scholarly journals Hypoxia inhibits adenylyl cyclase catalytic activity in a porcine model of persistent pulmonary hypertension of the newborn

2018 ◽  
Vol 315 (6) ◽  
pp. L933-L944 ◽  
Author(s):  
A. S. Sikarwar ◽  
M. Hinton ◽  
K. T. Santhosh ◽  
P. Dhanaraj ◽  
M. Talabis ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Catalytic Activity ◽  
Adenylyl Cyclase ◽  
Specific Activity ◽  
Pulmonary Arteries ◽  
Persistent Pulmonary Hypertension ◽  
Receptor Agonists ◽  
Pulmonary Arterial ◽  
Fraction Of Inspired Oxygen

Persistent pulmonary hypertension of the newborn (PPHN) features hypoxemia, pulmonary vasoconstriction, and impaired cardiac inotropy. We previously reported low basal and stimulated cAMP in hypoxic pulmonary artery smooth muscle cells (PASMCs). We now examine pulmonary arterial adenylyl cyclase (AC) activity and regulation in hypoxic PPHN. PPHN was induced in newborn swine by normobaric hypoxia (fraction of inspired oxygen 0.10) for 72 h and compared with age-matched normoxic controls. We studied relaxation of pulmonary arterial (PA) rings to AC activator forskolin and cGMP activator sodium nitroprusside (SNP) by isometric myography, ATP content, phosphodiesterase activity, AC content, isoform expression, and catalytic activity in presence or absence of Gαs-coupled receptor agonists, forskolin, or transnitrosylating agents in human and neonatal porcine PASMCs and HEK293T stably expressing AC isoform 6, after 72 h hypoxia (10% O2) or normoxia (21% O2). Relaxation to forskolin and SNP were equally impaired in PPHN PA. AC-specific activity decreased in hypoxia. PASMC from PPHN swine had reduced AC activity despite exposure to normoxia in culture; transient hypoxia in vitro further decreased AC activity. Prostacyclin receptor ligand affinity decreased, but its association with Gαs increased in hypoxia. Total AC content was unchanged by hypoxia, but AC6 increased in hypoxic cells and PPHN pulmonary arteries. Impairment of AC6 activity in hypoxia was associated with nitrosylation. PPHN PA relaxation is impaired because of loss of AC activity. Hypoxic AC is inhibited because of S-nitrosylation; inhibition persists after removal from hypoxia. Downregulation of AC-mediated relaxation in hypoxic PA has implications for utility of Gαs-coupled receptor agonists in PPHN treatment.

scholarly journals Serotonin contributes to high pulmonary vascular tone in a sheep model of persistent pulmonary hypertension of the newborn

2013 ◽  
Vol 304 (12) ◽  
pp. L894-L901 ◽  
Author(s):  
Cassidy Delaney ◽  
Jason Gien ◽  
Gates Roe ◽  
Nicole Isenberg ◽  
Jenai Kailey ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Tryptophan Hydroxylase ◽  
Late Gestation ◽  
Persistent Pulmonary Hypertension ◽  
Sheep Model ◽  
Pulmonary Hemodynamics ◽  
Fetal Sheep ◽  
Pulmonary Arterial

Although past studies demonstrate that altered serotonin (5-HT) signaling is present in adults with idiopathic pulmonary arterial hypertension, whether serotonin contributes to the pathogenesis of persistent pulmonary hypertension of the newborn (PPHN) is unknown. We hypothesized that 5-HT contributes to increased pulmonary vascular resistance (PVR) in a sheep model of PPHN and that selective 5-HT reuptake inhibitor (SSRI) treatment increases PVR in this model. We studied the hemodynamic effects of 5-HT, ketanserin (5-HT2A receptor antagonist), and sertraline, an SSRI, on pulmonary hemodynamics of the late gestation fetal sheep with PPHN caused by prolonged constriction of the ductus arteriosis. Brief intrapulmonary infusions of 5-HT increased PVR from 1.0 ± 0.07 (baseline) to 1.4 ± 0.22 mmHg/ml per minute of treatment ( P < 0.05). Ketanserin decreased PVR from 1.1 ± 0.15 (baseline) to 0.82 ± 0.09 mmHg/ml per minute of treatment ( P < 0.05). Sertraline increased PVR from 1.1 ± 0.17 (baseline) to 1.4 ± 0.17 mmHg/ml per minute of treatment ( P = 0.01). In addition, we studied 5-HT production and activity in vitro in experimental PPHN. Compared with controls, pulmonary artery endothelial cells from fetal sheep with PPHN exhibited increased expression of tryptophan hydroxylase 1 and 5-HT production by twofold and 56%, respectively. Compared with controls, 5-HT2A R expression was increased in lung homogenates and pulmonary artery smooth muscle cell lysates by 35% and 32%, respectively. We concluded that increased 5-HT contributes to high PVR in experimental PPHN through activation of the 5-HT2A receptor and that SSRI infusion further increases PVR in this model.

scholarly journals Hydrogen Sulfide Metabolism and Pulmonary Hypertension

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1477
Author(s):  
Lukas Roubenne ◽  
Roger Marthan ◽  
Bruno Le Le Grand ◽  
Christelle Guibert
Keyword(s):  
Pulmonary Hypertension ◽  
Hydrogen Sulfide ◽  
Pulmonary Circulation ◽  
Pulmonary Arteries ◽  
K Channel ◽  
Protective Effects ◽  
Pulmonary Arterial ◽  
Regulatory Functions

Pulmonary hypertension (PH) is a severe and multifactorial disease characterized by a progressive elevation of pulmonary arterial resistance and pressure due to remodeling, inflammation, oxidative stress, and vasoreactive alterations of pulmonary arteries (PAs). Currently, the etiology of these pathological features is not clearly understood and, therefore, no curative treatment is available. Since the 1990s, hydrogen sulfide (H2S) has been described as the third gasotransmitter with plethoric regulatory functions in cardiovascular tissues, especially in pulmonary circulation. Alteration in H2S biogenesis has been associated with the hallmarks of PH. H2S is also involved in pulmonary vascular cell homeostasis via the regulation of hypoxia response and mitochondrial bioenergetics, which are critical phenomena affected during the development of PH. In addition, H2S modulates ATP-sensitive K+ channel (KATP) activity, and is associated with PA relaxation. In vitro or in vivo H2S supplementation exerts antioxidative and anti-inflammatory properties, and reduces PA remodeling. Altogether, current findings suggest that H2S promotes protective effects against PH, and could be a relevant target for a new therapeutic strategy, using attractive H2S-releasing molecules. Thus, the present review discusses the involvement and dysregulation of H2S metabolism in pulmonary circulation pathophysiology.

scholarly journals Increased hydrogen peroxide downregulates soluble guanylate cyclase in the lungs of lambs with persistent pulmonary hypertension of the newborn

2005 ◽  
Vol 289 (4) ◽  
pp. L660-L666 ◽  
Author(s):  
Stephen Wedgwood ◽  
Robin H. Steinhorn ◽  
Melisa Bunderson ◽  
Jason Wilham ◽  
Satyan Lakshminrusimha ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pulmonary Hypertension ◽  
Guanylate Cyclase ◽  
Soluble Guanylate Cyclase ◽  
Pulmonary Arteries ◽  
Persistent Pulmonary Hypertension ◽  
Ovine Model ◽  
Ros Scavenger ◽  
Pulmonary Arterial ◽  
Initial Objective

Similar to infants born with persistent pulmonary hypertension of the newborn (PPHN), there is an increase in circulating endothelin-1 (ET-1) and decreased cGMP-mediated vasodilation in an ovine model of PPHN. These abnormalities lead to vasoconstriction and vascular remodeling. Our previous studies have demonstrated that reactive oxygen species (ROS) levels are increased in pulmonary arterial smooth muscle cells (PASMC) exposed to ET-1. Thus the initial objective of this study was to determine whether the development of pulmonary hypertension in utero is associated with elevated production of the ROS hydrogen peroxide (H2O2) and if this is associated with alterations in antioxidant capacity. Second we wished to determine whether chronic exposure of PASMC isolated from fetal lambs to H2O2 would mimic the decrease in soluble guanylate cyclase expression observed in the ovine model of PPHN. Our results indicate that H2O2 levels are significantly elevated in pulmonary arteries isolated from 136-day-old fetal PPHN lambs ( P 0.05). In addition, we determined that catalase and glutathione peroxidase expression and activities remain unchanged. Also, we found that the overnight exposure of fetal PASMC to a H2O2-generating system resulted in significant decreases in soluble guanylate cyclase expression and nitric oxide (NO)-dependent cGMP generation ( P 0.05). Finally, we demonstrated that the addition of the ROS scavenger catalase to isolated pulmonary arteries normalized the vasodilator responses to exogenous NO. As these scavengers had no effect on the vasodilator responses in pulmonary arteries isolated from age-matched control lambs this enhancement appears to be unique to PPHN. Overall our data suggest a role for H2O2 in the abnormal vasodilation associated with the pulmonary arteries of PPHN lambs.

A role for actin polymerization in persistent pulmonary hypertension of the newborn

2015 ◽  
Vol 93 (3) ◽  
pp. 185-194 ◽  
Author(s):  
Jena Fediuk ◽  
Shyamala Dakshinamurti
Keyword(s):  
Pulmonary Hypertension ◽  
Actin Polymerization ◽  
Pulmonary Arteries ◽  
Persistent Pulmonary Hypertension ◽  
Vascular Relaxation ◽  
Cortical Actin ◽  
Actin Isoform ◽  
Pulmonary Arterial

Persistent pulmonary hypertension of the newborn (PPHN) is defined as the failure of normal pulmonary vascular relaxation at birth. Hypoxia is known to impede postnatal disassembly of the actin cytoskeleton in pulmonary arterial myocytes, resulting in elevation of smooth muscle α-actin and γ-actin content in elastic and resistance pulmonary arteries in PPHN compared with age-matched controls. This review examines the original histological characterization of PPHN with attention to cytoskeletal structural remodeling and actin isoform abundance, reviews the existing evidence for understanding the biophysical and biochemical forces at play during neonatal circulatory transition, and specifically addresses the role of the cortical actin architecture, primarily identified as γ-actin, in the transduction of mechanical force in the hypoxic PPHN pulmonary circuit.

Systemic arteriovenous fistula leads to pulmonary artery remodeling and abnormal vasoreactivity in the fetal lamb

2003 ◽  
Vol 285 (3) ◽  
pp. L701-L709 ◽  
Author(s):  
Jean-Marie Jouannic ◽  
Régine Roussin ◽  
Alison A. Hislop ◽  
Sophie Lanone ◽  
Jelena Martinovic ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Arteriovenous Fistula ◽  
Relative Number ◽  
Persistent Pulmonary Hypertension ◽  
Pulmonary Vasculature ◽  
Organ Bath ◽  
Fetal Lamb ◽  
Pulmonary Arterial

Several cases of systemic arteriovenous fistula diagnosed in the human fetus have been associated with the postnatal development of persistent pulmonary hypertension. The aim of this study was to determine the effects of a prenatally created systemic arteriovenous fistula on the structure and reactivity of the pulmonary circulation in the fetal lamb. A fistula between the jugular vein and carotid artery was created in fetal lambs at 119-124 days of gestation. At delivery (134-139 days), left pulmonary artery (LPA) pressure was increased in the fistula group ( n = 12) compared with controls ( n = 11, P < 0.01). The pulmonary vascular resistance was significantly higher in the fistula group ( P < 0.05), whereas mean LPA blood flow was not statistically different between the two groups. Morphometric analysis of the pulmonary vascular bed revealed an increase in the number of peripheral muscular arteries, together with an increase in pulmonary arterial medial thickness in the fistula group. There was no difference in the relative number or size of intraacinar arteries. In vitro organ bath studies on pulmonary arterial rings showed impaired endothelium-dependent relaxation in the fistula group compared with controls. However, endothelial nitric oxide synthase protein expression was similar in both groups, whereas endothelium-independent relaxation to sodium nitroprusside was greater in the fistula group compared with controls. A systemic arteriovenous fistula leads to both structural and functional alteration of the pulmonary vasculature, which might lead to the development of persistent pulmonary hypertension after birth.

Three-week neonatal hypoxia reduces blood CGRP and causes persistent pulmonary hypertension in rats

2000 ◽  
Vol 279 (4) ◽  
pp. H1571-H1578 ◽  
Author(s):  
I. M. Keith ◽  
S. Tjen-A-Looi ◽  
H. Kraiczi ◽  
R. Ekman
Keyword(s):  
Pulmonary Hypertension ◽  
Ventricular Hypertrophy ◽  
Pulmonary Arterial Pressure ◽  
Pulmonary Arteries ◽  
Left Ventricular ◽  
Persistent Pulmonary Hypertension ◽  
Perinatal Exposure ◽  
Calcitonin Gene ◽  
Potent Vasodilator ◽  
Pulmonary Arterial

To increase understanding of persistent pulmonary hypertension, we examined chronic pulmonary effects of hypoxia at birth and their relationships with immunoreactive levels of the potent vasodilator, calcitonin gene-related peptide (CGRP). Rats were born in 10% hypobaric hypoxia, where they remained for 1–2 days, or in 15% hypoxia, where they remained for 21 days. All were then reared in normoxia for 3 mo followed by reexposure to 10% hypoxia for 7 days (H→H) or continued normoxia (H→N); age-matched normoxic rats were hypoxic for the last 7 days (N→H) or normoxic throughout (N→N). Results are as follows. Pulmonary arterial pressure (PPA) in 10% H→N rats was normal at the end of the experiment (13 wk), but in rats reexposed to hypoxia (H→H), pressure rose to 19% above N→H controls. In 15% H→N rats, PPA remained high, similar to that of N→H rats, and increased further by 40% on reexposure (H→H). Medial thickness of small pulmonary arteries in 10% H→H rats also increased by 40% over N→H controls and was equally high in 15% H→N and H→H rats. In N→H rats from both experiments, right ventricular hypertrophy index (RVH) was increased after hypoxia at 15–16 wk. Also, in the 15% study, RVH remained elevated in H→N rats and increased in H→H rats by 19% above N→H controls. Blood CGRP was reduced by neonate and adult hypoxia, and hypoxic reexposure (H→H) further lowered blood CGRP in the 15% but not 10% study. Declining left ventricular blood CGRP correlated highly with logarithmically increasing PPA in the 15% study ( r = −0.81, P = 0.000). In conclusion, 1) short perinatal exposure to 10% O2 exacerbated pulmonary hypertension with hypoxia later in life, 2) 15% O2 at birth and for 21 days caused persistent pulmonary hypertension and exacerbation with reexposure, and 3) PPA correlated highly with declining blood CGRP levels in the 15% study.

scholarly journals Endothelial cell senescence exacerbates pulmonary hypertension through Notch-mediated juxtacrine signaling

2021 ◽  
Author(s):  
Risa Ramadhiani ◽  
Koji Ikeda ◽  
Kazuya Miyagawa ◽  
Gusty Rizky Teguh Ryanto ◽  
Naoki Tamada ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Notch Signaling ◽  
Pulmonary Arteries ◽  
Hypoxia Exposure ◽  
Pulmonary Arterial ◽  
Arterial Smooth Muscle Cells ◽  
And Migration ◽  
Notch Ligands

AbstractPulmonary arterial hypertension (PAH) is a fatal disease characterized by pathological pulmonary artery remodeling. Endothelial cells (EC) injury including DNA damage is critically involved in the vascular remodeling in PAH, and persistent injury leads to cellular senescence in ECs. Here, we show that EC senescence exacerbates pulmonary hypertension through Notch-mediated juxtacrine signaling. EC-specific progeroid mice that we recently generated showed exacerbated pulmonary hypertension after chronic hypoxia exposure, accompanied by the enhanced pulmonary arterial smooth muscle cells (PASMCs) proliferation in the distal pulmonary arteries. Mechanistically, we identified that senescent ECs highly expressed Notch ligands, and thus activated Notch signaling in PASMCs, leading to enhanced PASMCs proliferation and migration capacities. Consistently, pharmacological inhibition of Notch signaling attenuated the effects of senescent ECs on SMCs functions in vitro, and on the pulmonary hypertension in EC-specific progeroid mice in vivo. These data establish EC senescence as a crucial disease-modifying facor in PAH.

scholarly journals Oxygen-Sensitivity and Pulmonary Selectivity of Vasodilators as Potential Drugs for Pulmonary Hypertension

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 155
Author(s):  
Daniel Morales-Cano ◽  
Bianca Barreira ◽  
Beatriz De Olaiz Navarro ◽  
María Callejo ◽  
Gema Mondejar-Parreño ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Gas Exchange ◽  
Pulmonary Circulation ◽  
Pulmonary Arteries ◽  
Blood Perfusion ◽  
Mesenteric Arteries ◽  
Oxygen Sensitivity ◽  
Low Oxygen ◽  
Oxygen Selectivity

Current approved therapies for pulmonary hypertension (PH) aim to restore the balance between endothelial mediators in the pulmonary circulation. These drugs may exert vasodilator effects on poorly oxygenated vessels. This may lead to the derivation of blood perfusion towards low ventilated alveoli, i.e., producing ventilation-perfusion mismatch, with detrimental effects on gas exchange. The aim of this study is to analyze the oxygen-sensitivity in vitro of 25 drugs currently used or potentially useful for PH. Additionally, the study analyses the effectiveness of these vasodilators in the pulmonary vs. the systemic vessels. Vasodilator responses were recorded in pulmonary arteries (PA) and mesenteric arteries (MA) from rats and in human PA in a wire myograph under different oxygen concentrations. None of the studied drugs showed oxygen selectivity, being equally or more effective as vasodilators under conditions of low oxygen as compared to high oxygen levels. The drugs studied showed low pulmonary selectivity, being equally or more effective as vasodilators in systemic than in PA. A similar behavior was observed for the members within each drug family. In conclusion, none of the drugs showed optimal vasodilator profile, which may limit their therapeutic efficacy in PH.

Newborn rat response to single vs. combined cGMP-dependent pulmonary vasodilators

2014 ◽  
Vol 306 (2) ◽  
pp. L207-L215 ◽  
Author(s):  
Masahiro Enomoto ◽  
Amish Jain ◽  
Jingyi Pan ◽  
Yulia Shifrin ◽  
Todd Van Vliet ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Synergistic Effect ◽  
Soluble Guanylate Cyclase ◽  
Pulmonary Arteries ◽  
Small Heat Shock Protein ◽  
No Donor ◽  
Clinical Exposure ◽  
Pulmonary Vasodilators ◽  
Pulmonary Vasodilator

Inhaled nitric oxide (NO) and other cGMP- or cAMP-dependent pulmonary vasodilators are often used in combination for the treatment of the persistent pulmonary hypertension of the newborn syndrome. There is in vitro evidence to indicate that NO downregulate the pulmonary vascular response to cGMP-dependent agonists raising concern as to whether a synergistic effect is observed when employing a combined strategy in newborns. Hypothesizing that a synergistic effect is absent, we evaluated newborn and juvenile rat pulmonary arteries to determine the individual and combined vasodilatory effect of cGMP- and cAMP-dependent agonists. In precontracted near-resistance pulmonary arteries, the addition of sildenafil reduced vasorelaxation response to NO donor S-nitroso- N-acetyl penicillamine (SNAP). A similar decrease in SNAP-induced vasodilation was observed in arteries pretreated with BAY 41–2272 (10−9 M), a soluble guanylate cyclase stimulator cGMP, and its downstream protein kinase activator. cGMP also reduced the vasorelaxant response to the cAMP-dependent forskolin. Inhibition of endogenous vascular NO generation enhanced SNAP-induced relaxation. The present data suggest that the mechanism involved in the cGMP desensitization to other relaxant agonists involves downregulation of the small heat shock protein HSP20 and is evident in rat pulmonary and systemic vascular smooth muscle cells. In newborn rats with chronic hypoxia-induced pulmonary hypertension, the combination of sildenafil and inhaled NO resulted in a lesser reduction in pulmonary vascular resistance compared with their individual effect. These data suggest that clinical exposure to one cGMP-dependent pulmonary vasodilator may affect the response to other cGMP- or cAMP-mediated agonists.

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.

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