What do stem cells, jaw bones, and salamanders have in common? They all have played a part in the recent advancements in regenerative medicine. As the Mayo Clinic points out, regenerative medicine itself isn’t new — forms of regenerative medicine such as the first bone marrow and solid-organ transplants were done decades ago. But advances in developmental and cell biology, immunology, and other fields have unlocked new opportunities to refine existing regenerative therapies and develop novel ones.
Mayo’s Center for Regenerative Medicine explains that regeneration involves delivering specific types of cells or cell products to diseased tissues or organs, where they will ultimately restore tissue and organ function. This can be done through cell-based therapy or by using cell products, such as growth factors. Bone marrow transplants are an example.
Stem cells are a key component of regenerative medicine, as they open the door to new clinical applications. Stem cells have the ability to develop — through a process called differentiation — into many different types of cells, such as skin cells, brain cells, lung cells and so on. Consequently, regenerative medicine holds the promise of definitive, affordable healthcare solutions that heal the body from within. Recent work done at Columbia University and the University of New South Wales (UNSW) in Australia is close to making this promise a reality.
Columbia College of Dental Medicine researchers have identified stem cells that can make new cartilage and repair damaged joints. The cells reside within the temporomandibular joint (TMJ), which articulates the jaw bone to the skull. When the stem cells were manipulated in animals with TMJ degeneration, the cells repaired cartilage in the joint.
“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,” said Mildred C. Embree, DMD, PhD, assistant professor of dental medicine at Columbia and the lead author of the study. Dr. Embree’s team, the TMJ Biology and Regenerative Medicine Lab, conducted the research with colleagues including Jeremy Mao, DDS, PhD, the Edwin S. Robinson Professor of Dentistry (in Orthopedic Surgery) at Columbia.
In a series of experiments, Dr. Embree and her colleagues isolated fibrocartilage stem cells (FCSCs) from the joint and showed that the cells can form cartilage and bone, both in the laboratory and when implanted into animals. Ultimately, Dr. Embree and her team say, the findings could lead to strategies for repairing fibrocartilage in other joints, including the knees and vertebral discs.
At UNSW in Australia, breakthrough research could make stem cell therapies capable of regenerating any human tissue damaged by injury, disease or aging available within a few years. The repair system, similar to the method used by salamanders to regenerate limbs, could be used to repair everything from spinal discs to bone fractures, and has the potential to transition current treatment approaches to regenerative medicine.
Study lead author, hematologist and UNSW Associate Professor John Pimanda, said the new technique reprograms bone and fat cells into induced multipotent stem cells (iMS). The technique has been successfully demonstrated in mice.
“This technique is ground-breaking because iMS cells regenerate multiple tissue types,” Associate Professor Pimanda said.
Prior to the UNSW research, no adult stem cells have been found that are capable of regenerating multiple tissue types. Typical adult stem cells are problematic, because they are tissue-specific. Embryonic stem cells can generate every type of cell in the human body, but they have challenges in therapeutic applications.
The UNSW study’s first author, Dr. Vashe Chandrakanthan, who developed the technology, said the new technique is an advance on other stem cell therapies being investigated. The reason is these other therapies have a number of deficiencies.
“Embryonic stem cells cannot be used to treat damaged tissues because of their tumor-forming capacity. The other problem when generating stem cells is the requirement to use viruses to transform cells into stem cells, which is clinically unacceptable,” explained Dr. Chandrakanthan.
“We believe we’ve overcome these issues with this new technique. We are currently assessing whether adult human fat cells reprogrammed into iMS cells can safely repair damaged tissue in mice, with human trials expected to begin in late 2017,” Associate Professor Pimanda said.
As the work at Columbia and UNSW show, advancements in stem cell technology can produce bone and cartilage as well as approximate how salamanders repair limbs. This work broadens the potential of regenerative medicine to treat joint and spine problems and accelerate recovery following complex surgeries where bones and joints are involved.
(Photo: Stem Cell, Pixabay)