Scientists Uncover Internal Biological Clock: Slowing Down Aging

Everyone grows older over time. We age and change as our bodies react to our external environment. Yet scientists have wondered exactly why we age for years. Now, they've discovered a biological clock embedded in our genomes that may shed new light on why our bodies age and how we could potentially slow down the process.

Scientists have created internal clocks in the past. However, they've been linked to saliva, hormones and telomeres. This new research is the first to identify an internal timepiece able to accurately gauge the age of diverse human organs, tissues and cell types. In addition, the clock reveals that some parts of the anatomy, like a woman's breast tissue, age faster than the rest of the body.

"To fight aging, we first need an objective way of measuring it. Pinpointing a set of biomarkers that keeps time throughout the body has been a four-year challenge," said Steve Horvath, one of the researchers, in a news release. "My goal in inventing this clock is to help scientists improve their understanding of what speeds up and slows down the human aging process."

In order to create the clock, the researchers focused on methylation. This naturally occurring process chemically alters DNA. The scientists gleaned information from nearly 8,000 samples of 51 types of tissue and cells taken throughout the body. They then charted how age affects DNA methylation levels from pre-birth through 101 years. Then, the scientists zeroed in on 353 markers that change with age and are present throughout the body.

The result was a biological clock that could tell scientists a tissue's age. What was more surprising, though, was the fact that the clock showed that the biological age of some tissues diverged from their chronological age. For example, a woman's breast tissue ages faster than the rest of her body. This could help explain why breast cancer is the most common cancer in women.

That's not all the scientists found. It turns out that the clock's rate speeds up or slows down depending on the person's age. For example, the clock's ticking becomes faster when we're born and growing from children into teenagers. Then, it slows down to a constant rate.

The findings could have huge implications for the science of aging. In theory, it could help researchers stop the body's aging clock, which could potentially halt the aging process. That said, far more research needs to be conducted before any conclusions are drawn.

The research is published in the journal Genome Biology.