Skin Diseases Caused by Disorders in Mucopolysaccharide Metabolism

Abstract

The mesenchymal ground substance is an amorphous material that constitutes the matrix of the dermal and subcutaneous connective tissue, together with collagen and elastic fibers. This ground substance contains substantial amounts of glycosaminoglycans, which are rich in acid mucopolysaccharides as well as water, salts, and glycoproteins. The mucopolysaccharide part constitutes about 0.5–1.0 mg per gram dry weight in the skin. The acid mucopolysaccharides are mainly hyaluronic acid, dermatan sulfate, and chondroitin-6-sulfate, as well as smaller amounts of heparitin sulfate. The exact composition of the acid mucopolysaccharides in the skin varies from one region to another and also with age and sex. Wharton’s substance in the umbilical cord contains a preponderance of hyaluronic acid and relatively little sulfated mucopolysaccharides, whereas the skin in an adult contains little hyaluronic acid but more sulfated acid mucopolysaccharides of the type of dermatan sulfate and chondroitin-6-sulfate. The acid mucopolysaccharides in the ground substance are important to balance the water and salt metabolism within the skin. Probably, the salt-extractable hyaluronic acid is particularly important for the water-binding capacity of the connective tissue ground substance, while the sulfated muco-polysaccharides play a special role in the production of the collagen and elastic fibers.