An international team of physicians and basic scientists from Johns Hopkins and Pittsburgh, from Switzerland, France, Germany Austria and the UK report in the Journal «Science Translational Medicine» about recent developments and break through results in developing therapy for such blinding diseases.
Mutations in 256 genes that are known to date lead to untreatable degenerations of the retina and represent one of the most prevalent causes of blindness. The retina can be imaged with about 100-fold better resolution with optical coherence tomography (OCT) than with e.g. MRI or CT. Adative optics, which was first developed in astronomy, allows to even image individual photoreceptors (the cells that can convert light into a neural signal) in the retina. Such reasons explain why latest therapeutic developments in medicine are applied specifically and primarily to the eye.
Under the leadership of Hendrik Scholl, MD, Professor of Ophthalmology, an international team of scientists report about break-throughs in therapy developments for inherited retinal degenerations. The exact understanding of the molecular mechanisms of the regereneration of the visual pigment in photoreceptors, which is disrupted in specific forms of Leber's congenital amaurosis (LCA) and Retinitis Pigmentosa (RP), has allowed to restitute this mechanism with an oral compound. Severely affected patients significantly recovered visual function in a multi-center clinical trial. Under Dr. Scholl's coordination, a worldwide phase 3 clinical trial has just started.
For replacing the defective gene viral vectors can be used and the healthy gene be delivered to the surviving cells of the retina. Such gene therapies have now been successfully conducted in several studies. For wider applicability such therapeutics should be injected directly into the eye (into the so-called vitreous body) and there has been recent success to develop such a route of administration. Dr. Scholl, the former co-founding and co-director of the Johns Hopkins Center for Stem Cells and Regenerative Medicine, and Dr. Mandeep Singh who is leading a lab for retinal stem cells at the Wilmer Eye Institute also report about recent break-throughs in stem cell therapy for retinal degenerative diseases.
A completely new approach using optogenetics as a therapeutic tool for retinal degenerations was developed by Botond Roska, MD, at the Friedrich Miescher Institute for Biomedical Research in Basel. This method allows to induce light sensitivity in retinal cells that are otherwise not light sensitive. Using a viral vector, a photoswitch gene is delivered into the vitreous of affected individuals who are completely blind. This therapy is about to be applied in a phase 1 clinical trial in patients who went blind from RP.
The retina has become a target tissue for new therapeutic approaches such as gene and stem cell therapy as well as microchip implantations and allows ophthalmology to be at the forefront of such developments in medicine.
Emerging therapies for inherited retinal degeneration
Hendrik P. N. Scholl, Rupert W. Strauss, Mandeep S. Singh, Deniz Dalkara, Botond Roska, Serge Picaud and Jose-Alain Sahel
Science Translational Medicine 07 Dec 2016: Vol. 8, Issue 368, pp. 368rv6 DOI: 10.1126/scitranslmed.aaf2838
Hendrik P.N. Scholl, MD, MA
Professor and Chairman
Department of Ophthalmology, University of Basel
Mittlere Strasse 91, CH-4031 Basel
Adjunct Professor of Ophthalmology
Wilmer Eye Institute, Johns Hopkins University School of Medicine
The Johns Hopkins Hospital
600 N. Wolfe Street, Baltimore, Maryland 21287