How Quickly Does Aging Occur?

How Quickly Does Aging Occur? The “Methylome” Offers a Model

Aging is an unevenly distributed process, affecting individuals differently and accelerating with disease and other stress factors. Even an individual’s organs may age at different rates, making it hard to predict when aging occurs.

Now, medical researchers believe they have found “a very robust way of predicting aging, ” reports Kang Zhang, MD, of the University of California, San Diego, Institute for Genomic Medicine. In a new paper published in the journal Molecular Cell, Zhang and colleagues focus on how gene activity and expression are promoted or suppressed in the lifelong process of DNA methylation (where a methyl group is added or removed from the cytosine molecule in DNA).

The researchers measured methylation markers in blood samples of 656 persons ranging in age from 19 to 101, validating their model with hundreds of samples from another cohort. They concluded that mapping the entire “methylome” of these markers and changes across the genome offers a reliable way of predicting change over time. In other words, they can determine an individual’s actual biological age from a blood sample and predict rates of decay at the molecular level.

Such information could not only assist in forensics, but also improve therapies, according to Zhang. “For example,” he notes, “you could serially profile patients to compare therapies, to see if a treatment is making people healthier and younger. You could screen compounds to see if they retard the aging process at the tissue or cellular level.”

Source: University of California, San Diego Health Sciences

The research is published in the November 21, 2012, online edition of Molecular Cell. Read abstract.