Injectable substance made with proteins enables tissue to grow new blood vessels

Newswise — SAN FRANCISCO: A biologically engineered gel designed to improve the survival of bioengineered organs and other tissues has shown promise in early laboratory testing, according to researchers at the Wake Forest Institute for Regenerative Medicine, Winston-Salem, NC. They presented their findings at the 2011 Annual Clinical Congress of the American College of Surgeons.

Tamer Aboushwareb, MD, PhD, assistant professor of urology at the institute, explained that the gel enables regenerated tissues to grow new blood vessels in the human body. The gel is collagen-based and mixed with fibrin, a naturally occurring protein in the body. This compound can be loaded with and release vascular endothelial growth factor (VEGF) over time. VEGF is a cell protein that stimulates the growth of new blood vessels during tissue development. The body also releases this protein naturally to grow new blood vessels after an injury or exercise, or to bypass blocked arteries.

The Wake Forest researchers formulated the gel in such a way that it can be injected into the body and control the release of VEGF for up to 12 days. Their goal is to develop a gel that can release VEGF over a longer period, Dr. Aboushwareb said.

The investigators at Wake Forest Institute for Regenerative Medicine have been collaborating on a host of projects using the body’s cells to grow new tissues for damaged organs. One of the co-investigators of the study presented at the American College of Surgeons meeting, Anthony Atala, MD, FACS, has been the renown lead investigator of a team that has grown bladder cells.

However, Dr. Aboushwareb said that among the ongoing problems with placing bioengineered tissues in the body is getting the tissue to grow new blood vessels. “If we can put these gels with these factors on, for example, the bladder, we would then be able to attract vascular tissues to the bladder very early on and greatly improve the survival of this tissue,” Dr. Aboushwareb said. “This gel is an enabling technology that will allow us to enhance the tissues that we make.”

This gel promises to move regenerative medicine to the next level, according to Dr. Aboushwareb. “The field is in prime time right now to be able to place live tissues that need vascularization into patients,” he said. “With this gel and other technologies, we’re giving the entire field a push toward a better construct for tissue replacement.”

The next step is for the investigators to develop a gel with an even slower release of VEGF. “If we can get it to a release time of 28 days or even 58 days, then we’re giving the implanted tissue a much greater chance of allowing the vascular tissue to grow into it,” Dr. Aboushwareb explained. Further down the road the gel may be incorporated into the engineered tissues that doctors will implant.

According to Dr. Aboushwareb, the Wake Forest investigators have started using the gel in small animal trials, the precursor to larger animal trials and, eventually hope to move to human trials.

Study investigators were led by Young Min Ju, PhD. Other investigators are Zhan Wang, PhD; Shaida Moghaddassi, PhD; Anthony Atala, MD, FACS; Shay Soker, PhD; James J. Yoo, MD, FACS; and San Jin Lee, PhD.

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2011 Annual Clinical Congress of the American College of Surgeons