Tissue Engineering and Regenerative Medicine Group
In the reconstructive treatment of anterior cruciate ligament (ACL) rupture of the knee, the autologous tendon is used as a prosthetic material. However, the use of autologous tendons is highly invasive because the tendons are harvested from the patient's leg, and the loss of muscle strength in the leg after surgery has been an issue. To solve this problem, we are developing decellularized tissues that do not require autologous tendon harvesting, do not cause rejection after implantation, and become autologous through cell infiltration.
In our decellularization process, tissues are mounted in a circuit in which a surfactant solution is pulsatingly circulated and then irradiated with microwaves to remove the cells. We have succeeded in eliminating more than 99% of DNA from tissues that have been continuously irradiated with microwaves for 24 hours.
Elucidation of tissue remodeling
Decellularized tissues after ACL reconstruction are remodeled in vivo, and it has been revealed that the strength of the decellularized tissues increases after implantation and that the type of collagen and the thickness of fibers that compose the decellularized tissues become similar to those of ligaments, a phenomenon called "ligamentization". To elucidate the mechanism of ligamentization, we are performing ACL reconstruction studies in large animals and evaluating the mechanical properties and histology after 13 weeks or 52 weeks of implantation.