BACKGROUND: Polyamines are involved in normal and pathological cell proliferation
and differentiation. Like acid radicals, they play an important role in
remodelling the extracellular matrix and are considered "uremic toxins". Proteins
and glycosaminoglycans are essential components of the extracellular matrix, and
contribute to normal mature organ functions. The aim of this study was to analyse
the effects of free polyamines, dialysate fluid components and dialysis fluid on
protein and extracellular glycosaminoglycan synthesis in VERO cell cultures.
METHODS: The dialysate fluid components were separated with a Sephadex G15 column
and the cultures were analysed after incorporation of 3H-leucine and
3H-glucosamine. Cultures were run at pH 7.0 and pH 7.4. The glycosaminoglycan
classes were separated with a DEAE column, and polyamines were determined by
high-performance liquid chromatography. Proteins and single glycosaminoglycan
classes were quantified by a scintillator. DNA gel electrophoresis was done to
detect chromatin fragmentation. RESULTS: Dialysate contained putrescine,
spermidine and spermine, chromatography showing four peaks; only peaks I and II
indicated polyamines at respectively Da 5000 and 1500. Polyamines are therefore
linked to different carriers. There was an increase of protein and
glycosaminoglycan synthesis with dialysis fluid and polyamines, but inhibition
with peak II or dialysate. DNA gel electrophoresis showed no chromatin
fragmentation. Findings at pH 7.0 and 7.4 were similar. CONCLUSIONS: It would
appear that in uremic patients polyamines are conjugated to protein carriers of
different molecular weights with different biological actions. As polyamines and
dialysis fluid affect changes in extracellular matrix, they could be related to
physiological organ functions. However, these in vitro data must be considered
with the appropriate limitations when we try to extrapolate them to the in vivo
situation