The use of engineered tissue to repair bodily injuries has taken an important step forward as the transplant of engineered tissue containing major blood vessels had its first ever success. Such a transplant can repair severe abdominal muscle injury.
Prof. Shulamit Levenberg, of the faculty of biomedical engineering and the Russell Berrie Nanotechnology Institute of the Technion-Israel Institute of Technology in Haifa, headed the research team.
They have long worked on creating tissue on artificial scafford, and recently published their findings in the Proceedings of the National Academy of Sciences.
In the past, researchers had only managed to transplant engineered muscle tissue with small blood vessels.
But this medical breakthrough, on which the Technion holds a patent, may do away with the need for complex surgeries.
Levenberg said that they “engineered a muscle flap, bearing its own functional vascular pedicle for repair of a large soft tissue defect.
Technion scientists successfully replaced a full-thickness abdominal-wall defect using this engineered vascular muscle flap in a mouse.”
A pedicle is a part of a flat tissue that is left attached to the donor site and transposed to a new location. The pedicle is left intact to supply the tissue with nourishing blood.
In tissue reconstruction, there are two techniques to deal with the clinical challenges involved in the successful restoration of tissue defects, Levenberg said. In one of them, there is a graft of tissue transplanted to the damaged area. The blood vessels in the body penetrate the tissue and nourish it with a blood supply. The second technique involves a flap transplanted to the damaged region together with its own blood supply.
Flaps are used for treating injured areas that do not have an adequate blood supply and when blood vessels do not develop following transplantation. This occurs when damaged soft tissues do not close or there is exposed bone, tendons or cartilage, Levenberg said.
Tissue engineering constructs laboratory-grown tissue for transplantation.
In this study, the engineered tissue was a three-dimensional tissue constructed of a porous, biodegradable polymer scaffold embedded with endothelial cells, supporting fibroblasts and muscle cells (myoblasts).
The tissue was grown in the lab by Technion researchers and then implanted to the region around the femoral artery and veins in the thigh before being transferred as a flap.
The flap is the stage where tissues can be transferred with their own blood supply and are joined to the blood vessels in the region of transplant to repair large defects, such as in the abdominal wall region.
Grafts are effective for repairing small defects but ineffective at repairing severe injury. Consequently, the Technion’s new medical breakthrough is very important.
The study was performed in collaboration with Dr. Yulia Shandalov, who was Levenberg’s doctoral student during the time of the study, and Dr. Dana Egozi, from the department of plastic and re-constructive surgery at the Rambam Medical Center who was recently appointed director of the plastic surgery department at Rehovot’s Kaplan Medical Center.