Abstract
Purpose:
We have reported that dendritic cells (DCs) migrate into the central area in infected cornea. Certain cytokines induced by interaction between corneal epithelium and DCs accelerate the migration of DCs from limbus to the central to protect against infection (ARVO 2012). Diabetes mellitus (DM) patients often suffer from the ocular surface complications and the glucose level in the tear film is higher than healthy people. In this study we investigated the effect of high glucose on the interaction of DCs and corneal epithelial cells.
Methods:
All experiments were performed under the approval of the Ethical Committee of Yamagata University Faculty of Medicine. Human corneal epithelial cells (HCE cells) were cultured with normal, high glucose, and high osmolarity growth medium for 3 days. Immature DCs were isolated from peripheral blood of the healthy donors (n = 10). Supernatants were collected at 1.5, 3 and 6 hours from 4 treatment groups: (A) HCE cells, (B) HCE cells stimulated with LPS, (C) HCE cells co-cultured with DCs, and (D) HCE cells co-cultured with DCs and stimulated with LPS. The levels of chemotactic factors of DCs, including IL-6, activin A, and TNF-α in the supernatants were measured by ELISA assay.
Results:
IL-6 was detected in all samples of supernatants. The elevation of IL-6 level occurred in a time-dependent manner except in the supernatant of untreated HCE cells (group A). Activin A was detected in all supernatants.The elevation of activin A level was time dependent only in the supernatant of HCE cells stimulated with LPS (group B). An elevated level of TNF-α was observed only in the supernatant of group D, HCE cells co-cultured with DCs and stimulated with LPS and its level increased in a time-dependent manner. High glucose and high osmolarity state didn't affect on the levels of IL-6 and activin A. The level of TNF-α was lower in the high glucose medium (1.5h: 33.04, 6h: 422.18 pg/ml) and the high osmorality state (1.5h: 31.57, 6h: 432.05 pg/ml) in comparison with the normal growth medium (1.5h: 53.77, 6h: 832.5 pg/ml). There were no significant differences in high glucose and high osmolarity states.
Conclusions:
High glucose and high osmolarity in the growth medium affected the TNF-α induced by the interaction between HCE cells and DCs. High osmolarity caused by high glucose state in the tear film may affect ocular surface of DM patients.
Keywords: 482 cornea: epithelium •
490 cytokines/chemokines •
557 inflammation