Laser skin resurfacing has become a popular way to wage war on wrinkles, and now a new study details how one type of laser may help turn back the clock.

The carbon dioxide (CO2) laser is one of the systems used in laser skin resurfacing. The laser beam is passed over the skin to vaporize problem areas at the surface, while the heat that hits the underlying tissue is believed to spur the growth of new collagen - the fibrous protein that helps keep skin taut.

Revved up collagen production has been thought to be one reason laser resurfacing works. Still, the details of the process have not been clear.

Getting a measurement of how the CO2 laser affects the biochemistry of the skin should allow for better comparisons among the different types of lasers used in cosmetic procedures, according to the authors of the new study.

To do this, the researchers analyzed genetic material in tissue samples taken from adult volunteers who underwent CO2 resurfacing of sun-damaged skin on their forearms. They found that one week after the procedure, levels of an enzyme involved in breaking down collagen - known as MMP-1 - were nearly 40,000 times higher than they were before surgery.

It’s likely that the enzyme was “induced” by the laser to break down the patients’ sun-damaged collagen, according to the researchers, led by Dr. Jeffrey S. Orringer of the University of Michigan Medical School in Ann Arbor.

This “clearance” of old collagen may make room for a new generation, the researchers report in the November issue of the Archives of Dermatology.

Indeed, their analysis found a “marked elevation” in procollagen proteins that occurred after levels of MMP-1 and related enzymes declined. The procollagen, which is turned into collagen, increased to seven to nine times its original levels and stayed elevated for at least six months after the laser treatment, Orringer and his colleagues report.

The findings, they say, may serve as a “measuring stick” against which other lasers can be compared. The challenge now, the researchers add, is to create a device that creates the same biochemical changes in the skin, but with fewer side effects.

The risks of laser skin resurfacing include long-term skin discoloration, sun sensitivity, and in a small number of cases, scarring.

SOURCE: Archives of Dermatology, November 2004.