9 Supply of non-clinical ocular tissue from a tissue and eye services research tissue bank.

Introduction: NHS Blood and Transplant Tissue and Eye Services (TES) is a human multi-tissue, tissue bank supplying tissue for transplant to surgeons throughout the UK. In addition, TES provides a service to scientists, clinicians and tissue bankers by providing a range of non-clinical tissue for research, training and education purposes. A large proportion of the non-clinical tissues supplied is ocular tissue ranging from whole eyes, to corneas, conjunctiva, lens and posterior segments remaining after the cornea is excised.

3 Emergency salvage of time expired clinical corneas during the COVID-19 pandemic.

Introduction: Corneas for clinical use can be stored for a maximum of 28 days in organ culture medium after death. At the beginning of the COVID-19 pandemic in 2020 it became apparent that; a rare situation was arising in that clinical operations were being cancelled and that there would be a surplus of "clinical grade" corneas. Consequently, when the corneas reached the end of the storage period, if the tissue had appropriate consent, they were transferred to the Research Tissue Bank (RTB).

29 Production of ultra-thin decellularised dermis to treat severe ocular diseases.

Introduction: The ocular surface may be damaged by several ocular conditions such as chemical trauma, infection, neoplasia or autoimmune disease causing a loss of tissue and function leading to a painful loss of vision. Tissue regeneration is needed to re-establish homeostasis of the ocular surface and to preserve vision. Present replacement strategies have limitations ranging from availability of the same type of tissue to long-term stability.

26 Development of human amniotic membrane products for regenerative medicine applications.

Introduction: Human amniotic membrane (HAM) has important biological properties that make this tissue an ideal substrate for regenerative medicine applications, including treatment of ocular diseases and wound healing. NHSBT can successfully decellularise HAM for promoting enhancement of limbal stem cell expansion in vitro more efficiently than the cellular HAM. In this study we present new formulations of decellularised HAM as freeze-dried powder and derived natural hydrogel.

A single cell atlas of human cornea that defines its development, limbal progenitor cells and their interactions with the immune cells.

Purpose: Single cell (sc) analyses of key embryonic, fetal and adult stages were performed to generate a comprehensive single cell atlas of all the corneal and adjacent conjunctival cell types from development to adulthood.

Methods: Four human adult and seventeen embryonic and fetal corneas from 10 to 21 post conception week (PCW) specimens were dissociated to single cells and subjected to scRNA- and/or ATAC-Seq using the 10x Genomics platform. These were embedded using Uniform Manifold Approximation and Projection (UMAP) and clustered using Seurat graph-based clustering.

Co-expression of SARS-CoV-2 entry genes in the superficial adult human conjunctival, limbal and corneal epithelium suggests an additional route of entry via the ocular surface.

Purpose: The high infection rate of SARS-CoV-2 necessitates the need for multiple studies identifying the molecular mechanisms that facilitate the viral entry and propagation. Currently the potential extra-respiratory transmission routes of SARS-CoV-2 remain unclear.

Methods: Using single-cell RNA Seq and ATAC-Seq datasets and immunohistochemical analysis, we investigated SARS-CoV-2 tropism in the embryonic, fetal and adult human ocular surface.