Comparative physiology of hypoxic pulmonary hypertension: historical clues from brisket disease

2005 ◽  
Vol 98 (3) ◽  
pp. 1092-1100 ◽  
Author(s):  
Jann Rhodes
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Chronic Hypoxia ◽  
Splice Variants ◽  
Pulmonary Arteries ◽  
High Mountain ◽  
Hypoxic Pulmonary Hypertension ◽  
And Gender ◽  
Medial Hypertrophy

Some of the most valuable contributions to science have come about serendipitously, and, in 1913, when George Glover and Issac Newsom were commissioned by Colorado cattle ranchers to study high mountain disease, there was no way to anticipate the tremendous impact they would have on the study of high-altitude cardiopulmonary physiology. It was through the study of this agricultural malady that the correlation between chronic hypoxia, pulmonary hypertension, medial hypertrophy of the small pulmonary arteries, and right ventricular (RV) hypertrophy was recognized. The amount of vascular smooth muscle comprising the medial layer of pulmonary arteries varies significantly across species and can be used to predict the magnitude of pulmonary hypertension and RV hypertrophy elicited in response to chronic hypoxia. Within species, age and gender both significantly influence the severity of chronic hypoxic pulmonary hypertension and RV hypertrophy. However, despite all that we now know about hypoxic pulmonary hypertension, the specific mechanism(s) that differentiate the hypo- from the hyperresponder have yet to be elucidated. Adventitial fibroblast differentiation, circulating vascular progenitor cells, the presence or absence of specific vascular smooth muscle phenotypes, the upregulation or downregulation of vasoactive mediators, splice variants of oxygen-sensitive transcription factors, upregulation of growth factors, Ca2+ sensitization, and/or the Rho/Rho-kinases signaling cascade could all potentially play a role in determining the extent of the vascular response to hypoxia within a species. Understanding the mechanisms that determine why some people, as well as some animals, exhibit a marked susceptibility to hypoxia is an important endeavor with far-reaching implications.

scholarly journals Chronic hypoxia augments depolarization-induced Ca2+ sensitization in pulmonary vascular smooth muscle through superoxide-dependent stimulation of RhoA

2010 ◽  
Vol 298 (2) ◽  
pp. L232-L242 ◽  
Author(s):  
Brad R. S. Broughton ◽  
Nikki L. Jernigan ◽  
Charles E. Norton ◽  
Benjimen R. Walker ◽  
Thomas C. Resta
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Rho Kinase ◽  
Membrane Depolarization ◽  
Dependent Manner ◽  
Rock Inhibitor ◽  
Rhoa Activation

Rho kinase (ROCK)-dependent vasoconstriction has been implicated as a major factor in chronic hypoxia (CH)-induced pulmonary hypertension. This component of pulmonary hypertension is associated with arterial myogenicity and increased vasoreactivity to receptor-mediated agonists and depolarizing stimuli resulting from ROCK-dependent myofilament Ca2+ sensitization. On the basis of separate lines of evidence that CH increases pulmonary arterial superoxide (O2−) generation and that O2− stimulates RhoA/ROCK signaling in vascular smooth muscle (VSM), we hypothesized that depolarization-induced O2− generation mediates enhanced RhoA-dependent Ca2+ sensitization in pulmonary VSM following CH. To test this hypothesis, we determined effects of the ROCK inhibitor HA-1077 and the O2−-specific spin trap tiron on vasoconstrictor reactivity to depolarizing concentrations of KCl in isolated lungs and Ca2+-permeabilized, pressurized small pulmonary arteries from control and CH (4 wk at 0.5 atm) rats. Using the same vessel preparation, we examined effects of CH on KCl-dependent VSM membrane depolarization and O2− generation using sharp electrodes and the fluorescent indicator dihydroethidium, respectively. Finally, using a RhoA-GTP pull-down assay, we investigated the contribution of O2− to depolarization-induced RhoA activation. We found that CH augmented KCl-dependent vasoconstriction through a Ca2+ sensitization mechanism that was inhibited by HA-1077 and tiron. Furthermore, CH caused VSM membrane depolarization that persisted with increasing concentrations of KCl, enhanced KCl-induced O2− generation, and augmented depolarization-dependent RhoA activation in a O2−-dependent manner. These findings reveal a novel mechanistic link between VSM membrane depolarization, O2− generation, and RhoA activation that mediates enhanced myofilament Ca2+ sensitization and pulmonary vasoconstriction following CH.

scholarly journals Deletion of STAT5a/b in Vascular Smooth Muscle Abrogates the Male Bias in Hypoxic Pulmonary Hypertension in Mice: Implications in the Human Disease

2014 ◽  
Vol 20 (1) ◽  
pp. 625-638 ◽  
Author(s):  
Yang-Ming Yang ◽  
Huijuan Yuan ◽  
John G. Edwards ◽  
Yester Skayian ◽  
Kanta Ochani ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Human Disease ◽  
Hypoxic Pulmonary Hypertension ◽  
Male Bias

scholarly journals Regulation of soluble guanylyl cyclase-α1 expression in chronic hypoxia-induced pulmonary hypertension: role of NFATc3 and HuR

2009 ◽  
Vol 297 (3) ◽  
pp. L475-L486 ◽  
Author(s):  
Sergio de Frutos ◽  
Carlos H. Nitta ◽  
Elizabeth Caldwell ◽  
Jessica Friedman ◽  
Laura V. González Bosc
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Guanylyl Cyclase ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Soluble Guanylyl Cyclase ◽  
Muscle Cells ◽  
Pulmonary Artery Smooth Muscle

The nitric oxide/soluble guanylyl cyclase (sGC) signal transduction pathway plays an important role in smooth muscle relaxation and phenotypic regulation. However, the transcriptional regulation of sGC gene expression is largely unknown. It has been shown that sGC expression increases in pulmonary arteries from chronic hypoxia-induced pulmonary hypertensive animals. Since the transcription factor NFATc3 is required for the upregulation of the smooth muscle hypertrophic/differentiation marker α-actin in pulmonary artery smooth muscle cells from chronically hypoxic mice, we hypothesized that NFATc3 is required for the regulation of sGC-α1 expression during chronic hypoxia. Exposure to chronic hypoxia for 2 days induced a decrease in sGC-α1 expression in mouse pulmonary arteries. This reduction was independent of NFATc3 but mediated by nuclear accumulation of the mRNA-stabilizing protein human antigen R (HuR). Consistent with our hypothesis, chronic hypoxia (21 days) upregulated pulmonary artery sGC-α1 expression, bringing it back to the level of the normoxic controls. This response was prevented in NFATc3 knockout and cyclosporin (calcineurin/NFATc inhibitor)-treated mice. Furthermore, we identified effective binding sites for NFATc in the mouse sGC-α1 promoter. Activation of NFATc3 increased sGC-α1 promoter activity in human embryonic derived kidney cells, rat aortic-derived smooth muscle cells, and human pulmonary artery smooth muscle cells. Our results suggest that NFATc3 and HuR are important regulators of sGC-α1 expression in pulmonary vascular smooth muscle cells during chronic hypoxia-induced pulmonary hypertension.

scholarly journals Severe asthma is associated with a remodeling of the pulmonary arteries in horses

2020 ◽  
Author(s):  
Serena Ceriotti ◽  
Michela Bullone ◽  
Mathilde Leclere ◽  
Francesco Ferrucci ◽  
Jean-Pierre Lavoie
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Muscle Mass ◽  
Pulmonary Arteries ◽  
Chronic Obstructive ◽  
Corticosteroid Administration ◽  
Wall Area ◽  
Hypoxic Vasoconstriction ◽  
Equine Asthma

AbstractPulmonary hypertension and cor pulmonale are complications of severe equine asthma, as a consequence of pulmonary hypoxic vasoconstriction. However, as pulmonary hypertension is only partially reversible by oxygen administration, other etiological factors are likely involved. In human chronic obstructive pulmonary disease, pulmonary artery remodeling contributes to the development of pulmonary hypertension. In rodent models, pulmonary vascular remodeling is present as a consequence of allergic airway inflammation. The present study investigated the presence of remodeling of the pulmonary arteries in severe equine asthma, its distribution throughout the lungs, and its reversibility following long-term antigen avoidance strategies and inhaled corticosteroid administration. Using histomorphometry, the total wall area of pulmonary arteries from different regions of the lung of asthmatic horses and controls was measured. The smooth muscle mass of pulmonary arteries was also estimated on lung sections stained for α-smooth muscle actin. Reversibility of vascular changes in asthmatic horses was assessed after 1 year of antigen avoidance alone or treatment with inhaled fluticasone. Pulmonary arteries showed increased wall area in apical and caudodorsal lung regions of asthmatic horses in both exacerbation and remission. The pulmonary arteries smooth muscle mass was similarly increased. Both treatments reversed the increase in wall area. However, normalization of the vascular smooth muscle mass was observed only after treatment with antigen avoidance, but not with fluticasone. In conclusion, severe equine asthma is associated with remodeling of the pulmonary arteries consisting in an increased smooth muscle mass. The resulting narrowing of the artery lumen could enhance hypoxic vasoconstriction, contributing to pulmonary hypertension. Vascular smooth muscle mass normalization is better achieved by antigen avoidance than with inhaled corticosteroids.

Cellular adaptation during chronic neonatal hypoxic pulmonary hypertension

1991 ◽  
Vol 261 (4) ◽  
pp. L97-L104 ◽  
Author(s):  
Kurt R. Stenmark ◽  
Almas A. Aldashev ◽  
Ernest C. Orton ◽  
A. G. Durmowicz ◽  
D. B. Badesch ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Arterial Wall ◽  
Chronic Hypoxia ◽  
Left Pulmonary Artery ◽  
Right Atrial ◽  
Vascular Changes ◽  
Hypoxic Pulmonary Hypertension

Newbor animals develop more severe hypoxic pulmonary hypertension than do adults, their vascular changes are greater, and both the hypertension and vascular changes occur more rapidly. We hypothesize that this differential developmentally controlled response may arise from either a difference in the type or quantity of endogenously secreted mediators in response to a given injury or a difference in the replicative and/or matrix-producing response of the vascular cells to physical or chemical stimuli. We investigated the effect of chronic hypoxia (14 days) on the proliferative and matrix-producing phenotype of the neonatal (14-day-old) pulmonary artery smooth muscle cell (SMC) and examined the heterogeneity and potential mechanisms responsible for this response. In situ hybridization studies demonstrated a remarkable change in the distribution of cells hybridizing with a tropoelastin cRNA probe after 14 days of hypoxia. Studies also demonstrated a population of SMC that did not hybridize with the elastin or collagen probes, indicating that the pulmonary artery contains SMC of multiple phenotypes and that the response to hypoxic and hemodynamic stress is not uniform for the various types. Bromodeoxyuridine labeling experiments indicated a large increase in DNA synthesis in hypertensive vessels, which, again, was not uniform either across or along the arterial wall. In vitro experiments with neonatal SMC suggested that hypoxia alone could not be responsible for the proliferative or matrix changes. These observations were supported by in vivo experiments in which coarctation of the left pulmonary artery, which markedly decreased pressure and flow to the left lung in hypoxic animals (14 days), resulted in significant decreases in collagen and elastin message levels in the left pulmonary artery distal to the coarctation compared with location-matched vessels from the right lung. Finally, we noted marked decreases in B-receptor density and adenyl cyclase activity in right atrial and pulmonary artery tissue from the chronically hypoxic animals. Decreases in the ability of the cell to produce adenosine 3',5'-cyclic monophosphate could significantly affect both the proliferative and matrix-producing potential of the SMC. We conclude that in vivo adaptation of the pulmonary artery SMC to chronic hypoxia includes changes in protein synthesis, cell proliferation, receptor expression, and enzyme activity. Further, there is a marked heterogeneity of these responses both across and along the arterial wall. hypoxia; phenotype; signal transductions; smooth muscle cells

Pulmonary hypertension is attenuated and ventilation-perfusion matching is maintained during chronic hypoxia in deer mice native to high altitude

2021 ◽  
Author(s):  
Claire M. West ◽  
Oliver H. Wearing ◽  
Rod G. Rhem ◽  
Graham R. Scott
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Right Ventricle ◽  
High Altitude ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Deer Mice ◽  
Maladaptive Response ◽  
Ventricle Hypertrophy ◽  
Right Ventricle Hypertrophy

Hypoxia at high altitude can constrain metabolism and performance, and can elicit physiological adjustments that are deleterious to health and fitness. Hypoxic pulmonary hypertension is a particularly serious and maladaptive response to chronic hypoxia, which results from vasoconstriction and pathological remodeling of pulmonary arteries, and can lead to pulmonary edema and right ventricle hypertrophy. We investigated whether deer mice (Peromyscus maniculatus) native to high altitude have attenuated this maladaptive response to chronic hypoxia, and whether evolved changes or hypoxia-induced plasticity in pulmonary vasculature might impact ventilation-perfusion (V-Q) matching in chronic hypoxia. Deer mouse populations from both high and low altitudes were born and raised to adulthood in captivity at sea level, and various aspects of lung function were measured before and after exposure to chronic hypoxia (12 kPa O2, simulating the O2 pressure at 4300 m) for 6-8 weeks. In lowlanders, chronic hypoxia increased right ventricle systolic pressure (RVSP) from 14 to 19 mmHg (P = 0.001), in association with thickening of smooth muscle in pulmonary arteries and right ventricle hypertrophy. Chronic hypoxia also impaired V-Q matching in lowlanders (measured at rest using SPECT-CT imaging), as reflected by increased log SD of the perfusion distribution (log SDQ) from 0.55 to 0.86 (P = 0.031). In highlanders, chronic hypoxia had attenuated effects on RVSP and no effects on smooth muscle thickness, right ventricle mass, or V-Q matching. Therefore, evolved changes in lung function help attenuate maladaptive plasticity and contribute to hypoxia tolerance in high-altitude deer mice.

Impaired NO-dependent inhibition of store- and receptor-operated calcium entry in pulmonary vascular smooth muscle after chronic hypoxia

2006 ◽  
Vol 290 (3) ◽  
pp. L517-L525 ◽  
Author(s):  
Nikki L. Jernigan ◽  
Brad R. S. Broughton ◽  
Benjimen R. Walker ◽  
Thomas C. Resta
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Chronic Hypoxia ◽  
Pulmonary Arteries ◽  
Cyclopiazonic Acid ◽  
Free Calcium ◽  
No Donor ◽  
Dependent Inhibition ◽  
Intracellular Ca ◽  
Spermine Nonoate

We have recently demonstrated that chronic hypoxia (CH) attenuates nitric oxide (NO)-mediated decreases in pulmonary vascular smooth muscle (VSM) intracellular free calcium concentration ([Ca2+]i) and promotes NO-dependent VSM Ca2+ desensitization. The objective of the current study was to identify potential mechanisms by which CH interferes with regulation of [Ca2+]i by NO. We hypothesized that CH impairs NO-mediated inhibition of store-operated (capacitative) Ca2+ entry (SOCE) or receptor-operated Ca2+ entry (ROCE) in pulmonary VSM. To test this hypothesis, we examined effects of the NO donor, spermine NONOate, on SOCE resulting from depletion of intracellular Ca2+ stores with cyclopiazonic acid, and on UTP-induced ROCE in isolated, endothelium-denuded, pressurized pulmonary arteries (213 ± 8 μm inner diameter) from control and CH (4 wk at 0.5 atm) rats. Arteries were loaded with fura-2 AM to continuously monitor VSM [Ca2+]i. We found that the change in [Ca2+]i associated with SOCE and ROCE was significantly reduced in vessels from CH animals. Furthermore, spermine NONOate diminished SOCE and ROCE in vessels from control, but not CH animals. We conclude that NO-mediated inhibition of SOCE and ROCE is impaired after CH-induced pulmonary hypertension.

Effect of dietary fish oil on lung lipid profile and hypoxic pulmonary hypertension

1989 ◽  
Vol 66 (4) ◽  
pp. 1662-1673 ◽  
Author(s):  
S. L. Archer ◽  
G. J. Johnson ◽  
R. L. Gebhard ◽  
W. L. Castleman ◽  
A. S. Levine ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Fish Oil ◽  
Chronic Hypoxia ◽  
Corn Oil ◽  
Pulmonary Arteries ◽  
Hypoxic Pulmonary Hypertension ◽  
Dietary Fish ◽  
Lung Lipid ◽  
Pulmonary Arterial ◽  
Fish Oil Diet

The effects of dietary polyunsaturated fats on chronic hypoxic pulmonary hypertension were assessed in rats fed fish oil, corn oil, or a lower fat, “high-carbohydrate” diet (regular) beginning 1 mo before the start of hypoxia (0.4 atm, n = 30 for each). Mean pulmonary arterial pressures were lower in the chronically hypoxic rats fed fish oil (19.7 +/- 1.8 mm Hg) than in the rats fed corn oil (25.3 +/- 1.6 mm Hg) or regular diets (27.5 +/- 1.5 mm Hg, P less than 0.05). The fish oil diet increased lung eicosapentaenoic acid 50-fold and depleted lung arachidonic acid 60% (P less than 0.0001 for each). Lung thromboxane B2 and 6-ketoprostaglandin F1 alpha levels were lower, and platelet aggregation, in response to collagen, was reduced in rats fed fish oil. Chronically hypoxic rats fed fish oil had lower mortality rates than the other hypoxic rats. They also had lower blood viscosity, as well as less right ventricular hypertrophy and less peripheral extension of vascular smooth muscle to intra-acinar pulmonary arteries (P less than 0.05 for each). The mechanism by which dietary fish oil decreases pulmonary hypertension and vascular remodeling during chronic hypoxia remains uncertain. The finding that a fish oil diet can reduce the hemodynamic and morphological sequelae of chronic hypoxia may have therapeutic significance.

Cellular adaptation during chronic neonatal hypoxic pulmonary hypertension

1991 ◽  
Vol 261 (4) ◽  
pp. 97-104 ◽  
Author(s):  
Kurt R. Stenmark ◽  
Almas A. Aldashev ◽  
Ernest C. Orton ◽  
A. G. Durmowicz ◽  
D. B. Badesch ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Arterial Wall ◽  
Chronic Hypoxia ◽  
Left Pulmonary Artery ◽  
Right Atrial ◽  
Vascular Changes ◽  
Hypoxic Pulmonary Hypertension

Newborn animals develop more severe hypoxic pulmonary hypertension than do adults, their vascular changes are greater, and both the hypertension and vascular changes occur more rapidly. We hypothesize that this differential developmentally controlled response may arise from either a difference in the type or quantity of endogenously secreted mediators in response to a given injury or a difference in the replicative and/or matrix-producing response of the vascular cells to physical or chemical stimuli. We investigated the effect of chronic hypoxia (14 days) on the proliferative and matrix-producing phenotype of the neonatal (14-day-old) pulmonary artery smooth muscle cell (SMC) and examined the heterogeneity and potential mechanisms responsible for this response. In situ hybridization studies demonstrated a remarkable change in the distribution of cells hybridizing with a tropoelastin cRNA probe after 14 days of hypoxia. Studies also demonstrated a population of SMC that did not hybridize with the elastin or collagen probes, indicating that the pulmonary artery contains SMC of multiple phenotypes and that the response to hypoxic and hemodynamic stress is not uniform for the various types. Bromodeoxyuridine labeling experiments indicated a large increase in DNA synthesis in hypertensive vessels, which, again, was not uniform either across or along the arterial wall. In vitro experiments with neonatal SMC suggested that hypoxia alone could not be responsible for the proliferative or matrix changes. These observations were supported by in vivo experiments in which coarctation of the left pulmonary artery, which markedly decreased pressure and flow to the left lung in hypoxic animals (14 days), resulted in significant decreases in collagen and elastin message levels in the left pulmonary artery distal to the coarctation compared with location-matched vessels from the right lung. Finally, we noted marked decreases in B-receptor density and adenyl cyclase activity in right atrial and pulmonary artery tissue from the chronically hypoxic animals. Decreases in the ability of the cell to produce adenosine 3',5'-cyclic monophosphate could significantly affect both the proliferative and matrix-producing potential of the SMC. We conclude that in vivo adaptation of the pulmonary artery SMC to chronic hypoxia includes changes in protein synthesis, cell proliferation, receptor expression, and enzyme activity. Further, there is a marked heterogeneity of these responses both across and along the arterial wall., hypoxia; phenotype; signal transductions; smooth muscle cells

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