engleski

Paraoxonase/arylesterase in serum of patients with type II Diabetes mellitus

Human paraoxonase (EC 3.1.8.1.) is a high-density lipoprotein associated enzyme that is assumed to protect against the oxidation of lipoproteins. Paraoxonase can destroy active lipids in mildly oxidized LDL and hence may protect against the induction of inflammatory responses in arterial wall cells. The association of coronary artery disease and paraoxonase 1 (PON1) activity was reported in many recent papers. PON1 exhibits two sequence polymorphisms, Arg(192)&#8594; Gln and Met(55) &#8594; Leu. PON1 that may play a role in the development of impaired glucose tolerance and have an impact on the cardiovascular risk in patients with type II diabetes. The aim of this study was to determine whether PON1 activities, paraoxonase phenotypes, and lipid status are altered in type II diabetic patients as compared to healthy population. Patients (N = 175) and control subjects (N = 114) were from the area of Zagreb, Croatia. Paraoxon was used as a substrate for measurement of basal or NaCl-stimulated paraoxonase activity, and phenylacetate for measurement of arylesterase activity. Glucose, cholesterol, triglycerides, and HDL-cholesterol were determined by methods routinely used in clinical biochemical laboratories. Enzyme activities are expressed as micromoles of hydrolysed substrate per min per litre of serum (U/l). Basal and NaCl-stimulated paraoxonase activity, as well as arylesterase activity expressed per serum volume, were significantly higher in type II diabetic patients compared to the controls ; 71 % (P = 0.0012), 68 % (P = 0.0013) and 58 % (P < 0.0001), respectively. The distribution of paraoxonase phenotypes was AA 47 %, 53 % AB + BB and 64 % AA, 36 % AB + BB in types II diabetic patients and controls, respectively. Triglycerides, total cholesterol were higher in type II diabetes, and HDL-cholesterol was lower as compared to the controls. From PON1 phenotype distribution it follows that less antiatherogenic paraoxonase B allele is more frequent in type II diabetes patients. Their lipid status is worse as compared to the controls. This might indicate a greater risk of premature atherosclerosis.

paraoxonase; diabetes; lipids; paraoxonase phenotypes

nije evidentirano