Of four groups of chickens, two (groups I and II) were infected with MDV and two were not (groups III and IV). Groups I and III were fed diets low in lipid, and groups II and IV were fed cholesterol-supplemented diets. Striking grossly visible atherosclerotic lesions were seen in large coronary arteries, aortas, and major aortic branches of infected normocholesterolemic and hypercholesterolemic chickens (groups I and II). In contrast, grossly visible atherosclerotic lesions were not seen in uninfected normocholesterolemic chickens (group III), nor in uninfected hypercholesterolemic chickens (group IV). Microscopically, arterial changes in the infected animals were characterized by occlusive fibromuscular intimal thickening which formed fibrous caps overlying areas of atheromatous change. This change closely resembled chronic atherosclerosis in man. These results may have important bearing on our understanding of the etiology and pathogenesis of human arteriosclerosis since there is widespread and persistent infection of human populations with up to five different herpes-viruses.
Studies were performed to determine if cultured human endothelial cells synthesized basement membrane collagen. In culture, endothelial cells were attached to grossly visible membranous structures which on light microscopy were composed of ribbons of dense, amorphous material. On transmission electron microscopy, these membranous structures consisted of amorphous basement membrane, and material morphologically similar to microfibrils and elastic fibers. By immunofluorescence microscopy, these membranous structures stained brightly with antisera to human glomerular basement membrane. Cultured endothelial cells incorporated [3H]proline into protein; 18% of the incorporated [3H]proline was solubilized by purified collagenase. When endothelial cells were cultured with [14C]proline, 7.1% of the incorporated counts were present as [14C]hydroxyproline. Cultured endothelial cells were labeled with [3H]glycine and [3H]proline and digested with pepsin. The resulting fractions on analysis by SDS-polyacrylamide gel electrophoresis contained two radioactive protein peaks of mol wt 94,200 and 120,500. Both these peaks disappeared after digestion with purified collagenase. The peak of mol wt 120,500 corresponds to that of alpha1 (IV) collagen; the peak of the mol wt 94,200 probably corresponds to that of alpha1 (III) collagen. Thus, cultured human endothelial cells synthesize material which is morphologically and immunologically like amorphous basement membrane and biochemically like basement membrane collagen. Cultured endothelial cells probably also synthesize material which is morphologically similar to microfibrils and elastic fibers.