Connective tissue activation

Abstract

Four normal (NF) and 4 scleroderma skin fibro-blast (SF) strains were compared with respect to 1) basal ¹⁴C-glucosamine and ³⁵SO₄-labeled glycosaminoglycan (GAG) synthesis, 2) responsiveness to autacoid mediators, and 3) performance following maximal stimulation. Under basal conditions, SF synthesized and secreted 2–3 times more radioactive hyaluronic acid than the NF (P < 0.001); molecular volume by gel chromatography was similar and suggested a high molecular weight product. SF were essentially as responsive to normal lymphoid and platelet factors as were NF. No consistent qualitative or quantitative differences in sulfated GAG synthesis were noted between the 2 groups of cells. Incubation of NF and SF with a false “core protein” such as p-nitrophenyl-β-D-xyloside suggested that synthesis of the core protein was rate limiting; SF and NF were equally facile in SO₄-GAG chain synthesis in the presence of a β-xyloside. SF appear to retain in vitro a partially activated state for many generations, at least with respect to hyaluronic acid synthesis.