opposed to triggering cellular aging in immature cells48. Alternatively, the direct reprogramming approach that involves direct conversion of human fibroblasts into other lineage-specific cells, such as neurons, does not erase cellular aging markers49. Indeed, neurons derived from aged fibroblasts through direct reprogramming have been shown to maintain cellular age50, therefore offering an alternative cellular model to study age-related disorders. It is worth noting that there has also been success in promoting cellular maturation, such as by using improved formulation of cultured medium51 and neuron-astrocyte co-culture system52,53.
