ABSTRACT
HDL has been shown to prevent the oxidative modification of LDL. The antioxidant activity of HDL is believed to reside in its enzymes, particularly paraoxonase [PON]. To investigate serum PON activity in type 2 diabetics and to find out if it has a role in the development of diabetic micro and macrovascular complications, 51 type 2 diabetic patients [Group II] and 15 age and sex matched healthy controls [group I] were included. Diabetic patients were classified into, 15 patients [8 Male, 7 Female] free from any vascular complications [group IIA], 21 patients [12 Male, 9 Female] with diabetic retinopathy [group IIB] and 15 patients [9 Male, 6 Female] with non hemorrhagic cerebrovascular stroke [group IIC]. According to the severity of diabetic retinopathy, [group IIB] were subdivided into 7 patients with back ground changes [group IIB 1], 7 patients with preproliferative changes [group IIB2] and 7 patients with proliferative changes [group IIB3]. Total plasma cholesterol, HDL-C, triglycerides, Apolipoprotein A1 [ApoA1] and serum PON activity were measured in all subjects of the study.Fundus examination by direct ophthalmoscopy with dilated pupils for the diagnosis and grading of diabetic retinopathy. Diabetics with cerebrovacsular strokes were subjected to C.T. scan to confirm non hemorrhagic nature. Serum PON activity was significantly lower in diabetic patients than control [97.2 +/- 23.5, 156.1 +/- 9.33 U/L] respectively, [P<0.01]. Group IIB and C showed significantly lower serum PON activity in comparison to group IIA [84.19 +/- 14.87, 127 +/- 38 U/L] respectively, [P<0.01]. Serum PON activity were significantly lower in group IIB versus group IIC [74.8 +/- 11.3, 98.7 +/- 11.1 U/L] respectively, [P<0.01]. Diabetics with proliferative retinopathy [group IIB3] had the lower most value of serum PON activity in comparison to group IIB 1 and group lIB 2 [60.5 +/- 10.6, 86.6 +/- 12.1 and 77.2 +/- 11.2] respectively P<0.01. In all diabetic patients serum PON activity was significantly positively correlated with plasma HDL-C [P<0.01] and significantly negatively correlated with each of plasma LD-C and total cholesterol [P<0.01] while there were no significant correlation between serum PON activity and plasma ApoA1, triglycerdies nor with the duration of diabetes. We can conclude that serum PON activity has a potential role in the development of diabetic vascular complications that may be helpful in the near future in providing a rational for new therapeutic approach in preventing premature diabetic vascular complications using enzyme activators