Abstract: 【Abstract】Objective To study the expression and activity of angiotensin II receptor-like 1 endogenous ligand 13 (Apelin-13) and angiotensin Ⅱ (AngⅡ) in autologous arteriovenous fistula (AVF). Methods Ninety patients on hemodialysis were selected and divided into stenosis group (n=45) and normal group (n=45) according to the presence or absence of AVF stenosis. Forty-five patients with chronic kidney disease admitted to the hospital in the same period were selected as the control group. Serum levels of Apelin-13, AngⅡ, and nitric oxide (NO) in the three groups were compared. The correlation between Apelin-13, AngⅡ and NO levels was analyzed in stenosis group. ROC curve was used to analyze the diagnostic value of Apelin-13 and AngⅡ for AVF stenosis. Human umbilical vein endothelial cells (HUVECs) were used to analyze the expression of NO, phosphorylated endothelial nitric oxide synthase (peNOS) and endothelial nitric oxide synthase (eNOS) after stimulation with AngⅡ (group A), Apelin-13 (group B) and AngⅡ combined with Apelin-13 (group C). Results The differences of serum Apelin-13, AngⅡ, and NO levels were statistically significant among steno-sis group, normal group and control group (F=31.125, 64.720 and 21.024 respectively, P= 0.001). In stenosis group, Apelin-13 was positively correlated with NO (r=0.447, P<0.001), and AngⅡ was negatively correlated
with NO (r=-0.611, P<0.001). The AUC of Apelin-13 for the diagnosis of AVF stenosis was 0.780 (95% CI=0.679～0.880), and the AUC of AngⅡ for the diagnosis of AVF stenosis was 0.844 (95% CI=0.760～0.927); no significant difference was found between AUC values of Apelin-13 and AngⅡ for the diagnosis of AVF stenosis (Z=0.959, P=0.337). The differences of NO and peNOS levels were statistically significant among groups A, B and C (F=31.361 and 11.079 respectively, P<0.001). Conclusion Serum Apelin-13 and Ang Ⅱ levels were correlated with NO level in patients with AVF stenosis. Apelin-13 may regulate the eNOS/NO signaling
pathway by antagonizing Ang Ⅱ to inhibit endothelial cell apoptosis, reduce vascular endothelial cell damage and relieve the degree of AVF stenosis in hemodialysis patients.

Key words: Apelin-13, Angiotensin Ⅱ, Autologous arteriovenous fistula stenosis, Nitric oxide