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Dugbartey GJ. Therapeutic benefits of nitric oxide in lung transplantation. Biomed Pharmacother 2023; 167:115549. [PMID: 37734260 DOI: 10.1016/j.biopha.2023.115549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/06/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023] Open
Abstract
Lung transplantation is an evolutionary procedure from its experimental origin in the twentieth century and is now recognized as an established and routine life-saving intervention for a variety of end-stage pulmonary diseases refractory to medical management. Despite the success and continuous refinement in lung transplantation techniques, the widespread application of this important life-saving intervention is severely hampered by poor allograft quality offered from donors-after-brain-death. This has necessitated the use of lung allografts from donors-after-cardiac-death (DCD) as an additional source to expand the pool of donor lungs. Remarkably, the lung exhibits unique properties that may make it ideally suitable for DCD lung transplantation. However, primary graft dysfunction (PGD), allograft rejection and other post-transplant complications arising from unavoidable ischemia-reperfusion injury (IRI) of transplanted lungs, increase morbidity and mortality of lung transplant recipients annually. In the light of this, nitric oxide (NO), a selective pulmonary vasodilator, has been identified as a suitable agent that attenuates lung IRI and prevents PGD when administered directly to lung donors prior to donor lung procurement, or to recipients during and after transplantation, or administered indirectly by supplementing lung preservation solutions. This review presents a historical account of clinical lung transplantation and discusses the lung as an ideal organ for DCD. Next, the author highlights IRI and its clinical effects in lung transplantation. Finally, the author discusses preservation solutions suitable for lung transplantation, and the protective effects and mechanisms of NO in experimental and clinical lung transplantation.
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Affiliation(s)
- George J Dugbartey
- Department of Pharmacology and Toxicology, School of Pharmacy, College of Health Sciences, University of Ghana, Legon, Accra, Ghana; Accra College of Medicine, Magnolia St, JVX5+FX9, East Legon, Accra, Ghana.
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Orzabal MR, Naik VD, Lee J, Wu G, Ramadoss J. Impact of gestational electronic cigarette vaping on amino acid signature profile in the pregnant mother and the fetus. Metabol Open 2021; 11:100107. [PMID: 34355157 PMCID: PMC8319793 DOI: 10.1016/j.metop.2021.100107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/10/2021] [Accepted: 07/11/2021] [Indexed: 11/25/2022] Open
Abstract
Background Electronic cigarettes (e-cigs) are a form of tobacco product that has become increasingly popular over the past decade. Despite the known health consequences of tobacco product exposure during pregnancy, a substantial number of daily smokers will continue to smoke during pregnancy. Our current knowledge on the effects of e-cig aerosol exposure during pregnancy is limited to a small number of animal studies, which have identified several e-cig aerosol-induced disruptions to the physiology of normal development. Methods To further assess the impact of prenatal e-cig aerosol exposure on maternal and fetal health, we examined the amino acid signature profiles in maternal and fetal plasma, as well as in the fetal lungs, a sensitive target organ for prenatal tobacco product exposure. Pregnant Sprague Dawley rats were randomly assigned to one of three groups and were exposed to either e-cig aerosols containing nicotine, e-cig aerosols without nicotine, or room air. Dams were exposed utilizing a state-of-the-art custom engineered e-cig vaping system that is compatible with commercially available e-cig atomizers and enables a translational inhalation delivery method comparable to human vaping. Results We determined that gestational exposure to e-cig aerosols results in significant alterations to the amino acid profile in the maternal and fetal compartments, including the fetal lungs. The data shows a targeted disruption to the nitric oxide pathway, branched-chain amino acid metabolism, fetal protein synthesis, and urea cycle. Conclusion The data presented herein provides additional support that gestational e-cig aerosol exposure can impact crucial biological processes and exemplifies the need for extensive research on exposure to e-cig aerosols. First report of e-cig induced alterations to maternal/fetal amino acid profile. Translational vaping paradigm utilizing custom engineered vaping system. Analysis of amino acids show gestational e-cig exposure has significant effects. Fetal lungs may be a sensitive target to gestational e-cig aerosol exposure. Marker of dysregulation in branched-chain amino acid metabolism and urea cycle.
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Affiliation(s)
- Marcus R Orzabal
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Vishal D Naik
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Jehoon Lee
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Guoyao Wu
- Department of Animal Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, USA
| | - Jayanth Ramadoss
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
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Childebayeva A, Goodrich JM, Leon-Velarde F, Rivera-Chira M, Kiyamu M, Brutsaert TD, Dolinoy DC, Bigham AW. Genome-Wide Epigenetic Signatures of Adaptive Developmental Plasticity in the Andes. Genome Biol Evol 2020; 13:5981114. [PMID: 33185669 PMCID: PMC7859850 DOI: 10.1093/gbe/evaa239] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2020] [Indexed: 01/03/2023] Open
Abstract
High-altitude adaptation is a classic example of natural selection operating on the human genome. Physiological and genetic adaptations have been documented in populations with a history of living at high altitude. However, the role of epigenetic gene regulation, including DNA methylation, in high-altitude adaptation is not well understood. We performed an epigenome-wide DNA methylation association study based on whole blood from 113 Peruvian Quechua with differential lifetime exposures to high altitude (>2,500) and recruited based on a migrant study design. We identified two significant differentially methylated positions (DMPs) and 62 differentially methylated regions (DMRs) associated with high-altitude developmental and lifelong exposure statuses. DMPs and DMRs were found in genes associated with hypoxia-inducible factor pathway, red blood cell production, blood pressure, and others. DMPs and DMRs associated with fractional exhaled nitric oxide also were identified. We found a significant association between EPAS1 methylation and EPAS1 SNP genotypes, suggesting that local genetic variation influences patterns of methylation. Our findings demonstrate that DNA methylation is associated with early developmental and lifelong high-altitude exposures among Peruvian Quechua as well as altitude-adaptive phenotypes. Together these findings suggest that epigenetic mechanisms might be involved in adaptive developmental plasticity to high altitude. Moreover, we show that local genetic variation is associated with DNA methylation levels, suggesting that methylation associated SNPs could be a potential avenue for research on genetic adaptation to hypoxia in Andeans.
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Affiliation(s)
- Ainash Childebayeva
- Department of Anthropology, University of Michigan.,Department of Environmental Health Sciences, School of Public Health, University of Michigan.,Department of Archaeogenetics, Max Planck Institute for the Study of Human History, Jena, Germany
| | - Jaclyn M Goodrich
- Department of Environmental Health Sciences, School of Public Health, University of Michigan
| | - Fabiola Leon-Velarde
- Departamento de Ciencias Biológicas y Fisiológicas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Maria Rivera-Chira
- Departamento de Ciencias Biológicas y Fisiológicas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Melisa Kiyamu
- Departamento de Ciencias Biológicas y Fisiológicas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Dana C Dolinoy
- Department of Environmental Health Sciences, School of Public Health, University of Michigan.,Department of Nutritional Sciences, School of Public Health, University of Michigan
| | - Abigail W Bigham
- Department of Anthropology, University of California, Los Angeles
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Shi XF, Su YC. Vascular Metabolic Mechanisms of Pulmonary Hypertension. Curr Med Sci 2020; 40:444-454. [PMID: 32681249 DOI: 10.1007/s11596-020-2198-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/10/2020] [Indexed: 02/07/2023]
Abstract
Pulmonary hypertension (PH) is a severe and progressive disease characterized by increased pulmonary vascular resistance leading to right heart failure and death. In PH, the cellular metabolisms including those of the three major nutrients (carbohydrate, lipid and protein) are aberrant in pulmonary vascular cells. Glucose uptake, glycolysis, insulin resistance, sphingolipid S1P, PGE2, TXA2, leukotrienes and glutaminolysis are upregulated, and phospholipid-prostacyclin and L-arginine-nitric oxide pathway are compromised in lung vascular cells. Fatty acid metabolism is disordered in lung endothelial cells and smooth muscle cells. These molecular mechanisms are integrated to promote PH-specific abnormal vascular cell proliferation and vascular remodeling. This review summarizes the recent advances in the metabolic reprogramming of glucose, fatty acid, and amino acid metabolism in pulmonary vascular remodeling in PH and the mechanisms for how these alterations affect vascular cell fate and impact the course of PH.
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Affiliation(s)
- Xiao-Fan Shi
- Department of Pharmacology & Toxicology, Augusta University, Augusta, GA, 30912, USA
| | - Yun-Chao Su
- Department of Pharmacology & Toxicology, Augusta University, Augusta, GA, 30912, USA. .,Department of Medicine, Augusta University, Augusta, GA, 30912, USA. .,Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.
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S-Nitrosylation: An Emerging Paradigm of Redox Signaling. Antioxidants (Basel) 2019; 8:antiox8090404. [PMID: 31533268 PMCID: PMC6769533 DOI: 10.3390/antiox8090404] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 02/07/2023] Open
Abstract
Nitric oxide (NO) is a highly reactive molecule, generated through metabolism of L-arginine by NO synthase (NOS). Abnormal NO levels in mammalian cells are associated with multiple human diseases, including cancer. Recent studies have uncovered that the NO signaling is compartmentalized, owing to the localization of NOS and the nature of biochemical reactions of NO, including S-nitrosylation. S-nitrosylation is a selective covalent post-translational modification adding a nitrosyl group to the reactive thiol group of a cysteine to form S-nitrosothiol (SNO), which is a key mechanism in transferring NO-mediated signals. While S-nitrosylation occurs only at select cysteine thiols, such a spatial constraint is partially resolved by transnitrosylation, where the nitrosyl moiety is transferred between two interacting proteins to successively transfer the NO signal to a distant location. As NOS is present in various subcellular locales, a stress could trigger concerted S-nitrosylation and transnitrosylation of a large number of proteins involved in divergent signaling cascades. S-nitrosylation is an emerging paradigm of redox signaling by which cells confer protection against oxidative stress.
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Fortification of Preservation Solution With Nitroprusside Does Not Alter Lung Allograft Survival in Clinical Human Lung Transplantation. Ochsner J 2019; 19:235-240. [PMID: 31528134 DOI: 10.31486/toj.19.0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Background: Nitric oxide improves gas exchange following primary lung allograft dysfunction. Nitroprusside, a potent nitric oxide donor, has reduced reperfusion injury and improved oxygenation in experimental lung transplantation. Methods: We sought to study the effect on lung allograft outcomes of fortifying the preservation solution with nitroprusside. We conducted a single-center clinical study of 46 consecutive lung recipients between 1998 and 2000: 24 patients received donor organs preserved in modified Euro-Collins solution with prostaglandin E1 (PGE1) (control group), and 22 patients received organs preserved in modified Euro-Collins with PGE1 and nitroprusside (NP group). The primary endpoint was overall survival. Results: Baseline characteristics were similar between the groups except for a significantly longer graft ischemic time in the NP group vs the control group (253.3 ± 52 vs 225.3 ± 41 minutes, respectively, P=0.04). No significant differences were found in partial pressure arterial oxygen to fraction inspired oxygen ratio at ≤48 hours, primary graft dysfunction, or bronchiolitis obliterans-free days. Overall survival at 1, 3, and 5 years was 89%, 73%, and 63% in the control group and 76%, 38%, and 23% in the NP group. Log-rank survival analysis showed that the NP group had a significantly increased risk of mortality (P=0.034) compared to the control group. Conclusion: The addition of nitroprusside to the lung transplant perfusate in this clinical trial did not improve survival; however, a large randomized trial would likely reduce confounding ischemia times and increase the power of the study.
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Ghosh S, Kiyamu M, Contreras P, León-Velarde F, Bigham A, Brutsaert TD. Exhaled nitric oxide in ethnically diverse high-altitude native populations: A comparative study. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 170:451-458. [PMID: 31396964 DOI: 10.1002/ajpa.23915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/25/2019] [Accepted: 07/18/2019] [Indexed: 11/12/2022]
Abstract
OBJECTIVES Andean and Tibetan high-altitude natives exhibit a high concentration of nitric oxide (NO) in the lungs, suggesting that NO plays an adaptive role in offsetting hypobaric hypoxia. We examined the exhaled NO concentration as well as partial pressure of several additional high-altitude native populations in order to examine the possibility that this putative adaptive trait, that is, high exhaled NO, is universal. METHODS We recruited two geographically diverse highland native populations, Tawang Monpa (TM), a Tibetan derived population in North-Eastern India (n = 95, sampled at an altitude of ~3,200 m), and Peruvian Quechua from the highland Andes (n = 412). The latter included three distinct subgroups defined as those residing at altitude (Q-HAR, n = 110, sampled at 4,338 m), those born and residing at sea-level (Q-BSL, n = 152), and those born at altitude but migrant to sea-level (Q-M, n = 150). In addition, we recruited a referent sample of lowland natives of European ancestry from Syracuse, New York. Fraction of exhaled NO concentrations were measured using a NIOX NIMO following the protocol of the manufacturer. RESULTS Partial pressure of exhaled nitric oxide (PENO) was significantly lower (p < .05) in both high-altitude resident groups (TM = 6.2 ± 0.5 nmHg and Q-HAR = 5.8 ± 0.5 nmHg), as compared to the groups measured at sea level (USA = 14.6 ± 0.7 nmHg, Q-BSL = 18.9 ± 1.6 nmHg, and Q-M = 19.2 ± 1.7 nmHg). PENO was not significantly different between TM and Q-HAR (p < .05). CONCLUSION In contrast to previous work, we found lower PENO in populations at altitude (compared to sea-level) and no difference in PENO between Tibetan and Andean highland native populations. These results do not support the hypothesis that high nitric oxide in human lungs is a universal adaptive mechanism of highland native populations to offset hypobaric hypoxia.
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Affiliation(s)
- Sudipta Ghosh
- Department of Anthropology, North-Eastern Hill University, Shillong, Meghalaya, India
| | - Melisa Kiyamu
- Departamento de Ciencias Biológicas y Fisiológicas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Paloma Contreras
- Department of Anthropology, University of Michigan, Ann Arbor, Michigan
| | - Fabiola León-Velarde
- Departamento de Ciencias Biológicas y Fisiológicas, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Abigail Bigham
- Department of Anthropology, University of Michigan, Ann Arbor, Michigan
| | - Tom D Brutsaert
- Department of Exercise Science, Syracuse University, Syracuse, New York
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Smith KA, Schumacker PT. Sensors and signals: the role of reactive oxygen species in hypoxic pulmonary vasoconstriction. J Physiol 2018; 597:1033-1043. [PMID: 30091476 DOI: 10.1113/jp275852] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/20/2018] [Indexed: 12/12/2022] Open
Abstract
When lung cells experience hypoxia, the functional response, termed hypoxic pulmonary vasoconstriction, activates a multitude of pathways with the goal of optimizing gas exchange. While previously controversial, overwhelming evidence now suggests that increased reactive oxygen species - produced at complex III of the mitochondrial electron transport chain and released into the intermembrane space - is the cellular oxygen signal responsible for triggering hypoxic pulmonary vasoconstriction. The increased reactive oxygen species (ROS) activate many downstream targets that ultimately lead to increased intracellular ionized calcium concentration and contraction of pulmonary arterial smooth muscle cells. While the specific targets of ROS signals are not completely understood, it is clear that this signalling pathway is critical for development and for normal lung function in newborns and adults.
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Affiliation(s)
- Kimberly A Smith
- Department of Pediatrics, Division of Neonatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Paul T Schumacker
- Department of Pediatrics, Division of Neonatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Wang X, Cai X, Wang W, Jin Y, Chen M, Huang X, Zhu X, Wang L. Effect of asiaticoside on endothelial cells in hypoxia‑induced pulmonary hypertension. Mol Med Rep 2017; 17:2893-2900. [PMID: 29257311 PMCID: PMC5783505 DOI: 10.3892/mmr.2017.8254] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 11/01/2017] [Indexed: 11/15/2022] Open
Abstract
Pulmonary hypertension (PH) is a chronic progressive disease with limited treatment options. The exact etiology and pathogenesis of PH remain to be elucidated, however there is novel evidence that implicates abnormal endothelial cells (ECs) apoptosis and dysfunction of ECs to be involved in the initiation of PH. Asiaticoside (AS) is a saponin monomer extracted from a medicinal plant called Centella asiatica, which had a preventing effect of hypoxia-induced pulmonary hypertension (hypoxic PH) by blocking transforming growth factor-β1/SMAD family member 2/3 signaling in our previous study. The present study demonstrated that AS can prevent the development of hypoxic PH and reverse the established hypoxic PH. AS may activate the nitric oxide (NO)-mediated signals by enhancing the phosphorylation of serine/threonine-specific protein kinase/eNOS, thus promoting NO production, and prevent ECs from hypoxia-induced apoptosis. All these findings imply that AS may be a potential therapeutic option for hypoxic PH patients due to its effect on the vitality and function of endothelial cells.
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Affiliation(s)
- Xiaobing Wang
- Department of Rheumalogy, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Xueli Cai
- Department of Cardiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Wu Wang
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Yi Jin
- Department of Rheumalogy, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Mayun Chen
- Key Laboratory of Heart and Lung, Respiratory Department, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Xiaoying Huang
- Key Laboratory of Heart and Lung, Respiratory Department, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Xiaochun Zhu
- Department of Rheumalogy, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Liangxing Wang
- Key Laboratory of Laboratory Medicine, Ministry of Education of China, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
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Abstract
Hypoxic pulmonary vasoconstriction (HPV) in combination with hypercapnic pulmonary vasoconstriction redistributes pulmonary blood flow from poorly aerated to better ventilated lung regions by an active process of local vasoconstriction. Impairment of HPV results in ventilation-perfusion mismatch and is commonly associated with various lung diseases including pneumonia, sepsis, or cystic fibrosis. Although several regulatory pathways have been identified, considerable knowledge gaps persist, and a unifying concept of the signaling pathways that underlie HPV and their impairment in lung diseases has not yet emerged. In the past, conceptual models of HPV have focused on pulmonary arterial smooth muscle cells (PASMC) acting as sensor and effector of hypoxia in the pulmonary vasculature. In contrast, the endothelium was considered a modulating bystander in this scenario. For an ideal design, however, the oxygen sensor in HPV should be located in the region of gas exchange, i.e., in the alveolar capillary network. This concept requires the retrograde propagation of the hypoxic signal along the endothelial layer of the vascular wall and subsequent contraction of PASMC in upstream arterioles that is elicited via temporospatially tightly controlled endothelial-smooth muscle cell crosstalk. The present review summarizes recent work that provides proof-of-principle for the existence and functional relevance of such signaling pathway in HPV that involves important roles for connexin 40, epoxyeicosatrienoic acids, sphingolipids, and cystic fibrosis transmembrane conductance regulator. Of translational relevance, implication of these molecules provides for novel mechanistic explanations for impaired ventilation/perfusion matching in patients with pneumonia, sepsis, cystic fibrosis, and presumably various other lung diseases.
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Affiliation(s)
- Benjamin Grimmer
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin , Germany
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité Universitätsmedizin Berlin, Berlin , Germany
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital , Toronto, Ontario , Canada
- Departments of Surgery and Physiology, University of Toronto , Toronto, Ontario , Canada
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Oczypok EA, Perkins TN, Oury TD. Alveolar Epithelial Cell-Derived Mediators: Potential Direct Regulators of Large Airway and Vascular Responses. Am J Respir Cell Mol Biol 2017; 56:694-699. [PMID: 28080134 DOI: 10.1165/rcmb.2016-0151ps] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bronchial epithelial cells and pulmonary endothelial cells are thought to be the primary modulators of conducting airways and vessels, respectively. However, histological examination of both mouse and human lung tissue reveals that alveolar epithelial cells (AECs) line the adventitia of large airways and vessels and thus are also in a position to directly regulate these structures. The primary purpose of this perspective is to highlight the fact that AECs coat the adventitial surface of every vessel and airway in the lung parenchyma. This localization is ideal for transmitting signals that can contribute to physiologic and pathologic responses in vessels and airways. A few examples of mediators produced by AECs that may contribute to vascular and airway responses are provided to illustrate some of the potential effects that AECs may modulate.
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Affiliation(s)
- Elizabeth A Oczypok
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Timothy N Perkins
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Tim D Oury
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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Kylhammar D, Rådegran G. The principal pathways involved in the in vivo modulation of hypoxic pulmonary vasoconstriction, pulmonary arterial remodelling and pulmonary hypertension. Acta Physiol (Oxf) 2017; 219:728-756. [PMID: 27381367 DOI: 10.1111/apha.12749] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 06/10/2016] [Accepted: 07/04/2016] [Indexed: 12/13/2022]
Abstract
Hypoxic pulmonary vasoconstriction (HPV) serves to optimize ventilation-perfusion matching in focal hypoxia and thereby enhances pulmonary gas exchange. During global hypoxia, however, HPV induces general pulmonary vasoconstriction, which may lead to pulmonary hypertension (PH), impaired exercise capacity, right-heart failure and pulmonary oedema at high altitude. In chronic hypoxia, generalized HPV together with hypoxic pulmonary arterial remodelling, contribute to the development of PH. The present article reviews the principal pathways in the in vivo modulation of HPV, hypoxic pulmonary arterial remodelling and PH with primary focus on the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways. In summary, endothelin-1 and thromboxane A2 may enhance, whereas nitric oxide and prostacyclin may moderate, HPV as well as hypoxic pulmonary arterial remodelling and PH. The production of prostacyclin seems to be coupled primarily to cyclooxygenase-1 in acute hypoxia, but to cyclooxygenase-2 in chronic hypoxia. The potential role of adenine nucleotides in modulating HPV is unclear, but warrants further study. Additional modulators of the pulmonary vascular responses to hypoxia may include angiotensin II, histamine, serotonin/5-hydroxytryptamine, leukotrienes and epoxyeicosatrienoic acids. Drugs targeting these pathways may reduce acute and/or chronic hypoxic PH. Endothelin receptor antagonists and phosphodiesterase-5 inhibitors may additionally improve exercise capacity in hypoxia. Importantly, the modulation of the pulmonary vascular responses to hypoxia varies between species and individuals, with hypoxic duration and age. The review also define how drugs targeting the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways may improve pulmonary haemodynamics, but also impair pulmonary gas exchange by interference with HPV in chronic lung diseases.
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Affiliation(s)
- D. Kylhammar
- Department of Clinical Sciences Lund, Cardiology; Faculty of Medicine; Lund University; Lund Sweden
- The Section for Heart Failure and Valvular Disease; VO Heart and Lung Medicine; Skåne University Hospital; Lund Sweden
| | - G. Rådegran
- Department of Clinical Sciences Lund, Cardiology; Faculty of Medicine; Lund University; Lund Sweden
- The Section for Heart Failure and Valvular Disease; VO Heart and Lung Medicine; Skåne University Hospital; Lund Sweden
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Tan X, Feng L, Huang X, Yang Y, Yang C, Gao Y. Histone deacetylase inhibitors promote eNOS expression in vascular smooth muscle cells and suppress hypoxia-induced cell growth. J Cell Mol Med 2017; 21:2022-2035. [PMID: 28266122 PMCID: PMC5571528 DOI: 10.1111/jcmm.13122] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 01/13/2017] [Indexed: 12/25/2022] Open
Abstract
Hypoxia stimulates excessive growth of vascular smooth muscle cells (VSMCs) contributing to vascular remodelling. Recent studies have shown that histone deacetylase inhibitors (HDIs) suppress VSMC proliferation and activate eNOS expression. However, the effects of HDI on hypoxia-induced VSMC growth and the role of activated eNOS in VSMCs are unclear. Using an EdU incorporation assay and flow cytometry analysis, we found that the HDIs, butyrate (Bur) and suberoylanilide hydroxamic acid (SAHA) significantly suppressed the proliferation of hypoxic VSMC lines and induced apoptosis. Remarkable induction of cleaved caspase 3, p21 expression and reduction of PCNA expression were also observed. Increased eNOS expression and enhanced NO secretion by hypoxic VSMC lines were detected using Bur or SAHA treatment. Knockdown of eNOS by siRNA transfection or exposure of hypoxic VSMCs to NO scavengers weakened the effects of Bur and SAHA on the growth of hypoxic VSMCs. In animal experiments, administration of Bur to Wistar rats exposed to hypobaric hypoxia for 28 days ameliorated the thickness and collagen deposition in pulmonary artery walls. Although the mean pulmonary arterial pressure (mPAP) was not obviously decreased with Bur in hypoxic rats, right ventricle hypertrophy index (RVHI) was decreased and the oxygen partial pressure of arterial blood was elevated. Furthermore, cell viability was decreased and eNOS and cleaved caspase 3 were induced in HDI-treated rat pulmonary arterial SMCs. These findings imply that HDIs prevent hypoxia-induced VSMC growth, in correlation with activated eNOS expression and activity in hypoxic VSMCs.
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Affiliation(s)
- Xiaoling Tan
- Department of High Altitude Physiology & Biology, College of High Altitude Medicine, Third Military Medical University, Chongqing, China
| | - Lan Feng
- Department of High Altitude Physiology & Biology, College of High Altitude Medicine, Third Military Medical University, Chongqing, China
| | - Xiaoyong Huang
- Southwest Eye Hospital, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Yidong Yang
- Department of Pathophysiology & High Altitude Pathology, College of High Altitude Medicine, Third Military Medical University, Chongqing, China
| | - Chengzhong Yang
- Department of High Altitude Physiology & Biology, College of High Altitude Medicine, Third Military Medical University, Chongqing, China
| | - Yuqi Gao
- Department of Pathophysiology & High Altitude Pathology, College of High Altitude Medicine, Third Military Medical University, Chongqing, China
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Chalupsky K, Kračun D, Kanchev I, Bertram K, Görlach A. Folic Acid Promotes Recycling of Tetrahydrobiopterin and Protects Against Hypoxia-Induced Pulmonary Hypertension by Recoupling Endothelial Nitric Oxide Synthase. Antioxid Redox Signal 2015; 23:1076-91. [PMID: 26414244 PMCID: PMC4657514 DOI: 10.1089/ars.2015.6329] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 09/21/2015] [Accepted: 09/21/2015] [Indexed: 01/29/2023]
Abstract
AIMS Nitric oxide (NO) derived from endothelial NO synthase (eNOS) has been implicated in the adaptive response to hypoxia. An imbalance between 5,6,7,8-tetrahydrobiopterin (BH4) and 7,8-dihydrobiopterin (BH2) can result in eNOS uncoupling and the generation of superoxide instead of NO. Dihydrofolate reductase (DHFR) can recycle BH2 to BH4, leading to eNOS recoupling. However, the role of DHFR and eNOS recoupling in the response to hypoxia is not well understood. We hypothesized that increasing the capacity to recycle BH4 from BH2 would improve NO bioavailability as well as pulmonary vascular remodeling (PVR) and right ventricular hypertrophy (RVH) as indicators of pulmonary hypertension (PH) under hypoxic conditions. RESULTS In human pulmonary artery endothelial cells and murine pulmonary arteries exposed to hypoxia, eNOS was uncoupled as indicated by reduced superoxide production in the presence of the nitric oxide synthase inhibitor, L-(G)-nitro-L-arginine methyl ester (L-NAME). Concomitantly, NO levels, BH4 availability, and expression of DHFR were diminished under hypoxia. Application of folic acid (FA) restored DHFR levels, NO bioavailability, and BH4 levels under hypoxia. Importantly, FA prevented the development of hypoxia-induced PVR, right ventricular pressure increase, and RVH. INNOVATION FA-induced upregulation of DHFR recouples eNOS under hypoxia by improving BH4 recycling, thus preventing hypoxia-induced PH. CONCLUSION FA might serve as a novel therapeutic option combating PH.
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Affiliation(s)
- Karel Chalupsky
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Damir Kračun
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Ivan Kanchev
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Katharina Bertram
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
| | - Agnes Görlach
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich at the Technical University Munich, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
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15
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Aberrant maternal inflammation as a cause of pregnancy complications: A potential therapeutic target? Placenta 2015; 36:960-6. [DOI: 10.1016/j.placenta.2015.05.016] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 05/12/2015] [Accepted: 05/25/2015] [Indexed: 12/17/2022]
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16
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Oxidative Stress and Lung Ischemia-Reperfusion Injury. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:590987. [PMID: 26161240 PMCID: PMC4487720 DOI: 10.1155/2015/590987] [Citation(s) in RCA: 174] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 01/19/2015] [Accepted: 01/20/2015] [Indexed: 01/04/2023]
Abstract
Ischemia-reperfusion (IR) injury is directly related to the formation of reactive oxygen species (ROS), endothelial cell injury, increased vascular permeability, and the activation of neutrophils and platelets, cytokines, and the complement system. Several studies have confirmed the destructiveness of the toxic oxygen metabolites produced and their role in the pathophysiology of different processes, such as oxygen poisoning, inflammation, and ischemic injury. Due to the different degrees of tissue damage resulting from the process of ischemia and subsequent reperfusion, several studies in animal models have focused on the prevention of IR injury and methods of lung protection. Lung IR injury has clinical relevance in the setting of lung transplantation and cardiopulmonary bypass, for which the consequences of IR injury may be devastating in critically ill patients.
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Abstract
SIGNIFICANCE The pulmonary circulation is a low-pressure, low-resistance, highly compliant vasculature. In contrast to the systemic circulation, it is not primarily regulated by a central nervous control mechanism. The regulation of resting membrane potential due to ion channels is of integral importance in the physiology and pathophysiology of the pulmonary vasculature. RECENT ADVANCES Redox-driven ion conductance changes initiated by direct oxidation, nitration, and S-nitrosylation of the cysteine thiols and indirect phosphorylation of the threonine and serine residues directly affect pulmonary vascular tone. CRITICAL ISSUES Molecular mechanisms of changes in ion channel conductance, especially the identification of the sites of action, are still not fully elucidated. FUTURE DIRECTIONS Further investigation of the interaction between redox status and ion channel gating, especially the physiological significance of S-glutathionylation and S-nitrosylation, could result in a better understanding of the physiological and pathophysiological importance of these mediators in general and the implications of such modifications in cellular functions and related diseases and their importance for targeted treatment strategies.
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Affiliation(s)
- Andrea Olschewski
- 1 Ludwig Boltzmann Institute for Lung Vascular Research , Graz, Austria
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18
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Gennai S, Pison C, Briot R. [Ischemia-reperfusion injury after lung transplantation]. Presse Med 2014; 43:921-30. [PMID: 24935680 DOI: 10.1016/j.lpm.2014.01.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 12/17/2013] [Accepted: 01/06/2014] [Indexed: 10/25/2022] Open
Abstract
Lung ischemia-reperfusion is characterized by diffuse alveolar damage arising from the first hours after transplantation. The first etiology of the primary graft dysfunction in lung is ischemia-reperfusion. It is burdened by an important morbi-mortality. Lung ischemia-reperfusion increases the oxidative stress, inactivates the sodium pump, increases the intracellular calcium, leads to cellular death and the liberation of pro-inflammatory mediators. Researches relative to the reduction of the lung ischemia-reperfusion injuries are numerous but few of them found a place in common clinical practice, because of an insufficient level of proofs. Ex vivolung evaluation is a suitable technique in order to evaluate therapeutics supposed to limit lung ischemia-reperfusion injuries.
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Affiliation(s)
- Stéphane Gennai
- CHU de Grenoble, pôle urgences et médecine aiguë, CS 10217, 38043 Grenoble cedex 09, France; Laboratoire TIMC-IMAG, UMR 5525, domaine de la Merci, 38706 La Tronche cedex, France.
| | - Christophe Pison
- Université Joseph-Fourier, laboratoire de bioénergétique fondamentale et appliquée, Inserm U1055, BP 53, 38041 Grenoble cedex 09, France
| | - Raphaël Briot
- CHU de Grenoble, pôle urgences et médecine aiguë, CS 10217, 38043 Grenoble cedex 09, France; Laboratoire TIMC-IMAG, UMR 5525, domaine de la Merci, 38706 La Tronche cedex, France
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19
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Kuriyama S, Morio Y, Toba M, Nagaoka T, Takahashi F, Iwakami SI, Seyama K, Takahashi K. Genistein attenuates hypoxic pulmonary hypertension via enhanced nitric oxide signaling and the erythropoietin system. Am J Physiol Lung Cell Mol Physiol 2014; 306:L996-L1005. [PMID: 24705719 DOI: 10.1152/ajplung.00276.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Upregulation of the erythropoietin (EPO)/EPO receptor (EPOR) system plays a protective role against chronic hypoxia-induced pulmonary hypertension (hypoxic PH) through enhancement of endothelial nitric oxide (NO)-mediated signaling. Genistein (Gen), a phytoestrogen, is considered to ameliorate NO-mediated signaling. We hypothesized that Gen attenuates and prevents hypoxic PH. In vivo, Sprague-Dawley rats raised in a hypobaric chamber were treated with Gen (60 mkg/kg) for 21 days. Pulmonary hemodynamics and vascular remodeling were ameliorated in Gen-treated hypoxic PH rats. Gen also restored cGMP levels and phosphorylated endothelial NO synthase (p-eNOS) at Ser(1177) and p-Akt at Ser(473) expression in the lungs. Additionally, Gen potentiated plasma EPO concentration and EPOR-positive endothelial cell counts. In experiments with hypoxic PH rats' isolated perfused lungs, Gen caused NO- and phosphatidylinositol 3-kinase (PI3K)/Akt-dependent vasodilation that reversed abnormal vasoconstriction. In vitro, a combination of EPO and Gen increased the p-eNOS and the EPOR expression in human umbilical vein endothelial cells under a hypoxic environment. Moreover, Gen potentiated the hypoxic increase in EPO production from human hepatoma cells. We conclude that Gen may be effective for the prevention of hypoxic PH through the improvement of PI3K/Akt-dependent, NO-mediated signaling in association with enhancement of the EPO/EPOR system.
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Affiliation(s)
- Sachiko Kuriyama
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yoshiteru Morio
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Michie Toba
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tetsutaro Nagaoka
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Fumiyuki Takahashi
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shin-Ichiro Iwakami
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kuniaki Seyama
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Kazuhisa Takahashi
- Department of Respiratory Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
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20
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Xie L, Zhang X, Qi D, Guo X, Pang B, Du Y, Zou X, Guo S, Zhao X. Inhibition of inducible nitric oxide synthase expression and nitric oxide production in plateau pika (Ochotona curzoniae) at high altitude on Qinghai-Tibet Plateau. Nitric Oxide 2014; 38:38-44. [DOI: 10.1016/j.niox.2014.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Revised: 02/19/2014] [Accepted: 02/27/2014] [Indexed: 12/28/2022]
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21
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Nuñez C, Victor VM, Martí M, D'Ocon P. Role of endothelial nitric oxide in pulmonary and systemic arteries during hypoxia. Nitric Oxide 2013; 37:17-27. [PMID: 24365975 DOI: 10.1016/j.niox.2013.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 11/12/2013] [Accepted: 12/12/2013] [Indexed: 10/25/2022]
Abstract
UNLABELLED Our aim was to investigate the role played by endothelial nitric oxide (NO) during acute vascular response to hypoxia, as a modulator of both vascular tone (through guanylate cyclase (sGC) activation) and mitochondrial O2 consumption (through competitive inhibition of cytochrome-c-oxydase (CcO)). Organ bath experiments were performed and O2 consumption (Clark electrode) was determined in isolated aorta, mesenteric and pulmonary arteries of rats and eNOS-knockout mice. All pre-contracted vessels exhibited a triphasic hypoxic response consisting of an initial transient contraction (not observed in vessels from eNOS-knockout mice) followed by relaxation and subsequent sustained contraction. Removal of the endothelium, inhibition of eNOS (by L-NNA) and inhibition of sGC (by ODQ) abolished the initial contraction without altering the other two phases. The initial hypoxic contraction was observed in the presence of L-NNA+NO-donors. L-NNA and ODQ increases O2 consumption in hypoxic vessels and increases the arterial tone in normoxia but not in hypoxia. When L-NNA+mitochondrial inhibitors (cyanide, rotenone or myxothiazol) were added, the increase in tone was similar in normoxic and hypoxic vessels, which suggests that inhibition of the binding of NO to reduced CcO restored the action of NO on sGC. CONCLUSION A complex equilibrium is established between NO, sGC and CcO in vessels in function of the concentration of O2: as O2 falls, NO inhibition of mitochondrial O2 consumption increases and activation of sGC decreases, thus promoting a rapid increase in tone in both pulmonary and systemic vessels, which is followed by the triggering of NO-independent vasodilator/vasoconstrictor mechanisms.
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Affiliation(s)
- Cristina Nuñez
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Spain
| | - Victor M Victor
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Spain; FISABIO-Hospital Universitario Doctor Peset, Av. Gaspar Aguilar 90, 46017 Valencia, Spain; Department of Physiology, University of Valencia, Valencia, Spain
| | - Miguel Martí
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Spain
| | - Pilar D'Ocon
- Departamento de Farmacología and CIBERehd, Facultad de Medicina, Universidad de Valencia, Spain.
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22
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Tajsic T, Morrell NW. Smooth muscle cell hypertrophy, proliferation, migration and apoptosis in pulmonary hypertension. Compr Physiol 2013; 1:295-317. [PMID: 23737174 DOI: 10.1002/cphy.c100026] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pulmonary hypertension is a multifactorial disease characterized by sustained elevation of pulmonary vascular resistance (PVR) and pulmonary arterial pressure (PAP). Central to the pathobiology of this disease is the process of vascular remodelling. This process involves structural and functional changes to the normal architecture of the walls of pulmonary arteries (PAs) that lead to increased muscularization of the muscular PAs, muscularization of the peripheral, previously nonmuscular, arteries of the respiratory acinus, formation of neointima, and formation of plexiform lesions. Underlying or contributing to the development of these lesions is hypertrophy, proliferation, migration, and resistance to apoptosis of medial cells and this article is concerned with the cellular and molecular mechanisms of these processes. In the first part of the article we focus on the concept of smooth muscle cell phenotype and the difficulties surrounding the identification and characterization of the cell/cells involved in the remodelling of the vessel media and we review the general mechanisms of cell hypertrophy, proliferation, migration and apoptosis. Then, in the larger part of the article, we review the factors identified thus far to be involved in PH intiation and/or progression and review and discuss their effects on pulmonary artery smooth muscle cells (PASMCs) the predominant cells in the tunica media of PAs.
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Affiliation(s)
- Tamara Tajsic
- Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
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23
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Bakr A, Pak O, Taye A, Hamada F, Hemeida R, Janssen W, Gierhardt M, Ghofrani HA, Seeger W, Grimminger F, Schermuly RT, Witzenrath M, Brandes RP, Huang N, Cooke JP, Weissmann N, Sommer N. Effects of dimethylarginine dimethylaminohydrolase-1 overexpression on the response of the pulmonary vasculature to hypoxia. Am J Respir Cell Mol Biol 2013; 49:491-500. [PMID: 23642043 DOI: 10.1165/rcmb.2012-0330oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Acute and sustained hypoxic pulmonary vasoconstriction (HPV), as well as chronic pulmonary hypertension (PH), is modulated by nitric oxide (NO). NO synthesis can be decreased by asymmetric dimethylarginine (ADMA), which is degraded by dimethylarginine dimethylaminohydrolase-1 (DDAH1). We investigated the effects of DDAH1 overexpression (DDAH1(tg)) on HPV and chronic hypoxia-induced PH. HPV was measured during acute (10 min) and sustained (3 h) hypoxia in isolated mouse lungs. Chronic PH was induced by the exposure of mice to 4 weeks of hypoxia. ADMA and cyclic 3',5'-guanosine monophosphate (cGMP) were determined by ELISA, and NO generation was determined by chemiluminescence. DDAH1 overexpression exerted no effects on acute HPV. However, DDAH1(tg) mice showed decreased sustained HPV compared with wild-type (WT) mice. Concomitantly, ADMA was decreased, and concentrations of NO and cGMP were significantly increased in DDAH1(tg). The administration of either Nω-nitro-l-arginine or 1H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one potentiated sustained HPV and partly abolished the differences in sustained HPV between WT and DDAH1(tg) mice. The overexpression of DDAH1 exerted no effect on the development of chronic hypoxia-induced PH. DDAH1 overexpression selectively decreased the sustained phase of HPV, partly via activation of the NO-cGMP pathway. Thus, increased ADMA concentrations modulate sustained HPV, but not acute HPV or chronic hypoxia-induced PH.
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Affiliation(s)
- Adel Bakr
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
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24
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Castiglione N, Rinaldo S, Giardina G, Stelitano V, Cutruzzolà F. Nitrite and nitrite reductases: from molecular mechanisms to significance in human health and disease. Antioxid Redox Signal 2012; 17:684-716. [PMID: 22304560 DOI: 10.1089/ars.2011.4196] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Nitrite, previously considered physiologically irrelevant and a simple end product of endogenous nitric oxide (NO) metabolism, is now envisaged as a reservoir of NO to be activated in response to oxygen (O(2)) depletion. In the first part of this review, we summarize and compare the mechanisms of nitrite-dependent production of NO in selected bacteria and in eukaryotes. Bacterial nitrite reductases, which are copper or heme-containing enzymes, play an important role in the adaptation of pathogens to O(2) limitation and enable microrganisms to survive in the human body. In mammals, reduction of nitrite to NO under hypoxic conditions is carried out in tissues and blood by an array of metalloproteins, including heme-containing proteins and molybdenum enzymes. In humans, tissues play a more important role in nitrite reduction, not only because most tissues produce more NO than blood, but also because deoxyhemoglobin efficiently scavenges NO in blood. In the second part of the review, we outline the significance of nitrite in human health and disease and describe the recent advances and pitfalls of nitrite-based therapy, with special attention to its application in cardiovascular disorders, inflammation, and anti-bacterial defence. It can be concluded that nitrite (as well as nitrate-rich diet for long-term applications) may hold promise as therapeutic agent in vascular dysfunction and ischemic injury, as well as an effective compound able to promote angiogenesis.
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Affiliation(s)
- Nicoletta Castiglione
- Department of Biochemical Sciences, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
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25
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Mihaylova S, Killian A, Mayer K, Pullamsetti SS, Schermuly R, Rosengarten B. Effects of anti-inflammatory vagus nerve stimulation on the cerebral microcirculation in endotoxinemic rats. J Neuroinflammation 2012; 9:183. [PMID: 22830560 PMCID: PMC3425315 DOI: 10.1186/1742-2094-9-183] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 06/25/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In sepsis syndromes the severity of the inflammation triggers microvascular dysfunction and early organ failure. We studied the effects of anti-inflammatory vagus nerve stimulation on the cerebral microcirculatory integrity in an endotoxinemic rat model. METHODS In both control and endotoxinemic (5 mg/kg lipopolysaccharide i.v.) rats, the effect of cervical bilateral vagotomy with or without left-sided distal vagus nerve stimulation were compared to non-vagotomized, nonstimulated group (sham). Neurovascular coupling was analyzed by electrical forepaw stimulation, EEG, and cortical laser-Doppler flow recording. Resting cerebral blood flow, evoked potentials and hemodynamic responses, were obtained over a period of 4.5 hours. Regulation of the nitric oxide system (iNOS expression and nitrite/nitrate measurements), cytokines (IFN-γ, TNF-α, IL-6, IL-10), hypoxic and apoptosis signaling molecules (HIF-2α, Bax) were measured at the end of experiments. RESULTS In endotoxinemic rats, vagus nerve stimulation tended to increase anti-inflammatory cytokine levels and resulted in a stabile hemodynamic response (28 ± 13%; versus baseline). Vagotomized animals incurred a pro-inflammatory response (7 ± 4%; P < 0.0001 versus baseline) and produced more HIF-2α than vagotomized vagus nerve stimulated (VNS) animals. Evoked potential amplitudes were stabilized in VNS (15 ± 7 μV; n.s. versus baseline) as compared to vagotomised rats (8 ± 5 μV; P < 0.001 versus baseline). However, no effects were observed on apoptosis markers or nitric oxide levels. CONCLUSIONS Vagus nerve stimulation in endotoxinemic rats had a positive effect on neurovascular coupling and stabilized evoked potentials.
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Affiliation(s)
- Stanka Mihaylova
- Department of Neurology, Justus Liebig University, Klinikstrasse 33, D-35392, Giessen, Germany
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26
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Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
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Affiliation(s)
- J T Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School ofMedicine, Baltimore, Maryland, USA.
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27
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Exogenous ghrelin improves blood flow distribution in pulmonary hypertension-assessed using synchrotron radiation microangiography. Pflugers Arch 2011; 462:397-406. [PMID: 21744075 DOI: 10.1007/s00424-011-0992-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 06/09/2011] [Accepted: 06/23/2011] [Indexed: 10/18/2022]
Abstract
Ghrelin has cardioprotective properties and, recently, has been shown to improve endothelial function and reduce endothelin-1 (ET-1)-mediated vasoconstriction in peripheral vascular disease. Recently, we reported that ghrelin attenuates pulmonary hypertension (PH) caused by chronic hypoxia (CH), which we hypothesized in this study may be via suppression of the ET-1 pathway. We also aimed to determine whether ghrelin's ability to prevent alterations of the ET-1 pathway also prevented adverse changes in pulmonary blood flow distribution associated with PH. Sprague-Dawley rats were exposed to CH (10% O(2) for 2 weeks) with daily subcutaneous injections of ghrelin (150 μg/kg) or saline. Utilizing synchrotron radiation microangiography, we assessed pulmonary vessel branching structure, which is indicative of blood flow distribution, and dynamic changes in vascular responsiveness to (1) ET-1 (1 nmol/kg), (2) the ET-1(A) receptor antagonist, BQ-123 (1 mg/kg), and (3) ACh (3.0 μg kg⁻¹ min⁻¹). CH impaired blood flow distribution throughout the lung. However, this vessel "rarefaction" was attenuated in ghrelin-treated CH-rats. Moreover, ghrelin (1) reduced the magnitude of endothelial dysfunction, (2) prevented an increase in ET-1-mediated vasoconstriction, and (3) reduced pulmonary vascular remodeling and right ventricular hypertrophy-all adverse consequences associated with CH. These results highlight the beneficial effects of ghrelin for maintaining optimal lung perfusion in the face of a hypoxic insult. Further research is now required to establish whether ghrelin is also an effective therapy for restoring normal pulmonary hemodynamics in patients that already have established PH.
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28
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Jun N, Ke J, Gang C, Lin C, Jinsong L, Jianjun W. The Protective Effect of Ischemic Preconditioning Associated with Altered Gene Expression Profiles in Rat Lung after Reperfusion. J Surg Res 2011; 168:281-93. [DOI: 10.1016/j.jss.2009.10.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 09/30/2009] [Accepted: 10/14/2009] [Indexed: 11/26/2022]
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Rus A, Del Moral ML, Molina F, Peinado MA. Upregulation of cardiac NO/NOS system during short-term hypoxia and the subsequent reoxygenation period. Eur J Histochem 2011; 55:e17. [PMID: 22193297 PMCID: PMC3284153 DOI: 10.4081/ejh.2011.e17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 04/06/2011] [Accepted: 04/08/2011] [Indexed: 01/05/2023] Open
Abstract
Hypoxia/reoxygenation (H/R) reportedly influences nitric oxide (NO) production and NO synthase (NOS) expression in the heart. Nonetheless, a number of works have shown controversial results regarding the changes that the cardiac NO/NOS system undergoes under such situations. Therefore, this study aims to clarify the behaviour of this system in the hypoxic heart by investigating seven different reoxygenation times. Wistar rats were submitted to H/R (hypoxia for 30 min; reoxygenation of 0, 2, 12, 24, 48, 72 h, and 5 days) in a novel approach to address the events provoked by assaults under such circumstances. Endothelial and inducible NOS (eNOS and iNOS) mRNA and protein expression, as well as enzymatic activity and enzyme location were determined. NO levels were indirectly quantified as nitrate/nitrite, and other S-nitroso compounds (NOx), which would act as NO-storage molecules. The results showed a significant increase in eNOS mRNA, protein and activity, as well as in NOx levels immediately after hypoxia, while iNOS protein and activity were induced throughout the reoxygenation period. These findings indicate that, not only short-term hypoxia, but also the subsequent reoxygenation period upregulate cardiac NO/NOS system until at least 5 days after the hypoxic stimulus, implying major involvement of this system in the changes occurring in the heart in response to H/R.
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Affiliation(s)
- A Rus
- Department of Experimental Biology (Building B-3), University of Jaén,Campus Las Lagunillas s/n, 23071 Jaén, Spain.
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30
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Abstract
Most current theories for the mechanism of hypoxic pulmonary vasoconstriction (HPV) include a role for reactive oxygen species and/or changes in redox regulation, but extreme controversy exists regarding which systems and redox changes mediate the HPV response. Nitric oxide (NO) appears to help to maintain low pulmonary arterial pressure, suppress HPV, and prevent the development of pulmonary hypertension. Our studies have found a key role for glucose-6-phosphate dehydrogenase in bovine pulmonary arterial smooth muscle functioning to maintain elevated levels of cytosolic NADPH which fuels the generation of vasodilator levels of hydrogen peroxide. HPV results from hypoxia removing vasodilation by peroxide. Decreased superoxide generation by Nox4 oxidase and its conversion to peroxide by Cu,Zn-SOD appear to be potential factors in sensing hypoxia, and decreased cGMP-associated vasodilation and removal of redox controlled vasodilator mechanisms by increased cytosolic NADPH may be key coordinators of the HPV response. Oxidant generation associated with vascular disease processes, including the removal of NO by superoxide, and attenuation of its ability to stimulate cGMP production by oxidation of the heme and thiols of soluble guanylate cyclase attenuate potential beneficial actions of NO on pulmonary arterial function. While pulmonary hypertension appears to have multiple poorly understood effects on redox-associated processes, potentially influencing responses to hypoxia and NO-cGMP signaling, much remains to be elucidated regarding how these processes may be important factors in the progression, expression and therapeutic treatment of pulmonary hypertension.
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Koo HS, Kim KC, Hong YM. Gene expressions of nitric oxide synthase and matrix metalloproteinase-2 in monocrotaline-induced pulmonary hypertension in rats after bosentan treatment. Korean Circ J 2011; 41:83-90. [PMID: 21430993 PMCID: PMC3053565 DOI: 10.4070/kcj.2011.41.2.83] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 07/21/2010] [Indexed: 11/30/2022] Open
Abstract
Background and Objectives Nitric oxide (NO) is a major endothelium dependent vasomediator and growth inhibitor. NO synthesis is catalyzed by endothelial nitric oxide synthase (eNOS), and NO can also produce peroxynitrite, which activates matrix metalloproteinases (MMPs). The purpose of this study was to determine the gene expression of eNOS and MMP-2 in the lungs of a rat model of pulmonary hypertension after bosentan treatment. Materials and Methods Six-week-old male Sprague-Dawley rats were treated as follows: control group, subcutaneous (sc) injection of saline; monocrotaline (MCT) group, sc injection of MCT (60 mg/kg); and bosentan group, sc injection of MCT (60 mg/kg) plus 20 mg/day bosentan orally. The rats were sacrificed after 1, 5, 7, 14 and 28 days. Results The right ventricle/(left ventricle+septum) ratio significantly increased in the MCT group compared to the control group on day 14 and 28. The expression of eNOS messenger ribonucleic acid was significantly increased in the MCT group compared to the control group on day 28. MMP-2 gene expression was significantly increased in the MCT-treated rats compared to the control group on day 5 and 28. Following bosentan treatment to reduce pulmonary hypertension, the expression levels of MMP-2 gene were significantly decreased on day 7 and 28. eNOS and tissue inhibitor of MMPs genes were also significantly decreased on day 28 after bosentan treatment. Conclusion These results suggest that elevated eNOS expression may be responsible for MMP-2 activation. The causal relationship between eNOS and MMP-2 and their role in pulmonary hypertension require further investigations.
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Affiliation(s)
- Hee Sun Koo
- Department of Pediatrics, School of Medicine, Ewha Womans University, Seoul, Korea
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Vinnikov D, Brimkulov N, Redding-Jones R, Jumabaeva K. Exhaled nitric oxide is reduced upon chronic intermittent hypoxia exposure in well-acclimatized mine workers. Respir Physiol Neurobiol 2011; 175:261-4. [DOI: 10.1016/j.resp.2010.11.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 10/18/2022]
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Abstract
During the development of the pulmonary vasculature in the fetus, many structural and functional changes occur to prepare the lung for the transition to air breathing. The development of the pulmonary circulation is genetically controlled by an array of mitogenic factors in a temporo-spatial order. With advancing gestation, pulmonary vessels acquire increased vasoreactivity. The fetal pulmonary vasculature is exposed to a low oxygen tension environment that promotes high intrinsic myogenic tone and high vasocontractility. At birth, a dramatic reduction in pulmonary arterial pressure and resistance occurs with an increase in oxygen tension and blood flow. The striking hemodynamic differences in the pulmonary circulation of the fetus and newborn are regulated by various factors and vasoactive agents. Among them, nitric oxide, endothelin-1, and prostaglandin I2 are mainly derived from endothelial cells and exert their effects via cGMP, cAMP, and Rho kinase signaling pathways. Alterations in these signaling pathways may lead to vascular remodeling, high vasocontractility, and persistent pulmonary hypertension of the newborn.
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Affiliation(s)
- Yuansheng Gao
- Department of Physiology and Pathophysiology, Peking University, Health Science Center, Beijing, China; and Department of Pediatrics, University of Illinois, College of Medicine at Chicago, Chicago, Illinois
| | - J. Usha Raj
- Department of Physiology and Pathophysiology, Peking University, Health Science Center, Beijing, China; and Department of Pediatrics, University of Illinois, College of Medicine at Chicago, Chicago, Illinois
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Bailey DM, Dehnert C, Luks AM, Menold E, Castell C, Schendler G, Faoro V, Gutowski M, Evans KA, Taudorf S, James PE, McEneny J, Young IS, Swenson ER, Mairbäurl H, Bärtsch P, Berger MM. High-altitude pulmonary hypertension is associated with a free radical-mediated reduction in pulmonary nitric oxide bioavailability. J Physiol 2010; 588:4837-47. [PMID: 20876202 DOI: 10.1113/jphysiol.2010.194704] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
High altitude (HA)-induced pulmonary hypertension may be due to a free radical-mediated reduction in pulmonary nitric oxide (NO) bioavailability. We hypothesised that the increase in pulmonary artery systolic pressure (PASP) at HA would be associated with a net transpulmonary output of free radicals and corresponding loss of bioactive NO metabolites. Twenty-six mountaineers provided central venous and radial arterial samples at low altitude (LA) and following active ascent to 4559 m (HA). PASP was determined by Doppler echocardiography, pulmonary blood flow by inert gas re-breathing, and vasoactive exchange via the Fick principle. Acute mountain sickness (AMS) and high-altitude pulmonary oedema (HAPE) were diagnosed using clinical questionnaires and chest radiography. Electron paramagnetic resonance spectroscopy, ozone-based chemiluminescence and ELISA were employed for plasma detection of the ascorbate free radical (A(·-)), NO metabolites and 3-nitrotyrosine (3-NT). Fourteen subjects were diagnosed with AMS and three of four HAPE-susceptible subjects developed HAPE. Ascent decreased the arterio-central venous concentration difference (a-cv(D)) resulting in a net transpulmonary loss of ascorbate, α-tocopherol and bioactive NO metabolites (P < 0.05 vs. LA). This was accompanied by an increased a-cv(D) and net output of A(·-) and lipid hydroperoxides (P < 0.05 vs. sea level, SL) that correlated against the rise in PASP (r = 0.56-0.62, P < 0.05) and arterial 3-NT (r = 0.48-0.63, P < 0.05) that was more pronounced in HAPE. These findings suggest that increased PASP and vascular resistance observed at HA are associated with a free radical-mediated reduction in pulmonary NO bioavailability.
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Affiliation(s)
- Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Health, Science and Sport, University of Glamorgan, South Wales, UK.
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Wolin MS, Gupte SA, Mingone CJ, Neo BH, Gao Q, Ahmad M. Redox regulation of responses to hypoxia and NO-cGMP signaling in pulmonary vascular pathophysiology. Ann N Y Acad Sci 2010; 1203:126-32. [PMID: 20716294 DOI: 10.1111/j.1749-6632.2010.05557.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pulmonary vascular responses elicited by hypoxia and NO-cGMP signaling are potentially influenced by ROS and redox mechanisms that change during the progression of disease processes. Our studies in endothelium-rubbed bovine pulmonary arteries suggest increased glucose-6-phosphate dehydrogenase levels (compared to coronary arteries) seem to maintain a tonic peroxide-mediated relaxation removed by hypoxia through NADPH fueling superoxide generation from Nox oxidase. The activities of glucose-6-phosphate dehydrogenase, oxidases (i.e., Nox4), and systems metabolizing superoxide and peroxide markedly influence hypoxic pulmonary vasoconstriction (HPV). Activation of soluble guanylate cyclase and cGMP protein kinase seems to participate in peroxide-elicited relaxation. Endogenous NO helps maintain low pulmonary arterial pressure and suppresses HPV. Multiple redox processes potentially occurring during the progression of pulmonary hypertension may also attenuate NO-mediated relaxation beyond its scavenging by superoxide, including oxidation of guanylate cyclase heme and thiols normally maintained by cytosolic NADPH redox control.
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Affiliation(s)
- Michael S Wolin
- Department of Physiology and Pulmonary Hypertension Center, New York Medical College, Valhalla, New York, USA.
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Kajimura M, Fukuda R, Bateman RM, Yamamoto T, Suematsu M. Interactions of multiple gas-transducing systems: hallmarks and uncertainties of CO, NO, and H2S gas biology. Antioxid Redox Signal 2010; 13:157-92. [PMID: 19939208 PMCID: PMC2925289 DOI: 10.1089/ars.2009.2657] [Citation(s) in RCA: 219] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The diverse physiological actions of the "biologic gases," O2, CO, NO, and H2S, have attracted much interest. Initially viewed as toxic substances, CO, NO, and H2S play important roles as signaling molecules. The multiplicity of gas actions and gas targets and the difficulty in measuring local gas concentrations obscures detailed mechanisms whereby gases exert their actions, and many questions remain unanswered. It is now readily apparent, however, that heme-based proteins play central roles in gas-generation/reception mechanisms and provide a point where multiple gases can interact. In this review, we consider a number of key issues related to "gas biology," including the effective tissue concentrations of these gases and the importance and significance of the physical proximity of gas-producing and gas-receptor/sensors. We also take an integrated approach to the interaction of gases by considering the physiological significance of CO, NO, and H2S on mitochondrial cytochrome c oxidase, a key target and central mediator of mitochondrial respiration. Additionally, we consider the effects of biologic gases on mitochondrial biogenesis and "suspended animation." By evaluating gas-mediated control functions from both in vitro and in vivo perspectives, we hope to elaborate on the complex multiple interactions of O2, NO, CO, and H2S.
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Affiliation(s)
- Mayumi Kajimura
- Department of Biochemistry and Integrative Medical Biology, School of Medicine, Keio University , Tokyo, Japan.
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Wang P, Ha AY, Kidd KK, Koehle MS, Rupert JL. A Variant of the Endothelial Nitric Oxide Synthase Gene (NOS3) Associated with AMS Susceptibility Is Less Common in the Quechua, a High Altitude Native Population. High Alt Med Biol 2010; 11:27-30. [DOI: 10.1089/ham.2009.1054] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Pei Wang
- School of Human Kinetics, University of British Columbia, Vancouver, BC, Canada
| | - Alice Y.N. Ha
- Department of Biochemistry, University of British Columbia, Vancouver, BC, Canada
| | - Kenneth K. Kidd
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Michael S. Koehle
- School of Human Kinetics, University of British Columbia, Vancouver, BC, Canada
- Allan McGavin Sport Medicine Centre, Department of Family Practice, University of British Columbia, Vancouver, BC, Canada
| | - Jim L. Rupert
- School of Human Kinetics, University of British Columbia, Vancouver, BC, Canada
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Kondrikov D, Fonseca FV, Elms S, Fulton D, Black SM, Block ER, Su Y. Beta-actin association with endothelial nitric-oxide synthase modulates nitric oxide and superoxide generation from the enzyme. J Biol Chem 2010; 285:4319-27. [PMID: 19946124 PMCID: PMC2836036 DOI: 10.1074/jbc.m109.063172] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 11/20/2009] [Indexed: 11/06/2022] Open
Abstract
Protein-protein interactions represent an important post-translational mechanism for endothelial nitric-oxide synthase (eNOS) regulation. We have previously reported that beta-actin is associated with eNOS oxygenase domain and that association of eNOS with beta-actin increases eNOS activity and nitric oxide (NO) production. In the present study, we found that beta-actin-induced increase in NO production was accompanied by decrease in superoxide formation. A synthetic actin-binding sequence (ABS) peptide 326 with amino acid sequence corresponding to residues 326-333 of human eNOS, one of the putative ABSs, specifically bound to beta-actin and prevented eNOS association with beta-actin in vitro. Peptide 326 also prevented beta-actin-induced decrease in superoxide formation and increase in NO and L-citrulline production. A modified peptide 326 replacing hydrophobic amino acids leucine and tryptophan with neutral alanine was unable to interfere with eNOS-beta-actin binding and to prevent beta-actin-induced changes in NO and superoxide formation. Site-directed mutagenesis of the actin-binding domain of eNOS replacing leucine and tryptophan with alanine yielded an eNOS mutant that exhibited reduced eNOS-beta-actin association, decreased NO production, and increased superoxide formation in COS-7 cells. Disruption of eNOS-beta-actin interaction in endothelial cells using ABS peptide 326 resulted in decreased NO production, increased superoxide formation, and decreased endothelial monolayer wound repair, which was prevented by PEG-SOD and NO donor NOC-18. Taken together, this novel finding indicates that beta-actin binding to eNOS through residues 326-333 in the eNOS protein results in shifting the enzymatic activity from superoxide formation toward NO production. Modulation of NO and superoxide formation from eNOS by beta-actin plays an important role in endothelial function.
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Affiliation(s)
| | | | | | - David Fulton
- From the Department of Pharmacology and Toxicology
- Vascular Biology Center, and
| | | | - Edward R. Block
- the Department of Medicine, University of Florida College of Medicine, Gainesville, Florida 32610
| | - Yunchao Su
- From the Department of Pharmacology and Toxicology
- Department of Medicine
- Vascular Biology Center, and
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta, Georgia 30912 and
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Lee TF, Tymafichuk CN, Schulz R, Cheung PY. Post-resuscitation NOS inhibition does not improve hemodynamic recovery of hypoxic newborn pigs. Intensive Care Med 2009; 35:1628-35. [PMID: 19551371 DOI: 10.1007/s00134-009-1553-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 03/31/2009] [Indexed: 12/01/2022]
Abstract
BACKGROUND Significant improvement in myocardial recovery has been shown previously with interventions to decrease reactive oxygen species after ischemia/hypoxia. We investigated whether co-administration of N-acetylcysteine (NAC, a scavenger for reactive oxygen species) and N (G)-monomethyl-L: -arginine (L-NMMA, a non-selective nitric oxide synthase inhibitor) results in better hemodynamic recovery. DESIGN Controlled, block-randomized study. SETTING University research laboratory. SUBJECT Mixed breed piglets (1-4d, 1.6-2.4 kg). INTERVENTIONS Acutely instrumented piglets received normocapnic alveolar hypoxia (10-15% oxygen) for 2 h followed by reoxygenation with 100% oxygen (1 h) then 21% oxygen (3 h). After reoxygenation, hypoxic-reoxygenated piglets were given either saline (controls), NAC [30 mg/kg bolus + 20 mg/(kg h) infusion], NMMA [0.1 mg/kg bolus + 0.1 mg/(kg h) infusion] or NAC + L-NMMA via intravenous infusion in a blinded, randomized fashion (n = 8/group). Sham-operated piglets had no hypoxia-reoxygenation (n = 5). MEASUREMENTS AND RESULTS Both cardiac index and stroke volume of hypoxia-reoxygenation controls remained depressed during reoxygenation (vs. normoxic baseline, p < 0.05). Post-resuscitation treatment with L-NMMA alone did not improve systemic hemodynamic recovery, but caused pulmonary hypertension (vs. controls). In contrast, treating the piglets with either NAC or NAC + L-NMMA improved cardiac index and stroke volume, with no effect on heart rate and blood pressure (vs. controls). These treatments also decreased various oxidative stress markers in myocardial tissues (vs. controls). However, there was no significant difference between NAC- and NAC + L-NMMA groups in all examined parameters. CONCLUSIONS Post-resuscitation administration of NAC improved cardiac function and reduced oxidative stress in newborn pigs with hypoxia-reoxygenation insult. Low-dose, non-selective inhibitor of nitric oxide synthase activity did not provide any further beneficial effect.
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Affiliation(s)
- Tze-fun Lee
- Department of Pediatrics, University of Alberta, NICU Royal Alexandra Hospital, Edmonton, Alberta T5H 3V9, Canada
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40
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Bernal PJ, Leelavanichkul K, Bauer E, Cao R, Wilson A, Wasserloos KJ, Watkins SC, Pitt BR, St Croix CM. Nitric-oxide-mediated zinc release contributes to hypoxic regulation of pulmonary vascular tone. Circ Res 2008; 102:1575-83. [PMID: 18483408 DOI: 10.1161/circresaha.108.171264] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The metal binding protein metallothionein (MT) is a target for nitric oxide (NO), causing release of bound zinc that affects myogenic reflex in systemic resistance vessels. Here, we investigate a role for NO-induced zinc release in pulmonary vasoregulation. We show that acute hypoxia causes reversible constriction of intraacinar arteries (<50 microm/L) in isolated perfused mouse lung (IPL). We further demonstrate that isolated pulmonary (but not aortic) endothelial cells constrict in hypoxia. Hypoxia also causes NO-dependent increases in labile zinc in mouse lung endothelial cells and endothelium of IPL. The latter observation is dependent on MT because it is not apparent in IPL of MT(-/-) mice. Data from NO-sensitive fluorescence resonance energy transfer-based reporters support hypoxia-induced NO production in pulmonary endothelium. Furthermore, hypoxic constriction is blunted in IPL of MT(-/-) mice and in wild-type mice, or rats, treated with the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)-ethylenediamine (TPEN), suggesting a role for chelatable zinc in modulating HPV. Finally, the NO donor DETAnonoate causes further vasoconstriction in hypoxic IPL in which NO vasodilatory pathways are inhibited. Collectively, these data suggest that zinc thiolate signaling is a component of the effects of acute hypoxia-mediated NO biosynthesis and that this pathway may contribute to constriction in the pulmonary vasculature.
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Affiliation(s)
- Paula J Bernal
- Center for Biological Imaging, Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA 15219, USA
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42
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Peyter AC, Muehlethaler V, Liaudet L, Marino M, Di Bernardo S, Diaceri G, Tolsa JF. Muscarinic receptor M1 and phosphodiesterase 1 are key determinants in pulmonary vascular dysfunction following perinatal hypoxia in mice. Am J Physiol Lung Cell Mol Physiol 2008; 295:L201-13. [PMID: 18469116 DOI: 10.1152/ajplung.00264.2007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Perinatal adverse events such as limitation of nutrients or oxygen supply are associated with the occurrence of diseases in adulthood, like cardiovascular diseases and diabetes. We investigated the long-term effects of perinatal hypoxia on the lung circulation, with particular attention to the nitric oxide (NO)/cGMP pathway. Mice were placed under hypoxia in utero 5 days before delivery and for 5 days after birth. Pups were then bred in normoxia until adulthood. Adults born in hypoxia displayed an altered regulation of pulmonary vascular tone with higher right ventricular pressure in normoxia and increased sensitivity to acute hypoxia compared with controls. Perinatal hypoxia dramatically decreased endothelium-dependent relaxation induced by ACh in adult pulmonary arteries (PAs) but did not influence NO-mediated endothelium-independent relaxation. The M(3) muscarinic receptor was implicated in the relaxing action of ACh and M(1) muscarinic receptor (M(1)AChR) in its vasoconstrictive effects. Pirenzepine or telenzepine, two preferential inhibitors of M(1)AChR, abolished the adverse effects of perinatal hypoxia on ACh-induced relaxation. M(1)AChR mRNA expression was increased in lungs and PAs of mice born in hypoxia. The phosphodiesterase 1 (PDE1) inhibitor vinpocetine also reversed the decrease in ACh-induced relaxation following perinatal hypoxia, suggesting that M(1)AChR-mediated alteration of ACh-induced relaxation is due to the activation of calcium-dependent PDE1. Therefore, perinatal hypoxia leads to an altered pulmonary circulation in adulthood with vascular dysfunction characterized by impaired endothelium-dependent relaxation and M(1)AChR plays a predominant role. This raises the possibility that muscarinic receptors could be key determinants in pulmonary vascular diseases in relation to "perinatal imprinting."
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Affiliation(s)
- Anne-Christine Peyter
- Neonatal Research Laboratory, Department of Pediatrics, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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43
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Herrera EA, Ebensperger G, Krause BJ, Riquelme RA, Reyes RV, Capetillo M, González S, Parer JT, Llanos AJ. Sildenafil reverses hypoxic pulmonary hypertension in highland and lowland newborn sheep. Pediatr Res 2008; 63:169-75. [PMID: 18091352 DOI: 10.1203/pdr.0b013e31815ef71c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Perinatal exposure to chronic hypoxia induces sustained hypertension and structural and functional changes in the pulmonary vascular bed. We hypothesized that highland newborn lambs (HLNB, 3600 m) have a higher pulmonary arterial pressure (PAP) due in part to a higher activity/expression of phosphodiesterase 5 (PDE5). We administered sildenafil, a PDE5 inhibitor, during basal and hypoxic conditions in the pulmonary hypertensive HLNB and compared them to lowland newborn lambs (LLNB, 580 m). Additionally, we compared the vasodilator responses to sildenafil in isolated small pulmonary arteries and the PDE5 mRNA expression and evaluated the vascular remodeling by histomorphometric analysis in these newborn lambs. Under basal conditions, HLNB had a higher PAP and cardiac output compared with LLNB. Sildenafil decreased the PAP during basal conditions and completely prevented the PAP increase during hypoxia in both groups. HLNB showed a greater contractile capacity and a higher maximal dilation to sildenafil. PDE5 mRNA expression did not show significant differences between HLNB and LLNB. The distal pulmonary arteries showed an increased wall thickness in HLNB. Our results showed that HLNB are more sensitive to sildenafil and therefore could be useful for treatment of pulmonary hypertension in high-altitude neonates.
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Affiliation(s)
- Emilio A Herrera
- Program in Pathophysiology, University of Chile, CP 6640871, Santiago, Chile
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Schwenke DO, Tokudome T, Shirai M, Hosoda H, Horio T, Kishimoto I, Kangawa K. Exogenous ghrelin attenuates the progression of chronic hypoxia-induced pulmonary hypertension in conscious rats. Endocrinology 2008; 149:237-44. [PMID: 17916633 DOI: 10.1210/en.2007-0833] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Chronic exposure to hypoxia, a common adverse consequence of most pulmonary disorders, can lead to a sustained increase in pulmonary arterial pressure (PAP), right ventricular hypertrophy, and is, therefore, closely associated with heart failure and increased mortality. Ghrelin, originally identified as an endogenous GH secretagogue, has recently been shown to possess potent vasodilator properties, likely involving modulation of the vascular endothelium and its associated vasoactive peptides. In this study we hypothesized that ghrelin would impede the pathogenesis of pulmonary arterial hypertension during chronic hypoxia (CH). PAP was continuously measured using radiotelemetry, in conscious male Sprague Dawley rats, in normoxia and during 2-wk CH (10% O(2)). During this hypoxic period, rats received a daily sc injection of either saline or ghrelin (150 microg/kg). Subsequently, heart and lung samples were collected for morphological, histological, and molecular analyses. CH significantly elevated PAP in saline-treated rats, increased wall thickness of peripheral pulmonary arteries, and, consequently, induced right ventricular hypertrophy. In these rats, CH also led to the overexpression of endothelial nitric oxide synthase mRNA and protein, as well as endothelin-1 mRNA within the lung. Exogenous ghrelin administration attenuated the CH-induced overexpression of endothelial nitric oxide synthase mRNA and protein, as well as endothelin-1 mRNA. Consequently, ghrelin significantly attenuated the development of pulmonary arterial hypertension, pulmonary vascular remodeling, and right ventricular hypertrophy. These results demonstrate the therapeutic benefits of ghrelin for impeding the pathogenesis of pulmonary hypertension and right ventricular hypertrophy, particularly in subjects prone to CH (e.g. pulmonary disorders).
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Affiliation(s)
- Daryl O Schwenke
- Department of Biochemistry, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan
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Huss-Marp J, Krämer U, Eberlein B, Pfab F, Ring J, Behrendt H, Gulyas AF. Reply. J Allergy Clin Immunol 2007. [DOI: 10.1016/j.jaci.2007.06.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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46
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Tan X, Hu SH, Wang XL. Possible role of nitric oxide in the pathogenesis of pulmonary hypertension in broilers: a synopsis. Avian Pathol 2007; 36:261-7. [PMID: 17620170 DOI: 10.1080/03079450701460765] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitric oxide (NO) produced by vascular endothelial cells is an important determinant of the basal tone of small arteries and arterioles. Impaired endothelial NO production has been implicated in the pathophysiology of pulmonary hypertension in humans. Available data suggest that reduction of endothelial NO synthesis, with evidence of reduced endothelial NO synthase expression in pulmonary arterioles, is associated with increased pulmonary vasomotor tone and vascular remodelling in hypertensive broilers. Supplemental l-arginine, a precursor of NO, has been shown to induce flow-dependent pulmonary vasodilation, to prevent reduced endothelial NO synthase expression and to inhibit vascular remodelling in broilers with pulmonary hypertension. Nevertheless, its effect on pulmonary hypertension syndrome incidence is limited. It appears that impaired production of NO is a secondary rather than a causative factor in the pathogenesis of pulmonary hypertension in broilers.
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Affiliation(s)
- Xun Tan
- Department of Veterinary Medicine, Zhejiang University, Hangzhou, PR China
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47
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Schmidt TS, Alp NJ. Mechanisms for the role of tetrahydrobiopterin in endothelial function and vascular disease. Clin Sci (Lond) 2007; 113:47-63. [PMID: 17555404 DOI: 10.1042/cs20070108] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
NO produced by eNOS (endothelial nitric oxide synthase) is a key mediator of vascular homoeostasis. NO bioavailability is reduced early in vascular disease states, such as hypercholesterolaemia, diabetes and hypertension, and throughout the progression of atherosclerosis. This is a result of both reduced NO synthesis and increased NO consumption by reactive oxygen species. eNOS enzymatic activity appears to be determined by the availability of its cofactor BH4 (tetrahydrobiopterin). When BH4 levels are adequate, eNOS produces NO; when BH4 levels are limiting, eNOS becomes enzymatically uncoupled and generates superoxide, contributing to vascular oxidative stress and endothelial dysfunction. BH4 bioavailability is determined by a balance of enzymatic de novo synthesis and recycling, versus oxidative degradation in dysfunctional endothelium. Augmenting vascular BH4 levels by pharmacological supplementation, by enhancing the rate of de novo biosynthesis or by measures to reduce BH4 oxidation have been shown in experimental studies to enhance NO bioavailability. Thus BH4 represents a potential therapeutic target for preserving eNOS function in vascular disease.
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Affiliation(s)
- Tim S Schmidt
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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48
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Huss-Marp J, Krämer U, Eberlein B, Pfab F, Ring J, Behrendt H, Gulyas AF. Reduced exhaled nitric oxide values in children with asthma after inpatient rehabilitation at high altitude. J Allergy Clin Immunol 2007; 120:471-2. [PMID: 17498787 DOI: 10.1016/j.jaci.2007.03.039] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 03/14/2007] [Accepted: 03/27/2007] [Indexed: 11/22/2022]
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49
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Oka M, Karoor V, Homma N, Nagaoka T, Sakao E, Golembeski SM, Limbird J, Imamura M, Gebb SA, Fagan KA, McMurtry IF. Dehydroepiandrosterone upregulates soluble guanylate cyclase and inhibits hypoxic pulmonary hypertension. Cardiovasc Res 2007; 74:377-87. [PMID: 17346686 PMCID: PMC1950784 DOI: 10.1016/j.cardiores.2007.01.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 01/25/2007] [Accepted: 01/31/2007] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE It has been reported that dehydroepiandrosterone is a pulmonary vasodilator and inhibits chronic hypoxia-induced pulmonary hypertension. Additionally, dehydroepiandrosterone has been shown to improve systemic vascular endothelial function. Thus, we hypothesized that chronic treatment with dehydroepiandrosterone would attenuate hypoxic pulmonary hypertension by enhancing pulmonary artery endothelial function. METHODS AND RESULTS Rats were randomly assigned to five groups. Three groups received food containing 0, 0.3, or 1% dehydroepiandrosterone during a 3-wk-exposure to simulated high altitude (HA). The other 2 groups were kept at Denver's low altitude (LA) and received food containing 0 or 1% dehydroepiandrosterone. Dehydroepiandrosterone dose-dependently inhibited hypoxic pulmonary hypertension (mean pulmonary artery pressures after treatment with 0, 0.3, and 1% dehydroepiandrosterone=45+/-5, 33+/-2*, and 25+/-1*# mmHg, respectively. *P<0.05 vs. 0% and # vs. 0.3%). Dehydroepiandrosterone (1%, 3 wks) treatment started after rats had been exposed to 3-wk hypoxia also effectively reversed established hypoxic pulmonary hypertension. Pulmonary artery rings isolated from both LA and HA rats treated with 1% dehydroepiandrosterone showed enhanced relaxations to acetylcholine and sodium nitroprusside, but not to 8-bromo-cGMP. In the pulmonary artery tissue from dehydroepiandrosterone-treated LA and HA rats, soluble guanylate cyclase, but not endothelial nitric oxide synthase, protein levels were increased. CONCLUSION These results indicate that the protective effect of dehydroepiandrosterone against hypoxic pulmonary hypertension may involve upregulation of pulmonary artery soluble guanylate cyclase protein expression and augmented pulmonary artery vasodilator responsiveness to nitric oxide.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Blotting, Western
- Cyclic GMP/pharmacology
- Dehydroepiandrosterone/metabolism
- Dehydroepiandrosterone/therapeutic use
- Dehydroepiandrosterone Sulfate/blood
- Dehydroepiandrosterone Sulfate/metabolism
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Estradiol/blood
- Guanylate Cyclase/analysis
- Guanylate Cyclase/metabolism
- Hypertension, Pulmonary/blood
- Hypertension, Pulmonary/drug therapy
- Hypertension, Pulmonary/metabolism
- Hypoxia/metabolism
- In Vitro Techniques
- Lung/enzymology
- Male
- Muscle, Smooth, Vascular/metabolism
- Nitric Oxide/metabolism
- Nitric Oxide Synthase Type III/analysis
- Nitric Oxide Synthase Type III/antagonists & inhibitors
- Nitroprusside/pharmacology
- Pulmonary Artery/drug effects
- Pulmonary Artery/metabolism
- Pulmonary Artery/physiopathology
- Random Allocation
- Rats
- Rats, Sprague-Dawley
- Receptors, Cytoplasmic and Nuclear/analysis
- Receptors, Cytoplasmic and Nuclear/metabolism
- Soluble Guanylyl Cyclase
- Testosterone/blood
- Up-Regulation
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Masahiko Oka
- Cardiovascular Pulmonary Research Laboratory, Department of Medicine, University of Colorado at Denver and Health Sciences Center, Denver Colorado 80262, United States.
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Role of reactive oxygen species in chronic hypoxia-induced pulmonary hypertension and vascular remodeling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 618:101-12. [PMID: 18269191 DOI: 10.1007/978-0-387-75434-5_8] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pulmonary hypertension is a life-threatening disease process that affects adults and children. Pediatric patients with lung diseases that can be complicated by alveolar hypoxia, such as bronchopulmonary dysplasia (BPD), are at risk for developing pulmonary hypertension, which leads to right heart failure and greatly increases morbidity and mortality. We review the evidence that reactive oxygen species (ROS) are generated by pulmonary vascular wall cells in response to a hypoxic exposure, and that this response contributes to chronic hypoxic pulmonary hypertension. We summarize the accumulating data implicating NADPH oxidase as a major source of O2 responsible for vascular remodeling and hypertension. We also consider the effects of chronic hypoxia on the clearance of O2 by superoxide dismutases, specifically extracellular superoxide dismutase, which is highly expressed in the pulmonary artery. We review the role of the activated vascular adventitial fibroblast in the generation of ROS and in the pathogenesis of vascular remodeling, and provide a rationale to consider the role of the activated fibroblast and ROS in hypoxic pulmonary hypertension using a clinically relevant bovine model of neonatal chronic hypoxic pulmonary hypertension.
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