The endothelin system in pulmonary hypertension

2003 ◽  
Vol 81 (6) ◽  
pp. 542-554 ◽  
Author(s):  
René P Michel ◽  
David Langleben ◽  
Jocelyn Dupuis
Keyword(s):  
Clinical Trials ◽  
Pulmonary Hypertension ◽  
Pulmonary Circulation ◽  
Tissue Expression ◽  
Vascular Endothelial ◽  
Receptor Antagonists ◽  
New Class ◽  
Endothelin System ◽  
Pulmonary Arterial ◽  
Medial Hypertrophy

Pulmonary hypertension (PH) may result from numerous clinical entities affecting the pulmonary circulation primarily or secondarily. It is recognized that vascular endothelial dysfunction contributes to the development and perpetuation of PH by creating an imbalance between vasodilating and antiproliferative forces and between vasoconstric tive and proliferative forces. In that context, endothelin-1 (ET-1) overproduction was rapidly targeted as a plausible contributor to the pathogenesis of PH. The lung is recognized as the major site for ET production and clearance. In all animal models of PH studied, circulating plasma ET-1 levels are elevated, accompanied by an increase in lung tissue expression of the peptide. The use of selective ETA and dual ETA–ETB receptor antagonists in these models both in prevention and in therapeutic studies have confirmed the contribution of ET-1 to the rise in pulmonary vascular tone, pulmonary medial hypertrophy, and right ventricular hypertrophy. This is found consistently in models affecting the pulmonary circulation primarily or producing PH secondarily. Recent clinical trials in patients with pulmonary arterial hypertension have confirmed the therapeutic effectiveness of ET-receptor antagonists in humans. We offer a systematic review of the pathogenic role of the ET system in the development of PH as well as the rationale behind the preclinical and ongoing clinical trials with this new class of agents.Key words: pulmonary circulation, pulmonary pathology, receptor, preclinical studies, clinical studies, antagonist.

scholarly journals Endothelin Receptor Antagonism: A New Era in the Treatment of Pulmonary Arterial Hypertension

2002 ◽  
Vol 1 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Richard N. Channick ◽  
Lewis J. Rubin
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Endothelin Receptor Antagonists ◽  
Endothelin Receptor ◽  
Receptor Antagonists ◽  
Double Blind ◽  
Beneficial Effects ◽  
Endothelin System ◽  
Pulmonary Arterial

Abstract The endothelin system has been extensively studied over the last several years. It is clear that endothelin-1 (ET-1) is a key mediator in pulmonary vascular biology and physiology. Abnormal increases in ET-1 production and decreased pulmonary clearance appear to play a major pathogenetic and perpetuating role in the pulmonary hypertensive process, through their vasconstrictive, smooth muscle cell proliferative and profibrotic effects. The degree of overexpression of ET-1 may correlate with the severity of pulmonary hypertension (PH). Advances in understanding the role of ET-1 in pulmonary hypertension have driven the development of endothelin receptor antagonists. One such agent, bosentan (Tracleer), is FDA approved for pulmonary arterial hypertension. Bosentan was approved following two randomized, placebo-controlled, double-blind studies that both showed marked improvement in exercise capacity after treatment with bosentan. The beneficial effects of bosentan appear to be sustained in most patients followed for as long as 22 months. Other uses for endothelin receptor antagonists are being examined, such as in combination with epoprostenol (Flolan) or in pediatric PH patients.

scholarly journals Pharmacological Potential of Endothelin Receptors Agonists and Antagonists

2005 ◽  
Vol 48 (2) ◽  
pp. 67-73
Author(s):  
Jiří Patočka ◽  
Vladimír Měrka ◽  
Vratislav Hrdina ◽  
Radomír Hrdina
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Clinical Trials ◽  
Pulmonary Hypertension ◽  
Endothelin Receptors ◽  
Great Promise ◽  
Receptor Antagonists ◽  
Endothelin 1 ◽  
Endothelin System ◽  
Pharmacological Potential

Endothelins are potent predominantly vasoconstricting agents that act as local autocrine and paracrine mediators. Endothelin-1 is the most potent and sustained vasoconstrictor and pressor substance yet identified. Abnormalities of the endothelin system occur in a range of diseases associated with vasoconstriction, vasospasm, and vascular hypertrophy. ET receptor antagonists were until recently regarded as drugs of great promise in patients with congestive heart failure, pulmonary hypertension and others. The aim of this article is a survey of compounds that affect the endothelin receptors and clinical trials with these agents.

scholarly journals Decreased time constant of the pulmonary circulation in chronic thromboembolic pulmonary hypertension

2013 ◽  
Vol 305 (2) ◽  
pp. H259-H264 ◽  
Author(s):  
Robert V. MacKenzie Ross ◽  
Mark R. Toshner ◽  
Elaine Soon ◽  
Robert Naeije ◽  
Joanna Pepke-Zaba
Keyword(s):  
Pulmonary Hypertension ◽  
Time Constant ◽  
Pulmonary Circulation ◽  
Wave Reflection ◽  
Arterial Compliance ◽  
Chronic Thromboembolic Pulmonary Hypertension ◽  
Left Heart Failure ◽  
Thromboembolic Pulmonary Hypertension ◽  
Pulmonary Arterial ◽  
Rc Time Constant

This study analyzed the relationship between pulmonary vascular resistance (PVR) and pulmonary arterial compliance ( Ca) in patients with idiopathic pulmonary arterial hypertension (IPAH) and proximal chronic thromboembolic pulmonary hypertension (CTEPH). It has recently been shown that the time constant of the pulmonary circulation (RC time constant), or PVR × Ca, remains unaltered in various forms and severities of pulmonary hypertension, with the exception of left heart failure. We reasoned that increased wave reflection in proximal CTEPH would be another cause of the decreased RC time constant. We conducted a retrospective analysis of invasive pulmonary hemodynamic measurements in IPAH ( n = 78), proximal CTEPH ( n = 91) before (pre) and after (post) pulmonary endarterectomy (PEA), and distal CTEPH ( n = 53). Proximal CTEPH was defined by a postoperative mean pulmonary artery pressure (PAP) of ≤25 mmHg. Outcome measures were the RC time constant, PVR, Ca, and relationship between systolic and mean PAPs. The RC time constant for pre-PEA CTEPH was 0.49 ± 0.11 s compared with post-PEA-CTEPH (0.37 ± 0.11 s, P < 0.0001), IPAH (0.63 ± 0.14 s, P < 0.001), and distal CTEPH (0.55 ± 0.12 s, P < 0.05). A shorter RC time constant was associated with a disproportionate decrease in systolic PAP with respect to mean PAP. We concluded that the pulmonary RC time constant is decreased in proximal CTEPH compared with IPAH, pre- and post-PEA, which may be explained by increased wave reflection but also, importantly, by persistent structural changes after the removal of proximal obstructions. A reduced RC time constant in CTEPH is in accord with a wider pulse pressure and hence greater right ventricular work for a given mean PAP.

scholarly journals Barriers and Solutions to Developing Future Therapies for Pulmonary Hypertension

2018 ◽  
Vol 17 (4) ◽  
pp. 159-165
Author(s):  
Brian Graham ◽  
Peter Fernandes ◽  
Sue Gu
Keyword(s):  
Clinical Trials ◽  
Pulmonary Hypertension ◽  
Phase 1 ◽  
Unmet Need ◽  
Orphan Drugs ◽  
World Health ◽  
Vasodilator Therapy ◽  
Scarce Resources ◽  
Pulmonary Arterial ◽  
Health Organization

Pulmonary hypertension (PH) and its subset, pulmonary arterial hypertension (PAH), are rare diseases with a significant unmet need. Between the 1980s and 2010s, the 5-year survival rate for PAH after diagnosis improved from 34% to 65%,12 but remains unacceptably low. Since the introduction of vasodilator therapy, 34 important advances have been made in the understanding of the disease pathophysiology and development of targeted therapies. There are now 14 US Food and Drug Administration (FDA)-approved therapies that target 3 distinct pathways that contribute to PAH, and additional therapeutic targets are currently under investigation in phase 1, 2, and 3 clinical trials.5 However, there have been major challenges in PH medication development to date, including: 1) only one medication approved for pediatric PAH; 2) focusing on vasodilator therapy rather than targeting the underlying pathogenesis of the disease; 3) no medications approved for PH World Health Organization (WHO) Groups 2, 3, and 5; and 4) several recent high-profile clinical failures after promising preclinical studies.The focus and goal of the PH research community should be directed at identifying new options and solutions for patients. The field must ensure that the approaches used for clinical trials to develop orphan drugs maximize the scarce resources available for recruiting subjects, and are directed toward making safe and effective therapies available in a timely manner. Therefore, there is a critical need to coordinate and harmonize innovative approaches within the field, including strengthening translational research to deliver promising candidates and optimize the designs, endpoints, and biomarkers to conduct safe and efficient clinical trials.

scholarly journals 55th Bowditch Lecture: Effects of chronic hypoxia on the pulmonary circulation: Role of HIF-1

2012 ◽  
Vol 113 (9) ◽  
pp. 1343-1352 ◽  
Author(s):  
Larissa A. Shimoda
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Circulation ◽  
Vascular Remodeling ◽  
Chronic Hypoxia ◽  
Critical Role ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Inducible Factor 1 ◽  
Pulmonary Arterial ◽  
Expression And Activity

When exposed to chronic hypoxia (CH), the pulmonary circulation responds with enhanced contraction and vascular remodeling, resulting in elevated pulmonary arterial pressures. Our work has identified CH-induced alterations in the expression and activity of several ion channels and transporters in pulmonary vascular smooth muscle that contribute to the development of hypoxic pulmonary hypertension and uncovered a critical role for the transcription factor hypoxia-inducible factor-1 (HIF-1) in mediating these responses. Current work is focused on the regulation of HIF in the chronically hypoxic lung and evaluation of the potential for pharmacological inhibitors of HIF to prevent, reverse, or slow the progression of pulmonary hypertension.

scholarly journals Modulation of miRNAs in Pulmonary Hypertension

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Sudhiranjan Gupta ◽  
Li Li
Keyword(s):  
Pulmonary Hypertension ◽  
Vascular Diseases ◽  
Treatment Modalities ◽  
Small Noncoding Rnas ◽  
New Class ◽  
Cell Remodeling ◽  
Arterial Endothelial Cell ◽  
Current Therapies ◽  
Pulmonary Arterial ◽  
New Treatment

MicroRNAs (miRNAs) have emerged as a new class of posttranscriptional regulators of many cardiac and vascular diseases. They are a class of small, noncoding RNAs that contributes crucial roles typically through binding of the 3′-untranslated region of mRNA. A single miRNA may influence several signaling pathways associated with cardiac remodeling by targeting multiple genes. Pulmonary hypertension (PH) is a rare disorder characterized by progressive obliteration of pulmonary (micro) vasculature that results in elevated vascular resistance, leading to right ventricular hypertrophy (RVH) and RV failure. The pathology of PH involves vascular cell remodeling including pulmonary arterial endothelial cell (PAEC) dysfunction and pulmonary arterial smooth muscle cell (PASMC) proliferation. There is no cure for this disease. Thus, novel intervention pathways that govern PH induced RVH may result in new treatment modalities. Current therapies are limited to reverse the vascular remodeling. Recent studies have demonstrated the roles of various miRNAs in the pathogenesis of PH and pulmonary disorders. This review provides an overview of recent discoveries on the role of miRNAs in the pathogenesis of PH and discusses the potential for miRNAs as therapeutic targets and biomarkers of PH at clinical setting.

scholarly journals Purinergic dysregulation in pulmonary hypertension

2016 ◽  
Vol 311 (1) ◽  
pp. H286-H298 ◽  
Author(s):  
Scott H. Visovatti ◽  
Matthew C. Hyman ◽  
Sascha N. Goonewardena ◽  
Anuli C. Anyanwu ◽  
Yogendra Kanthi ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Potential Role ◽  
Purinergic Signaling ◽  
Continuous Administration ◽  
P2x1 Receptor ◽  
Pulmonary Endothelium ◽  
Pulmonary Arterial ◽  
Medial Hypertrophy

Despite the fact that nucleotides and adenosine help regulate vascular tone through purinergic signaling pathways, little is known regarding their contributions to the pathobiology of pulmonary arterial hypertension, a condition characterized by elevated pulmonary vascular resistance and remodeling. Even less is known about the potential role that alterations in CD39 (ENTPD1), the ectonucleotidase responsible for the conversion of the nucleotides ATP and ADP to AMP, may play in pulmonary arterial hypertension. In this study we identified decreased CD39 expression on the pulmonary endothelium of patients with idiopathic pulmonary arterial hypertension. We next determined the effects of CD39 gene deletion in mice exposed to normoxia or normobaric hypoxia (10% oxygen). Compared with controls, hypoxic CD39−/− mice were found to have a markedly elevated ATP-to-adenosine ratio, higher pulmonary arterial pressures, more right ventricular hypertrophy, more arterial medial hypertrophy, and a pro-thrombotic phenotype. In addition, hypoxic CD39−/− mice exhibited a marked increase in lung P2X1 receptors. Systemic reconstitution of ATPase and ADPase enzymatic activities through continuous administration of apyrase decreased pulmonary arterial pressures in hypoxic CD39−/− mice to levels found in hypoxic CD39+/+ controls. Treatment with NF279, a potent and selective P2X1 receptor antagonist, lowered pulmonary arterial pressures even further. Our study is the first to implicate decreased CD39 and resultant alterations in circulating purinergic signaling ligands and cognate receptors in the pathobiology of pulmonary arterial hypertension. Reconstitution and receptor blocking experiments suggest that phosphohydrolysis of purinergic nucleotide tri- and diphosphates, or blocking of the P2X1 receptor could serve as treatment for pulmonary arterial hypertension. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/purinergic-dysregulation-in-pulmonary-hypertension/ .

Proximal pulmonary arterial obstruction decreases the time constant of the pulmonary circulation and increases right ventricular afterload

2013 ◽  
Vol 114 (11) ◽  
pp. 1586-1592 ◽  
Author(s):  
Alberto Pagnamenta ◽  
Rebecca Vanderpool ◽  
Serge Brimioulle ◽  
Robert Naeije
Keyword(s):  
Pulmonary Hypertension ◽  
Right Ventricular ◽  
Time Constant ◽  
Pulse Pressure ◽  
Pulmonary Circulation ◽  
Characteristic Impedance ◽  
Ventricular Afterload ◽  
Hydraulic Load ◽  
Distal Obstruction ◽  
Pulmonary Arterial

The time constant of the pulmonary circulation, or product of pulmonary vascular resistance (PVR) and compliance (Ca), called the RC-time, has been reported to remain constant over a wide range of pressures, etiologies of pulmonary hypertension, and treatments. We wondered if increased wave reflection on proximal pulmonary vascular obstruction, like in operable chronic thromboembolic pulmonary hypertension, might also decrease the RC-time and thereby increase pulse pressure and right ventricular afterload. Pulmonary hypertension of variable severity was induced either by proximal obstruction (pulmonary arterial ensnarement) or distal obstruction (microembolism) eight anesthetized dogs. Pulmonary arterial pressures (Ppa) were measured with high-fidelity micromanometer-tipped catheters, and pulmonary flow with transonic technology. Pulmonary ensnarement increased mean Ppa, PVR, and characteristic impedance, decreased Ca and the RC-time (from 0.46 ± 0.07 to 0.30 ± 0.03 s), and increased the oscillatory component of hydraulic load (Wosc/Wtot) from 25 ± 2 to 29 ± 2%. Pulmonary microembolism increased mean Ppa and PVR, with no significant change in Ca and characteristic impedance, increased RC-time from 0.53 ± 0.09 to 0.74 ± 0.05 s, and decreased Wosc/Wtot from 26 ± 2 to 13 ± 2%. Pulse pressure increased more after pulmonary ensnarement than after microembolism. Concomitant measurements with fluid-filled catheters showed the same functional differences between the two types of pulmonary hypertension, with, however, an underestimation of Wosc. We conclude that pulmonary hypertension caused by proximal vs. distal obstruction is associated with a decreased RC-time and increased pulsatile component of right ventricular hydraulic load.

scholarly journals Pulmonary hypertension: reasonable selection of specific therapy

2018 ◽  
Vol 15 (1) ◽  
pp. 45-50
Author(s):  
N A Karoli ◽  
S I Sazhnova ◽  
A P Rebrov
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Structural Changes ◽  
Pulmonary Arteries ◽  
Endothelin Receptor Antagonists ◽  
Endothelin Receptor ◽  
Receptor Antagonists ◽  
Pulmonary Vasodilator ◽  
Pulmonary Arterial

Pulmonary hypertension is characterized with persistent increase in pulmonary vascular resistance leading to progressive worsening of right ventricular failure and death. The basis for pulmonary arterial hypertension is structural changes in pulmonary arteries and arterioles caused by endothelial dysfunction. Endothelin-1 is the main pathogenic trigger of pulmonary hypertension and potential target for therapeutic exposure. The efficacy of endothelin receptor antagonists is proved in various preclinical and clinical studies. In patients with pulmonary arterial hypertension, the efficacy of dual and selective endothelin receptor antagonists is comparable despite the varied activity against various receptors. Bosentan is the most widely used pulmonary vasodilator which improves exercise tolerance and decelerates disease progression.

scholarly journals Novel composite clinical endpoints and risk scores used in clinical trials in pulmonary arterial hypertension

2020 ◽  
Vol 10 (4) ◽  
pp. 204589402096296 ◽  
Author(s):  
Olivier Sitbon ◽  
Sylvia Nikkho ◽  
Raymond Benza ◽  
Chunqin (CQ) Deng ◽  
Harrison W. Farber ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Pulmonary Hypertension ◽  
Risk Scores ◽  
Phase 2 ◽  
Innovative Drug ◽  
Future Design ◽  
Clinical Endpoints ◽  
Open Debate ◽  
Pulmonary Arterial ◽  
Composite Endpoints

This manuscript on endpoints incorporates the broad experience of members of Pulmonary Vascular Research Institute’s Innovative Drug Development Initiative as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. It reviews our current understanding of endpoints used in phase 2 and 3 trials for pulmonary hypertension and discusses in detail the value of newer approaches. These include the roles of composite endpoints and how these can be developed and validated. The newer concept of risk analysis is also discussed, including how such risk scores might be utilised as endpoints in clinical trials.

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