Experimental Ophtalmology
The experimental ophthalmology group is a research and teaching center focused on optimizing the treatment of retinal diseases, such as age-related macular degeneration (AMD) and diabetic retinopathy. We are interested in regenerative and personalized medicine, and are developing cell-based, GMP-compliant (Good Manufacturing Practice) Advanced Therapy Medicinal Products (ATMP) to treat neurodegenerative diseases of the eye by developing regenerative gene therapeutic approaches, like the transplantation of genetically-modified cells. Additionally, we are working with new biomaterials and drug application systems.
Currently, our research efforts involve the following projects:
Transposon-based gene cell therapy for the treatment of retinal neurodegeneration
In the TargetAMD project,
) we developed a cell-based, personalized gene therapy treatment for neovascular (“wet”) AMD
. The project was coordinated by Prof. G. Thumann and was funded by the European Union’s Seventh Framework Program
for research, technological development and demonstration” (no. 305134), and carries on thanks to a grant financed by the ProVisu
foundation. The therapy aims at suppressing vessel growth and at regenerating retinal architecture.
The project comprised various in vitro and in vivo development and validation steps during which we confirmed the efficiency and tolerability of the approach. After validation of the GMP-grade production of genetically modified iris pigment epithelial (IPE) cells, we received approval from the cantonal ethical commission for research (CCER) to perform a clinical phase Ib/IIa study. We are now awaiting approval from Swiss authorities, Swissmedic. The procedure comprises IPE cell isolation from an iris biopsy (figure A & B), genetic modification by the addition of the PEDF gene (Pigment Epithelium Derived Factor) using the Sleeping Beauty transposon system (figure C), and subretinal transplantation to the same patient (figure D), all within a single surgical session.
In contrast to wet AMD, in atrophic ("dry") AMD, the loss of retinal pigment epithelial (RPE) cells probably results from inflammatory reactions and oxidative stress. Based on the non-viral gene therapy approach developed in TargetAMD, we aim to transplant genetically modified cells to continuously provide neuroprotective growth factors to the retina, to prevent further loss and degeneration of the RPE. In collaboration with Prof. L. Scapozza, UNIGE, we investigate in an in vivo model of dry AMD, whether the transplantation of genetically-modified RPE cells supposed to express the genes coding for the proteins PEDF and GM-CSF (granulocyte macrophage-colony forming factor) prevents efficiently RPE cell death. We hypothesize that transplanted RPE cells will re-establish a neuroprotective retinal environment and inhibit the progression of the degeneration. Restoration of vision is analyzed by functional, behavioral, cellular and molecular methods. After in vitro proof-of-concept studies, we hope to demonstrate, in partnership with Prof. Z. Izsvák, Paul-Ehrlich Institute, the safety of the treatment. This project is funded by the Swiss National Science Foundation (SNSF grants no. 160195 and no. 18889341).
Retinal organotypic culture as valuable 3R compliant ex vivo model to test new drugs and therapies. In this project, we are culturing not only cells but the whole retina, and mimic pathogenic conditions (e.g. oxidative stress) to develop ex vivo models of retinal neurodegeneration, e.g., for dry AMD or diabetic retinopathy. Subsequently, the neuroprotective capacity of potentially therapeutic, protective proteins (PEDF and GM-CSF) overexpressed in transfected cells can be assessed by biochemical and immunohistological analyses (SNSF grants no. 160195 and no. 189341; ProVisu foundation).
Ocular in vivo electroporation to treat retinal neurodegeneration. In this project, we are developing a novel transfection method using in vivo electroporation to target the RPE. Our goal is to simplify the treatment approach, and to increase the therapy’s safety. We are currently working with an eye model similar in size to human eyes. Further we plan to investigate an RPE-specific promotor to increase the safety profile of the approach. This project is carried out in collaboration with Prof. Z. Izsvák, Max-Delbrück Center for Molecular Medecin in the Helmholtz association (Schmieder-Bohrisch foundation; AURIS foundation).
Biomarker profiling in tear fluid to enhance prevention and diagnosis of diabetic retinopathy. The actively proliferating diabetic retinopathy (APDR) is the leading cause of blindness in working-age adults, and in this study, we aim to develop a diagnostic tool, which allows differentiating between patients who are predisposed to severe APDR, from those likely to develop only a mild form or no retinopathy. To this goal, tear fluid samples will be collected and multiomic profiles determined in collaboration with Prof. Golubnitschaja, University of Bonn, to identify biomarker candidates or biomarker patterns specific for distinct disease forms or phases. Tear fluid samples are easily and non-invasively collected, and their multiomic profiles reflect well the health status of a person, enabling fast, simple and personalized diagnosis and efficient and personalized management of diabetic patients (LHW private foundation).
Xenofree ocular cell culture
using human platelet lysate to develop personalized therapy approaches. ATMPs, including regenerative, genetic and cellular therapies, have special requirements for production and quality control. One condition is a cell culture system free of xenogeneic reagents to increase product safety; additionally, the use of FBS-alternatives is ethically favorable. We are developing a xeno-free cell culture system for ocular cells by using human platelet lysate from blood donation that satisfies both, the 3R principles of animal experimentation, and quality requirements of our cell products. The use of autologous platelet lysate to culture autologous cells will additionally improve patients’ security.
Other research interests include the development of quality controls for ATMPs using Raman spectroscopy; the analysis of the neuroprotective activity of scutellarin and the toxicity of decaline on the neural retina; the measure of the role of lysyl oxydase in diabetic retinopathy. In collaboration with Prof. D. Ghezzi, EPFL, we have established an in vivo model for the implantation of self-opening, intra-neural electrodes that allow stimulation of the optic nerve and the recording of its electrophysiological activity to restore vision through optic nerve prosthesis. Our clinical research comprises the transfer of therapeutic approaches developed in our laboratories into the clinic and clinical trials for new drugs and innovative surgical procedures (https://www.hug.ch/ophtalmologie/recherches-cliniques).
PUBLICATIONS OF THE GROUP