Endocrine Abstracts

Background: Endothelial progenitor cells (EPCs) play an important role in neovascularization and endothelial regeneration, and the number and function of circulating EPCs is decreased in patients with diabetic retinopathy and type 1 diabetic nephropathy. However, the number and function of EPCs in patients with type 2 diabetes nephropathy is unknown.

Methods: Participants were divided into three groups: 1) type 2 diabetes with overt nephropathy (DN group, n=21), 2) type 2 diabetes without micro-albuminuria (diabetes group, n=19), and healthy controls (n=16). Circulating CD34+/vascular endothelial growth factor receptor 2 (VEGFR2)+ cells were isolated from the peripheral blood and analyzed by flow cytometry. Migration, tube formation, and apoptosis were assessed in EPCs in vitro. bcl-2/bax genes were evaluated by RT-PCR.

Results: The number of EPCs in the DN group was higher than that in the diabetes group, while the numbers of EPCs in both the DN and diabetes groups were lower than that in the control group (8.74±0.24, 6.15±0.30, 19.79±0.35×106/l, P<0.05). However, EPC function was decreased in the DN group (P<0.05) in both migration and tube-forming assays. The rate of apoptosis was highest in the diabetes group and lowest in the control group (18.2%±0.24% vs 6.8%±0.19% respectively). mRNA level of bcl-2/bax was lowest in the diabetes group and highest in the DN group (P<0.05).

Conclusions: In type 2 diabetic nephropathy patients, EPCs’ function was decreased but the number was increased compared with that in diabetes. At the same time, apoptosis of EPC in over DN stage was increased as well as the bax/bcl-2 mRNA level. Our results demonstrated that EPCs were involved in the progression of overt diabetic nephropathy and may be a predictor of disease.