Homocysteine theory of arteriosclerosis.

Arteriosclerotic plaques were found in the aorta and arteries of rabbits given homocysteine thiolactone, methionine or homocysteic acid, both parenterally and in a synthetic diet. Animals given large doses of parenteral methionine or homocysteine thiolactone died of pulmonary embolism and pulmonary infarct. Pyridoxine prevented thrombosis and pulmonary embolism but did not prevent arteriosclerotic plaques. These findings and previous work, showing a new matabolic pathway for sulfate ester synthesis from methionine, the somatotrophic activity of homocysteic acid, and control of cellular growth and intercellular matrix synthesis by homocysteine derivatives, suggest a theory to explain aspects of the pathogenesis of arteriosclerosis.