A group of Japanese researchers announced they have begun a clinical trial of a medical material derived from cow tendons to be used in people who need to have the anterior cruciate ligaments (ACLs) in their knees reconstructed.
An ACL injury, in which one of the ligaments that stabilize the knee joint is torn or sprained, is a common sports injury. The ligament is torn most often during sports that involve sudden jumps and turns, such as basketball, soccer and baseball.
The researchers ¡ª led by Kiyotaka Iwasaki, a professor at Waseda University, as well as others from Tokyo Women¡¯s Medical University ¡ªhave confirmed the safety of the material derived from cow tendons in surgeries on seven patients. They have recently begun a randomized controlled study at six institutions across Japan, where 57 patients needing ACL reconstruction surgery are broken into one group who receives the experimental material and one group who has their own tendons from other areas transplanted. The study aims to establish the efficacy and long-term safety of transplanting the cow-derived material.
Currently, tendons taken from the patient¡¯s own hamstring or knee are transplanted to reconstruct the torn ligament. But removing these tendons can cause pain where the tissue is removed and may also reduce muscle strength.
While cow tendons have the thickness and strength that make them an ideal ligament material, they can trigger an immune response such as inflammation if transplanted directly.
The researchers say they overcame the challenge through a unique ¡°decellularization¡± technology, where they remove the cellular components that cause immune reactions without damaging the tendon tissue. For this, they use a pulsating pump to let a solution that breaks down cells penetrate deep into the tissue, while irradiating it with microwaves to speed up the cell removal process.
They also established a process that enables the decellularized tissue to be freeze-dried and sterilized while retaining its mechanical strength, Iwasaki said.
¡°Decellularized membrane-like tissues about 1 millimeter thick derived from pigs are already used as clinical products in the U.S.,¡± Iwasaki said. ¡°But no commercial products that use thick animal-derived tissues such as ours, which are 8 mm thick, currently exist.¡±
Iwasaki added that, along with CoreTissue BioEngineering, a startup he founded in 2016, the researchers are aiming to obtain regulatory approval for the device in Japan in 2029, and they are preparing for a clinical trial in the U.S. as well.
In the U.S., , experts say. In Japan, some 20,000 to 30,000 people ¡ª typically high school or college athletes ¡ª suffer the injury, out of which about 15,000 undergo knee reconstruction surgery.
Iwasaki hopes to apply the technology to the reconstruction of other ligaments in the knee, as well as in the ankle and inner elbow. This includes Tommy John surgery, which many Major League Baseball players, including Shohei Ohtani and Yu Darvish, are known to have undergone.
The material might even prove helpful in the treatment of rotator cuff tears, which afflict 25% of people in their 60s and 50% of people in their 70s, the researchers said.
¡°The newly developed regenerative ligament is not a material to replace a torn ligament, but it is something that helps patients¡¯ cells grow into it and gradually replace it with their own ligament,¡± Iwasaki said. ¡°Competitive athletes and regular people alike would find it invaluable if they could (quickly) return to sports, work and their normal daily lives.¡±
With your current subscription plan you can comment on stories. However, before writing your first comment, please create a display name in the Profile section of your subscriber account page.