Endothelial dysfunction in pulmonary hypertension: cause or consequence?

Pulmonary arterial hypertension (PAH) is a rare, complex, and progressive disease that is characterized by the abnormal remodeling of the pulmonary arteries that leads to right ventricular failure and death. Although our understanding of the causes for abnormal vascular remodeling in PAH is limited, accumulating evidence indicates that endothelial cell (EC) dysfunction is one of the first triggers initiating this process. EC dysfunction leads to the activation of several cellular signalling pathways in the endothelium, resulting in the uncontrolled proliferation of ECs, pulmonary artery smooth muscle cells, and fibroblasts, and eventually leads to vascular remodelling and the occlusion of the pulmonary blood vessels. Other factors that are related to EC dysfunction in PAH are an increase in endothelial to mesenchymal transition, inflammation, apoptosis, and thrombus formation. In this review, we outline the latest advances on the role of EC dysfunction in PAH and other forms of pulmonary hypertension. We also elaborate on the molecular signals that orchestrate EC dysfunction in PAH. Understanding the role and mechanisms of EC dysfunction will unravel the therapeutic potential of targeting this process in PAH.Cardiolog

Differentially Expressed Proteins in Primary Endothelial Cells Derived From Patients With Acute Myocardial Infarction

Endothelial dysfunction is one of the primary factors in the onset and progression of atherothrombosis resulting in acute myocardial infarction (AMI). However, the pathological and cellular mechanisms of endothelial dysfunction in AMI have not been systematically studied. Protein expression profiling in combination with a protein network analysis was used by the mass spectrometry-based label-free quantification approach. This identified and quantified 2246 proteins, of which 335 were differentially regulated in coronary arterial endothelial cells from patients with AMI compared with controls. The differentially regulated protein profiles reveal the alteration of (1) metabolism of RNA, (2) platelet activation, signaling, and aggregation, (3) neutrophil degranulation, (4) metabolism of amino acids and derivatives, (5) cellular responses to stress, and (6) response to elevated platelet cytosolic Ca2+ pathways. Increased production of oxidants and decreased production of antioxidant biomarkers as well as downregulation of proteins with antioxidant properties suggests a role for oxidative stress in mediating endothelial dysfunction during AMI. In conclusion, this is the first quantitative proteomics study to evaluate the cellular mechanisms of endothelial dysfunction in patients with AMI. A better understanding of the endothelial proteome and pathophysiology of AMI may lead to the identification of new drug targets

The inflammatory profile of CTEPH-derived endothelial cells is a possible driver of disease progression

Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension characterized by the presence of fibrotic intraluminal thrombi and causing obliteration of the pulmonary arteries. Although both endothelial cell (EC) dysfunction and inflammation are linked to CTEPH pathogenesis, regulation of the basal inflammatory response of ECs in CTEPH is not fully understood. Therefore, in the present study, we investigated the role of the nuclear factor (NF)-kappa B pro-inflammatory signaling pathway in ECs in CTEPH under basal conditions. Basal mRNA levels of interleukin (IL)-8, IL-1 beta, monocyte chemoattractant protein-1 (MCP-1), C-C motif chemokine ligand 5 (CCL5), and vascular cell adhesion molecule-1 (VCAM-1) were upregulated in CTEPH-ECs compared to the control cells. To assess the involvement of NF-kappa B signaling in basal inflammatory activation, CTEPH-ECs were incubated with the NF-kappa B inhibitor Bay 11-7085. The increase in pro-inflammatory cytokines was abolished when cells were incubated with the NF-kappa B inhibitor. To determine if NF-kappa B was indeed activated, we stained pulmonary endarterectomy (PEA) specimens from CTEPH patients and ECs isolated from PEA specimens for phospho-NF-kappa B-P65 and found that especially the vessels within the thrombus and CTEPH-ECs are positive for phospho-NF-kappa B-P65. In summary, we show that CTEPH-ECs have a pro-inflammatory status under basal conditions, and blocking NF-kappa B signaling reduces the production of inflammatory factors in CTEPH-ECs. Therefore, our results show that the increased basal pro-inflammatory status of CTEPH-ECs is, at least partially, regulated through activation of NF-kappa B signaling and potentially contributes to the pathophysiology and progression of CTEPH.Cardiolog

Clinical physiology and sleep: Insights from the European Respiratory Society Congress 2017

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Dysfunctional endothelial cells in patients with chronic thromboembolic pulmonary hypertension.

Dysfunctional endothelial cells in patients with chronic thromboembolic pulmonary hypertension. Rationale: The material obtained from pulmonary endarterectomy (PEA) offers the unique opportunity to study the pathophysiological mechanisms of chronic thromboembolic pulmonary hypertension (CTEPH) at disease site. Mitochondrial disarrangements in endothelial cells might explain a hyperproliferative resistant phenotype that could explain vascular changes occurring in CTEPH. We aimed to develop an in vitro model of CTEPH using patient-derived cell lines and assess potential mitochondrial disturbances. Methods: Isolated cells from specimens obtained at PEA, were confirmed as being endothelial cells based on cobblestone morphology, endothelial phenotype (flow cytometry, RT-PCR, immunofluorescence) and functional analysis (tubule formation, proliferation and migration). We also measured: i) mitochondrial membrane potential (MMP), mitochondrial content and apoptosis/necrosis by flow cytometry and ii) mitochondrial dynamics (MD) by confocal microscopy. Results: Isolated cells maintained cobblestone morphology and stained positive for endothelial markers. They showed a hyperproliferative phenotype when compared with control human pulmonary artery endothelial cell lines (HPAE): number of Ki67+cells (50.33±13.4 vs 32.5±9.5; p<0.05), and fold expansion (1.56±0.08 vs 0.8±0.05; p<0.002). Functionally, they showed reduced capacity to form tubule structures (150±44 vs 96±21; p<0.03). CEPTH cells tended to show lower rates of depolarized MMP (49.91±14.70 vs. 59.87±8.41, p=NS), a decrease of mitochondrial content (148.94±69.96 vs. 295.57±178.60, PNS) and lower levels of necrosis/apoptosis (23.57±8.03 vs. 29.33±5.94, p=NS). Mitochondria from CTEPH patients tended to be smaller and to show higher circularity (0.45±0.009 vs. 0.43±0.012, p=NS), with less branching (2.77±0.14 vs. 2.93±0.06, p=NS) with respect to controls, both considered as pathologic markers. Conclusions: Endothelial cells obtained from PEA in CTEPH show a hyperproliferative phenotype, impaired function and mitochondrial material derangement, that may play a role in the pathogenesis of pulmonary hypertension after pulmonary embolism

Gene expression profile of angiogenic factors in pulmonary arteries in COPD: Relationship with vascular remodeling

Pulmonary vessel remodeling in chronic obstructive pulmonary disease (COPD) involves changes in smooth muscle cell proliferation, which are highly dependent on the coordinated interaction of angiogenicrelated growth factors. The purpose of the study was to investigate, in isolated pulmonary arteries (PA) from patients with COPD, the gene expression of 46 genes known to be modulators of the angiogenic process and/or involved in smooth muscle cell proliferation and to relate it to vascular remodeling. PA segments were isolated from 29 patients and classified into tertiles, according to intimal thickness. After RNA extraction, the gene expression was assessed by RT-PCR using TaqMan low-density arrays. The univariate analysis only showed upregulation of angiopoietin-2 (ANGPT-2) in remodeled PA (P < 0.05). The immunohistochemical expression of ANGPT-2 correlated with intimal enlargement (r = 0.42, P < 0.05). However, a combination of 10 factors in a multivariate discriminant analysis model explained up to 96% of the classification of the arteries. A network analysis of 46 genes showed major decentralization. In this network, the metalloproteinase-2 (MMP-2) was shown to be the bridge between intimal enlargement and fibrogenic factors. In COPD patients, plasma levels of ANGPT-2 were higher in current smokers or those with pulmonary hypertension. We conclude that an imbalance in ANGPT-2, combined with related factors such as VEGF, β-catenin, and MMP-2, may partially explain the structural derangements of the arterial wall. MMP-2 may act as a bridge channeling actions from the main fibrogenic factors.Fil: Garcia-Lucio, Jessica. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Argemi, Gemma. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Tura Ceide O. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; España. Universidad de Barcelona; EspañaFil: Diez, Marta. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Paul, Tanja. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Bonjoch, Cristina. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Coll-Bonfill, Nuria. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Blanco, Isabel. Universidad de Barcelona; España. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Barberá, Joan A.. Universidad de Barcelona; España. Hospital Clínic-Institut d’Investigacions Biomèdiques August Pi i Sunyer ; EspañaFil: Musri, Melina Mara. Universidad de Barcelona; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Peinado Víctor I.. Universidad de Barcelona; España. Department Of Pulmonary Medicine, Hospital Clinic, Idib; Españ