Identification of Cellular Biomarkers of Rare Eye Diseases in Adults

The cornea is the outermost transparent 'window' of the eye allowing light to enter and serving as the first-line immune and mechanical barrier. It is a complex avascular tissue composed of cells, stem cells, nerves, and collagen layers organized in an exquisite manner to maintain its transparency and self-healing capacity. This delicately balanced interplay of corneal elements is disrupted in rare diseases of the cornea, resulting in non-healing wounds, corneal ulceration, inflammation, new vessel ingrowth (neovascularization), defective innervation, scarring, oedema and loss of transparency. For many Rare Eye Diseases (REDs), drug development has been relatively unsuccessful, delivering few to no new therapies. Current management is often prohibitively expensive, has low efficacy and leads to debilitating side effects. The RESTORE VISION project (https://restorevision-project.eu/) aims to improve eye health by using cutting-edge models for each rare disease to test novel and repurposed compounds (9 in total) and determine drug mechanisms of action, formulating compounds as safe eye drop suspensions, and performing several first-in-human trials of novel therapies. Thes drugs have solid preliminary data showing beneficial effects in restoring the cell physiology, immune, avascular, neural and signaling environment in the cornea. The current clinical study is part of Work package 2 within the RESTORE VISION EU grant agreement (''Validation of human drug targets of repurposed drugs and novel therapies'') and aims to ascertain the expression levels of genes and proteins and investigate pathways of interest in human tissue and fluid samples of REDs, that are targeted by the proposed experimental/repurposed substances. Therapeutic target gene and/or protein expression will be verified in human blood, tears and conjunctival cells collected from 7 RED patient groups. The RESTORE VISION Consortium know multiple putative genes and proteins involved in the REDs and/or affected by the drugs to be tested in RED models. These will be analyzed in patient samples from the 7 REDs to see if they are 1) expressed at all; 2) differ in expression between patient and control group and 3) are correlated with clinical endpoints and/or symptoms of REDs. The 7 REDs under investigation are briefly explained as follows: 1. AAK: genetic progressive limbal stem cell degeneration leading to corneal neovascularization, inflammation, recurrent erosions, chronic pain and vision loss. 2. OCP: autoimmune scarring of the conjunctiva leads to deficient wound healing, inflammation, scarring, blindness and pain. 3. EEC Syndrome: Ectodermal Dysplasia causes pathological corneal scarring and blindness. 4. NK: involves a corneal nerve deficit leading to reduction or loss of corneal sensitivity, impaired wound healing, corneal ulceration and loss of vision. 5. LSCD: acquired or hereditary stem cell deficiency inducing epithelial breakdown, neovascularization, scarring and inflammation leading to decreased vision, tearing and pain. 6. oGvHD: a severe side-effect of successful bone-marrow transplantation leads to painful and blinding ocular surface inflammation, neovascularization and delayed wound healing. 7. CN: in high-risk transplantation, pathologic inflammation, corneal blood and lymphatic vessels are key risk factors for high-risk corneal graft failure, leading to graft rejection and blindness.