Novel gene therapy

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After a spinal cord injury, the body forms a scar to limit the injury site and prevent further damage. This barrier also blocks the regeneration of damaged nerves. Researchers found that the enzyme chondroitinase ABC softens the scar tissue. To make the enzyme therapeutically usable, gene therapy is used.
In doing so, new genetic information is introduced into the cells by means of a vector, e.g. the information for formation of chondroitinase ABC. The problem: So far, the vector system was recognized by the immune system and inactivated after some time and thus ineffective.

Better control
A team of scientists at King's College London has now developed a new gene therapy approach under the direction of Professor Elizabeth Bradbury.
The group developed a vector for chondroitinase ABC and made it possible that the immune system no longer recognizes this newly introduced gene as foreign and thus does not inactivate it. This gene is very well controlled and can be switched on and off, if necessary by the administration of antibiotics drinking water. This allows a control for the time during which the enzyme is expressed. It improves its effectiveness, reduces possible side effects and promotes regeneration.

Substantial recovery
The study showed that spinal cord injured rats recover well with this therapy. Nerves grow back and functions that have been lost after the injury are restored. This allowed the animals to regain control of their front paws. This positive effect has so far only been achieved with “fresh” injuries, but scientists now want to use this approach to investigate older, chronic injuries.

Further steps
Gene therapy in humans is still in its infancy. Based on the current positive results, this therapy could in the future enable a restoration of manual functions for quadriplegics - a tremendous improvement in their quality of life and independence. Now the next steps have to be taken - always with the attention to the fact that the treatment is controllable and has no side effects for the patient.

Wings for Life was supporting this important research. The prestigious journal Brain published these results.

Source: “Immune-evasive gene switch enables regulated delivery of chondroitinase after spinal cord injury”. Burnside ER, De Winter F, Didangelos A, James ND, Andreica EC, Layard-Horsfall H, Muir EM, Verhaagen J, Bradbury EJ. Brain, June 2018.