Biochemical variations in electrically induced intimal smooth muscle cell proliferates of the rabbit carotid artery

Common carotid arteries of rabbits were locally stimulated every day by chronically repeated electrical impulses for periods up to 4 weeks. Morphological observations revealed that, primarily at the anodal site of the stimulated segment, smooth muscle cells penetrated from the media through the internal elastic membrane and proliferated in the subendothelial space below a morphologically unchanged endothelium. When the plasma cholesterol was raised by cholesterol feeding, typical atheromatous plaques were formed. Biochemical studies showed an increased metabolic activity of the proliferating cells; in comparison with normal intima-media, the tissue content of DNA, protein, and lactate was increased, whereas that of glucose and glycogen was decreased in the proliferates. Furthermore, during in vitro incubation, the uptake of oxygen and glucose and the production of lactate was enhanced. The increased energy consumption of the proliferates indicates a modified metabolic function of these cells.