semaxinib and Pulmonary-Arterial-Hypertension

Pulmonary arterial hypertension (PAH) is a chronic, incurable condition characterized by pulmonary vascular remodeling, perivascular inflammation, and right heart failure. Regulatory T cells (Tregs) stave off autoimmunity, and there is increasing evidence for their compromised activity in the inflammatory milieu of PAH. Abnormal Treg function is strongly correlated with a predisposition to PAH in animals and patients. Athymic Treg-depleted rats treated with SU5416, an agent causing pulmonary vascular injury, develop PAH, which is prevented by infusing missing CD4

Topics: Animals; Autoimmunity; Endothelium, Vascular; Humans; Indoles; Pulmonary Arterial Hypertension; Pyrroles; Rats; Sex Characteristics; T-Lymphocytes, Regulatory; Vascular System Injuries

As time progresses, our understanding of disease pathology is propelled forward by technological advancements. Much of the advancements that aid in understanding disease mechanics are based on animal studies. Unfortunately, animal models often fail to recapitulate the entirety of the human disease. This is especially true with animal models used to study pulmonary arterial hypertension (PAH), a disease with two distinct phases. The first phase is defined by nonspecific medial and adventitial thickening of the pulmonary artery and is commonly reproduced in animal models, including the classic models (ie, hypoxia-induced pulmonary hypertension and monocrotaline lung injury model). However, many animal models, including the classic models, fail to capture the progressive, or second, phase of PAH. This is a stage defined by plexogenic arteriopathy, resulting in obliteration and occlusion of the small- to mid-sized pulmonary vessels. Each of these two phases results in severe pulmonary hypertension that directly leads to right ventricular hypertrophy, decompensated right-sided heart failure, and death. Fortunately, newly developed animal models have begun to address the second, more severe, side of PAH and aid in our ability to develop new therapeutics. Moreover, p38 mitogen-activated protein kinase activation emerges as a central molecular mediator of plexiform lesions in both experimental models and human disease. Therefore, this review will focus on plexiform arteriopathy in experimental animal models of PAH.

Topics: Animals; Disease Models, Animal; Disease Progression; Humans; Hypoxia; Indoles; MAP Kinase Signaling System; Mice; Mice, Knockout; Pulmonary Arterial Hypertension; Pulmonary Artery; Pyrroles; Rats

The NLRP3 inflammasome in macrophages is known to promote infection-related vascular growth, and NLRP3 inflammasome activation interacts with PAH. STING is a crucial inflammatory reaction link that can increase the overexpression of NLRP3. However, the expression and effect of STING in PAH have not been elucidated. We examined the expression and articulation of STING in PAH and researched its hidden mechanism.. A SU5416 plus hypoxia (Su/Hy)-induced rat model of PAH was constructed to examine STING activation. Su/Hy induced PAH rats were given a prophylactic injection of STING the inhibitor C-176. After modeling, hemodynamic changes, right ventricular hypertrophy index, lung morphological features, inflammasome activation, and proinflammatory cytokine secretion levels were assessed. In addition, the STING agonist DMXAA or inhibitor C-176 was used to interfere with LPS-induced BMDMs, NLRP3 inflammasome activation and cytokine secretion were examined, and the effect on PASMCs was evaluated in a coculture system.. STING expression increased significantly in the lung tissue of Su/Hy-treated PAH rats compared with normoxia-treated rats. Moreover, STING inhibitors can alleviate the Su/Hy-induced increase in pulmonary artery pressure and restrain the activation of the NLRP3 inflammasome and proinflammatory cytokines. In vitro experiments confirmed that STING affected the expression of the NLRP3 inflammasome and the secretion of inflammatory cytokines in BMDMs and promoted the proliferation of PASMCs in the coculture system.. Our study shows that STING is activated in Su/Hy-induced PAH and boosts the actuation of the macrophage NLRP3 inflammasome to advance the inflammatory response and vascular proliferation in rats with Su/Hy-induced pulmonary hypertension.

Topics: Animals; Cytokines; Hypoxia; Inflammasomes; Macrophages; NLR Family, Pyrin Domain-Containing 3 Protein; Pulmonary Arterial Hypertension; Rats

Topics: Administration, Inhalation; Administration, Oral; Animals; Collagen; Disease Models, Animal; Epoprostenol; Heart; Hemodynamics; Hypoxia; Indoles; Male; Myocardium; Phosphodiesterase 5 Inhibitors; Pulmonary Arterial Hypertension; Pulmonary Artery; Pyrroles; Rats, Sprague-Dawley; Sildenafil Citrate; Vascular Remodeling; Vasodilator Agents

Pulmonary arterial hypertension (PAH) is a progressive disease of the pulmonary vasculature that leads to right ventricular failure. Skeletal muscle maladaptations limit physical activity and may contribute to disease progression. The role of alarmin/inflammatory signaling in PAH respiratory muscle dysfunction is unknown. We hypothesized that diaphragm mitochondrial and contractile functions are impaired in SU5416/hypoxia-induced pulmonary hypertension due to increased systemic IL-33 signaling. We induced pulmonary hypertension in adult C57Bl/6 J (WT) and ST2 (IL1RL1) gene ablated mice by SU5416/hypoxia (SuHx). We measured diaphragm fiber mitochondrial respiration, inflammatory markers, and contractile function ex vivo. SuHx reduced coupled and uncoupled permeabilized myofiber respiration by ∼40 %. During coupled respiration with complex I substrates, ST2

Topics: Animals; Diaphragm; Disease Models, Animal; Hypertension, Pulmonary; Hypoxia; Indoles; Interleukin-1 Receptor-Like 1 Protein; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitochondria; Mitochondrial Diseases; Muscle Contraction; Protein Kinase Inhibitors; Pulmonary Arterial Hypertension; Pyrroles

Topics: Animals; Disease Models, Animal; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Hypoxia; Indoles; Mineralocorticoid Receptor Antagonists; Pulmonary Arterial Hypertension; Pyrroles; Rats; Ventricular Dysfunction, Right

Pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressure and right heart failure. Selective pulmonary vasodilators have improved the prognosis of PAH; however, they are not able to reverse pulmonary vascular remodeling. Therefore, a search for new treatment agents is required. H-1337 is an isoquinoline-sulfonamide compound that inhibits multiple serine/threonine kinases, including Rho-associated protein kinase (ROCK) and mammalian target of rapamycin (mTOR). Here, we investigated the effects of H-1337 on pulmonary hypertension and remodeling in the pulmonary vasculature and right ventricle in experimental PAH induced by SU5416 and hypoxia exposure. H-1337 and H-1337M1 exerted inhibitory effects on ROCK and Akt. H-1337 inhibited the phosphorylation of myosin light chain and mTOR and suppressed the proliferation of smooth muscle cells in vitro. H-1337 treatment also suppressed the phosphorylation of myosin light chain and mTOR in the pulmonary vasculature and decreased right ventricular systolic pressure and the extent of occlusive pulmonary vascular lesions. Furthermore, H-1337 suppressed aggravation of right ventricle hypertrophy. In conclusion, our data demonstrated that inhibition of ROCK and mTOR pathways with H-1337 suppressed the progression of pulmonary vascular remodeling, pulmonary hypertension, and right ventricular remodeling.

Topics: Animals; Cell Proliferation; Heart Ventricles; Humans; Hypoxia; Indoles; Isoquinolines; Lung; Male; Metabolome; Myosin Light Chains; Phosphorylation; Proto-Oncogene Proteins c-akt; Pulmonary Arterial Hypertension; Pyrroles; Rats, Sprague-Dawley; Sulfonamides; TOR Serine-Threonine Kinases; Vascular Remodeling

Monoamine oxidases (MAOs), a class of enzymes bound to the outer mitochondrial membrane, are important sources of reactive oxygen species. Increased MAO-A activity in endothelial cells and cardiomyocytes contributes to vascular dysfunction and progression of left heart failure. We hypothesized that inhibition of MAO-A can be used to treat pulmonary arterial hypertension (PAH) and right ventricular (RV) failure. MAO-A levels in lung and RV samples from patients with PAH were compared with levels in samples from donors without PAH. Experimental PAH was induced in male Sprague-Dawley rats by using Sugen 5416 and hypoxia (SuHx), and RV failure was induced in male Wistar rats by using pulmonary trunk banding (PTB). Animals were randomized to receive either saline or the MAO-A inhibitor clorgyline at 10 mg/kg. Echocardiography and RV catheterization were performed, and heart and lung tissues were collected for further analysis. We found increased MAO-A expression in the pulmonary vasculature of patients with PAH and in experimental experimental PAH induced by SuHx. Cardiac MAO-A expression and activity was increased in SuHx- and PTB-induced RV failure. Clorgyline treatment reduced RV afterload and pulmonary vascular remodeling in SuHx rats through reduced pulmonary vascular proliferation and oxidative stress. Moreover, clorgyline improved RV stiffness and relaxation and reversed RV hypertrophy in SuHx rats. In PTB rats, clorgyline had no direct clorgyline had no direct effect on the right ventricle effect. Our study reveals the role of MAO-A in the progression of PAH. Collectively, these findings indicated that MAO-A may be involved in pulmonary vascular remodeling and consecutive RV failure.

Topics: Animals; Clorgyline; Disease Models, Animal; Disease Progression; Heart Ventricles; Humans; Hypertrophy, Right Ventricular; Indoles; Monoamine Oxidase; Oxidative Stress; Pulmonary Arterial Hypertension; Pulmonary Artery; Pyrroles; Rats; Vascular Remodeling; Vascular Stiffness; Vasodilation

Pulmonary arterial hypertension is characterized by abnormal proliferation of pulmonary artery smooth muscle cells and vascular remodeling, which leads to right ventricular (RV) failure. Bsg (Basigin) is a transmembrane glycoprotein that promotes myofibroblast differentiation, cell proliferation, and matrix metalloproteinase activation. CyPA (cyclophilin A) binds to its receptor Bsg and promotes pulmonary artery smooth muscle cell proliferation and inflammatory cell recruitment. We previously reported that Bsg promotes cardiac fibrosis and failure in the left ventricle in response to pressure-overload in mice. However, the roles of Bsg and CyPA in RV failure remain to be elucidated. Approach and Results: First, we found that protein levels of Bsg and CyPA were upregulated in the heart of hypoxia-induced pulmonary hypertension (PH) in mice and monocrotaline-induced PH in rats. Furthermore, cardiomyocyte-specific Bsg-overexpressing mice showed exacerbated RV hypertrophy, fibrosis, and dysfunction compared with their littermates under chronic hypoxia and pulmonary artery banding. Treatment with celastrol, which we identified as a suppressor of Bsg and CyPA by drug screening, decreased proliferation, reactive oxygen species, and inflammatory cytokines in pulmonary artery smooth muscle cells. Furthermore, celastrol treatment ameliorated RV systolic pressure, hypertrophy, fibrosis, and dysfunction in hypoxia-induced PH in mice and SU5416/hypoxia-induced PH in rats with reduced Bsg, CyPA, and inflammatory cytokines in the hearts and lungs.. These results indicate that elevated Bsg in pressure-overloaded RV exacerbates RV dysfunction and that celastrol ameliorates RV dysfunction in PH model animals by suppressing Bsg and its ligand CyPA. Thus, celastrol can be a novel drug for PH and RV failure that targets Bsg and CyPA. Graphic Abstract: A graphic abstract is available for this article.

Topics: Animals; Antihypertensive Agents; Basigin; Cyclophilin A; Disease Models, Animal; Humans; Hypoxia; Indoles; Mice; Mice, Transgenic; Myocytes, Cardiac; Pentacyclic Triterpenes; Pulmonary Arterial Hypertension; Pyrroles; Rats; Triterpenes; Ventricular Dysfunction, Right

Pulmonary hypertension (PH) causes cardiac hypertrophy in the right ventricle (RV) and eventually leads to RV failure due to persistently elevated ventricular afterload. We hypothesized that the mechanical stress on the RV associated with increased afterload impairs vasodilator function of the right coronary artery (RCA) in PH. Coronary vascular response was assessed using microangiography with synchrotron radiation (SR) in two well-established PH rat models, monocrotaline injection or the combined exposure to chronic hypoxia and vascular endothelial growth factor receptor blockade with Su5416 (SuHx model). In the SuHx model, the effect of the treatment with the nonselective endothelin-1 receptor antagonist (ERA), macitentan, was also examined. Myocardial viability was determined in SuHx model rats, using

Topics: Animals; Antihypertensive Agents; Coronary Angiography; Coronary Vessels; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Hypertrophy, Right Ventricular; Hypoxia; Indoles; Monocrotaline; Predictive Value of Tests; Pulmonary Arterial Hypertension; Pyrimidines; Pyrroles; Rats, Sprague-Dawley; Severity of Illness Index; Sulfonamides; Synchrotrons; Vasodilation; Ventricular Dysfunction, Right; Ventricular Function, Right; Ventricular Remodeling

It is generally considered that there is an increase in glycolysis in the hypertrophied right ventricle (RV) during pulmonary hypertension (PH), which leads to a decrease in glucose oxidation through the tricarboxylic acid (TCA) cycle. Although recent studies have demonstrated that fatty acid (FA) and glucose accumulated in the RV of patients with PH, the details of this remain to be elucidated. The purpose of the current study was to assess the metabolic remodeling in the RV of rats with PH using a metabolic analysis. Male rats were treated with the vascular endothelial growth factor receptor blocker SU5416 followed by 3 weeks of hypoxic conditions and 5 weeks of normoxic conditions (Su/Hx rats). Hemodynamic measurements were conducted, and the RV was harvested for the measurement of metabolites. A metabolomics analysis revealed a decreasing trend in the levels of alanine, argininosuccinic acid and downstream TCA cycle intermediates, including fumaric and malic acid and an increasing trend in branched‑chain amino acids (BCAAs) in Su/Hx rats compared with the controls; however, no trends in glycolysis were indicated. The FA metabolomics analysis also revealed a decreasing trend in the levels of long‑chain acylcarnitines, which transport FA from the cytosol to the mitochondria and are essential for beta‑oxidation. The current study demonstrated that the TCA cycle was less activated because of a decreasing trend in the expression of fumaric acid and malic acid, which might be attributable to the expression of adenylosuccinic acid and argininosuccinic acid. These results suggest that dysregulated BCAA metabolism and a decrease in FA oxidation might contribute to the reduction of the TCA cycle reactions.

Topics: Animals; Citric Acid Cycle; Fatty Acids; Glucose; Heart Ventricles; Humans; Hypertrophy, Right Ventricular; Hypoxia; Indoles; Oxidation-Reduction; Pulmonary Arterial Hypertension; Pyrroles; Rats; Rats, Sprague-Dawley; Ventricular Remodeling

Right ventricular (RV) dysfunction is a significant prognostic determinant of morbidity and mortality in pulmonary arterial hypertension (PAH). Despite the importance of RV function in PAH, the underlying molecular mechanisms of RV dysfunction secondary to PAH remain unclear. We aim to identify and compare molecular determinants of RV failure using RNA sequencing of RV tissue from 2 clinically relevant animal models of PAH.. We performed RNA sequencing on RV from rats treated with monocrotaline or Sugen with hypoxia/normoxia. PAH and RV failure were confirmed by catheterization and echocardiography. We validated the RV transcriptome results using quantitative real-time polymerase chain reaction, immunofluorescence, and Western blot. Immunohistochemistry and immunofluorescence were performed on human RV tissue from control (n=3) and PAH-induced RV failure patients (n=5).. We identified similar transcriptomic profiles of RV from monocrotaline- and Sugen with hypoxia-induced RV failure. Pathway analysis showed genes enriched in epithelial-to-mesenchymal transition, inflammation, and metabolism. Histological staining of human RV tissue from patients with RV failure secondary to PAH revealed significant RV fibrosis and endothelial-to-mesenchymal transition, as well as elevated cellular communication network factor 2 (top gene implicated in epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition) expression in perivascular areas compared with normal RV.. Transcriptomic signature of RV failure in monocrotaline and Sugen with hypoxia models showed similar gene expressions and biological pathways. We provide translational relevance of this transcriptomic signature using RV from patients with PAH to demonstrate evidence of epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition and protein expression of cellular communication network factor 2 (CTGF [connective tissue growth factor]). Targeting specific molecular mechanisms responsible for RV failure in monocrotaline and Sugen with hypoxia models may identify novel therapeutic strategies for PAH-associated RV failure.

Topics: Aged; Aged, 80 and over; Angiogenesis Inhibitors; Animals; Disease Models, Animal; Epithelial-Mesenchymal Transition; Female; Gene Expression Profiling; Heart Failure; Heart Ventricles; Humans; Hypoxia; Indoles; Male; Middle Aged; Monocrotaline; Pulmonary Arterial Hypertension; Pyrroles; Rats; Real-Time Polymerase Chain Reaction; RNA-Seq; Transcriptome; Ventricular Dysfunction, Right; Ventricular Remodeling

The mechanism of vascular remodelling in pulmonary arterial hypertension (PAH) remains unclear. Hence, defining the origin of cells constituting intractable vascular lesions in PAH is expected to facilitate therapeutic progress. Herein, we aimed to evaluate the origin of intractable vascular lesions in PAH rodent models via bone marrow (BM) and orthotopic lung transplantation (LT).. To trace BM-derived cells, we prepared chimeric rats transplanted with BM cells from green fluorescent protein (GFP) transgenic rats. Male rats were transplanted with lungs obtained from female rats and vice versa. Pulmonary hypertension was induced in the transplanted rats via Sugen5416 treatment and subsequent chronic hypoxia (Su/Hx).. In the chimeric Su/Hx models, GFP-positive cells were observed in the pulmonary vascular area. Moreover, the right ventricular systolic pressure was significantly lower compared with wild-type Su/Hx rats without BM transplantation (P = 0.009). PAH suppression was also observed in rats that received allograft transplanted BM transplantation. In male rats that received LT and Su/Hx, BM-derived cells carrying the Y chromosome were also detected in neointimal occlusive lesions of the transplanted lungs received from female rats.. BM-derived cells participate in pulmonary vascular remodelling in the Su/Hx rat model, whereas BM transplantation may contribute to suppression of development of PAH.

Topics: Angiogenesis Inhibitors; Animals; Bone Marrow Cells; Bone Marrow Transplantation; Cell Tracking; Disease Models, Animal; Female; Hypoxia; Indoles; Lung; Male; Neointima; Pulmonary Arterial Hypertension; Pulmonary Artery; Pyrroles; Rats; Transplantation Chimera; Vascular Remodeling

Pulmonary arterial hypertension (PAH), is a fatal disease characterized by a pseudo-malignant phenotype. We investigated the expression and the role of the receptor tyrosine kinase Axl in experimental (i.e., monocrotaline and Su5416/hypoxia treated rats) and clinical PAH. In vitro Axl inhibition by R428 and Axl knock-down inhibited growth factor-driven proliferation and migration of non-PAH and PAH PASMCs. Conversely, Axl overexpression conferred a growth advantage. Axl declined in PAECs of PAH patients. Axl blockage inhibited BMP9 signaling and increased PAEC apoptosis, while BMP9 induced Axl phosphorylation. Gas6 induced SMAD1/5/8 phosphorylation and ID1/ID2 increase were blunted by BMP signaling obstruction. Axl association with BMPR2 was facilitated by Gas6/BMP9 stimulation and diminished by R428. In vivo R428 aggravated right ventricular hypertrophy and dysfunction, abrogated BMPR2 signaling, elevated pulmonary endothelial cell apoptosis and loss. Together, Axl is a key regulator of endothelial BMPR2 signaling and potential determinant of PAH.

Topics: Angiogenesis Inhibitors; Animals; Bone Morphogenetic Protein Receptors, Type II; Gene Expression Regulation; Indoles; Male; Monocrotaline; Pulmonary Arterial Hypertension; Pyrroles; Rats, Inbred WKY; Rats, Sprague-Dawley; Receptor Protein-Tyrosine Kinases

Endothelial cells dysfunction is one of the hallmark pathogenic features of pulmonary arterial hypertension (PAH). Paeoniflorin (PF) is a monoterpene glycoside with endothelial protection, vasodilation, antifibrotic, anti-inflammatory and antioxidative properties. However, the effects of PF on PAH remain unknown.. Here, we investigated the efficacy of PF in the SU5416/hypoxia (SuHx) rat model of PAH. Human pulmonary arterial endothelial cells (HPAECs) were exposed to 1% O. Hemodynamics analysis showed that prophylactic treatment with PF (300 mg/kg i.g. daily for 21 days) significantly inhibited chronic hypoxia/SU5416-induced elevations of right ventricular systolic pressure (RVSP) and right ventricular hypertrophy index in rats. Meanwhile, PF significantly reduced pulmonary vascular remodeling, as well as alleviated collagen deposition in lungs and right ventricles in SuHx rats. Additionally, PF inhibited SuHx-induced down-regulation of endothelial marker (vascular endothelial cadherin) and up-regulation of mesenchymal markers (fibronectin and vimentin) in lung, suggesting that PF could inhibit SuHx-induced endothelial-to-mesenchymal transition (EndMT) in lung. Further in vitro studies confirmed that PF treatment suppressed hypoxia-induced EndMT in HPAECs, which was abolished by the knockdown of bone morphogenetic protein receptor type 2 (BMPR2) in HPAECs.. Taken together, our findings suggest that PF ameliorates BMPR2 down-regulation-mediated EndMT and thereafter alleviates SuHx-induced PAH in rats.

Topics: Animals; Cells, Cultured; Chronic Disease; Disease Models, Animal; Endothelial Cells; Epithelial-Mesenchymal Transition; Glucosides; Humans; Hypoxia; Indoles; Injections, Subcutaneous; Male; Monoterpenes; Oxygen; Pulmonary Arterial Hypertension; Pyrroles; Rats; Rats, Sprague-Dawley

Pulmonary arterial hypertension (PAH) is a lethal disease characterized by a progressive increase in pulmonary artery pressure due to an increase in vessel tone and occlusion of vessels. The endogenous vasodilator prostacyclin and its analogs are used as therapeutic agents for PAH. However, their pharmacological effects on occlusive vascular remodeling have not been elucidated yet. Selexipag is a recently approved, orally available and selective prostacyclin receptor agonist with a non-prostanoid structure. In this study, we investigated the pharmacological effects of selexipag on the pathology of chronic severe PAH in Sprague-Dawley and Fischer rat models in which PAH was induced by a combination of injection with the vascular endothelial growth factor receptor antagonist Sugen 5416 and exposure to hypoxia (SuHx). Oral administration of selexipag for three weeks significantly improved right ventricular systolic pressure and right ventricular (RV) hypertrophy in Sprague-Dawley SuHx rats. Selexipag attenuated the proportion of lung vessels with occlusive lesions and the medial wall thickness of lung arteries, corresponding to decreased numbers of Ki-67-positive cells and a reduced expression of collagen type 1 in remodeled vessels. Administration of selexipag to Fischer rats with SuHx-induced PAH reduced RV hypertrophy and mortality caused by RV failure. These effects were probably based on the potent prostacyclin receptor agonistic effect of selexipag on pulmonary vessels. Selexipag has been approved and is used in the clinical treatment of PAH worldwide. It is thought that these beneficial effects of prostacyclin receptor agonists on multiple aspects of PAH pathology contribute to the clinical outcomes in patients with PAH.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Acetamides; Animals; Cell Proliferation; Collagen Type I; Disease Models, Animal; Heart Ventricles; Hemodynamics; Hypertrophy, Right Ventricular; Hypoxia; Indoles; Lung; Male; Pulmonary Arterial Hypertension; Pyrazines; Pyrroles; Rats, Sprague-Dawley; Receptors, Epoprostenol; Systole; Vascular Remodeling

Topics: Angiogenesis Inhibitors; Animals; Drug Therapy, Combination; Hypoxia; Indoles; Male; Pulmonary Arterial Hypertension; Pyrroles; Rats; Rats, Wistar; Receptors, Thromboxane A2, Prostaglandin H2; Sildenafil Citrate; Treatment Outcome; Vasodilator Agents

Topics: Animals; Emphysema; Hypertension, Pulmonary; Hypoxia; Indoles; Phenotype; Pulmonary Arterial Hypertension; Pyrroles; Rats

Topics: Animals; Emphysema; Hypertension, Pulmonary; Hypoxia; Indoles; Phenotype; Pulmonary Arterial Hypertension; Pyrroles; Rats

Pulmonary arterial hypertension (PAH) is a morbid disease characterized by progressive right ventricle (RV) failure due to elevated pulmonary artery pressures (PAP). In PAH, histologically complex vaso-occlusive lesions in the pulmonary vasculature contribute to elevated PAP. However, the mechanisms underlying dysfunction of the microvascular endothelial cells (MVECs) that comprise a significant portion of these lesions are not well understood. We recently showed that MVECs isolated from the Sugen/hypoxia (SuHx) rat experimental model of PAH (SuHx-MVECs) exhibit increases in migration/proliferation, mitochondrial reactive oxygen species (ROS; mtROS) production, intracellular calcium levels ([Ca

Topics: Angiogenesis Inhibitors; Animals; Calcium; Cells, Cultured; Endothelial Cells; Hypoxia; Indoles; Lung; Male; Mitochondria; Oxygen Consumption; Pulmonary Arterial Hypertension; Pyrroles; Rats; Rats, Wistar; Reactive Oxygen Species; Vascular Remodeling

Pulmonary arterial hypertension (PAH) is associated with increased levels of circulating growth factors and corresponding receptors such as platelet derived growth factor, fibroblast growth factor and vascular endothelial growth factor. Nintedanib, a tyrosine kinase inhibitor targeting primarily these receptors, is approved for the treatment of patients with idiopathic pulmonary fibrosis. Our objective was to examine the effect of nintedanib on proliferation of human pulmonary microvascular endothelial cells (MVEC) and assess its effects in rats with advanced experimental pulmonary hypertension (PH).. Proliferation was assessed in control and PAH MVEC exposed to nintedanib. PH was induced in rats by subcutaneous injection of Sugen (SU5416) and subsequent exposure to 10% hypoxia for 4 weeks (SuHx model). Four weeks after re-exposure to normoxia, nintedanib was administered once daily for 3 weeks. Effects of the treatment were assessed with echocardiography, right heart catheterization, and histological analysis of the heart and lungs. Changes in extracellular matrix production was assessed in human cardiac fibroblasts stimulated with nintedanib. Decreased proliferation with nintedanib was observed in control MVEC, but not in PAH patient derived MVEC. Nintedanib treatment did not affect right ventricular (RV) systolic pressure or total pulmonary resistance index in SuHx rats and had no effects on pulmonary vascular remodelling. However, despite unaltered pressure overload, the right ventricle showed less dilatation and decreased fibrosis, hypertrophy, and collagen type III with nintedanib treatment. This could be explained by less fibronectin production by cardiac fibroblasts exposed to nintedanib.. Nintedanib inhibits proliferation of pulmonary MVECs from controls, but not from PAH patients. While in rats with experimental PH nintedanib has no effects on the pulmonary vascular pathology, it has favourable effects on RV remodelling.

Topics: Adult; Animals; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Endothelial Cells; Extracellular Matrix; Female; Fibroblasts; Fibrosis; Humans; Indoles; Male; Myocardium; Protein Kinase Inhibitors; Pulmonary Arterial Hypertension; Pulmonary Artery; Pyrroles; Rats, Sprague-Dawley; Vascular Remodeling; Ventricular Function, Right; Ventricular Remodeling; Young Adult

Right ventricular failure (RVF) is a common cause of death in patients suffering from pulmonary arterial hypertension (PAH). The current treatment for PAH only moderately improves symptoms, and RVF ultimately occurs. Therefore, it is necessary to develop new treatment strategies to protect against right ventricle (RV) maladaptation despite PAH progression. In this study, we hypothesize that local mesenchymal stem cell (MSC) delivery via a novel bioscaffold can improve RV function despite persistent PAH. To test our hypothesis, we induced PAH in adult rats with SU5416 and chronic hypoxia exposure; treated with rat MSCs delivered by intravenous injection, intramyocardial injection, or epicardial placement of a bioscaffold; and then examined treatment effectiveness by in vivo pressure-volume measurement, echocardiography, histology, and immunohistochemistry. Our results showed that compared with other treatment groups, only the MSC-seeded bioscaffold group resulted in RV functional improvement, including restored stroke volume, cardiac output, and improved stroke work. Diastolic function indicated by end-diastolic pressure-volume relationship was improved by the local MSC treatments or bioscaffold alone. Cardiomyocyte hypertrophy and RV fibrosis were both reduced, and von Willebrand factor expression was restored by the MSC-seeded bioscaffold treatment. Overall, our study suggests a potential new regenerative therapy to rescue the pressure-overload failing RV with persistent pulmonary vascular disease, which may improve quality of life and/or survival of PAH patients. NEW & NOTEWORTHY We explored the effects of mesenchymal stem cell-seeded bioscaffold on right ventricles (RVs) of rats with established pulmonary arterial hypertension (PAH). Some beneficial effects were observed despite persistent PAH, suggesting that this may be a new therapy for RV to improve quality of life and/or survival of PAH patients.

Topics: Animals; Arterial Pressure; Cells, Cultured; Disease Models, Animal; Fibrosis; Hypertrophy, Right Ventricular; Hypoxia; Indoles; Male; Mesenchymal Stem Cell Transplantation; Myocardial Contraction; Myocardium; Pulmonary Arterial Hypertension; Pulmonary Artery; Pyrroles; Rats, Sprague-Dawley; Recovery of Function; Regeneration; Tissue Scaffolds; Ventricular Dysfunction, Right; Ventricular Function, Right; Ventricular Remodeling; von Willebrand Factor

Topics: Adolescent; Adult; Aged; Animals; Bone Morphogenetic Protein Receptors, Type II; Case-Control Studies; Caveolin 1; Cell Proliferation; Disease Models, Animal; Endothelial Cells; Extracellular Vesicles; Female; Humans; Hypoxia; Indoles; Male; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Nitric Oxide Synthase Type III; Pulmonary Arterial Hypertension; Pyrroles; Rats, Sprague-Dawley; Signal Transduction; Smad Proteins; Transforming Growth Factor beta; Vascular Remodeling; Young Adult

Pulmonary arterial hypertension (PAH) is characterized by enhanced proliferation of pulmonary artery smooth muscle cells (PASMCs) accompanying increased production of inflammatory factors and adaptation of the mitochondrial metabolism to a hyperproliferative state. However, all the drugs in clinical use target pulmonary vascular dilatation, which may not be effective for patients with advanced PAH.. We aimed to discover a novel drug for PAH that inhibits PASMC proliferation.. We screened 5562 compounds from original library using high-throughput screening system to discover compounds which inhibit proliferation of PASMCs from patients with PAH (PAH-PASMCs). We found that celastramycin, a benzoyl pyrrole-type compound originally found in a bacteria extract, inhibited the proliferation of PAH-PASMCs in a dose-dependent manner with relatively small effects on PASMCs from healthy donors. Then, we made 25 analogs of celastramycin and selected the lead compound, which significantly inhibited cell proliferation of PAH-PASMCs and reduced cytosolic reactive oxygen species levels. Mechanistic analysis demonstrated that celastramycin reduced the protein levels of HIF-1α (hypoxia-inducible factor 1α), which impairs aerobic metabolism, and κB (nuclear factor-κB), which induces proinflammatory signals, in PAH-PASMCs, leading to reduced secretion of inflammatory cytokine. Importantly, celastramycin treatment reduced reactive oxygen species levels in PAH-PASMCs with increased protein levels of Nrf2 (nuclear factor erythroid 2-related factor 2), a master regulator of cellular response against oxidative stress. Furthermore, celastramycin treatment improved mitochondrial energy metabolism with recovered mitochondrial network formation in PAH-PASMCs. Moreover, these celastramycin-mediated effects were regulated by ZFC3H1 (zinc finger C3H1 domain-containing protein), a binding partner of celastramycin. Finally, celastramycin treatment ameliorated pulmonary hypertension in 3 experimental animal models, accompanied by reduced inflammatory changes in the lungs.. These results indicate that celastramycin ameliorates pulmonary hypertension, reducing excessive proliferation of PAH-PASMCs with less inflammation and reactive oxygen species levels, and recovered mitochondrial energy metabolism. Thus, celastramycin is a novel drug for PAH that targets antiproliferative effects on PAH-PASMCs.

Topics: Animals; Cells, Cultured; Cytokines; Disease Models, Animal; Drug Evaluation, Preclinical; Energy Metabolism; High-Throughput Screening Assays; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Indoles; Male; Metabolome; Mice; Mitochondria; Monocrotaline; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Naphthoquinones; NF-E2-Related Factor 2; NF-kappa B; Oxidative Stress; Pulmonary Arterial Hypertension; Pulmonary Artery; Pyrroles; Rats; Reactive Oxygen Species; Resorcinols; Transcription Factors