title: Diabetic impairments in NO-mediated endothelial progenitor cell mobilization and homing are reversed by hyperoxia and SDF-1 alpha.
abstract: Endothelial progenitor cells (EPCs) are essential in vasculogenesis and wound healing, but their circulating and wound level numbers are decreased in diabetes. This study aimed to determine mechanisms responsible for the diabetic defect in circulating and wound EPCs. Since mobilization of BM EPCs occurs via eNOS activation, we hypothesized that eNOS activation is impaired in diabetes, which results in reduced EPC mobilization. Since hyperoxia activates NOS in other tissues, we investigated whether hyperoxia restores EPC mobilization in diabetic mice through BM NOS activation. Additionally, we studied the hypothesis that impaired EPC homing in diabetes is due to decreased wound level stromal cell-derived factor-1alpha (SDF-1alpha), a chemokine that mediates EPC recruitment in ischemia. Diabetic mice showed impaired phosphorylation of BM eNOS, decreased circulating EPCs, and diminished SDF-1alpha expression in cutaneous wounds. Hyperoxia increased BM NO and circulating EPCs, effects inhibited by the NOS inhibitor N-nitro-L-arginine-methyl ester. Administration of SDF-1alpha into wounds reversed the EPC homing impairment and, with hyperoxia, synergistically enhanced EPC mobilization, homing, and wound healing. Thus, hyperoxia reversed the diabetic defect in EPC mobilization, and SDF-1alpha reversed the diabetic defect in EPC homing. The targets identified, which we believe to be novel, can significantly advance the field of diabetic wound healing.
authors.affiliation: Department of Surgery, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Gallagher
authors.forename: Zhao-Jun
authors.initials: ZJ
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Xiao
authors.forename: Haiying
authors.initials: H
authors.lastname: Chen
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Goldstein
authors.forename: Donald G
authors.initials: DG
authors.lastname: Buerk
authors.forename: April
authors.initials: A
authors.lastname: Nedeau
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Thom
authors.forename: Omaida C
authors.initials: OC
authors.lastname: Velazquez
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000235:genetics; D002478:Cells, Cultured; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000502:physiology*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology; D018496:Hyperoxia / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000502:physiology*; D010766:Phosphorylation; D013234:Stem Cells / Q000378:metabolism* / Q000473:pathology; D014945:Wound Healing / Q000235:genetics
chemical_list: D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D009569:Nitric Oxide