Correspondence

Nature 458, 1101 (30 April 2009) | doi:10.1038/4581101a; Published online 29 April 2009

Stem-cell treatments for spinal-cord injury may be worth the risk

Jesse Owens1

  1. Biomedical Program, University of Alaska, Anchorage, Alaska 99508, USA
    Email: afjlo@uaa.alaska.edu

Sir

In his Correspondence 'Caution urged in trial of stem cells to treat spinal-cord injury' (Nature 458, 29; 2009), Yves Barde questions the wisdom of testing oligodendrocyte precursors derived from embryonic stem (ES) cells in patients, despite the promise that such cells hold for repairing these injuries in rodents.

After traumatic injury to the spinal cord, the axons adjacent to the lesion often remain intact but become demyelinated (J. Silver and J. H. Miller Nature Rev. Neurosci. 5, 146–156; 2004). Stem cells derived from adult or embryonic sources can remyelinate denuded axons and restore limited, but significant, recovery of function (see, for example, M. Sasaki et al. Prog. Brain Res. 161, 419–433; 2007). It is therefore plausible that treatment with oligodendrocyte precursors might perform similarly in humans.

I concede Barde's point that there are other issues to consider in developing a comprehensive treatment for paralysis, including axon regeneration, axon-growth inhibitors and the lesion scar. But even partial restoration of function through remyelination would yield valuable improvements in patients, including an ability to breathe independently, enhancement of hand dexterity, recovery of sexual function and restoration of bowel and bladder control.

There is evidence for some degree of recovery from spinal-cord injury in animals after experimental cell transplantation alone, or in combination with other agents. But as the rest of the world moves forwards in developing human treatments in this area, the United States lags behind. Given the severity of such injuries and the often-overlooked fact that a patient's condition deteriorates steadily over time, a calculated degree of risk may be justified in pioneering clinical efforts to resolve the dilemma of lifelong paralysis.

People from the United States with spinal-cord injuries are flocking to clinics around the globe for cell transplantations despite warnings from the scientific and medical communites about the potential dangers — largely because of the paucity of treatment options at home. The US Food and Drug Administration's forthcoming safety trial using ES cells in humans with spinal-cord injuries (see Nature 457, 516; 2009) is therefore a long-awaited and welcome first step.


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