An overview of ex vivo stem cell gene therapies for EB
New scientific publication from Assoc.-Prof. Ulrich Koller, PhD from the EB House
A few years ago, the success story of a boy with junctional EB (JEB) who received a life-saving ex vivo stem cell gene therapy, went viral. Since then many EB patients wonder, whether they can also benefit from this kind of therapy. The molecular biologist Ulrich Koller who is doing research on this topic at the EB House in Salzburg, gives an update on the status of current and future stem cell therapy approaches for EB in two articles recently published in German in the medical journals "Der Hautarzt" and "Jatros Dermatologie & Plastische Chirurgie".
The ex vivo stem cell therapy already applied in EB patients involved a classical gene replacement strategy, in which a virus is used to insert a healthy copy of the mutated gene into patient’s own cells outside the body (= ex vivo). The corrected cells, producing a functional protein, are then grown to a thin skin that is transplanted onto wounds. Up to now, three JEB patients were treated with this therapy, and have shown medium to great success with no serious side effects. However, the same type of therapy was less effective for patients with RDEB, where the healthy protein was only produced for a short period of time. One explanation could be that the transplanted skin did not contain a sufficient amount of corrected stem cells. This, in turn, leads to the assumption that the success of the stem cell correction depends on the EB type and the affected gene.
It is known that the number of stem cells in the skin decreases with age and due to chronic wounds, such as those associated with EB. To increase the chances of success, stem cell gene therapies should thus be carried out at young age.
In recent years, modern gene therapy methods, in particular CRISPR have been introduced as an alternative to gene replacement therapy for the application in an ex vivo stem cell approach. These methods repair the mutated gene in the cells permanently, without the need of a virus, and are thus considered safer. However, this has yet to be demonstrated through safety analysis in cell culture. In addition, the results of ongoing clinical studies in other diseases will provide important insights to decide if this therapy is safe and efficient enough to be adapted for EB patients.
To access the articles published in the journal 'Der Hautarzt' please click here: Der Hautarzt