MODIFICATIONS OF PROTEOGLYCANS SECRETED INTO THE GROWTH-MEDIUM BY YOUNG AND SENESCENT HUMAN SKIN FIBROBLASTS

The properties of proteoglycans (PGs) secreted into the growth medium by normal young and senescent human skin fibroblasts (HFs) were invest igated, In both cases, the incorporation per cell of radioactive precu rsors into total PGs was similar, The polysaccharide chains of PGs fro m young and senescent HFs mere mainly represented by galactosaminoglyc uronans and showed a similar range of size distribution, However, gala ctosaminoglycuronans of PGs secreted by senescent HFs had a lower cont ent of unsulphated disaccharides and a lower proportion of D-glucurono syl residues, Moreover, senescent HFs released into the growth medium higher relative amounts of small PGs with chondroitin sulphate, dermat an sulphate chains, such as decorin.