Endocrine Abstracts

Background: Sitagliptin, unlike the some major antihyperglycemic drugs, is not associated with weight gain and has neutral effects on body weight. It is unclear whether sitagliptin treatment alters immune functions and insulin resistance in people with type 2 diabetes. The aim of the present study was to assess the effect of sitagliptin on insulin resistance and immune functions in patients with type 2 diabetes mellitus.

Methods: Twenty type 2 diabetic subjects were randomly assigned to receive sitagliptin (100 mg/day; n=10) or medical nutrition therapy (MNT) (n=10) for 12 weeks. Changes in anthropometric variables, glycemic control, insulin resistance, lipid parameters and immune functions were evaluated at baseline and following 12 weeks of treatment. T lymphocyte subgroups like as CD3, CD4, CD8 and TGF-β1, IL-12 were analyzed to evaluate immune functions.

Results: Significant decreases in body weight and body mass index were observed over the entire study period in MNT treatment group but not in sitagliptin group. HbA1c and postprandial plasma glucose (PPG) levels were decreased in the sitagliptin group compared with baseline values but not statistically significant while they were unchanged in the MNT group. There was a significant decrease c-peptide and insulin resistance (HOMA-IR) in sitagliptin group compared with baseline values but not in MNT group at the end of the 12 weeks. Compared to the MNT group we found a decrease in CD4 lymphocyte count by extension CD4/CD8 ratio in the sitagliptin group though statistically insignificant.

Conclusion: In this study of patients with type 2 diabetes, treatment with sitagliptin was associated with a significant decrease in insulin resistance. The decrease in CD4 lymphocyte count was thought be possibly related to the upper airway tract infection-like side effect described in the literature.