Older stem cells returned to youth

We've written quite a bit about research by CIRM grantee Irina Conboy at the University if California Berkeley (blogged here), who has found that the muscle stem cells in older people don't respond as enthusiastically to repair muscle damage — much to the dismay of aging athletes. What they've also learned is that environment is key. Those same sluggish stem cells respond more rapidly when bathed in younger blood, at least in mice. Their work suggests that the muscle stem cells are still effective, it's the older surrounding cells that are the problem.

New research by a group at the University of Texas Health Science Center San Antonio has found something similar with stem cells that produce bone. They took mesenchymal stem cells from the bone marrow of mice. These cells are different than the blood-forming stem cells also found in bone marrow, which continuously form all cells of the blood system. The mesenchymal stem cells are bone marrow residents that can make bone, cartilage and fat, among other tissues.

The research, published in the FASEB Journal in May, showed that mesenchymal stem cells (MSCs) from old and young mice both multiplied four times more when grown in the lab on cells taken from younger mice versus older mice. What this means is that even though the tissue-specific stem cells might not be very active in an older body, those cells can be given a new lease on life in the lab. A press release from UT Health Science Center quotes the senior author on the work:

“The number and quality of those cells decline with age, that is very clear,” said Xiao-Dong Chen, M.D., Ph.D., a stem cell researcher at the UT Health Science Center. “And, using the patient’s own cells can impact results.”

This work was in mice, which means that it may or may not translate to humans. But this kind of research is important, given that many stem cell-based therapies that CIRM and others are funding address diseases that occur in older people with older stem cells. Knowing how to return those stem cells to a more youthful state could be important for developing effective therapies of aging.

- A.A.