The neurons originated in an embryonal cancer cell line that was treated with retinoic acid in a process to differentiate the cells and to render them benign.
Significantly, when the human neuronal cells were frozen and then thawed prior to transplantation, they proved equally as effective as fresh cells in easing the symptoms of stroke in rats. Furthermore, the tumor-derived cells did not revert to abnormal tissue growth after transplantation into the brains of rats.
"This suggests that human neuronal cell transplantation may be a useful alternative to fetal tissue in treating strokes and other neurodegenerative disorders," says Paul R. Sanberg, PhD, professor and director of neurosurgical research at USF and senior author on the study. "The grafts' resistance to the effects of cryopreservation is rather remarkable. Frozen fetal brain cells do not survive long after they are thawed."
Experimental transplantation using fetal brain cells has been successful in a small number of patients with Parkinson's disease, but the potential for widespread use of fetal tissue is limited, partly because of difficulties associated with preservation.
"The clinical potential is that a readily available supply of cryopreserved human neuronal cells, made under controlled conditions and stored frozen, could be used as replacement therapy to reverse the deficits of stroke," notes Virginia M.-Y. Lee, PhD, a professor of pathology and laboratory medicine at Penn and a coauthor on the study.