Genetically Modified Regenerative Skin Graft Material Designed to Resist Infection

Stratatech’s StrataGraft® tissue is a second-generation human skin substitute that exhibits normal human skin structure and function. It is manufactured using the company’s proprietary NIKS® human keratinocytes, which were discovered at the University of Wisconsin. Keratinocytes are the cells that make up approximately 90 percent of the epidermis, the outer layer of human skin. NIKS® cells are a consistent source of pathogen-free, non-tumor-producing, long-lived adult progenitor cells. These cells faithfully reproduce normal human skin tissue architecture and barrier function when cultured appropriately. _StratatechCorp.

Regenerative medicine company Stratatech Corporation has developed a genetically tweaked living skin substitute for use in skin grafting. The genetic modifications of the living skin replacement makes it far more resistant to infection than currently available skin graft materials -- including autologous skin grafts.

The anti-infective capacity of Stratatech’s genetically-engineered tissue, which is being developed and commercialized by the company as ExpressGraft™ Enhance skin substitute through a worldwide exclusive license from the Wisconsin Alumni Research Foundation, or WARF, is produced by genetically engineering the elevated expression of a naturally-occurring antimicrobial host defense peptide called hCAP-18/LL-37. hCAP-18/LL-37 was selected because of its broad antimicrobial activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant S. aureus (MRSA), vancomycin-resistant E. faecalis (VRE) and other antibiotic-resistant hospital-acquired infections, as well as some fungi and viruses. The enhanced tissue possesses a full-thickness structure and barrier function similar to that of native human skin. The cell type used to generate the ExpressGraft™ tissue has been demonstrated to be non-tumor-producing and free from detectable pathogens, characteristics critical for cell-based, regenerative medicine therapies for patient use.

“Bacterial infection is a substantial cause of skin graft rejection and additional health care costs,” said Lynn Allen-Hoffmann, Ph.D., Stratatech’s founder, chief scientific officer and chief executive. “The potent anti-infective capability Stratatech has engineered in our living human skin substitute can be an important tool in improving skin-injury patient outcomes, and reducing the incidence and expense of hospital-acquired infections. We look forward to beginning the clinical evaluation of our antimicrobial skin substitute in the near term.

...Stratatech’s genetically-engineered skin substitute was generated using a non-viral vector, or carrier. The company believes it is the first time a virus-free approach has been used to genetically modify a living, cell-based tissue substitute. The data published in Molecular Therapy demonstrate that the modified tissue contained 139-fold more anti-infective proteins called host defense peptides than unmodified tissue in vitro. _BusinessWire

This is only the beginning of genetically improved, artificially grown bio-replacement materials. This skin replacement product from Stratatech should do well in the marketplace if it lives up to its promotion. But expect competing products that improve on the ExpressGraft's performance to emerge before long. This graft material does not perfectly reproduce the full, intricate layered structure of natural skin. But it is a good start.

Other more intricately structured grown replacement parts should follow on rather quickly. We are entering the age of regenerative medicine, when body parts and tissues will be grown in labs, rather than being donated by accident and crime victims. If these replacements can be designed to be tougher than the original parts being replaced, all the better.