Acute and chronic endurance exercise effects on nitric oxide, superoxide, and redox‐related gene expression in circulating CD34+ cells

Abstract

The angiogenic potential of circulating CD34+ progenitor cells depends largely on the balance between intracellular nitric oxide (NO) and superoxide (O2−) levels. Our objective was to determine intracellular NO and O2− levels and expression of redox-related genes [endothelial nitric oxide synthase (eNOS), NADPH oxidase subunits p47phox and gp91phox, and superoxide dismutase-2 (SOD2)] in CD34+ cells isolated before and after acute exercise in age- and BMI-matched endurance-trained (ET) and sedentary (S) men. ET had lower baseline CD34+ cell NO and O2− levels than S (P < 0.05), and baseline eNOS and p47phox mRNA levels were higher in ET than S (P < 0.05). Acute exercise normalized group differences in NO and O2−, and p47phox mRNA decreased significantly in both ET and S (P < 0.05). gp91phox mRNA levels were similar between groups at baseline and decreased in S only (P < 0.05). We observed no differences in SOD2 mRNA levels between groups or with acute exercise. CONCLUSIONS The higher NO and lower p47phox mRNA levels observed in the S group's CD34+ cells were unexpected, as our previous work indicated that exercise enhanced NO dynamics in circulating angiogenic cells. However, given the lower O2− levels and higher eNOS mRNA in the ET group's cells, it appears that exercise training enhances intracellular conditions for vasoprotective angiogenic actions of CD34+ cells.