Effects of eye drops containing a mixture of 3% diquafosol sodium and tocopherol acetate (vitamin E) on the ocular surface of murine dry eye.
Cutaneous and ocular toxicology
PURPOSE:To investigate the efficacy of topical application of 3% diquafosol sodium (DQS) and tocopherol (TCP) acetate mixtures in a mouse model of experimental dry eye (EDE). METHODS:After exposure to desiccating stress for 5 days, eye drops consisting of 3% DQS alone, 0.01% TCP alone, or 3% DQS and 0.005% or 0.01% TCP mixture were applied for the treatment of EDE. Tear volume, tear film break-up time (TBUT), corneal fluorescein staining scores (CFSS), and tear film lipid layer grades (TFLLG) were measured at 0, 5 and 10 days after treatment. The 2',7'-dichlorodihydrofluorescein diacetate assay (DCFDA) for reactive oxygen species (ROS) production, enzyme-linked immunosorbent assay (ELISA) for malondialdehyde (MDA), and flow cytometry for CD4 + interferon (IFN)-γ+ T cells were evaluated on the ocular surface at 10 days after treatment. In addition, levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and chemokine CC motif ligand 4 (CCL4) in the conjunctiva were measured using a multiplex immunobead assay, and conjunctival goblet cells were counted by periodic acid-Schiff staining at 10 days after treatment. RESULTS:Both the TCP mixture groups indicated a significant improvement in TBUT, ROS production, and MDA concentrations compared to those in the DQS alone group. Furthermore, the 0.01% TCP mixture group also showed higher tear film lipid layer grades and conjunctival goblet cell density and lower corneal fluorescein staining scores, number of CD4 + IFN-γ+ T cells, and levels of TNF-α, IL-1β, and CCL4 than the DQS alone group ( < 0.05). CONCLUSIONS:Application of eye drops containing the mixture of DQS and TCP could stabilize the tear film lipid layer, improve TBUT and corneal epithelial damages, decrease ROS production, inflammatory molecules, and T cells, and increase conjunctival goblet cell density on the ocular surface. Topical DQS and TCP mixtures may have a greater therapeutic effect on clinical signs, oxidative damage, and inflammation of dry eye than DQS eye drops.
Impact of Diquafosol Ophthalmic Solution on Tear Film and Dry Eye Symptom in Type 2 Diabetic Dry Eye: A Pilot Study.
Journal of ocular pharmacology and therapeutics : the official journal of the Association for Ocular Pharmacology and Therapeutics
Diquafosol ophthalmic solution (DQS) stimulates P2Y2 receptors on the ocular surface, which enhances mucin secretion from goblet cells. Therefore, tear film stability and hydration of the ocular surface can be achieved independent from lacrimal gland function. This prospective, open-label pilot study included 60 eyes of 30 diabetic patients diagnosed with dry eye disease (DED) and were randomly assigned to either DQS ( = 30 eyes) or hyaluronate (HA) group ( = 30 eyes). Participants in the DQS group received 3% diquafosol ophthalmic solution, whereas HA group received 0.1% sodium HA preservative-free artificial tears. The dosage for both drugs was 1 drop, 6 times per day for 4 weeks. Tear film lipid layer (TFLL), noninvasive breakup time (NITBUT), corneoconjunctival staining (CS) score, meibomian gland (MG), conjunctival hyperemia [redness score (RS)], ocular surface disease index (OSDI) was assessed and compared at baseline, day 14, and day 28. Comparing baseline and day 28 measurements revealed that both groups found significant improvements in NITBUT, CS, MG quality, MG expressibility, and OSDI scores significantly ( < 0.05), in addition TFLL improvements were only found in the DQS group. At day 28, the magnitude of change in mean NITBUT was 1.74 (DQS) versus 0.31 (HA), 1.16 (DQS) versus 0.37 (HA) point grade reduction in corneoconjunctival staining score and 9.80 (DQS) versus 4.80 (HA) point grade in mean OSDI score. Three percent diquafosol ophthalmic solution treatment demonstrated the ability to improve the tear film dry eye parameters and clinically reduced sign and symptoms of DED in diabetic dry eye patients. Clinical Trials.gov ID: NCT04980144.
Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium.
Sun Yi-Chen,Hung Kai-Feng,Li Tzu-Yun,Chang Yu-An,Yeh Po-Ting,Hu Fung-Rong
Investigative ophthalmology & visual science
Purpose:To determine the role of transmembrane mucins in blocking fluorescein ingress to the corneal epithelium and its deficiency in contributing to corneal fluorescein punctate staining. Methods:A dry eye model was established by extirpating lacrimal and Harderian glands in rabbits to correlate the expression of mucins with fluorescein-stained areas on the corneal button using immunofluorescence. Expression of transmembrane mucins was promoted in human corneal epithelial cells (HCECs) by culturing with the mucin-promoting medium (MPM) or diquafosol treatment. Conversely, the expression of mucins was downregulated by knockdown with short hairpin RNA. The role of mucin1 extracellular domain in fluorescein ingress was further verified by overexpression of N-terminally truncated mucin1 in HCECs. Results:In the rabbit dry eye model, the expression level of mucin1 was significantly decreased in superficial corneal epithelial cells where fluorescein punctate staining was observed. Upregulation of mucin1 and mucin16 in HCECs promoted by MPM or by diquafosol treatment impeded intracellular fluorescein ingress. Downregulation of mucin1 and mucin16 enhanced fluorescence ingress in HCECs after fluorescein staining. Overexpression of truncated mucin1 did not alter the fluorescein intensity of fluorescein-stained HCECs, supporting the notion that the ability of mucin1 to block fluorescein ingress was primarily mediated by its extracellular domain. Minimal inherent expression of mucin16 in the rabbit cornea limited the validation of its role in blocking fluorescein ingress in vivo. Conclusion:Transmembrane mucin1 blocks fluorescein ingress in the corneal epithelium, explaining how fluorescein staining is positive when the level of transmembrane mucins is disturbed in dry eyes.