This gets a bit complicated: In mice, scientists used adult stem cells to prevent embryonic stem cells used to treat spinal cord injury from forming tumors. From the story:
Transplanted embryonic stem cells are recognized as a potential treatment for patients suffering from the effects of spinal cord injury (SCI). However, in studies using embryonic stem cells transplanted into SCI laboratory animals, a serious drawback has been the development of tumors following transplantation.
Publishing in the current issue of Cell Transplantation (Vol. 18 No.1), a team of Japanese researchers describe their study that demonstrates a way to eliminate the problem of tumor growth by co-transplanting bone marrow stem cells (BMSCs) along with embryonic stem cells. “Our study results suggest that co-transplanting BMSCs induce undifferentiated embryonic stem cells to differentiate into a neuronal lineage by neurotrophic factor production, resulting in suppression of tumor formation in SCI model mice,” said corresponding author Dr. Masahide Yoshikawa of the Nara Medical University. “…
A control group of mice that only received ES cells developed tumors at the grafted site and their behavioral improvement ceased after three weeks. No tumors developed in the co-transplantation group and behavioral improvement continued over the five-week study. To date, no effective medical therapy has been available for SCI patients. While ES cells have been thought to represent a potential resource for therapy, the hurdle of tumor formation has impeded efforts.
Unmentioned in the article is that adult stem cells in human trials have restored sensation to spinal cord injury patients with both paraplegia and quadriplegia. But never mind, this could move the future of direct ESC therapies forward.