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Objective: A comparative investigation of glycosphingolipids and phospholipids of cultured skin fibroblasts from healthy donors and patients with progressive systemic sclerosis (SSc) was performed., Methods: Culture techniques, qualitative and quantitative lipid analyses, determination of neuraminidase activity, and immunofluorescence microscopy were used., Results: The quantitative content of individual phospholipids in the fibroblasts of SSc patients (PF) was equally elevated, on the average 2.8 times in comparison with the fibroblasts of healthy donors (DF). The total content of neutral glycosphingolipids was slightly elevated only because of a 1.5-fold increase of monoglucosylceramide in PF. A decrease in the amount of the gangliosides GM3 and GM1 and the absence of the disialogangliosides in PF in comparison with DF, were demonstrated. Immunofluorescent assay also showed a decrease of ganglioside epitopes on the cellular surface of PF in comparison with DF. The GM3-neuraminidase activity of PF homogenates was increased two-fold in comparison to normal values., Conclusions: These results are discussed in connection with abnormalities in membrane receptor functions, alterations in the cell phenotype and AMP-cyclase system activity, as well as hyperproduction of extracellular matrix proteins by PF.

Levels of cAMP were decreased and cGMP increased in progressive systemic sclerosis (PSS) fibroblasts compared with normal fibroblasts. PSS cells took up unusually large quantities of Ca++. The epinephrine-induced increases in cAMP were diminished sixfold and epinephrine-induced Ca++ uptake was abnormal in PSS cells. Considerable heterogeneity was observed in rheumatoid arthritis fibroblasts. Membrane-bound abnormalities in (PSS) cells may be of importance in the defective control of collagen production in progressive systemic sclerosis.