GFAP and vitamin B12 deficiency: The model was then used for further analysis, in which we indicated that astrocytes, upon cobalamin deficiency, may undergo a homeostasis imbalance including inhibited cell proliferation, cell cycle arrest in G2/M phase, activation of caspase 3/7, 8 and 9, cell hypertrophy, and GFAP and vimentin overexpression [5,6].