Effects of concurrent therapy with policosanol and omega-3 fatty acids on lipid profile and platelet aggregation in rabbits.

Background: Policosanol is a mixture of high-molecular-weight aliphatic primary alcohols isolated from sugarcane wax with cholesterol-lowering and antiplatelet effects. Omega-3 fatty acids (FA) from fish oil can protect against coronary disease. An antiarrhythmic mechanism is emerging as the most convincing explanation for omega-3 FA cardiovascular protection, but triglyceride (TG)-lowering effects and inhibition of platelet function could play a role. In view of the effects of policosanol and omega-3 FA on lipid profile and platelet function, potential benefits of combined therapy were expected.

Objective: To investigate whether combined therapy with policosanol and omega-3 FA would offer some benefit, compared with policosanol or omega-3 FA alone, on serum lipid profile and platelet aggregation in rabbits.

Methods: Male rabbits were randomly distributed in four groups (n = 9 per group). A control group received vehicle, one group was treated with policosanol 5 mg/kg and one with omega-3 FA (eicosapentaenoic acid; EPA [47.0%], docosahexaenoic acid; DHEA [41%]) 250 mg/kg, and the fourth received policosanol 5 mg/kg + omega-3 FA 250 mg/kg. Treatments were orally administered for 60 days. Bodyweight, food consumption and animal behaviour were performed at baseline and study completion.

Results: Policosanol significantly lowered low-density lipoprotein cholesterol (LDL-C) [42.7%; p < 0.01] and total cholesterol (TC) [29.4%; p < 0.05], increased high-density lipoprotein (HDL-C) [15.4%; p < 0.05], but left TG levels unchanged. Omega-3 FA significantly lowered TG (47.1%; p < 0.05), but left TC, LDL-C and HDL-C unchanged. Combined therapy decreased LDL-C (38.7%; p < 0.05). Changes in TC, LDL-C and HDL-C obtained with combined therapy were greater (p < 0.05) than those with omega-3 FA, but similar to those with policosanol, whereas the opposite applied to TG reduction. No significant changes in lipid profile were observed in the control group. Policosanol and omega-3 FA significantly (p < 0.05) but moderately inhibited platelet aggregation induced with arachidonic acid (13.3% and 12.4%, respectively); combined therapy achieved greater inhibition (23.9%; p < 0.05). All groups showed similar food consumption and bodyweight gain. No toxic signs were observed in any animal.

Conclusions: Concurrent therapy with policosanol 5 m/kg and omega-3 FA 250 mg/kg lowered LDL-C, TC and TG and increased HDL-C. All treatments inhibited platelet aggregation, but better effects were observed with policosanol + omega-3 FA compared with either treatment alone. Combined therapy was well tolerated. These results suggest that treatment with policosanol + omega-3 FA could be useful for regulating lipid profile and inhibiting platelet aggregation, but conclusive demonstration of such effects requires further experimental and clinical studies.