Chick embryo back skin organ and fibroblast cultures. Extracellular matrix change induced by dialysate fluid and uraemic toxins in relation to proliferation and differentiation processes

Aim: During uraemia, an increase of middle molecules and acetylpolyamines occurs. In vitro the middle molecules produce cell toxicity, while the acetylpolyamines stimulate cell proliferation and differentiation. These phenomena are related to protein and extracellular glycosaminoglycan production. The aim of the present study was to evaluate the activity of dialysate, dialysate fluid and the chromatographic peaks of dialysate fractionated by G-15 Sephadex column on chick embryo skin development. Methods: We evaluated the effects of protein and glycosaminoglycan synthesis using monolayer and organotypic cultures. Results: Our data show that dialysate, chromatographic peak II, and 261028M N1-acetylspermine cause inhibition of chick embryo skin culture development. On the contrary, 1028M N-acetylornithine and dialysate fluid increase protein and extracellular glycosaminoglycan synthesis, whereas chromatographic peak I does not reveal differences when compared to controls. Conclusions: These extracelluar changes are related to cell proliferation and feather formation in chick embryo organotypic culture. Moreover, the pH changes of culture medium do not influence the biological action of acetylpolyamines and dialysate fluid on protein and extracellular glycosaminoglycan synthesis. Cell death in the presence of N1acetylspermine, dialysate and peak II appears unrelated to the apoptotic process. The data show that acetylpolyamines, dialysis fluid, dialysate and chromatographic peaks act on fibroblasts, and are able to modify glycosaminoglycan synthesis. The organotypic cultures of chick embryo back skin could represent a model for studying the modifications of the extracellular matrix induced by these substances.