turnover assay and GFP-LC3 cleavage assay showed that hypoxic stress increased autophagy flux in neuronal cells. These findings suggest that hypoxic stress induces accumulation of p62 and autophagy in neuronal cells. The forced expression of p62 decreased the number of neuronal cells under hypoxic stress. These findings suggest that p62 accumulation under hypoxic stress promotes neuronal cell death. Treatment with 3-methyladenine, an autophagy inhibitor decreased the number of neuronal cells, whereas lithium chloride, an autophagy inducer increased the number of cells under hypoxic stress. These findings suggest that autophagy promotes neuronal cell survival under hypoxic stress. Our findings suggest that pharmacological inducers of autophagy may be useful for treating cervical spondylotic myelopathy patients. PMID:22082874

Adjustments in cholinergic, adrenergic and purinergic control of cardiovascular function in snapping turtle embryos (Chelydra serpentina) incubated in chronic hypoxia.

PubMed

Eme, John; Rhen, Turk; Crossley, Dane A

2014-10-01

Adenosine is an endogenous nucleoside that acts via G-protein coupled receptors. In vertebrates, arterial or venous adenosine injection causes a rapid and large bradycardia through atrioventricular node block, a response mediated by adenosine receptors that inhibit adenylate cyclase and decrease cyclic AMP concentration. Chronic developmental hypoxia has been shown to alter cardioregulatory mechanisms in reptile embryos, but adenosine's role in mediating these responses is not known. We incubated snapping turtle embryos under chronic normoxic (N21; 21 % O2) or chronic hypoxic conditions (H10; 10 % O2) beginning at 20 % of embryonic incubation. H10 embryos at 90 % of incubation were hypotensive relative to N21 embryos in both normoxic and hypoxic conditions. Hypoxia caused a hypotensive bradycardia in both N21 and H10 embryos during the initial 30 min of exposure; however, f H and P m both trended towards increasing during the subsequent 30 min, and H10 embryos were tachycardic relative to N21 embryos in hypoxia. Following serial ≥1 h exposure to normoxic and hypoxic conditions, a single injection of adenosine (1 mg kg(-1)) was given. N21 and H10 embryos responded to adenosine injection with a rapid and large hypotensive bradycardia in both normoxia and hypoxia. Gene expression for adenosine receptors were quantified in cardiac tissue, and Adora1 mRNA was the predominant receptor subtype with transcript levels 30-82-fold higher than Adora2A or Adora2B. At 70 % of incubation, H10 embryos had lower Adora1 and Adora2B expression compared to N21 embryos. Expression of Adora1 and Adora2B decreased in N21 embryos during development and did not differ from H10 embryos at 90 % of incubation. Similar to previous results in normoxia, H10 embryos in hypoxia were chronically tachycardic compared to N21 embryos before and after complete cholinergic and adrenergic blockade. Chronic hypoxia altered the development of normal cholinergic and adrenergic tone, as well as adenosine receptor mRNA levels. This study demonstrates that adenosine may be a major regulator of heart rate in developing snapping turtle embryos, and that chronic hypoxic incubation alters the response to hypoxic exposure.

Accumulation of p62 in degenerated spinal cord under chronic mechanical compression: functional analysis of p62 and autophagy in hypoxic neuronal cells.

PubMed

Tanabe, Fumito; Yone, Kazunori; Kawabata, Naoya; Sakakima, Harutoshi; Matsuda, Fumiyo; Ishidou, Yasuhiro; Maeda, Shingo; Abematsu, Masahiko; Komiya, Setsuro; Setoguchi, Takao

2011-12-01

Intracellular accumulation of altered proteins, including p62 and ubiquitinated proteins, is the basis of most neurodegenerative disorders. The relationship among the accumulation of altered proteins, autophagy, and spinal cord dysfunction by cervical spondylotic myelopathy has not been clarified. We examined the expression of p62 and autophagy markers in the chronically compressed spinal cord of tiptoe-walking Yoshimura mice. In addition, we examined the expression and roles of p62 and autophagy in hypoxic neuronal cells. Western blot analysis showed the accumulation of p62, ubiquitinated proteins, and microtubule-associated protein 1 light chain 3 (LC3), an autophagic marker, in the compressed spinal cord. Immunohistochemical examinations showed that p62 accumulated in neurons, axons, astrocytes, and oligodendrocytes. Electron microscopy showed the expression of autophagy markers, including autolysosomes and autophagic vesicles, in the compressed spinal cord. These findings suggest the presence of p62 and autophagy in the degenerated compressed spinal cord. Hypoxic stress increased the expression of p62, ubiquitinated proteins, and LC3-II in neuronal cells. In addition, LC3 turnover assay and GFP-LC3 cleavage assay showed that hypoxic stress increased autophagy flux in neuronal cells. These findings suggest that hypoxic stress induces accumulation of p62 and autophagy in neuronal cells. The forced expression of p62 decreased the number of neuronal cells under hypoxic stress. These findings suggest that p62 accumulation under hypoxic stress promotes neuronal cell death. Treatment with 3-methyladenine, an autophagy inhibitor decreased the number of neuronal cells, whereas lithium chloride, an autophagy inducer increased the number of cells under hypoxic stress. These findings suggest that autophagy promotes neuronal cell survival under hypoxic stress. Our findings suggest that pharmacological inducers of autophagy may be useful for treating cervical spondylotic myelopathy patients.

Limited Activity of Clofazimine as a Single Drug in a Mouse Model of Tuberculosis Exhibiting Caseous Necrotic Granulomas

PubMed Central

Irwin, Scott M.; Gruppo, Veronica; Brooks, Elizabeth; Gilliland, Janet; Scherman, Michael; Reichlen, Matthew J.; Leistikow, Rachel; Kramnik, Igor; Nuermberger, Eric L.; Voskuil, Martin I.

2014-01-01

New drugs and drugs with a novel mechanism of action are desperately needed to shorten the duration of tuberculosis treatment, to prevent the emergence of drug resistance, and to treat multiple-drug-resistant strains of Mycobacterium tuberculosis. Recently, there has been renewed interest in clofazimine (CFZ). In this study, we utilized the C3HeB/FeJ mouse model, possessing highly organized, hypoxic pulmonary granulomas with caseous necrosis, to evaluate CFZ monotherapy in comparison to results with BALB/c mice, which form only multifocal, coalescing cellular aggregates devoid of caseous necrosis. While CFZ treatment was highly effective in BALB/c mice, its activity was attenuated in the lungs of C3HeB/FeJ mice. This lack of efficacy was directly related to the pathological progression of disease in these mice, since administration of CFZ prior to the formation of hypoxic, necrotic granulomas reconstituted bactericidal activity in this mouse strain. These results support the continued use of mouse models of tuberculosis infection which exhibit a granulomatous response in the lungs that more closely resembles the pathology found in human disease. PMID:24798275

CD44 Interacts with HIF-2α to Modulate the Hypoxic Phenotype of Perinecrotic and Perivascular Glioma Cells.

PubMed

Johansson, Elinn; Grassi, Elisa S; Pantazopoulou, Vasiliki; Tong, Bei; Lindgren, David; Berg, Tracy J; Pietras, Elin J; Axelson, Håkan; Pietras, Alexander

2017-08-15

Hypoxia-inducible factors enhance glioma stemness, and glioma stem cells have an amplified hypoxic response despite residing within a perivascular niche. Still, little is known about differential HIF regulation in stem versus bulk glioma cells. We show that the intracellular domain of stem cell marker CD44 (CD44ICD) is released at hypoxia, binds HIF-2α (but not HIF-1α), enhances HIF target gene activation, and is required for hypoxia-induced stemness in glioma. In a glioma mouse model, CD44 was restricted to hypoxic and perivascular tumor regions, and in human glioma, a hypoxia signature correlated with CD44. The CD44ICD was sufficient to induce hypoxic signaling at perivascular oxygen tensions, and blocking CD44 cleavage decreased HIF-2α stabilization in CD44-expressing cells. Our data indicate that the stem cell marker CD44 modulates the hypoxic response of glioma cells and that the pseudo-hypoxic phenotype of stem-like glioma cells is achieved by stabilization of HIF-2α through interaction with CD44, independently of oxygen. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

EFFECTS OF HYPOXIA ON GENE AND PROTEIN EXPRESSION IN THE BLUE CRAB, CALLINECTES SAPIDUS. (R829458C003)

EPA Science Inventory

Increases in hypoxic conditions are one of the major factors responsible for declines in estuarine habitat quality, yet to date there are no indicators for recognizing populations of estuarine organisms that are suffering from chronic hypoxic stress. Here we test the hypothesi...

Hypoxic Adaptation during Development: Relation to Pattern of Neurological Presentation and Cognitive Disability

ERIC Educational Resources Information Center

Kirkham, Fenella J.; Datta, Avijit K.

2006-01-01

Children with acute hypoxic-ischaemic events (e.g. stroke) and chronic neurological conditions associated with hypoxia frequently present to paediatric neurologists. Failure to adapt to hypoxia may be a common pathophysiological pathway linking a number of other conditions of childhood with cognitive deficit. There is evidence that congenital…

K(Ca)3.1 channel downregulation and impaired endothelium-derived hyperpolarization-type relaxation in pulmonary arteries from chronically hypoxic rats.

PubMed

Kroigaard, Christel; Kudryavtseva, Olga; Dalsgaard, Thomas; Wandall-Frostholm, Christine; Olesen, Søren-Peter; Simonsen, Ulf

2013-04-01

Calcium-activated potassium channels of small (K(Ca)2, SK) and intermediate (K(Ca)3.1, IK) conductance are involved in endothelium-dependent relaxation of pulmonary arteries. We hypothesized that the function and expression of K(Ca)2 and K(Ca)3.1 increase as a compensatory mechanism to counteract hypoxia-induced pulmonary hypertension in rats. For functional studies, pulmonary arteries were mounted in microvascular myographs for isometric tension recordings. The K(Ca) channel expression was evaluated by immunoblotting and quantitative PCR. Although ACh induced similar relaxations, the ACh-induced relaxations were abolished by the combined inhibition of nitric oxide synthase (by L-nitro-arginine, L-NOARG), cyclo-oxygenase (by indomethacin) and soluble guanylate cyclase (by ODQ) in pulmonary arteries from hypoxic rats, whereas 20 ± 6% (n = 8) maximal relaxation in response to ACh persisted in arteries from normoxic rats. Inhibiting Na(+),K(+)-ATPase with ouabain or blocking K(Ca)2 and K(Ca)3.1 channels reduced the persisting ACh-induced relaxation. In the presence of L-NOARG and indomethacin, a novel K(Ca)2 and K(Ca)3.1 channel activator, NS4591, induced concentration- and endothelium-dependent relaxations, which were markedly reduced in arteries from chronically hypoxic rats compared with arteries from normoxic rats. The mRNA levels of K(Ca)2.3 and K(Ca)3.1 were unaltered, whereas K(Ca)2.3 protein expression was upregulated and K(Ca)3.1 protein expression downregulated in pulmonary arteries from rats exposed to hypoxia. In conclusion, endothelium-dependent relaxation was conserved in pulmonary arteries from chronically hypoxic rats, while endothelium-derived hyperpolarization (EDH)-type relaxation was impaired in chronically hypoxic pulmonary small arteries despite upregulation of K(Ca)2.3 channels. Since impaired EDH-type relaxation was accompanied by K(Ca)3.1 channel protein downregulation, these findings suggest that K(Ca)3.1 channels are important for the maintenance of EDH-type relaxation.

Celecoxib enhances radiosensitivity of hypoxic glioblastoma cells through endoplasmic reticulum stress

PubMed Central

Suzuki, Kenshi; Gerelchuluun, Ariungerel; Hong, Zhengshan; Sun, Lue; Zenkoh, Junko; Moritake, Takashi; Tsuboi, Koji

2013-01-01

Background Refractoriness of glioblastoma multiforme (GBM) largely depends on its radioresistance. We investigated the radiosensitizing effects of celecoxib on GBM cell lines under both normoxic and hypoxic conditions. Methods Two human GBM cell lines, U87MG and U251MG, and a mouse GBM cell line, GL261, were treated with celecoxib or γ-irradiation either alone or in combination under normoxic and hypoxic conditions. Radiosensitizing effects were analyzed by clonogenic survival assays and cell growth assays and by assessing apoptosis and autophagy. Expression of apoptosis-, autophagy-, and endoplasmic reticulum (ER) stress–related genes was analyzed by immunoblotting. Results Celecoxib significantly enhanced the radiosensitivity of GBM cells under both normoxic and hypoxic conditions. In addition, combined treatment with celecoxib and γ-irradiation induced marked autophagy, particularly in hypoxic cells. The mechanism underlying the radiosensitizing effect of celecoxib was determined to be ER stress loading on GBM cells. Conclusion Celecoxib enhances the radiosensitivity of GBM cells by a mechanism that is different from cyclooxygenase-2 inhibition. Our results indicate that celecoxib may be a promising radiosensitizing drug for clinical use in patients with GBM. PMID:23658321

Inhibition of Siah2 Ubiquitin Ligase by Vitamin K3 Attenuates Chronic Myeloid Leukemia Chemo-Resistance in Hypoxic Microenvironment.

PubMed

Huang, Jixian; Lu, Ziyuan; Xiao, Yajuan; He, Bolin; Pan, Chengyun; Zhou, Xuan; Xu, Na; Liu, Xiaoli

2018-02-05

BACKGROUND A hypoxic microenvironment is associated with resistance to tyrosine kinase inhibitors (TKIs) and a poor prognosis in chronic myeloid leukemia (CML). The E3 ubiquitin ligase Siah2 plays a vital role in the regulation of hypoxia response, as well as in leukemogenesis. However, the role of Siah2 in CML resistance is unclear, and it is unknown whether vitaminK3 (a Siah2 inhibitor) can improve the chemo-sensitivity of CML cells in a hypoxic microenvironment. MATERIAL AND METHODS The expression of Siah2 was detected in CML patients (CML-CP and CML-BC), K562 cells, and K562-imatinib-resistant cells (K562-R cells). We measured the expression of PHD3, HIF-1α, and VEGF in both cell lines under normoxia and hypoxic conditions, and the degree of leukemic sensitivity to imatinib and VitaminK3 were evaluated. RESULTS Siah2 was overexpressed in CML-BC patients (n=9) as compared to CML-CP patients (n=13). Similarly, K562-imatinib-resistant cells (K562-R cells) showed a significantly higher expression of Siah2 as compared to K562 cells in a hypoxic microenvironment. Compared to normoxia, under hypoxic conditions, both cell lines had lower PHD3, higher HIF-1α, and higher VEGF expression. Additionally, Vitamin K3 (an inhibitor of Siah2) reversed these changes and promoted a higher degree of leukemic sensitivity to imatinib. CONCLUSIONS Our findings indicate that the Siah2-PHD3- HIF-1α-VEGF axis is an important hypoxic signaling pathway in a leukemic microenvironment. An inhibitor of Siah2, combined with TKIs, might be a promising therapy for relapsing and refractory CML patients.

EPR oxygen imaging and hyperpolarized 13C MRI of pyruvate metabolism as noninvasive biomarkers of tumor treatment response to a glycolysis inhibitor 3-bromopyruvate.

PubMed

Matsumoto, Shingo; Saito, Keita; Yasui, Hironobu; Morris, H Douglas; Munasinghe, Jeeva P; Lizak, Martin; Merkle, Hellmut; Ardenkjaer-Larsen, Jan Henrik; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Koretsky, Alan P; Mitchell, James B; Krishna, Murali C

2013-05-01

The hypoxic nature of tumors results in treatment resistance and poor prognosis. To spare limited oxygen for more crucial pathways, hypoxic cancerous cells suppress mitochondrial oxidative phosphorylation and promote glycolysis for energy production. Thereby, inhibition of glycolysis has the potential to overcome treatment resistance of hypoxic tumors. Here, EPR imaging was used to evaluate oxygen dependent efficacy on hypoxia-sensitive drug. The small molecule 3-bromopyruvate blocks glycolysis pathway by inhibiting hypoxia inducible enzymes and enhanced cytotoxicity of 3-bromopyruvate under hypoxic conditions has been reported in vitro. However, the efficacy of 3-bromopyruvate was substantially attenuated in hypoxic tumor regions (pO2<10 mmHg) in vivo using squamous cell carcinoma (SCCVII)-bearing mouse model. Metabolic MRI studies using hyperpolarized 13C-labeled pyruvate showed that monocarboxylate transporter-1 is the major transporter for pyruvate and the analog 3-bromopyruvate in SCCVII tumor. The discrepant results between in vitro and in vivo data were attributed to biphasic oxygen dependent expression of monocarboxylate transporter-1 in vivo. Expression of monocarboxylate transporter-1 was enhanced in moderately hypoxic (8-15 mmHg) tumor regions but down regulated in severely hypoxic (<5 mmHg) tumor regions. These results emphasize the importance of noninvasive imaging biomarkers to confirm the action of hypoxia-activated drugs. Copyright © 2012 Wiley Periodicals, Inc.

EPR oxygen imaging and hyperpolarized 13C MRI of pyruvate metabolism as non-invasive biomarkers of tumor treatment response to a glycolysis inhibitor 3-bromopyruvate

PubMed Central

Matsumoto, Shingo; Saito, Keita; Yasui, Hironobu; Morris, H. Douglas; Munasinghe, Jeeva P.; Lizak, Martin; Merkle, Hellmut; Ardenkjaer-Larsen, Jan Henrik; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Koretsky, Alan P.; Mitchell, James B.; Krishna, Murali C.

2012-01-01

The hypoxic nature of tumors results in treatment resistance and poor prognosis. To spare limited oxygen for more crucial pathways, hypoxic cancerous cells suppress mitochondrial oxidative phosphorylation, and promote glycolysis for energy production. Thereby, inhibition of glycolysis has the potential to overcome treatment resistance of hypoxic tumors. Here, EPR imaging was used to evaluate oxygen dependent efficacy on hypoxia-sensitive drug. The small molecule 3-bromopyruvate (3-BP) blocks glycolysis pathway by inhibiting hypoxia inducible enzymes, and enhanced cytotoxicity of 3-BP under hypoxic conditions has been reported in vitro. However, the efficacy of 3-BP was substantially attenuated in hypoxic tumor regions (pO2 < 10 mmHg) in vivo using squamous cell carcinoma (SCCVII)-bearing mouse model. Metabolic MRI studies using hyperpolarized 13C-labeled pyruvate showed that monocarboxylate transporter-1 (MCT1) is the major transporter for pyruvate and the analog 3-BP in SCCVII tumor. The discrepant results between in vitro and in vivo data were attributed to biphasic oxygen dependent expression of MCT1 in vivo. Expression of MCT1 was enhanced in moderately hypoxic (8–15 mmHg) tumor regions, but down regulated in severely hypoxic (< 5 mmHg) tumor regions. These results emphasize the importance of non-invasive imaging biomarkers to confirm the action of hypoxia-activated drugs. PMID:22692861

Indomethacin reduces short-circuit current and oxygen consumption in normal and chronically hypoxic rat colon.

PubMed

Saraví, Fernando D; Cincunegui, Liliana M; Saldeña, Teobaldo A; Carra, Graciela E; Ibáñez, Jorge E; Grzona, Esteban

2006-09-01

Chronic hypobaric hypoxia is a physiological environmental stressor. While its effects on most major organ systems have been extensively studied, few works have addressed hypoxia-induced changes in intestinal transport. The effects of cyclooxygenase blockade with indomethacin on short-circuit current (Isc) and oxygen consumption (QO2) of the distal colonic epithelium of control rats and rats submitted to hypoxia for 10 days at 0.52 atm were studied. Isolated mucosae were mounted in an Ussing chamber modified for measuring QO2 while preserving transepithelial vectorial transport. Amiloride was added to the mucosal hemichamber to block a sodium component of Isc present in hypoxic rats. In this condition, basal Isc did not differ between the hypoxic and the control group, but QO2 was higher in the former. Indomethacin (30 micromol/L) reduced Isc to the same extent in both groups, but QO2 reduction was larger in the hypoxic group. Pharmacological blockade of chloride secretion and a low-chloride solution abolished the indomethacin-induced reductions of Isc in both groups, and the reduction of QO2 in controls, and attenuated but did not suppress the QO2 reduction in the hypoxic group. Linear regression analysis of QO2 changes versus Isc changes yielded a significant correlation for both groups, with regression lines with the same slope, but a higher position in bypoxic animals. Results suggest that spontaneously releasedprostaglandins are equally important for maintaining colonic chloride secretion in hypoxic as in normoxic rats, but that, in the former, indomethacin has an additional effect on QO2 which is unrelated to ion transport.

Hypoxic Hypoxia at Moderate Altitudes: State of the Science

DTIC Science & Technology

2011-05-01

neuropsychological metrics (surrogate investigational end points) with actual flight task metrics (desired end points of interest) under moderate hypoxic...conditions, (2) determine efficacy of potential neuropsychological performance-enhancing agents (e.g. tyrosine supplementation) for both acute and chronic...to air hunger ; may impact training fidelity Banderet et al. (1985) 4200 and 4700 m H 27 Tyrosine enhanced performance and reduced subjective

Hypoxia as a therapy for mitochondrial disease.

PubMed

Jain, Isha H; Zazzeron, Luca; Goli, Rahul; Alexa, Kristen; Schatzman-Bone, Stephanie; Dhillon, Harveen; Goldberger, Olga; Peng, Jun; Shalem, Ophir; Sanjana, Neville E; Zhang, Feng; Goessling, Wolfram; Zapol, Warren M; Mootha, Vamsi K

2016-04-01

Defects in the mitochondrial respiratory chain (RC) underlie a spectrum of human conditions, ranging from devastating inborn errors of metabolism to aging. We performed a genome-wide Cas9-mediated screen to identify factors that are protective during RC inhibition. Our results highlight the hypoxia response, an endogenous program evolved to adapt to limited oxygen availability. Genetic or small-molecule activation of the hypoxia response is protective against mitochondrial toxicity in cultured cells and zebrafish models. Chronic hypoxia leads to a marked improvement in survival, body weight, body temperature, behavior, neuropathology, and disease biomarkers in a genetic mouse model of Leigh syndrome, the most common pediatric manifestation of mitochondrial disease. Further preclinical studies are required to assess whether hypoxic exposure can be developed into a safe and effective treatment for human diseases associated with mitochondrial dysfunction. Copyright © 2016, American Association for the Advancement of Science.

Hypoxia-response plasmid vector producing bcl-2 shRNA enhances the apoptotic cell death of mouse rectum carcinoma.

PubMed

Fujioka, Takashi; Matsunaga, Naoya; Okazaki, Hiroyuki; Koyanagi, Satoru; Ohdo, Shigehiro

2010-01-01

Hypoxia-induced gene expression frequently occurs in malignant solid tumors because they often have hypoxic areas in which circulation is compromised due to structurally disorganized blood vessels. Hypoxia-response elements (HREs) are responsible for activating gene transcription in response to hypoxia. In this study, we constructed a hypoxia-response plasmid vector producing short hairpin RNA (shRNA) against B-cell leukemia/lymphoma-2 (bcl-2), an anti-apoptotic factor. The hypoxia-response promoter was made by inserting tandem repeats of HREs upstream of cytomegalovirus (CMV) promoter (HRE-CMV). HRE-CMV shbcl-2 vector consisted of bcl-2 shRNA under the control of HRE-CMV promoter. In hypoxic mouse rectum carcinoma cells (colon-26), the production of bcl-2 shRNA driven by HRE-CMV promoter was approximately 2-fold greater than that driven by CMV promoter. A single intratumoral (i.t.) injection of 40 microg HRE-CMV shbcl-2 to colon-26 tumor-bearing mice caused apoptotic cell death, and repetitive treatment with HRE-CMV shbcl-2 (40 microg/mouse, i.t.) also significantly suppressed the growth of colon-26 tumor cells implanted in mice. Apoptotic and anti-tumor effects were not observed in tumor-bearing mice treated with CMV shbcl-2. These results reveal the ability of HRE-CMV shbcl-2 vector to suppress the expression of bcl-2 in hypoxic tumor cells and suggest the usefulness of our constructed hypoxia-response plasmid vector to treat malignant tumors. [Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.10054FP].

PI3K/Akt contributes to increased expression of Toll-like receptor 4 in macrophages exposed to hypoxic stress

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

Kim, So Young; Jeong, Eunshil; Joung, Sun Myung

2012-03-16

Highlights: Black-Right-Pointing-Pointer Hypoxic stress-induced TLR4 expression is mediated by PI3K/Akt in macrophages. Black-Right-Pointing-Pointer PI3K/Akt regulated HIF-1 activation leading to TLR4 expression. Black-Right-Pointing-Pointer p38 mitogen-activated protein kinase was not involved in TLR4 expression by hypoxic stress. Black-Right-Pointing-Pointer Sulforaphane suppressed hypoxia-mediated TLR4 expression by inhibiting PI3K/Akt. -- Abstract: Toll-like receptors (TLRs) play critical roles in triggering immune and inflammatory responses by detecting invading microbial pathogens and endogenous danger signals. Increased expression of TLR4 is implicated in aggravated inflammatory symptoms in ischemic tissue injury and chronic diseases. Results from our previous study showed that TLR4 expression was upregulated by hypoxic stress mediated bymore » hypoxia-inducible factor-1 (HIF-1) at a transcriptional level in macrophages. In this study, we further investigated the upstream signaling pathway that contributed to the increase of TLR4 expression by hypoxic stress. Either treatment with pharmacological inhibitors of PI3K and Akt or knockdown of Akt expression by siRNA blocked the increase of TLR4 mRNA and protein levels in macrophages exposed to hypoxia and CoCl{sub 2}. Phosphorylation of Akt by hypoxic stress preceded nuclear accumulation of HIF-1{alpha}. A PI3K inhibitor (LY294002) attenuated CoCl{sub 2}-induced nuclear accumulation and transcriptional activation of HIF-1{alpha}. In addition, HIF-1{alpha}-mediated upregulation of TLR4 expression was blocked by LY294002. Furthermore, sulforaphane suppressed hypoxia- and CoCl{sub 2}-induced upregulation of TLR4 mRNA and protein by inhibiting PI3K/Akt activation and the subsequent nuclear accumulation and transcriptional activation of HIF-1{alpha}. However, p38 was not involved in HIF-1{alpha} activation and TLR4 expression induced by hypoxic stress in macrophages. Collectively, our results demonstrate that PI3K/Akt contributes to hypoxic stress-induced TLR4 expression at least partly through the regulation of HIF-1 activation. These reveal a novel mechanism for regulation of TLR4 expression upon hypoxic stress and provide a therapeutic target for chronic diseases related to hypoxic stress.« less

Fetal in vivo continuous cardiovascular function during chronic hypoxia

PubMed Central

Allison, B. J.; Brain, K. L.; Niu, Y.; Kane, A. D.; Herrera, E. A.; Thakor, A. S.; Botting, K. J.; Cross, C. M.; Itani, N.; Skeffington, K. L.; Beck, C.

2016-01-01

Key points The in vivo fetal cardiovascular defence to chronic hypoxia has remained by and large an enigma because no technology has been available to induce significant and prolonged fetal hypoxia whilst recording longitudinal changes in fetal regional blood flow as the hypoxic pregnancy is developing.We introduce a new technique able to maintain chronically instrumented maternal and fetal sheep preparations under isobaric chronic hypoxia for most of gestation, beyond levels that can be achieved by high altitude and of relevance in magnitude to the human intrauterine growth‐restricted fetus.This technology permits wireless recording in free‐moving animals of longitudinal maternal and fetal cardiovascular function, including beat‐to‐beat alterations in pressure and blood flow signals in regional circulations.The relevance and utility of the technique is presented by testing the hypotheses that the fetal circulatory brain sparing response persists during chronic fetal hypoxia and that an increase in reactive oxygen species in the fetal circulation is an involved mechanism. Abstract Although the fetal cardiovascular defence to acute hypoxia and the physiology underlying it have been established for decades, how the fetal cardiovascular system responds to chronic hypoxia has been comparatively understudied. We designed and created isobaric hypoxic chambers able to maintain pregnant sheep for prolonged periods of gestation under controlled significant (10% O2) hypoxia, yielding fetal mean PaO2 levels (11.5 ± 0.6 mmHg) similar to those measured in human fetuses of hypoxic pregnancy. We also created a wireless data acquisition system able to record fetal blood flow signals in addition to fetal blood pressure and heart rate from free moving ewes as the hypoxic pregnancy is developing. We determined in vivo longitudinal changes in fetal cardiovascular function including parallel measurement of fetal carotid and femoral blood flow and oxygen and glucose delivery during the last third of gestation. The ratio of oxygen (from 2.7 ± 0.2 to 3.8 ± 0.8; P < 0.05) and of glucose (from 2.3 ± 0.1 to 3.3 ± 0.6; P < 0.05) delivery to the fetal carotid, relative to the fetal femoral circulation, increased during and shortly after the period of chronic hypoxia. In contrast, oxygen and glucose delivery remained unchanged from baseline in normoxic fetuses. Fetal plasma urate concentration increased significantly during chronic hypoxia but not during normoxia (Δ: 4.8 ± 1.6 vs. 0.5 ± 1.4 μmol l−1, P<0.05). The data support the hypotheses tested and show persisting redistribution of substrate delivery away from peripheral and towards essential circulations in the chronically hypoxic fetus, associated with increases in xanthine oxidase‐derived reactive oxygen species. PMID:26926316

Creatine and creatine pyruvate reduce hypoxia-induced effects on phrenic nerve activity in the juvenile mouse respiratory system.

PubMed

Scheer, Monika; Bischoff, Anna M; Kruzliak, Peter; Opatrilova, Radka; Bovell, Douglas; Büsselberg, Dietrich

2016-08-01

Adequate concentrations of ATP are required to preserve physiological cell functions and protect tissue from hypoxic damage. Decreased oxygen concentration results in ATP synthesis relying increasingly on the presence of phosphocreatine. The lack of ATP through hypoxic insult to neurons that generate or regulate respiratory function, would lead to the cessation of breathing (apnea). It is not clear whether creatine plays a role in maintaining respiratory phrenic nerve (PN) activity during hypoxic challenge. The aim of the study was to test the effects of exogenously applied creatine or creatine pyruvate in maintaining PN induced respiratory rhythm against the deleterious effects of severe hypoxic insult using Working Heart-Brainstem (WHB) preparations of juvenile Swiss type mice. WHB's were perfused with control perfusate or perfusate containing either creatine [100μM] or creatine pyruvate [100μM] prior to hypoxic challenge and PN activity recorded throughout. Results showed that severe hypoxic challenge resulted in an initial transient increase in PN activity, followed by a reduction in that activity leading to respiratory apnea. The results demonstrated that perfusing the WHB preparation with creatine or creatine pyruvate, significantly reduced the onset of apnea compared to control conditions, with creatine pyruvate being the more effective substance. Overall, creatine and creatine pyruvate each produced time-dependent degrees of protection against severe hypoxic-induced disturbances of PN activity. The underlying protective mechanisms are unknown and need further investigations. Copyright © 2016 Elsevier Inc. All rights reserved.

The expression of a novel stress protein '150-kDa oxygen regulated protein' in sudden infant death.

PubMed

Ikematsu, Kazuya; Tsuda, Ryouichi; Kondo, Toshikazu; Kondo, Hisayoshi; Ozawa, Kentaro; Ogawa, Satoshi; Nakasono, Ichiro

2003-03-01

The oxygen regulated protein 150-kDa (ORP-150) is only induced in hypoxic conditions. We performed an immunohistochemical and morphometrical study on the expression of ORP-150 in the brains of sudden infant death (SID) victims. The cerebral cortexes of 18 infants were used for this study. Each tissue section was incubated with anti-ORP-150 polyclonal antibodies and the number of ORP-150 positive cells was counted. In the cluster analysis, the 18 cases were classified into three groups (A-C groups). Group A was composed of six sudden infant death syndrome (SIDS) cases and its mean value of ORP-150 positive cells was 66.75+/-3.44, Group B (six severe respiratory infectious disease such as pneumonia and bronchitis including sepsis): 39.50+/-2.52 and Group C (five SIDS and one severe respiratory infectious disease): 16.00+/-2.92, respectively. These results might reflect chronic hypoxic condition before death, because ORP-150 is only induced when a hypoxic condition exist, but not acute hypoxia. And chronic hypoxic state is likely to be antecedent to SIDS. Therefore, immunohistochemical analysis of OPR-150 in the brain of SID cases may be very useful to differentiate between SIDS and acute asphyxia.

Hypoxic alligator embryos: chronic hypoxia, catecholamine levels and autonomic responses of in ovo alligators.

PubMed

Eme, John; Altimiras, Jordi; Hicks, James W; Crossley, Dane A

2011-11-01

Hypoxia is a naturally occurring environmental challenge for embryonic reptiles, and this is the first study to investigate the impact of chronic hypoxia on the in ovo development of autonomic cardiovascular regulation and circulating catecholamine levels in a reptile. We measured heart rate (f(H)) and chorioallantoic arterial blood pressure (MAP) in normoxic ('N21') and hypoxic-incubated ('H10'; 10% O(2)) American alligator embryos (Alligator mississippiensis) at 70, 80 and 90% of development. Embryonic alligator responses to adrenergic blockade with propranolol and phentolamine were very similar to previously reported responses of embryonic chicken, and demonstrated that embryonic alligator has α and β-adrenergic tone over the final third of development. However, adrenergic tone originates entirely from circulating catecholamines and is not altered by chronic hypoxic incubation, as neither cholinergic blockade with atropine nor ganglionic blockade with hexamethonium altered baseline cardiovascular variables in N21 or H10 embryos. In addition, both atropine and hexamethonium injection did not alter the generally depressive effects of acute hypoxia - bradycardia and hypotension. However, H10 embryos showed significantly higher levels of noradrenaline and adrenaline at 70% of development, as well as higher noradrenaline at 80% of development, suggesting that circulating catecholamines reach maximal levels earlier in incubation for H10 embryos, compared to N21 embryos. Chronically elevated levels of catecholamines may alter the normal balance between α and β-adrenoreceptors in H10 alligator embryos, causing chronic bradycardia and hypotension of H10 embryos measured in normoxia. Copyright © 2011 Elsevier Inc. All rights reserved.

Lipid peroxidation in neonatal mouse brain subjected to two different types of hypoxia.

PubMed

Hasegawa, K; Yoshioka, H; Sawada, T; Nishikawa, H

1991-01-01

To elucidate the role of free radicals in the pathogenesis of neonatal hypoxic encephalopathy, we determined the content of thiobarbituric acid reactants (TBARs), as an index of lipid peroxidation related with a free radical reaction, in the brains of newborn mice during hypoxia and recovery from hypoxia. Hypoxic stress was induced by 100% nitrogen gas breathing (N2 group) or 100% carbon dioxide gas breathing (CO2 group). TBARs increased with 20 minutes of hypoxia and returned to the control level during the recovery period in both groups. The increase in TBARs in the CO2 group was greater than that in the N2 group. These results may suggest that free radical reaction occurs during the hypoxic period and that CO2 hypoxia is more effective on free radical production in the newborn brain than N2 hypoxia.

pO{sub 2} Fluctuation Pattern and Cycling Hypoxia in Human Cervical Carcinoma and Melanoma Xenografts

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

Ellingsen, Christine; Ovrebo, Kirsti Marie; Galappathi, Kanthi

2012-07-15

Purpose: Blood perfusion in tumors is spatially and temporally heterogeneous, resulting in local fluctuations in tissue oxygen tension (pO{sub 2}) and tissue regions showing cycling hypoxia. In this study, we investigated whether the pO{sub 2} fluctuation pattern and the extent of cycling hypoxia differ between tumor types showing high (e.g., cervical carcinoma xenograft) and low (e.g., melanoma xenograft) fractions of connective tissue-associated blood vessels. Methods and Materials: Two cervical carcinoma lines (CK-160 and TS-415) and two melanoma lines (A-07 and R-18) transplanted into BALB/c nu/nu mice were included in the study. Tissue pO{sub 2} was measured simultaneously in two positionsmore » in each tumor by using a two-channel OxyLite fiber-optic oxygen-sensing device. The extent of acute and chronic hypoxia was assessed by combining a radiobiological and a pimonidazole-based immunohistochemical assay of tumor hypoxia. Results: The proportion of tumor regions showing pO{sub 2} fluctuations, the pO{sub 2} fluctuation frequency in these regions, and the relative amplitude of the pO{sub 2} fluctuations were significantly higher in the melanoma xenografts than in the cervical carcinoma xenografts. Cervical carcinoma and melanoma xenografts did not differ significantly in the fraction of acutely hypoxic cells or the fraction of chronically hypoxic cells. However, the ratio between fraction of acutely hypoxic cells and fraction of chronically hypoxic cells was significantly higher in melanoma than in cervical carcinoma xenografts. Conclusions: Temporal heterogeneity in blood flow and tissue pO{sub 2} in tumors may depend on tumor histology. Connective tissue surrounding microvessels may stabilize blood flow and pO{sub 2} and, thus, protect tumor tissue from cycling hypoxia.« less

Neuroprotective Role of Intermittent Hypobaric Hypoxia in Unpredictable Chronic Mild Stress Induced Depression in Rats

PubMed Central

Deep, Satayanarayan; Prasad, Dipti; Singh, Shashi Bala; Khan, Nilofar

2016-01-01

Hypoxic exposure results in several pathophysiological conditions associated with nervous system, these include acute and chronic mountain sickness, loss of memory, and high altitude cerebral edema. Previous reports have also suggested the role of hypoxia in pathogenesis of depression and related psychological conditions. On the other hand, sub lethal intermittent hypoxic exposure induces protection against future lethal hypoxia and may have beneficial effect. Therefore, the present study was designed to explore the neuroprotective role of intermittent hypobaric hypoxia (IHH) in Unpredictable Chronic Mild Stress (UCMS) induced depression like behaviour in rats. The IHH refers to the periodic exposures to hypoxic conditions interrupted by the normoxic or lesser hypoxic conditions. The current study examines the effect of IHH against UCMS induced depression, using elevated plus maze (EPM), open field test (OFT), force swim test (FST), as behavioural paradigm and related histological and molecular approaches. The data indicated the UCMS induced depression like behaviour as evident from decreased exploration activity in OFT with increased anxiety levels in EPM, and increased immobility time in the FST; whereas on providing the IHH (5000m altitude, 4hrs/day for two weeks) these behavioural changes were ameliorated. The morphological and molecular studies also validated the neuroprotective effect of IHH against UCMS induced neuronal loss and decreased neurogenesis. Here, we also explored the role of Brain-Derived Neurotrophic Factor (BDNF) in anticipatory action of IHH against detrimental effect of UCMS as upon blocking of BDNF-TrkB signalling the beneficial effect of IHH was nullified. Taken together, the findings of our study demonstrate that the intermittent hypoxia has a therapeutic potential similar to an antidepressant in animal model of depression and could be developed as a preventive therapeutic option against this pathophysiological state. PMID:26901349

Curtailed respiration by repeated vs. isolated hypoxia in maturing piglets is unrelated to NTS ME or SP levels.

PubMed

Waters, K A; Laferrière, A; Paquette, J; Goodyer, C; Moss, I R

1997-08-01

In early development, respiratory disorders can produce recurring hypoxic episodes during sleep. To examine possible effects of daily repeated vs. isolated hypoxic hypoxia, cardiorespiratory functions and central, respiratory-related neuromodulator levels in 21- to 32-day-old, chronically instrumented, unsedated piglets were compared between a fifth sequential daily hypoxia and an isolated hypoxia (10% O2-90% N2 for 30 min). Diaphragmatic electromyographic activity, heart rate and arterial pressure, and pH and gas tensions were measured. In vivo microdialysis, via chronically implanted guides, served to sample interstitial substance P (SP) and methionine-enkephalin (ME) at the level of the respiratory-related nucleus tractus solitarii (NTS). Compared with an isolated hypoxia, repeated hypoxia resulted in 1) lower respiratory frequency (f), ventilation equivalent, and arterial pH, higher arterial PO2 during hypoxia, and lower f in recovery from hypoxia; and 2) increased SP concentrations but no change in ME concentrations. We conclude that, in these maturing swine, repeated vs. isolated hypoxic exposure curtails respiratory responses to hypoxia by a mechanism(s) unrelated to SP or ME levels at the NTS.

Activation of DOR attenuates anoxic K+ derangement via inhibition of Na+ entry in mouse cortex.

PubMed

Chao, Dongman; Bazzy-Asaad, Alia; Balboni, Gianfranco; Salvadori, Severo; Xia, Ying

2008-09-01

We have recently found that in the mouse cortex, activation of delta-opioid receptor (DOR) attenuates the disruption of K(+) homeostasis induced by hypoxia or oxygen-glucose deprivation. This novel observation suggests that DOR may protect neurons from hypoxic/ischemic insults via the regulation of K(+) homeostasis because the disruption of K(+) homeostasis plays a critical role in neuronal injury under hypoxic/ischemic stress. The present study was performed to explore the ionic mechanism underlying the DOR-induced neuroprotection. Because anoxia causes Na(+) influx and thus stimulates K(+) leakage, we investigated whether DOR protects the cortex from anoxic K(+) derangement by targeting the Na(+)-based K(+) leakage. By using K(+)-sensitive microelectrodes in mouse cortical slices, we showed that 1) lowering Na(+) concentration and substituting with impermeable N-methyl-D-glucamine caused a concentration-dependent attenuation of anoxic K(+) derangement; 2) lowering Na(+) concentration by substituting with permeable Li(+) tended to potentiate the anoxic K(+) derangement; and 3) the DOR-induced protection against the anoxic K(+) responses was largely abolished by low-Na(+) perfusion irrespective of the substituted cation. We conclude that external Na(+) concentration greatly influences anoxic K(+) derangement and that DOR activation likely attenuates anoxic K(+) derangement induced by the Na(+)-activated mechanisms in the cortex.

Intratumoral oxygen gradients mediate sarcoma cell invasion

PubMed Central

Lewis, Daniel M.; Park, Kyung Min; Tang, Vitor; Xu, Yu; Pak, Koreana; Eisinger-Mathason, T. S. Karin; Simon, M. Celeste; Gerecht, Sharon

2016-01-01

Hypoxia is a critical factor in the progression and metastasis of many cancers, including soft tissue sarcomas. Frequently, oxygen (O2) gradients develop in tumors as they grow beyond their vascular supply, leading to heterogeneous areas of O2 depletion. Here, we report the impact of hypoxic O2 gradients on sarcoma cell invasion and migration. O2 gradient measurements showed that large sarcoma mouse tumors (>300 mm3) contain a severely hypoxic core [≤0.1% partial pressure of O2 (pO2)] whereas smaller tumors possessed hypoxic gradients throughout the tumor mass (0.1–6% pO2). To analyze tumor invasion, we used O2-controllable hydrogels to recreate the physiopathological O2 levels in vitro. Small tumor grafts encapsulated in the hydrogels revealed increased invasion that was both faster and extended over a longer distance in the hypoxic hydrogels compared with nonhypoxic hydrogels. To model the effect of the O2 gradient accurately, we examined individual sarcoma cells embedded in the O2-controllable hydrogel. We observed that hypoxic gradients guide sarcoma cell motility and matrix remodeling through hypoxia-inducible factor-1α (HIF-1α) activation. We further found that in the hypoxic gradient, individual cells migrate more quickly, across longer distances, and in the direction of increasing O2 tension. Treatment with minoxidil, an inhibitor of hypoxia-induced sarcoma metastasis, abrogated cell migration and matrix remodeling in the hypoxic gradient. Overall, we show that O2 acts as a 3D physicotactic agent during sarcoma tumor invasion and propose the O2-controllable hydrogels as a predictive system to study early stages of the metastatic process and therapeutic targets. PMID:27486245

Intratumoral oxygen gradients mediate sarcoma cell invasion.

PubMed

Lewis, Daniel M; Park, Kyung Min; Tang, Vitor; Xu, Yu; Pak, Koreana; Eisinger-Mathason, T S Karin; Simon, M Celeste; Gerecht, Sharon

2016-08-16

Hypoxia is a critical factor in the progression and metastasis of many cancers, including soft tissue sarcomas. Frequently, oxygen (O2) gradients develop in tumors as they grow beyond their vascular supply, leading to heterogeneous areas of O2 depletion. Here, we report the impact of hypoxic O2 gradients on sarcoma cell invasion and migration. O2 gradient measurements showed that large sarcoma mouse tumors (>300 mm(3)) contain a severely hypoxic core [≤0.1% partial pressure of O2 (pO2)] whereas smaller tumors possessed hypoxic gradients throughout the tumor mass (0.1-6% pO2). To analyze tumor invasion, we used O2-controllable hydrogels to recreate the physiopathological O2 levels in vitro. Small tumor grafts encapsulated in the hydrogels revealed increased invasion that was both faster and extended over a longer distance in the hypoxic hydrogels compared with nonhypoxic hydrogels. To model the effect of the O2 gradient accurately, we examined individual sarcoma cells embedded in the O2-controllable hydrogel. We observed that hypoxic gradients guide sarcoma cell motility and matrix remodeling through hypoxia-inducible factor-1α (HIF-1α) activation. We further found that in the hypoxic gradient, individual cells migrate more quickly, across longer distances, and in the direction of increasing O2 tension. Treatment with minoxidil, an inhibitor of hypoxia-induced sarcoma metastasis, abrogated cell migration and matrix remodeling in the hypoxic gradient. Overall, we show that O2 acts as a 3D physicotactic agent during sarcoma tumor invasion and propose the O2-controllable hydrogels as a predictive system to study early stages of the metastatic process and therapeutic targets.

Progenitor-like cells derived from mouse kidney protect against renal fibrosis in a remnant kidney model via decreased endothelial mesenchymal transition.

PubMed

Chen, C L; Chou, K J; Fang, H C; Hsu, C Y; Huang, W C; Huang, C W; Huang, C K; Chen, H Y; Lee, P T

2015-12-02

Pathophysiological changes associated with chronic kidney disease impair angiogenic processes and increase renal fibrosis. Progenitor-like cells derived from adult kidney have been previously used to promote regeneration in acute kidney injury, even though it remained unclear whether the cells could be beneficial in chronic kidney disease (CKD). In this study, we established a CKD model by five-sixths nephrectomy and mouse kidney progenitor-like cells (MKPCs) were intravenously administered weekly for 5 weeks after establishing CKD. We examined the impact of MKPCs on the progression of renal fibrosis and the potential of MKPCs to preserve the angiogenic process and prevent endothelial mesenchymal transition in vivo and in vitro. Our results demonstrate that the MKPCs delayed interstitial fibrosis and the progression of glomerular sclerosis and ameliorated the decline of kidney function. At 17 weeks, the treated mice exhibited lower blood pressures, higher hematocrit levels, and larger kidney sizes than the control mice. In addition, the MKPC treatment prolonged the survival of the mice with chronic kidney injuries. We observed a decreased recruitment of macrophages and myofibroblasts in the interstitium and the increased tubular proliferation. Notably, MKPC both decreased the level of vascular rarefaction and prevented endothelial mesenchymal transition (EndoMT) in the remnant kidneys. Moreover, the conditioned medium from the MKPCs ameliorated endothelial cell death under hypoxic culture conditions and prevented TGF-β-induced EndoMT through downregulation of phosphorylated Smad 3 in vitro. MKPCs may be a beneficial treatment for kidney diseases characterized by progressive renal fibrosis. The enhanced preservation of angiogenic processes following MKPC injections may be associated with decreased fibrosis in the remnant kidney. These findings provide further understanding of the mechanisms involved in these processes and will help develop new cell-based therapeutic strategies for regenerative medicine in renal fibrosis.

Behavior of platinum(iv) complexes in models of tumor hypoxia: cytotoxicity, compound distribution and accumulation.

PubMed

Schreiber-Brynzak, Ekaterina; Pichler, Verena; Heffeter, Petra; Hanson, Buck; Theiner, Sarah; Lichtscheidl-Schultz, Irene; Kornauth, Christoph; Bamonti, Luca; Dhery, Vineet; Groza, Diana; Berry, David; Berger, Walter; Galanski, Markus; Jakupec, Michael A; Keppler, Bernhard K

2016-04-01

Hypoxia in solid tumors remains a challenge for conventional cancer therapeutics. As a source for resistance, metastasis development and drug bioprocessing, it influences treatment results and disease outcome. Bioreductive platinum(iv) prodrugs might be advantageous over conventional metal-based therapeutics, as biotransformation in a reductive milieu, such as under hypoxia, is required for drug activation. This study deals with a two-step screening of experimental platinum(iv) prodrugs with different rates of reduction and lipophilicity with the aim of identifying the most appropriate compounds for further investigations. In the first step, the cytotoxicity of all compounds was compared in hypoxic multicellular spheroids and monolayer culture using a set of cancer cell lines with different sensitivities to platinum(ii) compounds. Secondly, two selected compounds were tested in hypoxic xenografts in SCID mouse models in comparison to satraplatin, and, additionally, (LA)-ICP-MS-based accumulation and distribution studies were performed for these compounds in hypoxic spheroids and xenografts. Our findings suggest that, while cellular uptake and cytotoxicity strongly correlate with lipophilicity, cytotoxicity under hypoxia compared to non-hypoxic conditions and antitumor activity of platinum(iv) prodrugs are dependent on their rate of reduction.

Biological properties and response to x-rays of first-generation transplants of spontaneous mammary carcinomas in C3H mice.

PubMed

Fowler, J F; Sheldon, P W; Begg, A C; Hill, S A; Smith, A M

1975-05-01

First-generation transplants of spontaneous mouse mammary carcinomas have been used extensively for radiobiological investigations of fractionated irradiation schedules, r.b.e. of fast neutrons and effectiveness of radiosensitizers, as reported elsewhere. The present work investigates the growth characteristics of the tumours; the criteria for the choice of end-points used in the definition of 'local control' of irradiated tumours; the reason for a decrease of 30 per cent in X-ray dose required to control tumours in females as compared with male mice; the proportion of hypoxic cells and its variation with time (reoxygenation) after a single dose of 1500 rad of X-rays; and the repair capacity of tumour cells within 24 hours after a substantial first dose of X-rays. Evidence is presented that the male-female difference was due to a higher proportion of hypoxic cells in tumours in male than in female mice. The repair of sub-lethal injury in tumour cells made hypoxic was slightly less than in skin made hypoxic but not significantly so. In the two-dose experiments on clamped tumours, no evidence of induced synchrony was found.

Important role of PLC-γ1 in hypoxic increase in intracellular calcium in pulmonary arterial smooth muscle cells

PubMed Central

Yadav, Vishal R.; Song, Tengyao; Joseph, Leroy; Mei, Lin; Zheng, Yun-Min

2013-01-01

An increase in intracellular calcium concentration ([Ca2+]i) in pulmonary arterial smooth muscle cells (PASMCs) induces hypoxic cellular responses in the lungs; however, the underlying molecular mechanisms remain incompletely understood. We report, for the first time, that acute hypoxia significantly enhances phospholipase C (PLC) activity in mouse resistance pulmonary arteries (PAs), but not in mesenteric arteries. Western blot analysis and immunofluorescence staining reveal the expression of PLC-γ1 protein in PAs and PASMCs, respectively. The activity of PLC-γ1 is also augmented in PASMCs following hypoxia. Lentiviral shRNA-mediated gene knockdown of mitochondrial complex III Rieske iron-sulfur protein (RISP) to inhibit reactive oxygen species (ROS) production prevents hypoxia from increasing PLC-γ1 activity in PASMCs. Myxothiazol, a mitochondrial complex III inhibitor, reduces the hypoxic response as well. The PLC inhibitor U73122, but not its inactive analog U73433, attenuates the hypoxic vasoconstriction in PAs and hypoxic increase in [Ca2+]i in PASMCs. PLC-γ1 knockdown suppresses its protein expression and the hypoxic increase in [Ca2+]i. Hypoxia remarkably increases inositol 1,4,5-trisphosphate (IP3) production, which is blocked by U73122. The IP3 receptor (IP3R) antagonist 2-aminoethoxydiphenyl borate (2-APB) or xestospongin-C inhibits the hypoxic increase in [Ca2+]i. PLC-γ1 knockdown or U73122 reduces H2O2-induced increase in [Ca2+]i in PASMCs and contraction in PAs. 2-APB and xestospongin-C produce similar inhibitory effects. In conclusion, our findings provide novel evidence that hypoxia activates PLC-γ1 by increasing RISP-dependent mitochondrial ROS production in the complex III, which causes IP3 production, IP3R opening, and Ca2+ release, playing an important role in hypoxic Ca2+ and contractile responses in PASMCs. PMID:23204067

Phenotypic plasticity in the common snapping turtle (Chelydra serpentina): long-term physiological effects of chronic hypoxia during embryonic development.

PubMed

Wearing, Oliver H; Eme, John; Rhen, Turk; Crossley, Dane A

2016-01-15

Studies of embryonic and hatchling reptiles have revealed marked plasticity in morphology, metabolism, and cardiovascular function following chronic hypoxic incubation. However, the long-term effects of chronic hypoxia have not yet been investigated in these animals. The aim of this study was to determine growth and postprandial O2 consumption (V̇o2), heart rate (fH), and mean arterial pressure (Pm, in kPa) of common snapping turtles (Chelydra serpentina) that were incubated as embryos in chronic hypoxia (10% O2, H10) or normoxia (21% O2, N21). We hypothesized that hypoxic development would modify posthatching body mass, metabolic rate, and cardiovascular physiology in juvenile snapping turtles. Yearling H10 turtles were significantly smaller than yearling N21 turtles, both of which were raised posthatching in normoxic, common garden conditions. Measurement of postprandial cardiovascular parameters and O2 consumption were conducted in size-matched three-year-old H10 and N21 turtles. Both before and 12 h after feeding, H10 turtles had a significantly lower fH compared with N21 turtles. In addition, V̇o2 was significantly elevated in H10 animals compared with N21 animals 12 h after feeding, and peak postprandial V̇o2 occurred earlier in H10 animals. Pm of three-year-old turtles was not affected by feeding or hypoxic embryonic incubation. Our findings demonstrate that physiological impacts of developmental hypoxia on embryonic reptiles continue into juvenile life. Copyright © 2016 the American Physiological Society.

Long-term regulation of carotid body function: acclimatization and adaptation--invited article.

PubMed

Prabhakar, N R; Peng, Y-J; Kumar, G K; Nanduri, J; Di Giulio, C; Lahiri, Sukhamay

2009-01-01

Physiological responses to hypoxia either continuous (CH) or intermittent (IH) depend on the O(2)-sensing ability of the peripheral arterial chemoreceptors, especially the carotid bodies, and the ensuing reflexes play important roles in maintaining homeostasis. The purpose of this article is to summarize the effects of CH and IH on carotid body function and the underlying mechanisms. CH increases baseline carotid body activity and sensitizes the response to acute hypoxia. These effects are associated with hyperplasia of glomus cells and neovascularization. Enhanced hypoxic sensitivity is due to alterations in ion current densities as well as changes in neurotransmitter dynamics and recruitment of additional neuromodulators (endothelin-1, ET-1) in glomus cells. Morphological alterations are in part due to up-regulation of growth factors (e.g. VEGF). Hypoxia-inducible factor-1 (HIF-1), a transcriptional activator might underlie the remodeling of carotid body structure and function by CH. Chronic IH, on the other hand, is associated with recurrent apneas in adults and premature infants. Two major effects of chronic IH on the adult carotid body are sensitization of the hypoxic sensory response and long-lasting increase in baseline activity i.e., sensory long-term facilitation (LTF) which involve reactive oxygen species (ROS) and HIF-1. In neonates, chronic IH leads to sensitization of the hypoxic response but does not induce sensory LTF. Chronic IH-induced sensitization of the carotid body response to hypoxia increases the likelihood of unstable breathing perpetuating in more number of apneas, whereas sensory LTF may contribute to increased sympathetic tone and systemic hypertension associated with recurrent apneas.

Late gestational hypoxia and a postnatal high salt diet programs endothelial dysfunction and arterial stiffness in adult mouse offspring.

PubMed

Walton, Sarah L; Singh, Reetu R; Tan, Tiffany; Paravicini, Tamara M; Moritz, Karen M

2016-03-01

Gestational hypoxia and high dietary salt intake have both been associated with impaired vascular function in adulthood. Using a mouse model of prenatal hypoxia, we examined whether a chronic high salt diet had an additive effect in promoting vascular dysfunction in offspring. Pregnant CD1 dams were placed in a hypoxic chamber (12% O2) or housed under normal conditions (21% O2) from embryonic day 14.5 until birth. Gestational hypoxia resulted in a reduced body weight for both male and female offspring at birth. This restriction in body weight persisted until weaning, after which the animals underwent catch-up growth. At 10 weeks of age, a subset of offspring was placed on a high salt diet (5% NaCl). Pressurized myography of mesenteric resistance arteries at 12 months of age showed that both male and female offspring exposed to maternal hypoxia had significantly impaired endothelial function, as demonstrated by impaired vasodilatation to ACh but not sodium nitroprusside. Endothelial dysfunction caused by prenatal hypoxia was not exacerbated by postnatal consumption of a high salt diet. Prenatal hypoxia increased microvascular stiffness in male offspring. The combination of prenatal hypoxia and a postnatal high salt diet caused a leftward shift in the stress-strain relationship in both sexes. Histopathological analysis of aortic sections revealed a loss of elastin integrity and increased collagen, consistent with increased vascular stiffness. These results demonstrate that prenatal hypoxia programs endothelial dysfunction in both sexes. A chronic high salt diet in postnatal life had an additive deleterious effect on vascular mechanics and structural characteristics in both sexes. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Oxygen-sensitive regulation and neuroprotective effects of growth hormone-dependent growth factors during early postnatal development.

PubMed

Jung, Susan; Boie, Gudrun; Doerr, Helmuth-Guenther; Trollmann, Regina

2017-04-01

Perinatal hypoxia severely disrupts metabolic and somatotrophic development, as well as cerebral maturational programs. Hypoxia-inducible transcription factors (HIFs) represent the most important endogenous adaptive mechanisms to hypoxia, activating a broad spectrum of growth factors that contribute to cell survival and energy homeostasis. To analyze effects of systemic hypoxia and growth hormone (GH) therapy (rhGH) on HIF-dependent growth factors during early postnatal development, we compared protein (using ELISA) and mRNA (using quantitative RT PCR) levels of growth factors in plasma and brain between normoxic and hypoxic mice (8% O 2 , 6 h; postnatal day 7 , P7) at P14. Exposure to hypoxia led to reduced body weight ( P < 0.001) and length ( P < 0.04) compared with controls and was associated with significantly reduced plasma levels of mouse GH ( P < 0.01) and IGF-1 ( P < 0.01). RhGH abrogated these hypoxia-induced changes of the GH/IGF-1 axis associated with normalization of weight and length gain until P14 compared with controls. In addition, rhGH treatment increased cerebral IGF-1, IGF-2, IGFBP-2, and erythropoietin mRNA levels, resulting in significantly reduced apoptotic cell death in the hypoxic, developing mouse brain. These data indicate that rhGH may functionally restore hypoxia-induced systemic dysregulation of the GH/IGF-1 axis and induce upregulation of neuroprotective, HIF-dependent growth factors in the hypoxic developing brain. Copyright © 2017 the American Physiological Society.

Priming of the Cells: Hypoxic Preconditioning for Stem Cell Therapy.

PubMed

Wei, Zheng Z; Zhu, Yan-Bing; Zhang, James Y; McCrary, Myles R; Wang, Song; Zhang, Yong-Bo; Yu, Shan-Ping; Wei, Ling

2017-10-05

Stem cell-based therapies are promising in regenerative medicine for protecting and repairing damaged brain tissues after injury or in the context of chronic diseases. Hypoxia can induce physiological and pathological responses. A hypoxic insult might act as a double-edged sword, it induces cell death and brain damage, but on the other hand, sublethal hypoxia can trigger an adaptation response called hypoxic preconditioning or hypoxic tolerance that is of immense importance for the survival of cells and tissues. This review was based on articles published in PubMed databases up to August 16, 2017, with the following keywords: "stem cells," "hypoxic preconditioning," "ischemic preconditioning," and "cell transplantation." Original articles and critical reviews on the topics were selected. Hypoxic preconditioning has been investigated as a primary endogenous protective mechanism and possible treatment against ischemic injuries. Many cellular and molecular mechanisms underlying the protective effects of hypoxic preconditioning have been identified. In cell transplantation therapy, hypoxic pretreatment of stem cells and neural progenitors markedly increases the survival and regenerative capabilities of these cells in the host environment, leading to enhanced therapeutic effects in various disease models. Regenerative treatments can mobilize endogenous stem cells for neurogenesis and angiogenesis in the adult brain. Furthermore, transplantation of stem cells/neural progenitors achieves therapeutic benefits via cell replacement and/or increased trophic support. Combinatorial approaches of cell-based therapy with additional strategies such as neuroprotective protocols, anti-inflammatory treatment, and rehabilitation therapy can significantly improve therapeutic benefits. In this review, we will discuss the recent progress regarding cell types and applications in regenerative medicine as well as future applications.

Is (18)F-FDG a surrogate tracer to measure tumor hypoxia? Comparison with the hypoxic tracer (14)C-EF3 in animal tumor models.

PubMed

Christian, Nicolas; Deheneffe, Stéphanie; Bol, Anne; De Bast, Marc; Labar, Daniel; Lee, John A; Grégoire, Vincent

2010-11-01

Fluorodeoxyglucose (FDG) has been reported as a surrogate tracer to measure tumor hypoxia with positron emission tomography (PET). The hypothesis is that there is an increased uptake of FDG under hypoxic conditions secondary to enhanced glycolysis, compensating the hypoxia-induced loss of cellular energy production. Several studies have already addressed this issue, some with conflicting results. This study aimed to compare the tracers (14)C-EF3 and (18)F-FDG to detect hypoxia in mouse tumor models. C3H, tumor-bearing mice (FSAII and SCCVII tumors) were injected iv with (14)C-EF3, and 1h later with (18)F-FDG. Using a specifically designed immobilization device with fiducial markers, PET (Mosaic®, Philips) images were acquired 1h after the FDG injection. After imaging, the device containing mouse was frozen, transversally sliced and imaged with autoradiography (AR) (FLA-5100, Fujifilm) to obtain high resolution images of the (18)F-FDG distribution within the tumor area. After a 48-h delay allowing for (18)F decay a second AR was performed to image (14)C-EF3 distribution. AR images were aligned to reconstruct the full 3D tumor volume, and were compared with the PET images. Image segmentation with threshold-based methods was applied on both AR and PET images to derive various tracer activity volumes. The matching index DSI (dice similarity index) was then computed. The comparison was performed under normoxic (ambient air, FSAII: n=4, SCCVII, n=5) and under hypoxic conditions (10% O(2) breathing, SCCVII: n=4). On AR, under both ambient air and hypoxic conditions, there was a decreasing similarity between (14)C-EF3 and FDG with higher activity sub-volumes. Under normoxic conditions, when comparing the 10% of tumor voxels with the highest (18)F-FDG or (14)C-EF3 activity, a DSI of 0.24 and 0.20 was found for FSAII and SCCVII, respectively. Under hypoxic conditions, a DSI of 0.36 was observed for SCCVII tumors. When comparing the (14)C-EF3 distribution in AR with the corresponding (18)F-FDG-PET images, the DSI reached values of 0.26, 0.22 and 0.21 for FSAII and SCCVII under normoxia and SCCVII under hypoxia, respectively. This study showed that FDG is not a good surrogate tracer for tumor hypoxia under either ambient or hypoxic conditions. Only specific hypoxia tracers should be used to measure tumor hypoxia. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Carbon dioxide narcosis due to inappropriate oxygen delivery: a case report.

PubMed

Herren, Thomas; Achermann, Eva; Hegi, Thomas; Reber, Adrian; Stäubli, Max

2017-07-28

Oxygen delivery to patients with chronic obstructive pulmonary disease may be challenging because of their potential hypoxic ventilatory drive. However, some oxygen delivery systems such as non-rebreathing face masks with an oxygen reservoir bag require high oxygen flow for adequate oxygenation and to avoid carbon dioxide rebreathing. A 72-year-old Caucasian man with severe chronic obstructive pulmonary disease was admitted to the emergency department because of worsening dyspnea and an oxygen saturation of 81% measured by pulse oximetry. Oxygen was administered using a non-rebreathing mask with an oxygen reservoir bag attached. For fear of removing the hypoxic stimulus to respiration the oxygen flow was inappropriately limited to 4L/minute. The patient developed carbon dioxide narcosis and had to be intubated and mechanically ventilated. Non-rebreathing masks with oxygen reservoir bags must be fed with an oxygen flow exceeding the patient's minute ventilation (>6-10 L/minute.). If not, the amount of oxygen delivered will be too small to effectively increase the arterial oxygen saturation. Moreover, the risk of carbon dioxide rebreathing dramatically increases if the flow of oxygen to a non-rebreathing mask is lower than the minute ventilation, especially in patients with chronic obstructive pulmonary disease and low tidal volumes. Non-rebreathing masks (with oxygen reservoir bags) must be used cautiously by experienced medical staff and with an appropriately high oxygen flow of 10-15 L/minute. Nevertheless, arterial blood gases must be analyzed regularly for early detection of a rise in partial pressure of carbon dioxide in arterial blood in patients with chronic obstructive pulmonary disease and a hypoxic ventilatory drive. These patients are more safely managed using a nasal cannula with an oxygen flow of 1-2L/minute or a simple face mask with an oxygen flow of 5L/minute.

Priming of the Cells: Hypoxic Preconditioning for Stem Cell Therapy

PubMed Central

Wei, Zheng Z; Zhu, Yan-Bing; Zhang, James Y; McCrary, Myles R; Wang, Song; Zhang, Yong-Bo; Yu, Shan-Ping; Wei, Ling

2017-01-01

Objective: Stem cell-based therapies are promising in regenerative medicine for protecting and repairing damaged brain tissues after injury or in the context of chronic diseases. Hypoxia can induce physiological and pathological responses. A hypoxic insult might act as a double-edged sword, it induces cell death and brain damage, but on the other hand, sublethal hypoxia can trigger an adaptation response called hypoxic preconditioning or hypoxic tolerance that is of immense importance for the survival of cells and tissues. Data Sources: This review was based on articles published in PubMed databases up to August 16, 2017, with the following keywords: “stem cells,” “hypoxic preconditioning,” “ischemic preconditioning,” and “cell transplantation.” Study Selection: Original articles and critical reviews on the topics were selected. Results: Hypoxic preconditioning has been investigated as a primary endogenous protective mechanism and possible treatment against ischemic injuries. Many cellular and molecular mechanisms underlying the protective effects of hypoxic preconditioning have been identified. Conclusions: In cell transplantation therapy, hypoxic pretreatment of stem cells and neural progenitors markedly increases the survival and regenerative capabilities of these cells in the host environment, leading to enhanced therapeutic effects in various disease models. Regenerative treatments can mobilize endogenous stem cells for neurogenesis and angiogenesis in the adult brain. Furthermore, transplantation of stem cells/neural progenitors achieves therapeutic benefits via cell replacement and/or increased trophic support. Combinatorial approaches of cell-based therapy with additional strategies such as neuroprotective protocols, anti-inflammatory treatment, and rehabilitation therapy can significantly improve therapeutic benefits. In this review, we will discuss the recent progress regarding cell types and applications in regenerative medicine as well as future applications. PMID:28937044

Hepatocytes Determine the Hypoxic Microenvironment and Radiosensitivity of Colorectal Cancer Cells Through Production of Nitric Oxide That Targets Mitochondrial Respiration

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

Jiang, Heng; Verovski, Valeri N.; Leonard, Wim

2013-03-01

Purpose: To determine whether host hepatocytes may reverse hypoxic radioresistance through nitric oxide (NO)-induced oxygen sparing, in a model relevant to colorectal cancer (CRC) liver metastases. Methods and Materials: Hepatocytes and a panel of CRC cells were incubated in a tissue-mimetic coculture system with diffusion-limited oxygenation, and oxygen levels were monitored by an oxygen-sensing fluorescence probe. To activate endogenous NO production, cocultures were exposed to a cytokine mixture, and the expression of inducible nitric oxide synthase was analyzed by reverse transcription–polymerase chain reaction, Western blotting, and NO/nitrite production. The mitochondrial targets of NO were examined by enzymatic activity. To assessmore » hypoxic radioresponse, cocultures were irradiated and reseeded for colonies. Results: Resting hepatocytes consumed 10-40 times more oxygen than mouse CT26 and human DLD-1, HT29, HCT116, and SW480 CRC cells, and thus seemed to be the major effectors of hypoxic conditioning. As a result, hepatocytes caused uniform radioprotection of tumor cells at a 1:1 ratio. Conversely, NO-producing hepatocytes radiosensitized all CRC cell lines more than 1.5-fold, similar to the effect of selective mitochondrial inhibitors. The radiosensitizing effect was associated with a respiratory self-arrest of hepatocytes at the level of aconitase and complex II, which resulted in profound reoxygenation of tumor cells through oxygen sparing. Nitric oxide–producing hepatocytes were at least 10 times more active than NO-producing macrophages to reverse hypoxia-induced radioresistance. Conclusions: Hepatocytes were the major determinants of the hypoxic microenvironment and radioresponse of CRC cells in our model of metabolic hypoxia. We provide evidence that reoxygenation and radiosensitization of hypoxic CRC cells can be achieved through oxygen sparing induced by endogenous NO production in host hepatocytes.« less

Wound management with compression therapy and topical hemoglobin solution in a patient with Budd-Chiari Syndrome.

PubMed

Babadagi-Hardt, Zeynep; Engels, Peter; Kanya, Susanne

2014-03-31

Although the underlying primary cause of chronic wounds may vary, a common etiology of this is a hypoxic or ischemic status of the affected tissue of the lower extremities. In particular, for rare diseases associated with disturbed blood flow a correlation between cause and effect is often diagnosed inappropriately. As a consequence, chronic wounds may develop and persist for years. We present a case of a patient with chronic venous insufficiency due to an occlusion of the inferior caval vein. Initially, a Budd-Chiari syndrome was diagnosed which is a thrombotic obstruction of the hepatic venous outflow. In addition, the patient developed an obstruction of the inferior caval vein and subsequently a chronic venous insufficiency. As a consequence, chronic leg ulcers developed with a history of more than 7 years. Various wound care approaches were performed without success in wound closure. Finally, a combination of compression therapy and topical application of a hemoglobin solution successfully led to fast and persistent wound closure. Chronic ulcers of the lower limb such as venous leg ulcers, even for patients with rare disorders like Budd-Chiari syndrome, are associated with oxygen supply disturbances resulting in a hypoxic status of the affected tissue. Therefore, an adequate oxygen supply to chronic wounds plays a pivotal role in successful wound healing. Compression therapy in combination with enhancement of the local oxygen supply by topically applied hemoglobin showed marked improvement of wound healing in the presented patient.

Neuroprotective Interventions: Is It Too Late?

PubMed Central

Jenkins, Dorothea; Chang, Eugene; Singh, Inderjit

2013-01-01

In most cases of neonatal hypoxic-ischemic encephalopathy, the exact timing of the hypoxic-ischemic event is unknown, and we have few reliable biomarkers to precisely identify the phase of injury or recovery in an individual patient. However, it is becoming increasingly clear that for neuroprotection in neonates to succeed, an understanding of the phase of injury is important to ascertain. In addition, in utero antecedents of chronic hypoxia, hypoxic preconditioning, intrauterine infection, and fetal gender may change the expected time course of injury. Neuroprotective interventions, such as hypothermia and N-acetylcysteine, currently have efficacy in human and animal studies only if instituted early in the inflammatory cascade. While these cascades are currently being investigated, molecular mechanisms of recovery have received little attention and may ultimately reveal a window for therapeutic intervention that is much longer than current paradigms. PMID:19745093

Differential responsiveness in VEGF receptor subtypes to hypoxic stress in various tissues of plateau animals.

PubMed

Xie, Hui-Chun; Li, Jin-Gang; He, Jian-Ping

2017-05-04

With hypoxic stress, hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) are elevated and their responses are altered in skeletal muscles of plateau animals [China Qinghai-Tibetan plateau pikas (Ochotona curzoniae)] as compared with control animals [normal lowland Sprague-Dawley (SD) rats]. The results indicate that HIF-1alpha and VEGF are engaged in physiological functions under hypoxic environment. The purpose of the current study was to examine the protein levels of VEGF receptor subtypes (VEGFRs: VEGFR-1, VEGFR-2 and VEGFR-3) in the end organs, namely skeletal muscle, heart and lung in response to hypoxic stress. ELISA and Western blot analysis were employed to determine HIF-1alpha and the protein expression of VEGFRs in control animals and plateau pikas. We further blocked HIF-1alpha signal to determine if HIF-1alpha regulates alternations in VEGFRs in those tissues. We hypothesized that responsiveness of VEGFRs in the major end organs of plateau animals is differential with insult of hypoxic stress and is modulated by low oxygen sensitive HIF-1alpha. Our results show that hypoxic stress induced by exposure of lower O(2) for 6 h significantly increased the levels of VEGFR-2 in skeletal muscle, heart and lung and the increases were amplified in plateau pikas. Our results also demonstrate that hypoxic stress enhanced VEGFR-3 in lungs of plateau animals. Nonetheless, no significant alternations in VEGFR-1 were observed in those tissues with hypoxic stress. Moreover, we observed decreases of VEGFR-2 in skeletal muscle, heart and lung; and decreases of VEGFR-3 in lung following HIF-1alpha inhibition. Overall, our findings suggest that in plateau animals 1) responsiveness of VEGFRs is different under hypoxic environment; 2) amplified VEGFR-2 response appears in skeletal muscle, heart and lung, and enhanced VEGFR-3 response is mainly observed in lung; 3) HIF-1alpha plays a regulatory role in the levels of VEGFRs. Our results provide the underlying cellular and molecular mechanisms responsible for hypoxic environment in plateau animals, having an impact on research of physiological and ecological adaptive responses to acute or chronic hypoxic stress in humans who living at high attitude and who live at a normal sea level but suffer from hypoxic disorders.

Chronic hypoxic incubation blunts a cardiovascular reflex loop in embryonic American alligator (Alligator mississippiensis).

PubMed

Eme, John; Hicks, James W; Crossley, Dane A

2011-10-01

Hypoxia is a naturally occurring environmental challenge for embryonic non-avian reptiles, and this study is the first to investigate the impact of chronic hypoxia on a possible chemoreflex loop in a developing non-avian reptile. We measured heart rate and blood pressure in normoxic and hypoxic-incubated (10% O(2)) American alligator embryos (Alligator mississippiensis) at 70 and 90/95% of development. We hypothesized that hypoxic incubation would blunt embryonic alligators' response to a reflex loop stimulated by phenylbiguanide (PBG), a 5-HT(3) receptor agonist that stimulates vagal pulmonary C-fiber afferents. PBG injection caused a hypotensive bradycardia in 70 and 95% of development embryos (paired t tests, P < 0.05), a response similar to mammals breathing inspired air (all injections made through occlusive catheter in tertiary chorioallantoic membrane artery). Hypoxic incubation blunted the bradycardic response to PBG in embryos at 95% of development (two-way ANOVA, P < 0.01). We also demonstrated that the vagally mediated afferent limb of this reflex can be partially or completely blocked in ovo with a 5-HT(3) receptor blockade using ondansetron hydrochloride dihydrate (OHD), with a ganglionic blockade using hexamethonium, or with a cholinergic blockade using atropine. Atropine eliminated the hypotensive and bradycardic responses to PBG, and OHD and hexamethonium significantly blunted these responses. This cardiovascular reflex mediated by the vagus was affected by hypoxic incubation, suggesting that reptilian sympathetic and parasympathetic reflex loops have the potential for developmental plasticity in response to hypoxia. We suggest that the American alligator, with an extended length of time between each developmental stage relative to avian species, may provide an excellent model to test the cardiorespiratory effects of prolonged exposure to changes in atmospheric gases. This extended period allows for lengthy studies at each stage without the transition to a new stage, and the natural occurrence of hypoxia and hypercapnia in crocodilian nests makes this stress ecologically and evolutionarily relevant.

Characterization of the Kv channels of mouse carotid body chemoreceptor cells and their role in oxygen sensing

PubMed Central

Pérez-García, M Teresa; Colinas, Olaia; Miguel-Velado, Eduardo; Moreno-Domínguez, Alejandro; López-López, José Ramón

2004-01-01

As there are wide interspecies variations in the molecular nature of the O2-sensitive Kv channels in arterial chemoreceptors, we have characterized the expression of these channels and their hypoxic sensitivity in the mouse carotid body (CB). CB chemoreceptor cells were obtained from a transgenic mouse expressing green fluorescent protein (GFP) under the control of tyrosine hydroxylase (TH) promoter. Immunocytochemical identification of TH in CB cell cultures reveals a good match with GFP-positive cells. Furthermore, these cells show an increase in [Ca2+]i in response to low PO2, demonstrating their ability to engender a physiological response. Whole-cell experiments demonstrated slow-inactivating K+ currents with activation threshold around −30 mV and a bi-exponential kinetic of deactivation (τ of 6.24 ± 0.52 and 32.85 ± 4.14 ms). TEA sensitivity of the currents identified also two different components (IC50 of 17.8 ± 2.8 and 940.0 ± 14.7 μm). Current amplitude decreased reversibly in response to hypoxia, which selectively affected the fast deactivating component. Hypoxic inhibition was also abolished in the presence of low (10–50 μm) concentrations of TEA, suggesting that O2 interacts with the component of the current most sensitive to TEA. The kinetic and pharmacological profile of the currents suggested the presence of Kv2 and Kv3 channels as their molecular correlates, and we have identified several members of these two subfamilies by single-cell PCR and immunocytochemistry. This report represents the first functional and molecular characterization of Kv channels in mouse CB chemoreceptor cells, and strongly suggests that O2-sensitive Kv channels in this preparation belong to the Kv3 subfamily. PMID:15034123

Selective reversible inhibition of autophagy in hypoxic breast cancer cells promotes pulmonary metastasis

PubMed Central

Dower, Christopher M.; Bhat, Neema; Wang, Edward W.; Wang, Hong-Gang

2016-01-01

Autophagy influences how cancer cells respond to nutrient deprivation and hypoxic stress, two hallmarks of the tumor microenvironment (TME). In this study, we explored the impact of autophagy on the pathophysiology of breast cancer cells, using a novel hypoxia-dependent, reversible dominant negative strategy to regulate autophagy at the cellular level within the TME. Suppression of autophagy via hypoxia-induced expression of the kinase-dead unc-51 like autophagy activating kinase (ULK1) mutant K46N increased lung metastases in MDA-MB-231 xenograft mouse models. Consistent with this effect, expressing a dominant-negative mutant of ULK1 or ATG4b or a ULK1-targeting shRNA facilitated cell migration in vitro. Functional proteomic and transcriptome analysis revealed that loss of hypoxia-regulated autophagy promotes metastasis via induction of the fibronectin integrin signaling axis. Indeed, loss of ULK1 function increased fibronectin deposition in the hypoxic TME. Together, our results indicated that hypoxia-regulated autophagy suppresses metastasis in breast cancer by preventing tumor fibrosis. These results also suggest cautions in the development of autophagy-based strategies for cancer treatment. PMID:28115361

Thiopental Inhibits Global Protein Synthesis by Repression of Eukaryotic Elongation Factor 2 and Protects from Hypoxic Neuronal Cell Death

PubMed Central

Schwer, Christian I.; Lehane, Cornelius; Guelzow, Timo; Zenker, Simone; Strosing, Karl M.; Spassov, Sashko; Erxleben, Anika; Heimrich, Bernd; Buerkle, Hartmut; Humar, Matjaz

2013-01-01

Ischemic and traumatic brain injury is associated with increased risk for death and disability. The inhibition of penumbral tissue damage has been recognized as a target for therapeutic intervention, because cellular injury evolves progressively upon ATP-depletion and loss of ion homeostasis. In patients, thiopental is used to treat refractory intracranial hypertension by reducing intracranial pressure and cerebral metabolic demands; however, therapeutic benefits of thiopental-treatment are controversially discussed. In the present study we identified fundamental neuroprotective molecular mechanisms mediated by thiopental. Here we show that thiopental inhibits global protein synthesis, which preserves the intracellular energy metabolite content in oxygen-deprived human neuronal SK-N-SH cells or primary mouse cortical neurons and thus ameliorates hypoxic cell damage. Sensitivity to hypoxic damage was restored by pharmacologic repression of eukaryotic elongation factor 2 kinase. Translational inhibition was mediated by calcium influx, activation of the AMP-activated protein kinase, and inhibitory phosphorylation of eukaryotic elongation factor 2. Our results explain the reduction of cerebral metabolic demands during thiopental treatment. Cycloheximide also protected neurons from hypoxic cell death, indicating that translational inhibitors may generally reduce secondary brain injury. In conclusion our study demonstrates that therapeutic inhibition of global protein synthesis protects neurons from hypoxic damage by preserving energy balance in oxygen-deprived cells. Molecular evidence for thiopental-mediated neuroprotection favours a positive clinical evaluation of barbiturate treatment. The chemical structure of thiopental could represent a pharmacologically relevant scaffold for the development of new organ-protective compounds to ameliorate tissue damage when oxygen availability is limited. PMID:24167567

Fitness to fly in patients with lung disease.

PubMed

Nicholson, Trevor T; Sznajder, Jacob I

2014-12-01

Patients with chronic lung disease may have mild hypoxemia at sea level. Some of these cases may go unrecognized, and even among those who are known to be hypoxemic, some do not use supplemental oxygen. During air travel in a hypobaric hypoxic environment, compensatory pulmonary mechanisms may be inadequate in patients with lung disease despite normal sea-level oxygen requirements. In addition, compensatory cardiovascular mechanisms may be less effective in some patients who are unable to increase cardiac output. Air travel also presents an increased risk of venous thromboembolism. Patients with cystic lung disease may also be at increased risk of pneumothorax. Although overall this risk appears to be relatively low, should a pneumothorax occur, it could present a significant challenge to the patient with chronic lung disease, particularly if hypoxemia is already present. As such, a thorough assessment of patients with chronic lung disease and cardiac disease who are contemplating air travel should be performed. The duration of the planned flight, the anticipated levels of activity, comorbid illnesses, and the presence of risk factors for venous thromboembolism are important considerations. Hypobaric hypoxic challenge testing reproduces an environment most similar to that encountered during actual air travel; however, it is not widely available. Assessment for hypoxia is otherwise best performed using a normobaric hypoxic challenge test. Patients in need of supplemental oxygen need to contact the airline and request this accommodation during flight. They should also be advised on arranging portable oxygen concentrators before air travel, and a discussion of the potential risks of travel should take place.

Chronic reduction in cardiac output induces hypoxic signaling in larval zebrafish even at a time when convective oxygen transport is not required.

PubMed

Kopp, Renate; Schwerte, Thorsten; Egg, Margit; Sandbichler, Adolf Michael; Egger, Bernhard; Pelster, Bernd

2010-09-01

In the present study, the zebrafish breakdance mutant (bre) was used to assess the role of blood flow in development because it has been previously shown that bre larvae have a chronically reduced cardiac output as a result of ventricular contraction following only every second atrial contraction in addition to an atrial bradycardia. We confirmed a 50% reduction compared with control fish and further showed that blood flow in the caudal part of the dorsal aorta decreased by 80%. Associated with these reductions in blood flow were indications of developmental retardation in bre mutants, specifically delayed hatching, reduced cell proliferation, and a transiently decreased growth rate. Surprisingly, an increased red blood cell concentration and an earlier appearance of trunk vessels in bre larvae indicated some compensation to convective oxygen transport, although in previous studies it has been shown that zebrafish larvae at this stage obtain oxygen by bulk diffusion. In bre animals immunohistochemical analyses showed a significant increase in hypoxia inducible factor 1 (HIF)-α protein expression, comparable with wild-type larvae that were raised under hypoxic conditions. Accordingly, the expression of some hif downstream genes was affected. Furthermore, Affymetrix microarray analyses revealed a large number of genes that were differently expressed comparing control and bre larvae, and the number even increased with proceeding development. The results showed that a chronic reduction in blood flow generated hypoxic molecular signals despite partial compensation by increased oxygen carrying capacity and transiently slowed the overall development of zebrafish bre larvae.

The role of inflammation in hypoxic pulmonary hypertension: from cellular mechanisms to clinical phenotypes

PubMed Central

Poth, Jens M.; Fini, Mehdi A.; Olschewski, Andrea; El Kasmi, Karim C.; Stenmark, Kurt R.

2014-01-01

Hypoxic pulmonary hypertension (PH) comprises a heterogeneous group of diseases sharing the common feature of chronic hypoxia-induced pulmonary vascular remodeling. The disease is usually characterized by mild to moderate pulmonary vascular remodeling that is largely thought to be reversible compared with the progressive irreversible disease seen in World Health Organization (WHO) group I disease. However, in these patients, the presence of PH significantly worsens morbidity and mortality. In addition, a small subset of patients with hypoxic PH develop “out-of-proportion” severe pulmonary hypertension characterized by pulmonary vascular remodeling that is irreversible and similar to that in WHO group I disease. In all cases of hypoxia-related vascular remodeling and PH, inflammation, particularly persistent inflammation, is thought to play a role. This review focuses on the effects of hypoxia on pulmonary vascular cells and the signaling pathways involved in the initiation and perpetuation of vascular inflammation, especially as they relate to vascular remodeling and transition to chronic irreversible PH. We hypothesize that the combination of hypoxia and local tissue factors/cytokines (“second hit”) antagonizes tissue homeostatic cellular interactions between mesenchymal cells (fibroblasts and/or smooth muscle cells) and macrophages and arrests these cells in an epigenetically locked and permanently activated proremodeling and proinflammatory phenotype. This aberrant cellular cross-talk between mesenchymal cells and macrophages promotes transition to chronic nonresolving inflammation and vascular remodeling, perpetuating PH. A better understanding of these signaling pathways may lead to the development of specific therapeutic targets, as none are currently available for WHO group III disease. PMID:25416383

Co-regulation of Primary Mouse Hepatocyte Viability and Function by Oxygen and Matrix

PubMed Central

Buck, Lorenna D.; Inman, S. Walker; Rusyn, Ivan; Griffith, Linda G.

2014-01-01

Although oxygen and extracellular matrix cues both influence differentiation state and metabolic function of primary rat and human hepatocytes, relatively little is known about how these factors together regulate behaviors of primary mouse hepatocytes in culture. To determine the effects of pericellular oxygen tension on hepatocellular function, we employed 2 methods of altering oxygen concentration in the local cellular microenvironment of cells cultured in the presence or absence of an extracellular matrix (Matrigel) supplement. By systematically altering medium depth and gas phase oxygen tension, we created multiple oxygen regimes (hypoxic, normoxic, and hyperoxic) and measured the local oxygen concentrations in the pericellular environment using custom-designed oxygen microprobes. From these measurements of oxygen concentrations, we derived values of oxygen consumption rates under a spectrum of environmental contexts, thus providing the first reported estimates of these values for primary mouse hepatocytes. Oxygen tension and matrix microenvironment were found to synergistically regulate hepatocellular survival and function as assessed using quantitative image analysis for cells stained with vital dyes, and assessment of secretion of albumin. Hepatocellular viability was affected only at strongly hypoxic conditions. Surprisingly, albumin secretion rates were greatest at a moderately supra-physiological oxygen concentration, and this effect was mitigated at still greater supra-physiological concentrations. Matrigel enhanced the effects of oxygen on retention of function. This study underscores the importance of carefully controlling cell density, medium depth and gas phase oxygen, as the effects of these parameters on local pericellular oxygen tension and subsequent hepatocellular function are profound. PMID:24222008

Evaluation of Stem Cell-Derived Red Blood Cells as a Transfusion Product Using a Novel Animal Model.

PubMed

Shah, Sandeep N; Gelderman, Monique P; Lewis, Emily M A; Farrel, John; Wood, Francine; Strader, Michael Brad; Alayash, Abdu I; Vostal, Jaroslav G

2016-01-01

Reliance on volunteer blood donors can lead to transfusion product shortages, and current liquid storage of red blood cells (RBCs) is associated with biochemical changes over time, known as 'the storage lesion'. Thus, there is a need for alternative sources of transfusable RBCs to supplement conventional blood donations. Extracorporeal production of stem cell-derived RBCs (stemRBCs) is a potential and yet untapped source of fresh, transfusable RBCs. A number of groups have attempted RBC differentiation from CD34+ cells. However, it is still unclear whether these stemRBCs could eventually be effective substitutes for traditional RBCs due to potential differences in oxygen carrying capacity, viability, deformability, and other critical parameters. We have generated ex vivo stemRBCs from primary human cord blood CD34+ cells and compared them to donor-derived RBCs based on a number of in vitro parameters. In vivo, we assessed stemRBC circulation kinetics in an animal model of transfusion and oxygen delivery in a mouse model of exercise performance. Our novel, chronically anemic, SCID mouse model can evaluate the potential of stemRBCs to deliver oxygen to tissues (muscle) under resting and exercise-induced hypoxic conditions. Based on our data, stem cell-derived RBCs have a similar biochemical profile compared to donor-derived RBCs. While certain key differences remain between donor-derived RBCs and stemRBCs, the ability of stemRBCs to deliver oxygen in a living organism provides support for further development as a transfusion product.

Intra-discal injection of autologous, hypoxic cultured bone marrow-derived mesenchymal stem cells in five patients with chronic lower back pain: a long-term safety and feasibility study.

PubMed

Elabd, Christian; Centeno, Christopher J; Schultz, John R; Lutz, Gregory; Ichim, Thomas; Silva, Francisco J

2016-09-01

Chronic low back pain due to disc degeneration represents a major social and economic burden worldwide. The current standard of care is limited to symptomatic relief and no current approved therapy promotes disc regeneration. Bone marrow-derived mesenchymal stem cells (MSCs) are easily accessible and well characterized. These MSCs are multipotent and exhibit great tissue regenerative potential including bone, cartilage, and fibrous tissue regeneration. The use of this cell-based biologic for treating protruding disc herniation and/or intervertebral disc degeneration is a promising therapeutic strategy, due to their known regenerative, immuno-modulatory and anti-inflammatory properties. Five patients diagnosed with degenerative disc disease received an intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells (15.1-51.6 million cells) as part of a previous study. These patients were re-consented to participate in this study in order to assess long-term safety and feasibility of intra-discal injection of autologous, hypoxic cultured, bone marrow-derived mesenchymal stem cells 4-6 years post mesenchymal stem cell infusion. The follow-up study consisted of a physical examination, a low back MRI, and a quality of life questionnaire. Patients' lower back MRI showed absence of neoplasms or abnormalities surrounding the treated region. Based on the physical examination and the quality of life questionnaire, no adverse events were reported due to the procedure or to the stem cell treatment 4-6 years post autologous, hypoxic cultured mesenchymal stem cell infusion. All patients self-reported overall improvement, as well as improvement in strength, post stem cell treatment, and four out of five patients reported improvement in mobility. This early human clinical data suggests the safety and feasibility of the clinical use of hypoxic cultured bone marrow-derived mesenchymal stem cells for the treatment of lower back pain due to degenerative disc disorders and support further studies utilizing hypoxic cultured bone marrow-derived stem cells. The overall improvements reported are encouraging, but a larger double-blind, controlled, randomized clinical study with significant number of patients and implementation of validated endpoint measurements are next steps in order to demonstrate efficacy of this cell-based biologic.

1,2-Bis(methylsulfonyl)-1-(2-chloroethyl)-2-[[1-(4-nitrophenyl)ethoxy]carbonyl]hydrazine: An anticancer agent targeting hypoxic cells

PubMed Central

Seow, Helen A.; Penketh, Philip G.; Shyam, Krishnamurthy; Rockwell, Sara; Sartorelli, Alan C.

2005-01-01

To target malignant cells residing in hypoxic regions of solid tumors, we have designed and synthesized prodrugs generating the cytotoxic alkylating species 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (90CE) after bioreductive activation. We postulate that one of these agents, 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-[[1-(4-nitrophenyl)ethoxy]carbonyl]hydrazine (KS119), requires enzymatic nitro reduction to produce 90CE, whereas another agent, 1,2-bis(methylsulfonyl)-1-(2-chloroethyl)-2-[(4-nitrobenzyloxy)carbonyl]hydrazine (PNBC), can also be activated by nucleophilic attack by thiols such as glutathione (GSH)/GST. We demonstrated that these agents selectively kill hypoxic EMT6 mouse mammary carcinoma and CHO cells. In hypoxia, 50 μM KS119 produced 5 logs of kill of EMT6 cells without discernable cytotoxicity in air; similar effects were observed with CHO cells. PNBC was less efficacious against hypoxic tumor cells and also had some toxicity to aerobic cells, presumably because of GST/thiol activation, making PNBC less interesting as a selective hypoxic-cell cytotoxin. BALB/c mice with established EMT6 solid tumors were used to demonstrate that KS119 could reach and kill hypoxic cells in solid tumors. To gain information on bioreductive enzymes involved in the activation of KS119, cytotoxicity was measured in CHO cell lines overexpressing NADH:cytochrome b5 reductase (NBR), NADPH:cytochrome P450 reductase (NPR), or NAD(P)H: quinone oxidoreductase 1 (NQO1). Increased cytotoxicity occurred in cells overexpressing NBR and NPR, whereas overexpressed NQO1 had no effect. These findings were supported by enzymatic studies using purified NPR and xanthine oxidase to activate KS119. KS119 has significant potential as a hypoxia-selective tumor-cell cytotoxin and is unlikely to cause major toxicity to well oxygenated normal tissues. PMID:15964988

Hypoxic stress, brain vascular system, and β-amyloid: a primary cell culture study.

PubMed

Muche, Abebe; Bürger, Susanne; Arendt, Thomas; Schliebs, Reinhard

2015-01-01

This study stresses the hypothesis whether hypoxic events contribute to formation and deposition of β-amyloid (Aβ) in cerebral blood vessels by affecting the processing of endothelial amyloid precursor protein (APP). Therefore, cerebral endothelial cells (ECs) derived from transgenic Tg2576 mouse brain, were subjected to short periods of hypoxic stress, followed by assessment of formation and secretion of APP cleavage products sAPPα, sAPPβ, and Aβ as well as the expression of endothelial APP. Hypoxic stress of EC leads to enhanced secretion of sAPPβ into the culture medium as compared to normoxic controls, which is accompanied by increased APP expression, induction of vascular endothelial growth factor (VEGF) synthesis, nitric oxide production, and differential changes in endothelial p42/44 (ERK1/2) expression. The hypoxia-mediated up-regulation of p42/44 at a particular time of incubation was accompanied by a corresponding down-regulation of the phosphorylated form of p42/44. To reveal any role of hypoxia-induced VEGF in endothelial APP processing, ECs were exposed by VEGF. VEGF hardly affected the amount of sAPPβ and Aβ(1-40) secreted into the culture medium, whereas the suppression of the VEGF receptor action by SU-5416 resulted in decreased release of sAPPβ and Aβ(1-40) in comparison to control incubations, suggesting a role of VEGF in controlling the activity of γ-secretase, presumably via the VEGF receptor-associated tyrosine kinase. The data suggest that hypoxic stress represents a mayor risk factor in causing Aβ deposition in the brain vascular system by favoring the amyloidogenic route of endothelial APP processing. The hypoxic-stress-induced changes in β-secretase activity are presumably mediated by altering the phosphorylation status of p42/44, whereas the stress-induced up-regulation of VEGF appears to play a counteracting role by maintaining the balance of physiological APP processing.

Impact of Chronic Hypoxia on Proximal Pulmonary Artery Wave Propagation and Mechanical Properties in Rats.

PubMed

Su, Junjing; Logan, Charmilie C; Hughes, Alun D; Parker, Kim H; Dhutia, Niti M; Danielsen, Carl Christian; Simonsen, Ulf

2018-03-16

Arterial stiffness and wave reflection are important components of the ventricular afterload. Therefore, we aimed to assess the arterial wave characteristics and mechanical properties of the proximal pulmonary arteries (PAs) in the hypoxic pulmonary hypertensive rat model. After 21 days in normoxic or hypoxic chambers (24 animals in each group), the animals underwent transthoracic echocardiography and pulmonary artery catheterization with a dual-tipped pressure and Doppler flow sensor wire. Wave intensity analysis (WIA) was performed. Artery rings obtained from the pulmonary trunk, right and left PAs and the aorta were subjected to a tensile test to rupture. Collagen and elastin content was determined. In hypoxic rats, proximal PA wall thickness, collagen content, tensile strength per unit collagen, maximal elastic modulus and wall viscosity increased; while the elastin:collagen ratio and arterial distensibility decreased. Arterial pulse wave velocity was also increased and the increase was more prominent in vivo than ex vivo. Wave intensity was similar in the hypoxic and normoxic animals with negligible wave reflection. In contrast, aortic maximal elastic modulus remained unchanged, while the wall viscosity decreased. There was no evidence of altered arterial wave propagation in the proximal PAs of hypoxic rats, while the extracellular matrix protein composition altered and the collagen tensile strength increased. This was accompanied by altered mechanical properties in vivo and ex vivo.

Implication of the ryanodine receptor in TRPV4-induced calcium response in pulmonary arterial smooth muscle cells from normoxic and chronically hypoxic rats.

PubMed

Dahan, Diana; Ducret, Thomas; Quignard, Jean-François; Marthan, Roger; Savineau, Jean-Pierre; Estève, Eric

2012-11-01

There is a growing body of evidence indicating that transient receptor potential (TRP) channels are implicated in calcium signaling and various cellular functions in the pulmonary vasculature. The aim of this study was to investigate the expression, functional role, and coupling to reticulum calcium channels of the type 4 vanilloid TRP subfamily (TRPV4) in the pulmonary artery from both normoxic (Nx) and chronically hypoxic (CH) rats. Activation of TRPV4 with the specific agonist 4α-phorbol-12,13-didecanoate (4α-PDD, 5 μM) increased the intracellular calcium concentration ([Ca(2+)](i)). This effect was significantly reduced by a high concentration of ryanodine (100 μM) or chronic caffeine (5 mM) that blocked ryanodine receptor (RyR) but was insensitive to xestospongin C (10 μM), an inositol trisphosphate receptor antagonist. Inhibition of RyR1 and RyR3 only with 10 μM of dantrolene did not attenuate the 4α-PDD-induced [Ca(2+)](i) increase. Western blotting experiments revealed the expression of TRPV4 and RyR2 with an increase in both receptors in pulmonary arteries from CH rats vs. Nx rats. Accordingly, the 4α-PDD-activated current, measured with patch-clamp technique, was increased in pulmonary artery smooth muscle cells (PASMC) from CH rats vs. Nx rats. 4α-PDD increased isometric tension in artery rings, and this response was also potentiated under chronic hypoxia conditions. 4α-PDD-induced calcium response, current, and contraction were all inhibited by the selective TRPV4 blocker HC-067047. Collectively, our findings provide evidence of the interplay between TRPV4 and RyR2 in the Ca(2+) release mechanism and contraction in PASMC. This study provides new insights onto the complex calcium signaling in PASMC and point out the importance of the TRPV4-RyR2 signaling pathway under hypoxic conditions that may lead to pulmonary hypertension.

Predicting hypoxaemia during flights in children with cystic fibrosis

PubMed Central

Buchdahl, R; Babiker, A; Bush, A; Cramer, D

2001-01-01

BACKGROUND—We have previously suggested that it is possible to predict oxygen desaturation during flight in children with cystic fibrosis and chronic lung disease by non-invasive measurement of oxygen saturation following inhalation of 15% oxygen—the pre-flight hypoxic challenge. This study reports on the results of measurements over 5years.
METHODS—The study comprised a pre-flight hypoxic challenge measuring oxygen saturation by finger tip pulse oximetry (SpO2) during tidal breathing of 15% oxygen in nitrogen and spirometric testing 1 month before the flight followed by SpO2 measurements during intercontinental flights to and from holidays abroad with children in wake and sleep states.
RESULTS—Pre-flight tests were completed on 87 children with cystic fibrosis. Desaturation of <90% occurred in 10 children at some stage during the flight, three of whom received supplementary oxygen. Using a cut off SpO2 of 90%, the pre-flight hypoxic challenge correctly predicted desaturation in only two of these children. The sensitivity and specificity of the pre-flight hypoxic challenge were 20% and 99%, respectively, compared with 70% and 96% for spirometric tests (using a cut off for forced expiratory volume in 1 second (FEV1) of <50% predicted). Overall, pre-flight spirometric tests were a better predictor of desaturation during flight with the area under the Receiver Operating Characteristic (ROC) curve of 0.89 compared with 0.73 for the hypoxic challenge test.
CONCLUSIONS—In this group of subjects pre-flight spirometric testing was a better predictor of desaturation during flight than the pre-flight hypoxic challenge.

 PMID:11641514

Flight assessment in patients with respiratory disease: hypoxic challenge testing vs. predictive equations.

PubMed

Martin, S E; Bradley, J M; Buick, J B; Bradbury, I; Elborn, J S

2007-06-01

Predictive equations have been proposed as a simpler alternative to hypoxic challenge testing (HCT) for determining the risk of in-flight hypoxia. To assess agreement between hypoxic challenge testing (HCT) and predictive equations for assessment of in-flight hypoxia. Retrospective study. Patients with chronic obstructive pulmonary disease (COPD) (n = 15), interstitial lung disease (ILD) (n = 15) and cystic fibrosis (CF) (n = 15) were studied. Spirometry was recorded prior to hypoxic inhalation and oxygen saturations (SpO2) were recorded before, after and during hypoxic inhalation. Blood gases were analysed before and after hypoxic inhalation and when SpO2 = 85%. An HCT was performed using the Ventimask method. The PaO2 at altitude was estimated for each group using four published predictive equations, which use values of PaO2 (ground) and lung function measurements to predict altitude PaO2. Results were interpreted using the BTS recommendations for prescription of in-flight oxygen post HCT. The Stuart Maxwell test of overall homogeneity was used to assess agreement between HCT results and each of the predictive equations. Ground PaO2 was significantly greater in patients with CF than either ILD or COPD (p < 0.05). PaO2 in all three groups significantly decreased following HCT. With the exception of equation 3, significantly fewer patients in each group would require in-flight O2 if prescription was based on HCT, compared to predictive equations (p < 0.05). Predictive equations considerably overestimate the need for in-flight O2, compared to HCT.

Opiorphin is a master regulator of the hypoxic response in corporal smooth muscle cells

PubMed Central

Fu, Shibo; Tar, Moses Tarndie; Melman, Arnold; Davies, Kelvin Paul

2014-01-01

Men with sickle cell disease (SCD) risk developing priapism. Recognizing that SCD is a disease of hypoxia, we investigated the effect of hypoxia on gene expression in corporal smooth muscle (CSM) cells. Rat CSM cells in vitro were treated with CoCl2 or low oxygen tension to mimic hypoxia. Hypoxic conditions increased expression of genes previously associated with priapism in animal models. Variable coding sequence a1 (Vcsa1; the rat opiorphin homologue, sialorphin), hypoxia-inducible factor 1a (Hif-1a), and A2B adenosine receptor (a2br) were increased by 10-, 4-, and 6-fold, respectively, by treatment with CoCl2, whereas low oxygen tension caused increases in expression of 3-, 4-, and 1.5-fold, respectively. Sialorphin-treated CSM cells increased expression of Hif-1a and a2br by 4-fold, and vcsa1-siRNA treatment reduced expression by ∼50%. Using a Hif-1a inhibitor, we demonstrated up-regulation of a2br by sialorphin is dependent on Hif-1a, and knockdown of vcsa1 expression with vcsa1-siRNA demonstrated that hypoxic-up-regulation of Hif-1a is dependent on vcsa1. In CSM from a SCD mouse, there was 15-fold up-regulation of opiorphin at a life stage prior to priapism. We conclude that in CSM, opiorphins are master regulators of the hypoxic response. Opiorphin up-regulation in response to SCD-associated hypoxia activates CSM “relaxant” pathways; excessive activation of these pathways results in priapism.—Fu, S., Tar, M. T., Melman, A., Davies, K. P. Opiorphin is a master regulator of the hypoxic response in corporal smooth muscle cells. PMID:24803544

Hypoxic stress induces, but cannot sustain trophoblast stem cell differentiation to labyrinthine placenta due to mitochondrial insufficiency

PubMed Central

Xie, Yufen; Zhou, Sichang; Jiang, Zhongliang; Dai, Jing; Puscheck, Elizabeth E; Lee, Icksoo; Parker, Graham; Hüttemann, Maik; Rappolee, Daniel A

2014-01-01

Dysfunctional stem cell differentiation into placental lineages is associated with gestational diseases. Of the differentiated lineages available to trophoblast stem cells (TSC), elevated O2 and mitochondrial function are necessary to placental lineages at the maternal-placental surface and important in the etiology of preeclampsia. TSC lineage imbalance leads to embryonic failure during uterine implantation. Stress at implantation exacerbates stem cell depletion by decreasing proliferation and increasing differentiation. Implantation site O2 is normally ~2%. In culture, exposure to 2% O2 and fibroblast growth factor (FGF)4 enabled highest mouse TSC multipotency and proliferation. In contrast, hypoxic stress (0.5% O2) initiated the most TSC differentiation after 24 hr despite FGF4. However, hypoxic stress supported differentiation poorly after 4–7 days, despite FGF4 removal. At all tested O2 levels, FGF4 maintained Warburg metabolism; mitochondrial inactivity and aerobic glycolysis. However, hypoxic stress suppressed mitochondrial membrane potential, maintained low mitochondrial cytochrome c oxidase (oxidative phosphorylation/OxPhos), and high pyruvate kinase M2 (glycolysis) despite FGF4 removal. Inhibiting OxPhos inhibited differentiation at the differentiation optimum at 20% O2. Moreover, adding differentiation-inducing hyperosmolar stress failed to induce differentiation during hypoxia. Thus, differentiation depended on OxPhos at 20% O2; hypoxic and hyperosmolar stresses did not induce differentiation at 0.5% O2. Hypoxia-limited differentiation and mitochondrial inhibition and activation suggest that differentiation into two lineages of the labyrinthine placenta requires O2>0.5–2% and mitochondrial function. Stress-activated protein kinase increases an early lineage and suppresses later lineages in proportion to the deviation from optimal O2 for multipotency, thus it is the first enzyme reported to prioritize differentiation. PMID:25239494

Rapamycin (sirolimus) protects against hypoxic damage in primary heart cultures via Na+/Ca2+ exchanger activation.

PubMed

El-Ani, Dalia; Stav, Hagit; Guetta, Victor; Arad, Michael; Shainberg, Asher

2011-07-04

Rapamycin (sirolimus) is an antibiotic that inhibits protein synthesis through mammalian targeting of rapamycin (mTOR) signaling, and is used as an immunosuppressant in the treatment of organ rejection in transplant recipients. Rapamycin confers preconditioning-like protection against ischemic-reperfusion injury in isolated mouse heart cultures. Our aim was to further define the role of rapamycin in intracellular Ca(2+) homeostasis and to investigate the mechanism by which rapamycin protects cardiomyocytes from hypoxic damage. We demonstrate here that rapamycin protects rat heart cultures from hypoxic-reoxygenation (H/R) damage, as revealed by assays of lactate dehydrogenase (LDH) and creatine kinase (CK) leakage to the medium, by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) measurements, and desmin immunostaining. As a result of hypoxia, intracellular calcium levels ([Ca(2+)](i)) were elevated. However, treatment of heart cultures with rapamycin during hypoxia attenuated the increase of [Ca(2+)](i). Rapamycin also attenuated (45)Ca(2+) uptake into the sarcoplasmic reticulum (SR) of skinned heart cultures in a dose- and time-dependent manner. KB-R7943, which inhibits the "reverse" mode of Na(+)/Ca(2+) exchanger (NCX), protected heart cultures from H/R damage with or without the addition of rapamycin. Rapamycin decreased [Ca(2+)](i) following its elevation by extracellular Ca(2+) ([Ca(2+)](o)) influx, thapsigargin treatment, or depolarization with KCl. We suggest that rapamycin induces cardioprotection against hypoxic/reoxygenation damage in primary heart cultures by stimulating NCX to extrude Ca(2+) outside the cardiomyocytes. According to our findings, rapamycin preserves Ca(2+) homeostasis and prevents Ca(2+) overload via extrusion of Ca(2+) surplus outside the sarcolemma, thereby protecting the cells from hypoxic stress. Copyright © 2011 Elsevier Inc. All rights reserved.

Long-term effects of prenatal hypoxia on endothelium-dependent relaxation responses in pulmonary arteries of adult sheep.

PubMed

Liu, Jie; Gao, Yuansheng; Negash, Sewite; Longo, Lawrence D; Raj, J Usha

2009-03-01

Chronic hypoxia during the course of pregnancy is a common insult to the fetus. However, its long-term effect on the pulmonary vasculature in adulthood has not been described. In this study, the vasorelaxation responses of conduit pulmonary arteries in adult female sheep that were chronically hypoxic as fetuses and raised postnatally at sea level were investigated. Vessel tension studies revealed that endothelium-dependent relaxation responses were attenuated in pulmonary arteries from adult sheep that experienced prenatal hypoxia. Endothelial nitric oxide synthase (eNOS) protein expression was unchanged, but eNOS activity was significantly decreased in pulmonary arteries from prenatally hypoxic sheep. Protein expression of eNOS partners, caveolin-1, calmodulin, and heat shock protein 90 (Hsp90) did not change following prenatal hypoxia. However, the association between eNOS and caveolin-1, its inhibitory binding partner, was significantly increased, whereas association between eNOS and its stimulatory partners calmodulin and Hsp90 was greatly decreased. Furthermore, phosphorylation of Ser(1177) in eNOS decreased, whereas phosphorylation of Thr(495) increased, in the prenatally hypoxic pulmonary arteries, events that are related to eNOS activity. These data demonstrate that prenatal hypoxia results in persistent abnormalities in endothelium-dependent relaxation responses of pulmonary arteries in adult sheep due to decreased eNOS activity resulting from altered posttranslational regulation.

Long-term effects of prenatal hypoxia on endothelium-dependent relaxation responses in pulmonary arteries of adult sheep

PubMed Central

Liu, Jie; Gao, Yuansheng; Negash, Sewite; Longo, Lawrence D.; Raj, J. Usha

2009-01-01

Chronic hypoxia during the course of pregnancy is a common insult to the fetus. However, its long-term effect on the pulmonary vasculature in adulthood has not been described. In this study, the vasorelaxation responses of conduit pulmonary arteries in adult female sheep that were chronically hypoxic as fetuses and raised postnatally at sea level were investigated. Vessel tension studies revealed that endothelium-dependent relaxation responses were attenuated in pulmonary arteries from adult sheep that experienced prenatal hypoxia. Endothelial nitric oxide synthase (eNOS) protein expression was unchanged, but eNOS activity was significantly decreased in pulmonary arteries from prenatally hypoxic sheep. Protein expression of eNOS partners, caveolin-1, calmodulin, and heat shock protein 90 (Hsp90) did not change following prenatal hypoxia. However, the association between eNOS and caveolin-1, its inhibitory binding partner, was significantly increased, whereas association between eNOS and its stimulatory partners calmodulin and Hsp90 was greatly decreased. Furthermore, phosphorylation of Ser1177 in eNOS decreased, whereas phosphorylation of Thr495 increased, in the prenatally hypoxic pulmonary arteries, events that are related to eNOS activity. These data demonstrate that prenatal hypoxia results in persistent abnormalities in endothelium-dependent relaxation responses of pulmonary arteries in adult sheep due to decreased eNOS activity resulting from altered posttranslational regulation. PMID:19136582

Co-regulation of primary mouse hepatocyte viability and function by oxygen and matrix.

PubMed

Buck, Lorenna D; Inman, S Walker; Rusyn, Ivan; Griffith, Linda G

2014-05-01

Although oxygen and extracellular matrix cues both influence differentiation state and metabolic function of primary rat and human hepatocytes, relatively little is known about how these factors together regulate behaviors of primary mouse hepatocytes in culture. To determine the effects of pericellular oxygen tension on hepatocellular function, we employed two methods of altering oxygen concentration in the local cellular microenvironment of cells cultured in the presence or absence of an extracellular matrix (Matrigel) supplement. By systematically altering medium depth and gas phase oxygen tension, we created multiple oxygen regimes (hypoxic, normoxic, and hyperoxic) and measured the local oxygen concentrations in the pericellular environment using custom-designed oxygen microprobes. From these measurements of oxygen concentrations, we derived values of oxygen consumption rates under a spectrum of environmental contexts, thus providing the first reported estimates of these values for primary mouse hepatocytes. Oxygen tension and matrix microenvironment were found to synergistically regulate hepatocellular survival and function as assessed using quantitative image analysis for cells stained with vital dyes, and assessment of secretion of albumin. Hepatocellular viability was affected only at strongly hypoxic conditions. Surprisingly, albumin secretion rates were greatest at a moderately supra-physiological oxygen concentration, and this effect was mitigated at still greater supra-physiological concentrations. Matrigel enhanced the effects of oxygen on retention of function. This study underscores the importance of carefully controlling cell density, medium depth, and gas phase oxygen, as the effects of these parameters on local pericellular oxygen tension and subsequent hepatocellular function are profound. © 2014 Wiley Periodicals, Inc.

Protective Effect of N-acetylcysteine on Liver Damage During Chronic Intrauterine Hypoxia in Fetal Guinea Pig

PubMed Central

Hashimoto, Kazumasa; Pinkas, Gerard; Evans, LaShauna; Liu, Hongshan; Al-Hasan, Yazan

2012-01-01

Chronic exposure to hypoxia during pregnancy generates a stressed intrauterine environment that may lead to fetal organ damage. The objectives of the study are (1) to quantify the effect of chronic hypoxia in the generation of oxidative stress in fetal guinea pig liver and (2) to test the protective effect of antioxidant treatment in hypoxic fetal liver injury. Pregnant guinea pigs were exposed to either normoxia (NMX) or 10.5% O2 (HPX, 14 days) prior to term (65 days) and orally administered N-acetylcysteine ([NAC] 10 days). Near-term anesthetized fetuses were excised and livers examined by histology and assayed for malondialdehyde (MDA) and DNA fragmentation. Chronic HPX increased erythroid precursors, MDA (NMX vs HPX; 1.26 ± 0.07 vs 1.78 ± 0.07 nmol/mg protein; P < .001, mean ± standard error of the mean [SEM]) and DNA fragmentation levels in fetal livers (0.069 ± 0.01 vs 0.11 ± 0.005 OD/mg protein; P < .01). N-acetylcysteine inhibited erythroid aggregation and reduced (P < .05) both MDA and DNA fragmentation of fetal HPX livers. Thus, chronic intrauterine hypoxia generates cell and nuclear damage in the fetal guinea pig liver. Maternal NAC inhibited the adverse effects of fetal liver damage suggestive of oxidative stress. The suppressive effect of maternal NAC may implicate the protective role of antioxidants in the prevention of liver injury in the hypoxic fetus. PMID:22534333

Quantification of oxygen-induced retinopathy in the mouse: a model of vessel loss, vessel regrowth and pathological angiogenesis

PubMed Central

Connor, Kip M; Krah, Nathan M; Dennison, Roberta J; Aderman, Christopher M; Chen, Jing; Guerin, Karen I; Sapieha, Przemyslaw; Stahl, Andreas; Willett, Keirnan L; Smith, Lois E H

2013-01-01

The mouse model of oxygen-induced retinopathy (OIR) has been widely used in studies related to retinopathy of prematurity, proliferative diabetic retinopathy and in studies evaluating the efficacy of antiangiogenic compounds. In this model, 7-d-old (P7) mouse pups with nursing mothers are subjected to hyperoxia (75% oxygen) for 5 d, which inhibits retinal vessel growth and causes significant vessel loss. on P12, mice are returned to room air and the hypoxic avascular retina triggers both normal vessel regrowth and retinal neovascularization (NV), which is maximal at P17. neovascularization spontaneously regresses between P17 and P25. although the OIR model has been the cornerstone of studies investigating proliferative retinopathies, there is currently no harmonized protocol to assess aspects of angiogenesis and treatment outcome. In this protocol we describe standards for mouse size, sample size, retinal preparation, quantification of vascular loss, vascular regrowth, NV and neovascular regression. PMID:19816419

Targeting tumor hypoxia: suppression of breast tumor growth and metastasis by novel carbonic anhydrase IX inhibitors.

PubMed

Lou, Yuanmei; McDonald, Paul C; Oloumi, Arusha; Chia, Stephen; Ostlund, Christina; Ahmadi, Ardalan; Kyle, Alastair; Auf dem Keller, Ulrich; Leung, Samuel; Huntsman, David; Clarke, Blaise; Sutherland, Brent W; Waterhouse, Dawn; Bally, Marcel; Roskelley, Calvin; Overall, Christopher M; Minchinton, Andrew; Pacchiano, Fabio; Carta, Fabrizio; Scozzafava, Andrea; Touisni, Nadia; Winum, Jean-Yves; Supuran, Claudiu T; Dedhar, Shoukat

2011-05-01

Carbonic anhydrase IX (CAIX) is a hypoxia and HIF-1-inducible protein that regulates intra- and extracellular pH under hypoxic conditions and promotes tumor cell survival and invasion in hypoxic microenvironments. Interrogation of 3,630 human breast cancers provided definitive evidence of CAIX as an independent poor prognostic biomarker for distant metastases and survival. shRNA-mediated depletion of CAIX expression in 4T1 mouse metastatic breast cancer cells capable of inducing CAIX in hypoxia resulted in regression of orthotopic mammary tumors and inhibition of spontaneous lung metastasis formation. Stable depletion of CAIX in MDA-MB-231 human breast cancer xenografts also resulted in attenuation of primary tumor growth. CAIX depletion in the 4T1 cells led to caspase-independent cell death and reversal of extracellular acidosis under hypoxic conditions in vitro. Treatment of mice harboring CAIX-positive 4T1 mammary tumors with novel CAIX-specific small molecule inhibitors that mimicked the effects of CAIX depletion in vitro resulted in significant inhibition of tumor growth and metastasis formation in both spontaneous and experimental models of metastasis, without inhibitory effects on CAIX-negative tumors. Similar inhibitory effects on primary tumor growth were observed in mice harboring orthotopic tumors comprised of lung metatstatic MDA-MB-231 LM2-4(Luc+) cells. Our findings show that CAIX is vital for growth and metastasis of hypoxic breast tumors and is a specific, targetable biomarker for breast cancer metastasis.

Hematology from embryo to adult in the bobwhite quail (Colinus virginianus): Differential effects in the adult of clutch, sex and hypoxic incubation.

PubMed

Flores-Santin, Josele; Rojas Antich, Maria; Tazawa, Hiroshi; Burggren, Warren W

2018-04-01

Hematology and its regulation in developing birds have been primarily investigated in response to relatively short-term environmental challenges in the embryo. Yet, whether any changes induced in the embryo persist into adulthood as a hematological form of "fetal programming" is unknown. We hypothesized that: 1) chronic as opposed to acute hypoxic incubation will alter hematological respiratory variables in embryos of bobwhite quail (Colinus virginianus), and 2) alterations first appearing in the embryo will persist into hatchlings through into adulthood. To test these hypotheses, we first developed an embryo-to-adult profile of normal hematological development by measuring hematocrit (Hct), red blood cell concentration ([RBC]), hemoglobin concentration ([Hb]), mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, as well plasma osmolality. Hct, [RBC] and [Hb] in normoxic-incubated birds (controls) steadily increased from ~22%, ~1.6 × 10 6  μL -1 and ~7 g% in day 12 embryos to almost double the values at maturity in adult birds. Both cohort and sex affected hematology of normoxic-incubated birds. A second population, incubated from day 0 (d0) in 15% O 2 , surprisingly revealed little or no significant difference from controls in hematology in embryos. In hatchlings and adults, hypoxic incubation caused no significant modification to any variables. Compared to major hematological effects caused by hypoxic incubation in chickens, the hematology of the bobwhite quail embryo appears to be minimally affected by hypoxic incubation, with very few effects induced during hypoxic incubation actually persisting into adulthood. Copyright © 2018 Elsevier Inc. All rights reserved.

Improving sneaky-sex in a low oxygen environment: reproductive and physiological responses of male mosquito fish to chronic hypoxia.

PubMed

Carter, Alecia J; Wilson, Robbie S

2006-12-01

Few studies have examined the adaptive significance of reversible acclimation responses. The aerobic performance and mating behaviour of the sexually coercive male eastern mosquito fish (Gambusia holbrooki) offers an excellent model system for testing the benefits of reversible acclimation responses to mating success. We exposed male mosquito fish to normoxic or hypoxic conditions for 4 weeks and tested their maximum sustained swimming performance and their ability to obtain coercive matings under both normoxic and hypoxic conditions. We predicted that hypoxia-acclimated males would possess greater swimming and mating performance in hypoxic conditions than normoxic-acclimated males, and vice versa when tested in normoxia. Supporting our predictions, we found the sustained swimming performance of male mosquito fish was greater in a hypoxic environment following long-term exposure to low partial pressures of oxygen. However, the benefits of acclimation responses to mating performance were dependent on whether they were tested in the presence or absence of male-male competition. In a non-competitive environment, male mosquito fish acclimated to hypoxic conditions spent a greater amount of time following females and obtained more copulations than normoxic-acclimated males when tested in low partial pressures of oxygen. When males were competed against each other for copulations, we found no influence of long-term exposure to different partial pressures of oxygen on mating behaviour. Thus, despite improvements in the aerobic capacity of male mosquito fish following long-term acclimation to hypoxic conditions, these benefits did not always manifest themselves in improved mating performance. This study represents one of the first experimental tests of the benefits of reversible acclimation responses, and indicates that the ecological significance of physiological plasticity may be more complicated than previously imagined.

Dietary nitrate increases arginine availability and protects mitochondrial complex I and energetics in the hypoxic rat heart

PubMed Central

Ashmore, Tom; Fernandez, Bernadette O; Branco-Price, Cristina; West, James A; Cowburn, Andrew S; Heather, Lisa C; Griffin, Julian L; Johnson, Randall S; Feelisch, Martin; Murray, Andrew J

2014-01-01

Hypoxic exposure is associated with impaired cardiac energetics in humans and altered mitochondrial function, with suppressed complex I-supported respiration, in rat heart. This response might limit reactive oxygen species generation, but at the cost of impaired electron transport chain (ETC) activity. Dietary nitrate supplementation improves mitochondrial efficiency and can promote tissue oxygenation by enhancing blood flow. We therefore hypothesised that ETC dysfunction, impaired energetics and oxidative damage in the hearts of rats exposed to chronic hypoxia could be alleviated by sustained administration of a moderate dose of dietary nitrate. Male Wistar rats (n = 40) were given water supplemented with 0.7 mmol l−1 NaCl (as control) or 0.7 mmol l−1 NaNO3, elevating plasma nitrate levels by 80%, and were exposed to 13% O2 (hypoxia) or normoxia (n = 10 per group) for 14 days. Respiration rates, ETC protein levels, mitochondrial density, ATP content and protein carbonylation were measured in cardiac muscle. Complex I respiration rates and protein levels were 33% lower in hypoxic/NaCl rats compared with normoxic/NaCl controls. Protein carbonylation was 65% higher in hearts of hypoxic rats compared with controls, indicating increased oxidative stress, whilst ATP levels were 62% lower. Respiration rates, complex I protein and activity, protein carbonylation and ATP levels were all fully protected in the hearts of nitrate-supplemented hypoxic rats. Both in normoxia and hypoxia, dietary nitrate suppressed cardiac arginase expression and activity and markedly elevated cardiac l-arginine concentrations, unmasking a novel mechanism of action by which nitrate enhances tissue NO bioavailability. Dietary nitrate therefore alleviates metabolic abnormalities in the hypoxic heart, improving myocardial energetics. PMID:25172947

Effect of fetal hypoxia on heart susceptibility to ischemia and reperfusion injury in the adult rat.

PubMed

Li, Guohu; Xiao, Yuhui; Estrella, Jaymie L; Ducsay, Charles A; Gilbert, Raymond D; Zhang, Lubo

2003-07-01

Epidemiologic studies showed an association between adverse intrauterine environment and ischemic heart disease in the adult. We tested the hypothesis that prenatal hypoxia increased the susceptibility of adult heart to ischemia-reperfusion (I-R) injury. Time-dated pregnant rats were divided between normoxic and hypoxic (10.5% oxygen from day 15 to 21) groups. Hearts of 6-month-old male progeny were studied using Langendorff preparation and were subjected to two protocols of I-R: 10 minutes of ischemia and 3 hours of reperfusion (I-R(10)) or 25 minutes of ischemia and 3 hours of reperfusion (I-R(25)). Prenatal hypoxia did not change basal left ventricular (LV) function. I-R(10) produced myocardial stunning and a transient decrease in LV function in control hearts but caused myocardial infarction and a persistent decrease in postischemic recovery of LV function in hypoxic hearts. I-R(25) caused myocardial infarction in both control and hypoxic hearts, which was significantly higher in hypoxic hearts. The postischemic recovery of LV function was significantly reduced in hypoxic hearts. I-R(25)-induced activation of caspase-3 and apoptosis in the left ventricle were significantly higher in hypoxic than control hearts. There was a significant decrease in LV heat shock protein 70 and endothelial nitric oxide synthase levels in hypoxic hearts. Prenatal hypoxia did not change beta(1)-adrenoreceptor levels but significantly increased beta(2)-adrenoreceptor in the left ventricle. In addition, it increased G(s)alpha but decreased G(i)alpha. Prenatal chronic hypoxia increases the susceptibility of adult heart to I-R injury. Several possible mechanisms may be involved, including an increase in beta(2)-adrenoreceptor and the G(s)alpha/G(i)alpha ratio, and a decrease in heat shock protein 70 and endothelial nitric oxide synthase in the left ventricle.

[Chronic hypoxia and cardiovascular risk : Clinical significance of different forms of hypoxia].

PubMed

Koehler, U; Hildebrandt, O; Krönig, J; Grimm, W; Otto, J; Hildebrandt, W; Kinscherf, R

2018-06-01

It is of fundamental importance to differentiate whether chronic hypoxia occurs intermittently or persistently. While chronic intermittent hypoxia (CIH) is found typically in patients with obstructive sleep apnea (OAS), chronic persistent hypoxia (CPH) is typically diagnosed in patients with chronic lung disease. Cardiovascular risk is markedly increased in patients with CIH compared to patients with CPH. The frequent change between oxygen desaturation and reoxygenation in patients with CIH is associated with increased hypoxic stress, increased systemic inflammation, and enhanced adrenergic activation followed by endothelial dysfunction and increased arteriosclerosis. The pathophysiologic consequences of CPH are less well understood. The relationship between CPH and the development of pulmonary hypertension, pulmonary heart disease as well as polycythemia has been established.

Changes in Myocardial Mass Associated with Age and Stress: Reexamination of Ventricular Hypertrophy.

ERIC Educational Resources Information Center

George, Colleen; And Others

1985-01-01

One hundred twenty-six rats were studied to determine the effects of exercise, high altitude, and age upon right and left ventricular mass. Chronically hypoxic rats had significantly larger right ventricles but significantly smaller left ventricles than exercised or control rats. (Author/MT)

Cerebral Dysfunctions Related to Perinatal Organic Damage: Clinical-Neuropathologic Correlations.

ERIC Educational Resources Information Center

Towbin, Abraham

1978-01-01

Recent neuropathology studies identify hypoxia as the main cause of perinatal cerebral damage. Cerebral lesions present at birth, with transition to chronic scar lesions, are correlated to mental retardation, cerebral palsy, epilepsy, and minimal brain dysfunction. Gestation age and severity of hypoxic exposure essentially determine the cerebral…

Antileukemic activity of sulforaphane in primary blasts from patients affected by myelo- and lympho-proliferative disorders and in hypoxic conditions.

PubMed

Fimognari, Carmela; Turrini, Eleonora; Sestili, Piero; Calcabrini, Cinzia; Carulli, Giovanni; Fontanelli, Giulia; Rousseau, Martina; Cantelli-Forti, Giorgio; Hrelia, Patrizia

2014-01-01

Sulforaphane is a dietary isothiocyanate found in cruciferous vegetables showing antileukemic activity. With the purpose of extending the potential clinical impact of sulforaphane in the oncological field, we investigated the antileukemic effect of sulforaphane on blasts from patients affected by different types of leukemia and, taking into account the intrinsically hypoxic nature of bone marrow, on a leukemia cell line (REH) maintained in hypoxic conditions. In particular, we tested sulforaphane on patients with chronic lymphocytic leukemia, acute myeloid leukemia, T-cell acute lymphoblastic leukemia, B-cell acute lymphoblastic leukemia, and blastic NK cell leukemia. Sulforaphane caused a dose-dependent induction of apoptosis in blasts from patients diagnosed with acute lymphoblastic or myeloid leukemia. Moreover, it was able to cause apoptosis and to inhibit proliferation in hypoxic conditions on REH cells. As to its cytotoxic mechanism, we found that sulforaphane creates an oxidative cellular environment that induces DNA damage and Bax and p53 gene activation, which in turn helps trigger apoptosis. On the whole, our results raise hopes that sulforaphane might set the stage for a novel therapeutic principle complementing our growing armature against malignancies and advocate the exploration of sulforaphane in a broader population of leukemic patients.

Hypoxic Response of Tumor Tissues in a Microfluidic Environment

NASA Astrophysics Data System (ADS)

Morshed, Adnan; Dutta, Prashanta

2017-11-01

Inside a tumor tissue, cells growing further away from the blood vessel often suffer from low oxygen levels known as hypoxia. Cancer cells have shown prolonged survival in hostile hypoxic conditions by sharply changing the cellular metabolism. In this work, different stages of growth of the tumor tissue and the oxygen transport across the tissue are investigated. The tissue was modeled as a contiguous block of cells inside a microfluidic environment with nutrient transport through advection and diffusion. While oxygen uptake inside the tissue is through diffusion, ascorbate transport from the extracellular medium is addressed by a concentration dependent uptake model. By varying the experimentally observed oxygen consumption rate, different types of cancer cells and their normoxic and hypoxic stages were studied. Even when the oxygen supply in the channel is maintained at normoxic levels, our results show the onset of hypoxia within minutes inside the cellblock. Interestingly, modeled cell blocks with and without a structured basal layer showed less than 5% variation in hypoxic response in chronic hypoxia. Results also indicate that the balance of cell survival and growth are affected by the flow rate of nutrients and the oxygen consumption rate. This work was supported in part by the National Science Foundation under Grant No. DMS 1317671.

Distinct Activities of Glycolytic Enzymes Identify Chronic Lymphocytic Leukemia Patients with a more Aggressive Course and Resistance to Chemo-Immunotherapy.

PubMed

Gdynia, Georg; Robak, Tadeusz; Kopitz, Jürgen; Heller, Anette; Grekova, Svetlana; Duglova, Katarina; Laukemper, Gloria; Heinzel-Gutenbrunner, Monika; Gutenbrunner, Cornelius; Roth, Wilfried; Ho, Anthony D; Schirmacher, Peter; Schmitt, Michael; Dreger, Peter; Sellner, Leopold

2018-06-05

A higher capacity to grow under hypoxic conditions can lead to a more aggressive behavior of tumor cells. Determining tumor activity under hypoxia may identify chronic lymphocytic leukemia (CLL) with aggressive clinical course and predict response to chemo-immunotherapy (CIT). A metabolic score was generated by determining pyruvate kinase and lactate dehydrogenase, key enzymes of glycolysis, ex vivo in primary CLL samples under normoxic and hypoxic conditions. This score was further correlated with clinical endpoints and response to CIT in 96 CLL patients. 45 patients were classified as metabolic high risk (HR), 51 as low risk (LR). Treatment-free survival (TFS) was significantly shorter in HR patients (median 394 vs 723 days, p = .021). 15 HR patients and 14 LR patients received CIT after sample acquisition. HR patients had a significantly shorter progression-free survival after treatment compared to LR patients (median 216 days vs not reached, p = .008). Multivariate analysis evaluating age, IGHV, TP53 deletion or mutation and 11q22-23 deletion besides the capacity of tumor cells to grow under severe hypoxic conditions identified the metabolic profile as the strongest independent risk factor for shorter TFS (hazard ratio 2.37, p = .011). The metabolic risk can provide prognostic and predictive information complementary to genetic biomarkers and identify patients who might benefit from alternative treatment approaches. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Cellular dysfunction in the diabetic fibroblast: impairment in migration, vascular endothelial growth factor production, and response to hypoxia.

PubMed

Lerman, Oren Z; Galiano, Robert D; Armour, Mary; Levine, Jamie P; Gurtner, Geoffrey C

2003-01-01

Although it is known that systemic diseases such as diabetes result in impaired wound healing, the mechanism for this impairment is not understood. Because fibroblasts are essential for wound repair, we compared the in vitro behavior of fibroblasts cultured from diabetic, leptin receptor-deficient (db/db) mice with wild-type fibroblasts from mice of the same genetic background in processes important during tissue repair. Adult diabetic mouse fibroblast migration exhibited a 75% reduction in migration compared to normal fibroblasts (P < 0.001) and was not significantly stimulated by hypoxia (1% O(2)), whereas wild-type fibroblast migration was up-regulated nearly twofold in hypoxic conditions (P < 0.05). Diabetic fibroblasts produced twice the amount of pro-matrix metalloproteinase-9 as normal fibroblasts, as measured by both gelatin zymography and enzyme-linked immunosorbent assay (P < 0.05). Adult diabetic fibroblasts exhibited a sevenfold impairment in vascular endothelial growth factor (VEGF) production (4.5 +/- 1.3 pg/ml versus 34.8 +/- 3.3 pg/ml, P < 0.001) compared to wild-type fibroblasts. Moreover, wild-type fibroblast production of VEGF increased threefold in response to hypoxia, whereas diabetic fibroblast production of VEGF was not up-regulated in hypoxic conditions (P < 0.001). To address the question whether these differences resulted from chronic hyperglycemia or absence of the leptin receptor, fibroblasts were harvested from newborn db/db mice before the onset of diabetes (4 to 5 weeks old). These fibroblasts showed no impairments in VEGF production under basal or hypoxic conditions, confirming that the results from db/db fibroblasts in mature mice resulted from the diabetic state and were not because of alterations in the leptin-leptin receptor axis. Markers of cellular viability including proliferation and senescence were not significantly different between diabetic and wild-type fibroblasts. We conclude that, in vitro, diabetic fibroblasts show selective impairments in discrete cellular processes critical for tissue repair including cellular migration, VEGF production, and the response to hypoxia. The VEGF abnormalities developed concurrently with the onset of hyperglycemia and were not seen in normoglycemic, leptin receptor-deficient db/db mice. These observations support a role for fibroblast dysfunction in the impaired wound healing observed in human diabetics, and also suggest a mechanism for the poor clinical outcomes that occur after ischemic injury in diabetic patients.

Cellular Dysfunction in the Diabetic Fibroblast

PubMed Central

Lerman, Oren Z.; Galiano, Robert D.; Armour, Mary; Levine, Jamie P.; Gurtner, Geoffrey C.

2003-01-01

Although it is known that systemic diseases such as diabetes result in impaired wound healing, the mechanism for this impairment is not understood. Because fibroblasts are essential for wound repair, we compared the in vitro behavior of fibroblasts cultured from diabetic, leptin receptor-deficient (db/db) mice with wild-type fibroblasts from mice of the same genetic background in processes important during tissue repair. Adult diabetic mouse fibroblast migration exhibited a 75% reduction in migration compared to normal fibroblasts (P < 0.001) and was not significantly stimulated by hypoxia (1% O2), whereas wild-type fibroblast migration was up-regulated nearly twofold in hypoxic conditions (P < 0.05). Diabetic fibroblasts produced twice the amount of pro-matrix metalloproteinase-9 as normal fibroblasts, as measured by both gelatin zymography and enzyme-linked immunosorbent assay (P < 0.05). Adult diabetic fibroblasts exhibited a sevenfold impairment in vascular endothelial growth factor (VEGF) production (4.5 ± 1.3 pg/ml versus 34.8 ± 3.3 pg/ml, P < 0.001) compared to wild-type fibroblasts. Moreover, wild-type fibroblast production of VEGF increased threefold in response to hypoxia, whereas diabetic fibroblast production of VEGF was not up-regulated in hypoxic conditions (P < 0.001). To address the question whether these differences resulted from chronic hyperglycemia or absence of the leptin receptor, fibroblasts were harvested from newborn db/db mice before the onset of diabetes (4 to 5 weeks old). These fibroblasts showed no impairments in VEGF production under basal or hypoxic conditions, confirming that the results from db/db fibroblasts in mature mice resulted from the diabetic state and were not because of alterations in the leptin-leptin receptor axis. Markers of cellular viability including proliferation and senescence were not significantly different between diabetic and wild-type fibroblasts. We conclude that, in vitro, diabetic fibroblasts show selective impairments in discrete cellular processes critical for tissue repair including cellular migration, VEGF production, and the response to hypoxia. The VEGF abnormalities developed concurrently with the onset of hyperglycemia and were not seen in normoglycemic, leptin receptor-deficient db/db mice. These observations support a role for fibroblast dysfunction in the impaired wound healing observed in human diabetics, and also suggest a mechanism for the poor clinical outcomes that occur after ischemic injury in diabetic patients. PMID:12507913

miR-26b-5p regulates hypoxia-induced phenotypic switching of vascular smooth muscle cells via the TGF-β/Smad4 signaling pathway.

PubMed

Ruan, Changwu; Lu, Jide; Wang, Hairong; Ge, Zhiru; Zhang, Chenjun; Xu, Maochun

2017-06-01

Hypoxia contributes to the phenotypic switch of vascular smooth muscle cells (VSMCs). Various microRNAs (miRNAs) participate in this process as post‑transcriptional regulators, however the mechanism remains unclear. In the present study, mouse VSMCs (mVSMCs) harvested from aortas were cultured in normoxic and hypoxic conditions, and the mRNA levels of miR-26b-5p, desmin, H‑caldesmon and smoothelin were quantified using reverse transcription‑quantitative polymerase chain reaction. Following treatment with a miR‑26b‑5p antagonist (agomir) or non‑targeting control (scramble), the cell areas of normoxic and hypoxic mVSMCs were analyzed by immunofluorescence staining. In addition, the protein expression levels of collagen Iα, Smad2/phosphorylated (p)‑Smad2, Smad3/p‑Smad3 and Smad4 were determined by western blotting. Potential miRNA26b‑5p binding sequences in the 3'‑untranslated region (UTR) of Smad4 were investigated, and the distribution of Smad4 in mVSMCs was visualized using immunofluorescence methods. Hypoxic mVSMCs exhibited a significant downregulation miR‑26b‑5p, upregulation of hypoxia inducible factor‑1α mRNA and suppression of desmin, H‑caldesmon and smoothelin mRNA levels. Additionally, miR‑26b‑5p agomir reduced the cell area and decreased collagen Iα expression levels in hypoxic mVSMCs compared with normoxic mVSMCs transfected with agomir, and the area was comparable with those of normoxic mVSMCs transfected with agomir or scramble. Furthermore, miR‑26b‑5p suppressed Smad4 expression in hypoxic mVSMCs, but did not change the expression levels of Smad2 and Smad3, p‑Smad2 and p‑Smad3, however p‑Smad2 and p‑Smad3 levels were upregulated in response to hypoxic stimuli. Additionally, the miR‑26b‑5p agomir caused weak immunoreactivity with Smad4 in hypoxic mVSMCs. The binding motif of miR‑26b‑5p in the Smad4 3'‑UTR was identified as UACUUGA at position 978-984. These findings suggest that miR‑26b‑5p regulates hypoxia‑induced phenotypic switching of VSMCs via the transforming growth factor β/Smad4 signaling pathway.

Contribution of elevated intracellular calcium to pulmonary arterial myocyte alkalinization during chronic hypoxia

PubMed Central

Luke, Trevor; Shimoda, Larissa A.

2016-01-01

Abstract In the lung, exposure to chronic hypoxia (CH) causes pulmonary hypertension, a debilitating disease. Development of this condition arises from increased muscularity and contraction of pulmonary vessels, associated with increases in pulmonary arterial smooth muscle cell (PASMC) intracellular pH (pHi) and Ca2+ concentration ([Ca2+]i). In this study, we explored the interaction between pHi and [Ca2+]i in PASMCs from rats exposed to normoxia or CH (3 weeks, 10% O2). PASMC pHi and [Ca2+]i were measured with fluorescent microscopy and the dyes BCECF and Fura-2. Both pHi and [Ca2+]i levels were elevated in PASMCs from hypoxic rats. Exposure to KCl increased [Ca2+]i and pHi to a similar extent in normoxic and hypoxic PASMCs. Conversely, removal of extracellular Ca2+ or blockade of Ca2+ entry with NiCl2 or SKF 96365 decreased [Ca2+]i and pHi only in hypoxic cells. Neither increasing pHi with NH4Cl nor decreasing pHi by removal of bicarbonate impacted PASMC [Ca2+]i. We also examined the roles of Na+/Ca2+ exchange (NCX) and Na+/H+ exchange (NHE) in mediating the elevated basal [Ca2+]i and Ca2+-dependent changes in PASMC pHi. Bepridil, dichlorobenzamil, and KB-R7943, which are NCX inhibitors, decreased resting [Ca2+]i and pHi only in hypoxic PASMCs and blocked the changes in pHi induced by altering [Ca2+]i. Exposure to ethyl isopropyl amiloride, an NHE inhibitor, decreased resting pHi and prevented changes in pHi due to changing [Ca2+]i. Our findings indicate that, during CH, the elevation in basal [Ca2+]i may contribute to the alkaline shift in pHi in PASMCs, likely via mechanisms involving reverse-mode NCX and NHE. PMID:27076907

Opiorphin is a master regulator of the hypoxic response in corporal smooth muscle cells.

PubMed

Fu, Shibo; Tar, Moses Tarndie; Melman, Arnold; Davies, Kelvin Paul

2014-08-01

Men with sickle cell disease (SCD) risk developing priapism. Recognizing that SCD is a disease of hypoxia, we investigated the effect of hypoxia on gene expression in corporal smooth muscle (CSM) cells. Rat CSM cells in vitro were treated with CoCl2 or low oxygen tension to mimic hypoxia. Hypoxic conditions increased expression of genes previously associated with priapism in animal models. Variable coding sequence a1 (Vcsa1; the rat opiorphin homologue, sialorphin), hypoxia-inducible factor 1a (Hif-1a), and A2B adenosine receptor (a2br) were increased by 10-, 4-, and 6-fold, respectively, by treatment with CoCl2, whereas low oxygen tension caused increases in expression of 3-, 4-, and 1.5-fold, respectively. Sialorphin-treated CSM cells increased expression of Hif-1a and a2br by 4-fold, and vcsa1-siRNA treatment reduced expression by ∼50%. Using a Hif-1a inhibitor, we demonstrated up-regulation of a2br by sialorphin is dependent on Hif-1a, and knockdown of vcsa1 expression with vcsa1-siRNA demonstrated that hypoxic-up-regulation of Hif-1a is dependent on vcsa1. In CSM from a SCD mouse, there was 15-fold up-regulation of opiorphin at a life stage prior to priapism. We conclude that in CSM, opiorphins are master regulators of the hypoxic response. Opiorphin up-regulation in response to SCD-associated hypoxia activates CSM "relaxant" pathways; excessive activation of these pathways results in priapism. © FASEB.

Adenosine A2B receptor modulates intestinal barrier function under hypoxic and ischemia/reperfusion conditions.

PubMed

Yang, Yang; Qiu, Yuan; Wang, Wensheng; Xiao, Weidong; Liang, Hongyin; Zhang, Chaojun; Yang, Hanwenbo; Teitelbaum, Daniel H; Sun, Li-Hua; Yang, Hua

2014-01-01

Intestinal barrier function failure from ischemia/reperfusion (I/R) and acute hypoxia has been implicated as a critical determinant in the predisposition to intestinal inflammation and a number of inflammatory disorders. Here, we identified the role of Adenosine A2B receptor (A2BAR) in the regulation of intestinal barrier function under I/R and acute hypoxic conditions. C57BL/6J mice were used, and were randomized into three groups: Sham, I/R, IR+PSB1115 (a specific A2BAR antagonist) groups. After surgery, the small bowel was harvested for immunohistochemical staining, RNA and protein content, and intestinal permeability analyses. Using an epithelial cell culture model, we investigated the influence of hypoxia on the epithelial function, and the role of A2BAR in the expressions of tight junction and epithelial permeability. The expressions of Claudin-1, occludin and ZO-1 were detected by RT-PCR and Western-Blot. Epithelial barrier function was assessed with transepithelial resistance (TER). The A2BAR antagonist, PSB1115, significantly increased tight junction protein expression after intestinal I/R or acute hypoxia conditions. PSB1115 also attenuated the disrupted distribution of TJ proteins. Furthermore, inhibition of A2BAR attenuated the decrease in TER induced by I/R or acute hypoxic conditions, and maintained intestinal barrier function. Antagonism of A2BAR activity improves intestinal epithelial structure and barrier function in a mouse model of intestinal I/R and a cell model of acute hypoxia. These findings support a potentially destructive role for A2BAR under intestinal I/R and acute hypoxic conditions.

Metabolomic Analysis of Anti-Hypoxia and Anti-anxiety Effects of Fu Fang Jin Jing Oral Liquid

PubMed Central

Guan, Shuhong; Feng, Ruihong; Zhang, Hui; Liu, Qiuhong; Sun, Peng; Lin, Donghai; Zhang, Naixia; Shen, Jun

2013-01-01

Background Herba Rhodiolae is a traditional Chinese medicine used by the Tibetan people for treating hypoxia related diseases such as anxiety. Based on the previous work, we developed and patented an anti-anxiety herbal formula Fu Fang Jin Jing Oral Liquid (FJJOL) with Herba Rhodiolae as a chief ingredient. In this study, the anti-hypoxia and anti-anxiety effects of FJJOL in a high altitude forced-swimming mouse model with anxiety symptoms will be elucidated by NMR-based metabolomics. Methods In our experiments, the mice were divided randomly into four groups as flatland group, high altitude saline-treated group, high altitude FJJOL-treated group, and high altitude diazepam-treated group. To cause anxiety effects and hypoxic defects, a combination use of oxygen level decreasing (hypobaric cabin) and oxygen consumption increasing (exhaustive swimming) were applied to mice. After a three-day experimental handling, aqueous metabolites of mouse brain tissues were extracted and then subjected to NMR analysis. The therapeutic effects of FJJOL on the hypobaric hypoxia mice with anxiety symptoms were verified. Results Upon hypoxic exposure, both energy metabolism defects and disorders of functional metabolites in brain tissues of mice were observed. PCA, PLS-DA and OPLS-DA scatter plots revealed a clear group clustering for metabolic profiles in the hypoxia versus normoxia samples. After a three-day treatment with FJJOL, significant rescue effects on energy metabolism were detected, and levels of ATP, fumarate, malate and lactate in brain tissues of hypoxic mice recovered. Meanwhile, FJJOL also up-regulated the neurotransmitter GABA, and the improvement of anxiety symptoms was highly related to this effect. Conclusions FJJOL ameliorated hypobaric hypoxia effects by regulating energy metabolism, choline metabolism, and improving the symptoms of anxiety. The anti-anxiety therapeutic effects of FJJOL were comparable to the conventional anti-anxiety drug diazepam on the hypobaric hypoxia mice. FJJOL might serve as an alternative therapy for the hypoxia and anxiety disorders. PMID:24205180

Metabolomic analysis of anti-hypoxia and anti-anxiety effects of Fu Fang Jin Jing Oral Liquid.

PubMed

Liu, Xia; Zhu, Wei; Guan, Shuhong; Feng, Ruihong; Zhang, Hui; Liu, Qiuhong; Sun, Peng; Lin, Donghai; Zhang, Naixia; Shen, Jun

2013-01-01

Herba Rhodiolae is a traditional Chinese medicine used by the Tibetan people for treating hypoxia related diseases such as anxiety. Based on the previous work, we developed and patented an anti-anxiety herbal formula Fu Fang Jin Jing Oral Liquid (FJJOL) with Herba Rhodiolae as a chief ingredient. In this study, the anti-hypoxia and anti-anxiety effects of FJJOL in a high altitude forced-swimming mouse model with anxiety symptoms will be elucidated by NMR-based metabolomics. In our experiments, the mice were divided randomly into four groups as flatland group, high altitude saline-treated group, high altitude FJJOL-treated group, and high altitude diazepam-treated group. To cause anxiety effects and hypoxic defects, a combination use of oxygen level decreasing (hypobaric cabin) and oxygen consumption increasing (exhaustive swimming) were applied to mice. After a three-day experimental handling, aqueous metabolites of mouse brain tissues were extracted and then subjected to NMR analysis. The therapeutic effects of FJJOL on the hypobaric hypoxia mice with anxiety symptoms were verified. Upon hypoxic exposure, both energy metabolism defects and disorders of functional metabolites in brain tissues of mice were observed. PCA, PLS-DA and OPLS-DA scatter plots revealed a clear group clustering for metabolic profiles in the hypoxia versus normoxia samples. After a three-day treatment with FJJOL, significant rescue effects on energy metabolism were detected, and levels of ATP, fumarate, malate and lactate in brain tissues of hypoxic mice recovered. Meanwhile, FJJOL also up-regulated the neurotransmitter GABA, and the improvement of anxiety symptoms was highly related to this effect. FJJOL ameliorated hypobaric hypoxia effects by regulating energy metabolism, choline metabolism, and improving the symptoms of anxiety. The anti-anxiety therapeutic effects of FJJOL were comparable to the conventional anti-anxiety drug diazepam on the hypobaric hypoxia mice. FJJOL might serve as an alternative therapy for the hypoxia and anxiety disorders.

Behavioural effects of near-term acute fetal hypoxia in a small precocial animal, the spiny mouse (Acomys cahirinus).

PubMed

Ireland, Zoe; Dickinson, Hayley; Fleiss, Bobbi; Hutton, Lisa C; Walker, David W

2010-01-01

We have previously developed a model of near-term intra-uterine hypoxia producing significant neonatal mortality (37%) in a small laboratory animal - the spiny mouse - which has precocial offspring at birth. The aim of the present study was to determine if this insult resulted in the appearance of behavioural abnormalities in those offspring which survived the hypoxic delivery. Behavioural tests assessed gait (using footprint patterns), motor coordination and balance on an accelerating rotarod, and spontaneous locomotion and exploration in an open field. We found that the near-term acute hypoxic episode produced a mild neurological deficit in the early postnatal period. In comparison to vaginally delivered controls, hypoxia pups were able to remain on the accelerating rotarod for significantly shorter durations on postnatal days 1-2, and in the open field they travelled significantly shorter distances, jumped less, and spent a greater percentage of time stationary on postnatal days 5 and 15. No changes were observed in gait. Unlike some rodent models of cerebral hypoxia-ischaemia, macroscopic examination of the brain on postnatal day 5 showed no gross cystic lesions, oedema or infarct. Future studies should be directed at identifying hypoxia-induced alterations in the function of specific brain regions, and assessing if maternal administration of neuroprotective agents can prevent against hypoxia-induced neurological deficits and brain damage that occur at birth. Copyright 2009 S. Karger AG, Basel.

Simulating Heterogeneous Tumor Cell Populations

PubMed Central

Bar-Sagi, Dafna; Mishra, Bud

2016-01-01

Certain tumor phenomena, like metabolic heterogeneity and local stable regions of chronic hypoxia, signify a tumor’s resistance to therapy. Although recent research has shed light on the intracellular mechanisms of cancer metabolic reprogramming, little is known about how tumors become metabolically heterogeneous or chronically hypoxic, namely the initial conditions and spatiotemporal dynamics that drive these cell population conditions. To study these aspects, we developed a minimal, spatially-resolved simulation framework for modeling tissue-scale mixed populations of cells based on diffusible particles the cells consume and release, the concentrations of which determine their behavior in arbitrarily complex ways, and on stochastic reproduction. We simulate cell populations that self-sort to facilitate metabolic symbiosis, that grow according to tumor-stroma signaling patterns, and that give rise to stable local regions of chronic hypoxia near blood vessels. We raise two novel questions in the context of these results: (1) How will two metabolically symbiotic cell subpopulations self-sort in the presence of glucose, oxygen, and lactate gradients? We observe a robust pattern of alternating striations. (2) What is the proper time scale to observe stable local regions of chronic hypoxia? We observe the stability is a function of the balance of three factors related to O2—diffusion rate, local vessel release rate, and viable and hypoxic tumor cell consumption rate. We anticipate our simulation framework will help researchers design better experiments and generate novel hypotheses to better understand dynamic, emergent whole-tumor behavior. PMID:28030620

Hepatic transcriptomic and metabolic responses of hybrid striped bass to acute and chronic hypoxic insult

USDA-ARS?s Scientific Manuscript database

Striped bass (Morone saxatilis), white bass (Morone chrysops), and their hybrid are an important group of recreational and farmed species in the United States. Regardless of habitat, it is not uncommon for fish of the genus Morone to encounter and cope with conditions of scarce oxygen availability....

Hepatic transcriptomic and metabolic responses of hybrid striped bass (Morone chrysops) to acute and chronic hypoxic insult

USDA-ARS?s Scientific Manuscript database

Hypoxia is a state of oxygen deficiency that can lead to impairment of organismal function or in extreme cases, death. Irrespective of their environment, at some point in their life cycle farmed fish will likely experience varying degrees of hypoxia, particularly during summer months. The temperat...

Targeted expression of heme oxygenase-1 prevents the pulmonary inflammatory and vascular responses to hypoxia

NASA Astrophysics Data System (ADS)

Minamino, Tohru; Christou, Helen; Hsieh, Chung-Ming; Liu, Yuxiang; Dhawan, Vijender; Abraham, Nader G.; Perrella, Mark A.; Mitsialis, S. Alex; Kourembanas, Stella

2001-07-01

Chronic hypoxia causes pulmonary hypertension with smooth muscle cell proliferation and matrix deposition in the wall of the pulmonary arterioles. We demonstrate here that hypoxia also induces a pronounced inflammation in the lung before the structural changes of the vessel wall. The proinflammatory action of hypoxia is mediated by the induction of distinct cytokines and chemokines and is independent of tumor necrosis factor- signaling. We have previously proposed a crucial role for heme oxygenase-1 (HO-1) in protecting cardiomyocytes from hypoxic stress, and potent anti-inflammatory properties of HO-1 have been reported in models of tissue injury. We thus established transgenic mice that constitutively express HO-1 in the lung and exposed them to chronic hypoxia. HO-1 transgenic mice were protected from the development of both pulmonary inflammation as well as hypertension and vessel wall hypertrophy induced by hypoxia. Significantly, the hypoxic induction of proinflammatory cytokines and chemokines was suppressed in HO-1 transgenic mice. Our findings suggest an important protective function of enzymatic products of HO-1 activity as inhibitors of hypoxia-induced vasoconstrictive and proinflammatory pathways.

Chronic hypoxia and low salinity impair anti-predatory responses of the green-lipped mussel Perna viridis.

PubMed

Wang, Youji; Hu, Menghong; Cheung, S G; Shin, P K S; Lu, Weiqun; Li, Jiale

2012-06-01

The effects of chronic hypoxia and low salinity on anti-predatory responses of the green-lipped mussel Perna viridis were investigated. Dissolved oxygen concentrations ranged from hypoxic to normoxic (1.5 ± 0.3 mg l(-1), 3.0 ± 0.3 mg l(-1) and 6.0 ± 0.3 mg l(-1)), and salinities were selected within the variation during the wet season in Hong Kong coastal waters (15‰, 20‰, 25‰ and 30‰). The dissolved oxygen and salinity significantly affected some anti-predatory responses of mussel, including byssus production, shell thickness and shell weight, and the adductor diameter was only significantly affected by salinity. Besides, interactive effects of dissolved oxygen and salinity on the byssus production and shell thickness were also observed. In hypoxic and low salinity conditions, P. viridis produced fewer byssal threads, thinner shell and adductor muscle, indicating that hypoxia and low salinity are severe environmental stressors for self-defence of mussel, and their interactive effects further increase the predation risk. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Extract from Mimosa pigra attenuates chronic experimental pulmonary hypertension.

PubMed

Rakotomalala, G; Agard, C; Tonnerre, P; Tesse, A; Derbré, S; Michalet, S; Hamzaoui, J; Rio, M; Cario-Toumaniantz, C; Richomme, P; Charreau, B; Loirand, G; Pacaud, P

2013-06-21

Different parts of Mimosa pigra (MPG) are used in traditional medicine in Madagascar, tropical Africa, South America and Indonesia for various troubles including cardiovascular disorders. To investigate the mechanisms underlying the vascular effects of MPG by assessing in vitro its antioxidant and anti-inflammatory properties, and its vascular relaxing effects, and in vivo, its action on hypoxic pulmonary hypertension (PAH) in rats. The antioxidant activity of MPG leaf hydromethanolic extract was determined by using both the 1,1-diphenyl-2-picrylhydrazyl radical scavenging and the oxygen radical absorbance capacity in vitro assays. Anti-inflammatory properties were assayed on TNFα-induced VCAM-1 expression in endothelial cells. The vasorelaxant effect of MPG extract was studied on rat arterial rings pre-contracted with phenylephrine (1μM) in the presence or absence of the endothelium. In vivo MPG extract effects were analyzed in chronic hypoxic PAH, obtained by housing male Wistar rats, orally treated or not with MPG extract (400mg/kg/d), in a hypobaric chamber for 21 days. MPG leaf extract had antioxidant and anti-inflammatory properties. It induced endothelium-dependent, NO-mediated relaxation of rat aorta and pulmonary artery. In vivo, chronic MPG treatment reduced hypoxic PAH in rat by decreasing by 22.3% the pulmonary arterial pressure and by 20.0% and 23.9% the pulmonary artery and cardiac remodelling, respectively. This effect was associated with a restoration of endothelium function and a 2.3-fold increase in endothelial NO synthase phosphorylation. MPG leaf hydromethanolic extract contained tryptophan and flavonoids, including quercetin glycosides. Both compounds also efficiently limit hypoxia-induced PAH. Our results show endothelial protective action of MPG leaf hydromethanolic extract which is likely to be due to its antioxidant action. MPG successfully attenuated the development of PAH, thus demonstrating the protective effect of MPG on cardiovascular diseases. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Exposure of European sea bass (Dicentrarchus labrax) to chemically dispersed oil has a chronic residual effect on hypoxia tolerance but not aerobic scope.

PubMed

Zhang, Yangfan; Mauduit, Florian; Farrell, Anthony P; Chabot, Denis; Ollivier, Hélène; Rio-Cabello, Adrien; Le Floch, Stéphane; Claireaux, Guy

2017-10-01

We tested the hypothesis that the chronic residual effects of an acute exposure of European sea bass (Dicentrarchus labrax) to chemically dispersed crude oil is manifest in indices of hypoxic performance rather than aerobic performance. Sea bass were pre-screened with a hypoxia challenge test to establish their incipient lethal oxygen saturation (ILOS), but on discovering a wide breadth for individual ILOS values (2.6-11.0% O 2 saturation), fish were subsequently subdivided into either hypoxia sensitive (HS) or hypoxia tolerant (HT) phenotypes, traits that were shown to be experimentally repeatable. The HT phenotype had a lower ILOS and critical oxygen saturation (O 2crit ) compared with the HS phenotype and switched to glycolytic metabolism at a lower dissolved oxygen, even though both phenotypes accumulated lactate and glucose to the same plasma concentrations at ILOS. As initially hypothesized, and regardless of the phenotype considered, we found no residual effect of oil on any of the indices of aerobic performance. Contrary to our hypothesis, however, oil exposure had no residual effect on any of the indices of hypoxic performance in the HS phenotype. In the HT phenotype, on the other hand, oil exposure had residual effects as illustrated by the impaired repeatability of hypoxia tolerance and also by the 24% increase in O 2crit , the 40% increase in scope for oxygen deficit, the 17% increase in factorial scope for oxygen deficit and the 57% increase in accumulated oxygen deficit. Thus, sea bass with a HT phenotype remained chronically impaired for a minimum of 167days following an acute 24-h oil exposure while the HS phenotypes did not. We reasoned that impaired oxygen extraction at gill due to oil exposure activates glycolytic metabolism at a higher dissolved oxygen, conferring on the HT phenotype an inferior hypoxia resistance that might eventually compromise their ability to survive hypoxic episodes. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Early Life Exposure to Chronic Intermittent Hypoxia Primes Increased Susceptibility to Hypoxia-Induced Weakness in Rat Sternohyoid Muscle during Adulthood

PubMed Central

McDonald, Fiona B.; Dempsey, Eugene M.; O'Halloran, Ken D.

2016-01-01

Intermittent hypoxia is a feature of apnea of prematurity (AOP), chronic lung disease, and sleep apnea. Despite the clinical relevance, the long-term effects of hypoxic exposure in early life on respiratory control are not well defined. We recently reported that exposure to chronic intermittent hypoxia (CIH) during postnatal development (pCIH) causes upper airway muscle weakness in both sexes, which persists for several weeks. We sought to examine if there are persistent sex-dependent effects of pCIH on respiratory muscle function into adulthood and/or increased susceptibility to re-exposure to CIH in adulthood in animals previously exposed to CIH during postnatal development. We hypothesized that pCIH would cause long-lasting muscle impairment and increased susceptibility to subsequent hypoxia. Within 24 h of delivery, pups and their respective dams were exposed to CIH: 90 s of hypoxia reaching 5% O2 at nadir; once every 5 min, 8 h per day for 3 weeks. Sham groups were exposed to normoxia in parallel. Three groups were studied: sham; pCIH; and pCIH combined with adult CIH (p+aCIH), where a subset of the pCIH-exposed pups were re-exposed to the same CIH paradigm beginning at 13 weeks. Following gas exposures, sternohyoid and diaphragm muscle isometric contractile and endurance properties were examined ex vivo. There was no apparent lasting effect of pCIH on respiratory muscle function in adults. However, in both males and females, re-exposure to CIH in adulthood in pCIH-exposed animals caused sternohyoid (but not diaphragm) weakness. Exposure to this paradigm of CIH in adulthood alone had no effect on muscle function. Persistent susceptibility in pCIH-exposed airway dilator muscle to subsequent hypoxic insult may have implications for the control of airway patency in adult humans exposed to intermittent hypoxic stress during early life. PMID:26973537

Long non-coding RNA expression patterns in lung tissues of chronic cigarette smoke induced COPD mouse model.

PubMed

Zhang, Haiyun; Sun, Dejun; Li, Defu; Zheng, Zeguang; Xu, Jingyi; Liang, Xue; Zhang, Chenting; Wang, Sheng; Wang, Jian; Lu, Wenju

2018-05-15

Long non-coding RNAs (lncRNAs) have critical regulatory roles in protein-coding gene expression. Aberrant expression profiles of lncRNAs have been observed in various human diseases. In this study, we investigated transcriptome profiles in lung tissues of chronic cigarette smoke (CS)-induced COPD mouse model. We found that 109 lncRNAs and 260 mRNAs were significantly differential expressed in lungs of chronic CS-induced COPD mouse model compared with control animals. GO and KEGG analyses indicated that differentially expressed lncRNAs associated protein-coding genes were mainly involved in protein processing of endoplasmic reticulum pathway, and taurine and hypotaurine metabolism pathway. The combination of high throughput data analysis and the results of qRT-PCR validation in lungs of chronic CS-induced COPD mouse model, 16HBE cells with CSE treatment and PBMC from patients with COPD revealed that NR_102714 and its associated protein-coding gene UCHL1 might be involved in the development of COPD both in mouse and human. In conclusion, our study demonstrated that aberrant expression profiles of lncRNAs and mRNAs existed in lungs of chronic CS-induced COPD mouse model. From animal models perspective, these results might provide further clues to investigate biological functions of lncRNAs and their potential target protein-coding genes in the pathogenesis of COPD.

Chronic alcohol intake promotes tumor growth in a diethylnitrosamine-induced hepatocarcinogenesis mouse model through increased Wnt/Beta-catenin signaling

USDA-ARS?s Scientific Manuscript database

Ethanol (EtOH) metabolism is involved in both initiating and promoting mechanisms in hepatocellular carcinoma progression in chronic alcoholics. In this study, we developed a mouse model to test the hypothesis that chronic EtOH consumption promotes tumor growth irrespective of EtOH-related initiati...

Post-natal hypoxic activity of the central respiratory command is improved in transgenic mice overexpressing Epo in the brain.

PubMed

Caravagna, Céline; Kinkead, Richard; Soliz, Jorge

2014-08-15

Previous studies indicated that erythropoietin modulates central respiratory command in mice. Specifically, a one-hour incubation of the brainstems with erythropoietin attenuates hypoxia-induced central respiratory depression. Here, using transgenic mice constitutively overexpressing erythropoietin specifically in the brain (Tg21), we investigated the effect of chronic erythropoietin stimulation on central respiratory command activity during post-natal development. In vitro brainstem-spinal cord preparations from mice at 0 (P0) or 3 days of age (P3) were used to record the fictive inspiratory activity from the C4 ventral root. Our results show that erythropoietin already stimulates the hypoxic burst frequency at P0, and at P3, erythropoietin effectively stimulates the hypoxic burst frequency and amplitude. Because the maturation of the central respiratory command in mice is characterized by a decrease in the burst frequency with age, our results also suggest that erythropoietin accelerates the maturation of the newborn respiratory network and its response to hypoxia. Copyright © 2014 Elsevier B.V. All rights reserved.

Mesenchymal stromal cells reverse hypoxia-mediated suppression of α-smooth muscle actin expression in human dermal fibroblasts.

PubMed

Faulknor, Renea A; Olekson, Melissa A; Nativ, Nir I; Ghodbane, Mehdi; Gray, Andrea J; Berthiaume, François

2015-02-27

During wound healing, fibroblasts deposit extracellular matrix that guides angiogenesis and supports the migration and proliferation of cells that eventually form the scar. They also promote wound closure via differentiation into α-smooth muscle actin (SMA)-expressing myofibroblasts, which cause wound contraction. Low oxygen tension typical of chronic nonhealing wounds inhibits fibroblast collagen production and differentiation. It has been suggested that hypoxic mesenchymal stromal cells (MSCs) secrete factors that promote wound healing in animal models; however, it is unclear whether these factors are equally effective on the target cells in a hypoxic wound environment. Here we investigated the impact of MSC-derived soluble factors on the function of fibroblasts cultured in hypoxic fibroblast-populated collagen lattices (FPCLs). Hypoxia alone significantly decreased FPCL contraction and α-SMA expression. MSC-conditioned medium restored hypoxic FPCL contraction and α-SMA expression to levels similar to normoxic FPCLs. SB431542, an inhibitor of transforming growth factor-β1 (TGF-β1)-mediated signaling, blocked most of the MSC effect on FPCL contraction, while exogenous TGF-β1 at levels similar to that secreted by MSCs reproduced the MSC effect. These results suggest that TGF-β1 is a major paracrine signal secreted by MSCs that can restore fibroblast functions relevant to the wound healing process and that are impaired in hypoxia. Copyright © 2015. Published by Elsevier Inc.

Does “Live High-Train Low (and High)” Hypoxic Training Alter Running Mechanics In Elite Team-sport Players?

PubMed Central

Girard, Olivier; Millet, Grégoire P.; Morin, Jean-Benoit; Brocherie, Franck

2017-01-01

This study aimed to investigate if “Live High-Train Low (and High)” hypoxic training alters constant-velocity running mechanics. While residing under normobaric hypoxia (≥14 h·d-1; FiO2 14.5-14.2%) for 14 days, twenty field hockey players performed, in addition to their usual training in normoxia, six sessions (4 × 5 × 5-s maximal sprints; 25 s passive recovery; 5 min rest) under either normobaric hypoxia (FiO2 ~14.5%, n = 9) or normoxia (FiO2 20.9%, n = 11). Before and immediately after the intervention, their running pattern was assessed at 10 and 15 km·h-1 as well as during six 30-s runs at ~20 km·h-1 with 30-s passive recovery on an instrumented motorised treadmill. No clear changes in running kinematics and spring-mass parameters occurred globally either at 10, 15 or ~20 km·h-1, with also no significant time × condition interaction for any parameters (p > 0.14). Independently of the condition, heart rate (all p < 0.05) and ratings of perceived exertion decreased post-intervention (only at 15 km·h-1, p < 0.05). Despite indirect signs for improved psycho-physiological responses, no forthright change in stride mechanical pattern occurred after “Live High-Train Low (and High)” hypoxic training. Key points There are indirect signs for improved psycho-physiological responses in responses to “Live High-Train Low (and High)” hypoxic training. This hypoxic training regimen, however, does not modify the running mechanics of elite team-sport players at low and high velocities. Coaches can be confident that this intervention, known for inducing significant metabolic benefits, is appropriate for athletes since their running kinetics and kinematics are not negatively affected by chronic hypoxic exposure. PMID:28912649

Generation of neural progenitor cells by chemical cocktails and hypoxia

PubMed Central

Cheng, Lin; Hu, Wenxiang; Qiu, Binlong; Zhao, Jian; Yu, Yongchun; Guan, Wuqiang; Wang, Min; Yang, Wuzhou; Pei, Gang

2014-01-01

Neural progenitor cells (NPCs) can be induced from somatic cells by defined factors. Here we report that NPCs can be generated from mouse embryonic fibroblasts by a chemical cocktail, namely VCR (V, VPA, an inhibitor of HDACs; C, CHIR99021, an inhibitor of GSK-3 kinases and R, Repsox, an inhibitor of TGF-β pathways), under a physiological hypoxic condition. These chemical-induced NPCs (ciNPCs) resemble mouse brain-derived NPCs regarding their proliferative and self-renewing abilities, gene expression profiles, and multipotency for different neuroectodermal lineages in vitro and in vivo. Further experiments reveal that alternative cocktails with inhibitors of histone deacetylation, glycogen synthase kinase, and TGF-β pathways show similar efficacies for ciNPC induction. Moreover, ciNPCs can also be induced from mouse tail-tip fibroblasts and human urinary cells with the same chemical cocktail VCR. Thus our study demonstrates that lineage-specific conversion of somatic cells to NPCs could be achieved by chemical cocktails without introducing exogenous factors. PMID:24638034

Essential role of FBXL5-mediated cellular iron homeostasis in maintenance of hematopoietic stem cells

PubMed Central

Muto, Yoshiharu; Nishiyama, Masaaki; Nita, Akihiro; Moroishi, Toshiro; Nakayama, Keiichi I.

2017-01-01

Hematopoietic stem cells (HSCs) are maintained in a hypoxic niche to limit oxidative stress. Although iron elicits oxidative stress, the importance of iron homeostasis in HSCs has been unknown. Here we show that iron regulation by the F-box protein FBXL5 is required for HSC self-renewal. Conditional deletion of Fbxl5 in mouse HSCs results in cellular iron overload and a reduced cell number. Bone marrow transplantation reveals that FBXL5-deficient HSCs are unable to reconstitute the hematopoietic system of irradiated recipients as a result of stem cell exhaustion. Transcriptomic analysis shows abnormal activation of oxidative stress responses and the cell cycle in FBXL5-deficient mouse HSCs as well as downregulation of FBXL5 expression in HSCs of patients with myelodysplastic syndrome. Suppression of iron regulatory protein 2 (IRP2) accumulation in FBXL5-deficient mouse HSCs restores stem cell function, implicating IRP2 as a potential therapeutic target for human hematopoietic diseases associated with FBXL5 downregulation. PMID:28714470

Small Molecule Inhibition of microRNA-210 Reprograms an Oncogenic Hypoxic Circuit.

PubMed

Costales, Matthew G; Haga, Christopher L; Velagapudi, Sai Pradeep; Childs-Disney, Jessica L; Phinney, Donald G; Disney, Matthew D

2017-03-08

A hypoxic state is critical to the metastatic and invasive characteristics of cancer. Numerous pathways play critical roles in cancer maintenance, many of which include noncoding RNAs such as microRNA (miR)-210 that regulates hypoxia inducible factors (HIFs). Herein, we describe the identification of a small molecule named Targapremir-210 that binds to the Dicer site of the miR-210 hairpin precursor. This interaction inhibits production of the mature miRNA, derepresses glycerol-3-phosphate dehydrogenase 1-like enzyme (GPD1L), a hypoxia-associated protein negatively regulated by miR-210, decreases HIF-1α, and triggers apoptosis of triple negative breast cancer cells only under hypoxic conditions. Further, Targapremir-210 inhibits tumorigenesis in a mouse xenograft model of hypoxic triple negative breast cancer. Many factors govern molecular recognition of biological targets by small molecules. For protein, chemoproteomics and activity-based protein profiling are invaluable tools to study small molecule target engagement and selectivity in cells. Such approaches are lacking for RNA, leaving a void in the understanding of its druggability. We applied Chemical Cross-Linking and Isolation by Pull Down (Chem-CLIP) to study the cellular selectivity and the on- and off-targets of Targapremir-210. Targapremir-210 selectively recognizes the miR-210 precursor and can differentially recognize RNAs in cells that have the same target motif but have different expression levels, revealing this important feature for selectively drugging RNAs for the first time. These studies show that small molecules can be rapidly designed to selectively target RNAs and affect cellular responses to environmental conditions, resulting in favorable benefits against cancer. Further, they help define rules for identifying druggable targets in the transcriptome.

Tideglusib, a chemical inhibitor of GSK3β, attenuates hypoxic-ischemic brain injury in neonatal mice.

PubMed

Wang, Haitao; Huang, Sammen; Yan, Kuipo; Fang, Xiaoyan; Abussaud, Ahmed; Martinez, Ana; Sun, Hong-Shuo; Feng, Zhong-Ping

2016-10-01

Hypoxia-ischemia is an important cause of brain injury and neurological morbidity in the newborn infants. The activity of glycogen synthase kinase-3β (GSK-3β) is up-regulated following neonatal stroke. Tideglusib is a GSK-3β inhibitor which has neuroprotective effects against neurodegenerative diseases in clinical trials. However, the effect of tideglusib on hypoxic-ischemic (HI) brain injury in neonates is still unknown. Postnatal day 7 (P7) mouse pups subjected to unilateral common carotid artery ligation followed by 1h of hypoxia or sham surgery was performed. HI animals were administered tideglusib (5mg/kg) or vehicle intraperitoneally 20min prior to the onset of ischemia. The brain infarct volume and whole brain images, were used in conjunction with Nissl staining to evaluate the protective effects of tideglusib. Protein levels of glial fibrillary acidic protein (GFAP), Notch1, cleaved caspase-3/9, phosphorylated signal transducer and activator of transcription 3 (STAT3), GSK-3β and protein kinase B (Akt) were detected to identify potentially involved molecules. Tideglusib significantly reduced cerebral infarct volume at both 24h and 7days after HI injury. Tideglusib also increased phosphorylated GSK-3β(Ser9) and Akt(Ser473), and reduced the expression of GFAP and p-STAT3(Tyr705). In addition, pretreatment with tideglusib also enhanced the protein level of Notch1. Moreover, tideglusib reduced the cleavage of pro-apoptotic signal caspase proteins, including caspase 3 and caspase 9 following HI. These results indicate that tideglusib shows neuroprotection against hypoxic-ischemic brain injury in neonatal mice. Tideglusib is a potential compound for the prevention or treatment of hypoxic-ischemic brain injury in neonates. Copyright © 2016 Elsevier B.V. All rights reserved.

Mesenchymal stromal cells reverse hypoxia-mediated suppression of α-smooth muscle actin expression in human dermal fibroblasts

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

Faulknor, Renea A.; Olekson, Melissa A.; Nativ, Nir I.

During wound healing, fibroblasts deposit extracellular matrix that guides angiogenesis and supports the migration and proliferation of cells that eventually form the scar. They also promote wound closure via differentiation into α-smooth muscle actin (SMA)-expressing myofibroblasts, which cause wound contraction. Low oxygen tension typical of chronic nonhealing wounds inhibits fibroblast collagen production and differentiation. It has been suggested that hypoxic mesenchymal stromal cells (MSCs) secrete factors that promote wound healing in animal models; however, it is unclear whether these factors are equally effective on the target cells in a hypoxic wound environment. Here we investigated the impact of MSC-derived solublemore » factors on the function of fibroblasts cultured in hypoxic fibroblast-populated collagen lattices (FPCLs). Hypoxia alone significantly decreased FPCL contraction and α-SMA expression. MSC-conditioned medium restored hypoxic FPCL contraction and α-SMA expression to levels similar to normoxic FPCLs. (SB431542), an inhibitor of transforming growth factor-β{sub 1} (TGF-β{sub 1})-mediated signaling, blocked most of the MSC effect on FPCL contraction, while exogenous TGF-β{sub 1} at levels similar to that secreted by MSCs reproduced the MSC effect. These results suggest that TGF-β{sub 1} is a major paracrine signal secreted by MSCs that can restore fibroblast functions relevant to the wound healing process and that are impaired in hypoxia. - Highlights: • Fibroblasts were cultured in collagen lattices (FPCLs) as model contracting wounds. • Hypoxia decreased FPCL contraction and fibroblast α-smooth muscle actin expression. • Mesenchymal stromal cells (MSCs) restored function of hypoxic fibroblasts. • MSCs regulate fibroblast function mainly via secreted transforming growth factor-β{sub 1}.« less

Carotid body denervation prevents fasting hyperglycemia during chronic intermittent hypoxia.

PubMed

Shin, Mi-Kyung; Yao, Qiaoling; Jun, Jonathan C; Bevans-Fonti, Shannon; Yoo, Doo-Young; Han, Woobum; Mesarwi, Omar; Richardson, Ria; Fu, Ya-Yuan; Pasricha, Pankaj J; Schwartz, Alan R; Shirahata, Machiko; Polotsky, Vsevolod Y

2014-10-01

Obstructive sleep apnea causes chronic intermittent hypoxia (IH) and is associated with impaired glucose metabolism, but mechanisms are unknown. Carotid bodies orchestrate physiological responses to hypoxemia by activating the sympathetic nervous system. Therefore, we hypothesized that carotid body denervation would abolish glucose intolerance and insulin resistance induced by chronic IH. Male C57BL/6J mice underwent carotid sinus nerve dissection (CSND) or sham surgery and then were exposed to IH or intermittent air (IA) for 4 or 6 wk. Hypoxia was administered by decreasing a fraction of inspired oxygen from 20.9% to 6.5% once per minute, during the 12-h light phase (9 a.m.-9 p.m.). As expected, denervated mice exhibited blunted hypoxic ventilatory responses. In sham-operated mice, IH increased fasting blood glucose, baseline hepatic glucose output (HGO), and expression of a rate-liming hepatic enzyme of gluconeogenesis phosphoenolpyruvate carboxykinase (PEPCK), whereas the whole body glucose flux during hyperinsulinemic euglycemic clamp was not changed. IH did not affect glucose tolerance after adjustment for fasting hyperglycemia in the intraperitoneal glucose tolerance test. CSND prevented IH-induced fasting hyperglycemia and increases in baseline HGO and liver PEPCK expression. CSND trended to augment the insulin-stimulated glucose flux and enhanced liver Akt phosphorylation at both hypoxic and normoxic conditions. IH increased serum epinephrine levels and liver sympathetic innervation, and both increases were abolished by CSND. We conclude that chronic IH induces fasting hyperglycemia increasing baseline HGO via the CSN sympathetic output from carotid body chemoreceptors, but does not significantly impair whole body insulin sensitivity. Copyright © 2014 the American Physiological Society.

Cloning, cell-type specificity, and regulatory function of the mouse alpha(1B)-adrenergic receptor promoter.

PubMed

Zuscik, M J; Piascik, M T; Perez, D M

1999-12-01

The functionality of a 3422-base pair promoter fragment from the mouse alpha(1B)-adrenergic receptor (alpha(1B)AR) gene was examined. This fragment, cloned from a mouse genomic library, was found to have significant sequence homology to the known human and rat alpha(1B)AR promoters. However, the consensus motif of several key cis-acting elements is not conserved among the rat, human, and mouse genes, suggesting species specificity. Confirming fidelity of the murine promoter, robust in vitro expression of a chloramphenicol acetyltransferase (CAT) reporter was detected in known alpha(1B)AR-expressing BC(3)H1, NB41A3, and DDT(1)MF-2 cells transiently transfected with a promoter-CAT construct. Conversely, minimal CAT expression was detected in known alpha(1B)AR-negative RAT-1 and R3T3 cells. These findings were extended by transfecting the same promoter-CAT construct into various primary cell types. In support of the hypothesis that alpha(1)ARs are differentially expressed in the smooth muscle of the vasculature, primary cultures of superior mesenteric and renal artery vascular smooth muscle cells showed significantly stronger CAT expression than did vascular smooth muscle cells derived from pulmonary, femoral, and iliac arteries. Primary osteoblastic bone-forming cells, which are known to be alpha(1B)AR negative, showed minimal CAT expression. Indicating regulatory function through cis-acting elements, RAT-1, R3T3, NB41A3, BC(3)H1, and DDT(1)MF2 cells transfected with the promoter-CAT construct all showed increased CAT production when challenged with forskolin or hypoxic conditions. Additionally, tissue-specific regulation of the promoter was observed when cells were simultaneously challenged with both forskolin and hypoxia. These results collectively demonstrate that a 3.4-kb PvuII fragment of the murine alpha(1B)AR gene promoter can: 1) drive tissue-specific production of a CAT reporter in both clonal and primary cell lines; and 2) confer tissue-specific regulation of that CAT reporter when induced by challenge with forskolin and/or hypoxic conditions.

UPLC-QTOFMS-based metabolomic analysis of the serum of hypoxic preconditioning mice

PubMed Central

Liu, Jie; Zhang, Gang; Chen, Dewei; Chen, Jian; Yuan, Zhi-Bin; Zhang, Er-Long; Gao, Yi-Xing; Xu, Gang; Sun, Bing-Da; Liao, Wenting; Gao, Yu-Qi

2017-01-01

Hypoxic preconditioning (HPC) is well-known to exert a protective effect against hypoxic injury; however, the underlying molecular mechanism remains unclear. The present study utilized a serum metabolomics approach to detect the alterations associated with HPC. In the present study, an animal model of HPC was established by exposing adult BALB/c mice to acute repetitive hypoxia four times. The serum samples were collected by orbital blood sampling. Metabolite profiling was performed using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS), in conjunction with univariate and multivariate statistical analyses. The results of the present study confirmed that the HPC mouse model was established and refined, suggesting significant differences between the control and HPC groups at the molecular levels. HPC caused significant metabolic alterations, as represented by the significant upregulation of valine, methionine, tyrosine, isoleucine, phenylalanine, lysophosphatidylcholine (LysoPC; 16:1), LysoPC (22:6), linoelaidylcarnitine, palmitoylcarnitine, octadecenoylcarnitine, taurine, arachidonic acid, linoleic acid, oleic acid and palmitic acid, and the downregulation of acetylcarnitine, malate, citrate and succinate. Using MetaboAnalyst 3.0, a number of key metabolic pathways were observed to be acutely perturbed, including valine, leucine and isoleucine biosynthesis, in addition to taurine, hypotaurine, phenylalanine, linoleic acid and arachidonic acid metabolism. The results of the present study provided novel insights into the mechanisms involved in the acclimatization of organisms to hypoxia, and demonstrated the protective mechanism of HPC. PMID:28901489

Alterations of hypoxia-inducible factor-1 alpha in the hippocampus of mice acutely and repeatedly exposed to hypoxia.

PubMed

Shao, Guo; Gao, Cui-Ying; Lu, Guo-Wei

2005-01-01

This work aims at investigating the effects of hypoxic preconditioning on hypoxia-inducible factor-1 alpha (HIF-1alpha) expression in the hippocampus of mice during acute and repeated hypoxic exposures. The mice were randomly divided into three groups and exposed, respectively, to hypoxia for 4 runs (group H4), 1 run (group H1), and 0 run (group H0). Reverse transcription-polymerase chain reaction (RT-PCR), Western blot, electrophoretic mobility shift assay (EMSA), and chromatin immunoprecipitation were used to examine the HIF-1alpha responses in the mouse hippocampus following exposure to hypoxia. The tolerance of mice to hypoxia increased significantly following acute and repetitive exposure to autoprogressive hypoxia. Total mRNA, total protein, and nuclear protein were extracted from the hippocampus for RT-PCR, Western blot, and EMSA, respectively. The HIF-1alpha mRNA levels were found to be increased in group H1 and decreased in group H4. The HIF-1alpha protein levels and HIF-1 DNA-binding activities were increased in group H1 and markedly increased in group H4. One of the HIF-1 target genes, vascular endothelial growth factor, increased in group H4. HIF-1 activation is thought to be involved in the protection of the brain of hypoxic preconditioned mice. Copyright 2005 S. Karger AG, Basel

Constitutive Overexpression of Human Erythropoietin Protects the Mouse Retina against Induced But Not Inherited Retinal Degeneration

PubMed Central

Grimm, Christian; Wenzel, Andreas; Stanescu, Dinu; Samardzija, Marijana; Hotop, Svenja; Groszer, Mathias; Naash, Muna; Gassmann, Max; Remé, Charlotte

2010-01-01

Elevation of erythropoietin (Epo) concentrations by hypoxic preconditioning or application of recombinant human Epo (huEpo) protects the mouse retina against light-induced degeneration by inhibiting photoreceptor cell apoptosis. Because photoreceptor apoptosis is also the common path to cell loss in retinal dystrophies such as retinitis pigmentosa (RP), we tested whether high levels of huEpo would reduce apoptotic cell death in two mouse models of human RP. We combined the two respective mutant mouse lines with a transgenic line (tg6) that constitutively overexpresses huEpo mainly in neural tissues. Transgenic expression of huEpo caused constitutively high levels of Epo in the retina and protected photoreceptors against light-induced degeneration; however, the presence of high levels of huEpo did not affect the course or the extent of retinal degeneration in a light-independent (rd1) and a light-accelerated (VPP) mouse model of RP. Similarly, repetitive intraperitoneal injections of recombinant huEpo did not protect the retina in the rd1 and the VPP mouse. Lack of neuroprotection by Epo in the two models of inherited retinal degeneration was not caused by adaptational downregulation of Epo receptor. Our results suggest that apoptotic mechanisms during acute, light-induced photoreceptor cell death differ from those in genetically based retinal degeneration. Therapeutic intervention with cell death in inherited retinal degeneration may therefore require different drugs and treatments. PMID:15215287

Stable expression of HIF-1α in tubular epithelial cells promotes interstitial fibrosis

PubMed Central

Kimura, Kuniko; Iwano, Masayuki; Higgins, Debra F.; Yamaguchi, Yukinari; Nakatani, Kimihiko; Harada, Koji; Kubo, Atsushi; Akai, Yasuhiro; Rankin, Erinn B.; Neilson, Eric G.; Haase, Volker H.; Saito, Yoshihiko

2008-01-01

Chronic hypoxia accelerates renal fibrosis. The chief mediator of the hypoxic response is hypoxia-inducible factor 1 (HIF-1) and its oxygen-sensitive component HIF-1α. HIF-1 regulates a wide variety of genes, some of which are closely associated with tissue fibrosis. To determine the specific role of HIF-1 in renal fibrosis, we generated a knockout mouse in which tubular epithelial expression of von Hippel-Lindau tumor suppressor (VHL), which acts as a ubiquitin ligase to promote proteolysis of HIF-1α, was targeted. We investigated the effect of VHL deletion (i.e., stable expression of HIF-1α) histologically and used the anti-HIF-1α agent [3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole] (YC-1) to test whether inhibition of HIF-1α could represent a novel approach to treating renal fibrosis. The area of renal fibrosis was significantly increased in a 5/6 renal ablation model of VHL−/− mice and in all VHL−/− mice at least 60 wk of age. Injection of YC-1 inhibited the progression of renal fibrosis in unilateral ureteral obstruction model mice. In conclusion, HIF-1α appears to be a critical contributor to the progression of renal fibrosis and could be a useful target for its treatment. PMID:18667485

Neurological Effects of Exposure to Non-Hypoxic Hypobaria

DTIC Science & Technology

2014-04-16

be at risk for subclinical brain injury, raising concern about the long-term impact in aircrew. Altitude chamber personnel are a second...flight surgeon FSL BET brain extraction tool FSL FLIRT FMRIB’s linear image registration tool IQ intelligence quotient IRB Institutional Review...population would potentially have similar risks and findings. Chronic brain injury in other neurological diseases is associated with lower

Gab1 Is Modulated by Chronic Hypoxia in Children with Cyanotic Congenital Heart Defect and Its Overexpression Reduces Apoptosis in Rat Neonatal Cardiomyocytes

PubMed Central

Cherif, Myriam; Nakaoka, Yoshikazu; Angelini, Gianni D.; Ghorbel, Mohamed T.

2015-01-01

Gab1 (Grb2 associated binding protein 1) is a member of the scaffolding/docking proteins (Gab1, Gab2, and Gab3). It is required for fibroblast cell survival and maintaining cardiac function. Very little is known about human Gab1 expression in response to chronic hypoxia. The present study examined the hypothesis that hypoxia regulates Gab1 expression in human paediatric myocardium and cultured rat cardiomyocytes. Here we showed that Gab1 is expressed in myocardial tissue in acyanotic and cyanotic children with congenital heart defects. Gab1 protein was upregulated in cyanotic compared to acyanotic hearts suggesting that Gab1 upregulation is a component of the survival program initiated by hypoxia in cyanotic children. The expression of other Gab1 interacting partners was not affected by hypoxia and Gab1 regulation. Additionally, using an in vitro model, we demonstrated that overexpressing Gab1 in neonatal cardiomyocytes, under hypoxic condition, resulted in the reduction of apoptosis suggesting a role for this protein in cardiomyocyte survival. Altogether, our data provide strong evidence that Gab1 is important for heart cell survival following hypoxic stress. PMID:26090437

Superoxide Dismutase Mimetic, MnTE-2-PyP, Attenuates Chronic Hypoxia-Induced Pulmonary Hypertension, Pulmonary Vascular Remodeling, and Activation of the NALP3 Inflammasome

PubMed Central

Villegas, Leah R.; Kluck, Dylan; Field, Carlie; Oberley-Deegan, Rebecca E.; Woods, Crystal; Yeager, Michael E.; El Kasmi, Karim C.; Savani, Rashmin C.; Bowler, Russell P.

2013-01-01

Abstract Aims: Pulmonary hypertension (PH) is characterized by an oxidant/antioxidant imbalance that promotes abnormal vascular responses. Reactive oxygen species, such as superoxide (O2•−), contribute to the pathogenesis of PH and vascular responses, including vascular remodeling and inflammation. This study sought to investigate the protective role of a pharmacological catalytic antioxidant, a superoxide dismutase (SOD) mimetic (MnTE-2-PyP), in hypoxia-induced PH, vascular remodeling, and NALP3 (NACHT, LRR, and PYD domain-containing protein 3)–mediated inflammation. Results: Mice (C57/BL6) were exposed to hypobaric hypoxic conditions, while subcutaneous injections of MnTE-2-PyP (5 mg/kg) or phosphate-buffered saline (PBS) were given 3× weekly for up to 35 days. SOD mimetic-treated groups demonstrated protection against increased right ventricular systolic pressure, indirect measurements of pulmonary artery pressure, and RV hypertrophy. Vascular remodeling was assessed by Ki67 staining to detect vascular cell proliferation, α-smooth muscle actin staining to analyze small vessel muscularization, and hyaluronan (HA) measurements to assess extracellular matrix modulation. Activation of the NALP3 inflammasome pathway was measured by NALP3 expression, caspase-1 activation, and interleukin 1-beta (IL-1β) and IL-18 production. Hypoxic exposure increased PH, vascular remodeling, and NALP3 inflammasome activation in PBS-treated mice, while mice treated with MnTE-2-PyP showed an attenuation in each of these endpoints. Innovation: This study is the first to demonstrate activation of the NALP3 inflammasome with cleavage of caspase-1 and release of active IL-1 β and IL-18 in chronic hypoxic PH, as well as its attenuation by the SOD mimetic, MnTE-2-PyP. Conclusion: The ability of the SOD mimetic to scavenge extracellular O2•− supports our previous observations in EC-SOD-overexpressing mice that implicate extracellular oxidant/antioxidant imbalance in hypoxic PH and implicates its role in hypoxia-induced inflammation. Antioxid. Redox Signal. 18, 1753–1764. PMID:23240585

Brain stem NO modulates ventilatory acclimatization to hypoxia in mice.

PubMed

El Hasnaoui-Saadani, R; Alayza, R Cardenas; Launay, T; Pichon, A; Quidu, P; Beaudry, M; Léon-Velarde, F; Richalet, J P; Duvallet, A; Favret, F

2007-11-01

The objective of our study was to assess the role of neuronal nitric oxide synthase (nNOS) in the ventilatory acclimatization to hypoxia. We measured the ventilation in acclimatized Bl6/CBA mice breathing 21% and 8% oxygen, used a nNOS inhibitor, and assessed the expression of N-methyl-d-aspartate (NMDA) glutamate receptor and nNOS (mRNA and protein). Two groups of Bl6/CBA mice (n = 60) were exposed during 2 wk either to hypoxia [barometric pressure (PB) = 420 mmHg] or normoxia (PB = 760 mmHg). At the end of exposure the medulla was removed to measure the concentration of nitric oxide (NO) metabolites, the expression of NMDA-NR1 receptor, and nNOS by real-time RT-PCR and Western blot. We also measured the ventilatory response [fraction of inspired O(2) (Fi(O(2))) = 0.21 and 0.08] before and after S-methyl-l-thiocitrulline treatment (SMTC, nNOS inhibitor, 10 mg/kg ip). Chronic hypoxia caused an increase in ventilation that was reduced after SMTC treatment mainly through a decrease in tidal volume (Vt) in normoxia and in acute hypoxia. However, the difference observed in the magnitude of acute hypoxic ventilatory response [minute ventilation (Ve) 8% - Ve 21%] in acclimatized mice was not different. Acclimatization to hypoxia induced a rise in NMDA receptor as well as in nNOS and NO production. In conclusion, our study provides evidence that activation of nNOS is involved in the ventilatory acclimatization to hypoxia in mice but not in the hypoxic ventilatory response (HVR) while the increased expression of NMDA receptor expression in the medulla of chronically hypoxic mice plays a role in acute HVR. These results are therefore consistent with central nervous system plasticity, partially involved in ventilatory acclimatization to hypoxia through nNOS.

Physiological Responses to Two Hypoxic Conditioning Strategies in Healthy Subjects

PubMed Central

Chacaroun, Samarmar; Borowik, Anna; Morrison, Shawnda A.; Baillieul, Sébastien; Flore, Patrice; Doutreleau, Stéphane; Verges, Samuel

2017-01-01

Objective: Hypoxic exposure can be used as a therapeutic tool by inducing various cardiovascular, neuromuscular, and metabolic adaptations. Hypoxic conditioning strategies have been evaluated in patients with chronic diseases using either sustained (SH) or intermittent (IH) hypoxic sessions. Whether hypoxic conditioning via SH or IH may induce different physiological responses remains to be elucidated. Methods: Fourteen healthy active subjects (7 females, age 25 ± 8 years, body mass index 21.5 ± 2.5 kg·m−2) performed two interventions in a single blind, randomized cross-over design, starting with either 3 x SH (48 h apart), or 3 x IH (48 h apart), separated by a 2 week washout period. SH sessions consisted of breathing a gas mixture with reduced inspiratory oxygen fraction (FiO2), continuously adjusted to reach arterial oxygen saturations (SpO2) of 70–80% for 1 h. IH sessions consisted of 5 min with reduced FiO2 (SpO2 = 70–80%), followed by 3-min normoxia, repeated seven times. During the first (S1) and third (S3) sessions of each hypoxic intervention, cardiorespiratory parameters, and muscle and pre-frontal cortex oxygenation (near infrared spectroscopy) were assessed continuously. Results: Minute ventilation increased significantly during IH sessions (+2 ± 2 L·min−1) while heart rate increased during both SH (+11 ± 4 bpm) and IH (+13 ± 5 bpm) sessions. Arterial blood pressure increased during all hypoxic sessions, although baseline normoxic systolic blood pressure was reduced from S1 to S3 in IH only (−8 ± 11 mmHg). Muscle oxygenation decreased significantly during S3 but not S1, for both hypoxic interventions (S3: SH −6 ± 5%, IH −3 ± 4%); pre-frontal oxygenation decreased in S1 and S3, and to a greater extent in SH vs. IH (−13 ± 3% vs. −6 ± 6%). Heart rate variability indices indicated a significantly larger increase in sympathetic activity in SH vs. IH (lower SDNN, PNN50, and RMSSD values in SH). From S1 to S3, further reduction in heart rate variability was observed in SH (SDNN, PNN50, and RMSSD reduction) while heart rate variability increased in IH (SDNN and RMSSD increase). Conclusions: These results showed significant differences in heart rate variability, blood pressure, and tissue oxygenation changes during short-term SH vs. IH conditioning interventions. Heart rate variability may provide useful information about the early adaptations induced by such intervention. PMID:28119623

Physiological Responses to Two Hypoxic Conditioning Strategies in Healthy Subjects.

PubMed

Chacaroun, Samarmar; Borowik, Anna; Morrison, Shawnda A; Baillieul, Sébastien; Flore, Patrice; Doutreleau, Stéphane; Verges, Samuel

2016-01-01

Objective: Hypoxic exposure can be used as a therapeutic tool by inducing various cardiovascular, neuromuscular, and metabolic adaptations. Hypoxic conditioning strategies have been evaluated in patients with chronic diseases using either sustained (SH) or intermittent (IH) hypoxic sessions. Whether hypoxic conditioning via SH or IH may induce different physiological responses remains to be elucidated. Methods: Fourteen healthy active subjects (7 females, age 25 ± 8 years, body mass index 21.5 ± 2.5 kg·m -2 ) performed two interventions in a single blind, randomized cross-over design, starting with either 3 x SH (48 h apart), or 3 x IH (48 h apart), separated by a 2 week washout period. SH sessions consisted of breathing a gas mixture with reduced inspiratory oxygen fraction (FiO 2 ), continuously adjusted to reach arterial oxygen saturations (SpO 2 ) of 70-80% for 1 h. IH sessions consisted of 5 min with reduced FiO 2 (SpO 2 = 70-80%), followed by 3-min normoxia, repeated seven times. During the first (S1) and third (S3) sessions of each hypoxic intervention, cardiorespiratory parameters, and muscle and pre-frontal cortex oxygenation (near infrared spectroscopy) were assessed continuously. Results : Minute ventilation increased significantly during IH sessions (+2 ± 2 L·min -1 ) while heart rate increased during both SH (+11 ± 4 bpm) and IH (+13 ± 5 bpm) sessions. Arterial blood pressure increased during all hypoxic sessions, although baseline normoxic systolic blood pressure was reduced from S1 to S3 in IH only (-8 ± 11 mmHg). Muscle oxygenation decreased significantly during S3 but not S1, for both hypoxic interventions (S3: SH -6 ± 5%, IH -3 ± 4%); pre-frontal oxygenation decreased in S1 and S3, and to a greater extent in SH vs. IH (-13 ± 3% vs. -6 ± 6%). Heart rate variability indices indicated a significantly larger increase in sympathetic activity in SH vs. IH (lower SDNN, PNN50, and RMSSD values in SH). From S1 to S3, further reduction in heart rate variability was observed in SH (SDNN, PNN50, and RMSSD reduction) while heart rate variability increased in IH (SDNN and RMSSD increase). Conclusions: These results showed significant differences in heart rate variability, blood pressure, and tissue oxygenation changes during short-term SH vs. IH conditioning interventions. Heart rate variability may provide useful information about the early adaptations induced by such intervention.

G protein-coupled receptor 91 signaling in diabetic retinopathy and hypoxic retinal diseases.

PubMed

Hu, Jianyan; Li, Tingting; Du, Xinhua; Wu, Qiang; Le, Yun-Zheng

2017-10-01

G protein-coupled receptor 91 (GPR91) is a succinate-specific receptor and activation of GPR91 could initiate a complex signal transduction cascade and upregulate inflammatory and pro-angiogenic cytokines. In the retina, GPR91 is predominately expressed in ganglion cells, a major cellular entity involved in the pathogenesis of diabetic retinopathy (DR) and other hypoxic retinal diseases. During the development of DR and retinopathy of prematurity (ROP), chronic hypoxia causes an increase in the levels of local succinate. Succinate-mediated GPR91 activation upregulates vascular endothelial growth factor (VEGF) through ERK1/2-C/EBP β (c-Fos) and/or ERK1/2-COX-2/PGE2 signaling pathways, which in turn, leads to the breakdown of blood-retina barriers in these disorders. In this review, we will have a brief introduction of GPR91 and its biological functions and a more detailed discussion about the role and mechanisms of GPR91 in DR and ROP. A better understanding of GPR91 regulation may be of great significance in identifying new biomarkers and drug targets for the prediction and treatment of DR, ROP, and hypoxic retinal diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

The blood antioxidant defence capacity during intermittent hypoxic training in elite swimmers

PubMed Central

Poprzęcki, S; Zając, A; Karpiński, J; Wilk, R; Bril, G; Maszczyk, A; Toborek, M

2016-01-01

The main objective of this study was to examine the chronic effect of simulated intermittent normobaric hypoxia on blood antioxidant defence capacity in swimmers. The study included 14 male and 14 female competitive swimmers performing part of land training under simulated intermittent normobaric hypoxia (O2 = 15.5%) or in normoxia. Land interval training took place twice per week, with a total of 8 training units during the study, performed with individualized intensity. The activities of blood antioxidant enzymes did not change significantly during the first and last training unit in the hypoxic and normoxic group. However, when comparing individual variables a significant effect of exercise was observed on GPx an CAT activities, whereas training units significantly differentiated GPx and GR activities. The oxygen conditions and gender had a significant influence on CAT activity. The total antioxidant capacity was not significantly affected. Only in male swimmers from the hypoxic group did the training significantly increase resting levels of MDA. In conclusion, training in normobaric hypoxia was not an adequate stimulus for the excessive response of the antioxidant defence system, despite increased oxidative stress in these conditions. PMID:28090139

Hypoxia modulates the purine salvage pathway and decreases red blood cell and supernatant levels of hypoxanthine during refrigerated storage.

PubMed

Nemkov, Travis; Sun, Kaiqi; Reisz, Julie A; Song, Anren; Yoshida, Tatsuro; Dunham, Andrew; Wither, Matthew J; Francis, Richard O; Roach, Robert C; Dzieciatkowska, Monika; Rogers, Stephen C; Doctor, Allan; Kriebardis, Anastasios; Antonelou, Marianna; Papassideri, Issidora; Young, Carolyn T; Thomas, Tiffany A; Hansen, Kirk C; Spitalnik, Steven L; Xia, Yang; Zimring, James C; Hod, Eldad A; D'Alessandro, Angelo

2018-02-01

Hypoxanthine catabolism in vivo is potentially dangerous as it fuels production of urate and, most importantly, hydrogen peroxide. However, it is unclear whether accumulation of intracellular and supernatant hypoxanthine in stored red blood cell units is clinically relevant for transfused recipients. Leukoreduced red blood cells from glucose-6-phosphate dehydrogenase-normal or -deficient human volunteers were stored in AS-3 under normoxic, hyperoxic, or hypoxic conditions (with oxygen saturation ranging from <3% to >95%). Red blood cells from healthy human volunteers were also collected at sea level or after 1-7 days at high altitude (>5000 m). Finally, C57BL/6J mouse red blood cells were incubated in vitro with 13 C 1 -aspartate or 13 C 5 -adenosine under normoxic or hypoxic conditions, with or without deoxycoformycin, a purine deaminase inhibitor. Metabolomics analyses were performed on human and mouse red blood cells stored for up to 42 or 14 days, respectively, and correlated with 24 h post-transfusion red blood cell recovery. Hypoxanthine increased in stored red blood cell units as a function of oxygen levels. Stored red blood cells from human glucose-6-phosphate dehydrogenase-deficient donors had higher levels of deaminated purines. Hypoxia in vitro and in vivo decreased purine oxidation and enhanced purine salvage reactions in human and mouse red blood cells, which was partly explained by decreased adenosine monophosphate deaminase activity. In addition, hypoxanthine levels negatively correlated with post-transfusion red blood cell recovery in mice and - preliminarily albeit significantly - in humans. In conclusion, hypoxanthine is an in vitro metabolic marker of the red blood cell storage lesion that negatively correlates with post-transfusion recovery in vivo Storage-dependent hypoxanthine accumulation is ameliorated by hypoxia-induced decreases in purine deamination reaction rates. Copyright© 2018 Ferrata Storti Foundation.

On the pivotal role of PPARα in adaptation of the heart to hypoxia and why fat in the diet increases hypoxic injury

PubMed Central

Cole, Mark A.; Abd Jamil, Amira H.; Heather, Lisa C.; Murray, Andrew J.; Sutton, Elizabeth R.; Slingo, Mary; Sebag-Montefiore, Liam; Tan, Suat Cheng; Aksentijević, Dunja; Gildea, Ottilie S.; Stuckey, Daniel J.; Yeoh, Kar Kheng; Carr, Carolyn A.; Evans, Rhys D.; Aasum, Ellen; Schofield, Christopher J.; Ratcliffe, Peter J.; Neubauer, Stefan; Robbins, Peter A.; Clarke, Kieran

2016-01-01

The role of peroxisome proliferator-activated receptor α (PPARα)-mediated metabolic remodeling in cardiac adaptation to hypoxia has yet to be defined. Here, mice were housed in hypoxia for 3 wk before in vivo contractile function was measured using cine MRI. In isolated, perfused hearts, energetics were measured using 31P magnetic resonance spectroscopy (MRS), and glycolysis and fatty acid oxidation were measured using [3H] labeling. Compared with a normoxic, chow-fed control mouse heart, hypoxia decreased PPARα expression, fatty acid oxidation, and mitochondrial uncoupling protein 3 (UCP3) levels, while increasing glycolysis, all of which served to maintain normal ATP concentrations ([ATP]) and thereby, ejection fractions. A high-fat diet increased cardiac PPARα expression, fatty acid oxidation, and UCP3 levels with decreased glycolysis. Hypoxia was unable to alter the high PPARα expression or reverse the metabolic changes caused by the high-fat diet, with the result that [ATP] and contractile function decreased significantly. The adaptive metabolic changes caused by hypoxia in control mouse hearts were found to have occurred already in PPARα-deficient (PPARα−/−) mouse hearts and sustained function in hypoxia despite an inability for further metabolic remodeling. We conclude that decreased cardiac PPARα expression is essential for adaptive metabolic remodeling in hypoxia, but is prevented by dietary fat.—Cole, M. A., Abd Jamil, A. H., Heather, L. C., Murray, A. J., Sutton, E. R., Slingo, M., Sebag-Montefiore, L., Tan, S. C., Aksentijević, D., Gildea, O. S., Stuckey, D. J., Yeoh, K. K., Carr, C. A., Evans, R. D., Aasum, E., Schofield, C. J., Ratcliffe, P. J., Neubauer, S., Robbins, P. A., Clarke, K. On the pivotal role of PPARα in adaptation of the heart to hypoxia and why fat in the diet increases hypoxic injury. PMID:27103577

Hypoxia modulates the purine salvage pathway and decreases red blood cell and supernatant levels of hypoxanthine during refrigerated storage

PubMed Central

Nemkov, Travis; Sun, Kaiqi; Reisz, Julie A.; Song, Anren; Yoshida, Tatsuro; Dunham, Andrew; Wither, Matthew J.; Francis, Richard O.; Roach, Robert C.; Dzieciatkowska, Monika; Rogers, Stephen C.; Doctor, Allan; Kriebardis, Anastasios; Antonelou, Marianna; Papassideri, Issidora; Young, Carolyn T.; Thomas, Tiffany A.; Hansen, Kirk C.; Spitalnik, Steven L.; Xia, Yang; Zimring, James C.; Hod, Eldad A.; D’Alessandro, Angelo

2018-01-01

Hypoxanthine catabolism in vivo is potentially dangerous as it fuels production of urate and, most importantly, hydrogen peroxide. However, it is unclear whether accumulation of intracellular and supernatant hypoxanthine in stored red blood cell units is clinically relevant for transfused recipients. Leukoreduced red blood cells from glucose-6-phosphate dehydrogenase-normal or -deficient human volunteers were stored in AS-3 under normoxic, hyperoxic, or hypoxic conditions (with oxygen saturation ranging from <3% to >95%). Red blood cells from healthy human volunteers were also collected at sea level or after 1–7 days at high altitude (>5000 m). Finally, C57BL/6J mouse red blood cells were incubated in vitro with 13C1-aspartate or 13C5-adenosine under normoxic or hypoxic conditions, with or without deoxycoformycin, a purine deaminase inhibitor. Metabolomics analyses were performed on human and mouse red blood cells stored for up to 42 or 14 days, respectively, and correlated with 24 h post-transfusion red blood cell recovery. Hypoxanthine increased in stored red blood cell units as a function of oxygen levels. Stored red blood cells from human glucose-6-phosphate dehydrogenase-deficient donors had higher levels of deaminated purines. Hypoxia in vitro and in vivo decreased purine oxidation and enhanced purine salvage reactions in human and mouse red blood cells, which was partly explained by decreased adenosine monophosphate deaminase activity. In addition, hypoxanthine levels negatively correlated with post-transfusion red blood cell recovery in mice and – preliminarily albeit significantly - in humans. In conclusion, hypoxanthine is an in vitro metabolic marker of the red blood cell storage lesion that negatively correlates with post-transfusion recovery in vivo. Storage-dependent hypoxanthine accumulation is ameliorated by hypoxia-induced decreases in purine deamination reaction rates. PMID:29079593

Hypoxia facilitates neurogenic dural plasma protein extravasation in mice: a novel animal model for migraine pathophysiology

PubMed Central

Hunfeld, Anika; Segelcke, Daniel; Bäcker, Ingo; Mecheri, Badreddine; Hemmer, Kathrin; Dlugosch, Elisabeth; Andriske, Michael; Paris, Frank; Zhu, Xinran; Lübbert, Hermann

2015-01-01

Migraine animal models generally mimic the onset of attacks and acute treatment processes. A guinea pig model used the application of meta-chlorophenylpiperazine (mCPP) to trigger immediate dural plasma protein extravasation (PPE) mediated by 5-HT2B receptors. This model has predictive value for antimigraine drugs but cannot explain the delayed onset of efficacy of 5-HT2B receptor antagonists when clinically used for migraine prophylaxis. We found that mCPP failed to induce dural PPE in mice. Considering the role 5-HT2B receptors play in hypoxia-induced pulmonary vessel muscularization, we were encouraged to keep mice under hypoxic conditions and tested whether this treatment will render them susceptible to mCPP-induced dural PPE. Following four-week of hypoxia, PPE, associated with increased transendothelial transport, was induced by mCPP. The effect was blocked by sumatriptan. Chronic application of 5-HT2B receptor or nitric oxide synthase blockers during hypoxia prevented the development of susceptibility. Here we present a migraine model that distinguishes between a migraine-like state (hypoxic mice) and normal, normoxic mice and mimics processes that are related to chronic activation of 5-HT2B receptors under hypoxia. It seems striking, that chronic endogenous activation of 5-HT2B receptors is crucial for the sensitization since 5-HT2B receptor antagonists have strong, albeit delayed migraine prophylactic efficacy. PMID:26644235

Pulmonary blood volume (PRV) in rats with chronic mountain sickness

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

Ou, L.C.; Sardella, G.L.; Hill, N.S.

1986-03-05

Upon chronic exposure to severe hypoxia, Hilltop (H) strain of Sprague-Dawley rats develops excessive polycythemia, severe hypervolemia and marked elevation in pulmonary arterial pressure (PAP), whereas Madison (M) strain develops only moderate responses. Hypervolemia is expected to increase the PBV which might contribute to the development of severe pulmonary hypertension. Two groups of 6 animals each of the H and M strains were exposed to sea level (SL) and a simulated altitude of 18,000 ft for 14 days. At the end of exposure each animal was measured for RBC volume (RBCV), total blood volume (TBV), PBV and PAP under normoxiamore » for control and under hypoxia (10% O/sub 2/) for the hypoxic groups. RBCV was determined by /sup 51/Cr-RBC dilution and PBV was trapped by tightening an implanted loose ligature around the ascending aorta and PA. There were not strain differences in all parameters studied at SL. RBCV, TBV and PAP increased with hypoxia in both strains but significantly more so in H than M. PBV per g lung WT decreased in both strains despite elevated TBV and PAP, but more so in M than H. There were good correlations between the PBV and TBV, and between PAP and PBV in the hypoxic H and M rats. The data suggest that chronic hypoxia reduced the distensibility and perhaps the vascular capacity of the lungs such that small relative increase in PBV could significantly contribute to the rise in PAP.« less

64Cu-CTS: A Promising Radiopharmaceutical for the Identification of Low-Grade Cardiac Hypoxia by PET.

PubMed

Medina, Rodolfo A; Mariotti, Erika; Pavlovic, Davor; Shaw, Karen P; Eykyn, Thomas R; Blower, Philip J; Southworth, Richard

2015-06-01

The subtle hypoxia underlying chronic cardiovascular disease is an attractive target for PET imaging, but the lead hypoxia imaging agents (64)Cu-2,3-butanedione bis(N4-methylthiosemicarbazone) (ATSM) and (18)F-fluoromisonidazole are trapped only at extreme levels of hypoxia and hence are insufficiently sensitive for this purpose. We have therefore sought an analog of (64)Cu-ATSM better suited to identify compromised but salvageable myocardium, and we validated it using parallel biomarkers of cardiac energetics comparable to those observed in chronic cardiac ischemic syndromes. Rat hearts were perfused with aerobic buffer for 20 min, followed by a range of hypoxic buffers (using a computer-controlled gas mixer) for 45 min. Contractility was monitored by intraventricular balloon, energetics by (31)P nuclear MR spectroscopy, lactate and creatine kinase release spectrophotometrically, and hypoxia-inducible factor 1-α by Western blotting. We identified a key hypoxia threshold at a 30% buffer O2 saturation that induces a stable and potentially survivable functional and energetic compromise: left ventricular developed pressure was depressed by 20%, and cardiac phosphocreatine was depleted by 65.5% ± 14% (P < 0.05 vs. control), but adenosine triphosphate levels were maintained. Lactate release was elevated (0.21 ± 0.067 mmol/L/min vs. 0.056 ± 0.01 mmol/L/min, P < 0.05) but not maximal (0.46 ± 0.117 mmol/L/min), indicating residual oxidative metabolic capacity. Hypoxia-inducible factor 1-α was elevated but not maximal. At this key threshold, (64)Cu-2,3-pentanedione bis(thiosemicarbazone) (CTS) selectively deposited significantly more (64)Cu than any other tracer we examined (61.8% ± 9.6% injected dose vs. 29.4% ± 9.5% for (64)Cu-ATSM, P < 0.05). The hypoxic threshold that induced survivable metabolic and functional compromise was 30% O2. At this threshold, only (64)Cu-CTS delivered a hypoxic-to-normoxic contrast of 3:1, and it therefore warrants in vivo evaluation for imaging chronic cardiac ischemic syndromes. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Chronic Hypoxia Inhibits Sex Steroid Hormone-Mediated Attenuation of Ovine Uterine Arterial Myogenic Tone in Pregnancy

PubMed Central

Chang, Katherine; Xiao, DaLiao; Huang, Xiaohui; Xue, Zhice; Yang, Shumei; Longo, Lawrence D.; Zhang, Lubo

2010-01-01

Previous studies in ovine uterine arteries have demonstrated that sex steroid hormones upregulate ERK1/2 expression and downregulate PKC signaling pathway, resulting in the attenuated myogenic tone in pregnancy. The present study tested the hypothesis that chronic hypoxia during gesttation inhibits the sex steroid-mediated adaptation of ERK1/2 and PKC signaling pathways and increases the myogenic tone of uterine arteries. Uterine arteries were isolated from nonpregnant and near-term pregnant sheep that had been maintained at sea level (~300 m) or exposed to high altitude (3,801 m) hypoxia for 110 days. In contrast to the previous findings in normoxic animals, 17β-estradiol and progesterone failed to suppress PKC-induced contractions and the pressure-induced myogenic tone in uterine arteries from hypoxic animals. Western analyses showed that the sex steroids lost their effects on ERK1/2 expression and phospho-ERK1/2 levels, as well as the activation of PKC isozymes in uterine arteries of hypoxic ewes. In normoxic animals, pregnancy and the sex steroid treatments significantly increased uterine artery estrogen receptor α and progesterone receptor B expression. Chronic hypoxia selectively downregulated estrogen receptor α expression in uterine arteries of pregnant animals, and eliminated the upregulation of estrogen receptor α in pregnancy or by the steroid treatments observed in normoxic animals. The results demonstrate that in the ovine uterine artery chronic hypoxia in pregnancy inhibits the sex steroid hormone-mediated adaptation of decreased myogenic tone by downregulating estrogen receptor α expression, providing a mechanism linking hypoxia and maladaptation of uteroplacental circulation, and an increased risk of preeclampsia in pregnancy. PMID:20660818

Wnt-Responsive Cancer Stem Cells Are Located Close to Distorted Blood Vessels and Not in Hypoxic Regions in a p53-Null Mouse Model of Human Breast Cancer

PubMed Central

Landua, John D.; Bu, Wen; Wei, Wei; Li, Fuhai; Wong, Stephen T.C.; Dickinson, Mary E.; Rosen, Jeffrey M.; Lewis, Michael T.

2014-01-01

Cancer stem cells (CSCs, or tumor-initiating cells) may be responsible for tumor formation in many types of cancer, including breast cancer. Using high-resolution imaging techniques, we analyzed the relationship between a Wnt-responsive, CSC-enriched population and the tumor vasculature using p53-null mouse mammary tumors transduced with a lentiviral Wnt signaling reporter. Consistent with their localization in the normal mammary gland, Wnt-responsive cells in tumors were enriched in the basal/myoepithelial population and generally located in close proximity to blood vessels. The Wnt-responsive CSCs did not colocalize with the hypoxia-inducible factor 1α-positive cells in these p53-null basal-like tumors. Average vessel diameter and vessel tortuosity were increased in p53-null mouse tumors, as well as in a human tumor xenograft as compared with the normal mammary gland. The combined strategy of monitoring the fluorescently labeled CSCs and vasculature using high-resolution imaging techniques provides a unique opportunity to study the CSC and its surrounding vasculature. PMID:24797826

In vivo retinal and choroidal hypoxia imaging using a novel activatable hypoxia-selective near-infrared fluorescent probe.

PubMed

Fukuda, Shinichi; Okuda, Kensuke; Kishino, Genichiro; Hoshi, Sujin; Kawano, Itsuki; Fukuda, Masahiro; Yamashita, Toshiharu; Beheregaray, Simone; Nagano, Masumi; Ohneda, Osamu; Nagasawa, Hideko; Oshika, Tetsuro

2016-12-01

Retinal hypoxia plays a crucial role in ocular neovascular diseases, such as diabetic retinopathy, retinopathy of prematurity, and retinal vascular occlusion. Fluorescein angiography is useful for identifying the hypoxia extent by detecting non-perfusion areas or neovascularization, but its ability to detect early stages of hypoxia is limited. Recently, in vivo fluorescent probes for detecting hypoxia have been developed; however, these have not been extensively applied in ophthalmology. We evaluated whether a novel donor-excited photo-induced electron transfer (d-PeT) system based on an activatable hypoxia-selective near-infrared fluorescent (NIRF) probe (GPU-327) responds to both mild and severe hypoxia in various ocular ischemic diseases animal models. The ocular fundus examination offers unique opportunities for direct observation of the retina through the transparent cornea and lens. After injection of GPU-327 in various ocular hypoxic diseases of mouse and rabbit models, NIRF imaging in the ocular fundus can be performed noninvasively and easily by using commercially available fundus cameras. To investigate the safety of GPU-327, electroretinograms were also recorded after GPU-327 and PBS injection. Fluorescence of GPU-327 increased under mild hypoxic conditions in vitro. GPU-327 also yielded excellent signal-to-noise ratio without washing out in vivo experiments. By using near-infrared region, GPU-327 enables imaging of deeper ischemia, such as choroidal circulation. Additionally, from an electroretinogram, GPU-327 did not cause neurotoxicity. GPU-327 identified hypoxic area both in vivo and in vitro.

Mitochondrial Optic Atrophy (OPA) 1 Processing Is Altered in Response to Neonatal Hypoxic-Ischemic Brain Injury

PubMed Central

Baburamani, Ana A.; Hurling, Chloe; Stolp, Helen; Sobotka, Kristina; Gressens, Pierre; Hagberg, Henrik; Thornton, Claire

2015-01-01

Perturbation of mitochondrial function and subsequent induction of cell death pathways are key hallmarks in neonatal hypoxic-ischemic (HI) injury, both in animal models and in term infants. Mitoprotective therapies therefore offer a new avenue for intervention for the babies who suffer life-long disabilities as a result of birth asphyxia. Here we show that after oxygen-glucose deprivation in primary neurons or in a mouse model of HI, mitochondrial protein homeostasis is altered, manifesting as a change in mitochondrial morphology and functional impairment. Furthermore we find that the mitochondrial fusion and cristae regulatory protein, OPA1, is aberrantly cleaved to shorter forms. OPA1 cleavage is normally regulated by a balanced action of the proteases Yme1L and Oma1. However, in primary neurons or after HI in vivo, protein expression of YmelL is also reduced, whereas no change is observed in Oma1 expression. Our data strongly suggest that alterations in mitochondria-shaping proteins are an early event in the pathogenesis of neonatal HI injury. PMID:26393574

Neuroprotective effects of tanshinone I from Danshen extract in a mouse model of hypoxia-ischemia

PubMed Central

Lee, Jae-Chul; Park, Joon Ha; Park, Ok Kyu; Kim, In Hye; Yan, Bing Chun; Ahn, Ji Hyeon; Kwon, Seung-Hae; Choi, Jung Hoon

2013-01-01

Hypoxia-ischemia leads to serious neuronal damage in some brain regions and is a strong risk factor for stroke. The aim of this study was to investigate the neuroprotective effect of tanshinone I (TsI) derived from Danshen (Radix Salvia miltiorrhiza root extract) against neuronal damage using a mouse model of cerebral hypoxia-ischemia. Brain infarction and neuronal damage were examined using 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin and eosin histochemistry, and Fluoro-Jade B histofluorescence. Pre-treatment with TsI (10 mg/kg) was associated with a significant reduction in infarct volume 1 day after hypoxia-ischemia was induced. In addition, TsI protected against hypoxia-ischemia-induced neuronal death in the ipsilateral region. Our present findings suggest that TsI has strong potential for neuroprotection against hypoxic-ischemic damage. These results may be used in research into new anti-stroke medications. PMID:24179693

Neuroprotective properties of melatonin in a model of birth asphyxia in the spiny mouse (Acomys cahirinus).

PubMed

Hutton, Lisa C; Abbass, Mahila; Dickinson, Hayley; Ireland, Zoe; Walker, David W

2009-01-01

Birth asphyxia is associated with disturbed development of the neonatal brain. In this study, we determined if low-dose melatonin (0.1 mg/kg/day), administered to the mother over 7 days at the end of pregnancy, could protect against the effects of birth asphyxia in a precocial species - the spiny mouse (Acomys cahirinus). At 37 days of gestation (term is 38-39 days), pups were subjected to birth asphyxia (7.5 min uterine ischemia) and compared to Cesarean section-delivered controls. At 24 h of age, birth asphyxia had increased markers of CNS inflammation (microglia, macrophage infiltration) and apoptosis (activated caspase-3, fractin) in cortical gray matter, which were reduced to control levels by prior maternal melatonin treatment. Melatonin may be an effective prophylactic agent for use in late pregnancy to protect against hypoxic-ischemic brain injury at birth. (c) 2009 S. Karger AG, Basel.

Tumors exposed to acute cyclic hypoxic stress show enhanced angiogenesis, perfusion and metastatic dissemination.

PubMed

Rofstad, Einar K; Gaustad, Jon-Vidar; Egeland, Tormod A M; Mathiesen, Berit; Galappathi, Kanthi

2010-10-01

Clinical studies have shown that patients with highly hypoxic primary tumors may have poor disease-free and overall survival rates. Studies of experimental tumors have revealed that acutely hypoxic cells may be more metastatic than normoxic or chronically hypoxic cells. In the present work, causal relations between acute cyclic hypoxia and metastasis were studied by periodically exposing BALB/c nu/nu mice bearing A-07 human melanoma xenografts to a low oxygen atmosphere. The hypoxia treatment consisted of 12 cycles of 10 min of 8% O(2) in N(2) followed by 10 min of air for a total of 4 hr, began on the first day after tumor cell inoculation and was given daily until the tumors reached a volume of 100 mm(3). Twenty-four hours after the last hypoxia exposure, the primary tumors were subjected to dynamic contrast-enhanced magnetic resonance imaging for assessment of blood perfusion before being resected and processed for immunohistochemical examinations of microvascular density and expression of proangiogenic factors. Mice exposed to acute cyclic hypoxia showed increased incidence of pulmonary metastases, and the primary tumors of these mice showed increased blood perfusion, microvascular density and vascular endothelial growth factor-A (VEGF-A) expression; whereas, the expression of interleukin-8, platelet-derived endothelial cell growth factor and basic fibroblast growth factor was unchanged. The increased pulmonary metastasis was most likely a consequence of hypoxia-induced VEGF-A upregulation, which resulted in increased angiogenic activity and blood perfusion in the primary tumor and thus facilitated tumor cell intravasation and hematogenous transport into the general circulation.

The common parasite Toxoplasma gondii induces prostatic inflammation and microglandular hyperplasia in a mouse model.

PubMed

Colinot, Darrelle L; Garbuz, Tamila; Bosland, Maarten C; Wang, Liang; Rice, Susan E; Sullivan, William J; Arrizabalaga, Gustavo; Jerde, Travis J

2017-07-01

Inflammation is the most prevalent and widespread histological finding in the human prostate, and associates with the development and progression of benign prostatic hyperplasia and prostate cancer. Several factors have been hypothesized to cause inflammation, yet the role each may play in the etiology of prostatic inflammation remains unclear. This study examined the possibility that the common protozoan parasite Toxoplasma gondii induces prostatic inflammation and reactive hyperplasia in a mouse model. Male mice were infected systemically with T. gondii parasites and prostatic inflammation was scored based on severity and focality of infiltrating leukocytes and epithelial hyperplasia. We characterized inflammatory cells with flow cytometry and the resulting epithelial proliferation with bromodeoxyuridine (BrdU) incorporation. We found that T. gondii infects the mouse prostate within the first 14 days of infection and can establish parasite cysts that persist for at least 60 days. T. gondii infection induces a substantial and chronic inflammatory reaction in the mouse prostate characterized by monocytic and lymphocytic inflammatory infiltrate. T. gondii-induced inflammation results in reactive hyperplasia, involving basal and luminal epithelial proliferation, and the exhibition of proliferative inflammatory microglandular hyperplasia in inflamed mouse prostates. This study identifies the common parasite T. gondii as a new trigger of prostatic inflammation, which we used to develop a novel mouse model of prostatic inflammation. This is the first report that T. gondii chronically encysts and induces chronic inflammation within the prostate of any species. Furthermore, T. gondii-induced prostatic inflammation persists and progresses without genetic manipulation in mice, offering a powerful new mouse model for the study of chronic prostatic inflammation and microglandular hyperplasia. © 2017 Wiley Periodicals, Inc.

Effects of turpentine-induced inflammation on the hypoxic stimulation of intestinal Fe3+ absorption in mice.

PubMed Central

Raja, K. B.; Duane, P.; Peters, T. J.

1990-01-01

Chronic subcutaneous turpentine administration (weekly for 6 weeks) induced a mild normocytic anaemia in mice. In-vitro and in-vivo intestinal Fe3+ absorption parameters were, however, not significantly altered from values in saline-treated or untreated mice. Normal mice, when exposed to 3 days hypoxia demonstrated a 2-3-fold increase in iron absorption in vivo, mainly due to changes in the amount of iron transferred from the mucosa to the plasma and thence to the carcass. A 2-3-fold increase in Vmax was also observed in in-vitro uptake experiments using isolated duodenal fragments. In contrast, turpentine-treated animals, though demonstrating an enhanced in-vitro maximal uptake capacity, failed to elicit an adaptive response in vivo following hypoxic exposure. These findings suggest that a circulating (humoral) factor may be responsible for the inhibition in absorption in vivo in this turpentine-induced inflammatory model. PMID:2278822

[Redox-potential of blood and consistence of energoproviding defence system in cytomegalovirus infection in pregnancy].

PubMed

Dzhikiia, I V; Rizhvadze, M A; Dzhangidze, M A

2006-05-01

We have studied the relationship between the hypoxic change and mitochondrial redox-potential disturbances in the mechanism of pheto-placental insufficiency in pregnancy with cytomegalovirus infection (CMV), detected by the positive anti-CMV-IgG titer and more then 4-fold increase of low avid anti-CMV-IgG. It was shown, that chronic CMV infection induces production of active forms of oxygen, peroxidation of structures and concurrently damage of mitochondria with essential decrease of ATP level. Results of the study have shown the important diagnostic value of estimation of hypoxic-oxidative damage induced by CMV infection. The results also revealed important relationships between the activity of the CMV infection and intensity of mitochondrial damage. On the basis of our investigations we suggest the additional diagnostic test (the determination of citozol NADH dependent isocitratdehydrogenaze activity) to evaluate the depth of CMV induced metabolic disturbances.

Hypoxic Conditioned Medium From Human Adipose-Derived Stem Cells Promotes Mouse Liver Regeneration Through JAK/STAT3 Signaling

PubMed Central

Lee, Sang Chul; Jeong, Hye Jin; Lee, Sang Kuon

2016-01-01

Adipose-derived stem cells (ASCs) mainly exert their function by secreting materials that are collectively termed the secretome. Despite recent attention to the secretome as an alternative to stem cell therapy, the culture conditions for generating optimal secretome contents have not been determined. Therefore, we investigated the role of hypoxic-conditioned media (HCM) from ASCs. Normoxic-conditioned media (NCM) and HCM were obtained after culturing ASCs in 20% O2 or 1% O2 for 24 hours, respectively. Subsequently, partially hepatectomized mice were infused with saline, control medium, NCM, or HCM, and then sera and liver specimens were obtained for analyses. Hypoxia (1% O2) significantly increased mRNA expression of mediators from ASCs, including interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF). HCM infusion significantly increased the number of Ki67-positive cells in the liver (p < .05). HCM infusion significantly increased phospho-signal transducer and activator of transcription 3 (STAT3) and decreased suppressor of cytokine signaling 3 (SOCS3) expression in the liver (p < .05). To determine the role of IL-6 in liver regeneration, we then performed IL-6 RNA interference study. Conditioned media (CM) obtained from ASCs, which were transfected with either siIL-6 or siControl, were administered to partially hepatectomized mice. The siIL-6 CM groups exhibited lower liver proliferation (Ki67-positive cells) and markers of regeneration (protein expression of proliferating cell nuclear antigen, p-STAT3, HGF, and VEGF and liver weights) than the siControl CM groups (p < .05). Taken together, hypoxic preconditioning of ASCs increased expression of mediators promoting anti-inflammatory and regenerative responses. The liver regenerative effects of HCM appear to be mediated by persistent and uninhibited expression of STAT3 in the liver, which results from decreased expression of SOCS3. Significance In this study, it was found that treatment with the medium from hypoxic-preconditioned adipose-derived stem cells (ASCs) increased the viability of hepatotoxic hepatocytes and enhance liver regeneration in partially hepatectomized mice. In addition, the researchers first revealed that the hepatoprotective effects of hypoxic-conditioned media are mediated by persistent and uninhibited expression of signal transducer and activator of transcription 3 in the liver, which result from a decreased expression of suppressor of cytokine signaling 3. Therefore, the hypoxic preconditioning of ASCs is expected to play a crucial role in regenerative medicine by optimizing the production of a highly effective secretome from ASCs. PMID:27102647

Grape seed procyanidin extract attenuates hypoxic pulmonary hypertension by inhibiting oxidative stress and pulmonary arterial smooth muscle cells proliferation.

PubMed

Jin, Haifeng; Liu, Mingcheng; Zhang, Xin; Pan, Jinjin; Han, Jinzhen; Wang, Yudong; Lei, Haixin; Ding, Yanchun; Yuan, Yuhui

2016-10-01

Hypoxia-induced oxidative stress and excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) play important roles in the pathological process of hypoxic pulmonary hypertension (HPH). Grape seed procyanidin extract (GSPE) possesses antioxidant properties and has beneficial effects on the cardiovascular system. However, the effect of GSPE on HPH remains unclear. In this study, adult Sprague-Dawley rats were exposed to intermittent chronic hypoxia for 4 weeks to mimic a severe HPH condition. Hemodynamic and pulmonary pathomorphology data showed that chronic hypoxia significantly increased right ventricular systolic pressures (RVSP), weight of the right ventricle/left ventricle plus septum (RV/LV+S) ratio and median width of pulmonary arteries. GSPE attenuated the elevation of RVSP, RV/LV+S, and reduced the pulmonary vascular structure remodeling. GSPE also increased the levels of SOD and reduced the levels of MDA in hypoxia-induced HPH model. In addition, GSPE suppressed Nox4 mRNA levels, ROS production and PASMCs proliferation. Meanwhile, increased expression of phospho-STAT3, cyclin D1, cyclin D3 and Ki67 in PASMCs caused by hypoxia was down-regulated by GSPE. These results suggested that GSPE might potentially prevent HPH via antioxidant and antiproliferative mechanisms. Copyright © 2016. Published by Elsevier Inc.

Computer mouse use predicts acute pain but not prolonged or chronic pain in the neck and shoulder.

PubMed

Andersen, J H; Harhoff, M; Grimstrup, S; Vilstrup, I; Lassen, C F; Brandt, L P A; Kryger, A I; Overgaard, E; Hansen, K D; Mikkelsen, S

2008-02-01

Computer use may have an adverse effect on musculoskeletal outcomes. This study assessed the risk of neck and shoulder pain associated with objectively recorded professional computer use. A computer programme was used to collect data on mouse and keyboard usage and weekly reports of neck and shoulder pain among 2146 technical assistants. Questionnaires were also completed at baseline and at 12 months. The three outcome measures were: (1) acute pain (measured as weekly pain); (2) prolonged pain (no or minor pain in the neck and shoulder region over four consecutive weeks followed by three consecutive weeks with a high pain score); and (3) chronic pain (reported pain or discomfort lasting more than 30 days and "quite a lot of trouble" during the past 12 months). Risk for acute neck pain and shoulder pain increased linearly by 4% and 10%, respectively, for each quartile increase in weekly mouse usage time. Mouse and keyboard usage time did not predict the onset of prolonged or chronic pain in the neck or shoulder. Women had higher risks for neck and shoulder pain. Number of keystrokes and mouse clicks, length of the average activity period, and micro-pauses did not influence reports of acute or prolonged pain. A few psychosocial factors predicted the risk of prolonged pain. Most computer workers have no or minor neck and shoulder pain, few experience prolonged pain, and even fewer, chronic neck and shoulder pain. Moreover, there seems to be no relationship between computer use and prolonged and chronic neck and shoulder pain.

Reperfusion injury intensifies the adaptive human T cell alloresponse in a human-mouse chimeric artery model.

PubMed

Yi, Tai; Fogal, Birgit; Hao, Zhengrong; Tobiasova, Zuzana; Wang, Chen; Rao, Deepak A; Al-Lamki, Rafia S; Kirkiles-Smith, Nancy C; Kulkarni, Sanjay; Bradley, John R; Bothwell, Alfred L M; Sessa, William C; Tellides, George; Pober, Jordan S

2012-02-01

Perioperative nonimmune injuries to an allograft can decrease graft survival. We have developed a model for studying this process using human materials. Human artery segments were transplanted as infrarenal aortic interposition grafts into an immunodeficient mouse host, allowed to "heal in" for 30 days, and then retransplanted into a second mouse host. To induce a reperfusion injury, the healed-in artery segments were incubated for 3 hours under hypoxic conditions ex vivo before retransplantation. To induce immunologic rejection, the animals receiving the retransplanted artery segment were adoptively transferred with human peripheral blood mononuclear cells or purified T cells from a donor allogeneic to the artery 1 week before surgery. To compare rejection of injured versus healthy tissues, these manipulations were combined. Results were analyzed ex vivo by histology, morphometry, immunohistochemistry, and mRNA quantitation or in vivo by ultrasound. Our results showed that reperfusion injury, which otherwise heals with minimal sequelae, intensifies the degree of allogeneic T cell-mediated injury to human artery segments. We developed a new human-mouse chimeric model demonstrating interactions of reperfusion injury and alloimmunity using human cells and tissues that may be adapted to study other forms of nonimmune injury and other types of adaptive immune responses.

Magnolol suppresses hypoxia-induced angiogenesis via inhibition of HIF-1α/VEGF signaling pathway in human bladder cancer cells.

PubMed

Chen, Meng-Chuan; Lee, Chi-Feng; Huang, Wen-Hsin; Chou, Tz-Chong

2013-05-01

The hypoxic environment in tumors is an important factor causing tumor angiogenesis by activating the key transcription factor, hypoxia-inducible factors-1α (HIF-1α). Magnolol isolated from Magnolia officinalis has been reported to exhibit an anticancer activity via elevation of apoptosis. However, whether magnolol inhibits tumor angiogenesis remains unknown. In the present study, we demonstrated that magnolol significantly inhibited angiogenesis in vitro and in vivo evidenced by the attenuation of hypoxia and vascular endothelial growth factor (VEGF)-induced tube formation of human umbilical vascular endothelial cells, vasculature generation in chicken chorioallantoic membrane and Matrigel plug. In hypoxic human bladder cancer cells (T24), treatment with magnolol inhibited hypoxia-stimulated H2O2 formation, HIF-1α induction including mRNA, protein expression, and transcriptional activity as well as VEGF secretion. Additionally, the enhanced degradation of HIF-1α protein via enhancing prolyl hydroxylase activity and the decreased newly-synthesized HIF-1α protein in hypoxic T24 cells may involve the reduction of HIF-1α protein accumulation by magnolol. Interestingly, magnolol also acts as a VEGFR2 antagonist, and subsequently attenuates the down-stream AKT/mTOR/p70S6K/4E-BP-1 kinase activation both in hypoxic T24 cells and tumor tissues. As expected, administration of magnolol greatly attenuated tumor growth, angiogenesis and the protein expression of HIF-1α, VEGF, CD31, a marker of endothelial cells, and carbonic anhydrase IX, an endogenous marker for hypoxia, in the T24 xenograft mouse model. Collectively, these findings strongly indicate that the anti-agngiogenic activity of magnolol is, at least in part, mediated by suppressing HIF-1α/VEGF-dependent pathways, and suggest that magnolol may be a potential drug for human bladder cancer therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

Environmental enrichment increases the GFAP+ stem cell pool and reverses hypoxia-induced cognitive deficits in juvenile mice.

PubMed

Salmaso, Natalina; Silbereis, John; Komitova, Mila; Mitchell, Patrick; Chapman, Katherine; Ment, Laura R; Schwartz, Michael L; Vaccarino, Flora M

2012-06-27

Premature children born with very low birth weight (VLBW) can suffer chronic hypoxic injury as a consequence of abnormal lung development and cardiovascular abnormalities, often leading to grave neurological and behavioral consequences. Emerging evidence suggests that environmental enrichment improves outcome in animal models of adult brain injury and disease; however, little is known about the impact of environmental enrichment following developmental brain injury. Intriguingly, data on socio-demographic factors from longitudinal studies that examined a number of VLBW cohorts suggest that early environment has a substantial impact on neurological and behavioral outcomes. In the current study, we demonstrate that environmental enrichment significantly enhances behavioral and neurobiological recovery from perinatal hypoxic injury. Using a genetic fate-mapping model that allows us to trace the progeny of GFAP+ astroglial cells, we show that hypoxic injury increases the proportion of astroglial cells that attain a neuronal fate. In contrast, environmental enrichment increases the stem cell pool, both through increased stem cell proliferation and stem cell survival. In mice subjected to hypoxia and subsequent enrichment there is an additive effect of both conditions on hippocampal neurogenesis from astroglia, resulting in a robust increase in the number of neurons arising from GFAP+ cells by the time these mice reach full adulthood.

Endothelial microvesicles in hypoxic hypoxia diseases.

PubMed

Deng, Fan; Wang, Shuang; Xu, Riping; Yu, Wenqian; Wang, Xianyu; Zhang, Liangqing

2018-05-29

Hypoxic hypoxia, including abnormally low partial pressure of inhaled oxygen, external respiratory dysfunction-induced respiratory hypoxia and venous blood flow into the arterial blood, is characterized by decreased arterial oxygen partial pressure, resulting in tissue oxygen deficiency. The specific characteristics include reduced arterial oxygen partial pressure and oxygen content. Hypoxic hypoxia diseases (HHDs) have attracted increased attention due to their high morbidity and mortality and mounting evidence showing that hypoxia-induced oxidative stress, coagulation, inflammation and angiogenesis play extremely important roles in the physiological and pathological processes of HHDs-related vascular endothelial injury. Interestingly, endothelial microvesicles (EMVs), which can be induced by hypoxia, hypoxia-induced oxidative stress, coagulation and inflammation in HHDs, have emerged as key mediators of intercellular communication and cellular functions. EMVs shed from activated or apoptotic endothelial cells (ECs) reflect the degree of ECs damage, and elevated EMVs levels are present in several HHDs, including obstructive sleep apnoea syndrome and chronic obstructive pulmonary disease. Furthermore, EMVs have procoagulant, proinflammatory and angiogenic functions that affect the pathological processes of HHDs. This review summarizes the emerging roles of EMVs in the diagnosis, staging, treatment and clinical prognosis of HHDs. © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

A New Mouse Model That Spontaneously Develops Chronic Liver Inflammation and Fibrosis

PubMed Central

Fransén-Pettersson, Nina; Duarte, Nadia; Nilsson, Julia; Lundholm, Marie; Mayans, Sofia; Larefalk, Åsa; Hannibal, Tine D.; Hansen, Lisbeth; Schmidt-Christensen, Anja; Ivars, Fredrik; Cardell, Susanna; Palmqvist, Richard; Rozell, Björn

2016-01-01

Here we characterize a new animal model that spontaneously develops chronic inflammation and fibrosis in multiple organs, the non-obese diabetic inflammation and fibrosis (N-IF) mouse. In the liver, the N-IF mouse displays inflammation and fibrosis particularly evident around portal tracts and central veins and accompanied with evidence of abnormal intrahepatic bile ducts. The extensive cellular infiltration consists mainly of macrophages, granulocytes, particularly eosinophils, and mast cells. This inflammatory syndrome is mediated by a transgenic population of natural killer T cells (NKT) induced in an immunodeficient NOD genetic background. The disease is transferrable to immunodeficient recipients, while polyclonal T cells from unaffected syngeneic donors can inhibit the disease phenotype. Because of the fibrotic component, early on-set, spontaneous nature and reproducibility, this novel mouse model provides a unique tool to gain further insight into the underlying mechanisms mediating transformation of chronic inflammation into fibrosis and to evaluate intervention protocols for treating conditions of fibrotic disorders. PMID:27441847

Peptidylarginine Deiminases as Drug Targets in Neonatal Hypoxic–Ischemic Encephalopathy

PubMed Central

Lange, Sigrun

2016-01-01

Oxygen deprivation and infection are major causes of perinatal brain injury leading to cerebral palsy and other neurological disabilities. The identification of novel key factors mediating white and gray matter damage are crucial to allow better understanding of the specific contribution of different cell types to the injury processes and pathways for clinical intervention. Recent studies in the Rice–Vannucci mouse model of neonatal hypoxic ischemia (HI) have highlighted novel roles for calcium-regulated peptidylarginine deiminases (PADs) and demonstrated neuroprotective effects of pharmacological PAD inhibition following HI and synergistic infection mimicked by lipopolysaccharide stimulation. PMID:26941709

Acid-Sensitive Sheddable PEGylated PLGA Nanoparticles Increase the Delivery of TNF-α siRNA in Chronic Inflammation Sites

PubMed Central

Aldayel, Abdulaziz M; Naguib, Youssef W; O'Mary, Hannah L; Li, Xu; Niu, Mengmeng; Ruwona, Tinashe B; Cui, Zhengrong

2016-01-01

There has been growing interest in utilizing small interfering RNA (siRNA) specific to pro-inflammatory cytokines, such as tumor necrosis factor-α ( TNF-α), in chronic inflammation therapy. However, delivery systems that can increase the distribution of the siRNA in chronic inflammation sites after intravenous administration are needed. Herein we report that innovative functionalization of the surface of siRNA-incorporated poly (lactic-co-glycolic) acid (PLGA) nanoparticles significantly increases the delivery of the siRNA in the chronic inflammation sites in a mouse model. The TNF-α siRNA incorporated PLGA nanoparticles were prepared by the standard double emulsion method, but using stearoyl-hydrazone-polyethylene glycol 2000, a unique acid-sensitive surface active agent, as the emulsifying agent, which renders (i) the nanoparticles PEGylated and (ii) the PEGylation sheddable in low pH environment such as that in chronic inflammation sites. In a mouse model of lipopolysaccharide-induced chronic inflammation, the acid-sensitive sheddable PEGylated PLGA nanoparticles showed significantly higher accumulation or distribution in chronic inflammation sites than PLGA nanoparticles prepared with an acid-insensitive emulsifying agent (i.e., stearoyl-amide-polyethylene glycol 2000) and significantly increased the distribution of the TNF-α siRNA incorporated into the nanoparticles in inflamed mouse foot. PMID:27434685

Effect of chronic undernutrition on body mass and mechanical bone quality under normoxic and altitude hypoxic conditions.

PubMed

Lezon, Christian; Bozzini, Clarisa; Agûero Romero, Alan; Pinto, Patricia; Champin, Graciela; Alippi, Rosa M; Boyer, Patricia; Bozzini, Carlos E

2016-05-01

Both undernutrition and hypoxia exert a negative influence on both growth pattern and bone mechanical properties in developing rats. The present study explored the effects of chronic food restriction on both variables in growing rats exposed to simulated high-altitude hypoxia. Male rats (n 80) aged 28 d were divided into normoxic (Nx) and hypoxic (Hx) groups. Hx rats were exposed to hypobaric air (380 mmHg) in decompression chambers. At T0, Nx and Hx rats were subdivided into four equal subgroups: normoxic control and hypoxic controls, and normoxic growth-restricted and hypoxic growth-restricted received 80 % of the amount of food consumed freely by their respective controls for a 4-week period. Half of these animals were studied at the end of this period (T4). The remaining rats in each group continued under the same environmental conditions, but food was offered ad libitum to explore the type of catch-up growth during 8 weeks. Structural bone properties (strength and stiffness) were evaluated in the right femur midshaft by the mechanical three-point bending test; geometric properties (length, cross-sectional area, cortical mass, bending cross-sectional moment of inertia) and intrinsic properties of the bone tissue (elastic modulus) were measured or derived from appropriate equations. Bone mineralisation was assessed by ash measurement of the left femur. These data indicate that the growth-retarded effects of diminished food intake, induced either by food restriction or hypoxia-related inhibition of appetite, generated the formation of corresponding smaller bones in which subnormal structural and geometric properties were observed. However, they seemed to be appropriate to the body mass of the animals and suggest, therefore, that the bones were not osteopenic. When food restriction was imposed in Hx rats, the combined effects of both variables were additive, inducing a further reduction of bone mass and bone load-carrying capacity. In all cases, the mechanical properties of the mineralised tissue were unaffected. This and the capacity of the treated bones to undergone complete catch-up growth with full restoration of the biomechanical properties suggest that undernutrition, under either Nx or Hx conditions, does not affect bone behaviour because it remains appropriate to its mechanical functions.

Hypoxia: The Force that Drives Chronic Kidney Disease

PubMed Central

Fu, Qiangwei; Colgan, Sean P; Shelley, Carl Simon

2016-01-01

In the United States the prevalence of end-stage renal disease (ESRD) reached epidemic proportions in 2012 with over 600,000 patients being treated. The rates of ESRD among the elderly are disproportionally high. Consequently, as life expectancy increases and the baby-boom generation reaches retirement age, the already heavy burden imposed by ESRD on the US health care system is set to increase dramatically. ESRD represents the terminal stage of chronic kidney disease (CKD). A large body of evidence indicating that CKD is driven by renal tissue hypoxia has led to the development of therapeutic strategies that increase kidney oxygenation and the contention that chronic hypoxia is the final common pathway to end-stage renal failure. Numerous studies have demonstrated that one of the most potent means by which hypoxic conditions within the kidney produce CKD is by inducing a sustained inflammatory attack by infiltrating leukocytes. Indispensable to this attack is the acquisition by leukocytes of an adhesive phenotype. It was thought that this process resulted exclusively from leukocytes responding to cytokines released from ischemic renal endothelium. However, recently it has been demonstrated that leukocytes also become activated independent of the hypoxic response of endothelial cells. It was found that this endothelium-independent mechanism involves leukocytes directly sensing hypoxia and responding by transcriptional induction of the genes that encode the β2-integrin family of adhesion molecules. This induction likely maintains the long-term inflammation by which hypoxia drives the pathogenesis of CKD. Consequently, targeting these transcriptional mechanisms would appear to represent a promising new therapeutic strategy. PMID:26847481

New Nitric Oxide Donor NCX 1443: Therapeutic Effects on Pulmonary Hypertension in the SAD Mouse Model of Sickle Cell Disease.

PubMed

Abid, Shariq; Kebe, Kanny; Houssaïni, Amal; Tomberli, Françoise; Marcos, Elisabeth; Bizard, Emilie; Breau, Marielle; Parpaleix, Aurelien; Tissot, Claire-Marie; Maitre, Bernard; Lipskaia, Larissa; Derumeaux, Genevieve; Bastia, Elena; Mekontso-Dessap, Armand; Adnot, Serge

2018-05-01

Nitric oxide (NO) donors may be useful for treating pulmonary hypertension (PH) complicating sickle cell disease (SCD), as endogenous NO is inactivated by hemoglobin released by intravascular hemolysis. Here, we investigated the effects of the new NO donor NCX1443 on PH in transgenic SAD mice, which exhibit mild SCD without severe hemolytic anemia. In SAD and wild-type (WT) mice, the pulmonary pressure response to acute hypoxia was similar and was abolished by 100 mg/kg NCX1443. The level of PH was also similar in SAD and WT mice exposed to chronic hypoxia (9% O2) alone or with SU5416 and was similarly reduced by daily NCX1443 gavage. Compared with WT mice, SAD mice exhibited higher levels of HO-1, endothelial NO synthase, and PDE5 but similar levels of lung cyclic guanosine monophosphate. Cultured pulmonary artery smooth muscle cells from SAD mice grew faster than those from WT mice and had higher PDE5 protein levels. Combining NCX1443 and a PDE5 inhibitor suppressed the growth rate difference between SAD and WT cells and induced a larger reduction in hypoxic PH severity in SAD than in WT mice. By amplifying endogenous protective mechanisms, NCX1443 in combination with PDE5 inhibition may prove useful for treating PH complicating SCD.

Tg(Th-Cre)FI172Gsat (Th-Cre) defines neurons that are required for full hypercapnic and hypoxic reflexes.

PubMed

Sun, Jenny J; Ray, Russell S

2017-08-15

The catecholaminergic (CA) system has been implicated in many facets of breathing control and offers an important target to better comprehend the underlying etiologies of both developmental and adult respiratory pathophysiologies. Here, we used a noninvasive DREADD-based pharmacogenetic approach to acutely perturb Tg(Th-Cre)FI172Gsat ( Th-Cre )-defined neurons in awake and unrestrained mice in an attempt to characterize CA function in breathing. We report that clozapine-N-oxide (CNO)-DREADD-mediated inhibition of Th-Cre -defined neurons results in blunted ventilatory responses under respiratory challenge. Under a hypercapnic challenge (5% CO 2 /21% O 2 /74% N 2 ), perturbation of Th-Cre neurons results in reduced f R , [Formula: see text] and [Formula: see text] Under a hypoxic challenge (10% O 2 /90% N 2 ), we saw reduced f R , [Formula: see text] and [Formula: see text], in addition to instability in both interbreath interval and tidal volume, resulting in a Cheyne-Stokes-like respiratory pattern. These findings demonstrate the necessity of Th-Cre -defined neurons for the hypercapnic and hypoxic ventilatory responses and breathing stability during hypoxia. However, given the expanded non-CA expression domains of the Tg(Th-Cre)FI172Gsat mouse line found in the brainstem, full phenotypic effect cannot be assigned solely to CA neurons. Nonetheless, this work identifies a key respiratory population that may lead to further insights into the circuitry that maintains respiratory stability in the face of homeostatic challenges. © 2017. Published by The Company of Biologists Ltd.

Fish Ecology and Evolution in the World's Oxygen Minimum Zones and Implications of a Warming Ocean

NASA Astrophysics Data System (ADS)

Gallo, N.; Navarro, E. C.; Yazzie, A. T.; Barry, J. P.; Levin, L. A.

2016-02-01

Predicting how demersal fish communities will respond as hypoxic areas expand with climate change requires an understanding of how existing oxygen gradients influence the abundance, diversity, and trophic ecology of demersal fish communities. A literature review of studies from continental margins with oxygen minimum zones in the Pacific, Atlantic, and Indian Ocean, is combined with new data from research cruises to the Gulf of California and the US West Coast, to examine how hypoxic areas influence the structure and function of demersal fish communities. Oxygen minimum zones (OMZs) are deep-sea environments where organisms experience chronic hypoxic and suboxic conditions and have persisted over much longer timescales than coastal eutrophication-induced hypoxic zones, allowing for the evolution of adaptations to low oxygen conditions. While coastal studies have found that fish are one of the most hypoxia-intolerant groups, representative demersal fish species in the orders Cottiformes, Scorpaeniformes, Pleuronectiformes, Gobiiformes, Perciformes, Lophiiformes, Carcharhiniformes, Ophidiiformes, Myxiniformes, and Gadiformes have evolved to exploit physiologically extreme OMZ environments and are important components of the benthic community. In OMZs, certain fish species are some of the most hypoxia-tolerant members of the megafauna community, present even under extremely low oxygen conditions (< 5 µmol/kg) where most invertebrates are absent, though these communities are typically characterized by single-species dominance. To explore differences in the trophic ecology of these "hypoxia-tolerant" fish communities, stable isotope and gut content analysis are used to compare the Southern California Bight OMZ core fish community to the hypoxia-intolerant upper slope fish community. Results show that fish living in the OMZ core have significantly enriched δ13C and δ15N signatures and feed on different prey items.

The Hypoxic Response Contributes to Altered Gene Expression and Pre-Capillary Pulmonary Hypertension in Patients with Sickle Cell Disease

PubMed Central

Zhang, Xu; Zhang, Wei; Ma, Shwu-Fan; Desai, Ankit A.; Saraf, Santosh; Miasniakova, Galina; Sergueeva, Adelina; Ammosova, Tatiana; Xu, Min; Nekhai, Sergei; Abbasi, Taimur; Casanova, Nancy G.; Steinberg, Martin H.; Baldwin, Clinton T.; Sebastiani, Paola; Prchal, Josef T.; Kittles, Rick; Garcia, Joe G. N.; Machado, Roberto F.; Gordeuk, Victor R.

2014-01-01

Background We postulated that the hypoxic response in sickle cell disease (SCD) contributes to altered gene expression and pulmonary hypertension, a complication associated with early mortality. Methods and Results To identify genes regulated by the hypoxic response and not other effects of chronic anemia, we compared expression variation in peripheral blood mononuclear cells from 13 SCD subjects with hemoglobin SS genotype and 15 Chuvash polycythemia subjects (VHLR200W homozygotes with constitutive up-regulation of hypoxia inducible factors in the absence of anemia or hypoxia). At 5% false discovery rate, 1040 genes exhibited >1.15 fold change in both conditions; 297 were up-regulated and 743 down-regulated including MAPK8 encoding a mitogen-activated protein kinase important for apoptosis, T-cell differentiation and inflammatory responses. Association mapping with a focus on local regulatory polymorphisms in 61 SCD patients identified expression quantitative trait loci (eQTL) for 103 of these hypoxia response genes. In a University of Illinois SCD cohort the A allele of a MAPK8 eQTL, rs10857560, was associated with pre-capillary pulmonary hypertension defined as mean pulmonary artery pressure ≥25 and pulmonary capillary wedge pressure ≤15 mm Hg at right heart catheterization (allele frequency=0.66; OR=13.8, P=0.00036, n=238). This association was confirmed in an independent Walk-PHaSST cohort (allele frequency=0.65; OR=11.3, P=0.0025, n=519). The homozygous AA genotype of rs10857560 was associated with decreased MAPK8 expression and present in all 14 identified pre-capillary pulmonary hypertension cases among the combined 757 patients. Conclusions Our study demonstrates a prominent hypoxic transcription component in SCD and a MAPK8 eQTL associated with pre-capillary pulmonary hypertension. PMID:24515990

Differential contribution of key metabolic substrates and cellular oxygen in HIF signalling

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

Zhdanov, Alexander V., E-mail: a.zhdanov@ucc.ie; Waters, Alicia H.C.; Golubeva, Anna V.

2015-01-01

Changes in availability and utilisation of O{sub 2} and metabolic substrates are common in ischemia and cancer. We examined effects of substrate deprivation on HIF signalling in PC12 cells exposed to different atmospheric O{sub 2}. Upon 2–4 h moderate hypoxia, HIF-α protein levels were dictated by the availability of glutamine and glucose, essential for deep cell deoxygenation and glycolytic ATP flux. Nuclear accumulation of HIF-1α dramatically decreased upon inhibition of glutaminolysis or glutamine deprivation. Elevation of HIF-2α levels was transcription-independent and associated with the activation of Akt and Erk1/2. Upon 2 h anoxia, HIF-2α levels strongly correlated with cellular ATP,more » produced exclusively via glycolysis. Without glucose, HIF signalling was suppressed, giving way to other regulators of cell adaptation to energy crisis, e.g. AMPK. Consequently, viability of cells deprived of O{sub 2} and glucose decreased upon inhibition of AMPK with dorsomorphin. The capacity of cells to accumulate HIF-2α decreased after 24 h glucose deprivation. This effect, associated with increased AMPKα phosphorylation, was sensitive to dorsomorphin. In chronically hypoxic cells, glutamine played no major role in HIF-2α accumulation, which became mainly glucose-dependent. Overall, the availability of O{sub 2} and metabolic substrates intricately regulates HIF signalling by affecting cell oxygenation, ATP levels and pathways involved in production of HIF-α. - Highlights: • Gln and Glc regulate HIF levels in hypoxic cells by maintaining low O{sub 2} and high ATP. • HIF-α levels under anoxia correlate with cellular ATP and critically depend on Glc. • Gln and Glc modulate activity of Akt, Erk and AMPK, regulating HIF production. • HIF signalling is differentially inhibited by prolonged Glc and Gln deprivation. • Unlike Glc, Gln plays no major role in HIF signalling in chronically hypoxic cells.« less

Lack of the Transcription Factor Hypoxia-Inducible Factor 1α (HIF-1α) in Macrophages Accelerates the Necrosis of Mycobacterium avium-Induced Granulomas.

PubMed

Cardoso, Marcos S; Silva, Tânia M; Resende, Mariana; Appelberg, Rui; Borges, Margarida

2015-09-01

The establishment of mycobacterial infection is characterized by the formation of granulomas, which are well-organized aggregates of immune cells, namely, infected macrophages. The granuloma's main function is to constrain and prevent dissemination of the mycobacteria while focusing the immune response to a limited area. In some cases these lesions can grow progressively into large granulomas which can undergo central necrosis, thereby leading to their caseation. Macrophages are the most abundant cells present in the granuloma and are known to adapt under hypoxic conditions in order to avoid cell death. Our laboratory has developed a granuloma necrosis model that mimics the human pathology of Mycobacterium tuberculosis, using C57BL/6 mice infected intravenously with a low dose of a highly virulent strain of Mycobacterium avium. In this work, a mouse strain deleted of the hypoxia inducible factor 1α (HIF-1α) under the Cre-lox system regulated by the lysozyme M gene promoter was used to determine the relevance of HIF-1α in the caseation of granulomas. The genetic ablation of HIF-1α in the myeloid lineage causes the earlier emergence of granuloma necrosis and clearly induces an impairment of the resistance against M. avium infection coincident with the emergence of necrosis. The data provide evidence that granulomas become hypoxic before undergoing necrosis through the analysis of vascularization and quantification of HIF-1α in a necrotizing mouse model. Our results show that interfering with macrophage adaptation to hypoxia, such as through HIF-1α inactivation, accelerates granuloma necrosis. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Embryonic Stem Cell-Derived Mesenchymal Stem Cells (MSCs) Have a Superior Neuroprotective Capacity Over Fetal MSCs in the Hypoxic-Ischemic Mouse Brain.

PubMed

Hawkins, Kate E; Corcelli, Michelangelo; Dowding, Kate; Ranzoni, Anna M; Vlahova, Filipa; Hau, Kwan-Leong; Hunjan, Avina; Peebles, Donald; Gressens, Pierre; Hagberg, Henrik; de Coppi, Paolo; Hristova, Mariya; Guillot, Pascale V

2018-05-01

Human mesenchymal stem cells (MSCs) have huge potential for regenerative medicine. In particular, the use of pluripotent stem cell-derived mesenchymal stem cells (PSC-MSCs) overcomes the hurdle of replicative senescence associated with the in vitro expansion of primary cells and has increased therapeutic benefits in comparison to the use of various adult sources of MSCs in a wide range of animal disease models. On the other hand, fetal MSCs exhibit faster growth kinetics and possess longer telomeres and a wider differentiation potential than adult MSCs. Here, for the first time, we compare the therapeutic potential of PSC-MSCs (ES-MSCs from embryonic stem cells) to fetal MSCs (AF-MSCs from the amniotic fluid), demonstrating that ES-MSCs have a superior neuroprotective potential over AF-MSCs in the mouse brain following hypoxia-ischemia. Further, we demonstrate that nuclear factor (NF)-κB-stimulated interleukin (IL)-13 production contributes to an increased in vitro anti-inflammatory potential of ES-MSC-conditioned medium (CM) over AF-MSC-CM, thus suggesting a potential mechanism for this observation. Moreover, we show that induced pluripotent stem cell-derived MSCs (iMSCs) exhibit many similarities to ES-MSCs, including enhanced NF-κB signaling and IL-13 production in comparison to AF-MSCs. Future studies should assess whether iMSCs also exhibit similar neuroprotective potential to ES-MSCs, thus presenting a potential strategy to overcome the ethical issues associated with the use of embryonic stem cells and providing a potential source of cells for autologous use against neonatal hypoxic-ischemic encephalopathy in humans. Stem Cells Translational Medicine 2018;7:439-449. © 2018 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

The role of glycogen, glucose and lactate in neuronal activity during hypoxia in the hooded seal (Cystophora cristata) brain.

PubMed

Czech-Damal, N U; Geiseler, S J; Hoff, M L M; Schliep, R; Ramirez, J-M; Folkow, L P; Burmester, T

2014-09-05

The brains of diving mammals are repeatedly exposed to hypoxic conditions during diving. Brain neurons of the hooded seal (Cystophora cristata) have been shown to be more hypoxia tolerant than those of mice, but the underlying mechanisms are not clear. Here we investigated the roles of different metabolic substrates for maintenance of neuronal activity and integrity, by comparing the in vitro spontaneous neuronal activity of brain slices from layer V of the visual cortex of hooded seals with those in mice (Mus musculus). Studies were conducted by manipulating the composition of the artificial cerebrospinal fluid (aCSF), containing either 10 mM glucose, or 20 mM lactate, or no external carbohydrate supply (aglycemia). Normoxic, hypoxic and ischemic conditions were applied. The lack of glucose or the application of lactate in the aCSF containing no glucose had little effect on the neuronal activity of seal neurons in either normoxia or hypoxia, while neurons from mice survived in hypoxia only few minutes regardless of the composition of the aCSF. We propose that seal neurons have higher intrinsic energy stores. Indeed, we found about three times higher glycogen stores in the seal brain (∼4.1 ng per μg total protein in the seal cerebrum) than in the mouse brain. Notably, in aCSF containing no glucose, seal neurons can tolerate 20 mM lactate while in mouse neuronal activity vanished after few minutes even in normoxia. This can be considered as an adaptation to long dives, during which lactate accumulates in the blood. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

A radical scavenger edaravone inhibits matrix metalloproteinase-9 upregulation and blood-brain barrier breakdown in a mouse model of prolonged cerebral hypoperfusion

PubMed Central

Maki, Takakuni; Liang, Anna C.; Arai, Ken

2014-01-01

Matrix metalloproteinase-9 (MMP-9) plays key roles in the brain pathophysiology, especially in blood-brain barrier (BBB) breakdown. Therefore, inhibiting MMP-9 activity may be a promising therapy for protecting brains in cerebrovascular diseases. Here we show that in a mouse prolonged cerebral hypoperfusion model, a clinically proven radical scavenger edaravone suppressed MMP-9 and reduced BBB damage in cerebral white matter. Prolonged cerebral hypoperfusion was induced by bilateral common carotid artery stenosis in male adult C57BL/6J mice (10 weeks old). After 7 days of cerebral hypoperfusion, white matter region (e.g. corpus callosum) exhibited significant BBB leakage, assessed by IgG staining. Correspondingly, immunostaining and western blotting showed that MMP-9 was upregulated in the white matter. Edaravone treatment (3 mg/kg, i.p. at day 0 and 3) inhibited both BBB leakage and MMP-9 increase. Under the early phase of cerebral hypoperfusion conditions, oligodendrocyte precursor cells (OPCs) mainly contribute to the MMP-9 increase, but our immunostaining data showed that very little OPCs expressed MMP-9 in the edaravone-treated animals at day 7. Therefore, in vitro studies with primary rat OPCs were conducted to examine whether edaravone would directly suppressed MMP-9 expressions in OPCs. OPC cultures were exposed to sub-lethal CoCl2 for 7 days to induce prolonged chemical hypoxic stress. Prolonged chemical hypoxic stress increased MMP-9 expression in OPCs, and radical scavenging with edaravone (10 μM for 7 days) ameliorated the increase. Taken together, our proof-of-concept study demonstrates that radical scavengers may provide a potential therapeutic approach for white matter injury by suppressing BBB damage. PMID:24820542

A radical scavenger edaravone inhibits matrix metalloproteinase-9 upregulation and blood-brain barrier breakdown in a mouse model of prolonged cerebral hypoperfusion.

PubMed

Miyamoto, Nobukazu; Pham, Loc-Duyen D; Maki, Takakuni; Liang, Anna C; Arai, Ken

2014-06-24

Matrix metalloproteinase-9 (MMP-9) plays key roles in the brain pathophysiology, especially in blood-brain barrier (BBB) breakdown. Therefore, inhibiting MMP-9 activity may be a promising therapy for protecting brains in cerebrovascular diseases. Here we show that in a mouse prolonged cerebral hypoperfusion model, a clinically proven radical scavenger edaravone suppressed MMP-9 and reduced BBB damage in cerebral white matter. Prolonged cerebral hypoperfusion was induced by bilateral common carotid artery stenosis in male adult C57BL/6J mice (10 weeks old). After 7 days of cerebral hypoperfusion, white matter region (e.g. corpus callosum) exhibited significant BBB leakage, assessed by IgG staining. Correspondingly, immunostaining and western blotting showed that MMP-9 was upregulated in the white matter. Edaravone treatment (3mg/kg, i.p. at days 0 and 3) inhibited both BBB leakage and MMP-9 increase. Under the early phase of cerebral hypoperfusion conditions, oligodendrocyte precursor cells (OPCs) mainly contribute to the MMP-9 increase, but our immunostaining data showed that very little OPCs expressed MMP-9 in the edaravone-treated animals at day 7. Therefore, in vitro studies with primary rat OPCs were conducted to examine whether edaravone would directly suppressed MMP-9 expressions in OPCs. OPC cultures were exposed to sub-lethal CoCl2 for 7 days to induce prolonged chemical hypoxic stress. Prolonged chemical hypoxic stress increased MMP-9 expression in OPCs, and radical scavenging with edaravone (10μM for 7 days) ameliorated the increase. Taken together, our proof-of-concept study demonstrates that radical scavengers may provide a potential therapeutic approach for white matter injury by suppressing BBB damage. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Cysteine residues 244 and 458-459 within the catalytic subunit of Na,K-ATPase control the enzyme's hydrolytic and signaling function under hypoxic conditions.

PubMed

Petrushanko, Irina Yu; Mitkevich, Vladimir A; Lakunina, Valentina A; Anashkina, Anastasia A; Spirin, Pavel V; Rubtsov, Peter M; Prassolov, Vladimir S; Bogdanov, Nikolay B; Hänggi, Pascal; Fuller, William; Makarov, Alexander A; Bogdanova, Anna

2017-10-01

Our previous findings suggested that reversible thiol modifications of cysteine residues within the actuator (AD) and nucleotide binding domain (NBD) of the Na,K-ATPase may represent a powerful regulatory mechanism conveying redox- and oxygen-sensitivity of this multifunctional enzyme. S-glutathionylation of Cys244 in the AD and Cys 454-458-459 in the NBD inhibited the enzyme and protected cysteines' thiol groups from irreversible oxidation under hypoxic conditions. In this study mutagenesis approach was used to assess the role these cysteines play in regulation of the Na,K-ATPase hydrolytic and signaling functions. Several constructs of mouse α1 subunit of the Na,K-ATPase were produced in which Cys244, Cys 454-458-459 or Cys 244-454-458-459 were replaced by alanine. These constructs were expressed in human HEK293 cells. Non-transfected cells and those expressing murine α1 subunit were exposed to hypoxia or treated with oxidized glutathione (GSSG). Both conditions induced inhibition of the wild type Na,K-ATPase. Enzymes containing mutated mouse α1 lacking Cys244 or all four cysteines (Cys 244-454-458-459) were insensitive to hypoxia. Inhibitory effect of GSSG was observed for wild type murine Na,K-ATPase, but was less pronounced in Cys454-458-459Ala mutant and completely absent in the Cys244Ala and Cys 244-454-458-459Ala mutants. In cells, expressing wild type enzyme, ouabain induced activation of Src and Erk kinases under normoxic conditions, whereas under hypoxic conditions this effect was inversed. Cys454-458-459Ala substitution abolished Src kinase activation in response to ouabain treatment, uncoupled Src from Erk signaling, and interfered with O 2 -sensitivity of Na,K-ATPase signaling function. Moreover, modeling predicted that S-glutathionylation of Cys 458 and 459 should prevent inhibitory binding of Src to NBD. Our data indicate for the first time that cysteine residues within the AD and NBD influence hydrolytic as well as receptor function of the Na,K-ATPase and alter responses of the enzyme to hypoxia or upon treatment with cardiotonic steroids. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Early Detection of Hypothermic Neuroprotection Using T2-Weighted Magnetic Resonance Imaging in a Mouse Model of Hypoxic Ischemic Encephalopathy.

PubMed

Doman, Sydney E; Girish, Akanksha; Nemeth, Christina L; Drummond, Gabrielle T; Carr, Patrice; Garcia, Maxine S; Johnston, Michael V; Kannan, Sujatha; Fatemi, Ali; Zhang, Jiangyang; Wilson, Mary Ann

2018-01-01

Perinatal hypoxic-ischemic encephalopathy (HIE) can lead to neurodevelopmental disorders, including cerebral palsy. Standard care for neonatal HIE includes therapeutic hypothermia, which provides partial neuroprotection; magnetic resonance imaging (MRI) is often used to assess injury and predict outcome after HIE. Immature rodent models of HIE are used to evaluate mechanisms of injury and to examine the efficacy and mechanisms of neuroprotective interventions such as hypothermia. In this study, we first confirmed that, in the CD1 mouse model of perinatal HIE used for our research, MRI obtained 3 h after hypoxic ischemia (HI) could reliably assess initial brain injury and predict histopathological outcome. Mice were subjected to HI (unilateral carotid ligation followed by exposure to hypoxia) on postnatal day 7 and were imaged with T2-weighted MRI and diffusion-weighted MRI (DWI), 3 h after HI. Clearly defined regions of increased signal were comparable in T2 MRI and DWI, and we found a strong correlation between T2 MRI injury scores 3 h after HI and histopathological brain injury 7 days after HI, validating this method for evaluating initial injury in this model of HIE. The more efficient, higher resolution T2 MRI was used to score initial brain injury in subsequent studies. In mice treated with hypothermia, we found a significant reduction in T2 MRI injury scores 3 h after HI, compared to normothermic littermates. Early hypothermic neuroprotection was maintained 7 days after HI, in both T2 MRI injury scores and histopathology. In the normothermic group, T2 MRI injury scores 3 h after HI were comparable to those obtained 7 days after HI. However, in the hypothermic group, brain injury was significantly less 7 days after HI than at 3 h. Thus, early neuroprotective effects of hypothermia were enhanced by 7 days, which may reflect the additional 3 h of hypothermia after imaging or effects on later mechanisms of injury, such as delayed cell death and inflammation. Our results demonstrate that hypothermia has early neuroprotective effects in this model. These findings suggest that hypothermia has an impact on early mechanisms of excitotoxic injury and support initiation of hypothermic intervention as soon as possible after diagnosis of HIE.

Early Detection of Hypothermic Neuroprotection Using T2-Weighted Magnetic Resonance Imaging in a Mouse Model of Hypoxic Ischemic Encephalopathy

PubMed Central

Doman, Sydney E.; Girish, Akanksha; Nemeth, Christina L.; Drummond, Gabrielle T.; Carr, Patrice; Garcia, Maxine S.; Johnston, Michael V.; Kannan, Sujatha; Fatemi, Ali; Zhang, Jiangyang; Wilson, Mary Ann

2018-01-01

Perinatal hypoxic-ischemic encephalopathy (HIE) can lead to neurodevelopmental disorders, including cerebral palsy. Standard care for neonatal HIE includes therapeutic hypothermia, which provides partial neuroprotection; magnetic resonance imaging (MRI) is often used to assess injury and predict outcome after HIE. Immature rodent models of HIE are used to evaluate mechanisms of injury and to examine the efficacy and mechanisms of neuroprotective interventions such as hypothermia. In this study, we first confirmed that, in the CD1 mouse model of perinatal HIE used for our research, MRI obtained 3 h after hypoxic ischemia (HI) could reliably assess initial brain injury and predict histopathological outcome. Mice were subjected to HI (unilateral carotid ligation followed by exposure to hypoxia) on postnatal day 7 and were imaged with T2-weighted MRI and diffusion-weighted MRI (DWI), 3 h after HI. Clearly defined regions of increased signal were comparable in T2 MRI and DWI, and we found a strong correlation between T2 MRI injury scores 3 h after HI and histopathological brain injury 7 days after HI, validating this method for evaluating initial injury in this model of HIE. The more efficient, higher resolution T2 MRI was used to score initial brain injury in subsequent studies. In mice treated with hypothermia, we found a significant reduction in T2 MRI injury scores 3 h after HI, compared to normothermic littermates. Early hypothermic neuroprotection was maintained 7 days after HI, in both T2 MRI injury scores and histopathology. In the normothermic group, T2 MRI injury scores 3 h after HI were comparable to those obtained 7 days after HI. However, in the hypothermic group, brain injury was significantly less 7 days after HI than at 3 h. Thus, early neuroprotective effects of hypothermia were enhanced by 7 days, which may reflect the additional 3 h of hypothermia after imaging or effects on later mechanisms of injury, such as delayed cell death and inflammation. Our results demonstrate that hypothermia has early neuroprotective effects in this model. These findings suggest that hypothermia has an impact on early mechanisms of excitotoxic injury and support initiation of hypothermic intervention as soon as possible after diagnosis of HIE.

Neuroprotective and Anti-Inflammatory Effects of the Flavonoid-Enriched Fraction AF4 in a Mouse Model of Hypoxic-Ischemic Brain Injury

PubMed Central

Keddy, Paul G. W.; Dunlop, Kate; Warford, Jordan; Samson, Michel L.; Jones, Quinton R. D.; Rupasinghe, H. P. Vasantha; Robertson, George S.

2012-01-01

We report here neuroprotective and anti-inflammatory effects of a flavonoid-enriched fraction isolated from the peel of Northern Spy apples (AF4) in a mouse of model of hypoxic-ischemic (HI) brain damage. Oral administration of AF4 (50 mg/kg, once daily for 3 days) prior to 50 min of HI completely prevented motor performance deficits assessed 14 days later that were associated with marked reductions in neuronal cell loss in the dorsal hippocampus and striatum. Pre-treatment with AF4 (5, 10, 25 or 50 mg/kg, p.o.; once daily for 3 days) produced a dose-dependent reduction in HI-induced hippocampal and striatal neuron cell loss, with 25 mg/kg being the lowest dose that achieved maximal neuroprotection. Comparison of the effects of 1, 3 or 7 doses of AF4 (25 mg/kg; p.o.) prior to HI revealed that at least 3 doses of AF4 were required before HI to reduce neuronal cell loss in both the dorsal hippocampus and striatum. Quantitative RT-PCR measurements revealed that the neuroprotective effects of AF4 (25 mg/kg; p.o.; once daily for 3 days) in the dorsal hippocampus were associated with a suppression of HI-induced increases in the expression of IL-1β, TNF-α and IL-6. AF4 pre-treatment enhanced mRNA levels for pro-survival proteins such as X-linked inhibitor of apoptosis and erythropoietin following HI in the dorsal hippocampus and striatum, respectively. Primary cultures of mouse cortical neurons incubated with AF4 (1 µg/ml), but not the same concentrations of either quercetin or quercetin-3-O-glucose or its metabolites, were resistant to cell death induced by oxygen glucose deprivation. These findings suggest that the inhibition of HI-induced brain injury produced by AF4 likely involves a transcriptional mechanism resulting from the co-operative actions of various phenolics in this fraction which not only reduce the expression of pro-inflammatory mediators but also enhance pro-survival gene signalling. PMID:23251498

The effect of prenatal nicotine on mRNA of central cholinergic markers and hematological parameters in rat fetuses

PubMed Central

Mao, Caiping; Yuan, Xin; Zhang, Hong; Lv, Juanxiu; Guan, Junchang; Miao, Liyan; Chen, Linqi; Zhang, Yuying; Zhang, Lubo; Xu, Zhice

2009-01-01

A number of studies have demonstrated the influence of nicotine on fetal development. This study determined the expression of choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), and high-affinity choline transporter (CHT1) in the forebrain and hindbrain following chronic prenatal nicotine exposure in the rat fetus (maternal rats were subcutaneously injected with nicotine at different gestation periods). We also measured the effect of chronic nicotine exposure on fetal blood pO2, pCO2, pH, Na+ and K+ concentrations, as well as lactic acid levels. Maternal nicotine exposure during pregnancy was associated with a decrease in fetal pO2 coupled with a significant increase in pCO2 and lactic acid as well as restricted fetal growth. Additionally, maternal nicotine administration also reduced ChAT, VAChT, and CHT1 mRNA levels in the fetal brain. Nicotine-induced fetal hypoxic responses and reduced cholinergic marker expression in the brain were more severe when nicotine was started in early gestation. Our results provide new information about the effects of repeated exposure to nicotine in utero on the expression of central ChAT, VAChT, and CHT1 in the rat fetus. These results indicate that repeated hypoxic episodes or/and a direct effect of nicotine on the central cholinergic system during pregnancy may contribute to brain developmental problems in fetal origin. PMID:18407449

TNF-alpha and endotoxin increase hypoxia-induced VEGF production by cultured human nasal fibroblasts in synergistic fashion.

PubMed

Sun, Dong; Matsune, Shoji; Ohori, Junichiro; Fukuiwa, Tatsuya; Ushikai, Masato; Kurono, Yuichi

2005-09-01

Vascular endothelial growth factor (VEGF) promotes angiogenesis and is associated with the invasion and metastasis of malignant tumors. It enhances vascular permeability and is expressed in inflammatory nasal as well as middle-ear mucosa. As the mechanism of VEGF induction during chronic inflammation, such as chronic paranasal sinusitis (CPS) remains to be clarified, we studied the factors regulating the production of VEGF in cultured human nasal fibroblasts and discussed the role of VEGF in the pathogenesis of CPS. We used ELISA to quantify VEGF levels in paranasal sinus effusions, nasal secretions, and serum from patients with CPS. In addition, we cultured human nasal fibroblasts isolated from nasal polyps of CPS patients and studied the effects of hypoxia, TNF-alpha, and endotoxin on their production of VEGF using ELISA and PCR. The VEGF concentration was significantly higher in paranasal sinus effusions than in nasal secretions and serum. Nasal fibroblasts produced high levels of VEGF, when cultured under hypoxic condition and this production was remarkably enhanced in the presence of TNF-alpha or endotoxin. VEGF is locally produced in paranasal sinuses as well as nasal mucosa and its production is increased in patients with CPS. Hypoxia is associated with the production of VEGF by nasal fibroblasts and TNF-alpha and endotoxin may act synergistically to enhance VEGF production in paranasal sinuses under hypoxic condition.

Dietary nitrate and nitrite modulate blood and organ nitrite and the cellular ischemic stress response

PubMed Central

Raat, Nicolaas J.H.; Noguchi, Audrey C.; Liu, Virginia B.; Raghavachari, Nalini; Liu, Delong; Xu, Xiuli; Shiva, Sruti; Munson, Peter J.; Gladwin, Mark T.

2009-01-01

Dietary nitrate, found in abundance in green vegetables, can be converted to the cytoprotective molecule nitrite by oral bacteria, suggesting that nitrate and nitrite may represent active cardioprotective constituents of the Mediterranean diet. We therefore tested the hypothesis that dietary nitrate and nitrite levels modulate tissue damage and ischemic gene expression in a mouse liver ischemia-reperfusion model. We found that stomach content, plasma, heart and liver nitrite levels were significantly reduced after dietary nitrate and nitrite depletion, and could be restored to normal levels with nitrite supplementation in water. Remarkably, we confirmed that basal nitrite levels significantly reduced liver injury after ischemia-reperfusion. Consistent with an effect of nitrite on the post-translational modification of complex I of the mitochondrial electron transport chain, the severity of liver infarction was inversely proportional to complex I activity after nitrite repletion in the diet. The transcriptional response of dietary nitrite after ischemia was more robust than after normoxia, suggesting a hypoxic potentiation of nitrite-dependent transcriptional signaling. Our studies indicate that normal dietary nitrate and nitrite levels modulate ischemic stress responses and hypoxic gene expression programs, supporting the hypothesis that dietary nitrate and nitrite are cytoprotective components of the diet. PMID:19464364

Plasticity of cardiovascular function in snapping turtle embryos (Chelydra serpentina): chronic hypoxia alters autonomic regulation and gene expression.

PubMed

Eme, John; Rhen, Turk; Tate, Kevin B; Gruchalla, Kathryn; Kohl, Zachary F; Slay, Christopher E; Crossley, Dane A

2013-06-01

Reptile embryos tolerate large decreases in the concentration of ambient oxygen. However, we do not fully understand the mechanisms that underlie embryonic cardiovascular short- or long-term responses to hypoxia in most species. We therefore measured cardiac growth and function in snapping turtle embryos incubated under normoxic (N21; 21% O₂) or chronic hypoxic conditions (H10; 10% O₂). We determined heart rate (fH) and mean arterial pressure (Pm) in acute normoxic (21% O₂) and acute hypoxic (10% O₂) conditions, as well as embryonic responses to cholinergic, adrenergic, and ganglionic pharmacological blockade. Compared with N21 embryos, chronic H10 embryos had smaller bodies and relatively larger hearts and were hypotensive, tachycardic, and following autonomic neural blockade showed reduced intrinsic fH at 90% of incubation. Unlike other reptile embryos, cholinergic and ganglionic receptor blockade both increased fH. β-Adrenergic receptor blockade with propranolol decreased fH, and α-adrenergic blockade with phentolamine decreased Pm. We also measured cardiac mRNA expression. Cholinergic tone was reduced in H10 embryos, but cholinergic receptor (Chrm2) mRNA levels were unchanged. However, expression of adrenergic receptor mRNA (Adrb1, Adra1a, Adra2c) and growth factor mRNA (Igf1, Igf2, Igf2r, Pdgfb) was lowered in H10 embryos. Hypoxia altered the balance between cholinergic receptors, α-adrenoreceptor and β-adrenoreceptor function, which was reflected in altered intrinsic fH and adrenergic receptor mRNA levels. This is the first study to link gene expression with morphological and cardioregulatory plasticity in a developing reptile embryo.

Gestational hypoxia induces preeclampsia-like symptoms via heightened endothelin-1 signaling in pregnant rats.

PubMed

Zhou, Jianjun; Xiao, Daliao; Hu, Yali; Wang, Zhiqun; Paradis, Alexandra; Mata-Greenwood, Eugenia; Zhang, Lubo

2013-09-01

Preeclampsia is a life-threatening pregnancy disorder. However, its pathogenesis remains unclear. We tested the hypothesis that gestational hypoxia induces preeclampsia-like symptoms via heightened endothelin-1 (ET-1) signaling. Time-dated pregnant and nonpregnant rats were divided into normoxic and hypoxic (10.5% O2 from the gestational day 6-21) groups. Chronic hypoxia had no significant effect on blood pressure or proteinuria in nonpregnant rats but significantly increased blood pressure on day 12 (systolic blood pressure, 111.7 ± 6.1 versus 138.5 ± 3.5 mm Hg; P=0.004) and day 20 (systolic blood pressure, 103.4 ± 4.6 versus 125.1 ± 6.1 mm Hg; P=0.02) in pregnant rats and urine protein (μg/μL)/creatinine (nmol/μL) ratio on day 20 (0.10 ± 0.01 versus 0.20 ± 0.04; P=0.04), as compared with the normoxic control group. This was accompanied with asymmetrical fetal growth restriction. Hypoxia resulted in impaired trophoblast invasion and uteroplacental vascular remodeling. In addition, plasma ET-1 levels, as well as the abundance of prepro-ET-1 mRNA, ET-1 type A receptor and angiotensin II type 1 receptor protein in the kidney and placenta were significantly increased in the chronic hypoxic group, as compared with the control animals. Treatment with the ET-1 type A receptor antagonist, BQ123, during the course of hypoxia exposure significantly attenuated the hypoxia-induced hypertension and other preeclampsia-like features. The results demonstrate that chronic hypoxia during gestation induces preeclamptic symptoms in pregnant rats via heightened ET-1 and ET-1 type A receptor-mediated signaling, providing a molecular mechanism linking gestational hypoxia and increased risk of preeclampsia.

Activating the Wnt/β-Catenin Pathway Did Not Protect Immature Retina from Hypoxic-Ischemic Injury.

PubMed

Huang, Hsiu-Mei; Huang, Chao-Ching; Wang, Feng-Sheng; Hung, Pi-Liang; Chang, Ying-Chao

2015-07-01

Visual loss associated with hypoxic-ischemic (HI) brain damage is the most common cause of visual impairment in children of developed countries. A neuroprotective role for Wnt/β-catenin signaling has been demonstrated in several neurodegenerative disorders. The association of Wnt signaling with HI injury in immature retina has not been established. On postnatal day 7 (P7), HI was induced by unilateral common carotid artery ligation followed by 8% oxygen hypoxia for 2 hours. The pups received intravitreous injection (i.v.i) of PBS, Dickkopf-1 (DKK-1, the negative modulator of Wnt/β-catenin pathway) antisense (AS) or sense (S) oligonucleotides at various concentrations for pretreatment (24 and 1 hour before HI) or post treatment (1 and 4 hours after HI). For chronic treatments, animals received repeated intraperitoneal (i.p.) injection of DKK-1-AS, DKK-1-S, lithium chloride (LiCl), or vehicles after HI. The retinal injury was assessed by electroretinography (ERG, P21, and P30) and immunohistochemical staining (P8 or P30). Pretreatment with DKK-1-AS (i.v.i.) attenuated DKK-1 and enhanced β-catenin expression, but did not protect immature retina against HI injury at both pathological and functional levels. Post treatment with DKK-1-AS (i.v.i. or i.p.) also did not rescue HI retinopathy. Chronic systemic LiCl treatment did not decrease Müller cell activation or neuronal damage in HI retinal injury. Our data demonstrated that DKK-1 inhibition or chronic lithium treatment did not protect the immature retina from HI injury. It is speculated that the enhanced canonical Wnt/β-catenin signaling is not sufficient to protect the immature retina from HI injury.

Lung Oxidative Damage by Hypoxia

PubMed Central

Araneda, O. F.; Tuesta, M.

2012-01-01

One of the most important functions of lungs is to maintain an adequate oxygenation in the organism. This organ can be affected by hypoxia facing both physiological and pathological situations. Exposure to this condition favors the increase of reactive oxygen species from mitochondria, as from NADPH oxidase, xanthine oxidase/reductase, and nitric oxide synthase enzymes, as well as establishing an inflammatory process. In lungs, hypoxia also modifies the levels of antioxidant substances causing pulmonary oxidative damage. Imbalance of redox state in lungs induced by hypoxia has been suggested as a participant in the changes observed in lung function in the hypoxic context, such as hypoxic vasoconstriction and pulmonary edema, in addition to vascular remodeling and chronic pulmonary hypertension. In this work, experimental evidence that shows the implied mechanisms in pulmonary redox state by hypoxia is reviewed. Herein, studies of cultures of different lung cells and complete isolated lung and tests conducted in vivo in the different forms of hypoxia, conducted in both animal models and humans, are described. PMID:22966417

Inhibition of intracellular lipolysis promotes human cancer cell adaptation to hypoxia

PubMed Central

Zhang, Xiaodong; Saarinen, Alicia M; Hitosugi, Taro; Wang, Zhenghe; Wang, Liguo; Ho, Thai H

2017-01-01

Tumor tissues are chronically exposed to hypoxia owing to aberrant vascularity. Lipid droplet (LD) accumulation is a hallmark of hypoxic cancer cells, yet how LDs form and function during hypoxia remains poorly understood. Herein, we report that in various cancer cells upon oxygen deprivation, HIF-1 activation down-modulates LD catabolism mediated by adipose triglyceride lipase (ATGL), the key enzyme for intracellular lipolysis. Proteomics and functional analyses identified hypoxia-inducible gene 2 (HIG2), a HIF-1 target, as a new inhibitor of ATGL. Knockout of HIG2 enhanced LD breakdown and fatty acid (FA) oxidation, leading to increased ROS production and apoptosis in hypoxic cancer cells as well as impaired growth of tumor xenografts. All of these effects were reversed by co-ablation of ATGL. Thus, by inhibiting ATGL, HIG2 acts downstream of HIF-1 to sequester FAs in LDs away from the mitochondrial pathways for oxidation and ROS generation, thereby sustaining cancer cell survival in hypoxia. PMID:29256392

Metformin suppresses cancer initiation and progression in genetic mouse models of pancreatic cancer.

PubMed

Chen, Ke; Qian, Weikun; Jiang, Zhengdong; Cheng, Liang; Li, Jie; Sun, Liankang; Zhou, Cancan; Gao, Luping; Lei, Meng; Yan, Bin; Cao, Junyu; Duan, Wanxing; Ma, Qingyong

2017-07-24

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-associated mortality worldwide with an overall five-year survival rate less than 7%. Accumulating evidence has revealed the cancer preventive and therapeutic effects of metformin, one of the most widely prescribed medications for type 2 diabetes mellitus. However, its role in pancreatic cancer is not fully elucidated. Herein, we aimed to further study the preventive and therapeutic effects of metformin in genetically engineered mouse models of pancreatic cancer. LSL-Kras G12D/+ ; Pdx1-Cre (KC) mouse model was established to investigate the effect of metformin in pancreatic tumorigenesis suppression; LSL-Kras G12D/+ ; Trp53 fl/+ ; Pdx1-Cre (KPC) mouse model was used to evaluate the therapeutic efficiency of metformin in PDAC. Chronic pancreatitis was induced in KC mice by peritoneal injection of cerulein. Following metformin treatment, pancreatic acinar-to-ductal metaplasia (ADM) and mouse pancreatic intraepithelial neoplasia (mPanIN) were decreased in KC mice. Chronic pancreatitis induced a stroma-rich and duct-like structure and increased the formation of ADM and mPanIN lesions, in line with an increased cytokeratin 19 (CK19)-stained area. Metformin treatment diminished chronic pancreatitis-mediated ADM and mPanIN formation. In addition, it alleviated the percent area of Masson's trichrome staining, and decreased the number of Ki67-positive cells. In KPC mice, metformin inhibited tumor growth and the incidence of abdominal invasion. More importantly, it prolonged the overall survival. Metformin inhibited pancreatic cancer initiation, suppressed chronic pancreatitis-induced tumorigenesis, and showed promising therapeutic effect in PDAC.

Anticonvulsant effects of a triheptanoin diet in two mouse chronic seizure models

PubMed Central

Willis, Sarah; Stoll, James; Sweetman, Lawrence; Borges, Karin

2010-01-01

We hypothesized that in epileptic brains citric acid cycle intermediate levels may be deficient leading to hyperexcitability. Anaplerosis is the metabolic refilling of deficient metabolites. Our goal was to determine the anticonvulsant effects of feeding triheptanoin, the triglyceride of anaplerotic heptanoate. CF1 mice were fed 0-35% calories from triheptanoin. Body weights and dietary intake were similar in mice fed triheptanoin vs. standard diet. Triheptanoin feeding increased blood propionyl-carnitine levels, signifying its metabolism. 35%, but not 20%, triheptanoin delayed development of corneal kindled seizures. After pilocarpine-induced status epilepticus (SE), triheptanoin feeding increased the pentylenetetrazole tonic seizure threshold during the chronically epileptic stage. Mice in the chronically epileptic stage showed various changes in brain metabolite levels, including a reduction in malate. Triheptanoin feeding largely restored a reduction in propionyl-CoA levels and increased methylmalonyl-CoA levels in SE mice. In summary, triheptanoin was anticonvulsant in two chronic mouse models and increased levels of anaplerotic precursor metabolites in epileptic mouse brains. The mechanisms of triheptanoin's effects and its efficacy in humans suffering from epilepsy remain to be determined. PMID:20691264

Neural stem/progenitor cell properties of glial cells in the adult mouse auditory nerve

PubMed Central

Lang, Hainan; Xing, Yazhi; Brown, LaShardai N.; Samuvel, Devadoss J.; Panganiban, Clarisse H.; Havens, Luke T.; Balasubramanian, Sundaravadivel; Wegner, Michael; Krug, Edward L.; Barth, Jeremy L.

2015-01-01

The auditory nerve is the primary conveyor of hearing information from sensory hair cells to the brain. It has been believed that loss of the auditory nerve is irreversible in the adult mammalian ear, resulting in sensorineural hearing loss. We examined the regenerative potential of the auditory nerve in a mouse model of auditory neuropathy. Following neuronal degeneration, quiescent glial cells converted to an activated state showing a decrease in nuclear chromatin condensation, altered histone deacetylase expression and up-regulation of numerous genes associated with neurogenesis or development. Neurosphere formation assays showed that adult auditory nerves contain neural stem/progenitor cells (NSPs) that were within a Sox2-positive glial population. Production of neurospheres from auditory nerve cells was stimulated by acute neuronal injury and hypoxic conditioning. These results demonstrate that a subset of glial cells in the adult auditory nerve exhibit several characteristics of NSPs and are therefore potential targets for promoting auditory nerve regeneration. PMID:26307538

Histological Image Processing Features Induce a Quantitative Characterization of Chronic Tumor Hypoxia

PubMed Central

Grabocka, Elda; Bar-Sagi, Dafna; Mishra, Bud

2016-01-01

Hypoxia in tumors signifies resistance to therapy. Despite a wealth of tumor histology data, including anti-pimonidazole staining, no current methods use these data to induce a quantitative characterization of chronic tumor hypoxia in time and space. We use image-processing algorithms to develop a set of candidate image features that can formulate just such a quantitative description of xenographed colorectal chronic tumor hypoxia. Two features in particular give low-variance measures of chronic hypoxia near a vessel: intensity sampling that extends radially away from approximated blood vessel centroids, and multithresholding to segment tumor tissue into normal, hypoxic, and necrotic regions. From these features we derive a spatiotemporal logical expression whose truth value depends on its predicate clauses that are grounded in this histological evidence. As an alternative to the spatiotemporal logical formulation, we also propose a way to formulate a linear regression function that uses all of the image features to learn what chronic hypoxia looks like, and then gives a quantitative similarity score once it is trained on a set of histology images. PMID:27093539

Cortical delta-opioid receptors potentiate K+ homeostasis during anoxia and oxygen-glucose deprivation.

PubMed

Chao, Dongman; Donnelly, David F; Feng, Yin; Bazzy-Asaad, Alia; Xia, Ying

2007-02-01

Central neurons are extremely vulnerable to hypoxic/ischemic insult, which is a major cause of neurologic morbidity and mortality as a consequence of neuronal dysfunction and death. Our recent work has shown that delta-opioid receptor (DOR) is neuroprotective against hypoxic and excitotoxic stress, although the underlying mechanisms remain unclear. Because hypoxia/ischemia disrupts ionic homeostasis with an increase in extracellular K(+), which plays a role in neuronal death, we asked whether DOR activation preserves K(+) homeostasis during hypoxic/ischemic stress. To test this hypothesis, extracellular recordings with K(+)-sensitive microelectrodes were performed in mouse cortical slices under anoxia or oxygen-glucose deprivation (OGD). The main findings in this study are that (1) DOR activation with [D-Ala(2), D-Leu(5)]-enkephalinamide attenuated the anoxia- and OGD-induced increase in extracellular K(+) and decrease in DC potential in cortical slices; (2) DOR inhibition with naltrindole, a DOR antagonist, completely abolished the DOR-mediated prevention of increase in extracellular K(+) and decrease in DC potential; (3) inhibition of protein kinase A (PKA) with N-(2-[p-bromocinnamylamino]-ethyl)-5-isoquinolinesulfonamide dihydrochloride had no effect on the DOR protection; and (4) inhibition of protein kinase C (PKC) with chelerythrine chloride reduced the DOR protection, whereas the PKC activator (phorbol 12-myristate 13-acetate) mimicked the effect of DOR activation on K(+) homeostasis. These data suggest that activation of DOR protects the cortex against anoxia- or ODG-induced derangement of potassium homeostasis, and this protection occurs via a PKC-dependent and PKA-independent pathway. We conclude that an important aspect of DOR-mediated neuroprotection is its early action against derangement of K(+) homeostasis during anoxia or ischemia.

Adrenergic Signaling: A Targetable Checkpoint Limiting Development of the Antitumor Immune Response.

PubMed

Qiao, Guanxi; Chen, Minhui; Bucsek, Mark J; Repasky, Elizabeth A; Hylander, Bonnie L

2018-01-01

An immune response must be tightly controlled so that it will be commensurate with the level of response needed to protect the organism without damaging normal tissue. The roles of cytokines and chemokines in orchestrating these processes are well known, but although stress has long been thought to also affect immune responses, the underlying mechanisms were not as well understood. Recently, the role of nerves and, specifically, the sympathetic nervous system, in regulating immune responses is being revealed. Generally, an acute stress response is beneficial but chronic stress is detrimental because it suppresses the activities of effector immune cells while increasing the activities of immunosuppressive cells. In this review, we first discuss the underlying biology of adrenergic signaling in cells of both the innate and adaptive immune system. We then focus on the effects of chronic adrenergic stress in promoting tumor growth, giving examples of effects on tumor cells and immune cells, explaining the methods commonly used to induce stress in preclinical mouse models. We highlight how this relates to our observations that mandated housing conditions impose baseline chronic stress on mouse models, which is sufficient to cause chronic immunosuppression. This problem is not commonly recognized, but it has been shown to impact conclusions of several studies of mouse physiology and mouse models of disease. Moreover, the fact that preclinical mouse models are chronically immunosuppressed has critical ramifications for analysis of any experiments with an immune component. Our group has found that reducing adrenergic stress by housing mice at thermoneutrality or treating mice housed at cooler temperatures with β-blockers reverses immunosuppression and significantly improves responses to checkpoint inhibitor immunotherapy. These observations are clinically relevant because there are numerous retrospective epidemiological studies concluding that cancer patients who were taking β-blockers have better outcomes. Clinical trials testing whether β-blockers can be repurposed to improve the efficacy of traditional and immunotherapies in patients are on the horizon.

Adrenergic Signaling: A Targetable Checkpoint Limiting Development of the Antitumor Immune Response

PubMed Central

Qiao, Guanxi; Chen, Minhui; Bucsek, Mark J.; Repasky, Elizabeth A.; Hylander, Bonnie L.

2018-01-01

An immune response must be tightly controlled so that it will be commensurate with the level of response needed to protect the organism without damaging normal tissue. The roles of cytokines and chemokines in orchestrating these processes are well known, but although stress has long been thought to also affect immune responses, the underlying mechanisms were not as well understood. Recently, the role of nerves and, specifically, the sympathetic nervous system, in regulating immune responses is being revealed. Generally, an acute stress response is beneficial but chronic stress is detrimental because it suppresses the activities of effector immune cells while increasing the activities of immunosuppressive cells. In this review, we first discuss the underlying biology of adrenergic signaling in cells of both the innate and adaptive immune system. We then focus on the effects of chronic adrenergic stress in promoting tumor growth, giving examples of effects on tumor cells and immune cells, explaining the methods commonly used to induce stress in preclinical mouse models. We highlight how this relates to our observations that mandated housing conditions impose baseline chronic stress on mouse models, which is sufficient to cause chronic immunosuppression. This problem is not commonly recognized, but it has been shown to impact conclusions of several studies of mouse physiology and mouse models of disease. Moreover, the fact that preclinical mouse models are chronically immunosuppressed has critical ramifications for analysis of any experiments with an immune component. Our group has found that reducing adrenergic stress by housing mice at thermoneutrality or treating mice housed at cooler temperatures with β-blockers reverses immunosuppression and significantly improves responses to checkpoint inhibitor immunotherapy. These observations are clinically relevant because there are numerous retrospective epidemiological studies concluding that cancer patients who were taking β-blockers have better outcomes. Clinical trials testing whether β-blockers can be repurposed to improve the efficacy of traditional and immunotherapies in patients are on the horizon. PMID:29479349

Social psychogenic stress promotes the development of endometriosis in mouse.

PubMed

Guo, Sun-Wei; Zhang, Qi; Liu, Xishi

2017-03-01

Exposure to chronic stress before and well after the induction of endometriosis is reported to increase lesion sizes in rats, but it is unclear whether stress, exposed shortly after the induction of endometriosis, would also promote the development of endometriosis, nor is it clear what the underlying possible molecular mechanism is. This study was undertaken to test the hypothesis that chronic stress can promote the development of endometriosis. A prospective randomized mouse experiment was conducted that subjected mice with induced endometriosis to predator stress. In addition, a cross-sectional immunohistochemistry study was performed in ectopic and eutopic endometrial tissue samples from age- and roughly menstrual phase-matched women with ovarian endometriomas. It was found that the chronic psychogenic stress induced epigenetic changes in the hippocampus in mouse independent of endometriosis. It was also found that chronic psychogenic stress induced epigenetic changes in the hippocampus of mice with endometriosis, and seemingly activated the adrenergic signalling in ectopic endometrium, resulting in increased angiogenesis and accelerated growth of endometriotic lesions. Thus, chronic psychogenic stress promotes endometriosis development, raising the possibility that the use of anti-depressants in cases of prolonged and intense stress might forestall the negative impact of stress on the development of endometriosis. Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Caffeic Acid Inhibits Chronic UVB-Induced Cellular Proliferation Through JAK-STAT3 Signaling in Mouse Skin.

PubMed

Agilan, Balupillai; Rajendra Prasad, N; Kanimozhi, Govindasamy; Karthikeyan, Ramasamy; Ganesan, Muthusamy; Mohana, Shanmugam; Velmurugan, Devadasan; Ananthakrishnan, Dhanapalan

2016-05-01

Signal transducers and activators of transcription 3 (STAT3) play a critical role in inflammation, proliferation and carcinogenesis. Inhibition of JAK-STAT3 signaling is proved to be a novel target for prevention of UVB-induced skin carcinogenesis. In this study, chronic UVB irradiation (180 mJ cm(-2) ; weekly thrice for 30 weeks) induces the expression of IL-10 and JAK1 that eventually activates the STAT3 which leads to the transcription of proliferative and antiapoptotic markers such as PCNA, Cyclin-D1, Bcl2 and Bcl-xl, respectively. Caffeic acid (CA) inhibits JAK-STAT3 signaling, thereby induces apoptotic cell death by upregulating Bax, Cytochrome-C, Caspase-9 and Caspase-3 expression in mouse skin. Furthermore, TSP-1 is an antiangiogeneic protein, which is involved in the inhibition of angiogenesis and proliferation. Chronic UVB exposure decreased the expression of TSP-1 and pretreatment with CA prevented the UVB-induced loss of TSP-1 in UVB-irradiated mouse skin. Thus, CA offers protection against UVB-induced photocarcinogenesis probably through modulating the JAK-STAT3 in the mouse skin. © 2016 The American Society of Photobiology.

Novel Genetic Models to Study the Role of Inflammation in Brain Injury-Induced Alzheimer’s Pathology

DTIC Science & Technology

2015-12-01

Clinic. (2013) “Opposing Acute and Chronic Effects of Traumatic Brain Injury in a Mouse Model of Alzheimer’s Disease” Kokiko-Cochran, O.N.  Annual...nanosymposium, Washington, D.C. (2014) “ Traumatic brain injury induces a distinct macrophage response at acute and chronic time points in a mouse model...SUPPLEMENTARY NOTES 14. ABSTRACT Individuals exposed to traumatic brain injury (TBI) are at a greatly increased risk for developing a number of

Neurotoxocarosis alters myelin protein gene transcription and expression.

PubMed

Heuer, Lea; Beyerbach, Martin; Lühder, Fred; Beineke, Andreas; Strube, Christina

2015-06-01

Neurotoxocarosis is an infection of the central nervous system caused by migrating larvae of the common dog and cat roundworms (Toxocara canis and Toxocara cati), which are zoonotic agents. As these parasites are prevalent worldwide and neuropathological and molecular investigations on neurotoxocarosis are scare, this study aims to characterise nerve fibre demyelination associated with neurotoxocarosis on a molecular level. Transcription of eight myelin-associated genes (Cnp, Mag, Mbp, Mog, Mrf-1, Nogo-A, Plp1, Olig2) was determined in the mouse model during six time points of the chronic phase of infection using qRT-PCR. Expression of selected proteins was analysed by Western blotting or immunohistochemistry. Additionally, demyelination and neuronal damage were investigated histologically. Significant differences (p ≤ 0.05) between transcription rates of T. canis-infected and uninfected control mice were detected for all analysed genes while T. cati affected five of eight investigated genes. Interestingly, 2', 3 ´-cyclic nucleotide 3'-phosphodiesterase (Cnp) and myelin oligodendrocyte glycoprotein (Mog) were upregulated in both T. canis- and T. cati-infected mice preceding demyelination. Later, CNPase expression was additionally enhanced. As expected, myelin basic protein (Mbp) was downregulated in cerebra and cerebella of T. canis-infected mice when severe demyelination was present 120 days post infectionem (dpi). The transcriptional pattern observed in the present study appears to reflect direct traumatic and hypoxic effects of larval migration as well as secondary processes including host immune reactions, demyelination and attempts to remyelinate damaged areas.

Acid-Sensitive Sheddable PEGylated, Mannose-Modified Nanoparticles Increase the Delivery of Betamethasone to Chronic Inflammation Sites in a Mouse Model.

PubMed

O'Mary, Hannah L; Aldayel, Abdulaziz M; Valdes, Solange A; Naguib, Youssef W; Li, Xu; Salvady, Karun; Cui, Zhengrong

2017-06-05

Inflammation is implicated in a host of chronic illnesses. Within these inflamed tissues, the pH of the microenvironment is decreased and immune cells, particularly macrophages, infiltrate the area. Additionally, the vascular integrity of these sites is altered with increased fenestrations between endothelial cells. These distinctive properties may be exploited to enhance targeted delivery of anti-inflammatory therapies. Using a mouse model of chronic inflammation, we previously showed that acid-sensitive sheddable PEGylation increases the distribution and retention of nanoparticles in chronic inflammation sites. Here we demonstrated that surface modification of the acid-sensitive sheddable PEGylated nanoparticles with mannose, a ligand to mannose receptors present in chronic inflammation sites, significantly increases the targeted delivery of the nanoparticles to these areas. Furthermore, we showed that the acid-sensitive sheddable PEGylated, mannose-modified nanoparticles are able to significantly increase the delivery of betamethasone-21-acetate (BA), a model anti-inflammatory compound, to chronic inflammation sites as compared to free BA. These results highlight the ability to engineer formulations to target chronic inflammation sites by exploiting the microenvironment of these regions.

Ibuprofen does not reverse ventilatory acclimatization to chronic hypoxia.

PubMed

De La Zerda, D J; Stokes, J A; Do, J; Go, A; Fu, Z; Powell, F L

2017-07-27

Ventilatory acclimatization to hypoxia involves an increase in the acute hypoxic ventilatory response that is blocked by non-steroidal anti-inflammatory drugs administered during sustained hypoxia. We tested the hypothesis that inflammatory signals are necessary to sustain ventilatory acclimatization to hypoxia once it is established. Adult, rats were acclimatized to normoxia or chronic hypoxia (CH, [Formula: see text] =70Torr) for 11-12days and treated with ibuprofen or saline for the last 2days of hypoxia. Ventilation, metabolic rate, and arterial blood gas responses to O 2 and CO 2 were not affected by ibuprofen after acclimatization had been established. Immunohistochemistry and image analysis showed acute (1h) hypoxia activated microglia in a medullary respiratory center (nucleus tractus solitarius, NTS) and this was blocked by ibuprofen administered from the beginning of hypoxic exposure. Microglia returned to the control state after 7days of CH and were not affected by ibuprofen administered for 2 more days of CH. In contrast, NTS astrocytes were activated by CH but not acute hypoxia and activation was not reversed by administering ibuprofen for the last 2days of CH. Hence, ibuprofen cannot reverse ventilatory acclimatization or astrocyte activation after they have been established by sustained hypoxia. The results are consistent with a model for microglia activation or other ibuprofen-sensitive processes being necessary for the induction but not maintenance of ventilatory acclimatization to hypoxia. Copyright © 2017 Elsevier B.V. All rights reserved.

Hypoxia triggers short term potentiation of phrenic motoneuron discharge after chronic cervical spinal cord injury

PubMed Central

Lee, Kun-Ze; Sandhu, Milapjit S.; Dougherty, Brendan J.; Reier, Paul J.; Fuller, David D.

2014-01-01

Repeated exposure to hypoxia can induce spinal neuroplasticity as well as respiratory and somatic motor recovery after spinal cord injury (SCI). The purpose of the present study was to define the capacity for a single bout of hypoxia to trigger short-term plasticity in phrenic output after cervical SCI, and to determine the phrenic motoneuron (PhrMN) bursting and recruitment patterns underlying the response. Hypoxia-induced short term potentiation (STP) of phrenic motor output was quantified in anesthetized rats 11 wks following lateral spinal hemisection at C2 (C2Hx). A 3-min hypoxic episode (12–14% O2) always triggered STP of inspiratory burst amplitude, the magnitude of which was greater in phrenic bursting ipsilateral vs. contralateral to C2Hx. We next determined if STP could be evoked in recruited (silent) PhrMNs ipsilateral to C2Hx. Individual PhrMN action potentials were recorded during and following hypoxia using a “single fiber” approach. STP of bursting activity did not occur in cells initiating bursting at inspiratory onset, but was robust in recruited PhrMNs as well as previously active cells initiating bursting later in the inspiratory effort. We conclude that following chronic C2Hx, a single bout of hypoxia triggers recruitment of PhrMNs in the ipsilateral spinal cord with bursting that persists beyond the hypoxic exposure. The results provide further support for the use of short bouts of hypoxia as a neurorehabilitative training modality following SCI. PMID:25448009

Long non-coding RNA UCA1 upregulation promotes the migration of hypoxia-resistant gastric cancer cells through the miR-7-5p/EGFR axis.

PubMed

Yang, Zichang; Shi, Xiaonan; Li, Ce; Wang, Xiaoxun; Hou, Kezuo; Li, Zhi; Zhang, Xiaojie; Fan, Yibo; Qu, Xiujuan; Che, Xiaofang; Liu, Yunpeng

2018-05-01

A variety of solid tumors are surrounded by a hypoxic microenvironment, which is known to be associated with high metastatic capability and resistance to various clinical therapies, contributing to a poor survival rate for cancer patients. Although the majority of previous studies on tumor-associated hypoxia have focused on acute hypoxia, chronic hypoxia more closely mimics the actual hypoxic microenvironment of a tumor. In this study, two novel hypoxia-resistant gastric cancer (HRGC) cell lines which could grow normally in 2% oxygen were established. The long non-coding RNA UCA1 was upregulated in HRGC cells, which promoted their migration. Bioinformatics analysis and a luciferase reporter assay showed that miR-7-5p could bind to specific sites of UCA1 to regulate the target EGFR through competitive endogenous RNA function. UCA1 directly interacted with miR-7-5p and decreased the binding of miR-7-5p to the EGFR 3'-untranslated region, which suppressed the degradation of EGFR mRNA by miR-7-5p. Therefore, long-term hypoxia induced UCA1 to promote cell migration by enhancing the expression of EGFR. This study thus reveals a new mechanism by which a hypoxic microenvironment promotes tumor metastasis, and highlights UCA1 as a potential biomarker for predicting the metastasis of gastric cancer to guide clinical treatment. Copyright © 2018 Elsevier Inc. All rights reserved.

Estimation of changes in alveolar-arterial oxygen gradient induced by hypoxia.

PubMed

Hoffstein, V; Duguid, N; Zamel, N; Rebuck, A S

1984-11-01

The alveolar-arterial oxygen tension difference provides a useful clinical indication of ventilation-blood flow mismatching in the lungs. In some clinical situations involving alveolar hypoxia (e.g., patients with chronic obstructive lung disease flying in commercial aircraft or normal humans at high altitudes) it would be useful to know this tension difference to predict the likely arterial PO2 under such potentially stressful conditions. Such estimates would require multiple arterial punctures performed under a variety of trying circumstances, conditions usually far distant from a suitable analytic facility. Consequently, we induced controlled hypoxia in 23 healthy humans and calculated changes in the alveolar-arterial oxygen tension difference during the hypoxic challenge test. We plotted this difference as a function of the alveolar oxygen tension over a range from 35 to 110 mm Hg. In addition to a series of control studies in which multiple arterial blood samples were obtained, we calculated arterial PO2 by converting the arterial oxyhemoglobin saturation (measured with an ear oximeter) into partial pressure of oxygen. During hypoxic procedures in which levels of oxygenation fell on the steep section of the oxyhemoglobin dissociation curve, fixing PCO2 at constant predetermined levels allowed accurate predictions of arterial PO2. We were able to demonstrate that the alveolar-arterial oxygen tension difference narrowed with decreasing alveolar oxygen tension, and that measurement with an ear oximeter provided data that allowed a reasonable estimate of the tension difference during hypoxic conditions.

Exercise during Short-Term and Long-Term Continuous Exposure to Hypoxia Exacerbates Sleep-Related Periodic Breathing.

PubMed

Tellez, Helio Fernandez; Morrison, Shawnda A; Neyt, Xavier; Mairesse, Olivier; Piacentini, Maria Francesca; Macdonald-Nethercott, Eoin; Pangerc, Andrej; Dolenc-Groselj, Leja; Eiken, Ola; Pattyn, Nathalie; Mekjavic, Igor B; Meeusen, Romain

2016-04-01

Exposure to hypoxia elevates chemosensitivity, which can lead to periodic breathing. Exercise impacts gas exchange, altering chemosensitivity; however, interactions between sleep, exercise and chronic hypoxic exposure have not been examined. This study investigated whether exercise exacerbates sleep-related periodic breathing in hypoxia. Two experimental phases. Short-Term Phase: a laboratory controlled, group-design study in which 16 active, healthy men (age: 25 ± 3 y, height: 1.79 ± 0.06 m, mass: 74 ± 8 kg) were confined to a normobaric hypoxic environment (FIO2 = 0.139 ± 0.003, 4,000 m) for 10 days, after random assignment to a sedentary (control, CON) or cycle-exercise group (EX). Long-Term Phase: conducted at the Concordia Antarctic Research Station (3,800 m equivalent at the Equator) where 14 men (age: 36 ± 9 y, height: 1.77 ± 0.09 m, mass: 75 ± 10 kg) lived for 12-14 months, continuously confined. Participants were stratified post hoc based on self-reported physical activity levels. We quantified apnea-hypopnea index (AHI) and physical activity variables. Short-Term Phase: mean AHI scores were significantly elevated in the EX group compared to CON (Night1 = CON: 39 ± 51, EX: 91 ± 59; Night10 = CON: 32 ± 32, EX: 92 ± 48; P = 0.046). Long-Term Phase: AHI was correlated to mean exercise time (R(2) = 0.4857; P = 0.008) and the coefficient of variation in night oxyhemoglobin saturation (SpO2; R(2) = 0.3062; P = 0.049). Data indicate that exercise (physical activity) per se affects night SpO2 concentrations and AHI after a minimum of two bouts of moderate-intensity hypoxic exercise, while habitual physical activity in hypobaric hypoxic confinement affects breathing during sleep, up to 13+ months' duration. © 2016 Associated Professional Sleep Societies, LLC.

Transepithelial Ion Transport is Suppressed in Hypoxic Sinonasal Epithelium

PubMed Central

Blount, Angela; Zhang, Shaoyan; Chestnut, Michael; Hixon, Brian; Skinner, Daniel; Sorscher, Eric J.; Woodworth, Bradford A.

2011-01-01

Objectives/Hypothesis Sinonasal respiratory epithelial mucociliary clearance (MCC) is dependent on the transepithelial transport of ions such as Cl−. The objectives of the present study were to investigate the role of oxygen restriction in 1) Cl− transport across primary sinonasal epithelial monolayers, 2) expression of the apical Cl− channels CFTR and TMEM16A, and 3) the pathogenesis of chronic rhinosinusitis (CRS). Study Design In vitro investigation. Methods Murine nasal septal epithelial (MNSE, wild type) and human sinonasal epithelial (HSNE) cultures were incubated under hypoxic conditions (1% O2, 5% CO2). Cultures were mounted in Ussing chambers for ion transport measurements. CFTR and TMEM16A expression were measured using quantitative RT-PCR. Results The change in short-circuit current (ΔISC (µA/cm2) attributable to CFTR (forskolin-stimulated) was significantly decreased due to a 12 hour hypoxia exposure in both MNSE (13.55+/− 0.46 vs. 19.23+/−0.18) and HSNE (19.55+/−0.56 vs. 25.49+/−1.48 (control); p<0.05. TMEM16A (UTP-stimulated transport) was inhibited by 48 hours of hypoxic exposure in MNSE (15.92+/−2.87 vs. 51.44+/−3.71(control) p<0.05] and by 12 hours of hypoxic exposure in HSNE (16.75+/−0.68 vs. 24.15+/−1.35 (control). Quantitative RT-PCR (reported as relative mRNA levels+/−S.D.) demonstrated significant reductions in both CFTR and TMEM16A mRNA expression in MNSE and HSNE due to airway epithelial hypoxia. Conclusions Sinonasal epithelial CFTR and TMEM16A-mediated Cl− transport and mRNA expression were robustly decreased in an oxygen restricted environment. The findings in the present study indicate persistent hypoxia may lead to acquired defects in sinonasal Cl− transport in a fashion likely to confer mucociliary dysfunction in CRS. Level of Evidence 1b PMID:22024847

Persistence of neoangiogenesis and cardiomyocyte divisions in right ventricular myocardium of rats born and raised in hypoxic conditions.

PubMed

Moravec, Mireille; Turek, Zdenek; Moravec, Josef

2002-03-01

Effects of chronic hypoxia on capillary and myocyte growth were examined in rats born and raised in a low pressure chamber (equivalent of 3500 m a.s.l.). The animals were sacrificed at the age of 3 months and their hearts were used to study right ventricular growth and vascularization. The results of our cytological and morphometric analysis suggest the persistence of capillary neogenesis in this particular model of cardiac hypertrophy. Under the optical microscope, we observed significant changes in capillary spatial patterns such as the presence of sinusoids and irregular capillary sprouts. This resulted in a significant shortening of the effective diffusion distance and in a slight decrease in the calculated diameter of the Krogh cylinder. Concomitant to the remodeling of the terminal capillary network, the right ventricular myocardium of hypoxic rats exhibited peculiar changes in myocyte cytology. The principal alteration consisted in the ectopic subsarcolemmal location of some of muscle cell nuclei which appeared enlarged and rounded, sometimes irregularly folded. At the E. M. level, they presented chromatine condensation, nucleolemmal folding and, occasionally, nuclear splitting. Irregular chromatin densifications at the equatorial position were also encountered but we never observed nucleolemmal dissolution or typical metaphase plaques which excludes the presence of mitotic division. Some of the marginalized nuclei were progressively excluded from original binucleate cells into small cytoplasmic processes that invaded the adjacent neo-formed pericapillar spaces and gave rise to small well-organized cardiomyocytes. This apparent fragmentation of cardiomyocytes may evoke the description of the apoptotic process which is believed to be stimulated in hypoxic tissues. However, we could not confirm that myocyte fragmentation that we describe is followed by shrinkage necrosis or by any mobilization of adjacent resident cells. Nuclear exclusions into pericapillary myocyte sprouts may, therefore, reflect amitotic divisions of polyploid cardiomyocytes which contribute to the persistence of hyperplasic growth in right ventricular myocardium in hearts of rats exposed to chronic hypoxia during their early postnatal life. Par analogie with our data, it can be expected that an appropriate stimulation of angiogenesis in hearts of adult animals attenuates some of cytological and functional drawbacks that accompany hypertrophic cardiomyopathies of other etiologies.

Combination therapy with BPTES nanoparticles and metformin targets the metabolic heterogeneity of pancreatic cancer

PubMed Central

Elgogary, Amira; Xu, Qingguo; Poore, Brad; Alt, Jesse; Zimmermann, Sarah C.; Zhao, Liang; Fu, Jie; Chen, Baiwei; Xia, Shiyu; Liu, Yanfei; Neisser, Marc; Nguyen, Christopher; Lee, Ramon; Park, Joshua K.; Reyes, Juvenal; Hartung, Thomas; Rojas, Camilo; Rais, Rana; Tsukamoto, Takashi; Semenza, Gregg L.; Hanes, Justin; Slusher, Barbara S.; Le, Anne

2016-01-01

Targeting glutamine metabolism via pharmacological inhibition of glutaminase has been translated into clinical trials as a novel cancer therapy, but available drugs lack optimal safety and efficacy. In this study, we used a proprietary emulsification process to encapsulate bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide (BPTES), a selective but relatively insoluble glutaminase inhibitor, in nanoparticles. BPTES nanoparticles demonstrated improved pharmacokinetics and efficacy compared with unencapsulated BPTES. In addition, BPTES nanoparticles had no effect on the plasma levels of liver enzymes in contrast to CB-839, a glutaminase inhibitor that is currently in clinical trials. In a mouse model using orthotopic transplantation of patient-derived pancreatic tumor tissue, BPTES nanoparticle monotherapy led to modest antitumor effects. Using the HypoxCR reporter in vivo, we found that glutaminase inhibition reduced tumor growth by specifically targeting proliferating cancer cells but did not affect hypoxic, noncycling cells. Metabolomics analyses revealed that surviving tumor cells following glutaminase inhibition were reliant on glycolysis and glycogen synthesis. Based on these findings, metformin was selected for combination therapy with BPTES nanoparticles, which resulted in significantly greater pancreatic tumor reduction than either treatment alone. Thus, targeting of multiple metabolic pathways, including effective inhibition of glutaminase by nanoparticle drug delivery, holds promise as a novel therapy for pancreatic cancer. PMID:27559084

HYPOXIA-ACTIVATED PRO-DRUG TH-302 EXHIBITS POTENT TUMOUR SUPPRESSIVE ACTIVITY AND COOPERATES WITH CHEMOTHERAPY AGAINST OSTEOSARCOMA

PubMed Central

Liapis, Vasilios; Labrinidis, Agatha; Zinonos, Irene; Hay, Shelley; Ponomarev, Vladimir; Panagopoulos, Vasilios; DeNichilo, Mark; Ingman, Wendy; Atkins, Gerald J.; Findlay, David M.; Zannettino, Andrew CW.; Evdokiou, Andreas

2015-01-01

Tumour hypoxia is a major cause of treatment failure for a variety of malignancies. However, tumour hypoxia also offers treatment opportunities, exemplified by the development compounds that target hypoxic regions within tumours. TH-302 is a pro-drug created by the conjugation of 2-nitroimidazole to bromo-isophosphoramide (Br-IPM). When TH-302 is delivered to regions of hypoxia, Br-IPM, the DNA cross linking toxin, is released. In this study we assessed the cytotoxic activity of TH-302 against osteosarcoma cells in vitro and evaluated its anticancer efficacy as a single agent, and in combination with doxorubicin, in an orthotopic mouse model of human osteosarcoma (OS). In vitro, TH-302 was potently cytotoxic to osteosarcoma cells selectively under hypoxic conditions, whereas primary normal human osteoblasts were protected. Animals transplanted with OS cells directly into their tibiae and left untreated developed mixed osteolytic/osteosclerotic bone lesions and subsequently developed lung metastases. TH-302 reduced tumor burden in bone and cooperated with doxorubicin to protect bone from osteosarcoma induced bone destruction, while it also reduced lung metastases. TH-302 may therefore be an attractive therapeutic agent with strong activity as a single agent and in combination with chemotherapy against OS. PMID:25444931

Hypoxia-activated pro-drug TH-302 exhibits potent tumor suppressive activity and cooperates with chemotherapy against osteosarcoma.

PubMed

Liapis, Vasilios; Labrinidis, Agatha; Zinonos, Irene; Hay, Shelley; Ponomarev, Vladimir; Panagopoulos, Vasilios; DeNichilo, Mark; Ingman, Wendy; Atkins, Gerald J; Findlay, David M; Zannettino, Andrew C W; Evdokiou, Andreas

2015-02-01

Tumor hypoxia is a major cause of treatment failure for a variety of malignancies. However, tumor hypoxia also offers treatment opportunities, exemplified by the development compounds that target hypoxic regions within tumors. TH-302 is a pro-drug created by the conjugation of 2-nitroimidazole to bromo-isophosphoramide (Br-IPM). When TH-302 is delivered to regions of hypoxia, Br-IPM, the DNA cross linking toxin, is released. In this study we assessed the cytotoxic activity of TH-302 against osteosarcoma cells in vitro and evaluated its anticancer efficacy as a single agent, and in combination with doxorubicin, in an orthotopic mouse model of human osteosarcoma (OS). In vitro, TH-302 was potently cytotoxic to osteosarcoma cells selectively under hypoxic conditions, whereas primary normal human osteoblasts were protected. Animals transplanted with OS cells directly into their tibiae and left untreated developed mixed osteolytic/osteosclerotic bone lesions and subsequently developed lung metastases. TH-302 reduced tumor burden in bone and cooperated with doxorubicin to protect bone from osteosarcoma induced bone destruction, while it also reduced lung metastases. TH-302 may therefore be an attractive therapeutic agent with strong activity as a single agent and in combination with chemotherapy against OS. Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.

Imaging biomarkers to monitor response to the hypoxia-activated prodrug TH-302 in the MiaPaCa2 flank xenograft model.

PubMed

Cárdenas-Rodríguez, Julio; Li, Yuguo; Galons, Jean-Philippe; Cornnell, Heather; Gillies, Robert J; Pagel, Mark D; Baker, Amanda F

2012-09-01

TH-302, a hypoxia-activated anticancer prodrug, was evaluated for antitumor activity and changes in dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) in a mouse model of pancreatic cancer. TH-302 monotherapy resulted in a significant delay in tumor growth compared to vehicle-treated controls. TH-302 treatment was also associated with a significant decrease in the volume transfer constant (K(trans)) compared to vehicle-treated controls 1 day following the first dose measured using DCE-MRI. This early decrease in K(trans) following the first dose as measured is consistent with selective killing of the hypoxic fraction of cells which are associated with enhanced expression of hypoxia inducible transcription factor-1 alpha that regulates expression of permeability and perfusion factors including vascular endothelial growth factor-A. No changes were observed in DW-MRI following treatment with TH-302, which may indicate that this technique is not sensitive enough to detect changes in small hypoxic fractions of the tumor targeted by TH-302. These results suggest that changes in tumor permeability and/or perfusion may be an early imaging biomarker for response to TH-302 therapy. Copyright © 2012 Elsevier Inc. All rights reserved.

Tumor control by hypoxia-specific chemotargeting of iron-oxide nanoparticle - Berberine complexes in a mouse model.

PubMed

Sreeja, S; Krishnan Nair, C K

2018-02-15

To evaluate the therapeutic efficacy of hypoxic cell-sensitizer Sanazole (SAN) -directed targeting of cytotoxic drug Berberine (BBN) and Iron-oxide nanoparticle (NP) complexes, to solid tumor in Swiss albino mice. NP-BBN-SAN complexes were characterized by FTIR, XRD, TEM and Nano-size analyzer. This complex was orally administered to mice-bearing solid tumor in hind limb. Tumor regression was analysed by measuring tumor volume. Cellular DNA damages were assessed by comet assay. Transcriptional expression of genes related to tumor hypoxia and apoptosis was evaluated by quantitative real-time PCR and morphological changes in tissues were analysed by histopathology. Also levels of antioxidants and tumor markers in tissues and serum biochemical parameters were analysed. Administration of NP-BBN-SAN complexes reduced tumor volume and studies were focussed on the underlying mechanisms. Extensive damage to cellular-DNA; down-regulated transcription of hif-1α, vegf, akt and bcl2; and up-regulated expression of bax and caspases, were observed in tumor. Results on tumor markers, antioxidant-status and serum parameters corroborated the molecular findings. Histopathology of tumor, liver and kidney revealed the therapeutic specificity of NP-BBN-SAN. Thus SAN and NP can be used for specific targeting of drugs, to hypoxic solid tumor, to improve therapeutic efficacy. Copyright © 2017. Published by Elsevier Inc.

Characteristic changes in brain electrical activity due to chronic hypoxia in patients with obstructive sleep apnea syndrome (OSAS): a combined EEG study using LORETA and omega complexity.

PubMed

Toth, Marton; Faludi, Bela; Wackermann, Jiri; Czopf, Jozsef; Kondakor, Istvan

2009-11-01

EEG background activity of patients with obstructive sleep apnea syndrome (OSAS, N = 25) was compared to that of normal controls (N = 14) to reflect alterations of brain electrical activity caused by chronic intermittent hypoxia in OSAS. Global and regional (left vs. right, anterior vs. posterior) measures of spatial complexity (Omega) were used to characterize the degree of spatial synchrony of EEG. Low resolution electromagnetic tomography (LORETA) was used to localize generators of EEG activity in separate frequency bands. Comparing patients to controls, lower Omega complexity was found globally and in the right hemisphere. Using LORETA, an increased medium frequency activity was seen bilaterally in the precuneus, paracentral and posterior cingulate cortex. These findings indicate that alterations caused by chronic hypoxia in brain electrical activity in regions associated with influencing emotional regulation, long-term memory and the default mode network. Global synchronization (lower Omega complexity) may indicate a significantly reduced number of relatively independent, parallel neural processes due to chronic global hypoxic state in apneic patients as well as over the right hemisphere.

[Effects of hypoxic acclimatization on myocardial sarcoplasmic reticulum ATPase and 45Ca2+ uptake in rats].

PubMed

Long, Chao-liang; Zhang, Yan-fang; Yin, Zhao-yun; Wang, Hai

2005-08-01

To study the effect of acute hypoxia and hypoxic acclimatization on myocardial function of rats. Eighteen male Wistar rats were randomly divided into three groups: normoxic control, acute hypoxia and intermittent hypoxic acclimatization group (n=6). After being exposed to hypoxia (8000 m) for 4 h before and after intermittent hypoxic acclimatization (3000 m and 5000 m, 14 d respectively, 4 h/d), the rats were decapitated and then myocardial sarcoplasmic reticulum (SR) were derived from cardiac muscles. Activities of Na+, K(+)-ATPase, Ca2+, Mg2(+)-ATPase in SR, phosphorylation of phospholamban (PLB) and the ability of 45Ca2+ uptake in SR were observed in all these three groups. 1) Hypoxia had no effects on the activity of Na+, K(+)-ATPase in rats myocardial SR of rats. 2) Compared with normoxic control rats, the activity of Ca2+, Mg2(+)-ATPase in myocardial SR of rats after acute hypoxia was reduced significantly (P<0.01). After intermittent hypoxic acclimatization, its activity increased significantly as compared with that of acute hypoxic rats (P<0.01). 3) The phosphorylation of PLB in acute hypoxic rats was reduced significantly compared with normoxic control rats. After intermittent hypoxic acclimatization, its phosphorylation was increased significantly compared with that of acute hypoxic rats. It suggests that hypoxic acclimatization could alleviate the inhibition of calcium pump. 4) The ability of 45Ca2+ uptake of SR in acute hypoxic rats was decreased significantly. After hypoxic acclimatization, its ability was strengthened significantly. These results suggest that the increased function of myocardial SR calcium pump, the strengthened phosphorylation of PLB to alleviate the inhibition of calcium pump and the increased function of Ca2+ transport in SR are the mechanisms of hypoxic acclimatization protecting cardiac functions from injury induced by severe hypoxia.

Effects of human recombinant erythropoietin on differentiation and distribution of erythroid progenitor cells on murine medullary and splenic erythropoiesis during hypoxia and post-hypoxia.

PubMed

Mide, S M; Huygens, P; Bozzini, C E; Fernandez Pol, J A

2001-01-01

Hemopoietic cells, the extracellular matrix, growth factors and the microenvironment are involved in the regulation of hemopoiesis. Although the regulation of erythropoiesis is well understood at the cellular level in vivo and in vitro, the role of hemopoietic sites of erythroid progenitors production has not been well defined in both steady state conditions and in stress erythropoiesis. In this study we examined the qualitative erythroid differentiation and quantitative changes of the erythroid progenitors in different erythropoietic organs during erythropoiesis of stress in a hypoxia-induced polycythemia and post-hypoxic changes in a mice model. Chronic intermittent exposure to hypobaric hypoxia induced polycythemia in mice and the post-hypoxic period was characterized by total suppression of erythropoiesis. The number and distribution in hemopoietic sites of Immature Erythroid Burst (BFU-EI), Mature Erythroid Burst (BFU-EM) and Erythroid Colony Forming Units (CFU-E) was evaluated in bone marrow and spleen of hypoxic and post-hypoxic mice after removal from the chamber. The number of BFU-EI and CFU-E, was evaluated in both femoral bone marrow and spleen of ex-hypoxic polycythemic mice, at two times intervals after the end of hypoxia. We found that in both bone marrow and spleen, the kinetics of the CFU-E pool was characterized by a sharp fall from above normal to lower than normal levels. BFU-EM increased from normal to higher than normal levels. These results have been correlated with both erythropoietin (EPO) and the erythropoietic activity. The results show that EPO levels largely control both the differentiation and the amplification of the CFU-E pool and they suggest that EPO may acts as a "survival factor" at the CFU-E level and/or increase the flow of cells from BFU-E to CFU-E. After the termination of the period of hypoxia and during post-hypoxia there was a reduction in EPO production which subsequently caused a depletion of the CFU-E population, indicating that the size of the CFU-E pool is EPO-dependent. After the injection of 1U of recombinant human erythropoietin (rHuEPO) the size of that pool was increased and the pool of BFU-EI was decreased. It is noteworthy that our studies show that the spleen functions as a large reservoir of erythroid precursors for hypoxia-induced stress erythropoiesis.

Inhibition of HIF-1{alpha} activity by BP-1 ameliorates adjuvant induced arthritis in rats

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

Shankar, J.; Thippegowda, P.B., E-mail: btprabha@uic.edu; Kanum, S.A.

Rheumatoid arthritis (RA) is a chronic inflammatory, angiogenic disease. Inflamed synovitis is a hallmark of RA which is hypoxic in nature. Vascular endothelial growth factor (VEGF), one of the key regulators of angiogenesis, is overexpressed in the pathogenesis of RA. VEGF expression is regulated by hypoxia-inducible factor-1{alpha} (HIF-1{alpha}), a master regulator of homeostasis which plays a pivotal role in hypoxia-induced angiogenesis. In this study we show that synthetic benzophenone analogue, 2-benzoyl-phenoxy acetamide (BP-1) can act as a novel anti-arthritic agent in an experimental adjuvant induced arthritis (AIA) rat model by targeting VEGF and HIF-1{alpha}. BP-1 administered hypoxic endothelial cells andmore » arthritic animals clearly showed down regulation of VEGF expression. Further, BP-1 inhibits nuclear translocation of HIF-1{alpha}, which in turn suppresses transcription of the VEGF gene. These results suggest a further possible clinical application of the BP-1 derivative as an anti-arthritic agent in association with conventional chemotherapeutic agents.« less

Therapeutic Evaluation of Mesenchymal Stem Cells in Chronic Gut Inflammation

DTIC Science & Technology

2014-09-01

AWARD NUMBER: W81XWH-11-1-0666 TITLE: Therapeutic Evaluation of Mesenchymal Stem Cells in Chronic Gut Inflammation PRINCIPAL INVESTIGATOR...2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Therapeutic Evaluation of Mesenchymal Stem Cells in Chronic Gut Inflammation 5b. GRANT NUMBER...several different mouse tissues during the development of chronic gut inflammation. 5. SUBJECT TERMS inflammatory bowel disease; mesenchymal stem

Lysyl Oxidase as a Serum Biomarker of Liver Fibrosis in Patients with Severe Obesity and Obstructive Sleep Apnea.

PubMed

Mesarwi, Omar A; Shin, Mi-Kyung; Drager, Luciano F; Bevans-Fonti, Shannon; Jun, Jonathan C; Putcha, Nirupama; Torbenson, Michael S; Pedrosa, Rodrigo P; Lorenzi-Filho, Geraldo; Steele, Kimberley E; Schweitzer, Michael A; Magnuson, Thomas H; Lidor, Anne O; Schwartz, Alan R; Polotsky, Vsevolod Y

2015-10-01

Obstructive sleep apnea (OSA) is associated with the progression of nonalcoholic fatty liver disease (NAFLD). We hypothesized that the hypoxia of OSA increases hepatic production of lysyl oxidase (LOX), an enzyme that cross-links collagen, and that LOX may serve as a biomarker of hepatic fibrosis. Thirty-five patients with severe obesity underwent liver biopsy, polysomnography, and serum LOX testing. A separate group with severe OSA had serum LOX measured before and after 3 mo of CPAP or no therapy, as did age-matched controls. LOX expression and secretion were measured in mouse hepatocytes following exposure to hypoxia. The Johns Hopkins Bayview Sleep Disorders Center, and the Hypertension Unit of the Heart Institute at the University of São Paulo Medical School. In the bariatric cohort, the apnea-hypopnea index was higher in patients with hepatic fibrosis than in those without fibrosis (42.7 ± 30.2 events/h, versus 16.2 ± 15.5 events/h; P = 0.002), as was serum LOX (84.64 ± 29.71 ng/mL, versus 45.46 ± 17.16 ng/mL; P < 0.001). In the sleep clinic sample, patients with severe OSA had higher baseline LOX than healthy controls (70.75 ng/mL versus 52.36 ng/mL, P = 0.046), and serum LOX decreased in patients with OSA on CPAP (mean decrease 20.49 ng/mL) but not in untreated patients (mean decrease 0.19 ng/mL). Hypoxic mouse hepatocytes demonstrated 5.9-fold increased LOX transcription (P = 0.046), and enhanced LOX protein secretion. The hypoxic stress of obstructive sleep apnea may increase circulating lysyl oxidase (LOX) levels. LOX may serve as a biomarker of liver fibrosis in patients with severe obesity and nonalcoholic fatty liver disease. © 2015 Associated Professional Sleep Societies, LLC.

COMPARATIVE GENOTOXIC RESPONSES TO ARSENITE IN GUINEA PIG, MOUSE, RAT AND HUMAN LYMPHOCYTES

EPA Science Inventory

Comparative genotoxic responses to arsenite in guinea pig, mouse, rat and human
lymphocytes.

Inorganic arsenic is a known human carcinogen causing skin, lung, and bladder cancer following chronic exposures. Yet, long-term laboratory animal carcinogenicity studies have ...

Maternal dietary creatine supplementation does not alter the capacity for creatine synthesis in the newborn spiny mouse.

PubMed

Dickinson, Hayley; Ireland, Zoe J; Larosa, Domenic A; O'Connell, Bree A; Ellery, Stacey; Snow, Rod; Walker, David W

2013-09-01

We have previously reported that maternal creatine supplementation protects the neonate from hypoxic injury. Here, we investigated whether maternal creatine supplementation altered expression of the creatine synthesis enzymes (arginine:glycine amidinotransferase [AGAT], guanidinoaceteate methyltransferase [GAMT]) and the creatine transporter (solute carrier family 6 [neurotransmitter transporter, creatine] member 8: SLC6A8) in the term offspring. Pregnant spiny mice were fed a 5% creatine monohydrate diet from midgestation (day 20) to term (39 days). Placentas and neonatal kidney, liver, heart, and brain collected at 24 hours of age underwent quantitative polymerase chain reaction and Western blot analysis. Maternal creatine had no effect on the expression of AGAT and GAMT in neonatal kidney and liver, but mRNA expression of AGAT in brain tissues was significantly decreased in both male and female neonates born to mothers who were fed the creatine diet. SLC6A8 expression was not affected by maternal dietary creatine loading in any tissues. Maternal dietary creatine supplementation from midgestation in the spiny mouse did not alter the capacity for creatine synthesis or transport.

Hypoxia-inducible Factor-2α-dependent Hypoxic Induction of Wnt10b Expression in Adipogenic Cells*

PubMed Central

Park, Young-Kwon; Park, Bongju; Lee, Seongyeol; Choi, Kang; Moon, Yunwon; Park, Hyunsung

2013-01-01

Adipocyte hyperplasia and hypertrophy in obesity can lead to many changes in adipose tissue, such as hypoxia, metabolic dysregulation, and enhanced secretion of cytokines. In this study, hypoxia increased the expression of Wnt10b in both human and mouse adipogenic cells, but not in hypoxia-inducible factor (HIF)-2α-deficient adipogenic cells. Chromatin immunoprecipitation analysis revealed that HIF-2α, but not HIF-1α, bound to the Wnt10b enhancer region as well as upstream of the Wnt1 gene, which is encoded by an antisense strand of the Wnt10b gene. Hypoxia-conditioned medium (H-CM) induced phosphorylation of lipoprotein-receptor-related protein 6 as well as β-catenin-dependent gene expression in normoxic cells, which suggests that H-CM contains canonical Wnt signals. Furthermore, adipogenesis of both human mesenchymal stem cells and mouse preadipocytes was inhibited by H-CM even under normoxic conditions. These results suggest that O2 concentration gradients influence the formation of Wnt ligand gradients, which are involved in the regulation of pluripotency, cell proliferation, and cell differentiation. PMID:23900840

Characterization of the expression of the pro-metastatic Mena(INV) isoform during breast tumor progression.

PubMed

Oudin, Madeleine J; Hughes, Shannon K; Rohani, Nazanin; Moufarrej, Mira N; Jones, Joan G; Condeelis, John S; Lauffenburger, Douglas A; Gertler, Frank B

2016-03-01

Several functionally distinct isoforms of the actin regulatory Mena are produced by alternative splicing during tumor progression. Forced expression of the Mena(INV) isoform drives invasion, intravasation and metastasis. However, the abundance and distribution of endogenously expressed Mena(INV) within primary tumors during progression remain unknown, as most studies to date have only assessed relative mRNA levels from dissociated tumor samples. We have developed a Mena(INV) isoform-specific monoclonal antibody and used it to examine Mena(INV) expression patterns in mouse mammary and human breast tumors. Mena(INV) expression increases during tumor progression and to examine the relationship between Mena(INV) expression and markers for epithelial or mesenchymal status, stemness, stromal cell types and hypoxic regions. Further, while Mena(INV) robustly expressed in vascularized areas of the tumor, it is not confined to cells adjacent to blood vessels. Altogether, these data demonstrate the specificity and utility of the anti-Mena(INV)-isoform specific antibody, and provide the first description of endogenous Mena(INV) protein expression in mouse and human tumors.

Acid-sensitive sheddable PEGylated, mannose-modified nanoparticles increase the delivery of betamethasone to chronic inflammation sites in a mouse model

PubMed Central

O’Mary, Hannah L.; Aldayel, Abdulaziz M.; Valdes, Solange A.; Naguib, Youssef W.; Li, Xu; Salvady, Karun; Cui, Zhengrong

2017-01-01

Inflammation is implicated in a host of chronic illnesses. Within these inflamed tissues, the pH of the microenvironment is decreased and immune cells, particularly macrophages, infiltrate the area. Additionally, the vascular integrity of these sites is altered with increased fenestrations between endothelial cells. These distinctive properties may be exploited to enhance targeted delivery of anti-inflammatory therapies. Using a mouse model of chronic inflammation, we previously showed that acid-sensitive sheddable PEGylation increases the distribution and retention of nanoparticles in chronic inflammation sites. Here we demonstrated that surface modification of the acid-sensitive sheddable PEGylated nanoparticles with mannose, a ligand to mannose receptors present in chronic inflammation sites, significantly increases the targeted delivery of the nanoparticles to these areas. Furthermore, we showed that the acid-sensitive sheddable PEGylated, mannose-modified nanoparticles are able to significantly increase the delivery of betamethasone-21-acetate (BA), a model anti-inflammatory compound, to chronic inflammation sites as compared to free BA. These results highlight the ability to engineer formulations to target chronic inflammation sites by exploiting the microenvironment of these regions. PMID:28463518

Characteristics and tolerances of the pocket mouse and incidence of disease. [CNS lesions during space flights

NASA Technical Reports Server (NTRS)

Lindberg, R. G.; Kraft, L. M.; Simmonds, R. C.; Bailey, O. T.; Dunlap, W. A.; Haymaker, W.

1975-01-01

Studies carried out on the pocket mouse colony on Apollo XVII are reported. They revealed no serological evidence of viral disease, no pathogenic enterobacteria or respiratory Mycoplasma on culture, a 25% incidence of sarcosporidiosis, and a 2% incidence of chronic meningitis or meningoencephalitis. It is concluded that the pocket mouse is a highly adaptive animal and very well-suited to space flight.

Decreased number and increased volume with mitochondrial enlargement of cerebellar synaptic terminals in a mouse model of chronic demyelination.

PubMed

Nguyen, Huy Bang; Sui, Yang; Thai, Truc Quynh; Ikenaka, Kazuhiro; Oda, Toshiyuki; Ohno, Nobuhiko

2018-05-23

Impaired nerve conduction, axonal degeneration, and synaptic alterations contribute to neurological disabilities in inflammatory demyelinating diseases. Cerebellar dysfunction is associated with demyelinating disorders, but the alterations of axon terminals in cerebellar gray matter during chronic demyelination are still unclear. We analyzed the morphological and ultrastructural changes of climbing fiber terminals in a mouse model of hereditary chronic demyelination. Three-dimensional ultrastructural analyses using serial block-face scanning electron microscopy and immunostaining for synaptic markers were performed in a demyelination mouse model caused by extra copies of myelin gene (PLP4e). At 1 month old, many myelinated axons were observed in PLP4e and wild-type mice, but demyelinated axons and axons with abnormally thin myelin were prominent in PLP4e mice at 5 months old. The density of climbing fiber terminals was significantly reduced in PLP4e mice at 5 months old. Reconstruction of climbing fiber terminals revealed that PLP4e climbing fibers had increased varicosity volume and enlarged mitochondria in the varicosities at 5-month-old mice. These results suggest that chronic demyelination is associated with alterations and loss of climbing fiber terminals in the cerebellar cortex, and that synaptic changes may contribute to cerebellar phenotypes observed in hereditary demyelinating disorders.

Quercetin, kaempferol and isorhamnetin in Elaeagnus pungens Thunb. leaf: pharmacological activities and quantitative determination studies.

PubMed

Zhu, Ji-Xiao; Wen, Le; Zhong, Wei-Jin; Xiong, Li; Liang, Jian; Wang, Hong-Ling

2018-05-26

Elaeagnus pungens (E. pungens) leaf was documented to be very effective to treat asthma and chronic bronchitis both as traditional Chinese medicine and minority traditional medicine; yet the actual effective components still remain unknown. This work is to investigate the anti-inflammatory, antalgic and antitussive activities of E. pungens leaf, quercetin and kaempferol, and their contents in E. pungens leaf. Pharmacological experiments showed they could considerably reduce ear-swelling of mouse and relieve writhing reaction of mouse; they could also prevent mouse from coughing, significantly. These findings suggested quercetin and kaempferol are major effective components treating asthma and chronic bronchitis. Quantitative analysis results indicated the levels of quercetin, kaempferol and isorhamnetin varied greatly in different species of Elaeagnus and in different plant parts: E. pungens leaf is more similar to Elaeagnus umbellate leaf chemically; quercetin level is exceptionally high in Elaeagnus oldhami leaf; E. pungens leaf is a better medical part for treating asthma and chronic bronchitis in comparison with other parts. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Dehydration as a Cause of Chronic Kidney Disease: Role of Fructokinase

DTIC Science & Technology

2015-10-01

required generating a mouse whose fructokinase gene is floxed (the floxed fructokinase mouse) and then selectively knocking fructokinase from the renal... sports drinks and rehydration packages for the hydration of individuals who are exposed to heat and dehydration. 5. CHANGES/PROBLEMS: Changes in

O2 consumption and heart rate in developing zebrafish (Danio rerio): influence of temperature and ambient O2.

PubMed

Barrionuevo, W R; Burggren, W W

1999-02-01

Body mass, length, oxygen consumption (MO2) and heart rate (fH) were measured in "embryos" (prior to hatching), "larvae" (days 10-20), "juveniles" (days 30-70 in 10-day intervals), and "adults" (day 100) of the zebrafish Danio rerio. Fish were chronically reared at either 25, 28, or 31 degreesC and then acutely exposed to hypoxia at different developmental stages. We hypothesized that at any given rearing and measurement temperature, D. rerio would maintain MO2 at lower ambient PO2 [i.e., have a lower critical partial pressure (Pcrit)] as development progressed and that at any given developmental stage individuals reared and measured at higher temperatures would show a more pronounced hypoxic bradycardia. MO2 in normoxic fish at 28 degreesC peaked at approximately 40 micromol. g-1. h-1 at day 10, thereafter falling to 4-5 micromol. g-1. h-1 at day 100. The Q10 for MO2 was 4-5 in embryos, falling to 2-3 from day 10 to day 60 and rising again to 4-5 at day 100. Pcrit at 28 degreesC was approximately 80 mmHg in embryos but decreased sharply to 20 mmHg at 100 days, supporting the hypothesis that more mature fish would be better able to oxygen regulate to lower ambient PO2 levels. Pcrit increased sharply with measurement temperature. Heart rate (fH) at 28 degreesC increased from about 125 beats/min in embryos to a peak of approximately 175 beats/min at days 10-30 and then fell to approximately 130 beats/min by day 100. Unlike for MO2, the Q10 for fH was more constant at 1.2-2.5 throughout development. Hypoxic exposure at any temperature had no effect on fH until approximately day 30, after which time a hypoxic bradycardia was evident. As evident for MO2, the bradycardia in older larvae was more profound at higher temperatures. On the assumption that bradycardia is indicative of hypoxic stress, the increasing prevalence of a hypoxic bradycardia in older, warmer individuals supports the hypothesis that increasing hypoxic susceptibility with development would be exacerbated by increasing temperature. Collectively, these data indicate that the ability to regulate MO2 and fH in response to the compounding demands of increased temperature and/or decreased oxygen availability first develops after approximately 20 days in D. rerio and, thereafter, the ability to maintain MO2 in the face of ambient hypoxia progressively builds through to adulthood. Additionally, the temperature responses of metabolism and heart rate differ substantially at different phases of development, suggesting a loose coupling between the respiratory and cardiovascular systems, at least early in development.

The effect of sulindac, a non-steroidal anti-inflammatory drug, attenuates inflammation and fibrosis in a mouse model of chronic pancreatitis

PubMed Central

2012-01-01

Background Chronic pancreatitis is characterized by progressive fibrosis, pain and loss of exocrine and endocrine functions. The long-standing chronic pancreatitis and its associated pancreatic fibrosis are the most common pathogenic events involved in human pancreatic carcinogenesis, but the therapeutic strategies to chronic pancreatitis and the chemoprevention of pancreatic carcinogenesis are very limited. Methods We investigated the effect of sulindac, a non-steroidal anti-inflammatory drug (NSAID), on inhibition of chronic pancreatitis in a caerulein induced chronic pancreatitis mouse model. Results Sulindac significantly reduced the severity of chronic pancreatitis including the extent of acini loss, inflammatory cell infiltration and stromal fibrosis. The protein expression of phosphorylation of MEK/ERK was inhibited in the chronic pancreatic tissues by sulindac treatment as measured by Western blot assay. The levels of inflammatory cytokines including TNF-α and MCP-1 were also significantly decreased with sulindac treatment, as well as the expression of TGF-β, PDGF-β, SHH and Gli in the chronic pancreatic tissue detected by qPCR assay and confirmed by western blot assay. The activation of pancreatic satellet cells was also inhibited by sulindac as measured by the activity of α-smooth muscle actin (α-SMA) in the pancreatic tissue of chronic pancreatitis. Conclusions Sulindac is a promising reagent for the treatment of chronic pancreatitis via inhibition of inflammatory cell infiltration and stromal fibrosis, the inhibitory effect of sulindac on chronic pancreatitis may through targeting the activation ERK/MAPK signaling pathway. PMID:22920325

Effects of Gestational and Postnatal Exposure to Chronic Intermittent Hypoxia on Diaphragm Muscle Contractile Function in the Rat

PubMed Central

McDonald, Fiona B.; Dempsey, Eugene M.; O'Halloran, Ken D.

2016-01-01

Alterations to the supply of oxygen during early life presents a profound stressor to physiological systems with aberrant remodeling that is often long-lasting. Chronic intermittent hypoxia (CIH) is a feature of apnea of prematurity, chronic lung disease, and sleep apnea. CIH affects respiratory control but there is a dearth of information concerning the effects of CIH on respiratory muscles, including the diaphragm—the major pump muscle of breathing. We investigated the effects of exposure to gestational CIH (gCIH) and postnatal CIH (pCIH) on diaphragm muscle function in male and female rats. CIH consisted of exposure in environmental chambers to 90 s of hypoxia reaching 5% O2 at nadir, once every 5 min, 8 h a day. Exposure to gCIH started within 24 h of identification of a copulation plug and continued until day 20 of gestation; animals were studied on postnatal day 22 or 42. For pCIH, pups were born in normoxia and within 24 h of delivery were exposed with dams to CIH for 3 weeks; animals were studied on postnatal day 22 or 42. Sham groups were exposed to normoxia in parallel. Following gas exposures, diaphragm muscle contractile, and endurance properties were examined ex vivo. Neither gCIH nor pCIH exposure had effects on diaphragm muscle force-generating capacity or endurance in either sex. Similarly, early life exposure to CIH did not affect muscle tolerance of severe hypoxic stress determined ex vivo. The findings contrast with our recent observation of upper airway dilator muscle weakness following exposure to pCIH. Thus, the present study suggests a relative resilience to hypoxic stress in diaphragm muscle. Co-ordinated activity of thoracic pump and upper airway dilator muscles is required for optimal control of upper airway caliber. A mismatch in the force-generating capacity of the complementary muscle groups could have adverse consequences for the control of airway patency and respiratory homeostasis. PMID:27462274

Kinase-dependent activation of voltage-gated Ca2+ channels by ET-1 in pulmonary arterial myocytes during chronic hypoxia.

PubMed

Luke, Trevor; Maylor, Julie; Undem, Clark; Sylvester, J T; Shimoda, Larissa A

2012-05-15

Exposure to chronic hypoxia (CH) causes pulmonary hypertension. The vasoconstrictor endothelin-1 (ET-1) is thought to play a role in the development of hypoxic pulmonary hypertension. In pulmonary arterial smooth muscle cells (PASMCs) from chronically hypoxic rats, ET-1 signaling is altered, with the ET-1-induced change in intracellular calcium concentration (Δ[Ca(2+)](i)) occurring through activation of voltage-dependent Ca(2+) channels (VDCC) even though ET-1-induced depolarization via inhibition of K(+) channels is lost. The mechanism underlying this response is unclear. We hypothesized that activation of VDCCs by ET-1 following CH might be mediated by protein kinase C (PKC) and/or Rho kinase, both of which have been shown to phosphorylate and activate VDCCs. To test this hypothesis, we examined the effects of PKC and Rho kinase inhibitors on the ET-1-induced Δ[Ca(2+)](i) in PASMCs from rats exposed to CH (10% O(2), 3 wk) using the Ca(2+)-sensitive dye fura 2-AM and fluorescent microscopy techniques. We found that staurosporine and GF109203X, inhibitors of PKC, and Y-27632 and HA 1077, Rho kinase inhibitors, reduced the ET-1-induced Δ[Ca(2+)](i) by >70%. Inhibition of tyrosine kinases (TKs) with genistein or tyrphostin A23, or combined inhibition of PKC, TKs, and Rho kinase, reduced the Δ[Ca(2+)](i) to a similar extent as inhibition of either PKC or Rho kinase alone. The ability of PKC or Rho kinase to activate VDCCs in our cells was verified using phorbol 12-myristate 13-acetate and GTP-γ-S. These results suggest that following CH, the ET-1-induced Δ[Ca(2+)](i) in PASMCs occurs via Ca(2+) influx through VDCCs mediated primarily by PKC, TKs, and Rho kinase.

Exosomes Secreted under Hypoxia Enhance Invasiveness and Stemness of Prostate Cancer Cells by Targeting Adherens Junction Molecules

PubMed Central

Ramteke, Anand; Ting, Harold; Agarwal, Chapla; Mateen, Samiha; Somasagara, Ranganathan; Hussain, Anowar; Graner, Michael; Frederick, Barbara; Agarwal, Rajesh; Deep, Gagan

2015-01-01

Hypoxic conditions in prostate cancer (PCA) are associated with poor prognosis; however, precise mechanism/s through which hypoxia promotes malignant phenotype remains unclear. Here, we analyzed the role of exosomes from hypoxic PCA cells in enhancing the invasiveness and stemness of naïve PCA cells, as well as in promoting cancer-associated fibroblast (CAF) phenotype in prostate stromal cells (PrSC). Human PCA LNCaP and PC3 cells were exposed to hypoxic (1% O2) or normoxic (21% O2) conditions, and exosomes secreted under hypoxic (ExoHypoxic) and normoxic (ExoNormoxic) conditions were isolated from conditioned media. Nanoparticle tracking analysis revealed that ExoHypoxic have smaller average size as compared to ExoNormoxic. Immunoblotting results showed a higher level of tetraspanins (CD63 and CD81), heat shock proteins (HSP90 and HSP70) and Annexin II in ExoHypoxic compared to ExoNormoxic. Co-culturing with ExoHypoxic increased the invasiveness and motility of naïve LNCaP and PC3 cells, respectively. ExoHypoxic also promoted prostasphere formation by both LNCaP and PC3 cells, and enhanced α-SMA (a CAF biomarker) expression in PrSC. Compared to ExoNormoxic, ExoHypoxic showed higher metalloproteinases activity and increased level of diverse signaling molecules (TGF-β2, TNF1α, IL6, TSG101, Akt, ILK1, and β-catenin). Furthermore, proteome analysis revealed a higher number of proteins in ExoHypoxic (160 proteins) compared to ExoNormoxic (62 proteins), primarily associated with the remodeling of epithelial adherens junction pathway. Importantly, ExoHypoxic targeted the expression of adherens junction proteins in naïve PC3 cells. These findings suggest that ExoHypoxic are loaded with unique proteins that could enhance invasiveness, stemness and induce microenvironment changes; thereby, promoting PCA aggressiveness. PMID:24347249

Satellite-based empirical models linking river plume dynamics with hypoxic area andvolume

EPA Science Inventory

Satellite-based empirical models explaining hypoxic area and volume variation were developed for the seasonally hypoxic (O2 < 2 mg L−1) northern Gulf of Mexico adjacent to the Mississippi River. Annual variations in midsummer hypoxic area and ...

Accelerating cine-MR Imaging in Mouse Hearts Using Compressed Sensing

PubMed Central

Wech, Tobias; Lemke, Angela; Medway, Debra; Stork, Lee-Anne; Lygate, Craig A; Neubauer, Stefan; Köstler, Herbert; Schneider, Jürgen E

2011-01-01

Purpose To combine global cardiac function imaging with compressed sensing (CS) in order to reduce scan time and to validate this technique in normal mouse hearts and in a murine model of chronic myocardial infarction. Materials and Methods To determine the maximally achievable acceleration factor, fully acquired cine data, obtained in sham and chronically infarcted (MI) mouse hearts were 2–4-fold undersampled retrospectively, followed by CS reconstruction and blinded image segmentation. Subsequently, dedicated CS sampling schemes were implemented at a preclinical 9.4 T magnetic resonance imaging (MRI) system, and 2- and 3-fold undersampled cine data were acquired in normal mouse hearts with high temporal and spatial resolution. Results The retrospective analysis demonstrated that an undersampling factor of three is feasible without impairing accuracy of cardiac functional parameters. Dedicated CS sampling schemes applied prospectively to normal mouse hearts yielded comparable left-ventricular functional parameters, and intra- and interobserver variability between fully and 3-fold undersampled data. Conclusion This study introduces and validates an alternative means to speed up experimental cine-MRI without the need for expensive hardware. J. Magn. Reson. Imaging 2011. © 2011 Wiley Periodicals, Inc. PMID:21932360

Differentiation of Mouse Induced Pluripotent Stem Cells (iPSCs) into Nucleus Pulposus-Like Cells In Vitro

PubMed Central

Chen, Jun; Lee, Esther J.; Jing, Liufang; Christoforou, Nicolas; Leong, Kam W.; Setton, Lori A.

2013-01-01

A large percentage of the population may be expected to experience painful symptoms or disability associated with intervertebral disc (IVD) degeneration – a condition characterized by diminished integrity of tissue components. Great interest exists in the use of autologous or allogeneic cells delivered to the degenerated IVD to promote matrix regeneration. Induced pluripotent stem cells (iPSCs), derived from a patient’s own somatic cells, have demonstrated their capacity to differentiate into various cell types although their potential to differentiate into an IVD cell has not yet been demonstrated. The overall objective of this study was to assess the possibility of generating iPSC-derived nucleus pulposus (NP) cells in a mouse model, a cell population that is entirely derived from notochord. This study employed magnetic activated cell sorting (MACS) to isolate a CD24+ iPSC subpopulation. Notochordal cell-related gene expression was analyzed in this CD24+ cell fraction via real time RT-PCR. CD24+ iPSCs were then cultured in a laminin-rich culture system for up to 28 days, and the mouse NP phenotype was assessed by immunostaining. This study also focused on producing a more conducive environment for NP differentiation of mouse iPSCs with addition of low oxygen tension and notochordal cell conditioned medium (NCCM) to the culture platform. iPSCs were evaluated for an ability to adopt an NP-like phenotype through a combination of immunostaining and biochemical assays. Results demonstrated that a CD24+ fraction of mouse iPSCs could be retrieved and differentiated into a population that could synthesize matrix components similar to that in native NP. Likewise, the addition of a hypoxic environment and NCCM induced a similar phenotypic result. In conclusion, this study suggests that mouse iPSCs have the potential to differentiate into NP-like cells and suggests the possibility that they may be used as a novel cell source for cellular therapy in the IVD. PMID:24086564

Atmospheric oxygen level affects growth trajectory, cardiopulmonary allometry and metabolic rate in the American alligator (Alligator mississippiensis)

PubMed Central

Owerkowicz, Tomasz; Elsey, Ruth M.; Hicks, James W.

2009-01-01

Summary Recent palaeoatmospheric models suggest large-scale fluctuations in ambient oxygen level over the past 550 million years. To better understand how global hypoxia and hyperoxia might have affected the growth and physiology of contemporary vertebrates, we incubated eggs and raised hatchlings of the American alligator. Crocodilians are one of few vertebrate taxa that survived these global changes with distinctly conservative morphology. We maintained animals at 30°C under chronic hypoxia (12% O2), normoxia (21% O2) or hyperoxia (30% O2). At hatching, hypoxic animals were significantly smaller than their normoxic and hyperoxic siblings. Over the course of 3 months, post-hatching growth was fastest under hyperoxia and slowest under hypoxia. Hypoxia, but not hyperoxia, caused distinct scaling of major visceral organs–reduction of liver mass, enlargement of the heart and accelerated growth of lungs. When absorptive and post-absorptive metabolic rates were measured in juvenile alligators, the increase in oxygen consumption rate due to digestion/absorption of food was greatest in hyperoxic alligators and smallest in hypoxic ones. Hyperoxic alligators exhibited the lowest breathing rate and highest oxygen consumption per breath. We suggest that, despite compensatory cardiopulmonary remodelling, growth of hypoxic alligators is constrained by low atmospheric oxygen supply, which may limit their food utilisation capacity. Conversely, the combination of elevated metabolism and low cost of breathing in hyperoxic alligators allows for a greater proportion of metabolised energy to be available for growth. This suggests that growth and metabolic patterns of extinct vertebrates would have been significantly affected by changes in the atmospheric oxygen level. PMID:19376944

Guinea Pig Oxygen-Sensing and Carotid Body Functional Properties

PubMed Central

Gonzalez-Obeso, Elvira; Docio, Inmaculada; Olea, Elena; Cogolludo, Angel; Obeso, Ana; Rocher, Asuncion; Gomez-Niño, Angela

2017-01-01

Mammals have developed different mechanisms to maintain oxygen supply to cells in response to hypoxia. One of those mechanisms, the carotid body (CB) chemoreceptors, is able to detect physiological hypoxia and generate homeostatic reflex responses, mainly ventilatory and cardiovascular. It has been reported that guinea pigs, originally from the Andes, have a reduced ventilatory response to hypoxia compared to other mammals, implying that CB are not completely functional, which has been related to genetically/epigenetically determined poor hypoxia-driven CB reflex. This study was performed to check the guinea pig CB response to hypoxia compared to the well-known rat hypoxic response. These experiments have explored ventilatory parameters breathing different gases mixtures, cardiovascular responses to acute hypoxia, in vitro CB response to hypoxia and other stimuli and isolated guinea pig chemoreceptor cells properties. Our findings show that guinea pigs are hypotensive and have lower arterial pO2 than rats, probably related to a low sympathetic tone and high hemoglobin affinity. Those characteristics could represent a higher tolerance to hypoxic environment than other rodents. We also find that although CB are hypo-functional not showing chronic hypoxia sensitization, a small percentage of isolated carotid body chemoreceptor cells contain tyrosine hydroxylase enzyme and voltage-dependent K+ currents and therefore can be depolarized. However hypoxia does not modify intracellular Ca2+ levels or catecholamine secretion. Guinea pigs are able to hyperventilate only in response to intense acute hypoxic stimulus, but hypercapnic response is similar to rats. Whether other brain areas are also activated by hypoxia in guinea pigs remains to be studied. PMID:28533756

Guinea Pig Oxygen-Sensing and Carotid Body Functional Properties.

PubMed

Gonzalez-Obeso, Elvira; Docio, Inmaculada; Olea, Elena; Cogolludo, Angel; Obeso, Ana; Rocher, Asuncion; Gomez-Niño, Angela

2017-01-01

Mammals have developed different mechanisms to maintain oxygen supply to cells in response to hypoxia. One of those mechanisms, the carotid body (CB) chemoreceptors, is able to detect physiological hypoxia and generate homeostatic reflex responses, mainly ventilatory and cardiovascular. It has been reported that guinea pigs, originally from the Andes, have a reduced ventilatory response to hypoxia compared to other mammals, implying that CB are not completely functional, which has been related to genetically/epigenetically determined poor hypoxia-driven CB reflex. This study was performed to check the guinea pig CB response to hypoxia compared to the well-known rat hypoxic response. These experiments have explored ventilatory parameters breathing different gases mixtures, cardiovascular responses to acute hypoxia, in vitro CB response to hypoxia and other stimuli and isolated guinea pig chemoreceptor cells properties. Our findings show that guinea pigs are hypotensive and have lower arterial pO 2 than rats, probably related to a low sympathetic tone and high hemoglobin affinity. Those characteristics could represent a higher tolerance to hypoxic environment than other rodents. We also find that although CB are hypo-functional not showing chronic hypoxia sensitization, a small percentage of isolated carotid body chemoreceptor cells contain tyrosine hydroxylase enzyme and voltage-dependent K + currents and therefore can be depolarized. However hypoxia does not modify intracellular Ca 2+ levels or catecholamine secretion. Guinea pigs are able to hyperventilate only in response to intense acute hypoxic stimulus, but hypercapnic response is similar to rats. Whether other brain areas are also activated by hypoxia in guinea pigs remains to be studied.

Chronic Mild Stress Assay Leading to Early Onset and Propagation of Alzheimer's Disease Phenotype in Mouse Models.

PubMed

Cuadrado-Tejedor, Mar; García-Osta, Ana

2016-01-01

A comprehensive chronic mild stress (CMS) procedure is presented, which consists in the application of unpredictable mild stressors to animal models in a random order for several weeks. This assay can be applied to Alzheimer's disease (AD) mouse models, leading to accelerated onset and increased severity of AD phenotypes and signs, including memory deficits and the accumulation of amyloid-β and phospho-tau. These assays open the way towards advanced studies on the influence of sustained mild stress, stress responses and pathways on the onset and propagation of Alzheimer's disease.

Determination of the Chronic Mammalian Toxicological Effects of TNT (twenty-Four Month Chronic Toxicity/Carcinogenicity Study of Trinitrotoluene (TNT) in the B6C3F1 Hybrid Mouse). Volume 1

DTIC Science & Technology

1984-12-01

chemistry parameters (see section l1.D.) Results of pretreatment health screen were within limits for the mice of this strain and age. Microbiological ...negative as measured by Microbiological Associates, Bethesda MD. Animals received 5002 rodent chow from arrival urtil their termina~lon, except during a...CARCINOGENICITY STUDY OF FRINITROTOLUENE IN THE B6C3FI MOUSE. ’EST DIET CONCENTRATION OF TNT TESI DOSE % % A x 100 - K!E!Th (mg,/kg/day) SEX INTENDED ANALYSED REL

Cardiac responses to hypoxia and reoxygenation in Drosophila.

PubMed

Zarndt, Rachel; Piloto, Sarah; Powell, Frank L; Haddad, Gabriel G; Bodmer, Rolf; Ocorr, Karen

2015-12-01

An adequate supply of oxygen is important for the survival of all tissues, but it is especially critical for tissues with high-energy demands, such as the heart. Insufficient tissue oxygenation occurs under a variety of conditions, including high altitude, embryonic and fetal development, inflammation, and thrombotic diseases, often affecting multiple organ systems. Responses and adaptations of the heart to hypoxia are of particular relevance in human cardiovascular and pulmonary diseases, in which the effects of hypoxic exposure can range in severity from transient to long-lasting. This study uses the genetic model system Drosophila to investigate cardiac responses to acute (30 min), sustained (18 h), and chronic (3 wk) hypoxia with reoxygenation. Whereas hearts from wild-type flies recovered quickly after acute hypoxia, exposure to sustained or chronic hypoxia significantly compromised heart function upon reoxygenation. Hearts from flies with mutations in sima, the Drosophila homolog of the hypoxia-inducible factor alpha subunit (HIF-α), exhibited exaggerated reductions in cardiac output in response to hypoxia. Heart function in hypoxia-selected flies, selected over many generations for survival in a low-oxygen environment, revealed reduced cardiac output in terms of decreased heart rate and fractional shortening compared with their normoxia controls. Hypoxia-selected flies also had smaller hearts, myofibrillar disorganization, and increased extracellular collagen deposition, consistent with the observed reductions in contractility. This study indicates that longer-duration hypoxic insults exert deleterious effects on heart function that are mediated, in part, by sima and advances Drosophila models for the genetic analysis of cardiac-specific responses to hypoxia and reoxygenation. Copyright © 2015 the American Physiological Society.

Carotid body potentiation during chronic intermittent hypoxia: implication for hypertension

PubMed Central

Del Rio, Rodrigo; Moya, Esteban A.; Iturriaga, Rodrigo

2014-01-01

Autonomic dysfunction is involved in the development of hypertension in humans with obstructive sleep apnea, and animals exposed to chronic intermittent hypoxia (CIH). It has been proposed that a crucial step in the development of the hypertension is the potentiation of the carotid body (CB) chemosensory responses to hypoxia, but the temporal progression of the CB chemosensory, autonomic and hypertensive changes induced by CIH are not known. We tested the hypothesis that CB potentiation precedes the autonomic imbalance and the hypertension in rats exposed to CIH. Thus, we studied the changes in CB chemosensory and ventilatory responsiveness to hypoxia, the spontaneous baroreflex sensitivity (BRS), heart rate variability (HRV) and arterial blood pressure in pentobarbital anesthetized rats exposed to CIH for 7, 14, and 21 days. After 7 days of CIH, CB chemosensory and ventilatory responses to hypoxia were enhanced, while BRS was significantly reduced by 2-fold in CIH-rats compared to sham-rats. These alterations persisted until 21 days of CIH. After 14 days, CIH shifted the HRV power spectra suggesting a predominance of sympathetic over parasympathetic tone. In contrast, hypertension was found after 21 days of CIH. Concomitant changes between the gain of spectral HRV, BRS, and ventilatory hypoxic chemoreflex showed that the CIH-induced BRS attenuation preceded the HRV changes. CIH induced a simultaneous decrease of the BRS gain along with an increase of the hypoxic ventilatory gain. Present results show that CIH-induced persistent hypertension was preceded by early changes in CB chemosensory control of cardiorespiratory and autonomic function. PMID:25429271

Age protects from harmful effects produced by chronic intermittent hypoxia.

PubMed

Quintero, M; Olea, E; Conde, S V; Obeso, A; Gallego-Martin, T; Gonzalez, C; Monserrat, J M; Gómez-Niño, A; Yubero, S; Agapito, T

2016-03-15

Obstructive sleep apnoea (OSA) affects an estimated 3–7% of the adult population, the frequency doubling at ages >60–65 years. As it evolves, OSA becomes frequently associated with cardiovascular, metabolic and neuropsychiatric pathologies defining OSA syndrome (OSAS). Exposing experimental animals to chronic intermittent hypoxia (CIH) can be used as a model of the recurrent hypoxic and O2 desaturation patterns observed in OSA patients. CIH is an important OSA event triggering associated pathologies; CIH induces carotid body (CB)-driven exaggerated sympathetic tone and overproduction of reactive oxygen species, related to the pathogenic mechanisms of associated pathologies observed in OSAS. Aiming to discover why OSAS is clinically less conspicuous in aged patients, the present study compares CIH effects in young (3–4 months) and aged (22–24 months) rats. To define potential distinctive patterns of these pathogenic mechanisms, mean arterial blood pressure as the final CIH outcome was measured. In young rats, CIH augmented CB sensory responses to hypoxia, decreased hypoxic ventilation and augmented sympathetic activity (plasma catecholamine levels and renal artery content and synthesis rate). An increased brainstem integration of CB sensory input as a trigger of sympathetic activity is suggested. CIH also caused an oxidative status decreasing aconitase/fumarase ratio and superoxide dismutase activity. In aged animals, CIH minimally affected CB responses, ventilation and sympathetic-related parameters leaving redox status unaltered. In young animals, CIH caused hypertension and in aged animals, whose baseline blood pressure was augmented, CIH did not augment it further. Plausible mechanisms of the differences and potential significance of these findings for the diagnosis and therapy of OSAS are discussed.

Bone Morphogenetic Protein (BMP)-3b Gene Depletion Causes High Mortality in a Mouse Model of Neonatal Hypoxic-Ischemic Encephalopathy.

PubMed

Ogawa, Yuko; Tsuji, Masahiro; Tanaka, Emi; Miyazato, Mikiya; Hino, Jun

2018-01-01

Bone morphogenetic proteins (BMPs) are a group of proteins that induce the formation of bone and the development of the nervous system. BMP-3b, also known as growth and differentiation factor 10, is a member of the BMPs that is highly expressed in the developing and adult brain. BMP-3b is therefore thought to play an important role in the brain even after physiological neurogenesis has completed. BMP-3b is induced in peri-infarct neurons in aged brains and is one of the most highly upregulated genes during the initiation of axonal sprouting. However, little is known about the role of BMP-3b in neonatal brain injury. In the present study, we aimed to describe the effects of BMP-3b gene depletion on neonatal hypoxic-ischemic encephalopathy, which frequently results in death or lifelong neurological disabilities, such as cerebral palsy and mental retardation. BMP-3b knockout and wild type mice were prepared at postnatal day 12. Mice of each genotype were divided into sham-surgery, mild hypoxia-ischemia (HI), and severe HI groups ( n = 12-45). Mice in the HI groups were subjected to left common carotid artery ligation followed by 30 min (mild HI) or 50 min (severe HI) of systemic hypoxic insult. A battery of tests, including behavioral tests, was performed, and the brain was then removed and evaluated at 14 days after insult. Compared with wild type pups, BMP-3b knockout pups demonstrated the following characteristics. (1) The males exposed to severe HI had a strikingly higher mortality rate, and as many as 70% of the knockout pups but none of the wild type pups died; (2) significantly more hyperactive locomotion was observed in males exposed to severe HI; and (3) significantly more hyperactive rearing was observed in both males and females exposed to mild HI. However, BMP-3b gene depletion did not affect other parameters, such as cerebral blood flow, cylinder test and rotarod test performance, body weight gain, brain weight, spleen weight, and neuroanatomical injury. The results of this study suggest that BMP-3b may play a crucial role to survive in severe neonatal hypoxic-ischemic insult.

[Mechanism of protective effects of tumor necrosis factor receptor associated protein 1 on hypoxic cardiomyocytes of rats].

PubMed

Xiang, F; Zhang, D X; Ma, S Y; Huang, Y S

2016-12-20

Objective: To investigate the mechanism of protective effects of tumor necrosis factor receptor associated protein 1 (TRAP1) on hypoxic cardiomyocytes of rats. Methods: Primary cultured cardiomyocytes were obtained from neonatal Sprague-Dawley rats (aged 1 to 3 days) and then used in the following experiments. (1) Cells were divided into group TRAP1 and control group according to the random number table (the same grouping method below), and then the total protein of cells was extracted. Total protein of cells in group TRAP1 was added with mouse anti-rat TRAP1 monoclonal antibody, while that in control group was added with the same type of IgG from mouse. Co-immunoprecipitation and protein mass spectrography analysis were used to determine the possible proteins interacted with TRAP1. (2) Cells were divided into normoxia blank control group (NBC), normoxia+ TRAP1 interference control group (NTIC), normoxia+ TRAP1 interference group (NTI), normoxia+ TRAP1 over-expression control group (NTOC), and normoxia+ TRAP1 over-expression group (NTO), with 1 well in each group. Cells in group NBC were routinely cultured, while cells in the latter four groups were respectively added with TRAP1 RNA interference empty virus vector, TRAP1 RNA interference adenovirus vector, TRAP1 over-expression empty virus vector, and TRAP1 over-expression adenovirus vector. Another batch of cells were divided into group NBC, hypoxic blank control group (HBC), hypoxic+ TRAP1 interference control group (HTIC), hypoxic+ TRAP1 interference group (HTI), hypoxic+ TRAP1 over-expression control group (HTOC), and hypoxic+ TRAP1 over-expression group (HTO), with 1 well in each group. Cells in hypoxic groups were under hypoxic condition for 6 hours after being treated as those in the corresponding normoxia groups, respectively. The mRNA expression of cytochrome c oxidase subunit Ⅱ (COXⅡ) of cells in each group was detected by real time fluorescent quantitive reverse transcription polymerase chain reaction. Experiments were repeated for three times. (3) Cells were divided into group NBC, group HBC, group HTOC, group HTO, hypoxic+ TRAP1 over-expression+ COXⅡinterference control group (HTOCIC), and hypoxic+ TRAP1 over-expression+ COXⅡinterference group (HTOCI), with 3 wells in each group. Cells in the previous 4 groups were treated as those in experiment (2). Cells in group HTOCIC and HTOCI were respectively transfected with COXⅡ RNA interference empty virus vector and COXⅡ RNA interference adenovirus vector, and then both added with TRAP1 over-expression adenovirus vector. The proliferation activity of cells was determined by cell counting kit 8 and microplate reader, and the ratio of death cells was measured by propidium lodide and Hoechst 33342 staining. Another batch of cells were divided into group NBC, group HBC, group HTIC, group HTI, hypoxic+ TRAP1 interference+ COXⅡover-expression control group (HTICOC), and hypoxic+ TRAP1 interference+ COXⅡ over-expression group (HTICO), with 3 wells in each group. Cells in the previous 4 groups were treated as those in experiment (2). Cells in group HTICOC and HTICO were both transfected with TRAP1 RNA interference adenovirus vector, and then respectively added with COXⅡ over-expression empty virus vector and COXⅡ over-expression adenovirus vector. The proliferation activity of cells and the ratio of death cells were detected as before. Experiments were repeated for three times. Data were processed with one-way analysis of variance and LSD test. Results: (1) The expression of TRAP1 was found in cells of group TRAP1, while that was not found in cells of control group. The possible proteins interacted with TRAP1 were keratin, COXⅡ, and an unknown protein with predicted molecular weight 13×10 3 . (2) Compared with that in group NBC, the mRNA expression of COXⅡof cells had no significant change in group NTIC and group NTOC (with P values above 0.05), but significantly decreased in group NTI ( P <0.01), and significantly increased in group NTO ( P <0.01). Compared with that in group NBC, the mRNA expression of COXⅡof cells in group HBC was significantly decreased ( P <0.01). Compared with that in group HBC, the mRNA expression of COXⅡof cells had no significant change in group HTIC and group HTOC (with P values above 0.05), but significantly decreased in group HTI ( P <0.01), and significantly increased in group HTO ( P <0.01). (3) The proliferation activity of cells in group NBC, group HBC, group HTOC, group HTO, group HTOCIC, and group HTOCI was respectively 0.498±0.022, 0.303±0.018, 0.313±0.032, 0.456±0.031, 0.448±0.034, and 0.335±0.026, and the ratios of death cells in above groups were respectively (4.7±1.5)%, (24.7±3.1)%, (26.0±2.7)%, (13.3±2.5)%, (12.7±2.1)%, and (21.0±1.7)%. Compared with those in group NBC, the proliferation activity of cells in HBC was decreased, while the ratio of death cells was increased (with P values below 0.01). Compared with those in group HBC, the proliferation activity of cells and the ratio of death cells in group HTOC had no significant change (with P values above 0.05), while the proliferation activity of cells was increased and the ratio of death cells was decreased in group HTO (with P values below 0.01). Compared with those in group HTO, the proliferation activity of cells and the ratio of death cells in group HTOCIC had no significant change (with P values above 0.05), while the proliferation activity of cells was decreased and the ratio of death cells was increased in group HTOCI (with P values below 0.01). (4) The proliferation activity of cells in group NBC, group HBC, group HTIC, group HTI, group HTICOC, and group HTICO was respectively 0.444±0.025, 0.275±0.016, 0.283±0.021, 0.150±0.009, 0.135±0.011, and 0.237±0.017, and the ratios of death cells in above groups were respectively (3.7±0.6)%, (21.0±2.7)%, (20.3±3.1)%, (31.7±2.5)%, (33.3±3.2)%, and (19.3±1.5)%. Compared with those in group HBC, the proliferation activity of cells and the ratio of death cells in group HTIC had no significant change (with P values above 0.05). Compared with those in group HBC and group HTIC, the proliferation activity of cells was decreased and the ratio of death cells was significantly increased in group HTI (with P values below 0.01). Compared with those in group HTI, the proliferation activity of cells and the ratio of death cells in group HTICOC had no significant change (with P values above 0.05), while the proliferation activity of cells was increased and the ratio of death cells was significantly decreased in group HTICO (with P values below 0.01). Conclusions: TRAP1 can up-regulate the expression of COXⅡ mRNA, and COXⅡ is one of the downstream effector molecules that TRAP1 mediates its protective effects on hypoxic cardiomyocytes.

3D culture of murine neural stem cells on decellularized mouse brain sections.

PubMed

De Waele, Jorrit; Reekmans, Kristien; Daans, Jasmijn; Goossens, Herman; Berneman, Zwi; Ponsaerts, Peter

2015-02-01

Transplantation of neural stem cells (NSC) in diseased or injured brain tissue is widely studied as a potential treatment for various neurological pathologies. However, effective cell replacement therapy relies on the intrinsic capacity of cellular grafts to overcome hypoxic and/or immunological barriers after transplantation. In this context, it is hypothesized that structural support for grafted NSC will be of utmost importance. With this study, we present a novel decellularization protocol for 1.5 mm thick mouse brain sections, resulting in the generation of acellular three-dimensional (3D) brain sections. Next, the obtained 3D brain sections were seeded with murine NSC expressing both the eGFP and luciferase reporter proteins (NSC-eGFP/Luc). Using real-time bioluminescence imaging, the survival and growth of seeded NSC-eGFP/Luc cells was longitudinally monitored for 1-7 weeks in culture, indicating the ability of the acellular brain sections to support sustained ex vivo growth of NSC. Next, the organization of a 3D maze-like cellular structure was examined using confocal microscopy. Moreover, under mitogenic stimuli (EGF and hFGF-2), most cells in this 3D culture retained their NSC phenotype. Concluding, we here present a novel protocol for decellularization of mouse brain sections, which subsequently support long-term 3D culture of undifferentiated NSC. Copyright © 2014 Elsevier Ltd. All rights reserved.

Brain oxygen tension controls the expansion of outer subventricular zone-like basal progenitors in the developing mouse brain.

PubMed

Wagenführ, Lisa; Meyer, Anne K; Braunschweig, Lena; Marrone, Lara; Storch, Alexander

2015-09-01

The mammalian neocortex shows a conserved six-layered structure that differs between species in the total number of cortical neurons produced owing to differences in the relative abundance of distinct progenitor populations. Recent studies have identified a new class of proliferative neurogenic cells in the outer subventricular zone (OSVZ) in gyrencephalic species such as primates and ferrets. Lissencephalic brains of mice possess fewer OSVZ-like progenitor cells and these do not constitute a distinct layer. Most in vitro and in vivo studies have shown that oxygen regulates the maintenance, proliferation and differentiation of neural progenitor cells. Here we dissect the effects of fetal brain oxygen tension on neural progenitor cell activity using a novel mouse model that allows oxygen tension to be controlled within the hypoxic microenvironment in the neurogenic niche of the fetal brain in vivo. Indeed, maternal oxygen treatment of 10%, 21% and 75% atmospheric oxygen tension for 48 h translates into robust changes in fetal brain oxygenation. Increased oxygen tension in fetal mouse forebrain in vivo leads to a marked expansion of a distinct proliferative cell population, basal to the SVZ. These cells constitute a novel neurogenic cell layer, similar to the OSVZ, and contribute to corticogenesis by heading for deeper cortical layers as a part of the cortical plate. © 2015. Published by The Company of Biologists Ltd.

A Battery of Motor Tests in a Neonatal Mouse Model of Cerebral Palsy.

PubMed

Feather-Schussler, Danielle N; Ferguson, Tanya S

2016-11-03

As the sheer number of transgenic mice strains grow and rodent models of pediatric disease increase, there is an expanding need for a comprehensive, standardized battery of neonatal mouse motor tests. These tests can validate injury or disease models, determine treatment efficacy and/or assess motor behaviors in new transgenic strains. This paper presents a series of neonatal motor tests to evaluate general motor function, including ambulation, hindlimb foot angle, surface righting, negative geotaxis, front- and hindlimb suspension, grasping reflex, four limb grip strength and cliff aversion. Mice between the ages of post-natal day 2 to 14 can be used. In addition, these tests can be used for a wide range of neurological and neuromuscular pathologies, including cerebral palsy, hypoxic-ischemic encephalopathy, traumatic brain injury, spinal cord injury, neurodegenerative diseases, and neuromuscular disorders. These tests can also be used to determine the effects of pharmacological agents, as well as other types of therapeutic interventions. In this paper, motor deficits were evaluated in a novel neonatal mouse model of cerebral palsy that combines hypoxia, ischemia and inflammation. Forty-eight hours after injury, five tests out of the nine showed significant motor deficits: ambulation, hindlimb angle, hindlimb suspension, four limb grip strength, and grasping reflex. These tests revealed weakness in the hindlimbs, as well as fine motor skills such as grasping, which are similar to the motor deficits seen in human cerebral palsy patients.

Optical imaging measurements of oxygen transport fluctuations and gradients in tumor microvascular networks

NASA Astrophysics Data System (ADS)

Sorg, Brian S.; Hardee, Matthew E.; Moeller, Benjamin J.; Dewhirst, Mark W.

2006-02-01

It is well established that hypoxia can influence tumor biology and physiology, gene expression, metastatic potential, treatment efficacy, and patient survival. Most human solid tumors have been shown to have some hypoxic regions, thus there is a strong motivation to understand the various causes of hypoxia. One key to understanding tumor hypoxia involves the study of oxygen transport to tumors, and the connection between hypoxia, tumor microvasculature, and the tumor microenvironment. Recent research has suggested that the causes of tumor hypoxia are much more complex than indicated by the classical paradigms ("chronic" and "acute" hypoxia), and several potential factors have been identified. Two such factors are temporal fluctuations in tissue pO II and longitudinal gradients in oxygen transport. Research has shown the existence of low frequency (<2 cycles per minute) fluctuations in tumor pO II without cessation of blood flow that can lead to transient hypoxia. In addition, longitudinal gradients in tumor pO II along the arteriolar afferent direction have been documented in window chamber tumors. However, the causes of the pO II temporal fluctuations and longitudinal gradients are not exactly known, and the clinical significance of these observations is not well understood. In this preliminary study, we demonstrate the potential of optical imaging measurements of hemoglobin saturation to add new information in these areas. Slow temporal fluctuations of hemoglobin saturation (HbSat) and gradients in the average HbSat were observed in some 4T1 mouse mammary carcinoma microvessels. With additional research, the mechanisms behind these phenomena and insights into their clinical significance may be revealed.

Uremic Toxins Affect the Imbalance of Redox State and Overexpression of Prolyl Hydroxylase 2 in Human Adipose Tissue-Derived Mesenchymal Stem Cells Involved in Wound Healing.

PubMed

Khanh, Vuong Cat; Ohneda, Kinuko; Kato, Toshiki; Yamashita, Toshiharu; Sato, Fujio; Tachi, Kana; Ohneda, Osamu

2017-07-01

Chronic kidney disease (CKD) results in a delay in wound healing because of its complications such as uremia, anemia, and fluid overload. Mesenchymal stem cells (MSCs) are considered to be a candidate for wound healing because of the ability to recruit many types of cells. However, it is still unclear whether the CKD-adipose tissue-derived MSCs (CKD-AT-MSCs) have the same function in wound healing as healthy donor-derived normal AT-MSCs (nAT-MSCs). In this study, we found that uremic toxins induced elevated reactive oxygen species (ROS) expression in nAT-MSCs, resulting in the reduced expression of hypoxia-inducible factor-1α (HIF-1α) under hypoxic conditions. Consistent with the uremic-treated AT-MSCs, there was a definite imbalance of redox state and high expression of ROS in CKD-AT-MSCs isolated from early-stage CKD patients. In addition, a transplantation study clearly revealed that nAT-MSCs promoted the recruitment of inflammatory cells and recovery from ischemia in the mouse flap model, whereas CKD-AT-MSCs had defective functions and the wound healing process was delayed. Of note, the expression of prolyl hydroxylase domain 2 (PHD2) is selectively increased in CKD-AT-MSCs and its inhibition can restore the expression of HIF-1α and the wound healing function of CKD-AT-MSCs. These results indicate that more studies about the functions of MSCs from CKD patients are required before they can be applied in the clinical setting.

[Autonomic regulation at emotional stress under hypoxic conditions in the elderly with physiological and accelerated aging: effect of hypoxic training].

PubMed

Os'mak, E D; Asanov, É O

2014-01-01

The effect of hypoxic training on autonomic regulation in psycho-emotional stress conditions in hypoxic conditions in older people with physiological (25 people) and accelerated (28 people) aging respiratory system. It is shown that hypoxic training leads to an increase in vagal activity indicators (HF) and reduced simpatovagal index (LF/HF), have a normalizing effect on the autonomic balance during stress loads in older people with different types of aging respiratory system.

[3H]-nitrendipine binding in membranes obtained from hypoxic and reoxygenated heart.

PubMed

Matucci, R; Bennardini, F; Sciammarella, M L; Baccaro, C; Stendardi, I; Franconi, F; Giotti, A

1987-04-01

We compared the binding properties of [3H]-nitrendipine in heart membranes from normal guinea-pig heart and from hypoxic or hypoxic and reoxygenated heart. The [3H]-nitrendipine binds a single class of high capacity (Bmax 667.2 +/- 105.2) with high affinity (KD 0.14 +/- 0.02) binding sites. By contrast, in membranes of hypoxic and reoxygenated heart the Bmax decreases significantly while it remains unaffected during hypoxia. Xanthinoxidase activity is increased in hypoxic-reoxygenated hearts.

Effect of Delta-9-tetrahydrocannabinol on mouse resistance to systemic Candida albicans infection.

PubMed

Blumstein, Gideon W; Parsa, Arya; Park, Anthony K; McDowell, Beverly L P; Arroyo-Mendoza, Melissa; Girguis, Marie; Adler-Moore, Jill P; Olson, Jon; Buckley, Nancy E

2014-01-01

Delta-9-tetrahydrocannabinol (Δ9-THC), the psychoactive component of marijuana, is known to suppress the immune responses to bacterial, viral and protozoan infections, but its effects on fungal infections have not been studied. Therefore, we investigated the effects of chronic Δ9-THC treatment on mouse resistance to systemic Candida albicans (C. albicans) infection. To determine the outcome of chronic Δ9-THC treatment on primary, acute systemic candidiasis, c57BL/6 mice were given vehicle or Δ9-THC (16 mg/kg) in vehicle on days 1-4, 8-11 and 15-18. On day 19, mice were infected with 5×10(5) C. albicans. We also determined the effect of chronic Δ9-THC (4-64 mg/kg) treatment on mice infected with a non-lethal dose of 7.5×10(4) C. albicans on day 2, followed by a higher challenge with 5×10(5) C. albicans on day 19. Mouse resistance to the infection was assessed by survival and tissue fungal load. Serum cytokine levels were determine to evaluate the immune responses. In the acute infection, chronic Δ9-THC treatment had no effect on mouse survival or tissue fungal load when compared to vehicle treated mice. However, Δ9-THC significantly suppressed IL-12p70 and IL-12p40 as well as marginally suppressed IL-17 versus vehicle treated mice. In comparison, when mice were given a secondary yeast infection, Δ9-THC significantly decreased survival, increased tissue fungal burden and suppressed serum IFN-γ and IL-12p40 levels compared to vehicle treated mice. The data showed that chronic Δ9-THC treatment decreased the efficacy of the memory immune response to candida infection, which correlated with a decrease in IFN-γ that was only observed after the secondary candida challenge.

Clinical and diagnostic features of delayed hypoxic leukoencephalopathy.

PubMed

Shprecher, David R; Flanigan, Kevin M; Smith, A Gordon; Smith, Shawn M; Schenkenberg, Thomas; Steffens, John

2008-01-01

Delayed hypoxic leukoencephalopathy is an underrecognized syndrome of delayed demyelination, which is important to consider when delayed onset of neuropsychiatric symptoms follows a hypoxic event. The authors describe clinical and diagnostic features of three such cases, review the pathophysiology of delayed hypoxic leukoencephalopathy, and discuss features which may help distinguish it from toxic leukoencephalopathy.

Neuroprotective Role of Exogenous Brain-Derived Neurotrophic Factor in Hypoxia-Hypoglycemia-Induced Hippocampal Neuron Injury via Regulating Trkb/MiR134 Signaling.

PubMed

Huang, Weidong; Meng, Facai; Cao, Jie; Liu, Xiaobin; Zhang, Jie; Li, Min

2017-05-01

Hypoxic-ischemic brain injury is an important cause of neonatal mortality and morbidity. Brain-derived neurotrophic factor (BDNF) has been reported to play a neuroprotective role in hypoxic-ischemic brain injury; however, the specific effects and mechanism of BDNF on hypoxic-hypoglycemic hippocampal neuron injury remains unknown. The current study investigated the action of BDNF in regulating cerebral hypoxic-ischemic injury by simulating hippocampal neuron ischemia and hypoxia. We found that BDNF, p-Trkb, and miR-134 expression levels decreased, and that exogenous BDNF increased survival and reduced apoptosis in hypoxic-hypoglycemic hippocampal neurons. The results also show that BDNF inhibits MiR-134 expression by activating the TrkB pathway. Transfection with TrkB siRNA and pre-miR-134 abrogated the neuroprotective role of BDNF in hypoxic-hypoglycemic hippocampal neurons. Our results suggest that exogenous BDNF alleviates hypoxic-ischemic brain injury through the Trkb/MiR-134 pathway. These findings may help to identify a potential therapeutic agent for the treatment of hypoxic-ischemic brain injury.

Cytokine and Chemokine Expression in Kidneys during Chronic Leptospirosis in Reservoir and Susceptible Animal Models

PubMed Central

Matsui, Mariko; Roche, Louise; Geroult, Sophie; Soupé-Gilbert, Marie-Estelle; Monchy, Didier; Huerre, Michel; Goarant, Cyrille

2016-01-01

Leptospirosis is caused by pathogenic spirochetes of the genus Leptospira. Humans can be infected after exposure to contaminated urine of reservoir animals, usually rodents, regarded as typical asymptomatic carriers of leptospires. In contrast, accidental hosts may present an acute form of leptospirosis with a range of clinical symptoms including the development of Acute Kidney Injury (AKI). Chronic Kidney Disease (CKD) is considered as a possible AKI-residual sequela but little is known about the renal pathophysiology consequent to leptospirosis infection. Herein, we studied the renal morphological alterations in relation with the regulation of inflammatory cytokines and chemokines, comparing two experimental models of chronic leptospirosis, the golden Syrian hamster that survived the infection, becoming carrier of virulent leptospires, and the OF1 mouse, a usual reservoir of the bacteria. Animals were monitored until 28 days after injection with a virulent L. borgpetersenii serogroup Ballum to assess chronic infection. Hamsters developed morphological alterations in the kidneys with tubulointerstitial nephritis and fibrosis. Grading of lesions revealed higher scores in hamsters compared to the slight alterations observed in the mouse kidneys, irrespective of the bacterial load. Interestingly, pro-fibrotic TGF-β was downregulated in mouse kidneys. Moreover, cytokines IL-1β and IL-10, and chemokines MIP-1α/CCL3 and IP-10/CXCL-10 were significantly upregulated in hamster kidneys compared to mice. These results suggest a possible maintenance of inflammatory processes in the hamster kidneys with the infiltration of inflammatory cells in response to bacterial carriage, resulting in alterations of renal tissues. In contrast, lower expression levels in mouse kidneys indicated a better regulation of the inflammatory response and possible resolution processes likely related to resistance mechanisms. PMID:27219334

Chronic Anatabine Treatment Reduces Alzheimer's Disease (AD)-Like Pathology and Improves Socio-Behavioral Deficits in a Transgenic Mouse Model of AD.

PubMed

Verma, Megha; Beaulieu-Abdelahad, David; Ait-Ghezala, Ghania; Li, Rena; Crawford, Fiona; Mullan, Michael; Paris, Daniel

2015-01-01

Anatabine is a minor tobacco alkaloid, which is also found in plants of the Solanaceae family and displays a chemical structure similarity with nicotine. We have shown previously that anatabine displays some anti-inflammatory properties and reduces microgliosis and tau phosphorylation in a pure mouse model of tauopathy. We therefore investigated the effects of a chronic oral treatment with anatabine in a transgenic mouse model (Tg PS1/APPswe) of Alzheimer's disease (AD) which displays pathological Aβ deposits, neuroinflammation and behavioral deficits. In the elevated plus maze, Tg PS1/APPswe mice exhibited hyperactivity and disinhibition compared to wild-type mice. Six and a half months of chronic oral anatabine treatment, suppressed hyperactivity and disinhibition in Tg PS1/APPswe mice compared to Tg PS1/APPswe receiving regular drinking water. Tg PS1/APPswe mice also elicited profound social interaction and social memory deficits, which were both alleviated by the anatabine treatment. We found that anatabine reduces the activation of STAT3 and NFκB in the vicinity of Aβ deposits in Tg PS1/APPswe mice resulting in a reduction of the expression of some of their target genes including Bace1, iNOS and Cox-2. In addition, a significant reduction in microgliosis and pathological deposition of Aβ was observed in the brain of Tg PS1/APPswe mice treated with anatabine. This is the first study to investigate the impact of chronic anatabine treatment on AD-like pathology and behavior in a transgenic mouse model of AD. Overall, our data show that anatabine reduces β-amyloidosis, neuroinflammation and alleviates some behavioral deficits in Tg PS1/APPswe, supporting further exploration of anatabine as a possible disease modifying agent for the treatment of AD.

Hypoxic tumor-derived microvesicles negatively regulate NK cell function by a mechanism involving TGF-β and miR23a transfer.

PubMed

Berchem, Guy; Noman, Muhammad Zaeem; Bosseler, Manon; Paggetti, Jerome; Baconnais, Sonia; Le Cam, Eric; Nanbakhsh, Arash; Moussay, Etienne; Mami-Chouaib, Fathia; Janji, Bassam; Chouaib, Salem

2016-04-01

Tumor-derived microvesicles (TD-MVs) are key mediators which are shed by cancer cells and can sensitize neighboring cells in the tumor microenvironment. TD-MVs are extracellular vesicles composed of exosomes and MVs and promote cancer invasion and metastasis. Intratumoral hypoxia is an integral component of all solid tumors. The relationship between hypoxic tumor-shed MVs and NK-mediated cytotoxicity remains unknown. In this paper, we reported that MVs derived from hypoxic tumor cells qualitatively differ from those derived from normoxic tumor cells. Using multiple tumor models, we showed that hypoxic MVs inhibit more NK cell function as compared to normoxic MVs. Hypoxic TD-MVs package two immunosuppressive factors involved in the impairment of natural killer (NK) cell cytotoxicity against different tumor cells in vitro and in vivo . We showed that following their uptake by NK cells, hypoxic TD-MVs transfer TGF-β1 to NK cells, decreasing the cell surface expression of the activating receptor NKG2D, thereby inhibiting NK cell function. MicroRNA profiling revealed the presence of high levels of miR-210 and miR-23a in hypoxic TD-MVs. We demonstrated that miR-23a in hypoxic TD-MVs operates as an additional immunomosuppressive factor, since it directly targets the expression of CD107a in NK cells. To our knowledge, this is the first study to show that hypoxic tumor cells by secreting MVs can educate NK cells and decrease their antitumor immune response. This study highlights the existence of a novel mechanism of immune suppression mediated by hypoxic TD-MVs and further improves our understanding of the immunosuppressive mechanisms prevailing in the hypoxic tumor microenvironment.

The hTERT Promoter Enhances the Antitumor Activity of an Oncolytic Adenovirus under a Hypoxic Microenvironment

PubMed Central

Hashimoto, Yuuri; Tazawa, Hiroshi; Teraishi, Fuminori; Kojima, Toru; Watanabe, Yuichi; Uno, Futoshi; Yano, Shuya; Urata, Yasuo; Kagawa, Shunsuke; Fujiwara, Toshiyoshi

2012-01-01

Hypoxia is a microenvironmental factor that contributes to the invasion, progression and metastasis of tumor cells. Hypoxic tumor cells often show more resistance to conventional chemoradiotherapy than normoxic tumor cells, suggesting the requirement of novel antitumor therapies to efficiently eliminate the hypoxic tumor cells. We previously generated a tumor-specific replication-competent oncolytic adenovirus (OBP-301: Telomelysin), in which the human telomerase reverse transcriptase (hTERT) promoter drives viral E1 expression. Since the promoter activity of the hTERT gene has been shown to be upregulated by hypoxia, we hypothesized that, under hypoxic conditions, the antitumor effect of OBP-301 with the hTERT promoter would be more efficient than that of the wild-type adenovirus 5 (Ad5). In this study, we investigated the antitumor effects of OBP-301 and Ad5 against human cancer cells under a normoxic (20% oxygen) or a hypoxic (1% oxygen) condition. Hypoxic condition induced nuclear accumulation of the hypoxia-inducible factor-1α and upregulation of hTERT promoter activity in human cancer cells. The cytopathic activity of OBP-301 was significantly higher than that of Ad5 under hypoxic condition. Consistent with their cytopathic activity, the replication of OBP-301 was significantly higher than that of Ad5 under the hypoxic condition. OBP-301-mediated E1A was expressed within hypoxic areas of human xenograft tumors in mice. These results suggest that the cytopathic activity of OBP-301 against hypoxic tumor cells is mediated through hypoxia-mediated activation of the hTERT promoter. Regulation of oncolytic adenoviruses by the hTERT promoter is a promising antitumor strategy, not only for induction of tumor-specific oncolysis, but also for efficient elimination of hypoxic tumor cells. PMID:22720091

Apoptosis, energy metabolism, and fraction of radiobiologically hypoxic cells: a study of human melanoma multicellular spheroids.

PubMed

Rofstad, E K; Eide, K; Skøyum, R; Hystad, M E; Lyng, H

1996-09-01

The magnitude of the fraction of radiobiologically hypoxic cells in tumours is generally believed to reflect the efficiency of the vascular network. Theoretical studies have suggested that the hypoxic fraction might also be influenced by biological properties of the tumour cells. Quantitative experimental results of cell energy metabolism, hypoxia- induced apoptosis, and radiobiological hypoxia are reported here. Human melanoma multicellular spheroids (BEX-c and WIX-c) were used as tumour models to avoid confounding effects of the vascular network. Radiobiological studies showed that the fractions of hypoxic cells in 1000-microM spheroids were 32 +/- 12% (BEX-c) and 2.5 +/- 1.1% (WIX-c). The spheroid hypoxic volume fractions (28 +/- 6% (BEX-c) and 1.4 +/- 7% (WIX-c)), calculated from the rate of oxygen consumption per cell, the cell packing density, and the thickness of the viable rim, were similar to the fractions of radiobiologically hypoxic cells. Large differences between tumours in fraction of hypoxic cells are therefore not necessarily a result of differences in the efficiency of the vascular network. Studies of monolayer cell cultures, performed to identify the biological properties of the BEX-c and WIX-c cells leading to this large difference in fraction of hypoxic cells, gave the following results: (1) WIX-c showed lower cell surviving fractions after exposure to hypoxia than BEX-c, (2) WIX-c showed higher glucose uptake and lactate release rates than BEX-c both under aerobic and hypoxic conditions, and (3) hypoxia induced apoptosis in WIX-c but not in BEX-c. These observations suggested that the difference between BEX-c and WIX-c spheroids in fraction of hypoxic cells resulted partly from differences in cell energy metabolism and partly from a difference in capacity to retain viability under hypoxic stress. The induction of apoptosis by hypoxia was identified as a phenomenon which has an important influence on the magnitude of the fraction of radiobiologically hypoxic cells in multicellular spheroids.

Destruction of a distal hypoxia response element abolishes trans-activation of the PAG1 gene mediated by HIF-independent chromatin looping

PubMed Central

Schörg, Alexandra; Santambrogio, Sara; Platt, James L.; Schödel, Johannes; Lindenmeyer, Maja T.; Cohen, Clemens D.; Schrödter, Katrin; Mole, David R.; Wenger, Roland H.; Hoogewijs, David

2015-01-01

A crucial step in the cellular adaptation to oxygen deficiency is the binding of hypoxia-inducible factors (HIFs) to hypoxia response elements (HREs) of oxygen-regulated genes. Genome-wide HIF-1α/2α/β DNA-binding studies revealed that the majority of HREs reside distant to the promoter regions, but the function of these distal HREs has only been marginally studied in the genomic context. We used chromatin immunoprecipitation (ChIP), gene editing (TALEN) and chromosome conformation capture (3C) to localize and functionally characterize a 82 kb upstream HRE that solely drives oxygen-regulated expression of the newly identified HIF target gene PAG1. PAG1, a transmembrane adaptor protein involved in Src signalling, was hypoxically induced in various cell lines and mouse tissues. ChIP and reporter gene assays demonstrated that the −82 kb HRE regulates PAG1, but not an equally distant gene further upstream, by direct interaction with HIF. Ablation of the consensus HRE motif abolished the hypoxic induction of PAG1 but not general oxygen signalling. 3C assays revealed that the −82 kb HRE physically associates with the PAG1 promoter region, independent of HIF-DNA interaction. These results demonstrate a constitutive interaction between the −82 kb HRE and the PAG1 promoter, suggesting a physiologically important rapid response to hypoxia. PMID:26007655

Neuroprotection by selective neuronal deletion of Atg7 in neonatal brain injury

PubMed Central

Xie, Cuicui; Ginet, Vanessa; Sun, Yanyan; Koike, Masato; Zhou, Kai; Li, Tao; Li, Hongfu; Li, Qian; Wang, Xiaoyang; Uchiyama, Yasuo; Truttmann, Anita C.; Kroemer, Guido; Puyal, Julien; Blomgren, Klas; Zhu, Changlian

2016-01-01

ABSTRACT Perinatal asphyxia induces neuronal cell death and brain injury, and is often associated with irreversible neurological deficits in children. There is an urgent need to elucidate the neuronal death mechanisms occurring after neonatal hypoxia-ischemia (HI). We here investigated the selective neuronal deletion of the Atg7 (autophagy related 7) gene on neuronal cell death and brain injury in a mouse model of severe neonatal hypoxia-ischemia. Neuronal deletion of Atg7 prevented HI-induced autophagy, resulted in 42% decrease of tissue loss compared to wild-type mice after the insult, and reduced cell death in multiple brain regions, including apoptosis, as shown by decreased caspase-dependent and -independent cell death. Moreover, we investigated the lentiform nucleus of human newborns who died after severe perinatal asphyxia and found increased neuronal autophagy after severe hypoxic-ischemic encephalopathy compared to control uninjured brains, as indicated by the numbers of MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3)-, LAMP1 (lysosomal-associated membrane protein 1)-, and CTSD (cathepsin D)-positive cells. These findings reveal that selective neuronal deletion of Atg7 is strongly protective against neuronal death and overall brain injury occurring after HI and suggest that inhibition of HI-enhanced autophagy should be considered as a potential therapeutic target for the treatment of human newborns developing severe hypoxic-ischemic encephalopathy. PMID:26727396

Real-time optoacoustic monitoring of stroke

NASA Astrophysics Data System (ADS)

Kneipp, Moritz; Turner, Jake; Hambauer, Sebastian; Krieg, Sandro M.; Lehmberg, Jens; Lindauer, Ute; Razansky, Daniel

2014-03-01

Characterizing disease progression and identifying possible therapeutic interventions in stroke is greatly aided by the use of longitudinal function imaging studies. In this study, we investigate the applicability of real-time multispectral optoacoustic tomography (MSOT) as a tool for non-invasive monitoring of the progression of stroke in the whole brain. The middle cerebral artery occlusion (MCAO) method was used to induce stroke. Mice were imaged under isoflurane anesthesia preoperatively and at several time points during and after the 60-minute occlusion. The animals were sacrificed after 24 hours and their excised brains frozen at -80°C for sectioning. The cryosection were stained using H&E staining to identify the ischemic lesion. Major vessels are readily identifiable in the whole mouse head in the in vivo optoacoustic scans. During ischemia, a reduction in cerebral blood volume is detectable in the cortex. Post ischemia, spectral unmixing of the optoacoustic signals shows an asymmetry of the deoxygenated hemoglobin in the hemisphere affected by MCAO. This hypoxic area was mainly located around the boundary of the ischemic lesion and was therefore identified as the ischemic penumbra. Non-invasive functional MSOT imaging is able to visualize the hypoxic penumbra in brains affected by stroke. Stopping the spread of the infarct area and revitalizing the penumbra is central in stroke research, this new imaging technique may therefore prove to be a valuable tool in the monitoring and developing new treatments.

Preinduction of HSP70 promotes hypoxic tolerance and facilitates acclimatization to acute hypobaric hypoxia in mouse brain

PubMed Central

Zhang, Kuan; Zhao, Tong; Huang, Xin; Liu, Zhao-hui; Xiong, Lei; Li, Ming-ming; Wu, Li-ying; Zhao, Yong-qi

2008-01-01

It has been shown that induction of HSP70 by administration of geranylgeranylacetone (GGA) leads to protection against ischemia/reperfusion injury. The present study was performed to determine the effect of GGA on the survival of mice and on brain damage under acute hypobaric hypoxia. The data showed that the mice injected with GGA survived significantly longer than control animals (survival time of 9.55 ± 3.12 min, n = 16 vs. controls at 4.28 ± 4.29 min, n = 15, P < 0.005). Accordingly, the cellular necrosis or degeneration of the hippocampus and the cortex induced by sublethal hypoxia for 6 h could be attenuated by preinjection with GGA, especially in the CA2 and CA3 regions of the hippocampus. In addition, the activity of nitric oxide synthase (NOS) of the hippocampus and the cortex was increased after exposure to sublethal hypoxia for 6 h but could be inhibited by the preinjection of GGA. Furthermore, the expression of HSP70 was significantly increased at 1 h after GGA injection. These results suggest that administration of GGA improved survival rate and prevented acute hypoxic damage to the brain and that the underlying mechanism involved induction of HSP70 and inhibition of NOS activity. PMID:19105051

Growth Factor-Reinforced ECM Fabricated from Chemically Hypoxic MSC Sheet with Improved In Vivo Wound Repair Activity.

PubMed

Du, Hui-Cong; Jiang, Lin; Geng, Wen-Xin; Li, Jing; Zhang, Rui; Dang, Jin-Ge; Shu, Mao-Guo; Li, Li-Wen

2017-01-01

MSC treatment can promote cutaneous wound repair through multiple mechanisms, and paracrine mediators secreted by MSC are responsible for most of its therapeutic benefits. Recently, MSC sheet composed of live MSCs and their secreted ECMs was reported to promote wound healing; however, whether its ECM alone could accelerate wound closure remained unknown. In this study, Nc-ECM and Cc-ECM were prepared from nonconditioned and CoCl 2 -conditioned MSC sheets, respectively, and their wound healing properties were evaluated in a mouse model of full-thickness skin defect. Our results showed that Nc-ECM can significantly promote wound repair through early adipocyte recruitment, rapid reepithelialization, enhanced granulation tissue growth, and augmented angiogenesis. Moreover, conditioning of MSC sheet with CoCl 2 dramatically enriched its ECM with collagen I, collagen III, TGF- β 1, VEGF, and bFGF via activation of HIF-1 α and hence remarkably improved its ECM's in vivo wound healing potency. All the Cc-ECM-treated wounds completely healed on day 7, while Nc-ECM-treated wounds healed about 85.0% ± 8.6%, and no-treatment wounds only healed 69.8% ± 9.6% ( p < 0.05). Therefore, we believe that such growth factor-reinforced ECM fabricated from chemically hypoxic MSC sheet has the potential for clinical translation and will lead to a MSC-derived, cost-effective, bankable biomaterial for wound management.

Propiconazole increases reactive oxygen species levels in mouse hepatic cells in culture and in mouse liver by a cytochrome P450 enzyme mediated process

EPA Science Inventory

Propiconazole induces hepatocarcinomas and hepatoadenomas in mice and is a rat liver tumor promoter. Transcriptional, proteomic, metabolomic and biochemical studies of hepatic tissues from mice treated with propiconazole under the conditions of the chronic bioassay indicate that ...

A novel flexible cuff-like microelectrode for dual purpose, acute and chronic electrical interfacing with the mouse cervical vagus nerve

NASA Astrophysics Data System (ADS)

Caravaca, A. S.; Tsaava, T.; Goldman, L.; Silverman, H.; Riggott, G.; Chavan, S. S.; Bouton, C.; Tracey, K. J.; Desimone, R.; Boyden, E. S.; Sohal, H. S.; Olofsson, P. S.

2017-12-01

Objective. Neural reflexes regulate immune responses and homeostasis. Advances in bioelectronic medicine indicate that electrical stimulation of the vagus nerve can be used to treat inflammatory disease, yet the understanding of neural signals that regulate inflammation is incomplete. Current interfaces with the vagus nerve do not permit effective chronic stimulation or recording in mouse models, which is vital to studying the molecular and neurophysiological mechanisms that control inflammation homeostasis in health and disease. We developed an implantable, dual purpose, multi-channel, flexible ‘microelectrode’ array, for recording and stimulation of the mouse vagus nerve. Approach. The array was microfabricated on an 8 µm layer of highly biocompatible parylene configured with 16 sites. The microelectrode was evaluated by studying the recording and stimulation performance. Mice were chronically implanted with devices for up to 12 weeks. Main results. Using the microelectrode in vivo, high fidelity signals were recorded during physiological challenges (e.g potassium chloride and interleukin-1β), and electrical stimulation of the vagus nerve produced the expected significant reduction of blood levels of tumor necrosis factor (TNF) in endotoxemia. Inflammatory cell infiltration at the microelectrode 12 weeks of implantation was limited according to radial distribution analysis of inflammatory cells. Significance. This novel device provides an important step towards a viable chronic interface for cervical vagus nerve stimulation and recording in mice.

Strain-specific outcomes of repeated social defeat and chronic fluoxetine treatment in the mouse.

PubMed

Razzoli, Maria; Carboni, Lucia; Andreoli, Michela; Michielin, Francesca; Ballottari, Alice; Arban, Roberto

2011-01-01

Social stress is a risk factor for affective disorders in vulnerable individuals. Although the biological nature of stress susceptibility/resilience remains to be elucidated, genetic variation is considered amongst the principal contributors to brain disorders. Furthermore, genetic predisposition may be determinant for the therapeutic outcome, as proposed for antidepressant treatments. In the present studies we compared the inherently diverse genetic backgrounds of 2 mouse strains by assessing the efficacy of a chronic antidepressant treatment in a repeated social stress procedure. C57BL/6J and BalbC mice underwent 10-day social defeats followed by 28-day fluoxetine treatment (10 mg/kg/mL, p.o.). In C57BL/6J, most of the social defeat-induced changes were of metabolic nature including persistently altered feed efficiency and decreased abdominal fat stores that were ameliorated by fluoxetine. BalbC mouse behavior was persistently affected by social defeat both in the social avoidance and the forced swim tests, and in either procedure it was restored by chronic fluoxetine, whereas their endocrine parameters were mostly unaffected. The highlighted strain-specific responsivity to the metabolic and behavioral consequences of social defeat and to the chronic antidepressant treatment offers a promising research tool to further explore the underlying neural mechanisms and genetic basis of stress susceptibility and treatment response. Copyright © 2010 Elsevier Inc. All rights reserved.

Mice overexpressing latent matrix metalloproteinase-2 develop lung emphysema after short-term exposure to cigarette smoke extract.

PubMed

Onishi, Masahiro; Kobayashi, Tetsu; D'Alessandro-Gabazza, Corina N; Fujimoto, Hajime; Chelakkot-Govindalayathil, Ayshwarya-Lakshmi; Takahashi, Yoshinori; Yasuma, Taro; Nishihama, Kota; Toda, Masaaki; Takei, Yoshiyuki; Taguchi, Osamu; Gabazza, Esteban C

2018-02-26

Chronic obstructive pulmonary disease is the major growing cause of mortality and morbidity worldwide, and it is going to become the third most common cause of death by 2020. Chronic obstructive pulmonary disease is pathologically characterized by lung emphysema and small airway inflammation. Animal models are very important to get insights into the disease pathogenesis but current models of chronic obstructive pulmonary disease take a long time to develop. The need of a new model is compelling. In the present study we focus on the role of matrix metalloproteinases in the pathogenesis of chronic obstructive pulmonary disease and hypothesized that lung overexpression of latent matrix metalloproteinases-2 would allow the development of emphysema after short-term exposure to cigarette smoke extract inhalation. Human latent matrix metalloproteinases-2 transgenic mouse expressing high level of the protein in the lungs and wild type mouse were exposed to aerosolized cigarette smoke extract for two weeks. Transgenic mice showed significant lung emphysematous changes, increased infiltration of inflammatory cells and enhanced lung concentrations of inflammatory cytokines in the lungs compared to their wild type counterparts after inhalation of cigarette smoke extract. This novel mouse model will be a very useful tool for evaluating the mechanistic pathways and for development of novel therapies in cigarette smoke-associated lung emphysema. Copyright © 2018 Elsevier Inc. All rights reserved.

Investigating Mechanisms of Chronic Kidney Disease in Mouse Models

PubMed Central

Eddy, Allison A.; Okamura, Daryl M.; Yamaguchi, Ikuyo; López-Guisa, Jesús M.

2011-01-01

Animal models of chronic kidney disease (CKD) are important experimental tools that are used to investigate novel mechanistic pathways and to validate potential new therapeutic interventions prior to pre-clinical testing in humans. Over the past several years, mouse CKD models have been extensively used for these purposes. Despite significant limitations, the model of unilateral ureteral obstruction (UUO) has essentially become the high throughput in vivo model, as it recapitulates the fundamental pathogenetic mechanisms that typify all forms of CKD in a relatively short time span. In addition, several alternative mouse models are available that can be used to validate new mechanistic paradigms and/or novel therapies. Several models are reviewed – both genetic and experimentally induced – that provide investigators with an opportunity to include renal functional study end-points together with quantitative measures of fibrosis severity, something that is not possible with the UUO model. PMID:21695449

Stimulation of lymphangiogenesis via VEGFR-3 inhibits chronic skin inflammation.

PubMed

Huggenberger, Reto; Ullmann, Stefan; Proulx, Steven T; Pytowski, Bronislaw; Alitalo, Kari; Detmar, Michael

2010-09-27

The role of lymphangiogenesis in inflammation has remained unclear. To investigate the role of lymphatic versus blood vasculature in chronic skin inflammation, we inhibited vascular endothelial growth factor (VEGF) receptor (VEGFR) signaling by function-blocking antibodies in the established keratin 14 (K14)-VEGF-A transgenic (Tg) mouse model of chronic cutaneous inflammation. Although treatment with an anti-VEGFR-2 antibody inhibited skin inflammation, epidermal hyperplasia, inflammatory infiltration, and angiogenesis, systemic inhibition of VEGFR-3, surprisingly, increased inflammatory edema formation and inflammatory cell accumulation despite inhibition of lymphangiogenesis. Importantly, chronic Tg delivery of the lymphangiogenic factor VEGF-C to the skin of K14-VEGF-A mice completely inhibited development of chronic skin inflammation, epidermal hyperplasia and abnormal differentiation, and accumulation of CD8 T cells. Similar results were found after Tg delivery of mouse VEGF-D that only activates VEGFR-3 but not VEGFR-2. Moreover, intracutaneous injection of recombinant VEGF-C156S, which only activates VEGFR-3, significantly reduced inflammation. Although lymphatic drainage was inhibited in chronic skin inflammation, it was enhanced by Tg VEGF-C delivery. Together, these results reveal an unanticipated active role of lymphatic vessels in controlling chronic inflammation. Stimulation of functional lymphangiogenesis via VEGFR-3, in addition to antiangiogenic therapy, might therefore serve as a novel strategy to treat chronic inflammatory disorders of the skin and possibly also other organs.

Effects of Chronic Ghrelin Treatment on Hypoxia-Induced Brain Oxidative Stress and Inflammation in a Rat Normobaric Chronic Hypoxia Model.

PubMed

Omrani, Hasan; Alipour, Mohammad Reza; Farajdokht, Fereshteh; Ebrahimi, Hadi; Mesgari Abbasi, Mehran; Mohaddes, Gisou

2017-06-01

Omrani, Hasan, Mohammad Reza Alipour, Fereshteh Farajdokht, Hadi Ebrahimi, Mehran Mesgari Abbasi, and Gisou Mohaddes. Effects of chronic ghrelin treatment on hypoxia-induced brain oxidative stress and inflammation in a rat normobaric chronic hypoxia model. High Alt Med Biol. 18:145-151, 2017. This study aimed to evaluate the probable antioxidant effects of ghrelin in the brain and serum and its effect on tumor necrosis factor-alpha (TNF-α) levels in the brain in a model of chronic systemic hypoxia in rats. Systemic hypoxia was induced by a normobaric hypoxic chamber (O 2 11%) for ten days. Adult male Wistar rats were divided into control (C), chronic ghrelin (80 μg/kg/10 days) (Ghr), chronic hypoxia (CH), and CH and ghrelin (80 μg/kg/ip/10 days) (CH + Gh) groups. The activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and malondialdehyde (MDA), total antioxidant capacity, and TNF-α levels were assessed in the serum and brain tissue. Our results showed that chronic ghrelin administration attenuated the CH-increased oxidative stress by decreasing MDA levels in the serum and brain tissue. Moreover, ghrelin enhanced the antioxidant defense against hypoxia-induced oxidative stress in the serum and brain tissue. Brain TNF-α levels in CH did not change significantly; however, ghrelin significantly (p < 0.001) decreased it. These results indicated that ghrelin promoted antioxidative and anti-inflammatory defense under chronic exposure to hypoxia. Therefore, ghrelin might be used as a potential therapy in normobaric hypoxia and oxidative stress induced by CH.

Use of Humanized Mice to Study the Pathogenesis of Autoimmune and Inflammatory Diseases

PubMed Central

Koboziev, Iurii; Jones-Hall, Yava; Valentine, John F.; Webb, Cynthia Reinoso; Furr, Kathryn L.; Grisham, Matthew B.

2015-01-01

Animal models of disease have been used extensively by the research community for the past several decades to better understand the pathogenesis of different diseases as well as assess the efficacy and toxicity of different therapeutic agents. Retrospective analyses of numerous preclinical intervention studies using mouse models of acute and chronic inflammatory diseases reveal a generalized failure to translate promising interventions or therapeutics into clinically-effective treatments in patients. Although several possible reasons have been suggested to account for this generalized failure to translate therapeutic efficacy from the laboratory bench to the patient’s bedside, it is becoming increasingly apparent that the mouse immune system may not adequately recapitulate the immuno-pathological mechanisms observed in human diseases. Indeed, it is well-known that >80 major differences exist between mouse and human immunology; all of which contribute to significant differences in immune system development, activation and responses to challenges in innate and adaptive immunity. This inconvenient reality has prompted investigators to attempt to humanize the mouse immune system in order to address important, human-specific questions that are impossible to study in patients. The successful long-term engraftment of human hemato-lymphoid cells in mice would provide investigators with a relatively inexpensive, small animal model to study clinically-relevant mechanisms as well as facilitate the evaluation of human-specific therapies in vivo. The discovery that targeted mutation of the IL-2 receptor common gamma chain in lymphopenic mice allows for the long-term engraftment of functional human immune cells has advanced greatly our ability to humanize the mouse immune system. The objective of this review is to present a brief overview of the recent advances that have been made in the development and use of humanized mice with special emphasis on autoimmune and chronic inflammatory diseases. In addition, we discuss current challenges and possible solutions for utilizing these unique mouse models to define the human-specific immuno-pathological mechanisms responsible for the induction and perpetuation of chronic gut inflammation. PMID:26035036

Standardized Profiling of The Membrane-Enriched Proteome of Mouse Dorsal Root Ganglia (DRG) Provides Novel Insights Into Chronic Pain.

PubMed

Rouwette, Tom; Sondermann, Julia; Avenali, Luca; Gomez-Varela, David; Schmidt, Manuela

2016-06-01

Chronic pain is a complex disease with limited treatment options. Several profiling efforts have been employed with the aim to dissect its molecular underpinnings. However, generated results are often inconsistent and nonoverlapping, which is largely because of inherent technical constraints. Emerging data-independent acquisition (DIA)-mass spectrometry (MS) has the potential to provide unbiased, reproducible and quantitative proteome maps - a prerequisite for standardization among experiments. Here, we designed a DIA-based proteomics workflow to profile changes in the abundance of dorsal root ganglia (DRG) proteins in two mouse models of chronic pain, inflammatory and neuropathic. We generated a DRG-specific spectral library containing 3067 DRG proteins, which enables their standardized quantification by means of DIA-MS in any laboratory. Using this resource, we profiled 2526 DRG proteins in each biological replicate of both chronic pain models and respective controls with unprecedented reproducibility. We detected numerous differentially regulated proteins, the majority of which exhibited pain model-specificity. Our approach recapitulates known biology and discovers dozens of proteins that have not been characterized in the somatosensory system before. Functional validation experiments and analysis of mouse pain behaviors demonstrate that indeed meaningful protein alterations were discovered. These results illustrate how the application of DIA-MS can open new avenues to achieve the long-awaited standardization in the molecular dissection of pathologies of the somatosensory system. Therefore, our findings provide a valuable framework to qualitatively extend our understanding of chronic pain and somatosensation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Deleterious Effects of Chronic Folate Deficiency in the Ts65Dn Mouse Model of Down Syndrome

PubMed Central

Helm, Susan; Blayney, Morgan; Whited, Taylor; Noroozi, Mahjabin; Lin, Sen; Kern, Semira; Green, David; Salehi, Ahmad

2017-01-01

Folate is an important B vitamin naturally found in the human diet and plays a critical role in methylation of nucleic acids. Indeed, abnormalities in this major epigenetic mechanism play a pivotal role in the pathogenesis of cognitive deficit and intellectual disability in humans. The most common cause of cognitive dysfunction in children is Down syndrome (DS). Since folate deficiency is very common among the pediatric population, we questioned whether chronic folate deficiency (CFD) exacerbates cognitive dysfunction in a mouse model of DS. To test this, adult Ts65Dn mice and their disomic littermates were chronically fed a diet free of folic acid while preventing endogenous production of folate in the digestive tract for a period of 8 weeks. Our results show that the Ts65Dn mouse model of DS was significantly more vulnerable to CFD in terms of plasma homocysteine and N5-methyltetrahydrofolate (5-MTHF) levels. Importantly, these changes were linked to degenerative alterations in hippocampal dendritic morphology and impaired nest building behavior in Ts65Dn mice. Based on our results, a rigorous examination of folate intake and its metabolism in individuals with DS is warranted. PMID:28649192

Aging and chronic alcohol consumption are determinants of p16 gene expression, genomic DNA methylation and p16 promoter methylation in the mouse colon

USDA-ARS?s Scientific Manuscript database

Elder age and chronic alcohol consumption are important risk factors for the development of colon cancer. Each factor can alter genomic and gene-specific DNA methylation. This study examined the effects of aging and chronic alcohol consumption on genomic and p16-specific methylation, and p16 express...

Ageing, chronic alcohol consumption and folate are determinants of genomic DNA methylation, p16 promoter methylation and the expression of p16 in the mouse colon

USDA-ARS?s Scientific Manuscript database

Elder age and chronic alcohol consumption are important risk factors for the development of colon cancer. Each factor can alter genomic and gene-specific DNA methylation. This study examined the effects of aging and chronic alcohol consumption on genomic and p16-specific methylation, and p16 express...

Exercise during Short-Term and Long-Term Continuous Exposure to Hypoxia Exacerbates Sleep-Related Periodic Breathing

PubMed Central

Tellez, Helio Fernandez; Morrison, Shawnda A.; Neyt, Xavier; Mairesse, Olivier; Piacentini, Maria Francesca; Macdonald-Nethercott, Eoin; Pangerc, Andrej; Dolenc-Groselj, Leja; Eiken, Ola; Pattyn, Nathalie; Mekjavic, Igor B.; Meeusen, Romain

2016-01-01

Study Objectives: Exposure to hypoxia elevates chemosensitivity, which can lead to periodic breathing. Exercise impacts gas exchange, altering chemosensitivity; however, interactions between sleep, exercise and chronic hypoxic exposure have not been examined. This study investigated whether exercise exacerbates sleep-related periodic breathing in hypoxia. Methods: Two experimental phases. Short-Term Phase: a laboratory controlled, group-design study in which 16 active, healthy men (age: 25 ± 3 y, height: 1.79 ± 0.06 m, mass: 74 ± 8 kg) were confined to a normobaric hypoxic environment (FIO2 = 0.139 ± 0.003, 4,000 m) for 10 days, after random assignment to a sedentary (control, CON) or cycle-exercise group (EX). Long-Term Phase: conducted at the Concordia Antarctic Research Station (3,800 m equivalent at the Equator) where 14 men (age: 36 ± 9 y, height: 1.77 ± 0.09 m, mass: 75 ± 10 kg) lived for 12–14 months, continuously confined. Participants were stratified post hoc based on self-reported physical activity levels. We quantified apnea-hypopnea index (AHI) and physical activity variables. Results: Short-Term Phase: mean AHI scores were significantly elevated in the EX group compared to CON (Night1 = CON: 39 ± 51, EX: 91 ± 59; Night10 = CON: 32 ± 32, EX: 92 ± 48; P = 0.046). Long-Term Phase: AHI was correlated to mean exercise time (R2 = 0.4857; P = 0.008) and the coefficient of variation in night oxyhemoglobin saturation (SpO2; R2 = 0.3062; P = 0.049). Conclusions: Data indicate that exercise (physical activity) per se affects night SpO2 concentrations and AHI after a minimum of two bouts of moderate-intensity hypoxic exercise, while habitual physical activity in hypobaric hypoxic confinement affects breathing during sleep, up to 13+ months' duration Citation: Tellez HF, Morrison SA, Neyt X, Mairesse O, Piacentini MF, Macdonald-Nethercott E, Pangerc A, Dolenc-Groselj L, Eiken O, Pattyn N, Mekjavic IB, Meeusen R. Exercise during short-term and long-term continuous exposure to hypoxia exacerbates sleep-related periodic breathing. SLEEP 2016;39(4):773–783. PMID:26951389

A pig model of acute right ventricular afterload increase by hypoxic pulmonary vasoconstriction.

PubMed

Knai, Kathrine; Skjaervold, Nils Kristian

2017-01-03

The aim of this study was to construct a non-invasive model for acute right ventricular afterload increase by hypoxic pulmonary vasoconstriction. Intact animal models are vital to improving our understanding of the pathophysiology of acute right ventricular failure. Acute right ventricular failure is caused by increased afterload of the right ventricle by chronic or acute pulmonary hypertension combined with regionally or globally reduced right ventricular contractile capacity. Previous models are hampered by their invasiveness; this is unfortunate as the pulmonary circulation is a low-pressure system that needs to be studied in closed chest animals. Hypoxic pulmonary vasoconstriction is a mechanism that causes vasoconstriction in alveolar vessels in response to alveolar hypoxia. In this study we explored the use of hypoxic pulmonary vasoconstriction as a means to increase the pressure load on the right ventricle. Pulmonary hypertension was induced by lowering the FiO 2 to levels below the physiological range in eight anesthetized and mechanically ventilated pigs. The pigs were monitored with blood pressure measurements and blood gases. The mean pulmonary artery pressures (mPAP) of the animals increased from 18.3 (4.2) to 28.4 (4.6) mmHg and the pulmonary vascular resistance (PVR) from 254 (76) dyns/cm 5 to 504 (191) dyns/cm 5 , with a lowering of FiO 2 from 0.30 to 0.15 (0.024). The animals' individual baseline mPAPs varied substantially as did their response to hypoxia. The reduced FiO 2 level yielded an overall lowering in oxygen offer, but the global oxygen consumption was unaltered. We showed in this study that the mPAP and the PVR could be raised by approximately 100% in the study animals by lowering the FiO 2 from 0.30 to 0.15 (0.024). We therefore present a novel method for minimally invasive (closed chest) right ventricular afterload manipulations intended for future studies of acute right ventricular failure. The method should in theory be reversible, although this was not studied in this work.

Ventilation and hypoxic ventilatory responsiveness in Chinese-Tibetan residents at 3,658 m.

PubMed

Curran, L S; Zhuang, J; Sun, S F; Moore, L G

1997-12-01

When breathing ambient air at rest at 3,658 m altitude, Tibetan lifelong residents of 3,658 m ventilate as much as newcomers acclimatized to high altitude; they also ventilate more and have greater hypoxic ventilatory responses (HVRs) than do Han ("Chinese") long-term residents at 3,658 m. This suggests that Tibetan ancestry is advantageous in protecting resting ventilation levels during years of hypoxic exposure and is of interest in light of the permissive role of hypoventilation in the development of chronic mountain sickness, which is nearly absent among Tibetans. The existence of individuals with mixed Tibetan-Chinese ancestry (Han-Tibetans) residing at 3,658 m affords an opportunity to test this hypothesis. Eighteen men born in Lhasa, Tibet, China (3,658 m) to Tibetan mothers and Han fathers were compared with 27 Tibetan men and 30 Han men residing at 3,658 m who were previously studied. We used the same study procedures (minute ventilation was measured with a dry-gas flowmeter during room air breathing and hyperoxia and with a 13-liter spirometer-rebreathing system during the hypoxic and hypercapnic tests). During room air breathing at 3,658 m (inspired O2 pressure = 93 Torr), Han-Tibetans resembled Tibetans in ventilation (12.1 +/- 0.6 vs. 11.5+/- 0.5 l/min BTPS, respectively) but had HVR that were blunted (63 +/- 16 vs. 121 +/- 13, respectively, for HVR shape parameter A) and declined with increasing duration of high-altitude residence. During administered hyperoxia (inspired O2 pressure = 310 Torr) at 3,658 m, the paradoxical hyperventilation previously seen in Tibetan but not Han residents at 3,658 m (11.8 +/- 0.5 vs. 10.1 +/- 0.5 l/min BTPS) was absent in these Han-Tibetans (9.8 +/- 0.6 l/min BTPS). Thus, although longer duration of high-altitude residence appears to progressively blunt HVR among Han-Tibetans born and residing at 3, 658 m, their Tibetan ancestry appears protective in their maintenance of high resting ventilation levels despite diminished chemosensitivity.

Restorative effect of endurance exercise on behavioral deficits in the chronic mouse model of Parkinson's disease with severe neurodegeneration

PubMed Central

Pothakos, Konstantinos; Kurz, Max J; Lau, Yuen-Sum

2009-01-01

Background Animal models of Parkinson's disease have been widely used for investigating the mechanisms of neurodegenerative process and for discovering alternative strategies for treating the disease. Following 10 injections with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 25 mg/kg) and probenecid (250 mg/kg) over 5 weeks in mice, we have established and characterized a chronic mouse model of Parkinson's disease (MPD), which displays severe long-term neurological and pathological defects resembling that of the human Parkinson's disease in the advanced stage. The behavioral manifestations in this chronic mouse model of Parkinson's syndrome remain uninvestigated. The health benefit of exercise in aging and in neurodegenerative disorders including the Parkinson's disease has been implicated; however, clinical and laboratory studies in this area are limited. In this research with the chronic MPD, we first conducted a series of behavioral tests and then investigated the impact of endurance exercise on the identified Parkinsonian behavioral deficits. Results We report here that the severe chronic MPD mice showed significant deficits in their gait pattern consistency and in learning the cued version of the Morris water maze. Their performances on the challenging beam and walking grid were considerably attenuated suggesting the lack of balance and motor coordination. Furthermore, their spontaneous and amphetamine-stimulated locomotor activities in the open field were significantly suppressed. The behavioral deficits in the chronic MPD lasted for at least 8 weeks after MPTP/probenecid treatment. When the chronic MPD mice were exercise-trained on a motorized treadmill 1 week before, 5 weeks during, and 8–12 weeks after MPTP/probenecid treatment, the behavioral deficits in gait pattern, spontaneous ambulatory movement, and balance performance were reversed; whereas neuronal loss and impairment in cognitive skill, motor coordination, and amphetamine-stimulated locomotor activity were not altered when compared to the sedentary chronic MPD animals. Conclusion This study indicates that in spite of the drastic loss of dopaminergic neurons and depletion of dopamine in the severe chronic MPD, endurance exercise training effectively reverses the Parkinson's like behavioral deficits related to regular movement, balance and gait performance. PMID:19154608

Restorative effect of endurance exercise on behavioral deficits in the chronic mouse model of Parkinson's disease with severe neurodegeneration.

PubMed

Pothakos, Konstantinos; Kurz, Max J; Lau, Yuen-Sum

2009-01-20

Animal models of Parkinson's disease have been widely used for investigating the mechanisms of neurodegenerative process and for discovering alternative strategies for treating the disease. Following 10 injections with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 25 mg/kg) and probenecid (250 mg/kg) over 5 weeks in mice, we have established and characterized a chronic mouse model of Parkinson's disease (MPD), which displays severe long-term neurological and pathological defects resembling that of the human Parkinson's disease in the advanced stage. The behavioral manifestations in this chronic mouse model of Parkinson's syndrome remain uninvestigated. The health benefit of exercise in aging and in neurodegenerative disorders including the Parkinson's disease has been implicated; however, clinical and laboratory studies in this area are limited. In this research with the chronic MPD, we first conducted a series of behavioral tests and then investigated the impact of endurance exercise on the identified Parkinsonian behavioral deficits. We report here that the severe chronic MPD mice showed significant deficits in their gait pattern consistency and in learning the cued version of the Morris water maze. Their performances on the challenging beam and walking grid were considerably attenuated suggesting the lack of balance and motor coordination. Furthermore, their spontaneous and amphetamine-stimulated locomotor activities in the open field were significantly suppressed. The behavioral deficits in the chronic MPD lasted for at least 8 weeks after MPTP/probenecid treatment. When the chronic MPD mice were exercise-trained on a motorized treadmill 1 week before, 5 weeks during, and 8-12 weeks after MPTP/probenecid treatment, the behavioral deficits in gait pattern, spontaneous ambulatory movement, and balance performance were reversed; whereas neuronal loss and impairment in cognitive skill, motor coordination, and amphetamine-stimulated locomotor activity were not altered when compared to the sedentary chronic MPD animals. This study indicates that in spite of the drastic loss of dopaminergic neurons and depletion of dopamine in the severe chronic MPD, endurance exercise training effectively reverses the Parkinson's like behavioral deficits related to regular movement, balance and gait performance.

Comparative and Experimental Studies on the Genes Altered by Chronic Hypoxia in Human Brain Microendothelial Cells

PubMed Central

Mata-Greenwood, Eugenia; Goyal, Dipali; Goyal, Ravi

2017-01-01

Background : Hypoxia inducible factor 1 alpha (HIF1A) is a master regulator of acute hypoxia; however, with chronic hypoxia, HIF1A levels return to the normoxic levels. Importantly, the genes that are involved in the cell survival and viability under chronic hypoxia are not known. Therefore, we tested the hypothesis that chronic hypoxia leads to the upregulation of a core group of genes with associated changes in the promoter DNA methylation that mediates the cell survival under hypoxia. Results : We examined the effect of chronic hypoxia (3 days; 0.5% oxygen) on human brain micro endothelial cells (HBMEC) viability and apoptosis. Hypoxia caused a significant reduction in cell viability and an increase in apoptosis. Next, we examined chronic hypoxia associated changes in transcriptome and genome-wide promoter methylation. The data obtained was compared with 16 other microarray studies on chronic hypoxia. Nine genes were altered in response to chronic hypoxia in all 17 studies. Interestingly, HIF1A was not altered with chronic hypoxia in any of the studies. Furthermore, we compared our data to three other studies that identified HIF-responsive genes by various approaches. Only two genes were found to be HIF dependent. We silenced each of these 9 genes using CRISPR/Cas9 system. Downregulation of EGLN3 significantly increased the cell death under chronic hypoxia, whereas downregulation of ERO1L, ENO2, adrenomedullin, and spag4 reduced the cell death under hypoxia. Conclusions : We provide a core group of genes that regulates cellular acclimatization under chronic hypoxic stress, and most of them are HIF independent. PMID:28620317

Sulphonylurea drugs reduce hypoxic damage in the isolated perfused rat kidney.

PubMed

Engbersen, R; Moons, M M; Wouterse, A C; Dijkman, H B; Kramers, C; Smits, P; Russel, F G

2000-08-01

Sulphonylurea drugs have been shown to protect against hypoxic damage in isolated proximal tubules of the kidney. In the present study we investigated whether these drugs can protect against hypoxic damage in a whole kidney preparation. Tolbutamide (200 microM) and glibenclamide (10 microM) were applied to the isolated perfused rat kidney prior to changing the gassing from oxygen to nitrogen for 30 min. Hypoxic perfusions resulted in an increased fractional excretion of glucose (FE % glucose 14.3+/-1.5 for hypoxic perfusions vs 4.9+/-1.6 for normoxic perfusions, mean +/- s.e. mean, P<0.05), which could be completely restored by 200 microM tolbutamide (5.7+/-0.4 for tolbutamide vs 14.3+/-1.5 for untreated hypoxic kidneys, P<0.01). Furthermore, tolbutamide reduced the total amount of LDH excreted in the urine (220+/-100 mU for tolbutamide vs. 1220+/-160 mU for untreated hypoxic kidneys, P<0.01). Comparable results were obtained with glibenclamide (10 microM). In agreement with the effect on functional parameters, ultrastructural analysis of proximal tubules showed increased brush border preservation in tolbutamide treated kidneys compared to untreated hypoxic kidneys. We conclude that glibenclamide and tolbutamide are both able to reduce hypoxic damage to proximal tubules in the isolated perfused rat kidney when applied in the appropriate concentrations.

The effects of hypoxic bradycardia and extracellular HCO3(-)/CO2 on hypoxic performance in the eel heart.

PubMed

Joyce, William; Simonsen, Maj; Gesser, Hans; Wang, Tobias

2016-02-01

During hypoxia, fishes exhibit a characteristic hypoxic bradycardia, the functional significance of which remains debated. Here, we investigated the hypothesis that hypoxic bradycardia primarily safeguards cardiac performance. In preparations from the European eel (Anguilla anguilla), a decrease in stimulation frequency from 40 to 15 beats min(-1), which replicates hypoxic bradycardia in vivo, vastly improved cardiac performance during hypoxia in vitro. As eels display dramatic shifts in extracellular HCO3(-)/CO2, we further investigated the effect this has upon hypoxic cardiac performance. Elevations from 10 mmol l(-1) HCO3(-)/1% CO2 to 40 mmol l(-1) HCO3(-)/4% CO2 had few effects on performance; however, further, but still physiologically relevant, increases to 70 mmol l(-1) HCO3(-)/7% CO2 compromised hypoxia tolerance. We revealed a four-way interaction between HCO3(-)/CO2, contraction frequency, hypoxia and performance over time, whereby the benefit of hypoxic bradycardia was most prolonged at 10 mmol l(-1) HCO3(-)/1% CO2. Together, our data suggest that hypoxic bradycardia greatly benefits cardiac performance, but its significance may be context specific. © 2016. Published by The Company of Biologists Ltd.

A scenario and forecast model for Gulf of Mexico hypoxic area and volume

USGS Publications Warehouse

Scavia, Donald; Evans, Mary Anne; Obenour, Daniel R.

2013-01-01

For almost three decades, the relative size of the hypoxic region on the Louisiana-Texas continental shelf has drawn scientific and policy attention. During that time, both simple and complex models have been used to explore hypoxia dynamics and to provide management guidance relating the size of the hypoxic zone to key drivers. Throughout much of that development, analyses had to accommodate an apparent change in hypoxic sensitivity to loads and often cull observations due to anomalous meteorological conditions. Here, we describe an adaptation of our earlier, simple biophysical model, calibrated to revised hypoxic area estimates and new hypoxic volume estimates through Bayesian estimation. This application eliminates the need to cull observations and provides revised hypoxic extent estimates with uncertainties, corresponding to different nutrient loading reduction scenarios. We compare guidance from this model application, suggesting an approximately 62% nutrient loading reduction is required to reduce Gulf hypoxia to the Action Plan goal of 5,000 km2, to that of previous applications. In addition, we describe for the first time, the corresponding response of hypoxic volume. We also analyze model results to test for increasing system sensitivity to hypoxia formation, but find no strong evidence of such change.

Comparative sequence analysis of a region on human chromosome 13q14, frequently deleted in B-cell chronic lymphocytic leukemia, and its homologous region on mouse chromosome 14.

PubMed

Kapanadze, B; Makeeva, N; Corcoran, M; Jareborg, N; Hammarsund, M; Baranova, A; Zabarovsky, E; Vorontsova, O; Merup, M; Gahrton, G; Jansson, M; Yankovsky, N; Einhorn, S; Oscier, D; Grandér, D; Sangfelt, O

2000-12-15

Previous studies have indicated the presence of a putative tumor suppressor gene on human chromosome 13q14, commonly deleted in patients with B-cell chronic lymphocytic leukemia (B-CLL). We have recently identified a minimally deleted region encompassing parts of two adjacent genes, termed LEU1 and LEU2 (leukemia-associated genes 1 and 2), and several additional transcripts. In addition, 50 kb centromeric to this region we have identified another gene, LEU5/RFP2. To elucidate further the complex genomic organization of this region, we have identified, mapped, and sequenced the homologous region in the mouse. Fluorescence in situ hybridization analysis demonstrated that the region maps to mouse chromosome 14. The overall organization and gene order in this region were found to be highly conserved in the mouse. Sequence comparison between the human deletion hotspot region and its homologous mouse region revealed a high degree of sequence conservation with an overall score of 74%. However, our data also show that in terms of transcribed sequences, only two of those, human LEU2 and LEU5/RFP2, are clearly conserved, strengthening the case for these genes as putative candidate B-CLL tumor suppressor genes.

Lead intoxication under environmental hypoxia impairs oral health.

PubMed

Terrizzi, Antonela R; Fernandez-Solari, Javier; Lee, Ching M; Martínez, María Pilar; Conti, María Ines

2014-01-01

We have reported that chronic lead intoxication under hypoxic environment induces alveolar bone loss that can lead to periodontal damage with the subsequent loss of teeth. The aim of the present study was to assess the modification of oral inflammatory parameters involved in the pathogenesis of periodontitis in the same experimental model. In gingival tissue, hypoxia increased inducible nitric oxid synthase (iNOS) activity (p < .01) and meanwhile lead decreased prostaglandin E2 (PGE2) content (p < .05). In submandibular gland (SMG), iNOS activity was enhanced by lead and PGE2 content was increased by both lead and hypoxia (p < .01) and even more by combined treatments (p < .001). In the SMG, hypoxia stimulated angiogenesis (p < .01) with blood extravasation. Adrenal glands were 22% bigger in those animals exposed to lead under hypoxic conditions. Results suggest a wide participation of inflammatory markers that mediate alveolar bone loss induced by these environmental conditions. The lack of information regarding oral health in lead-contaminated populations that coexist with hypoxia induced us to evaluate the alteration of inflammatory parameters in rat oral tissues to elucidate the link between periodontal damage and these environmental conditions.

CRISPR-Mediated Knockout of Cybb in NSG Mice Establishes a Model of Chronic Granulomatous Disease for Human Stem-Cell Gene Therapy Transplants.

PubMed

Sweeney, Colin L; Choi, Uimook; Liu, Chengyu; Koontz, Sherry; Ha, Seung-Kwon; Malech, Harry L

2017-07-01

Chronic granulomatous disease (CGD) is characterized by defects in the production of microbicidal reactive oxygen species (ROS) by phagocytes. Testing of gene and cell therapies for the treatment of CGD in human hematopoietic cells requires preclinical transplant models. The use of the lymphocyte-deficient NOD.Cg-Prkdc scid Il2rg tm1Wjl/ SzJ (NSG) mouse strain for human hematopoietic cell xenografts to test CGD therapies is complicated by the presence of functional mouse granulocytes capable of producing ROS for subsequent bacterial and fungal killing. To establish a phagocyte-defective mouse model of X-linked CGD (X-CGD) in NSG mice, clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 was utilized for targeted knockout of mouse Cybb on the X-chromosome by microinjection of NSG mouse zygotes with Cas9 mRNA and CRISPR single-guide RNA targeting Cybb exon 1 or exon 3. This resulted in a high incidence of indel formation at the CRISPR target site, with all mice exhibiting deletions in at least one Cybb allele based on sequence analysis of tail snip DNA. A female mouse heterozygous for a 235-bp deletion in Cybb exon 1 was bred to an NSG male to establish the X-CGD NSG mouse strain, NSG.Cybb[KO]. Resulting male offspring with the 235 bp deletion were found to be defective for production of ROS by neutrophils and other phagocytes, and demonstrated increased susceptibility to spontaneous bacterial and fungal infections with granulomatous inflammation. The establishment of the phagocyte-defective NSG.Cybb[KO] mouse model enables the in vivo assessment of gene and cell therapy strategies for treating CGD in human hematopoietic cell transplants without obfuscation by functional mouse phagocytes, and may also be useful for modeling other phagocyte disorders in humanized NSG mouse xenografts.

The effects of levosimendan and glibenclamide on circulatory and metabolic variables in a canine model of acute hypoxia.

PubMed

Schwarte, Lothar A; Schwartges, Ingo; Thomas, Kai; Schober, Patrick; Picker, Olaf

2011-04-01

To study the effects of pretreatment with levosimendan (LEVO, a Ca²(+)-sensitizer and K (ATP) (+) channel opener) and/or the K (ATP) (+) channel antagonist glibenclamide (GLIB) on systemic hemodynamics, metabolism, and regional gastromucosal oxygenation during hypoxic hypoxemia. Chronically instrumented, healthy dogs (24-32 kg, n = 6 per group, randomized cross-over design) were repeatedly sedated, mechanically ventilated (FiO₂ ~0.3) and subjected to the following interventions: no pretreatment, LEVO pretreatment, GLIB pretreatment, or combined LEVO + GLIB pretreatment, each followed by hypoxic hypoxemia (FiO₂ ~0.1). We measured cardiac output (CO, ultrasonic flow probes), oxygen consumption (VO₂, indirect calorimetry), and gastromucosal microvascular hemoglobin oxygenation (μHbO₂, spectrophotometry). data are presented as mean ± SEM and compared by one-way ANOVA (direct drug effects within group) and two-way ANOVA (between all hypoxic conditions) both with Bonferroni corrections; p < 0.05. In LEVO-pretreated hypoxemia, CO was significantly higher compared to unpretreated hypoxemia. The increased CO was neither associated with an increased VO₂ nor with markers of aggravated anaerobiosis (pH, BE, lactate). In addition, LEVO pretreatment did not further compromise gastromucosal μHbO₂ in hypoxemia. After combined LEVO + GLIB pretreatment, systemic effects of GLIB were apparent, however, CO was significantly higher than during unpretreated and GLIB-pretreated hypoxemia, but equal to LEVO-pretreated hypoxemia, indicating that GLIB did not prevent the increased CO in LEVO-pretreated hypoxia. LEVO pretreatment resulted in improved systemic circulation (CO) during hypoxemia without fueling systemic VO₂, without aggravating systemic anaerobiosis markers, and without further compromising microvascular gastromucosal oxygenation. Thus, LEVO pretreatment may be an option to support the systemic circulation during hypoxia.

Hypoxic pulmonary vasodilation: a paradigm shift with a hydrogen sulfide mechanism

PubMed Central

Whitfield, Nathan L.; Bearden, Shawn E.; St. Leger, Judy; Nilson, Erika; Gao, Yan; Madden, Jane A.

2010-01-01

Hypoxic pulmonary vasoconstriction (HVC), an intrinsic and assumed ubiquitous response of mammalian pulmonary blood vessels, matches regional ventilation to perfusion via an unknown O2-sensing mechanism. Global pulmonary hypoxia experienced by individuals suffering from chronic obstructive pulmonary disease or numerous hypoventilation syndromes, including sleep apnea, often produces maladaptive pulmonary hypertension, but pulmonary hypertension is not observed in diving mammals, where profound hypoxia is routine. Here we examined the response of cow and sea lion pulmonary arteries (PA) to hypoxia and observed the expected HVC in the former and a unique hypoxic vasodilation in resistance vessels in the latter. We then used this disparate response to examine the O2-sensing mechanism. In both animals, exogenous H2S mimicked the vasoactive effects of hypoxia in isolated PA. H2S-synthesizing enzymes, cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfur transferase, were identified in lung tissue from both animals by one-dimensional Western blot analysis and immunohistochemistry. The relationship between H2S production/consumption and O2 was examined in real time by use of amperometric H2S and O2 sensors. H2S was produced by sea lion and cow lung homogenate in the absence of O2, but it was rapidly consumed when O2 was present. Furthermore, consumption of exogenous H2S by cow lung homogenate, PA smooth muscle cells, and heart mitochondria was O2 dependent and exhibited maximal sensitivity at physiologically relevant Po2 levels. These studies show that HVC is not an intrinsic property of PA and provide further evidence for O2-dependent H2S metabolism in O2 sensing. PMID:19889863

Activity of the hypoxia-activated prodrug, TH-302, in preclinical human acute myeloid leukemia models.

PubMed

Portwood, Scott; Lal, Deepika; Hsu, Yung-Chun; Vargas, Rodrigo; Johnson, Megan K; Wetzler, Meir; Hart, Charles P; Wang, Eunice S

2013-12-01

Acute myeloid leukemia (AML) is an aggressive hematologic neoplasm. Recent evidence has shown the bone marrow microenvironment in patients with AML to be intrinsically hypoxic. Adaptive cellular responses by leukemia cells to survive under low oxygenation also confer chemoresistance. We therefore asked whether therapeutic exploitation of marrow hypoxia via the hypoxia-activated nitrogen mustard prodrug, TH-302, could effectively inhibit AML growth. We assessed the effects of hypoxia and TH-302 on human AML cells, primary samples, and systemic xenograft models. We observed that human AML cells and primary AML colonies cultured under chronic hypoxia (1% O2, 72 hours) exhibited reduced sensitivity to cytarabine-induced apoptosis as compared with normoxic controls. TH-302 treatment resulted in dose- and hypoxia-dependent apoptosis and cell death in diverse AML cells. TH-302 preferentially decreased proliferation, reduced HIF-1α expression, induced cell-cycle arrest, and enhanced double-stranded DNA breaks in hypoxic AML cells. Hypoxia-induced reactive oxygen species by AML cells were also diminished. In systemic human AML xenografts (HEL, HL60), TH-302 [50 mg/kg intraperitoneally (i.p.) 5 times per week] inhibited disease progression and prolonged overall survival. TH-302 treatment reduced the number of hypoxic cells within leukemic bone marrows and was not associated with hematologic toxicities in nonleukemic or leukemic mice. Later initiation of TH-302 treatment in advanced AML disease was as effective as earlier TH-302 treatment in xenograft models. Our results establish the preclinical activity of TH-302 in AML and provide the rationale for further clinical studies of this and other hypoxia-activated agents for leukemia therapy. ©2013 AACR.

40 CFR 161.340 - Toxicology data requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... TGAI TGAI 83-1 Oncogenicity study—2 Spp. rat and mouse preferred (9), (21) R CR R CR R CR CR CR CR TGAI.... (C) Chronic nonrodent (i.e., dog) feeding study—12 months. (D) Mouse oncogenicity study—18 months. (E..., metaplasia) in any organ that may lead to neoplastic change. (ii) The use requires a tolerance for the...

Hypoxia enhances the protective effects of placenta-derived mesenchymal stem cells against scar formation through hypoxia-inducible factor-1α.

PubMed

Du, Lili; Lv, Runxiao; Yang, Xiaoyi; Cheng, Shaohang; Xu, Jing; Ma, Tingxian

2016-06-01

To explore the effect of placenta-derived mesenchymal stem cells on scar formation as well as the underlying mechanism. The isolated placenta-derived mesenchymal stem cells from mice were distributed in the wounded areas of scalded mouse models, attenuated inflammatory responses and decreased the deposition of collagens, thus performing a beneficial effect against scar formation. Hypoxia enhanced the protective effect of placenta-derived mesenchymal stem cells and hypoxia-inducible factor-1α was involved in the protective effect of placenta-derived mesenchymal stem cells in hypoxic condition. Hypoxia enhanced the protective effect of placenta-derived mesenchymal stem cells through hypoxia-inducible factor-1α and PMSCs may have a potential application in the treatment of wound.

Toward hypoxia-selective rhenium and technetium tricarbonyl complexes.

PubMed

North, Andrea J; Hayne, David J; Schieber, Christine; Price, Katherine; White, Anthony R; Crouch, Peter J; Rigopoulos, Angela; O'Keefe, Graeme J; Tochon-Danguy, Henri; Scott, Andrew M; White, Jonathan M; Ackermann, Uwe; Donnelly, Paul S

2015-10-05

With the aim of preparing hypoxia-selective imaging and therapeutic agents, technetium(I) and rhenium(I) tricarbonyl complexes with pyridylhydrazone, dipyridylamine, and pyridylaminocarboxylate ligands containing nitrobenzyl or nitroimidazole functional groups have been prepared. The rhenium tricarbonyl complexes were synthesized with short reaction times using microwave irradiation. Rhenium tricarbonyl complexes with deprotonated p-nitrophenyl pyridylhydrazone ligands are luminescent, and this has been used to track their uptake in HeLa cells using confocal fluorescent microscopy. Selected rhenium tricarbonyl complexes displayed higher uptake in hypoxic cells when compared to normoxic cells. A (99m)Tc tricarbonyl complex with a dipyridylamine ligand bearing a nitroimidazole functional group is stable in human serum and was shown to localize in a human renal cell carcinoma (RCC; SK-RC-52) tumor in a mouse.

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells.

PubMed

Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

2016-08-05

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4-5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba(2+)-sensitive inward rectifier K(+) current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level but not at mRNA level after the hypoxic culture. Ca(2+) imaging study revealed that the hypoxic stress enhanced store-operated Ca(2+) (SOC) entry, which was significantly reduced in the presence of 100 μM Ba(2+). On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba(2+). We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca(2+) entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of microcirculation dynamics during cutaneous wound healing phases in vivo using optical microangiography

PubMed Central

Yousefi, Siavash; Qin, Jia; Dziennis, Suzan; Wang, Ruikang K.

2014-01-01

Abstract. Cutaneous wound healing consists of multiple overlapping phases starting with blood coagulation following incision of blood vessels. We utilized label-free optical coherence tomography and optical microangiography (OMAG) to noninvasively monitor healing process and dynamics of microcirculation system in a mouse ear pinna wound model. Mouse ear pinna is composed of two layers of skin separated by a layer of cartilage and because its total thickness is around 500 μm, it can be utilized as an ideal model for optical imaging techniques. These skin layers are identical to human skin structure except for sweat ducts and glands. Microcirculatory system responds to the wound injury by recruiting collateral vessels to supply blood flow to hypoxic region. During the inflammatory phase, lymphatic vessels play an important role in the immune response of the tissue and clearing waste from interstitial fluid. In the final phase of wound healing, tissue maturation, and remodeling, the wound area is fully closed while blood vessels mature to support the tissue cells. We show that using OMAG technology allows noninvasive and label-free monitoring and imaging each phase of wound healing that can be used to replace invasive tissue sample histology and immunochemistry technologies. PMID:25036212

Extracerebral Tissue Damage in the Intraluminal Filament Mouse Model of Middle Cerebral Artery Occlusion

PubMed Central

Vaas, Markus; Ni, Ruiqing; Rudin, Markus; Kipar, Anja; Klohs, Jan

2017-01-01

Middle cerebral artery occlusion is the most common model of focal cerebral ischemia in the mouse. In the surgical procedure, the external carotid artery (ECA) is ligated; however, its effect on the tissue supplied by the vessel has not been described so far. C57BL/6 mice underwent 1 h of transient MCAO (tMCAO) or sham surgery. Multi-spectral optoacoustic tomography was employed at 30 min after surgery to assess oxygenation in the temporal muscles. Microstructural changes were assessed with magnetic resonance imaging and histological examination at 24 h and 48 h after surgery. Ligation of the ECA resulted in decreased oxygenation of the left temporal muscle in most sham-operated and tMCAO animals. Susceptible mice of both groups exhibited increased T2 relaxation times in the affected muscle with histological evidence of myofibre degeneration, interstitial edema, and neutrophil influx. Ligatures had induced an extensive neutrophil-dominated inflammatory response. ECA ligation leads to distinct hypoxic degenerative changes in the tissue of the ECA territory and to ligature-induced inflammatory processes. An impact on outcome needs to be considered in this stroke model. PMID:28348545

Colforsin-induced vasodilation in chronic hypoxic pulmonary hypertension in rats.

PubMed

Yokochi, Ayumu; Itoh, Hiroo; Maruyama, Junko; Zhang, Erquan; Jiang, Baohua; Mitani, Yoshihide; Hamada, Chikuma; Maruyama, Kazuo

2010-06-01

Colforsin, a water-soluble forskolin derivative, directly activates adenylate cyclase and thereby increases the 3',5'-cyclic adenosine monophosphate (cAMP) level in vascular smooth muscle cells. In this study, we investigated the vasodilatory action of colforsin on structurally remodeled pulmonary arteries from rats with pulmonary hypertension (PH). A total of 32 rats were subjected to hypobaric hypoxia (380 mmHg, 10% oxygen) for 10 days to induce chronic hypoxic PH, while 39 rats were kept in room air. Changes in isometric force were recorded in endothelium-intact (+E) and -denuded (-E) pulmonary arteries from the PH and control (non-PH) rats. Colforsin-induced vasodilation was impaired in both +E and -E arteries from PH rats compared with their respective controls. Endothelial removal did not influence colforsin-induced vasodilation in the arteries from control rats, but attenuated it in arteries from PH rats. The inhibition of nitric oxide (NO) synthase did not influence colforsin-induced vasodilation in +E arteries from controls, but attenuated it in +E arteries from PH rats, shifting its concentration-response curve closer to that of -E arteries from PH rats. Vasodilation induced by 8-bromo-cAMP (a cell-permeable cAMP analog) was also impaired in -E arteries from PH rats, but not in +E arteries from PH rats, compared with their respective controls. cAMP-mediated vasodilatory responses without beta-adrenergic receptor activation are impaired in structurally remodeled pulmonary arteries from PH rats. In these arteries, endothelial cells presumably play a compensatory role against the impaired cAMP-mediated vasodilatory response by releasing NO (and thereby attenuating the impairment). The results suggest that colforsin could be effective in the treatment of PH.

Environmental enrichment synergistically improves functional recovery by transplanted adipose stem cells in chronic hypoxic-ischemic brain injury.

PubMed

Seo, Jung Hwa; Kim, Hyongbum; Park, Eun Sook; Lee, Jong Eun; Kim, Dong Wook; Kim, Hyun Ok; Im, Sang Hee; Yu, Ji Hea; Kim, Ji Yeon; Lee, Min-Young; Kim, Chul Hoon; Cho, Sung-Rae

2013-01-01

We investigated the effects of environmental enrichment (EE) on the function of transplanted adipose stem cells (ASCs) and the combined effect of EE and ASC transplantation on neurobehavioral function in an animal model of chronic hypoxic-ischemic (HI) brain injury. HI brain damage was induced in 7-day-old mice by unilateral carotid artery ligation and exposure to hypoxia (8% O2 for 90 min). At 6 weeks of age, the mice were randomly injected with either ASCs or PBS into the striatum and were randomly assigned to either EE or standard cages (SC), comprising ASC-EE (n=18), ASC-SC (n=19), PBS-EE (n=12), PBS-SC (n=17), and untreated controls (n=23). Rotarod, forelimb-use asymmetry, and grip strength tests were performed to evaluate neurobehavioral function. The fate of transplanted cells and the levels of endogenous neurogenesis, astrocyte activation, and paracrine factors were also measured. As a result, EE and ASC transplantation synergistically improved rotarod latency, forelimb-use asymmetry, and grip strength compared to those of the other groups. The number of engrafted ASCs and βIII-tubulin(+) neurons derived from the transplanted ASCs was significantly higher in mice in EE than those in SC. EE and ASC transplantation also synergistically increased BrdU(+)βIII-tubulin(+) neurons, GFAP(+) astrocytic density, and fibroblast growth factor 2 (FGF2) level but not the level of CS-56(+) glial scarring in the striatum. In conclusion, EE and ASC transplantation synergistically improved neurobehavioral functions. The underlying mechanisms of this synergism included enhanced repair processes such as higher engraftment of the transplanted ASCs, increased endogenous neurogenesis and astrocytic activation coupled with upregulation of FGF2.

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

Khadjavi, Amina; Magnetto, Chiara; Panariti, Alice

Background: : In chronic wounds, efficient epithelial tissue repair is hampered by hypoxia, and balances between the molecules involved in matrix turn-over such as matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are seriously impaired. Intriguingly, new oxygenating nanocarriers such as 2H,3H-decafluoropentane-based oxygen-loaded nanodroplets (OLNs) might effectively target chronic wounds. Objective: : To investigate hypoxia and chitosan-shelled OLN effects on MMP/TIMP production by human keratinocytes. Methods: : HaCaT cells were treated for 24 h with 10% v/v OLNs both in normoxia or hypoxia. Cytotoxicity and cell viability were measured through biochemical assays; cellular uptake by confocal microscopy; and MMPmore » and TIMP production by enzyme-linked immunosorbent assay or gelatin zymography. Results: : Normoxic HaCaT cells constitutively released MMP-2, MMP-9, TIMP-1 and TIMP-2. Hypoxia strongly impaired MMP/TIMP balances by reducing MMP-2, MMP-9, and TIMP-2, without affecting TIMP-1 release. After cellular uptake by keratinocytes, nontoxic OLNs abrogated all hypoxia effects on MMP/TIMP secretion, restoring physiological balances. OLN abilities were specifically dependent on time-sustained oxygen diffusion from OLN core. Conclusion: : Chitosan-shelled OLNs effectively counteract hypoxia-dependent dysregulation of MMP/TIMP balances in human keratinocytes. Therefore, topical administration of exogenous oxygen, properly encapsulated in nanodroplet formulations, might be a promising adjuvant approach to promote healing processes in hypoxic wounds. - Highlights: • Hypoxia impairs MMP9/TIMP1 and MMP2/TIMP2 balances in HaCaT human keratinocytes. • Chitosan-shelled oxygen-loaded nanodroplets (OLNs) are internalised by HaCaT cells. • OLNs are not toxic to HaCaT cells. • OLNs effectively counteract hypoxia effects on MMP/TIMP balances in HaCaT cells. • OLNs appear as promising and cost-effective therapeutic tools for hypoxic wounds.« less

Hypoxic pretreatment protects against neuronal damage of the rat hippocampus induced by severe hypoxia.

PubMed

Gorgias, N; Maidatsi, P; Tsolaki, M; Alvanou, A; Kiriazis, G; Kaidoglou, K; Giala, M

1996-04-01

The present study investigates whether under conditions of successive hypoxic exposures pretreatment with mild (15% O(2)) or moderate (10% O(2)) hypoxia, protects hippocampal neurones against damage induced by severe (3% O(2)) hypoxia. The ultrastructural findings were also correlated with regional superoxide dismutase (SOD) activity changes. In unpretreated rats severe hypoxia induced ultrastructural changes consistent with the aspects of delayed neuronal death (DND). However, in preexposed animals hippocampal damage was attenuated in an inversely proportional way with the severity of the hypoxic pretreatment. The ultrastructural hypoxic tolerance findings were also closely related to increased regional SOD activity levels. Thus the activation of the endogenous antioxidant defense by hypoxic preconditioning, protects against hippocampal damage induced by severe hypoxia. The eventual contribution of increased endogenous adenosine and/or reduced excitotoxicity to induce hypoxic tolerance is discussed.

Sulphonylurea drugs reduce hypoxic damage in the isolated perfused rat kidney

PubMed Central

Engbersen, Richard; Moons, Miek M; Wouterse, Alfons C; Dijkman, Henry B; Kramers, Cees; Smits, Paul; Russel, Frans G M

2000-01-01

Sulphonylurea drugs have been shown to protect against hypoxic damage in isolated proximal tubules of the kidney. In the present study we investigated whether these drugs can protect against hypoxic damage in a whole kidney preparation. Tolbutamide (200 μM) and glibenclamide (10 μM) were applied to the isolated perfused rat kidney prior to changing the gassing from oxygen to nitrogen for 30 min. Hypoxic perfusions resulted in an increased fractional excretion of glucose (FE % glucose 14.3±1.5 for hypoxic perfusions vs 4.9±1.6 for normoxic perfusions, mean±s.e.mean, P<0.05), which could be completely restored by 200 μM tolbutamide (5.7±0.4 for tolbutamide vs 14.3±1.5 for untreated hypoxic kidneys, P<0.01). Furthermore, tolbutamide reduced the total amount of LDH excreted in the urine (220±100 mU for tolbutamide vs 1220±160 mU for untreated hypoxic kidneys, P<0.01). Comparable results were obtained with glibenclamide (10 μM). In agreement with the effect on functional parameters, ultrastructural analysis of proximal tubules showed increased brush border preservation in tolbutamide treated kidneys compared to untreated hypoxic kidneys. We conclude that glibenclamide and tolbutamide are both able to reduce hypoxic damage to proximal tubules in the isolated perfused rat kidney when applied in the appropriate concentrations. PMID:10928974

Hypoxic-Preconditioned Bone Marrow Stem Cell Medium Significantly Improves Outcome After Retinal Ischemia in Rats

PubMed Central

Roth, Steven; Dreixler, John C.; Mathew, Biji; Balyasnikova, Irina; Mann, Jacob R.; Boddapati, Venkat; Xue, Lai; Lesniak, Maciej S.

2016-01-01

Purpose We have previously demonstrated the protective effect of bone marrow stem cell (BMSC)-conditioned medium in retinal ischemic injury. We hypothesized here that hypoxic preconditioning of stem cells significantly enhances the neuroprotective effect of the conditioned medium and thereby augments the protective effect in ischemic retina. Methods Rats were subjected to retinal ischemia by increasing intraocular pressure to 130 to 135 mm Hg for 55 minutes. Hypoxic-preconditioned, hypoxic unconditioned, or normoxic medium was injected into the vitreous 24 hours after ischemia ended. Recovery was assessed 7 days after injections by comparing electroretinography measurements, histologic examination, and apoptosis (TUNEL, terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling assay). To compare proteins secreted into the medium in the groups and the effect of hypoxic exposure, we used rat cytokine arrays. Results Eyes injected with hypoxic BMSC–conditioned medium 24 hours after ischemia demonstrated significantly enhanced return of retinal function, decreased retinal ganglion cell layer loss, and attenuated apoptosis compared to those administered normoxic or hypoxic unconditioned medium. Hypoxic-preconditioned medium had 21 significantly increased protein levels compared to normoxic medium. Conclusions The medium from hypoxic-preconditioned BMSCs robustly restored retinal function and prevented cell loss after ischemia when injected 24 hours after ischemia. The protective effect was even more pronounced than in our previous studies of normoxic conditioned medium. Prosurvival signals triggered by the secretome may play a role in this neuroprotective effect. PMID:27367588

A model study of the response of hypoxia to upwelling-favorable wind on the northern Gulf of Mexico shelf

NASA Astrophysics Data System (ADS)

Feng, Yang; Fennel, Katja; Jackson, George A.; DiMarco, Steven F.; Hetland, Robert D.

2014-03-01

The hypoxic region in the northern Gulf of Mexico, one of the largest man-made hypoxic zones in the world, has received extensive scientific study and management interest. A previous statistical study has concluded that in addition to anthropogenic nitrogen loading, the observed hypoxic extent is correlated to the duration of upwelling favorable (westerly) wind without elucidating the underlying mechanism. In this study, we use a three-dimensional, coupled hydrological-biogeochemical model to mechanistically examine how variations of the hypoxic area are related to the duration of upwelling-favorable wind. We performed scenario experiments with different durations of upwelling-favorable wind using realistic winds from summer 2002 (when upwelling-favorable winds were present only for about 1 month) and summer 2009 (when upwelling-favorable conditions started early and persisted for about 2 months). While the maximum simulated hypoxic area is approximately 15,000 km2 in both cases, the evolutions of the hypoxic area and the dates when its maximum extent are reached are different. With an early start of persistently upwelling-favorable wind in 2009, the hypoxic area reached its maximum in early summer and decreased afterwards. By contrast, the hypoxic area was small in early summer of 2002 and peaked during the short period of upwelling-favorable wind in late summer. The model revealed that the wind influences the evolution of the hypoxic area by changing the vertical and horizontal distributions of the low salinity, high chlorophyll water on the shelf.

Neuroglobin overexpression inhibits oxygen-glucose deprivation-induced mitochondrial permeability transition pore opening in primary cultured mouse cortical neurons.

PubMed

Yu, Zhanyang; Liu, Ning; Li, Yadan; Xu, Jianfeng; Wang, Xiaoying

2013-08-01

Neuroglobin (Ngb) is an endogenous neuroprotective molecule against hypoxic/ischemic brain injury, but the underlying mechanisms remain largely undefined. Our recent study revealed that Ngb can bind to voltage-dependent anion channel (VDAC), a regulator of mitochondria permeability transition (MPT). In this study we examined the role of Ngb in MPT pore (mPTP) opening following oxygen-glucose deprivation (OGD) in primary cultured mouse cortical neurons. Co-immunoprecipitation (Co-IP) and immunocytochemistry showed that the binding between Ngb and VDAC was increased after OGD compared to normoxia, indicating the OGD-enhanced Ngb-VDAC interaction. Ngb overexpression protected primary mouse cortical neurons from OGD-induced neuronal death, to an extent comparable to mPTP opening inhibitor, cyclosporine A (CsA) pretreatment. We further measured the role of Ngb in OGD-induced mPTP opening using Ngb overexpression and knockdown approaches in primary cultured neurons, and recombinant Ngb exposure to isolated mitochondria. Same as CsA pretreatment, Ngb overexpression significantly reduced OGD-induced mPTP opening markers including mitochondria swelling, mitochondrial NAD(+) release, and cytochrome c (Cyt c) release in primary cultured neurons. Recombinant Ngb incubation significantly reduced OGD-induced NAD(+) release and Cyt c release from isolated mitochondria. In contrast, Ngb knockdown significantly increased OGD-induced neuron death, and increased OGD-induced mitochondrial NAD(+) release and Cyt c release as well, and these outcomes could be rescued by CsA pretreatment. In summary, our results demonstrated that Ngb overexpression can inhibit OGD-induced mPTP opening in primary cultured mouse cortical neurons, which may be one of the molecular mechanisms of Ngb's neuroprotection. Copyright © 2013 Elsevier Inc. All rights reserved.

Microvasculature remodeling in the mouse lower gut during inflammaging

PubMed Central

Jeong, Jae-Ho; Kim, KwangSoo; Lim, Daejin; Kim, Kun-Hee; Kim, Hyung-Seok; Lee, Sungsu; Song, Joo-Hye; Moon, Byoung-Gon; Choy, Hyon E.; Park, Sang Chul

2017-01-01

Inflammaging is defined as low-grade, chronic, systemic inflammation in aging, in the absence of overt infection. Age-associated deterioration of gastrointestinal function could be ascribed to the inflammaging, although evidence is yet to emerge. Here we show that microvessels in aging mouse intestine were progressively deprived of supportive structures, microvessel-associated pericytes and adherens junction protein vascular endothelial (VE)-cadherin, and became leaky. This alteration was ascribed to up-regulation of angiopoetin-2 in microvascular endothelial cells. Up-regulation of the angiopoietin-2 was by TNF-α, originated from M2-like residential CD206+ macrophages, proportion of which increases as animal ages. It was concluded that antigenic burdens encountered in intestine throughout life create the condition of chronic stage of inflammation, which accumulates M2-like macrophages expressing TNF-α. The TNF-α induces vascular leakage to facilitate recruitment of immune cells into intestine under the chronic inflammatory setting. PMID:28045067

Changes in gene expression in chronic allergy mouse model exposed to natural environmental PM2.5-rich ambient air pollution.

PubMed

Ouyang, Yuhui; Xu, Zhaojun; Fan, Erzhong; Li, Ying; Miyake, Kunio; Xu, Xianyan; Zhang, Luo

2018-04-20

Particulate matter (PM) air pollution has been associated with an increase in the incidence of chronic allergic diseases; however, the mechanisms underlying the effect of exposure to natural ambient air pollution in chronic allergic diseases have not been fully elucidated. In the present study, we aimed to investigate the cellular responses induced by exposure to natural ambient air pollution, employing a mouse model of chronic allergy. The results indicated that exposure to ambient air pollution significantly increased the number of eosinophils in the nasal mucosa. The modulation of gene expression profile identified a set of regulated genes, and the Triggering Receptor Expressed on Myeloid cells1(TREM1) signaling canonical pathway was increased after exposure to ambient air pollution. In vitro, PM2.5 increased Nucleotide-binding oligomerization domain-containing protein 1 (Nod1) and nuclear factor (NF)-κB signaling pathway activation in A549 and HEK293 cell cultures. These results suggest a novel mechanism by which, PM2.5 in ambient air pollution may stimulate the innate immune system through the PM2.5-Nod1-NF-κB axis in chronic allergic disease.

Hypoxia-activated prodrug TH-302 decreased survival rate of canine lymphoma cells under hypoxic condition.

PubMed

Yamazaki, Hiroki; Lai, Yu-Chang; Tateno, Morihiro; Setoguchi, Asuka; Goto-Koshino, Yuko; Endo, Yasuyuki; Nakaichi, Munekazu; Tsujimoto, Hajime; Miura, Naoki

2017-01-01

We tested the hypotheses that hypoxic stimulation enhances growth potentials of canine lymphoma cells by activating hypoxia-inducible factor 1α (HIF-1α), and that the hypoxia-activated prodrug (TH-302) inhibits growth potentials in the cells. We investigated how hypoxic culture affects the growth rate, chemoresistance, and invasiveness of canine lymphoma cells and doxorubicin (DOX)-resistant lymphoma cells, and influences of TH-302 on survival rate of the cells under hypoxic conditions. Our results demonstrated that hypoxic culture upregulated the expression of HIF-1α and its target genes, including ATP-binding cassette transporter B1 (ABCB1), ATP-binding cassette transporter G2 (ABCG2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and survivin, and enhanced the growth rate, DOX resistance, and invasiveness of the cells. Additionally, TH-302 decreased the survival rate of the cells under hypoxic condition. Our studies suggest that hypoxic stimulation may advance the tumorigenicity of canine lymphoma cells, favoring malignant transformation. Therefore, the data presented may contribute to the development of TH-302-based hypoxia-targeting therapies for canine lymphoma.

Tumorigenicity of hypoxic respiring cancer cells revealed by a hypoxia–cell cycle dual reporter

PubMed Central

Le, Anne; Stine, Zachary E.; Nguyen, Christopher; Afzal, Junaid; Sun, Peng; Hamaker, Max; Siegel, Nicholas M.; Gouw, Arvin M.; Kang, Byung-hak; Yu, Shu-Han; Cochran, Rory L.; Sailor, Kurt A.; Song, Hongjun; Dang, Chi V.

2014-01-01

Although aerobic glycolysis provides an advantage in the hypoxic tumor microenvironment, some cancer cells can also respire via oxidative phosphorylation. These respiring (“non-Warburg”) cells were previously thought not to play a key role in tumorigenesis and thus fell from favor in the literature. We sought to determine whether subpopulations of hypoxic cancer cells have different metabolic phenotypes and gene-expression profiles that could influence tumorigenicity and therapeutic response, and we therefore developed a dual fluorescent protein reporter, HypoxCR, that detects hypoxic [hypoxia-inducible factor (HIF) active] and/or cycling cells. Using HEK293T cells as a model, we identified four distinct hypoxic cell populations by flow cytometry. The non-HIF/noncycling cell population expressed a unique set of genes involved in mitochondrial function. Relative to the other subpopulations, these hypoxic “non-Warburg” cells had highest oxygen consumption rates and mitochondrial capacity consistent with increased mitochondrial respiration. We found that these respiring cells were unexpectedly tumorigenic, suggesting that continued respiration under limiting oxygen conditions may be required for tumorigenicity. PMID:25114222

Purinergic modulation of preBötzinger complex inspiratory rhythm in rodents: the interaction between ATP and adenosine

PubMed Central

Zwicker, J D; Rajani, V; Hahn, L B; Funk, G D

2011-01-01

Abstract ATP signalling in the CNS is mediated by a three-part system comprising the actions of ATP (and ADP) at P2 receptors (P2Rs), adenosine (ADO) at P1 receptors (P1Rs), and ectonucleotidases that degrade ATP into ADO. ATP excites preBötzinger complex (preBötC) inspiratory rhythm-generating networks where its release attenuates the hypoxic depression of breathing. Its metabolite, ADO, inhibits breathing through unknown mechanisms that may involve the preBötC. Our objective is to understand the dynamics of this signalling system and its influence on preBötC networks. We show that the preBötC of mouse and rat is sensitive to P2Y1 purinoceptor (P2Y1R) activation, responding with a >2-fold increase in frequency. Remarkably, the mouse preBötC is insensitive to ATP. Only after block of A1 ADORs is the ATP-evoked, P2Y1R-mediated frequency increase observed. This demonstrates that ATP is rapidly degraded to ADO, which activates inhibitory A1Rs, counteracting the P2Y1R-mediated excitation. ADO sensitivity of mouse preBötC was confirmed by a frequency decrease that was absent in rat. Differential ectonucleotidase activities are likely to contribute to the negligible ATP sensitivity of mouse preBötC. Real-time PCR analysis of ectonucleotidase isoforms in preBötC punches revealed TNAP (degrades ATP to ADO) or ENTPDase2 (favours production of excitatory ADP) as the primary constituent in mouse and rat, respectively. These data further establish the sensitivity of this vital network to P2Y1R-mediated excitation, emphasizing that individual components of the three-part signalling system dramatically alter network responses to ATP. Data also suggest therapeutic potential may derive from methods that alter the ATP–ADO balance to favour the excitatory actions of ATP. PMID:21788352

Chronic mild stress facilitates melanoma tumor growth in mouse lines selected for high and low stress-induced analgesia.

PubMed

Ragan, Agnieszka R; Lesniak, Anna; Bochynska-Czyz, Marta; Kosson, Anna; Szymanska, Hanna; Pysniak, Kazimiera; Gajewska, Marta; Lipkowski, Andrzej W; Sacharczuk, Mariusz

2013-09-01

Both chronic stress conditions and hyperergic reaction to environmental stress are known to enhance cancer susceptibility. We described two mouse lines that displayed high (HA) and low (LA) swim stress-induced analgesia (SSIA) to investigate the relationship between inherited differences in sensitivity to stress and proneness to an increased growth rate of subcutaneously inoculated melanoma. These lines display several genetic and physiological differences, among which distinct sensitivity to mutagens and susceptibility to cancer are especially noticeable. High analgesic mice display high proneness both to stress and a rapid local spread of B16F0 melanoma. However, stress-resistant LA mice do not develop melanoma tumors after inoculation, or if so, tumors regress spontaneously. We found that the chronic mild stress (CMS) procedure leads to enhanced interlinear differences in melanoma susceptibility. Tumors developed faster in stress conditions in both lines. However, LA mice still displayed a tendency for spontaneous regression, and 50% of LA mice did not develop a tumor, even under stressed conditions. Moreover, we showed that chronic stress, but not tumor progression, induces depressive behavior, which may be an important clue in cancer therapy. Our results clearly indicate how the interaction between genetic susceptibility to stress and environmental stress determine the risk and progression of melanoma. To our knowledge, HA/LA mouse lines are the first animal models of distinct melanoma progression mediated by inherited differences in stress reactivity.

Hypoxia-induced pulmonary arterial hypertension augments lung injury and airway reactivity caused by ozone exposure

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

Zychowski, Katherine E.; Lucas, Selita N.; Sanchez

Ozone (O{sub 3})-related cardiorespiratory effects are a growing public health concern. Ground level O{sub 3} can exacerbate pre-existing respiratory conditions; however, research regarding therapeutic interventions to reduce O{sub 3}-induced lung injury is limited. In patients with chronic obstructive pulmonary disease, hypoxia-associated pulmonary hypertension (HPH) is a frequent comorbidity that is difficult to treat clinically, yet associated with increased mortality and frequency of exacerbations. In this study, we hypothesized that established HPH would confer vulnerability to acute O{sub 3} pulmonary toxicity. Additionally, we tested whether improvement of pulmonary endothelial barrier integrity via rho-kinase inhibition could mitigate pulmonary inflammation and injury. Tomore » determine if O{sub 3} exacerbated HPH, male C57BL/6 mice were subject to either 3 weeks continuous normoxia (20.9% O{sub 2}) or hypoxia (10.0% O{sub 2}), followed by a 4-h exposure to either 1 ppm O{sub 3} or filtered air (FA). As an additional experimental intervention fasudil (20 mg/kg) was administered intraperitoneally prior to and after O{sub 3} exposures. As expected, hypoxia significantly increased right ventricular pressure and hypertrophy. O{sub 3} exposure in normoxic mice caused lung inflammation but not injury, as indicated by increased cellularity and edema in the lung. However, in hypoxic mice, O{sub 3} exposure led to increased inflammation and edema, along with a profound increase in airway hyperresponsiveness to methacholine. Fasudil administration resulted in reduced O{sub 3}-induced lung injury via the enhancement of pulmonary endothelial barrier integrity. These results indicate that increased pulmonary vascular pressure may enhance lung injury, inflammation and edema when exposed to pollutants, and that enhancement of pulmonary endothelial barrier integrity may alleviate such vulnerability. - Highlights: • Environmental exposures can exacerbate chronic obstructive pulmonary disease (COPD). • It is unknown if comorbid pulmonary hypertension may influence such effects in COPD patients. • Pulmonary hypertension in a mouse model significantly exacerbated ozone-induced lung injury. • Adverse ozone outcomes were largely attenuated by a rho kinase inhibitor, fasudil. • Therapeutic benefit from rho kinase inhibition may be related to endothelial barrier integrity.« less

Measuring oxygen tension modulation, induced by a new pre-radiotherapy therapeutic, in a mammary window chamber mouse model

NASA Astrophysics Data System (ADS)

Schafer, Rachel; Gmitro, Arthur F.

2015-03-01

Tumor regions under hypoxic or low oxygen conditions respond less effectively to many treatment strategies, including radiation therapy. A novel investigational therapeutic, NVX-108 (NuvOx Pharma), has been developed to increase delivery of oxygen through the use of a nano-emulsion of dodecofluoropentane. By raising pO2 levels prior to delivering radiation, treatment efficacy may be improved. To aid in evaluating the novel drug, oxygen tension was quantitatively measured, spatially and temporally, to record the effect of administrating NVX-108 in an orthotopic mammary window chamber mouse model of breast cancer. The oxygen tension was measured through the use of an oxygen-sensitive coating, comprised of phosphorescent platinum porphyrin dye embedded in a polystyrene matrix. The coating, applied to the surface of the coverslip of the window chamber through spin coating, is placed in contact with the mammary fat pad to record the oxygenation status of the surface tissue layer. Prior to implantation of the window chamber, a tumor is grown in the SCID mouse model by injection of MCF-7 cells into the mammary fat pad. Two-dimensional spatial distributions of the pO2 levels were obtained through conversion of measured maps of phosphorescent lifetime. The resulting information on the spatial and temporal variation of the induced oxygen modulation could provide valuable insight into the optimal timing between administration of NVX-108 and radiation treatment to provide the most effective treatment outcome.

[The development of therapeutic vaccine for hepatitis C virus].

PubMed

Kimura, Kiminori; Kohara, Michinori

2012-10-01

Chronic hepatitis C caused by infection with the hepatitis C virus(HCV)is a global health problem. HCV causes persistent infection that can lead to chronic liver diseases such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The therapeutic efficacy of antiviral drugs is not optimal in patients with chronic infection; furthermore, an effective vaccine has not yet been developed. To design an effective HCV vaccine, generation of a convenient animal model of HCV infection is necessary. Recently, we used the Cre/loxP switching system to generate an immunocompetent mouse model of HCV expression, thereby enabling the study of host immune responses against HCV proteins. At present vaccine has not yet been shown to be therapeutically effective against chronic HCV infection. We examined the therapeutic effects of a recombinant vaccinia virus(rVV)encoding HCV protein in a mouse model. we generated rVVs for 3 different HCV proteins and found that one of the recombinant viruses encoding a nonstructural protein(rVV-N25)resolved pathological chronic hepatitis C symptoms in the liver. We propose the possibility that rVV-N25 immunization has the potential for development of an effective therapeutic vaccine for HCV induced chronic hepatitis. The utilization of the therapeutic vaccine can protect progress to chronic hepatitis, and as a consequence, leads to eradication of hepatocellular carcinoma. In this paper, we summarized our current study for HCV therapeutic vaccine and review the vaccine development to date.

Effect of the Discharge Water which Mixed Sewage Disposal Water with Seawater Desalting Treated Sewage for Bottom Sediment and Hypoxic Water Mass

NASA Astrophysics Data System (ADS)

Watanabe, Ryoichi; Yamasaki, Koreyoshi; Minagawa, Tomoko; Iyooka, Hiroki; Kitano, Yoshinori

For every time in summer season, hypoxic water mass has formed at the inner part of Hakata Bay. Field observation study has carried out at the inner part of Hakata Bay since 2004 with the particular aim of tracking the movement of hypoxic water mass. Hypoxic water masses form the end of June to September on this area because the consumption of oxygen in bottom water layers exceeds the re-supply of oxygen from the atmosphere. Under such hypoxic conditions, the seawater desalination plant has begun to use in 2005. After seawater desalination plant operation starting, hypoxic water mass tends to improve. In this research, the authors show the following result. After seawater desalination plant has begun to operate, the hypoxia around the mixed discharge water outlet tends to be improved.

Altered Expression of Middle and Inner Ear Cytokines in Mouse Otitis Media

PubMed Central

MacArthur, Carol J.; Pillers, De-Ann M.; Pang, Jiaqing; Kempton, J. Beth; Trune, Dennis R.

2010-01-01

Objectives/Hypothesis The inner ear is at risk for sensorineural hearing loss in both acute and chronic otitis media (OM), but the underlying mechanisms underlying sensorineural hearing loss are unknown. Previous gene expression array studies showed cytokine genes might be upregulated in the cochleas of mice with acute and chronic otitis media. This implies that the inner ear could manifest a direct inflammatory response to OM that may cause sensorineural damage. Therefore, to better understand inner ear cytokine gene expression during OM, quantitative RT-PCR and immunohistochemistry were performed on mouse models to evaluate middle and inner ear inflammatory and remodeling cytokines. Study Design Basic science experiment. Methods An acute OM model was created in Balb/c mice by a transtympanic injection of S. pneumoniae in one ear; the other ear used as a control. C3H/HeJ mice were screened for unilateral chronic OM with the non-infected ear serving as control. Results Both acute and chronic OM caused both the middle ear and inner tissues in these two mouse models to over express numerous cytokine genes related to tissue remodeling (TNFα, FGF, BMP) and angiogenesis (VEGF), as well as inflammatory cell proliferation (IL-1α,β, IL-2, IL-6). Immunohistochemistry confirmed that both the middle ear and inner ear tissues expressed these cytokines. Conclusion Cochlear tissues are capable of expressing cytokine mRNA that contributes to the inflammation and remodeling that occur in association with middle ear disease. This provides a potential molecular basis for the transient and permanent sensorineural hearing loss often reported with acute and chronic OM. Level of Evidence N/A PMID:21271590

Antioxidants prevent depression of the acute hypoxic ventilatory response by subanaesthetic halothane in men

PubMed Central

Teppema, Luc J; Nieuwenhuijs, Diederik; Sarton, Elise; Romberg, Raymonda; Olievier, Cees N; Ward, Denham S; Dahan, Albert

2002-01-01

We studied the effect of the antioxidants (AOX) ascorbic acid (2 g, I.V.) and α-tocopherol (200 mg, P.O.) on the depressant effect of subanaesthetic doses of halothane (0.11 % end-tidal concentration) on the acute isocapnic hypoxic ventilatory response (AHR), i.e. the ventilatory response upon inhalation of a hypoxic gas mixture for 3 min (leading to a haemoglobin saturation of 82 ± 1.8 %) in healthy male volunteers. In the first set of protocols, two groups of eight subjects each underwent a control hypoxic study, a halothane hypoxic study and finally a halothane hypoxic study after pretreatment with AOX (study 1) or placebo (study 2). Halothane reduced the AHR by more than 50 %, from 0.79 ± 0.31 to 0.36 ± 0.14 l min−1 %−1 in study 1 and from 0.79 ± 0.40 to 0.36 ± 0.19 l min−1 %−1 in study 2, P < 0.01 for both. Pretreatment with AOX prevented this depressant effect of halothane in the subjects of study 1 (AHR returning to 0.77 ± 0.32 l min−1 %−1, n.s. from control), whereas placebo (study 2) had no effect (AHR remaining depressed at 0.36 ± 0.27 l min−1 %−1, P < 0.01 from control). In a second set of protocols, two separate groups of eight subjects each underwent a control hypoxic study, a sham halothane hypoxic study and finally a sham halothane hypoxic study after pretreatment with AOX (study 3) or placebo (study 4). In studies 3 and 4, sham halothane did not modify the control hypoxic response, nor did AOX (study 3) or placebo (study 4). The 95 % confidence intervals for the ratio of hypoxic sensitivities, (AOX + halothane):halothane in study 1 and (AOX - sham halothane):sham halothane in study 3, were [1.7, 2.6] and [1.0, 1.2], respectively. Because the antioxidants prevented the reduction of the acute hypoxic response by halothane, we suggest that this depressant effect may be caused by reactive species produced by a reductive metabolism of halothane during hypoxia or that a change in redox state of carotid body cells by the antioxidants prevented or changed the binding of halothane to its effect site. Our findings may also suggest that reactive species have an inhibiting effect on the acute hypoxic ventilatory response. PMID:12411535

The impairment of learning and memory and synaptic loss in mouse after chronic nitrite exposure.

PubMed

Chen, Yongfang; Cui, Zhanjun; Wang, Lai; Liu, Hongliang; Fan, Wenjuan; Deng, Jinbo; Deng, Jiexin

2016-12-01

The objective of this study is to understand the impairment of learning and memory in mouse after chronic nitrite exposure. The animal model of nitrite exposure in mouse was created with the daily intubation of nitrite in adult healthy male mice for 3 months. Furthermore, the mouse's learning and memory abilities were tested with Morris water maze, and the expression of Synaptophysin and γ-Synuclein was visualized with immunocytochemistry and Western blot. Our results showed that nitrite exposure significantly prolonged the escape latency period (ELP) and decreased the values of the frequency across platform (FAP) as well as the accumulative time in target quadrant (ATITQ) compared to control, in dose-dependent manner. In addition, after nitrite exposure, synaptophysin (SYN) positive buttons in the visual cortex was reduced, in contrast the increase of γ-synuclein positive cells. The results above were supported by Western blot as well. We conclude that nitrite exposure could lead to a decline in mice's learning and memory. The overexpression of γ-synuclein contributed to the synaptic loss, which is most likely the cause of learning and memory impairment. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1720-1730, 2016. © 2015 Wiley Periodicals, Inc.

Curcumin Treatment Improves Motor Behavior in α-Synuclein Transgenic Mice

PubMed Central

Spinelli, Kateri J.; Osterberg, Valerie R.; Meshul, Charles K.; Soumyanath, Amala; Unni, Vivek K.

2015-01-01

The curry spice curcumin plays a protective role in mouse models of neurodegenerative diseases, and can also directly modulate aggregation of α-synuclein protein in vitro, yet no studies have described the interaction of curcumin and α-synuclein in genetic synucleinopathy mouse models. Here we examined the effect of chronic and acute curcumin treatment in the Syn-GFP mouse line, which overexpresses wild-type human α-synuclein protein. We discovered that curcumin diet intervention significantly improved gait impairments and resulted in an increase in phosphorylated forms of α-synuclein at cortical presynaptic terminals. Acute curcumin treatment also caused an increase in phosphorylated α-synuclein in terminals, but had no direct effect on α-synuclein aggregation, as measured by in vivo multiphoton imaging and Proteinase-K digestion. Using LC-MS/MS, we detected ~5 ng/mL and ~12 ng/mL free curcumin in the plasma of chronic or acutely treated mice, with a glucuronidation rate of 94% and 97%, respectively. Despite the low plasma levels and extensive metabolism of curcumin, these results show that dietary curcumin intervention correlates with significant behavioral and molecular changes in a genetic synucleinopathy mouse model that mimics human disease. PMID:26035833

Age specific effect of MK-801 on hypoxic body temperature regulation in rats.

PubMed

Baig, Mirza Shafiulla; Joseph, Vincent

2008-02-01

Hypoxic exposure produces a consistent decrease of rectal temperature (Tb), which is recognized as a potent protective response. While some of the neural mechanisms underlying this response have recently been described, it remains poorly known how these mechanisms evolve during post-natal development. We recently reported that in rat pups NMDA glutamate receptor limits Tb drop upon hypoxic exposure, an effect that has not been reported by others in adult rats. Accordingly, we tested the hypothesis that the implication of NMDA receptors on temperature control during hypoxic exposure evolves during development. To this aim, we evaluated the hypoxic (30 min - 12% O(2)) responses of Tb, metabolic rate, and ventilation in rats after injection of vehicle, or the NMDA receptor antagonist MK-801, at different ages (post-natal days 4, 10, 20 and 2-3 month-old - P4, P10, P20 and P60). MK-801 amplified the magnitude of the hypoxic-induced Tb drop in P4, P10 and P20 rats, but this effect was not apparent in adults. In P20 rats MK-801 tripled the hypoxic induced Tb drop, which was 0.5 degrees C in control and 1.4 degrees C in treated rats (p<0.0001). This effect was specific to temperature regulation, and was not accompanied by similar changes of other recorded parameters. MK-801 induced a significant decrease of the hypoxic ventilatory response in adults only. We conclude that NMDA glutamate receptor acts as a counter-regulatory factor that limits the hypoxic-induced drop of rectal temperature during post-natal development in rats.

Human umbilical vein endothelial cells protect against hypoxic-ischemic damage in neonatal brain via stromal cell-derived factor 1/C-X-C chemokine receptor type 4.

PubMed

Wu, Chia-Ching; Chen, Yi-Chi; Chang, Ying-Chao; Wang, Lan-Wan; Lin, Yung-Chieh; Chiang, Yi-Lun; Ho, Chien-Jung; Huang, Chao-Ching

2013-05-01

Agents that protect against neurovascular damage provide a powerful neuroprotective strategy. Human umbilical vein endothelial cells (HUVECs) may be used to treat neonates with hypoxic-ischemia (HI) because of its autologous capability. We hypothesized that peripherally injected HUVECs entered the brain after HI, protected against neurovascular damage, and provided protection via stromal cell-derived factor 1/C-X-C chemokine receptor type 4 pathway in neonatal brain. Postpartum day 7 rat pups received intraperitoneal injections of low-passage HUVEC-P4, high-passage HUVEC-P8, or conditioned medium before and immediately after HI. HUVECs were transfected with adenovirus-green fluorescent protein for cell tracing. Oxygen-glucose deprivation was established by coculturing HUVEC-P4 with mouse neuroblastoma neuronal cells (Neuro-2a) and with mouse immortalized cerebral vascular endothelial cells (b.End3). HUVEC-P4-treated group had more blood levels of green fluorescent protein-positive cells than HUVEC-P8-treated group 3 hours postinjection. Intraperitoneally injected HUVEC-P4, but not HUVEC-P8, entered the cortex after HI and positioned closed to the neurons and microvessels. Compared with the condition medium-treated group, the HUVEC-P4-treated but not the HUVEC-P8-treated group showed significantly less neuronal apoptosis and blood-brain barrier damage and more preservation of microvessels in the cortex 24 hours after HI. On postpartum day 14, the HUVEC-P4-treated group showed significant neuroprotection compared with the condition medium-treated group. Stromal cell-derived factor 1 was upregulated in the ipsilateral cortex 3 hours after HI, and inhibiting the stromal cell-derived factor 1/C-X-C chemokine receptor type 4 reduced the protective effect of HUVEC-P4. In vitro transwell coculturing of HUVEC-P4 also significantly protected against oxygen-glucose deprivation cell death in neurons and endothelial cells. Cell therapy using HUVECs may provide a powerful therapeutic strategy in treating neonates with HI.

Simple platform for chronic imaging of hippocampal activity during spontaneous behaviour in an awake mouse

PubMed Central

Villette, Vincent; Levesque, Mathieu; Miled, Amine; Gosselin, Benoit; Topolnik, Lisa

2017-01-01

Chronic electrophysiological recordings of neuronal activity combined with two-photon Ca2+ imaging give access to high resolution and cellular specificity. In addition, awake drug-free experimentation is required for investigating the physiological mechanisms that operate in the brain. Here, we developed a simple head fixation platform, which allows simultaneous chronic imaging and electrophysiological recordings to be obtained from the hippocampus of awake mice. We performed quantitative analyses of spontaneous animal behaviour, the associated network states and the cellular activities in the dorsal hippocampus as well as estimated the brain stability limits to image dendritic processes and individual axonal boutons. Ca2+ imaging recordings revealed a relatively stereotyped hippocampal activity despite a high inter-animal and inter-day variability in the mouse behavior. In addition to quiet state and locomotion behavioural patterns, the platform allowed the reliable detection of walking steps and fine speed variations. The brain motion during locomotion was limited to ~1.8 μm, thus allowing for imaging of small sub-cellular structures to be performed in parallel with recordings of network and behavioural states. This simple device extends the drug-free experimentation in vivo, enabling high-stability optophysiological experiments with single-bouton resolution in the mouse awake brain. PMID:28240275

Impaired acclimatization to chronic hypoxia in adult male and female rats following neonatal hypoxia.

PubMed

Lumbroso, Delphine; Joseph, Vincent

2009-08-01

We tested the hypothesis that neonatal exposure to hypoxia alters acclimatization to chronic hypoxia later in life. Rat pups were exposed to normobaric hypoxia (12% O(2); nHx group) in a sealed chamber, or to normoxia (21% O(2); nNx group) from the day before birth to postnatal day 10. The animals were then raised in normal conditions until reaching 12 wk of age. At this age, we assessed ventilatory and hematological acclimatization to chronic hypoxia by exposing male and female nHx and nNx rats for 2 wk to 10% O(2). Minute ventilation, metabolic rate, hypoxic ventilatory response, hematocrit, and hemoglobin levels were measured both before and after acclimatization. We also quantified right ventricular hypertrophy as an index of pulmonary hypertension both before and after acclimatization. There was a significant effect of neonatal hypoxia that decreases ventilatory response (relative to metabolic rate, VE/VCO(2)) to acute hypoxia before acclimatization in males but not in females. nHx rats had an impaired acclimatization to chronic hypoxia characterized by altered respiratory pattern and elevated hematocrit and hemoglobin levels after acclimatization, in both males and females. Right ventricular hypertrophy was present before and after acclimatization in nHx rats, indicating that neonatal hypoxia results in pulmonary hypertension in adults. We conclude that neonatal hypoxia impairs acclimatization to chronic hypoxia in adults and may be a factor contributing to the establishment of chronic mountain sickness in humans living at high altitude.

Nitric oxide-mediated vasodilation becomes independent of β-adrenergic receptor activation with increased intensity of hypoxic exercise

PubMed Central

Curry, Timothy B.; Wilkins, Brad W.; Joyner, Michael J.

2011-01-01

Hypoxic vasodilation in skeletal muscle at rest is known to include β-adrenergic receptor-stimulated nitric oxide (NO) release. We previously reported that the augmented skeletal muscle vasodilation during mild hypoxic forearm exercise includes β-adrenergic mechanisms. However, it is unclear whether a β-adrenergic receptor-stimulated NO component exists during hypoxic exercise. We hypothesized that NO-mediated vasodilation becomes independent of β-adrenergic receptor activation with increased exercise intensity during hypoxic exercise. Ten subjects (7 men, 3 women; 23 ± 1 yr) breathed hypoxic gas to titrate arterial O2 saturation to 80% while remaining normocapnic. Subjects performed two consecutive bouts of incremental rhythmic forearm exercise (10% and 20% of maximum) with local administration (via a brachial artery catheter) of propranolol (β-adrenergic receptor inhibition) alone and with the combination of propranolol and nitric oxide synthase inhibition [NG-monomethyl-l-arginine (l-NMMA)] under normoxic and hypoxic conditions. Forearm blood flow (FBF, ml/min; Doppler ultrasound) and blood pressure [mean arterial pressure (MAP), mmHg; brachial artery catheter] were assessed, and forearm vascular conductance (FVC, ml·min−1·100 mmHg−1) was calculated (FBF/MAP). During propranolol alone, the rise in FVC (Δ from normoxic baseline) due to hypoxic exercise was 217 ± 29 and 415 ± 41 ml·min−1·100 mmHg−1 (10% and 20% of maximum, respectively). Combined propranolol-l-NMMA infusion during hypoxic exercise attenuated ΔFVC at 20% (352 ± 44 ml·min−1·100 mmHg−1; P < 0.001) but not at 10% (202 ± 28 ml·min−1·100 mmHg−1; P = 0.08) of maximum compared with propranolol alone. These data, when integrated with earlier findings, demonstrate that NO contributes to the compensatory vasodilation during mild and moderate hypoxic exercise; a β-adrenergic receptor-stimulated NO component exists during low-intensity hypoxic exercise. However, the source of the NO becomes less dependent on β-adrenergic mechanisms as exercise intensity increases. PMID:21193565

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells

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

Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4–5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba{sup 2+}-sensitive inward rectifier K{sup +} current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level butmore » not at mRNA level after the hypoxic culture. Ca{sup 2+} imaging study revealed that the hypoxic stress enhanced store-operated Ca{sup 2+} (SOC) entry, which was significantly reduced in the presence of 100 μM Ba{sup 2+}. On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba{sup 2+}. We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca{sup 2+} entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. -- Highlights: •Hypoxic culture of brain endothelial cells (BEC) caused membrane hyperpolarization. •This hyperpolarization was due to the increased expression of Kir2.1 channels. •Hypoxia enhanced store-operated Ca{sup 2+} (SOC) entry via Kir2.1 up-regulation. •Expression levels of putative SOC channels were not affected by hypoxia. •Kir2.1 up-regulation is responsible for hypoxia-enhanced BEC proliferation.« less

Rhabdomyolysis, acute renal failure, and cardiac arrest secondary to status dystonicus in a child with glutaric aciduria type I.

PubMed

Jamuar, Saumya S; Newton, Stephanie A; Prabhu, Sanjay P; Hecht, Leah; Costas, Karen C; Wessel, Ann E; Harris, David J; Anselm, Irina; Berry, Gerard T

2012-08-01

An 8-½ year old boy with glutaric aciduria type I (GA1) and chronic dystonia presented with severe rhabdomyolysis in association with a febrile illness. His clinical course was complicated by acute renal failure, cardiac arrest and hypoxic ischemic encephalopathy. As acute neurological decompensation is typically not seen in patients with GA1 beyond early childhood, this case report serves as an important reminder that patients with GA1 and status dystonicus may be at risk for acute life-threatening rhabdomyolysis, renal failure and further neurological injury at any age. Copyright © 2012 Elsevier Inc. All rights reserved.

Myricetin suppresses UVB-induced wrinkle formation and MMP-9 expression by inhibiting Raf

PubMed Central

Jung, Sung Keun; Lee, Ki Won; Kim, Ho Young; Oh, Mi Hyun; Byun, Sanguine; Lim, Sung Hwan; Heo, Yong-Seok; Kang, Nam Joo; Bode, Ann M.; Dong, Zigang; Lee, Hyong Joo

2010-01-01

Chronic exposure to solar ultraviolet (UV) light causes skin photoaging. Many studies have shown that naturally occurring phytochemicals have anti-photoaging effects, but their direct target molecule(s) and mechanism(s) remain unclear. We found that myricetin, a major flavonoid in berries and red wine, inhibited wrinkle formation in mouse skin induced by chronic UVB irradiation (0.18 J/cm2, 3 days/wk for 15 wk). Myricetin treatment reduced UVB-induced epidermal thickening of mouse skin and also suppressed UVB-induced matrix metalloproteinase-9 (MMP-9) protein expression and enzyme activity. Myricetin appeared to exert its anti-aging effects by suppressing UVB-induced Raf kinase activity and subsequent attenuation of UVB-induced phosphorylation of MEK and ERK in mouse skin. In vitro and in vivo pull-down assays revealed that myricetin bound with Raf in an ATP-noncompetitive manner. Overall, these results indicate that myricetin exerts potent anti-photoaging activity by regulating MMP-9 expression through the suppression of Raf kinase activity. PMID:20093107

Platelet ERK5 is a Redox Switch and Triggers Maladaptive Platelet Responses and Myocardial Infarct Expansion

PubMed Central

Cameron, Scott J.; Ture, Sara K.; Mickelsen, Deanne; Chakrabarti, Enakshi; Modjeski, Kristina L.; McNitt, Scott; Seaberry, Micheal; Field, David J.; Le, Nhat-Tu; Abe, Jun-ichi; Morrell, Craig N.

2015-01-01

Background Platelets have a pathophysiologic role in the ischemic microvascular environment of acute coronary syndromes (ACS). Compared to platelet activation in normal healthy conditions, less attention is given to mechanisms of platelet activation in diseased states. Platelet function and mechanisms of activation in ischemic and reactive oxygen species (ROS) rich environments may not be the same as in normal healthy conditions. Extracellular Regulated Protein Kinase 5 (ERK5) is a Mitogen Activated Protein Kinase (MAPK) family member activated in hypoxic, ROS rich environments, and in response to receptor signaling mechanisms. Prior studies suggest a protective effect of ERK5 in endothelial and myocardial cells following ischemia. We present evidence that platelets express ERK5 and platelet ERK5 has an adverse effect on platelet activation via selective receptor-dependent and receptor-independent ROS mediated mechanisms in ischemic myocardium. Methods and Results Using isolated human platelets and a mouse model of myocardial infarction (MI), we found that platelet ERK5 is activated post-MI and platelet specific ERK5−/− mice have less platelet activation, reduced MI size, and improved post-MI heart function. Furthermore, the expression of downstream ERK5 regulated proteins is reduced in ERK5−/− platelets post-MI. Conclusions ERK5 functions as a platelet activator in ischemic conditions and platelet ERK5 maintains the expression of some platelet proteins following MI, leading to infarct expansion. This demonstrates that platelet function in normal healthy conditions is different from platelet function in chronic ischemic and inflammatory conditions. Platelet ERK5 may be a target for acute therapeutic intervention in the thrombotic and inflammatory post-MI environment. PMID:25934838

Protection from cyanide-induced brain injury by the Nrf2 transcriptional activator carnosic acid.

PubMed

Zhang, Dongxian; Lee, Brian; Nutter, Anthony; Song, Paul; Dolatabadi, Nima; Parker, James; Sanz-Blasco, Sara; Newmeyer, Traci; Ambasudhan, Rajesh; McKercher, Scott R; Masliah, Eliezer; Lipton, Stuart A

2015-06-01

Cyanide is a life-threatening, bioterrorist agent, preventing cellular respiration by inhibiting cytochrome c oxidase, resulting in cardiopulmonary failure, hypoxic brain injury, and death within minutes. However, even after treatment with various antidotes to protect cytochrome oxidase, cyanide intoxication in humans can induce a delayed-onset neurological syndrome that includes symptoms of Parkinsonism. Additional mechanisms are thought to underlie cyanide-induced neuronal damage, including generation of reactive oxygen species. This may account for the fact that antioxidants prevent some aspects of cyanide-induced neuronal damage. Here, as a potential preemptive countermeasure against a bioterrorist attack with cyanide, we tested the CNS protective effect of carnosic acid (CA), a pro-electrophilic compound found in the herb rosemary. CA crosses the blood-brain barrier to up-regulate endogenous antioxidant enzymes via activation of the Nrf2 transcriptional pathway. We demonstrate that CA exerts neuroprotective effects on cyanide-induced brain damage in cultured rodent and human-induced pluripotent stem cell-derived neurons in vitro, and in vivo in various brain areas of a non-Swiss albino mouse model of cyanide poisoning that simulates damage observed in the human brain. Cyanide, a potential bioterrorist agent, can produce a chronic delayed-onset neurological syndrome that includes symptoms of Parkinsonism. Here, cyanide poisoning treated with the proelectrophillic compound carnosic acid, results in reduced neuronal cell death in both in vitro and in vivo models through activation of the Nrf2/ARE transcriptional pathway. Carnosic acid is therefore a potential treatment for the toxic central nervous system (CNS) effects of cyanide poisoning. ARE, antioxidant responsive element; Nrf2 (NFE2L2, Nuclear factor (erythroid-derived 2)-like 2). © 2015 International Society for Neurochemistry.

Microsensor and transcriptomic signatures of oxygen depletion in biofilms associated with chronic wounds.

PubMed

James, Garth A; Ge Zhao, Alice; Usui, Marcia; Underwood, Robert A; Nguyen, Hung; Beyenal, Haluk; deLancey Pulcini, Elinor; Agostinho Hunt, Alessandra; Bernstein, Hans C; Fleckman, Philip; Olerud, John; Williamson, Kerry S; Franklin, Michael J; Stewart, Philip S

2016-03-01

Biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms and by the responding leukocytes, may impede wound healing by depleting the oxygen that is required for healing. In this study, oxygen microsensors to measure oxygen transects through in vitro cultured biofilms, biofilms formed in vivo within scabs from a diabetic (db/db) mouse wound model, and ex vivo human chronic wound specimens was used. The results showed that oxygen levels within mouse scabs had steep gradients that reached minima ranging from 17 to 72 mmHg on live mice and from 6.4 to 1.1 mmHg on euthanized mice. The oxygen gradients in the mouse scabs were similar to those observed for clinical isolates cultured in vitro and for human ex vivo specimens. To characterize the metabolic activities of the bacteria in the mouse scabs, transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds was performed. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results also indicated that the bacteria within the wounds experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results supported the hypothesis that bacterial biofilms in chronic wounds promote chronicity by contributing to the maintenance of localized low oxygen tensions, through their metabolic activities and through their recruitment of cells that consume oxygen for host defensive processes. © 2016 by the Wound Healing Society.

Chronic Anatabine Treatment Reduces Alzheimer’s Disease (AD)-Like Pathology and Improves Socio-Behavioral Deficits in a Transgenic Mouse Model of AD

PubMed Central

Verma, Megha; Beaulieu-Abdelahad, David; Ait-Ghezala, Ghania; Li, Rena; Crawford, Fiona; Mullan, Michael; Paris, Daniel

2015-01-01

Anatabine is a minor tobacco alkaloid, which is also found in plants of the Solanaceae family and displays a chemical structure similarity with nicotine. We have shown previously that anatabine displays some anti-inflammatory properties and reduces microgliosis and tau phosphorylation in a pure mouse model of tauopathy. We therefore investigated the effects of a chronic oral treatment with anatabine in a transgenic mouse model (Tg PS1/APPswe) of Alzheimer’s disease (AD) which displays pathological Aβ deposits, neuroinflammation and behavioral deficits. In the elevated plus maze, Tg PS1/APPswe mice exhibited hyperactivity and disinhibition compared to wild-type mice. Six and a half months of chronic oral anatabine treatment, suppressed hyperactivity and disinhibition in Tg PS1/APPswe mice compared to Tg PS1/APPswe receiving regular drinking water. Tg PS1/APPswe mice also elicited profound social interaction and social memory deficits, which were both alleviated by the anatabine treatment. We found that anatabine reduces the activation of STAT3 and NFκB in the vicinity of Aβ deposits in Tg PS1/APPswe mice resulting in a reduction of the expression of some of their target genes including Bace1, iNOS and Cox-2. In addition, a significant reduction in microgliosis and pathological deposition of Aβ was observed in the brain of Tg PS1/APPswe mice treated with anatabine. This is the first study to investigate the impact of chronic anatabine treatment on AD-like pathology and behavior in a transgenic mouse model of AD. Overall, our data show that anatabine reduces β-amyloidosis, neuroinflammation and alleviates some behavioral deficits in Tg PS1/APPswe, supporting further exploration of anatabine as a possible disease modifying agent for the treatment of AD. PMID:26010758

Systemic administration of thrombin peptide TP508 enhances VEGF-stimulated angiogenesis and attenuates effects of chronic hypoxia

PubMed Central

Olszewska-Pazdrak, Barbara; Carney, Darrell H.

2015-01-01

Revascularization of chronic wounds and ischemic tissue is attenuated by endothelial dysfunction and the inability of angiogenic factors to stimulate angiogenesis. We recently showed that TP508, a nonproteolytic thrombin peptide, increases perfusion and NO-dependent vasodilation in hearts with chronic ischemia and stimulates NO production by endothelial cells. In this study, we investigated systemic in vivo effects of TP508 on VEGF-stimulated angiogenesis in vitro using aortic explants in normoxic and hypoxic conditions. Mice were injected with saline or TP508 and 24h later aortas were removed and cultured to quantify endothelial sprouting. TP508 injection increased endothelial sprouting and potentiated the in vitro response to VEGF. Exposure of control explants to hypoxia inhibited basal and VEGF-stimulated endothelial cell sprouting. This effect of hypoxia was significantly prevented by TP508 injection. Thus, TP508 systemic administration increases responsiveness of aortic endothelial cells to VEGF and diminishes the effect of chronic hypoxia on endothelial cell sprouting. Studies using human endothelial cells in culture suggest that protective effects of TP508 during hypoxia may involve stimulation of endothelial cell NO production. These data suggest potential clinical benefit of using a combination of systemic TP508 and local VEGF as a therapy for revascularization of ischemic tissue. PMID:23594718

Cycling hypoxia: A key feature of the tumor microenvironment.

PubMed

Michiels, Carine; Tellier, Céline; Feron, Olivier

2016-08-01

A compelling body of evidence indicates that most human solid tumors contain hypoxic areas. Hypoxia is the consequence not only of the chaotic proliferation of cancer cells that places them at distance from the nearest capillary but also of the abnormal structure of the new vasculature network resulting in transient blood flow. Hence two types of hypoxia are observed in tumors: chronic and cycling (intermittent) hypoxia. Most of the current work aims at understanding the role of chronic hypoxia in tumor growth, response to treatment and metastasis. Only recently, cycling hypoxia, with spatial and temporal fluctuations in oxygen levels, has emerged as another key feature of the tumor environment that triggers different responses in comparison to chronic hypoxia. Either type of hypoxia is associated with distinct effects not only in cancer cells but also in stromal cells. In particular, cycling hypoxia has been demonstrated to favor, to a higher extent than chronic hypoxia, angiogenesis, resistance to anti-cancer treatments, intratumoral inflammation and tumor metastasis. These review details these effects as well as the signaling pathway it triggers to switch on specific transcriptomic programs. Understanding the signaling pathways through which cycling hypoxia induces these processes that support the development of an aggressive cancer could convey to the emergence of promising new cancer treatments. Copyright © 2016 Elsevier B.V. All rights reserved.

Using the endocannabinoid system as a neuroprotective strategy in perinatal hypoxic-ischemic brain injury

PubMed Central

Lara-Celador, I.; Goñi-de-Cerio, F.; Alvarez, Antonia; Hilario, Enrique

2013-01-01

One of the most important causes of brain injury in the neonatal period is a perinatal hypoxic-ischemic event. This devastating condition can lead to long-term neurological deficits or even death. After hypoxic-ischemic brain injury, a variety of specific cellular mechanisms are set in motion, triggering cell damage and finally producing cell death. Effective therapeutic treatments against this phenomenon are still unavailable because of complex molecular mechanisms underlying hypoxic-ischemic brain injury. After a thorough understanding of the mechanism underlying neural plasticity following hypoxic-ischemic brain injury, various neuroprotective therapies have been developed for alleviating brain injury and improving long-term outcomes. Among them, the endocannabinoid system emerges as a natural system of neuroprotection. The endocannabinoid system modulates a wide range of physiological processes in mammals and has demonstrated neuroprotective effects in different paradigms of acute brain injury, acting as a natural neuroprotectant. The aim of this review is to study the use of different therapies to induce long-term therapeutic effects after hypoxic-ischemic brain injury, and analyze the important role of the endocannabinoid system as a new neuroprotective strategy against perinatal hypoxic-ischemic brain injury. PMID:25206720

[Effect of progesterone on the expression of GLUT in the brain following hypoxic-ischemia in newborn rats].

PubMed

Li, Dong-Liang; Han, Hua

2008-08-01

To investigate the expression of GLUT1 and GLUT3 in the hippocampus after cerebral hypoxic-ischemia (HI) in newborn rats and the effect of progesterone (PROG) on them. Forty newborn SD rats were randomly divided into four groups: normal group, sham-operated group, hypoxic-ischemic group and progesterone group. Model of hypoxic-ischemia encephalopathy (HIE) was established in the 7-day-old newborn SD rats. Immunohistochemical method was applied to detect the expression of GLUT1 and GLUT3 in hippocampus. GLUT1 and GLUT3 were slightly seen in normal and sham operation group, there was no obviously difference between the two groups (P > 0.05). The expression of GLUT1 and GLUT3 in hypoxic-ischemia group were all higher than that in sham operated group (P < 0.05). Not only the expression of GLUT in progesterone group were significantly higher than that in sham operated group (P < 0.01), but also than that in hypoxic-ischemia group (P < 0.05). PROG could increase the tolerance of neuron to hypoxic-ischemia with maintaining the energy supply in the brain by up-regulating GLUT expression.

Pretreatment with magnesium sulfate attenuates white matter damage by preventing cell death of developing oligodendrocytes.

PubMed

Seyama, Takahiro; Kamei, Yoshimasa; Iriyama, Takayuki; Imada, Shinya; Ichinose, Mari; Toshimitsu, Masatake; Fujii, Tomoyuki; Asou, Hiroaki

2018-04-01

Antenatal maternal administration of magnesium sulfate (MgSO 4 ) reduces cerebral palsy in preterm infants. However, it remains controversial as to whether it also reduces occurrence of white matter damage, or periventricular leukomalacia. We assessed the effect of MgSO 4 against white matter damage induced by hypoxic-ischemic insult using a neonatal rat model and culture of premyelinating oligodendrocytes (pre-OL). Rat pups at postnatal day (P) 6 were administered either MgSO 4 or vehicle intraperitoneally before hypoxic-ischemic insult (unilateral ligation of the carotid artery followed by 6% oxygen for 1 h). The population of oligodendrocyte (OL) markers and CD-68-positive microglia at P11, and TdT-mediated biotin-16-dUTP nick-end labeling (TUNEL)-positive cells at P8 were evaluated in pericallosal white matter. Primary cultures of mouse pre-OL were subjected to oxygen glucose deprivation condition, and the lactate dehydrogenase release from culture cells was evaluated to assess cell viability. Pretreatment with MgSO 4 attenuated the loss of OL markers, such as myelin basic protein and Olig2, in ipsilateral pericallosal white matter and decreased the number of CD-68-positive microglia and TUNEL-positive cells in vivo. Pretreatment with MgSO 4 also inhibited lactate dehydrogenase release from pre-OL induced by oxygen glucose deprivation in vitro. Pretreatment with MgSO 4 attenuates white matter damage by preventing cell death of pre-OL. © 2018 Japan Society of Obstetrics and Gynecology.

Destruction of a distal hypoxia response element abolishes trans-activation of the PAG1 gene mediated by HIF-independent chromatin looping.

PubMed

Schörg, Alexandra; Santambrogio, Sara; Platt, James L; Schödel, Johannes; Lindenmeyer, Maja T; Cohen, Clemens D; Schrödter, Katrin; Mole, David R; Wenger, Roland H; Hoogewijs, David

2015-07-13

A crucial step in the cellular adaptation to oxygen deficiency is the binding of hypoxia-inducible factors (HIFs) to hypoxia response elements (HREs) of oxygen-regulated genes. Genome-wide HIF-1α/2α/β DNA-binding studies revealed that the majority of HREs reside distant to the promoter regions, but the function of these distal HREs has only been marginally studied in the genomic context. We used chromatin immunoprecipitation (ChIP), gene editing (TALEN) and chromosome conformation capture (3C) to localize and functionally characterize a 82 kb upstream HRE that solely drives oxygen-regulated expression of the newly identified HIF target gene PAG1. PAG1, a transmembrane adaptor protein involved in Src signalling, was hypoxically induced in various cell lines and mouse tissues. ChIP and reporter gene assays demonstrated that the -82 kb HRE regulates PAG1, but not an equally distant gene further upstream, by direct interaction with HIF. Ablation of the consensus HRE motif abolished the hypoxic induction of PAG1 but not general oxygen signalling. 3C assays revealed that the -82 kb HRE physically associates with the PAG1 promoter region, independent of HIF-DNA interaction. These results demonstrate a constitutive interaction between the -82 kb HRE and the PAG1 promoter, suggesting a physiologically important rapid response to hypoxia. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Children with chronic lung diseases have cognitive dysfunction as assessed by event-related potential (auditory P300) and Stanford-Binet IQ (SB-IV) test.

PubMed

Kamel, Terez Boshra; Abd Elmonaem, Mahmoud Tarek; Khalil, Lobna Hamed; Goda, Mona Hamdy; Sanyelbhaa, Hossam; Ramzy, Mourad Alfy

2016-10-01

Chronic lung disease (CLD) in children represents a heterogeneous group of many clinico-pathological entities with risk of adverse impact of chronic or intermittent hypoxia. So far, few researchers have investigated the cognitive function in these children, and the role of auditory P300 in the assessment of their cognitive function has not been investigated yet. This study was designed to assess the cognitive functions among schoolchildren with different chronic pulmonary diseases using both auditory P300 and Stanford-Binet test. This cross-sectional study included 40 school-aged children who were suffering from chronic chest troubles other than asthma and 30 healthy children of similar age, gender and socioeconomic state as a control group. All subjects were evaluated through clinical examination, radiological evaluation and spirometry. Audiological evaluation included (basic otological examination, pure-tone, speech audiometry and immittancemetry). Cognitive function was assessed by auditory P300 and psychological evaluation using Stanford-Binet test (4th edition). Children with chronic lung diseases had significantly lower anthropometric measures compared to healthy controls. They had statistically significant lower IQ scores and delayed P300 latencies denoting lower cognitive abilities. Cognitive dysfunction correlated to severity of disease. P300 latencies were prolonged among hypoxic patients. Cognitive deficits in children with different chronic lung diseases were best detected using both Stanford-Binet test and auditory P300. P300 is an easy objective tool. P300 is affected early with hypoxia and could alarm subtle cognitive dysfunction.

The Influence of Changes in Tumor Hypoxia on Dose-Painting Treatment Plans Based on {sup 18}F-FMISO Positron Emission Tomography

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

Lin Zhixiong; Mechalakos, James; Nehmeh, Sadek

2008-03-15

Purpose: To evaluate how changes in tumor hypoxia, according to serial fluorine-18-labeled fluoro-misonidazole ({sup 18}F-FMISO) positron emission tomography (PET) imaging, affect the efficacy of intensity-modulated radiotherapy (IMRT) dose painting. Methods and Materials: Seven patients with head and neck cancers were imaged twice with FMISO PET, separated by 3 days, before radiotherapy. Intensity-modulated radiotherapy plans were designed, on the basis of the first FMISO scan, to deliver a boost dose of 14 Gy to the hypoxic volume, in addition to the 70-Gy prescription dose. The same plans were then applied to hypoxic volumes from the second FMISO scan, and the efficacymore » of dose painting evaluated by assessing coverage of the hypoxic volumes using D{sub max}, D{sub min}, D{sub mean}, D{sub 95}, and equivalent uniform dose (EUD). Results: Similar hypoxic volumes were observed in the serial scans for 3 patients but dissimilar ones for the other 4. There was reduced coverage of hypoxic volumes of the second FMISO scan relative to that of the first scan (e.g., the average EUD decreased from 87 Gy to 80 Gy). The decrease was dependent on the similarity of the hypoxic volumes of the two scans (e.g., the average EUD decrease was approximately 4 Gy for patients with similar hypoxic volumes and approximately 12 Gy for patients with dissimilar ones). Conclusions: The changes in spatial distribution of tumor hypoxia, as detected in serial FMISO PET imaging, compromised the coverage of hypoxic tumor volumes achievable by dose-painting IMRT. However, dose painting always increased the EUD of the hypoxic volumes.« less

Hyperadditive Ventilatory Response Arising from Interaction between the Carotid Chemoreflex and the Muscle Mechanoreflex in Healthy Humans.

PubMed

Silva, Talita M; Aranda, Liliane C; Paula-Ribeiro, Marcelle; Oliveira, Diogo M; Medeiros, Wladimir Musetti; Vianna, Lauro C; Nery, Luiz E; Silva, Bruno M

2018-03-22

Physical exercise potentiates the carotid chemoreflex control of ventilation (VE). Hyperadditive neural interactions may partially mediate the potentiation. However, some neural interactions remain incompletely explored. As the potentiation occurs even during low-intensity exercise, we tested the hypothesis that the carotid chemoreflex and the muscle mechanoreflex could interact in a hyperadditive fashion. Fourteen young healthy subjects inhaled, randomly, in separate visits, 12% O 2 to stimulate the carotid chemoreflex, and 21% O 2 as control. A rebreathing circuit maintained isocapnia. During gases administration, subjects either remained at rest (i.e., normoxic and hypoxic rest) or the muscle mechanoreflex was stimulated, via passive knee movement (i.e., normoxic and hypoxic movement). Surface muscle electrical activity did not increase during the passive movement, confirming the absence of active contractions. Hypoxic rest and normoxic movement similarly increased VE [change (mean {plus minus} SEM) = 1.24 {plus minus} 0.72 vs. 0.73 {plus minus} 0.43 L/min, respectively; P = 0.46], but hypoxic rest only increased tidal volume (Vt) and normoxic movement only increased breathing frequency (BF). Hypoxic movement induced greater VE and mean inspiratory flow (Vt/Ti) increase than the sum of hypoxic rest and normoxic movement isolated responses (VE change: hypoxic movement = 3.72 {plus minus} 0.81 vs. sum = 1.96 {plus minus} 0.83 L/min, P = 0.01; Vt/Ti change: hypoxic movement = 0.13 {plus minus} 0.03 vs. sum = 0.06 {plus minus} 0.03 L/s, P = 0.02). Moreover, hypoxic movement increased both Vt and BF. Collectively, the results indicate the carotid chemoreflex and the muscle mechanoreflex interacted mediating a hyperadditive ventilatory response in healthy humans.

Effects of Hypoxia on the Phylogenetic Composition and Species Distribution of Protists in a Subtropical Harbor.

PubMed

Rocke, Emma; Jing, Hongmei; Xia, Xiaomin; Liu, Hongbin

2016-07-01

Tolo Harbor, a subtropical semi-enclosed coastal water body, is surrounded by an expanding urban community, which contributes to large concentrations of nutrient runoff, leading to algal blooms and localized hypoxic episodes. Present knowledge of protist distributions in subtropical waters during hypoxic conditions is very limited. In this study, therefore, we combined parallel 454 pyrosequencing technology and denaturing gradient gel electrophoresis (DGGE) fingerprint analyses to reveal the protist community shifts before, during, and after a 2-week hypoxic episode during the summer of 2011. Hierarchical clustering for DGGE demonstrated similar grouping of hypoxic samples separately from oxic samples. Dissolved oxygen (DO) concentration and dissolved inorganic nitrogen:phosphate (DIN:PO4) concentrations significantly affected OTU distribution in 454 sequenced samples, and a shift toward a ciliate and marine alveolate clade II (MALV II) species composition occurred as waters shifted from oxic to hypoxic. These results suggest that protist community shifts toward heterotrophic and parasitic tendencies as well as decreased diversity and richness in response to hypoxic outbreaks.

Chronic unpredictable stress decreases expression of brain-derived neurotrophic factor (BDNF) in mouse ovaries: relationship to oocytes developmental potential.

PubMed

Wu, Li-Min; Hu, Mei-Hong; Tong, Xian-Hong; Han, Hui; Shen, Ni; Jin, Ren-Tao; Wang, Wei; Zhou, Gui-Xiang; He, Guo-Ping; Liu, Yu-Sheng

2012-01-01

Brain-derived neurotropic factor (BDNF) was originally described in the nervous system but has been shown to be expressed in ovary tissues recently, acting as a paracrine/autocrine regulator required for developments of follicles and oocytes. Although it is generally accepted that chronic stress impairs female reproduction and decreases the expression of BDNF in limbic structures of central nervous system, which contributes to mood disorder. However, it is not known whether chronic stress affects oocytes developments, nor whether it affects expression of BDNF in ovary. Mice were randomly assigned into control group, stressed group, BDNF-treated group and BDNF-treated stressed group. The chronic unpredictable mild stress model was used to produce psychosocial stress in mice, and the model was verified by open field test and hypothalamic-pituitary-adrenal (HPA) axis activity. The methods of immunohistochemistry and western blotting were used to detect BDNF protein level and distribution. The number of retrieved oocytes, oocyte maturation, embryo cleavage and the rates of blastocyst formation after parthenogenetic activation were evaluated. Chronic unpredictable stress decreased the BDNF expression in antral follicles, but didn't affect the BDNF expression in primordial, primary and secondary follicles. Chronic unpredictable stress also decreased the number of retrieved oocytes and the rate of blastocyst formation, which was rescued by exogenous BDNF treatment. BDNF in mouse ovaries may be related to the decreased number of retrieved oocytes and impaired oocytes developmental potential induced by chronic unpredictable stress.

Chronic Unpredictable Stress Decreases Expression of Brain-Derived Neurotrophic Factor (BDNF) in Mouse Ovaries: Relationship to Oocytes Developmental Potential

PubMed Central

Tong, Xian-Hong; Han, Hui; Shen, Ni; Jin, Ren-Tao; Wang, Wei; Zhou, Gui-Xiang; He, Guo-Ping; Liu, Yu-Sheng

2012-01-01

Background Brain-derived neurotropic factor (BDNF) was originally described in the nervous system but has been shown to be expressed in ovary tissues recently, acting as a paracrine/autocrine regulator required for developments of follicles and oocytes. Although it is generally accepted that chronic stress impairs female reproduction and decreases the expression of BDNF in limbic structures of central nervous system, which contributes to mood disorder. However, it is not known whether chronic stress affects oocytes developments, nor whether it affects expression of BDNF in ovary. Methods Mice were randomly assigned into control group, stressed group, BDNF-treated group and BDNF-treated stressed group. The chronic unpredictable mild stress model was used to produce psychosocial stress in mice, and the model was verified by open field test and hypothalamic-pituitary-adrenal (HPA) axis activity. The methods of immunohistochemistry and western blotting were used to detect BDNF protein level and distribution. The number of retrieved oocytes, oocyte maturation, embryo cleavage and the rates of blastocyst formation after parthenogenetic activation were evaluated. Results Chronic unpredictable stress decreased the BDNF expression in antral follicles, but didn’t affect the BDNF expression in primordial, primary and secondary follicles. Chronic unpredictable stress also decreased the number of retrieved oocytes and the rate of blastocyst formation, which was rescued by exogenous BDNF treatment. Conclusion BDNF in mouse ovaries may be related to the decreased number of retrieved oocytes and impaired oocytes developmental potential induced by chronic unpredictable stress. PMID:23284991

Genetically Engineered Mouse Models for Studying Inflammatory Bowel Disease

PubMed Central

Mizoguchi, Atsushi; Takeuchi, Takahito; Himuro, Hidetomo; Okada, Toshiyuki; Mizoguchi, Emiko

2015-01-01

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition that is mediated by very complex mechanisms controlled by genetic, immune, and environmental factors. More than 74 kinds of genetically engineered mouse strains have been established since 1993 for studying IBD. Although mouse models cannot fully reflect human IBD, they have provided significant contributions for not only understanding the mechanism, but also developing new therapeutic means for IBD. Indeed, 20 kinds of genetically engineered mouse models carry the susceptibility genes identified in human IBD, and the functions of some other IBD susceptibility genes have also been dissected out using mouse models. Cutting-edge technologies such as cell-specific and inducible knockout systems, which were recently employed to mouse IBD models, have further enhanced the ability of investigators to provide important and unexpected rationales for developing new therapeutic strategies for IBD. In this review article, we briefly introduce 74 kinds of genetically engineered mouse models that spontaneously develop intestinal inflammation. PMID:26387641

GENE EXPRESSION PROFILING OF MOUSE SKIN AND PAPILLOMAS FOLLOWING CHRONIC EXPOSURE TO MONOMETHYLARSONOUS ACID IN K6/ODC TRANSGENIC MICE

EPA Science Inventory

Methylarsonous acid [MMA(III)], a common metabolite of inorganic arsenic metabolism, increases tumor frequency in the skin of K6/ODC transgenic mice following a chronic exposure. To characterize gene expression profiles predictive of MMA(III) exposure and mode of action of carcin...

A novel mouse model identifies cooperating mutations and therapeutic targets critical for chronic myeloid leukemia progression

PubMed Central

Giotopoulos, George; van der Weyden, Louise; Osaki, Hikari; Rust, Alistair G.; Gallipoli, Paolo; Meduri, Eshwar; Horton, Sarah J.; Chan, Wai-In; Foster, Donna; Prinjha, Rab K.; Pimanda, John E.; Tenen, Daniel G.; Vassiliou, George S.; Koschmieder, Steffen; Adams, David J.

2015-01-01

The introduction of highly selective ABL-tyrosine kinase inhibitors (TKIs) has revolutionized therapy for chronic myeloid leukemia (CML). However, TKIs are only efficacious in the chronic phase of the disease and effective therapies for TKI-refractory CML, or after progression to blast crisis (BC), are lacking. Whereas the chronic phase of CML is dependent on BCR-ABL, additional mutations are required for progression to BC. However, the identity of these mutations and the pathways they affect are poorly understood, hampering our ability to identify therapeutic targets and improve outcomes. Here, we describe a novel mouse model that allows identification of mechanisms of BC progression in an unbiased and tractable manner, using transposon-based insertional mutagenesis on the background of chronic phase CML. Our BC model is the first to faithfully recapitulate the phenotype, cellular and molecular biology of human CML progression. We report a heterogeneous and unique pattern of insertions identifying known and novel candidate genes and demonstrate that these pathways drive disease progression and provide potential targets for novel therapeutic strategies. Our model greatly informs the biology of CML progression and provides a potent resource for the development of candidate therapies to improve the dismal outcomes in this highly aggressive disease. PMID:26304963

Inflammatory Response Mechanisms Exacerbating Hypoxemia in Coexistent Pulmonary Fibrosis and Sleep Apnea

PubMed Central

Balachandran, Jay

2015-01-01

Mediators of inflammation, oxidative stress, and chemoattractants drive the hypoxemic mechanisms that accompany pulmonary fibrosis. Patients with idiopathic pulmonary fibrosis commonly have obstructive sleep apnea, which potentiates the hypoxic stimuli for oxidative stress, culminating in systemic inflammation and generalized vascular endothelial damage. Comorbidities like pulmonary hypertension, obesity, gastroesophageal reflux disease, and hypoxic pulmonary vasoconstriction contribute to chronic hypoxemia leading to the release of proinflammatory cytokines that may propagate clinical deterioration and alter the pulmonary fibrotic pathway. Tissue inhibitor of metalloproteinase (TIMP-1), interleukin- (IL-) 1α, cytokine-induced neutrophil chemoattractant (CINC-1, CINC-2α/β), lipopolysaccharide induced CXC chemokine (LIX), monokine induced by gamma interferon (MIG-1), macrophage inflammatory protein- (MIP-) 1α, MIP-3α, and nuclear factor- (NF-) κB appear to mediate disease progression. Adipocytes may induce hypoxia inducible factor (HIF) 1α production; GERD is associated with increased levels of lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and tumor necrosis factor alpha (TNF-α); pulmonary artery myocytes often exhibit increased cytosolic free Ca2+. Protein kinase C (PKC) mediated upregulation of TNF-α and IL-1β also occurs in the pulmonary arteries. Increased understanding of the inflammatory mechanisms driving hypoxemia in pulmonary fibrosis and obstructive sleep apnea may potentiate the identification of appropriate therapeutic targets for developing effective therapies. PMID:25944985

Developmental plasticity of mitochondrial function in American alligators, Alligator mississippiensis

PubMed Central

Crossley, Janna; Elsey, Ruth M.; Dzialowski, Edward M.; Shiels, Holly A.; Crossley, Dane A.

2016-01-01

The effect of hypoxia on cellular metabolism is well documented in adult vertebrates, but information is entirely lacking for embryonic organisms. The effect of hypoxia on embryonic physiology is particularly interesting, as metabolic responses during development may have life-long consequences, due to developmental plasticity. To this end, we investigated the effects of chronic developmental hypoxia on cardiac mitochondrial function in embryonic and juvenile American alligators (Alligator mississippiensis). Alligator eggs were incubated in 21% or 10% oxygen from 20 to 90% of embryonic development. Embryos were either harvested at 90% development or allowed to hatch and then reared in 21% oxygen for 3 yr. Ventricular mitochondria were isolated from embryonic/juvenile alligator hearts. Mitochondrial respiration and enzymatic activities of electron transport chain complexes were measured with a microrespirometer and spectrophotometer, respectively. Developmental hypoxia induced growth restriction and increased relative heart mass, and this phenotype persisted into juvenile life. Embryonic mitochondrial function was not affected by developmental hypoxia, but at the juvenile life stage, animals from hypoxic incubations had lower levels of Leak respiration and higher respiratory control ratios, which is indicative of enhanced mitochondrial efficiency. Our results suggest developmental hypoxia can have life-long consequences for alligator morphology and metabolic function. Further investigations are necessary to reveal the adaptive significance of the enhanced mitochondrial efficiency in the hypoxic phenotype. PMID:27707718

Persisting in papyrus: size, oxidative stress, and fitness in freshwater organisms adapted to sustained hypoxia.

PubMed

Joyner-Matos, Joanna; Chapman, Lauren J

2013-08-01

Aquatic hypoxia is generally viewed as stressful for aerobic organisms. However, hypoxia may also benefit organisms by decreasing cellular stress, particularly that related to free radicals. Thus, an ideal habitat may have the minimum O2 necessary to both sustain aerobic metabolism and reduce the need to scavenge free radicals and repair free radical damage. The ability of aquatic organisms to sustain aerobic metabolism relates in part to the ability to maximize gas diffusion, which can be facilitated by small body size when O2 uptake occurs across the body surface, by a large gill surface area, or by the ability to use atmospheric air. We use water-breathing organisms in chronically hypoxic papyrus (Cyperus papyrus) swamps of East Africa to test the hypothesis that cellular-level benefits of hypoxia may translate into increased fitness, especially for small organisms. A review of recent studies of fingernail clams (Sphaerium sp.) shows that clams living in sustained hypoxia have minimized oxidative stress and that these cellular-level benefits may lead to increased fitness. We suggest that organisms in the extreme conditions in the papyrus swamps provide a unique opportunity to challenge the conventional classification of hypoxic habitats as 'stressful' and normoxic habitats as 'optimal.' Copyright © 2013 Elsevier Inc. All rights reserved.

Pharmacological models and approaches for pathophysiological conditions associated with hypoxia and oxidative stress.

PubMed

Farías, Jorge G; Herrera, Emilio A; Carrasco-Pozo, Catalina; Sotomayor-Zárate, Ramón; Cruz, Gonzalo; Morales, Paola; Castillo, Rodrigo L

2016-02-01

Hypoxia is the failure of oxygenation at the tissue level, where the reduced oxygen delivered is not enough to satisfy tissue demands. Metabolic depression is the physiological adaptation associated with reduced oxygen consumption, which evidently does not cause any harm to organs that are exposed to acute and short hypoxic insults. Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability of endogenous antioxidant systems to scavenge ROS, where ROS overwhelms the antioxidant capacity. Oxidative stress plays a crucial role in the pathogenesis of diseases related to hypoxia during intrauterine development and postnatal life. Thus, excessive ROS are implicated in the irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Here, we describe several pathophysiological conditions and in vivo and ex vivo models developed for the study of hypoxic and oxidative stress injury. We reviewed existing literature on the responses to hypoxia and oxidative stress of the cardiovascular, renal, reproductive, and central nervous systems, and discussed paradigms of chronic and intermittent hypobaric hypoxia. This systematic review is a critical analysis of the advantages in the application of some experimental strategies and their contributions leading to novel pharmacological therapies. Copyright © 2015 Elsevier Inc. All rights reserved.

Studies on cerebral protection of digoxin against hypoxic-ischemic brain damage in neonatal rats.

PubMed

Peng, Kaiwei; Tan, Danfeng; He, Miao; Guo, Dandan; Huang, Juan; Wang, Xia; Liu, Chentao; Zheng, Xiangrong

2016-08-17

Hypoxic-ischemic brain damage (HIBD) is a major cause of neonatal acute deaths and chronic nervous system damage. Our present study was designed to investigate the possible neuroprotective effect of digoxin-induced pharmacological preconditioning after hypoxia-ischemia and underlying mechanisms. Neonatal rats were assigned randomly to control, HIBD, or HIBD+digoxin groups. Pharmacological preconditioning was induced by administration of digoxin 72 h before inducing HIBD by carotid occlusion+hypoxia. Behavioral assays, and neuropathological and apoptotic assessments were performed to examine the effects; the expression of Na/K ATPase was also assessed. Rats in the HIBD group showed deficiencies on the T-maze, radial water maze, and postural reflex tests, whereas the HIBD+digoxin group showed significant improvements on all behavioral tests. The rats treated with digoxin showed recovery of pathological conditions, increased number of neural cells and proliferative cells, and decreased number of apoptotic cells. Meanwhile, an increased expression level of Na/K ATPase was observed after digoxin preconditioning treatment. The preconditioning treatment of digoxin contributed toward an improved functional recovery and exerted a marked neuroprotective effect including promotion of cell proliferation and reduction of apoptosis after HIBD, and the neuroprotective action was likely associated with increased expression of Na/K ATPase.

Effect of acute hypoxic shock on the rat brain morphology and tripeptidyl peptidase I activity.

PubMed

Petrova, Emilia B; Dimitrova, Mashenka B; Ivanov, Ivaylo P; Pavlova, Velichka G; Dimitrova, Stella G; Kadiysky, Dimitar S

2016-06-01

Hypoxic events are known to cause substantial damage to the hippocampus, cerebellum and striatum. The impact of hypoxic shock on other brain parts is not sufficiently studied. Recent studies show that tripeptidyl peptidase I (TPPI) activity in fish is altered after a hypoxic stress pointing out at a possible enzyme involvement in response to hypoxia. Similar studies are not performed in mammals. In this work, the effect of sodium nitrite-induced acute hypoxic shock on the rat brain was studied at different post-treatment periods. Morphological changes in cerebral cortex, cerebellum, medulla oblongata, thalamus, mesencephalon and pons were assessed using silver-copper impregnation for neurodegeneration. TPPI activity was biochemically assayed and localized by enzyme histochemistry. Although less vulnerable to oxidative stress, the studied brain areas showed different histopathological changes, such as neuronal loss and tissue vacuolization, dilatation of the smallest capillaries and impairment of neuronal processes. TPPI activity was strictly regulated following the hypoxic stress. It was found to increase 12-24h post-treatment, then decreased followed by a slow process of recovery. The enzyme histochemistry revealed a temporary enzyme deficiency in all types of neurons. These findings indicate a possible involvement of the enzyme in rat brain response to hypoxic stress. Copyright © 2016 Elsevier GmbH. All rights reserved.

Ethyl pyruvate inhibits hypoxic pulmonary vasoconstriction and attenuates pulmonary artery cytokine expression

PubMed Central

Tsai, Ben M.; Lahm, Tim; Morrell, Eric D.; Crisostomo, Paul R.; Markel, Troy; Wang, Meijing; Meldrum, Daniel R.

2009-01-01

Hypoxic pulmonary vasoconstriction is a common consequence of acute lung injury and may be mediated by increased local production of proinflammatory cytokines. Ethyl pyruvate is a novel anti-inflammatory agent that has been shown to downregulate proinflammatory genes following hemorrhagic shock; however, its effects on hypoxic pulmonary vasoconstriction are unknown. We hypothesized that ethyl pyruvate would inhibit hypoxic pulmonary vasoconstriction and downregulate pulmonary artery cytokine expression during hypoxia. To study this, isometric force displacement was measured in isolated rat pulmonary artery rings (n=8/group) during hypoxia (95% N2/5% CO2) with or without prior ethyl pyruvate (10 mM) treatment. Following 60 minutes of hypoxia, pulmonary artery rings were analyzed for TNF-α and IL-1 mRNA via RT-PCR. Ethyl pyruvate inhibited hypoxic pulmonary artery contraction (4.49±2.32% vs. 88.80±5.68% hypoxia alone) and attenuated the hypoxic upregulation of pulmonary artery TNF and IL-1 mRNA (p<0.05). These data indicate that: 1) hypoxia increases pulmonary artery vasoconstriction and proinflammatory cytokine gene expression; 2) ethyl pyruvate decreases hypoxic pulmonary vasoconstriction and downregulates hypoxia-induced pulmonary artery proinflammatory cytokine gene expression; and 3) ethyl pyruvate may represent a novel therapeutic adjunct in the treatment of acute lung injury. PMID:17574585

Involvement of SIRT1 in hypoxic down-regulation of c-Myc and β-catenin and hypoxic preconditioning effect of polyphenols

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

Hong, Kyung-Soo; Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan; Park, Jun-Ik

2012-03-01

SIRT1 has been found to function as a Class III deacetylase that affects the acetylation status of histones and other important cellular nonhistone proteins involved in various cellular pathways including stress responses and apoptosis. In this study, we investigated the role of SIRT1 signaling in the hypoxic down-regulations of c-Myc and β-catenin and hypoxic preconditioning effect of the red wine polyphenols such as piceatannol, myricetin, quercetin and resveratrol. We found that the expression of SIRT1 was significantly increased in hypoxia-exposed or hypoxic preconditioned HepG2 cells, which was closely associated with the up-regulation of HIF-1α and down-regulation of c-Myc and β-cateninmore » expression via deacetylation of these proteins. In addition, blockade of SIRT1 activation using siRNA or amurensin G, a new potent SIRT1 inhibitor, abolished hypoxia-induced HIF-1α expression but increased c-Myc and β-catenin expression. SIRT1 was also found to stabilize HIF-1α protein and destabilize c-Myc, β-catenin and PHD2 under hypoxia. We also found that myricetin, quercetin, piceatannol and resveratrol up-regulated HIF-1α and down-regulated c-Myc, PHD2 and β-catenin expressions via SIRT1 activation, in a manner that mimics hypoxic preconditioning. This study provides new insights of the molecular mechanisms of hypoxic preconditioning and suggests that polyphenolic SIRT1 activators could be used to mimic hypoxic/ischemic preconditioning. -- Graphical abstract: Polyphenols mimicked hypoxic preconditioning by up-regulating HIF-1α and SIRT1 and down-regulating c-Myc, PHD2, and β-catenin. HepG2 cells were pretreated with the indicated doses of myricetin (MYR; A), quercetin (QUR; B), or piceatannol (PIC; C) for 4 h and then exposed to hypoxia for 4 h. Levels of HIF-1α, SIRT1, c-Myc, β-catenin, and PHD2 were determined by western blot analysis. The data are representative of three individual experiments. Highlights: ► SIRT1 expression is increased in hypoxia-exposed or hypoxic preconditioned cells. ► SIRT1 deacetylates c-Myc and β-catenin ► HIF-1α is up-regulated by down-regulation of c-Myc and β-catenin expression. ► Polyphenolic SIRT1 activators mimics hypoxic preconditioning.« less

Cardioprotection induced in a mouse model of neuropathic pain via anterior nucleus of paraventricular thalamus.

PubMed

Cheng, Yi-Fen; Chang, Ya-Ting; Chen, Wei-Hsin; Shih, Hsi-Chien; Chen, Yen-Hui; Shyu, Bai-Chuang; Chen, Chien-Chang

2017-10-10

Myocardial infarction is the leading cause of death worldwide. Restoration of blood flow rescues myocardium but also causes ischemia-reperfusion injury. Here, we show that in a mouse model of chronic neuropathic pain, ischemia-reperfusion injury following myocardial infarction is reduced, and this cardioprotection is induced via an anterior nucleus of paraventricular thalamus (PVA)-dependent parasympathetic pathway. Pharmacological inhibition of extracellular signal-regulated kinase activation in the PVA abolishes neuropathic pain-induced cardioprotection, whereas activation of PVA neurons pharmacologically, or optogenetic stimulation, is sufficient to induce cardioprotection. Furthermore, neuropathic injury and optogenetic stimulation of PVA neurons reduce the heart rate. These results suggest that the parasympathetic nerve is responsible for this unexpected cardioprotective effect of chronic neuropathic pain in mice.Various forms of preconditioning can prevent ischemic-reperfusion injury after myocardial infarction. Here, the authors show that in mice, the presence of chronic neuropathic pain can have a cardioprotective effect, and that this is dependent on neural activation in the paraventricular thalamus.

[Analgesic effect of ferulic acid on CCI mice: behavior and neurobiological analysis].

PubMed

Lv, Wei-Hong; Zhang, Lu; Wu, Shu-Juan; Chen, Sai-Zhen; Zhu, Xin-Bo; Pan, Jian-Chun

2013-11-01

To study the analgesic effect of chronic administration with ferulic acid, and preliminarily discuss its mechanism. Thermal hyperalgesia and mechanical allodynia tests were conducted to observe the analgesic effect of chronic administration with ferulic acid on CCI mice. The neurochemical detection method was applied to observe the effect chronic administration with ferulic acid on monoamine neurotransmitter and monoamine oxidase activity. Compared with the normal group, CCI mice showed notable reduction in heat sensation and nociceptive threshold in and mechanical allodynia. Ferulic acid (10, 20, 40 and 80 mg x kg(-1), po) could significantly reverse the situations. In an in-depth study, we found that the reason for these results was that ferulic acid was dose-dependent in increasing 5-HT and NE levels in hippocampus, frontal cortex and amygdale and could inhibit MAO-A activity in mouse brains. These results showed that ferulic acid has the analgesic effect. Its mechanism may be related to the inhibition of monoamine oxidase activity and the increase in monoamine neurotransmitter in mouse brains.

Bidirectional signalling between EphA2 and ephrinA1 increases tubular cell attachment, laminin secretion and modulates erythropoietin expression after renal hypoxic injury.

PubMed

Rodriguez, Stéphane; Rudloff, Stefan; Koenig, Katrin Franziska; Karthik, Swapna; Hoogewijs, David; Huynh-Do, Uyen

2016-08-01

Acute kidney injury (AKI) is common in hospitalized patients and has a poor prognosis, the severity of AKI being linked to progression to chronic kidney disease. This stresses the need to search for protective mechanisms during the acute phase. We investigated kidney repair after hypoxic injury using a rat model of renal artery branch ligation, which led to an oxygen gradient vertical to the corticomedullary axis. Three distinct zones were observed: tubular necrosis, infarction border zone and preserved normal tissue. EphA2 is a receptor tyrosine kinase with pivotal roles in cell architecture, migration and survival, upon juxtacrine contact with its membrane-bound ligand EphrinA1. Following hypoxia, EphA2 was up-regulated in cortical and medullary tubular cells, while EphrinA1 was up-regulated in interstitial cells adjacent to peritubular capillaries. Moreover, erythropoietin (EPO) messenger RNA (mRNA) was strongly expressed in the border zone of infarcted kidney within the first 6 h. To gain more insight into the biological impact of EphA2 and EphrinA1 up-regulation, we activated the signalling pathways in vitro using recombinant EphrinA1/Fc or EphA2/Fc proteins. Stimulation of EphA2 forward signalling in the proximal tubular cell line HK2 increased cell attachment and laminin secretion at the baso-lateral side. Conversely, activation of reverse signalling through EphrinA1 expressed by Hep3B cells promoted EPO production at both the transcriptional and protein level. Strikingly, in co-culture experiments, juxtacrine contact between EphA2 expressing MDCK and EphrinA1 expressing Hep3B was sufficient to induce a significant up-regulation of EPO mRNA production in the latter cells, even in the absence of hypoxic conditions. The synergistic effects of EphA2 and hypoxia led to a 15-20-fold increase of EPO expression. Collectively, our results suggest an important role of EphA2/EphrinA1 signalling in kidney repair after hypoxic injury through stimulation of (i) tubular cell attachment, (ii) secretion of basal membrane proteins and (iii) EPO production. These findings could thus pave the way to new therapeutic approaches.

Cell sheet engineering using the stromal vascular fraction of adipose tissue as a vascularization strategy.

PubMed

Costa, Marina; Cerqueira, Mariana T; Santos, Tírcia C; Sampaio-Marques, Belém; Ludovico, Paula; Marques, Alexandra P; Pirraco, Rogério P; Reis, Rui L

2017-06-01

Current vascularization strategies for Tissue Engineering constructs, in particular cell sheet-based, are limited by time-consuming and expensive endothelial cell isolation and/or by the complexity of using extrinsic growth factors. Herein, we propose an alternative strategy using angiogenic cell sheets (CS) obtained from the stromal vascular fraction (SVF) of adipose tissue that can be incorporated into more complex constructs. Cells from the SVF were cultured in normoxic and hypoxic conditions for up to 8days in the absence of extrinsic growth factors. Immunocytochemistry against CD31 and CD146 revealed spontaneous organization in capillary-like structures, more complex after hypoxic conditioning. Inhibition of HIF-1α pathway hindered capillary-like structure formation in SVF cells cultured in hypoxia, suggesting a role of HIF-1α. Moreover, hypoxic SVF cells showed a trend for increased secretion of angiogenic factors, which was reflected in increased network formation by endothelial cells cultured on matrigel using that conditioned medium. In vivo implantation of SVF CS in a mouse hind limb ischemia model revealed that hypoxia-conditioned CS led to improved restoration of blood flow. Both in vitro and in vivo data suggest that SVF CS can be used as simple and cost-efficient tools to promote functional vascularization of TE constructs. Neovascularization after implantation is a major obstacle for producing clinically viable cell sheet-based tissue engineered constructs. Strategies using endothelial cells and extrinsic angiogenic growth factors are expensive and time consuming and may raise concerns of tumorigenicity. In this manuscript, we describe a simplified approach using angiogenic cell sheets fabricated from the stromal vascular fraction of adipose tissue. The strong angiogenic behavior of these cell sheets, achieved without the use of external growth factors, was further stimulated by low oxygen culture. When implanted in an in vivo model of hind limb ischemia, the angiogenic cell sheets contributed to blood flux recovery. These cell sheets can therefore be used as a straightforward tool to increase the neovascularization of cell sheet-based thick constructs. Copyright © 2017. Published by Elsevier Ltd.

THE INDUCTION OF HEPATOCELLULAR NEOPLASIA BY TRICHLOROACETIC ACID ADMINISTERED IN THE DRINKING WATER OF THE MALE B6C3F1 MOUSE

EPA Science Inventory

Summary What is the study? The study is a chronic bioassay (2 years) of trichloroacetic acid, a drinking water disinfection by-product, in the male B6C3F1 mouse.
What is the impact to the field and the Agency?
The impact of this study will derive from the use of...

Detection of hypoxic fractions in murine tumors by comet assay: Comparison with other techniques

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

Hu, Q.; Kavanagh, M.C.; Newcombe, D.

1995-12-01

The alkaline comet assay was used to detect the hypoxic fractions of murine tumors. A total of four tumor types were tested using needle aspiration biopsies taken immediately after a radiation dose of 15 Gy. Initial studies confirmed that the normalized tail moment, a parameter reflecting single-strand DNA breaks induced by the radiation, was linearly related to radiation dose. Further, it was shown that for a mixed population (1:1) of cells irradiated under air-breathing or hypoxic conditions, the histogram of normal tail moment values obtained from analyzing 400 cells in the population had a double peak which, when fitted withmore » two Gaussian distributions, gave a good estimate of the proportion of the two subpopulations. For the four tumor types, the means of the calculated hypoxic fractions from four or five individual tumors were 0.15 {+-} 0.04 for B16F1, 0.08 {+-} 0.04 for KHT-LP1, 0.17 {+-} 0.04 for RIF-1 and 0.04 {+-} 0.01 for SCCVII. Analysis of variance showed that the hypoxic fraction in KHT-LP1 tumors is significantly lower than those of the other three tumors (P = 0.026) but that there is no significant difference in hypoxic fraction between B16F1, RIF-1 and SCCVII tumors (P = 0.574). Results from multiple samples taken from each of five RIF-1 tumors showed that the intertumor heterogeneity of hypoxic fractions was greater than that within the same tumor. The mean hypoxic fraction obtained using the comet assay for the four tumor types was compared with the hypoxic fraction determined by the clonogenic assay, or median pO{sub 2} values, or [{sup 3}H]misonidazole binding in the same tumor types. The values of hypoxic fraction obtained with the comet assay were two to four times lower than those measured by the paired survival method. Preliminary results obtained with a dose of 5 Gy were consistent with those obtained using 15 Gy. These results suggest the further development of the comet assay for clinical studies. 21 refs., 7 figs., 5 tabs.« less

Hypoxic exosomes facilitate bladder tumor growth and development through transferring long non-coding RNA-UCA1.

PubMed

Xue, Mei; Chen, Wei; Xiang, An; Wang, Ruiqi; Chen, He; Pan, Jingjing; Pang, Huan; An, Hongli; Wang, Xiang; Hou, Huilian; Li, Xu

2017-08-25

To overcome the hostile hypoxic microenvironment of solid tumors, tumor cells secrete a large number of non-coding RNA-containing exosomes that facilitate tumor development and metastasis. However, the precise mechanisms of tumor cell-derived exosomes during hypoxia are unknown. Here, we aim to clarify whether hypoxia affects tumor growth and progression by transferring long non-coding RNA-urothelial cancer-associated 1 (lncRNA-UCA1) enriched exosomes secreted from bladder cancer cells. We used bladder cancer 5637 cells with high expression of lncRNA-UCA1 as exosome-generating cells and bladder cancer UMUC2 cells with low expression of lncRNA-UCA1 as recipient cells. Exosomes derived from 5637 cells cultured under normoxic or hypoxic conditions were isolated and identified by transmission electron microscopy, nanoparticle tracking analysis and western blotting analysis. These exosomes were co-cultured with UMUC2 cells to evaluate cell proliferation, migration and invasion. We further investigated the roles of exosomal lncRNA-UCA1 derived from hypoxic 5637 cells by xenograft models. The availability of lncRNA-UCA1 in serum-derived exosomes as a biomarker for bladder cancer was also assessed. We found that hypoxic exosomes derived from 5637 cells promoted cell proliferation, migration and invasion, and hypoxic exosomal RNAs could be internalized by three bladder cancer cell lines. Importantly, lncRNA-UCA1 was secreted in hypoxic 5637 cell-derived exosomes. Compared with normoxic exosomes, hypoxic exosomes derived from 5637 cells showed the higher expression levels of lncRNA-UCA1. Moreover, Hypoxic exosomal lncRNA-UCA1 could promote tumor growth and progression though epithelial-mesenchymal transition, in vitro and in vivo. In addition, the expression levels of lncRNA-UCA1 in the human serum-derived exosomes of bladder cancer patients were higher than that in the healthy controls. Together, our results demonstrate that hypoxic bladder cancer cells remodel tumor microenvironment to facilitate tumor growth and development though secreting the oncogenic lncRNA-UCA1-enriched exosomes and exosomal lncRNA-UCA1 in human serum has the possibility as a diagnostic biomarker for bladder cancer.

The novel KMO inhibitor CHDI-340246 leads to a restoration of electrophysiological alterations in mouse models of Huntington's disease.

PubMed

Beaumont, Vahri; Mrzljak, Ladislav; Dijkman, Ulrike; Freije, Robert; Heins, Mariette; Rassoulpour, Arash; Tombaugh, Geoffrey; Gelman, Simon; Bradaia, Amyaouch; Steidl, Esther; Gleyzes, Melanie; Heikkinen, Taneli; Lehtimäki, Kimmo; Puoliväli, Jukka; Kontkanen, Outi; Javier, Robyn M; Neagoe, Ioana; Deisemann, Heike; Winkler, Dirk; Ebneth, Andreas; Khetarpal, Vinod; Toledo-Sherman, Leticia; Dominguez, Celia; Park, Larry C; Munoz-Sanjuan, Ignacio

2016-08-01

Dysregulation of the kynurenine (Kyn) pathway has been associated with the progression of Huntington's disease (HD). In particular, elevated levels of the kynurenine metabolites 3-hydroxy kynurenine (3-OH-Kyn) and quinolinic acid (Quin), have been reported in the brains of HD patients as well as in rodent models of HD. The production of these metabolites is controlled by the activity of kynurenine mono-oxygenase (KMO), an enzyme which catalyzes the synthesis of 3-OH-Kyn from Kyn. In order to determine the role of KMO in the phenotype of mouse models of HD, we have developed a potent and selective KMO inhibitor termed CHDI-340246. We show that this compound, when administered orally to transgenic mouse models of HD, potently and dose-dependently modulates the Kyn pathway in peripheral tissues and in the central nervous system. The administration of CHDI-340246 leads to an inhibition of the formation of 3-OH-Kyn and Quin, and to an elevation of Kyn and Kynurenic acid (KynA) levels in brain tissues. We show that administration of CHDI-340246 or of Kyn and of KynA can restore several electrophysiological alterations in mouse models of HD, both acutely and after chronic administration. However, using a comprehensive panel of behavioral tests, we demonstrate that the chronic dosing of a selective KMO inhibitor does not significantly modify behavioral phenotypes or natural progression in mouse models of HD. Copyright © 2016. Published by Elsevier Inc.

Regulation of breathing and body temperature of a burrowing rodent during hypoxic-hypercapnia.

PubMed

Barros, Renata C H; Abe, Augusto S; Cárnio, Evelin C; Branco, Luiz G S

2004-05-01

Burrowing mammals usually have low respiratory sensitivity to hypoxia and hypercapnia. However, the interaction between ventilation (V), metabolism and body temperature (Tb) during hypoxic-hypercapnia has never been addressed. We tested the hypothesis that Clyomys bishopi, a burrowing rodent of the Brazilian cerrado, shows a small ventilatory response to hypoxic-hypercapnia, accompanied by a marked drop in Tb and metabolism. V, Tb and O(2) consumption (V?O(2)) of C. bishopi were measured during exposure to air, hypoxia (10% and 7% O(2)), hypercapnia (3% and 5% CO(2)) and hypoxic-hypercapnia (10% O(2)+ 3% CO(2)). Hypoxia of 7% but not 10%, caused a significant increase in V, and a significant drop in Tb. Both hypoxic levels decreased V?O(2) and 7% O(2) significantly increased V/V?O(2). Hypercapnia of 5%, but not 3%, elicited a significant increase in V, although no significant change in Tb, V?O(2) or V/V?O(2) was detected. A combination of 10% O(2) and 3% CO(2) had minor effects on V and Tb, while V?O(2) decreased and V/V?O(2) tended to increase. We conclude that C. bishopi has a low sensitivity not only to hypoxia and hypercapnia, but also to hypoxic-hypercapnia, manifested by a biphasic ventilatory response, a drop in metabolism and a tendency to increase V/V?O(2). The effect of hypoxic-hypercapnia was the summation of the hypoxia and hypercapnia effects, with respiratory responses tending to have hypercapnic patterns while metabolic responses, hypoxic patterns.

Hypoxic events and concomitant factors in preterm infants on non-invasive ventilation.

PubMed

Fathabadi, Omid Sadeghi; Gale, Timothy; Wheeler, Kevin; Plottier, Gemma; Owen, Louise S; Olivier, J C; Dargaville, Peter A

2017-04-01

Automated control of inspired oxygen for newborn infants is an emerging technology, currently limited by reliance on a single input signal (oxygen saturation, SpO 2 ). This is while other signals that may herald the onset of hypoxic events or identify spurious hypoxia are not usually utilised. We wished to assess the frequency of apnoea, loss of circuit pressure and/or motion artefact in proximity to hypoxic events in preterm infants on non-invasive ventilation. Hypoxic events (SpO 2  < 80 %) were identified using a previously acquired dataset obtained from preterm infants receiving non-invasive ventilation. Events with concomitant apnoea, loss of circuit pressure or oximetry motion artefact were annotated, and the frequency of each of these factors was determined. The effect of duration and timing of apnoea on the characteristics of the associated hypoxic events was studied. Among 1224 hypoxic events, 555 (45 %) were accompanied by apnoea, 31 (2.5 %) by loss of circuit pressure and 696 (57 %) by motion artefact, while for 224 (18 %) there were no concomitant factors identified. Respiratory pauses of longer duration (>15 s) preceding hypoxic events, were associated with a relatively slow decline in SpO 2 and more prolonged hypoxia compared to shorter pauses. Hypoxic events are frequently accompanied by respiratory pauses and/or motion artefact. Real-time monitoring and input of respiratory waveform may thus improve the function of automated oxygen controllers, allowing pre-emptive responses to respiratory pauses. Furthermore, use of motion-resistant oximeters and plethysmographic waveform assessment procedures will help to optimise feedback control of inspired oxygen delivery.

Knockdown of miR-210 decreases hypoxic glioma stem cells stemness and radioresistance.

PubMed

Yang, Wei; Wei, Jing; Guo, Tiantian; Shen, Yueming; Liu, Fenju

2014-08-01

Glioma contains abundant hypoxic regions which provide niches to promote the maintenance and expansion of glioma stem cells (GSCs), which are resistant to conventional therapies and responsible for recurrence. Given the fact that miR-210 plays a vital role in cellular adaption to hypoxia and in stem cell survival and stemness maintenance, strategies correcting the aberrantly expressed miR-210 might open up a new therapeutic avenue to hypoxia GSCs. In the present study, to explore the possibility of miR-210 as an effective therapeutic target to hypoxic GSCs, we employed a lentiviral-mediated anti-sense miR-210 gene transfer technique to knockdown miR-210 expression and analyze phenotypic changes in hypoxic U87s and SHG44s cells. We found that hypoxia led to an increased HIF-2α mRNA expression and miR-210 expression in GSCs. Knockdown of miR-210 decreased neurosphere formation capacity, stem cell marker expression and cell viability, and induced differentiation and G0/G1 arrest in hypoxic GSCs by partially rescued Myc antagonist (MNT) protein expression. Knockdown of MNT could reverse the gene expression changes and the growth inhibition resulting from knockdown of miR-210 in hypoxic GSCs. Moreover, knockdown of miR-210 led to increased apoptotic rate and Caspase-3/7 activity and decreased invasive capacity, reactive oxygen species (ROS) and lactate production and radioresistance in hypoxic GSCs. These findings suggest that miR-210 might be a potential therapeutic target to eliminate GSCs located in hypoxic niches. Copyright © 2014 Elsevier Inc. All rights reserved.

Long-Term Overexpression of Hsp70 Does Not Protect against Cardiac Dysfunction and Adverse Remodeling in a MURC Transgenic Mouse Model with Chronic Heart Failure and Atrial Fibrillation

PubMed Central

Bernardo, Bianca C.; Sapra, Geeta; Patterson, Natalie L.; Cemerlang, Nelly; Kiriazis, Helen; Ueyama, Tomomi; Febbraio, Mark A.; McMullen, Julie R.

2015-01-01

Previous animal studies had shown that increasing heat shock protein 70 (Hsp70) using a transgenic, gene therapy or pharmacological approach provided cardiac protection in models of acute cardiac stress. Furthermore, clinical studies had reported associations between Hsp70 levels and protection against atrial fibrillation (AF). AF is the most common cardiac arrhythmia presenting in cardiology clinics and is associated with increased rates of heart failure and stroke. Improved therapies for AF and heart failure are urgently required. Despite promising observations in animal studies which targeted Hsp70, we recently reported that increasing Hsp70 was unable to attenuate cardiac dysfunction and pathology in a mouse model which develops heart failure and intermittent AF. Given our somewhat unexpected finding and the extensive literature suggesting Hsp70 provides cardiac protection, it was considered important to assess whether Hsp70 could provide protection in another mouse model of heart failure and AF. The aim of the current study was to determine whether increasing Hsp70 could attenuate adverse cardiac remodeling, cardiac dysfunction and episodes of arrhythmia in a mouse model of heart failure and AF due to overexpression of Muscle-Restricted Coiled-Coil (MURC). Cardiac function and pathology were assessed in mice at approximately 12 months of age. We report here, that chronic overexpression of Hsp70 was unable to provide protection against cardiac dysfunction, conduction abnormalities, fibrosis or characteristic molecular markers of the failing heart. In summary, elevated Hsp70 may provide protection in acute cardiac stress settings, but appears insufficient to protect the heart under chronic cardiac disease conditions. PMID:26660322

Long-Term Overexpression of Hsp70 Does Not Protect against Cardiac Dysfunction and Adverse Remodeling in a MURC Transgenic Mouse Model with Chronic Heart Failure and Atrial Fibrillation.

PubMed

Bernardo, Bianca C; Sapra, Geeta; Patterson, Natalie L; Cemerlang, Nelly; Kiriazis, Helen; Ueyama, Tomomi; Febbraio, Mark A; McMullen, Julie R

2015-01-01

Previous animal studies had shown that increasing heat shock protein 70 (Hsp70) using a transgenic, gene therapy or pharmacological approach provided cardiac protection in models of acute cardiac stress. Furthermore, clinical studies had reported associations between Hsp70 levels and protection against atrial fibrillation (AF). AF is the most common cardiac arrhythmia presenting in cardiology clinics and is associated with increased rates of heart failure and stroke. Improved therapies for AF and heart failure are urgently required. Despite promising observations in animal studies which targeted Hsp70, we recently reported that increasing Hsp70 was unable to attenuate cardiac dysfunction and pathology in a mouse model which develops heart failure and intermittent AF. Given our somewhat unexpected finding and the extensive literature suggesting Hsp70 provides cardiac protection, it was considered important to assess whether Hsp70 could provide protection in another mouse model of heart failure and AF. The aim of the current study was to determine whether increasing Hsp70 could attenuate adverse cardiac remodeling, cardiac dysfunction and episodes of arrhythmia in a mouse model of heart failure and AF due to overexpression of Muscle-Restricted Coiled-Coil (MURC). Cardiac function and pathology were assessed in mice at approximately 12 months of age. We report here, that chronic overexpression of Hsp70 was unable to provide protection against cardiac dysfunction, conduction abnormalities, fibrosis or characteristic molecular markers of the failing heart. In summary, elevated Hsp70 may provide protection in acute cardiac stress settings, but appears insufficient to protect the heart under chronic cardiac disease conditions.

Transglutaminase 2 overexpression induces depressive-like behavior and impaired TrkB signaling in mice

PubMed Central

Pandya, Chirayu D; Hoda, Nasrul; Crider, Amanda; Peter, Diya; Kutiyanawalla, Ammar; Kumar, Sanjiv; Ahmed, Anthony O; Turecki, Gustavo; Hernandez, Caterina M; Terry, Alvin V

2016-01-01

Serotonin (5-HT) and brain derived neurotrophic factor (BDNF) are two signaling molecules that play important regulatory roles in the development and plasticity of neural circuits that are known to be altered in depression. However, the mechanism by which 5-HT regulates BDNF signaling is unknown. In the present study, we found that 5-HT treatment increases BDNF receptor, TrkB (tropomyosin related kinase B) levels in mouse primary cortical neurons via a Rac1 (RAS-related C3 botulinum toxin substrate 1)-dependent mechanism. Significant increases in the levels of transglutaminase 2 (TG2, which is implicated in transamidation of 5-HT to Rac1) are observed in the mouse prefrontal cortex (PFC) following chronic exposure to stress. We also found that TG2 levels are increased in the postmortem PFC of depressed suicide subjects relative to matched controls. Moreover, in mice, neuronal overexpression of TG2 resulted in the atrophy of neurons and reduced levels of TrkB in the PFC as well as a depressive-like phenotype. Overexpression of TG2 in mouse cortical neurons reduced TrkB levels as a result of impaired endocytosis of TrkB. TG2 inhibition by either a viral particle or pharmacological approach attenuated behavioral deficits caused by chronic unpredictable stress. Moreover, the overexpression of TrkB in the mouse PFC ameliorated the depressive-like phenotype of TG2 overexpressed mice. Taken together, these postmortem and preclinical findings identify TG2 as a critical mediator of the altered TrkB expression and depressive-like behaviors associated with chronic exposure to stress and suggest that TG2 may represent a novel therapeutic target in depression. PMID:27620841

Severe Acute Subdural Hemorrhage in a Patient With Glutaric Aciduria Type I After Minor Head Trauma: A Case Report.

PubMed

Zielonka, Matthias; Braun, Katrin; Bengel, Andreas; Seitz, Angelika; Kölker, Stefan; Boy, Nikolas

2015-07-01

Glutaric aciduria type I is a rare metabolic disorder caused by deficiency of glutaryl-coenzyme A dehydrogenase. Chronic subdural hematomas have been reported in glutaric aciduria type I and are considered as important differential diagnosis of nonaccidental head trauma. However, chronic subdural hematomas are usually thought to remain clinically silent in these patients. Here we report on a hitherto asymptomatic glutaric aciduria type I patient who developed severe, acute subdural hemorrhage after minor accidental head injury at age 23 months. Computed tomography confirmed significant mass effect on the brain necessitating decompressive hemicraniectomy. Subdural hemorrhage caused large hypoxic lesions of the cerebral cortex and subcortical regions resulting in spastic tetraplegia, dystonia, and loss of developmental milestones. This report emphasizes that acute subdural hemorrhage may be a life-threatening complication in glutaric aciduria type I patients after minor head trauma and should be considered in those patients presenting with neurologic deterioration after accidental head injury. © The Author(s) 2014.

The Genetic Basis of Chronic Mountain Sickness

PubMed Central

Ronen, Roy; Zhou, Dan; Bafna, Vineet; Haddad, Gabriel G.

2014-01-01

Chronic mountain sickness (CMS) is a disease that affects many high-altitude dwellers, particularly in the Andean Mountains in South America. The hallmark symptom of CMS is polycythemia, which causes increased risk of pulmonary hypertension and stroke (among other symptoms). A prevailing hypothesis in high-altitude medicine is that CMS results from a population-specific “maladaptation” to the hypoxic conditions at high altitude. In contrast, the prevalence of CMS is very low in other high-altitude populations (e.g., Tibetans and Ethiopians), which are seemingly well adapted to hypoxia. In recent years, concurrent with the advent of genomic technologies, several studies have investigated the genetic basis of adaptation to altitude. These studies have identified several candidate genes that may underlie the adaptation, or maladaptation. Interestingly, some of these genes are targeted by known drugs, raising the possibility of new treatments for CMS and other ischemic diseases. We review recent discoveries, alongside the methodologies used to obtain them, and outline some of the challenges remaining in the field. PMID:25362634

An audit of the patient's experience of arterial blood gas testing.

PubMed

Crawford, Anne

Arterial puncture is the most common method used to obtain a sample for the measurement of arterial blood gases (ABGs) and is essential to guide the prescription of long-term oxygen therapy (LTOT) in patients with chronic hypoxic lung disease. However, this procedure is often reported by patients as a painful and unpleasant experience, which to date has not been explored. This audit specifically examines the subjective views of a small group of patients (n = 41) who are receiving LTOT who have experienced repeated ABGs. Results demonstrated that 49% (n = 20) were poorly informed regarding what the procedure involved, almost half the patients 49% (n = 20) recalled pain levels of 5 and above on a visual analogue scale and 66% (n = 27) were totally unaware that the test could make a considerable difference to their treatment. While highlighting the deficits in current practice locally, this audit concludes that the respiratory nurse specialist is in an ideal position to implement changes to improve the patient's experience of chronic disease management.

Physiological effects of intermittent hypoxia.

PubMed

Powell, F L; Garcia, N

2000-01-01

Intermittent hypoxia (IH), or periodic exposure to hypoxia interrupted by return to normoxia or less hypoxic conditions, occurs in many circumstances. In high altitude mountaineering, IH is used to optimize acclimatization although laboratory studies have not generally revealed physiologically significant benefits. IH enhances athletic performance at sea level if blood oxygen capacity increases and the usual level of training is not decreased significantly. IH for high altitude workers who commute from low altitude homes is of considerable practical interest and the ideal commuting schedule for physical and mental performance is being studied. The effect of oxygen enrichment at altitude (i.e., intermittent normoxia on a background of chronic hypoxia) on human performance is under study also. Physiological mechanisms of IH, and specifically the differences between effects of IH and acute or chronic continuous hypoxia remains to be determined. Biomedical researchers are defining the molecular and cellular mechanisms for effects of hypoxia on the body in health and disease. A comparative approach may provide additional insight about the biological significance of these effects.

Hepatocyte growth factor: a regulator of extracellular matrix genes in mouse mesangial cells.

PubMed

Laping, N J; Olson, B A; Ho, T; Ziyadeh, F N; Albrightson, C R

2000-04-01

The potential role of hepatocyte growth factor (HGF) in regulating extracellular matrix in mouse mesangial cells (MMC) was evaluated. Functional HGF receptors were deed in MMC by HGF-induced extracellular acidification, a response that was inhibited by the HGF inhibitor HGF/NK2, a splice variant expressing the N-terminal domain through the second kringle domain HGF also increased fibronectin and collagen alpha1 (IV) mRNA levels in these cells; the increases were associated with a concentration-dependent increase in transcriptional activity of the collagen alpha1 (IV) gene. HGF also stimulated fibronectin and collagen alpha1 (IV) mRNA levels in primary rabbit proximal tubule epithelial cells To evaluate the potential consequences of chronic elevation of HGF on renal fuction, HGF was administered continuously for 18 days to normal and diabetic C57BLKS/J lepr(db) mice. In the diabetic mice, HGF reduced creatinine clearance and increased microalbuminuria, indicating that chronic exposure to HGF impairs renal function. Thus, chronically elevated HGF may contribute to the progression of chronic renal disease in diabetes by decreasing the glomerular filtration rate and possibly promoting the accumulation of extracellular matrix.

Biofilm Formation Protects Salmonella from the Antibiotic Ciprofloxacin In Vitro and In Vivo in the Mouse Model of chronic Carriage.

PubMed

González, Juan F; Alberts, Halley; Lee, Joel; Doolittle, Lauren; Gunn, John S

2018-01-09

Typhoid fever is caused by the human-restricted pathogen Salmonella enterica sv. Typhi. Approximately 5% of people that resolve the disease become chronic carriers, with the gallbladder as the main reservoir of the bacteria. Of these, about 90% present with gallstones, on which Salmonella form biofilms. Because S. Typhi is a human-restricted pathogen, these carriers are the main source of dissemination of the disease; unfortunately, antibiotic treatment has shown to be an ineffective therapy. This is believed to be caused by the inherent antibiotic resistance conferred by Salmonella biofilms growing on gallstones. The gallstone mouse model with S. Typhimurium has proven to be an excellent surrogate for S. Typhi chronic infection. In this study, we test the hypothesis that the biofilm state confers Salmonella with the increased resistance to antibiotics observed in cases of chronic carriage. We found that, in the biofilm state, Salmonella is significantly more resistant to ciprofloxacin, a common antibiotic used for the treatment of Salmonella, both in vitro (p < 0.001 for both S. Typhi and S. Typhimurium with respect to planktonic cells) and in vivo (p = 0.0035 with respect to control mice).

Chronic 5-HT4 receptor agonist treatment restores learning and memory deficits in a neuroendocrine mouse model of anxiety/depression.

PubMed

Darcet, Flavie; Gardier, Alain M; David, Denis J; Guilloux, Jean-Philippe

2016-03-11

Cognitive disturbances are often reported as serious invalidating symptoms in patients suffering from major depression disorders (MDD) and are not fully corrected by classical monoaminergic antidepressant drugs. If the role of 5-HT4 receptor agonists as cognitive enhancers is well established in naïve animals or in animal models of cognitive impairment, their cognitive effects in the context of stress need to be examined. Using a mouse model of anxiety/depression (CORT model), we reported that a chronic 5-HT4 agonist treatment (RS67333, 1.5mg/kg/day) restored chronic corticosterone-induced cognitive deficits, including episodic-like, associative and spatial learning and memory impairments. On the contrary, a chronic monoaminergic antidepressant drug treatment with fluoxetine (18mg/kg/day) only partially restored spatial learning and memory deficits and had no effect in the associative/contextual task. These results suggest differential mechanisms underlying cognitive effects of these drugs. Finally, the present study highlights 5-HT4 receptor stimulation as a promising therapeutic mechanism to alleviate cognitive symptoms related to MDD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Xeroderma Pigmentosum Group C Deficiency Alters Cigarette Smoke DNA Damage Cell Fate and Accelerates Emphysema Development.

PubMed

Sears, Catherine R; Zhou, Huaxin; Justice, Matthew J; Fisher, Amanda J; Saliba, Jacob; Lamb, Isaac; Wicker, Jessica; Schweitzer, Kelly S; Petrache, Irina

2018-03-01

Cigarette smoke (CS) exposure is a major risk factor for the development of emphysema, a common disease characterized by loss of cells comprising the lung parenchyma. The mechanisms of cell injury leading to emphysema are not completely understood but are thought to involve persistent cytotoxic or mutagenic DNA damage induced by CS. Using complementary cell culture and mouse models of CS exposure, we investigated the role of the DNA repair protein, xeroderma pigmentosum group C (XPC), on CS-induced DNA damage repair and emphysema. Expression of XPC was decreased in mouse lungs after chronic CS exposure and XPC knockdown in cultured human lung epithelial cells decreased their survival after CS exposure due to activation of the intrinsic apoptosis pathway. Similarly, cell autophagy and apoptosis were increased in XPC-deficient mouse lungs and were further increased by CS exposure. XPC deficiency was associated with structural and functional changes characteristic of emphysema, which were worsened by age, similar to levels observed with chronic CS exposure. Taken together, these findings suggest that repair of DNA damage by XPC plays an important and previously unrecognized role in the maintenance of alveolar structures. These findings support that loss of XPC, possibly due to chronic CS exposure, promotes emphysema development and further supports a link between DNA damage, impaired DNA repair, and development of emphysema.

[Follow-up of newborns with hypoxic-ischaemic encephalopathy].

PubMed

Martínez-Biarge, M; Blanco, D; García-Alix, A; Salas, S

2014-07-01

Hypothermia treatment for newborn infants with hypoxic-ischemic encephalopathy reduces the number of neonates who die or have permanent neurological deficits. Although this therapy is now standard of care, neonatal hypoxic-ischaemic encephalopathy still has a significant impact on the child's neurodevelopment and quality of life. Infants with hypoxic-ischaemic encephalopathy should be enrolled in multidisciplinary follow-up programs in order to detect impairments, to initiate early intervention, and to provide counselling and support for families. This article describes the main neurodevelopmental outcomes after term neonatal hypoxic-ischaemic encephalopathy. We offer recommendations for follow-up based on the infant's clinical condition and other prognostic indicators, mainly neonatal neuroimaging. Other aspects, such as palliative care and medico-legal issues, are also briefly discussed. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Hypoxyprobe™ reveals dynamic spatial and temporal changes in hypoxia in a mouse model of endometrial breakdown and repair.

PubMed

Cousins, Fiona L; Murray, Alison A; Scanlon, Jessica P; Saunders, Philippa T K

2016-01-19

Menstruation is the culmination of a cascade of events, triggered by the withdrawal of progesterone at the end of the menstrual cycle. Initiation of tissue destruction and endometrial shedding causes spiral arteriole constriction in the functional layer of the endometrium. Upregulation of genes involved in angiogenesis and immune cell recruitment, two processes that are essential to successful repair and remodelling of the endometrium, both thought to be induced by reduced oxygen has been reported. Evidence for stabilisation/increased expression of the transcriptional regulator hypoxia inducible factor in the human endometrium at menses has been published. The current literature debates whether hypoxia plays an essential role during menstrual repair, therefore this study aims to delineate a role for hypoxia using a sensitive detection method (the Hypoxyprobe™) in combination with an established mouse model of endometrial breakdown and repair. Using our mouse model of menses, during which documented breakdown and synchronous repair occurs in a 24 h timeframe, in combination with the Hypoxyprobe™ detection system, oxygen tensions within the uterus were measured. Immunostaining revealed striking spatial and temporal fluctuations in hypoxia during breakdown and showed that the epithelium is also exposed to hypoxic conditions during the repair phase. Furthermore, time-dependent changes in tissue hypoxia correlated with the regulation of mRNAs encoding for the angiogenic genes vascular endothelial growth factor and stromal derived factor (Cxcl12). Our findings are consistent with a role for focal hypoxia during endometrial breakdown in regulating gene expression during menses. These data have implications for treatment of endometrial pathologies such as heavy menstrual bleeding.

FKBPL Is a Critical Antiangiogenic Regulator of Developmental and Pathological Angiogenesis

PubMed Central

Yakkundi, Anita; Bennett, Rachel; Hernández-Negrete, Ivette; Delalande, Jean-Marie; Hanna, Mary; Lyubomska, Oksana; Arthur, Kenneth; Short, Amy; McKeen, Hayley; Nelson, Laura; McCrudden, Cian M.; McNally, Ross; McClements, Lana; McCarthy, Helen O.; Burns, Alan J.; Bicknell, Roy; Kissenpfennig, Adrien

2015-01-01

Objective— The antitumor effects of FK506-binding protein like (FKBPL) and its extracellular role in angiogenesis are well characterized; however, its role in physiological/developmental angiogenesis and the effect of FKBPL ablation has not been evaluated. This is important as effects of some angiogenic proteins are dosage dependent. Here we evaluate the regulation of FKBPL secretion under angiogenic stimuli, as well as the effect of FKBPL ablation in angiogenesis using mouse and zebrafish models. Approach and Results— FKBPL is secreted maximally by human microvascular endothelial cells and fibroblasts, and this was specifically downregulated by proangiogenic hypoxic signals, but not by the angiogenic cytokines, VEGF or IL8. FKBPL’s critical role in angiogenesis was supported by our inability to generate an Fkbpl knockout mouse, with embryonic lethality occurring before E8.5. However, whilst Fkbpl heterozygotic embryos showed some vasculature irregularities, the mice developed normally. In murine angiogenesis models, including the ex vivo aortic ring assay, in vivo sponge assay, and tumor growth assay, Fkbpl+/− mice exhibited increased sprouting, enhanced vessel recruitment, and faster tumor growth, respectively, supporting the antiangiogenic function of FKBPL. In zebrafish, knockdown of zFkbpl using morpholinos disrupted the vasculature, and the phenotype was rescued with hFKBPL. Interestingly, this vessel disruption was ineffective when zcd44 was knocked-down, supporting the dependency of zFkbpl on zCd44 in zebrafish. Conclusions— FKBPL is an important regulator of angiogenesis, having an essential role in murine and zebrafish blood vessel development. Mouse models of angiogenesis demonstrated a proangiogenic phenotype in Fkbpl heterozygotes. PMID:25767277

Intestine-specific Disruption of Hypoxia-inducible Factor (HIF)-2α Improves Anemia in Sickle Cell Disease.

PubMed

Das, Nupur; Xie, Liwei; Ramakrishnan, Sadeesh K; Campbell, Andrew; Rivella, Stefano; Shah, Yatrik M

2015-09-25

Sickle cell disease (SCD) is caused by genetic defects in the β-globin chain. SCD is a frequently inherited blood disorder, and sickle cell anemia is a common type of hemoglobinopathy. During anemia, the hypoxic response via the transcription factor hypoxia-inducible factor (HIF)-2α is highly activated in the intestine and is essential in iron absorption. Intestinal disruption of HIF-2α protects against tissue iron accumulation in iron overload anemias. However, the role of intestinal HIF-2α in regulating anemia in SCD is currently not known. Here we show that in mouse models of SCD, disruption of intestinal HIF-2α significantly decreased tissue iron accumulation. This was attributed to a decrease in intestinal iron absorptive genes, which were highly induced in a mouse model of SCD. Interestingly, disruption of intestinal HIF-2α led to a robust improvement in anemia with an increase in RBC, hemoglobin, and hematocrit. This was attributed to improvement in RBC survival, hemolysis, and insufficient erythropoiesis, which is evident from a significant decrease in serum bilirubin, reticulocyte counts, and serum erythropoietin following intestinal HIF-2α disruption. These data suggest that targeting intestinal HIF-2α has a significant therapeutic potential in SCD pathophysiology. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Carbamoyl phosphate synthetase-1 is a rapid turnover biomarker in mouse and human acute liver injury.

PubMed

Weerasinghe, Sujith V W; Jang, You-Jin; Fontana, Robert J; Omary, M Bishr

2014-08-01

Several serum markers are used to assess hepatocyte damage, but they have limitations related to etiology specificity and prognostication. Identification of novel hepatocyte-specific biomarkers could provide important prognostic information and better pathogenesis classification. We tested the hypothesis that hepatocyte-selective biomarkers are released after subjecting isolated mouse hepatocytes to Fas-ligand-mediated apoptosis. Proteomic analysis of hepatocyte culture medium identified the mitochondrial matrix protein carbamoyl phosphate synthetase-1 (CPS1) among the most readily detected proteins that are released by apoptotic hepatocytes. CPS1 was also detected in mouse serum upon acute challenge with Fas-ligand or acetaminophen and in hepatocytes upon hypoosmotic stress, independent of hepatocyte caspase activation. Furthermore, CPS1 was observed in sera of mice chronically fed the hepatotoxin 3,5-diethoxycarbonyl-1,4-dihydrocollidine. Mouse CPS1 detectability was similar in serum and plasma, and its half-life was 126 ± 9 min. Immune staining showed that CPS1 localized to mouse hepatocytes but not ductal cells. Analysis of a few serum samples from patients with acute liver failure (ALF) due to acetaminophen, Wilson disease, or ischemia showed readily detectable CPS1 that was not observed in several patients with chronic viral hepatitis or in control donors. Notably, CPS1 rapidly decreased to undetectable levels in sera of patients with acetaminophen-related ALF who ultimately recovered, while alanine aminotransferase levels remained elevated. Therefore, CPS1 becomes readily detectable upon hepatocyte apoptotic and necrotic death in culture or in vivo. Its abundance and short serum half-life, compared with alanine aminotransferase, suggest that it may be a useful prognostic biomarker in human and mouse liver injury. Copyright © 2014 the American Physiological Society.

Archaeal enrichment in the hypoxic zone in the northern Gulf of Mexico.

PubMed

Gillies, Lauren E; Thrash, J Cameron; deRada, Sergio; Rabalais, Nancy N; Mason, Olivia U

2015-10-01

Areas of low oxygen have spread exponentially over the past 40 years, and are cited as a key stressor on coastal ecosystems. The world's second largest coastal hypoxic (≤ 2 mg of O2 l(-1)) zone occurs annually in the northern Gulf of Mexico. The net effect of hypoxia is the diversion of energy flow away from higher trophic levels to microorganisms. This energy shunt is consequential to the overall productivity of hypoxic water masses and the ecosystem as a whole. In this study, water column samples were collected at 39 sites in the nGOM, 21 of which were hypoxic. Analysis of the microbial community along a hypoxic to oxic dissolved oxygen gradient revealed that the relative abundance (iTag) of Thaumarchaeota species 16S rRNA genes (> 40% of the microbial community in some hypoxic samples), the absolute abundance (quantitative polymerase chain reaction; qPCR) of Thaumarchaeota 16S rRNA genes and archaeal ammonia-monooxygenase gene copy number (qPCR) were significantly higher in hypoxic samples. Spatial interpolation of the microbial and chemical data revealed a continuous, shelfwide band of low dissolved oxygen waters that were dominated by Thaumarchaeota (and Euryarchaeota), amoA genes and high concentrations of phosphate in the nGOM, thus implicating physicochemical forcing on microbial abundance. © 2015 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Hypoxic preconditioning protects photoreceptors against light damage independently of hypoxia inducible transcription factors in rods.

PubMed

Kast, Brigitte; Schori, Christian; Grimm, Christian

2016-05-01

Hypoxic preconditioning protects photoreceptors against light-induced degeneration preserving retinal morphology and function. Although hypoxia inducible transcription factors 1 and 2 (HIF1, HIF2) are the main regulators of the hypoxic response, photoreceptor protection does not depend on HIF1 in rods. Here we used rod-specific Hif2a single and Hif1a;Hif2a double knockout mice to investigate the potential involvement of HIF2 in rods for protection after hypoxic preconditioning. To identify potential HIF2 target genes in rods we determined the retinal transcriptome of hypoxic control and rod-specific Hif2a knockouts by RNA sequencing. We show that rods do not need HIF2 for hypoxia-induced increased survival after light exposure. The transcriptomic analysis revealed a number of genes that are potentially regulated by HIF2 in rods; among those were Htra1, Timp3 and Hmox1, candidates that are interesting due to their connection to human degenerative diseases of the retina. We conclude that neither HIF1 nor HIF2 are required in photoreceptors for protection by hypoxic preconditioning. We hypothesize that HIF transcription factors may be needed in other cells to produce protective factors acting in a paracrine fashion on photoreceptor cells. Alternatively, hypoxic preconditioning induces a rod-intrinsic response that is independent of HIF transcription factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimized Mouse Models for Liver Fibrosis.

PubMed

Kim, Yong Ook; Popov, Yury; Schuppan, Detlef

2017-01-01

Fibrosis is the excessive accumulation of extracellular matrix components due to chronic injury, with collagens as predominant structural components. Liver fibrosis can progress to cirrhosis, which is characterized by a severe distortion of the delicate hepatic vascular architecture, the shunting of the blood supply away from hepatocytes and the resultant functional liver failure. Cirrhosis is associated with a highly increased morbidity and mortality and represents the major hard endpoint in clinical studies of chronic liver diseases. Moreover, cirrhosis is a strong cofactor of primary liver cancer. In vivo models are indispensable tools to study the cellular and molecular mechanisms of liver fibrosis and to develop specific antifibrotic therapies towards clinical translation. Here, we provide a detailed description of select optimized mouse models of liver fibrosis and state-of-the-art fibrosis readouts.

Recent mouse models and vaccine candidates for preventing chronic/latent tuberculosis infection and its reactivation.

PubMed

Pedroza-Roldán, César; Flores-Valdez, Mario Alberto

2017-08-31

Tuberculosis (TB) remains a major challenge in public health worldwide. Until today, the only widely used and approved vaccine is the Mycobacterium bovis bacille Calmette-Guerin (BCG). This vaccine provides a highly variable level of protection against the active, pulmonary form of tuberculosis, and practically none against the latent form of TB infection. This disparity in protection has been extensively studied, and for this reason, several groups have focused their research on the quest for attenuated vaccines based on M. tuberculosis or on the identification of latency-associated antigens that can be incorporated into modified BCG, or that can be used as adjuvanted subunit vaccines. In order to seek new potential antigens relevant for infection, some researchers have performed experiments with highly sensitive techniques such as transcriptomic and proteomic analyses using sputum samples from humans or by using mouse models resembling several aspects of TB. In this review, we focus on reports of new mouse models or mycobacterial antigens recently tested for developing vaccine candidates against chronic/latent tuberculosis and its reactivation.

A non-invasive approach to monitor chronic lymphocytic leukemia engraftment in a xenograft mouse model using ultra-small superparamagnetic iron oxide-magnetic resonance imaging (USPIO-MRI).

PubMed

Valdora, Francesca; Cutrona, Giovanna; Matis, Serena; Morabito, Fortunato; Massucco, Carlotta; Emionite, Laura; Boccardo, Simona; Basso, Luca; Recchia, Anna Grazia; Salvi, Sandra; Rosa, Francesca; Gentile, Massimo; Ravina, Marco; Pace, Daniele; Castronovo, Angela; Cilli, Michele; Truini, Mauro; Calabrese, Massimo; Neri, Antonino; Neumaier, Carlo Emanuele; Fais, Franco; Baio, Gabriella; Ferrarini, Manlio

2016-11-01

Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia among adults. Despite its indolent nature, CLL remains an incurable disease. Herein we aimed to monitor CLL disease engraftment and, progression/regression in a xenograft CLL mouse model using ultra-small superparamagnetic iron oxide-magnetic resonance imaging (USPIO-MRI). Spleen contrast enhancement, quantified as percentage change in signal intensity upon USPIO administration, demonstrated a difference due to a reduced USPIO uptake, in the spleens of mice injected with CLL cells (NSG-CLL, n=71) compared to controls (NSG-CTR, n=17). These differences were statistically significant both after 2 and 4weeks from CLL cells injection. In addition comparison of mice treated with rituximab with untreated controls for changes in spleen iron uptake confirmed that it is possible to monitor treatment efficacy in this mouse model of CLL using USPIO-enhanced MRI. Further applications could include the preclinical in vivo monitoring of new therapies and the clinical evaluation of CLL patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Chronic Fluoxetine Induces the Enlargement of Perforant Path-Granule Cell Synapses in the Mouse Dentate Gyrus

PubMed Central

Kitahara, Yosuke; Ohta, Keisuke; Hasuo, Hiroshi; Shuto, Takahide; Kuroiwa, Mahomi; Sotogaku, Naoki; Togo, Akinobu; Nakamura, Kei-ichiro; Nishi, Akinori

2016-01-01

A selective serotonin reuptake inhibitor is the most commonly prescribed antidepressant for the treatment of major depression. However, the mechanisms underlying the actions of selective serotonin reuptake inhibitors are not fully understood. In the dentate gyrus, chronic fluoxetine treatment induces increased excitability of mature granule cells (GCs) as well as neurogenesis. The major input to the dentate gyrus is the perforant path axons (boutons) from the entorhinal cortex (layer II). Through voltage-sensitive dye imaging, we found that the excitatory neurotransmission of the perforant path synapse onto the GCs in the middle molecular layer of the mouse dentate gyrus (perforant path-GC synapse) is enhanced after chronic fluoxetine treatment (15 mg/kg/day, 14 days). Therefore, we further examined whether chronic fluoxetine treatment affects the morphology of the perforant path-GC synapse, using FIB/SEM (focused ion beam/scanning electron microscopy). A three-dimensional reconstruction of dendritic spines revealed the appearance of extremely large-sized spines after chronic fluoxetine treatment. The large-sized spines had a postsynaptic density with a large volume. However, chronic fluoxetine treatment did not affect spine density. The presynaptic boutons that were in contact with the large-sized spines were large in volume, and the volumes of the mitochondria and synaptic vesicles inside the boutons were correlated with the size of the boutons. Thus, the large-sized perforant path-GC synapse induced by chronic fluoxetine treatment contains synaptic components that correlate with the synapse size and that may be involved in enhanced glutamatergic neurotransmission. PMID:26788851

Least-cost control of agricultural nutrient contributions to the Gulf of Mexico hypoxic zone

USDA-ARS?s Scientific Manuscript database

In 2007, the hypoxic zone in the Gulf of Mexico, measuring 20,720 km**2, was one of the two largest reported since measurement of the zone began in 1985. The extent of the hypoxic zone is related to nitrogen and phosphorous loadings originating on agricultural fields in the upper Midwest. This stud...

[Effect of mexamine on the resistance of dogs to acute hypoxic hypoxia].

PubMed

Vasin, M V; Antipov, V V; Davydov, B I; Suvorov, N N

1975-01-01

As demonstrated in experiments staged on dogs mexamine hydrochloride, used in a dose of 20 mg/kg by the intraperiotoneal route 1.5 hours before the onset of acute hypoxic hypoxia increases the resistance of the organism to oxigen deficiency. Mexamine is capable of significantly intensity hypothermy in dogs during acute hypoxic hypoxia.

Pain vulnerability and DNA methyltransferase 3a involved in the affective dimension of chronic pain

PubMed Central

Wang, Wei; Li, Caiyue; Cai, Youqing; Pan, Zhizhong Z

2017-01-01

Chronic pain with comorbid emotional disorders is a prevalent neurological disease in patients under various pathological conditions, yet patients show considerable difference in their vulnerability to developing chronic pain. Understanding the neurobiological basis underlying this pain vulnerability is essential to develop targeted therapies of higher efficiency in pain treatment of precision medicine. However, this pain vulnerability has not been addressed in preclinical pain research in animals to date. In this study, we investigated individual variance in both sensory and affective/emotional dimensions of pain behaviors in response to chronic neuropathic pain condition in a mouse model of chronic pain. We found that mice displayed considerably diverse sensitivities in the chronic pain-induced anxiety- and depression-like behaviors of affective pain. Importantly, the mouse group that was more vulnerable to developing anxiety was also more vulnerable to developing depressive behavior under the chronic pain condition. In contrast, there was relatively much less variance in individual responses in the sensory dimension of pain sensitization. Molecular analysis revealed that those mice vulnerable to developing the emotional disorders showed a significant reduction in the protein level of DNA methyltransferase 3a in the emotion-processing central nucleus of the amygdala. In addition, social stress also revealed significant individual variance in anxiety behavior in mice. These findings suggest that individual pain vulnerability may be inherent mostly in the emotional/affective component of chronic pain and remain consistent in different aspects of negative emotion, in which adaptive changes in the function of DNA methyltransferase 3a for DNA methylation in central amygdala may play an important role. This may open a new avenue of basic research into the neurobiological mechanisms underlying pain vulnerability. PMID:28849714

Persistent effects of chronic clozapine on the cellular and behavioral responses to LSD in mice

PubMed Central

Moreno, José L.; Holloway, Terrell; Umali, Adrienne; Rayannavar, Vinayak; Sealfon, Stuart C.

2013-01-01

Rationale In schizophrenia patients, optimal treatment with antipsychotics requires weeks to months of sustained drug therapy. However, single administration of antipsychotic drugs can reverse schizophrenia-like behavioral alterations in rodent models of psychosis. This raises questions about the physiological relevance of such antipsychotic-like activity. Objective This study evaluates the effects of chronic treatment with clozapine on the cellular and behavioral responses induced by the hallucinogenic serotonin 5-HT2A receptor agonist lysergic acid diethylamide (LSD) as a mouse model of psychosis. Method Mice were treated chronically (21 days) with 25 mg/kg/day clozapine. Experiments were conducted 1, 7, 14, and 21 days after the last clozapine administration. [3H]Ketanserin binding and 5-HT2A mRNA expression were determined in mouse somatosensory cortex. Head-twitch behavior, expression of c-fos, which is induced by all 5-HT2A agonists, and expression of egr-1 and egr-2, which are LSD-like specific, were assayed. Results Head-twitch response was decreased and [3H]ketanserin binding was downregulated in 1, 7, and 14 days after chronic clozapine. 5-HT2A mRNA was reduced 1 day after chronic clozapine. Induction of c-fos, but not egr-1 and egr-2, was rescued 7 days after chronic clozapine. These effects were not observed after short treatment (2 days) with clozapine or chronic haloperidol (1 mg/kg/day). Conclusion Our findings provide a murine model of chronic atypical antipsychotic drug action and suggest downregulation of the 5-HT2A receptor as a potential mechanism involved in these persistent therapeutic-like effects. PMID:22842765

Underlying chronic inflammation alters the profile and mechanisms of acute neutrophil recruitment.

PubMed

Ma, Bin; Whiteford, James R; Nourshargh, Sussan; Woodfin, Abigail

2016-11-01

Chronically inflamed tissues show altered characteristics that include persistent populations of inflammatory leukocytes and remodelling of the vascular network. As the majority of studies on leukocyte recruitment have been carried out in normal healthy tissues, the impact of underlying chronic inflammation on ongoing leukocyte recruitment is largely unknown. Here, we investigate the profile and mechanisms of acute inflammatory responses in chronically inflamed and angiogenic tissues, and consider the implications for chronic inflammatory disorders. We have developed a novel model of chronic ischaemia of the mouse cremaster muscle that is characterized by a persistent population of monocyte-derived cells (MDCs), and capillary angiogenesis. These tissues also show elevated acute neutrophil recruitment in response to locally administered inflammatory stimuli. We determined that Gr1 low MDCs, which are widely considered to have anti-inflammatory and reparative functions, amplified acute inflammatory reactions via the generation of additional proinflammatory signals, changing both the profile and magnitude of the tissue response. Similar vascular and inflammatory responses, including activation of MDCs by transient ischaemia-reperfusion, were observed in mouse hindlimbs subjected to chronic ischaemia. This response demonstrates the relevance of the findings to peripheral arterial disease, in which patients experience transient exercise-induced ischaemia known as claudication.These findings demonstrate that chronically inflamed tissues show an altered profile and altered mechanisms of acute inflammatory responses, and identify tissue-resident MDCs as potential therapeutic targets. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

SU-F-T-685: Evaluation of Tumor Hypoxic Fraction Using Serial Volumetric Imaging During Radiation Therapy

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

Chvetsov, A

Purpose: To develop a tumor response model which could be uses to compute tumor hypoxic fraction using serial volumetric tumor imaging. This algorithm may be used for treatment response assessment and also for guidance of more expensive PET imaging of hypoxia. Methods: Previously developed two-level cell population tumor response model was modified to include a third cell level describing hypoxic and necrotic cells. This third level was considered constant value during radiotherapy treatment; therefore, inclusion additional parameter did not compromise stability of model fitting to imaging data. Fitting the model to serial volumetric imaging data was performed using a leastmore » squares objective function and simulated annealing algorithm. The problem of reconstruction of radiobiological parameters from serial imaging data was considered as inverse ill-posed problem described by the Fredholm integral equation of the first kind. Variational regularization was used to stabilize solutions. Results: To evaluate performance of the algorithm, we used a set of serial CT imaging data on tumor-volume for 14 head and neck cancer patients. The hypoxic fractions were reconstructed for each patient and the distribution of hypoxic fractions was compared to the distribution of initial hypoxic fractions previously measured using histograph. The measured and reconstructed from imaging data distributions of hypoxic fractions are in good agreement. The reconstructed distribution of cell surviving fraction was also in better agreement with in vitro data than previously obtained using the two-level cell population model. Conclusion: Our results indicate that it is possible to evaluate the initial hypoxic tumor fraction using serial volumetric imaging and a tumor response model. This algorithm can be used for treatment response assessment and guidance of more expensive PET imaging.« less

Persistent activation of an innate immune axis translates respiratory viral infection into chronic lung disease

PubMed Central

Kim, Edy Y.; Battaile, John T.; Patel, Anand C.; You, Yingjian; Agapov, Eugene; Grayson, Mitchell H.; Benoit, Loralyn A.; Byers, Derek E.; Alevy, Yael; Tucker, Jennifer; Swanson, Suzanne; Tidwell, Rose; Tyner, Jeffrey W.; Morton, Jeffrey D.; Castro, Mario; Polineni, Deepika; Patterson, G. Alexander; Schwendener, Reto A.; Allard, John D.; Peltz, Gary; Holtzman, Michael J.

2008-01-01

To understand the pathogenesis of chronic inflammatory disease, we analyzed an experimental mouse model of a chronic lung disease that resembles asthma and chronic obstructive pulmonary disease (COPD) in humans. In this model, chronic lung disease develops after infection with a common type of respiratory virus is cleared to trace levels of noninfectious virus. Unexpectedly, the chronic inflammatory disease arises independently of an adaptive immune response and is driven by IL-13 produced by macrophages stimulated by CD1d-dependent TCR-invariant NKT cells. This innate immune axis is also activated in the lungs of humans with chronic airway disease due to asthma or COPD. These findings provide new insight into the pathogenesis of chronic inflammatory disease with the discovery that the transition from respiratory viral infection into chronic lung disease requires persistent activation of a novel NKT cell-macrophage innate immune axis. PMID:18488036

Curved reformat of the paediatric brain MRI into a 'flat-earth map' - standardised method for demonstrating cortical surface atrophy resulting from hypoxic-ischaemic encephalopathy.

PubMed

Simpson, Ewan; Andronikou, Savvas; Vedajallam, Schadie; Chacko, Anith; Thai, Ngoc Jade

2016-09-01

Hypoxic-ischaemic encephalopathy is optimally imaged with brain MRI in the neonatal period. However neuroimaging is often also performed later in childhood (e.g., when parents seek compensation in cases of alleged birth asphyxia). We describe a standardised technique for creating two curved reconstructions of the cortical surface to show the characteristic surface changes of hypoxic-ischaemic encephalopathy in children imaged after the neonatal period. The technique was applied for 10 cases of hypoxic-ischaemic encephalopathy and also for age-matched healthy children to assess the visibility of characteristic features of hypoxic-ischaemic encephalopathy. In the abnormal brains, fissural or sulcal widening was seen in all cases and ulegyria was identifiable in 7/10. These images could be used as a visual aid for communicating MRI findings to clinicians and other interested parties.

Genetically engineered mouse models for studying inflammatory bowel disease.

PubMed

Mizoguchi, Atsushi; Takeuchi, Takahito; Himuro, Hidetomo; Okada, Toshiyuki; Mizoguchi, Emiko

2016-01-01

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition that is mediated by very complex mechanisms controlled by genetic, immune, and environmental factors. More than 74 kinds of genetically engineered mouse strains have been established since 1993 for studying IBD. Although mouse models cannot fully reflect human IBD, they have provided significant contributions for not only understanding the mechanism, but also developing new therapeutic means for IBD. Indeed, 20 kinds of genetically engineered mouse models carry the susceptibility genes identified in human IBD, and the functions of some other IBD susceptibility genes have also been dissected out using mouse models. Cutting-edge technologies such as cell-specific and inducible knockout systems, which were recently employed to mouse IBD models, have further enhanced the ability of investigators to provide important and unexpected rationales for developing new therapeutic strategies for IBD. In this review article, we briefly introduce 74 kinds of genetically engineered mouse models that spontaneously develop intestinal inflammation. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Renal Impairment with Sublethal Tubular Cell Injury in a Chronic Liver Disease Mouse Model

PubMed Central

Ishida, Tokiko; Kotani, Hirokazu; Miyao, Masashi; Kawai, Chihiro; Jemail, Leila; Abiru, Hitoshi; Tamaki, Keiji

2016-01-01

The pathogenesis of renal impairment in chronic liver diseases (CLDs) has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy), autophagy, and oxidative stress were studied longitudinally in DDC- and standard diet–fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the pathophysiological mechanisms of sublethal tubular cell injury. PMID:26752420

Antidepressant-like Responses to Lithium in Genetically Diverse Mouse Strains

PubMed Central

Can, Adem; Blackwell, Robert A.; Piantadosi, Sean C.; Dao, David T.; O’Donnell, Kelley C.; Gould, Todd D.

2011-01-01

A mood stabilizing and antidepressant response to lithium is only found in a subgroup of bipolar disorder and depression patients. Identifying strains of mice that are responsive and non-responsive to lithium may elucidate genomic and other biological factors that play a role in lithium responsiveness. Mouse strains were tested in the forced swim, tail suspension, and open field tests after acute and chronic systemic, and intracerebroventricular and chronic lithium treatments. Serum and brain lithium levels were measured. Three (129S6/SvEvTac, C3H/HeNHsd, C57BL/6J) of the eight inbred strains tested, and one (CD-1) of the three outbred strains, showed an antidepressant-like response in the forced swim test following acute systemic administration of lithium. The three responsive inbred strains, as well as the DBA/2J strain, were also responsive in the forced swim test after chronic administration of lithium. However, in the tail suspension test, acute lithium resulted in an antidepressant-like effect only in C3H/HeNHsd mice. Only C57BL/6J and DBA/2J were responsive in the tail suspension test after chronic administration of lithium. Intracerebroventricular lithium administration resulted in a similar response profile in BALB/cJ (non-responsive) and C57BL/6J (responsive) strains. Serum and brain lithium concentrations demonstrated that behavioral results were not due to differential pharmacokinetics of lithium in individual strains, suggesting that genetic factors likely regulate responsiveness to lithium. Our results indicate that responsiveness to lithium in tests of antidepressant efficacy varies among genetically diverse mouse strains. These results will assist in identifying genomic factors associated with lithium responsiveness and the mechanisms of lithium action. PMID:21306560

Chronic paroxetine treatment prevents disruption of methamphetamine-sensitive circadian oscillator in a transgenic mouse model of Huntington's disease.

PubMed

Ouk, Koliane; Aungier, Juliet; Cuesta, Marc; Morton, A Jennifer

2018-03-15

Circadian abnormalities seen in Huntington's disease (HD) patients are recapitulated in several HD transgenic mouse models. In mice, alongside the master clock located in the suprachiasmatic nucleus (SCN), two other oscillators may influence circadian behaviour. These are the food-entrainable oscillator (FEO) and the methamphetamine-sensitive circadian oscillator (MASCO). SCN- and MASCO- (but not FEO-) driven rhythms are progressively disrupted in the R6/2 mouse model of HD. MASCO-driven rhythms are induced by chronic treatment with low dose of methamphetamine and characterised by an increase in period length to greater than 24 h. Interestingly, the rhythms mediated by MASCO deteriorate earlier than those mediated by the SCN in R6/2 mice. Here, we used a pharmacological strategy to investigate the mechanisms underlying MASCO-driven rhythms in WT mice. In contrast to methamphetamine, chronic cocaine was ineffective in generating a MASCO-like component of activity although it markedly increased locomotion. Furthermore, neither blocking dopamine (DA) receptors (with the DA antagonist haloperidol) nor blocking neurotransmission by inhibiting the activity of vesicular monoamine transporter (with reserpine) prevented the expression of the MASCO-driven rhythms, although both treatments downregulated locomotor activity. Interestingly, chronic treatment with paroxetine, a serotonin-specific reuptake inhibitor commonly used as antidepressant in HD, was able to restore the expression of MASCO-driven rhythms in R6/2 mice. Thus, MASCO-driven rhythms appear to be mediated by both serotoninergic and dopaminergic systems. This supports the idea that abnormalities in MASCO output may contribute to both the HD circadian and psychiatric phenotype. Copyright © 2017 Elsevier Ltd. All rights reserved.

S-adenosylmethionine reduces airway inflammation and fibrosis in a murine model of chronic severe asthma via suppression of oxidative stress.

PubMed

Yoon, Sun-Young; Hong, Gyong Hwa; Kwon, Hyouk-Soo; Park, Sunjoo; Park, So Young; Shin, Bomi; Kim, Tae-Bum; Moon, Hee-Bom; Cho, You Sook

2016-06-03

Increased oxidative stress has an important role in asthmatic airway inflammation and remodeling. A potent methyl donor, S-adenosylmethionine (SAMe), is known to protect against tissue injury and fibrosis through modulation of oxidative stress. The aim of this study was to evaluate the effect of SAMe on airway inflammation and remodeling in a murine model of chronic asthma. A mouse model was generated by repeated intranasal challenge with ovalbumin and Aspergillus fungal protease twice a week for 8 weeks. SAMe was orally administered every 24 h for 8 weeks. We performed bronchoalveolar lavage (BAL) fluid analysis and histopathological examination. The levels of various cytokines and 4-hydroxy-2-nonenal (HNE) were measured in the lung tissue. Cultured macrophages and fibroblasts were employed to evaluate the underlying anti-inflammatory and antifibrotic mechanisms of SAMe. The magnitude of airway inflammation and fibrosis, as well as the total BAL cell counts, were significantly suppressed in the SAMe-treated groups. A reduction in T helper type 2 pro-inflammatory cytokines and HNE levels was observed in mouse lung tissue after SAMe administration. Macrophages cultured with SAMe also showed reduced cellular oxidative stress and pro-inflammatory cytokine production. Moreover, SAMe treatment attenuated transforming growth factor-β (TGF-β)-induced fibronectin expression in cultured fibroblasts. SAMe had a suppressive effect on airway inflammation and fibrosis in a mouse model of chronic asthma, at least partially through the attenuation of oxidative stress and TGF-β-induced fibronectin expression. The results of this study suggest a potential role for SAMe as a novel therapeutic agent in chronic asthma.

Essential Role of Protein-tyrosine Phosphatase 1B in the Modulation of Insulin Signaling by Acetaminophen in Hepatocytes*

PubMed Central

Mobasher, Maysa Ahmed; de Toro-Martín, Juan; González-Rodríguez, Águeda; Ramos, Sonia; Letzig, Lynda G.; James, Laura P.; Muntané, Jordi; Álvarez, Carmen; Valverde, Ángela M.

2014-01-01

Many drugs are associated with the development of glucose intolerance or deterioration in glycemic control in patients with pre-existing diabetes. We have evaluated the cross-talk between signaling pathways activated by acetaminophen (APAP) and insulin signaling in hepatocytes with or without expression of the protein-tyrosine phosphatase 1B (PTP1B) and in wild-type and PTP1B-deficient mice chronically treated with APAP. Human primary hepatocytes, Huh7 hepatoma cells with silenced PTP1B, mouse hepatocytes from wild-type and PTP1B-deficient mice, and a mouse model of chronic APAP treatment were used to examine the mechanisms involving PTP1B in the effects of APAP on glucose homeostasis and hepatic insulin signaling. In APAP-treated human hepatocytes at concentrations that did not induce death, phosphorylation of JNK and PTP1B expression and enzymatic activity were increased. APAP pretreatment inhibited activation of the early steps of insulin signaling and decreased Akt phosphorylation. The effects of APAP in insulin signaling were prevented by suramin, a PTP1B inhibitor, or rosiglitazone that decreased PTP1B levels. Likewise, PTP1B deficiency in human or mouse hepatocytes protected against APAP-mediated impairment in insulin signaling. These signaling pathways were modulated in mice with chronic APAP treatment, resulting in protection against APAP-mediated hepatic insulin resistance and alterations in islet alpha/beta cell ratio in PTP1B−/− mice. Our results demonstrate negative cross-talk between signaling pathways triggered by APAP and insulin signaling in hepatocytes, which is in part mediated by PTP1B. Moreover, our in vivo data suggest that chronic use of APAP may be associated with insulin resistance in the liver. PMID:25204659

Hemoglobin induced lung vascular oxidation, inflammation, and remodeling contributes to the progression of hypoxic pulmonary hypertension and is attenuated in rats with repeat dose haptoglobin administration

PubMed Central

Baek, Jin Hyen; Hassell, Kathryn; Nuss, Rachelle; Eigenberger, Paul; Lisk, Christina; Loomis, Zoe; Maltzahn, Joanne; Stenmark, Kurt R; Nozik-Grayck, Eva

2015-01-01

Objective Haptoglobin (Hp) is an approved treatment in Japan with indications for trauma, burns and massive transfusion related hemolysis. Additional case reports suggest uses in other acute hemolytic events that lead to acute kidney injury. However, Hp's protective effects on the pulmonary vasculature have not been evaluated within the context of mitigating the consequences of chronic hemoglobin (Hb) exposure in the progression of pulmonary hypertension (PH) secondary to hemolytic diseases. This study was performed to assess the utility of chronic Hp therapy in a preclinical model of Hb and hypoxia mediated PH. Approach and results Rats were simultaneously exposed to chronic Hb-infusion (35 mg per day) and hypobaric hypoxia for five weeks in the presence or absence of Hp treatment (90 mg/kg twice a week). Hp inhibited the Hb plus hypoxia-mediated non-heme iron accumulation in lung and heart tissue, pulmonary vascular inflammation and resistance, and right ventricular hypertrophy, which suggest a positive impact on impeding the progression of PH. In addition, Hp therapy was associated with a reduction in critical mediators of PH, including lung adventitial macrophage population and endothelial ICAM-1 expression. Conclusions By preventing Hb-mediated pathology, Hp infusions: (1) demonstrate a critical role for Hb in vascular remodeling associated with hypoxia; and (2) suggest a novel therapy for chronic hemolysis associated PH. PMID:25656991

Hemoglobin-induced lung vascular oxidation, inflammation, and remodeling contribute to the progression of hypoxic pulmonary hypertension and is attenuated in rats with repeated-dose haptoglobin administration.

PubMed

Irwin, David C; Baek, Jin Hyen; Hassell, Kathryn; Nuss, Rachelle; Eigenberger, Paul; Lisk, Christina; Loomis, Zoe; Maltzahn, Joanne; Stenmark, Kurt R; Nozik-Grayck, Eva; Buehler, Paul W

2015-05-01

Haptoglobin (Hp) is an approved treatment in Japan for trauma, burns, and massive transfusion-related hemolysis. Additional case reports suggest uses in other acute hemolytic events that lead to acute kidney injury. However, Hp's protective effects on the pulmonary vasculature have not been evaluated within the context of mitigating the consequences of chronic hemoglobin (Hb) exposure in the progression of pulmonary hypertension (PH) secondary to hemolytic diseases. This study was performed to assess the utility of chronic Hp therapy in a preclinical model of Hb and hypoxia-mediated PH. Rats were simultaneously exposed to chronic Hb infusion (35 mg per day) and hypobaric hypoxia for 5 weeks in the presence or absence of Hp treatment (90 mg/kg twice a week). Hp inhibited the Hb plus hypoxia-mediated nonheme iron accumulation in lung and heart tissue, pulmonary vascular inflammation and resistance, and right-ventricular hypertrophy, which suggests a positive impact on impeding the progression of PH. In addition, Hp therapy was associated with a reduction in critical mediators of PH, including lung adventitial macrophage population and endothelial ICAM-1 expression. By preventing Hb-mediated pathology, Hp infusions: (1) demonstrate a critical role for Hb in vascular remodeling associated with hypoxia and (2) suggest a novel therapy for chronic hemolysis-associated PH. Copyright © 2015 Elsevier Inc. All rights reserved.

The Role of Protein Radicals in Chronic Neuroimmune Dysfunction and Neuropathology in Response to a Multiple-Hit Model of Gulf War Exposure

DTIC Science & Technology

2014-10-01

potential neurotoxicants and triggers of inflammation, such as persistent peripheral inflammation and the organophosphate pesticide chlorpyrifos (CPF...War Illness Mouse Model, Chlorpyrifos , LPS, NF-KB p50, microglia, chronic neuroinflammation, serum markers, neuropathology 16. SECURITY...neurotoxicants and triggers of inflammation, such as persistent infections, and the organophosphate pesticide chlorpyrifos (CPF) may interact to

Unpredictable chronic mild stress differentially impairs social and contextual discrimination learning in two inbred mouse strains.

PubMed

van Boxelaere, Michiel; Clements, Jason; Callaerts, Patrick; D'Hooge, Rudi; Callaerts-Vegh, Zsuzsanna

2017-01-01

Alterations in the social and cognitive domain are considered important indicators for increased disability in many stress-related disorders. Similar impairments have been observed in rodents chronically exposed to stress, mimicking potential endophenotypes of stress-related psychopathologies such as major depression disorder (MDD), anxiety, conduct disorder, and posttraumatic stress disorder (PTSD). Data from numerous studies suggest that deficient plasticity mechanisms in hippocampus (HC) and prefrontal cortex (PFC) might underlie these social and cognitive deficits. Specifically, stress-induced deficiencies in neural plasticity have been associated with a hypodopaminergic state and reduced neural plasticity persistence. Here we assessed the effects of unpredictable chronic mild stress (UCMS) on exploratory, social and cognitive behavior of females of two inbred mouse strains (C57BL/6J and DBA/2J) that differ in their dopaminergic profile. Exposure to chronic stress resulted in impaired circadian rhythmicity, sociability and social cognition in both inbred strains, but differentially affected activity patterns and contextual discrimination performance. These stress-induced behavioral impairments were accompanied by reduced expression levels of brain derived neurotrophic factor (BDNF) in the prefrontal cortex. The strain-specific cognitive impairment was coexistent with enhanced plasma corticosterone levels and reduced expression of genes related to dopamine signaling in hippocampus. These results underline the importance of assessing different strains with multiple test batteries to elucidate the neural and genetic basis of social and cognitive impairments related to chronic stress.

The radiosensitivity of a murine fibrosarcoma as measured by three cell survival assays.

PubMed Central

Rice, L.; Urano, M.; Suit, H. D.

1980-01-01

The radiation sensitivity of a weakly immunogenic spontaneous fibrosarcoma of the C3Hf/Sed mouse (designated FSa-II) was assessed by three in vivo cell survival methods: end-point dilution (TD50) assay, lung colony (LC) assay, and agar diffusion chamber (ADC) assay. The hypoxic fraction of this tumour was also determined by the ADC method. Although there was a good agreement of the cell survival data between the ADC and LC methods, the TD50 method yielded a considerably less steep cell survival curve. Beneficial aspects and limitations of each assay are discussed. In addition, the use of the ADC method for the growth of xenogeneic cell lines and a preliminary experiment with human tumour cells in non-immunosuppressed hosts suggest that this method may be a valuable adjunct for studying the growth and therapeutic responses of human tumour cells. PMID:6932931

HIF-2α dictates the susceptibility of pancreatic cancer cells to TRAIL by regulating survivin expression

PubMed Central

Harashima, Nanae; Takenaga, Keizo; Akimoto, Miho; Harada, Mamoru

2017-01-01

Cancer cells develop resistance to therapy by adapting to hypoxic microenvironments, and hypoxia-inducible factors (HIFs) play crucial roles in this process. We investigated the roles of HIF-1α and HIF-2α in cancer cell death induced by tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) using human pancreatic cancer cell lines. siRNA-mediated knockdown of HIF-2α, but not HIF-1α, increased susceptibility of two pancreatic cancer cell lines, Panc-1 and AsPC-1, to TRAIL in vitro under normoxic and hypoxic conditions. The enhanced sensitivity to TRAIL was also observed in vivo. This in vitro increased TRAIL sensitivity was observed in other three pancreatic cancer cell lines. An array assay of apoptosis-related proteins showed that knockdown of HIF-2α decreased survivin expression. Additionally, survivin promoter activity was decreased in HIF-2α knockdown Panc-1 cells and HIF-2α bound to the hypoxia-responsive element in the survivin promoter region. Conversely, forced expression of the survivin gene in HIF-2α shRNA-expressing Panc-1 cells increased resistance to TRAIL. In a xenograft mouse model, the survivin suppressant YM155 sensitized Panc-1 cells to TRAIL. Collectively, our results indicate that HIF-2α dictates the susceptibility of human pancreatic cancer cell lines, Panc-1 and AsPC-1, to TRAIL by regulating survivin expression transcriptionally, and that survivin could be a promising target to augment the therapeutic efficacy of death receptor-targeting anti-cancer therapy. PMID:28476028

A novel mouse model of high flow-induced pulmonary hypertension-surgically induced by right pulmonary artery ligation.

PubMed

Zhang, Anchen; Wang, Hongfei; Wang, Shengwei; Huang, Xiaofan; Ye, Ping; Du, Xinling; Xia, Jiahong

2017-02-01

This study sought to establish a new model of high-flow pulmonary hypertension (PH) in mice. This model may be useful for studies seeking to reduce the pulmonary vascular resistance and delay the development of PH caused by congenital heart disease. The right pulmonary artery was ligated via a right posterolateral thoracotomy. Pulmonary hemodynamics was evaluated by right heart catheterization immediately after ligation and at 2, 4, 8, and 12 wk postoperatively. The right ventricle (RV) and the left ventricle (LV) with septum (S) were weighed to calculate the RV/(LV + S) ratio as an index of right ventricular hypertrophy. Morphologic changes in the left lungs were analyzed, and percentages of muscularized pulmonary vessels were assessed by hematoxylin and eosin, elastica van Gieson and alpha-smooth muscle actin staining. All the study data were compared with data from a model of PH generated by hypoxic stimulation. A pulmonary hypertensive state was successfully induced by 2 wk after surgery. However, the morphologic analysis demonstrated that pulmonary vascular muscularization, as evaluated using right ventricular systolic pressure and RV/(LV + S), was not significantly increased until 4 wk postoperatively. When mice from the new model and the hypoxic model were compared, no significant differences were observed in any of the evaluated indices. High-flow PH can be induced within 4 wk after ligation of the right pulmonary artery, which is easily performed in mice. Such mice can be used as a model of high-flow PH. Copyright © 2016 Elsevier Inc. All rights reserved.

MRI evaluation and functional assessment of brain injury after hypoxic ischemia in neonatal mice.

PubMed

Adén, Ulrika; Dahlberg, Viktoria; Fredholm, Bertil B; Lai, Li-Ju; Chen, Zhengguan; Bjelke, Börje

2002-05-01

Severe perinatal asphyxia is an important cause of brain injury in the newborn infant. We examined early events after hypoxic ischemia (HI) in the 7-day-old mouse brain by MRI and related them to long-term functional effects and histopathology in the same animals at 4 to 5 weeks of age. HI was induced in 7-day-old CD1 mice by exposure to 8% oxygen for 30 minutes after occlusion of the left common carotid artery. The resulting unilateral focal lesion was evaluated in vivo by MRI (T2 maps and apparent diffusion coefficient maps) at 3, 6, and 24 hours and 5 days after hypoxia. Locomotion and sensorimotor function were analyzed after 3 weeks. Four weeks after HI, the mice were killed, and cresyl violet-stained brain sections were examined morphologically. A decrease in apparent diffusion coefficient values in cortex on the affected side was found at 3 hours after HI. T2 values were significantly increased after 6 hours and remained so for 5 days. Maximal size of the lesion was attained at 3 to 6 hours after HI and declined thereafter. Animals with MRI-detected lesions had decreased forward locomotion, performed worse than controls in the beam-walking test, and showed a unilateral hypotrophy in the cresyl violet-stained brain sections 4 weeks later. The temporal progression of the damage after HI in 7-day-old mice differs from that of the adult brain as judged by MRI. The early lesions detected by MRI were related to functional impairments for these mice in near-adult life.

DOR activation inhibits anoxic/ischemic Na+ influx through Na+ channels via PKC mechanisms in the cortex.

PubMed

Chao, Dongman; He, Xiaozhou; Yang, Yilin; Bazzy-Asaad, Alia; Lazarus, Lawrence H; Balboni, Gianfranco; Kim, Dong H; Xia, Ying

2012-08-01

Activation of delta-opioid receptors (DOR) is neuroprotective against hypoxic/ischemic injury in the cortex, which is at least partially related to its action against hypoxic/ischemic disruption of ionic homeostasis that triggers neuronal injury. Na(+) influx through TTX-sensitive voltage-gated Na(+) channels may be a main mechanism for hypoxia-induced disruption of K(+) homeostasis, with DOR activation attenuating the disruption of ionic homeostasis by targeting voltage-gated Na(+) channels. In the present study we examined the role of DOR in the regulation of Na(+) influx in anoxia and simulated ischemia (oxygen-glucose deprivation) as well as the effect of DOR activation on the Na(+) influx induced by a Na(+) channel opener without anoxic/ischemic stress and explored a potential PKC mechanism underlying the DOR action. We directly measured extracellular Na(+) activity in mouse cortical slices with Na(+) selective electrodes and found that (1) anoxia-induced Na(+) influx occurred mainly through TTX-sensitive Na(+) channels; (2) DOR activation inhibited the anoxia/ischemia-induced Na(+) influx; (3) veratridine, a Na(+) channel opener, enhanced the anoxia-induced Na(+) influx; this could be attenuated by DOR activation; (4) DOR activation did not reduce the anoxia-induced Na(+) influx in the presence of chelerythrine, a broad-spectrum PKC blocker; and (5) DOR effects were blocked by PKCβII peptide inhibitor, and PKCθ pseudosubstrate inhibitor, respectively. We conclude that DOR activation inhibits anoxia-induced Na(+) influx through Na(+) channels via PKC (especially PKCβII and PKCθ isoforms) dependent mechanisms in the cortex. Copyright © 2012 Elsevier Inc. All rights reserved.

Serine protease activity contributes to control of Mycobacterium tuberculosis in hypoxic lung granulomas in mice

PubMed Central

Reece, Stephen T.; Loddenkemper, Christoph; Askew, David J.; Zedler, Ulrike; Schommer-Leitner, Sandra; Stein, Maik; Mir, Fayaz Ahmad; Dorhoi, Anca; Mollenkopf, Hans-Joachim; Silverman, Gary A.; Kaufmann, Stefan H.E.

2010-01-01

The hallmark of human Mycobacterium tuberculosis infection is the presence of lung granulomas. Lung granulomas can have different phenotypes, with caseous necrosis and hypoxia present within these structures during active tuberculosis. Production of NO by the inducible host enzyme NOS2 is a key antimycobacterial defense mechanism that requires oxygen as a substrate; it is therefore likely to perform inefficiently in hypoxic regions of granulomas in which M. tuberculosis persists. Here we have used Nos2–/– mice to investigate host-protective mechanisms within hypoxic granulomas and identified a role for host serine proteases in hypoxic granulomas in determining outcome of disease. Nos2–/– mice reproduced human-like granulomas in the lung when infected with M. tuberculosis in the ear dermis. The granulomas were hypoxic and contained large amounts of the serine protease cathepsin G and clade B serine protease inhibitors (serpins). Extrinsic inhibition of serine protease activity in vivo resulted in distorted granuloma structure, extensive hypoxia, and increased bacterial growth in this model. These data suggest that serine protease activity acts as a protective mechanism within hypoxic regions of lung granulomas and present a potential new strategy for the treatment of tuberculosis. PMID:20679732

The Hog1 Mitogen-Activated Protein Kinase Mediates a Hypoxic Response in Saccharomyces cerevisiae

PubMed Central

Hickman, Mark J.; Spatt, Dan; Winston, Fred

2011-01-01

We have studied hypoxic induction of transcription by studying the seripauperin (PAU) genes of Saccharomyces cerevisiae. Previous studies showed that PAU induction requires the depletion of heme and is dependent upon the transcription factor Upc2. We have now identified additional factors required for PAU induction during hypoxia, including Hog1, a mitogen-activated protein kinase (MAPK) whose signaling pathway originates at the membrane. Our results have led to a model in which heme and ergosterol depletion alters membrane fluidity, thereby activating Hog1 for hypoxic induction. Hypoxic activation of Hog1 is distinct from its previously characterized response to osmotic stress, as the two conditions cause different transcriptional consequences. Furthermore, Hog1-dependent hypoxic activation is independent of the S. cerevisiae general stress response. In addition to Hog1, specific components of the SAGA coactivator complex, including Spt20 and Sgf73, are also required for PAU induction. Interestingly, the mammalian ortholog of Spt20, p38IP, has been previously shown to interact with the mammalian ortholog of Hog1, p38. Taken together, our results have uncovered a previously unknown hypoxic-response pathway that may be conserved throughout eukaryotes. PMID:21467572

Medicinal electronomics bricolage design of hypoxia-targeting antineoplastic drugs and invention of boron tracedrugs as innovative future-architectural drugs.

PubMed

Hori, Hitoshi; Uto, Yoshihiro; Nakata, Eiji

2010-09-01

We describe herein for the first time our medicinal electronomics bricolage design of hypoxia-targeting antineoplastic drugs and boron tracedrugs as newly emerging drug classes. A new area of antineoplastic drugs and treatments has recently focused on neoplastic cells of the tumor environment/microenvironment involving accessory cells. This tumor hypoxic environment is now considered as a major factor that influences not only the response to antineoplastic therapies but also the potential for malignant progression and metastasis. We review our medicinal electronomics bricolage design of hypoxia-targeting drugs, antiangiogenic hypoxic cell radiosensitizers, sugar-hybrid hypoxic cell radiosensitizers, and hypoxia-targeting 10B delivery agents, in which we design drug candidates based on their electronic structures obtained by molecular orbital calculations, not based solely on pharmacophore development. These drugs include an antiangiogenic hypoxic cell radiosensitizer TX-2036, a sugar-hybrid hypoxic cell radiosensitizer TX-2244, new hypoxia-targeting indoleamine 2,3-dioxygenase (IDO) inhibitors, and a hypoxia-targeting BNCT agent, BSH (sodium borocaptate-10B)-hypoxic cytotoxin tirapazamine (TPZ) hybrid drug TX-2100. We then discuss the concept of boron tracedrugs as a new drug class having broad potential in many areas.

NLP-1: a DNA intercalating hypoxic cell radiosensitizer and cytotoxin

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

Panicucci, R.; Heal, R.; Laderoute, K.

The 2-nitroimidazole linked phenanthridine, NLP-1 (5-(3-(2-nitro-1-imidazoyl)-propyl)-phenanthridinium bromide), was synthesized with the rationale of targeting the nitroimidazole to DNA via the phenanthridine ring. The drug is soluble in aqueous solution (greater than 25 mM) and stable at room temperature. It binds to DNA with a binding constant 1/30 that of ethidium bromide. At a concentration of 0.5 mM, NLP-1 is 8 times more toxic to hypoxic than aerobic cells at 37 degrees C. This concentration is 40 times less than the concentration of misonidazole, a non-intercalating 2-nitroimidazole, required for the same degree of hypoxic cell toxicity. The toxicity of NLP-1 ismore » reduced at least 10-fold at 0 degrees C. Its ability to radiosensitize hypoxic cells is similar to misonidazole at 0 degrees C. Thus the putative targeting of the 2-nitroimidazole, NLP-1, to DNA, via its phenanthridine group, enhances its hypoxic toxicity, but not its radiosensitizing ability under the present test conditions. NLP-1 represents a lead compound for intercalating 2-nitroimidazoles with selective toxicity for hypoxic cells.« less

Complementary proteomic approaches reveal mitochondrial dysfunction, immune and inflammatory dysregulation in a mouse model of Gulf War Illness.

PubMed

Zakirova, Zuchra; Reed, Jon; Crynen, Gogce; Horne, Lauren; Hassan, Samira; Mathura, Venkatarajan; Mullan, Michael; Crawford, Fiona; Ait-Ghezala, Ghania

2017-09-01

Long-term consequences of combined pyridostigmine bromide (PB) and permethrin (PER) exposure in C57BL6/J mice using a well-characterized mouse model of exposure to these Gulf War (GW) agents were explored at the protein level. We used orthogonal proteomic approaches to identify pathways that are chronically impacted in the mouse CNS due to semiacute GW agent exposure early in life. These analyses were performed on soluble and membrane-bound protein fractions from brain samples using two orthogonal isotopic labeling LC-MS/MS proteomic approaches-stable isotope dimethyl labeling and iTRAQ. The use of these approaches allowed for greater coverage of proteins than was possible by either one alone and revealed both distinct and overlapping datasets. This combined analysis identified changes in several mitochondrial, as well as immune and inflammatory pathways after GW agent exposure. The work discussed here provides insight into GW agent exposure dependent mechanisms that adversely affect mitochondrial function and immune and inflammatory regulation. Collectively, our work identified key pathways which were chronically impacted in the mouse CNS following acute GW agent exposure, this may lead to the identification of potential targets for therapeutic intervention in the future. Long-term consequences of combined PB and PER exposure in C57BL6/J mice using a well-characterized mouse model of exposure to these GW agents were explored at the protein level. Expanding on earlier work, we used orthogonal proteomic approaches to identify pathways that are chronically impacted in the mouse CNS due to semiacute GW agent exposure early in life. These analyses were performed on soluble and membrane-bound protein fractions from brain samples using two orthogonal isotopic labeling LC-MS/MS proteomic approaches-stable isotope dimethyl labeling and iTRAQ. The use of these approaches allowed for greater coverage of proteins than was possible by either one alone and revealed both distinct and overlapping datasets. This combined analysis identified changes in several mitochondrial, as well as immune and inflammatory pathways after GW agent exposure. The work discussed here provides insight into GW agent exposure dependent mechanisms that adversely affect mitochondrial function and immune and inflammatory regulation at 5 months postexposure to PB + PER. © 2017 The Authors. PROTEOMICS - Clinical Applications published by WILEY-VCH Verlag GmbH & Co. KGaA.

Complementary proteomic approaches reveal mitochondrial dysfunction, immune and inflammatory dysregulation in a mouse model of Gulf War Illness

PubMed Central

Zakirova, Zuchra; Reed, Jon; Crynen, Gogce; Horne, Lauren; Hassan, Samira; Mathura, Venkatarajan; Mullan, Michael; Crawford, Fiona

2017-01-01

Purpose Long‐term consequences of combined pyridostigmine bromide (PB) and permethrin (PER) exposure in C57BL6/J mice using a well‐characterized mouse model of exposure to these Gulf War (GW) agents were explored at the protein level. Experimental design We used orthogonal proteomic approaches to identify pathways that are chronically impacted in the mouse CNS due to semiacute GW agent exposure early in life. These analyses were performed on soluble and membrane‐bound protein fractions from brain samples using two orthogonal isotopic labeling LC‐MS/MS proteomic approaches—stable isotope dimethyl labeling and iTRAQ. Results The use of these approaches allowed for greater coverage of proteins than was possible by either one alone and revealed both distinct and overlapping datasets. This combined analysis identified changes in several mitochondrial, as well as immune and inflammatory pathways after GW agent exposure. Conclusions and clinical relevance The work discussed here provides insight into GW agent exposure dependent mechanisms that adversely affect mitochondrial function and immune and inflammatory regulation. Collectively, our work identified key pathways which were chronically impacted in the mouse CNS following acute GW agent exposure, this may lead to the identification of potential targets for therapeutic intervention in the future. Long‐term consequences of combined PB and PER exposure in C57BL6/J mice using a well‐characterized mouse model of exposure to these GW agents were explored at the protein level. Expanding on earlier work, we used orthogonal proteomic approaches to identify pathways that are chronically impacted in the mouse CNS due to semiacute GW agent exposure early in life. These analyses were performed on soluble and membrane‐bound protein fractions from brain samples using two orthogonal isotopic labeling LC‐MS/MS proteomic approaches—stable isotope dimethyl labeling and iTRAQ. The use of these approaches allowed for greater coverage of proteins than was possible by either one alone and revealed both distinct and overlapping datasets. This combined analysis identified changes in several mitochondrial, as well as immune and inflammatory pathways after GW agent exposure. The work discussed here provides insight into GW agent exposure dependent mechanisms that adversely affect mitochondrial function and immune and inflammatory regulation at 5 months postexposure to PB + PER. PMID:28371386

Hypoxia enhances the interaction between pancreatic stellate cells and cancer cells via increased secretion of connective tissue growth factor.

PubMed

Eguchi, Daiki; Ikenaga, Naoki; Ohuchida, Kenoki; Kozono, Shingo; Cui, Lin; Fujiwara, Kenji; Fujino, Minoru; Ohtsuka, Takao; Mizumoto, Kazuhiro; Tanaka, Masao

2013-05-01

Pancreatic cancer (PC), a hypovascular tumor, thrives under hypoxic conditions. Pancreatic stellate cells (PSCs) promote PC progression by secreting soluble factors, but their functions in hypoxia are poorly understood. This study aimed to clarify the effects of hypoxic conditions on the interaction between PC cells and PSCs. We isolated human PSCs from fresh pancreatic ductal adenocarcinomas and analyzed functional differences in PSCs between normoxia (21% O2) and hypoxia (1% O2), including expression of various factors related to tumor-stromal interactions. We particularly analyzed effects on PC invasiveness of an overexpressed molecule-connective tissue growth factor (CTGF)-in PSCs under hypoxic conditions, using RNA interference techniques. Conditioned media from hypoxic PSCs enhanced PC cell invasiveness more intensely than that from normoxic PSCs (P < 0.01). When co-cultured with PSCs, PC cell invasion was more enhanced under hypoxia than under normoxia (P < 0.05). Among various soluble factors, which were related to invasiveness, CTGF was one of the overexpressed molecules in hypoxic PSCs. A higher level of CTGF expression was also found in supernatant of hypoxic PSCs than in supernatant of normoxic PSCs. PC cell invasiveness was reduced by CTGF knockdown in hypoxic PSCs co-cultured with PC cells (P < 0.05). Hypoxia induces PSCs' secretion of CTGF, leading to enhancement of PC invasiveness. CTGF derived from hypoxia-stimulated PSCs may be a new therapeutic target for pancreatic cancer. Copyright © 2013 Elsevier Inc. All rights reserved.

Determination of concentration and molar absorptivity of hypochlorous acid and hypobromous acid species by hydrogen peroxide titration

NASA Astrophysics Data System (ADS)

Uehara, H.; Arakaki, T.

2017-12-01

Hypochlorous acid and hypobromous acid (abbreviated as "HypoX acids") are the main ingredients of bleaching and bactericides. The HypoX acids change their chemical forms depending on environmental factors such as pH and various chemical reactions. For example, it has been reported that hypobromite ion in water changes to carcinogenic bromate by photochemical reaction with ultraviolet light. In this study, concentrations of HypoX acids were determined by UV-VIS absorbance measurement utilizing the fact that HypoX acids react with hydrogen peroxide and do not co-exist in the solution. The method for determining the concentration by titration with hydrogen peroxide can be carried out simpler and more efficiently than the DPD method or the current titration method generally used for chlorine concentration measurement. Molar absorptivity between 250 - 500 nm of HypoX acids, including their conjugate base species, was determined by solving theoretical acid-base formula including molar fraction of each chemical species at various pHs. Molar absorptivity of OCl- and OBr- between 250 - 500 nm was determined based on the concentrations obtained from titration with hydrogen peroxide and absorbance at pH > 10, where OCl- and OBr- dominate. Furthermore, the HypoX acids solutions were irradiated with a solar simulator, and the photolysis rate constants were obtained. Based on those values, the half-lives were calculated and the behavior of HypoX acids in the environment was elucidated.

Pulmonary vascular responses during acute and sustained respiratory alkalosis or acidosis in intact newborn piglets.

PubMed

Gordon, J B; Rehorst-Paea, L A; Hoffman, G M; Nelin, L D

1999-12-01

Acute alkalosis-induced pulmonary vasodilation and acidosis-induced pulmonary vasoconstriction have been well described, but responses were generally measured within 5-30 min of changing pH. In contrast, several in vitro studies have found that relatively brief periods of sustained alkalosis can enhance, and sustained acidosis can decrease, vascular reactivity. In this study of intact newborn piglets, effects of acute (20 min) and sustained (60-80 min) alkalosis or acidosis on baseline (35% O2) and hypoxic (12% O2) pulmonary vascular resistance (PVR) were compared with control piglets exposed only to eucapnia. Acute alkalosis decreased hypoxic PVR, but sustained alkalosis failed to attenuate either baseline PVR or the subsequent hypoxic response. Acute acidosis did not significantly increase hypoxic PVR, but sustained acidosis markedly increased both baseline PVR and the subsequent hypoxic response. Baseline PVR was similar in all piglets after resumption of eucapnic ventilation, but the final hypoxic response was greater in piglets previously exposed to alkalosis than in controls. Thus, hypoxic pulmonary vasoconstriction was not attenuated during sustained alkalosis, but was accentuated during sustained acidosis and after the resumption of eucapnia in alkalosis-treated piglets. Although extrapolation of data from normal piglets to infants and children with pulmonary hypertension must be done with caution, this study suggests that sustained alkalosis may be of limited efficacy in treating acute hypoxia-induced pulmonary hypertension and the risks of pulmonary hypertension must be considered when using ventilator strategies resulting in permissive hypercapnic acidosis.

[Adaptation to hypoxia and hyperoxia improves physical endurance: the role of reactive oxygen species and redox-signaling].

PubMed

Sazontova, T G; Glazachev, O S; Bolotova, A V; Dudnik, E N; Striapko, N V; Bedareva, I V; Anchishkina, N A; Arkhipenko, Iu V

2012-06-01

We have conducted theoretical foundation, experimental analysis and a pilot study of a new method of adaptation to hypoxia and hyperoxia in the prevention of hypoxic and stress-induced disorders and improving the body's tolerance to physical stress. It has been shown in the experimental part that a combination of physical exercise with adaptation to hypoxia-hyperoxia significantly increased tolerance to acute physical load (APL) and its active phase. Analysis of lipid peroxidation processes, antioxidant enzymes and HSPs showed that short-term training for physical exercise by itself compensates the stressor, but not the hypoxic component of the APL, the combination of training with adaptation to hypoxia-hyperoxia completely normalizes the stressor and hypoxic components of APL. The pilot study has been performed to evaluate the effectiveness of hypoxic-hyperoxic training course in qualified young athletes with over-training syndrome. After completing the course of hypoxia-hyperoxia adaptation, 14 sessions, accompanied by light mode sports training, the athletes set the normalization of autonomic balance, increased resistance to acute hypoxia in hypoxic test, increased physical performance--increased PWC170, maximal oxygen consumption (VO2max) parameters, their relative values to body mass, diminished shift of rate pressure product in the load. Thus, we confirmed experimental findings that hypoxic-hyperoxic training optimizes hypoxic (increased athletes resistance to proper hypoxia) and stress (myocardium economy in acute physical stress testing) components in systemic adaptation and restoration of athletes' with over-training syndrome.

Prevalence and characteristics of hypoxic hepatitis in the largest single-centre cohort of avian influenza A(H7N9) virus-infected patients with severe liver impairment in the intensive care unit.

PubMed

Zhang, YiMin; Liu, JiMin; Yu, Liang; Zhou, Ning; Ding, Wei; Zheng, ShuFa; Shi, Ding; Li, LanJuan

2016-01-06

Avian influenza A(H7N9) virus (A(H7N9)) emerged in February 2013. Liver impairment of unknown cause is present in 29% of patients with A(H7N9) infection, some of whom experience severe liver injury. Hypoxic hepatitis (HH) is a type of acute severe liver injury characterized by an abrupt, massive increase in serum aminotransferases resulting from anoxic centrilobular necrosis of liver cells. In the intensive care unit (ICU), the prevalence of HH is ∼1%-2%. Here, we report a 1.8% (2/112) incidence of HH in the largest single-centre cohort of ICU patients with A(H7N9) infection. Both HH patients presented with multiple organ failure (MOF) involving respiratory, cardiac, circulatory and renal failure and had a history of chronic heart disease. On admission, severe liver impairment was found. Peak alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values were 937 and 1281 U/L, and 3117 and 3029 U/L, respectively, in the two patients. Unfortunately, both patients died due to deterioration of MOF. A post-mortem biopsy in case 1 confirmed the presence of centrilobular necrosis of the liver, and real-time reverse transcription polymerase chain reaction of A(H7N9)-specific genes was negative, which excluded A(H7N9)-related hepatitis. The incidence of HH in A(H7N9) patients is similar to that in ICU patients with other aetiologies. It seems that patients with A(H7N9) infection and a history of chronic heart disease with a low left ventricular ejection fraction on admission are susceptible to HH, which presents as a marked elevation in ALT at the time of admission.

Ceftriaxone rescues hippocampal neurons from excitotoxicity and enhances memory retrieval in chronic hypobaric hypoxia.

PubMed

Hota, Sunil K; Barhwal, Kalpana; Ray, Koushik; Singh, Shashi B; Ilavazhagan, G

2008-05-01

Exposure to high altitude is known to cause impairment in cognitive functions in sojourners. The molecular events leading to this behavioral manifestation, however, still remain an enigma. The present study aims at exploring the nature of memory impairment occurring on chronic exposure to hypobaric hypoxia and the possible role of glutamate in mediating it. Increased ionotropic receptor stimulation by glutamate under hypobaric hypoxic conditions could lead to calcium mediated excitotoxic cell death resulting in impaired cognitive functions. Since glutamate is cleared from the synapse by the Glial Glutamate Transporter, upregulation of the transporter can be a good strategy in preventing excitotoxic cell death. Considering previous reports on upregulation of the expression of Glial Glutamate Transporter on ceftriaxone administration, the therapeutic potential of ceftriaxone in ameliorating hypobaric hypoxia induced memory impairment was investigated in male Sprague Dawley rats. Exposure to hypobaric hypoxia equivalent to an altitude of 7600 m for 14 days lead to oxidative stress, chromatin condensation and neuronal degeneration in the hippocampus. This was accompanied by delayed memory retrieval as evident from increased latency and pathlength in Morris Water Maze. Administration of ceftriaxone at a dose of 200 mg/kg for 7 days and 14 days during the exposure on the other hand improved the performance of rats in the water maze along with decreased oxidative stress and enhanced neuronal survival when compared to hypoxic group without drug administration. An increased expression of Glial Glutamate Transporter was also observed following drug administration indicating faster clearance of glutamate from the synapse. The present study not only brings to light the effect of longer duration of exposure to hypobaric hypoxia on the memory functions, but also indicates the pivotal role played by glutamate in mediating excitotoxic neuronal degeneration at high altitude. The therapeutic potential of ceftriaxone in providing neuroprotection in excitotoxic conditions by increasing Glial Glutamate Transporter expression and thereby enhancing glutamate uptake from the synapse has also been explored.

Effects of fenoterol on ventilatory response to hypercapnia and hypoxia in patients with chronic obstructive pulmonary disease

PubMed Central

Suzuki, S.; Watanuki, Y.; Yoshiike, Y.; Okubo, T.

1997-01-01

BACKGROUND: It has previously been shown that fenoterol, a beta 2 adrenergic agonist, increases the ventilatory response to hypoxia (HVR) and hypercapnia (HCVR) in normal subjects. The effects of beta 2 adrenergic agonists on chemoreceptors in patients with chronic obstructive pulmonary disease (COPD) remain controversial. This study was designed to examine whether fenoterol increases the HVR and HCVR in patients with COPD. METHODS: The HCVR was tested in 20 patients using a rebreathing method and the HVR was examined using a progressive isocapnic hypoxic method. The HCVR and HVR were assessed by calculating the slopes of plots of occlusion pressure (P0.1) and ventilation (VE) against end tidal carbon dioxide pressure (PETCO2) and arterial oxygen saturation (SaO2), respectively. Spirometric values, lung volumes, and respiratory muscle strength were also measured. The HCVR and HVR were examined after the oral administration of fenoterol (15 mg/day) or placebo for seven days. RESULTS: Fenoterol treatment increased the forced expiratory volume in one second (FEV1) and inspiratory muscle strength. In the HCVR the slope of P0.1 versus PETCO2 was increased by fenoterol from 0.35 (0.23) to 0.43 (0.24) (p < 0.01). Moreover, the P0.1 at PETCO2 of 8 kPa was higher on fenoterol than on placebo (p < 0.05) and the VE was also greater (p < 0.01). In the HVR fenoterol treatment increased the P0.1 at 80% SaO2 from 0.90 (0.72) to 0.97 (0.55) kPa (p < 0.05) while the slopes of the response of P0.1 and VE were not changed. CONCLUSIONS: Fenoterol increases the ventilatory response to hypercapnia in patients with COPD, presumably by stimulation of the central chemoreceptor. The hypoxic ventilatory response is only slightly affected by fenoterol. 


 PMID:9059471

A new perspective on the pathogenesis of chronic renal disease in captive cheetahs (Acinonyx jubatus)

PubMed Central

Prozesky, Leon; Lawrence, John

2018-01-01

The sustainability of captive cheetah populations is limited by high mortality due to chronic renal disease. This necropsy study, conducted on 243 captive cheetahs from one institution, investigated the relationships between focal palatine erosions, gastritis, enterocolitis, glomerulosclerosis, chronic renal infarcts, renal cortical and medullary fibrosis, and renal medullary amyloidosis at death. Associations between the individual renal lesions and death due to chronic renal disease and comparisons of lesion prevalence between captive bred and wild born and between normal and king coated cheetahs were also assessed. All lesions were significantly positively correlated with age at death. Renal medullary fibrosis was the only lesion associated with the likelihood of death being due to chronic renal disease, and cheetahs with this lesion were younger, on average, than cheetahs with other renal lesions. Alimentary tract lesions were not associated with amyloidosis. All lesions, except for palatine erosions, were more common in wild born than in captive bred cheetahs; the former were older at death than the latter. Having a king coat had no clear effect on disease prevalence. These results suggest that age and renal medullary fibrosis are the primary factors influencing the pathogenesis of chronic renal disease in captive cheetahs. Apart from amyloidosis, these findings are analogous to those described in chronic renal disease in domestic cats, which is postulated to result primarily from repetitive hypoxic injury of renal tubules, mediated by age and stress. Cheetahs may be particularly susceptible to acute renal tubular injury due to their propensity for stress and their extended life span in captivity, as well as their adaptation for fecundity (rather than longevity) and adrenaline-mediated high speed prey chases. The presence of chronic renal disease in subadult cheetahs suggests that prevention, identification and mitigation of stress are critical to the successful prevention of chronic renal disease in captive cheetahs. PMID:29513736

A new perspective on the pathogenesis of chronic renal disease in captive cheetahs (Acinonyx jubatus).

PubMed

Mitchell, Emily P; Prozesky, Leon; Lawrence, John

2018-01-01

The sustainability of captive cheetah populations is limited by high mortality due to chronic renal disease. This necropsy study, conducted on 243 captive cheetahs from one institution, investigated the relationships between focal palatine erosions, gastritis, enterocolitis, glomerulosclerosis, chronic renal infarcts, renal cortical and medullary fibrosis, and renal medullary amyloidosis at death. Associations between the individual renal lesions and death due to chronic renal disease and comparisons of lesion prevalence between captive bred and wild born and between normal and king coated cheetahs were also assessed. All lesions were significantly positively correlated with age at death. Renal medullary fibrosis was the only lesion associated with the likelihood of death being due to chronic renal disease, and cheetahs with this lesion were younger, on average, than cheetahs with other renal lesions. Alimentary tract lesions were not associated with amyloidosis. All lesions, except for palatine erosions, were more common in wild born than in captive bred cheetahs; the former were older at death than the latter. Having a king coat had no clear effect on disease prevalence. These results suggest that age and renal medullary fibrosis are the primary factors influencing the pathogenesis of chronic renal disease in captive cheetahs. Apart from amyloidosis, these findings are analogous to those described in chronic renal disease in domestic cats, which is postulated to result primarily from repetitive hypoxic injury of renal tubules, mediated by age and stress. Cheetahs may be particularly susceptible to acute renal tubular injury due to their propensity for stress and their extended life span in captivity, as well as their adaptation for fecundity (rather than longevity) and adrenaline-mediated high speed prey chases. The presence of chronic renal disease in subadult cheetahs suggests that prevention, identification and mitigation of stress are critical to the successful prevention of chronic renal disease in captive cheetahs.

The Ion Channel TRPA1 Is Required for Chronic Itch

PubMed Central

Wilson, Sarah R.; Nelson, Aislyn M.; Batia, Lyn; Morita, Takeshi; Estandian, Daniel; Owens, David M.; Lumpkin, Ellen A.; Bautista, Diana M.

2013-01-01

Chronic itch is a debilitating condition that affects one in 10 people. Little is known about the molecules that mediate chronic itch in primary sensory neurons and skin. We demonstrate that the ion channel TRPA1 is required for chronic itch. Using a mouse model of chronic itch, we show that scratching evoked by impaired skin barrier is abolished in TRPA1-deficient animals. This model recapitulates many of the pathophysiological hallmarks of chronic itch that are observed in prevalent human diseases such as atopic dermatitis and psoriasis, including robust scratching, extensive epidermal hyperplasia, and dramatic changes in gene expression in sensory neurons and skin. Remarkably, TRPA1 is required for both transduction of chronic itch signals to the CNS and for the dramatic skin changes triggered by dry-skin-evoked itch and scratching. These data suggest that TRPA1 regulates both itch transduction and pathophysiological changes in the skin that promote chronic itch. PMID:23719797

Therapeutic Evaluation of Mesenchymal Stem Cells in Chronic Gut Inflammation

DTIC Science & Technology

2015-09-01

activate mouse splenocytes obtained from OT2 transgenic (tg) mice with ovalbumin peptide ( OVA ) and quantify T cell proliferation in vitro. The T...cell receptors (TCR) on CD4+ T cells in OT2 tg mice recognize only OVA presented by the major histocompatibility complex II (MHC II) expressed on...mouse OT2 splenocytes with OVA in the presence of increasing numbers of un-manipulated or irradiated hMSCs, we observe little or no suppression of T

Urea impairs β cell glycolysis and insulin secretion in chronic kidney disease

PubMed Central

Koppe, Laetitia; Nyam, Elsa; Vivot, Kevin; Manning Fox, Jocelyn E.; Dai, Xiao-Qing; Nguyen, Bich N.; Attané, Camille; Moullé, Valentine S.; MacDonald, Patrick E.; Ghislain, Julien

2016-01-01

Disorders of glucose homeostasis are common in chronic kidney disease (CKD) and are associated with increased mortality, but the mechanisms of impaired insulin secretion in this disease remain unclear. Here, we tested the hypothesis that defective insulin secretion in CKD is caused by a direct effect of urea on pancreatic β cells. In a murine model in which CKD is induced by 5/6 nephrectomy (CKD mice), we observed defects in glucose-stimulated insulin secretion in vivo and in isolated islets. Similarly, insulin secretion was impaired in normal mouse and human islets that were cultured with disease-relevant concentrations of urea and in islets from normal mice treated orally with urea for 3 weeks. In CKD mouse islets as well as urea-exposed normal islets, we observed an increase in oxidative stress and protein O-GlcNAcylation. Protein O-GlcNAcylation was also observed in pancreatic sections from CKD patients. Impairment of insulin secretion in both CKD mouse and urea-exposed islets was associated with reduced glucose utilization and activity of phosphofructokinase 1 (PFK-1), which could be reversed by inhibiting O-GlcNAcylation. Inhibition of O-GlcNAcylation also restored insulin secretion in both mouse models. These results suggest that insulin secretory defects associated with CKD arise from elevated circulating levels of urea that increase islet protein O-GlcNAcylation and impair glycolysis. PMID:27525435

Clinics in diagnostic imaging (153). Severe hypoxic ischaemic brain injury.

PubMed Central

Chua, Wynne; Lim, Boon Keat; Lim, Tchoyoson Choie Cheio

2014-01-01

A 58-year-old Indian woman presented with asystole after an episode of haemetemesis, with a patient downtime of 20 mins. After initial resuscitation efforts, computed tomography of the brain, obtained to evaluate neurological injury, demonstrated evidence of severe hypoxic ischaemic brain injury. The imaging features of hypoxic ischaemic brain injury and the potential pitfalls with regard to image interpretation are herein discussed. PMID:25091891

Bemithyl potentiates the antioxidant effect of intermittent hypoxic training.

PubMed

Zarubina, I V; Nurmanbetova, F N; Shabanov, P D

2005-08-01

The rats were adapted to hypoxic hypoxia by intermittent training in a flow pressure chamber for 3 days. The course of bemithyl treatment (25 mg/kg intraperitoneally, 3 days) started immediately after the 1st day of training. Bemithyl potentiated the adaptive metabolic changes in rat brain induced by repeated hypoxic hypoxia, increased the individual resistance to hypoxia, and produced a long-lasting effect.

Short-term treatment with flumazenil restores long-term object memory in a mouse model of Down syndrome.

PubMed

Colas, Damien; Chuluun, Bayarsaikhan; Garner, Craig C; Heller, H Craig

2017-04-01

Down syndrome (DS) is a common genetic cause of intellectual disability yet no pro-cognitive drug therapies are approved for human use. Mechanistic studies in a mouse model of DS (Ts65Dn mice) demonstrate that impaired cognitive function is due to excessive neuronal inhibitory tone. These deficits are normalized by chronic, short-term low doses of GABA A receptor (GABA A R) antagonists in adult animals, but none of the compounds investigated are approved for human use. We explored the therapeutic potential of flumazenil (FLUM), a GABA A R antagonist working at the benzodiazepine binding site that has FDA approval. Long-term memory was assessed by the Novel Object Recognition (NOR) testing in Ts65Dn mice after acute or short-term chronic treatment with FLUM. Short-term, low, chronic dose regimens of FLUM elicit long-lasting (>1week) normalization of cognitive function in both young and aged mice. FLUM at low dosages produces long lasting cognitive improvements and has the potential of fulfilling an unmet therapeutic need in DS. Copyright © 2017. Published by Elsevier Inc.

Animal models of neoplastic development.

PubMed

Pitot, H C

2001-01-01

The basic animal model for neoplastic development used by regulatory agencies is the two-year chronic bioassay developed more than 30 years ago and based on the presumed mechanism of action of a few potential chemical carcinogens. Since that time, a variety of other model carcinogenic systems have been developed, usually involving shorter duration, single organ endpoints, multistage models, and those in genetically-engineered mice. The chronic bioassay is still the "gold standard" of regulatory agencies despite a number of deficiencies, while in this country the use of shorter term assays based on single organ endpoints has not been popular. The multistage model of carcinogenesis in mouse epidermis actually preceded the development of the chronic two-year bioassay, but it was not until multistage models in other organ systems were developed that the usefulness of such systems became apparent. Recently, several genetically-engineered mouse lines involving mutations in proto-oncogenes and tumour suppressor genes have been proposed as additional model systems for use in regulatory decisions. It is likely that a combination of several of these model systems may be most useful in both practical and basic applications of cancer prevention and therapy.

PD-1 immune checkpoint blockade promotes brain leukocyte infiltration and diminishes cyst burden in a mouse model of Toxoplasma infection.

PubMed

Xiao, Jianchun; Li, Ye; Yolken, Robert H; Viscidi, Raphael P

2018-06-15

Tissue cysts, the hallmark of chronic Toxoplasma gondii infection, are predominantly located in the brain making clearance of the parasite difficult. Currently available anti-T. gondii drugs are ineffective on cysts and fail to prevent reactivation of latent toxoplasmosis. We examined whether abrogation of inhibitory signaling pathways that maintain T cells in an exhausted state can be exploited for treating T. gondii tissue cysts. By using a mouse model of chronic toxoplasmosis, we showed immune checkpoint blockade directed against the programmed death-1 (PD-1) pathway results in a significant reduction in brain cyst number (77% lower). We showed leukocyte infiltration (CD3+ T cells, CD8+ T cells, and CD11b + cells) in the leptomeninges, choroid plexus, and subependymal tissue, which are known routes of entry of immune cells into the brain, and in proximal brain parenchyma. Our study provides proof of concept for blockade of immune checkpoint inhibitors as a therapy for chronic toxoplasmosis and potentially for other brain pathogens. Copyright © 2018 Elsevier B.V. All rights reserved.

An operant-based detection method for inferring tinnitus in mice.

PubMed

Zuo, Hongyan; Lei, Debin; Sivaramakrishnan, Shobhana; Howie, Benjamin; Mulvany, Jessica; Bao, Jianxin

2017-11-01

Subjective tinnitus is a hearing disorder in which a person perceives sound when no external sound is present. It can be acute or chronic. Because our current understanding of its pathology is incomplete, no effective cures have yet been established. Mouse models are useful for studying the pathophysiology of tinnitus as well as for developing therapeutic treatments. We have developed a new method for determining acute and chronic tinnitus in mice, called sound-based avoidance detection (SBAD). The SBAD method utilizes one paradigm to detect tinnitus and another paradigm to monitor possible confounding factors, such as motor impairment, loss of motivation, and deficits in learning and memory. The SBAD method has succeeded in monitoring both acute and chronic tinnitus in mice. Its detection ability is further validated by functional studies demonstrating an abnormal increase in neuronal activity in the inferior colliculus of mice that had previously been identified as having tinnitus by the SBAD method. The SBAD method provides a new means by which investigators can detect tinnitus in a single mouse accurately and with more control over potential confounding factors than existing methods. This work establishes a new behavioral method for detecting tinnitus in mice. The detection outcome is consistent with functional validation. One key advantage of mouse models is they provide researchers the opportunity to utilize an extensive array of genetic tools. This new method could lead to a deeper understanding of the molecular pathways underlying tinnitus pathology. Copyright © 2017 Elsevier B.V. All rights reserved.

Gene Profiles in a Smoke-Induced COPD Mouse Lung Model Following Treatment with Mesenchymal Stem Cells.

PubMed

Kim, You-Sun; Kokturk, Nurdan; Kim, Ji-Young; Lee, Sei Won; Lim, Jaeyun; Choi, Soo Jin; Oh, Wonil; Oh, Yeon-Mok

2016-10-01

Mesenchymal stem cells (MSCs) effectively reduce airway inflammation and regenerate the alveolus in cigarette- and elastase-induced chronic obstructive pulmonary disease (COPD) animal models. The effects of stem cells are thought to be paracrine and immune-modulatory because very few stem cells remain in the lung one day after their systemic injection, which has been demonstrated previously. In this report, we analyzed the gene expression profiles to compare mouse lungs with chronic exposure to cigarette smoke with non-exposed lungs. Gene expression profiling was also conducted in a mouse lung tissue with chronic exposure to cigarette smoke following the systemic injection of human cord blood-derived mesenchymal stem cells (hCB-MSCs). Globally, 834 genes were differentially expressed after systemic injection of hCB-MSCs. Seven and 21 genes, respectively, were up-and downregulated on days 1, 4, and 14 after HCB-MSC injection. The Hbb and Hba, genes with oxygen transport and antioxidant functions, were increased on days 1 and 14. A serine protease inhibitor was also increased at a similar time point after injection of hCB-MSCs. Gene Ontology analysis indicated that the levels of genes related to immune responses, metabolic processes, and blood vessel development were altered, indicating host responses after hCB-MSC injection. These gene expression changes suggest that MSCs induce a regeneration mechanism against COPD induced by cigarette smoke. These analyses provide basic data for understanding the regeneration mechanisms promoted by hCB-MSCs in cigarette smoke-induced COPD.

Hypoxic Episodes in Bronchopulmonary Dysplasia

PubMed Central

Martin, Richard J.; Di Fiore, Juliann M.; Walsh, Michele C.

2015-01-01

Hypoxic episodes are troublesome components of bronchopulmonary dysplasia in preterm infants. Immature respiratory control appears to be the major contributor, typically superimposed upon abnormal respiratory function. As a result, relatively short respiratory pauses may precipitate desaturation and accompanying bradycardia. As this population is predisposed to pulmonary hypertension, it is likely that pulmonary vasoconstriction may also play a role in hypoxic episodes. The natural history of intermittent hypoxic episodes has been well characterized in the preterm population at risk for BPD. However, the consequences of these episodes are less clear. Proposed associations of intermittent hypoxia include retinopathy of prematurity, sleep disordered breathing, and neurodevelopmental delay. Future study should address whether these associations are causal relationships. PMID:26593081

A Futile Redox Cycle Involving Neuroglobin Observed at Physiological Temperature.

PubMed

Liu, Anyang; Brittain, Thomas

2015-08-24

Previous studies identifying the potential anti-apoptotic role of neuroglobin raise the question as to how cells might employ neuroglobin to avoid the apoptotic impact of acute hypoxia whilst also avoiding chronic enhancement of tumour formation. We show that under likely physiological conditions neuroglobin can take part in a futile redox cycle. Determination of the rate constants for each of the steps in the cycle allows us to mathematically model the steady state concentration of the active anti-apoptotic ferrous form of neuroglobin under various conditions. Under likely normal physiological conditions neuroglobin is shown to be present in the ferrous state at approximately 30% of its total cellular concentration. Under hypoxic conditions this rapidly rises to approximately 80%. Temporal analysis of this model indicates that the transition from low concentrations to high concentration of ferrous neuroglobin occurs on the seconds time scale. These findings indicate a potential control model for the anti-apoptotic activity of neuroglobin, under likely physiological conditions, whereby, in normoxic conditions, the anti-apoptotic activity of neuroglobin is maintained at a low level, whilst immediately a transition occurs to a hypoxic situation, as might arise during stroke, the anti-apoptotic activity is drastically increased. In this way the cell avoids unwanted increased oncogenic potential under normal conditions, but the rapid activation of neuroglobin provides anti-apoptotic protection in times of acute hypoxia.

Acute fatal posthypoxic leukoencephalopathy following benzodiazepine overdose: a case report and review of the literature.

PubMed

Aljarallah, Salman; Al-Hussain, Fawaz

2015-04-30

Among the rare neurological complications of substances of abuse is the selective cerebral white matter injury (leukoencephalopathy). Of which, the syndrome of delayed post hypoxic encephalopathy (DPHL) that follows an acute drug overdose, in addition to "chasing the dragon" toxicity which results from chronic heroin vapor inhalation remain the most commonly described syndromes of toxic leukoencephalopathy. These syndromes are reported in association with opioid use. There are very few cases in the literature that described leukoencephalopathy following benzodiazepines, especially with an acute and progressive course. In this paper, we present a patient who developed an acute severe fatal leukoencephalopathy following hypoxic coma and systemic shock induced by benzodiazepine overdose. A 19-year-old male was found comatose at home and brought to hospital in a deep coma, shock, hypoxia, and acidosis. Brain magnetic resonant imaging (MRI) revealed a strikingly selective white matter injury early in the course of the disease. The patient remained in a comatose state with no signs of neurologic recovery until he died few weeks later following an increase in the brain edema and herniation. Toxic leukoencephalopathy can occur acutely following an overdose of benzodiazepine and respiratory failure. This is unlike the usual cases of toxic leukoencephalopathy where there is a period of lucidity between the overdose and the development of white matter disease. Unfortunately, this syndrome remains of an unclear pathophysiology and with no successful treatment.

Effects of a Single Bout of Interval Hypoxia on Cardiorespiratory Control in Patients With Type 1 Diabetes

PubMed Central

Duennwald, Tobias; Bernardi, Luciano; Gordin, Daniel; Sandelin, Anna; Syreeni, Anna; Fogarty, Christopher; Kytö, Janne P.; Gatterer, Hannes; Lehto, Markku; Hörkkö, Sohvi; Forsblom, Carol; Burtscher, Martin; Groop, Per-Henrik

2013-01-01

Hypoxemia is common in diabetes, and reflex responses to hypoxia are blunted. These abnormalities could lead to cardiovascular/renal complications. Interval hypoxia (IH) (5–6 short periods of hypoxia each day over 1–3 weeks) was successfully used to improve the adaptation to hypoxia in patients with chronic obstructive pulmonary disease. We tested whether IH over 1 day could initiate a long-lasting response potentially leading to better adaptation to hypoxia. In 15 patients with type 1 diabetes, we measured hypoxic and hypercapnic ventilatory responses (HCVRs), ventilatory recruitment threshold (VRT-CO2), baroreflex sensitivity (BRS), blood pressure, and blood lactate before and after 0, 3, and 6 h of a 1-h single bout of IH. All measurements were repeated on a placebo day (single-blind protocol, randomized sequence). After IH (immediately and after 3 h), hypoxic and HCVR increased, whereas the VRT-CO2 dropped. No such changes were observed on the placebo day. Systolic and diastolic blood pressure increased, whereas blood lactate decreased after IH. Despite exposure to hypoxia, BRS remained unchanged. Repeated exposures to hypoxia over 1 day induced an initial adaptation to hypoxia, with improvement in respiratory reflexes. Prolonging the exposure to IH (>2 weeks) in type 1 diabetic patients will be a matter for further studies. PMID:23733200

Osteoarthritis-like pathologic changes in the knee joint induced by environmental disruption of circadian rhythms is potentiated by a high-fat diet.

PubMed

Kc, Ranjan; Li, Xin; Forsyth, Christopher B; Voigt, Robin M; Summa, Keith C; Vitaterna, Martha Hotz; Tryniszewska, Beata; Keshavarzian, Ali; Turek, Fred W; Meng, Qing-Jun; Im, Hee-Jeong

2015-11-20

A variety of environmental factors contribute to progressive development of osteoarthritis (OA). Environmental factors that upset circadian rhythms have been linked to various diseases. Our recent work establishes chronic environmental circadian disruption - analogous to rotating shiftwork-associated disruption of circadian rhythms in humans - as a novel risk factor for the development of OA. Evidence suggests shift workers are prone to obesity and also show altered eating habits (i.e., increased preference for high-fat containing food). In the present study, we investigated the impact of chronic circadian rhythm disruption in combination with a high-fat diet (HFD) on progression of OA in a mouse model. Our study demonstrates that when mice with chronically circadian rhythms were fed a HFD, there was a significant proteoglycan (PG) loss and fibrillation in knee joint as well as increased activation of the expression of the catabolic mediators involved in cartilage homeostasis. Our results, for the first time, provide the evidence that environmental disruption of circadian rhythms plus HFD potentiate OA-like pathological changes in the mouse joints. Thus, our findings may open new perspectives on the interactions of chronic circadian rhythms disruption with diet in the development of OA and may have potential clinical implications.

Macrophage Depletion Attenuates Extracellular Matrix Deposition and Ductular Reaction in a Mouse Model of Chronic Cholangiopathies

PubMed Central

Syn, Wing-Kin; Lagaisse, Kimberly; van Hul, Noemi; Heindryckx, Femke; Sowa, Jan-Peter; Peeters, Liesbeth; Van Vlierberghe, Hans; Leclercq, Isabelle A.; Canbay, Ali

2016-01-01

Chronic cholangiopathies, such as primary and secondary sclerosing cholangitis, are progressive disease entities, associated with periportal accumulation of inflammatory cells, encompassing monocytes and macrophages, peribiliary extracellular matrix (ECM) deposition and ductular reaction (DR). This study aimed to elucidate the relevance of macrophages in the progression of chronic cholangiopathies through macrophage depletion in a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) mouse model. One group of mice received a single i.p. injection of Clodronate encapsulated liposomes (CLOLipo) at day 7 of a 14 day DDC treatment, while control animals were co-treated with PBSLipo instead. Mice were sacrificed after 7 or respectively 14 days of treatment for immunohistochemical assessment of macrophage recruitment (F4/80), ECM deposition (Sirius Red, Laminin) and DR (CK19). Macrophage depletion during a 14 day DDC treatment resulted in a significant inhibition of ECM deposition. Porto-lobular migration patterns of laminin-rich ECM and ductular structures were significantly attenuated and a progression of DR was effectively inhibited by macrophage depletion. CLOLipo co-treatment resulted in a confined DR to portal regions without amorphous cell clusters. This study suggests that therapeutic options selectively directed towards macrophages might represent a feasible treatment for chronic cholestatic liver diseases. PMID:27618307

Heparanase and macrophage interplay in the onset of liver fibrosis.

PubMed

Secchi, Maria Francesca; Crescenzi, Marika; Masola, Valentina; Russo, Francesco Paolo; Floreani, Annarosa; Onisto, Maurizio

2017-11-02

The heparan sulfate endoglycosidase heparanase (HPSE) is involved in tumor growth, chronic inflammation and fibrosis. Since a role for HPSE in chronic liver disease has not been demonstrated to date, the current study was aimed at investigating the involvement of HPSE in the pathogenesis of chronic liver injury. Herein, we revealed that HPSE expression increased in mouse livers after carbon tetrachloride (CCl 4 )-mediated chronic induction of fibrosis, but with a trend to decline during progression of the disease. In mouse fibrotic liver tissues HPSE immunostaining was restricted in necro-inflammatory areas, co-localizing with F4/80 macrophage marker and TNF-α. TNF-α treatment induced HPSE expression as well as HPSE secretion in U937 macrophages. Moreover, macrophage-secreted HPSE regulated the expression of α-SMA and fibronectin in hepatic stellate LX-2 cells. Finally, HPSE activity increased in the plasma of patients with liver fibrosis but it inversely correlated with liver stiffness. Our results suggest the involvement of HPSE in early phases of reaction to liver damage and inflammatory macrophages as an important source of HPSE. HPSE seems to play a key role in the macrophage-mediated activation of hepatic stellate cells (HSCs), thus suggesting that HPSE targeting could be a new therapeutic option in the treatment of liver fibrosis.

Stress activates pronociceptive endogenous opioid signalling in DRG neurons during chronic colitis.

PubMed

Guerrero-Alba, Raquel; Valdez-Morales, Eduardo E; Jimenez-Vargas, Nestor N; Lopez-Lopez, Cintya; Jaramillo-Polanco, Josue; Okamoto, Takanobu; Nasser, Yasmin; Bunnett, Nigel W; Lomax, Alan E; Vanner, Stephen J

2017-12-01

Psychological stress accompanies chronic inflammatory diseases such as IBD, and stress hormones can exacerbate pain signalling. In contrast, the endogenous opioid system has an important analgesic action during chronic inflammation. This study examined the interaction of these pathways. Mouse nociceptive dorsal root ganglia (DRG) neurons were incubated with supernatants from segments of inflamed colon collected from patients with chronic UC and mice with dextran sodium sulfate (cDSS)-induced chronic colitis. Stress effects were studied by adding stress hormones (epinephrine and corticosterone) to dissociated neurons or by exposing cDSS mice to water avoidance stress. Changes in excitability of colonic DRG nociceptors were measured using patch clamp and Ca 2+ imaging techniques. Supernatants from patients with chronic UC and from colons of mice with chronic colitis caused a naloxone-sensitive inhibition of neuronal excitability and capsaicin-evoked Ca 2+ responses. Stress hormones decreased signalling induced by human and mouse supernatants. This effect resulted from stress hormones signalling directly to DRG neurons and indirectly through signalling to the immune system, leading to decreased opioid levels and increased acute inflammation. The net effect of stress was a change endogenous opioid signalling in DRG neurons from an inhibitory to an excitatory effect. This switch was associated with a change in G protein-coupled receptor excitatory signalling to a pathway sensitive to inhibitors of protein kinase A-protein, phospholipase C-protein and G protein βϒ subunits. Stress hormones block the inhibitory actions of endogenous opioids and can change the effect of opioid signalling in DRG neurons to excitation. Targeting these pathways may prevent heavy opioid use in IBD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Epigallocatechin-3-gallate attenuates acute and chronic psoriatic itch in mice: Involvement of antioxidant, anti-inflammatory effects and suppression of ERK and Akt signaling pathways.

PubMed

Guo, Ran; Zhou, Feng-Ming; Su, Cun-Jin; Liu, Teng-Teng; Zhou, Yan; Fan, Li; Wang, Zhi-Hong; Liu, Xu; Huang, Ya; Liu, Tong; Yang, Jianping; Chen, Li-Hua

2018-02-19

Chronic itch is a distressing symptom of many skin diseases and negatively impacts quality of life. However, there is no medication for most forms of chronic itch, although antihistamines are often used for anti-itch treatment. Epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, exhibits anti-oxidative and anti-inflammatory properties. Our previous studies highlighted a key role of oxidative stress and proinflammatory cytokines in acute and chronic itch. Here, we evaluated the effects of green tea polyphenon 60 and EGCG on acute and chronic itch in mouse models and explored its potential mechanisms. The effects of EGCG were determined by behavioral tests in mouse models of acute and chronic itch, which were induced by compound 48/80, chloroquine (CQ), and 5% imiquimod cream treatment, respectively. We found that systemic or local administration of green tea polyphenon 60 or EGCG significantly alleviated compound 48/80- and chloroquine-induced acute itch in a dose-dependent manner in mice. Incubation of EGCG significantly decreased the accumulation of intracellular reactive oxygen species (ROS) directly induced by compound 48/80 and CQ in cultured ND7-23 cells, a dorsal root ganglia derived cell line. EGCG also attenuated imiquimod-induced chronic psoriatic itch behaviors and skin epidermal hyperplasia in mice. In addition, EGCG inhibited the expression of IL-23 mRNA in skin and TRPV1 mRNA in dorsal root ganglia (DRG). Finally, EGCG remarkably inhibited compound 48/80-induced phosphorylation of extracellular signal-regulated kinase (ERK) and imiquimod-induced p-AKT in the spinal cord of mice, respectively. Collectively, these results indicated EGCG could be a promising strategy for anti-itch therapy. Copyright © 2018. Published by Elsevier Inc.

Impaired gait pattern as a sensitive tool to assess hypoxic brain damage in a novel mouse model of atherosclerotic plaque rupture.

PubMed

Roth, Lynn; Van Dam, Debby; Van der Donckt, Carole; Schrijvers, Dorien M; Lemmens, Katrien; Van Brussel, Ilse; De Deyn, Peter P; Martinet, Wim; De Meyer, Guido R Y

2015-02-01

Apolipoprotein E deficient (ApoE(-/-)) mice with a heterozygous mutation in the fibrillin-1 gene (Fbn1(C1039G+/-)) show spontaneous atherosclerotic plaque ruptures, disturbances in cerebral flow and sudden death when fed a Western-type diet (WD). The present study focused on motor coordination and spatial learning of ApoE(-/-) Fbn1(C1039G+/-) mice on WD for 20 weeks (n=21). ApoE(-/-) mice on WD (n=24) and ApoE(-/-) Fbn1(C1039G+/-) mice on normal diet (ND, n=21) served as controls. Starting from 10 weeks of diet, coordination was assessed every two weeks by the following tests: gait analysis, stationary beam, wire suspension and accelerating rotarod. The Morris water maze test was performed after 13 weeks of diet to study spatial learning. At the end of the experiment (20 weeks of WD), the mice were sacrificed and the brachiocephalic artery and brain were isolated. From 12 weeks onward, gait analysis of ApoE(-/-) Fbn1(C1039G+/-) mice on WD revealed a progressive increase in track width as compared to ApoE(-/-) mice on WD and ApoE(-/-) Fbn1(C1039G+/-) mice on ND (at 20 weeks: 29.8±0.6 mm vs. 25.8±0.4 mm and 26.0±0.5 mm). Moreover, the stationary beam test showed a decrease in motor coordination of ApoE(-/-) Fbn1(C1039G+/-) mice on WD at 18 and 20 weeks. The wire suspension test and accelerating rotarod could not detect signs of motor impairment. Spatial learning was also not affected. Histological analysis of the brachiocephalic artery showed larger and more stenotic plaques in ApoE(-/-) Fbn1(C1039G+/-) mice on WD. Furthermore, the parietal cortex of ApoE(-/-) Fbn1(C1039G+/-) mice on WD showed pyknotic nuclei as a sign of hypoxia and the percentage of pyknosis correlated with track width. In conclusion, gait analysis may be an efficient method for analyzing hypoxic brain damage in the ApoE(-/-) Fbn1(C1039G+/-) mouse model. This test could be of value to assess the effect of potential anti-atherosclerotic therapies in mice. Copyright © 2014 Elsevier Inc. All rights reserved.

Transcriptional Profiling of Hypoxic Neural Stem Cells Identifies Calcineurin-NFATc4 Signaling as a Major Regulator of Neural Stem Cell Biology

PubMed Central

Moreno, Marta; Fernández, Virginia; Monllau, Josep M.; Borrell, Víctor; Lerin, Carles; de la Iglesia, Núria

2015-01-01

Summary Neural stem cells (NSCs) reside in a hypoxic microenvironment within the brain. However, the crucial transcription factors (TFs) that regulate NSC biology under physiologic hypoxia are poorly understood. Here we have performed gene set enrichment analysis (GSEA) of microarray datasets from hypoxic versus normoxic NSCs with the aim of identifying pathways and TFs that are activated under oxygen concentrations mimicking normal brain tissue microenvironment. Integration of TF target (TFT) and pathway enrichment analysis identified the calcium-regulated TF NFATc4 as a major candidate to regulate hypoxic NSC functions. Nfatc4 expression was coordinately upregulated by top hypoxia-activated TFs, while NFATc4 target genes were enriched in hypoxic NSCs. Loss-of-function analyses further revealed that the calcineurin-NFATc4 signaling axis acts as a major regulator of NSC self-renewal and proliferation in vitro and in vivo by promoting the expression of TFs, including Id2, that contribute to the maintenance of the NSC state. PMID:26235896

Targeting hypoxic microenvironment of pancreatic xenografts with the hypoxia-activated prodrug TH-302.

PubMed

Lohse, Ines; Rasowski, Joanna; Cao, Pinjiang; Pintilie, Melania; Do, Trevor; Tsao, Ming-Sound; Hill, Richard P; Hedley, David W

2016-06-07

Previous reports have suggested that the hypoxic microenvironment provides a niche that supports tumor stem cells, and that this might explain clinical observations linking hypoxia to metastasis. To test this, we examined the effects of a hypoxia-activated prodrug, TH-302, on the tumor-initiating cell (TIC) frequency of patient-derived pancreatic xenografts (PDX).The frequencies of TIC, measured by limiting dilution assay, varied widely in 11 PDX models, and were correlated with rapid growth but not with the levels of hypoxia. Treatment with either TH-302 or ionizing radiation (IR), to target hypoxic and well-oxygenated regions, respectively, reduced TIC frequency, and the combination of TH-302 and IR was much more effective in all models tested. The combination was also more effective than TH-302 or IR alone controlling tumor growth, particularly treating the more rapidly-growing/hypoxic models. These findings support the clinical utility of hypoxia targeting in combination with radiotherapy to treat pancreatic cancers, but do not provide strong evidence for a hypoxic stem cell niche.

Reoxygenation in the RIF-1 tumor

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

Dorie, M.J.; Kallman, R.F.

1984-05-01

The proportion of hypoxic cells in the RIF-1 tumor was examined for 13 days following a 15 Gy conditioning dose. The paired survival curve technique indicated that 100% of the surviving cells were hypoxic immediately following this treatment. However, within 1 hour, only about 50% remained hypoxic; this proportion continued to drop to about 10% but did not reach the pretreatment level of 1.1% for the duration of the study.

Acute Hypoxic Stress Affects Migration Machinery of Tissue O2-Adapted Adipose Stromal Cells.

PubMed

Udartseva, Olga O; Lobanova, Margarita V; Andreeva, Elena R; Buravkov, Sergey V; Ogneva, Irina V; Buravkova, Ludmila B

2016-01-01

The ability of mesenchymal stromal (stem) cells (MSCs) to be mobilised from their local depot towards sites of injury and to participate in tissue repair makes these cells promising candidates for cell therapy. Physiological O 2 tension in an MSC niche in vivo is about 4-7%. However, most in vitro studies of MSC functional activity are performed at 20% O 2 . Therefore, this study focused on the effects of short-term hypoxic stress (0.1% O 2 , 24 h) on adipose tissue-derived MSC motility at tissue-related O 2 level. No significant changes in integrin expression were detected after short-term hypoxic stress. However, O 2 deprivation provoked vimentin disassembly and actin polymerisation and increased cell stiffness. In addition, hypoxic stress induced the downregulation of ACTR3, DSTN, MACF1, MID1, MYPT1, NCK1, ROCK1, TIAM1 , and WASF1 expression, the products of which are known to be involved in leading edge formation and cell translocation. These changes were accompanied by the attenuation of targeted and nontargeted migration of MSCs after short-term hypoxic exposure, as demonstrated in scratch and transwell migration assays. These results indicate that acute hypoxic stress can modulate MSC function in their native milieu, preventing their mobilisation from sites of injury.

Acute Hypoxic Stress Affects Migration Machinery of Tissue O2-Adapted Adipose Stromal Cells

PubMed Central

Lobanova, Margarita V.; Andreeva, Elena R.

2016-01-01

The ability of mesenchymal stromal (stem) cells (MSCs) to be mobilised from their local depot towards sites of injury and to participate in tissue repair makes these cells promising candidates for cell therapy. Physiological O2 tension in an MSC niche in vivo is about 4–7%. However, most in vitro studies of MSC functional activity are performed at 20% O2. Therefore, this study focused on the effects of short-term hypoxic stress (0.1% O2, 24 h) on adipose tissue-derived MSC motility at tissue-related O2 level. No significant changes in integrin expression were detected after short-term hypoxic stress. However, O2 deprivation provoked vimentin disassembly and actin polymerisation and increased cell stiffness. In addition, hypoxic stress induced the downregulation of ACTR3, DSTN, MACF1, MID1, MYPT1, NCK1, ROCK1, TIAM1, and WASF1 expression, the products of which are known to be involved in leading edge formation and cell translocation. These changes were accompanied by the attenuation of targeted and nontargeted migration of MSCs after short-term hypoxic exposure, as demonstrated in scratch and transwell migration assays. These results indicate that acute hypoxic stress can modulate MSC function in their native milieu, preventing their mobilisation from sites of injury. PMID:28115943

An HRE-Binding Py-Im Polyamide Impairs Hypoxic Signaling in Tumors.

PubMed

Szablowski, Jerzy O; Raskatov, Jevgenij A; Dervan, Peter B

2016-04-01

Hypoxic gene expression contributes to the pathogenesis of many diseases, including organ fibrosis, age-related macular degeneration, and cancer. Hypoxia-inducible factor-1 (HIF1), a transcription factor central to the hypoxic gene expression, mediates multiple processes including neovascularization, cancer metastasis, and cell survival. Pyrrole-imidazole polyamide 1: has been shown to inhibit HIF1-mediated gene expression in cell culture but its activity in vivo was unknown. This study reports activity of polyamide 1: in subcutaneous tumors capable of mounting a hypoxic response and showing neovascularization. We show that 1: distributes into subcutaneous tumor xenografts and normal tissues, reduces the expression of proangiogenic and prometastatic factors, inhibits the formation of new tumor blood vessels, and suppresses tumor growth. Tumors treated with 1: show no increase in HIF1α and have reduced ability to adapt to the hypoxic conditions, as evidenced by increased apoptosis in HIF1α-positive regions and the increased proximity of necrotic regions to vasculature. Overall, these results show that a molecule designed to block the transcriptional activity of HIF1 has potent antitumor activity in vivo, consistent with partial inhibition of the tumor hypoxic response. Mol Cancer Ther; 15(4); 608-17. ©2015 AACR. ©2015 American Association for Cancer Research.

Hypothermia therapy for newborns with hypoxic ischemic encephalopathy.

PubMed

Silveira, Rita C; Procianoy, Renato S

2015-01-01

Therapeutic hypothermia reduces cerebral injury and improves the neurological outcome secondary to hypoxic ischemic encephalopathy in newborns. It has been indicated for asphyxiated full-term or near-term newborn infants with clinical signs of hypoxic-ischemic encephalopathy (HIE). A search was performed for articles on therapeutic hypothermia in newborns with perinatal asphyxia in PubMed; the authors chose those considered most significant. There are two therapeutic hypothermia methods: selective head cooling and total body cooling. The target body temperature is 34.5 °C for selective head cooling and 33.5 °C for total body cooling. Temperatures lower than 32 °C are less neuroprotective, and temperatures below 30 °C are very dangerous, with severe complications. Therapeutic hypothermia must start within the first 6h after birth, as studies have shown that this represents the therapeutic window for the hypoxic-ischemic event. Therapy must be maintained for 72 h, with very strict control of the newborn's body temperature. It has been shown that therapeutic hypothermia is effective in reducing neurologic impairment, especially in full-term or near-term newborns with moderate hypoxic-ischemic encephalopathy. Therapeutic hypothermia is a neuroprotective technique indicated for newborn infants with perinatal asphyxia and hypoxic-ischemic encephalopathy. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Hypoxia interface behavior of the ctenophore Mnemiopsis leidyi

NASA Astrophysics Data System (ADS)

Gentry, L. A.; Moss, A.

2016-02-01

The ctenophore Mnemiopsis leidyi is most widely known as a destructive invasive species of the Black and Caspian seas. Ctenophores are also found endemically in oceans worldwide, where their low oxygen tolerances allow many of them to use hypoxic zones to escape predation and hunt disabled prey. Ctenophores have also been observed in the wild and laboratory conditions associating with the interface of hypoxic and normoxic waters, allowing them to feed on the organisms found there. In order to test the ability of M. leidyi to find oxygen interfaces, a 10 cm diameter X 60 cm tall cylindrical tank was designed with a sharp oxycline (<1cm) in the middle, stabilized by a 1 ppt salinity difference. The hypoxic water was produced by nitrogen bubbling prior to the experiment. We found that animals introduced to the tank under oxycline conditions increased their time spent at the interface by over nearly five-fold versus those in a fully normoxic or hypoxic water. These preliminary results would indicate that M. leidyi preferentially associates with the interfaces of hypoxic zones. As human effects such as overfishing, nutrient enrichment of coastal waters, and invasive introduction continue to rise, the complex interactions of these animals and hypoxic zones will become increasingly important to planktonic and pelagic ecosystems worldwide.

Neurotransmitters and neuromodulators controlling the hypoxic respiratory response in anaesthetized cats.

PubMed

Richter, D W; Schmidt-Garcon, P; Pierrefiche, O; Bischoff, A M; Lalley, P M

1999-01-15

1. The contributions of neurotransmitters and neuromodulators to the responses of the respiratory network to acute hypoxia were analysed in anaesthetized cats. 2. Samples of extracellular fluid were collected at 1-1.5 min time intervals by microdialysis in the medullary region of ventral respiratory group neurones and analysed for their content of glutamate, gamma-aminobutyric acid (GABA), serotonin and adenosine by high performance liquid chromatography. Phrenic nerve activity was correlated with these measurements. 3. Levels of glutamate and GABA increased transiently during early periods of hypoxia, coinciding with augmented phrenic nerve activity and then fell below control during central apnoea. Serotonin and adenosine increased slowly and steadily with onset of hypoxic depression of phrenic nerve activity. 4. The possibility that serotonin contributes to hypoxic respiratory depression was tested by microinjecting the 5-HT-1A receptor agonist 8-OH-DPAT into the medullary region that is important for rhythmogenesis. Hypoxic activation of respiratory neurones and phrenic nerve activity were suppressed. Microinjections of NAN-190, a 5-HT-1A receptor blocker, enhanced hypoxic augmentation resulting in apneustic prolongation of inspiratory bursts. 5. The results reveal a temporal sequence in the release of neurotransmitters and neuromodulators and suggest a specific role for each of them in the sequential development of hypoxic respiratory disturbances.

Hypoxia induces triglycerides accumulation in prostate cancer cells and extracellular vesicles supporting growth and invasiveness following reoxygenation

PubMed Central

Kumar, Rahul; Dhar, Deepanshi; Agarwal, Chapla; Bergman, Bryan; Graner, Michael; Maroni, Paul; Singh, Rana P.; Agarwal, Rajesh; Deep, Gagan

2015-01-01

Hypoxia is an independent prognostic indicator of poor outcome in several malignancies. However, precise mechanism through which hypoxia promotes disease aggressiveness is still unclear. Here, we report that under hypoxia (1% O2), human prostate cancer (PCA) cells, and extracellular vesicles (EVs) released by these cells, are significantly enriched in triglycerides due to the activation of lipogenesis-related enzymes and signaling molecules. This is likely a survival response to hypoxic stress as accumulated lipids could support growth following reoxygenation. Consistent with this, significantly higher proliferation was observed in hypoxic PCA cells following reoxygenation associated with rapid use of accumulated lipids. Importantly, lipid utilization inhibition by CPT1 inhibitor etomoxir and shRNA-mediated CPT1-knockdown significantly compromised hypoxic PCA cell proliferation following reoxygenation. Furthermore, COX2 inhibitor celecoxib strongly reduced growth and invasiveness following hypoxic PCA cells reoxygenation, and inhibited invasiveness induced by hypoxic PCA EVs. This establishes a role for COX2 enzymatic products in the enhanced PCA growth and invasiveness. Importantly, concentration and loading of EVs secreted by PCA cells were significantly compromised under delipidized serum condition and by lipogenesis inhibitors (fatostatin and silibinin). Overall, present study highlights the biological significance of lipid accumulation in hypoxic PCA cells and its therapeutic relevance in PCA. PMID:26087400

Agglutination of Trypanosoma cruzi in infected cells treated with serum from chronically infected mice.

PubMed

Wendelken, Jennifer L; Rowland, Edwin C

2009-04-01

The protozoan parasite Trypanosoma cruzi is the causative agent of Chagas disease. The chronic stage of infection is characterized by a production of neutralizing antibodies in the vertebrate host. A polyclonal antibody, anti-egressin, has been found to inhibit egress of parasites from the host cell late in the intracellular cycle, after the parasites have transformed from the replicative amastigote into the trypomastigote. It has also been found that BALB/c mouse fibroblasts in the late stages of parasite infection become permeable to molecules as large as antibodies, leading to the possibility that anti-egressin affects the intracellular parasites. This project addresses the fate of the intracellular trypomastigotes that have been inhibited from egressing the host cell. Extended cultures of infected fibroblasts treated with chronic mouse serum reduced parasite egress at all time points measured. Parasites released from infected fibroblasts treated with chronic serum had a reduced ability to infect fibroblasts in culture, yet did not lose infectivity entirely. Absorption of chronic serum with living trypomastigotes removed the anti-egressin effect. The possibility that the target of anti-egressin is a parasite surface component is further indicated by the agglutination of extracellular trypomastigotes by chronic serum. The possibility that cross-linking by antibody occurs intracellularly, thus inhibiting egress, was reinforced by cleaving purified IgG into Fab fragments, which did not inhibit egress when added to infected cultures. From this work, it is proposed that the current, best explanation of the mechanism of egress inhibition by anti-egressin is intracellular agglutination, preventing normal parasite-driven egress.

Asthma progression to airway remodeling and bone marrow eosinophil responses in genetically distinct strains of mice.

PubMed

Hogan, Mary Beth; Piktel, Debra; Hubbs, Ann F; McPherson, Leslie E; Landreth, Kenneth S

2008-12-01

Patient factors that cause long-term airway remodeling are largely unidentified. This suggests that genetic differences may determine which asthmatic patients develop airway remodeling. A murine model with repeated allergen exposure leading to peribronchial fibrosis in complement factor 5 (C5)-deficient A/J mice has been used to study asthma progression. No studies have addressed the systemic effects of allergen sensitization or chronic allergen exposure on bone marrow eosinophilopoiesis in this mouse strain. To investigate bone marrow eosinophil responses during acute sensitization and chronic allergen exposure using genetically distinct mouse strains differing in persistent airway reactivity and remodeling. The C5-sufficient BALB/c and C5-deficient A/J mice were repetitively exposed to intranasal ovalbumin for 12 weeks. Subsequently, the mice were evaluated for airway eosinophilia, mucus-containing goblet cells, and peribronchial fibrosis. Both strains of mice were also acutely sensitized to ovalbumin. Bone marrow eosinophil progenitor cells and mature eosinophils were enumerated. BALB/c and A/J mice have similar bone marrow responses after acute allergen exposure, with elevations in bone marrow eosinophil progenitor cell and eosinophil numbers. After chronic allergen exposure, only C5-deficient A/J mice that developed peribronchial fibrosis exhibited bone marrow eosinophilia. BALB/c mice lacked peribronchial fibrosis and extinguished accelerated eosinophil production after long-term allergen challenge. Chronic airway remodeling after repeated allergen exposure in genetically different mice correlated with differences in long-term bone marrow eosinophilopoiesis. Preventing asthma from progressing to chronic airway remodeling with fibrosis may involve identifying genetically determined influences on bone marrow responses to chronic allergen exposure.

Role of Kv7 channels in responses of the pulmonary circulation to hypoxia.

PubMed

Sedivy, Vojtech; Joshi, Shreena; Ghaly, Youssef; Mizera, Roman; Zaloudikova, Marie; Brennan, Sean; Novotna, Jana; Herget, Jan; Gurney, Alison M

2015-01-01

Hypoxic pulmonary vasoconstriction (HPV) is a beneficial mechanism that diverts blood from hypoxic alveoli to better ventilated areas of the lung, but breathing hypoxic air causes the pulmonary circulation to become hypertensive. Responses to airway hypoxia are associated with depolarization of smooth muscle cells in the pulmonary arteries and reduced activity of K(+) channels. As Kv7 channels have been proposed to play a key role in regulating the smooth muscle membrane potential, we investigated their involvement in the development of HPV and hypoxia-induced pulmonary hypertension. Vascular effects of the selective Kv7 blocker, linopirdine, and Kv7 activator, flupirtine, were investigated in isolated, saline-perfused lungs from rats maintained for 3-5 days in an isobaric hypoxic chamber (FiO2 = 0.1) or room air. Linopirdine increased vascular resistance in lungs from normoxic, but not hypoxic rats. This effect was associated with reduced mRNA expression of the Kv7.4 channel α-subunit in hypoxic arteries, whereas Kv7.1 and Kv7.5 were unaffected. Flupirtine had no effect in normoxic lungs but reduced vascular resistance in hypoxic lungs. Moreover, oral dosing with flupirtine (30 mg/kg/day) prevented short-term in vivo hypoxia from increasing pulmonary vascular resistance and sensitizing the arteries to acute hypoxia. These findings suggest a protective role for Kv7.4 channels in the pulmonary circulation, limiting its reactivity to pressor agents and preventing hypoxia-induced pulmonary hypertension. They also provide further support for the therapeutic potential of Kv7 activators in pulmonary vascular disease. Copyright © 2015 the American Physiological Society.

Hypoxia monitoring activities within the FP7 EU-project HYPOX: diverse approaches to understand a complex phenomenon

NASA Astrophysics Data System (ADS)

Janssen, F.; Waldmann, C.; Boetius, A.

2012-04-01

Hypoxic conditions in aquatic systems and the occurrence of 'dead zones' increase worldwide due to man-made eutrophication and global warming with consequences for biodiversity, ecosystem functions and services such as fisheries, aquaculture and tourism. Monitoring of hypoxia and its consequences has to (1) account for the appropriate temporal and spatial scales, (2) separate anthropogenic from natural drivers and long-term trends from natural variations, (3) assess ecosystem response, (4) use modeling tools for generalization and prediction, and (5) share data and obtained knowledge. In 2009 the EU FP7 project HYPOX (www.hypox.net) started out as a pioneering attempt to improve and integrate hypoxia observation capacities addressing these requirements. Target ecosystems selected for HYPOX cover a broad range of settings (e.g., hydrography, oxygenation status, biological activity, anthropogenic impact) and differ in their sensitivity towards change. Semi-enclosed basins with permanent anoxia (Black Sea, Baltic Sea), are included as well as seasonally or locally hypoxic land-locked systems (fjords, lagoons, lakes) and open ocean systems with high sensitivity to global warming (North Atlantic - Arctic transition). Adopted monitoring approaches involve autonomous, cabled, and shipboard instruments and include static and profiling moorings, benthic observatories, drifters, as well as classical CTD surveys. In order to improve observatory performance, project activities encompass developments of oxygen sensors as well as calibration procedures and technologies to reduce biofouling. Modeling and data assimilation are used to synthesize findings, to obtain an in-depth understanding of hypoxia causes and consequences, and to improve forecasting capacities. For integration of the collected information into a global oxygen observing system, results are disseminated through the HYPOX portal following GEOSS data sharing principles. This presentation will give an overview of the scientific approach of HYPOX and highlight some key results comprising findings from individual ecosystems and indentified general patterns. The driving forces that lead to hypoxia are assessed as well as consequences of oxygen depletion for aquatic life and biogeochemical processes.

Extreme Hypoxic Conditions Induce Selective Molecular Responses and Metabolic Reset in Detached Apple Fruit

PubMed Central

Cukrov, Dubravka; Zermiani, Monica; Brizzolara, Stefano; Cestaro, Alessandro; Licausi, Francesco; Luchinat, Claudio; Santucci, Claudio; Tenori, Leonardo; Van Veen, Hans; Zuccolo, Andrea; Ruperti, Benedetto; Tonutti, Pietro

2016-01-01

The ripening physiology of detached fruit is altered by low oxygen conditions with profound effects on quality parameters. To study hypoxia-related processes and regulatory mechanisms, apple (Malus domestica, cv Granny Smith) fruit, harvested at commercial ripening, were kept at 1°C under normoxic (control) and hypoxic (0.4 and 0.8 kPa oxygen) conditions for up to 60 days. NMR analyses of cortex tissue identified eight metabolites showing significantly different accumulations between samples, with ethanol and alanine displaying the most pronounced difference between hypoxic and normoxic treatments. A rapid up-regulation of alcohol dehydrogenase and pyruvate-related metabolism (lactate dehydrogenase, pyruvate decarboxylase, alanine aminotransferase) gene expression was detected under both hypoxic conditions with a more pronounced effect induced by the lowest (0.4 kPa) oxygen concentration. Both hypoxic conditions negatively affected ACC synthase and ACC oxidase transcript accumulation. Analysis of RNA-seq data of samples collected after 24 days of hypoxic treatment identified more than 1000 genes differentially expressed when comparing 0.4 vs. 0.8 kPa oxygen concentration samples. Genes involved in cell-wall, minor and major CHO, amino acid and secondary metabolisms, fermentation and glycolysis as well as genes involved in transport, defense responses, and oxidation-reduction appeared to be selectively affected by treatments. The lowest oxygen concentration induced a higher expression of transcription factors belonging to AUX/IAA, WRKY, HB, Zinc-finger families, while MADS box family genes were more expressed when apples were kept under 0.8 kPa oxygen. Out of the eight group VII ERF members present in apple genome, two genes showed a rapid up-regulation under hypoxia, and western blot analysis showed that apple MdRAP2.12 proteins were differentially accumulated in normoxic and hypoxic samples, with the highest level reached under 0.4 kPa oxygen. These data suggest that ripe apple tissues finely and specifically modulate sensing and regulatory mechanisms in response to different hypoxic stress conditions. PMID:26909091

C-type natriuretic peptide functions as an innate neuroprotectant in neonatal hypoxic-ischemic brain injury in mouse via natriuretic peptide receptor 2.

PubMed

Ma, Qingyi; Zhang, Lubo

2018-06-01

Neonatal hypoxia-ischemia (HI) is the most common cause of brain injury in neonates, which leads to high neonatal mortality and severe neurological morbidity in later life (Vannucci, 2000; Volpe, 2001). Yet the molecular mechanisms of neuronal death and brain damage induced by neonatal HI remain largely elusive. Herein, using both in vivo and in vitro models, we determine an endogenous neuroprotectant role of c-type natriuretic peptide (CNP) in preserving neuronal survival after HI brain injury in mouse pups. Postnatal day 7 (P7) mouse pups with CNP deficiency (Nppc lbab/lbab ) exhibit increased brain infarct size and worsened long-term locomotor function after neonatal HI compared with wildtype control (Nppc +/+ ). In isolated primary cortical neurons, recombinant CNP dose-dependently protects primary neurons from oxygen-glucose deprivation (OGD) insult. This neuroprotective effect appears to be mediated through its cognate natriuretic peptide receptor 2 (NPR2), in that antagonization of NPR2, but not NPR3, exacerbates neuronal death and counteracts the protective effect of CNP on primary neurons exposed to OGD insult. Immunoblot and confocal microscopy demonstrate the abundant expression of NPR2 in neurons of the neonatal brain and in isolated primary cortical neurons as well. Moreover, similar to CNP deficiency, administration of NPR2 antagonist P19 via intracerebroventricular injection prior to HI results in exacerbated neuronal death and brain injury after HI. Altogether, the present study indicates that CNP and its cognate receptor NPR2 mainly expressed in neurons represent an innate neuroprotective mechanism in neonatal HI brain injury. Copyright © 2018 Elsevier Inc. All rights reserved.

Relationship of oxygen dose to angiogenesis induction in irradiated tissue

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

Marx, R.E.; Ehler, W.J.; Tayapongsak, P.

1990-11-01

This study was accomplished in an irradiated rabbit model to assess the angiogenic properties of normobaric oxygen and hyperbaric oxygen as compared with air-breathing controls. Results indicated that normobaric oxygen had no angiogenic properties above normal revascularization of irradiated tissue than did air-breathing controls (p = 0.89). Hyperbaric oxygen demonstrated an eight- to ninefold increased vascular density over both normobaric oxygen and air-breathing controls (p = 0.001). Irradiated tissue develops a hypovascular-hypocellular-hypoxic tissue that does not revascularize spontaneously. Results failed to demonstrate an angiogenic effect of normobaric oxygen. It is suggested that oxygen in this sense is a drug requiringmore » hyperbaric pressures to generate therapeutic effects on chronically hypovascular irradiated tissue.« less

Myricetin inhibits UVB-induced angiogenesis by regulating PI-3 kinase in vivo

PubMed Central

Jung, Sung Keun; Lee, Ki Won; Byun, Sanguine; Lee, Eun Jung; Kim, Jong-Eun; Bode, Ann M.; Dong, Zigang

2010-01-01

Myricetin is one of the principal phytochemicals in onions, berries and red wine. Previous studies showed that myricetin exhibits potent anticancer and chemopreventive effects. The present study examined the effect of myricetin on ultraviolet (UV) B-induced angiogenesis in an SKH-1 hairless mouse skin tumorigenesis model. Topical treatment with myricetin inhibited repetitive UVB-induced neovascularization in SKH-1 hairless mouse skin. The induction of vascular endothelial growth factor, matrix metalloproteinase (MMP)-9 and MMP-13 expression by chronic UVB irradiation was significantly suppressed by myricetin treatment. Immunohistochemical and western blot analyses revealed that myricetin inhibited UVB-induced hypoxia inducible factor-1α expression in mouse skin. Western blot analysis and kinase assay data revealed that myricetin suppressed UVB-induced phosphatidylinositol-3 (PI-3) kinase activity and subsequently attenuated the UVB-induced phosphorylation of Akt/p70S6K in mouse skin lysates. A pull-down assay revealed the direct binding of PI-3 kinase and myricetin in mouse skin lysates. Our results indicate that myricetin suppresses UVB-induced angiogenesis by regulating PI-3 kinase activity in vivo in mouse skin. PMID:20008033

Development of a Model of Chronic Kidney Disease in the C57BL/6 Mouse with Properties of Progressive Human CKD

PubMed Central

Cruz, Gaile L.; Lu, Chao; Carlisle, Rachel E.; Werner, Kaitlyn E.; Ask, Kjetil; Dickhout, Jeffrey G.

2015-01-01

Chronic kidney disease (CKD) is a major healthcare problem with increasing prevalence in the population. CKD leads to end stage renal disease and increases the risk of cardiovascular disease. As such, it is important to study the mechanisms underlying CKD progression. To this end, an animal model was developed to allow the testing of new treatment strategies or molecular targets for CKD prevention. Many underlying risk factors result in CKD but the disease itself has common features, including renal interstitial fibrosis, tubular epithelial cell loss through apoptosis, glomerular damage, and renal inflammation. Further, CKD shows differences in prevalence between the genders with premenopausal women being relatively resistant to CKD. We sought to develop and characterize an animal model with these common features of human CKD in the C57BL/6 mouse. Mice of this genetic background have been used to produce transgenic strains that are commercially available. Thus, a CKD model in this strain would allow the testing of the effects of numerous genes on the severity or progression of CKD with minimal cost. This paper describes such a mouse model of CKD utilizing angiotensin II and deoxycorticosterone acetate as inducers. PMID:26064882

More than meets the eye: infant presenting with hypoxic ischaemic encephalopathy.

PubMed

Sen, Kuntal; Agarwal, Rajkumar

2018-04-05

We report a newborn infant who presented with poor Apgar scores and umbilical artery acidosis leading to the diagnosis of hypoxic ischaemic encephalopathy. During the course of the infant's hospitalisation, subsequent workup revealed an underlying genetic cause that masqueraded as hypoxic ischaemic encephalopathy. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Unpredictable chronic mild stress differentially impairs social and contextual discrimination learning in two inbred mouse strains

PubMed Central

van Boxelaere, Michiel; Clements, Jason; Callaerts, Patrick; D’Hooge, Rudi

2017-01-01

Alterations in the social and cognitive domain are considered important indicators for increased disability in many stress-related disorders. Similar impairments have been observed in rodents chronically exposed to stress, mimicking potential endophenotypes of stress-related psychopathologies such as major depression disorder (MDD), anxiety, conduct disorder, and posttraumatic stress disorder (PTSD). Data from numerous studies suggest that deficient plasticity mechanisms in hippocampus (HC) and prefrontal cortex (PFC) might underlie these social and cognitive deficits. Specifically, stress-induced deficiencies in neural plasticity have been associated with a hypodopaminergic state and reduced neural plasticity persistence. Here we assessed the effects of unpredictable chronic mild stress (UCMS) on exploratory, social and cognitive behavior of females of two inbred mouse strains (C57BL/6J and DBA/2J) that differ in their dopaminergic profile. Exposure to chronic stress resulted in impaired circadian rhythmicity, sociability and social cognition in both inbred strains, but differentially affected activity patterns and contextual discrimination performance. These stress-induced behavioral impairments were accompanied by reduced expression levels of brain derived neurotrophic factor (BDNF) in the prefrontal cortex. The strain-specific cognitive impairment was coexistent with enhanced plasma corticosterone levels and reduced expression of genes related to dopamine signaling in hippocampus. These results underline the importance of assessing different strains with multiple test batteries to elucidate the neural and genetic basis of social and cognitive impairments related to chronic stress. PMID:29166674

Baicalin promotes hippocampal neurogenesis via SGK1- and FKBP5-mediated glucocorticoid receptor phosphorylation in a neuroendocrine mouse model of anxiety/depression

PubMed Central

Zhang, Kuo; Pan, Xing; Wang, Fang; Ma, Jie; Su, Guangyue; Dong, Yingxu; Yang, Jingyu; Wu, Chunfu

2016-01-01

Antidepressants increase hippocampal neurogenesis by activating the glucocorticoid receptor (GR), but excessive GR activation impairs hippocampal neurogenesis, suggesting that normal GR function is crucial for hippocampal neurogenesis. Baicalin was reported to regulate the expression of GR and facilitate hippocampal neurogenesis, but the underlying molecular mechanisms are still unknown. In this study, we used the chronic corticosterone (CORT)-induced mouse model of anxiety/depression to assess antidepressant-like effects of baicalin and illuminate possible molecular mechanisms by which baicalin affects GR-mediated hippocampal neurogenesis. We found that oral administration of baicalin (40, 80 or 160 mg/kg) for 4 weeks alleviated several chronic CORT-induced anxiety/depression-like behaviors. Baicalin also increased Ki-67- and DCX-positive cells to restore chronic CORT-induced suppression of hippocampal neurogenesis. Moreover, baicalin normalized the chronic CORT-induced decrease in GR protein levels, the increase in GR nuclear translocation and the increase in GR phosphorylation at Ser203 and Ser211. Finally, chronic CORT exposure increased the level of FK506-binding protein 51 (FKBP5) and of phosphorylated serum- and glucocorticoid-inducible kinase 1 (SGK1) at Ser422 and Thr256, whereas baicalin normalized these changes. Together, our findings suggest that baicalin improves anxiety/depression-like behaviors and promotes hippocampal neurogenesis. We propose that baicalin may normalize GR function through SGK1- and FKBP5-mediated GR phosphorylation. PMID:27502757

Microsensor and transcriptomic signatures of oxygen depletion in biofilms associated with chronic wounds: Biofilms and oxygen

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

James, Garth A.; Ge Zhao, Alice; Usui, Marcia

Polymicrobial biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms may impede wound healing. In this study, we used oxygen microsensors to measure oxygen transects through in vitro-cultured biofilms, biofilms formed in vivo in a diabetic (db/db) mouse model, and ex vivo human chronic wound specimens. The results show that oxygen levels within both euthanized and live mouse wounds had steep gradients that reached minima ranging from 19 to 61% oxygenmore » partial pressure, compared to atmospheric oxygen levels. The oxygen gradients in the mouse wounds were similar to those observed for clinical isolates cultured in vitro and for human ex vivo scabs. No oxygen gradients were observed for heat-killed scabs, suggesting that active metabolism by the viable bacteria contributed to the reduced oxygen partial pressure of the wounds. To characterize the metabolic activities of the bacteria in the mouse wounds, we performed transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds using Affymetrix microarrays. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results indicated that the bacteria within the wounds also experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results support the hypothesis that the metabolic activities of bacteria in biofilms act as oxygen sinks in chronic wounds and that the depletion of oxygen contributes to the detrimental impact of biofilms on wound healing.« less

VEGF blockade inhibits angiogenesis and reepithelialization of endometrium.

PubMed

Fan, Xiujun; Krieg, Sacha; Kuo, Calvin J; Wiegand, Stanley J; Rabinovitch, Marlene; Druzin, Maurice L; Brenner, Robert M; Giudice, Linda C; Nayak, Nihar R

2008-10-01

Despite extensive literature on vascular endothelial growth factor (VEGF) expression and regulation by steroid hormones, the lack of clear understanding of the mechanisms of angiogenesis in the endometrium is a major limitation for use of antiangiogenic therapy targeting endometrial vessels. In the current work, we used the rhesus macaque as a primate model and the decidualized mouse uterus as a murine model to examine angiogenesis during endometrial breakdown and regeneration. We found that blockade of VEGF action with VEGF Trap, a potent VEGF blocker, completely inhibited neovascularization during endometrial regeneration in both models but had no marked effect on preexisting or newly formed vessels, suggesting that VEGF is essential for neoangiogenesis but not survival of mature vessels in this vascular bed. Blockade of VEGF also blocked reepithelialization in both the postmenstrual endometrium and the mouse uterus after decidual breakdown, evidence that VEGF has pleiotropic effects in the endometrium. In vitro studies with a scratch wound assay showed that the migration of luminal epithelial cells during repair involved signaling through VEGF receptor 2-neuropilin 1 (VEGFR2-NP1) receptors on endometrial stromal cells. The leading front of tissue growth during endometrial repair was strongly hypoxic, and this hypoxia was the local stimulus for VEGF expression and angiogenesis in this tissue. In summary, we provide novel experimental data indicating that VEGF is essential for endometrial neoangiogenesis during postmenstrual/postpartum repair.

MicroRNA-188 suppresses G1/S transition by targeting multiple cyclin/CDK complexes.

PubMed

Wu, Jiangbin; Lv, Qing; He, Jie; Zhang, Haoxiang; Mei, Xueshuang; Cui, Kai; Huang, Nunu; Xie, Weidong; Xu, Naihan; Zhang, Yaou

2014-10-11

Accelerated cell cycle progression is the common feature of most cancers. MiRNAs can act as oncogenes or tumor suppressors by directly modulating cell cycle machinery. It has been shown that miR-188 is upregulated in UVB-irradiated mouse skin and human nasopharyngeal carcinoma CNE cells under hypoxic stress. However, little is known about the function of miR-188 in cell proliferation and growth control. Overexpression of miR-188 inhibits cell proliferation, tumor colony formation and G1/S cell cycle transition in human nasopharyngeal carcinoma CNE cells. Using bioinformatics approach, we identify a series of genes regulating G1/S transition as putative miR-188 targets. MiR-188 inhibits both mRNA and protein expression of CCND1, CCND3, CCNE1, CCNA2, CDK4 and CDK2, suppresses Rb phosphorylation and downregulates E2F transcriptional activity. The expression level of miR-188 also inversely correlates with the expression of miR-188 targets in human nasopharyngeal carcinoma (NPC) tissues. Moreover, studies in xenograft mouse model reveal that miR-188 is capable of inhibiting tumor initiation and progression by suppressing target genes expression and Rb phosphorylation. This study demonstrates that miR-188 exerts anticancer effects, via downregulation of multiple G1/S related cyclin/CDKs and Rb/E2F signaling pathway.

Oral delivery of prolyl hydroxylase inhibitor: AKB-4924 promotes localized mucosal healing in a mouse model of colitis.

PubMed

Marks, Ellen; Goggins, Bridie J; Cardona, Jocelle; Cole, Siobhan; Minahan, Kyra; Mateer, Sean; Walker, Marjorie M; Shalwitz, Robert; Keely, Simon

2015-02-01

Pharmacological induction of hypoxia-inducible factor (HIF), a global transcriptional regulator of the hypoxic response, by prolyl hydroxylase inhibitors (PHDi) is protective in murine models of colitis, and epithelial cells are critical for the observed therapeutic efficacy. Because systemic HIF activation may lead to potentially negative off-target effects, we hypothesized that targeting epithelial HIF through oral delivery of PHDi would be sufficient to protect against colitis in a mouse model. Using a chemically induced trinitrobenzene sulfonic acid murine model of colitis, we compared the efficacy of oral and intraperitoneal (i.p.) delivery of the PHDi; AKB-4924 in preventing colitis, as measured by endoscopy, histology, barrier integrity, and immune profiling. Furthermore, we measured potential off-target effects, examining HIF and HIF target genes in the heart and kidney, as well as erythropoietin and hematocrit levels. Oral administration of AKB-4924 exhibited mucosal protection comparable i.p. dosing. Oral delivery of PHDi led to reduced colonic epithelial HIF stabilization compared with i.p. delivery, but this was still sufficient to induce transcription of downstream HIF targets. Furthermore, oral delivery of PHDi led to reduced stabilization of HIF and activation of HIF targets in extraintestinal organs. Oral delivery of PHDi therapies to this intestinal mucosa protects against colitis in animal models and represents a potential therapeutic strategy for inflammatory bowel disease, which also precludes unwanted extraintestinal effects.

Clustering of spontaneous recurrent seizures separated by long seizure-free periods: An extended video-EEG monitoring study of a pilocarpine mouse model.

PubMed

Lim, Jung-Ah; Moon, Jangsup; Kim, Tae-Joon; Jun, Jin-Sun; Park, Byeongsu; Byun, Jung-Ick; Sunwoo, Jun-Sang; Park, Kyung-Il; Lee, Soon-Tae; Jung, Keun-Hwa; Jung, Ki-Young; Kim, Manho; Jeon, Daejong; Chu, Kon; Lee, Sang Kun

2018-01-01

Seizure clustering is a common and significant phenomenon in patients with epilepsy. The clustering of spontaneous recurrent seizures (SRSs) in animal models of epilepsy, including mouse pilocarpine models, has been reported. However, most studies have analyzed seizures for a short duration after the induction of status epilepticus (SE). In this study, we investigated the detailed characteristics of seizure clustering in the chronic stage of a mouse pilocarpine-induced epilepsy model for an extended duration by continuous 24/7 video-EEG monitoring. A seizure cluster was defined as the occurrence of one or more seizures per day for at least three consecutive days and at least five seizures during the cluster period. We analyzed the cluster duration, seizure-free period, cluster interval, and numbers of seizures within and outside the seizure clusters. The video-EEG monitoring began 84.5±33.7 days after the induction of SE and continued for 53.7±20.4 days. Every mouse displayed seizure clusters, and 97.0% of the seizures occurred within a cluster period. The seizure clusters were followed by long seizure-free periods of 16.3±6.8 days, showing a cyclic pattern. The SRSs also occurred in a grouped pattern within a day. We demonstrate that almost all seizures occur in clusters with a cyclic pattern in the chronic stage of a mouse pilocarpine-induced epilepsy model. The seizure-free periods between clusters were long. These findings should be considered when performing in vivo studies using this animal model. Furthermore, this model might be appropriate for studying the unrevealed mechanism of ictogenesis.

Pharmacokinetic Properties of Memantine after a Single Intraperitoneal Administration and Multiple Oral Doses in Euploid Mice and in the Ts65Dn Mouse Model of Down's Syndrome.

PubMed

Victorino, Daniella B; Bederman, Ilya R; Costa, Alberto C S

2017-11-01

Memantine is a drug approved for the treatment of moderate-to-severe Alzheimer's disease (AD), and there is ongoing research on the potential expansion of its clinical applicability. Published data on the pharmacokinetics of memantine in the mouse are still incomplete, particularly for chronic administration regimens and mouse models of specific genetic disorders. Down's syndrome (DS) is a genetic disorder known to affect multiple organs and systems, with the potential to alter significantly drug pharmacokinetics. Here, we describe a simple, efficient and sensitive GC/MS-based procedure for the determination of memantine concentrations in murine blood and tissue samples. We analysed pharmacokinetic properties of memantine, particularly its distribution in blood, brain and liver in the Ts65Dn mouse model of DS and euploid F1 hybrid mice after single intraperitoneal administrations of increasing doses of this drug. We also determined steady-state memantine concentrations in plasma, brain and liver after chronic oral administration of this drug in adult male Ts65Dn mice, euploid littermate controls and nursing or pregnant Ts65Dn mice. Our results revalidated the acute dose of memantine used in previously published work, determined the appropriate amount of memantine to be mixed into mouse chow to achieve steady and pharmacologically relevant plasma and tissue levels of this drug and demonstrated that memantine can be transferred from mother to offspring via maternal milk and placenta. Most of these findings are potentially applicable not only to the study of DS but also to other neurodevelopmental and neurodegenerative disorders. © 2017 The Authors. Basic & Clinical Pharmacology & Toxicology published by John Wiley & Sons Ltd on behalf of Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Oxygen as a driving gas for nebulisers: safe or dangerous?

PubMed

Gunawardena, K A; Patel, B; Campbell, I A; MacDonald, J B; Smith, A P

1984-01-28

Changes in blood gas tensions occurring when 100% oxygen or air was used as the driving gas for nebulised salbutamol were studied in 23 patients with severe airways obstruction. The patients fell into three groups: nine had chronic bronchitis and emphysema with carbon dioxide retention, seven had emphysema and chronic bronchitis without carbon dioxide retention, and seven had severe asthma (no carbon dioxide retention). When oxygen was used as the driving gas patients who retained carbon dioxide showed a mean rise of 1.03 kPa (7.7 mm Hg) in their pressure of carbon dioxide (Pco2) after 15 minutes (p less than 0.001) but the Pco2 returned to baseline values within 20 minutes of stopping the nebuliser. The other two groups showed no rise in Pco2 with oxygen. When air was used as the driving gas none of the groups became significantly more hypoxic. Although it is safe to use oxygen as the driving gas for nebulisers in patients with obstructive airways disease with normal Pco2, caution should be exercised in those who already have carbon dioxide retention.

Whole-Genome Sequencing Uncovers the Genetic Basis of Chronic Mountain Sickness in Andean Highlanders

PubMed Central

Zhou, Dan; Udpa, Nitin; Ronen, Roy; Stobdan, Tsering; Liang, Junbin; Appenzeller, Otto; Zhao, Huiwen W.; Yin, Yi; Du, Yuanping; Guo, Lixia; Cao, Rui; Wang, Yu; Jin, Xin; Huang, Chen; Jia, Wenlong; Cao, Dandan; Guo, Guangwu; Gamboa, Jorge L.; Villafuerte, Francisco; Callacondo, David; Xue, Jin; Liu, Siqi; Frazer, Kelly A.; Li, Yingrui; Bafna, Vineet; Haddad, Gabriel G.

2013-01-01

The hypoxic conditions at high altitudes present a challenge for survival, causing pressure for adaptation. Interestingly, many high-altitude denizens (particularly in the Andes) are maladapted, with a condition known as chronic mountain sickness (CMS) or Monge disease. To decode the genetic basis of this disease, we sequenced and compared the whole genomes of 20 Andean subjects (10 with CMS and 10 without). We discovered 11 regions genome-wide with significant differences in haplotype frequencies consistent with selective sweeps. In these regions, two genes (an erythropoiesis regulator, SENP1, and an oncogene, ANP32D) had a higher transcriptional response to hypoxia in individuals with CMS relative to those without. We further found that downregulating the orthologs of these genes in flies dramatically enhanced survival rates under hypoxia, demonstrating that suppression of SENP1 and ANP32D plays an essential role in hypoxia tolerance. Our study provides an unbiased framework to identify and validate the genetic basis of adaptation to high altitudes and identifies potentially targetable mechanisms for CMS treatment. PMID:23954164

Nitric oxide contributes to the augmented vasodilatation during hypoxic exercise

PubMed Central

Casey, Darren P; Madery, Brandon D; Curry, Timothy B; Eisenach, John H; Wilkins, Brad W; Joyner, Michael J

2010-01-01

We tested the hypotheses that (1) nitric oxide (NO) contributes to augmented skeletal muscle vasodilatation during hypoxic exercise and (2) the combined inhibition of NO production and adenosine receptor activation would attenuate the augmented vasodilatation during hypoxic exercise more than NO inhibition alone. In separate protocols subjects performed forearm exercise (10% and 20% of maximum) during normoxia and normocapnic hypoxia (80% arterial O2 saturation). In protocol 1 (n= 12), subjects received intra-arterial administration of saline (control) and the NO synthase inhibitor NG-monomethyl-l-arginine (l-NMMA). In protocol 2 (n= 10), subjects received intra-arterial saline (control) and combined l-NMMA–aminophylline (adenosine receptor antagonist) administration. Forearm vascular conductance (FVC; ml min−1 (100 mmHg)−1) was calculated from forearm blood flow (ml min−1) and blood pressure (mmHg). In protocol 1, the change in FVC (Δ from normoxic baseline) due to hypoxia under resting conditions and during hypoxic exercise was substantially lower with l-NMMA administration compared to saline (control; P < 0.01). In protocol 2, administration of combined l-NMMA–aminophylline reduced the ΔFVC due to hypoxic exercise compared to saline (control; P < 0.01). However, the relative reduction in ΔFVC compared to the respective control (saline) conditions was similar between l-NMMA only (protocol 1) and combined l-NMMA–aminophylline (protocol 2) at 10% (−17.5 ± 3.7 vs.−21.4 ± 5.2%; P= 0.28) and 20% (−13.4 ± 3.5 vs.−18.8 ± 4.5%; P= 0.18) hypoxic exercise. These findings suggest that NO contributes to the augmented vasodilatation observed during hypoxic exercise independent of adenosine. PMID:19948661

Exercise-induced oxidative stress and hypoxic exercise recovery.

PubMed

Ballmann, Christopher; McGinnis, Graham; Peters, Bridget; Slivka, Dustin; Cuddy, John; Hailes, Walter; Dumke, Charles; Ruby, Brent; Quindry, John

2014-04-01

Hypoxia due to altitude diminishes performance and alters exercise oxidative stress responses. While oxidative stress and exercise are well studied, the independent impact of hypoxia on exercise recovery remains unknown. Accordingly, we investigated hypoxic recovery effects on post-exercise oxidative stress. Physically active males (n = 12) performed normoxic cycle ergometer exercise consisting of ten high:low intensity intervals, 20 min at moderate intensity, and 6 h recovery at 975 m (normoxic) or simulated 5,000 m (hypoxic chamber) in a randomized counter-balanced cross-over design. Oxygen saturation was monitored via finger pulse oximetry. Blood plasma obtained pre- (Pre), post- (Post), 2 h post- (2Hr), 4 h post- (4Hr), and 6 h (6Hr) post-exercise was assayed for Ferric Reducing Ability of Plasma (FRAP), Trolox Equivalent Antioxidant Capacity (TEAC), Lipid Hydroperoxides (LOOH), and Protein Carbonyls (PC). Biopsies from the vastus lateralis obtained Pre and 6Hr were analyzed by real-time PCR quantify expression of Heme oxygenase 1 (HMOX1), Superoxide Dismutase 2 (SOD2), and Nuclear factor (euthyroid-derived2)-like factor (NFE2L2). PCs were not altered between trials, but a time effect (13 % Post-2Hr increase, p = 0.044) indicated exercise-induced blood oxidative stress. Plasma LOOH revealed only a time effect (p = 0.041), including a 120 % Post-4Hr increase. TEAC values were elevated in normoxic recovery versus hypoxic recovery. FRAP values were higher 6Hr (p = 0.045) in normoxic versus hypoxic recovery. Exercise elevated gene expression of NFE2L2 (20 % increase, p = 0.001) and SOD2 (42 % increase, p = 0.003), but hypoxic recovery abolished this response. Data indicate that recovery in a hypoxic environment, independent of exercise, may alter exercise adaptations to oxidative stress and metabolism.

Expression of MUC17 Is Regulated by HIF1α-Mediated Hypoxic Responses and Requires a Methylation-Free Hypoxia Responsible Element in Pancreatic Cancer

PubMed Central

Kitamoto, Sho; Yokoyama, Seiya; Higashi, Michiyo; Yamada, Norishige; Matsubara, Shyuichiro; Takao, Sonshin; Batra, Surinder K.; Yonezawa, Suguru

2012-01-01

MUC17 is a type 1 membrane-bound glycoprotein that is mainly expressed in the digestive tract. Recent studies have demonstrated that the aberrant overexpression of MUC17 is correlated with the malignant potential of pancreatic ductal adenocarcinomas (PDACs); however, the exact regulatory mechanism of MUC17 expression has yet to be identified. Here, we provide the first report of the MUC17 regulatory mechanism under hypoxia, an essential feature of the tumor microenvironment and a driving force of cancer progression. Our data revealed that MUC17 was significantly induced by hypoxic stimulation through a hypoxia-inducible factor 1α (HIF1α)-dependent pathway in some pancreatic cancer cells (e.g., AsPC1), whereas other pancreatic cancer cells (e.g., BxPC3) exhibited little response to hypoxia. Interestingly, these low-responsive cells have highly methylated CpG motifs within the hypoxia responsive element (HRE, 5′-RCGTG-3′), a binding site for HIF1α. Thus, we investigated the demethylation effects of CpG at HRE on the hypoxic induction of MUC17. Treatment of low-responsive cells with 5-aza-2′-deoxycytidine followed by additional hypoxic incubation resulted in the restoration of hypoxic MUC17 induction. Furthermore, DNA methylation of HRE in pancreatic tissues from patients with PDACs showed higher hypomethylation status as compared to those from non-cancerous tissues, and hypomethylation was also correlated with MUC17 mRNA expression. Taken together, these findings suggested that the HIF1α-mediated hypoxic signal pathway contributes to MUC17 expression, and DNA methylation of HRE could be a determinant of the hypoxic inducibility of MUC17 in pancreatic cancer cells. PMID:22970168

Selective toxicity of 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide toward hypoxic mammalian cells

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

Rauth, A.M.; Mohindra, J.K.

1981-12-01

The chemotherapeutic agent 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC) is used in the treatment of malignant melanoma where response rates of 15 to 30% have been reported. Some current interest exists in combining DTIC chemotherapy with localized high-dose (800 rads)-per-fraction radiotherapy in the treatment of unresectable metastatic melanoma. The present work investigates the radiosensitizing and chemotherapeutic properties of DTIC in an in vitro system using Chinese hamster ovary or HeLa cells and in vivo, using the KHT transplantable murine tumor. No evidence of a radiosensitizing effect of DTIC was found towards hypoxic or aerobic cells either in vitro or in vivo. In vitro, highmore » drug concentrations (1 mg/ml) were approximately 5 times more effective in killing hypoxic Chinese hamster ovary or HeLa cells than in killing aerobic cells over exposure times of 0 to 12 hr. The degree of toxicity was drug dose and temperature dependent but was not highly dependent on cell number or cell type. In vivo plasma levels of DTIC were measured with high-pressure liquid chromatography after i.p. injection of drug into C3H mice. At the highest drug doses tested, near the 50% lethal dose in mice for DTIC (0.5 mg/g), the drug was toxic to both aerobic and hypoxic tumor cells with some evidence of increased toxicity towards hypoxic cells. The present work suggests that DTIC may be more efficiently activated under hypoxic conditions as compared to aerobic conditions. The increased toxicity of DTIC under hypoxic versus aerobic conditions may prove to be a feature of this drug that can be exploited in its clinical use and in the design of new analogs of DTIC.« less

Microbial mineralization of dichloroethene and vinyl chloride under hypoxic conditions

USGS Publications Warehouse

Bradley, Paul M.; Chapelle, Francis H.

2011-01-01

Mineralization of 14C-radiolabled vinyl chloride ([1,2-14C] VC) and cis-dichloroethene ([1,2-14C] cis-DCE) under hypoxic (initial dissolved oxygen (DO) concentrations about 0.1 mg/L) and nominally anoxic (DO minimum detection limit = 0.01 mg/L) was examined in chloroethene-exposed sediments from two groundwater and two surface water sites. The results show significant VC and dichloroethene (DCE) mineralization under hypoxic conditions. All the sample treatments exhibited pseudo-first-order kinetics for DCE and VC mineralization over an extended range of substrate concentrations. First-order rates for VC mineralization were approximately 1 to 2 orders of magnitude higher in hypoxic groundwater sediment treatments and at least three times higher in hypoxic surface water sediment treatments than in the respective anoxic treatments. For VC, oxygen-linked processes accounted for 65 to 85% of mineralization at DO concentrations below 0.1 mg/L, and 14CO2 was the only degradation product observed in VC treatments under hypoxic conditions. Because the lower detection limit for DO concentrations measured in the field is typically 0.1 to 0.5 mg/L, these results indicate that oxygen-linked VC and DCE biodegradation can be significant under field conditions that appear anoxic. Furthermore, because rates of VC mineralization exceeded rates of DCE mineralization under hypoxic conditions, DCE accumulation without concomitant accumulation of VC may not be evidence of a DCE degradative “stall” in chloroethene plumes. Significantly, mineralization of VC above the level that could reasonably be attributed to residual DO contamination was also observed in several nominally anoxic (DO minimum detection limit = 0.01 mg/L) microcosm treatments.

Downregulation of miR-210 expression inhibits proliferation, induces apoptosis and enhances radiosensitivity in hypoxic human hepatoma cells in vitro

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

Yang, Wei, E-mail: detachedy@yahoo.com.cn; Sun, Ting; Cao, Jianping

2012-05-01

Hypoxia is a common feature of solid tumors and an important contributor to tumor radioresistance. miR-210 is the most consistently and robustly induced microRNA under hypoxia in different types of tumor cells and normal cells. In the present study, to explore the feasibility of miR-210 as an effective therapeutic target, lentiviral-mediated anti-sense miR-210 gene transfer technique was employed to downregulate miR-210 expression in hypoxic human hepatoma SMMC-7721, HepG2 and HuH7 cells, and phenotypic changes of which were analyzed. Hypoxia led to an increased hypoxia inducible factor-1{alpha} (HIF-1{alpha}) and miR-210 expression and cell arrest in the G{sub 0}/G{sub 1} phase inmore » all cell lines. miR-210 downregulation significantly suppressed cell viability, induced cell arrest in the G{sub 0}/G{sub 1} phase, increased apoptotic rate and enhanced radiosensitivity in hypoxic human hepatoma cells. Moreover, apoptosis-inducing factor, mitochondrion-associated, 3 (AIFM3) was identified as a direct target gene of miR-210. AIFM3 downregulation by siRNA attenuated radiation induced apoptosis in miR-210 downregulated hypoxic human hepatoma cells. Taken together, these data suggest that miR-210 might be a potential therapeutic target and specific inhibition of miR-210 expression in combination with radiotherapy might be expected to exert strong anti-tumor effect on hypoxic human hepatoma cells. -- Highlights: Black-Right-Pointing-Pointer miR-210 downregulation radiosensitized hypoxic hepatoma. Black-Right-Pointing-Pointer AIFM3 was identified as a direct target gene of miR-210. Black-Right-Pointing-Pointer miR-210 might be a therapeutic target to hypoxic hepatoma.« less

Hypoxic survival strategies in two fishes: extreme anoxia tolerance in the North European crucian carp and natural hypoxic preconditioning in a coral-reef shark.

PubMed

Nilsson, Göran E; Renshaw, Gillian M C

2004-08-01

Especially in aquatic habitats, hypoxia can be an important evolutionary driving force resulting in both convergent and divergent physiological strategies for hypoxic survival. Examining adaptations to anoxic/hypoxic survival in hypoxia-tolerant animals may offer fresh ideas for the treatment of hypoxia-related diseases. Here, we summarise our present knowledge of two fishes that have evolved to survive hypoxia under very different circumstances. The crucian carp (Carassius carassius) is of particular interest because of its extreme anoxia tolerance. During the long North European winter, it survives for months in completely oxygen-deprived freshwater habitats. The crucian carp also tolerates a few days of anoxia at room temperature and, unlike anoxia-tolerant freshwater turtles, it is still physically active in anoxia. Moreover, the crucian carp does not appear to reduce neuronal ion permeability during anoxia and may primarily rely on more subtle neuromodulatory mechanisms for anoxic metabolic depression. The epaulette shark (Hemiscyllium ocellatum) is a tropical marine vertebrate. It lives on shallow reef platforms that repeatedly become cut off from the ocean during periods of low tides. During nocturnal low tides, the water [O(2)] can fall by 80% due to respiration of the coral and associated organisms. Since the tides become lower and lower over a period of a few days, the hypoxic exposure during subsequent low tides will become progressively longer and more severe. Thus, this shark is under a natural hypoxic preconditioning regimen. Interestingly, hypoxic preconditioning lowers its metabolic rate and its critical P(O(2)). Moreover, repeated anoxia appears to stimulate metabolic depression in an adenosine-dependent way.