Vasoactive Intestinal Peptide Promotes Corneal Allograft Survival

Abstract

Corneal transplantation is the most prevalent form of tissue transplantation. The success of corneal transplantation mainly relies on the integrity of corneal endothelial cells (CEnCs), which maintain graft transparency. CEnC density decreases significantly after corneal transplantation even in the absence of graft rejection. To date, different strategies have been used to enhance CEnC survival. The neuropeptide vasoactive intestinal peptide (VIP) improves CEnC integrity during donor cornea tissue storage and protects CEnCs against oxidative stress-induced apoptosis. However, little is known about the effect of exogenous administration of VIP on corneal transplant outcomes. We found that VIP significantly accelerates endothelial wound closure and suppresses interferon-γ- and tumor necrosis factor-α-induced CEnC apoptosis in vitro in a dose-dependent manner. In addition, we found that intracameral administration of VIP to mice undergoing syngeneic corneal transplantation with endothelial injury increases CEnC density and decreases graft opacity scores. Finally, using a mouse model of allogeneic corneal transplantation, we found for the first time that treatment with VIP significantly suppresses posttransplantation CEnC loss and improves corneal allograft survival.

Regulatory T cells promote corneal endothelial cell survival following transplantation via interleukin-10

“…47 All cell types were harvested from draining cervical lymph nodes ipsilateral to the grafted eye 14 days after corneal transplantation, and purified using magnetic cell sorting (CD4 + CD25 + Regulatory T cell Isolation kit, Miltenyi Biotec., Auburn, CA) as per the manufacturer's instructions. 47 All cell types were harvested from draining cervical lymph nodes ipsilateral to the grafted eye 14 days after corneal transplantation, and purified using magnetic cell sorting (CD4 + CD25 + Regulatory T cell Isolation kit, Miltenyi Biotec., Auburn, CA) as per the manufacturer's instructions.…”

“…47 A masked observer was responsible for capturing images by confocal microscopy and counting cells using the ImageJ software. ZO-1 staining (rather than DAPI) was used to determine live CEnCs to avoid staining of other cell types such as immune cells and keratocytes, as described previously.…”

“…In order to evaluate the cytoprotective function of Tregs derived from low-risk or high-risk hosts in the context of effector T cell-mediated and IFN-γ and tumor necrosis factor alpha (TNF-α)-induced CEnC death, a cornea-in-the-cup assay was used. 47 To control for the possibility of Tregs acting as a sink 38,48,49 for inflammatory cytokines, Tregs derived from low-risk or high-risk graft recipients were stimulated in anti-CD3ε precoated plates (10 μg/mL; Biolegend, LEAF TM purified anti-mouse CD3ε, clone 145-2C11, for…”

“…ZO-1 staining (rather than DAPI) was used to determine live CEnCs to avoid staining of other cell types such as immune cells and keratocytes, as described previously. 47 A masked observer was responsible for capturing images by confocal microscopy and counting cells using the ImageJ software.…”

Recent advances of exosomes in immune-mediated eye diseases

“…Corneal transplantation is the most prevalently performed type of tissue grafting globally. To enhance corneal graft survival, considerable efforts have been devoted to building effective strategies [77]. Although cornea as an avascular transparent tissue enjoys the relative privilege of immunity, the major cause of corneal graft failure reported is allogeneic rejection, which is ascribed to the adaptive immune response initiated through recognition of donor MHC antigens by recipient T cells after transplantation [78,79].…”