Increased Circulating Endothelial Apoptotic Microparticle to Endothelial Progenitor Cell Ratio Is Associated with Subsequent Decline in Glomerular Filtration Rate in Hypertensive Patients

BACKGROUND Recent research indicates hypertensive patients with microalbuminuria have decreased endothelial progenitor cells (EPCs) and increased levels of endothelial apoptotic microparticles (EMP). However, whether these changes are related to a subsequent decline in glomerular filtration rate (GFR) remains unclear. METHODS AND RESULTS We enrolled totally 100 hypertensive out-patients with eGFR ≥ 30 mL/min/1.73 m(2). The mean annual rate of GFR decline (△GFR/y) was -1.49 ± 3.26 mL/min/1.73 m(2) per year during the follow-up period (34 ± 6 months). Flow cytometry was used to assess circulating EPC (CD34(+)/KDR(+)) and EMP levels (CD31(+)/annexin V(+)) in peripheral blood. The △GFR/y was correlated with the EMP to EPC ratio (r= -0.465, p<0.001), microalbuminuria (r= -0.329, p=0.001), and the Framingham risk score (r= -0.245, p=0.013). When we divided the patients into 4 groups according to the EMP to EPC ratio, there was an association between the EMP to EPC ratio and the ΔGFR/y (mean ΔGFR/y: 0.08 ± 3.04 vs. -0.50 ± 2.84 vs. -1.25 ± 2.49 vs. -4.42 ± 2.82, p<0.001). Multivariate analysis indicated that increased EMP to EPC ratio is an independent predictor of ΔeGFR/y. CONCLUSIONS An increased circulating EMP to EPC ratio is associated with subsequent decline in GFR in hypertensive patients, which suggests endothelial damage with reduced vascular repair capacity may contribute to further deterioration of renal function in patients with hypertension.