engleski

Effect of hemodialysis on HDL-standardized serum paraoxonase activities

Serum paraoxonase activities in relation to HDL-cholesterol concentrations were studied in uremic patients before and after hemodialysis treatment. Paraoxonase is bound to the apoA-1 of HDL, and the presence of paraoxonase in HDL is the major contributor to the antiatherogenicity of this lipoprotein. The blood samples were collected from 69 patients once a month for four months in succession at the Department of Internal Medicine, Nephrology and Dialysis Unit, General Hospital “ Dr. Josip Benčević” , Slavonski Brod. Blood was drawn after an overnight fast immediately before and after the first hemodialysis session of the week. Cuprophane membranes were used on 15 patients, while modified cellulose acetate and cellulose acetate membranes were used on 42 and 12 patients, respectively. Basal and NaCl-stimulated paraoxonase activities were measured with paraoxon as substrate. HDL-cholesterol was determined after selectively precipitating low- and very low-density lipoproteins. Enzyme activities are expressed in international units per liter of serum or per mmol of HDL-cholesterol. Over a period of four months basal and NaCl-stimulated paraoxonase activities remained constant and there were no significant differences before and after hemodialysis. HDL-cholesterol concentrations in each patient also remained constant over that period. However, HDL-cholesterol concentrations immediately after hemodialysis were higher (on average 20%) than before dialysis. Consequently, HDL-standardized paraoxonase activities were lower after than before hemodialysis. As compared to controls (non-diseased population), the median HDL-standardized serum paraoxonase activities obtained after hemodialysis were significantly lower than those of controls.

paraoxonase; HDL; hemodialysis

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