Stem cells bringing hope for burn victims

From the washingtonpost.com Fetal Tissue Heals BurnsTests Show Treatment Led to Normal Skin Regrowth By David BrownWashington Post Staff WriterThursday, August 18, 2005; A02 An experimental therapy that uses skin cells grown from an aborted fetus successfully healed severe burns in eight children, sparing them the need for skin grafts, according to a study published today. The treatment led to the regrowth of essentially normal skin on second- and third-degree burns in about two weeks, according to the report by a Swiss research team. The scarring and tissue contraction seen after many burns did not occur, and dressing changes were easier and less painful, the researchers said. The fetal tissue promotes growth of the patient's own skin cells rather than becoming incorporated into the recipient's skin as a true "graft." Further, it appears that a piece of fetal skin smaller than a postage stamp could be used to produce enough cells to treat hundreds of patients. "The results were sort of unexpected. . . . These constructs seem to work as a biological Band-Aid, promoting spontaneous healing of the patient," said Patrick Hohlfeld of University Hospital of Lausanne, who was one of the researchers. The study will appear in a future edition of the Lancet and was published online today. Cells grown from the foreskin of circumcised newborns and large pieces of skin removed from cadavers are sometimes used to cover burns and promote healing. The Swiss researchers were the first to use cells from a fetus -- a 14-week male whose mother gave permission at the time of abortion. Burns that destroy the outer skin layer -- the epidermis -- heal on their own. Ones that go deep into the second layer -- the dermis -- require skin grafts, patches of skin sliced off one part of the body, often the thigh, and transferred to the burned area. So-called third-degree burns that destroy the entire dermis and leave muscle or bone exposed also need grafts. Several burn experts said the technique sounded promising, but its usefulness is not yet proved. "I can't say whether it's a leap forward before we know how it compares with standard wound care," said Roger W. Yurt, head of the burn center at Weill Cornell Medical Center, in New York. "This is certainly work worth following with great eagerness. But in the absence of comparisons, it would be very difficult to assess the difference that the fetal cells bring," said Robert Sheridan, chief of burn medicine at Shriners Hospital for Children in Boston. Deciding which second-degree burns need skin grafts is often a matter of judgment. "Were they helping heal a burn that was going to heal on its own?" asked Gary Purdue, director of the burn center at Parkland Memorial Hospital in Dallas. "It's good if it helps do that, but it may be only an incremental advance." The Swiss researchers used a patch of fetal skin 1.5 inches square. They grew cells from it in tissue culture and let the cells spread out on sheets of a material called collagen, forming a kind of artificial skin. They cut that into pieces 3 1/2 by 5 inches and placed about four of them on 10-day-old burns in eight children. The burns were second- and third-degree, they said, and all would normally have undergone skin grafting. The fetal-cell material disappeared, but it was not incorporated into the regenerating skin. The scientists determined that by testing the genes in a piece of skin taken from a healed burn in a female patient. The skin contained no male cells, which it would have if it contained any of the fetal material. Skin cells secrete numerous chemical "growth factors" that cause progenitor skin cells to divide, spread out and attach to one another. Exactly how they differ from the cells of newborns or adults is uncertain. "We are very busy with the characterization of these cells and their byproducts," Hohlfeld said. A main problem with healed but heavily scarred burns is that they contract, limiting the motion of joints. Grafts frequently leave an uneven contour on the skin surface. Neither of these problems occurred in the eight children, according to the report. There was "total recovery of mobility, especially in hands and fingers." The patients have been followed for one to two years. There was some color change in some areas, but the overall appearance of the healed burns was good, Hohlfeld said. The team calculated that the small piece taken in this case could ultimately produce more than 2 million of the squares that were put on the burns. One fetus could theoretically provide material for hundreds or thousands of burn victims, although Hohlfeld said he suspected that would not remove some people's objections to the use of tissue from an aborted fetus.