Phase 3 Clinical Trial Comparing the Safety and Efficacy of Netarsudil to Ripasudil in Patients with Primary Open-Angle Glaucoma or Ocular Hypertension: Japan Rho Kinase Elevated Intraocular Pressure Treatment Trial (J-ROCKET).

INTRODUCTION: A clinical trial evaluated ocular hypotensive efficacy and safety of netarsudil 0.02% once daily (QD) relative to ripasudil 0.4% twice daily (BID). METHODS: This was a single-masked, randomized, phase 3, superiority study. Japanese patients were randomized to either the netarsudil 0.02% group or the ripasudil 0.4% group in a 1:1 ratio and treated for 4 weeks. The primary efficacy variable was mean diurnal intraocular pressure (IOP) (average of diurnal time points at 09:00, 11:00, and 16:00) at Week 4. RESULTS: A total of 245 patients were included in the primary analysis. At Week 4, least squares (LS) mean of diurnal IOP adjusted for baseline was 15.96 and 17.71 mmHg in the netarsudil 0.02% and ripasudil 0.4% groups, respectively, demonstrating the superiority of netarsudil 0.02% QD over ripasudil 0.4% BID by a margin of - 1.74 mmHg (p < 0.0001). Mean reduction from baseline in mean diurnal IOP at Week 4 was 4.65 and 2.98 mmHg, respectively. Adverse events (AEs) occurred less frequently in netarsudil 0.02% than in ripasudil 0.4%, with the incidence of ocular AEs being 59.8% and 66.7%, respectively. The most frequently reported AE was conjunctival hyperemia in both groups, with an incidence of 54.9% and 62.6%, respectively. No serious eye-related AEs were reported. CONCLUSION: Netarsudil ophthalmic solution 0.02% dosed QD (p.m.) was well tolerated and more effective in reducing IOP than ripasudil ophthalmic solution 0.4% dosed BID. Netarsudil 0.02% QD may become an important option for the treatment of Japanese patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT). TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT04620135.

Phase 2, Randomized, Open-Label Parallel-Group Study of Two Dosing Regimens of Netarsudil for the Treatment of Corneal Edema Due to Fuchs Corneal Dystrophy.

Background: This phase 2 study evaluated the therapeutic potential of netarsudil to reduce corneal edema and to improve vision in patients with Fuchs corneal dystrophy (FCD). Methods: Patients (N = 40) with baseline central corneal thickness (CCT) of ≥600 µm and best-corrected visual acuity (BCVA) of 70-20 letters (20/40-20/400 Snellen equivalent) were randomized 1:1 to receive netarsudil once a day (QD) or twice a day (BID) for 8 weeks. Primary endpoint was mean CCT change from baseline at week 4. Results: Netarsudil QD and BID significantly reduced CCT at week 4 [mean change (standard error of mean), 28.4 (7.99) µm, P = 0.0021; and 20.1 (8.75) µm, P = 0.0335, respectively]. Five (12.5%) patients achieved complete resolution of corneal edema at week 4. BCVA improved by 3.2 (2.76) letters with QD and 1.5 (2.84) letters with BID, and 10 (25%) patients [5 with QD (P = 0.0078) and 5 with BID (P = 0.0096)] gained ≥10 letters at week 4. Improvements in CCT and vision were observed at week 2 and persisted at week 8, without significant differences between the 2 doses at any time point. Netarsudil QD significantly improved visual acuity and glare factor scores on the Visual Function and Corneal Health Status (V-FUCHS) questionnaire at weeks 4 and 8 (mean change, -0.4 to -0.3; P ≤ 0.0200). Netarsudil was well tolerated. Reticular edema developed in one (2.5%) patient with BID, which resolved with treatment discontinuation. Conclusions: Netarsudil QD led to significant reductions in corneal edema as well as improvements in vision and patient-reported symptoms of glare and visual impairment in patients with FCD. Clinical Trial Registration Number: NCT04498169.

A randomized, vehicle-controlled, Phase 2b study of two concentrations of the TRPM8 receptor agonist AR-15512 in the treatment of dry eye disease (COMET-1).

PURPOSE: Dry eye disease (DED) symptoms can negatively impact quality of life (QoL). AR-15512, a transient receptor potential melastatin 8 (TRPM8) agonist, was evaluated as a potential therapy for DED. METHODS: In a Phase 2b study, patients with DED were randomized 1:1:1 to 0.0014% AR-15512, 0.003% AR-15512, or vehicle twice daily for 12 weeks. Eligibility criteria included DED signs and symptoms of prespecified severity levels. Outcomes assessed were DED signs (Schirmer score ± anesthetic, ocular surface staining, hyperemia), symptoms (Ocular Discomfort [ODS-VAS], Symptoms Assessment iN Dry Eye [SANDE], Eye Dryness-VAS, Ocular Pain-VAS), QoL-VAS, and adverse events. Co-primary endpoints were changes from baseline in ODS-VAS and anesthetized Schirmer score at Day 28. RESULTS: 0.003% AR-15512 (n = 122) was associated with early and sustained improvements in unanesthetized Schirmer score (Days 1 and 14, p < 0.0001), as well as improvements in ocular surface staining (Days 14 and 84, p ≤ 0.0365) and hyperemia (Day 84, p < 0.0215). Statistically significant improvements in symptoms were observed for the 0.003% concentration on SANDE (Days 14, 28, and 84, p ≤ 0.0254), ODS-VAS (Day 84, p = 0.0281), Eye Dryness-VAS (Day 84, p = 0.0302), and multiple QoL measures (Days 14, 28, and 84, p < 0.05). There were no significant differences between active and vehicle groups for the co-primary endpoints. The most common adverse events were burning and stinging upon instillation. CONCLUSIONS: Although predefined co-primary study endpoints were not met, AR-15512 demonstrated statistically significant improvements in DED signs, symptoms, and disease-related QoL.

Optimization of goblet cell density quantification methods.

The purpose of this study was to develop a standardized, accurate and efficient method for estimating conjunctival goblet cell density (GCD) via optimizing sample storage conditions and quantification methods. Conjunctival impression cytology (CIC) membranes were collected from both eyes of 32 participants and were randomized to two storage durations (2-3 weeks, 6-7 weeks) and two storage container types (microcentrifuge tube, flat histology cassette). The CIC membranes were stained and subdivided into 25 areas (5 mm × 5 mm) for imaging and the GCs were counted under 200X magnification using three different methods: (1) full CIC membrane GC count of the 25 images with cell-counting software ("full"; reference method), (2) partial membrane GC count of 9 images with cell-counting software ("partial"), and (3) manual counting of the 25 images ("manual"). In all cases, GCD was determined by dividing the GC count by the counting area. The average time required for quantification was recorded to gauge efficiency. Results showed no significant difference in GC count between the two storage durations (p = 0.745) or storage container types (p = 0.552). The median (interquartile range (IQR)) time required to quantify a CIC membrane for the full, partial, and manual methods of GC counting, was 14.8(17.6), 4.6(5.2) and 5.0 (5.0) minutes, respectively. The agreement of GCD values between the full and manual methods (bias: 0.4, 95% LOA: [-4.6, 5.5]) was stronger than that comparing the full and partial methods (bias: 0.5, 95% LOA: [-18, 17]). All together, through systematic examination of key procedural variables, an optimized method for GCD quantification within 7 weeks of sample collection was outlined. Adaption of procedures described in this paper to facilitate accurate and efficient GCD quantification may serve as a valuable step in clinical trials investigating DED pathophysiology and/or novel DED treatment strategies.

Bulbar Redness and Dry Eye Disease: Comparison of a Validated Subjective Grading Scale and an Objective Automated Method.

SIGNIFICANCE: In this study, assessments of conjunctival redness were performed to evaluate whether patients with or without dry eye disease (DED) could be discriminated based on this measure. Our findings suggest that subjectively grading redness by quadrant, as opposed to automated en face measurements, may be more suitable for this purpose. PURPOSE: This study aimed to quantify bulbar redness using the validated bulbar redness (VBR) grading scale and an automated objective method (Oculus Keratograph 5M; K5M) in participants with DED and non-DED controls. METHODS: Participants with DED (Ocular Surface Disease Index score ≥20 and Oxford scale corneal staining ≥2) and controls (Ocular Surface Disease Index score ≤10 and corneal staining ≤1) attended two study visits. In part 1A of visit 1, baseline bulbar redness was graded with the VBR scale in each conjunctival quadrant of both eyes, followed by automated measurements of temporal and nasal redness with the K5M. This was immediately followed by part 1B, during which a topical vasoconstrictor was instilled into both eyes. Redness assessments were repeated 5 and 30 minutes after instillation with both instruments. Participants returned 14 days later for visit 2, where the same assessments as for visit 1A were repeated. RESULTS: Seventy-four participants (50 DED and 24 controls) completed the study. There were statistically significant differences in redness between the DED and control groups when assessed with the VBR scale (14/16 comparisons; all, P < .05), whereas no significant differences in K5M-derived redness between the DED and non-DED groups were found at any location or time point. Both subjective and objective instruments detected statistically significant reductions in redness 5 and 30 minutes after instillation of the vasoconstrictor (all, P < .01). CONCLUSIONS: Although both subjective and objective instruments were sensitive to detecting changes in redness induced by vasoconstriction, statistically significant differences in redness between DED and control groups were only found using the VBR scale.

Phase 2 Randomized Clinical Study of Netarsudil Ophthalmic Solution in Japanese Patients with Primary Open-Angle Glaucoma or Ocular Hypertension.

INTRODUCTION: Netarsudil reduces intraocular pressure (IOP) by increasing aqueous outflow through the trabecular meshwork (TM) pathway and decreasing episcleral venous pressure. The primary objective of this phase 2 study was to evaluate ocular hypotensive efficacy and safety of three netarsudil concentrations (0.01%, 0.02%, and 0.04%) relative to its placebo over 4 weeks in Japanese patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT). METHODS: Patients were randomized to one of four treatment arms, netarsudil ophthalmic solution 0.01%, 0.02%, 0.04%, or placebo, and treated once-daily (QD) in the evening (P.M.) for 4 weeks. The primary efficacy variable was mean diurnal IOP (average of diurnal time points at 9 A.M., 11 A.M., and 4 P.M.) at week 4. RESULTS: A total of 215 patients were randomized and 207 (96.3%) completed the study. The mean of mean diurnal IOP at baseline ranged from 20.28 to 21.14 mmHg across groups. At week 4, least squares (LS) mean of mean diurnal IOP adjusted for baseline was 16.53, 15.82, 16.06, and 18.94 mmHg in the netarsudil 0.01%, 0.02%, 0.04%, and placebo groups, respectively, demonstrating the superiority of netarsudil (all concentrations) over placebo. At week 4, mean reduction (mean percentage reduction) from baseline in mean diurnal IOP was 4.10 (19.8%), 4.80 (23.5%), 4.81 (23.8%), and 1.73 mmHg (8.2%), respectively, demonstrating statistically significant reductions (p < 0.0001) in all netarsudil concentrations over placebo. Adverse events (AEs) occurred in a concentration-dependent manner, and the incidence of ocular AEs was 34.5%, 42.6%, 68.6%, and 9.1% in the netarsudil 0.01%, 0.02%, 0.04%, and placebo groups, respectively. The most frequently reported AE was conjunctival hyperemia, with an incidence of 23.6%, 37.0%, 56.9%, and 1.8%, respectively. No serious AEs were reported. CONCLUSION: Netarsudil ophthalmic solutions 0.01%, 0.02%, and 0.04% dosed QD (P.M.) demonstrated superiority to placebo in terms of hypotensive effectiveness at week 4 and were found to be safe and generally well tolerated. Netarsudil 0.02% QD provided an optimal efficacy and safety profile for the treatment of Japanese patients with POAG or OHT. TRIAL REGISTRATION: NCT03844945.

Short-Term Reproducibility of MUC5AC Measurement in Human Tear Fluid.

The assessment of tear fluid components is a common and valuable approach to understanding ocular surface disease and testing the efficacy of novel therapeutic strategies. However, the interpretation and utility of the findings can be limited by changes in the composition of the tear film, particularly in studies requiring repetitive patient sampling. Here, tear samples were collected twice within a one-hour interval to evaluate the short-term reproducibility of an immunoassay aimed to measure the amount of MUC5AC mucin. We found no statistical difference in total protein or MUC5AC content between the two consecutive collections of tear fluid, although the inter-individual variability in each group was high, with coefficients of variation exceeding 30% and 50%, respectively. Scatterplots showed a significant correlation in both protein and MUC5AC following collection within a one-hour interval. These data indicate that, regardless of the high inter-individual variability, repeated collection of tear fluid within an hour interval produces reproducible intra-individual data in terms of MUC5AC mucin content, and suggest that the normal mucin composition of the tear fluid can be re-established within an hour of the initial collection.

Infrared meibography allows detection of dimensional changes in meibomian glands following intranasal neurostimulation.

PURPOSE: Patients with dry eye disease (DED) may suffer from decreased tear break-up time due to meibomian gland (MG) dysfunction. Infrared meibography (IR Meibography) uses infrared wavelength light to visualize meibomian glands in vivo. We aimed to explore the feasibility of using serial IR Meibography imaging to assess morphological changes in MGs as an indirect measure of functionality, following intranasal neurostimulation (ITN). METHODS: Fifteen DED subjects were prospectively enrolled in a single-center, single-arm study. Changes in MGs were captured using IR meibography (RTVUE-XR, Optovue, Inc. Fremont, CA, USA) on the lower eyelids before and after 3 min of ITN (TrueTear®, Allergan, Dublin, Ireland) use that delivers a microcurrent to sensory neurons of the nasal cavity. The same MGs were selected pre- and post-stimulation, and MG area and perimeter were analyzed by two masked observers. RESULTS: Mean (±SD) pre- and post-stimulation MG areas were 2,187.60 ± 635.88 µm2 and 1,933.20 ± 538.55 µm2, respectively. The mean change in area, 254.49 µm2, representing an 11.6% reduction following ITN use, was statistically significant (p = 0.001). Mean (±SD) pre- and post-stimulation MG perimeters were 235.9 ± 51.38 µm and 222.2 ± 47.72 µm, respectively. The mean change in perimeter, 13.7 µm, representing a 5.81% reduction following ITN use, was statistically significant (p = 0.012). CONCLUSIONS: Our study shows that IR meibography can be used to detect immediate changes in gland area and perimeter, an indirect measure of MG activity following intervention by ITN.

Symptom improvement in dry eye subjects following intranasal tear neurostimulation: Results of two studies utilizing a controlled adverse environment.

PURPOSE: To evaluate the safety and effectiveness of the intranasal tear neurostimulator (ITN) in improving dry eye symptoms assessed in a controlled adverse environment (CAE®). METHODS: Study 1: Multicenter, subject-masked, randomized-sequence, crossover design. Single intranasal (active) and extranasal (control) ITN administration during CAE exposure. Study 2: Single-arm, open-label design. Intranasal ITN administration ≥2 times/day for 45 days, CAE assessment at days 0 and 45. In both studies, upon CAE entry, and every 5 min thereafter, subjects assessed eye dryness score (visual analog scale, 0-100 mm; EDS-VAS), and ocular discomfort score (ODS; Ora Calibra™, 0-4), for ≈2 h. Study 1: when ODS was ≥3 at 2 consecutive timepoints, subjects applied ITN intranasally or extranasally for ≈3 min, and again when achieving the same ODS criteria in randomized sequence. Study 2: days 0 and 45, ITN was applied for ≈3 min employing the same ODS criteria as Study 1. RESULTS: Study 1: Significantly greater pre- to post-application reductions in mean [SEM] EDS (-16.5 [1.7] vs -3.1 [1.7], P < 0.0001) and ODS (-0.93 [0.08] vs -0.34 [0.08], P < 0.0001; n = 143) with intranasal vs extranasal stimulation. Study 2: On day 0 (n = 52) and day 45 (n = 48), significant pre- to post-application reductions in mean [SEM] EDS (-15.9 [2.7] and -15.2 [2.4]; P < 0.0001), and ODS (-1.3 [0.2] and -1.3 [0.1]; P < 0.0001). Few device-related adverse events were reported, none serious. CONCLUSIONS: Acute symptom relief is significant with the ITN and remains undiminished after daily use.

Characterization of tear production in subjects with dry eye disease during intranasal tear neurostimulation: Results from two pivotal clinical trials.

PURPOSE: The intranasal tear neurostimulator (ITN) activates the nasolacrimal pathway, which is involved with basal and bolus tear secretion. These studies characterized the acute and long-term effectiveness of the ITN in stimulating tear production in subjects with dry eye disease (DED). METHODS: Study 1: Randomized, double-masked, dual-controlled, 1-day crossover. Study 2: Single-arm, open-label, 180-day prospective cohort. Eligible subjects had basal unstimulated Schirmer test (with anesthesia) ≤10 mm and intranasal cotton swab-stimulated Schirmer test at least 7 mm greater in the same eye, and Ocular Surface Disease Index® ≥13 and ≥ 23, in Studies 1 and 2, respectively. Study 1: Subjects (n = 48) received three randomized test applications: active intranasal, extranasal (active control), and sham intranasal (inactive control) stimulation, 3 min/application with 1-hour minimum between applications. Primary outcome measure was the difference in Schirmer test scores during active intranasal and control applications. Study 2: Subjects (n = 97) performed intranasal neurostimulation for ≤3 min/application, 2-10 times/day. Primary outcome measure was the difference in Schirmer scores (stimulated minus unstimulated) at day 180. Both studies recorded device-related adverse events (AEs). RESULTS: Study 1: Schirmer scores (mean ±â€¯SEM) were significantly greater (p < 0.0001) with active intranasal (25.3 ±â€¯1.5 mm) vs extranasal (9.5 ±â€¯1.2 mm) and sham (9.2 ±â€¯1.1 mm) applications. Study 2: Schirmer scores were significantly greater (p < 0.0001) with ITN stimulation vs unstimulated at day 180 (17.3 ±â€¯1.3 mm vs 7.9 ±â€¯0.7 mm). No serious device-related AEs were reported in either study. CONCLUSION: The ITN was well-tolerated and effective in stimulating tear production with acute and long-term use in DED. CLINICALTRIALS. GOV IDENTIFIER: NCT02680158 and NCT02526290.

Development of a Meibomian Gland Dysfunction-Specific Symptom Questionnaire.

OBJECTIVES: The aim of this study was to develop and evaluate, using psychometric approaches, a meibomian gland dysfunction (MGD)-specific questionnaire in noncontact lens wearers. METHODS: The MGD subjects were recruited and classified as the MGD dry eye subtype based on accepted tests (e.g., Schein symptom survey, tear breakup time, corneal and conjunctival staining, abnormal meibum or meibomian gland atrophy, and a normal Schirmer test). The MGD questionnaire items were drawn from published and anecdotal sources. The preliminary instrument contained 24 items targeting the frequency and intensity of 12 symptoms. Rasch analysis was used for psychometric evaluation of the survey items. RESULTS: Sixty nine MGD subjects completed the survey and clinical testing. Sample severity levels were as follows: none subclinical, 10 minimal, 43 mild, 16 moderate, and none severe. Three iterations of analysis, eliminating INFIT and OUTFIT scores <, and >3.0, and using subject responses reduced the final questionnaire to seven question pairs. Final analysis for the remaining 14 items demonstrated an excellent fit to the Rasch model (e.g., for persons, INFIT MNSQ=0.97; ZSTD=-0.2; OUTFIT MNSQ=0.96; ZSTD=-0.2; item fit statistics were similar). Construct validity also seems good (e.g., correlation to Schein and change with treatment). CONCLUSIONS: The MGD-specific instrument is a valid quantitative measure of the symptoms stemming from MGD sufferers. Further research is necessary to determine whether diagnostic efficacy is sufficient to differentiate the MGD dry eye subtype in an independent sample of normals and both major dry eye subtypes exhibiting a broad severity range.

Quantification of conjunctival TNF-α in aqueous-deficient dry eye.

PURPOSE: This study aimed to quantify and compare conjunctival epithelial tumor necrosis factor (NF) α mRNA expression in Sjögren syndrome (SS), non-Sjögren syndrome aqueous-deficient dry eye (non-SS DE), and non-dry eye (NDE) control subjects. METHODS: A total of 76 subjects were recruited for this study: 25 SS (confirmed via American-European Consensus Criteria 2002), 25 non-SS DE (confirmed by symptoms and Schirmer scores ≤ 10 mm), and 26 NDE. Superior and temporal bulbar conjunctival epithelial cells were collected via impression cytology. Epithelial RNA was extracted, and TNF-α mRNA expression was quantified by real-time quantitative polymerase chain reaction. RESULTS: The expression of TNF-α mRNA was found to be significantly higher in the SS group (2.48 ± 1.79) compared to both non-SS DE (0.95 ± 1.18; p < 0.05) and NDE (0.84 ± 0.51; p < 0.05) groups. No difference in TNF-α mRNA expression was found between the non-SS DE and NDE groups (p = 0.67). CONCLUSIONS: These results demonstrate that SS-associated aqueous-deficient dry eye is associated with a significant upregulation of conjunctival epithelial TNF-α mRNA relative to both non-SS DE and control groups. The degree to which TNF-α mRNA is upregulated in SS may contribute to the severe ocular surface damage observed in these patients.

Biophysical and morphological evaluation of human normal and dry eye meibum using hot stage polarized light microscopy.

PURPOSE: To study melting characteristics and the morphology of human and mouse meibum. METHODS: Hot stage cross-polarized light microscopy (HSPM) and immunohistochemical approaches were used. RESULTS: Isolated human meibum, and meibum of mice (either isolated or within the meibomian ducts of mice), were found to be in liquid-crystal state at physiological temperatures. Melting of both types of meibum started at approximately 10°C and was completed at approximately 40°C. Melting curves of isolated meibum and meibum inside the meibomian ducts were multiphasic with at least two or three clearly defined phase transition temperatures, typically at approximately 12 ± 2°C (minor transition), 21 ± 3°C, and 32 ± 3°C, regardless the source of meibum. Melting was highly cooperative in nature. Samples of abnormal human meibum collected from dry eye patients with meibomian gland dysfunction often showed an increased presence of nonlipid, nonmelting, nonbirefringent, chloroform-insoluble inclusions of a protein nature. The inclusions were positively stained for cytokeratins. The presence of these inclusions was semiquantitatively characterized using a newly proposed 0 to 4 scale. In the presence of large amounts of these inclusions, melting characteristics of meibum and its structural integrity were altered. CONCLUSIONS: HSPM is an effective tool that is suitable for biophysical and morphological evaluation of meibum. Morphological properties and melting characteristics of human meibum were found to be similar to those of mice. Abnormal meibum of many dry eye patients contained large quantities of nonlipid, protein-like inclusions, which were routinely absent in meibum of normal controls.

Quantification of MUCIN 1, cell surface associated and MUCIN16, cell surface associated proteins in tears and conjunctival epithelial cells collected from postmenopausal women.

PURPOSE: To quantify the expression of mucin 1, cell surface associated (MUC1) and mucin 16, cell surface associated (MUC16) proteins and messenger ribonucleic acid (mRNA) in a cohort of postmenopausal women (PMW), to explore the relationship between mucin expression, dry eye symptomology, and tear stability. METHODS: Thirty-nine healthy PMW (>50 years of age) were enrolled in this study. No specific inclusion criteria were used to define dry eye; instead, a range of subjects were recruited based on responses to the Allergan Ocular Surface Disease Index (OSDI) questionnaire and tear stability measurements as assessed by non-invasive tear breakup time (NITBUT). Tears were collected from the inferior tear meniscus using a disposable glass capillary tube, and total RNA and total protein were isolated from conjunctival epithelial cells collected via impression cytology. Expression of membrane-bound and soluble MUC1 and MUC16 were quantified with western blotting, and expression of MUC1 and MUC16 mRNA was assessed with real-time PCR. RESULTS: OSDI responses ranged from 0 to 60, and NITBUT ranged from 18.5 to 2.9 s. Only two statistically significant correlations were found: soluble MUC16 protein concentration and MUC16 mRNA expression with OSDI vision related (-0.47; p=0.01) and ocular symptom (0.39; p=0.02) subscores, respectively. Post hoc exploratory analysis on absolute expression values was performed on two subsets of subjects defined as asymptomatic (OSDI≤6, n=12) and moderate to severe symptomatic (OSDI≥20, n=12). The only significant difference between the two subgroups was a significant reduction in MUC16 mRNA expression found in the symptomatic dry eye group (1.52±1.19 versus 0.57±0.44; p=0.03). CONCLUSIONS: A broad exploration of mucin expression compared to either a sign (NITBUT) or symptoms of dry eye failed to reveal compelling evidence supporting a significant relationship, other than a potential association between MUC16 with specific symptoms. Furthermore, comparison of mucin protein and expression levels between the asymptomatic and moderate to severe symptomatic subgroups revealed only one significant difference, a reduction in MUC16 mRNA expression in the symptomatic subgroup.

Impact of time between collection and collection method on human tear fluid osmolarity.

AIM: To generate data on the variability of tear osmolarity in a control (normal, non-dry eye) and symptomatic dry eye population (Ocular Surface Disease Index: OSDI ≥20). A secondary outcome is the determination of the effect that tear collection technique has on the osmolarity of the sample. MATERIALS AND METHODS: This was a two-phase study that recruited 20 subjects (n = 10 normal, n = 10 dry eye) to evaluate the influence of time between measurements (Phase I) and 30 subjects (n = 15 normal, n = 15 dry eye) to evaluate the influence of collection technique (Phase II). As part of Phase I, serial tear osmolarity measurements were performed on each eye; four separated by 15 min followed by four separated by 1 min, at each of three visits. Phase II compared the consecutive measurement of four in vivo tear samples to four in vitro measurements on tears collected and dispensed from a glass capillary tube. RESULTS: During Phase I, the dry eye group had a significantly higher maximum osmolarity (334.2 ± 25.6 mOsm/L) compared to the normal group (304.0 ± 8.4 mOsm/L, p = 0.002). No significant differences were observed whether collections were performed at 15 or 1 min intervals. During Phase II, the in vivo osmolarity was equivalent to in vitro measurements from glass capillary tube samples for both the dry eye group (323.0 ± 16.7 mOsm/L versus 317.7 ± 24.8, p = 0.496), and for the normal subjects (301.2 ± 7.2 mOsm/L versus 301.9 ± 16.0 mOsm/L, p = 0.884). CONCLUSION: Symptomatic dry eye subjects exhibited a significantly higher tear osmolarity and variation over time than observed in normal subjects, reflecting the inherent tear film instability of dry eye disease. There was no change in the distribution of tear osmolarity measurements whether tears were collected in rapid succession or given time to equilibrate, and collection method had no impact on tear osmolarity.

Molecular structure of interfacial human meibum films.

Meibum is the primary component of the tear film lipid layer. Thought to play a role in tear film stabilization, understanding the physical properties of meibum and how they change with disease will be valuable in identifying dry eye treatment targets. Grazing incidence X-ray diffraction and X-ray reflectivity were applied to meibum films at an air-water interface to identify molecular organization. At room temperature, interfacial meibum films formed two coexisting scattering phases with rectangular lattices and next-nearest neighbor tilts, similar to the Ov phase previously identified in fatty acids. The intensity of the diffraction peaks increased with compression, although the lattice spacing and molecular tilt angle remained constant. Reflectivity measurements at surface pressures of 18 mN/m and above revealed multilayers with d-spacings of 50 Å, suggesting that vertical organization rather than lateral was predominantly affected by meibum-film compression.

Characterization of the interaction between hydroxypropyl guar galactomannan and galectin-3.

Multivalent galactose ligands have been proposed for selective targeting of carbohydrate-binding proteins on epithelial cell surfaces, both in normal and pathological conditions. One cellular partner is galectin-3, a ß-galactoside-binding protein present on many epithelial linings, such as those of the ocular surface. In this study, we investigated the ability of hydroxypropyl guar galactomannan (HPGG) to bind recombinant galectin-3 and to target the apical surface of differentiated human corneal keratinocytes. Pull-down and slot-blot assays demonstrated that fluorescence-labeled HPGG bound recombinant galectin-3 through a galactose-dependent mechanism. In contrast, no binding of HPGG could be detected towards recombinant galectin-8 or -9. In a cell culture system, HPGG bound weakly to biotinylated cell surface corneal isolates containing endogenous galectin-3, and incubation of HPGG with corneal keratinocytes in culture resulted in discrete, galactose-independent, binding to the cell surface. Moreover, HPGG failed to elute the biological counter-receptor MUC16 from galectin-3 affinity columns. We conclude that HPGG binds galectin-3 through the conventional carbohydrate-recognition domain in vitro, but not in a biological system, suggesting that endogenous carbohydrate ligands on epithelial cell surface glycocalyces impair HPGG biorecognition.

Temperature-induced transitions in the structure and interfacial rheology of human meibum.

Meibomian lipids are the primary component of the lipid layer of the tear film. Composed primarily of a mixture of lipids, meibum exhibits a range of melt temperatures. Compositional changes that occur with disease may alter the temperature at which meibum melts. Here we explore how the mechanical properties and structure of meibum from healthy subjects depend on temperature. Interfacial films of meibum were highly viscoelastic at 17°C, but as the films were heated to 30°C the surface moduli decreased by more than two orders of magnitude. Brewster angle microscopy revealed the presence of micron-scale inhomogeneities in meibum films at higher temperatures. Crystalline structure was probed by small angle x-ray scattering of bulk meibum, which showed evidence of a majority crystalline structure in all samples with lamellar spacing of 49 Å that melted at 34°C. A minority structure was observed in some samples with d-spacing at 110 Å that persisted up to 40°C. The melting of crystalline phases accompanied by a reduction in interfacial viscosity and elasticity has implications in meibum behavior in the tear film. If the melt temperature of meibum was altered significantly from disease-induced compositional changes, the resultant change in viscosity could alter secretion of lipids from meibomian glands, or tear-film stabilization properties of the lipid layer.