Clinical Trials of Stem Cell Treatment for SCI
A trial using human embryonic stem cell treatment for newly occurring SCIs is currently underway and aims to recruit ten patients to assess the safety of stem cells for spinal cord trauma. Geron, the company behind the trial, treated the first patient in October 2010 with their GRNOPC1 intervention that contains human embryonic stem cell-derived oligodendrocyte progenitor cells. What this means is that the stem cells have already been partially differentiated into cells which can aid in remyelination and nerve growth stimulation as previously shown in animal studies. Geron themselves have published research demonstrating partial restoration of function in animal models where spinal cord injury was induced. The survival rate of axons was one significant outcome found in such animal research, along with significant remyelination.
Better Post-Trauma SCI Care
Research using embryonic stem cells in animal models carried out by Salazar (et al, 2010) delayed treatment until 30days after the initial spinal cord injury was induced in mice to observe the possibility of extending the ‘window of intervention’ for patients. They used human neural stem cells to treat the injury and observed significant improvement versus controls in locomotor function. The extension of the treatment window perhaps demonstrated by this study may make it easier for patients to access stem cell therapy as part of a clinical trial where travel times and initial hesitation have been factors previously. Geron’s trial only accepts patients who have suffered SCI in the previous two weeks and with just seven centers across the country trained to accept patients this makes recruitment difficult.
SCI Stem Cell Trial Delayed
The Geron trial has also faced challenges as a temporary hold was applied by the FDA to the stem cell trial after evidence of cyst development was found in some animals injected with the stem cells during Geron’s own research. The hold was lifted in late July 2010 as Geron provided further evidence to show the safety of such treatments in animal models. The first patient on the trial, a student who suffered a spinal cord injury in a car accident was interviewed recently by the Washington Post although he, and Geron, have been cautious in discussing the effects of treatment so far. The trial is primarily investigating the safety of treatment but the researchers are also monitoring changes in sensation and movement which could offer hope to many of those with SCI. It remains unknown at this point if more patients have been recruited in the trial making it a long wait for those expecting great things from the experimental treatment. Even after Geron publish their results of this Phase I clinical trial they will still be required to go on to Phase II and III trials before a stem cell treatment for spinal cord injury can be eligible for approval by the FDA.
hESC Treatment for Spinal Cord Injury
The stem cell therapy represents an exciting advance in the field as legislation is relaxed on government funding for human embryonic stem cell research. The 2 million oligodendrocyte progenitor cells injected into the patient’s spine were derived from embryos left over from fertility treatments. The use of such surplus embryos is controversial, with passionate campaigning on both sides about the ethics of stem cell research. The actor Christopher Reeve, who himself suffered a spinal cord injury, established a foundation prior to his death in 2004 and greatly contributed to the push for stem cell research.
Glial Cells and Astrocytes
Further clinical trials are also anticipated using pre-differentiated astrocytes derived from human stem cells. Researchers in Colorado published a paper recently detailing their observations of glial cell differentiation in the laboratory under various conditions and found that two different astrocyte differentiation factors gave rise to astrocytes with quite different effects on axonal growth. Davies (et al, 2011) noted that the two resulting astrocyte types different expression of proteins thought to either promote or inhibit central nervous system homeostasis and regeneration, which would have significant consequences for any treatment of patients with glial-cell precursors rather than specific astrocytes. In the rat model one type of astrocyte promoted significant recovery of locomotor function and increased neuronal survival in spinal cord injury. A second astrocyte type failed to promote any significant recovery or neuronal survival and allows researchers to specifically implant those glial cells which have the best chance for repairing the damaged spinal cord in human patients.
Continue Reading –> The Safety of Stem Cells for Spinal Cord Injury
