Aspirin but not meloxicam attenuates early atherosclerosis in apolipoprotein E knockout mice

Atherosclerosis is a complex vascular inflammatory disease. In the last decade it was suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) and in particular inhibition of cyclooxygenase (COX)-2 are associated with an increase in cardiovascular morbidity and mortality. Aspirin is known to reduce the incidence and mortality from ischemic heart disease and is a mainstay in the prevention of vascular complications of atherosclerosis.

To examine the effect of meloxicam, a selective COX-2 inhibitor, or low dose aspirin on the development of experimental atherosclerosis in apoE knockout (KO) compared to wild-type (WT) mice. We aimed to test the hypothesis that meloxicam, a potential vasculitis inducer, would exacerbate atherosclerotic lesions while aspirin, which is known to reduce the incidence of thrombosis occlusive events, would increase protection in this model.

We randomly divided 36 male apoE KO and 36 WT mice, 8 weeks old. Mice were treated for 10 weeks with 0.1 mg/ml aspirin, or 0.05 mg/ml meloxicam, dissolved in their drinking water. Control groups received regular drinking water. At sacrifice, the hearts were removed for histochemical staining and plaque size and composition were examined.

Aspirin-treated animals displayed a decreased atherosclerotic lesion area compared to the untreated control mice, while meloxicam had a null effect on the extent of atherosclerosis in Apo E KO mice.

These results suggest that low dose aspirin reduces early atherosclerosis, while inhibition of COX-2 by meloxicam is not associated with an increase in atherosclerotic plaque size in this mouse model.