Glycosaminoglycan components in duodenum with advancing age and in patients with progressive systemic sclerosis

The glycosaminoglycan (GAG) components in normal human duodenal tissue and in duodenal GAGs of patients with progressive systemic sclerosis (PSS) were characterized at the macromolecular level by electrophoresis combined with various GAG-specific digestion. High-performance liquid chromatographic assay quantified various unsaturated disaccharides derived from chondroitin sulfate and dermatan sulfate isomers (DS). The data obtained showed that on average, the total GAG content was 1.02 mg as uronic acid/g dry tissue weight, and the main GAGs were DS (33% of total GAGs), and heparan sulfates (HS, 27%), followed by hyaluronic acid (HA, 14%) and over-sulfated DS (10%), and small amounts of chondroitin, chondroitin-4- and -6-sulfates (C-4S and C-6S, totally 16%). With advancing age, the proportion of DS, HS and oversulfated DS increased, while HA, chondroitin and C-4S decreased. The composition of duodenal GAGs in PSS patients was similar to that in the aged: a higher proportion of DS isomers and HS and a lower proportion of HA and chondroitin. As the structure of sulfated GAGs differs with advancing age and in patients with PSS, GAGs may have a role in duodenal function and metabolism.