Circulating Vascular Progenitor Cells in Patients With Type 1 Diabetes and Microalbuminuria

OBJECTIVE: Patients with type 1 diabetes and microalbuminuria are at increased risk of cardiovascular disease (CVD). Abnormalities in vascular progenitor cells, which participate in vascular repair, may be implicated in this susceptibility. RESEARCH DESIGN AND METHODS: We studied the number and function of vascular progenitor cells in 22 type 1 diabetic patients with history of microalbuminuria (MA(+)) and 22 type 1 diabetic patients without history of microalbuminuria (MA(−)), of similar age, diabetes duration, glycemic control, renal function, and no history of CVD. RESULTS: MA(+) patients had lower circulating CD34(+) and CD34(+)/CD133(+) cell numbers compared with MA(−) patients (P < 0.006). In in vitro functional assays, MA(+) patients had a significantly lower number of colony-forming units and impaired vascular endothelial growth factor (VEGF)-A–mediated tube formation, when compared with MA(−) patients (P < 0.01). CONCLUSIONS: In type 1 diabetic patients with microalbuminuria, a marker of microvascular injury and a risk factor for CVD, circulating vascular progenitor cell number is reduced and function is impaired.