Scientists Use Adult Stem Cells to Fix Tumor Problems of Embryonic Stem Cells
by Steven Ertelt
May 12, 2009
Tokyo, Japan (LifeNews.com) — Embryonic stem cells have never helped human patients in part because they produce tumors when injected as treatments in animal research. Now, Japanese scientists are relying on the more ethical adult stem cells to curb the problems associated with their embryonic cousins.
Adult stem cell research, unlike studies employing embryonic stem cells, has not shown the same problem. As a result, only adult stem cells have been used to help patients with more than 100 diseases or medical conditions.
In a new article in the current issue of Cell Transplantation (Vol. 18 No.1), a team of Japanese researchers eliminated the problem of tumor growth by co-transplanting bone marrow stem cells along with embryonic ones.
The hoped to stop the embryonic stem cells from causing tumors when used to treat the effects of spinal cord injury in mice.
"Our study results suggest that co-transplanting [bone marrow cells] induce undifferentiated embryonic stem cells to differentiate into a neuronal lineage by neurotrophic factor production, resulting in suppression of tumor formation ," corresponding author Dr. Masahide Yoshikawa of the Nara Medical University explained.
"The known multipotency of bone marrow cells during differentiation and their known ability to produce neurotrophic factors, such as nerve growth factor, led us to speculate that co-transplantation of embryonic stem cells and bone marrow stem cells would provide an advantage over transplantation of embryonic stem cells alone," he added.
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.
Wesley J. Smith, a bioethics author and attorney, says the research into improving embryonic stem cells is unnecessary because adult stem cells already work to treat spinal cord injury patients.
"Adult stem cells in human trials have restored sensation to spinal cord injury patients with both paraplegia and quadriplegia," he explained.
The safety of adult stem cell transplants in spinal cord injury patients has already been proved in two clinical trials involving studies in Australia and Portugal.
The Australian research group reported its findings in the August 2008 edition of the medical journal Brain, saying that transplantation of autologous olfactory ensheathing cells into the injured spinal cord is feasible and is safe up to one year post-implantation.
In Portugal, a group headed by Carlos Lima also used autologous olfactory stem cell transplants and put them into the spinal lesions of paraplegic and tetraplegic patients.
In a July 2006 Journal of Spinal Cord Medicine article, they wrote that adult stem cells are beginning to offer the most hope for those paralyzed from spinal cord injuries.
Lima’s team’s adult stem cell research showed restored motor function and sensation in a few paralyzed patients using adult stem cells obtained from a patient’s own nose.
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