Philadelphia -- Ellen Heber-Katz, Ph.D., a professor and immunologist at The Wistar Institute, has been invited to speak at the 165th national meeting of the American Association for the Advancement of Science (AAAS). Her presentation on The Genetics of Tissue Repair and Regeneration in Mice will be one of only seven science topical lectures designed to highlight emerging and innovative research. Prior to her presentation, Dr. Heber-Katz will participate in a 50-minute news briefing with reporters.
The AAS meeting and Science Innovation Exposition will be held from February 12-17, 1998 in Philadelphia -- where its first meeting was held 150 years ago. It is the scientific community's most visible forum for increasing the public's understanding of science.
Dr. Heber-Katz's presentation will focus on the mouse she and her research team discovered, which is the first potentially useful model for studying epimorphic (limb) regeneration in humans.
Until now, it has been possible to study regeneration only in amphibians, which are biologically, genetically and immunologically different from mammals. "Despite those limitations," says Dr. Heber-Katz, "there has been impressive work done by amphibian biologists. They laid out the basic biological road map for the study of regeneration."
Dr. Heber-Katz's discovery of the healer mouse occurred five years ago, when her laboratory was using different autoimmune mouse models to study multiple sclerosis. As a way of painlessly and permanently separating one group of immunized mice from the others, Dr. Heber-Katz's staff pierced their ears, a standard laboratory method for identifying groups. Within weeks, however, the holes had closed. The researchers, thinking they had made a mistake, re-pierced their ears. Again, the holes closed with full replacement of the epidermis, dermis and cartilage, and with no evidence of scarring.
"At first" explains Dr. Heber-Katz, "it wasn't clear if we had a model for studying wound repair or regeneration, which is a rare form of wound healing in mammals. Since then, however, our findings have made it clear that this is classic epimorphic regeneration. These mice have characteristics, including tail regrowth and rapid liver regeneration, similar to those seen in amphibian tissue regeneration."
By crossing mice that are healers with those that are not, Dr. Heber-Katz and her research team are collecting valuable information about the genes involved in regeneration. Thus far, they have identified seven chromosomal regions and isolated several gene products that differ between healers and non-healers.
They also have found that, as the healer mice age, they do not regenerate as quickly or as well. Yet, when the researchers use a specific antibody to deplete a subset of T-cells, which are the cells responsible for cell-mediated immunity, the mice heal perfectly.
"It is intriguing to speculate," says Dr. Heber-Katz, "that repair of wounds became dominant in mammals with the development of a complex immune system, which was there to protect against tumors. It is known that molecules expressed in regenerating tissue are also expressed in tumors and, for that matter, during mammalian development. In fact, fetal wound healing is scarless and occurs before the development of the T-cell compartment of the immune system."
Dr. Heber-Katz expects her findings may ultimately make it possible to promote organ replacement, enhance the healing of chronic wounds, burns and spinal cord injuries, and control tissue growth. Her work is being funded in part by the National Institutes of Health.
The Wistar Institute, established in 1892, was the first independent medical research facility in the United States. For more than 100 years, Wistar scientists have been making history and improving world health through their development of vaccines against diseases that include rabies, German measles, infantile gastroenteritis (rotavirus), and cytomegalovirus; discovery of molecules like interleukin-12, which are helping the immune system fight bacteria, parasites, viruses and cancer; and location of genes that contribute to the development of diseases like breast, lung and prostate cancer. Wistar is a National Cancer Institute Cancer Center.