Immortal Skin

by John B. Carnett Skin researcher Lynn-Allen Hoffmann stumbled on mysterious cells that hold promise in growing replacement skin for burn victims. John B. Carnett

Lynn Allen-Hoffmann loves skin. When she talks about it, her voice softens until her Wisconsin accent is almost undetectable, and she whispers words like "elegant," "brilliant," and "masterpiece." As a professor of pathology at the University of Wisconsin Medical School in Madison, Allen-Hoffmann has spent more than a decade studying the basic biology of skin cells: how they divide and how they become what she calls "our protective armor." Normally, her harvested skin cells -- like most other lab-grown cells -- survive about 15 weeks.



When they die, she throws them out and starts again. But about six years ago, as her laboratory manager Sandy Schlosser started tossing out old petri dishes, she noticed what looked like a small colony of living cells in the midst of dead ones.




Schlosser held it to the light and said, "Hey Lynn, what the heck is this?" Allen-Hoffmann had no idea. "Oh gosh, maybe it's a long-lived variant. Let's just keep it and see what happens." They did, and the skin cells never stopped growing. At the time, Allen-Hoffmann didn't realize the cells' potential, yet she kept studying them over the years. Today, they've become an important tool for testing cosmetics, a model for studying skin diseases -- such as skin cancer -- and their treatments, and analyzing the detrimental effects of chemicals on skin. But most exciting of all, they may turn out to be the best source yet of lab-grown skin to treat burn victims -- better than any product presently on the market and one that will become shelf-ready to be shipped out on demand. Last year, Allen-Hoffmann founded Stratatech, a company that holds the exclusive license for the cells. The company plans to test the skin on burn patients within three years.

When you ask Allen-Hoffmann how she created the cells, she laughs a contagious whoop that trails off into a chuckle. "I have no idea," she says. In fact, for a while, the cells were an in-house joke. Folks would nudge each other and say things like: "Gee, wonder if the cells are still alive." After the cell population doubled for the 400th time and the lab's freezer was bursting with the skin cells, people stopped joking.

While Allen-Hoffmann thought about growing her cells into swaths of skin, she didn't realize how important her idea was until she got a call last year from Michael Schurr, a surgeon at the University of Wisconsin Hospital Burn Center, who insisted that growing skin become her top priority. The only lab-grown skin available to him was terrible, he told her: It took weeks to grow, and even then it was too thin to call skin.

Soon after their conversation, a local farmer literally melted into the side of a propane tank when a spark from his tractor ignited an enormous explosion. The only skin that remained on his body covered his feet in the shape of his shoes.




Schurr cut small samples from the farmer's feet and shipped them off to a company called Genzyme, based in Cambridge, Massachusetts, where they spent weeks growing in culture as the farmer lay waiting in an anesthetic haze. Allen-Hoffmann didn't know the first thing about clinical medicine, so Schurr invited her to watch the graft surgery. When she did, it was a revelation.