scholarly journals Pulmonary Vascular Platform Models the Effects of Flow and Pressure on Endothelial Dysfunction in BMPR2 Associated Pulmonary Arterial Hypertension

2018 ◽  
Vol 19 (9) ◽  
pp. 2561 ◽  
Author(s):  
Reid D’Amico ◽  
Shannon Faley ◽  
Ha-na Shim ◽  
Joanna Prosser ◽  
Vineet Agrawal ◽  
...  

Endothelial dysfunction is a known consequence of bone morphogenetic protein type II receptor (BMPR2) mutations seen in pulmonary arterial hypertension (PAH). However, standard 2D cell culture models fail to mimic the mechanical environment seen in the pulmonary vasculature. Hydrogels have emerged as promising platforms for 3D disease modeling due to their tunable physical and biochemical properties. In order to recreate the mechanical stimuli seen in the pulmonary vasculature, we have created a novel 3D hydrogel-based pulmonary vasculature model (“artificial arteriole”) that reproduces the pulsatile flow rates and pressures seen in the human lung. Using this platform, we studied both Bmpr2R899X and WT endothelial cells to better understand how the addition of oscillatory flow and physiological pressure influenced gene expression, cell morphology, and cell permeability. The addition of oscillatory flow and pressure resulted in several gene expression changes in both WT and Bmpr2R899X cells. However, for many pathways with relevance to PAH etiology, Bmpr2R899X cells responded differently when compared to the WT cells. Bmpr2R899X cells were also found not to elongate in the direction of flow, and instead remained stagnant in morphology despite mechanical stimuli. The increased permeability of the Bmpr2R899X layer was successfully reproduced in our artificial arteriole, with the addition of flow and pressure not leading to significant changes in permeability. Our artificial arteriole is the first to model many mechanical properties seen in the lung. Its tunability enables several new opportunities to study the endothelium in pulmonary vascular disease with increased control over environmental parameters.

2016 ◽  
Vol 6 (4) ◽  
pp. 576-585 ◽  
Author(s):  
Kurt W. Prins ◽  
E. Kenneth Weir ◽  
Stephen L. Archer ◽  
Jeremy Markowitz ◽  
Lauren Rose ◽  
...  

Pulmonary pulse wave transit time (pPTT), defined as the time for the systolic pressure pulse wave to travel from the pulmonary valve to the pulmonary veins, has been reported to be reduced in pulmonary arterial hypertension (PAH); however, the underlying mechanism of reduced pPTT is unknown. Here, we investigate the hypothesis that abbreviated pPTT in PAH results from impaired right ventricular–pulmonary artery (RV-PA) coupling. We quantified pPTT using pulsed-wave Doppler ultrasound from 10 healthy age- and sex-matched controls and 36 patients with PAH. pPTT was reduced in patients with PAH compared with controls. Univariate analysis revealed the following significant predictors of reduced pPTT: age, right ventricular fractional area change (RV FAC), tricuspid annular plane excursion (TAPSE), pulmonary arterial pressures (PAP), diastolic pulmonary gradient, transpulmonary gradient, pulmonary vascular resistance, and RV-PA coupling (defined as RV FAC/mean PAP or TAPSE/mean PAP). Although the correlations between pPTT and invasive markers of pulmonary vascular disease were modest, RV FAC ( r = 0.64, P < 0.0001), TAPSE ( r = 0.67, P < 0.0001), and RV-PA coupling (RV FAC/mean PAP: r = 0.72, P < 0.0001; TAPSE/mean PAP: r = 0.74, P < 0.0001) had the strongest relationships with pPTT. On multivariable analysis, only RV FAC, TAPSE, and RV-PA coupling were independent predictors of pPTT. We conclude that shortening of pPTT in patients with PAH results from altered RV-PA coupling, probably occurring as a result of reduced pulmonary arterial compliance. Thus, pPTT allows noninvasive determination of the status of both the pulmonary vasculature and the response of the RV in patients with PAH, thereby allowing monitoring of disease progression and regression.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Sasha Z Prisco ◽  
Lynn Hartweck ◽  
Lauren Rose ◽  
Thenappan Thenappan ◽  
Kurt W Prins

Introduction: Pulmonary arterial hypertension (PAH) is a lethal pulmonary arterial vasculopathy that results in right ventricle dysfunction (RVD). We showed that microtubule-mediated junctophilin-2 (MT-JPH2 pathway) downregulation promotes t-tubule disruption and RVD; however, the upstream regulators of this pathway are unknown. GP130 signaling via its downstream mediator, STAT3 promotes microtubule remodeling in neonatal cardiomyocytes. However, the relationship between GP130 signaling and the MT-JPH2 pathway in RVD are unknown. Methods: Immunoblots of RV extracts were probed for the GP130 and the MT-JPH2 pathways in MCT rats treated with a GP130 antagonist (2 weeks after MCT injection). Quantitative mass spectrometry analyzed the microtubule associated protein (MAP) fraction of RV extracts. Echocardiography and invasive closed-chest right heart catheterization quantified RV function and pulmonary vascular disease. Pulmonary vasculature remodeling was assessed by H&E histology. Finally, the relationship between the GP130 agonist, interleukin (IL)-6, and RVD in PAH patients was examined. Results: GP130 antagonist treatment blunted RV STAT3 activation, normalized the MT-JPH2 pathway, and restored t-tubule architecture. Hierarchical cluster analysis and principal component analysis of 2842 proteins identified using mass spectrometry revealed normalization of the MAP-fraction with GP130 antagonist treatment. These molecular changes manifested as improved RV function, improved RV-pulmonary artery coupling, blunted RV hypertrophy, and improved survival despite no differences in pulmonary vascular disease severity. In PAH patients, higher IL-6 levels were associated with higher N-terminal pro-brain natriuretic peptide and lower RV fractional area change despite no differences in pulmonary vascular disease burden. Conclusions: Small molecular inhibition of GP130 enhances RV function, and improves survival in MCT PAH via modulation of the MT-JPH2 pathway.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kewal Asosingh ◽  
Suzy Comhair ◽  
Lori Mavrakis ◽  
Weiling Xu ◽  
Dean Horton ◽  
...  

AbstractPulmonary arterial hypertension (PAH) is an insidious disease characterized by severe remodeling of the pulmonary vasculature caused in part by pathologic changes of endothelial cell functions. Although heterogeneity of endothelial cells across various vascular beds is well known, the diversity among endothelial cells in the healthy pulmonary vascular bed and the pathologic diversity among pulmonary arterial endothelial cells (PAEC) in PAH is unknown and previously unexplored. Here single-cell RNA sequencing technology was used to decipher the cellular heterogeneity among PAEC in the human pulmonary arteries isolated from explanted lungs from three patients with PAH undergoing lung transplantation and three healthy donor lungs not utilized for transplantation. Datasets of 36,368 PAH individual endothelial cells and 36,086 healthy cells were analyzed using the SeqGeq bioinformatics program. Total population differential gene expression analyses identified 629 differentially expressed genes between PAH and controls. Gene Ontology and Canonical Ingenuity analysis revealed pathways that are known to be involved in pathogenesis, as well as unique new pathways. At the individual cell level, dimensionality reduction followed by density based clustering revealed the presence of eight unique PAEC clusters that were typified by proliferative, angiogenic or quiescent phenotypes. While control and PAH harbored many similar subgroups of endothelial cells, PAH had greater proportions of angiogenic and proliferative subsets. These findings identify that only specific subgroups of PAH PAEC have gene expression different than healthy PAEC, and suggest these subpopulations lead to the pathologic functions leading to remodeling.


2020 ◽  
Vol 4 (S1) ◽  
Author(s):  
Rosaria Barracano ◽  
Heba Nashat ◽  
Andrew Constantine ◽  
Konstantinos Dimopoulos

Abstract Background Eisenmenger syndrome is a multisystem disorder, characterised by a significant cardiac defect, severe pulmonary hypertension and long-standing cyanosis. Despite the availability of pulmonary hypertension therapies and improved supportive care in specialist centres, Eisenmenger patients are still faced with significant morbidity and mortality. Case presentation We describe the case of a 44-year-old woman with Eisenmenger syndrome secondary to a large secundum atrial septal defect. Her pulmonary vascular disease was treated with pulmonary vasodilators, but she experienced a progressive decline in exercise tolerance, increasing atrial arrhythmias, resulting in referral for transplantation. Her condition was complicated by significant recurrent haemoptysis in the context of extremely dilated pulmonary arteries and in-situ thrombosis, which prompted successful heart and lung transplantation. She made a slow recovery but remains well 3 years post-transplant. Conclusions Patients with Eisenmenger syndrome secondary to a pre-tricuspid lesion, such as an atrial septal defect have a natural history that differs to patients with post-tricuspid shunts; the disease tends to present later in life but is more aggressive, prompting early and aggressive medical intervention with pulmonary arterial hypertension therapies. This case illustrates that severe recurrent haemoptysis can be an indication for expediting transplantation in Eisenmenger syndrome patients.


2018 ◽  
Vol 3 (3) ◽  
pp. 242-248 ◽  
Author(s):  
Matthew Moll ◽  
Romy B Christmann ◽  
Yuqing Zhang ◽  
Michael L Whitfield ◽  
Yu Mei Wang ◽  
...  

Objective: Pulmonary arterial hypertension and interstitial lung disease are major causes of mortality in systemic sclerosis. We used a previously identified microarray biomarker to determine whether systemic sclerosis-pulmonary arterial hypertension and systemic sclerosis-interstitial lung disease patients demonstrate distinct gene expression profiles. Methods: Peripheral blood mononuclear cells were collected from healthy controls ( n = 10), systemic sclerosis patients without pulmonary hypertension (systemic sclerosis-no pulmonary arterial hypertension, n = 39), and systemic sclerosis-pulmonary arterial hypertension patients ( n = 21; mean pulmonary arterial pressure ≥25, pulmonary capillary wedge pressure ≤15, and pulmonary vascular resistance ≥3 Wood units) diagnosed by right heart catheterization. Systemic sclerosis-interstitial lung disease patients were defined as those with evidence of fibrosis on chest computed tomography and significant restriction (forced vital capacity <70% predicted, n = 11). Systemic sclerosis-pulmonary arterial hypertension biomarker included 69 genes selected by unbiased statistical screening of three publicly available microarray studies. RNA levels were measured by NanoString Technologies. Gene expression levels that were significantly correlated with pulmonary arterial hypertension (multiple statistical measures) were chosen as inputs into a forward selection logistic regression model. Results: When interstitial lung disease patients were included ( n = 64), four genes (S100P, CD8B1, CCL2, and TIMP1) and male sex predicted pulmonary arterial hypertension with a high level of accuracy (area under the curve = 0.83). Without interstitial lung disease patients ( n = 53), two genes (THBS1 and CD8B1) and male sex predicted pulmonary arterial hypertension with a high level of accuracy (area under the curve = 0.80). When examining systemic sclerosis patients with borderline elevated pulmonary pressures (mean pulmonary arterial pressure = 21–24 mmHg), gene expression changes closely resembled the systemic sclerosis-pulmonary arterial hypertension group, except for THBS1. Conclusion: Systemic sclerosis-pulmonary arterial hypertension and systemic sclerosis-interstitial lung disease have similar but distinct gene expression profiles. Many gene expression changes occur early in the disease course, potentially allowing early detection. THBS1 appears to be an important mediator in the development of pulmonary arterial hypertension-predominant phenotype. Further prospective investigation is warranted.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Samantha Torquato ◽  
Kiyotake Ishikawa ◽  
Jaume Aguerro ◽  
Bradley A Maron ◽  
Joseph Loscalzo ◽  
...  

Elevated levels of norepinephrine (NE) occur in pulmonary arterial hypertension (PAH) and are determined, in part, by the activity of catechol- O -methyltransferase (COMT). COMT degrades catecholamines, is negatively regulated by calcium, and is expressed by pulmonary artery endothelial cells (PAEC). As hyperaldosteronism occurs in PAH and aldosterone (ALDO) influences calcium levels, we hypothesized that ALDO decreases COMT activity to increase NE levels in PAH. Accordingly, human PAEC were treated with ALDO (10 -7 mol/L), a level that is achieved clinically in PAH, for up to 72 h. Compared to vehicle-treated PAEC, ALDO decreased COMT activity by 59.2 ± 6.2% (p<0.01) to increase NE levels in the medium (122.4 ± 11.8 vs. 210.7 ± 15.5 pg/mL/mg protein, p<0.01). This occurred as a result of an ALDO-mediated decrease in COMT protein expression by 52.6 ± 9.3% (p<0.01) as well as an increase in intracellular calcium levels (102.9 ± 21.0 vs. 167.7 ± 17.8 nmol/L, p<0.05) to inhibit activity. These effects were abrogated by coincubation with spironolactone. To determine the in vivo relevance of these findings, COMT was examined in the rat monocrotaline model of PAH with confirmed hyperALDO. COMT was decreased (47.6 ± 10.2 %control, p<0.05) in remodeled pulmonary arterioles with a concomitant increase in lung NE levels (432.8 ± 44.5 vs. 899.7 ± 34.2 pg/mL, p<0.01) compared to control rats. In the porcine pulmonary vein banding model of pulmonary hypertension (PH-pigs) with elevated mean pulmonary artery pressure (15[13-15] vs. 35[27-43], p<0.01) and pulmonary vascular resistance (PVR) index (1.97[1.74-2.28] vs. 5.78[2.61-8.75], p <0.05), ALDO levels were also increased (27.1 ± 5.1 vs. 60.8 ± 10.6 pg/mL, p<0.03) in advance of right heart failure as compared to sham controls. PH-pigs demonstrated a 48.3 ± 9.9% (p<0.02) decrease in pulmonary vascular COMT expression and an increase in NE levels (114.6 ± 20.2 vs. 1,622.6 ± 489.2 pg/mL, p<0.02) that correlated positively with ALDO levels (R 2 =0.58, p<0.02). These findings were confirmed in patients with PAH. Together, these data indicate that there is crosstalk in the pulmonary vasculature between ALDO and the sympathetic nervous system to regulate NE levels in PAH, and thus, have implications for therapeutic interventions.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Chao Xue

Rationale: Pulmonary arterial hypertension (PAH) is a devastating disease in which oxidative stress has been proposed to mediate pathological changes to the pulmonary vasculature such as endothelial cell (EC) apoptosis, endothelial to mesenchymal transition (EndMT), vascular smooth muscle cell (VSMC) proliferation, and inflammation. Our previous study showed that cyclophilin A (CypA) was secreted from EC and VSMC in response to oxidative stress, and much of the secreted CypA was acetylated (AcK-CypA). Furthermore, CypA was increased in the plasma of patients with PAH. Objective: To evaluate the cell- s pecific role of CypA in PAH and compare the relative effects of AcK-CypA and CypA on EC apoptosis, development of an inflammatory EC phenotype and EndMT. Methods and Results: Transgenic overexpression of CypA in EC, but not SMC, caused a PAH phenotype including increased pulmonary artery pressure, α-smooth muscle actin expression in small arteries, and CD45 positive cells in the lungs. Mechanistic analysis using cultured mouse lung microvascular EC showed that CypA and AcK-CypA increased apoptosis measured by caspase 3 cleavage and TUNEL staining. MM284, a specific inhibitor of extracellular CypA, prevented EC apoptosis. In addition, CypA and AcK-CypA promoted an EC inflammatory phenotype assessed by increased VCAM1 and ICAM1 expression, phosphorylation of p65, and degradation of IkB. Furthermore, CypA and AcK-CypA promoted EndMT assayed by change in cell morphology, increased mesenchymal markers and EndMT related transcription factors. At all concentrations, AcK-CypA stimulated greater increases in apoptosis, inflammation and EndMT than CypA. Conclusions: EC-derived CypA (especially AcK-CypA) causes PAH by a presumptive mechanism involving increased EC apoptosis, inflammation and EndMT. Our results suggest that inhibiting extracellular secreted CypA is a novel therapeutic approach for PAH.


2019 ◽  
Vol 28 (02) ◽  
pp. 112-117
Author(s):  
Sanjay Tyagi ◽  
Vishal Batra

AbstractPulmonary arterial hypertension (PAH) is an uncommon disease characterized progressive remodeling of pulmonary vasculature. Although treatment for PAH have improved in last two decades but the outcome remains fatal. Currently, the therapies for PAH target three well-established pathways the nitric oxide (NO) pathway, endothelin receptors, and prostanoids. There are multiple potential targets for development of newer drugs in PAH which requires meticulous research and clinical trials.


2020 ◽  
pp. 1902061
Author(s):  
David Macias ◽  
Stephen Moore ◽  
Alexi Crosby ◽  
Mark Southwood ◽  
Xinlin Du ◽  
...  

Pulmonary Arterial Hypertension (PAH) is a destructive disease of the pulmonary vasculature often leading to right heart failure and death. Current therapeutic intervention strategies only slow disease progression. The role of aberrant HIF2α stability and function in the initiation and development of pulmonary hypertension (PH) has been an area of intense interest for nearly two decades.Here we determine the effect of a novel HIF2α inhibitor (PT2567) on PH disease initiation and progression, using two pre-clinical models of PH. Haemodynamic measurements were performed followed by collection of heart, lung and blood for pathological, gene expression and biochemical analysis. Blood outgrowth endothelial cells from IPAH patients were used to determine the impact of HIF2α-inhibition on endothelial function.Global inhibition of HIF2a reduced pulmonary vascular haemodynamics and pulmonary vascular remodelling in both su5416/hypoxia prevention and intervention models. PT2567 intervention reduced the expression of PH associated target genes in both lung and cardiac tissues and restored plasma nitrite concentration. Treatment of monocrotaline exposed rodents with PT2567 reduced the impact on cardiovascular haemodynamics and promoted a survival advantage. In vitro, loss of HIF2α signalling in human pulmonary arterial endothelial cells suppresses target genes associated with inflammation, and PT2567 reduced the hyper-proliferative phenotype and over-active arginase activity in blood outgrowth endothelial cells from IPAH patients. These data suggest that targeting HIF2α hetero-dimerisation with an orally bioavailable compound could offer a new therapeutic approach for PAH. Future studies are required to determine the role of HIF in the heterogeneous PAH population.


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