Serum dipeptidyl peptidase 4 activity in children with type 1 diabetes mellitus

Background: It is poorly understood whether dipeptidyl peptidase 4 (DPP4) activity is altered and how DPP4 contributes to glycemic control in patients with type 1 diabetes mellitus (T1DM). Aim: The aim of this study was to measure serum DPP4 activity and to assess its relationships to metabolic variables in T1DM children. Methods: Serum DPP4 activity was determined using a fluorometric assay in 43 T1DM and 26 control children. Results: Serum DPP4 activity was significantly higher in T1DM children than in controls (3.57 +/- 0.99 vs. 2.67 +/- 0.77 U/mL, p<0.001). In the T1DM children, DPP4 activity was not correlated with HbA(1c), blood glucose, or diabetes duration. A significant negative correlation was found between DPP4 activity and serum adiponectin levels in the T1DM group (r=-0.35, p<0.05). Conclusions: Serum DPP4 activity was increased in the T1DM children, whereas it was not associated with glycemic control. Given the negative correlation between serum DPP4 and adiponectin levels, further investigations are warranted to elucidate the role of DPP4 on insulin sensitivity in T1DM children.