Angiopoietin-1 improves endothelial progenitor cell-dependent neovascularization in diabetic wounds.

Abstract

BACKGROUND:

The diabetic phenotype of wound healing is in part characterized by impaired neovascularization and deficient endothelial progenitor cell (EPC) recruitment. Angiopoietin-1 (Ang-1) is a potent mobilizer of EPCs from the bone marrow (BM). A suggested mechanism for EPC mobilization from the BM is mediated by matrix metalloproteinase 9 (MMP-9) and stem cell factor (SCF). Taken together, we hypothesized that overexpression of Ang-1 in diabetic wounds will recruit EPCs and improve neovascularization and wound healing.

METHODS:

An endothelial lineage BM-labeled murine model of diabetes was developed to track BM-derived EPCs. FVBN mice were lethally irradiated and then reconstituted with BM from syngeneic Tie2/LacZ donor mice. Diabetes was induced with streptozotocin. Dorsal wounds in BM-transplanted mice were treated with Ad-Ang-1, Ad-GFP, or phosphate-buffered saline. At day 7 after injury, wounds were harvested and analyzed. A similar experiment was conducted in EPC mobilization deficient MMP-9 -/- mice to determine whether the effects of Ang-1 were EPC-dependent.

RESULTS:

Overexpression of Ang-1 resulted in greatly improved re-epithelialization, neovascularization, and EPC recruitment in diabetic BM-transplanted wounds at day 7. Ang-1 treatment resulted in increased serum levels of proMMP-9 and SCF but had no effect on vascular endothelial growth factor levels. According to our FACS results, peripheral blood EPC (CD34(+)/Cd133(+)/Flk1(+)) counts at day 3 after wounding showed impaired EPC mobilization in MMP-9 -/- mice compared with those of wild-type controls. EPC mobilization was rescued by SCF administration, validating this model for EPC-mobilization-deficient mechanistic studies. In MMP-9 -/- mice, Ad-Ang-1 accelerated re-epithelialization in a similar manner, but had no effect on neovascularization.

CONCLUSION:

Our results show that Ang-1 administration results in improved neovascularization which is dependent on EPC recruitment and has direct effects on wound re-epithelialization. These data may represent a novel strategy to correct the phenotype of impaired diabetic neovascularization and may improve diabetic wound healing.

• Authors: Swathi Balaji, Nate Han, Chad Moles, Aimen F Shaaban, Paul L Bollyky, Timothy M Crombleholme, Sundeep G Keswani
• Journal: Surgery (Surgery) Vol. 158 Issue 3 Pg. 846-56 (Sep 2015) ISSN: 1532-7361 [Electronic] United States
• PMID: 26266763 (Publication Type: Evaluation Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 Elsevier Inc. All rights reserved.

Chemical References

• Angiogenesis Inducing Agents
• Angiopoietin-1
• Biomarkers

Topics

• Angiogenesis Inducing Agents (administration & dosage, pharmacology)
• Angiopoietin-1 (administration & dosage, pharmacology)
• Animals
• Biomarkers (metabolism)
• Diabetes Mellitus, Experimental (metabolism, pathology)
• Endothelial Progenitor Cells (drug effects, metabolism)
• Enzyme-Linked Immunosorbent Assay
• Female
• Flow Cytometry
• Mice
• Mice, Knockout
• Neovascularization, Physiologic (drug effects)
• Treatment Outcome
• Wound Healing (drug effects)