Aperion Biologics has taken major steps towards making xenografts a competitive alternative for use in the nearly one million ACL reconstruction surgeries performed globally every year. A xenograft is tissue taken from one species and transplanted into another, however they are not commonly used since there is a high risk that the transplant will be rejected by the human immune system and lead to serious complications.
A graft that is safe, effective, and readily available is the ‘triple threat’ of transplant tissue that has yet to be achieved by a single option. An autograft, which relocates tissue from elsewhere in the patient’s body, is safe and readily available but is not as effective as other options since the tissue is not ACL tissue. Additional hardware may be required for fixation and the patient’s recovery may be slowed since it is not a perfect substitution. An allograft, which transplants tissue from human cadavers, is safe and effective but very limited in supply. Typical xenografts are effective and available, but very risky due to the immunogenicity barrier.
Aperion has targeted this xenograft hurdle. They have created a proprietary treatment method for porcine ACL tissue that will prevent the tissue from triggering a rejection response, without disrupting its ligament structure and mechanical properties. This method, called the Z-Process, includes a sterilization wash and subsequent treatments that target the identified culprits of rejection. One treatment exposes the tissue to enzymes that will digest antigens with an α-galactosyl epitope, since, despite their abundance in non-primate mammals, primates have developed the antibodies to reject these antigens. A second treatment exposes it to molecules that will bind to the ends of the surface carbohydrate chains of the tissue, effectively making these chains “invisible” to immune system cells that would otherwise bind to them and identify them as foreign. Once the xenograft tissue is implanted, it becomes the scaffold to aid in a patient’s natural regeneration of the damaged ACL.
The Z-lig tendon is already CE-marked and available in Europe and South Africa. Aperion is currently conducting a clinical trial in the US, and if successful, it’s easy to imagine many kinds of xenografts that will become common practice in procedures ranging from bone grafts to heart valve replacements.
Here’s a TED talk on the subject by the company’s chairman Kevin Stone:
Source: Aperion Biologics…