Phospholipids and glycosphingolipids in cultured skin fibroblasts from patients with progressive systemic sclerosis (scleroderma).

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.