Relationship between endothelial progenitor cells and cardiovascular diseases in maintenance hemodialysis patients

Abstract

Objective To investigate the relationship between the variation of endothelial progenitor cells (EPC) number and cardiovascular diseases (CVD) in maintenance hemodialysis (MHD) patients, and discuss the function of EPC in the progression of CVD in MHD. Methods One hundred and fifteen MHD patients over 18 years whose dialysis vintage was over six months from Department of Nephrology, Renji Hospital, Shanghai Jiao Tong University School of Medicine were enrolled. They were divided into CVD group and non-CVD group by medical history, electrokardiographie (EKG), cardiac ultrasound, peripheral vascular imaging and cardiovascular imaging. Peripheral blood (5 ml) was collected for detecting EPC number by flow cytometry as CD34/CD133/vascular endothelial growth factor receptor 2 (VEGFR2) cells. The EPC number between CVD group and non-CVD group was compared. The relationship between the decrease of EPC number and CVD risks in MHD patients was analyzed by logistic regression analysis. In a three-year follow-up, the death and new CVD events of the two groups were compared in order to discuss the relationship between EPC number and adverse events. Results Among 115 MHD patients, the average age was 61.57±12.76, male/female was 71/44, the average dialysis vintage was (86.24±56.31) months, the average Kt/V was 1.69±0.29 and average ultrafiltration volume was (2.48±0.90) L. Forty-four patients in 115 (38.3%) were with concurrent CVD. The EPC number in CVD group was significantly lower than that in non CVD group (P=0.015). The CVD group had higher serum phosphate (P=0.013), higher glycosylated hemoglobin (P<0.001), but serum calcium, intact parathyroid hormone (iPTH) and other indicators had no significant difference between two groups. Multiple Logistic regression analysis showed that older age (OR=1.061), history of diabetes (OR=9.796), dialysis vintage (OR=1.015), serum phosphate (OR=3.766), decrease of EPC number (OR=0.909) were the independent impact factors of CVD events in MHD patients. There were 22 patients of the 115 MHD patients had encountered a new CVD event in a three-year follow-up between December 2012 and December 2015, 9 patients from the CVD group and 13 patients from the Non-CVD group, and there was no significant difference between two groups (P=0.776). Nine patients from the CVD group and 7 patients from the Non-CVD group died in the follow-up, and there was no significant difference (P=0.111). Seventy-one MHD patients from the non-CVD group were divided into two groups by the median of EPC number. There were 3 patients in the higher EPC number group encountered CVD events and 10 patients in the lower EPC number group encountered CVD events, which had significant difference (P=0.024). Conclusion The decrease of circulating EPC number may be related with CVD events in MHD patients. Even adjusted by age, sex, diabetes, dialysis vintage and serum phosphate, decreased EPC number is still the independent risk factor of CVD events in MHD patients. The decrease of EPC number in MHD patients may be used to predict the occurrence of cardiovascular events. Key words: Renal dialysis; Cardiovascular diseases; Endothelial progenitor cells; End stage renal disease; Flow cytometry