When eight-year-old Robert Ray Middleton was doused with gasoline and set afire last June, almost no one imagined that he would survive. How could anyone live with burns over 99 percent of his body? Incredibly, however, the Montgomery County boy did survive the attack, which was allegedly committed by a thirteen-year-old neighbor. And he owes his favorable prognosis, in part, to a Texas company that treats and freeze-dries human skin.
Looking for all the world like white cardboard, AlloDerm grafts are a product of the LifeCell Corporation, a small biotech company located north of Houston in the Woodlands. They are made using a procedure developed by Stephen Livesey, an Australian-born physician and researcher who co-founded the company in 1986. “Our original idea,” he says, “was to sell our special freeze-dryers,” but he and his partners saw more money in the skin trade and switched in 1994.
The patented processes start when skin—donated to tissue banks by people when they die—arrives on ice at LifeCell’s in-house factory. First it is washed in various solutions for three days to remove both the epidermis (the upper layer) and the cells of the dermis (the lower, living layer). Then the remaining part of the dermis, a biochemical framework called the matrix, is placed in a $60,000 piece of equipment about the size of a refrigerator, where it is freeze-dried in such a way that ice crystals do not form. Finally, it is sealed in foil. AlloDerm, which costs $6,000 a square foot, has a shelf life under refrigeration of two years, but when dropped in sterile saline, it can be applied in thirty minutes.
Of the many fascinating things about LifeCell’s process, the most significant is that the matrix, because it is not damaged by ice, still contains the vital “programs” that tell the recipient’s body how to fill it in with new cells. Without the matrix, the body forms scar tissue. With it, the new dermis is almost normal. That’s why grafts of AlloDerm, donated by LifeCell, were used on Robby Middleton’s joints: so the resulting skin would be as flexible as possible. (Cultured epidermis grown from his own skin by a Massachusetts biotech company was used on the rest of his body and on top of the AlloDerm.)
As effective as it is for burns, the treated matrix has myriad unexpected applications. Placed inside the body, it doesn’t promote skin but melds with whatever it’s next to. Physicians have used it to fix harelips, to make slings to suspend drooping bladders, and to do repair work on the throat and mouth. Periodontists use small patches for gum grafts, and cosmetic surgeons insert little rolls of it to make pouty lips. Strangest of all, it can stand in for the dura, the tissue that covers the brain.
Even as AlloDerm’s potential grows, LifeCell is working on the long-term storage of blood platelets, heart valves, blood vessels, and nerve connective tissue. Down the line, Livesey and his colleagues hope to make the ultimate product: synthetic human skin. “It’s too complex to accomplish now,” he concedes, “but one day it will be done, and we’re the company that’s going to do it.” For burn victims like Middleton, that day cannot come a minute too soon.
