Regression of advanced atherosclerosis in swine: chemical studies

Advanced complicated atherosclerosis was produced in the abdominal aortas of swine by a combination of mechanical injury and of a four-month high-cholesterol, high-fat diet. After discontinuation of the atherogenic diet, the animals were given swine mash for 14 months; subsequent chemical studies showed that regression of lesions had occurred, as delineated by decreased levels of DNA and DNA synthesis, total and esterified cholesterol, and phospholipid but no change in the levels of free cholesterol and triglycerides. The rate of DNA synthesis, but not that of total protein synthesis, had decreased. Collagen content had increased. By all criteria studied, the regressed lesions did not differ greatly from the abdominal aortic tissue of animals that had received only a mash diet for 18 months after mechanical injury. These findings, if extrapolated to man, would make the prognosis for possible regression of atherosclerosis under strictly controlled dietary regimens excellent.