Distribution and composition of acid mucopolysaccharides in normal and atherosclerotic human aortas

The relationship between tissue concentration and composition of the acid mucopolysaccharides (acid MPS) of the human aorta and the stage of atherosclerosis and/or age has been examined. Acid MPS have been analysed in the intima, the media, and excised atherosclerotic lesions from aortas at different stages of atherosclerosis. The analyses comprised the determination of the total acid MPS; the acid MPS that are digestible by testicular hyaluronidase, i.e. hyaluronic acid (HA) plus chondroitin sulphate C (CSA-C); the hyaluronidase-resistant MPS, i.e. heparitin sulphate (HS) plus chondroitin sulphate B (CSA-B), and the four components separately. The concentrations of total acid MPS (per dry defatted weight) vary according to kind of tissue and lesions, but show little correlation with the stage of atherosclerosis. The concentrations of resistant acid MPS are highest in the fatty streaks and spots and lowest in the ulcerated lesions. The concentration of HA decreases with increasing stage of atherosclerosis and/or ageing; that of HS shows a maximum at stage I; that of CSA-C is maximal at II; no correlation was found between CSA-B concentration and stage of the disease. A decreased permeability of the arterial wall and a decreased fibrinolytic activity consequent upon these changes in MPS composition are seen as possible factors in the development of atherosclerotic plaques.