Nov. 20, 2000 -- Skin cells that never say die may soon give rise to a line of off-the-shelf human skin grafts that can be used to cover nonhealing wounds or burns involving large areas of the body, say researchers.
While studying the normal life span of human skin cells in the laboratory in 1996, Lynn Allen-Hoffman, PhD, and colleagues at the University of Wisconsin, in Madison, watched in astonishment as an apparently spontaneous change in the genetic make-up of a cell gave birth to a line of cells which kept dividing for more than a year, without so much as a coffee break. At last report, the cells were still growing, with no signs of the aging and eventual death that usually occur both in the laboratory and in the human body.
The discovery may have been by chance, but it's no accident that the immortal cell line has been patented and forms the basis of a start-up biotechnology company. "There are a lot of opportunities dovetailing out of this single basic discovery that are very exciting," says Allen-Hoffman, professor of pathology at University of Wisconsin, in a written statement. "It would be a career dream come true to develop some kind of off-the-shelf product that would be available to doctors."
Other biotechnology companies already have skin-graft products derived from human skin cells on the market. Like the immortal cells, the cells in those grafts are taken from human foreskins discarded after circumcisions of the penis.
The cells used by the Wisconsin researchers have been shown to cover and allow healing of minor wounds in animals and, according to Allen-Hoffman, grow into distinct layers much like normal human skin. "These cells proved to be incredibly normal," she says.
Although the cells are theoretically capable of endless growth, which is one of the hallmarks of cancer cells, they did not produce tumors when implanted into mice, and they maintained the features of normal skin cells.
But immortality may not be all it's cracked up to be. There are many hurdles that need to be overcome before a practical, long-lasting and easy-to-use replacement skin product can be developed, cautions one wound-healing researcher.
"The problem there is that it's a [foreign tissue] graft -- although it's human skin, it will get rejected eventually. But in a lot of cases it doesn't really matter, because you're just using as it as a wound covering and you only need it to be there for a few weeks," Martin L. Yarmush, MD, PhD, professor of surgery at Harvard Medical School, tells WebMD. "I don't know if it solves any of the real problems in the field, because some of the surgeons complain about the [cultured skin] products themselves," says Yarmush.
The researchers foresee other uses for their lab-grown skin, including testing of the safety of cosmetics without the need for animal studies, and a way for evaluating the effects of various drugs on some skin conditions. Allen-Hoffman and her colleagues currently are using the lab-grown skin to study skin cancer and the effects of environmental toxins, such as dioxin.