Derivation and characterization of endothelial cells from patients with chronic thromboembolic pulmonary hypertension

The scientific poster has been selected for a poster discussion session at the ATS 2018 on Wednesday 23rd of May 2018, San Diego (CA), USA. The work has been presented by Valérie Smolders. The poster summarize the metabolic characterization of endothelial cells derived from patients with CTEPH. Key players of the glycolytic pathway are discussed at the mRNA and protein level and enzyme activity. 

Rationale: Material obtained at pulmonary endarterectomy (PEA) offers the unique opportunity to unravel pathophysiological mechanisms underlying chronic thromboembolic pulmonary hypertension (CTEPH). Enhanced proliferation and an apoptosis-resistant phenotype, that could be involved in vascular changes occurring in CTEPH, might be linked to metabolic dysregulation of CTEPH endothelial cells (CTEPH-EC). The aim of this study was the development of an in vitro model of EC pathology using primary cultures of patient derived EC to assay cell metabolism in CTEPH.

Method: Cells isolated from PEA specimens (N=12) were confirmed as being EC. Cell migration was evaluated using scratch migration assay. Metabolic changes in CTEPH-EC are being studied [JA1] [DS2] using RT-PCR, Western-Blot and colorimetric enzyme activity assays.  Findings in CTEPH-EC were compared with human pulmonary arterial endothelial cells (HPAE).

Results: CTEPH-EC showed endothelial cobblestone morphology accompanied with the expression of endothelial markers, such as CD31, vWF and V-CAD. Migration capacity of CTEPH-EC was lower than HPAE (p<0.0001). Lactate dehydrogenase (LDH) activity in cell pellet was higher in CTEPH-EC than in HPAE (median, 167 mU/mL [IQR, 131-197] vs 125 mU/mL [88-135]). No significant differences in the LDH activity were found in the supernatant of the same cultures. Expression of PFKFB3, LDH and other glycolytic enzymes as well as hexokinase activity was not significantly different between CTEPH-EC and HPAE.

Conclusion: Our results show that CTEPH-EC present a functional impairment compared to control endothelial cells. Similarities with the known metabolic profiles of rapid growing cells, enhanced glycolytic rates and reduced oxidative metabolism, suggest the existence of a Warburg effect in CTEPH-EC based on the enhanced LDH activity compared to controls.

Supported by grants H2020-Marie Skłodowska-Curie ITN (No. 675527), SEPAR (188/2013, 164/2016), SOCAP, FCHP and Fondo de Investigación Sanitaria (PI15/00582).