The Relationship Between RAAS And Apelin Serum Levels In The Metabolic Syndrome Patients

Objective: to study the change of apelin-36 concentration in the patients with metabolic syndrome(MS) and the relationship between the apelin-36 and rennin angiotensin aldosterone system(RAAS).Methods: 265 hospitalized patients were divided into metabolic syndrome(MS) group(n=139) and non-metabolic syndrome(NMS) group(n=126) according to the metabolic syndrome criteria. The venous blood was taken from patients who fasting at least 12 hours and stay in bed for at least 4 hours. The fasting plasma glucose(FPG), Hb A1 c,lipid profile were measured. The level of apelin-36,angiotensin converting enzyme 2(ACE2) and angiotensin II(Ang II) were measured by ELISA. Those metabolism indexes between two groups were compared. Pearson test were used to test the relationship among apelin-36,ACE2,Ang II and other metabolic indexes. The multiple linear stepwise regression were used to analysis apelin-36 independent factors.Results: The level of apelin-36,ACE2 and Ang II in MS group was significantly higher than the NMS group(apelin-36: 1271.46±339.72 VS 1010.11±338.12 ng/l,ACE2:113.73±27.35 VS 98.79±29.3 ng/l,Ang II:111.58±32.23 VS 97.65±30.95 ng/l,all P<0.01). No different of the apelin-36 was found among the patients with 3,4 or 5 metabolic risk factors.so were the the groups wiih 2 or less than 2 risk factors. Pearson test showed that the serum apelin-36 level was positively correlated to waist circumference, triglycerides, FPG, free fatty acid(FFA), very low density lipoprotein cholesterol(VLDL-C), ACE2 and Ang II(r=0.367,0.258,0.243,0.15,0.256,0.305,0.315,all P<0.05) and negative correlation to high-density lipoprotein cholesterol(HDL-C), low density lipoprotein cholesterol(LDL-C)(r=-0.246,-0.186,all P<0.05). The level of Ang II was positively correlated to waist circumference, TG, FPG, VLDL–C, Hb A1 c, ACE2, Apelin-36(r=0.234,0.185,0.195,0.18,0.253,0.494,0.315,all P<0.05),negatively correlated to HDL-C(r=-0.21,P<0.05). The level of ACE2 was positively correlated to waist circumference, TG, FPG, VLDL–C, Hb A1 c, Ang II, apelin–36(r=0.261,0.21,0.157,0.197,0.178,0.494,0.305,all P<0.05)and negatively correlated to HDL-C(r =-0.21,P<0.05). Multivariate step-wise regression showed the independent factors of apelin-36 were waist circumference, serum TG and ACE2.Conclusion: The patients with MS have a higher level of serum apelin-36 than that of NMS patinets. The more risk factors of metabolic syndrome, the increasing the level of apelin-36. The waist circumference, serum TG and ACE2 were independent factors of apelin-36.