Osteoarthritis is a disease in which joint cartilage degenerates and the bony edges of the joint rub against each other. The disease causes pain and disability in the affected joint. There is no cure for osteoarthritis, except perhaps for artificial joint replacement surgery. Patients who are not candidates for surgery must get by with pain medications, braces, and physical therapy.
Given that osteoarthritis affects millions of people and there are limited options for long-term treatments other than major surgery, researchers are working very hard to find additional ways to manage this condition. One of the most exciting developments has been in the field of regenerative medicine, also known as stem cell therapy.
Stem cells injected into arthritic knees, for example, may help reduce the patient’s pain, protect cartilage, or even slightly heal the joint damage. Many patients feel relief and see improvements from just one therapy. Some with more advanced conditions may require a more maintenance plan. But today, researchers are now focused on the mesenchymal stem cell secretome.
What is a mesenchymal stem cell secretome? A mesenchymal stem cell secretome is the total of all of the molecules that mesenchymal stem cells secrete or release to support, restore, and regenerate tissue. The molecules released from mesenchymal stem cells, mostly through stem cell exosomes, exert many powerful benefits on joints.
From laboratory experiments in animals, we know the mesenchymal stem cell secretome is anti-apoptotic, which means it protects joint cells from committing programmed cell suicide. The secretome is also anti-fibrotic, and fibrosis can be damaging to joints and make them stiff. The secretome is pro-chondrogenic and pro-angiogenic, which means it helps build cartilage and blood vessels, respectively.
Lastly, the mesenchymal stem cell secretome modulates the immune system. While rheumatoid arthritis is considered the major inflammatory joint disease, inflammation also takes place in osteoarthritis. So, the mesenchymal stem cell secretome can modulate the immune system and reduce joint inflammation.
The main way that patients can reap the potential benefit of the mesenchymal stem cell secretome is through exosomes. Exosomes are small particles that contain most of the substances released in the secretome. Exosome treatment does not require stem cell infusions, and many, many more exosomes can be administered during a treatment session than stem cells, mainly because they are physically much smaller.
The concept of mesenchymal stem cell secretome is rather new, but it is a powerful concept in the treatment of osteoarthritis. As more human clinical studies are done, we should be able to unlock the power of the secretome for patients with osteoarthritis.
Reference: Mancuso P, Raman S, Glynn A, Barry F, Murphy JM. Mesenchymal Stem Cell Therapy for Osteoarthritis: The Critical Role of the Cell Secretome. Front Bioeng Biotechnol. 2019;7:9. Published 2019 Jan 29. doi:10.3389/fbioe.2019.00009