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.The number of circulating endothelial progenitor cells inversely relates to cardiovascular disease (CVD) (1–3); microalbuminuria is one of the earliest manifestations of diabetic nephropathy and a marker of CVD (4). A subset of patients with type 1 diabetes is susceptible to diabetic nephropathy, a condition characterized by a higher risk of cardiovascular morbidity and mortality (4,5). Type 1 diabetic patients without complications have a lower number of circulating progenitor cells than healthy control subjects (6,7). To gain insight into the susceptibility to CVD in type 1 diabetes, we studied circulating vascular progenitor cell number and function in type 1 diabetic patients with and without microalbuminuria.