In vitro biocompatibility assessment of multipurpose contact lens solutions: effects on human corneal epithelial viability and barrier function.

PURPOSE: To explore the in vitro effects of multipurpose contact lens solutions (MPSs) on corneal epithelial barrier function and viability. METHODS: Human corneal epithelial cells (HCEpiC) were exposed to 50% MPSs A-G. Viability was determined using metabolic activity, protease release and caspase assays. Barrier function was evaluated using immunostaining for the tight junction protein zonnula occludens-1 (ZO-1) and resistance measurements. RESULTS: MPS A and G did not affect HCEpiC monolayer viability after 2 h, while MPSs B-F significantly decreased viability. There was a significant decrease in stratified HCEpiC viability after exposure to MPSs B-E for 2 h, while there was no effect of MPS A. After exposure of HCEpiC monolayers to MPS A, F or G for 30 min, ZO-1 staining appeared similar to control. HCEpiC exposed to MPSs B and C demonstrated tight junction breakdown. There was no significant change in HCEpiC monolayer resistance after exposure to MPS A or F for 2 h, while MPSs B-E and G reduced resistance. After exposure to MPS A-E, stratified HCEpiC resistance was significantly decreased after 2 or 4 h. The decrease in resistance was significantly less with MPS A as compared to the other MPSs. CONCLUSIONS: MPSs caused varying modifications to cell viability and barrier function in monolayer and stratified HCEpiC. MPS A did not alter monolayer HCEpiC viability or barrier function, while MPSs B-G caused significant decreases of at least one parameter. Furthermore, MPS A had significantly less effect than MPSs B-E on viability and barrier function of stratified HCEpiC.

Effect of a novel multipurpose contact lens solution on human corneal epithelial barrier function.

PURPOSE: To explore the effect of a novel multipurpose contact lens solution (MPS) on the junction protein distribution and barrier function of cultured human corneal epithelial cell monolayers. METHODS: Cultured human corneal epithelial cells (HCEpiC) were exposed to a novel MPS (MPS A; Biotrue™ multi-purpose solution, Bausch & Lomb Incorporated) at 50%, 75% and 100% for 10 or 30 min. Four commercially available MPS products, MPS B (AQuify, Ciba Vision), MPS C (COMPLETE MPS Easy Rub, AMO), MPS D (OPTI-FREE Express, Alcon) and MPS E (OPTI-FREE RepleniSH, Alcon) were tested in parallel. Tight junction structure and integrity were evaluated by confocal microscopy using ZO-1 antibody and scanning microscopy (SEM). Quantitative evaluation of MPSs on epithelial barrier function was determined by measuring transepithelial electrical resistance (TEER) across HCEpiC grown on Transwell Clear permeable supports and on electric cell-substrate impedance sensing (ECIS) electrode arrays. RESULTS: Overall after exposure to the three concentrations (50%, 75%, and 100%) of MPS A, ZO-1 distribution and fluorescent intensity on the cell surface appeared similar to the media control with continuous tight junctions and clear intercellular junctions. At all measured time points after exposure to MPS A (50% or 75%) there was also no effect on the TEER using both resistance methodologies, and SEM showed that MPS A appeared similar to the Hank's balanced salt solution (HBSS) control. In cells exposed to MPS D there was a dose-dependent change in the distribution of ZO-1, some cell detachment, and a decrease in monolayer resistance at all time points measured. Ultrastructurally, MPS D caused gross changes, including damage to cell junctions and plasma membranes. To a lesser extent, the remaining three commercial MPS products demonstrated some effects on tight junction ZO-1 distribution and/or TEER. CONCLUSIONS: Based on the in vitro measurements of tight junction protein expression, monolayer integrity, and transepithelial electrical resistance, the novel multipurpose contact lens solution (MPS A) did not alter corneal barrier function as compared to media, PBS or HBSS control. Clinical significance of the observed differences in epithelial barrier function among the MPSs tested needs further investigation.

A unique mosaic in the visual cortex of the reeler mutant mouse.

Numerous studies have revealed abnormal cytoarchitectonics in the reeler mouse brain. In the present study, acetylcholinesterase (AChE) histochemistry has revealed a distinctive mosaic within the occipital cortex of the reeler mouse. The mosaic does not appear until after the second postnatal week, perhaps in association with eye opening. AChE staining in the visual cortex of normal littermates does not exhibit a mosaic pattern, but rather, is present within bands or laminae. The AChE mosaic in reeler persists into adulthood. Immunocytochemical staining of the tenascin glycoprotein, an astrocyte-derived extracellular matrix molecule that is concentrated in boundaries around emerging functional patterns in the CNS, reveals a boundary-mosaic pattern in the first postnatal week. Dil axonal tracing in normal versus reeler mice indicates that the thalamocortical projections may also be associated with the AChE mosaic. The observation that a mosaic is unique to the occipital cortex of reeler mice suggests that it may evolve through abnormal cell and molecular interactions in the mutant cortex that normally lead to the development of functional visual representations.