Differing cytotoxicity and bioavailability of selenite, methylselenocysteine, selenomethionine, selenosugar 1 and trimethylselenonium ion and their underlying metabolic transformations in human cells. Issue 12 (12th September 2016)

• Record Type: Journal Article
• Authors: Marschall, Talke Anu; Bornhorst, Julia; Kuehnelt, Doris; Schwerdtle, Tanja
• Is Part Of: Molecular nutrition & food research. Volume 60:Issue 12(2016)
• Page Start: 2622
• Page End: 2632
• Publication Date: 2016-09-12
• Subjects: Cellular bioavailability -- ICP‐QQQ‐MS -- Selenosugar 1 -- Small selenium species -- Speciation; Food -- Biotechnology -- Periodicals; Food -- Microbiology -- Periodicals; Nutrition -- Periodicals; Food -- Toxicology -- Periodicals; Nutrition -- Periodicals; Food Microbiology -- Periodicals; Food Technology -- Periodicals; Molecular Biology -- Periodicals; 664.0705
• DOI: 10.1002/mnfr.201600422
• Languages: English
• ISSNs: 1613-4125

Abstract

Abstract : Small Se species including the major urinary Se metabolites methyl‐2‐acetamido‐2‐deoxy‐1‐seleno‐β‐D‐galactopyranoside (selenosugar1 ) and trimethylselenonium ion (TMSe) are incubated in human urothelial, astrocytoma and hepatoma cells to elucidate the species‐ and cell‐specific cytotoxic effects. The analysis reveals that TMSe and selenosugar1 are not metabolized in significant amounts. These results indicate that TMSe and selenosugar1 are non‐cytotoxic up to super physiological concentrations rather due to a missing metabolic activation than a lacking cellular bioavailability. Abstract : Scope: The trace element selenium (Se) is an integral component of our diet. However, its metabolism and toxicity following elevated uptake are not fully understood. Since the either adverse or beneficial health effects strongly depend on the ingested Se species, five low molecular weight species were investigated regarding their toxicological effects, cellular bioavailability and species‐specific metabolism in human cells. Methods and results: For the first time, the urinary metabolites methyl‐2‐acetamido‐2‐deoxy‐1‐seleno‐β‐D‐galactopyranoside (selenosugar1 ) and trimethylselenonium ion (TMSe) were toxicologically characterised in comparison to the food relevant species methylselenocysteine (MeSeCys), selenomethionine (SeMet) and selenite in human urothelial, astrocytoma and hepatoma cells. In all cell lines selenosugar1 and TMSe showed no cytotoxicity. Selenite, MeSeCys and SeMet exerted substantial cytotoxicity, which was strongest in the urothelial cells. There was no correlation between the potencies of the respective toxic effects and the measured cellular Se concentrations. Se speciation indicated that metabolism of the respective species is likely to affect cellular toxicity. Conclusion: Despite being taken up, selenosugar1 and TMSe are non‐cytotoxic to urothelial cells, most likely because they are not metabolically activated. The absent cytotoxicity of selenosugar1 and TMSe up to supra‐physiological concentrations, support their importance as metabolites for Se detoxification.