Protective Effects of Folic Acid and Vitamin C Against Iron Overload at the in vitro Blood-Brain Barrier

Abstract

Brain iron accumulation increases with age and this is more common in patients with neurodegenerative diseases such as Parkinson's disease. Also iron overload in addition to zinc accompanies with plaques containing β-amyloid (AP) of Alzheimer’s Disease. The blood-brain barrier (BBB) is a dynamic interface between the blood and the brain that plays an important role in maintaining central nervous system (CNS) homeostasis. In our study, protective effects of vitamin C and folic acid against iron overload in the in vitro blood-brain barrier model were investigated. Four different groups were created for the experimental procedure: 1) Control, 2) FeSO4, 3) FeSO4 + Vit C, 4) FeSO4 + Folic acid for toxicity experiments. After iron overload, permeability differences of Vitamin C and folic acid in vitro BBB model were assayed using Bovine Serum Albumin (BSA) Bradford protein assay. Both substances were found to have a protective effect against iron sulphate-induced damage. Also, vitamin C and folic acid significantly decrease the permeability after increasing caused by iron sulfate in BBB model. Considering the toxic effects of high concentrations of vitamin C, systemic effects of folic acid should also be investigated by in vivo studies to compare with vitamin C in ageing.

Keywords

• vitamin C
• folic acid
• iron overload
• blood-brain barrier

References

1. Lin, J.L., et al., Ascorbic Acid Prevents Blood-Brain Barrier Disruption and Sensory Deficit Caused by Sustained Compression of Primary Somatosensory Cortex. Journal of Cerebral Blood Flow & Metabolism, 2010. 30(6): p. 1121-1136.
2. Tudisco, C., et al., Comparison Between Folic Acid and gH625 Peptide-Based Functionalization of Fe3O4 Magnetic Nanoparticles for Enhanced Cell Internalization. Nanoscale Research Letters, 2018. 13(1): p. 45.
3. Skjørringe, T., L.B. Møller and T. Moos, Impairment of Interrelated Iron- And Copper Homeostatic Mechanisms in Brain Contributes to the Pathogenesis of Neurodegenerative Disorders. Frontiers in Pharmacology, 2012. 3: p. 169.
4. Won, S.M., et al., Iron Mediates Endothelial Cell Damage and Blood-Brain Barrier Opening in the Hippocampus After Transient Forebrain Ischemia in Rats. Experimental & Molecular Medicine, 2011. 43(2): p. 121-129.
5. Varatharaj, A. and I. Galea, The Blood-Brain Barrier in Systemic Inflammation. Brain, Behavior, and Immunity, 2017. 60: p. 1-12.
6. Emoto, M.C., et al., Synthesis and Evaluation as a Blood-Brain Barrier-Permeable Probe of 7-N-(PROXYL-3-yl-methyl) theophylline. Chemical and Pharmaceutical Bulletin, 2018. 66(9): p. 887-891.
7. Agus, D.B., et al., Vitamin C Crosses the Blood-Brain Barrier in the Oxidized Form Through the Glucose Transporters. Journal of Clinical Investigation, 2017. 100(11): p. 2842-2850.
8. Gordon, N., Cerebral Folate Deficiency. Developmental Medicine and Child Neurology, 2009. 51(3): p. 180-182.

9. Yang, S., et al., Identification of two immortalized cell lines, ECV304 and bEnd3, for in vitro permeability studies of blood-brain barrier. PLoS One, 2017. 12(10): e0187017
10. Lagrange P, et al., Transendothelial Permeability Changes Induced by Free Radicals in an in Vitro Model of the Blood-Brain Barrier. Free Radical Biology and Medicine, 1999. 27(5-6): p. 667-72.
11. Veszelka, S., et al., Comparison of a Rat Primary Cell-Based Blood-Brain Barrier Model With Epithelial and Brain Endothelial Cell Lines: Gene Expression and Drug Transport. Frontiers in Molecular Neuroscience, 2018. 11: p. 166.
12. Lockman, J.A., et al., Differential effect of nimodipine in attenuating iron-induced toxicity in brain-and blood–brain barrier-associated cell types. Neurochemical Research, 2012. 37(1): p. 134-142.
13. Haorah, J., et al., Oxidative stress activates protein tyrosine kinase and matrix metalloproteinases leading to blood–brain barrier dysfunction. Journal of Neurochemistry, 2007. 101(2): p. 566-576.
14. Zheng, W., Monnot, A.D., Regulation of Brain Iron and Copper Homeostasis by Brain Barrier Systems: Implication in Neurodegenerative Diseases. Pharmacology & Therapeutics, 2012. 133(2): p. 177-188.
15. Mohammed, M. A., et al., Factors controlling permeability of the blood-brain barrier. Cellular and Molecular Life Sciences, 2016. 73: p. 57-77.
16. Kook, S.Y., et al., High-dose of Vitamin C Supplementation Reduces Amyloid Plaque Burden and Ameliorates Pathological Changes in the Brain of 5XFAD Mice. Cell Death & Disease, 2014. 5(2): e1083.
17. Agus, D. B., et al., Vitamin C crosses the blood-brain barrier in the oxidized form through the glucose transporters. Journal of Clinical Investigation, 1997. 100(11): p. 2842–2848.
18. Smith, A. D., et al., Is folic acid good for everyone? The American Journal of Clinical Nutrition, 2008. 87(3): p. 517–533.