Pitt, McGowan Institute Advance Bioscaffold Knowledge

Researchers from the University of Pittsburgh “Pitt” School of Medicine and the McGowan Institute for Regenerative Medicine have found a mechanism by which bioscaffolds used in regenerative medicine influence cellular behavior.

“Bioscaffolds fulfill an unmet medical need, and have already changed the lives of millions of people, ” said lead study investigator Stephen Badylak, D.V.M., M.D., Ph.D., professor of surgery at Pitt and deputy director of the McGowan Institute, a joint effort of Pitt and UPMC.

According to the July 27, 2016 news release, “Researchers know that ECM [extracellular matrix] is able to instruct the human body to replace injured or missing tissue, but exactly how the ECM material influences cells to cause functional tissue regrowth has remained a fundamental unanswered question in the field of regenerative medicine. In the new study, Dr. Badylak and his team showed that cellular communication occurs using nanovesicles, extremely tiny fluid-filled sacs that bud off from a cell’s outer surface and allow cells to communicate by transferring proteins, DNA and other “cargo” from one cell to another.”

“We always thought exosomes are free floating, but recently wondered if they are also present in the solid ECM and might facilitate the cellular communication that is critical to regenerative processes, ” Dr. Badylak said.

“To explore this possibility, researchers used specialized proteins to break up the ECM, similar to the process that occurs when a bioscaffold becomes incorporated into the recipient’s tissue, ” says the news release. “The research team then exposed two different cell types—immune cells and neuronal stem cells—to isolated matrix bound vesicles, finding that they caused both cell types to mimic their normal regrowth behaviors.”

“Sure enough, we found that vesicles are embedded within the ECM. In fact, these bioscaffolds are loaded with these vesicles, ” Dr. Badylak said. “This study showed us that the matrix bound vesicles are clearly active, can influence cellular behavior and are possibly the primary mechanism by which bioscaffolds cause tissue regrowth in the body.”

Dr. Badylak told OTW, “Biologic scaffold materials elicit a patient response that is markedly different than polypropylene mesh. The mechanisms by which infection resistance, angiogenesis, and constructive remodeling occur have been largely ignored. The stimulus for the present study was an interest in understanding the effects of extracellular matrix (bioscaffolds) upon cell behavior.”

“Orthopedic, trauma, and reconstructive surgeons now have at least a partial explanation for the constructive remodeling that occurs in patients for which these materials are indicated.”