Recovery from ligament injuries can be a long and painful process. Even with access to the best medical care, athletes can remain sidelined for many weeks or months and in some cases, individuals with ligament injuries never fully recover due to the formation of scar tissue, which can lead to weakness and further ligament damage.
New research could have hit on a new treatment for ligament injuries using exosomes. Exosomes are sacs of cell membrane which are used to transport proteins and genetic material between cells. Exosomes, in combination with exosome-educated macrophages (EEGs) – a type of white blood cell that removes dead cells and performs immune system functions – have been shown to stimulate other cells of the immune system and promote tissue healing, without the formation of scar tissue.
A team of researchers from UW-Madison had previously demonstrated that EEMs created by exposing CD14+ macrophages to mesenchymal stromal cell (MSC) derived exosomes helped to reduce inflammation in the Achilles tendon and improved tendon strength in mice. Treatment with MSCs alone was inferior to treatment with EEGs, which led to a new study to explore whether EEG treatment was effective for ligament injuries.
Exosome therapy was delivered to rats with medial collateral ligament (MCL) damage, with the researchers hypothesizing that the exosome therapy would accelerate ligament healing and reduce inflammation and scar formation, as was seen in their study on Achilles tendon injury in mice.
The study confirmed that exosome treatment on ligament injuries was also effective and accelerated healing, reduced information, and limited scar formation. The treatment reduced the M1/M2 macrophage ratio, increasing M2 macrophage availability, which are involved in wound healing and tissue repair.
Exosome therapy has now been shown to accelerate healing in tendon and ligament injuries, but the treatment could potentially be used for other scarring debilities, especially sports-related orthopedic conditions.
“As a cell therapy, EEMs will not proliferate or differentiate to undesirable cell types, which remains a concern for many stem cell therapies. Moreover, EEMs could be generated from a patient’s own monocytes using off-the-shelf exosomes, resulting in a faster and more facile process compared to autologous MSCs, “said Peiman Hematti, M.D., of the UW-Madison Department of Medicine and corresponding author of the paper. “Alternatively, exosome therapy could be a cell free, shelf-stable therapeutic to deliver biologically active components.”
You can read more about the study in the paper – Exosome‐educated macrophages and exosomes differentially improve ligament healing – which was recently published in the journal Stem Cells. DOI: 10.1002/stem.3291