"No other research group has published work on creating fully-viable, functional, three-dimensional bone substitutes from human iPS cells. These results bring us closer to achieving our ultimate goal, to develop the most promising treatments for patients," said de Peppo.
While severity varies, bone defects and injuries are currently treated with bone grafts, taken either from another part of the patient's body or a donor bone bank, or with synthetic substitutes. None of these permit complex reconstruction, and they may elicit immune rejection or fail to integrate with surrounding connective tissues. For trauma patients, suffering from shrapnel wounds or vehicular injury, these traditional treatments provide limited functional and cosmetic improvement.
After a comprehensive in vitro analysis of the generated bone, the NYSCF team assessed stability when transplanted in an animal model to address a major concern for iPS-based cell therapies. Undifferentiated iPS cells can form teratomas, a type of tumor. The iPS cell-derived bone substitutes were implanted under the skin of immunocompromised mice. After 12 weeks, the explanted constructs matured and showed no malignancies but complete maturation of bone tissue, while blood vessel cells began to integrate along the grafts. These results indicate the stability of the bone substitutes.
The scientists caution that although these results represent a major advance, further research is necessary before skin cell-derived bone grafts reach patients. Next steps include protocol optimization and the successful growth of blood vessels within the bone.
"Following from these findings, we will be able to create tailored bone grafts, on demand, for patients without any immune rejection issues," said Susan L. S
|Contact: David McKeon|
New York Stem Cell Foundation