Randomized Controlled Crossover Trial Comparing the Impact of Sham or Intranasal Tear Neurostimulation on Conjunctival Goblet Cell Degranulation

Abstract

Purpose: The aim of the study was to investigate the effects of the Allergan Intranasal Tear Neurostimulator (ITN) on conjunctival goblet cell (GC) degranulation.

Design: A randomized, double-masked, placebo-controlled crossover trial.

Methods: A total of 15 subjects (5 normal and 10 dry eye) were enrolled in a 3-visit study consisting of 1 screening and 2 separate randomized-masked ITN treatments (sham extranasal or intranasal). Tear meniscus height (TMH) was measured by anterior segment optical coherence tomography before and after applications. Impression cytology (IC) was taken from the bulbar conjunctiva of the right eye for periodic acid-Schiff staining and from the left eye for MUC5AC mucin immunostaining at baseline and after each treatment. The ratio of degranulated to nondegranulated GCs was measured as a marker of secretion.

Results: In all participants, both inferior bulbar (IB) and temporal bulbar (TB) cytology specimens stained for MUC5AC revealed a significantly higher ratio of degranulated to nondegranulated GCs after the ITN (IB: 2.28 ± 1.27 and TB: 1.81 ± 1.01) compared to baseline (IB: 0.56 ± 0.55, P = .015) (TB: 0.56 ± 0.32, P = .003) and extranasal sham application (IB: 0.37 ± 0.29, P = .001) (TB: 0.39 ± 0.33, P = .001). When the same analysis was repeated in the dry eye or control groups, the ratio was significantly higher after ITN than the baseline ratio and ratio after extranasal application in both groups (P < .05). Moreover, although control subjects had a higher ratio of degranulated to nondegranulated GCs at baseline (0.75 ± 0.52) compared with the dry eye group (0.41 ± 0.27), the ratio became slightly higher in dry eye (2.04 ± 1.12 vs 1.99 ± 1.21 in control) after the ITN application. There was no significant difference between the IB or TB conjunctiva locations in terms of the effectiveness of the ITN application on conjunctival goblet cell secretory response.

Conclusions: These preliminary results document that the Allergan ITN can stimulate degranulation of goblet cells in the conjunctiva, which is a promising new approach for the management of dry eye.

Trial registration: ClinicalTrials.gov NCT02385292.

Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

The intranasal neurostimulator used in this study to evaluate goblet cell degranulation and aqueous tear production consists of four distinct parts: 1) A reusable base unit, which produces the electrical stimulation waveform, 2) A disposable tip assembly that inserts into the nasal cavity and stimulates the target intranasal tissue, 3) A reusable cover to protect the tip assembly, 4) A charger, which recharges the battery inside the base unit.

Figure 2

To deliver the electrical stimulus from the device, subjects were instructed to place the tips of the Allergan Intranasal Tear Neurostimulator (ITN) into both nostrils simultaneously towards the top and front of the nose for the intranasal application (Left). Extranasal stimulation was performed as a control. In this case, subjects were instructed to place the tips of the ITN on the lower part of the nose skin (one tip on each side) and apply the stimulus (Right).

Figure 3

Image of periodic acid-Schiff (PAS)-stained impression cytology specimen showing degranulated (*) and non-degranulated (**) goblet cell types.

Figure 4

Image of mucin 5AC (MUC5AC) stained impression cytology specimen showing degranulated (*) and non-degranulated (**) goblet cells.

Figure 5

Means and 95% confidence intervals (CIs) for tear meniscus height (TMH) and tear meniscus area (TMA) values before and after extra- and intranasal application in normal subjects and dry eye patients

Figure 6

Optical coherence tomography (OCT) images showing a change in tear meniscus height in a subject with Sjögren’s Syndrome aqueous tear deficiency (top: OD, bottom: OS) before and after the intranasal application (right).

Figure 7

An example of mucin 5AC (MUC5AC) stained impression cytology taken after extranasal and intranasal neurostimulation (x40 magnification). In the left image, all goblet cells appear to be in a non-degranulated form with intact boundaries and packaged MUC5AC stained mucous granules inside the cells. In contrast, most of the goblet cells showed a degranulation pattern with disruption of cellular morphology and exocytosis of MUC5AC stained mucous granules and mucin outside the cells.

Figure 8

Ratio of degranulated:non-degranulated goblet cells in the inferior and temporal bulbar conjunctiva of dry eye patients in mucin 5AC (MUC5AC) stained impression cytology membranes.