Scientists Discover Bio-Clock Capable of Predicting Age of Different Tissues

A recent study found that breast tissues age faster than the rest of the body. Researchers from university of California, Los Angeles have identified the biological clock present in our genomes. The finding will help in furthering stem cell research and also explain the aging process better.

Previously, hormones, telomeres and saliva were the only known bio-markers for predicting age, but this research sheds light on a new age-predicting bio-clock, which can tell the age of different tissues present throughout the body. This latest biological tool helped the researchers in estimating that the breast tissues in women age quicker than the rest of the body parts.

"To fight aging, we first need an objective way of measuring it," Steve Horvath, a professor of human genetics at UCLA's David Geffen School of Medicine and of biostatistics at the UCLA Fielding School of Public Health, stated in a press release.

"Pinpointing a set of biomarkers that keeps time throughout the body has been a four-year challenge," Horvath added.

Horvath's aim in developing this age-predicting devise was to decipher how the aging process takes place in the human body. He analyzed a naturally occurring chemical modification process called methylation, which is one the four building blocks that structures our DNA. He examined about 121 sets of data, which were collected by other scientists who researched on the methylation process in carcinogenic and healthy human tissues. He concentrated on 353 bio-markers, which were linked to methylation change with age. He also outlined the impact of aging on the chemical process of DNA methylation from pre-natal stage to the age of 101 years.

"It's surprising that one could develop a predictive tool that reliably keeps time across the human anatomy," Horvath said. "My approach really compared apples and oranges, or in this case, very different parts of the body - including brain, heart, lungs, liver, kidney and cartilage."

He found that his age-predicting tool gave him precise results regarding the chronological and biological tissue aging, which was a significant achievement for him.

"Healthy breast tissue is about two to three years older than the rest of a woman's body," he said. "If a woman has breast cancer, the healthy tissue next to the tumor is an average of 12 years older than the rest of her body."

The tool can also help in detecting breast cancer cells in women. Cancer tumor cells are around 36 years older than the healthy cells. This shows that age might be a key risk factor for cancers in both women and men, and this aging of cancer cells also helps explain why breast cancer is common in women.

Horvath also looked into Pluripotent stem cells, or adult cells, which were transformed into embryonic stem cells capable of turning into any other cells even right back to infancy.

"In principle, the discovery proves that scientists can rewind the body's biological clock and restore it to zero," Horvath said.

This research led to another finding that the bio-clock does not run at the same pace throughout life. It was also found that children suffering from the uncommon genetic disorder progeria have a faster aging process, but their cells were found to be normal and matching with their chronological process.  

"It ticks much faster when we're born and growing from children into teenagers, then slows to a constant rate when we reach 20," he said.