title: Changes in Adenosine Deaminase Activity in Patients with Type 2 Diabetes Mellitus and Effect of DPP-4 Inhibitor Treatment on ADA Activity.
abstract: BACKGROUND
  Dipeptidyl peptidase 4 (DPP-4, also known as CD26) binds with adenosine deaminase (ADA) to activate T lymphocytes. Here, we investigated whether ADA activity is specifically affected by treatment with DPP-4 inhibitor (DPP4I) compared with other anti-diabetic agents.
  
  
  METHODS
  Fasting ADA activity, in addition to various metabolic and biochemical parameters, were measured in 262 type 2 diabetes mellitus (T2DM) patients taking various anti-diabetic agents and in 46 non-diabetic control subjects.
  
  
  RESULTS
  ADA activity was increased in T2DM patients compared with that in non-diabetic control subjects (mean±standard error, 23.1±0.6 U/L vs. 18.6±0.8 U/L; P<0.05). ADA activity was correlated with fasting plasma glucose (r=0.258, P<0.05), HbA1c (r=0.208, P<0.05), aspartate aminotransferase (r=0.325, P<0.05), and alanine aminotransferase (r=0.248, P<0.05). Compared with the well-controlled T2DM patients (HbA1c<7%), the poorly controlled group (HbA1c>9%) showed significantly increased ADA activity (21.1±0.8 U/L vs. 25.4±1.6 U/L; P<0.05). The effect of DPP4I on ADA activity in T2DM patients did not differ from those of other oral anti-diabetic agents or insulin. T2DM patients on metformin monotherapy showed a lower ADA activity (20.9±1.0 U/L vs. 28.1±2.8 U/L; P<0.05) compared with that of those on sulfonylurea monotherapy.
  
  
  CONCLUSIONS
  Our results show that ADA activity is increased in T2DM patients compared to that in non-diabetic patients, is positively correlated with blood glucose level, and that DPP4I has no additional specific effect on ADA activity, except for a glycemic control- or HbA1c-dependent effect.
authors: Department of Internal Medicine, Jeju National University Hospital, Jeju National University School of Medicine, Jeju, Korea.
authors: Jae-Geun
authors: JG
authors: Lee
authors: Dong Gu
authors: DG
authors: Kang
authors: Jung Re
authors: JR
authors: Yu
authors: Youngree
authors: Y
authors: Kim
authors: Jinsoek
authors: J
authors: Kim
authors: Gwanpyo
authors: G
authors: Koh
authors: Daeho
authors: D
authors: Lee