Epigenetic clocks and DNA methylation biomarkers of brain health and disease

Abstract

Ageing has profound effects on the human brain across the lifespan. Cognitive testing and brain imaging are currently used to monitor healthy and pathological brain ageing. However, peripheral markers of cognitive function, cognitive ageing and neurological disease could provide a valuable, minimally invasive approach to tracking these processes longitudinally. In this Review, we introduce the concept of DNA methylation-based biomarkers and present current evidence of their potential to address the challenge of monitoring brain ageing and stratifying the risk of neurological disease. We focus on epigenetic clocks, which can be applied across multiple tissues and organs to estimate biological ageing, as well as on blood-based epigenetic scores (EpiScores) that can directly track brain-based phenotypes, such as cognitive function, and risk factors for neurological diseases, such as lifestyle behaviours and proteomic markers of inflammation. We discuss the associations between these epigenetic biomarkers and multiple measures of cognitive health, including cognitive test data, brain MRI measures and dementia.