title: Treprostinil indirectly regulates endothelial colony forming cell angiogenic properties by increasing VEGF-A produced by mesenchymal stem cells.
abstract: Pulmonary vasodilators and prostacyclin therapy in particular, have markedly improved the outcome of patients with pulmonary hypertension (PH). Endothelial dysfunction is a key feature of PH, and we previously reported that treprostinil therapy increases number and proliferative potential of endothelial colony forming cells (ECFC) isolated from PH patients' blood. In the present study, the objective was to determine how treprostinil contributes to the proangiogenic functions of ECFC. We examined the effect of treprostinil on ECFC obtained from cord blood in terms of colony numbers, proliferative and clonogenic properties in vitro, as well as in vivo vasculogenic properties. Surprisingly, treprostinil inhibited viability of cultured ECFC but did not modify their clonogenic properties or the endothelial differentiation potential from cord blood stem cells. Treprostinil treatment significantly increased the vessel-forming ability of ECFC combined with mesenchymal stem cells (MSC) in Matrigel implanted in nude mice. In vitro, ECFC proliferation was stimulated by conditioned media from treprostinil-pretreated MSC, and this effect was inhibited either by the use of VEGF-A blocking antibodies or siRNA VEGF-A in MSC. Silencing VEGF-A gene in MSC also blocked the pro-angiogenic effect of treprostinil in vivo. In conclusion, increased VEGF-A produced by MSC can account for the increased vessel formation observed during treprostinil treatment. The clinical relevance of these data was confirmed by the high level of VEGF-A detected in plasma from patients with paediatric PH who had been treated with treprostinil. Moreover, our results suggest that VEGF-A level in patients could be a surrogate biomarker of treprostinil efficacy.
authors.affiliation: Prof. David Smadja, Georges Pompidou European Hospital, Hematology Department, 20 rue Leblanc, 75015 Paris, France, Tel.: +31 56093933, Fax: +31 56093393, E-mail: david.smadja@egp.aphp.fr.
authors.forename: David M
authors.initials: DM
authors.lastname: Smadja
authors.forename: Marilyne
authors.initials: M
authors.lastname: Levy
authors.forename: Lan
authors.initials: L
authors.lastname: Huang
authors.forename: Elisa
authors.initials: E
authors.lastname: Rossi
authors.forename: Adeline
authors.initials: A
authors.lastname: Blandinières
authors.forename: Dominique
authors.initials: D
authors.lastname: Israel-Biet
authors.forename: Pascale
authors.initials: P
authors.lastname: Gaussem
authors.forename: Joyce
authors.initials: J
authors.lastname: Bischoff
mesh_terms: D000293:Adolescent; D000328:Adult; D043925:Angiogenesis Inducing Agents / Q000494:pharmacology*; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000959:Antihypertensive Agents / Q000494:pharmacology*; D015415:Biomarkers / Q000097:blood; D002454:Cell Differentiation / Q000187:drug effects; D019070:Cell Lineage; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D066026:Endothelial Progenitor Cells / Q000187:drug effects* / Q000378:metabolism / Q000637:transplantation; D011464:Epoprostenol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D007223:Infant; D008297:Male; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000378:metabolism; D008819:Mice, Nude; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019899:Paracrine Communication / Q000187:drug effects*; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
chemical_list: D043925:Angiogenesis Inducing Agents; D000906:Antibodies; D000959:Antihypertensive Agents; D015415:Biomarkers; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D011464:Epoprostenol; C427248:treprostinil
keywords: Stem cells; endothelial progenitor cells; prostacyclin analogues; vascular remodelling; vasculogenesis