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Sutovska H, Babarikova K, Zeman M, Molcan L. Prenatal Hypoxia Affects Foetal Cardiovascular Regulatory Mechanisms in a Sex- and Circadian-Dependent Manner: A Review. Int J Mol Sci 2022; 23:2885. [PMID: 35270026 PMCID: PMC8910900 DOI: 10.3390/ijms23052885] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 02/28/2022] [Accepted: 03/05/2022] [Indexed: 11/17/2022] Open
Abstract
Prenatal hypoxia during the prenatal period can interfere with the developmental trajectory and lead to developing hypertension in adulthood. Prenatal hypoxia is often associated with intrauterine growth restriction that interferes with metabolism and can lead to multilevel changes. Therefore, we analysed the effects of prenatal hypoxia predominantly not associated with intrauterine growth restriction using publications up to September 2021. We focused on: (1) The response of cardiovascular regulatory mechanisms, such as the chemoreflex, adenosine, nitric oxide, and angiotensin II on prenatal hypoxia. (2) The role of the placenta in causing and attenuating the effects of hypoxia. (3) Environmental conditions and the mother's health contribution to the development of prenatal hypoxia. (4) The sex-dependent effects of prenatal hypoxia on cardiovascular regulatory mechanisms and the connection between hypoxia-inducible factors and circadian variability. We identified that the possible relationship between the effects of prenatal hypoxia on the cardiovascular regulatory mechanism may vary depending on circadian variability and phase of the days. In summary, even short-term prenatal hypoxia significantly affects cardiovascular regulatory mechanisms and programs hypertension in adulthood, while prenatal programming effects are not only dependent on the critical period, and sensitivity can change within circadian oscillations.
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Affiliation(s)
| | | | - Michal Zeman
- Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovakia; (H.S.); (K.B.); (L.M.)
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Morrison JL, Botting KJ, Darby JRT, David AL, Dyson RM, Gatford KL, Gray C, Herrera EA, Hirst JJ, Kim B, Kind KL, Krause BJ, Matthews SG, Palliser HK, Regnault TRH, Richardson BS, Sasaki A, Thompson LP, Berry MJ. Guinea pig models for translation of the developmental origins of health and disease hypothesis into the clinic. J Physiol 2018; 596:5535-5569. [PMID: 29633280 PMCID: PMC6265540 DOI: 10.1113/jp274948] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/19/2018] [Indexed: 12/12/2022] Open
Abstract
Over 30 years ago Professor David Barker first proposed the theory that events in early life could explain an individual's risk of non-communicable disease in later life: the developmental origins of health and disease (DOHaD) hypothesis. During the 1990s the validity of the DOHaD hypothesis was extensively tested in a number of human populations and the mechanisms underpinning it characterised in a range of experimental animal models. Over the past decade, researchers have sought to use this mechanistic understanding of DOHaD to develop therapeutic interventions during pregnancy and early life to improve adult health. A variety of animal models have been used to develop and evaluate interventions, each with strengths and limitations. It is becoming apparent that effective translational research requires that the animal paradigm selected mirrors the tempo of human fetal growth and development as closely as possible so that the effect of a perinatal insult and/or therapeutic intervention can be fully assessed. The guinea pig is one such animal model that over the past two decades has demonstrated itself to be a very useful platform for these important reproductive studies. This review highlights similarities in the in utero development between humans and guinea pigs, the strengths and limitations of the guinea pig as an experimental model of DOHaD and the guinea pig's potential to enhance clinical therapeutic innovation to improve human health.
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Affiliation(s)
- Janna L. Morrison
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, Sansom Institute for Health ResearchUniversity of South AustraliaAdelaideSouth AustraliaAustralia
| | - Kimberley J. Botting
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUK
| | - Jack R. T. Darby
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, Sansom Institute for Health ResearchUniversity of South AustraliaAdelaideSouth AustraliaAustralia
| | - Anna L. David
- Research Department of Maternal Fetal Medicine, Institute for Women's HealthUniversity College LondonLondonUK
| | - Rebecca M. Dyson
- Department of Paediatrics & Child Health and Centre for Translational PhysiologyUniversity of OtagoWellingtonNew Zealand
| | - Kathryn L. Gatford
- Robinson Research Institute and Adelaide Medical SchoolUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Clint Gray
- Department of Paediatrics & Child Health and Centre for Translational PhysiologyUniversity of OtagoWellingtonNew Zealand
| | - Emilio A. Herrera
- Pathophysiology Program, Biomedical Sciences Institute (ICBM), Faculty of MedicineUniversity of ChileSantiagoChile
| | - Jonathan J. Hirst
- Mothers and Babies Research Centre, Hunter Medical Research Institute, School of Biomedical Sciences and PharmacyUniversity of NewcastleCallaghanNew South WalesAustralia
| | - Bona Kim
- Department of PhysiologyUniversity of TorontoTorontoOntarioCanada
| | - Karen L. Kind
- School of Animal and Veterinary SciencesUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Bernardo J. Krause
- Division of Paediatrics, Faculty of MedicinePontificia Universidad Católica de ChileSantiagoChile
| | | | - Hannah K. Palliser
- Mothers and Babies Research Centre, Hunter Medical Research Institute, School of Biomedical Sciences and PharmacyUniversity of NewcastleCallaghanNew South WalesAustralia
| | - Timothy R. H. Regnault
- Departments of Obstetrics and Gynaecology, Physiology and PharmacologyWestern University, and Children's Health Research Institute and Lawson Health Research InstituteLondonOntarioCanada
| | - Bryan S. Richardson
- Departments of Obstetrics and Gynaecology, Physiology and PharmacologyWestern University, and Children's Health Research Institute and Lawson Health Research InstituteLondonOntarioCanada
| | - Aya Sasaki
- Department of PhysiologyUniversity of TorontoTorontoOntarioCanada
| | - Loren P. Thompson
- Department of Obstetrics, Gynecology, and Reproductive SciencesUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Mary J. Berry
- Department of Paediatrics & Child Health and Centre for Translational PhysiologyUniversity of OtagoWellingtonNew Zealand
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Dong Y, Thompson LP. Differential Expression of Endothelial Nitric Oxide Synthase in Coronary and Cardiac Tissue in Hypoxic Fetal Guinea Pig Hearts. ACTA ACUST UNITED AC 2016; 13:483-90. [PMID: 16979353 DOI: 10.1016/j.jsgi.2006.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Indexed: 11/23/2022]
Abstract
OBJECTIVE The purpose of the present study was to quantify the effect of chronic hypoxia on endothelial nitric oxide synthase (eNOS) gene and protein expression of fetal coronary artery segments and cardiac tissue of fetal guinea pig hearts. METHODS Time-mated pregnant guinea pigs (term = 65 days) were housed in room air (NMX, n = 6) or in a hypoxic chamber containing 10.5% O2 for 14 days (HPX14, n = 6). At near term (60 days gestation), fetuses were excised from anesthetized animals via hysterotomy and hearts were removed and weighed. Both coronary artery segments and cardiac ventricle were excised from the same hearts, frozen, and stored at -80 C until ready for study. eNOS mRNA was quantified using real-time polymerase chain reaction (PCR) based on SYBR Green I labeling (BioRad Laboratories, Hercules, CA) using eNOS primers obtained from GeneBank normalized to 18S. eNOS proteins were quantified by Western immunoblotting using eNOS antibody (1:200) and normalized to normoxic controls. eNOS cell-specific localization in the fetal guinea pig heart was performed by double immunofluorescence staining. RESULTS Both coronary artery endothelial cells (EC) and cardiomyocytes (CM) but not vascular smooth muscle cells of normoxic hearts exhibited positive immunostaining of eNOS protein. Chronic hypoxia significantly (P < .05) increased both eNOS mRNA and protein levels of coronary artery segments (by 210.6% and 51.4%, respectively) but decreased (P < .05) mRNA and protein of cardiac tissue (by 50.0% and 40.6%, respectively) in the same hearts. CONCLUSIONS Chronic fetal hypoxia, after 14 days, induces sustained changes in eNOS gene and eNOS protein expression that differ between coronary and cardiac tissue in the fetal guinea pig heart. This study suggests that while the functional roles of altered eNOS expression in hypoxic fetal hearts remain unclear, the site at which eNOS expression is altered may be important in the adaptive response of the fetal heart to hypoxia.
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Affiliation(s)
- Yafeng Dong
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Thompson LP, Aguan K, Zhou H. Chronic Hypoxia Inhibits Contraction of Fetal Arteries by Increased Endothelium-Derived Nitric Oxide and Prostaglandin Synthesis. ACTA ACUST UNITED AC 2016; 11:511-20. [PMID: 15582495 DOI: 10.1016/j.jsgi.2004.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Chronic hypoxia causes redistribution of fetal cardiac output by mechanisms poorly understood. We tested the hypothesis that chronic hypoxia alters vascular reactivity of arteries from near-term fetal guinea pigs. METHODS Pregnant guinea pigs (50 days, term = 65 days) were exposed to either normoxia (room air) or hypoxia (12% O2) for 14 days. Carotid artery ring segments from anesthetized fetuses were mounted onto myographs for measurement of force. Contractile responses to cumulative addition of prostaglandin F2alpha (PGF2alpha, 10(-9) M to 10(-5) M), U46619, a thromboxane mimetic (10(-12) M to 12(-6) M), and KCl (10 to 120 mM) were measured in the presence and absence of INDO (INDO, 10(-5) M) alone and INDO plus nitro-L-arginine (LNA, 10(-4) M), or INDO plus N6-iminoethyl-L-lysine (LNIL, 5 x 10(-5) M, a selective iNOS inhibitor), and measured in endothelium-intact and denuded arteries. Nitric oxide synthase (NOS) activity was measured in isolated arteries by 14C-L-arginine to 14C-L-citrulline conversion. RESULTS Hypoxia decreased contractile responses to both PGF2alpha and U46619 under control conditions. Maximal contraction to both agonists was increased in hypoxemic arteries after INDO alone and INDO + LNA compared to normoxic controls. Endothelium-denudation abolished the differences between the groups. KCl contraction was unaffected by hypoxia. LNIL potentiated maximal PGF(2alpha) contraction but was similar between groups. Hypoxia increased (P < .05) total and Ca(2+)-dependent NOS activities by 1.7- and 2.1-fold, respectively, but had no effect on Ca(2+)-independent activity. CONCLUSION Chronic hypoxia alters vascular reactivity of fetal carotid arteries by increasing the contribution of both vasodilator prostaglandins and nitric oxide and suggests that changes in local vascular mechanisms may be altered by chronic hypoxia.
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Affiliation(s)
- Loren P Thompson
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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Wang WT, Lee P, Dong Y, Yeh HW, Kim J, Weiner CP, Brooks WM, Choi IY. In Vivo Neurochemical Characterization of Developing Guinea Pigs and the Effect of Chronic Fetal Hypoxia. Neurochem Res 2016; 41:1831-43. [PMID: 27233245 DOI: 10.1007/s11064-016-1924-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 02/01/2023]
Abstract
The guinea pig is a frequently used animal model for human pregnancy complications, such as oxygen deprivation or hypoxia, which result in altered brain development. To investigate the impact of in utero chronic hypoxia on brain development, pregnant guinea pigs underwent either normoxic or hypoxic conditions at about 70 % of 65-day term gestation. After delivery, neurochemical profiles consisting of 19 metabolites and macromolecules were obtained from the neonatal cortex, hippocampus, and striatum from birth to 12 weeks postpartum using in vivo (1)H MR spectroscopy at 9.4 T. The effects of chronic fetal hypoxia on the neurochemical profiles were particularly significant at birth. However, the overall developmental trends of neurochemical concentration changes were similar between normoxic and hypoxic animals. Alterations of neurochemicals including N-acetylaspartate (NAA), phosphorylethanolamine, creatine, phosphocreatine, and myo-inositol indicate neuronal loss, delayed myelination, and altered brain energetics due to chronic fetal hypoxia. These observed neurochemical alterations in the developing brain may provide insights into hypoxia-induced brain pathology, neurodevelopmental compromise, and potential neuroprotective measures.
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Affiliation(s)
- Wen-Tung Wang
- Hoglund Brain Imaging Center, University of Kansas Medical Center, 3901 Rainbow Boulevard, MSN 1052, Kansas City, KS, 66160, USA
| | - Phil Lee
- Hoglund Brain Imaging Center, University of Kansas Medical Center, 3901 Rainbow Boulevard, MSN 1052, Kansas City, KS, 66160, USA
- The Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Yafeng Dong
- The Department of Obstetrics and Gynecology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Hung-Wen Yeh
- The Department of Biostatistics, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Jieun Kim
- Hoglund Brain Imaging Center, University of Kansas Medical Center, 3901 Rainbow Boulevard, MSN 1052, Kansas City, KS, 66160, USA
| | - Carl P Weiner
- The Department of Obstetrics and Gynecology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - William M Brooks
- Hoglund Brain Imaging Center, University of Kansas Medical Center, 3901 Rainbow Boulevard, MSN 1052, Kansas City, KS, 66160, USA
- The Department of Neurology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - In-Young Choi
- Hoglund Brain Imaging Center, University of Kansas Medical Center, 3901 Rainbow Boulevard, MSN 1052, Kansas City, KS, 66160, USA.
- The Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
- The Department of Neurology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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Du Z, Zan T, Huang X, Sheng L, Li H, Li H, Li Q. DFO enhances the targeting of CD34-positive cells and improves neovascularization. Cell Transplant 2014; 24:2353-66. [PMID: 25506687 DOI: 10.3727/096368914x685753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Desferrioxamine (DFO), an iron chelator, mimicked hypoxia by inhibiting HIF-1α degradation and upregulated angiogenic factors. In this experiment, we elucidated the effect of DFO on CD34-positive cell migration and neovascularization. CD34-positive cells were cultured in media with DFO or an inhibitor and subjected to in vitro tubule formation and the expression of factors. Nude mice were randomly divided into five groups of 12: control, CD34, CD34-DFO, CD34-DFO-AMD (AMD3100, CXCR4 inhibitor), and CD34-DFO-LY (LY294002, the PI3K inhibitor) groups. Limb perfusion and in vivo imaging was evaluated by laser speckle imaging (LSI) and bioluminescence imaging (BLI). Capillary density was examined 14 days after surgery, and the relevant mechanism was also explored. In vitro, DFO significantly increased the tube formation and expression of angiogenic factors in CD34-positive cells, which were blocked by the PI3K inhibitor, LY294002. DFO enhanced blood flow, the function of the ischemic hindlimb, and the levels of VEGF. Further, p-eNOS and p-Akt increased in response to the ischemia. BLI showed that DFO increased the number of CD34-positive cells targeted to the ischemic sites. Immunohistofluorescence revealed that the capillary density in the ischemic hindlimb was significantly higher in the DFO treatment group compared with the other groups. However, all of these effects were diminished by LY294002. DFO treatment enhanced CD34-positive cell targeting and improved neovascularization via the PI3K/Akt signal transduction pathway in an ischemic hindlimb.
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Affiliation(s)
- Zijing Du
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, P.R. China
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Kim J, Choi IY, Dong Y, Wang WT, Brooks WM, Weiner CP, Lee P. Chronic fetal hypoxia affects axonal maturation in guinea pigs during development: A longitudinal diffusion tensor imaging and T2 mapping study. J Magn Reson Imaging 2014; 42:658-65. [PMID: 25504885 DOI: 10.1002/jmri.24825] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/01/2014] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To investigate the impact of chronic hypoxia on neonatal brains, and follow developmental alterations and adaptations noninvasively in a guinea pig model. Chronic hypoxemia is the prime cause of fetal brain injury and long-term sequelae such as neurodevelopmental compromise, seizures, and cerebral palsy. MATERIALS AND METHODS Thirty guinea pigs underwent either normoxic and hypoxemic conditions during the critical stage of brain development (0.7 gestation) and studied prenatally (n = 16) or perinatally (n = 14). Fourteen newborns (7 hypoxia and 7 normoxia group) were scanned longitudinally to characterize physiological and morphological alterations, and axonal myelination and injury using in vivo diffusion tensor imaging (DTI), T2 mapping, and T2 -weighted magnetic resonance imaging (MRI). Sixteen fetuses (8 hypoxia and 8 normoxia) were studied ex vivo to assess hypoxia-induced neuronal injury/loss using Nissl staining and quantitative reverse transcriptase polymerase chain reaction methods. RESULTS Developmental brains in the hypoxia group showed lower fractional anisotropy in the corpus callosum (-12%, P = 0.02) and lower T2 values in the hippocampus (-16%, P = 0.003) compared with the normoxia group with no differences in the cortex (P > 0.07), indicating vulnerability of the hippocampus and cerebral white matter during early development. Fetal guinea pig brains with chronic hypoxia demonstrated an over 10-fold increase in expression levels of hypoxia index genes such as erythropoietin and HIF-1α, and an over 40% reduction in neuronal density, confirming prenatal brain damage. CONCLUSION In vivo MRI measurement, such as DTI and T2 mapping, provides quantitative parameters to characterize neurodevelopmental abnormalities and to monitor the impact of prenatal insult on the postnatal brain maturation of guinea pigs.
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Affiliation(s)
- Jieun Kim
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - In-Young Choi
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, USA.,Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA.,The Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Yafeng Dong
- Department of Obstetrics and Gynecology, University of Kansas Medical Center, Kansas City, Kansas, USA.,Center for the Developmental Origins of Adult Health and Disease, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Wen-Tung Wang
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - William M Brooks
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, USA.,Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Carl P Weiner
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA.,Department of Obstetrics and Gynecology, University of Kansas Medical Center, Kansas City, Kansas, USA.,Center for the Developmental Origins of Adult Health and Disease, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Phil Lee
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, Kansas, USA.,Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
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Abstract
It is now recognized that the quality of the fetal environment during early development is important in programming cardiovascular health and disease in later life. Fetal hypoxia is one of the most common consequences of complicated pregnancies worldwide. However, in contrast to the extensive research effort on pregnancy affected by maternal nutrition or maternal stress, the contribution of pregnancy affected by fetal chronic hypoxia to developmental programming is only recently becoming delineated and established. This review discusses the increasing body of evidence supporting the programming of cardiac susceptibility to ischaemia and reperfusion (I/R) injury, of endothelial dysfunction in peripheral resistance circulations, and of indices of the metabolic syndrome in adult offspring of hypoxic pregnancy. An additional focus of the review is the identification of plausible mechanisms and the implementation of maternal and early life interventions to protect against adverse programming.
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Wang B, Yan B, Song D, Ye X, Liu SF. Chronic intermittent hypoxia down-regulates endothelial nitric oxide synthase expression by an NF-κB-dependent mechanism. Sleep Med 2012; 14:165-71. [PMID: 23266106 DOI: 10.1016/j.sleep.2012.10.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 10/03/2012] [Accepted: 10/28/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Patients with obstructive sleep apnea have an impaired endothelium-dependent vasodilator response. The mechanisms underlying this impairment remain unclear. We tested the hypothesis that chronic intermittent hypoxia (CIH) impairs endothelium-dependent vasodilatation by NF-κB-mediated down-regulation of endothelial nitric oxide synthase (eNOS) expression. METHODS Wild type (WT) mice and mice deficient in NF-κB p50 or TNF-α gene were exposed to sham or CIH. Aortic NF-κB activity and aortic expression of TNF-α were determined. Aortic and mesenteric artery levels of eNOS expression were examined and their correlation to endothelium-dependent vasodilator response in vitro and vasodepressor response in vivo were analyzed. RESULTS WT mice exposed to CIH for five to eight weeks showed significantly reduced eNOS protein expression in aortas and mesenteric arteries, associated with significantly blunted vasodilator and vasodepressor responses to acetylcholine, but not to sodium nitroprusside. CIH activated NF-κB, which preceded TNF-α up-regulation and eNOS down-regulation. NF-κB p50 gene deletion blocked NF-κB activation, inhibited TNF-α expression, prevented eNOS down-regulation and reversed the impaired endothelium-dependent vasodepressor response induced by CIH. TNF-α knockout prevented CIH-induced eNOS down-regulation and restored the endothelium-dependent vasodepressor response. CONCLUSIONS CIH exposure impairs endothelium-dependent vasodilator mechanism by stimulating NF-κB-mediated TNF-α generation, which in turn, down-regulates eNOS expression, resulting in an impaired endothelium-dependent vasodilatation.
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Affiliation(s)
- Baoshan Wang
- Department of Otolaryngology and Head and Neck Surgery, The First Hospital of Hebei Medical University, Shijiazhuang, China.
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Chronic fetal hypoxia produces selective brain injury associated with altered nitric oxide synthases. Am J Obstet Gynecol 2011; 204:254.e16-28. [PMID: 21272843 DOI: 10.1016/j.ajog.2010.11.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/18/2010] [Accepted: 11/09/2010] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The purpose of this study was to investigate the impact of chronic hypoxia on the nitric oxide synthase isoenzymes in specific brain structures. STUDY DESIGN Time-mated pregnant guinea pigs were exposed to 10.5% molecular oxygen for 14 days (animals with chronic fetal hypoxia; HPX) or room air (control animals; NMX); L-N6-(1-iminoethyl)-lysine (L-NIL; an inducible nitric oxide synthase inhibitor, 1 mg/kg/d) was administered to HPX group for 14 days (L-NIL + HPX). Fetal brains were harvested at term. Multilabeled immunofluorescence was used to generate a brain injury map. Laser capture microdissection and quantitative polymerase chain reaction were applied; cell injury markers, apoptosis activation, neuron loss, total nitric oxide, and the levels of individual nitric oxide synthase isoenzymes were quantified. RESULTS Chronic hypoxia causes selective fetal brain injury rather than global. Injury is associated with differentially affected nitric oxide synthases in both neurons and glial cells, with inducible macrophage-type nitric oxide synthase up-regulated at all injury sites. L-NIL attenuated the injury, despite continued hypoxia. CONCLUSION These studies demonstrate that chronic hypoxia selectively injures the fetal brain in part by the differential regulation of nitric oxide synthase isoenzymes in an anatomic- and cell-specific manner.
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Guo R, Hou W, Dong Y, Yu Z, Stites J, Weiner CP. Brain injury caused by chronic fetal hypoxemia is mediated by inflammatory cascade activation. Reprod Sci 2010; 17:540-8. [PMID: 20360591 DOI: 10.1177/1933719110364061] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The prevalence of cerebral palsy (CP) shows little temporal or geographic variation and is associated with preterm birth, maternal/fetal infection/inflammation, and fetal growth restriction (IUGR), a potential surrogate for chronic fetal hypoxemia (CHX). We previously demonstrated CHX causes a fetal inflammatory response syndrome (FIRS). Herein, we test the hypothesis that CHX may cause fetal brain injury by upregulating inflammatory cytokine cascades, culminating in apoptosis pathway activation. Time-mated guinea pigs were housed in 12% or 10.5% O(2) for the last 21% of gestation. Chronic fetal hypoxemia increased the lactate/pyruvate and decreased the glutathione (GSH)/oxidized glutathione (GSSH) ratios, confirming a shift to a prooxidant state. The end result was a >30% decrease in hippocampal neuron density. Based on a microarray spotted with 113 cytokines and receptors, 22 genes were upregulated by CHX in proportion to the degree of hypoxia; the findings were confirmed by quantitative polymerase chain reaction (PCR). Thus, CHX triggers fetal brain inflammation inversely proportional to its severity characterized by increased apoptosis and neuronal loss. We suggest CHX fetal brain injury is not directly caused by oxygen deprivation but rather is an adaptive response that becomes maladaptive.
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Affiliation(s)
- Rong Guo
- Department of Pathophysiology, Xian Jiaotong University School of Medicine, Xian, Shannxi, PR China
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Thompson L, Dong Y, Evans L. Chronic hypoxia increases inducible NOS-derived nitric oxide in fetal guinea pig hearts. Pediatr Res 2009; 65:188-92. [PMID: 19047955 PMCID: PMC6314287 DOI: 10.1203/pdr.0b013e31818d6ad0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Intrauterine hypoxia impacts fetal growth and organ function. Inducible nitric oxide synthase (iNOS) and neuronal NOS (nNOS) expression was measured to assess the response of fetal hearts to hypoxic (HPX) stress. Pregnant guinea pigs were housed in a hypoxic chamber (10.5% O2 for 14 d, n = 17) or room air [normoxic (NMX), n = 17]. Hearts of anesthetized near-term fetuses were removed. mRNA [hypoxia-inducible factor, (HIF)-1alpha, 1beta, 2alpha, 3alpha, iNOS, and nNOS] and protein levels (HIF-1alpha, iNOS, and nNOS) of fetal cardiac left ventricles were quantified by real time polymerase chain reaction (PCR) and Western analysis, respectively. Cardiac nitrite/nitrate levels were measured in the presence/absence of L-N6-(1-iminoethyl)-lysine (L-NIL), an iNOS inhibitor, administered to pregnant sows. Hypoxia significantly increased fetal cardiac HIF-1alpha and -2alpha mRNA, HIF-1alpha protein but not HIF-3alpha or -1beta mRNA levels. Hypoxia increased both iNOS mRNA (by 5x) and protein (by 23%) levels but had no effect on nNOS levels. Nitrite/nitrate levels were increased in HPX hearts by 2.5x and decreased with L-NIL by 67 +/- 14%. Thus, up-regulation of iNOS-derived nitric oxide (NO) generation is an important mechanism by which fetal hearts respond to chronic hypoxic stress.
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Affiliation(s)
- Loren Thompson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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Hauton D, Ousley V. Prenatal hypoxia induces increased cardiac contractility on a background of decreased capillary density. BMC Cardiovasc Disord 2009; 9:1. [PMID: 19126206 PMCID: PMC2627821 DOI: 10.1186/1471-2261-9-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 01/06/2009] [Indexed: 11/15/2022] Open
Abstract
Background Chronic hypoxia in utero (CHU) is one of the most common insults to fetal development and may be associated with poor cardiac recovery from ischaemia-reperfusion injury, yet the effects on normal cardiac mechanical performance are poorly understood. Methods Pregnant female wistar rats were exposed to hypoxia (12% oxygen, balance nitrogen) for days 10–20 of pregnancy. Pups were born into normal room air and weaned normally. At 10 weeks of age, hearts were excised under anaesthesia and underwent retrograde 'Langendorff' perfusion. Mechanical performance was measured at constant filling pressure (100 cm H2O) with intraventricular balloon. Left ventricular free wall was dissected away and capillary density estimated following alkaline phosphatase staining. Expression of SERCA2a and Nitric Oxide Synthases (NOS) proteins were estimated by immunoblotting. Results CHU significantly increased body mass (P < 0.001) compared with age-matched control rats but was without effect on relative cardiac mass. For incremental increases in left ventricular balloon volume, diastolic pressure was preserved. However, systolic pressure was significantly greater following CHU for balloon volume = 50 μl (P < 0.01) and up to 200 μl (P < 0.05). For higher balloon volumes systolic pressure was not significantly different from control. Developed pressures were correspondingly increased relative to controls for balloon volumes up to 250 μl (P < 0.05). Left ventricular free wall capillary density was significantly decreased in both epicardium (18%; P < 0.05) and endocardium (11%; P < 0.05) despite preserved coronary flow. Western blot analysis revealed no change to the expression of SERCA2a or nNOS but immuno-detectable eNOS protein was significantly decreased (P < 0.001) in cardiac tissue following chronic hypoxia in utero. Conclusion These data offer potential mechanisms for poor recovery following ischaemia, including decreased coronary flow reserve and impaired angiogenesis with subsequent detrimental effects of post-natal cardiac performance.
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Affiliation(s)
- David Hauton
- Department of Physiology, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK.
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Ostergaard L, Stankevicius E, Andersen MR, Eskildsen-Helmond Y, Ledet T, Mulvany MJ, Simonsen U. Diminished NO release in chronic hypoxic human endothelial cells. Am J Physiol Heart Circ Physiol 2007; 293:H2894-903. [PMID: 17720765 DOI: 10.1152/ajpheart.01230.2006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The present study addressed whether chronic hypoxia is associated with reduced nitric oxide (NO) release due to decreased activation of endothelial NO synthase (eNOS). Primary cultures of endothelial cells from human umbilical veins (HUVECs) were used and exposed to different oxygen levels for 24 h, after which NO release, intracellular calcium, and eNOS activity and phosphorylation were measured after 24 h. Direct measurements using a NO microsensor showed that in contrast to 1-h exposure to 5% and 1% oxygen (acute hypoxia), histamine-evoked (10 μM) NO release from endothelial cells exposed to 5% and 1% oxygen for 24 h (chronic hypoxia) was reduced by, respectively, 58% and 40%. Furthermore, chronic hypoxia also lowered the amount and activity of eNOS enzyme. The decrease in activity could be accounted for by reduced intracellular calcium and altered eNOS phosphorylation. eNOS Ser1177 and eNOS Thr495 phosphorylations were reduced and increased, respectively, consistent with lowered enzyme activity. Akt kinase, which can phosphorylate eNOS Ser1177, was also decreased by hypoxia, regarding both total protein content and the phosphorylated (active) form. Moreover, the protein content of β- actin, which is known to influence the activity of eNOS, was almost halved by hypoxia, further supporting the fall in eNOS activity. In conclusion, chronic hypoxia in HUVECs reduces histamine-induced NO release as well as eNOS expression and activity. The decreased activity is most likely due to changed eNOS phosphorylation, which is supported by decreases in Akt expression and phosphorylation. By reducing NO, chronic hypoxia may accentuate endothelial dysfunction in cardiovascular disease.
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Thompson LP, Dong Y. Chronic hypoxia decreases endothelial nitric oxide synthase protein expression in fetal guinea pig hearts. ACTA ACUST UNITED AC 2006; 12:388-95. [PMID: 15982907 DOI: 10.1016/j.jsgi.2005.04.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES The underlying cellular mechanisms mediating hypoxia-induced adaptations in the fetus are poorly understood. We tested the hypothesis that hypoxia up-regulates endothelial nitric oxide synthase (NOS3, type III) protein expression in fetal hearts similar to that observed in adult hearts as a cardioprotective adaptation. This study investigates the effect of chronic hypoxia on NOS3 protein expression in hearts and carotid arteries of fetal guinea pigs exposed to normoxia or intrauterine hypoxia. METHODS Time-mated pregnant guinea pigs (term = 65 days) were housed in either normoxic room air (NMX) or exposed to 12% O(2) (hypoxia; HPX) for 14 or 28 days of duration. At near term ( approximately 60 days of gestation), pregnant mothers were anesthetized and fetal guinea pig hearts and carotid arteries were excised from NMX and HPX animals and frozen until ready for study. In addition, hearts were also excised from anesthetized adult nonpregnant female guinea pigs exposed to either NMX or HPX for 14 days. NOS3 protein was extracted from all tissues and quantified using Western blot analysis. Fetal heart samples were also prepared for localization of NOS3 protein using immunohistochemistry. RESULTS Chronic hypoxia increased both maternal and fetal hematocrit after 28 days of duration. HPX decreased NOS3 protein levels in fetal guinea pig hearts by 29% after 28 days compared to NMX controls. In contrast, HPX increased both NOS3 protein levels in adult hearts by 62% and fetal carotid arteries by fourfold after 14 days of exposure compared to their respective NMX controls. Positive immunostaining of NOS3 protein of fetal hearts was localized in both cardiomyocytes and endothelial cells. CONCLUSION Contrary to our hypothesis, the hypoxia-induced decrease in fetal guinea pig heart NOS3 protein contrasts to the protein levels measured in either adult hearts or fetal carotid arteries. These results suggest that the NOS protein expression is altered differently by hypoxia in fetal and adult hearts and in a peripheral fetal artery exposed to the same level of hypoxia. Thus, the functional role of NO in the fetal heart during hypoxia may differ from that of the adult.
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Affiliation(s)
- Loren P Thompson
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore 21201, USA.
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Abstract
The intrauterine environment plays a powerful role in determining the life-long risk of cardiovascular disease. A number of stressors are well known to affect the development of the cardiovascular system in utero including over/under maternal nutrition, excess glucocorticoid and chronic hypoxia. Chronic fetal anaemia in sheep is a complex stressor that alters cardiac loading conditions, causes hypoxic stress and stimulates large changes in flow to specific tissues, including large increases in resting coronary blood flow and conductance. Decreased viscosity can account for approximately half of the increased flow. It appears that immature hearts are 'plastic' in that increases in coronary conductance with fetal anaemia persist into adulthood even if the anaemia is corrected before birth. These large changes in conductance are possible only through extensive remodelling of the coronary tree. Adult hearts that were once anaemic in utero are more resistant to hypoxic stress as adults but it is not known whether such an adaptation would be deleterious in later life. These studies indicate the need for investigation into the basic mechanisms of coronary tree remodelling in the immature myocardium. New information on these mechanisms is likely to lead to better prevention of and therapies for adult-onset coronary disease.
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Affiliation(s)
- L Davis
- Department of Obstetrics and Gynecology, Oregon Health Sciences University, Portland, OR 97201-3098, USA.
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17
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Chen JX, Meyrick B. Hypoxia increases Hsp90 binding to eNOS via PI3K-Akt in porcine coronary artery endothelium. J Transl Med 2004; 84:182-90. [PMID: 14661033 DOI: 10.1038/labinvest.3700027] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
This study examines the molecular mechanisms by which hypoxia regulates phosphorylated endothelial nitric oxide synthase (eNOS) activity and NO production in porcine coronary artery endothelial cells (PCAEC). Exposure to hypoxia (pO(2)=10 mmHg) for periods up to 3 h resulted in a time-dependent increase in eNOS protein expression and an early (15 min) and sustained increase in eNOS phosphorylation at Ser-1177. Exposure to hypoxia for 30 min led to a doubling in eNOS activity (control=6.2+/-4.4 vs hypoxia=14.1+/-5.0 fmol cGMP/microg protein, P<0.05) and NO release (control=5.9+/-0.8 vs hypoxia=11.8+/-1.2 nM/microg protein, P<0.05). Hypoxia also led to a significant increase in Akt phosphorylation and upregulation of Hsp90 binding to eNOS. Pretreatment of cells with either 1 microg/ml geldanamycin (a specific inhibitor of Hsp90) or 500 nM wortmannin (a specific PI3 kinase inhibitor) suppressed hypoxia-stimulated Akt and eNOS phosphorylation and significantly attenuated hypoxia-stimulated Hsp90 binding to eNOS. Both eNOS activity and NO production were inhibited by geldanamycin and wortmannin. Although hypoxia led to early activation of p42/44 mitogen-activated protein kinases (MAPK), inhibition of their pathway by PD98059 did not suppress hypoxia-stimulated eNOS phosphorylation and eNOS activity. These data demonstrate that hypoxia leads to increased eNOS phosphorylation via stimulated Hsp90 binding to eNOS and activation of the PI3-Akt pathway. We conclude that a coordinated interaction between Hsp90 and PI3-Akt may be an important mechanism by which eNOS activity and NO production is upregulated in hypoxic heart.
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Affiliation(s)
- Jian-xiong Chen
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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18
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Hohimer AR, Mysliwiec M, Lee K, Davis LE, Pantely GA. Perinatal hypoxia causes ventricular enlargement associated with increased atrial natriuretic peptide (ANP) mRNA levels in newborn mice. High Alt Med Biol 2003; 4:241-54. [PMID: 12855055 DOI: 10.1089/152702903322022839] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We sought to examine both the short-term and residual effects of perinatal hypoxia on ventricular mass and function of mice. We postulated that the magnitude of the ventricular hypertrophy would be determined by the timing of the exposure, be linked to augmented atrial natriuretic peptide (ANP) expression, and would persist to young adulthood. Furthermore, mice deficient in the ANP receptor type A (ANPRA) would have even greater hypertrophy. Newborns were placed in a 12% oxygen (O(2)) chamber either shortly after birth or at 8 days of age. Controls were raised in room air. After 8 or 16 days, pups were terminated and the right ventricle (RV) and left ventricle including the septum (LVS) were excised and weighed and total RNA was extracted. Hypoxia caused a reduction in body weight (BW) with an increase in right ventricle (RV) weight, rendering an increased RV to BW ratio and increased LVS/BW, albeit less. Hypertrophy was most pronounced in pups exposed to hypoxia in the first days of extrauterine life. A rapid postnatal decline in both RV and LVS ANP mRNA levels was observed in control animals, while the hypoxia elevated ANP mRNA. In mice missing the ANPRA, both ventricles were more massive than in wild type and hypoxia further augmented RV/BW and LVS/BW. In normal adult animals returned to room air after 16 days of hypoxia, RV but not LVS hypertrophy persisted in both sexes; there was an interaction between gender and the perinatal hypoxic stress on LVS dimension and perhaps on contractility. Thus perinatal hypoxia may "program" the adult mouse heart and vasculature.
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Affiliation(s)
- A Roger Hohimer
- Departments of Obstetrics and Gynecology and Medicine and the Oregon Heart Research Center, Oregon Health & Science University, Portland OR, USA.
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Abstract
This review examines the effect of high altitude and/or chronic hypoxia on cardiac mechanisms that influence perfusion of the fetal heart (e.g., tissue metabolism, coronary vessel growth, and coronary blood flow and vessel responsiveness). In response to intrauterine hypoxia, the fetal heart may either reduce its energy demand or increase its substrate and oxygen delivery as a means of sustaining cardiac function. Cardiac glycolysis predominates as a metabolic pathway of ATP synthesis in the fetal heart under both normoxic and hypoxic conditions. During prolonged oxygen insufficiency, normal cardiac function is sustained by anaerobic glycolysis relying primarily on high levels of stored glycogen in the heart. Chronic hypoxia increases coronary vessel growth and myocardial vascularization in fetal hearts, although the response may depend on the presence of ventricular hypertrophy. Recent studies demonstrate that high altitude hypoxia increases both resting fetal coronary flow and coronary flow reserve as an adaptive response toward increasing oxygen delivery. Hypoxia may also directly effect local vascular smooth muscle mechanisms, resulting in altered coronary artery reactivity to circulating vasoactive substances and contributing to enhanced perfusion. Further study is needed to understand the relative importance of each of these cardiac adaptations in contributing to fetal survival. It is likely that differences in fetal coronary responses to intrauterine hypoxia are highly dependent on the gestational age and relative maturity of the animal species.
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Affiliation(s)
- Loren P Thompson
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
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Earley S, Walker BR. Increased nitric oxide production following chronic hypoxia contributes to attenuated systemic vasoconstriction. Am J Physiol Heart Circ Physiol 2003; 284:H1655-61. [PMID: 12511430 DOI: 10.1152/ajpheart.00964.2002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Attenuated vasoconstrictor reactivity following chronic hypoxia (CH) is associated with endothelium-dependent vascular smooth muscle (VSM) cell hyperpolarization and diminished intracellular [Ca(2+)]. We tested the hypothesis that increased production of nitric oxide (NO) after CH contributes to blunted vasoconstrictor responsiveness. We found that basal NO production of mesenteric arteries from CH rats (barometric pressure = 380 Torr; 48 h) was greater than that of controls (barometric pressure = 630 Torr). In addition, studies employing pressurized mesenteric arteries (100-200 microM ID) abluminally loaded with the Ca(2+) indicator fura 2-AM demonstrated that although NO synthase (NOS) inhibition normalized agonist-induced vasoconstrictor responses between groups, VSM cell [Ca(2+)] in vessels from CH rats remained diminished compared with controls. To determine whether elevated NO production following CH results from increased NOS protein levels, we performed Western blots for NOS isoforms by using mesenteric arteries from control and CH rats. Endothelial NOS levels did not differ between groups, and other NOS isoforms were not detected in these samples. Selective endothelial loading of fura 2-AM was employed to test the hypothesis that elevated endothelial cell [Ca(2+)] following CH accounts for enhanced NOS activity. These experiments demonstrated greater endothelial cell [Ca(2+)] in mesenteric arteries isolated from CH rats compared with controls. We conclude that enhanced production of NO resulting from elevated endothelial cell [Ca(2+)] contributes to attenuated reactivity following CH by decreasing VSM cell Ca(2+) sensitivity.
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Affiliation(s)
- Scott Earley
- Vascular Physiology Group, Department of Cell Biology & Physiology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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21
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Granger JP. Maternal and fetal adaptations during pregnancy: lessons in regulatory and integrative physiology. Am J Physiol Regul Integr Comp Physiol 2002; 283:R1289-92. [PMID: 12429557 DOI: 10.1152/ajpregu.00562.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi, Jackson, Mississippi 39216, USA.
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Adamy C, Oliviero P, Eddahibi S, Rappaport L, Samuel JL, Teiger E, Chassagne C. Cardiac modulations of ANG II receptor expression in rats with hypoxic pulmonary hypertension. Am J Physiol Heart Circ Physiol 2002; 283:H733-40. [PMID: 12124222 DOI: 10.1152/ajpheart.01088.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Right ventricular myocardial hypertrophy during hypoxic pulmonary hypertension is associated with local renin-angiotensin system activation. The expression of angiotensin II type 1 (AT(1)) and type 2 (AT(2)) receptors in this setting has never been investigated. We have therefore examined the chronic hypoxia pattern of AT(1) and AT(2) expression in the right and left cardiac ventricles, using in situ binding and RT-PCR assays. Hypoxia produced right, but not left, ventricular hypertrophy after 7, 14, and 21 days, respectively. Hypoxia for 2 days was associated in each ventricle with a simultaneous and transient increase (P < 0.05) in AT(1) binding and AT(1) mRNA levels in the absence of any significant change in AT(2) expression level. Only after 14 days of hypoxia, AT(2) binding increased (P < 0.05) in the two ventricles, concomitantly with a right ventricular decrease (P < 0.05) in AT(2) mRNA. Along these data, AT(1) and AT(2) binding remained unchanged in both the left and hypertrophied right ventricles from rats treated with monocrotaline for 30 days. These results indicate that chronic hypoxia induces modulations of AT(1) and AT(2) receptors in both cardiac ventricles probably through direct and indirect mechanisms, respectively, which modulations may participate in myogenic (at the level of smooth or striated myocytes) rather than in the growth response of the heart to hypoxia.
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MESH Headings
- Animals
- Heart Ventricles
- Hypertension, Pulmonary/chemically induced
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/metabolism
- Hypertrophy, Right Ventricular/etiology
- Hypertrophy, Right Ventricular/pathology
- Hypoxia/complications
- Ligands
- Male
- Monocrotaline
- Myocardium/metabolism
- Myocardium/pathology
- Organ Size
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptor, Angiotensin, Type 1
- Receptor, Angiotensin, Type 2
- Receptors, Angiotensin/genetics
- Receptors, Angiotensin/metabolism
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Affiliation(s)
- Christophe Adamy
- Institut National de la Santé et de la Recherche Médicale (INSERM) U127/572, Institut Fédératif de Recherche Circulation Paris VII, Hôpital Lariboisière, Université Denis Diderot, 41 boulevard de la Chapelle, 75475 Paris cedex 10, France
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Corno AF, Milano G, Samaja M, Tozzi P, von Segesser LK. Chronic hypoxia: a model for cyanotic congenital heart defects. J Thorac Cardiovasc Surg 2002; 124:105-12. [PMID: 12091815 DOI: 10.1067/mtc.2002.121302] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The postoperative course of cyanotic children is generally more complicated than that of acyanotic children. A possible reason is reoxygenation injury at the beginning of cardiopulmonary bypass. In this study we tested the hypothesis that reoxygenation of chronically hypoxic hearts is worse than that of normoxic hearts. METHODS Two groups of rats (n = 9 each) were exposed to either room air (fraction of inspired oxygen, 0.21%) or chronic hypoxia (fraction of inspired oxygen, 0.10%) for 2 weeks. Hearts were then isolated and perfused for 30 minutes with hypoxic buffer (oxygen saturation, 10%), followed by 30 minutes of reoxygenation (oxygen saturation, 100%). RESULTS In hypoxic rats hematocrit values, hemoglobin concentrations, and red cells were higher (69% +/- 6% vs 40% +/- 6%, 219 +/- 14 vs 124 +/- 12 g/L, and 10.30 +/- 0.6 vs 6.32 +/- 0.5/microL/1000, respectively; P <.0001); the amount of ingested food was less (22.3 +/- 4.8 vs 30.7 +/- 3.9 g/d, P <.001), as was the amount of ingested water (21.0 +/- 3.1 vs 50.4 +/- 14.6 mL/d, P <.0001); and body weight was lower (182 +/- 14.2 vs 351 +/- 40.1 g, P <.0001), as was heart weight (1107 +/- 119 vs 1312 +/- 128 mg, P <.005). The heart weight/body weight ratio was higher (6.10 +/- 0.8 vs 3.74 +/- 0.1 mg/g, P <.0001). Systolic and diastolic functions, not different during the hypoxic baseline period, were more impaired in hypoxic than in normoxic hearts after the reoxygenation, whereas coronary resistance remained lower. During the hypoxic perfusion, the venous partial pressure of oxygen remained low in both groups, whereas during reoxygenation, partial pressure of oxygen was higher in hypoxic hearts, with a lower (P <.01) oxygen uptake. During hypoxic baseline adenosine triphosphate turnover, lactate production and lactate turnover were lower in hypoxic hearts (P <.005, P <.0001, and P <.0001, respectively). CONCLUSIONS Body and blood values are severely affected by chronic hypoxia, and the cardiac effects of uncontrolled reoxygenation after chronic hypoxia are more severe than after acute hypoxia.
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Affiliation(s)
- Antonio F Corno
- Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
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Affiliation(s)
- Holger Scholz
- Johannes-Müller-Institut für Physiologie, Medizinische Fakultät Charité, Humboldt-Universität Berlin, 10117 Berlin, Germany.
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Affiliation(s)
- Heimo Ehmke
- Institut für Physiologie, Universität Hamburg, D-20246 Hamburg, Germany.
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