U.S. researchers test way to rejuvenate muscles, brain

A study led by researchers with University of California at Berkeley has found that a small- molecule drug can inhibit the activity of a growth factor, allowing aging tissues to regenerate.

Dr. Irina Conboy, associate professor of bioengineering at UC Berkeley and co-author of the study, told Xinhua that high numbers of the growth factor, known as TGF-beta1, in the tissues are a typical sign of aging.

And the drug under the study is able to inhibit the receptor of TGF-beta1, blocking its pathway to the stem cells.

The researchers were able to tackle both the brain and muscle tissues because they have the same molecular mechanism for aging. Using a viral vector for genetic therapy developed by Dr. David Schaffer, director of the Berkeley Stem Cell Center and professor of chemical and bimolecular engineering, the team was able to insert genetic blockers into the brains of old mice to knock down TGF-beta1 activity.

"After blocking the pathway," Conboy said, "we saw that the hippocampal stem cells began generating new nerve cells."

Concluding that inhibiting the pathway leads to renewed cell activity, Conboy and Schaffer injected mice with a molecule known as Alk5 kinase inhibitor to block TGF-beta1. The animals not only began regenerating old brain and muscle tissues, but also became smarter as their stem cells were rejuvenated.

"All the mice regained between 70 and 80 percent of tissue youth and increased their cleverness," Conboy said.

However, the researchers cautioned that this is a small step towards creating an actual rejuvenating solution for humans, since there are many other biochemical cues regulating adult stem cell activity.

Though it has been successful with mice models, clinical trials will determine if the treatment is applicable to the human body. Conboy said the team would begin testing with human models as soon as they come up with the funding.

The researchers reported their finding in the current issue of the journal Oncotarget. Enditem