Epigenetics and cognitive disorders-translational aspects

Epigenetic processes, including DNA methylation and histone tail modifications, play a fundamental role in the neuronal plasticity required for learning and memory and their impairment is likely to contribute to cognitive decline and neurodegeneration. Despite that there is accumulating evidence of changes in DNA methylation and histone tail modifications in affected brain regions in Alzheimer's disease, Parkinson's disease, and Huntington's disease, the diagnostic value of those changes is still questionable. Particularly, available studies are often conflicting and limited by small sample size. Furthermore, changes observed in postmortem brains are not always mirrored by changes in blood DNA of living individuals, and studies in blood cells of early disease stages are still scarce.Very interestingly, the treatment of disease animal models with epigenetic compounds, including inhibitors of histone deacetylases and methyl donor compounds, resulted neuroprotective and often ameliorated cognitive decline or motor symptoms, opening the way for a potential application in humans. In parallel, there is accumulating evidence that several natural compounds exerting epigenetic properties, such as dietary B-vitamins, curcumin, resveratrol, epigallocatechin-3-gallate, and many others, could hold the promise of being very useful preventative approaches in the elderly to counteract the age-related cognitive decline.