Diabetic impairments in NO-mediated endothelial progenitor cell mobilization and homing are reversed by hyperoxia and SDF-1α
Katherine A. Gallagher, … , Stephen R. Thom, Omaida C. Velazquez
Katherine A. Gallagher, … , Stephen R. Thom, Omaida C. Velazquez
Published May 1, 2007
Citation Information: J Clin Invest. 2007;117(5):1249-1259. https://doi.org/10.1172/JCI29710.
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Research Article

Diabetic impairments in NO-mediated endothelial progenitor cell mobilization and homing are reversed by hyperoxia and SDF-1α

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–1α (SDF-1α), a chemokine that mediates EPC recruitment in ischemia. Diabetic mice showed impaired phosphorylation of BM eNOS, decreased circulating EPCs, and diminished SDF-1α 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-1α 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-1α 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

Katherine A. Gallagher, Zhao-Jun Liu, Min Xiao, Haiying Chen, Lee J. Goldstein, Donald G. Buerk, April Nedeau, Stephen R. Thom, Omaida C. Velazquez

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Figure 5

Impaired EPC homing to wound tissue in diabetes is reversed by cutaneous administration of SDF-1α.

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Impaired EPC homing to wound tissue in diabetes is reversed by cutaneous...
BM cells from GFP mice were transplanted into γ-irradiated FVB mice. Four groups of wounded diabetic chimeric mice were treated with daily wound injections of PBS, HBO, SDF-1α, or HBO+SDF-1α. After 3 days of treatment, wounds were harvested and analyzed by fluorescent immunostaining of tissue sections with anti–GFP-FITC or anti–VEGFR2-PE Abs. Nuclei were counterstained with Hoescht dye. Recruited EPCs were identified as GFP+/VEGFR2+ cells. (A) Quantification of recruited EPCs in diabetic mice. For each animal, 10 random high-power fields (HPFs, ×100) from 5 serial cross-sections were analyzed, and GFP+/VEGFR2+ cells were quantified relative to the total wound cellularity. Data are based on 3 experiments. SDF-1α+HBO–treated mice had a significant increase in the amount of recruited EPCs compared with other groups (*P < 0.05). SDF-1α–treated animals had a significant increase in amount of tissue EPCs compared with PBS control (**P < 0.05). HBO did not significantly enhance EPC homing to wounds. (B) Representative fluorescent immunostaining of wound sections are shown.