The aim of this study was to investigate the possible relation of microvascular complications of diabetes mellitus and adenosine deaminase (ADA) activity which plays an important role in modulation of insulin action on glucose and lipid metabolism via decreased amounts of tissue adenosine content. Seventy-one (51F/ 20M) patients with type 2 diabetes mellitus and age, gender matched 33 (20F/13M) healthy control subjects were included in the study. All diabetic patients were evaluated for diabetic nephropathy (micro- or macroalbuminuria), retinopathy and serum total ADA activity. Serum total ADA activity of the patients with type 2 diabetes mellitus was 21.1±7.8 U/L and significantly higher than the control group (15.4±2.7U/L) (p<0.001). Serum total ADA activity of the well-controlled patients (HbA1C <7%) was significantly lower than that of the poorly-controlled patients (HbA1C (%7) (15.6±3.7 U/L vs. 22.3±7.8 U/L, p<0.05), but not different from the healthy control group (p>0.05). There was no difference between the ADA activity o f dislipidemic/normolipidemic, hypertensive/normotensive, obese/non-obese, insulin/ OAD treated patients and patients with/without nephropathy and retinopathy (p>0.05). On the basis of this study a significant elevation of serum total ADA activity was observed in poorly-controlled type 2 diabetes mellitus patients. But a relation with chronic complications was not seen. A relation with hyperglycemia, but not with chronic microvascular complications may suggest a contribution of factors other than hyperglycemia in the development of microvascular complications.
Keywords: Adenosine deaminase, type 2 diabetes mellitus, diabetic nephropathy, diabetic retinopathy