Pulmonary hypertension and increased vasoreactivity caused by repeated indomethacin in sheep

1985 ◽  
Vol 59 (2) ◽  
pp. 443-452 ◽  
Author(s):  
B. Meyrick ◽  
M. E. Niedermeyer ◽  
M. L. Ogletree ◽  
K. L. Brigham
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arteries ◽  
Blood Gases ◽  
Repeated Administration ◽  
Base Line ◽  
External Diameter ◽  
Arterial Circulation ◽  
Peripheral Lung ◽  
Chronic Pulmonary Hypertension ◽  
Pulmonary Arterial

Six chronically catheterized awake sheep were given the cyclooxygenase inhibitor indomethacin (5 mg/kg) twice a day over a 3-wk period. Three sheep receiving vehicle alone served as controls. Pulmonary arterial, left atrial, and systemic arterial pressures, cardiac output, blood gases, and pH were measured biweekly. Pulmonary vasoreactivity to 12% O2 and an analogue of prostaglandin H2 (PGH2-A) was also assessed. As a percent of base line, indomethacin caused a doubling in pulmonary vascular resistance (3 wk = 190 +/- 26%, mean +/- SE) and a 50% increase in pulmonary arterial pressure (3 wk = 151 +/- 9%). Vasoreactivity to 12% O2 increased approximately fourfold during the 1st wk of treatment and then declined. Vasoreactivity to PGH2-A increased steadily, nearly doubling by 3 wk. Light-microscopic counts of peripheral lung biopsy tissue revealed marked sequestration of granulocytes. Morphometric techniques applied to lungs removed at autopsy and fixed with the pulmonary arteries distended with barium gelatin mixture showed a significant reduction in number of barium-filled peripheral arteries and reduction in their external diameter. We conclude that repeated administration of indomethacin alters pulmonary vasoreactivity and causes sustained pulmonary hypertension. Structural studies reveal peripheral lung inflammation and changes in the arterial circulation that are perhaps more consistent with maintained vasoconstriction than chronic pulmonary hypertension.

Increased vasoreactivity and chronic pulmonary hypertension following thoracic irradiation in sheep

1986 ◽  
Vol 61 (5) ◽  
pp. 1875-1881 ◽  
Author(s):  
E. A. Perkett ◽  
K. L. Brigham ◽  
B. Meyrick
Keyword(s):  
Pulmonary Hypertension ◽  
Vascular Reactivity ◽  
Structural Changes ◽  
Blood Gases ◽  
Base Line ◽  
External Diameter ◽  
Thoracic Irradiation ◽  
Arterial Blood ◽  
Chronic Pulmonary Hypertension ◽  
Pulmonary Arterial

Six chronically catheterized sheep were exposed to 1,500-rad whole-lung irradiation and followed for a four-week period. Pulmonary arterial, left atrial and systemic arterial pressures, cardiac output, arterial blood gases, and pH were measured at base line and biweekly following radiation. Pulmonary vasoreactivity to 12% O2, 100% O2, and an analogue of prostaglandin H2 (PGH2-A) was also assessed. Five nonirradiated sheep served as controls. By the 2nd wk following irradiation, pulmonary vascular resistance had doubled. Final pulmonary arterial pressure was increased 50% over the base-line value (base line = 14 +/- 1 cm H2O; final 22 +/- 2; mean +/- SE; P less than 0.05). Arterial PO2 was decreased to approximately 70 Torr throughout the study. In addition, pulmonary vasoreactivity to PGH2-A, but not to breathing 12 or 100% O2, was significantly increased above base line in the irradiated animals (P less than 0.05). Morphometric techniques applied to the lungs in which the pulmonary arterial circulation was distended with barium gelatin mixture, showed extension of muscle into the distal intra-acinar arteries, and a reduction in both the external diameter and the number of barium-filled peripheral arteries in the irradiated animals. Thus thoracic irradiation results in functional and structural changes of chronic pulmonary hypertension and increased pulmonary vasoreactivity to PGH2-A. The structural changes in the peripheral pulmonary arterial bed may contribute to the increased pulmonary vascular reactivity following thoracic irradiation.

Secretory leukoprotease inhibitor attenuates lung injury induced by continuous air embolization into sheep

1995 ◽  
Vol 79 (4) ◽  
pp. 1163-1172 ◽  
Author(s):  
J. R. Gossage ◽  
E. A. Perkett ◽  
J. M. Davidson ◽  
B. C. Starcher ◽  
D. Carmichael ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Neutrophil Elastase ◽  
Serine Proteases ◽  
Structural Changes ◽  
Pulmonary Arteries ◽  
Neutrophil Elastase Inhibitor ◽  
Elastase Inhibitor ◽  
Arterial Circulation ◽  
Chronic Pulmonary Hypertension ◽  
Lung Lymph

Continuous air embolization (CAE) into the pulmonary arterial circulation of sheep results in functional and structural changes of chronic pulmonary hypertension. Release of elastin peptides into lung lymph during CAE and attenuation of CAE-induced pulmonary hypertension by neutrophil depletion suggest that neutrophil elastase may contribute to these changes. To investigate this notion, we treated awake sheep with a potent neutrophil elastase inhibitor, recombinant secretory leukoprotease inhibitor (SLPI) (100 mg/day by aerosol), during 12 days of CAE (CAE+SLPI; n = 7). Controls included sheep receiving CAE + vehicle (VEH) (n = 6), VEH alone (n = 3), and SLPI alone (n = 3). SLPI significantly attenuated the CAE-induced increases in lung lymph flow (day 8; 2.3 +/- 0.5 vs. 5.6 +/- 1.7 ml/15 min), protein clearance (day 8; 1.36 +/- 0.32 vs. 3.08 +/- 0.84 ml/15 min), and elastin peptide concentration (day 8; 243 +/- 41 vs. 398 +/- 44 ng/ml). SLPI delayed the onset of sustained pulmonary hypertension from day 8 to day 12. Both CAE groups showed similar structural changes in the pulmonary arteries. SLPI was well tolerated in control sheep and did not affect hemodynamics or structure. We conclude that serine proteases may contribute to the early initiation of chronic pulmonary hypertension but do not play a striking role in its eventual development.

scholarly journals Caveolar peroxynitrite formation impairs endothelial TRPV4 channels and elevates pulmonary arterial pressure in pulmonary hypertension

2021 ◽  
Vol 118 (17) ◽  
pp. e2023130118
Author(s):  
Zdravka Daneva ◽  
Corina Marziano ◽  
Matteo Ottolini ◽  
Yen-Lin Chen ◽  
Thomas M. Baker ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Endothelial Cell ◽  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Pulmonary Arteries ◽  
Lung Edema ◽  
Structural Protein ◽  
Caveolin 1 ◽  
Pulmonary Arterial ◽  
Trpv4 Channel

Recent studies have focused on the contribution of capillary endothelial TRPV4 channels to pulmonary pathologies, including lung edema and lung injury. However, in pulmonary hypertension (PH), small pulmonary arteries are the focus of the pathology, and endothelial TRPV4 channels in this crucial anatomy remain unexplored in PH. Here, we provide evidence that TRPV4 channels in endothelial cell caveolae maintain a low pulmonary arterial pressure under normal conditions. Moreover, the activity of caveolar TRPV4 channels is impaired in pulmonary arteries from mouse models of PH and PH patients. In PH, up-regulation of iNOS and NOX1 enzymes at endothelial cell caveolae results in the formation of the oxidant molecule peroxynitrite. Peroxynitrite, in turn, targets the structural protein caveolin-1 to reduce the activity of TRPV4 channels. These results suggest that endothelial caveolin-1–TRPV4 channel signaling lowers pulmonary arterial pressure, and impairment of endothelial caveolin-1–TRPV4 channel signaling contributes to elevated pulmonary arterial pressure in PH. Thus, inhibiting NOX1 or iNOS activity, or lowering endothelial peroxynitrite levels, may represent strategies for restoring vasodilation and pulmonary arterial pressure in PH.

scholarly journals Increased TMEM16A-encoded calcium-activated chloride channel activity is associated with pulmonary hypertension

2012 ◽  
Vol 303 (12) ◽  
pp. C1229-C1243 ◽  
Author(s):  
Abigail S. Forrest ◽  
Talia C. Joyce ◽  
Marissa L. Huebner ◽  
Ramon J. Ayon ◽  
Michael Wiwchar ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Electromechanical Coupling ◽  
Pulmonary Arteries ◽  
Doppler Imaging ◽  
Heart Weight ◽  
Channel Activity ◽  
Cl Channels ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle

Pulmonary artery smooth muscle cells (PASMCs) are more depolarized and display higher Ca2+ levels in pulmonary hypertension (PH). Whether the functional properties and expression of Ca2+-activated Cl− channels (ClCa), an important excitatory mechanism in PASMCs, are altered in PH is unknown. The potential role of ClCa channels in PH was investigated using the monocrotaline (MCT)-induced PH model in the rat. Three weeks postinjection with a single dose of MCT (50 mg/kg ip), the animals developed right ventricular hypertrophy (heart weight measurements) and changes in pulmonary arterial flow (pulse-waved Doppler imaging) that were consistent with increased pulmonary arterial pressure and PH. Whole cell patch experiments revealed an increase in niflumic acid (NFA)-sensitive Ca2+-activated Cl− current [ ICl(Ca)] density in PASMCs from large conduit and small intralobar pulmonary arteries of MCT-treated rats vs. aged-matched saline-injected controls. Quantitative RT-PCR and Western blot analysis revealed that the alterations in ICl(Ca) were accompanied by parallel changes in the expression of TMEM16A, a gene recently shown to encode for ClCa channels. The contraction to serotonin of conduit and intralobar pulmonary arteries from MCT-treated rats exhibited greater sensitivity to nifedipine (1 μM), an l-type Ca2+ channel blocker, and NFA (30 or 100 μM, with or without 10 μM indomethacin to inhibit cyclooxygenases) or T16AInh-A01 (10 μM), TMEM16A/ClCa channel inhibitors, than that of control animals. In conclusion, augmented ClCa/TMEM16A channel activity is a major contributor to the changes in electromechanical coupling of PA in this model of PH. TMEM16A-encoded channels may therefore represent a novel therapeutic target in this disease.

scholarly journals Pentaerythritol Tetranitrate In Vivo Treatment Improves Oxidative Stress and Vascular Dysfunction by Suppression of Endothelin-1 Signaling in Monocrotaline-Induced Pulmonary Hypertension

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Sebastian Steven ◽  
Matthias Oelze ◽  
Moritz Brandt ◽  
Elisabeth Ullmann ◽  
Swenja Kröller-Schön ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pulmonary Hypertension ◽  
Endothelial Dysfunction ◽  
Endothelial Function ◽  
Whole Blood ◽  
Pulmonary Arteries ◽  
Vascular Wall ◽  
Pentaerythritol Tetranitrate ◽  
Endothelin 1 ◽  
Pulmonary Arterial

Objective. Oxidative stress and endothelial dysfunction contribute to pulmonary arterial hypertension (PAH). The role of the nitrovasodilator pentaerythritol tetranitrate (PETN) on endothelial function and oxidative stress in PAH has not yet been defined.Methods and Results. PAH was induced by monocrotaline (MCT, i.v.) in Wistar rats. Low (30 mg/kg; MCT30), middle (40 mg/kg; MCT40), or high (60 mg/kg; MCT60) dose of MCT for 14, 28, and 42 d was used. MCT induced endothelial dysfunction, pulmonary vascular wall thickening, and fibrosis, as well as protein tyrosine nitration. Pulmonary arterial pressure and heart/body and lung/body weight ratio were increased in MCT40 rats (28 d) and reduced by oral PETN (10 mg/kg, 24 d) therapy. Oxidative stress in the vascular wall, in the heart, and in whole blood as well as vascular endothelin-1 signaling was increased in MCT40-treated rats and normalized by PETN therapy, likely by upregulation of heme oxygenase-1 (HO-1). PETN therapy improved endothelium-dependent relaxation in pulmonary arteries and inhibited endothelin-1-induced oxidative burst in whole blood and the expression of adhesion molecule (ICAM-1) in endothelial cells.Conclusion. MCT-induced PAH impairs endothelial function (aorta and pulmonary arteries) and increases oxidative stress whereas PETN markedly attenuates these adverse effects. Thus, PETN therapy improves pulmonary hypertension beyond its known cardiac preload reducing ability.

scholarly journals Oxidation of PKGIα mediates an endogenous adaptation to pulmonary hypertension

2019 ◽  
Vol 116 (26) ◽  
pp. 13016-13025 ◽  
Author(s):  
Olena Rudyk ◽  
Alice Rowan ◽  
Oleksandra Prysyazhna ◽  
Susanne Krasemann ◽  
Kristin Hartmann ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arteries ◽  
Adaptive Mechanism ◽  
Wild Type ◽  
Mesenchymal Transition ◽  
Nadph Oxidase 4 ◽  
Systemic Oxidative Stress ◽  
Superoxide Dismutase 3 ◽  
Pulmonary Arterial ◽  
Endothelial To Mesenchymal Transition

Chronic hypoxia causes pulmonary hypertension (PH), vascular remodeling, right ventricular (RV) hypertrophy, and cardiac failure. Protein kinase G Iα (PKGIα) is susceptible to oxidation, forming an interprotein disulfide homodimer associated with kinase targeting involved in vasodilation. Here we report increased disulfide PKGIα in pulmonary arteries from mice with hypoxic PH or lungs from patients with pulmonary arterial hypertension. This oxidation is likely caused by oxidants derived from NADPH oxidase-4, superoxide dismutase 3, and cystathionine γ-lyase, enzymes that were concomitantly increased in these samples. Indeed, products that may arise from these enzymes, including hydrogen peroxide, glutathione disulfide, and protein-bound persulfides, were increased in the plasma of hypoxic mice. Furthermore, low-molecular-weight hydropersulfides, which can serve as “superreductants” were attenuated in hypoxic tissues, consistent with systemic oxidative stress and the oxidation of PKGIα observed. Inhibiting cystathionine γ-lyase resulted in decreased hypoxia-induced disulfide PKGIα and more severe PH phenotype in wild-type mice, but not in Cys42Ser PKGIα knock-in (KI) mice that are resistant to oxidation. In addition, KI mice also developed potentiated PH during hypoxia alone. Thus, oxidation of PKGIα is an adaptive mechanism that limits PH, a concept further supported by polysulfide treatment abrogating hypoxia-induced RV hypertrophy in wild-type, but not in the KI, mice. Unbiased transcriptomic analysis of hypoxic lungs before structural remodeling identified up-regulation of endothelial-to-mesenchymal transition pathways in the KI compared with wild-type mice. Thus, disulfide PKGIα is an intrinsic adaptive mechanism that attenuates PH progression not only by promoting vasodilation but also by limiting maladaptive growth and fibrosis signaling.

scholarly journals The serotonin hypothesis in pulmonary hypertension revisited: targets for novel therapies (2017 Grover Conference Series)

2018 ◽  
Vol 8 (2) ◽  
pp. 204589401875912 ◽  
Author(s):  
Margaret (Mandy) R. MacLean
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arteries ◽  
Convincing Evidence ◽  
Current Status ◽  
Novel Therapies ◽  
Serotonin Synthesis ◽  
Pulmonary Arterial ◽  
Arterial Smooth Muscle Cells ◽  
Diet Pills ◽  
Sert Activity

Increased synthesis of serotonin and/or activity of serotonin in pulmonary arteries has been implicated in the pathobiology of pulmonary arterial hypertension (PAH). The incidence of PAH associated with diet pills such as aminorex, fenfluramine, and chlorphentermine initially led to the “serotonin hypothesis of pulmonary hypertension.” Over the last couple of decades there has been an accumulation of convincing evidence that targeting serotonin synthesis or signaling is a novel and promising approach to the development of novel therapies for PAH. Pulmonary endothelial serotonin synthesis via tryptophan hydroxlase 1 (TPH1) is increased in patients with PAH and serotonin can act in a paracrine fashion on underlying pulmonary arterial smooth muscle cells (PASMCs), In humans, serotonin can enter PASMCs via the serotonin transporter (SERT) or activate the 5-HT1B receptor; 5-HT1B activation and SERT activity cooperate to induce PASMC contraction and proliferation via activation of downstream proliferative and contractile signaling pathways. Here we will review the current status of the serotonin hypothesis and discuss potential and novel therapeutic targets.

The Influence of Pulmonary Hemodynamics on Right Ventricular Function in Pulmonary Hypertension

2013 ◽  
Author(s):  
Vitaly O. Kheyfets ◽  
Lourdes Rios ◽  
Triston Smith ◽  
Theodore Schroeder ◽  
Jeffrey Mueller ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Pulmonary Hypertension ◽  
Shear Stress ◽  
Right Ventricular ◽  
Pulmonary Arteries ◽  
Pulmonary Hemodynamics ◽  
Arterial Hemodynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Pulmonary Arterial ◽  
Rv Function

Pulmonary arterial hypertension (PAH) is a degenerative disease that can lead to substantial morphometric remodeling of the pulmonary arteries. Previous studies have revealed coupling relationships between right ventricular (RV) function and pulmonary arterial hemodynamics. The objective of this study was to utilize computational fluid dynamics (CFD) to estimate spatially averaged Wall Shear Stress (WSS) for patients with PH and explore correlations between hemodynamics metrics and RV function.

Effect of selective embolization of various sized pulmonary arteries in dogs

1963 ◽  
Vol 204 (4) ◽  
pp. 619-625 ◽  
Author(s):  
John W. Hyland ◽  
George T. Smith ◽  
Lockhart B. McGuire ◽  
Donald C. Harrison ◽  
Florence W. Haynes ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Internal Diameter ◽  
Polystyrene Spheres ◽  
Selective Embolization ◽  
Blood Clots ◽  
Pulmonary Arterial ◽  
The Right

Pulmonary embolism was produced in 30 closed-chest 8-kg dogs with polystyrene spheres, glass beads, or blood clots of precise graded size. The sizes matched selectively the internal diameter of pulmonary arteries from lobar branches (5–6 mm) down to atrial arteries (0.17 mm). Emboli were injected into the right atrium until the pressure in the pulmonary artery rose 5–10 mm Hg. The number of emboli of a given size required to produce this incipient pulmonary hypertension was compared with the number of vessels of that same size as determined from the literature as well as by postmortem injection with Schlesinger mass. The number of emboli bore a constant relation to the number of vessels of that same size. With each size, the majority of vessels had to be occluded before pulmonary hypertension appeared. This was true even in the absence of anesthesia. The results support the thesis that mechanical blockade rather than vasoconstriction is the mechanism by which pulmonary hypertension is produced by emboli occluding pulmonary arterial (as opposed to arteriolar) vessels.

scholarly journals Pulmonary vessel casting in a rat model of monocrotaline-mediated pulmonary hypertension

2020 ◽  
Vol 10 (3) ◽  
pp. 204589402092212
Author(s):  
Zhongkai Zhu ◽  
Yifan Wang ◽  
Amy Long ◽  
Tianyu Feng ◽  
Maria Ocampo ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Rat Model ◽  
Vascular System ◽  
Pulmonary Arteries ◽  
Pulmonary Vasculature ◽  
Control Group ◽  
Wall Thickening ◽  
Arterial Remodeling ◽  
Pulmonary Vessel ◽  
Pulmonary Arterial

Pulmonary hypertension is a chronic vascular disease characterized by pulmonary vasoconstriction and pulmonary arterial remodeling. Pulmonary arterial remodeling is mainly due to small pulmonary arterial wall thickening and lumen occlusion. Previous studies have described intravascular changes in lung sections using histopathology, but few were able to obtain a fine detailed image of the pulmonary vascular system. In this study, we used Microfil compounds to cast the pulmonary arteries in a rat model of monocrotaline-induced pulmonary hypertension. High-quality images that enabled quantification of distal pulmonary arterial branching based on the number of vessel bifurcations/junctions were demonstrated in this model. The branch and junction counts of distal pulmonary arteries significantly decreased in the monocrotaline group compared to the control group, and this effect was inversely proportional to the mean pulmonary artery pressure observed in each group. The patterns of pulmonary vasculature and the methods for pulmonary vessel casting are presented to provide a basis for future studies of pulmonary arterial remodeling due to pulmonary hypertension and other lung diseases that involve the remodeling of vasculature.

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