Inaugural Gisbert Richard lecture explores artificial vision and stem cell therapy

Prof Gisbert Richard receives the certificate for the inaugural Richard Lecture from EURETINA president Ursula Schmidt-Erfurth Prof Gisbert Richard, Germany, delivered the keynote presentation yesterday as the inaugural speaker of the new Gisbert Richard Lecture. “The fact that EURETINA has grown from 300 members at its inception to more than 5,000 members today is in large part due to Gisbert’s great vision and perseverence in building the organisation,” said Prof Jan van Meurs, The Netherlands, in his introduction of Prof Richard. Prof van Meurs, the incoming President of EURETINA, said he was honoured to introduce Prof Richard, who he called “a vitreoretinal surgeon who has worked on the forefront of the field, specifically in artificial vision and cell transplantation as treatments for chorioretinal degeneration.” Prof Richard’s keynote lecture was entitled ‘Restoration of Sight: Prospects and Limitations of Artificial Vision and Stem Cell Therapy’. “About two million people worldwide suffer from photoreceptor degenerative diseases. It is therefore crucial that research continues, and that we continue working on the primary problems inherent to the treatment of these diseases,” said Prof Richard. “The first problem is the interdependence of different layers of the retina, which means that retinal pigment epithelium (RPE) degeneration leads to both degeneration of the choriocapillaris and focal necrosis of photoreceptor cells,” he said. “The second problem is the timing of a therapeutic intervention. Is it better to intervene early, before the damage has occurred?” he asked. “Or later, when the risks of making it worse have lessened?” As it turns out, that depends on which type of therapy is administered. “The third problem is that of additive RPE aging.” This refers to the various ways in which RPE cells degenerate, losing their typical cell morphology and undergoing atrophy and hyperpigmentation. “This physiologic aging also causes secondary alteration of the choriocapillaris and retina.” Prof Richard discussed the treatment options in depth. Broadly speaking, there are three therapeutic categories: cell therapy, gene therapy and retinal prostheses. Cell therapy refers to the transplantation of either HLA-typed RPE cells or stem cells, or a more pharmacologic approach to the diseased cells. “Cell therapy requires the establishment of an RPE cell bank in order to isolate and cultivate human adult RPE cells,” he explained. “HLA-typed RPE transplantation has been shown to be a safe procedure, with no rejection of transplanted cells and limited improvement of visual acuity,” said Prof Richard. “However, there remains the problem of progression of geographic atrophy.” “To date, there is evidence from animal experiments that stem cells and retinal progenitor cells can be used for cell therapy,” he said. Gene therapy focuses on treatment of early stage disease. “Because these diseases are monogenetic, they are ideal candidates for gene therapy,” he added. “The goals include replacing or knocking down a defective gene, controlling gene expression, delivering a suppressor or correcting a mutation that misdirects splicing.” “Ongoing and anticipated gene therapy trials include treatments for LCA Type 2, choroideremia and LHON,” said Prof Richard. He then covered retinal implant (prosthetic) technology. “Visual improvement by retinal stimulation is definitely possible, and surgical challenges can be properly managed,” he said. “However, high-resolution implants are difficult to achieve.” “Who knows what the future will hold? Electrodes in the subretinal space?”