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Ashley Woodward, Michelle Senchyna, Manfred Franke, Mark Holdbrook, Pablo Argueso; Effect of Intranasal Neurostimulation on Tear Protein Content in Patients With Dry Eye. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2673.
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© ARVO (1962-2015); The Authors (2016-present)
The lacrimal gland participates in the formation of the tear film by secreting a complex mixture of proteins, including lysozyme and lactoferrin, with critical roles in the protection against environmental insult and the maintenance of ocular surface homeostasis. The Intranasal Tear Neurostimulator (ITN) delivers a small electrical current to sensory neurons of the nasal cavity that stimulate the nasolacrimal reflex and induce tear production. The purpose of this study was to determine tear protein content following acute use of the ITN in patients with dry eye.
Fifty-five dry eye patients were enrolled in a single-arm study. Subjects used the ITN for approximately 3 minutes. Tear samples (up to 10 μl) were collected using microcapillary tubes prior to and 5 minutes after use of the ITN. The total protein concentration in each sample was determined using the micro-bicinchoninic acid protein assay. Tear proteins were separated by SDS-PAGE followed by Western blotting using antibodies specific to lysozyme and lactoferrin. Binding was detected using chemiluminescence and quantified by densitometry. A margin of 20% of the pre-stimulation mean was used to evaluate the equivalence between pre- and post-stimulation.
Mean pre- and post-stimulation total protein concentrations were 12.6±5.0 μg/μl and 11.8±4.0 μg/μl respectively. The 95% CI [-2.11, 0.58], of the mean difference in total protein concentration (-0.76±4.85 μg/μl), fell within the equivalence margin. By immunoblot, lysozyme and lactoferrin were found in all the tear samples primarily as a single band. The 95% CI [-0.02, 0.09], of the mean difference in relative lysozyme levels (-0.04±0.19), and the 95% CI [0.005, 0.22], of the mean difference in relative lactoferrin levels (0.11±0.37), both fell within the equivalence margins.
These results suggest that sensory neural stimulation of the nasal cavity in dry eye patients promotes release of protein from secretory granules in the lacrimal gland.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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