The role of collagen in co-cultures of human normal corneal and conjunctival cells

Background: Intermediate interactions between corneal and conjunctival epithelial cells play an important role in the process of correct vision. The goal of this paper was to establish whether the presence or absence of collagen type I changes paracrine interactions between corneal and conjunctival epithelial cells. Material and methods: Cultures of human corneal and conjunctival epithelial cells were used in the study. The ELISA quantitative analysis of interleukin 1β (IL-1β), interleukin 6 (IL-6), urokinase-type plasminogen activator (uPA), and uPA receptor (uPAR), assessment of the type of interactions between cells, as well as correlations between tested parameters were performed. Results: The presence of collagen type I changed the quantitative production of IL-1β and IL-6 by the examined cells in the co-culture system. It did not affect the level of released uPA and uPAR. The presence or absence of collagen also changed the relationship between the cells, which were evaluated in relation to changes in the level of released cytokines. Conclusions: Different levels of collagen type I constituting a component of extracellular matrix proteins significantly affect and regulate the indirect interactions between human corneal and conjunctival epithelial cells.