Comprehensive Physiology Wiley Online Library

Reactive Oxygen Species in Pulmonary Vascular Remodeling

Full Article on Wiley Online Library



Abstract

The pathogenesis of pulmonary hypertension is a complex multifactorial process that involves the remodeling of pulmonary arteries. This remodeling process encompasses concentric medial thickening of small arterioles, neomuscularization of previously nonmuscular capillary‐like vessels, and structural wall changes in larger pulmonary arteries. The pulmonary arterial muscularization is characterized by vascular smooth muscle cell hyperplasia and hypertrophy. In addition, in uncontrolled pulmonary hypertension, the clonal expansion of apoptosis‐resistant endothelial cells leads to the formation of plexiform lesions. Based upon a large number of studies in animal models, the three major stimuli that drive the vascular remodeling process are inflammation, shear stress, and hypoxia. Although, the precise mechanisms by which these stimuli impair pulmonary vascular function and structure are unknown, reactive oxygen species (ROS)‐mediated oxidative damage appears to play an important role. ROS are highly reactive due to their unpaired valence shell electron. Oxidative damage occurs when the production of ROS exceeds the quenching capacity of the antioxidant mechanisms of the cell. ROS can be produced from complexes in the cell membrane (nicotinamide adenine dinucleotide phosphate‐oxidase), cellular organelles (peroxisomes and mitochondria), and in the cytoplasm (xanthine oxidase). Furthermore, low levels of tetrahydrobiopterin (BH4) and L‐arginine the rate limiting cofactor and substrate for endothelial nitric oxide synthase (eNOS), can cause the uncoupling of eNOS, resulting in decreased NO production and increased ROS production. This review will focus on the ROS generation systems, scavenger antioxidants, and oxidative stress associated alterations in vascular remodeling in pulmonary hypertension. © 2013 American Physiological Society. Compr Physiol 3:1011‐1034, 2013.

Comprehensive Physiology offers downloadable PowerPoint presentations of figures for non-profit, educational use, provided the content is not modified and full credit is given to the author and publication.

Download a PowerPoint presentation of all images


Figure 1. Figure 1.

Schematic view of the pathology of pulmonary hypertension (PH). The figure summarizes the major pathological events that lead to the development of PH. In humans, PH is a complex and multifactorial, diffuse disorder of the pulmonary vasculature. However, for the purposes of research and inducing PH in animal models, the etiology of PH can be broadly distinguished into: (A) inflammatory; (B) high shear stress; and (C) hypoxia, even though none of these factors act alone during the progression of the disease. A common mechanism by which these insults provoke vascular dysfunction is by either increasing the production of reactive oxygen species (ROS) or by attenuating the ROS scavenging capability of the cells. Once produced, ROS can influence the growth and morphology of all three layers of the pulmonary vessels. In endothelial cells, ROS promote endothelial proliferation, decrease NO production, and increase the release of vasoactive mediators, leading to endothelial dysfunction. In smooth muscle cells (SMC), oxidative stress caused by ROS induces contraction and a switch to a synthetic phenotype. These SMC alterations are brought about by increasing the intracellular free Ca2+ and decreasing the expression of contractile phenotypic markers, while simultaneously enhancing the expression of proliferative phenotypic markers and growth factors. ROS can also augment the proliferation of fibroblasts in the adventitial layer and their expansion between the endothelium and the internal elastic lamina, known as the neointima (not depicted in the figure). Together, these changes result in vascular remodeling and the development of PH.

Figure 2. Figure 2.

Reactive oxygen species (ROS) generation in pulmonary hypertension. The major sources of ROS in the vasculature include uncoupled endothelial nitric oxide synthase (eNOS), mitochondrial dysfunction, NADPH oxidase, and xanthine oxidase (XO). In pulmonary hypertension (PH), all of these sources contribute to the development of oxidative stress. eNOS uncoupling is mediated by limited L‐arginine availability, as a result of increased degradation by arginase upregulation and attenuated synthesis by the downregulation of argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL), the enzymes responsible for the conversion of L‐citrulline to L‐arginine. Moreover, a sustained increase in asymmetric dimethyl‐l‐arginine (ADMA) levels, due to a decrease in dimethylarginine dimethylaminohydrolase 2 (DDAH2) activity, competes with L‐arginine for binding to eNOS. In addition, in PH, eNOS function is impaired by a decrease in BH4, an essential cofactor for NO generation. GTP cyclohydrolase I (GCH1), the rate‐limiting enzyme in BH4 biosynthesis, is ubiquinated and targeted for degradation by Hsp70/CHIP. Therefore, the low GCH1 levels, limit the production of BH4. Finally, the disruption of the zinc tetrathiolate (ZnS4) cluster by oxidative attack disrupts the eNOS dimer, which is accompanied by decreased NO generation and increased ROS production. Further, in PH, several markers of mitochondrial dysfunction are observed, including increased levels of uncoupling protein‐2 (UCP‐2), decreased levels of the mitochondrial antioxidant, superoxide dismutase‐2 (SOD2), and the impaired function of complexes I, II, and III of the respiratory chain. Interestingly, ADMA appears to promote these changes in the mitochondria, and also augment mitochondrial ROS generation and decrease ATP production. In addition, several subunits of NADPH oxidase, including p47phox, p67phox, gp91phox, and Rac1, are upregulated in PH, increasing ROS production in the vasculature. Increased levels and activity of XO also contribute to oxidative stress and vascular dysfunction in the early stages of PH.

Figure 3. Figure 3.

Reactive oxygen species (ROS) signaling in pulmonary hypertension. The vasoactive mediators that contribute to the development of pulmonary vascular remodeling and pulmonary hypertension (PH) can be broadly divided into two major categories: factors affecting vascular tone and factors influencing vessel wall thickening. ROS influence the generation of several of these factors. In PH, ROS decrease the expression and/or function of redox sensitive voltage gated K+ channels (Kv1.5 and Kv2.1), leading to elevations in intracellular K+ and Ca2+ influx through the activation of voltage‐gated L‐type Ca2+ channels. In turn, Ca2+ induces smooth muscle cell (SMC) contraction through the calmodulin‐dependent activation of myosin light chain kinase (MLCK) and the subsequent phosphorylation of the myosin light chain (MLC). ROS also promote the activation of the small GTPase, RhoA, and its downstream effector, Rho kinase, which increase the phosphorylation of MLC through the inhibition of MLC phosphatase. In addition, ROS promote pulmonary vessel constriction by enhancing the production of endothelin‐1 (ET‐1) and thromboxane A2 (TXA2), while attenuating the levels of vasodilators, such as prostacyclin and peroxisome proliferator‐activated receptors‐γ (PPAR‐γ). The role of ROS in mediating pulmonary SMC proliferation and vessel thickening is more complex. Oxidative stress induces the expression of several growth factors, such as transforming growth factor‐β1 (TGF‐β1), vascular endothelial growth factor (VEGF), fibroblast growth factor‐2 (FGF‐2), and platelet‐derived growth factor (PDGF). In addition, ROS also activate p38MAPK and ERK1/2, which promote proliferation. The MAPK signaling pathway is also activated by pp60Src, through ROS‐mediated activation. Further, ROS stimulate Akt1, which promotes SMC proliferation through the upregulation of PGC‐1α. Together, the dysregulation of these constrictive and proliferative factors by ROS promotes the vascular remodeling seen in PH.

Figure 4. Figure 4.

Reactive oxygen species (ROS) scavenging in pulmonary hypertension. ROS are scavenged by antioxidant systems to preserve the cellular redox homeostasis and to prevent oxidative damage to cellular proteins, lipids, and DNA. The major vascular enzymatic antioxidants are superoxide dismutase (SOD), catalase, and GPx. There are three types of SOD: cytoplasmic Cu/ZnSOD (SOD1), mitochondrial MnSOD (SOD2), and extracellular EC‐SOD (SOD3) that catalyze the rapid conversion of O2 into H2O2. In PH, there is a decrease in the expression and/or activity of all three SOD isoforms, increasing O2 levels. The H2O2 that is produced by SOD can be enzymatically reduced in the cytoplasm by catalase and GPx. Catalase decomposes H2O2 to O2 and H2O, while GPx requires two molecules of glutathione (GSH) to reduce one molecule of H2O2 to two molecules of H2O and in the process GSH is oxidized to glutathione disulfide (GSSG). Catalase activity/expression is altered in PH, while the expression/activity of GPx is decreased in many forms of PH. The result of reduced ROS quenching by these antioxidants adds to the oxidative stress observed in PH.



Figure 1.

Schematic view of the pathology of pulmonary hypertension (PH). The figure summarizes the major pathological events that lead to the development of PH. In humans, PH is a complex and multifactorial, diffuse disorder of the pulmonary vasculature. However, for the purposes of research and inducing PH in animal models, the etiology of PH can be broadly distinguished into: (A) inflammatory; (B) high shear stress; and (C) hypoxia, even though none of these factors act alone during the progression of the disease. A common mechanism by which these insults provoke vascular dysfunction is by either increasing the production of reactive oxygen species (ROS) or by attenuating the ROS scavenging capability of the cells. Once produced, ROS can influence the growth and morphology of all three layers of the pulmonary vessels. In endothelial cells, ROS promote endothelial proliferation, decrease NO production, and increase the release of vasoactive mediators, leading to endothelial dysfunction. In smooth muscle cells (SMC), oxidative stress caused by ROS induces contraction and a switch to a synthetic phenotype. These SMC alterations are brought about by increasing the intracellular free Ca2+ and decreasing the expression of contractile phenotypic markers, while simultaneously enhancing the expression of proliferative phenotypic markers and growth factors. ROS can also augment the proliferation of fibroblasts in the adventitial layer and their expansion between the endothelium and the internal elastic lamina, known as the neointima (not depicted in the figure). Together, these changes result in vascular remodeling and the development of PH.



Figure 2.

Reactive oxygen species (ROS) generation in pulmonary hypertension. The major sources of ROS in the vasculature include uncoupled endothelial nitric oxide synthase (eNOS), mitochondrial dysfunction, NADPH oxidase, and xanthine oxidase (XO). In pulmonary hypertension (PH), all of these sources contribute to the development of oxidative stress. eNOS uncoupling is mediated by limited L‐arginine availability, as a result of increased degradation by arginase upregulation and attenuated synthesis by the downregulation of argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL), the enzymes responsible for the conversion of L‐citrulline to L‐arginine. Moreover, a sustained increase in asymmetric dimethyl‐l‐arginine (ADMA) levels, due to a decrease in dimethylarginine dimethylaminohydrolase 2 (DDAH2) activity, competes with L‐arginine for binding to eNOS. In addition, in PH, eNOS function is impaired by a decrease in BH4, an essential cofactor for NO generation. GTP cyclohydrolase I (GCH1), the rate‐limiting enzyme in BH4 biosynthesis, is ubiquinated and targeted for degradation by Hsp70/CHIP. Therefore, the low GCH1 levels, limit the production of BH4. Finally, the disruption of the zinc tetrathiolate (ZnS4) cluster by oxidative attack disrupts the eNOS dimer, which is accompanied by decreased NO generation and increased ROS production. Further, in PH, several markers of mitochondrial dysfunction are observed, including increased levels of uncoupling protein‐2 (UCP‐2), decreased levels of the mitochondrial antioxidant, superoxide dismutase‐2 (SOD2), and the impaired function of complexes I, II, and III of the respiratory chain. Interestingly, ADMA appears to promote these changes in the mitochondria, and also augment mitochondrial ROS generation and decrease ATP production. In addition, several subunits of NADPH oxidase, including p47phox, p67phox, gp91phox, and Rac1, are upregulated in PH, increasing ROS production in the vasculature. Increased levels and activity of XO also contribute to oxidative stress and vascular dysfunction in the early stages of PH.



Figure 3.

Reactive oxygen species (ROS) signaling in pulmonary hypertension. The vasoactive mediators that contribute to the development of pulmonary vascular remodeling and pulmonary hypertension (PH) can be broadly divided into two major categories: factors affecting vascular tone and factors influencing vessel wall thickening. ROS influence the generation of several of these factors. In PH, ROS decrease the expression and/or function of redox sensitive voltage gated K+ channels (Kv1.5 and Kv2.1), leading to elevations in intracellular K+ and Ca2+ influx through the activation of voltage‐gated L‐type Ca2+ channels. In turn, Ca2+ induces smooth muscle cell (SMC) contraction through the calmodulin‐dependent activation of myosin light chain kinase (MLCK) and the subsequent phosphorylation of the myosin light chain (MLC). ROS also promote the activation of the small GTPase, RhoA, and its downstream effector, Rho kinase, which increase the phosphorylation of MLC through the inhibition of MLC phosphatase. In addition, ROS promote pulmonary vessel constriction by enhancing the production of endothelin‐1 (ET‐1) and thromboxane A2 (TXA2), while attenuating the levels of vasodilators, such as prostacyclin and peroxisome proliferator‐activated receptors‐γ (PPAR‐γ). The role of ROS in mediating pulmonary SMC proliferation and vessel thickening is more complex. Oxidative stress induces the expression of several growth factors, such as transforming growth factor‐β1 (TGF‐β1), vascular endothelial growth factor (VEGF), fibroblast growth factor‐2 (FGF‐2), and platelet‐derived growth factor (PDGF). In addition, ROS also activate p38MAPK and ERK1/2, which promote proliferation. The MAPK signaling pathway is also activated by pp60Src, through ROS‐mediated activation. Further, ROS stimulate Akt1, which promotes SMC proliferation through the upregulation of PGC‐1α. Together, the dysregulation of these constrictive and proliferative factors by ROS promotes the vascular remodeling seen in PH.



Figure 4.

Reactive oxygen species (ROS) scavenging in pulmonary hypertension. ROS are scavenged by antioxidant systems to preserve the cellular redox homeostasis and to prevent oxidative damage to cellular proteins, lipids, and DNA. The major vascular enzymatic antioxidants are superoxide dismutase (SOD), catalase, and GPx. There are three types of SOD: cytoplasmic Cu/ZnSOD (SOD1), mitochondrial MnSOD (SOD2), and extracellular EC‐SOD (SOD3) that catalyze the rapid conversion of O2 into H2O2. In PH, there is a decrease in the expression and/or activity of all three SOD isoforms, increasing O2 levels. The H2O2 that is produced by SOD can be enzymatically reduced in the cytoplasm by catalase and GPx. Catalase decomposes H2O2 to O2 and H2O, while GPx requires two molecules of glutathione (GSH) to reduce one molecule of H2O2 to two molecules of H2O and in the process GSH is oxidized to glutathione disulfide (GSSG). Catalase activity/expression is altered in PH, while the expression/activity of GPx is decreased in many forms of PH. The result of reduced ROS quenching by these antioxidants adds to the oxidative stress observed in PH.

References
 1. Abe J, Kusuhara M, Ulevitch RJ, Berk BC, Lee JD. Big mitogen‐activated protein kinase 1 (BMK1) is a redox‐sensitive kinase. J Biol Chem 271: 16586‐16590, 1996.
 2. Abe J, Takahashi M, Ishida M, Lee JD, Berk BC. c‐Src is required for oxidative stress‐mediated activation of big mitogen‐activated protein kinase 1. J Biol Chem 272: 20389‐20394, 1997.
 3. Abe K, Toba M, Alzoubi A, Ito M, Fagan KA, Cool CD, Voelkel NF, McMurtry IF, Oka M. Formation of plexiform lesions in experimental severe pulmonary arterial hypertension. Circulation 121: 2747‐2754, 2010.
 4. Abman SH, Shanley PF, Accurso FJ. Failure of postnatal adaptation of the pulmonary circulation after chronic intrauterine pulmonary hypertension in fetal lambs. J Clin Invest 83: 1849‐1858, 1989.
 5. Adnot S, Raffestin B, Eddahibi S. NO in the lung. Respir Physiol 101: 109‐120, 1995.
 6. Aggarwal S, Gross CM, Kumar S, Datar S, Oishi P, Kalkan G, Schreiber C, Fratz S, Fineman JR, Black SM. Attenuated vasodilatation in lambs with endogenous and exogenous activation of cGMP signaling: Role of protein kinase G nitration. J Cell Physiol 226: 3104‐3113, 2011.
 7. Ahmed MN, Zhang Y, Codipilly C, Zaghloul N, Patel D, Wolin M, Miller EJ. Extracellular superoxide dismutase overexpression can reverse the course of hypoxia‐induced pulmonary hypertension. Mol Med 18: 38‐46, 2012.
 8. Ahmed RS, Seth V, Pasha ST, Banerjee BD. Influence of dietary ginger (Zingiber officinales Rosc) on oxidative stress induced by malathion in rats. Food Chem Toxicol 38: 443‐450, 2000.
 9. Alp NJ, Channon KM. Regulation of endothelial nitric oxide synthase by tetrahydrobiopterin in vascular disease. Arterioscler Thromb Vasc Biol 24: 413‐420, 2004.
 10. Altiere RJ, Olson JW, Gillespie MN. Altered pulmonary vascular smooth muscle responsiveness in monocrotaline‐induced pulmonary hypertension. J Pharmacol Exp Ther 236: 390‐395, 1986.
 11. Ambasta RK, Kumar P, Griendling KK, Schmidt HH, Busse R, Brandes RP. Direct interaction of the novel Nox proteins with p22phox is required for the formation of a functionally active NADPH oxidase. J Biol Chem 279: 45935‐45941, 2004.
 12. Ambasta RK, Schreiber JG, Janiszewski M, Busse R, Brandes RP. Noxa1 is a central component of the smooth muscle NADPH oxidase in mice. Free Radic Biol Med 41: 193‐201, 2006.
 13. Ameshima S, Golpon H, Cool CD, Chan D, Vandivier RW, Gardai SJ, Wick M, Nemenoff RA, Geraci MW, Voelkel NF. Peroxisome proliferator‐activated receptor gamma (PPARgamma) expression is decreased in pulmonary hypertension and affects endothelial cell growth. Circ Res 92: 1162‐1169, 2003.
 14. Archer SL. Diversity of phenotype and function of vascular smooth muscle cells. J Lab Clin Med 127: 524‐529, 1996.
 15. Archer SL, Gomberg‐Maitland M, Maitland ML, Rich S, Garcia JG, Weir EK. Mitochondrial metabolism, redox signaling, and fusion: A mitochondria‐ROS‐HIF‐1alpha‐Kv1.5 O2‐sensing pathway at the intersection of pulmonary hypertension and cancer. Am J Physiol 294: H570‐H578, 2008.
 16. Archer SL, Huang J, Henry T, Peterson D, Weir EK. A redox‐based O2 sensor in rat pulmonary vasculature. Circ Res 73: 1100‐1112, 1993.
 17. Archer SL, Marsboom G, Kim GH, Zhang HJ, Toth PT, Svensson EC, Dyck JR, Gomberg‐Maitland M, Thebaud B, Husain AN, Cipriani N, Rehman J. Epigenetic attenuation of mitochondrial superoxide dismutase 2 in pulmonary arterial hypertension: A basis for excessive cell proliferation and a new therapeutic target. Circulation 121: 2661‐2671, 2010.
 18. Arcot SS, Fagerland JA, Lipke DW, Gillespie MN, Olson JW. Basic fibroblast growth factor alterations during development of monocrotaline‐induced pulmonary hypertension in rats. Growth Factors 12: 121‐130, 1995.
 19. Arrigoni FI, Vallance P, Haworth SG, Leiper JM. Metabolism of asymmetric dimethylarginines is regulated in the lung developmentally and with pulmonary hypertension induced by hypobaric hypoxia. Circulation 107: 1195‐1201, 2003.
 20. Atz AM, Adatia I, Wessel DL. Rebound pulmonary hypertension after inhalation of nitric oxide. Ann Thorac Surg 62: 1759‐1764, 1996.
 21. Auerbach G, Nar H. The pathway from GTP to tetrahydrobiopterin: Three‐dimensional structures of GTP cyclohydrolase I and 6‐pyruvoyl tetrahydropterin synthase. Biol Chem 378: 185‐192, 1997.
 22. Babior BM. The NADPH oxidase of endothelial cells. IUBMB Life 50: 267‐269, 2000.
 23. Barcellos‐Hoff MH, Dix TA. Redox‐mediated activation of latent transforming growth factor‐beta 1. Mol Endocrinol 10: 1077‐1083, 1996.
 24. Barclay AR, Sholler G, Christodolou J, Shun A, Arbuckle S, Dorney S, Stormon MO. Pulmonary hypertension–a new manifestation of mitochondrial disease. J Inherit Metab Dis 28: 1081‐1089, 2005.
 25. Bayraktutan U, Blayney L, Shah AM. Molecular characterization and localization of the NAD(P)H oxidase components gp91‐phox and p22‐phox in endothelial cells. Arterioscler Thromb Vasc Biol 20: 1903‐1911, 2000.
 26. BelAiba RS, Djordjevic T, Bonello S, Flugel D, Hess J, Kietzmann T, Gorlach A. Redox‐sensitive regulation of the HIF pathway under non‐hypoxic conditions in pulmonary artery smooth muscle cells. Biol Chem 385: 249‐257, 2004.
 27. Belik J, McIntyre BA, Enomoto M, Pan J, Grasemann H, Vasquez‐Vivar J. Pulmonary hypertension in the newborn GTP cyclohydrolase I‐deficient mouse. Free Radic Biol Med 51: 2227‐2233, 2011.
 28. Beranek JT. Vascular endothelial cell is a stem cell for neointimal formation after injury. J Thorac Cardiovasc Surg 121: 820‐821, 2001.
 29. Berg JT, Breen EC, Fu Z, Mathieu‐Costello O, West JB. Alveolar hypoxia increases gene expression of extracellular matrix proteins and platelet‐derived growth factor‐B in lung parenchyma. Am J Respir Crit Care Med 158: 1920‐1928, 1998.
 30. Bernard GR, Wheeler AP, Arons MM, Morris PE, Paz HL, Russell JA, Wright PE. A trial of antioxidants N‐acetylcysteine and procysteine in ARDS. The Antioxidant in ARDS Study Group. Chest 112: 164‐172, 1997.
 31. Bierer R, Nitta CH, Friedman J, Codianni S, de Frutos S, Dominguez‐Bautista JA, Howard TA, Resta TC, Bosc LV. NFATc3 is required for chronic hypoxia‐induced pulmonary hypertension in adult and neonatal mice. Am J Physiol 301: L872‐L880, 2011.
 32. Black SM, Bekker JM, Johengen MJ, Parry AJ, Soifer SJ, Fineman JR. Altered regulation of the ET‐1 cascade in lambs with increased pulmonary blood flow and pulmonary hypertension. Pediatr Res 47: 97‐106, 2000.
 33. Black SM, DeVol JM, Wedgwood S. Regulation of fibroblast growth factor‐2 expression in pulmonary arterial smooth muscle cells involves increased reactive oxygen species generation. Am J Physiol 294: C345‐C354, 2008.
 34. Black SM, Grobe A, Mata‐Greenwood E, Noskina Y. Cyclic stretch increases VEGF expression in pulmonary arterial smooth muscle cells via TGF‐1 and reactive oxygen species: A requirement for NAD(P)H oxidase. Conf Proc IEEE Eng Med Biol Soc 7: 5053‐5056, 2004.
 35. Block K, Gorin Y, Hoover P, Williams P, Chelmicki T, Clark RA, Yoneda T, Abboud HE. NAD(P)H oxidases regulate HIF‐2alpha protein expression. J Biol Chem 282: 8019‐8026, 2007.
 36. Bonnet S, Michelakis ED, Porter CJ, Andrade‐Navarro MA, Thebaud B, Bonnet S, Haromy A, Harry G, Moudgil R, McMurtry MS, Weir EK, Archer SL. An abnormal mitochondrial‐hypoxia inducible factor‐1alpha‐Kv channel pathway disrupts oxygen sensing and triggers pulmonary arterial hypertension in fawn hooded rats: Similarities to human pulmonary arterial hypertension. Circulation 113: 2630‐2641, 2006.
 37. Bonnet S, Rochefort G, Sutendra G, Archer SL, Haromy A, Webster L, Hashimoto K, Bonnet SN, Michelakis ED. The nuclear factor of activated T cells in pulmonary arterial hypertension can be therapeutically targeted. Proc Natl Acad Sci U S A 104: 11418‐11423, 2007.
 38. Botney MD. Role of hemodynamics in pulmonary vascular remodeling: Implications for primary pulmonary hypertension. Am J Respir Crit Care Med 159: 361‐364, 1999.
 39. Botney MD, Bahadori L, Gold LI. Vascular remodeling in primary pulmonary hypertension. Potential role for transforming growth factor‐beta. Am J Pathol 144: 286‐295, 1994.
 40. Botney MD, Parks WC, Crouch EC, Stenmark K, Mecham RP. Transforming growth factor‐beta 1 is decreased in remodeling hypertensive bovine pulmonary arteries. J Clin Invest 89: 1629‐1635, 1992.
 41. Bowers R, Cool C, Murphy RC, Tuder RM, Hopken MW, Flores SC, Voelkel NF. Oxidative stress in severe pulmonary hypertension. Am J Respir Crit Care Med 169: 764‐769, 2004.
 42. Brennan LA, Steinhorn RH, Wedgwood S, Mata‐Greenwood E, Roark EA, Russell JA, Black SM. Increased superoxide generation is associated with pulmonary hypertension in fetal lambs: A role for NADPH oxidase. Circ Res 92: 683‐691, 2003.
 43. Broughton BR, Jernigan NL, Norton CE, Walker BR, Resta TC. Chronic hypoxia augments depolarization‐induced Ca2+ sensitization in pulmonary vascular smooth muscle through superoxide‐dependent stimulation of RhoA. Am J Physiol 298: L232‐L242, 2010.
 44. Burke DL, Frid MG, Kunrath CL, Karoor V, Anwar A, Wagner BD, Strassheim D, Stenmark KR. Sustained hypoxia promotes the development of a pulmonary artery‐specific chronic inflammatory microenvironment. Am J Physiol 297: L238‐L250, 2009.
 45. Burnham EL, McCord JM, Bose S, Brown LA, House R, Moss M, Gaydos J. Protandim does not influence alveolar epithelial permeability or intrapulmonary oxidative stress in human subjects with alcohol use disorders. Am J Physiol 302: L688‐L699, 2011.
 46. Chabot F, Mitchell JA, Gutteridge JM, Evans TW. Reactive oxygen species in acute lung injury. Eur Respir J 11: 745‐757, 1998.
 47. Cheng G, Lambeth JD. Alternative mRNA splice forms of NOXO1: differential tissue expression and regulation of Nox1 and Nox3. Gene 356: 118‐126, 2005.
 48. Cheng TH, Shih NL, Chen SY, Loh SH, Cheng PY, Tsai CS, Liu SH, Wang DL, Chen JJ. Reactive oxygen species mediate cyclic strain‐induced endothelin‐1 gene expression via Ras/Raf/extracellular signal‐regulated kinase pathway in endothelial cells. J Mol Cell Cardiol 33: 1805‐1814, 2001.
 49. Cho A, Graves J, Reidy MA. Mitogen‐activated protein kinases mediate matrix metalloproteinase‐9 expression in vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 20: 2527‐2532, 2000.
 50. Christou H, Yoshida A, Arthur V, Morita T, Kourembanas S. Increased vascular endothelial growth factor production in the lungs of rats with hypoxia‐induced pulmonary hypertension. Am J Respir Cell Mol Biol 18: 768‐776, 1998.
 51. Coffer PJ, Jin J, Woodgett JR. Protein kinase B (c‐Akt): a multifunctional mediator of phosphatidylinositol 3‐kinase activation. Biochem J 335 (Pt 1): 1‐13, 1998.
 52. Conner BD, Bernard GR. Acute respiratory distress syndrome. Potential pharmacologic interventions. Clin Chest Med 21: 563‐587, 2000.
 53. Cool CD, Groshong SD, Oakey J, Voelkel NF. Pulmonary hypertension: Cellular and molecular mechanisms. Chest 128: 565S‐571S, 2005.
 54. Cool CD, Stewart JS, Werahera P, Miller GJ, Williams RL, Voelkel NF, Tuder RM. Three‐dimensional reconstruction of pulmonary arteries in plexiform pulmonary hypertension using cell‐specific markers. Evidence for a dynamic and heterogeneous process of pulmonary endothelial cell growth. Am J Pathol 155: 411‐419, 1999.
 55. Csiszar A, Labinskyy N, Olson S, Pinto JT, Gupte S, Wu JM, Hu F, Ballabh P, Podlutsky A, Losonczy G, de Cabo R, Mathew R, Wolin MS, Ungvari Z. Resveratrol prevents monocrotaline‐induced pulmonary hypertension in rats. Hypertension 54: 668‐675, 2009.
 56. Dal‐Pizzol F, Klamt F, Benfato MS, Bernard EA, Moreira JC. Retinol supplementation induces oxidative stress and modulates antioxidant enzyme activities in rat sertoli cells. Free Radic Res 34: 395‐404, 2001.
 57. Darlington DN, Jones RO, Marzella L, Gann DS. Changes in regional vascular resistance and blood volume after hemorrhage in fed and fasted awake rats. J Appl Physiol 78: 2025‐2032, 1995.
 58. de Frutos S, Spangler R, Alo D, Bosc LV. NFATc3 mediates chronic hypoxia‐induced pulmonary arterial remodeling with alpha‐actin up‐regulation. J Biol Chem 282: 15081‐15089, 2007.
 59. Dempsey EC, Frid MG, Aldashev AA, Das M, Stenmark KR. Heterogeneity in the proliferative response of bovine pulmonary artery smooth muscle cells to mitogens and hypoxia: Importance of protein kinase C. Can J Physiol Pharmacol 75: 936‐944, 1997.
 60. Dempsey EC, Wick MJ, Karoor V, Barr EJ, Tallman DW, Wehling CA, Walchak SJ, Laudi S, Le M, Oka M, Majka S, Cool CD, Fagan KA, Klemm DJ, Hersh LB, Gerard NP, Gerard C, Miller YE. Neprilysin null mice develop exaggerated pulmonary vascular remodeling in response to chronic hypoxia. Am J Pathol 174: 782‐796, 2009.
 61. Deng H, Hershenson MB, Lei J, Anyanwu AC, Pinsky DJ, Bentley JK. Pulmonary artery smooth muscle hypertrophy: Roles of glycogen synthase kinase‐3beta and p70 ribosomal S6 kinase. Am J Physiol Lung Cell Mol Physiol 298: L793‐L803, 2010.
 62. Dennis KE, Aschner JL, Milatovic D, Schmidt JW, Aschner M, Kaplowitz MR, Zhang Y, Fike CD. NADPH oxidases and reactive oxygen species at different stages of chronic hypoxia‐induced pulmonary hypertension in newborn piglets. Am J Physiol 297: L596‐L607, 2009.
 63. Deora AA, Win T, Vanhaesebroeck B, Lander HM. A redox‐triggered ras‐effector interaction. Recruitment of phosphatidylinositol 3’‐kinase to Ras by redox stress. J Biol Chem 273: 29923‐29928, 1998.
 64. Dewachter L, Adnot S, Fadel E, Humbert M, Maitre B, Barlier‐Mur AM, Simonneau G, Hamon M, Naeije R, Eddahibi S. Angiopoietin/Tie2 pathway influences smooth muscle hyperplasia in idiopathic pulmonary hypertension. Am J Respir Crit Care Med 174: 1025‐1033, 2006.
 65. Diebold BA, Bokoch GM. Molecular basis for Rac2 regulation of phagocyte NADPH oxidase. Nat Immunol 2: 211‐215, 2001.
 66. Doggrell SA. Rho‐kinase inhibitors show promise in pulmonary hypertension. Exp Opin Investig Drugs 14: 1157‐1159, 2005.
 67. Dorfmuller P, Zarka V, Durand‐Gasselin I, Monti G, Balabanian K, Garcia G, Capron F, Coulomb‐Lhermine A, Marfaing‐Koka A, Simonneau G, Emilie D, Humbert M. Chemokine RANTES in severe pulmonary arterial hypertension. Am J Respir Crit Care Med 165: 534‐539, 2002.
 68. Dschietzig T, Richter C, Bartsch C, Bohme C, Heinze D, Ott F, Zartnack F, Baumann G, Stangl K. Flow‐induced pressure differentially regulates endothelin‐1, urotensin II, adrenomedullin, and relaxin in pulmonary vascular endothelium. Biochem Biophys Res Commun 289: 245‐251, 2001.
 69. Du L, Sullivan CC, Chu D, Cho AJ, Kido M, Wolf PL, Yuan JX, Deutsch R, Jamieson SW, Thistlethwaite PA. Signaling molecules in nonfamilial pulmonary hypertension. N Engl J Med 348: 500‐509, 2003.
 70. Duchen MR. Contributions of mitochondria to animal physiology: From homeostatic sensor to calcium signalling and cell death. J Physiol 516 (Pt 1): 1‐17, 1999.
 71. Duerrschmidt N, Wippich N, Goettsch W, Broemme HJ, Morawietz H. Endothelin‐1 induces NAD(P)H oxidase in human endothelial cells. Biochem Biophys Res Commun 269: 713‐717, 2000.
 72. Eddahibi S, Hanoun N, Lanfumey L, Lesch KP, Raffestin B, Hamon M, Adnot S. Attenuated hypoxic pulmonary hypertension in mice lacking the 5‐hydroxytryptamine transporter gene. J Clin Invest 105: 1555‐1562, 2000.
 73. Eguchi S, Numaguchi K, Iwasaki H, Matsumoto T, Yamakawa T, Utsunomiya H, Motley ED, Kawakatsu H, Owada KM, Hirata Y, Marumo F, Inagami T. Calcium‐dependent epidermal growth factor receptor transactivation mediates the angiotensin II‐induced mitogen‐activated protein kinase activation in vascular smooth muscle cells. J Biol Chem 273: 8890‐8896, 1998.
 74. Faggin E, Puato M, Zardo L, Franch R, Millino C, Sarinella F, Pauletto P, Sartore S, Chiavegato A. Smooth muscle‐specific SM22 protein is expressed in the adventitial cells of balloon‐injured rabbit carotid artery. Arterioscler Thromb Vasc Biol 19: 1393‐1404, 1999.
 75. Farber HW, Loscalzo J. Pulmonary arterial hypertension. N Engl J Med 351: 1655‐1665, 2004.
 76. Farrow KN, Lakshminrusimha S, Reda WJ, Wedgwood S, Czech L, Gugino SF, Davis JM, Russell JA, Steinhorn RH. Superoxide dismutase restores eNOS expression and function in resistance pulmonary arteries from neonatal lambs with persistent pulmonary hypertension. Am J Physiol 295: L979‐L987, 2008.
 77. Favero TG, Zable AC, Abramson JJ. Hydrogen peroxide stimulates the Ca2+ release channel from skeletal muscle sarcoplasmic reticulum. J Biol Chem 270: 25557‐25563, 1995.
 78. Fijalkowska I, Xu W, Comhair SA, Janocha AJ, Mavrakis LA, Krishnamachary B, Zhen L, Mao T, Richter A, Erzurum SC, Tuder RM. Hypoxia inducible‐factor1alpha regulates the metabolic shift of pulmonary hypertensive endothelial cells. Am J Pathol 176: 1130‐1138, 2010.
 79. Fike CD, Aschner JL, Zhang Y, Salvemini D, Kaplowitz MR. Superoxide and chronic hypoxia‐induced pulmonary hypertension in newborn piglets. Chest 128: 555S‐556S, 2005.
 80. Fisher AB, Chien S, Barakat AI, Nerem RM. Endothelial cellular response to altered shear stress. Am J Physiol 281: L529‐L533, 2001.
 81. Fonseca FV, Ravi K, Wiseman D, Tummala M, Harmon C, Ryzhov V, Fineman JR, Black SM. Mass spectroscopy and molecular modeling predict endothelial nitric oxide synthase dimer collapse by hydrogen peroxide through zinc tetrathiolate metal‐binding site disruption. DNA Cell Biol 29: 149‐160, 2010.
 82. Forstermann U. Nitric oxide and oxidative stress in vascular disease. Pflugers Arch 459: 923‐939, 2010.
 83. Forstermann U, Munzel T. Endothelial nitric oxide synthase in vascular disease: From marvel to menace. Circulation 113: 1708‐1714, 2006.
 84. Frank L, Groseclose EE. Preparation for birth into an O2‐rich environment: The antioxidant enzymes in the developing rabbit lung. Pediatr Res 18: 240‐244, 1984.
 85. Freeman BA, Crapo JD. Hyperoxia increases oxygen radical production in rat lungs and lung mitochondria. J Biol Chem 256: 10986‐10992, 1981.
 86. Fresquet F, Pourageaud F, Leblais V, Brandes RP, Savineau JP, Marthan R, Muller B. Role of reactive oxygen species and gp91phox in endothelial dysfunction of pulmonary arteries induced by chronic hypoxia. Br J Pharmacol 148: 714‐723, 2006.
 87. Frid MG, Aldashev AA, Dempsey EC, Stenmark KR. Smooth muscle cells isolated from discrete compartments of the mature vascular media exhibit unique phenotypes and distinct growth capabilities. Circ Res 81: 940‐952, 1997.
 88. Frid MG, Aldashev AA, Nemenoff RA, Higashito R, Westcott JY, Stenmark KR. Subendothelial cells from normal bovine arteries exhibit autonomous growth and constitutively activated intracellular signaling. Arterioscler Thromb Vasc Biol 19: 2884‐2893, 1999.
 89. Frid MG, Dempsey EC, Durmowicz AG, Stenmark KR. Smooth muscle cell heterogeneity in pulmonary and systemic vessels. Importance in vascular disease. Arterioscler Thromb Vasc Biol 17: 1203‐1209, 1997.
 90. Gabbiani G. Evolution and clinical implications of the myofibroblast concept. Cardiovasc Res 38: 545‐548, 1998.
 91. Gabrielli LA, Castro PF, Godoy I, Mellado R, Bourge RC, Alcaino H, Chiong M, Greig D, Verdejo HE, Navarro M, Lopez R, Toro B, Quiroga C, Diaz‐Araya G, Lavandero S, Garcia L. Systemic oxidative stress and endothelial dysfunction is associated with an attenuated acute vascular response to inhaled prostanoid in pulmonary artery hypertension patients. J Card Fail 17: 1012‐1017, 2011.
 92. Gadek JE, DeMichele SJ, Karlstad MD, Pacht ER, Donahoe M, Albertson TE, Van Hoozen C, Wennberg AK, Nelson JL, Noursalehi M. Effect of enteral feeding with eicosapentaenoic acid, gamma‐linolenic acid, and antioxidants in patients with acute respiratory distress syndrome. Enteral Nutrition in ARDS Study Group. Crit Care Med 27: 1409‐1420, 1999.
 93. Gaine SP, Rubin LJ. Primary pulmonary hypertension. Lancet 352: 719‐725, 1998.
 94. Geiger R, Berger RM, Hess J, Bogers AJ, Sharma HS, Mooi WJ. Enhanced expression of vascular endothelial growth factor in pulmonary plexogenic arteriopathy due to congenital heart disease. J Pathol 191: 202‐207, 2000.
 95. Giaid A, Yanagisawa M, Langleben D, Michel RP, Levy R, Shennib H, Kimura S, Masaki T, Duguid WP, Stewart DJ. Expression of endothelin‐1 in the lungs of patients with pulmonary hypertension. N Engl J Med 328: 1732‐1739, 1993.
 96. Gillespie MN, Rippetoe PE, Haven CA, Shiao RT, Orlinska U, Maley BE, Olson JW. Polyamines and epidermal growth factor in monocrotaline‐induced pulmonary hypertension. Am Rev Respir Dis 140: 1463‐1466, 1989.
 97. Golpon HA, Geraci MW, Moore MD, Miller HL, Miller GJ, Tuder RM, Voelkel NF. HOX genes in human lung: Altered expression in primary pulmonary hypertension and emphysema. Am J Pathol 158: 955‐966, 2001.
 98. Gong K, Xing D, Li P, Aksut B, Ambalavanan N, Yang Q, Nozell SE, Oparil S, Chen YF. Hypoxia induces downregulation of PPAR‐gamma in isolated pulmonary arterial smooth muscle cells and in rat lung via transforming growth factor‐beta signaling. Am J Physiol 301: L899‐L907, 2011.
 99. Gong Y, Yi M, Fediuk J, Lizotte PP, Dakshinamurti S. Hypoxic neonatal pulmonary arterial myocytes are sensitized to ROS‐generated 8‐isoprostane. Free Radic Biol Med 48: 882‐894, 2010.
 100. Gongora MC, Qin Z, Laude K, Kim HW, McCann L, Folz JR, Dikalov S, Fukai T, Harrison DG. Role of extracellular superoxide dismutase in hypertension. Hypertension 48: 473‐481, 2006.
 101. Gorin Y, Ricono JM, Kim NH, Bhandari B, Choudhury GG, Abboud HE. Nox4 mediates angiotensin II‐induced activation of Akt/protein kinase B in mesangial cells. Am J Physiol Renal Physiol 285: F219‐L229, 2003.
 102. Granger DN. Role of xanthine oxidase and granulocytes in ischemia‐reperfusion injury. Am J Physiol 255: H1269‐L1275, 1988.
 103. Griendling KK, Sorescu D, Ushio‐Fukai M. NAD(P)H Oxidase: Role in Cardiovascular Biology and Disease. Circ Res 86 (5): 494‐501, 2000.
 104. Grobe AC, Wells SM, Benavidez E, Oishi P, Azakie A, Fineman JR, Black SM. Increased oxidative stress in lambs with increased pulmonary blood flow and pulmonary hypertension: Role of NADPH oxidase and endothelial NO synthase. Am J Physiol 290: L1069‐L1077, 2006.
 105. Gutterman DD. Adventitia‐dependent influences on vascular function. Am J Physiol 277: H1265‐H1272, 1999.
 106. Han CH, Freeman JL, Lee T, Motalebi SA, Lambeth JD. Regulation of the neutrophil respiratory burst oxidase. Identification of an activation domain in p67(phox). J Biol Chem 273: 16663‐16668, 1998.
 107. Hartney T, Birari R, Venkataraman S, Villegas L, Martinez M, Black SM, Stenmark KR, Nozik‐Grayck E. Xanthine oxidase‐derived ROS upregulate Egr‐1 via ERK1/2 in PA smooth muscle cells; model to test impact of extracellular ROS in chronic hypoxia. PloS one 6: e27531, 2011.
 108. Herrmann J, Samee S, Chade A, Rodriguez Porcel M, Lerman LO, Lerman A. Differential effect of experimental hypertension and hypercholesterolemia on adventitial remodeling. Arterioscler Thromb Vasc Biol 25: 447‐453, 2005.
 109. Hirose S, Hosoda Y, Furuya S, Otsuki T, Ikeda E. Expression of vascular endothelial growth factor and its receptors correlates closely with formation of the plexiform lesion in human pulmonary hypertension. Pathol Int 50: 472‐479, 2000.
 110. Hirschi KK, D'Amore PA. Pericytes in the microvasculature. Cardiovasc Res 32: 687‐698, 1996.
 111. Hishikawa K, Nakaki T, Marumo T, Hayashi M, Suzuki H, Kato R, Saruta T. Pressure promotes DNA synthesis in rat cultured vascular smooth muscle cells. J Clin Invest 93: 1975‐1980, 1994.
 112. Hool LC, Arthur PG. Decreasing cellular hydrogen peroxide with catalase mimics the effects of hypoxia on the sensitivity of the L‐type Ca2+ channel to beta‐adrenergic receptor stimulation in cardiac myocytes. Circ Res 91: 601‐609, 2002.
 113. Hoorn CM, Wagner JG, Roth RA. Effects of monocrotaline pyrrole on cultured rat pulmonary endothelium. Toxicol Appl Pharmacol 120: 281‐287, 1993.
 114. Hopkins N, McLoughlin P. The structural basis of pulmonary hypertension in chronic lung disease: Remodelling, rarefaction or angiogenesis? J Anat 201: 335‐348, 2002.
 115. Hu HL, Zhang ZX, Chen CS, Cai C, Zhao JP, Wang X. Effects of mitochondrial potassium channel and membrane potential on hypoxic human pulmonary artery smooth muscle cells. Am J Respir Cell Mol Biol 42: 661‐666, 2010.
 116. Irodova NL, Lankin VZ, Konovalova GK, Kochetov AG, Chazova IE. Oxidative stress in patients with primary pulmonary hypertension. Bulletin of experimental biology and medicine 133: 580‐582, 2002.
 117. Irrcher I, Ljubicic V, Hood DA. Interactions between ROS and AMP kinase activity in the regulation of PGC‐1alpha transcription in skeletal muscle cells. Am J Physiol 296: C116‐C123, 2009.
 118. Irwin DC, McCord JM, Nozik‐Grayck E, Beckly G, Foreman B, Sullivan T, White M, T Crossno J Jr, Bailey D, Flores SC, Majka S, Klemm D, van Patot MC. A potential role for reactive oxygen species and the HIF‐1alpha‐VEGF pathway in hypoxia‐induced pulmonary vascular leak. Free Radic Biol Med 47: 55‐61, 2009.
 119. Jankov RP, Kantores C, Pan J, Belik J. Contribution of xanthine oxidase‐derived superoxide to chronic hypoxic pulmonary hypertension in neonatal rats. Am J Physiol 294: L233‐L245, 2008.
 120. Jarasch ED, Grund C, Bruder G, Heid HW, Keenan TW, Franke WW. Localization of xanthine oxidase in mammary‐gland epithelium and capillary endothelium. Cell 25: 67‐82, 1981.
 121. Jernigan NL, Herbert LM, Walker BR, Resta TC. Chronic hypoxia upregulates pulmonary arterial ASIC1: a novel mechanism of enhanced store‐operated Ca2+ entry and receptor‐dependent vasoconstriction. Am J Physiol 302: C931‐C940, 2012.
 122. Jernigan NL, Walker BR, Resta TC. Reactive oxygen species mediate RhoA/Rho kinase‐induced Ca2 +sensitization in pulmonary vascular smooth muscle following chronic hypoxia. Am J Physiol 295: L515‐L529, 2008.
 123. Jin HF, Du SX, Zhao X, Wei HL, Wang YF, Liang YF, Tang CS, Du JB. Effects of endogenous sulfur dioxide on monocrotaline‐induced pulmonary hypertension in rats. Acta Pharmacol Sin 29: 1157‐1166, 2008.
 124. John M.C G, Barry H. Free Radicals and Antioxidants in the Year 2000: A Historical Look to the Future. Annals of the New York Academy of Sciences 899: 136‐147, 2000.
 125. Jones PL, Rabinovitch M. Tenascin‐C is induced with progressive pulmonary vascular disease in rats and is functionally related to increased smooth muscle cell proliferation. Circ Res 79: 1131‐1142, 1996.
 126. Jones R. Ultrastructural analysis of contractile cell development in lung microvessels in hyperoxic pulmonary hypertension. Fibroblasts and intermediate cells selectively reorganize nonmuscular segments. Am J Pathol 141: 1491‐1505, 1992.
 127. Jones R, Jacobson M, Steudel W. alpha‐smooth‐muscle actin and microvascular precursor smooth‐muscle cells in pulmonary hypertension. Am J Respir Cell Mol Biol 20: 582‐594, 1999.
 128. Joppa P, Petrasova D, Stancak B, Dorkova Z, Tkacova R. Oxidative stress in patients with COPD and pulmonary hypertension. Wien klin Wochenschr 119: 428‐434, 2007.
 129. Kamezaki F, Tasaki H, Yamashita K, Tsutsui M, Koide S, Nakata S, Tanimoto A, Okazaki M, Sasaguri Y, Adachi T, Otsuji Y. Gene transfer of extracellular superoxide dismutase ameliorates pulmonary hypertension in rats. Am J Respir Crit Care Med 177: 219‐226, 2008.
 130. Kaneko FT, Arroliga AC, Dweik RA, Comhair SA, Laskowski D, Oppedisano R, Thomassen MJ, Erzurum SC. Biochemical reaction products of nitric oxide as quantitative markers of primary pulmonary hypertension. Am J Respir Crit Care Med 158: 917‐923, 1998.
 131. Karthikeyan K, Bai BR, Gauthaman K, Sathish KS, Devaraj SN. Cardioprotective effect of the alcoholic extract of Terminalia arjuna bark in an in vivo model of myocardial ischemic reperfusion injury. Life Sci 73: 2727‐2739, 2003.
 132. Katayose D, Ohe M, Yamauchi K, Ogata M, Shirato K, Fujita H, Shibahara S, Takishima T. Increased expression of PDGF A‐ and B‐chain genes in rat lungs with hypoxic pulmonary hypertension. Am J Physiol 264: L100‐L106, 1993.
 133. Kawahara T, Ritsick D, Cheng G, Lambeth JD. Point mutations in the proline‐rich region of p22phox are dominant inhibitors of Nox1‐ and Nox2‐dependent reactive oxygen generation. J Biol Chem 280: 31859‐31869, 2005.
 134. Ke Q, Li J, Ding J, Ding M, Wang L, Liu B, Costa M, Huang C. Essential role of ROS‐mediated NFAT activation in TNF‐alpha induction by crystalline silica exposure. Am J Physiol 291: L257‐L264, 2006.
 135. Kinnula VL, Crapo JD. Superoxide Dismutases in the Lung and Human Lung Diseases. Am J Respir Crit Care Med 167 (12): 1600‐1619, 2003.
 136. Knock GA, Snetkov VA, Shaifta Y, Connolly M, Drndarski S, Noah A, Pourmahram GE, Becker S, Aaronson PI, Ward JP. Superoxide constricts rat pulmonary arteries via Rho‐kinase‐mediated Ca(2+) sensitization. Free Radic Biol Med 46: 633‐642, 2009.
 137. Kourembanas S, Hannan RL, Faller DV. Oxygen tension regulates the expression of the platelet‐derived growth factor‐B chain gene in human endothelial cells. J Clin Invest 86: 670‐674, 1990.
 138. Koyama E, Leatherman JL, Shimazu A, Nah HD, Pacifici M. Syndecan‐3, tenascin‐C, and the development of cartilaginous skeletal elements and joints in chick limbs. Dev Dyn 203: 152‐162, 1995.
 139. Krick S, Platoshyn O, Sweeney M, Kim H, Yuan JX. Activation of K+ channels induces apoptosis in vascular smooth muscle cells. Am J Physiol 280: C970‐C979, 2001.
 140. Kucich U, Rosenbloom JC, Abrams WR, Rosenbloom J. Transforming growth factor‐beta stabilizes elastin mRNA by a pathway requiring active Smads, protein kinase C‐delta, and p38. Am J Respir Cell Mol Biol 26: 183‐188, 2002.
 141. Lakshminrusimha S, Russell JA, Wedgwood S, Gugino SF, Kazzaz JA, Davis JM, Steinhorn RH. Superoxide dismutase improves oxygenation and reduces oxidation in neonatal pulmonary hypertension. Am J Respir Crit Care Med 174: 1370‐1377, 2006.
 142. Landmesser U, Dikalov S, Price SR, McCann L, Fukai T, Holland SM, Mitch WE, Harrison DG. Oxidation of tetrahydrobiopterin leads to uncoupling of endothelial cell nitric oxide synthase in hypertension. J Clin Invest 111: 1201‐1209, 2003.
 143. Lapouge K, Smith SJ, Walker PA, Gamblin SJ, Smerdon SJ, Rittinger K. Structure of the TPR domain of p67phox in complex with Rac.GTP. Mol Cell 6: 899‐907, 2000.
 144. Lassus P, Turanlahti M, Heikkila P, Andersson LC, Nupponen I, Sarnesto A, Andersson S. Pulmonary vascular endothelial growth factor and Flt‐1 in fetuses, in acute and chronic lung disease, and in persistent pulmonary hypertension of the newborn. Am J Respir Crit Care Med 164: 1981‐1987, 2001.
 145. Lavoie A, Hall JB, Olson DM, Wylam ME. Life‐threatening effects of discontinuing inhaled nitric oxide in severe respiratory failure. Am J Respir Crit Care Med 153: 1985‐1987, 1996.
 146. Le Cras TD, Kim DH, Gebb S, Markham NE, Shannon JM, Tuder RM, Abman SH. Abnormal lung growth and the development of pulmonary hypertension in the Fawn‐Hooded rat. Am J Physiol 277: L709‐L718, 1999.
 147. Lee DS, McCallum EA, Olson DM. Effects of reactive oxygen species on prostacyclin production in perinatal rat lung cells. J Appl Physiol 66: 1321‐1327, 1989.
 148. Lee SL, Wang WW, Fanburg BL. Dexfenfluramine as a mitogen signal via the formation of superoxide anion. Faseb J 15: 1324‐1325, 2001.
 149. Lee SL, Wang WW, Moore BJ, Fanburg BL. Dual effect of serotonin on growth of bovine pulmonary artery smooth muscle cells in culture. Circ Res 68: 1362‐1368, 1991.
 150. Leiper JM, Santa Maria J, Chubb A, MacAllister RJ, Charles IG, Whitley GS, Vallance P. Identification of two human dimethylarginine dimethylaminohydrolases with distinct tissue distributions and homology with microbial arginine deiminases. Biochem J 343 (Pt 1): 209‐214, 1999.
 151. Levin DL, Heymann MA, Kitterman JA, Gregory GA, Phibbs RH, Rudolph AM. Persistent pulmonary hypertension of the newborn infant. J Pediatr 89: 626‐630, 1976.
 152. Li G, Chen SJ, Oparil S, Chen YF, Thompson JA. Direct in vivo evidence demonstrating neointimal migration of adventitial fibroblasts after balloon injury of rat carotid arteries. Circulation 101: 1362‐1365, 2000.
 153. Li H, Chen SJ, Chen YF, Meng QC, Durand J, Oparil S, Elton TS. Enhanced endothelin‐1 and endothelin receptor gene expression in chronic hypoxia. J Appl Physiol 77: 1451‐1459, 1994.
 154. Li JM, Shah AM. Intracellular localization and preassembly of the NADPH oxidase complex in cultured endothelial cells. J Biol Chem 277: 19952‐19960, 2002.
 155. Li P, Oparil S, Sun JZ, Thompson JA, Chen YF. Fibroblast growth factor mediates hypoxia‐induced endothelin–a receptor expression in lung artery smooth muscle cells. J Appl Physiol 95: 643‐651; discussion 863, 2003.
 156. Li S, Tabar SS, Malec V, Eul BG, Klepetko W, Weissmann N, Grimminger F, Seeger W, Rose F, Hanze J. NOX4 regulates ROS levels under normoxic and hypoxic conditions, triggers proliferation, and inhibits apoptosis in pulmonary artery adventitial fibroblasts. Antioxid Redox Signal 10: 1687‐1698, 2008.
 157. Lin MJ, Leung GP, Zhang WM, Yang XR, Yip KP, Tse CM, Sham JS. Chronic hypoxia‐induced upregulation of store‐operated and receptor‐operated Ca2+ channels in pulmonary arterial smooth muscle cells: A novel mechanism of hypoxic pulmonary hypertension. Circ Res 95: 496‐505, 2004.
 158. Lin MJ, Yang XR, Cao YN, Sham JS. Hydrogen peroxide‐induced Ca2+ mobilization in pulmonary arterial smooth muscle cells. Am J Physiol 292: L1598‐L1608, 2007.
 159. Lipsitz EC, Weinstein S, Smerling AJ, Stolar CJ. Endogenous nitric oxide and pulmonary vascular tone in the neonate. J Pediatr Surg 31: 137‐140, 1996.
 160. Liu Y, Cox SR, Morita T, Kourembanas S. Hypoxia regulates vascular endothelial growth factor gene expression in endothelial cells. Identification of a 5’ enhancer. Circ Res 77: 638‐643, 1995.
 161. Liu Y, Fanburg BL. Serotonin‐induced growth of pulmonary artery smooth muscle requires activation of phosphatidylinositol 3‐kinase/serine‐threonine protein kinase B/mammalian target of rapamycin/p70 ribosomal S6 kinase 1. Am J Respir Cell Mol Biol 34: 182‐191, 2006.
 162. Lopez‐Ongil S, Saura M, Zaragoza C, Gonzalez‐Santiago L, Rodriguez‐Puyol M, Lowenstein CJ, Rodriguez‐Puyol D. Hydrogen peroxide regulation of bovine endothelin‐converting enzyme‐1. Free Radic Biol Med 32: 406‐413, 2002.
 163. Maarsingh H, Dekkers BG, Zuidhof AB, Bos IS, Menzen MH, Klein T, Flik G, Zaagsma J, Meurs H. Increased arginase activity contributes to airway remodelling in chronic allergic asthma. Eur Respir J 38: 318‐328, 2011.
 164. Martyn KD, Frederick LM, von Loehneysen K, Dinauer MC, Knaus UG. Functional analysis of Nox4 reveals unique characteristics compared to other NADPH oxidases. Cell Signal 18: 69‐82, 2006.
 165. Maruyama J, Jiang BH, Maruyama K, Takata M, Miyasaka K. Prolonged nitric oxide inhalation during recovery from chronic hypoxia does not decrease nitric oxide‐dependent relaxation in pulmonary arteries. Chest 126: 1919‐1925, 2004.
 166. Masri FA, Comhair SA, Dostanic‐Larson I, Kaneko FT, Dweik RA, Arroliga AC, Erzurum SC. Deficiency of lung antioxidants in idiopathic pulmonary arterial hypertension. Clin Transl Sci 1: 99‐106, 2008.
 167. Mata‐Greenwood E, Meyrick B, Soifer SJ, Fineman JR, Black SM. Expression of VEGF and its receptors Flt‐1 and Flk‐1/KDR is altered in lambs with increased pulmonary blood flow and pulmonary hypertension. Am J Physiol 285: L222‐L231, 2003.
 168. Mata‐Greenwood E, Meyrick B, Steinhorn RH, Fineman JR, Black SM. Alterations in TGF‐beta1 expression in lambs with increased pulmonary blood flow and pulmonary hypertension. Am J Physiol 285: L209‐L221, 2003.
 169. Mattocks AR. Toxicity of pyrrolizidine alkaloids. Nature 217: 723‐728, 1968.
 170. Mattocks AR, Jukes R. Recovery of the pyrrolic nucleus of pyrrolizidine alkaloid metabolites from sulphur conjugates in tissues and body fluids. Chem Biol Interact 75: 225‐239, 1990.
 171. McKenzie JC, Clancy J, Jr., Klein RM. Autoradiographic analysis of cell proliferation and protein synthesis in the pulmonary trunk of rats during the early development of hypoxia‐induced pulmonary hypertension. Blood Vessels 21: 80‐89, 1984.
 172. McMurtry MS, Bonnet S, Wu X, Dyck JR, Haromy A, Hashimoto K, Michelakis ED. Dichloroacetate prevents and reverses pulmonary hypertension by inducing pulmonary artery smooth muscle cell apoptosis. Circ Res 95: 830‐840, 2004.
 173. McQueston JA, Kinsella JP, Ivy DD, McMurtry IF, Abman SH. Chronic pulmonary hypertension in utero impairs endothelium‐dependent vasodilation. Am J Physiol 268: H288‐H294, 1995.
 174. Mehta S, Stewart DJ, Langleben D, Levy RD. Short‐term pulmonary vasodilation with L‐arginine in pulmonary hypertension. Circulation 92: 1539‐1545, 1995.
 175.Meyrick B, Reid L. The effect of continued hypoxia on rat pulmonary arterial circulation. An ultrastructural study. Lab Invest 38: 188‐200, 1978.
 176.Meyrick B, Reid L. Development of pulmonary arterial changes in rats fed Crotalaria spectabilis. Am J Pathol 94: 37‐50, 1979.
 177.Meyrick B, Reid L. Hypoxia and incorporation of 3H‐thymidine by cells of the rat pulmonary arteries and alveolar wall. Am J Pathol 96: 51‐70, 1979.
 178.Meyrick B, Reid L. Endothelial and subintimal changes in rat hilar pulmonary artery during recovery from hypoxia. A quantitative ultrastructural study. Lab Invest 42: 603‐615, 1980.
 179.Meyrick B, Reid L. Hypoxia‐induced structural changes in the media and adventitia of the rat hilar pulmonary artery and their regression. Am J Pathol 100: 151‐178, 1980.
 180. Meyrick BO, Reid LM. Crotalaria‐induced pulmonary hypertension. Uptake of 3H‐thymidine by the cells of the pulmonary circulation and alveolar walls. Am J Pathol 106: 84‐94, 1982.
 181. Mittal M, Gu XQ, Pak O, Pamenter ME, Haag D, Fuchs DB, Schermuly RT, Ghofrani HA, Brandes RP, Seeger W, Grimminger F, Haddad GG, Weissmann N. Hypoxia induces Kv channel current inhibition by increased NADPH oxidase‐derived reactive oxygen species. Free Radic Biol Med 52: 1033‐1042, 2012.
 182. Mittal M, Roth M, Konig P, Hofmann S, Dony E, Goyal P, Selbitz AC, Schermuly RT, Ghofrani HA, Kwapiszewska G, Kummer W, Klepetko W, Hoda MA, Fink L, Hanze J, Seeger W, Grimminger F, Schmidt HH, Weissmann N. Hypoxia‐dependent regulation of nonphagocytic NADPH oxidase subunit NOX4 in the pulmonary vasculature. Circ Res 101: 258‐267, 2007.
 183. Montisano DF, Mann T, Spragg RG. H2O2 increases expression of pulmonary artery endothelial cell platelet‐derived growth factor mRNA. J Appl Physiol 73: 2255‐2262, 1992.
 184. Morin FC, III. Ligating the ductus arteriosus before birth causes persistent pulmonary hypertension in the newborn lamb. Pediatr Res 25: 245‐250, 1989.
 185. Morris CR, Kato GJ, Poljakovic M, Wang X, Blackwelder WC, Sachdev V, Hazen SL, Vichinsky EP, Morris SM, Jr., Gladwin MT. Dysregulated arginine metabolism, hemolysis‐associated pulmonary hypertension, and mortality in sickle cell disease. Jama 294: 81‐90, 2005.
 186. Nagaoka T, Morio Y, Casanova N, Bauer N, Gebb S, McMurtry I, Oka M. Rho/Rho kinase signaling mediates increased basal pulmonary vascular tone in chronically hypoxic rats. Am J Physiol 287: L665‐L672, 2004.
 187. Nakano Y, Banfi B, Jesaitis AJ, Dinauer MC, Allen LA, Nauseef WM. Critical roles for p22phox in the structural maturation and subcellular targeting of Nox3. Biochem J 403: 97‐108, 2007.
 188. Nelson SK, Bose SK, Grunwald GK, Myhill P, McCord JM. The induction of human superoxide dismutase and catalase in vivo: A fundamentally new approach to antioxidant therapy. Free Radic Biol Med 40: 341‐347, 2006.
 189. Nisbet RE, Bland JM, Kleinhenz DJ, Mitchell PO, Walp ER, Sutliff RL, Hart CM. Rosiglitazone attenuates chronic hypoxia‐induced pulmonary hypertension in a mouse model. Am J Respir Cell Mol Biol 42: 482‐490, 2010.
 190. Nisbet RE, Graves AS, Kleinhenz DJ, Rupnow HL, Reed AL, Fan TH, Mitchell PO, Sutliff RL, Hart CM. The role of NADPH oxidase in chronic intermittent hypoxia‐induced pulmonary hypertension in mice. Am J Respir Cell Mol Biol 40: 601‐609, 2009.
 191. Oishi P, Grobe A, Benavidez E, Ovadia B, Harmon C, Ross GA, Hendricks‐Munoz K, Xu J, Black SM, Fineman JR. Inhaled nitric oxide induced NOS inhibition and rebound pulmonary hypertension: A role for superoxide and peroxynitrite in the intact lamb. Am J Physiol 290: L359‐L366, 2006.
 192. Oka M, Homma N, Taraseviciene‐Stewart L, Morris KG, Kraskauskas D, Burns N, Voelkel NF, McMurtry IF. Rho kinase‐mediated vasoconstriction is important in severe occlusive pulmonary arterial hypertension in rats. Circ Res 100: 923‐929, 2007.
 193. Okada K, Tanaka Y, Bernstein M, Zhang W, Patterson GA, Botney MD. Pulmonary hemodynamics modify the rat pulmonary artery response to injury. A neointimal model of pulmonary hypertension. Am J Pathol 151: 1019‐1025, 1997.
 194. Paddenberg R, Ishaq B, Goldenberg A, Faulhammer P, Rose F, Weissmann N, Braun‐Dullaeus RC, Kummer W. Essential role of complex II of the respiratory chain in hypoxia‐induced ROS generation in the pulmonary vasculature. Am J Physiol 284: L710‐L719, 2003.
 195. Paky A, Michael JR, Burke‐Wolin TM, Wolin MS, Gurtner GH. Endogenous production of superoxide by rabbit lungs: Effects of hypoxia or metabolic inhibitors. J Appl Physiol 74: 2868‐2874, 1993.
 196. Pan LC, Lame MW, Morin D, Wilson DW, Segall HJ. Red blood cells augment transport of reactive metabolites of monocrotaline from liver to lung in isolated and tandem liver and lung preparations. Toxicol Appl Pharmacol 110: 336‐346, 1991.
 197. Paravicini TM, Gulluyan LM, Dusting GJ, Drummond GR. Increased NADPH oxidase activity, gp91phox expression, and endothelium‐dependent vasorelaxation during neointima formation in rabbits. Circ Res 91: 54‐61, 2002.
 198. Paravicini TM, Touyz RM. NADPH oxidases, reactive oxygen species, and hypertension: Clinical implications and therapeutic possibilities. Diabetes Care 31 (Suppl 2): S170‐180, 2008.
 199. Parkos CA, Dinauer MC, Jesaitis AJ, Orkin SH, Curnutte JT. Absence of both the 91kD and 22kD subunits of human neutrophil cytochrome b in two genetic forms of chronic granulomatous disease. Blood 73: 1416‐1420, 1989.
 200. Parviz M, Bousamra M, II, Chammas JH, Birks EK, Presberg KW, Jacobs ER, Nelin LD. Effects of chronic pulmonary overcirculation on pulmonary vasomotor tone. Ann Thorac Surg 67: 522‐527, 1999.
 201. Perkett EA, Badesch DB, Roessler MK, Stenmark KR, Meyrick B. Insulin‐like growth factor I and pulmonary hypertension induced by continuous air embolization in sheep. Am J Respir Cell Mol Biol 6: 82‐87, 1992.
 202. Pey A, Saborido A, Blazquez I, Delgado J, Megias A. Effects of prolonged stanozolol treatment on antioxidant enzyme activities, oxidative stress markers, and heat shock protein HSP72 levels in rat liver. J Steroid Biochem Mol Biol 87: 269‐277, 2003.
 203. Poiani GJ, Tozzi CA, Yohn SE, Pierce RA, Belsky SA, Berg RA, Yu SY, Deak SB, Riley DJ. Collagen and elastin metabolism in hypertensive pulmonary arteries of rats. Circ Res 66: 968‐978, 1990.
 204. Pourmahram GE, Snetkov VA, Shaifta Y, Drndarski S, Knock GA, Aaronson PI, Ward JP. Constriction of pulmonary artery by peroxide: Role of Ca2+ release and PKC. Free Radic Biol Med 45: 1468‐1476, 2008.
 205. Prosser IW, Stenmark KR, Suthar M, Crouch EC, Mecham RP, Parks WC. Regional heterogeneity of elastin and collagen gene expression in intralobar arteries in response to hypoxic pulmonary hypertension as demonstrated by in situ hybridization. Am J Pathol 135: 1073‐1088, 1989.
 206. Pullamsetti S, Kiss L, Ghofrani HA, Voswinckel R, Haredza P, Klepetko W, Aigner C, Fink L, Muyal JP, Weissmann N, Grimminger F, Seeger W, Schermuly RT. Increased levels and reduced catabolism of asymmetric and symmetric dimethylarginines in pulmonary hypertension. Faseb J 19: 1175‐1177, 2005.
 207. Quinlan CL, Orr AL, Perevoshchikova IV, Treberg JR, Ackrell BA, Brand MD. Mitochondrial complex II can generate reactive oxygen species at high rates in both the forward and reverse reactions. J Biol Chem 287: 27255‐27264, 2012.
 208. Rabinovitch M, Konstam MA, Gamble WJ, Papanicolaou N, Aronovitz MJ, Treves S, Reid L. Changes in pulmonary blood flow affect vascular response to chronic hypoxia in rats. Circ Res 52: 432‐441, 1983.
 209. Rafikov R, Fonseca FV, Kumar S, Pardo D, Darragh C, Elms S, Fulton D, Black SM. eNOS activation and NO function: Structural motifs responsible for the posttranslational control of endothelial nitric oxide synthase activity. J Endocrinol 210: 271‐284, 2011.
 210. Raman CS, Li H, Martasek P, Kral V, Masters BS, Poulos TL. Crystal structure of constitutive endothelial nitric oxide synthase: A paradigm for pterin function involving a novel metal center. Cell 95: 939‐950, 1998.
 211. Rao GN, Corson MA, Berk BC. Uric acid stimulates vascular smooth muscle cell proliferation by increasing platelet‐derived growth factor A‐chain expression. J Biol Chem 266: 8604‐8608, 1991.
 212. Rao J, Li J, Liu Y, Lu P, Sun X, Sugumaran PK, Zhu D. The key role of PGC‐1alpha in mitochondrial biogenesis and the proliferation of pulmonary artery vascular smooth muscle cells at an early stage of hypoxic exposure. Mol Cell Biochem 367 (1‐2): 9‐18, 2012.
 213. Rathore R, Zheng YM, Niu CF, Liu QH, Korde A, Ho YS, Wang YX. Hypoxia activates NADPH oxidase to increase [ROS]i and [Ca2+]i through the mitochondrial ROS‐PKCepsilon signaling axis in pulmonary artery smooth muscle cells. Free Radic Biol Med 45: 1223‐1231, 2008.
 214. Reddy VM, Meyrick B, Wong J, Khoor A, Liddicoat JR, Hanley FL, Fineman JR. In utero placement of aortopulmonary shunts. A model of postnatal pulmonary hypertension with increased pulmonary blood flow in lambs. Circulation 92: 606‐613, 1995.
 215. Reddy VM, Wong J, Liddicoat JR, Johengen M, Chang R, Fineman JR. Altered endothelium‐dependent responses in lambs with pulmonary hypertension and increased pulmonary blood flow. Am J Physiol 271: H562‐H570, 1996.
 216. Redout EM, Wagner MJ, Zuidwijk MJ, Boer C, Musters RJ, van Hardeveld C, Paulus WJ, Simonides WS. Right‐ventricular failure is associated with increased mitochondrial complex II activity and production of reactive oxygen species. Cardiovasc Res 75: 770‐781, 2007.
 217. Reeve HL, Michelakis E, Nelson DP, Weir EK, Archer SL. Alterations in a redox oxygen sensing mechanism in chronic hypoxia. J Appl Physiol 90: 2249‐2256, 2001.
 218. Reid LM. The Third Grover Conference on the pulmonary Circulation. The control of cellular proliferation in the pulmonary circulation. Am Rev Respir Dis 140: 1490‐1493, 1989.
 219. Rose F, Grimminger F, Appel J, Heller M, Pies V, Weissmann N, Fink L, Schmidt S, Krick S, Camenisch G, Gassmann M, Seeger W, Hanze J. Hypoxic pulmonary artery fibroblasts trigger proliferation of vascular smooth muscle cells: Role of hypoxia‐inducible transcription factors. Faseb J 16: 1660‐1661, 2002.
 220. Rosenfeldt FL, Haas SJ, Krum H, Hadj A, Ng K, Leong JY, Watts GF. Coenzyme Q10 in the treatment of hypertension: A meta‐analysis of the clinical trials. J Hum Hypertens 21: 297‐306, 2007.
 221. Rubin LJ. Primary pulmonary hypertension. N Engl J Med 336: 111‐117, 1997.
 222. Rubin LJ, Badesch DB, Barst RJ, Galie N, Black CM, Keogh A, Pulido T, Frost A, Roux S, Leconte I, Landzberg M, Simonneau G. Bosentan therapy for pulmonary arterial hypertension. N Engl J Med 346: 896‐903, 2002.
 223. Rudarakanchana N, Flanagan JA, Chen H, Upton PD, Machado R, Patel D, Trembath RC, Morrell NW. Functional analysis of bone morphogenetic protein type II receptor mutations underlying primary pulmonary hypertension. Hum Mol Genet 11: 1517‐1525, 2002.
 224. Rueckschloss U, Galle J, Holtz J, Zerkowski HR, Morawietz H. Induction of NAD(P)H oxidase by oxidized low‐density lipoprotein in human endothelial cells: Antioxidative potential of hydroxymethylglutaryl coenzyme A reductase inhibitor therapy. Circulation 104: 1767‐1772, 2001.
 225. Sakao S, Taraseviciene‐Stewart L, Lee JD, Wood K, Cool CD, Voelkel NF. Initial apoptosis is followed by increased proliferation of apoptosis‐resistant endothelial cells. Faseb J 19: 1178‐1180, 2005.
 226. Sakao S, Tatsumi K, Voelkel NF. Endothelial cells and pulmonary arterial hypertension: Apoptosis, proliferation, interaction and transdifferentiation. Respir Res 10: 95, 2009.
 227. Sanchez‐Elsner T, Botella LM, Velasco B, Corbi A, Attisano L, Bernabeu C. Synergistic cooperation between hypoxia and transforming growth factor‐beta pathways on human vascular endothelial growth factor gene expression. J Biol Chem 276: 38527‐38535, 2001.
 228. Sasaki A, Doi S, Mizutani S, Azuma H. Roles of accumulated endogenous nitric oxide synthase inhibitors, enhanced arginase activity, and attenuated nitric oxide synthase activity in endothelial cells for pulmonary hypertension in rats. Am J Physiol 292: L1480‐L1487, 2007.
 229. Schermuly RT, Kreisselmeier KP, Ghofrani HA, Samidurai A, Pullamsetti S, Weissmann N, Schudt C, Ermert L, Seeger W, Grimminger F. Antiremodeling effects of iloprost and the dual‐selective phosphodiesterase 3/4 inhibitor tolafentrine in chronic experimental pulmonary hypertension. Circ Res 94: 1101‐1108, 2004.
 230. Schermuly RT, Kreisselmeier KP, Ghofrani HA, Yilmaz H, Butrous G, Ermert L, Ermert M, Weissmann N, Rose F, Guenther A, Walmrath D, Seeger W, Grimminger F. Chronic sildenafil treatment inhibits monocrotaline‐induced pulmonary hypertension in rats. Am J Respir Crit Care Med 169: 39‐45, 2004.
 231. Schmidt TS, Alp NJ. Mechanisms for the role of tetrahydrobiopterin in endothelial function and vascular disease. Clin Sci (Lond) 113: 47‐63, 2007.
 232. Schmitt‐Graff A, Desmouliere A, Gabbiani G. Heterogeneity of myofibroblast phenotypic features: An example of fibroblastic cell plasticity. Virchows Arch 425: 3‐24, 1994.
 233. Schroder E, Eaton P. Hydrogen peroxide as an endogenous mediator and exogenous tool in cardiovascular research: Issues and considerations. Curr Opin Pharmacol 8: 153‐159, 2008.
 234. Scott NA, Cipolla GD, Ross CE, Dunn B, Martin FH, Simonet L, Wilcox JN. Identification of a potential role for the adventitia in vascular lesion formation after balloon overstretch injury of porcine coronary arteries. Circulation 93: 2178‐2187, 1996.
 235. Seta F, Rahmani M, Turner PV, Funk CD. Pulmonary oxidative stress is increased in cyclooxygenase‐2 knockdown mice with mild pulmonary hypertension induced by monocrotaline. PloS One 6: e23439.
 236. Shao Z, Wang Z, Shrestha K, Thakur A, Borowski AG, Sweet W, Thomas JD, Moravec CS, Hazen SL, Tang WH. Pulmonary hypertension associated with advanced systolic heart failure: Dysregulated arginine metabolism and importance of compensatory dimethylarginine dimethylaminohydrolase‐1. J Am Coll Cardiol 59: 1150‐1158, 2012.
 237. Sharma S, Grobe AC, Wiseman DA, Kumar S, Englaish M, Najwer I, Benavidez E, Oishi P, Azakie A, Fineman JR, Black SM. Lung antioxidant enzymes are regulated by development and increased pulmonary blood flow. Am J Physiol 293: L960‐L971, 2007.
 238. Sharma S, Kumar S, Sud N, Wiseman DA, Tian J, Rehmani I, Datar S, Oishi P, Fratz S, Venema RC, Fineman JR, Black SM. Alterations in lung arginine metabolism in lambs with pulmonary hypertension associated with increased pulmonary blood flow. Vascul Pharmacol 51: 359‐364, 2009.
 239. Sharma S, Kumar S, Wiseman DA, Kallarackal S, Ponnala S, Elgaish M, Tian J, Fineman JR, Black SM. Perinatal changes in superoxide generation in the ovine lung: Alterations associated with increased pulmonary blood flow. Vascul Pharmacol 53: 38‐52, 2010.
 240. Sharma S, Sud N, Wiseman DA, Carter AL, Kumar S, Hou Y, Rau T, Wilham J, Harmon C, Oishi P, Fineman JR, Black SM. Altered carnitine homeostasis is associated with decreased mitochondrial function and altered nitric oxide signaling in lambs with pulmonary hypertension. Am J Physiol 294: L46‐L56, 2008.
 241. Sharma S, Sun X, Kumar S, Rafikov R, Aramburo A, Kalkan G, Tian J, Rehmani I, Kallarackal S, Fineman JR, Black SM. Preserving mitochondrial function prevents the proteasomal degradation of GTP cyclohydrolase I. Free Radic Biol Med 53: 216‐229, 2012.
 242. Sheehy AM, Burson MA, Black SM. Nitric oxide exposure inhibits endothelial NOS activity but not gene expression: A role for superoxide. Am J Physiol 274: L833‐L841, 1998.
 243. Shi Y, O'Brien JE, Fard A, Mannion JD, Wang D, Zalewski A. Adventitial myofibroblasts contribute to neointimal formation in injured porcine coronary arteries. Circulation 94: 1655‐1664, 1996.
 244. Sindhu RK, Ehdaie A, Farmand F, Dhaliwal KK, Nguyen T, Zhan CD, Roberts CK, Vaziri ND. Expression of catalase and glutathione peroxidase in renal insufficiency. Biochim Biophys Acta 1743: 86‐92, 2005.
 245. Sluiter I, van Heijst A, Haasdijk R, Kempen MB, Boerema‐de Munck A, Reiss I, Tibboel D, Rottier RJ. Reversal of pulmonary vascular remodeling in pulmonary hypertensive rats. Exp Mol Pathol 93: 66‐73, 2012.
 246. Somlyo AP, Somlyo AV. Signal transduction and regulation in smooth muscle. Nature 372: 231‐236, 1994.
 247. Sproule DM, Dyme J, Coku J, de Vinck D, Rosenzweig E, Chung WK, De Vivo DC. Pulmonary artery hypertension in a child with MELAS due to a point mutation of the mitochondrial tRNA((Leu)) gene (m.3243A > G). J Inherit Metab Dis, 2008 [Epub ahead of print].
 248. Stefanska J, Sarniak A, Wlodarczyk A, Sokolowska M, Pniewska E, Doniec Z, Nowak D, Pawliczak R. Apocynin reduces reactive oxygen species concentrations in exhaled breath condensate in asthmatics. Exp Lung Res 38: 90‐99, 2012.
 249. Steinhorn RH, Albert G, Swartz DD, Russell JA, Levine CR, Davis JM. Recombinant human superoxide dismutase enhances the effect of inhaled nitric oxide in persistent pulmonary hypertension. Am J Respir Crit Care Med 164: 834‐839, 2001.
 250. Steinhubl SR. Why have antioxidants failed in clinical trials? Am J Cardiol 101: 14D‐19D, 2008.
 251. Stenmark KR, Davie N, Frid M, Gerasimovskaya E, Das M. Role of the adventitia in pulmonary vascular remodeling. Physiology (Bethesda) 21: 134‐145, 2006.
 252. Stewart DJ, Levy RD, Cernacek P, Langleben D. Increased plasma endothelin‐1 in pulmonary hypertension: Marker or mediator of disease? Ann Intern Med 114: 464‐469, 1991.
 253. Sturrock A, Cahill B, Norman K, Huecksteadt TP, Hill K, Sanders K, Karwande SV, Stringham JC, Bull DA, Gleich M, Kennedy TP, Hoidal JR. Transforming growth factor‐beta1 induces Nox4 NAD(P)H oxidase and reactive oxygen species‐dependent proliferation in human pulmonary artery smooth muscle cells. Am J Physiol 290: L661‐LL673, 2006.
 254. Sud N, Wells SM, Sharma S, Wiseman DA, Wilham J, Black SM. Asymmetric dimethylarginine inhibits HSP90 activity in pulmonary arterial endothelial cells: Role of mitochondrial dysfunction. Am J Physiol 294: C1407‐C1418, 2008.
 255. Sui H, Wang W, Wang PH, Liu LS. Effect of glutathione peroxidase mimic ebselen (PZ51) on endothelium and vascular structure of stroke‐prone spontaneously hypertensive rats. Blood Press 14: 366‐372, 2005.
 256. Sun X, Fratz S, Sharma S, Hou Y, Rafikov R, Kumar S, Rehmani I, Tian J, Smith A, Schreiber C, Reiser J, Naumann S, Haag S, Hess J, Catravas JD, Patterson C, Fineman JR, Black SM. C‐terminus of heat shock protein 70‐interacting protein‐dependent GTP cyclohydrolase I degradation in lambs with increased pulmonary blood flow. Am J Respir Cell Mol Biol 45: 163‐171, 2011.
 257. Sydow K, Munzel T. ADMA and oxidative stress. Atherosclerosis 4: 41‐51, 2003.
 258. Sylvester JT, Shimoda LA, Aaronson PI, Ward JP. Hypoxic pulmonary vasoconstriction. Physiol Rev 92: 367‐520, 2012.
 259. Takeya R, Sumimoto H. Regulation of novel superoxide‐producing NAD(P)H oxidases. Antioxid Redox Signal 8: 1523‐1532, 2006.
 260. Tate RM, Morris HG, Schroeder WR, Repine JE. Oxygen metabolites stimulate thromboxane production and vasoconstriction in isolated saline‐perfused rabbit lungs. J Clin Invest 74: 608‐613, 1984.
 261. Taylor DW, Wilson DW, Lame MW, Dunston SD, Jones AD, Segall HJ. Comparative cytotoxicity of monocrotaline and its metabolites in cultured pulmonary artery endothelial cells. Toxicol Appl Pharmacol 143: 196‐204, 1997.
 262. Teng RJ, Eis A, Bakhutashvili I, Arul N, Konduri GG. Increased superoxide production contributes to the impaired angiogenesis of fetal pulmonary arteries with in utero pulmonary hypertension. Am J Physiol 297: L184‐L195, 2009.
 263. Thannickal VJ, Day RM, Klinz SG, Bastien MC, Larios JM, Fanburg BL. Ras‐dependent and ‐independent regulation of reactive oxygen species by mitogenic growth factors and TGF‐beta1. Faseb J 14: 1741‐1748, 2000.
 264. Thannickal VJ, Fanburg BL. Activation of an H2O2‐generating NADH oxidase in human lung fibroblasts by transforming growth factor beta 1. J Biol Chem 270: 30334‐30338, 1995.
 265. Thannickal VJ, Fanburg BL. Reactive Oxygen Species in Cell Signaling. Am J Physiol lung Cell Mol Physiol 279 (6), L1005‐L1028, 2000.
 266. Thelitz S, Bekker JM, Ovadia B, Stuart RB, Johengen MJ, Black SM, Fineman JR. Inhaled nitric oxide decreases pulmonary soluble guanylate cyclase protein levels in 1‐month‐old lambs. J Thorac Cardiovasc Surg 127: 1285‐1292, 2004.
 267. Thibeault DW, Rezaiekhaligh M, Mabry S, Beringer T. Prevention of chronic pulmonary oxygen toxicity in young rats with liposome‐encapsulated catalase administered intratracheally. Pediatr Pulmonol 11: 318‐327, 1991.
 268. Thomas HC, Lame MW, Dunston SK, Segall HJ, Wilson DW. Monocrotaline pyrrole induces apoptosis in pulmonary artery endothelial cells. Toxicol Appl Pharmacol 151: 236‐244, 1998.
 269. Thomas HC, Lame MW, Wilson DW, Segall HJ. Cell cycle alterations associated with covalent binding of monocrotaline pyrrole to pulmonary artery endothelial cell DNA. Toxicol Appl Pharmacol 141: 319‐329, 1996.
 270. Touyz RM, Yao G, Schiffrin EL. c‐Src induces phosphorylation and translocation of p47phox: Role in superoxide generation by angiotensin II in human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 23: 981‐987, 2003.
 271. Tuder RM, Chacon M, Alger L, Wang J, Taraseviciene‐Stewart L, Kasahara Y, Cool CD, Bishop AE, Geraci M, Semenza GL, Yacoub M, Polak JM, Voelkel NF. Expression of angiogenesis‐related molecules in plexiform lesions in severe pulmonary hypertension: Evidence for a process of disordered angiogenesis. J Pathol 195: 367‐374, 2001.
 272. Tuder RM, Cool CD, Yeager M, Taraseviciene‐Stewart L, Bull TM, Voelkel NF. The pathobiology of pulmonary hypertension. Endothelium. Clin Chest Med 22: 405‐418, 2001.
 273. Tuder RM, Groves B, Badesch DB, Voelkel NF. Exuberant endothelial cell growth and elements of inflammation are present in plexiform lesions of pulmonary hypertension. Am J Pathol 144: 275‐285, 1994.
 274. Ushio‐Fukai M, Alexander RW, Akers M, Griendling KK. p38 Mitogen‐activated protein kinase is a critical component of the redox‐sensitive signaling pathways activated by angiotensin II. Role in vascular smooth muscle cell hypertrophy. J Biol Chem 273: 15022‐15029, 1998.
 275. Ushio‐Fukai M, Alexander RW, Akers M, Yin Q, Fujio Y, Walsh K, Griendling KK. Reactive oxygen species mediate the activation of Akt/protein kinase B by angiotensin II in vascular smooth muscle cells. J Biol Chem 274: 22699‐22704, 1999.
 276. Vásquez‐Vivar J, Kalyanaraman B, Martásek P, Hogg N, Masters BSS, Karoui H, Tordo P, Pritchard KA. Superoxide Generation by Endothelial Nitric Oxide Synthase: The Influence of Cofactors. Proc Natl Acad Sci U S A 95 (16): 9220‐9225, 1998.
 277. Valko M, Leibfritz D, Moncol J, Cronin MTD, Mazur M, Telser J. Free radicals and antioxidants in normal physiological functions and human disease. Int J Biochem Cell Biol 39: 44‐84, 2007.
 278. Valko M, Rhodes CJ, Moncol J, Izakovic M, Mazur M. Free radicals, metals and antioxidants in oxidative stress‐induced cancer. Chem Biol Interact 160: 1‐40, 2006.
 279. Van Rheen Z, Fattman C, Domarski S, Majka S, Klemm D, Stenmark KR, Nozik‐Grayck E. Lung extracellular superoxide dismutase overexpression lessens bleomycin‐induced pulmonary hypertension and vascular remodeling. Am J Respir Cell Mol Biol 44: 500‐508, 2011.
 280. Venditti CP, Harris MC, Huff D, Peterside I, Munson D, Weber HS, Rome J, Kaye EM, Shanske S, Sacconi S, Tay S, DiMauro S, Berry GT. Congenital cardiomyopathy and pulmonary hypertension: Another fatal variant of cytochrome‐c oxidase deficiency. J Inherit Metab Dis 27: 735‐739, 2004.
 281. Vignais PV. The superoxide‐generating NADPH oxidase: Structural aspects and activation mechanism. Cell Mol Life Sci 59: 1428‐1459, 2002.
 282. Voelkel NF, Tuder RM. Hypoxia‐induced pulmonary vascular remodeling: A model for what human disease? J Clin Invest 106: 733‐738, 2000.
 283. Wang D, Yu X, Cohen RA, Brecher P. Distinct effects of N‐acetylcysteine and nitric oxide on angiotensin II‐induced epidermal growth factor receptor phosphorylation and intracellular Ca(2+) levels. J Biol Chem 275: 12223‐12230, 2000.
 284. Wang J, Weigand L, Lu W, Sylvester JT, Semenza GL, Shimoda LA. Hypoxia inducible factor 1 mediates hypoxia‐induced TRPC expression and elevated intracellular Ca2+ in pulmonary arterial smooth muscle cells. Circ Res 98: 1528‐1537, 2006.
 285. Wang XT, McCullough KD, Wang XJ, Carpenter G, Holbrook NJ. Oxidative stress‐induced phospholipase C‐gamma 1 activation enhances cell survival. J Biol Chem 276: 28364‐28371, 2001.
 286. Wanstall JC, Gambino A, Jeffery TK, Cahill MM, Bellomo D, Hayward NK, Kay GF. Vascular endothelial growth factor‐B‐deficient mice show impaired development of hypoxic pulmonary hypertension. Cardiovasc Res 55: 361‐368, 2002.
 287. Wassmann S, Wassmann K, Nickenig G. Modulation of oxidant and antioxidant enzyme expression and function in vascular cells. Hypertension 44: 381‐386, 2004.
 288. Waypa GB, Chandel NS, Schumacker PT. Model for hypoxic pulmonary vasoconstriction involving mitochondrial oxygen sensing. Circ Res 88: 1259‐1266, 2001.
 289. Waypa GB, Marks JD, Guzy R, Mungai PT, Schriewer J, Dokic D, Schumacker PT. Hypoxia triggers subcellular compartmental redox signaling in vascular smooth muscle cells. Circ Res 106: 526‐535, 2010.
 290. Waypa GB, Marks JD, Mack MM, Boriboun C, Mungai PT, Schumacker PT. Mitochondrial reactive oxygen species trigger calcium increases during hypoxia in pulmonary arterial myocytes. Circ Res 91: 719‐726, 2002.
 291. Wedgwood S, Black SM. Induction of apoptosis in fetal pulmonary arterial smooth muscle cells by a combined superoxide dismutase/catalase mimetic. Am J Physiol 285: L305‐L312, 2003.
 292. Wedgwood S, Dettman RW, Black SM. ET‐1 stimulates pulmonary arterial smooth muscle cell proliferation via induction of reactive oxygen species. Am J Physiol 281: L1058‐L1067, 2001.
 293. Wedgwood S, Devol JM, Grobe A, Benavidez E, Azakie A, Fineman JR, Black SM. Fibroblast growth factor‐2 expression is altered in lambs with increased pulmonary blood flow and pulmonary hypertension. Pediatr Res 61: 32‐36, 2007.
 294. Wedgwood S, Lakshminrusimha S, Farrow KN, Czech L, Gugino SF, Soares F, Russell JA, Steinhorn RH. Apocynin improves oxygenation and increases eNOS in persistent pulmonary hypertension of the newborn. Am J Physiol 302: L616‐L626, 2012.
 295. Wedgwood S, Lakshminrusimha S, Fukai T, Russell JA, Schumacker PT, Steinhorn RH. Hydrogen peroxide regulates extracellular superoxide dismutase activity and expression in neonatal pulmonary hypertension. Antioxid Redox Signal 15: 1497‐1506, 2011.
 296. Wedgwood S, Steinhorn RH, Bunderson M, Wilham J, Lakshminrusimha S, Brennan LA, Black SM. Increased hydrogen peroxide downregulates soluble guanylate cyclase in the lungs of lambs with persistent pulmonary hypertension of the newborn. Am J Physiol 289: L660‐L666, 2005.
 297. Weissmann N, Winterhalder S, Nollen M, Voswinckel R, Quanz K, Ghofrani HA, Schermuly RT, Seeger W, Grimminger F. NO and reactive oxygen species are involved in biphasic hypoxic vasoconstriction of isolated rabbit lungs. Am J Physiol 280: L638‐L645, 2001.
 298. Wilcken DE, Sim AS, Wang J, Wang XL. Asymmetric dimethylarginine (ADMA) in vascular, renal and hepatic disease and the regulatory role of L‐arginine on its metabolism. Mol Genet Metab 91: 309‐317; discussion 308, 2007.
 299. Wilson DW, Segall HJ, Pan LC, Lame MW, Estep JE, Morin D. Mechanisms and pathology of monocrotaline pulmonary toxicity. Crit Rev Toxicol 22: 307‐325, 1992.
 300. Wright L, Tuder RM, Wang J, Cool CD, Lepley RA, Voelkel NF. 5‐Lipoxygenase and 5‐lipoxygenase activating protein (FLAP) immunoreactivity in lungs from patients with primary pulmonary hypertension. Am J Respir Crit Care Med 157: 219‐229, 1998.
 301. Xu D, Guo H, Xu X, Lu Z, Fassett J, Hu X, Xu Y, Tang Q, Hu D, Somani A, Geurts AM, Ostertag E, Bache RJ, Weir EK, Chen Y. Exacerbated pulmonary arterial hypertension and right ventricular hypertrophy in animals with loss of function of extracellular superoxide dismutase. Hypertension 58: 303‐309, 2011.
 302. Xu W, Koeck T, Lara AR, Neumann D, DiFilippo FP, Koo M, Janocha AJ, Masri FA, Arroliga AC, Jennings C, Dweik RA, Tuder RM, Stuehr DJ, Erzurum SC. Alterations of cellular bioenergetics in pulmonary artery endothelial cells. Proc Natl Acad Sci U S A 104: 1342‐1347, 2007.
 303. Yamagishi S, Imaizumi T. Pericyte biology and diseases. Int J Tissue React 27: 125‐135, 2005.
 304. Yeager ME, Golpon HA, Voelkel NF, Tuder RM. Microsatellite mutational analysis of endothelial cells within plexiform lesions from patients with familial, pediatric, and sporadic pulmonary hypertension. Chest 121: 61S, 2002.
 305. Yeager ME, Halley GR, Golpon HA, Voelkel NF, Tuder RM. Microsatellite instability of endothelial cell growth and apoptosis genes within plexiform lesions in primary pulmonary hypertension. Circ Res 88: E2‐E11, 2001.
 306. Yi ES, Kim H, Ahn H, Strother J, Morris T, Masliah E, Hansen LA, Park K, Friedman PJ. Distribution of obstructive intimal lesions and their cellular phenotypes in chronic pulmonary hypertension. A morphometric and immunohistochemical study. Am J Respir Crit Care Med 162: 1577‐1586, 2000.
 307. Yokoyama M, Hirata K. Endothelial nitric oxide synthase uncoupling: Is it a physiological mechanism of endothelium‐dependent relaxation in cerebral artery? Cardiovasc Res 73: 8‐9, 2007.
 308. Yoshizumi M, Abe J, Haendeler J, Huang Q, Berk BC. Src and Cas mediate JNK activation but not ERK1/2 and p38 kinases by reactive oxygen species. J Biol Chem 275: 11706‐11712, 2000.
 309. Yuan JX, Aldinger AM, Juhaszova M, Wang J, Conte JV, Jr., Gaine SP, Orens JB, Rubin LJ. Dysfunctional voltage‐gated K+ channels in pulmonary artery smooth muscle cells of patients with primary pulmonary hypertension. Circulation 98: 1400‐1406, 1998.
 310. Zalewski A, Shi Y. Vascular myofibroblasts. Lessons from coronary repair and remodeling. Arterioscler Thromb Vasc Biol 17: 417‐422, 1997.
 311. Zamora MR, Stelzner TJ, Webb S, Panos RJ, Ruff LJ, Dempsey EC. Overexpression of endothelin‐1 and enhanced growth of pulmonary artery smooth muscle cells from fawn‐hooded rats. Am J Physiol 270: L101‐L109, 1996.

Related Articles:

Endothelial and Smooth Muscle Cell Ion Channels in Pulmonary Vasoconstriction and Vascular Remodeling
Endothelial Cell Energy Metabolism, Proliferation, and Apoptosis in Pulmonary Hypertension
Experimental and Transgenic Models of Pulmonary Hypertension
Pulmonary Vascular Disease

Contact Editor

Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite

Saurabh Aggarwal, Christine M. Gross, Shruti Sharma, Jeffrey R. Fineman, Stephen M. Black. Reactive Oxygen Species in Pulmonary Vascular Remodeling. Compr Physiol 2013, 3: 1011-1034. doi: 10.1002/cphy.c120024