Pioglitazone treatment stimulates circulating CD34-positive cells in type 2 diabetes patients

Circulating bone marrow derived immature cells, including CD34-positive (CD34+) cells, contribute to maintenance of the vasculature, not only as a pool of endothelial progenitor cells (EPCs), but also as a source of growth/angiogenesis factor. We hypothesized that the thiazolidineone compound pioglitazone could stimulate the circulating CD34+ cells in diabetic patients. Thirty-four patients with type 2 diabetes received 15–30 mg pioglitazone for 24 weeks. The number of circulating CD34+ cells significantly increased at 12 and continued this effect for 24 weeks (1.08 ± 0.39, 1.34 ± 0.34 and 1.32 ± 0.28 cells/μl at 0, 12 and 24 weeks, respectively). The change of CD34+ cell levels (ΔCD34+ cells) between 0 and 12 weeks was significantly correlated with the change of high sensitive C reactive protein levels (Δhs-CRP) and change in adiponectin levels (Δadiponectin) (r = −0.412, r = 0.359, respectively). Our study demonstrated that pioglitazone treatment increased circulating CD34+ cells, suggesting that this effect may at least partly contribute to the anti-atherosclerotic action of pioglitazone.