Dr Mildred Embree and colleagues of Columbia College of Dental Medicine have recently discovered and demonstrated that autologous stem cells of an individual — already present in their joints – could be manipulated to manufacture new cartilage tissue and help repair damaged jawbone.
These stem cells are located within the temporomandibular joint (TMJ), which helps connect the jaw bone to the skull. When the stem cells were bioengineered in animals with TMJ degeneration, the cells were able to repair cartilage in the joint. A single stem cell injected in a mouse automatically started manufacturing cartilage and bone and even began to form a bone marrow niche. This discovery has thrilled medical researchers.
Dr Mildred C Embree, DMD, PhD, the lead author of the study and an assistant professor of dental medicine at Columbia, said regarding the findings, “This is very exciting for the field because patients who have problems with their jaws and TMJs are very limited in terms of clinical treatments available.”
According to the National Institutes of Health, up to 10 million people in the US, out of whom most are women, suffer from TMJ disorders. TMJ disorders are a type of temporomandibular disorder that can cause pain in the jaw and muscles that control jaw movement. It is often difficult to exactly pinpoint the cause of the pain, since TMJ disorders can be due to a variety of factors such as arthritis, genes and even injury to the jaw.
Before this latest groundbreaking discovery, treatment options for TMJ disorders were limited to either surgery or palliative care. Palliative care deals with the disease symptoms but can’t actually regenerate the damaged tissue. This discovery will change that since it will allow manufacturing of new tissue.
Cartilage helps to soften the joints and allows them to move smoothly. The type of cartilage within the TMJ is known as fibrocartilage, which is also present in the knee meniscus and in the discs between the vertebrae. Because fibrocartilage cannot be regenerated or even repaired, injury or disease that damages this tissue can lead to permanent disability.
Scientists, researchers and physicians have been trying to improve stem cell research and use them more frequently, given their massive potential. They are focusing on immature cells that can generate into various types of tissue. Since there are numerous difficulties in transplanting donor stem cells, such as the possibility of recipient’s immune system rejecting them, researchers are trying to figure out ways to use stem cells already residing in the body.
Dr Mao, the co-director of the Center for Craniofacial Regeneration at Columbia, said that there are quite varied possibilities of these findings, including clinical therapies. These findings point out that molecular signals that control stem cells can have therapeutic applications for cartilage and bone regeneration.
Dr Embree, Dr Mao and their colleagues have conducted a series of experiments in which they isolated fibrocartilage stem cells (FCSCs) from the joint and showed that the cells can develop cartilage and bone, both in the laboratory and when implanted into animals.
Dr Embree’s team also identified a molecular signal, Wnt, that reduces the amount of FCSCs produced by the body and leads to cartilage degeneration. They reached the conclusion that injecting a Wnt-blocking molecule called sclerostin into degenerated TMJs in animals enhanced cartilage growth and helped the joint heal.
Dr Embree and her team are now looking for other chemical compounds that can be used to prevent Wnt signals from generating and will enable FCSC growth. Her focus now lies on discovering a drug that could be injected right into the joint without causing and adverse reactions or harmful effects.
The Dr further went on to say that children suffering from juvenile idiopathic arthritis can have impaired jaw growth which cannot be effectively treated with the current lineup of drugs. Since the TMJ is the center at which most of the jaw growth takes place, the new research can produce new techniques and ideas for treating these children and shine a better light on how the jaw grows and develops.
While orthodontists currently have to rely on outdated techniques and technology like headgear to modify jaw growth, she added, the findings could lead to a better solution involving controllable growth at the cellular level.
So Who Can Benefit From This Discovery?
Certainly athletes, especially boxers and MMA fighters, will be happy to hear this news, since they frequently suffer from these kind of injuries that can certainly end their careers and even lives in extreme cases.
Stem cell research has gained a lot of momentum over the past few years. In a previous study, scientists from Stanford University School of Medicine discovered that the heart muscle cells made from human induced pluripotent stem cells (hiPSCs) under laboratory settings reflect the gene expression pattern of the donor heart tissues.
The study found that genetic expression of particular cardiac proteins involved in metabolic and stress pathways leads the variation of drug response amongst individuals. That study had the potential of leading to a new treatment technique for cardiovascular diseases using stem cells.
Dr Embree and her team acknowledged that the findings of their study could lead to strategies for repairing fibrocartilage in other joints of the body as well, including knees and vertebral discs. “Those types of cartilage have different cellular constituents, so we would have to really investigate the molecular underpinnings regarding how these cells are regulated,” the researcher said.