Effect of 2-amino-9H-pyrido[2,3-b]indole (AαC), a carcinogenic heterocyclic amine present in food, on atherosclerotic plaque development in apoE deficient mice

There is experimental and epidemiological evidence demonstrating that polycyclic aromatic hydrocarbons (PAHs) are involved in the pathogenesis of cardiovascular diseases. However, heterocyclic amines (HAs), a class of carcinogenic compounds present in food, which share many biochemical features with PAHs, have not received much attention. Previous reports have shown that the heterocyclic amine 2-amino-9H-pyrido[2,3-b]indole (AαC) binds and metabolically affects endothelial cells in animal models suggesting a potential role in vascular remodeling. The present study investigates the effect of exposure to HAs on atherosclerotic plaque development in the apoE−/− mice. We observed that animals treated with AαC developed atherosclerotic lesions characterized by lower lipid content but richer in inflammatory cells and collagen content when compared with control animals. Moreover, atherosclerotic plaques from AαC-treated apoE−/− mice were also smaller with a marked reduction in the tunica media thickness. Furthermore, total cholesterol levels were significantly reduced in AαC-treated apoE−/− mice. In contrast to what has been previously reported for PAHs, we provide for the first time evidence that HAs may protect against cardiovascular disease by inducing stable atherosclerotic plaques and reducing circulating cholesterol levels. These results open new avenues to further investigate the role of these food-borne carcinogens in cardiovascular physiology and pathology.