Longevity Briefs: New Biological Clock Helps Explore Aging of the Human Brain

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: Biological, or epigenetic, clocks are biochemical tests which can predict biological age. The clock is based on DNA methylation levels. DNA methylation is the process in which methyl groups attach to regions of the DNA called methylation sites where they act as genetic switches, turning specific genes on or off . The increasing inaccuracy of these methyl groups to attach to the correct sites as we get older is thought to be one of the root causes of aging.

By mapping which methylation sites are being unduly methylated as we age allows us to build up a predictive model that can be used to assess the biological age, giving rise to the epigenetic clock.

In recent years, epigenetic clocks have been applied to brain tissue in an attempt to uncover the mysteries of how exactly our brains age and the development of age-related neurological disorders such as dementia or Parkinson’s.

What did the researchers do: A research team led by Prof. Jonathan Hill, based at the University of Exeter, analysed the methylation status of 1,397 human brain samples from individuals aged 1-108. The tissue samples were from a part of the brain called the cerebral cortex, a region that plays a vital role in cognition and the progression of Alzheimer’s disease. From the analysed samples the research team built a epigenetic clock based on the methylation status of 347 sites.

Key takeaway(s) from this research: As previous models had been based on solely blood samples of middle-ages individuals, the epigenetic clock developed by Prof. Hill and his team dramatically outperforms any clock that came before it. Giving more accurate estimations of the ageing rate of the individual, and providing a better understanding of how the brain ages.

Our study highlights the importance of using tissue that is relevant to the mechanism you want to explore when developing epigenetic clock models. In this case, using brain tissue ensures the epigenetic clock is properly calibrated to investigate dementia.
Gemma Shireby, first author and Ph.D. student at the University of Exeter. Source: Medical Xpress