Coronary myointimal lesions in the dogfish shark Scyliorhinus canicula.

Proliferative lesions have been found in the coronary arteries of five specimens of dogfish shark (Scyliorhinus canicula). Three specimens lacked the internal elastic membrane and had a diffuse thickening of the intima obliterating most of the vascular lumen in several intramyocardial branches. Two specimens had intimal nodules in one of the main coronary conal trunks, where breaking and splitting of the internal elastic membrane and fibrosis of the tunica media were observed. These lesions appear similar to those described in salmonid fishes, but are less frequent. Although high concentrations of blood cholesterol and ApoB-containing lipoproteins have been related to the development of coronary lesions in these bony fishes, the dogfish sharks described in this paper showed low serum concentrations of both total cholesterol (0.33 to 1.64 mg per ml) and triglycerides (0.61 to 0.17 mg per ml).