Growth hormones can rejuvenate individual cells, researcher finds

May Reed

One could say that there have been a few strides in medicine since Ponce de Leon hacked his way along the Florida coast in search of the fountain of youth; bloodletting is no longer used to treat hemorrhaging, for instance. But in specific ways, the same quest for a "cure" to aging exists today.

In research labs around the world, scientists have narrowed down Ponce de Leon's search to the molecular level. "The question is, can one reverse the aging process," says Dr. May J. Reed, assistant professor of medicine in the Division of Gerontology and Geriatric Medicine.

The answer is, well, yes... to an extent.

As cells age, they begin to secrete less growth factors and other beneficial proteins essential for such functions as dividing and migrating. "If you give a cell a milieu of treatments with growth factors, you can return an old cell to a young behavior pattern," Reed says.

That may sound like a long way off from the fountain of youth, but it's certainly closer than our famous Spanish explorer managed to get in 1513.

Reed will discuss her research in a lecture, titled "Wound Repair and Angiogenesis in Aging," on Friday, March 6, from noon to 1 p.m. in room T-625 of the Health Sciences. Her lecture is sixth in this year's Science in Medicine Series.

Reed and her colleagues have something else in common with Ponce de Leon. He may not have found the fountain of youth, but he did find Florida. Reed and her colleagues have made a few discoveries of their own.

In 1994, Reed conducted research showing that when growth factors such as transforming growth factor beta (TGF-B) are replaced in aged human dermal fibroblasts, they can be made to function like young cells. Dermal fibroblasts connect tissue in our skin.

This established that aging is not fixed — that it can be altered in specific cells. Reed and her colleagues then turned toward applying what they knew to wound repair and angiogenesis, which is the formation of new blood vessels.

"We set out to prove that angiogenesis is impaired in aging and can be improved by increasing the availability of growth factors, which hadn't been looked at before," Reed said.

Blood vessel formation is delayed in older people partly because endothelial cells that line the walls of our microvessels are not dividing and moving at the same rate as in young tissue. This is one of the many reasons wounds heal more slowly in older people.

Initially, Reed and her colleagues took blood vessels from the fat of aged rodents and suspended them in a liquid collagen gel, which gave the researchers a 3-D view. They applied TGF-B and other growth factors to the microvessels and measured their migration and branch formation.

The result was that cell migration improved. Aged cells began behaving more like young cells.

More recently, Reed has been conducting similar studies with aged human microvascular endothelial cells. "We found that modulation of endothelial cell movement may be just as important as cellular proliferation in enhancing the formation of blood vessels," she said.

The finding opens the door for improving wound repair in elderly humans and puts Reed and her colleagues on the cutting edge of research in aging.

"Few attempts at reversing the impaired angiogenesis associated with aging have been studied. Now we have to determine the mechanisms that are important in this process," she said.

But is this the way to the fountain of youth? Maybe. It does tells us that the answer is within us at the cellular level, which is one piece of information Ponce de Leon was sorely missing.

Reed arrived at the University of Washington in 1990. She completed a clinical fellowship in geriatric medicine in 1991 and a postdoctoral research fellowship under Dr. Helen Sage, professor of biological structure, in 1996.

She received an M.D. from Harvard University Medical School in 1986 and completed a residency in primary care/internal medicine at Massachusetts General Hospital in Boston in 1989. Reed has been an assistant professor since 1995. ¶

Will Morton