Variations in Rabbit Aortic Endothelial and Medial Histamine Synthesis in Pre- and Early Experimental Atherosclerosis

The histamine-forming capacity (HFC) of aortic endothelium and medial tissue has been examined in rabbits fed 0.5% cholesterol for 2- and 4-week periods, thereby producing both a preatherosclerotic and histologically identifiable early stage of atherosclerosis. With respect to the HFC of endothelium isolated from aortas of control animals, that of cells isolated from aortas following the 2-week feeding period is essentially double, while no difference exists between the HFC of aortic endothelium from control animals and that of the 4-week dietary group. The medial HFC is similar in all groups. These data thus suggest that one preatherosclerotic metabolic change is an increase in the capacity of endothelial cells to form histamine, and that such a process may occupy a role in increased aortic permeability, an essential component of the atherogenic process.