We’ve known for a while now that some people age faster than others, but researches at UCLA have discovered a DNA body clock that shows that different parts of our bodies age faster than others. Biologists have researched other biological clocks derived from data gathered from our saliva and hormones, and have extensively researched telomeres – fraying tips of our chromosomes that have been linked to cellular expiration dates and, thus, individual rates of aging. But the new research is the first to produce an internal clock able to accurately assess the age of various organs, tissues and cell types, and has crucially shown that different parts appear to age at different rates.
DNA Alters As We AgeThis new research was conducted by Steve Horvath, professor of human genetics at UCLA’s David Geffen School of Medicine and of biostatistics at the Fielding School of Public Health. Horvath studied DNA methylation, a naturally-occurring process that chemically alters DNA. Scientists are learning more and more that epigenetic factors – changes that happen to DNA after we are born – cause many manifestations of aging. For his study, Horvath looked at 121 different sets of methylation-specific data, including 8,000 samples of 51 types of tissue and cells taken from all over the body. By honing in on the 353 markers that change with age, he was able to chart a DNA clock showing how age affects DNA methylation levels from pre-birth all the way up to 101 years old.
Parts of Our Bodies Age Differently
What he discovered was a bit shocking: While most of our body parts match our chronological ages, some parts are exceptions. Healthy female breast tissue, for example, is two to three years older than the rest of the female body. If a woman has breast cancer, the healthy tissue next to a cancerous tumor is an average of 12 years older than the rest of the body. And the tissues in a tumor are an average of 36 years older than healthy tissue, which provides important insight into why age is such a risk factor for so many types of cancers in both genders.
Perhaps most interesting is that Horvath’s research showed that stem cells are essentially “newborns.” Because of that, he believes that transforming one’s cells into pluripotent stem cells could literally rewind and reset our cells’ biological clock to zero. If that is true, it has wide-ranging implications for anti-aging therapies and treatments. That, of course, opens up its own can of worms – while this research could, as Horvath says, “help us to finally understand why we age,” it’s also true that problems related to aging are incredibly multifaceted. There is no single quick-fix to aging, despite the breakthroughs in understanding Horvath has provided.