The Changes Of Islet Alpha-and Beta-cell Functions In Elderly Patients With Type2Diabetes Mellitus

Objective: To study the characteristics of insulin resistance and thechanges in function of islet-and-cells in elderly patients with type2diabetes mellitus (T2DM).Methods：One hundred and fifty-five subjects older than60years wererandomly selected from outpatients in Sichuan Provincial People’s Hospitalduring the period from September,2012to February2013. Of these patients,37had normal glucose tolerance (NGT aged group)，38suffered impairedglucose regulation (IGR aged group)，45patients were newly diagnosed astype2diabetes mellitus (new diagnosed diabetes aged group)，and35T2DMpatients had the diseases more than5years (DM with long course aged group).The DM and IGR were defined according to criteria set by World HealthOrganization（WHO）in1999. In addition,33healthy subjects aged25-45years old were used as NGT youth group. Homeostasis modelassessment-insulin resistance index (HOMA-IR) which calculated bymeasuring fasting plasma glucose (FPG) and serum insulin (FNS) wasapplied to assess the status of insulin resistance. HOMA-β was used toassess the basic function of islet β-cells. Serum glucagon was used to assessthe basic function of islet-cells. These indexes in the various aged groupswere compared with33healthy subjects aged20-45years old (NGT youthgroup).Results：1).Compared with the NGT youth group，the levels of FPG,FNS and HOMA-IR and serum glucagon were significantly increased while the level of HOMA-β was decreased in the IGR aged group, new diagnoseddiabetes aged group and DM with long course aged group (all P <005).However, the levels of FPG, FNS, HOMA-IR and serum glucagon in the NGTaged group were not significantly different from that in the NGT youth group.2) The level of FPG, FNS, HOMA-IR and serum glucagon were significantlyhigher while the level of HOMA-β was significantly lower in the IGR agedgroup, new diagnosed diabetes aged group and DM with long course agedgroup than that in the NGT aged group (all P <005).3).The levels of serumglucagon and HOMA-β were also statistically significant difference amongthe IGR aged group, new diagnosed diabetes aged group and DM with longcourse aged group (all P <005).Conclusions: There are insulin resistance and islet cell dysfunction inthe elderly patients with type2DM. The islet cell dysfunction maygradually aggravate compared with the youth group. With the development ofthe disease, although the function of both islet and β-cell could be declined,the failure rate and degree of the β-cell function may be faster and moreserious and than that of the-cell function. In contract, function of islet-cell may be enhanced at the early phase of DM, and hence the failure ofislet-cell function is relatively less than that of β-cell function.