Objective: A natural anticoagulant Protein C and its cofactor free Protein S, play an important role in the development of thrombosis in diabetics. In this study, we compared Protein C and Protein S concentrations in type 2 diabetic patients and healthy controls and observed their changes between well and poor controlled diabetics.

Method: 30 diabetic patients (age mean 58.66±7.42 years) consisted of 18 women and 12 men and 20 healthy controls (age mean 55.05±5.28 years) consisted of 13 women and 7 men. Patient group was subdivided according to their HbA1c levels as well controlled (HbA1c²%8.0), (n=29) and poor controlled (HbA1c>8.0%), (n=11) diabetics. Protein C and free Protein S, glucose, microalbumin/creatinine and HbA1c concentrations of all individuals were determined. Percent activities of Protein C and free Protein S were determined by use of IL-test commercial kits on ACL Futura analyser (Instrumantation Lab, Milena, Italy). Non-parametric Mann-Whitney U and Spearman correlation tests were used in statistical calculations.

Results: Patient and control groups' Protein C activities were found 94.54%±16.4 and 119.23%±14.31 (p<0.0001), and free Protein S activities as 91.82%±13.72 and 101.26%±12.82 (p=0.028), respectively. Glucose, microalbumin/creatinine, HbA1c concentrations of 2 groups differed significantly from each other (p's<0.0001). In patient group, Protein C activities were inversely and weakly correlated with fasting plasma glucose (r=-0.208) and HbA1c (r=0.246), (p's<0.01) concentrations. Well controlled diabetic group's Protein C activities were (mean±SD) 109.35%±17.62, free Protein S activities were 96.60%±14.39; poor controlled diabetics' Protein C activities were 87.76%±17.04 and free Protein S activities were 91.98%±11.84. Protein C activities significantly differed between 2 groups (p=0.0019), free Protein S activities didnot show a significant difference (p=0.29).

Conclusion: In this study we found serum Protein C and free Protein S activities were significantly lower in type 2 diabetics than in healthy controls and concluded that they may be efficient in the pathogenesis of diabetes mellitus.