Eyelid vascular changes in a sclerodermatous GVHD mouse model

Abstract

Purpose : Lymphocytes squeeze through blood vessels when they infiltrate into peripheral tissues. Therefore, blood vessels can be the first target of lymphocytes when graft-versus-host disease (GVHD) occurs. To investigate the vascular changes in meibomian glands, we examined blood vessels in the eyelid of mice with GVHD.

Methods : We used an established ocular GVHD mouse model (He J, Yamane Y,et al. Cornea, 2017). Eyelids from allogeneic bone marrow transplantation (allo-BMT) recipient mice and syngeneic BMT (syn-BMT) recipient mice were collected 4 weeks after BMT. The expression of CD31, CD133, VEGFR2 and VE-cadherin in endothelia, and α-SMA in pericytes in meibomian glands was examined. The ultrastructure of meibomian glands was observed by transmission electron microscopy.

Results : The VEGFR2 and α-SMA positive areas (Mean ± SD μm²/field) were significantly increased in eyelids from allo-BMT recipients (4388 ± 1739, n=4 and 1742 ± 871.9, n=6 separately) compare to syn-BMT recipients (1467 ± 334.2, n=4 and 866.4 ± 239.9, n=8, p=0.0286 and 0.0293). The number of CD133 positive cells per field was significantly increased in the GVHD group (13.00 ± 1.581, n = 4) compare to the controls (1.70 ± 0.570, n = 5, p = 0.0159). The CD31 expression in endothelia was slightly increased in the GVHD samples in comparison with the controls. Some vessels in the allo-BMT recipients expressed little to no VE-cadherin. This phenomenon was indicative of neovascularization induced by GVHD, given that such events were not seen in the syn-BMT recipients. Enlarged, tortuous and branching vessels were found in the GVHD group, whereas they were rather thin and straight in the control group. While abnormal fenestrae were observed in endothelia in the mice with GVHD, it was not the case with those without GVHD.

Conclusions : A series of our murine experiments indicated that GVHD could cause eyelid vascular changes including endothelial damage, loss of endothelial junction, pericyte activation and neovascularization. These events presumably arose from immune cell infiltration into meibomian glands and the resultant fibrosis and ischemia.

This is a 2020 ARVO Annual Meeting abstract.