Changes Of Levels Of Proinsulin And True Insulin And Its Clinical Significance In Type 2 Diabetes Mellitus

Diabetes mellitus (DM) is seriously hurting human health because of its high morbidity, disability rate and mortality. Type 2 diabetes mellitus (T2DM) makes up most part of the incidence of DM. Insulin resistance (IR) is important in the pathogenesis of T2DM and a key character of insulin resistance syndrome (IRS) . IRS is a common clinical syndrome, including hypertension, hyperlipidemia, impaired glucose tolerance, obesity and so on. IR is in the center of IRS. Hyperinsulinemia is the stigmata of IRS and DM, but traditional immunoreactive insulin (IRI) is not "true insulin (TI) " , it is consisted of proinsulin_PI and other middle substances.T2DM patients mostly die of macroangiopathy. Plasminogen activator inhibitor-1 (PAI-1) is an independent risk factor of cardiovascular disease (CVD) and plays a key role in the pathogenesis of diabetic vascular disease. In recent years, the relationship between insulin and PAI-1 has attracted attention. The purpose of this experiment is not only to study the changes of PI, TI and the relationship among PL TI and factors ofcardiovascular disease such as BMI, WHR, BP, TG, TC,PAI-l,but also to explore the significances of PI, TI in DM. Materials and Methods73 patients with T2DM came from the First or Second Affiliated Hospital of Zhengzhou University. T2DM was diagnosed according to the criteria of ADA(1997).A11 patients had not taken insulin, thiazolidinediones, metformin in last 3 months. Subjects were excluded if they had primary liver,, renal, heart disease, other endocrinopathies, infection and other diabetic acute complications. The patients with T2DM were divided into two groups, according to the definition of IRS of WHO (1998) and NCEP-ATP 111(2002) :1. DM I group, 36 cases, 16 males and 20 females, mean age was 50 10 years ; 2. DMII group, 37 cases, 19 males and 18 females, mean age was 52+8 years. Normal control (NC) group consisted of 30 cases, 16 males and 14 females, mean age was 50 8 years. They came from the Zhengfei Company of Zhengzhou city and all of them were healthy. The "specimens for study are serum and plasma. Sex, age, height (M), weight (Kg), blood pressure, waist circumference (W) , hip circumference (H) were collected in all subjects. BMI and 1HR were calculated (BMI=Kg/M2, WHR=ff/H) . FPI , FTI and PAI-1 were detected by ELISA. By using SPSS 10.0 software package, comparison among the groups was evaluated by AVONA or nonparametric test ; Correlation between two variances was analyzed by Spearman correlation analysis or Pearson correlation analysis. The significance level was set at P<0. 05. Results1. The levels of Fasting true insulin (FTI) in NC group, DM I group and DM II group were 34. 30 7. 73pmol/L, 52. 24 12. 16 pmol/L, 86. 66 11. 12 pmol/L respectively. The difference between each two groups was significant (P<0. 05) . The levels of Fasting Proinsulin (FPI) in NC group. DM I group and DMII group were 6. 26 1.77 pmol/L, 18. 72 2. 11 pmol/L,29.37 + 3.20 pmol/L respectively. The difference between each two groups was significant (P< 0.05). The ratio of FPI/(FPI+FTI) in NC group, DM I group and DM II group were 0. 15 0.04, 0.25 0.02, 0.27 0.04 respectively . The ratio of FPI/ (FPI+FTI ) in DM I group and DMTJ group were significantly higher in NC group (P<0. 05). The difference between DM I group and DMII group was insignificant (P>O. 05). The levels of PAI-1 in NC group, DM I group and DMII group were 19. 19 5. 59ng/ml, 28. 91 8. 02 ng/ml, 49. 41 4. 59 ng/ml respectively. The difference between each two groups was significant (P<0. 05).2. FPI was found to have a positive correlation with BMI (r=0. 630, P =0.000) ,WHR (r=0.558, P=0.000) ,DBP (r=0.422, P=0. 000) ,SBP (r=0. 675, P=0.000) ,TG (r=0.319, P=0.006) ,TC (r=0. 653, P=0.000) in DM group; FT I was found to have a positive correlation with BMI ( r= 0. 598, P=0. 000) ,WHR Cr=0. 566, P =0.000) ,DBP (r=0. 331, P =0.004) ,SBP(r=0. 591, P=0.000) ,TG (r=0.272, P =0.020) ,TC (r=0. 650, P=0.000) in DM group; FPI was closer related to BMI, WHR, DBP, SBP, TG, TC co...