Are so-called uremic toxins always toxic?

摘要

OBJECTIVE: Numerous substances qualify as uremic toxins by fulfilling all properties characterizing such compounds. However, their role in the development of uremic state maybe ambiguous. We followed these properties on the example of N-methyl-2-pyridone-5-carboxamide (Met2PY) from the nicotinamide end-products family. The aim of this study was to determine if these uremic compounds are toxic in all circumstances. METHODS: To establish a direct toxic effect, a cytotoxicity test was performed. The influence of Met2PY on DNA damage in cultured cells was measured, using a comet assay. For in vitro experiments, Moly (L5178Y), LLCPK-1, and A549 cell lines were used. We used 250 microM H2O2 and 200 ng/mL angiotensin II (ANGII) as damaging factors. RESULTS: A direct cytotoxic effect of Met2PY on Moly cells was observed. In LLC-PK1 cells, co-incubation with 0.03 mM Met2PY protected cells against the DNA damage caused by ANG II. In A549 cells, the action of Met2PY was ambiguous. At lower concentrations (1 and 3mM), it showed protective effects, although 10 mM Met2PY increased the toxic effect of 250 microM H2O2. CONCLUSIONS: Our results suggest that Met2PY is not always toxic or harmful. In some circumstances, it may even express beneficial and protective properties.