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

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

Functional and metabolic characterization of endothelial cells in chronic thromboembolic pulmonary hypertension

Pulmonary hypertension (PH) is a condition of increased blood pressure within the arteries of the lung (mPAP > 20mmHg) which affects approximately 1% of the global population. Chronic thromboembolic pulmonary hypertension (CTEPH), group 4 PH, is characterized by unresolved pulmonary emboli and pulmonary vascular remodeling of both occluded and non-occluded vessels. The general aim of this thesis was to improve the understanding of CTEPH pathophysiology by focusing on patient endothelial cell (EC) behaviour and function. For this purpose, we isolated ECs from vascular material collected at pulmonary endarterectomy in patients with CTEPH (referred to as CTEPH-EC) and validated them as an in vitro model for studying endothelial pathology in CTEPH. In conclusion, we identified several abnormalities in CTEPH-EC that could play a role in pathological mechanisms driving CTEPH-specific vascular changes. We described alterations in key processes such as angiogenesis and migration, oxidative stress, metabolism and inflammation. Each of these processes may represent targets for novel therapies or biomarkers.</p

Functional and metabolic characterization of endothelial cells in chronic thromboembolic pulmonary hypertension

Pulmonary hypertension (PH) is a condition of increased blood pressure within the arteries of the lung (mPAP > 20mmHg) which affects approximately 1% of the global population. Chronic thromboembolic pulmonary hypertension (CTEPH), group 4 PH, is characterized by unresolved pulmonary emboli and pulmonary vascular remodeling of both occluded and non-occluded vessels. The general aim of this thesis was to improve the understanding of CTEPH pathophysiology by focusing on patient endothelial cell (EC) behaviour and function. For this purpose, we isolated ECs from vascular material collected at pulmonary endarterectomy in patients with CTEPH (referred to as CTEPH-EC) and validated them as an in vitro model for studying endothelial pathology in CTEPH. In conclusion, we identified several abnormalities in CTEPH-EC that could play a role in pathological mechanisms driving CTEPH-specific vascular changes. We described alterations in key processes such as angiogenesis and migration, oxidative stress, metabolism and inflammation. Each of these processes may represent targets for novel therapies or biomarkers.</p

Functional and metabolic characterization of endothelial cells in chronic thromboembolic pulmonary hypertension

Pulmonary hypertension (PH) is a condition of increased blood pressure within the arteries of the lung (mPAP > 20mmHg) which affects approximately 1% of the global population. Chronic thromboembolic pulmonary hypertension (CTEPH), group 4 PH, is characterized by unresolved pulmonary emboli and pulmonary vascular remodeling of both occluded and non-occluded vessels. The general aim of this thesis was to improve the understanding of CTEPH pathophysiology by focusing on patient endothelial cell (EC) behaviour and function. For this purpose, we isolated ECs from vascular material collected at pulmonary endarterectomy in patients with CTEPH (referred to as CTEPH-EC) and validated them as an in vitro model for studying endothelial pathology in CTEPH. In conclusion, we identified several abnormalities in CTEPH-EC that could play a role in pathological mechanisms driving CTEPH-specific vascular changes. We described alterations in key processes such as angiogenesis and migration, oxidative stress, metabolism and inflammation. Each of these processes may represent targets for novel therapies or biomarkers.LUMC / Geneeskund

Decreased Glycolysis as Metabolic Fingerprint of Endothelial Cells in Chronic Thromboembolic Pulmonary Hypertension

Vascular Surger

Metabolic profile in endothelial cells of chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) are two forms of pulmonary hypertension (PH) characterized by obstructive vasculopathy. Endothelial dysfunction along with metabolic changes towards increased glycolysis are important in PAH pathophysiology. Less is known about such abnormalities in endothelial cells (ECs) from CTEPH patients. This study provides a systematic metabolic comparison of ECs derived from CTEPH and PAH patients. Metabolic gene expression was studied using qPCR in cultured CTEPH-EC and PAH-EC. Western blot analyses were done for HK2, LDHA, PDHA1, PDK and G6PD. Basal viability of CTEPH-EC and PAH-EC with the incubation with metabolic inhibitors was measured using colorimetric viability assays. Human pulmonary artery endothelial cells (HPAEC) were used as healthy controls. Whereas PAH-EC showed significant higher mRNA levels of GLUT1, HK2, LDHA, PDHA1 and GLUD1 metabolic enzymes compared to HPAEC, CTEPH-EC did not. Oxidative phosphorylation associated proteins had an increased expression in PAH-EC compared to CTEPH-EC and HPAEC. PAH-EC, CTEPH-EC and HPAEC presented similar HOXD macrovascular gene expression. Metabolic inhibitors showed a dose-dependent reduction in viability in all three groups, predominantly in PAH-EC. A different metabolic profile is present in CTEPH-EC compared to PAH-EC and suggests differences in molecular mechanisms important in the disease pathology and treatment.Vascular Surger

Metabolic profile in endothelial cells of chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) are two forms of pulmonary hypertension (PH) characterized by obstructive vasculopathy. Endothelial dysfunction along with metabolic changes towards increased glycolysis are important in PAH pathophysiology. Less is known about such abnormalities in endothelial cells (ECs) from CTEPH patients. This study provides a systematic metabolic comparison of ECs derived from CTEPH and PAH patients. Metabolic gene expression was studied using qPCR in cultured CTEPH-EC and PAH-EC. Western blot analyses were done for HK2, LDHA, PDHA1, PDK and G6PD. Basal viability of CTEPH-EC and PAH-EC with the incubation with metabolic inhibitors was measured using colorimetric viability assays. Human pulmonary artery endothelial cells (HPAEC) were used as healthy controls. Whereas PAH-EC showed significant higher mRNA levels of GLUT1, HK2, LDHA, PDHA1 and GLUD1 metabolic enzymes compared to HPAEC, CTEPH-EC did not. Oxidative phosphorylation associated proteins had an increased expression in PAH-EC compared to CTEPH-EC and HPAEC. PAH-EC, CTEPH-EC and HPAEC presented similar HOXD macrovascular gene expression. Metabolic inhibitors showed a dose-dependent reduction in viability in all three groups, predominantly in PAH-EC. A different metabolic profile is present in CTEPH-EC compared to PAH-EC and suggests differences in molecular mechanisms important in the disease pathology and treatment

Metabolic profile in endothelial cells of chronic thromboembolic pulmonary hypertension and pulmonary arterial hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) are two forms of pulmonary hypertension (PH) characterized by obstructive vasculopathy. Endothelial dysfunction along with metabolic changes towards increased glycolysis are important in PAH pathophysiology. Less is known about such abnormalities in endothelial cells (ECs) from CTEPH patients. This study provides a systematic metabolic comparison of ECs derived from CTEPH and PAH patients. Metabolic gene expression was studied using qPCR in cultured CTEPH-EC and PAH-EC. Western blot analyses were done for HK2, LDHA, PDHA1, PDK and G6PD. Basal viability of CTEPH-EC and PAH-EC with the incubation with metabolic inhibitors was measured using colorimetric viability assays. Human pulmonary artery endothelial cells (HPAEC) were used as healthy controls. Whereas PAH-EC showed significant higher mRNA levels of GLUT1, HK2, LDHA, PDHA1 and GLUD1 metabolic enzymes compared to HPAEC, CTEPH-EC did not. Oxidative phosphorylation associated proteins had an increased expression in PAH-EC compared to CTEPH-EC and HPAEC. PAH-EC, CTEPH-EC and HPAEC presented similar HOXD macrovascular gene expression. Metabolic inhibitors showed a dose-dependent reduction in viability in all three groups, predominantly in PAH-EC. A different metabolic profile is present in CTEPH-EC compared to PAH-EC and suggests differences in molecular mechanisms important in the disease pathology and treatment