Vitamin B12, Folates, and Docosahexaenoic Acid on the Prevention of Neuronal Dysfunction

OBJECTIVES: Global aging increases cognitive pathologies; however, some individuals present earlier symptoms with an etiology independent of age. A possible cause is the increased oxidative stress with the formation of amyloid fibrils in the neuronal tissue (in particular Aβ(1–40|42)). Studies use Aβ(25–35) fragment to form β sheet fibrils with a toxicity similar to Aβ(1–40|42). Converging studies sustain the idea that B12, B9, and docosahexaenoic may preserve regular neuronal activity. However, the literature is scarce about their synergy effects. The study aims to verify the hypothesis of reducing cellular apoptosis, using B12, B9, and docosahexaenoic acid (DHA) as preventives, isolated or in synergy, on delaying neuronal dysfunction, using “in vitro” assays. METHODS: An In vitro cell model using the SH-SY5Y cell line was analyzed before and after differentiation, induced by trans-retinoic acid and B27 supplement. Fibrillation with Aβ25–35 peptide fragment was carried out after differentiation. Cytotoxicity on undifferentiated cells and neurons was evaluated by reducing the redox potential of the MTT assay. TUNEL assay evaluates cell apoptosis by flow cytometry after B12 vitamers, folic acid, and DHA treatment. RESULTS: Supplemented cells with DHA (100 to 400 µM) showed an accented decline in cellular viability, below 10% at 400 µM. DHA IC50 at 344 µM was achieved after 24 h, 309 µM at 48 h, and 291 µM at 72 h. For Cyanocobalamin (CNC), dosages of 0.0045 to 0.072 µg/µl were not toxic, with a constant growth from 24 h to 72 h. CNC increase cell viability to 117 ± 3% at 48 h with 0.045 µg/µl and 82 ± 2% at 0.072 µg/µl. Methylcobalamin presents cell viability to 74 ± 6%, at 0.072 µg/µl after 24 h and 94 ± 5% is observed after 48 h. Folic acid concentrations of 0.1 and 0.5 µg/µl reveal cell viability of 94 ± 5% after 24, 48, and 72 h. Preliminary results from the TUNEL assay indicate a reduction in the level of apoptosis with supplementation for all micronutrients. CONCLUSIONS: Our results highlight the importance of vitamin B12, folates, and DHA for proper cerebral cell development and renewal. Furthermore, these founds indicate that well-addressed in vitro studies remain valuable tools to confirm if beneficial effects depend on the dose and frequency of intake of these specific nutrients. FUNDING SOURCES: NewFood4Thought PTDC/SAUNUT/30,455/2017.