08. December 2016

Significant vision improvements in blind people

The retina is part of the central nervous system and the basis of our sense of sight. Frequently, the retina is affected by hereditary diseases that were untreatable until now. At present, an international research team headed by Prof. Hendrik Scholl, the new Chief Physician at the Eye Clinic of the University Hospital of Basel, is reporting progress in the development of therapy and a breakthrough in the treatment of blindness.

 

Currently 256 gene mutations that can lead to untreatable retinal diseases are known. The main characteristic of such retinal degeneration is a progressive loss of nerve cells in the eye. Retinal degeneration is the most common cause of blindness among 20- to 60-year-olds in Central Europe. Now, according to an international research team headed by Prof. Hendrik Scholl, Chief Physician at the Eye Clinic of the University Hospital of Basel, a breakthrough has been made in treating inherited retinal degeneration.

An overview article recently published in the renowned Science Translational Medicine journal summarizes the latest state of research, which has reached a remarkable point: significant sight improvements have been achieved in blind patients. It has been shown that through precise knowledge of molecular mechanisms the visual pigment can be restored with a drug. The drug in question (zuretinol acetate) has already been successfully tested in a first phase. Now, the effect is being further researched in a worldwide phase 3 study headed by Prof. Scholl.

Gene therapy in retinal diseases

Equally impressive is the finding that a defective gene in the retina can be replaced by delivering a healthy gene to surviving cells via viral vectors. Such gene therapies have already been repeatedly used with success in retinal diseases. For wider use of such therapies, appropriate therapeutic agents must be injected directly into the vitreous body of the eye. Substantial progress has been made in this respect.

An entirely novel therapy method was also developed by Prof. Botond Roska of the Friedrich Miescher Institute, associated with the University of Basel. He was able to make non-light-sensitive cells light-sensitive by means of optogenetics. For this purpose, a viral vector is used for an intravitreous injection of a “photoswitch gene”. This therapy would be a true ray of hope for those who have practically no remaining light sensitivity. A phase 1 study with patients will be launched soon to further develop this method.

In his article, Prof. Scholl  reports about success not only in gene therapy, but also in stem cell therapy. Such advances have been possible because the retina can be imaged with about 100 times better resolution using new imaging methods than, for example, using magnetic resonance imaging (MRI) or computer tomography (CT). Using this technology, individual cells that transform light signals into electric signals can now be imaged in living people. In this way, the latest developments in gene and stem cell therapy can be tested specifically in the eye.