Effect of extra virgin olive oil on experimental thrombosis and primary hemostasis in rats.

BACKGROUND AND AIM: Olive oil is a particular source of fat in the Mediterranean diet, which is associated with a lower incidence of cardiovascular disease. We investigated the possible antithrombotic role of extra virgin olive oil as a single dietary modification in experimental thrombosis and primary hemostasis models in rats. METHODS AND RESULTS: Two different groups of animals were studied: one fed a usual diet (control group) and the other a diet enriched with extra virgin olive oil (3%; weight/weight). After six weeks feeding, arterial thrombosis was initiated by inserting an artificial prosthesis (or "aortic loop") into the aorta, and venous thrombosis was induced by ligating the inferior vena cava. "Template" bleeding time (BT) was measured, as well as factor VII coagulant activity (FVII:C) and fibrinogen levels. The animals fed the olive oil enriched diet showed a significant delay in the thrombotic occlusion of the "aortic loop" (99 +/- 5 h vs 82 +/- 5 h, p < 0.04), a lower incidence of venous thrombosis (57% vs 86%; p < 0.05) and a prolonged BT (154 +/- 7 sec vs 122 +/- 4 sec; p < 0.01) in comparison with the control group. They had lower plasma fibrinogen concentrations (209 +/- 5 mg/dL vs 233 +/- 4 mg/dL; p < 0.01) but similar FVII:C levels (119 +/- 5% vs 108 +/- 5%; p = NS) despite their lower triglyceride concentrations (52 +/- 5 mg/dL vs 79 +/- 10 mg/dL; p < 0.05). CONCLUSIONS: This study provides the first in vivo experimental evidence of the thrombosis prevention properties of olive oil, which are possibly mediated by reduced fibrinogen concentrations and impaired platelet/vessel wall interactions.