endothelin-1 and Familial-Primary-Pulmonary-Hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease with high morbidity and mortality. Deleterious remodeling in the pulmonary arterial system leads to irreversible arterial constriction and elevated pulmonary arterial pressures, right heart failure, and eventually death. The difficulty in treating PAH stems in part from the complex nature of disease pathogenesis, with several signaling compounds known to be involved (e.g., endothelin-1, prostacyclins) which are indeed targets of PAH therapy. Over the last decade, potassium channelopathies were established as novel causes of PAH. More specifically, loss-of-function mutations in the

Topics: Channelopathies; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; KATP Channels; Nerve Tissue Proteins; Potassium; Potassium Channels, Tandem Pore Domain; Potassium Channels, Voltage-Gated; Prostaglandins I; Pulmonary Arterial Hypertension

Pulmonary hypertension is a complex, progressive condition arising from a variety of genetic and pathogenic causes. Patients present with a spectrum of histologic and pathophysiological features, likely reflecting the diversity in underlying pathogenesis. It is widely recognized that structural alterations in the vascular wall contribute to all forms of pulmonary hypertension. Features characteristic of the remodeled vasculature in patients with pulmonary hypertension include increased stiffening of the elastic proximal pulmonary arteries, thickening of the intimal and/or medial layer of muscular arteries, development of vaso-occlusive lesions, and the appearance of cells expressing smooth muscle-specific markers in normally non-muscular small diameter vessels, resulting from proliferation and migration of pulmonary arterial smooth muscle cells and cellular transdifferentiation. The development of several animal models of pulmonary hypertension has provided the means to explore the mechanistic underpinnings of pulmonary vascular remodeling, although none of the experimental models currently used entirely replicates the pulmonary arterial hypertension observed in patients. Herein, we provide an overview of the histological abnormalities observed in humans with pulmonary hypertension and in preclinical models and discuss insights gained regarding several key signaling pathways contributing to the remodeling process. In particular, we will focus on the roles of ion homeostasis, endothelin-1, serotonin, bone morphogenetic proteins, Rho kinase, and hypoxia-inducible factor 1 in pulmonary arterial smooth muscle and endothelial cells, highlighting areas of cross-talk between these pathways and potentials for therapeutic targeting.

Topics: Animals; Bone Morphogenetic Proteins; Disease Models, Animal; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Hypoxia-Inducible Factor 1; Mice; Pulmonary Artery; Rats; rho-Associated Kinases; Serotonin; Signal Transduction

The right ventricle (RV) is not well suited to chronic pressure overload and often fails to adequately compensate. Mechanisms that allow the RV to respond to acute pressure overload often become maladaptive and contribute to its failure, including the effects of pulmonary hypertension on RV myocardial perfusion, the influence of interventricular dependence on RV function, and metabolic shifts in the RV myocardium from fatty acid to glycolysis. Medications to treat pulmonary hypertension have focused on pulmonary vasodilatation. Their effects on RV function may determine their effectiveness. How new medications affect right ventricular performance must be addressed.

Topics: Adaptation, Physiological; Calcium Channel Blockers; Chronic Disease; Endothelin Receptor Antagonists; Endothelin-1; Exercise; Familial Primary Pulmonary Hypertension; Heart Failure; Humans; Hypertension, Pulmonary; Phosphodiesterase 5 Inhibitors; Prostaglandins I; Ventricular Dysfunction, Right; Ventricular Remodeling

The demonstration that endothelin production is upregulated in pulmonary artery hypertension (PAH) served as the rationale for developing endothelin-receptor antagonists (ERAs) as a treatment for PAH. This article reviews the primary studies demonstrating efficacy of ERAs in PAH.. Multicenter, placebo-controlled trials and open-label extension studies.. Two orally active ERAs are currently approved for the treatment of PAH - the dual receptor antagonist bosentan, and the more selective ET(A) receptor antagonist ambrisentan-based on multicenter randomized clinical trials demonstrating efficacy and safety. Long-term experience with both agents supports maintenance of therapeutic effects in most patients. Adverse effects, including altered liver function and edema may occur and require careful monitoring.. Despite failure to demonstrate efficacy of ERAs in other cardiopulmonary conditions, ERAs have a major role in the treatment algorithm for PAH.

Topics: Administration, Oral; Animals; Antihypertensive Agents; Bosentan; Drug Design; Drug Monitoring; Endothelin Receptor Antagonists; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Phenylpropionates; Pyridazines; Sulfonamides

The term pulmonary arterial hypertension (PAH) describes a rare group of diseases characterized by raised pulmonary vascular resistance, resulting from vascular remodelling in the pre-capillary resistance arterioles (< 100 mm). Left untreated, patients die from right heart failure, with a mortality approaching most serious cancers. Endothelin-1(ET-1) is not only a potent vasoconstrictor, but causes proliferation of many of the vascular cells involved in vascular remodelling. Although produced mainly by the vascular endothelium, other cells such as smooth muscle, fibroblasts and macrophages are known sources of ET-1 when these cells are challenged by relevant stimuli. Plasma ET-1 levels are raised in patients with PAH and correlate with important clinical outcomes. Furthermore, ET-1 receptor antagonism has been demonstrated to improve both morbidity and mortality in conditions associated with PAH. We review the literature supporting the role for ET-1 in the pathogenesis of PAH.

Topics: Animals; Clinical Trials as Topic; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Receptors, Endothelin; Vascular Resistance

This multiple-ascending-dose study investigated safety, tolerability, pharmacokinetics, and pharmacodynamics, of macitentan, a new endothelin receptor antagonist (ERA) with sustained receptor binding and enhanced tissue penetration properties compared to other ERAs. Healthy male subjects (n = 32) received once daily oral doses of macitentan (1 - 30 mg) or placebo for 10 days. Administration of macitentan was safe and well tolerated. Macitentan had no effect on bile salts, suggesting an improved liver safety profile. The multiple-dose pharmacokinetics of macitentan were dose-proportional and were characterized by a median tmax and apparent elimination half-life varying from 6.0 to 8.5 and 14.3 to 18.5 hours, respectively, for the different doses and minimal accumulation. ACT-132577, a metabolite with lower potency than macitentan, had a half-life of about 48 hours and accumulated approximately 8.5-fold. Compared to placebo, administration of macitentan caused a dose-dependent increase in plasma ET-1 with maximum effects attained at 10 mg. A small dose-dependent increase in the 6β-hydroxycortisol/cortisol urinary excretion ratio was observed, although there were no statistically significant differences between treatments including placebo. Effects of macitentan on cytochrome P450 enzyme 3A4 should be further evaluated in dedicated studies. The present results support investigation of macitentan in the management of pulmonary arterial hypertension and ET-1-dependent pathologies.

Topics: Adult; Bile Acids and Salts; Dose-Response Relationship, Drug; Double-Blind Method; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hydrocortisone; Hypertension, Pulmonary; Male; Middle Aged; Pyrimidines; Sulfonamides; Young Adult

To study the impact of 24-week therapy with nebivolol in a dose of 5 mg/day on the clinical and functional status of patients with idiopathic pulmonary hypertension (IPH), echocardiographic parameters, and blood levels of vasoactive mediators and nitric oxide (NO) metabolite.. During continuous standard therapy comprising dihydropyridine calcium antagonists, warfarin, and diuretics, 12 patients with IPH and functional class (FC) II-III received nebivolol in a dose of 5 mg/day for 24 weeks. According to the data of right heart catheterization, all the patients had a positive acute pharmacological test with a vasodilator (NO). Six-minute walk test (6'WT), estimation of the Borg dyspnea index (BDI) and FC, transthoracic echocardiography (EchoCG), and measurements of the levels of NO metabolites, endothelin-1, (ET-1), thromboxane B2 (TxB2), and 6-keto-prostaglandin F1alpha (6-ketoPG F1alpha) were done at baseline and after 12 and 24 weeks of the therapy.. Following 24-week nebivolol treatment, there was a statistically significant increase in 6'WT distance (from 473 +/- 47.6 to 516.7 +/- 58.4 m; p < 0.0001) and a drop in BDI (from 3.4 +/- 2.2 to 1.1 +/- 0.7; p < 0.05) and FC (from 2.9 +/- 0.4 to 1.7 +/- 0.2; p < 0.05). Doppler EchoCG showed that pulmonary artery systolic pressure statistically significantly decreased (91.6 +/- 30 to 78.3 +/- 39 mm Hg; p = 0.05) at 12 weeks and slightly increased up to 83.2 +/- 32.4 mm Hg at 24 weeks. After 24-week treatment, the anteroposterior dimensions of the right ventricle (RV) statistically significantly reduced (from 4.4 +/- 0.6 to 3.8 +/- 1.2 cm; p < 0.05). The other EchoCG parameters remained substantially unchanged. There was a statistically reduction in the level of ET-1 (from 2.99 +/- 1.1 to 2.17 +/- 0.8 micromol/l; p < 0.05). The concentrations of 6-ketoPG Fla, TxB2, and NO metabolite remained substantially unchanged at 24 weeks of treatment with nebivolol. There were no adverse reactions requiring that the dose of the drug be discontinued or reduced. Heart rate tended to be lower at a 24-week follow-up. All the patients continued taking nebivolol after completion of the study.. Therapy with nebivolol in a dose of 5 mg/day for 24 weeks led to a significant functional improvement in the patients with IPH and reductions in RV dimensions and blood ET-1 levels. The therapy did not cause adverse reactions.

Topics: Adult; Benzopyrans; Drug Monitoring; Echocardiography, Doppler; Endothelin-1; Ethanolamines; Exercise Test; Familial Primary Pulmonary Hypertension; Female; Heart Failure; Humans; Hypertension, Pulmonary; Male; Middle Aged; Nebivolol; Nitric Oxide; Pilot Projects; Severity of Illness Index; Treatment Outcome; Vasodilator Agents

Inflammation is a major pathological feature of pulmonary arterial hypertension (PAH), particularly in the context of inflammatory conditions such as systemic sclerosis (SSc). The endothelin system and anti-endothelin A receptor (ET. Serum levels of anti-ET. Anti-ET. This study provides evidence for an anti-inflammatory role of ET

Topics: Animals; Autoantibodies; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertrophy, Right Ventricular; Inflammation; Mice; Pulmonary Arterial Hypertension; Receptor, Endothelin B; Scleroderma, Systemic

Pulmonary arterial hypertension (PAH) is characterized by abnormal outgrowth of pulmonary artery smooth muscle cells (PASMCs) of the media. Abundant expression of endothelin-1 (ET-1) and activated p38 mitogen-activated protein kinase (p38MAPK) has been observed in PAH patients. p38MAPK has been implicated in cell proliferation. An unspecified disturbance in bone morphogenetic protein (BMP) signaling may be involved in the development of PAH. Type I receptors (BMPR1A and BMPR1B) and type II receptor (BMPR2) transduce signals via two distinct pathways, i.e., canonical and non-canonical pathways, activating Smad1/5/8 and p38MAPK, respectively. BMPR1B expression was previously reported to be enhanced in the PASMCs of patients with idiopathic PAH. BMP15 binds specifically to BMPR1B. We assessed the effects of ET-1 on BMP receptor expression and cell proliferation. BMP2 increased BMPR1B expression in human PASMCs after pretreatment with ET-1 in vitro. Although BMP2 alone did not affect PASMC proliferation, BMP2 treatment after ET-1 pretreatment significantly accelerated PASMC proliferation. PH-797804, a selective p38MAPK inhibitor, abrogated this proliferation. Similarly, after ET-1 pretreatment, BMP15 significantly accelerated the proliferation of PASMCs, whereas stimulation with BMP15 alone did not. In conclusion, in PASMCs, ET-1 exposure under pathological conditions alters BMP signaling to activate p38MAPK, resulting in cell proliferation.

Topics: Bone Morphogenetic Proteins; Cell Proliferation; Cells, Cultured; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Myocytes, Smooth Muscle; p38 Mitogen-Activated Protein Kinases; Pulmonary Artery

Pulmonary arterial hypertension (PAH) is a fatal or life-threatening disorder characterized by elevated pulmonary arterial pressure and pulmonary vascular resistance. Abnormal vascular remodeling, including the proliferation and phenotypic modulation of pulmonary artery smooth muscle cells (PASMCs), represents the most critical pathological change during PAH development. Previous studies showed that miR-486 could reduce apoptosis in different cells; however, the role of miR-486 in PAH development or HPASMC proliferation and migration remains unclear. After 6 h of hypoxia treatment, miR-486-5p was significantly upregulated in HPASMCs. We found that miR-486-5p could upregulate the expression and secretion of ET-1. Furthermore, transfection with a miR-486-5p mimic could induce HPASMC proliferation and migration. We also found that miRNA-486-5p could downregulate the expression of SMAD2 and the phosphorylation of SMAD3. According to previous studies, the loss of SMAD3 may play an important role in miRNA-486-5p-induced HPASMC proliferation. Although the role of miRNA-486-5p in PAH in in vivo models still requires further investigation and confirmation, our findings show the potential roles and effects of miR-486-5p during PAH development.

Topics: Cell Movement; Cell Proliferation; Cells, Cultured; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; MicroRNAs; Myocytes, Smooth Muscle; Pulmonary Arterial Hypertension; Pulmonary Artery

Atrial arrhythmias are considered prominent phenomena in pulmonary arterial hypertension (PAH) resulting from atrial electrical and structural remodeling. Endothelin (ET)-1 levels correlate with PAH severity and are associated with atrial remodeling and arrhythmia. In this study, hemodynamic measurement, western blot analysis, and histopathology were performed in the control and monocrotaline (MCT, 60 mg/kg)-induced PAH rabbits. Conventional microelectrodes were used to simultaneously record the electrical activity in the isolated sinoatrial node (SAN) and right atrium (RA) tissue preparations before and after ET-1 (10 nM) or BQ-485 (an ET-A receptor antagonist, 100 nM) perfusion. MCT-treated rabbits showed an increased relative wall thickness in the pulmonary arterioles, mean cell width, cross-sectional area of RV myocytes, and higher right ventricular systolic pressure, which were deemed to have PAH. Compared to the control, the spontaneous beating rate of SAN-RA preparations was faster in the MCT-induced PAH group, which can be slowed down by ET-1. MCT-induced PAH rabbits had a higher incidence of sinoatrial conduction blocks, and ET-1 can induce atrial premature beats or short runs of intra-atrial reentrant tachycardia. BQ 485 administration can mitigate ET-1-induced RA arrhythmogenesis in MCT-induced PAH. The RA specimens from MCT-induced PAH rabbits had a smaller connexin 43 and larger ROCK1 and phosphorylated Akt than the control, and similar PKG and Akt to the control. In conclusion, ET-1 acts as a trigger factor to interact with the arrhythmogenic substrate to initiate and maintain atrial arrhythmias in PAH. ET-1/ET-A receptor/ROCK signaling may be a target for therapeutic interventions to treat PAH-induced atrial arrhythmias.

Topics: Animals; Arrhythmias, Cardiac; Connexin 43; Disease Models, Animal; Endothelin-1; Familial Primary Pulmonary Hypertension; Monocrotaline; Proto-Oncogene Proteins c-akt; Pulmonary Arterial Hypertension; Pulmonary Artery; Rabbits

Mutations in the bone morphogenetic protein receptor (BMPR2) gene have been observed in 70 % of patients with heritable pulmonary arterial hypertension (HPAH) and in 11-40 % with idiopathic PAH (IPAH). However, carriers of a BMPR2 mutation have only 20 % risk of developing PAH. Since inflammatory mediators are increased and predict survival in PAH, they could act as a second hit inducing the development of pulmonary hypertension in BMPR2 mutation carriers. Our specific aim was to determine whether inflammatory mediators could contribute to pulmonary vascular cell dysfunction in PAH patients with and without a BMPR2 mutation. Pulmonary microvascular endothelial cells (PMEC) and arterial smooth muscle cells (PASMC) were isolated from lung parenchyma of transplanted PAH patients, carriers of a BMPR2 mutation or not, and from lobectomy patients or lung donors. The effects of CRP and TNFα on mitogenic activity, adhesiveness capacity, and expression of adhesion molecules were investigated in PMECs and PASMCs. PMECs from BMPR2 mutation carriers induced an increase in PASMC mitogenic activity; moreover, endothelin-1 secretion by PMECs from carriers was higher than by PMECs from non-carriers. Recruitment of monocytes by PMECs isolated from carriers was higher compared to PMECs from non-carriers and from controls, with an elevated ICAM-1 expression. CRP increased adhesion of monocytes to PMECs in carriers and non-carriers, and TNFα only in carriers. PMEC from BMPR2 mutation carriers have enhanced adhesiveness for monocytes in response to inflammatory mediators, suggesting that BMPR2 mutation could generate susceptibility to an inflammatory insult in PAH.

Topics: Bone Morphogenetic Protein Receptors, Type II; C-Reactive Protein; Capillaries; Case-Control Studies; Cell Adhesion; Cell Line; Cells, Cultured; Endothelial Cells; Endothelin-1; Endothelium, Vascular; Familial Primary Pulmonary Hypertension; Heterozygote; Humans; Inflammation Mediators; Intercellular Adhesion Molecule-1; Myocytes, Smooth Muscle; Pulmonary Artery; Tumor Necrosis Factor-alpha

To explore the effects of renal sympathetic denervation (RSD) on pulmonary vascular remodeling in a model of pulmonary arterial hypertension (PAH).. According to the random number table, 24 beagles were randomized into control, PAH and PAH+RSD groups (n=8 each). The levels of neurohormone, echocardiogram and dynamics parameters were measured. Then 0.1 ml/kg dimethylformamide (control group) or 2 mg/kg dehydromonocrotaline (PAH and PAH+RSD groups) were injected. The PAH+RSD group underwent RSD after injection. At week 8 post-injection, the neurohormone levels, echocardiogram, dynamics parameters and pulmonary tissue morphology were observed.. The values of right ventricular systolic pressure (RVSP) and pulmonary arterial systolic pressure (PASP) in PAH and PAH+RSD groups were both significantly higher than those in control group ((42.8±8.7), (30.8±6.8) vs (23.2±5.7) mmHg (1 mmHg=0.133 kPa) and (45.1±11.2), (32.6±7.9) vs (24.7±7.1) mmHg). Meanwhile, the values of RVSP and PASP in PAH group were higher than those in PAH+RSD group (all P<0.01). The levels of serum angiotensin II (Ang II) and endothelin-1 significantly increased after 8 weeks in PAH dogs ((228±41) vs (113±34) pg/ml and (135±15) vs (77±7) pg/ml, all P<0.01). And Ang II and endothelin-1 were higher in lung tissues of PAH group ((65±10) and (96±10) pg/ml) than in those of control group ((38±7) and (54±6) pg/ml) and PAH+RSD group ((46±8) and (67±9) pg/ml) (all P<0.01). Pulmonary tissues had marked collagen hyperplasia and lamellar corpuscles of type 2 alveolar cells were damaged more severely in PAH dogs than in PAH+RSD dogs.. RSD suppresses pulmonary vascular remodeling and decreases pulmonary arterial pressure in experimental PAH. And the effect of RSD on PAH may contribute to decreased neurohormone levels.

Topics: Angiotensin II; Animals; Blood Pressure; Denervation; Dogs; Echocardiography; Endothelin-1; Familial Primary Pulmonary Hypertension; Hypertension, Pulmonary; Kidney; Lung; Monocrotaline; Pulmonary Artery; Sympathectomy; Vascular Remodeling

Krüppel-like factor 4 (KLF4) is a transcription factor expressed in the vascular endothelium, where it promotes anti-inflammatory and anticoagulant states, and increases endothelial nitric oxide synthase expression. We examined the role of endothelial KLF4 in pulmonary arterial (PA) hypertension (PAH). Mice with endothelial KLF4 knockdown were exposed to hypoxia for 3 weeks, followed by measurement of right ventricular and PA pressures, pulmonary vascular muscularization, and right ventricular hypertrophy. The effect of KLF4 on target gene expression was assessed in lungs from these mice, verified in vitro by small interfering RNA (siRNA) knockdown of KLF4, and further studied at the promoter level with cotransfection experiments. KLF4 expression was measured in lung tissue from patients with PAH and normal control subjects. We found that, after hypoxia, right ventricular and PA pressures were significantly higher in KLF4 knockdown animals than controls. Knockdown animals also had more severe pulmonary vascular muscularization and right ventricular hypertrophy. KLF4 knockdown resulted in increased pulmonary expression of endothelin-1 and decreased expression of endothelial nitric oxide synthase, endothelin receptor subtype B, and prostacyclin synthase. Concordant findings were observed in vitro, both with siRNA knockdown of KLF4 and promoter activity assays. Finally, KLF4 expression was reduced in lungs from patients with PAH. In conclusion, endothelial KLF4 regulates the transcription of genes involved in key pathways implicated in PAH, and its loss exacerbates pulmonary hypertension in response to chronic hypoxia in mice. These results introduce a novel transcriptional modulator of PAH, with the potential of becoming a new therapeutic target.

Topics: Animals; Arterial Pressure; Case-Control Studies; Cells, Cultured; Cytochrome P-450 Enzyme System; Disease Models, Animal; Endothelial Cells; Endothelin-1; Familial Primary Pulmonary Hypertension; Human Umbilical Vein Endothelial Cells; Humans; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Hypoxia; Intramolecular Oxidoreductases; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide Synthase Type III; Pulmonary Artery; Receptor, Endothelin B; RNA Interference; Time Factors; Transfection; Ventricular Function, Right; Ventricular Pressure

Both sildenafil and bosentan have been used clinically to treat pulmonary arterial hypertension. As these substances target different pathways to modulate vasoconstriction, we investigated the combined effects of both drug classes in isolated human pulmonary vessels.. Segments of pulmonary arteries (PA) and veins (PV) were harvested from 51 patients undergoing lobectomy. Contractile force was determined isometrically in an organ bath. Vessels were constricted with norepinephrine (NE) to determine effects of sildenafil. They were constricted with ET-1 to assess effects of bosentan, and with NE and ET-1 to evaluate the combination of both substances.. Sildenafil (1E-5 M) significantly reduced maximum constriction by NE of both PA (13.0 ± 11.1 vs. 34.9 ± 7.6% relative to KCl induced constriction; n = 6; p < 0.001) and PV (81.2 ± 34.2 vs 121.6 ± 20.8%; n = 6; p < 0.01) but did not affect basal tones. Bosentan (1E-5 M) significantly reduced maximum constriction of PV (56.6 ± 21.5 vs. 172.1 ± 30.0%; n = 6; p < 0.01) by ET-1 and led to a small but insignificant decrease of basal tone (p = 0.07). Bosentan almost completely abolished constriction of PA (1.0 ± 0.9 vs. 74.7 ± 25.7 %; n = 6; p < 0.001) by ET-1, but did not affect basal tone. Bosentan (1E-7 M) significantly attenuated combined ET-1/NE dose-response curves in PA (93.1 ± 47.4 vs. 125.3 ± 41.0%; n = 12; p < 0.001) whereas the effect of sildenafil (1E-5 M) was less pronounced (103.6 ± 20.2%; p < 0.05). Simultaneous administration of both substances showed a significantly greater reduction of maximum constriction in PA compared to individual administration (64.6 ± 26.3 %; p < 0.001).. Sildenafil only at its highest concentration was effective in suppressing NE induced pulmonary vessel contraction. Bosentan was able to completely suppress ET-1 induced contraction of PA and strongly attenuated contraction of PV. The present data suggest a benefit of sildenafil/bosentan combination therapy as they affect different pathways and may allow lower dosages.

Topics: Antihypertensive Agents; Bosentan; Dose-Response Relationship, Drug; Drug Therapy, Combination; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Norepinephrine; Phosphodiesterase 5 Inhibitors; Piperazines; Purines; Sildenafil Citrate; Sulfonamides; Sulfones; Vasoconstriction

Evidence is increasing of a link between interferon (IFN) and pulmonary arterial hypertension (PAH). Conditions with chronically elevated endogenous IFNs such as systemic sclerosis are strongly associated with PAH. Furthermore, therapeutic use of type I IFN is associated with PAH. This was recognized at the 2013 World Symposium on Pulmonary Hypertension where the urgent need for research into this was highlighted.. To explore the role of type I IFN in PAH.. Cells were cultured using standard approaches. Cytokines were measured by ELISA. Gene and protein expression were measured using reverse transcriptase polymerase chain reaction, Western blotting, and immunohistochemistry. The role of type I IFN in PAH in vivo was determined using type I IFN receptor knockout (IFNAR1(-/-)) mice. Human lung cells responded to types I and II but not III IFN correlating with relevant receptor expression. Type I, II, and III IFN levels were elevated in serum of patients with systemic sclerosis associated PAH. Serum interferon γ inducible protein 10 (IP10; CXCL10) and endothelin 1 were raised and strongly correlated together. IP10 correlated positively with pulmonary hemodynamics and serum brain natriuretic peptide and negatively with 6-minute walk test and cardiac index. Endothelial cells grown out of the blood of PAH patients were more sensitive to the effects of type I IFN than cells from healthy donors. PAH lung demonstrated increased IFNAR1 protein levels. IFNAR1(-/-) mice were protected from the effects of hypoxia on the right heart, vascular remodeling, and raised serum endothelin 1 levels.. These data indicate that type I IFN, via an action of IFNAR1, mediates PAH.

Topics: Animals; Cells, Cultured; Chemokine CXCL10; Disease Models, Animal; Endothelial Cells; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Interferon-alpha; Interferon-beta; Interferon-gamma; Lung; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Organ Culture Techniques; Receptor, Interferon alpha-beta; Scleroderma, Systemic; Signal Transduction

Despite recent and major progresses in the field of pulmonary vascular diseases pulmonary arterial hypertension (PAH) outcome still needs improvement. In parallel, several changes are observed in a disease that is no longer described as typically affecting young women. This is outlined in the most recent reports from PAH registries, where increasing age at the time of diagnosis is constantly described. Regardless the cause of this changing face, the quest for the perfect prognostic factor in PAH is ongoing. Among the numerous variables of interest, biomarkers are particularly attractive, as they do not require expertise or invasive procedure. This is the case for brain natriuretic peptide (BNP) and the inactive N-terminal cleavage product of its pro-hormone (NT-proBNP), which have proven to be reliable. This might also be the case for endothelin-1 (ET-1), a potent vasoactive peptide involved in the endothelin pathway and its biologically stable surrogate, carboxy-terminal pro-endothelin-1 (CT-proET1) that could independently predict 1-year event-free survival in PAH. Of course, further research is warranted to confirm these results. Yet, even if there are probably few chances, if any, to discover the "Holy Grail", researcher's efforts must continue. The combination of pertinent parameters in composite scores is indeed promising and emphasized in the most recent PAH guidelines. Clinicians would probably need to use a subtle combination of several biomarkers and clinical, functional, hemodynamic and right ventricular parameter criteria to drive the most ambitious treatment goals in a complex and life threatening disease.

Topics: Adult; Biomarkers; Disease-Free Survival; Endothelin-1; Familial Primary Pulmonary Hypertension; Female; Guideline Adherence; Humans; Natriuretic Peptide, Brain; Peptide Fragments; Prognosis; Treatment Outcome; Young Adult

Pulmonary hypertension (PH) is characterized by enhanced pulmonary artery smooth muscle cell (PASMC) proliferation leading to vascular remodeling. Although, multiple factors have been associated with pathogenesis of PH the underlying mechanisms are not fully understood. Here, we hypothesize that already very short exposure to hypoxia may activate molecular cascades leading to vascular remodeling. Microarray studies from lung homogenates of mice exposed to only 3h of hypoxia revealed endothelin-1 (ET-1) and connective tissue growth factor (CTGF) as the most upregulated genes, and the mitogen-activated protein kinase (MAPK) pathway as the most differentially regulated pathway. Evaluation of these results in vitro showed that ET-1 but not CTGF stimulation of human PASMCs increased DNA synthesis and expression of proliferation markers such as Ki67 and cell cycle regulator, cyclin D1. Moreover, ET-1 treatment elevated extracellular signal-regulated kinase (Erk)-dependent c-fos expression and phosphorylation of c-fos and c-jun transcription factors. Silencing of c-fos with siRNA abrogated the ET-1-induced proliferation of PASMCs. Expression and immunohistochemical analyses revealed higher levels of total and phosphorylated c-fos and c-jun in the vessel wall of lung samples of human idiopathic pulmonary arterial hypertension patents, hypoxia-exposed mice and monocrotaline-treated rats as compared to control subjects. These findings shed the light on the involvement of c-fos/c-jun in the proliferative response of PASMCs to ET-1 indicating that already very short hypoxia exposure leads to the regulation of mediators involved in vascular remodeling underlying PH.

Topics: Animals; Apoptosis; Biomarkers; Blotting, Western; Case-Control Studies; Cell Proliferation; Cells, Cultured; Endothelin-1; Extracellular Signal-Regulated MAP Kinases; Familial Primary Pulmonary Hypertension; Fluorescent Antibody Technique; Gene Expression Profiling; Humans; Hypoxia; Immunoenzyme Techniques; Lung; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Muscle, Smooth, Vascular; Oligonucleotide Array Sequence Analysis; Phosphorylation; Proto-Oncogene Proteins c-fos; Pulmonary Artery; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction

Accumulating evidence reveals that intrauterine growth retardation (IUGR) can cause varying degrees of pulmonary arterial hypertension (PAH) later in life. Moreover, epigenetics plays an important role in the fetal origin of adult disease. The goal of this study was to investigate the role of epigenetics in the development of PAH following IUGR.. The IUGR rats were established by maternal undernutrition during pregnancy. Pulmonary vascular endothelial cells (PVEC) were isolated from the rat lungs by magnetic-activated cell sorting (MACS). We investigated epigenetic regulation of the endothelin-1 (ET-1) gene in PVEC of 1-day and 6-week IUGR rats, and response of IUGR rats to hypoxia.. The maternal nutrient restriction increased the histone acetylation and hypoxia inducible factor-1α (HIF-1α) binding levels in the ET-1 gene promoter of PVEC in IUGR newborn rats, and continued up to 6 weeks after birth. These epigenetic changes could result in an IUGR rat being highly sensitive to hypoxia later in life, causing more significant PAH or pulmonary vascular remodeling.. These findings suggest that epigenetics is closely associated with the development of hypoxic PAH following IUGR, further providing a new insight for improved prevention and treatment of IUGR-related PAH.

Topics: Acetylation; Actins; Age Factors; Animals; Animals, Newborn; Binding Sites; Blood Pressure; Cell Separation; Disease Models, Animal; Endothelial Cells; Endothelin-1; Epigenesis, Genetic; Familial Primary Pulmonary Hypertension; Female; Fetal Growth Retardation; Flow Cytometry; Histones; Hypertension, Pulmonary; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Lung; Pregnancy; Promoter Regions, Genetic; Pulmonary Artery; Rats; Rats, Sprague-Dawley

We investigated gene transfer with human hepatocyte growth factor (HGF) to suppress pulmonary arterial hypertension (PAH) produced by an arteriovenous shunt in a rabbit model. The rabbit model of advanced PAH was used to show that HGF targets pulmonary arteriolar endothelial cells and inhibits disease progression. In the PAH rabbit model transfected with the HGF gene, hemodynamic abnormalities and right ventricular hypertrophy were prevented, as confirmed by invasive measurements and electrocardiographic examinations. In addition to augmented expression of HGF, an increased number of pulmonary arterioles were detected by immunohistochemical analysis. Western Blot and real-time reverse transcriptase-polymerase chain reaction indicated increased protein and mRNA levels of HGF and endothelial nitricoxide synthase (eNOS) in lungs after HGF transfection. Notably, exogenous HGF reduced lung expression of endothelin-1 (ET-1), which was critically involved in PAH-related pathologic changes. Our results suggested that HGF transfection suppresses PAH induced by shunt flow through enhanced expression of HGF with subsequent regulation of the concentrations of eNOS and ET-1 secreted by endothelial cells thereby promoting angiogenesis in injured lung tissue.

Topics: Animals; Arterioles; Arteriovenous Shunt, Surgical; Blotting, Western; Carotid Artery, Common; Disease Models, Animal; Disease Progression; Electrocardiography; Endothelial Cells; Endothelin-1; Familial Primary Pulmonary Hypertension; Genetic Therapy; Hemodynamics; Hepatocyte Growth Factor; Humans; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Immunohistochemistry; Jugular Veins; Lung; Male; Neovascularization, Physiologic; Nitric Oxide Synthase Type III; Rabbits; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Transfection

To investigate ghrelin levels in patients with idiopathic pulmonary arterial hypertension (IPAH) and the association of ghrelin with N-terminal brain natriuretic peptide (N-BNP), endothelin-1 (ET-1) and nitric oxide (NO).. Plasma ghrelin, N-BNP, ET-1 and NO were measured, and echocardiography was performed in 20 IPAH patients and in 20 control subjects matched for age, sex and body mass index.. Plasma ghrelin and NT-proBNP levels were significantly higher in IPAH patients compared with values in control subjects (p < 0.05). In IPAH patients, ghrelin levels correlated positively with N-BNP (r = 0.616, p = 0.004), NO (r = 0.464, p = 0.039), right ventricle diameter (RVD; r = 0.485, p = 0.030) and pulmonary arterial systolic pressure (PASP; r = 0.591, p = 0.006). N-BNP levels correlated positively with RVD (r = 0.551, p = 0.012) and ET-1 (r = 0.451, p = 0.046).. Plasma ghrelin levels were elevated in IPAH. Increased ghrelin levels correlated positively with N-BNP, PASP, RVD and NO, and N-BNP levels correlated positively with RVD and ET-1. Pulmonary vascular pathology is a complex imbalance of opposing forces. Ghrelin may not only provide a novel prognostic biomarker for IPAH but also be a potential new therapeutic strategy.

Topics: Adult; Biomarkers; Case-Control Studies; Cross-Sectional Studies; Endothelin-1; Familial Primary Pulmonary Hypertension; Female; Ghrelin; Humans; Hypertension, Pulmonary; Male; Natriuretic Peptide, Brain; Nitric Oxide; Peptide Fragments; Prognosis

The pressure-loaded right ventricle (RV) adversely affects left ventricular (LV) function. We recently found that these ventricular-ventricular interactions lead to LV myocardial fibrosis through transforming growth factor-β1 (TGF-β1) signaling. We investigated the mechanisms mediating biventricular fibrosis in RV afterload and their potential modification by angiotensin receptor blockade. An adjustable pulmonary artery band (PAB) was placed in rabbits. In sham-operated control rabbits, the band was left uninflated (n = 6). In the RV afterload group, the PAB was sequentially inflated to generate systemic RV pressure at 28 days (n = 8). In a third group, the PAB was inflated to systemic levels, and the angiotensin receptor blocker losartan was added (n = 6). Five weeks after surgery, the animals were killed for assessments of biventricular hypertrophy, fibrosis, apoptosis, and the components of their signaling pathways. PAB animals developed biventricular hypertrophy, fibrosis, and apoptosis, versus sham rabbits, in which these conditions were decreased with losartan. RV and LV TGF-β1, connective tissue growth factor (CTGF) (CCN2), endothelin-1 (ET-1), endothelin receptor B, and matrix metalloproteinase 2/9 mRNA levels were increased in PAB animals versus sham animals, and decreased with losartan. Given the marked biventricular CTGF up-regulation in PAB and down-regulation with losartan, we investigated CTGF signaling. RV and LV Smad 2/3/4 protein levels and LV RhoA mRNA levels were increased with PAB and reduced with losartan. In conclusion, isolated RV afterload induces biventricular fibrosis and apoptosis, which are reduced by angiotensin receptor blockade. Adverse ventricular-ventricular interactions induced by isolated RV afterload appear to be mediated through TGF-β1-CTGF and ET-1 pathways.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Apoptosis; Connective Tissue Growth Factor; Endothelin-1; Familial Primary Pulmonary Hypertension; Fibrosis; Hypertension; Hypertension, Pulmonary; Losartan; Male; Matrix Metalloproteinase 2; Rabbits; Receptor, Endothelin B; RNA, Messenger; Signal Transduction; Transforming Growth Factor beta1; Ventricular Dysfunction, Right; Ventricular Remodeling

Pulmonary arterial hypertension (PAH) is a rare, deadly condition. Although risk stratification is extremely important for assessment of prognosis and to guide therapy, there is lack of evidence concerning the role of novel biomarkers. In a pivotal study, we sought to comparatively investigate the predictive power of several new biomarkers in PAH.. Patients with prevalent PAH were enrolled in the study protocol, which included clinical, functional and echocardiographic assessment. Blood samples were collected at baseline for determination of NT-proBNP, CT-proET-1, MR-proANP, MR-proADM, copeptin and troponin I. Patients were clinically followed-up up to 12 months for first occurrence of hospital admission due to PAH-related clinical worsening, heart/lung transplantation or all-cause mortality.. Among the 28 included patients the pre-specified end-point occurred in 8 (29% event rate). There were higher baseline levels of CT-proET-1, copeptin, MR-proANP, NT-proBNP and troponin I in patients who reached the composite end-point. They also had larger right atria. In multivariate Cox regression, CT-proET-1 was the only biomarker associated with increased hazard of reaching the primary composite end-point (hazard ratio per tertile increase = 10.1; 95% CI 2.0 to 50.6).. CT-proET-1 provided prognostic information independent of other biomarkers. Importantly, we have provided the first evidence that CT-proET-1 may be superior to commonly used biomarkers.

Topics: Adult; Aged; Atrial Natriuretic Factor; Biomarkers; Cohort Studies; Echocardiography; Endothelin-1; Familial Primary Pulmonary Hypertension; Female; Follow-Up Studies; Glycopeptides; Humans; Hypertension, Pulmonary; Kaplan-Meier Estimate; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Predictive Value of Tests; Prognosis; Prospective Studies; Regression Analysis; Risk Factors; Troponin I

Chronic anticoagulation is a standard of care in idiopathic pulmonary arterial hypertension (IPAH). However, hemostatic abnormalities in this disease remain poorly understood. Therefore, we aimed to study markers of thrombogenesis and fibrinolysis in patients with IPAH.. We studied 27 consecutive patients (67% female) with IPAH aged 50.0 years (IQR: 41.0-65.0) and 16 controls without pulmonary hypertension. Prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin (TAT) complexes were measured to assess thrombogenesis; tissue-type plasminogen activator (tPA) antigen and plasmin-anti-plasmin complex to characterize activation of fibrinolysis; plasminogen activator inhibitor 1 (PAI-1) to measure inhibition of fibrinolysis; and endothelin-1 (ET-1) and interleukin-6 (IL-6) to assess endothelial activation and systemic inflammation, respectively. In addition, in treatment-naive IPAH patients these markers were assessed after 3 months of PAH-specific therapies.. TPA (10.1[6.8-15.8] vs 5.2[3.3-7.3] ng/ml, p<0.001), plasmin-anti-plasmin (91.5[60.3-94.2] vs 55.8[51.1-64.9] ng/ml, p<0.001), IL-6 (4.9[2.5-7.9] vs 2.1[1.3-3.8] pg/ml, p=0.001) and ET-1 (3.7 [3.3-4.5] vs 3.4[3.1-3.5], p= 0.03) were higher in patients with IPAH than in controls. In IPAH patients plasmin-anti-plasmin and tPA correlated positively with IL-6 (r=0.39, p=0.04 and r=0.63, p<0.001, respectively) and ET-1 (r=0.55, p=0.003 and r=0.59, p=0.001, respectively). No correlation was found between tPA or plasmin-anti-plasmin and markers of thrombogenesis. Plasmin-anti-plasmin decreased after 3 months of PAH specific therapy while the other markers remained unchanged.. In the present study we showed that markers of fibrynolysis were elevated in patients with IPAH however we did not find a clear evidence for increased thrombogenesis in this group of patients. Fibrinolysis, inflammation, and endothelial activation were closely interrelated in IPAH.

Topics: Adult; Aged; Endothelin-1; Endothelium, Vascular; Familial Primary Pulmonary Hypertension; Female; Fibrinolysis; Humans; Inflammation; Interleukin-6; Male; Middle Aged; Prothrombin; Thrombin; Tissue Plasminogen Activator

To address if baseline endothelin-1 (ET-1) plasma levels might predict clinical worsening (CW) in patients with idiopathic pulmonary hypertension (IPAH) treated with bosentan.. Forty-four consecutive patients with IPAH (WHO classes II-III) were included in this study. After an initial assessment (clinical status, pulmonary hemodynamics, samples for adrenomedullin (ADM), ET-1 and brain natriuretic peptide (BNP) plasma levels), patients were treated with bosentan and followed-up for CW.. We observed CW in 24 patients. Actuarial rates of freedom from CW were 74% at 1 year, 56% at 2 years, and 43% at 3 years. Patients with CW had a worse WHO functional class (II/III; no-CW 14/6 vs CW 5/19, p=0.002), six-minute walk-test distance (no-CW 439+94 m vs CW 385+82 m, p=0.04), mean pulmonary artery pressure (no-CW 47.4+10.6mm Hg vs CW 56+12.6mm Hg, p=0.02) and pulmonary vascular resistance (PVR no-CW 12.5+4.8 WU vs CW 16.4+6.3 WU, p=0.03) than the no-CW group. Moreover ET-1 (no-CW 14.1+4.2 pg/ml vs CW 21.3+6.3 pg/ml, p=0.0001), ADM (no-CW 14.9+7 pg/ml vs CW 21.5+10.4 pg/ml p=0.002) and BNP (no-CW 82.8+35.3 pg/ml vs CW 115.4+39.6 pg/ml, p=0.007) plasma levels were significantly higher in the CW group than in the no-CW group. The multivariate Cox proportional hazards model identified WHO class III (RR 4.6, 95%CI 14.6-1.45), ET-1 plasma levels (RR 1.1, 95%CI 2.05-1.01) and PVR (RR 1.2, 95%CI 1.3-1.03) as independent risk factors for CW.. These data confirm the high rate of CW in patients with IPAH treated with bosentan and document the impact of the endothelin system on CW of these patients.

Topics: Adult; Aged; Antihypertensive Agents; Biomarkers; Bosentan; Endothelin-1; Exercise Test; Familial Primary Pulmonary Hypertension; Female; Follow-Up Studies; Humans; Hypertension, Pulmonary; Male; Middle Aged; Prospective Studies; Sulfonamides; Treatment Outcome

We sought to investigate the experimental therapeutic effects and mechanisms of iptakalim, a new adenosine triphosphate (ATP)-sensitive potassium channel (K(ATP)) opener, on monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) and right heart ventricle remodeling in rats.. Rats were injected with a single dose (50 mg/kg, ip) of MCT and given iptakalim (1, 3, and 9 mg/kg·per d, orally [po]) or saline for 28 days. The hemodynamic and morphometric parameters were assessed. Tissue and plasma samples were collected for histological and molecular analysis.. Treatment with iptakalim at daily oral doses of 1, 3, and 9 mg/kg from the day of MCT injection attenuated the high right ventricle systolic pressure (RVSP) and the increased weight ratio of right ventricle (RV) to left ventricle (LV) plus septum (S) (RV/(LV+S)), decreased heart rate (HR) and decreased mean arterial pressure (MAP), inhibited the RV myocardial tissue cell apoptosis, and the RV myocardial cell B-type natriuretic peptide (BNP) protein expression. Iptakalim also decreased the serum levels of nitric oxide (NO), endothelin 1 (ET-1), BNP, and the levels of NO, ET-1, and tumor necrosis factor-alpha (TNF-α) in the lung tissue.. These results indicate that iptakalim prevents MCT-induced PAH and RV remodeling and its mechanisms are related to inhibiting the pathological increases in NO, ET-1, BNP, and TNF-α, and Iptakalim may be a promising candidate for the treatment of PAH.

Topics: Animals; Endothelin-1; Familial Primary Pulmonary Hypertension; Hemodynamics; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; KATP Channels; Lung; Male; Monocrotaline; Natriuretic Peptide, Brain; Nitric Oxide; Propylamines; Rats; Rats, Wistar

Pulmonary arterial hypertension (PAH) is a progressive and a life-threatening disease with its high morbidity and mortality ratios. On searching for new shining targets in pathogenesis, we noticed, in our previous studies, urotensin-II (UII) in systemic sclerosis with potent angiogenic and pro-fibrotic features. Owing to the mimicking properties of UII with endothelin-1 (ET1), we attempted to investigate the effect of palosuran in a PAH rat model. Thirty rats were randomly divided into three groups, with each group comprising 10 rats: group 1 (control group) received the vehicle subcutaneously, instead of monocrotaline (MCT) and vehicle; group 2 (MCT group) received subcutaneous MCT and vehicle; and group 3 (MCT + palosuran group) received subcutaneous MCT and palosuran. Serum UII, ET1, transforming growth factor-β1 (TGF-β1) levels, pulmonary arteriolar pathology of different diameter vessels, and cardiac indices were evaluated. The ET1, TGF-β1, and UII levels were significantly diminished in the treatment group, similar to the controls (p < 0.001). Right ventricular hypertrophy index and mean pulmonary arterial pressure scores were also significantly reduced in the treatment group (p = 0.001). Finally, in the 50-125-μm diameter arterioles, in contrast to Groups 3 and 1, there was a statistically significant thickness (p < 0.01) in the arteriolar walls of rats in Group 2. The treatment effect on arteries of more than 125-μm diameters was found to be valuable but not significant. Owing to its healing effect on hemodynamic, histological, and biochemical parameters of MCT-induced PAH, palosuran as an antagonist of UII might be an optional treatment alternative for PAH.

Topics: Animals; Arterial Pressure; Arterioles; Endothelin-1; Familial Primary Pulmonary Hypertension; Hemodynamics; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Male; Monocrotaline; Pulmonary Artery; Quinolines; Rats; Rats, Wistar; Transforming Growth Factor beta1; Urea; Urotensins

Pulmonary arterial hypertension (PAH) is a fatal disease for which no cure is yet available. The leading cause of death in PAH is right ventricular (RV) failure. Previously, the TNF receptor superfamily member fibroblast growth factor-inducible molecule 14 (Fn14) has been associated with different fibrotic diseases. However, so far there is no study demonstrating a causal role for endogenous Fn14 signaling in RV or LV heart disease. The purpose of this study was to determine whether global ablation of Fn14 prevents RV fibrosis and remodeling improving heart function. Here, we provide evidence for a causative role of Fn14 in pulmonary artery banding (PAB)-induced RV fibrosis and dysfunction in mice. Fn14 expression was increased in the RV after PAB. Mice lacking Fn14 (Fn14(-/-)) displayed substantially reduced RV fibrosis and dysfunction following PAB compared to wild-type littermates. Cell culture experiments demonstrated that activation of Fn14 induces collagen expression via RhoA-dependent nuclear translocation of myocardin-related transcription factor-A (MRTF-A)/MAL. Furthermore, activation of Fn14 in vitro caused fibroblast proliferation and myofibroblast differentiation, which corresponds to suppression of PAB-induced RV fibrosis in Fn14(-/-) mice. Moreover, our findings suggest that Fn14 expression is regulated by endothelin-1 (ET-1) in cardiac fibroblasts. We conclude that Fn14 is an endogenous key regulator in cardiac fibrosis and suggest this receptor as potential new target for therapeutic interventions in heart failure.

Topics: Animals; Apoptosis Regulatory Proteins; Blotting, Western; Cell Differentiation; Cell Proliferation; Collagen; Cytokine TWEAK; Endothelin-1; Familial Primary Pulmonary Hypertension; Fibrosis; Fluorescent Antibody Technique; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Immunohistochemistry; Membrane Proteins; Mice; Mice, Knockout; Myocardium; Myofibroblasts; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Receptors, Tumor Necrosis Factor; Signal Transduction; Trans-Activators; Transcription Factors; Tumor Necrosis Factors; TWEAK Receptor; Up-Regulation; Ventricular Dysfunction, Right

This study analyses the frequency and the potential role of two polymorphisms, the +134del/insA, located in the gene encoding for Endothelin-1 (EDN1), and the His323His in the gene encoding for Endothelin receptor type A (EDNRA) in a cohort of 98 consecutive patients with pulmonary arterial hypertension from two different Cardiology Units (Mid-South of Italy), and in 100 healthy Caucasian subjects randomly recruited from the same area. Cardiac anatomy and function were analysed by non invasive diagnostic imaging techniques (Echocardiography standard m-mode, 2D, colour-Doppler) and by invasive studies (cardiac catheterization). Molecular screening of the region of interest was performed by automated sequencing. At univariate analysis, patients with the His323His TT genotype show a lower cardiac index (2 ± 0.6 vs. 2.3 ± 0.6; p = 0.05) and a higher indexed pulmonary vascular resistance (18.8 ± 9.6 vs. 14.2 ± 6.9; p = 0.01) at cardiac catheterization. A logistic multivariate model shows idiopathic disease (p = 0.01; OR = 3.8; CI = 1.3-11) and indexed pulmonary vascular resistances (p = 0.01; OR = 1.1; CI = 1-1.2) as independent predictors of TT genotype. Our findings may suggest a potential link between specific genotypes in the EDNRA gene and susceptibility for PAH.

Topics: Adult; Aged; Endothelin-1; Familial Primary Pulmonary Hypertension; Female; Humans; Hypertension, Pulmonary; Italy; Male; Middle Aged; Molecular Sequence Data; Polymorphism, Genetic; Receptor, Endothelin A

Medial hypertrophy of pulmonary arterioles during pulmonary arterial hypertension (PAH) in humans is associated with enhanced proliferation of smooth muscle cells (SMCs). Elevated matrix metalloproteinase (MMP)-2 has been found in pulmonary artery SMCs (PA-SMCs) in humans with idiopathic PAH, leading to the hypothesis that MMP-2 contributes to the proliferation and migration of vascular SMCs in the pathogenesis of PAH. Rapidly growing meat-type (broiler) chickens provide a model of spontaneous PAH. The present study was conducted to determine whether MMP-2 is involved in the medial hypertrophy of pulmonary arterioles in this model. Cultured PA-SMCs from normal birds were used to evaluate the effect of MMPs on cell proliferation. Gelatin zymography showed that endothelin (ET)-1-induced proliferation of PA-SMCs was concomitant with increased pro- and active MMP-2 production. Reverse transcription PCR demonstrated upregulation of MMP-2 mRNA. However, PA-SMC proliferation was inhibited by the MMP inhibitors doxycycline and cis-9-octadecenoyl-N-hydroxylamide. In vivo experiments revealed a significant increase of MMP-2 expression in hypertrophied pulmonary arterioles of PAH broiler chickens, which was positively correlated with wall thickness and medial hypertrophy. MMP-2 may contribute to medial hypertrophy in pulmonary arterioles during PAH in broiler chickens by enhancing the proliferation of vascular SMCs.

Topics: Animals; Arterioles; Chickens; Doxycycline; Electrophoresis, Polyacrylamide Gel; Endothelin-1; Familial Primary Pulmonary Hypertension; Gene Expression Regulation, Enzymologic; Hydroxamic Acids; Hypertension, Pulmonary; Hypertrophy; Lung; Matrix Metalloproteinase 2; Matrix Metalloproteinase Inhibitors; Myocytes, Smooth Muscle; Poultry Diseases; Pulmonary Artery; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sodium Chloride

Pulmonary arterial hypertension (PAH) is characterized, in part, by decreased endothelial nitric oxide (NO(·)) production and elevated levels of endothelin-1. Endothelin-1 is known to stimulate endothelial nitric oxide synthase (eNOS) via the endothelin-B receptor (ET(B)), suggesting that this signaling pathway is perturbed in PAH. Endothelin-1 also stimulates adrenal aldosterone synthesis; in systemic blood vessels, hyperaldosteronism induces vascular dysfunction by increasing endothelial reactive oxygen species generation and decreasing NO(·) levels. We hypothesized that aldosterone modulates PAH by disrupting ET(B)-eNOS signaling through a mechanism involving increased pulmonary endothelial oxidant stress.. In rats with PAH, elevated endothelin-1 levels were associated with elevated aldosterone levels in plasma and lung tissue and decreased lung NO(·) metabolites in the absence of left-sided heart failure. In human pulmonary artery endothelial cells, endothelin-1 increased aldosterone levels via peroxisome proliferator-activated receptor gamma coactivator-1α/steroidogenesis factor-1-dependent upregulation of aldosterone synthase. Aldosterone also increased reactive oxygen species production, which oxidatively modified cysteinyl thiols in the eNOS-activating region of ET(B) to decrease endothelin-1-stimulated eNOS activity. Substitution of ET(B)-Cys405 with alanine improved ET(B)-dependent NO(·) synthesis under conditions of oxidant stress, confirming that Cys405 is a redox-sensitive thiol that is necessary for ET(B)-eNOS signaling. In human pulmonary artery endothelial cells, mineralocorticoid receptor antagonism with spironolactone decreased aldosterone-mediated reactive oxygen species generation and restored ET(B)-dependent NO(·) production. Spironolactone or eplerenone prevented or reversed pulmonary vascular remodeling and improved cardiopulmonary hemodynamics in 2 animal models of PAH in vivo.. Our findings demonstrate that aldosterone modulates an ET(B) cysteinyl thiol redox switch to decrease pulmonary endothelium-derived NO(·) and promote PAH.

Topics: Aldosterone; Animals; Cells, Cultured; Cysteine; Disease Models, Animal; Endothelial Cells; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Male; Mineralocorticoid Receptor Antagonists; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidation-Reduction; Oxidative Stress; Pulmonary Artery; Pulmonary Wedge Pressure; Rats; Rats, Sprague-Dawley; Receptor, Endothelin B; Spironolactone; Sulfhydryl Compounds

Chronic right ventricular (RV) pressure overload results in pathologic RV hypertrophy and diminished RV function. Although aortic constriction has been shown to improve systolic function in acute RV failure, its effect on RV responses to chronic pressure overload is unknown.. Adjustable vascular banding devices were placed on the main pulmonary artery and descending aorta. In 5 animals (sham group), neither band was inflated. In 9 animals (PAB group), only the pulmonary arterial band was inflated, with adjustments on a weekly basis to generate systemic or suprasystemic RV pressure at 28 days. In 9 animals, both pulmonary arterial and aortic devices were inflated (PAB + AO group), the pulmonary arterial band as for the PAB group and the aortic band adjusted to increase proximal systolic blood pressure by approximately 20 mm Hg. Effects on the functional performance were assessed 5 weeks after surgery by conductance catheters, followed by histologic and molecular assessment.. Contractile performance was significantly improved in the PAB + AO group versus the PAB group for both ventricles. Relative to sham-operated animals, both banding groups showed significant differences in myocardial histologic and molecular responses. Relative to the PAB group, the PAB + AO group showed significantly decreased RV cardiomyocyte diameter, decreased RV collagen content, and reduced RV expression of endothelin receptor type B, matrix metalloproteinase 9, and transforming growth factor β genes.. Aortic constriction in an experimental model of chronic RV pressure overload not only resulted in improved biventricular systolic function but also improved myocardial remodeling. These data suggest that chronically increased left ventricular afterload leads to a more physiologically hypertrophic response in the pressure-overloaded RV.

Topics: Animals; Aorta; Arterial Pressure; Chronic Disease; Collagen; Collagenases; Connective Tissue Growth Factor; Constriction; Disease Models, Animal; Endothelin-1; Familial Primary Pulmonary Hypertension; Heart Failure; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Myocardial Contraction; Myocardium; Pulmonary Artery; Rabbits; Receptors, Endothelin; Recovery of Function; Time Factors; Transforming Growth Factor beta; Ventricular Function, Left; Ventricular Function, Right; Ventricular Pressure; Ventricular Remodeling

Topics: Endothelin-1; Familial Primary Pulmonary Hypertension; Female; Humans; Hypertension, Pulmonary; Male; Polymorphism, Genetic; Receptor, Endothelin A

Pulmonary arterial hypertension (PAH) is a rare but fatal condition in which raised pulmonary vascular resistance leads to right heart failure and death. Endothelin-1 is a potent endogenous vasoconstrictor, which is considered to be central to many of the events that lead to PAH, and is an important therapeutic target in the treatment of the condition. In many cases of PAH, the aetiology is unknown but inflammation is increasingly thought to play an important role and viruses have been implicated in the development of disease. The Toll Like Receptors (TLRs) play a key role in innate immune responses by initiating specific anti-bacterial and anti-viral defences in recognition of signature molecular motifs on the surface of invading pathogens. In this study, we set out to examine the expression of bacterial and viral TLRs in human pulmonary artery smooth muscle cells and to establish whether their activation could be relevant to PAH. We found that the viral TLR3 and bacterial TLRs 4 and 6 were most abundantly expressed in human pulmonary artery smooth muscle cells. Using specific TLR ligands, we found that activation of TLRs 3 and 4 resulted in IL-8 release by human pulmonary artery smooth muscle cells but that only TLR3 stimulation resulted in IP10 and endothelin-1 release. These data suggest that human pulmonary artery smooth muscle cells express significant levels of viral TLR3 and respond to its activation by releasing endothelin-1. This may have importance in understanding the association between viruses and the development of PAH.

Topics: Cells, Cultured; Chemokines; Cytokines; Endothelin-1; Familial Primary Pulmonary Hypertension; Gene Expression; Humans; Hypertension, Pulmonary; Interleukin-8; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Poly I-C; Receptors, Cytokine; Toll-Like Receptor 3; Tumor Necrosis Factor-alpha

Two endothelin receptor antagonists (ERAs), bosentan and ambrisentan, are currently approved for the treatment of pulmonary arterial hypertension (PAH), a devastating disease involving an activated endothelin system and aberrant contraction and proliferation of pulmonary arterial smooth muscle cells (PASMC). The novel ERA macitentan has recently concluded testing in a Phase III morbidity/mortality clinical trial in PAH patients. Since the association and dissociation rates of G protein-coupled receptor antagonists can influence their pharmacological activity in vivo, we used human PASMC to characterize inhibitory potency and receptor inhibition kinetics of macitentan, ambrisentan and bosentan using calcium release and inositol-1-phosphate (IP(1)) assays. In calcium release assays macitentan, ambrisentan and bosentan were highly potent ERAs with K(b) values of 0.14 nM, 0.12 nM and 1.1 nM, respectively. Macitentan, but not ambrisentan and bosentan, displayed slow apparent receptor association kinetics as evidenced by increased antagonistic potency upon prolongation of antagonist pre-incubation times. In compound washout experiments, macitentan displayed a significantly lower receptor dissociation rate and longer receptor occupancy half-life (ROt(1/2)) compared to bosentan and ambrisentan (ROt(1/2):17 minutes versus 70 seconds and 40 seconds, respectively). Because of its lower dissociation rate macitentan behaved as an insurmountable antagonist in calcium release and IP(1) assays, and unlike bosentan and ambrisentan it blocked endothelin receptor activation across a wide range of endothelin-1 (ET-1) concentrations. However, prolongation of the ET-1 stimulation time beyond ROt(1/2) rendered macitentan a surmountable antagonist, revealing its competitive binding mode. Bosentan and ambrisentan behaved as surmountable antagonists irrespective of the assay duration and they lacked inhibitory activity at high ET-1 concentrations. Thus, macitentan is a competitive ERA with significantly slower receptor dissociation kinetics than the currently approved ERAs. Slow dissociation caused insurmountable antagonism in functional PASMC-based assays and this could contribute to an enhanced pharmacological activity of macitentan in ET-1-dependent pathologies.

Topics: Animals; Bosentan; Calcium; CHO Cells; Clinical Trials, Phase III as Topic; Cricetinae; Endothelin Receptor Antagonists; Endothelin-1; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Inositol Phosphates; Myocytes, Smooth Muscle; Phenylpropionates; Pulmonary Artery; Pyridazines; Pyrimidines; Receptors, Endothelin; Sulfonamides

It is unclear why some patients, who undergo complete repair or palliative surgery for congenital heart disease (CHD), still develop irreversible pulmonary artery hypertension (PAH). There is no consensus to preoperationally assess the reversible and irreversible pulmonary vasculopathy seen in PAH.. The peri-operative pulmonary hemodynamic data of 16 CHD patients (reversible PAH, n = 6; irreversible PAH, n = 10) were analyzed. The lung biopsies were also performed during surgery for defining histopathological characteristics as well as immunohistochemical expression of endothelin-1 (ET-1), endothelin-1 receptors (ETR), and its downstream signaling markers in the small pulmonary arteries and arterioles. Neointimal formation and neoangiogenesis was characterized by increased intimal layer immunoreactivity for α-SMA, Factor VIII, CD34, and VEGF. Neointimal formation was found in 90% of patients and neoangiogenesis was found in 80% of patients with irreversible PAH. Neither was present in the reversible PAH group and the control group. Expression of ET-1 and ETR in the neointimal layer of the pulmonary arterioles was upregulated in irreversible PAH, and immunoreactivity of phospho-Akt, phospho-ERK1/2, and phospho-mTOR was also increased in irreversible PAH.. Increased expression of ET-1, ETR, and activation of signaling pathways were observed in the pulmonary arteries and arterioles of irreversible PAH patients associated with CHD. Activation of these pathways might in turn lead to neointimal formation and neoangiogenesis and thus might contribute to irreversible pulmonary vascular abnormalities.

Topics: Actins; Adolescent; Adult; Antigens, CD34; Biopsy; Cell Proliferation; China; Endothelin-1; Factor VIII; Familial Primary Pulmonary Hypertension; Female; Heart Defects, Congenital; Hemodynamics; Humans; Hypertension, Pulmonary; Immunohistochemistry; Male; Middle Aged; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neovascularization, Pathologic; Phosphorylation; Proto-Oncogene Proteins c-akt; Pulmonary Artery; Receptor, Endothelin A; Receptor, Endothelin B; Retrospective Studies; Signal Transduction; TOR Serine-Threonine Kinases; Tunica Intima; Up-Regulation; Vascular Endothelial Growth Factor A; Young Adult

Pulmonary arterial hypertension (PAH) is characterized by a progressive increase in pulmonary vascular resistance and elevation of pulmonary arterial pressure, leading to right ventricular failure and eventual death. Currently, no curative therapy for PAH is available, and the overall prognosis is very poor. Recently, direct activators of soluble guanylyl cyclase (sGC) have been tested as a novel therapeutic modality in experimental models of pulmonary arterial hypertension (PAH).. In this study, we used in vitro and in vivo models to evaluate the therapeutic potential of 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), a dual functioning chemical, as a direct activator of guanylyl cyclase and an inhibitor of hypoxia-inducible factor-1.. We analyzed the effects of YC-1 on cell proliferation and the levels of p21 and p53 in human pulmonary artery smooth muscle cells (HPASMCs) under hypoxia. We also determined the effects of YC-1 on expression of endothelin-1 (ET-1) and phosphorylation status of endothelial nitric oxide synthase (eNOS) at Ser(1179) in human pulmonary artery endothelial cells (HPAECs) under hypoxia. In mice, hypoxic PAH was induced by exposure to normobaric hypoxic conditions for 28 days. To assess preventive or therapeutic effects, randomized mice were subjected to once daily i.p. injections of YC-1 for the entire hypoxic period (5 mg/kg) or for the last seven days of a 28-day hypoxic period (5 and 10 mg/kg). On day 28, we measured the right ventricular systolic pressure (RVSP) and determined the degrees of right ventricular hypertrophy (RVH) and vascular remodeling.. In HPASMCs, YC-1 inhibited hypoxia-induced proliferation and induction of p53 and p21 in a concentration-dependent manner. Also, YC-1 suppressed the hypoxia-induced expression of ET-1 mRNA and dephosphorylation of eNOS at Ser(1179) in HPAECs. In the preventive in vivo model, a daily dose of 5 mg/kg YC-1 significantly prevented the elevation of RVSP, development of RVH, and pulmonary vascular remodeling, which were caused by hypoxic exposure. In the therapeutic model, YC-1 at daily doses of 5 and 10 mg/kg alleviated RVH and pulmonary vascular remodeling but did not prevent the elevation of RVSP.. Our results indicate that YC-1 prevents the development of hypoxia-induced PAH in a preventive model and alleviates RVH and pulmonary vascular remodeling in a therapeutic model. Therefore, these data imply that YC-1 has therapeutic potential for use in a single or combination therapy for PAH.

Topics: Animals; Cell Proliferation; Cells, Cultured; Cyclin-Dependent Kinase Inhibitor p21; Endothelin-1; Enzyme Activators; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Hypoxia; Indazoles; Male; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Nitric Oxide Synthase Type III; Pulmonary Artery; Tumor Suppressor Protein p53

Abnormalities of signalling for the transforming growth factor beta (TGFβ) family of peptides, including bone morphogenic proteins (BMP), have been described in heritable pulmonary arterial hypertension (PAH). TGFβ can modulate synthesis of the vasoconstrictor and mitogen, endothelin-1 (ET-1), a mediator that contributes to the pathogenesis of PAH. BMP-9 is a circulating peptide recently recognized to affect endothelial function. The stimuli for increased microvascular endothelial production of ET-1 in PAH are unknown. We therefore studied the effects of BMP-9 on ET-1 production by human lung blood microvascular endothelial cells (HMVEC-LBl) in vitro. In vitro, BMP-9 increased ET-1 production by HMVEC-LBl. The effect was identical to TGFβ-1, but BMP-9 and TGFβ-1 combined further increased ET-1 levels by 29%. As compared to TGFβ-1, BMP-9 induced more potent and rapid phosphorylation of Smad 1/5, the downstream signalling molecules of the activin-like kinase 1 (ALK-1) receptor. Moreover, as has been previously shown for endothelial cells of other origin, BMP-9 also induced Smad 2 phosphorylation in HMVEC-LBl. In conclusion, BMP-9 stimulates ET-1 production by HMVEC-LBl in vitro. BMP-9 signals via several Smad pathways. These studies provide novel mechanisms for the potentiation of PAH.

Topics: Cells, Cultured; Endothelial Cells; Endothelin-1; Extracellular Signal-Regulated MAP Kinases; Familial Primary Pulmonary Hypertension; Growth Differentiation Factor 2; Humans; Hypertension, Pulmonary; Lung; Microvessels; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Receptor, Endothelin B; Signal Transduction; Smad1 Protein; Smad2 Protein; Smad5 Protein; Time Factors; Transforming Growth Factor beta1; Up-Regulation

Systemic Sclerosis (SSc) is a multisystem connective tissue disease characterized by fibrosis of the skin and internal organs and extensive vasculopathy. We report a case of a 41 year-old white woman with a 10 year-history of limited scleroderma, who developed the rare combination of Scleroderma Renal Crisis (SRC) and Systemic Sclerosis related Pulmonary Arterial Hypertension (SScPAH) in the same time. Although the patient received the proposed antihypertensive treatment, the renal function did not recover, and she initiated on renal replacement therapy. SRC and SScPAH are two aspects of SSc vasculopathy characterized by endothelial dysfunction mediated by endothelin-1 and other vasoactive hormones. Further new studies with therapies directed towards the underlying mechanisms of SRC (i.e. endothelin-receptor antagonists), which are proven helpful in SScPAH, should take place to establish new therapeutic options and improve prognosis of these patients, for which our therapeutic armamentarium is currently poor.

Topics: Acute Kidney Injury; Adult; Endothelin-1; Endothelium, Vascular; Familial Primary Pulmonary Hypertension; Female; Humans; Hypertension, Pulmonary; Renal Replacement Therapy; Scleroderma, Systemic