Olfactory Ensheathing Cells & Spinal Cord Injury Cure

Damage to the spinal cord

Damaging the spinal cord prevents nerve messages travelling to and from the brain. These messages control most functions of the human body, including touch and sensation, muscle movement, bladder control and sexual function. With the loss of these messages, the body is paralysed below the level of injury.

Can nerves in the spinal cord re grow after injury?

Repairing damage to the spinal cord is very complex, as there are many spinal neurons killed by not only the initial injury, but in the hours, days and weeks following the accident. More neurons are also killed as the body begins to kill neurons close to the injury site (secondary damage). 

As the nervous system develops in the foetus, some nerves cells are programmed to die after they have finished their usefulness. In a spinal cord injury, this self destructive mechanism is triggered again, and some of the neurons around the injury site begin to self destruct or commit suicide in a process called apoptosis.

During the body's response to an injury to the spinal cord, the body forms an impenetrable scar tissue at the site of the injury which acts as a barrier to any neurons that might be trying to grow. Any neurons which have escaped damage may lose their insulating myelin sheath, and so can’t function and pass messages to and from the brain via the spinal cord.

To repair a spinal cord injury, scientists not only have to solve all the problems above, but would then need to find a treatment which makes the neurons grow in exactly the right part of the spinal cord, and form synapses with exactly the right neurons.

Regenerating spinal cord neurons

In order to encourage the damaged neurons to grow again, a way needs to be found to stimulate the neurons by introducing growth factors.

One of the most recent discoveries is the olfactory ensheathing cell (OEC), also known as the olfactory ensheathing glial cell (OEGC), which is taken from the lining of the nose.

When the olfactory cells are added to a solution containing a scar reducing compound, and the combined solution is added to a damaged spinal cord in rats, the spinal cord was shown to regenerate resulting in a recovery of sensation and movement. The olfactory ensheathing cells provide an environment that promotes axon growth.

Geoff Raisman and his group in London have found ways of injecting these olfactory ensheathing cells into the spinal cord of humans.

The results have been very encouraging and human trials will begin in collaboration with The Royal National Orthopaedic Hospital, Stanmore. When these olfactory ensheathing cells come in contact with the normally barrier-like astrocytes of the glial scar. ‘It’s almost like they knock on the door and the astrocytes open up’ said Geoff Raisman.

Further research and trials are ongoing which include an enzyme to break down the inhibitory proteoglycans in the glial scar tissue to allow neurons to grow, the use of Schwann cells (from the peripheral nervous system) to encourage nerves to grow, and Olfactory ensheathing cells to ensure the axons could grow out of the graft and back into the spinal cord.

To discuss the above issues more, please visit the Research Forum