A bit of scientific controversy with MS implications...
Enlisting the immune system to fix broken spines
22 August 2006 -- NewScientist.com -- A vaccination that stimulates immune cell production could be key to enabling people with serious spinal injuries to walk again, researchers say.
However, the study has been criticised by some experts in the neurological field who remain sceptical about the findings.
The controversial research claims come from a team at the Weizmann Institute of Science in Rehovot, Israel, who say that key immune cells can work with stem cells to mend broken spines in mice.
Their latest study involved a vaccine that increased the numbers of immune cells, known as T-helper cells, that specifically protect myelin – a protein that coats nerve cells. The vaccine encouraged and protected stem-cells in the spine as they grew and become nerve cells, to such an extent that previously crippled animals were able to resume walking, they say.
However, the new claims have reignited a major controversy in neuroscience.
Traditional theory suggests that the delicate central nervous system needs to be isolated from the heavy-handed cells of the immune system in order to function properly and affect repairs.
Michal Schwartz, who led the latest study, has spent the last 10 years working on a different theory: that a significant degree of immune system involvement is needed for the central nervous system to repair itself.
In February 2006, Schwartz published a study in Nature Neuroscience demonstrating that immune cells had an important role in nerve cell regeneration.
Now she reports that by boosting T-cells at the same time as injecting mice with stem cells that had partially differentiated into nerve cells, she was able to reverse severe spinal damage.
Injections of the stem cells without the T-cell-stimulating vaccine had little effect. Significantly, the myelin vaccine alone had more effect than simply injecting stem cells, she says.
The findings suggest that “immuno-supressive drugs should not be used” with future stem-cell therapy for spinal injuries, she says.
The team simply injected the animals’ soft tissue, so invasive, intra-spinal injections would be unnecessary, they believe.
Schwartz’s belief that key neurological diseases, such as multiple sclerosis, are caused by an over-active immune system has been greeted with some scepticism, however.
Geoffrey Raisman, director of University College London’s Spinal Repair Unit, was unequivocal in his denouncement. “There is no scientific basis for this paper,” he told New Scientist.
“The experiments reported do not have validity. It is beyond the bounds of possibility that this approach could improve spinal cord injury. I am surprised that it was published,” he adds.
Another leading researcher in this field, Phillip Popovich at Ohio State University, US, has been less critical of Schwartz’s theories, describing them as “encouraging”. He too, however, has called on more substantial animal research to be done before tests on humans are even considered.
Schwartz cites papers she has published in recent years in reputable journals such as Nature Medicine and the Journal of Clinical Investigation as support for her theories. “I’m aware that this research is controversial. I think that neurologists are not aware of the diverse functions of the immune system,” she says.
“I think they’re locked into the concept that the immune system can be only detrimental to the central nervous system. But I think there’s clearly evidence now to say that’s not the case.”
Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0603747103)
http://www.newscientist.com/article/dn9 ... pines.html