Pulmonary Vascular Remodeling Associated with Chronic Smoking, COPD, and Group III Pulmonary Hypertension

Chronic hypoxia induces lung vascular remodeling, which results in pulmonary hypertension. We hypothesized that a previously found increase in collagenolytic activity of matrix metalloproteinases during hypoxia promotes pulmonary vascular remodeling and hypertension. To test this hypothesis, we exposed rats to hypoxia (fraction of inspired oxygen = 0.1, 3 wk) and treated them with a metalloproteinase inhibitor, Batimastat (30 mg/kg body wt, daily ip injection). Hypoxia-induced increases in concentration of collagen breakdown products and in collagenolytic activity in pulmonary vessels were inhibited by Batimastat, attesting to the effectiveness of Batimastat administration. Batimastat markedly reduced hypoxic pulmonary hypertension: pulmonary arterial blood pressure was 32 ± 3 mmHg in hypoxic controls, 24 ± 1 mmHg in Batimastat-treated hypoxic rats, and 16 ± 1 mmHg in normoxic controls. Right ventricular hypertrophy and muscularization of peripheral lung vessels were also diminished. Batimastat had no influence on systemic arterial pressure or cardiac output and was without any effect in rats kept in normoxia. We conclude that stimulation of collagenolytic activity in chronic hypoxia is a substantial causative factor in the pathogenesis of pulmonary vascular remodeling and hypertension.

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

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00238.2014 ◽

2015 ◽

Vol 308 (3) ◽

pp. L229-L252 ◽

Cited By ~ 88

Author(s):

Steven C. Pugliese ◽

Jens M. Poth ◽

Mehdi A. Fini ◽

Andrea Olschewski ◽

Karim C. El Kasmi ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Signaling Pathways ◽

Vascular Remodeling ◽

Mesenchymal Cells ◽

World Health ◽

Small Subset ◽

Cellular Interactions ◽

Pulmonary Vascular Remodeling ◽

Hypoxic Pulmonary Hypertension ◽

Group I

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

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Pulmonary vascular remodeling and pathobiology of pulmonary hypertension

Pulmonary Circulation, 3rd edition ◽

10.1201/b13219-8 ◽

2011 ◽

pp. 59-77 ◽

Cited By ~ 1

Author(s):

Nicholas Morrell

Keyword(s):

Pulmonary Hypertension ◽

Vascular Remodeling ◽

Pulmonary Vascular Remodeling

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Calcium antagonists, diltiazem and nifedipine, protect broilers against low temperature-induced pulmonary hypertension and pulmonary vascular remodeling

Animal Science Journal ◽

10.1111/j.1740-0929.2010.00762.x ◽

2010 ◽

Vol 81 (4) ◽

pp. 494-500 ◽

Cited By ~ 7

Author(s):

Ying YANG ◽

Mingyu GAO ◽

Yuming GUO ◽

Jian QIAO

Keyword(s):

Pulmonary Hypertension ◽

Low Temperature ◽

Calcium Antagonists ◽

Vascular Remodeling ◽

Pulmonary Vascular Remodeling

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HIF2α–arginase axis is essential for the development of pulmonary hypertension

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1602978113 ◽

2016 ◽

Vol 113 (31) ◽

pp. 8801-8806 ◽

Cited By ~ 70

Author(s):

Andrew S. Cowburn ◽

Alexi Crosby ◽

David Macias ◽

Cristina Branco ◽

Renato D. D. R. Colaço ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Vascular Remodeling ◽

Hypoxic Pulmonary Vasoconstriction ◽

Systolic Pressure ◽

Hypoxic Exposure ◽

Pulmonary Vascular Remodeling ◽

Ventricular Systolic Pressure ◽

Pulmonary Endothelium ◽

Arginase 1

Hypoxic pulmonary vasoconstriction is correlated with pulmonary vascular remodeling. The hypoxia-inducible transcription factors (HIFs) HIF-1α and HIF-2α are known to contribute to the process of hypoxic pulmonary vascular remodeling; however, the specific role of pulmonary endothelial HIF expression in this process, and in the physiological process of vasoconstriction in response to hypoxia, remains unclear. Here we show that pulmonary endothelial HIF-2α is a critical regulator of hypoxia-induced pulmonary arterial hypertension. The rise in right ventricular systolic pressure (RVSP) normally observed following chronic hypoxic exposure was absent in mice with pulmonary endothelial HIF-2α deletion. The RVSP of mice lacking HIF-2α in pulmonary endothelium after exposure to hypoxia was not significantly different from normoxic WT mice and much lower than the RVSP values seen in WT littermate controls and mice with pulmonary endothelial deletion of HIF-1α exposed to hypoxia. Endothelial HIF-2α deletion also protected mice from hypoxia remodeling. Pulmonary endothelial deletion of arginase-1, a downstream target of HIF-2α, likewise attenuated many of the pathophysiological symptoms associated with hypoxic pulmonary hypertension. We propose a mechanism whereby chronic hypoxia enhances HIF-2α stability, which causes increased arginase expression and dysregulates normal vascular NO homeostasis. These data offer new insight into the role of pulmonary endothelial HIF-2α in regulating the pulmonary vascular response to hypoxia.

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Hypoxia-Induced Changes in the Mechanical Properties of the Mouse Pulmonary Artery

Advances in Bioengineering ◽

10.1115/imece2003-43086 ◽

2003 ◽

Author(s):

Ryan W. Kobs ◽

Nidal E. Muvarak ◽

Naomi C. Chesler

Keyword(s):

Mechanical Properties ◽

Pulmonary Hypertension ◽

Pulmonary Artery ◽

Vascular Remodeling ◽

Hypobaric Hypoxia ◽

Vessel Wall ◽

Main Pulmonary Artery ◽

Collagen Content ◽

Pulmonary Vascular Remodeling ◽

Induced Changes

Hypobaric hypoxia produces pulmonary hypertension in mice which causes pulmonary vascular remodeling. To study the biomechanics of this process, mice were exposed to hypoxia for 0-(control), 10-, and 15-days. Using a pressurized arteriograph system, mechanical properties of the main pulmonary artery were measured and compared to the biological changes in the vessel wall measured histologically. 10- and 15-day hypoxic vessels were significantly stiffer when compared to 0-day vessels. This stiffness correlated with greater elastin and collagen content in the vessel wall.

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