Conjunctival cell viability and apoptosis after one month of treatment with Thealoz® in dry eye subjects

Abstract

Purpose: to analyze the viability and apoptosis of conjunctival cells after 1 month of treatment with Thealoz® (threalose 3%) compared with control (saline solution 0.9%) in dry eye subjects.

Methods: 29 dry eye subjects were analyzed from a total of 50 patients foreseen for the study. After a wash-out period of 1 week (minimum 3, maximum 8 instillations per day of saline solution 0.9%), they were randomly assigned to use Thealoz® or saline solution 0.9% for 1 month, 6 times per day. Brush cytology was performed in the conjunctival inferior fornix before (V1) and after (V2) four weeks of treatment. Cell viability and apoptosis were analyzed by flow cytometry. Lissamine green conjunctival staining was performed and was graded in a 0-4 scale (Oxford scale). Change of variables was defined as the rate of change at V2 respect to the initial value (V1).

Results: In the group treated with Thealoz® it was found an increase in the percentage of viable cells after the treatment (V1: 37.41±27.57%; V2: 49.85±28.01), and a decrease in the control group (V1: 47.14±25.67%; V2: 46.61±21.57), these changes were not significant. Percentage of cells in early apoptosis decreased in Thealoz® (V1: 25.75±12.72, V2: 22.83±15.73) and in control group (V1: 22.06±9.84, V2: 19.78±7.52), but changes were not significant. Percentage of cells in late apoptosis (significant change) decreased in the Thealoz® group (V1: 33.09±20.76, V2: 24.62±14.12), and increased (non significant change) for the control group (V1: 28.73±15.65, V2: 32.19±15.81). A significant change in both groups was found in the percentage of dead cells (Thealoz®, V1: 3.75±2.24, V2: 2.72±2.71; control, V1: 2.05±2.03, V2: 1.42±0.95). A significant change was found in conjunctival staining, in the Thealoz® group (V1: median: 1, 95% confidence interval -CI-:1,2; V2: median: 0, 95% CI:0,1 ), and this change was not significant for the control group (V1: median: 1, 95% confidence interval -CI-:1,2; V2: median: 1, 95% CI:1,2 ).

Conclusions: This intermediate analysis results show positive tendencies and significant changes on the way that Thealoz® seems to protect the conjunctival epithelial cells in dry eye subjects, probably by rescuing them from apoptosis. This finding seems to have a clinical expression in the decrease of conjunctival staining. New analysis to confirm positive tendencies will be done at the end of the study.

Keywords: 426 apoptosis/cell death • 482 cornea: epithelium • 486 cornea: tears/tear film/dry eye