“Proliferation of cells is important in the repair and regrowth of tissues. In fact, we grow old in part because our bodies’ ability to regenerate tissues decreases as we age,” Sharpless said. “We believe an untoward effect of increased p16INK4a and ARF expression outside of cancer is a decrease in cellular proliferation needed to sustain this regeneration.”

The researchers also found that the increase in p16INK4a and ARF can be substantially inhibited by decreasing caloric intake, a known retardant of aging. This result suggests that decreased expression of p16INK4a and ARF could mediate the known anti-aging effects of caloric restriction.

“Our results suggest that going on a short-term diet will not reverse the aging process; only long-term restrictions appeared to have an effect on p16INK4a and ARF expression. Therefore, our results would not be consistent with the idea that short-term caloric restriction prior to surgery would improve post-operative wound healing,” Sharpless said.

The work has strong implications for stem cell renewal, he added. Stem cells are self-replenishing cells that constantly divide and differentiate into the component cells that make up the tissues in the human body and are found in particularly high number in the bone marrow, as well as organs such as the skin, kidney and liver.

“As tissue stem cells age, they appear to express more p16INK4a and ARF, which would stop those cells from replenishing,” Sharpless said. “As people age, they could just run out of functioning stem cells.”

Depletion of stem cells could affect the ability of the body to heal after injury or surgery and may also predict the ability of certain diseases, such as cardiomyopathy, to progress,” he added.

Along with Sharpless, study co-authors from UNC Lineberger are postdoctoral researchers Drs. Janakiraman Krishnamurthy and Grigoriy Kovalev, research technician Chad Torrice, graduate student Matthew Ramsey, and UNC Lineberger member Dr. Lishan Su, also associate professor of microbiology and immunology. Co-author Dr. Khalid Al-Regaiey is from Southern Illinois University’s departments of physiology and internal medicine.

Text for this article comes from a UNC press release.