Chance Discovery of "Immortal Skin" Holds Medical Promise
From a routine study of the life span of human skin cells, a University of Wisconsin (UW)-Madison research project gave rise to an astonishing accident: a line of skin cells that simply would not die.
The research team witnessed a rare spontaneous mutation when a small cluster of cells in a petri dish continued to actively divide. The scientists continued to grow this unique cell line over the course of a year without the cells showing any signs of slowing down. Today, this effort has developed into a patented product, a full-fledged commercial venture, and a series of new medical research pursuits.
Stratatech, a UW-Madison spin-off company, is actively pursuing a number of markets for its patented "immortal human skin." Clinical applications are several years away, but the company recently received promising news: Its first animal tests confirmed that the novel skin will cover and heal superficial wounds. Most important, Lynn Allen-Hoffmann, PhD, a professor of pathology in the UW-Madison Medical School and managing director of Stratatech, says the cells grow into distinct stratified layers to become essentially no different from normal skin.
The unique tissue is composed entirely of keratinocyte cells. The cells can be genetically engineered to fit different medical or research needs, according to Dr Allen-Hoffmann.
A key milestone remains in proving the tissue would not be rejected by human patients. Stratatech has plans to move quickly toward possible medical uses, with clinical trials and work with regulatory agencies leading to initial human trials by 2002.
Composite Cultured Skin
Ortec International, New York, NY, has released a preliminary analysis of its pilot study of Composite Cultured Skin (CCS) in the treatment of diabetic ulcers. At 12 weeks, 56% of patients (5 of 9) treated with CCS achieved 100% wound closure, compared with 29% of patients (2 of 7) in the control group.
These data are based on planimetric analysis, a method in which computer scans of the wound area are evaluated over time for the percentage of wound closure. Both treatment groups received standardized wound care. The study protocol allows for patients in the CCS-treated group to receive a single application of CCS weekly for up to 6 weeks. The patients in this group received an average of 4 CCS applications within the 12-week time period.
The study is being conducted at 8 centers; a total of 32 patients are enrolled. All patients in the study are subject to a prescreening period, during which standard wound care is administered. If a patient's ulcer heals more than 30% during this screening period, the patient is not included in the study. In addition, the ulcer must be a minimum of 1 cm after completion of the screening period in order for the patient to be enrolled in the study.
Ortec has received permission from the Food and Drug Administration (FDA) to begin a pivotal clinical trial using a cryopreserved version of CCS to treat venous ulcers. The trial is expected to include up to 200 patients followed for 3 months after treatment and will involve up to 30 clinical centers throughout the United States. Completion of patient enrollment is expected by July 2001.
In August 2000, Ortec submitted to the FDA a final report on the interim results of its venous ulcer pilot study, which showed that CCS continued to demonstrate superiority over the standard of care in the treatment of hard-to-heal venous ulcers. In particular, the report showed that at 8 weeks, 47.1% of the overall CCS-treated group achieved 100% wound closure, compared with 26.3% for the control group. In addition, the percentage of the CCS-treated group achieving 100% wound closure increased to 52.9% at 12 weeks, whereas the control group remained constant at 26.3%.