Tissue pushes healthy skin invasion

CORNELL (US) — Manufactured tissue grafts could benefit victims of traumatic injuries by encouraging healthy skin to move into wounded areas, reducing the need for surgery.

Composed of experimental tissue scaffolds about the size of a dime with the consistency of tofu, the biomaterials are made of a material called type 1 collagen, often used in surgeries and other biomedical applications.

“The challenge was how to promote vascular growth and to keep this newly forming tissue alive and healthy as it heals and becomes integrated into the host,” says Abraham Stroock, associate professor of chemical and biomolecular engineering at Cornell University.

The grafts promote the ingrowth of a vascular system—the network of vessels that carry blood and circulate fluid through the body—to the wounded area by providing a template for growth of both the tissue (dermis, the deepest layer of skin), and the vessels. Type I collagen is biocompatible and contains no living cells itself, reducing concerns about immune system response and rejection of the template.

A key finding of the study, published in the journal Biomaterials, is that the healing process responds strongly to the geometry of the microchannels within the collagen. Healthy tissue and vessels can be guided to grow toward the wound in an organized and rapid manner.

Dermal templates are not new; and some are widely used for burns and other deep wounds, fall short in their ability to encourage growth of healthy tissue.

“They can take a long time to incorporate into the person you’re putting them in,” says Jason A. Spector, assistant professor of surgery at Weill Cornell Medical College.

“When you’re putting a piece of material on a patient and the wound is acellular, it has a big risk for infection and requires lots of dressing changes and care. Ideally you want to have a product or material that gets vascularized very rapidly.”

Patients often need significant reconstructive surgery to repair injuries with exposed vital structures like bone, tendon, or orthopedic hardware. The experimental templates are specifically designed to improve vascularization over these “barren” areas, perhaps one day eliminating the need for such invasive surgeries and reducing the patient’s discomfort and healing time.

Eventually, the scientists may try to improve their tissue grafts by, for example, reinforcing them with polymer meshes that could also act as a wound covering.

The work was supported by the Morgan Fund for Tissue Engineering and the New York State Office of Science, Technology and Academic Research.

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