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 regenerative and personalized medicine, such as the development of cell-based, GMP-compliant (Good Manufacturing Practice) Advanced Therapy Medicinal Products (ATMP) to treat neurodegenerative diseases of the eye. We use regenerative gene therapeutic modalities, such as transplantation of genetically-modified cells and stem cells, and are developing 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, (www.targetamd.eu) we developed a cell-based, personalized gene therapy treatment for wet AMD that suppresses vessel growth and regenerates retinal architecture. The project comprised a number of steps, each of which was developed and validated in vitro and in vivo. After validation of the GMP-grade production of genetically modified iris pigment epithelial (IPE) cells, we applied for a clinical phase Ib/IIa study. Having received approval from the cantonal ethical commission, we are now awaiting approval from the Swiss authorities. In this procedure, IPE cells isolated from an iris biopsy (figure A & B) are genetically modified in a GMP-facility by the addition of the PEDF gene to the cell’s genome using the Sleeping Beauty transposon system (figure C). Then, these cells are transplanted into the subretinal space (figure D) of the same patient, all within a single surgical session. The project is coordinated by Prof. G. Thumann and was funded by the "European Union’s Seventh Framework Programme for research, technological development and demonstration,” under the grant agreement no. 305134. In contrast to wet AMD, in atrophic AMD the loss of retinal pigment epithelial (RPE) cells is not associated with the growth of new blood vessels but instead inflammatory reactions and oxidative stress. Evolving the non-viral gene therapy approach developed in TargetAMD in a SNF-funded project (Swiss National Science Foundation, no. 160195), we are actively working on the transplantation of cells that have been genetically modified to continuously provide neuroprotective growth factors to the retina, which would then prevent further loss and degeneration of the RPE. After in vitro proof-of-concept studies, we hope to demonstrate the safety and efficacy of the treatment in vivo models.
We will extend both approaches through a regenerative therapy using non-virally transfected stem cells. The aim of this project is to both replace degenerated retinal cells and create a neuroprotective environment that prevents further cell loss. In collaboration with Prof. Z. Izsvák, MDC, we will develop methods to manufacture and culture the cell product in xenofree conditions and test the neuroprotective and regenerative potential of the cells in vitro. Working with Prof. L. Scapozza, UNIGE, we will investigate whether the transplantation of genetically-modified stem cell-derived RPE cells effectively prevent further loss of RPE cells in an in vivo model of dry AMD. We hypothesize that transplanted stem cell-derived RPE cells will re-establish a neuroprotective retinal environment and replace the degenerated retinal cells. Restoration of vision will be analyzed by functional, behavioral, cellular and molecular methods. (Funding: FP7 programme of the EU grant agreement no. 305134, SNF project no. 160195)
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 retinal pigment epithelium (RPE). Our goal is to streamline the transfection process and avoid possible complications from transplantation. As a model, we are currently working with eyes, similar in size to human eyes. Further, we plan to investigate in a RPE-specific promotor to increase the safety profile. (Funding: AURIS and Schmieder-Bohrisch foundation)
Retinal organotypic culture as valuable 3R compliant ex vivo model to test new drugs and therapies. In this project, we aim to induce retinal degeneration in a retinal organotypic culture system, as an ex vivo model of retinal neurodegeneration as in dry AMD. The neuroprotective capacity of 2 multifunctional proteins overexpressed in transfected cells (PEDF and GM-CSF) will be assessed by biochemical and immunohistological analysis. (Funding: SNF project no. 160195)
Xenofree ocular cell culture using human plasma lysate to develop personalized therapy approaches. ATMPs, including regenerative, genetic and cellular therapies, have special requirements for production or control in contrast to pharmaceuticals. One such specification is avoiding the use of xenogenic reagents for cell culture, due to ethical and safety concerns. Therefore, it is crucial to develop manufacturing procedures without the use of animal reagents. In this project, we are developing a xenofree cell culture system for ocular cells by using human platelet lysate from blood donation. Human platelet lysate, in this context, can be used once it has passed the expiration date for blood transfusion. Thus, alternative may offer a solution that both satisfies the 3R principles of animal experimentation and to improves the quality of our cell products. Further, using autologous platelet lysate instead of animal reagents to culture autologous cells would drastically improve patients’ security.
Other research interests include the development of in-process 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.