The company’s second-generation product line, called ExpressGraft™, consists of skin tissues that are genetically engineered to express and secrete factors to fight bacterial infections, promote blood flow, or reduce scarring during healing. The first product will target chronic diabetic skin ulcers, which become infected and lead to impaired wound healing and amputation.
Chronic diabetic skin ulcers are typically treated with antibiotics, but the strains of bacteria involved often grow resistant. Stratatech is tackling the problem with human tissues that secrete biologically active antimicrobial peptides designed to stimulate the body’s innate immune system. The Department of Defense is also funding research at Stratatech on a field-ready antimicrobial wound dressing. A ready-to-use antimicrobial skin substitute is needed to close wounds and reduce infections on battlefields.
Another type of engineered skin is designed to heal chronic skin wounds by promoting angiogenesis. Factors that activate the network of genes that promote vascularization have been programmed into NIKS cells with nonviral vectors. The neuropathy associated with diabetes is addressed in a different engineered cell line that stimulates nerve function in the extremities. Patients with skin ulcers often experience tissue breakdown because they lose nerve function and cannot feel damage occurring to the skin.
Stratatech scientists have developed another tissue line that expresses a proteinase inhibitor. Proteolytic activity naturally increases as skin ages, contributing to tissue breakdown and poor wound healing in the elderly. No biological therapies exist that target the underlying proteolytic nature of chronic wounds. Stratatech plans to start clinical trials of some of these new products in 2009.
In addition to treating patients, StrataTech’s technology platform can be used to screen consumer products. The company sells StrataTest™ skin tissue, a miniaturized version of StrataGraft, to help researchers test potential drug compounds or consumer products like cosmetics. “It provides a biologically relevant, in vitro assay,” explains Dr. Allen-Hoffmann.
Due to a shortage of cultured human cells for pharmaceutical and cosmetic testing, researchers must rely on animal testing or cell lines that poorly duplicate actual human-skin performance. This raises concerns about ethics, accuracy, cost, and reproducibility. “There’s a real need for reliable alternatives to animal testing,” she adds.