The Level Of Fasting Serum Apelin And The Relationship Of Fasting Serum Apelin And Other Factors In Newly Diagnosed Type 2 Diabetes Patients

ObjectiveApelin was first discovered by the "reverse pharmacology"approach in 1998,it was first identified as an endogenous ligand of the orphan G-protein-coupled receptor (GPCR),APJ,from bovine stomach extracts.In humans apelin has been shown to be widely expressed.Now,roles have been established for the apelin system in increasing cardiac contractility,lowering blood pressure,regulating fluid homeostasis,modulating pituitary hormone release and food intake and regulating immune function.Recent research has shown that,apelin is an adipocytokine who seems to be associated with insulin levels and the occurrence of type 2 diabetes,but its exact physiological role is not clear.The following test selected 29 patients of type 2 diabetes mellitus and 30 objecects who were normal in recepting oral glucose tolerance test to design to compare the variety of serum apelin in above groups.The aim is to analysis the correlation between serum apelin and insulin resistance and to explore the possible mechanism of apelin effect in the diabetes.MethodsThe case group was type 2 diabetes mellitus(the diagnosis standard made by WHO in 1999).The control group was NGT(normal glucose tolerance).Exclusion standards:(1)age less than 30 or older than 70(2)acute stress and infection within one mouth(3) the blood pressure is controlled above 140/90mmHg(4) morbid obesity(BMI＞40kg/m~2)(5) dyslipidemia(LDL-cholesterol＞160mg/dL,triglyce-ride＞200mg/dL)(6) clinical evidence for either cardiovascular or peripheral artery diseases(history of acute myocardial infarction,coronary angioplasty,or bypass surgery,symptoms of angina,dyspnea or claudicatio,and electrocardiographic abnor-mality)(7) rheumatic diseases,renal,hepatic or thyroid dysfunction,concomitant medications(including herbal),regular alcohol or drug consumption,and pregnancy.Assay the serum apelin:To prepare serum samples,whole blood was drawn into a centrifuge tube that contains no anti-coagulant.Let blood clot at room temperature for 120 mins.Promptly centrifuge the clotted blood at 3,000xg for 15 mins at 4℃.Transfer and store serum samples in separate tubes.Date and identify each sample.for longer storage,keep at -70℃.Avoid freeze/thaw cycles.The serum apelin level was assayed by ELISA.Biochenmical indexes:including fasting plasma glucose,blood lipid,insulinInsulin secretion and insulin effectaccording to the typical HOMA model insulin resistance index was calculated.Statistical analysis:All statistical analysis was performed with Windows SPSS 11.5.Continuous datas were presented as mean±SD if there was normally distributed.Variables between the two groups were compared using t-test..The relationship between apelin and other variables was analyzed by simply correlation analysis.The degree of the correlation was analyzed by step regression analysis.Statistical significance was defined as p＜0.05.Resultsl.The clinical datas and biochemical datas of the two groups(1) The gender,SBP,DBP and BMI were similar between the two groups.(p＞0.05).(2)The patients with type 2 diabetes were older than the controls(p＜0.01).(3) FPG,Fins,ln(HOMA-IR),TG,LDL-C levels were higher in patients with type 2 diabetes(p＜0.05).2.Comparision of the fasting serum apelin levels of each groupThe fasting serum apelin level of type 2 diabetes is significantly lower than that of the control group(p＜0.01).3.The correlation between serum apelin level and other variablesIn the simple correlation analysis,apelin is as an independent variable.It shows that apelin is negatively correlated to SBP,DBP,FPG,Fins,ln(HOMA-IR),TG,LDL-C(the value of r is respectively-0.33,-0.44,-0.70,-0.83,-0.84,-0.41,-0.29, P＜0.05 );After age and sex adjustment,apelin is negatively correlated to SBP,DBP, FPG,Fins,ln(HOMA-IR),TG(the value of r is respectively -0.36,-.050,-0.67, -0.83,-0.83,-0.37,P＜0.01).I did not find any relation of apelin with gender,age,BMI,TC,HDL-C(p＞0.05).4.The step regression analysis of serum apelinApelin is as the independent variable and the dependent is all the other variables in the models.It shows that ln(HOMA-IRX Fins,DBP remained significantly related to serum apelin,regression equation:Y=774.954-69.964×ln(HOMA-IR ) -7.277xFins-2.727xDBP.ConclusionThe fasting serum apelin level of type 2 diabetes is significantly lower than that of the control group.The level of serum apelin as a novel adipocytokine is negatively associated with SBP,DBP,FPG,Fins,ln(HOMA-IR),TG,LDL-C.