One should remain cautious concerning the interpretation of the results of the Asterias clinical trial, which consists in testing the administration of oligodentrocytes obtained from human embryonic stem cells on patients suffering from spinal cord injuries. Jacques Suaudeau remains prudent about the eulogistic comments that were given over the past few day concerning a tetraplegic patient who apparently recovered the use of his arms and hands. In the present conditions it is impossible to say whether the improvement of his state is indeed related to the treatment or not (cf. Human embryonic stem cells and overenthusiastic media).
Firstly because before being administered the oligodendrocytes  the patient had clearly already experienced spontaneous improvement: it was reported that he spontaneously freed himself from the respirator. It is therefore not a case of traumatic quadriplegia but rather a commotion, which supposes there is a good possibility of partial recuperation thanks to willpower, high spirits and intensive physiotherapy.
Besides, what we are dealing with here are oligodendrocytes and not stem cells. Oligodendrocytes cannot repair a spinal cord injury, but help the myelin sheath which surrounds the neurons to reconstitute. They also have a beneficial action on neural cells. Experimentally, a positive action of oligodendrocytes on a spinal cord injury can be seen only for contusions, without rupture, and therefore without any axon separations. It must be the case for this patient.
A treatment by embryonic stem cells aiming at repairing the neurons themselves would be different. Experimentally, the effect was shown on rats’ years ago, but until now, the results don’t seems to be very impressive.
In order to admit that injections of oligodendrocytes (AST-OPC1) may have a proven beneficial effect on spinal cord injuries, all the patients of that group would have had to benefit from it. It is not the case. One single case is no proof, apart from showing that the oligodendrocytes may have had a positive trophic action on an injury caused by commotion with the possibility of a partial spontaneous recuperation.
Another argument doesn’t play in favour of the so-called “spectacular results”: Asterias Biotherapeutics presented the case in mid-September during a congress in Vienne, but outside of the scheduled official meetings. And neither Nature nor Science wrote a single line about this “case”.