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Liu Y, Luo Q, Su Z, Xing J, Wu J, Xiang L, Huang Y, Pan H, Wu X, Zhang X, Li J, Yan F, Zhang H. Suppression of Myocardial Hypoxia-Inducible Factor-1α Compromises Metabolic Adaptation and Impairs Cardiac Function in Patients With Cyanotic Congenital Heart Disease During Puberty. Circulation 2021; 143:2254-2272. [PMID: 33663226 DOI: 10.1161/circulationaha.120.051937] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Cyanotic congenital heart disease (CCHD) is a complex pathophysiological condition involving systemic chronic hypoxia (CH). Some patients with CCHD are unoperated for various reasons and remain chronically hypoxic throughout their lives, which heightens the risk of heart failure as they age. Hypoxia activates cellular metabolic adaptation to balance energy demands by accumulating hypoxia-inducible factor 1-α (HIF-1α). This study aims to determine the effect of CH on cardiac metabolism and function in patients with CCHD and its association with age. The role of HIF-1α in this process was investigated, and potential therapeutic targets were explored. METHODS Patients with CCHD (n=25) were evaluated for cardiac metabolism and function with positron emission tomography/computed tomography and magnetic resonance imaging. Heart tissue samples were subjected to metabolomic and protein analyses. CH rodent models were generated to enable continuous observation of changes in cardiac metabolism and function. The role of HIF-1α in cardiac metabolic adaptation to CH was investigated with genetically modified animals and isotope-labeled metabolomic pathway tracing studies. RESULTS Prepubertal patients with CCHD had glucose-dominant cardiac metabolism and normal cardiac function. In comparison, among patients who had entered puberty, the levels of myocardial glucose uptake and glycolytic intermediates were significantly decreased, but fatty acids were significantly increased, along with decreased left ventricular ejection fraction. These clinical phenotypes were replicated in CH rodent models. In patients with CCHD and animals exposed to CH, myocardial HIF-1α was upregulated before puberty but was significantly downregulated during puberty. In cardiomyocyte-specific Hif-1α-knockout mice, CH failed to initiate the switch of myocardial substrates from fatty acids to glucose, thereby inhibiting ATP production and impairing cardiac function. Increased insulin resistance during puberty suppressed myocardial HIF-1α and was responsible for cardiac metabolic maladaptation in animals exposed to CH. Pioglitazone significantly reduced myocardial insulin resistance, restored glucose metabolism, and improved cardiac function in pubertal CH animals. CONCLUSIONS In patients with CCHD, maladaptation of cardiac metabolism occurred during puberty, along with impaired cardiac function. HIF-1α was identified as the key regulator of cardiac metabolic adaptation in animals exposed to CH, and pubertal insulin resistance could suppress its expression. Pioglitazone administration during puberty might help improve cardiac function in patients with CCHD.
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Affiliation(s)
- Yiwei Liu
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China (Y.L., J.X., L.X., H.Z.).,Shanghai Clinical Research Center for Rare Pediatric Diseases, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China (Y.L., H.Z.)
| | - Qipeng Luo
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.).,Department of Anesthesia, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., X.W., F.Y.).,Pain Medicine Center, Peking University Third Hospital, Beijing, China (Q.L.)
| | - Zhanhao Su
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.)
| | - Junyue Xing
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China (Y.L., J.X., L.X., H.Z.)
| | - Jinlin Wu
- Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (J.W.)
| | - Li Xiang
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China (Y.L., J.X., L.X., H.Z.)
| | - Yuan Huang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.)
| | - Haizhou Pan
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.).,Children's Heart Center, the Second Affiliated Hospital and Yuying Children's Hospital, Institute of Cardiovascular Development and Translational Medicine, Wenzhou Medical University, Zhejiang, China (H.P.)
| | - Xie Wu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.).,Department of Anesthesia, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., X.W., F.Y.)
| | - Xiaoling Zhang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.)
| | - Jun Li
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.)
| | - Fuxia Yan
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., Z.S., Y.H., H.P., X.W., X.Z., J.L., F.Y.).,Department of Anesthesia, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China (Q.L., X.W., F.Y.)
| | - Hao Zhang
- Heart Center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China (Y.L., J.X., L.X., H.Z.).,Shanghai Clinical Research Center for Rare Pediatric Diseases, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China (Y.L., H.Z.)
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Su Z, Liu Y, Zhang H. Adaptive Cardiac Metabolism Under Chronic Hypoxia: Mechanism and Clinical Implications. Front Cell Dev Biol 2021; 9:625524. [PMID: 33604337 PMCID: PMC7884626 DOI: 10.3389/fcell.2021.625524] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/11/2021] [Indexed: 11/29/2022] Open
Abstract
Chronic hypoxia is an essential component in many cardiac diseases. The heart consumes a substantial amount of energy and it is important to maintain the balance of energy supply and demand when oxygen is limited. Previous studies showed that the heart switches from fatty acid to glucose to maintain metabolic efficiency in the adaptation to chronic hypoxia. However, the underlying mechanism of this adaptive cardiac metabolism remains to be fully characterized. Moreover, how the altered cardiac metabolism affects the heart function in patients with chronic hypoxia has not been discussed in the current literature. In this review, we summarized new findings from animal and human studies to illustrate the mechanism underlying the adaptive cardiac metabolism under chronic hypoxia. Clinical focus is given to certain patients that are subject to the impact of chronic hypoxia, and potential treatment strategies that modulate cardiac metabolism and may improve the heart function in these patients are also summarized.
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Affiliation(s)
- Zhanhao Su
- State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yiwei Liu
- Heart center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hao Zhang
- Heart center and Shanghai Institute of Pediatric Congenital Heart Disease, Shanghai Children's Medical Center, National Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
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de Wijs‐Meijler DPM, Duncker DJ, Danser AHJ, Reiss IKM, Merkus D. Changes in the nitric oxide pathway of the pulmonary vasculature after exposure to hypoxia in swine model of neonatal pulmonary vascular disease. Physiol Rep 2018; 6:e13889. [PMID: 30375198 PMCID: PMC6205946 DOI: 10.14814/phy2.13889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 09/12/2018] [Accepted: 09/16/2018] [Indexed: 11/24/2022] Open
Abstract
Neonatal pulmonary vascular disease (PVD) is increasingly recognized as a disease that complicates the cardiopulmonary adaptations after birth and predisposes to long-term cardiopulmonary disease. There is growing evidence that PVD is associated with disruptions in the nitric oxide (NO)-cGMP-phosphodiesterase 5 (PDE5) pathway. Examination of the functionality of different parts of this pathway is required for better understanding of the pathogenesis of neonatal PVD. For this purpose, the role of the NO-cGMP-PDE5 pathway in regulation of pulmonary vascular function was investigated in vivo, both at rest and during exercise, and in isolated pulmonary small arteries in vitro, in a neonatal swine model with hypoxia-induced PVD. Endothelium-dependent vasodilatation was impaired in piglets with hypoxia-induced PVD both in vivo at rest and in vitro. Moreover, the responsiveness to the NO-donor SNP was reduced in hypoxia-exposed piglets in vivo, while the relaxation to SNP and 8-bromo-cyclicGMP in vitro were unaltered. Finally, PDE5 inhibition-induced pulmonary vasodilatation was impaired in hypoxia-exposed piglets both in vitro and in vivo at rest. During exercise, however, the pulmonary vasodilator effect of PDE5 inhibition was significantly larger in hypoxia-exposed as compared to normoxia-exposed piglets. In conclusion, the impaired endothelium-dependent vasodilatation in piglets with hypoxia-induced PVD was accompanied by reduced responsiveness to NO, potentially caused by altered sensitivity and/or activity of soluble guanylyl cyclase (sGC), resulting in an impaired cGMP production. Our findings in a newborn animal model for neonatal PVD suggests that sGC stimulators/activators may be a novel treatment strategy to alleviate neonatal PVD.
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Affiliation(s)
- Daphne P. M. de Wijs‐Meijler
- Division of Experimental CardiologyDepartment of CardiologyUniversity Medical Center RotterdamErasmus MCRotterdamThe Netherlands
- Division of NeonatologyDepartment of PediatricsSophia Children's HospitalErasmus MCUniversity Medical Center RotterdamRotterdamThe Netherlands
| | - Dirk J. Duncker
- Division of Experimental CardiologyDepartment of CardiologyUniversity Medical Center RotterdamErasmus MCRotterdamThe Netherlands
| | - A. H. Jan Danser
- Division of PharmacologyDepartment of Internal MedicineErasmus MC University Medical Center RotterdamRotterdamThe Netherlands
| | - Irwin K. M. Reiss
- Division of NeonatologyDepartment of PediatricsSophia Children's HospitalErasmus MCUniversity Medical Center RotterdamRotterdamThe Netherlands
| | - Daphne Merkus
- Division of Experimental CardiologyDepartment of CardiologyUniversity Medical Center RotterdamErasmus MCRotterdamThe Netherlands
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Eddy AC, Chapman H, George EM. Acute Hypoxia and Chronic Ischemia Induce Differential Total Changes in Placental Epigenetic Modifications. Reprod Sci 2018; 26:766-773. [PMID: 30223723 DOI: 10.1177/1933719118799193] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Preeclampsia is a common obstetrical complication, hallmarked by new-onset hypertension. Believed to result from placental insufficiency and chronic placental ischemia, the symptoms of preeclampsia are caused by release of pathogenic factors from the placenta itself, although the mechanisms of their regulation are in many cases unknown. One potential mechanism is through changes in placental epigenetic chromatin modifications, particularly histone acetylation and DNA methylation. Here, we determined the effects of chronic ischemia on global epigenetic modifications in the rodent placenta in vivo and acute hypoxia in BeWo placental trophoblast cells in vitro. Placental insufficiency via uterine artery restriction increased maternal blood pressure and fetal demise while decreasing placental and fetal mass. Global placental histone H3 acetylation levels were significantly decreased at H3 K9, K14, K18, K27, and K56. Interestingly, when BeWo-immortalized placental trophoblast cells were cultured in oxygen concentrations mimicking healthy and ischemic placentas, there was a significant increase in acetylated at K9, K18, K27, and K56. This was associated with a small but significant decrease in placental acetyl-CoA, suggesting depletion in the source of acetyl group donors. Finally, while global methylation of cytosine from placental DNA was low in both groups of animals (<1%), there was ∼50% increase in 5-mC in response to chronic ischemia. This suggests acute hypoxia and chronic ischemia induce differential global changes in histone acetylation in the placenta and that chronically altered metabolic profiles could affect histone acetylation in the placenta, thereby regulating production of pathogenic factors from the placenta during preeclampsia.
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Affiliation(s)
- Adrian C Eddy
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 N State St, Jackson, MS, 39216, USA
| | - Heather Chapman
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 N State St, Jackson, MS, 39216, USA
| | - Eric M George
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 N State St, Jackson, MS, 39216, USA. .,Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS, USA.
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Jiang S, Jin F, Li D, Zhang X, Yang Y, Yang D, Li K, Yang Y, Ma S. Intermittent hypobaric hypoxia promotes atherosclerotic plaque instability in ApoE-deficient mice. High Alt Med Biol 2014; 14:175-80. [PMID: 23795739 DOI: 10.1089/ham.2012.1083] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
AIM Sudden cardiac death is one of the most frequent causes of death at high altitude. It has been reported that the intermittent normobaric hypoxia experienced by patients with obstructive sleep apnea may enhance the development of atherosclerosis. However, the effect of hypobaric hypoxia, which mimics the ambient air at high altitude, in the development of atherosclerosis has not been investigated. METHODS Twenty male ApoE-deficient mice, 8 weeks of age, were subjected to either control conditions or intermittent hypobaric hypoxia (IHH) for 8 weeks. Mice in the IHH group were exposed to a hypobaric chamber that replicated the hypobaric hypoxia conditions found at 4000 m altitude for 8 hours a day. RESULTS IHH-exposed mice did not significantly differ from control mice in plasma lipid levels, including triglyceride, total cholesterol, low-density lipoprotein, and high-density lipoprotein. The hematoxylin and eosin-stained sections of the aortic root showed similar plaque size between the groups. However, IHH-treated mice exhibited significantly decreased plaque collagen content, a feature of atherosclerotic plaque stability. Additionally, matrix metalloproteinase (MMP)-9 protein expression was significantly increased, whereas tissue inhibitor of MMP (TIMP)-2 expression was decreased after exposure to IHH. CONCLUSION IHH may promote atherosclerotic plaque instability in ApoE-deficient mice by changing the balance of MMPs and TIMPs.
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Affiliation(s)
- Sihua Jiang
- Department of Cardiology, General Hospital of PLA Chengdu Military Area Command, Chengdu, People's Republic of China
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Myocardial expression of heat shock protein 70i protects early postoperative right ventricular function in cyanotic tetralogy of Fallot. J Thorac Cardiovasc Surg 2011; 141:1184-91. [DOI: 10.1016/j.jtcvs.2011.01.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 01/01/2011] [Accepted: 01/24/2011] [Indexed: 11/21/2022]
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Abstract
Sensitivity of pancreatic islets to hypoxia is one of the most important of the obstacles responsible for their failure to survive within the recipients. The aim of this study was to compare the in vitro hypoxia tolerance of neonatal and adult rat islet cells and to study the glucose metabolism in these cells after exposure to hypoxia. Islet cells from both age categories were cultured in different hypoxic levels for 24 h and insulin secretion and some metabolites of glucose metabolism were analysed. Glucose-stimulated insulin secretion decreased dramatically in both cell preparations in response to the decrease in oxygen level. The reduction of insulin secretion was more detectable in adult cells and started at 5% O(2), while a significant reduction was obtained at 1% O(2) in neonatal cells. Moreover, basal insulin release of neonatal cells showed an adaptation to hypoxia after a 4-day culture in hypoxia. Intracellular pyruvate was higher in neonatal cells than in adult ones, while no difference in lactate level was observed between them. Similar results to that of pyruvate were observed for adenosine triphosphate (ATP) and the second messenger cyclic adenosine monophosphate (cAMP). The study reveals that neonatal rat islet cells are more hypoxia-tolerant than the adult ones. The most obvious metabolic observation was that both pyruvate and lactate were actively produced in neonatal cells, while adult cells depended mainly on lactate production as an end-product of glycolysis, indicating a more enhanced metabolic flexibility of neonatal cells to utilize the available oxygen and, at the same time, maintain metabolism anaerobically.
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Affiliation(s)
- Ayman Hyder
- Department of Physiology and Biochemistry of Nutrition, Max Rubner Institute, and Clinical Research Center, Innovation and Technology centre, Kiel, Germany
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8
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Uy RG, Ross-Ascuitto NT, Ascuitto RJ. Recovery of the chronically hypoxic young rabbit heart reperfused following no-flow ischemia. Pediatr Cardiol 2006; 27:37-46. [PMID: 16391992 DOI: 10.1007/s00246-005-1094-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The objective of this study was to test whether chronically hypoxic immature hearts exhibit greater tolerance to no-flow ischemia than normoxic hearts. Rabbits (N = 36) were raised from birth to 5 weeks of age in either hypoxic (10% O2/90% N2) or normoxic (room air) environment. Isolated, isovolumically beating hearts, with a fluid-filled balloon catheter in the left ventricular chamber, were perfused with a well-oxygenated buffer and studied during baseline [30 minutes; perfusion pressure, 60 mmHg; end diastolic pressure (EDP), 5 mmHg], no-flow ischemia (until onset of contracture or for 30 minutes), and Reperfusion (30 minutes; perfusion pressure, 60 mmHg). Time for onset of contracture (TOC) was defined by an increase in balloon pressure of 5 mmHg. The results were as follows: hypoxic vs normoxic: Hct, 56.4 +/- 2.5* vs 36.3 +/- 0.4%, (right ventricle/left ventricle) weight (dry) ratio, 0.50 +/- 0.04* vs 0.28 +/- 0.02. Baseline: developed pressure (DeltaP), 96 +/- 4 vs 93 +/- 5 mmHg; coronary flow, 90 +/- 10* vs 62 +/- 4 ml/min/gdry. No-flow ischemia: TOC, 12 +/- 1* vs 24 +/- 2 minutes. All hypoxic (no normoxic) hearts reached peak contracture. Reperfusion: Just after onset of contracture, DeltaP, 80 +/- 3* vs 67 +/- 4 mmHg; EDP, 5 +/- 1* vs 13 +/- 2 mmHg; after 30 minutes of no-flow ischemia, DeltaP, 58 +/- 5 vs 46 +/- 4 mmHg; EDP, 13 +/- 1* vs 24 +/- 3 mmHg; lactate release (LR), 0.15 +/- 0.01 vs 0.17 +/- 0.01 mmol/gdry, creatine kinase release (CKR), 46 +/- 8* vs 242 +/- 28 U/gdry. For hypoxic hearts reperfused after onset of contracture, LR was 0.11 +/- 0.03 mmol/gdry, comparable to that following 30 minutes of no-flow ischemia (*p < 0.05). Rabbit hearts subjected to hypoxia from birth developed ischemic contracture earlier and reached peak contracture, showed no significant increase in LR after onset of contracture, exhibited better recovery of EDP, and had markedly reduced CKR compared to normoxic controls.
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Affiliation(s)
- R G Uy
- Department of Pediatric Cardiology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70112, USA
| | - N T Ross-Ascuitto
- Department of Pediatric Cardiology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70112, USA
| | - R J Ascuitto
- Department of Pediatric Cardiology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70112, USA.
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Cataldi A, Rapino C, Bianchi G, Centurione L, Zingariello M, Di Giulio C, Antonucci A. Balance between hypertrophic and hypoxic stimulus in caspase-3 activation during rat heart development. J Mol Histol 2005; 36:217-24. [PMID: 15900413 DOI: 10.1007/s10735-005-3282-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 03/07/2005] [Indexed: 11/24/2022]
Abstract
During heart development, cell hyperplasia and hypertrophy are the main mechanisms by which cardiac mass grows. Both these processes along with programmed cell death lead to complete growth and function. In addition, since the establishment of cardiac function depends on the relationship between oxygen supply and demand, we investigated some of the molecular mechanisms at the basis of rat myocardial cell response to hypoxic stress at different times of neonatal life. In particular, the role played by hypertrophic and survival factors like NF-kB and IAP-1 (Inhibiting Apoptosis Protein) and by death factors ASK-1 (Apoptosis Signal Regulating Kinase), JNK/SAPK (Jun-N-Terminal-Kinase/Stress-Activated Protein Kinase) pathways in regulating caspase-3 expression and activity has been evaluated by immunohistochemical and Western blotting analyses, respectively. Level of phosphorylation of IkBalpha and IAP-1 expression were substantial in 8-day-old hypoxic hearts, suggesting the persistence of NF-kB driven hypertrophic signal along with a rescue attempt against hypoxic stress. In contrast, ASK-1 mediated JNK/SAPK activation, regulating Bcl(2) levels, allows Bax homodimerization and caspase-3 activation in the same experimental conditions. Thus, a regulation carried out by NF-kB and JNK/SAPK pathways on caspase-3 activation at day 8 of neonatal life can be suggested as the main factor for the heart 'adaptive' response to hypoxia.
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Affiliation(s)
- A Cataldi
- Dipartimento di Biomorfologia, Università G. D'Annunzio, Via dei Vestini 6, Chieti-Pescara 66100, Italy.
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Ross-Ascuitto NT, Joyce JJ, Hasan AZMA, Ascuitto RJ. Performance of the chronically hypoxic young rabbit heart. Pediatr Cardiol 2004; 25:397-405. [PMID: 14743303 DOI: 10.1007/s00246-003-0429-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Hearts isolated from 30 rabbits, raised from birth to approximately 5 weeks of age under either hypoxic (FIO2, 0.10) or normoxic (FIO2, 0.21) conditions, underwent retrograde aortic perfusion using a non-recirculating, well-oxygenated crystalloid solution. The left ventricular end diastolic pressure was initially set at approximately 5 mmHg. Aerobic performance was studied by measuring peak systolic pressure (PSP), coronary flow, glucose oxidation, and oxygen consumption. Anaerobic function was assessed by determining time for the onset of contracture (TOC) in the presence of zero coronary flow. Hypoxic vs normoxic hearts (mean+/-SEM): heart rate, 197+/-6 vs 190+/-5 beats per minute; PSP, 136+/-4* vs 108+/-4 mmHg; dP/dt(max), 2294+/-125* vs 1549+/-144 mmHg/sec; relaxation time constant (Tau), 26.9+/-1.1* vs 41.6+/-4.8 msec; (-) dP/dt(max), 1422+/-43* vs 1001+/-63 mmHg/sec; coronary flow, 86.3+/-4.2* vs 59.9+/-2.9 ml/min/g(dry); glucose oxidation, 3511+/-118* vs 2979+/-233 nmol/min/g(dry); oxygen consumption, 28.2+/-1.4* vs 22.7+/-1.4 micromol/min/g(dry); and TOC, 11.8+/-1.2* vs 22.9+/-2.2 min (*p < 0.05). Hearts isolated from young rabbits, exposed to hypoxia from birth, exhibited enhanced ventricular systolic and diastolic mechanical function, elevated coronary flow, retained capacity for aerobic metabolism, and a shorter TOC compared to their normoxic counterparts.
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Affiliation(s)
- N T Ross-Ascuitto
- Department of Pediatric Cardiology, Tulane University School of Medicine, New Orleans, LA 70112, USA.
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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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Milano G, Corno AF, Lippa S, Von Segesser LK, Samaja M. Chronic and intermittent hypoxia induce different degrees of myocardial tolerance to hypoxia-induced dysfunction. Exp Biol Med (Maywood) 2002; 227:389-97. [PMID: 12037128 DOI: 10.1177/153537020222700604] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Chronic hypoxia (CH) is believed to induce myocardial protection, but this is in contrast with clinical evidence. Here, we test the hypothesis that repeated brief reoxygenation episodes during prolonged CH improve myocardial tolerance to hypoxia-induced dysfunction. Male 5-week-old Sprague-Dawley rats (n = 7-9/group) were exposed for 2 weeks to CH (F(I)O(2) = 0.10), intermittent hypoxia (IH, same as CH, but 1 hr/day exposure to room air), or normoxia (N, F(I)O(2) = 0.21). Hearts were isolated, Langendorff perfused for 30 min with hypoxic medium (Krebs-Henseleit, PO(2) = 67 mmHg), and exposed to hyperoxia (PO(2) = 670 mm Hg). CH hearts displayed higher end-diastolic pressure, lower rate x pressure product, and higher vascular resistance than IH. During hypoxic perfusion, anaerobic mechanisms recruitment was similar in CH and IH hearts, but less than in N. Thus, despite differing only for 1 hr daily exposure to room air, CH and IH induced different responses in animal homeostasis, markers of oxidative stress, and myocardial tolerance to reoxygenation. We conclude that the protection in animals exposed to CH appears conferred by the hypoxic preconditioning due to the reoxygenation rather than by hypoxia per se.
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Baker JE, Holman P, Kalyanaraman B, Pritchard KA. Adaptation of hearts to chronic hypoxia increases tolerance to subsequent ischemia by increased nitric oxide production. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2001; 454:203-17. [PMID: 9889894 DOI: 10.1007/978-1-4615-4863-8_25] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- J E Baker
- Department of Cardiothoracic Surgery, Medical College of Wisconsin 53226, USA
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Lewis AM, Mathieu-Costello O, McMillan PJ, Gilbert RD. Quantitative electron microscopic study of the hypoxic fetal sheep heart. THE ANATOMICAL RECORD 1999; 256:381-8. [PMID: 10589024 DOI: 10.1002/(sici)1097-0185(19991201)256:4<381::aid-ar5>3.0.co;2-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In order to determine the effects of chronic, high-altitude hypoxia on the ovine fetal heart, we exposed pregnant ewes to 3,820 m beginning at 30 days gestation. We previously showed that following approximately 110 days of hypoxia the fetal heart showed significant reduction in cardiac output (76% of control) and contractility, and elevated levels of citrate synthase and lactate dehydrogenase. To investigate ultrastructural influences on these observed physiologic changes at altitude, we hypothesized that the volume densities of myofibrils and mitochondria, and glycogen content would be reduced in the ovine fetal heart and that this may contribute to contraction and cardiac output deficits in hypoxia. Mitochondria and myofibril volume density were determined by standard point-counting techniques and glycogen content was determined by biochemical analysis. The glycogen content from the hypoxic right ventricle (4.8 +/- 0.3%) was significantly lower than in control right ventricle (6.8 +/- 0.5%) and both left ventricles (hypoxia, 7.2 +/- 0.5; control, 7.8 +/- 0. 4%). Total mitochondrial volume density was also significantly reduced following hypoxia (15.5 +/- 0.7%) compared to controls (16.9 +/- 0.4%). As is common in the ovine fetal heart, the myofibril volume density of the right ventricle from both groups was significantly higher than the left ventricle (RV, 58.6 +/- 1.6; LV 54.3 +/- 0.9%). However, it was not different between control and high altitude. In support of our hypothesis, we may speculate that deficits in the quantity of myocyte glycogen and mitochondria contribute to the observed reduction in cardiac output and contractility, despite the upregulation of citrate synthase and lactate dehydrogenase. In contrast, myofibril volume density was unchanged.
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Affiliation(s)
- A M Lewis
- Center for Perinatal Biology, Loma Linda Medical School, Loma Linda, California 92350, USA.
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Baker JE, Holman P, Kalyanaraman B, Griffith OW, Pritchard KA. Adaptation to chronic hypoxia confers tolerance to subsequent myocardial ischemia by increased nitric oxide production. Ann N Y Acad Sci 1999; 874:236-53. [PMID: 10415535 DOI: 10.1111/j.1749-6632.1999.tb09239.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chronic exposure to hypoxia from birth increased the tolerance of the rabbit heart to subsequent ischemia compared with age-matched normoxic controls. The nitric oxide donor GSNO increased recovery of post-ischemic function in normoxic hearts to values not different from hypoxic controls, but had no effect on hypoxic hearts. The nitric oxide synthase inhibitors L-NAME and L-NMA abolished the cardioprotective effect of hypoxia. Message and catalytic activity for constitutive nitric oxide synthase as well as nitrite, nitrate, and cGMP levels were elevated in hypoxic hearts. Inducible nitric oxide synthase was not detected in normoxic or chronically hypoxic hearts. Increased tolerance to ischemia in rabbit hearts adapted to chronic hypoxia is associated with increased expression of constitutive nitric oxide synthase.
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Affiliation(s)
- J E Baker
- Department of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee 53226, USA.
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Abdel-Aleem S, St Louis JD, Hughes GC, Lowe JE. Metabolic changes in the normal and hypoxic neonatal myocardium. Ann N Y Acad Sci 1999; 874:254-61. [PMID: 10415536 DOI: 10.1111/j.1749-6632.1999.tb09240.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hypoxia is characterized by inadequate oxygen delivery to the myocardium with a resulting imbalance between oxygen demand and energy supply. Several adaptive mechanisms occur to preserve myocardial survival during hypoxia. These include both short- and long-term mechanisms, which serve to achieve a new balance between myocardial oxygen demand and energy production. Short-term adaptation includes downregulation of myocardial function along with upregulation of energy production via anaerobic glycolysis following an increase in glucose uptake and glycogen breakdown. Long-term adaptation includes genetic reprogramming of key glycolytic enzymes. Thus, the initial decline in high-energy phosphates following hypoxia is accompanied by a decrease in myocardial contractility and myocardial energy requirements are subsequently met by ATP supplied from anaerobic glycolysis. Thus, a downregulation in cardiac function and/or enhanced energy production via anaerobic glycolysis are the major mechanisms promoting myocardial survival during hypoxia. In contrast to the aforementioned metabolic changes occurring in adult myocardium, the effects of chronic hypoxia on neonatal myocardial metabolism remain undefined. Studies from our laboratory using a novel neonatal piglet model of chronic hypoxia have shown a shift in cardiac myocyte substrate utilization towards the newborn state with a preference for glucose utilization. We have also shown, using this same model, that chronically hypoxic neonatal hearts were more tolerant to ischemia than non-hypoxic hearts. This ischemic tolerance is likely due to adaptive metabolic changes in the chronically hypoxic hearts, such as increased anaerobic glycolysis and glycogen breakdown.
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Affiliation(s)
- S Abdel-Aleem
- Division of Thoracic Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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Merante F, Mickle DA, Weisel RD, Li RK, Tumiati LC, Rao V, Williams WG, Robinson BH. Myocardial aerobic metabolism is impaired in a cell culture model of cyanotic heart disease. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:H1673-81. [PMID: 9815075 DOI: 10.1152/ajpheart.1998.275.5.h1673] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A human pediatric cardiomyocyte cell culture model of chronic cyanosis was used to assess the effects of low oxygen tension on mitochondrial enzyme activity to address the postoperative increase in lactate and decreased ATP in the myocardium and the high incidence of low-output failure with restoration of normal oxygen tension, after technically successful corrective cardiac surgery. Chronically hypoxic cells (PO2 = 40 mmHg for 7 days) exhibited significantly reduced activities for pyruvate dehydrogenase, cytochrome-c oxidase, succinate cytochrome c reductase, succinate dehydrogenase, and citrate synthase. The activity of NADH-cytochrome c reductase was unaffected. Lactate production and the lactate-to-pyruvate ratio were significantly greater in hypoxic cardiomyocytes. Western and Northern analysis demonstrated a decrease in the levels of various mRNA and corresponding polypeptides in hypoxic cells. Thus hypoxia influences mitochondrial metabolism through acute and chronic adaptive mechanisms, reflecting allosteric (posttranscriptional) and transcriptional modulation. Transcriptional downregulation of key mitochondrial enzyme systems can explain the insufficient myocardial aerobic metabolism and low-output failure in children with cyanotic heart disease after cardiac surgery.
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Affiliation(s)
- F Merante
- Centre for Cardiovascular Research, The Toronto Hospital and the University of Toronto, Toronto, Ontario, Canada M5G 2C4
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