RMCR Grant Lay Abstracts

2023 Lay Abstracts

“EYS on” gene editing for Retinitis Pigmentosa 25 

João Pedro Marques
University of Coimbra

The project “EYS on” gene editing for Retinitis Pigmentosa 25 aims to develop a new way to treat a type of inherited vision loss by fixing a particular genetic mistake in the retina. This genetic mistake is caused by a mutation in a gene called EYS. When this gene does not work properly, it can lead to a type of vision loss that gets worse over time and has no cure. We are exploring a technique called prime editing to fix a particular genetic defect, quite common in our patient cohort, in Portugal. This technique is like molecular scissors that can cut and paste the DNA in a very precise way. It is different from other gene editing techniques because it is less likely to make unintended changes to the DNA. To test whether prime editing can fix this particular genetic mistake in the EYS gene, we will use cells from patients with inherited vision loss. In the laboratory, these cells will be turned into tridimensional (3D)-mini-retinas which we expect will recapitulate the changes observed in the patient’s retinas. We will then use prime editing technology to correct the genetic mistake in these 3D-mini-retinas/cells and see if it works. We will study whether the corrected cells can show better morphology, survival or function than the cells with the genetic mistake. If the corrected cells work or survive better, this could be a promising new treatment for inherited vision loss caused by a mutation in the EYS gene. This research is important because there are currently no treatments for inherited vision loss caused by a mutation in the EYS gene. If we will be able to develop a new treatment using prime editing, it could help many people with this condition to see better and improve their quality of life.

2022 Lay Abstracts

Diet, lifestyle, systemic medication and genetics: can the risk for AMD be modulated? (AMD_LifeGene)

Cláudia Farinha
AIBILI – Association for Innovation and Biomedical Research on Light and Image

“The knowledge of how different risk factors, genetic and non-genetic, interconnect in AMD pathophysiology influencing its development and progression is of utmost importance.

Our group based in Coimbra performed the first epidemiologic AMD study in Portugal, the Coimbra Eye Study. Two cohorts from two primary Portuguese healthcare units (Mira and Lousã) were phenotypically characterized and risk factors were assessed. The overall prevalences of early and late AMD were similar to other large-scale population-based cohorts. However, AMD prevalence in Mira (a rural coastal town) was inferior to that in Lousã (an inland, more urbanized town). We arrived at the conclusion that the interplay between lifestyle and genetic background differences could be the cause of our reported epidemiologic findings.

With this new project, we aim to explore the interactions between AMD risk factors and their impact on AMD development and progression, in these two Portuguese populations with different reported lifestyles and AMD prevalence. Our primary objective will be to explore how the interplay between genetic, environmental, and lifestyle factors (e.g. Mediterranean diet), and systemic comorbidities/ chronic medications modulates the risk for AMD onset and progression in the global population of the Coimbra Eye Study and in each cohort (Mira vs Lousã). We will also characterize the genetics of our population, including rare variants analysis, explore genotypic-phenotypic associations and determine the 10-year incidence of AMD.

Risk of posterior staphyloma in highly myopic Europeans: from epidemiology to anatomy and back

Suzanne Yzer
Radboud University Medical Center

Background: Myopia (near-sightedness) is an endemic problem and is estimated to increase dramatically. Approximately 2.5 billion people worldwide are currently myopic. 20% of these have high myopia (refraction more than -6.00 Dioptres). This is frequently accompanied by complications, putting these patients at high risk of legal blindness. An important driver of these complications is Posterior Staphyloma (PS). PS is an outpouching of the posterior wall of the eye that results in progressive and irreversible damage of different retinal layers and eventually central visual loss. To date, there is no therapeutic intervention to constraint PS or its blinding complications. Virtually all studies on PS are from Asian populations and well documented large studies on Europeans are unavailable.

Aim: To estimate the frequency of PS in European high myopic patients and to study its functional consequences through a unique European collaboration and the constitution of a well phenotyped clinical database and biological biobank.

Approach: In a cross-sectional clinical study we will use multiple devices for imaging of the posterior part of the eye in order to grade PS in high myopic Europeans from hospitals in The Netherlands, Spain and France according to a standard grading system. DNA and additional body materials (like sclera) from high myopes with or without PS will be collected. Well characterized large cohorts will assist in the interpretation of laboratory studies, like future DNA studies and aid in unravelling the underlying mechanisms of PS development. We will perform our research in a unique European consortium to provide distinctive information on PS patients from European descent.

Outcome: Creation of a European clinical and biologic database for future studies on PS, which is an increasing major visual health issue, not only in Asians but also in the European population.

2021 Lay Abstracts

Microbiome, metabolome and complement activation in age-related macular degeneration

Prof. Robert P Finger
University Hospital Mannheim

Prof Zeinab Abdullah
University Hospital Bonn

Age-related macular degeneration (AMD) is a very common retinal disease associated with ageing. Its early stages affect about one third of persons 70 or older and those are at risk of progression to late AMD stages which often cause severe irreversible vision loss. Consequently, late AMD is the main cause of severe vision impairment in Europe. Today, we still do not fully understand this disease and who might be at risk of progression. We also do not have any treatments to prevent AMD, stop or delay its progression. We know that AMD is associated with inflammation and a dysregulation of the immune system including elevated levels of inflammatory markers in the blood and a reduced capacity for waste removal called phagocytosis. Recently, the bacteria living in our guts (i.e. the microbiome) have been related to inflammation and to AMD. The microbiome impacts how our guts process food and thus the metabolites we resorb as well as levels of inflammation in our blood and elsewhere in our bodies. However, this has not been assessed all in one study yet. In order to understand AMD better we will comprehensively assess AMD status, the microbiome, the metabolome (i.e. metabolic products) and levels of inflammation as part of the immune system. All this together may help us to better understand AMD and unravel novel biomarkers that are linked to increased or decreased risk of disease development.

REGENT (RETiNal GENE ThERapy immunNE REspoNsE)

Dominik Fischer
Oxford University Hospitals NHS Foundation Trust

Viral infections can damage the eye. Antiviral immune responses can lead to additional problems for the eye. The ocular immune privilege is a clever way of nature to limit such secondary damage. However, this privilege is potentially compromised by disease processes and surgical trauma. Surgical delivery of adeno-associated virus (AAV) potentially induces gene therapy (GT) associated inflammation after ocular delivery in patients with pre-existing retinal disease. Progress has been made addressing innate immune response to AAV, but not regarding adaptive immunity: Anti-AAV antibody titres do not correlate or predict the risk of inflammation or its severity; but adaptive immune cells have the potential to limit therapeutic effects of GT (50% therapeutic effect is lost within first year via immune-mediated clearance of treated cells in liver). Immune-mediated clearance of treated cells in the eye could explain an observed decline in functional benefit following ocular GT. It is therefore crucial to better understand the risks, consequences, and best management of GT related inflammation. In this project, we utilize a unique biobank of samples taken from patients and model systems exposed to therapeutic AAV. Hypothesis driven analysis of these samples will help to 1) test, whether subretinal gene therapy leads to increase in ocular and systemic inflammation markers beyond the expected postsurgical recovery phase; 2) identify biomarkers of cellular adaptive immunity that can predict risk and severity of GT associated inflammation; and 3) identify biomarkers of adaptive immunity that can be used to quantify and monitor such an inflammatory response. Closing these knowledge gaps will provide a unique opportunity to identifying strategies of targeted intervention limiting potentially detrimental effects of an immune response against therapeutic virus used for gene therapy.

2020 Lay Abstracts

Metabolomics: A Novel Tool for Investigating the Pathogenesis of Age-related Macular Degeneration (AMDMetab)

Rufino Martins da Silva
AIBILI – Association for Innovation and Biomedical Research on Light and Image

Age-related macular degeneration (AMD) is a disease that affects the macula, the central area of the eye that is responsible for vision. Some people with AMD remain very stable over time, while other progress to the blinding stages of the disease. Currently, there is very little to offer to patients with AMD to prevent them from progressing to the late blinding forms of the disease. This is because we don’t completely understand why progression happens. We know that both genetic/ inherited factors and exposures (such as smoking) are related to progression, but we don’t have enough information about the exact mechanisms that lead to progression in some patients. This study aimed to gain insights into the mechanisms behind AMD progression. To do so, we recruited patients with AMD and a control group and assessed changes in their blood profiles at 5 years. To assess their blood profiles, we used a technique named metabolomics, which is the study of the small little particles in our blood that result from gene expression but are also affected by environmental exposures. Our group had previously shown that this technique (metabolomics) was good to assess AMD, but until now we had not followed people over 5 years. Our results in this project showed that indeed certain metabolites at baseline were associated with a higher risk of developing worse AMD, and that changes in the levels of certain metabolites (i.e., comparing their baseline levels with 5-year levels) were related to progression of the disease. This is important because it gives us information on the exact mechanisms of AMD progression and with further research can help develop treatments to stop the progression of the disease.

“The C-type lectin receptor CD93 as a new target in retinal vascular diseases”

Gian Marco Tosi
University of Siena

Anti-VEGF drugs have revolutionized the treatment of neovascular eye disease and provide significant visual benefits. Although this strategy has proven successful in some patients, the efficacy of neovascular inhibitor therapy remains to be improved. The discovery of new targets with complementary endothelial function may provide new opportunities to circumvent resistance mechanisms and improve current therapeutic treatment. The goal of this project was to characterize a new endothelial target and develop new tools for the treatment of retinal vascular diseases. Thank you to the Euretina award, we gained relevant insights into the molecular mechanisms controlling angiogenesis in neovascular retinopathies, which has important biological and translational implications. Indeed, we have developed a new monoclonal antibody that can neutralize the novel endothelial receptor CD93 and block blood vessel growth. Through genetic engineering, we have derived a recombinant antibody that has the same neutralizing effect as the original antibody, but can be produced and purified on a large scale for various applications. For example, we have produced recombinant antibodies conjugated with toxic agents and used them to kill proliferating but not quiescent endothelial cells. In addition, we are testing the recombinant antibody in a specially generated animal model of neovascular retinopathy to provide evidence of its therapeutic potential. Our team is confident that further development of this new agent can benefit patients with neovascular eye diseases.

2019 Lay Abstracts

Juvenile X-linked retinoschisis: assessing the clinical and genetic spectrum in preparation for therapy

Camiel Boon
Amsterdam University Medical Centre

X-linked retinoschisis (XLRS) is an intriguing and relatively common genetic eye disease caused by mutations in the RS1 gene. Mutations in this gene lead to splitting between different retinal layers in affected men, which often causes  severe loss of vision starting at young age. Patients with XLRS also have an increased risk for vision-threatening complications such as detachment of the retina, that regularly require surgical intervention. Currently, there is no treatment available for XLRS, but gene therapy in mice has shown promising results and first steps have been taken to study gene therapy in humans. To date, strikingly little is known about the natural disease course, clinical variability, frequency of complications, outcome of surgery in XLRS.

We will perform the clinical largest study to date on XLRS, with the following aims:

  1. To achieve a detailed description of the natural disease course and clinical variability.
  2. To assess how often complications occur and what the outcome of (surgical) intervention is.
  3. To determine which patients may be the best candidates for future (gene) therapy and which disease characteristics are most suitable to monitor the effectiveness of gene therapy.

Our study will be coordinated at the Expertise Centre for Hereditary Eye Diseases of the Amsterdam University Medical Centers. Participants will be collected from our own large database, in collaboration with all other Dutch expertise centers from the RD5000 consortium, as well as the Ghent University Hospital (Belgium). We expect to include at least 300 participants, with confirmed genetic testing at our certified DNA diagnostics laboratory. The data collection will include detailed genetic and clinical data with elaborate multimodal imaging and ophthalmic examinations.

This study is crucial to provide an accurate prognosis of disease progression, risk of complications, and outcome of surgery for XLRS patients. Furthermore, our results will be an important milestone for the successful patient selection for future (gene) therapeutic trials through the identification of appropriate clinical endpoints.