Alpha-2-macroglobulin (A2M) is a plasma protein found in the blood. Its role is to inhibit enzymes that are known to degrade cartilage. Degradation of cartilage leads to osteoarthritis.

By inhibiting these enzymes, alpha-2-macroglobulin can prevent the breakdown of cartilage. At a high concentration, this stops the progression of osteoarthritis and improves joint function which leads to decreased pain.

In combination with platelet-rich plasma or bone marrow concentrate, A2M can assist the healing response of regenerative medicine.

Alpha-2-macroglobulin can be concentrated from the remaining plasma or acellular bone marrow after centrifugation of the blood or bone marrow aspirate, respectively. It is then injected into the joint being treated under ultrasound guidance.