Effects of simvastatin on serum paraoxonase activity

Background: High density lipoprotein (HDL)-associated paraoxonase activity may play an important role in the inhibition of low density lipoprotein (LD L) oxidation. Previous studies have demonstrated that serum paraoxonase act ivity is decreased in patients with hyperlipoproteinaemia and coronary hear t disease, and a few investigators have suggested that the lipid-lowering s tatins may increase paraoxonase levels. Objective: To examine the effect of short-term treatment with simvastatin o n lipids and paraoxonase activity in patients with hyperlipoproteinaemia. Design: Prospective nonblind single-group sequential study. Patients: 112 (52 male and 60 female) hyperlipoproteinaemic patients with F redrickson type IIa and IIb hyperlipoproteinaemia (mean age 52.15 +/- 7.99 years, mean body mass index 27.53 +/- 4.30 kg/m(2)). Methods: Serum cholesterol, lipoproteins, triglycerides, apolipoproteins an d liver function were measured, and serum paraoxonase activity was determin ed spectrophotometrically using paraoxon as substrate. Simvastatin 20 mg/da y was administered for 1 month, and measurements were repeated. Results: Simvastatin significantly decreased serum cholesterol [from 10.25 +/- 2.73 (SD) to 8.85 +/- 2.02 mmol/L], triglyceride (from 3.95 +/- 2.51 to 3.15 +/- 1.47 mmol/L), LDL (from 6.36 +/- 1.70 to 4.94 +/- 1.48 mmol/L.) a nd apolipoprotein B 100 (from 1.93 +/- 0.41 to 1.56 +/- 0.35 g/L) levels, w hereas HDL and apo A I levels did not change significantly (from 1.19 +/- 0 .34 to 1.22 +/- 0.39 mmol/L, and from 1.56 +/- 1.99 to 1.64 +/- 0.24 g/L, r espectively). HDL-associated paraoxonase activity did not change significan tly (from 182.25 +/- 37.21 to 166.49 +/- 35.01 U/L) after simvastatin thera py. Conclusion: Short-term administration of simvastatin did not increase the a ctivity of the HDL-associated antioxidant enzyme paraoxonase.