Featured Research

from universities, journals, and other organizations

Biomarking time: Methylome modifications offer new measure of our 'biological' age

Date:
November 21, 2012
Source:
University of California, San Diego Health Sciences
Summary:
In a new study, researchers describe markers and a model that quantify how aging occurs at the level of genes and molecules, providing not just a more precise way to determine how old someone is, but also perhaps anticipate or treat ailments and diseases that come with the passage of time.

Women live longer than men. Individuals can appear or feel years younger -- or older -- than their chronological age. Diseases can affect our aging process. When it comes to biology, our clocks clearly tick differently.

In a new study, researchers at the University of California, San Diego School of Medicine, with colleagues elsewhere, describe markers and a model that quantify how aging occurs at the level of genes and molecules, providing not just a more precise way to determine how old someone is, but also perhaps anticipate or treat ailments and diseases that come with the passage of time.

The findings are published in the November 21 online issue of the journal Molecular Cell.

"It's well known that people age at different rates," said Kang Zhang, MD, PhD, professor of ophthalmology and human genetics at the Shiley Eye Center and director of the Institute for Genomic Medicine, both at UC San Diego. "Some people in their 70s look like they're in their 50s, while others in their 50s look like they're in their 70s."

However, identifying markers and precisely quantifying the actual rate of aging in individuals has been challenging. For example, researchers have looked at telomeres -- repeating nucleotide sequences that cap the ends of chromosomes and which shorten with age -- but have found that other factors like stress can affect them as well.

In the new Molecular Cell paper, Zhang and colleagues focus on DNA methylation, a fundamental, life-long process in which a methyl group is added or removed from the cytosine molecule in DNA to promote or suppress gene activity and expression. The researchers measured more than 485,000 genome-wide methylation markers in blood samples of 656 persons ranging in age from 19 to 101.

"It's a very robust way of predicting aging," said Zhang, one that was subsequently validated on a second sampling of several hundred blood samples from another cohort of human individuals.

The scientists found that an individual's "methylome" -- the entire set of human methylation markers and changes across a whole genome -- predictably varies over time, providing a way to determine a person's actual biological age from just a blood sample.

"It's the majority of the methylome that accurately predicts age, not just a few key genes," said co-senior author Trey Ideker, PhD, a professor of medicine and chief of the Division of Medical Genetics in the UC San Diego School of Medicine and professor of bioengineering in the Jacobs School of Engineering. "The methylation state decays over time along the entire genome. You look in the body, into the cells, of young people and methylation occurs very distinctly in some spots and not in others. It's very structured. Over time, though, methylation sites get fuzzier; the boundaries blur."

They do not, however, blur at the same rate in everybody. At the molecular level of the methylome, the researchers said it was clear that individual bodies age at varying rates, and even within the same body, different organs age differently. Moreover, cancer cells age differently than their surrounding normal cells. The findings, according to the study authors, have broad practical implications. Most immediately, they could be used in forensics to determine a person's age based only upon a blood or tissue sample.

More profoundly, said Zhang, the methylome provides a measure of biological age -- how quickly or slowly a person is experiencing the passage of time. That information has potentially huge medical import. "For example, 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."

Ideker said assessing an individual's methylome state could improve preventive medicine by identifying lifestyle changes that might slow molecular aging. He noted, however, that much more research remains to be done.

"The next step is to look to see whether methylation can predict specific health factors, and whether this kind of molecular diagnosis is better than existing clinical or physical markers. We think it's very promising," Ideker said.

Co-authors of this study include Gregory Hannum and Menzies Chen, UCSD Department of Bioengineering; Justin Guinney and Stephen Friend, Sage Bionetworks, Seattle, WA; Ling Zhao, UCSD Institute for Genomic Medicine and UCSD Department of Ophthalmology; Li Zhang, Sichuan University, UCSD Institute for Genomic Medicine, UCSD Department of Ophthalmology and Guangzhou iGenomics Co., China; Guy Hughes, UCSD Institute for Genomic Medicine and UCSD Department of Ophthalmology; SriniVas Sadda, University of Southern California; Brandy Klotzle, Marina Bibikova and Jian-Bing Fan, Illumina Inc, San Diego; Yuan Gao, Johns Hopkins University, Baltimore, MD; Rob Deconde, UCSD Department of Bioengineering and Department of Medicine; Indika Rajapakse, Fred Hutchinson Cancer Research Center, Seattle, WA.


Story Source:

The above story is based on materials provided by University of California, San Diego Health Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Gregory Hannum, Justin Guinney, Ling Zhao, Li Zhang, Guy Hughes, SriniVas Sadda, Brandy Klotzle, Marina Bibikova, Jian-Bing Fan, Yuan Gao, Rob Deconde, Menzies Chen, Indika Rajapakse, Stephen Friend, Trey Ideker, Kang Zhang. Genome-wide Methylation Profiles Reveal Quantitative Views of Human Aging Rates. Molecular Cell, 2012; DOI: 10.1016/j.molcel.2012.10.016

Cite This Page:

University of California, San Diego Health Sciences. "Biomarking time: Methylome modifications offer new measure of our 'biological' age." ScienceDaily. ScienceDaily, 21 November 2012. <www.sciencedaily.com/releases/2012/11/121121130633.htm>.
University of California, San Diego Health Sciences. (2012, November 21). Biomarking time: Methylome modifications offer new measure of our 'biological' age. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2012/11/121121130633.htm
University of California, San Diego Health Sciences. "Biomarking time: Methylome modifications offer new measure of our 'biological' age." ScienceDaily. www.sciencedaily.com/releases/2012/11/121121130633.htm (accessed August 23, 2014).

Share This




More Health & Medicine News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Two US Ebola Patients Leave Hospital Free of the Disease

Two US Ebola Patients Leave Hospital Free of the Disease

AFP (Aug. 21, 2014) Two American missionaries who were sickened with Ebola while working in Liberia and were treated with an experimental drug are doing better and have left the hospital, doctors say on August 21, 2014. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins