UC Berkeley researchers announced Thursday that they have discovered a way to rejuvenate aged blood stem cells in mice, sparking hope for a similar treatment in humans.
In the journal Cell Reports, scientists described how their methods allowed the mice to be more active and to maintain stronger immune systems — even in old age — laying the foundation for future studies on humans. If successful, such treatment could help the elderly better combat disease.
“In the past 20 years there have been breakthroughs in understanding aging at the molecular level,” said Danica Chen, an assistant professor of nutritional science and toxicology and the principal investigator of the study. “The most exciting idea is that aging is a regulated process — we used to think aging was a random process.”
Chen’s lab was able to observe and manipulate the aging process in mice through a two-part experiment.
The study focused around the SIRT3 gene, which produces a protein that helps blood cells cope with oxidative stress — the inevitable damage cells incur when producing energy. The protein had been long thought to play a crucial role in preventing the aging process.
The researchers first showed that removing the SIRT3 genes from old mice led to a decrease in the production of blood cells. Scientists then reintroduced the genes into aged stem cells and were able to successfully increase blood cell production in older mice.
Katharine Brown, who co-authored the study and conducted the research as a UC Berkeley doctoral student, made the distinction that the experiment may lead to improvements in “healthspan” and not necessarily “lifespan.”
“Even in the normal aging system, you have reduced function of the blood system and decreased immune response,” Brown said. “Those are just a ‘natural’ part of the aging process. Even if you’re healthy and much older, your blood system isn’t as highly functional.”
Many news reports have hailed this research as the next step in developing a “molecular fountain of youth.”
“There is good evidence to show that what we were seeing in mice can be (applied) human beings,” Brown said
According to Emmanuelle Passegue, an associate professor of medicine at UCSF’s Center of Regeneration, this research is “utterly important” in finding new ways of treating age-related blood failure. However, she emphasized, the findings are not yet applicable to humans.
“I would be a bit more cautious with the notions of ‘rejuvenation’ and ‘turning back’ the molecular defects,” Passegue said in an email. “Especially when working with genetic mutant mice.”
Both Brown and Chen said they were hopeful, however, that their research could one day aid the development of treatments for blood diseases, such as leukemia.
“I think that this is definitely very fascinating and is going to have a very big impact,” Chen said. “We are just at the beginning of understanding that.”
Chen’s lab collaborated with other researchers on the project including study co-author Stephanie Xie, who was a postdoctoral fellow at Massachusetts General Hospital during the study, and David Scadden, co-director of the Harvard Stem Cell Institute.