Inhibition of NADPH oxidase restores vasoreparative function in diabetic CD34+ cells

Abstract

We have previously showed that inhibition of NADPH oxidase corrected diabetic migratory defect in circulating putative endothelial progenitor cells (CD34+) by decreasing the production of reactive oxygen species (ROS) thereby increasing intracellular nitric oxide (NO). In this study, we evaluated the effect of NADPH oxidase blockade on the vascular engraftment potential of diabetic CD34+ cells. Peripheral blood CD34+ cells were isolated from healthy and Type 1‐diabetic individuals by immunomagnetic selection. Endothelial nitric oxide synthase (eNOS) activity, intracellular NO and cGMP production were quantified. Vascular engraftment potential of CD34+ cells was evaluated in a mouse model of retinal ischemia/reperfusion injury. Activation of eNOS in response to stromal derived factor‐1 (SDF1, 100 nM) was lower in diabetic compared to non‐diabetic cells. Treatment with apocynin or gp91ds‐tat has no effect on eNOS activity but increased intracellular NO levels and cGMP production in response to SDF1. In mouse retinal I/R injury model, vascular incorporation of diabetic CD34+ cells followed by intravitreal injection was significantly lower compared to that with non‐diabetic cells and was significantly increased after ex vivo treatment with apocynin or gp91ds‐tat. These results suggest that ex vivo NADPH oxidase inhibition increases the vascular engraftment potential of diabetic CD34+ cells.