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Purpose: The purpose of this study was to study the osmoprotective and bioprotective effect of trehalose 3% + carboxymethylcellulose (CMC) 0.5% during desiccation conditions. Materials and Methods: Normal human conjunctival epithelial cells (IOBA) were exposed to (1) culture media (control); (2) CMC 0.5% + glycerin 0. 9% + polyethylene glycol 400 0.25% (vehicle); and (3) vehicle + trehalose 3% (trehalose). Cells were treated for 1 h and then exposed to desiccating conditions. Metabolic activity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell viability by trypan blue. Trehalose water retention capability was assessed by a gravimetric analysis. Results: Metabolic activity was maintained during the first 30 min under desiccating conditions with no differences found between groups. After 45 min, metabolic activity decreased both in the control group and the vehicle group, while the trehalose group maintained activity values. Cell viability of the trehalose group was maintained throughout time and was statistically superior to those of the control and the vehicle groups at all evaluated times (P < 0.01). The retention time 20-RT20 - (20% of water retention) was reached at 8 min in the control group, 10 min in the vehicle group, and 15 min in the trehalose group. Conclusions: The addition of 3% trehalose prolonged cell viability and extended water retention time in high-dryness environmental conditions. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the cytotoxicity of a new Latanoprost Benzalkonium chloride (BAK)‐free nanoemulsion and to compare it with a Latanoprost solution containing BAK. Methods: Normal Human Conjunctival epithelial cells (IOBA‐NHC) were incubated for 15, 30, and 60 minutes with 1:6 dilutions of either latanoprost solution containing BAK (LSc), (latanoprost 0.005%, BAK 0.02%, Xalatan, Pfizer) or latanoprost nanoemulsion (LNe), (latanoprost 0.005%, potassium sorbate 0.18%; Louten Emulsion, POEN). Cytotoxicity was determined by MTT assay. Cell death was measured by flow cytometry using annexin V‐FITC and propidium iodide. Results: Cytotoxicity evaluation: the values of cell viability and proliferation obtained from cells exposed to LNe were between 80 and 90% relative to control group, whereas values obtained from cells exposed to LSc were around 30% relative to control group at all study times (p < 0.05 at 15 and 30 minutes; p < 0.01 at 60 minutes). Cell death evaluation: the percentage of viability was significantly lower in cells exposed to LSc compared with those incubated with LNe at all study times (p < 0.05 at 15 and 30 minutes; p < 0.01 at 60 minutes). Viability of cells exposed to LNe was higher than 90% at all study times, whereas there was a time‐dependent decrease in cells exposed to Lsc. The percentage of viable cells in the LNe group was comparable to the viability of control group (93.1%) at all study times. No statistical differences between groups reached in early apoptotic cells. A significant increase of late apoptosis and necrosis cells were observed at all study times for those incubated with Lsc (p < 0.05; p < 0.01 at 30 and 60 minutes). Conclusions: The new latanoprost nanoemulsion is significantly less cytotoxic on human conjunctival cells than LSc. It suggests that the new formulation could be gentler on the eye surface than currently available BAK preserved latanoprost solutions, with levels of cytotoxicity equivalent to control. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the effect of sodium hyaluronate (SH) on benzalkonium chloride (BAK)-induced toxicity in the ocular surface epithelium and corneal nerves., Methods: Ocular surface epithelial cells from Balb/c mice were cultured with 0.1% to 0.4% SH and 0.001% to 0.01% BAK and their metabolic activity, viability, and wound repair capacity were assessed in vitro. Following a controlled corneal wound, re-epithelialization and recovery of epithelial barrier function and mechanosensitivity were measured in Balb/c mice treated with 0.4% SH 3 times/day and 0.01% BAK twice daily for 3 weeks. Nerve morphology was assessed by confocal microscopy of corneal whole mounts., Results: Whereas BAK exposure reduced metabolic activity, viability, and wound repair ability of ocular epithelial cells in vitro, pretreatment with SH ameliorated BAK toxicity in a concentration-dependent manner. The highest SH concentration partially reversed the effects of 0.01% BAK in vitro and increased the corneal healing rate of BAK-exposed mice. Although all corneal wounds closed after 4 days, continuous SH treatment improved corneal barrier dysfunction 18 days after wounding and accelerated the recovery of corneal mechanical sensitivity to baseline levels in BAK-exposed mice. SH treatment also increased corneal nerve density in the wounded area after 3 weeks., Conclusions: SH mitigates BAK-associated ocular epithelial and neurotoxicity in a concentration-dependent manner., Translational Relevance: Commercially available, high-concentration SH formulations may have added benefits in treating BAK-associated ocular surface toxicity.