| ObjectiveTo investigate the differences of secretory functions of islet alpha cells in different types of diabetic patients and analyze their relationship with blood glucose fluctuation.MethodsThis observational study recruited 55 type 1 diabetes mellitus(T1DM)patients with insulin therapy and 88 type 2 diabetes mellitus(T2DM)patients without insulin therapy,hospitalized in the endocrinology wards in Nanjing General Hospital.All patients underwent a 100g standard steamed buns meal test,measuring the levels of serum glucose,glucagon,insulin,C-peptide in different points of time;All T2DM patients and 48 of the T1DM patients used continuous glucose monitoring system(CGMS)to monitor blood glucose in three consecutive day.T1DM patients were divided into 3 groups according to the courses of disease,Group 1(the disease duration no more than 1 year)(n=28),Group 2(the disease duration being 1 year to 5 years)(n=11),Group 3(the disease duration more than 5 years)(n=16).T2DM patients were divided into three group according to theHbA1c levels,Group A(HbA1c≤6.5)(n=27),Group B(6.5<HbA1c<8)(n=32),Group C(HbA1c≥8)(n=29).The standard deviation of glucose(SD),Mean amplitude of glycemic excursions(MAGE),Absolute means of daily differences(MODD),Low Blood Glucose Index(LBGI)and Coefficient of variation(CV)were used to evaluate glycemic variability.Results(1)For T1DM patients,the fasting glucagon level in Group 1 was significantly higher than it in Group 2.Furthermore,the GLA1 h,the GLA3h and the AUCGLA0-3h in Group 1 were greatly larger than those in Group 3.Referring to glycemic variability,the LBGI,AUC of hypoglycemia,the percentage of hypoglycemia time and the times of nocturnal hypoglycemia in Group 1 were significantly lower than those in Group 3.Moreover,the fasting glucagon level was negatively correlated with SD and MODD,and it was also the independent factors to SD and MAGE.The AUCGLAO-3h were negatively correlated with MODD,LBGI and AUCnoc-hypogly.What’s more,in 12 type 1 diabetes patients without residual beta-cell function,we also found the fasting glucagon level were negatively correlated with MODD,LBGI and the AUCnoc-hypoglu.(2)For T2DM patients,the three groups showed no difference in these indexes such as gender composition,age,the course of disease,blood lipid and blood pressure.The higher the level of HbAlc,the higher the fasting glucose level,the glucose levels and the GLA/CP at different time points after energy loaded,the AUCGLAO-3h/AUCCP0-3h,SD and MODD,and the lower these indexes such as AUCcpO-3h,HOMA-p,△I30/AG30,the levels of C peptide at different time points after energy loaded.But the fasting C peptide,GLA/CPOh and the glucagon levels at all different time points showed no difference in different groups.Moreover,the glycemic variability indexes(SD,MAGE,MODD)were positively correlated with HbAIC，GLA/CPlh,and negatively with AUCCPO-3h、△I30/△G30.And MBG,MODD were positively correlated with AUCGLA0-3h/AUCcpO-3h.Furthermore,multivariate linear stepwise regression analysis showed GLA/CP1h was an independent factor for MAGE(β=0.071,p=0.031).ConclusionOur findings show that islet a cell secretory functions impair with duration of type 1 diabetes extended and correlate to glycemic fluctuation,especially hypoglycemia and long term poor blood glucose control in T2DM patients impairs the function of islet a and β cells,which will affect the glycemic fluctuation. |
