DNA damage theory of aging
Brain

Lu et al. studied the transcriptional profiles of the human frontal cortex of individuals ranging from 26 to 106 years of age. This led to the identification of a set of genes whose expression was altered after age 40. These genes play central roles in synaptic plasticity, vesicular transport and mitochondrial function. In the brain, promoters of genes with reduced expression have markedly increased DNA damage. In cultured human neurons, these gene promoters are selectively damaged by oxidative stress. Thus Lu et al. concluded that DNA damage may reduce the expression of selectively vulnerable genes involved in learning, memory and neuronal survival, initiating a program of brain aging that starts early in adult life.
combination:two_responses, oulipo:avoid_letter[t], punctuation:no_comma