Higher Serum Dipeptidyl Peptidase-4 Activity in Newly Diagnosed Young-Onset Type 2 Diabetes Mellitus

Background Dipeptidyl peptidase-4 (DPP4) enzyme inhibition is a therapeutic modality for type 2 diabetes mellitus (T2DM). However, its activity is insufficiently explored yet in youth-onset T2DM. Objective The objective of this study is to measure serum DPP4 enzyme activities in youth-onset T2DM and compare them with those in patients with normal glucose tolerance (NGT). Methods This cross-sectional study comprised 29 young participants with newly diagnosed untreated T2DM (age 24.5±4.5 years, range 13-30 years, 51.7% female) and an equal number of young participants with NGT (age 26.5±2.9 years, 48.3% female) screened by a two-sample 75gm oral glucose tolerance test. The relevant history of each participant was obtained, and the waist circumference, waist-hip ratio, blood pressure, and body mass index (BMI) were measured according to the standard procedure and recorded in the data collection sheet. Plasma glucose was measured using the glucose oxidase method, and serum DPP4 activity was measured using the colorimetry method. Results Participants with DM exhibited significantly higher serum DPP4 activity than NGT (DM vs. NGT: 481.4±70.4 pmol/min. vs. 420.3±49.2 pmol/min, mean±SD; p<0.001). A multivariate linear regression model adjusted for age, sex, BMI, and hypertension, found DM as an independent predictor for DPP4 activity (β=0.63.5, 95% CI 28.7-98.4, p=0.022). Conclusion DPP4 activity was significantly elevated in young participants with newly diagnosed T2DM. There might be a pathophysiological implication of DPP4 activity in young-onset T2DM.