"This is the first demonstration of in vivo gene therapy where the genes have made a large extracellular molecular structure that you can actually see with a microscope," says David Woodley, M.D., professor and chief of dermatology at the Keck School and the principal investigator on this study. Scientists from Shriners Hospital for Children in Portland, Oregon, Northwestern University in Chicago, and Xgene Corporation in San Carlos, California, also participated in the study.
Woodley was helped by his previous efforts in the field: In 1992, he and some of his colleagues became the first team to clone the human gene for type VII collagen, which is one of the key components of the skin's extracellular matrix. Collagen makes up the tendrils and fibrils that provide a cushion for the skin's cells to rest upon; type VII collagen, in particular, is critical to the creation of the skin's so-called anchoring fibrils.
"Anchoring fibrils," Woodley explains, "are like connective tissue staples--they staple the epidermal layer of the skin to the dermis." Without these fibrils, the layers of the skin can separate like layers of pastry, blistering and sloughing off at the slightest insult or injury.
And that is why people without type VII collagen develop dystrophic epidermolysis bullosa, in which blisters form all over the body, leaving behind permanent scars.
"By the time people with epidermolysis bullosa are 20
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Contact: Jon Weiner
jonweine@usc.edu
323-442-2830
University of Southern California
23-Dec-2002