title: Endothelial nitric oxide synthase inhibition does not alter endothelial progenitor cell colony forming capacity or migratory activity.
abstract: Endothelial nitric oxide synthase (eNOS) activity has been shown to play a pivotal role in the mobilization of endothelial progenitor cells (EPCs) into the circulation from bone marrow. Indeed, in eNOS-deficient mice, exercise-induced EPC mobilization is severely diminished. We determined ex vivo whether circulating EPC colony-forming capacity and migratory activity are influenced by eNOS activity. Peripheral-blood mononuclear cells were isolated from 20 healthy adults and preplated for 2 days, and nonadherent cells were further cultured for 7 days in the presence and absence of N-nitro-L-arginine methyl ester (L-NAME, 300 microM, an eNOS antagonist) to determine EPC colony-forming units. Migratory activity of EPCs, cultured with and without L-NAME (300 microM) was determined by utilizing a modified Boyden chamber. The number of EPC colony-forming units was not significantly different when cultured in the absence or presence of L-NAME (21+/-5 vs 18+/-5). Moreover, eNOS inhibition did not alter EPC migratory activity; mean fluorescence was similar in samples cultured with (983+/-126 RFUs) and without (962+/-105 RFUs) L-NAME. These in vitro results suggest that, in contrast to EPC mobilization from the bone marrow, eNOS does not exert a modulatory influence on the functional capacity of circulating EPCs to either form colonies or migrate.
authors.affiliation: Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado 80309, USA. greta.hoetzer@coloradol.edu
authors.forename: Greta L
authors.initials: GL
authors.lastname: Hoetzer
authors.forename: Heather M
authors.initials: HM
authors.lastname: Irmiger
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Keith
authors.forename: Kimber M
authors.initials: KM
authors.lastname: Westbrook
authors.forename: Christopher A
authors.initials: CA
authors.lastname: DeSouza
mesh_terms: D000328:Adult; D000368:Aged; D001854:Bone Marrow Cells / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects*; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D042783:Endothelial Cells / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008858:Microscopy, Phase-Contrast; D008875:Middle Aged; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors*; D013234:Stem Cells / Q000187:drug effects*
chemical_list: D004791:Enzyme Inhibitors; D052250:Nitric Oxide Synthase Type III; D019331:NG-Nitroarginine Methyl Ester