Food additive sodium bisulfite induces intracellular imbalance of biothiols levels in NCM460 colonic cells to trigger intestinal inflammation in mice.

Sulfites and other preservatives are considered food additives to prevent pathogen growth in food, and they are generally regarded as safe since the late 1950s. However, the possible effects of sulfites on potential damage to host intestinal tissue remain largely unexplored. Given that endogenous sulfite mainly comes from the metabolism of biothiol, we attempted to clarify the relationship among biothiol levels, gut and food additives sulfite, including sodium bisulfite (NaHSO3), and the possible mechanism of sulfite affecting the intestine. In the present study, the NaHSO3 treatments markedly increased the homocysteine (Hcy) level but decreased the cysteine (Cys) level by promoting the expression of Hcy synthase and inhibiting the activities of cystathionine ß-synthase and cystathionine γ-lyase in NCM460 cells. The level of methionine (Met) was not significantly changed, but NaHSO3 promoted ROS-mediated NF-κB signaling pathway, and increased the expressions of proinflammatory cytokines by regulating the levels of Hcy and Cys in NCM460 cells. Vitamin B6 (VB6) supplementation successfully ameliorated NaHSO3-induced damage in NCM460 cells and the colon of Balb/c mice. Altogether, our study provided valuable insights into the safety evaluation of food preservatives. Besides, VB6 could be used as a promising candidate in novel therapies for sodium bisulfite-induced intestinal inflammation.

Changes in Biothiol Levels Are Closely Associated with Alzheimer's Disease.

BACKGROUND: Serum homocysteine (Hcy) level is considered to be an important biomarker for Alzheimer's disease (AD); however, the status of Hcy in brain tissue, and the association between brain and serum levels of Hcy in AD patients remain unclear. OBJECTIVE: We aimed to examine whether the changes of three thiols are consistent in serum of AD patients and the brain of APP/PS1 mice, and to verify the effectiveness of Hcy as a biomarker for early AD detection. METHODS: The levels of Hcy, cysteine (Cys), and glutathione (GSH) in Aß1-42-treated PC12 cells, the brain and hippocampus of APP/PS1 mouse, and the serum of AD patients were evaluated using ethyl (E)-3-(9-chloro-11-oxo-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f] pyrido [3,2,1 -ij] quinolin-10-yl)-2-cyanoacrylate (Probe 1) and ELISA assay or LC-MS. RESULTS: Measurement by Probe 1 revealed a significant increase in Hcy level, and a decrease in Cys and GSH levels in Aß1-42-treated PC12 cells and the serum of AD patients. The hippocampus and whole brain of APP/PS1 mice also showed a significant increase in Hcy level alongside the accumulation of age-related AD symptoms. The upregulation of Hcy and the downregulation of Cys and GSH were reversed in the Aß1-42-treated PC12 cells and the brain of APP/PS1 mice when supplemented with VB6. CONCLUSION: Changes in Hcy, Cys, and GSH levels in the brain of APP/PS1 mice and Aß1-42-treated PC12 cells were observed in situ with a new fluorescent probe, which were consistent with the abnormal changes in Hcy, Cys, and GSH levels in the serum of AD patients. VB6 supplementation was successful in ameliorating abnormal increases in Hcy levels.