Cytokines, matrix metalloproteases, angiogenic and growth factors in tears of normal subjects and vernal keratoconjunctivitis patients

Diagnostic criteria of chronic conjunctivitis: atopic keratoconjunctivitis and vernal keratoconjunctivitis

PURPOSE OF REVIEW

Chronic ocular allergies, vernal (VKC) and atopic keratoconjunctivitis (AKC) are relatively rare conditions that require definite diagnostic criteria to the most appropriate therapeutical approach.

RECENT FINDINGS

The diagnosis of both VKC and AKC is generally based on clinical history, signs and symptoms, and the results of allergic tests, which allow to identify the different diseases phenotypes. However, other subtypes of the two diseases and/or overlaps may occur making the diagnosis non always so clear, such as VKC and AKC overlaps or adult-like VKC disease. Each of these phenotypes may be sustained by different mechanisms which are still not well defined but not only related to a type 2 inflammation. The further challenges will be to correlate clinical or molecular biomarkers to a single subtype or disease severity.

SUMMARY

Definite criteria of chronic allergies will further guide to more specific therapeutical approaches.

Novel Insights in the Management of Vernal Keratoconjunctivitis (VKC): European Expert Consensus Using a Modified Nominal Group Technique

INTRODUCTION

Vernal keratoconjunctivitis (VKC) is a rare, severe allergic ocular disease, typically occurring in children and adolescents, that can have a significant impact on quality of life and lead to visual impairment. Long-term treatment may be necessary to tackle chronic inflammation and topical corticosteroid dependency must be minimised due to the risk of complications. There is a need for unified clinical guidance to aid the assessment, diagnosis and management of VKC across Europe. The aim of this expert panel (the EUR-VKC Group) was to provide clear guidance for primary care physicians and general ophthalmologists involved in the diagnosis and management of VKC.

METHODS

An expert group of seven European ophthalmologists was convened and a modified nominal group technique used to develop key recommendations on VKC management. The recommendations were subject to up to two rounds of voting using a 5-point Likert scale to ascertain consensus and the strength of each recommendation. Consensus was set at a predetermined threshold of ≥ 75.0% of experts selecting 'Strongly agree' or 'Agree'.

RESULTS

A total of 47 recommendations were developed relating to the assessment of key of VKC, guidance on who and when to refer, as well as treatment-escalation pathways, long-term follow-up, and supportive care and education. All recommendations reached consensus after two rounds. The group emphasise how timely diagnosis and treatment initiation that is appropriate to disease severity are crucial to benefit patients with VKC. Patients with signs ('red flags') indicating severe VKC, or persistent mild-to-moderate VKC that is non-responsive following 2-4 weeks of treatment, should be referred to a sub-specialist.

CONCLUSION

The EUR-VKC Group provides recommendations on the assessment, diagnosis, management, referral and follow-up of patients with VKC. It also provides a framework to facilitate collaboration between primary care physicians, general ophthalmologists and sub-specialists to improve the outcomes for patients with VKC.

Tissue remodeling in adult vernal keratoconjunctivitis

Our aim is to describe local tissue remodeling in a cohort of adult VKC patients. Male patients diagnosed with active VKC were enrolled in an open pilot study into two groups according disease onset: childhood classic VKC and adult VKC. Visual acuity and ocular surface clinical examination focusing on chronic inflammatory sequelae and impression cytology were performed in all enrolled subjects. Conjunctival imprints were processed for molecular, biochemical and immunofluorescent analysis for tissue remodeling (TGFβ1,2,3 and αSMA) and epigenetic (DNMT3a, Keap1; Nrf2) markers as well as androgen receptors were investigated and compared between groups. Clinical assessment showed increased conjunctival scarring in adult VKC compared to classic VKC. Immunoreactivity for αSMA and expression of TGFβ were higher in adult VKC group. Significantly higher levels of TGFβ3 (3.44 ± 1.66; p < 0.05) were detected in adult VKC compared to childhood VKC, associated with an increasing trend of TGFβ1 (1.58 ± 0.25) and TGFβ2 (1.65 ± 0.20) isoforms levels. Molecular analysis showed a relative increase in tissue remodeling/fibrogenic transcripts (TGFβ isoforms and αSMA) associated to a significant increase of selective epigenetic targets (DNMT3, Nrf2 and keap1) in adult VKC phenotype. Increased local conjunctival androgen receptors was detected in patients with adult variants compared to classic childhood VKC and healthy subjects. Finally, a direct correlation between TGFβ and androgen receptor expression was also detected. A pro-fibrotic clinical and biomolecular trait was unveiled in adult variant of VKC, which causes ocular surface disease and visual impairment.

Evidence of air pollution-related ocular signs and altered inflammatory cytokine profile of the ocular surface in Beijing

We evaluated how different degrees of air pollution affect the ocular surface of a cohort of human subjects in Beijing by correlating in-patient test outcomes with tear cytokines. A cross-sectional study involving 221 volunteers was carried out in different districts of Beijing. Air pollution indices were recorded for 7 d (including the visit day). The indices recorded were the air quality index (AQI), which is a dimensionless measure that quantitatively describes the state of air quality, concentrations of particulate matter smaller than 2.5 μm (PM2.5) and 10 μm (PM10), sulfur dioxide (SO₂), ozone (O₃), and nitrogen dioxide (NO₂). The Ocular Symptom Disease Index (OSDI) questionnaire provided. Subsequently, subjects underwent slit-lamp examination, which included meibomian gland examination, conjunctival congestion score, conjunctivochalasis grade, tear meniscus height (TMH), tear breakup time (TBUT), corneal fluorescein staining (CFS), Schirmer I test, and conjunctival impression cytology. The concentrations of vascular endothelial growth factor (VEGF), interleukins (IL)-1β, IL-6 and IL-8 in tears were measured by microsphere-based immunoassay analysis. According to the value of the AQI, participants are divided into a slightly polluted (SP) group (n = 103) which the AQI value is less than or equal to 100 and a heavily polluted (HP) group (n = 118) whose AQI value is more than 100. Air pollution is related to ocular discomfort based on tear cytokine concentrations. PM2.5, PM10 and NO₂ were positively correlated with OSDI, MG expressibility, meibum score, meiboscore, conjunctival congestion score, Schirmer I test value, TMH, goblet-cell density, concentrations of IL-6, and VEGF were negatively correlated with TBUT. PM2.5 and PM10 appear to be the major risk factors to the ocular surface, with NO₂ being another important risk factor based on this study. The symptoms and signs of eye discomfort in the SP group were significantly less severe than those in the HP group, and tear cytokine concentrations (IL-6 and VEGF) were lower. Air pollution degrees were significantly correlated with tear cytokine concentrations, indicating an alteration of cytokine balance at the ocular surface under different degrees of air pollution.

Tear and ocular surface disease biomarkers: A diagnostic and clinical perspective for ocular allergies and dry eye disease

Validated biomarkers to be used as biological tools for managing ocular surface diseases (OSDs) are still an unmet need in daily clinical practice. Many studies have contributed to the already extensive list of candidate biomarkers for these disorders. Dry eye (DE) and ocular allergy (OA) are complex and multifactorial diseases, often coexisting and with overlapping symptoms. The purpose of this review is to present a comprehensive updated revision of the most relevant biomarkers of DE and OA, with an emphasis on quantitative analyses and correlations with clinical parameter data. Analysis of biomarkers common for these pathologies has highlighted an important physiological process. Namely, the interleukin proteins (IL-1α, IL-1β and IL-17), tumour necrotic factor (TNFα) and interferon gamma (IFNγ; Th1-Th7 pathway) and IL-4, IL-5 and IL-13 (Th2 pathway) seem to represent similar inflammatory mechanisms. Moreover, changes in the levels of mucins (MUC1, MUC2, MUC4, MUC5 and MUC16) are common alterations in the tear film mucous layer. We also examine the current state of medical devices and the main limitations to their use in clinical practice. Translational research in biomarkers for clinical practice depends on a feasible transition from the laboratory to the point-of-care. This requires large-scale, coordinated clinical validation campaigns to select the biomarkers with the highest specificity and sensitivity and significant correlation with clinical parameters. Moreover, technical limitations of multiplexed quantitation systems must be overcome to detect and measure the levels of several biomarkers in very small samples. To ensure the future of biomarker research, significant progress is necessary in a number of fields. There is an urgent need for global unification of clinical classification and diagnostics criteria. Widespread integration of proteomic and transcriptomic data is paramount for performing meaningful analyses using appropriate bioinformatics tools and artificial intelligence systems.

Epithelial barrier dysfunction in ocular allergy

The epithelial barrier is the first line of defense that forms a protective barrier against pathogens, pollutants, and allergens. Epithelial barrier dysfunction has been recently implicated in the development of allergic diseases such as asthma, atopic dermatitis, food allergy, and rhinitis. However, there is limited knowledge on epithelial barrier dysfunction in ocular allergy (OA). Since the ocular surface is directly exposed to the environment, it is important to understand the role of ocular epithelia and their dysfunction in OA. Impaired epithelial barrier enhances allergen uptake, which lead to activation of immune responses and development of chronic inflammation as seen in allergies. Abnormal expression of tight junction proteins that helps to maintain epithelial integrity has been reported in OA but sufficient data not available in chronic atopic (AKC) and vernal keratoconjunctivitis (VKC), the pathophysiology of which is not just complex, but also the current treatments are not completely effective. This review provides an overview of studies, which indicates the role of barrier dysfunction in OA, and highlights how ocular barrier dysfunction possibly contributes to the disease pathogenesis. The review also explores the potential of ocular epithelial barrier repair strategies as preventive and therapeutic approach.

Changes in Anterior and Posterior Corneal Elevation in Patients With Allergic Conjunctivitis

Purpose: To evaluate corneal elevation changes in patients with allergic conjunctivitis (AC) and to analyze their correlations with ocular allergy signs and corneal biomechanical alterations. Methods: Thirty patients (30 eyes) with AC and twenty normal subjects (20 eyes) were included in this prospective study. All participants underwent a complete ocular examination, including corneal tomography by Pentacam and corneal biomechanics evaluation by Corvis ST. AC patients were evaluated for their eye rubbing frequency and ocular allergic signs. Results: The elevation at the thinnest location (TE) and the central location (CE), the elevation difference at the thinnest location (TED) and the central location (CED), and the mean value of elevation difference in the central 4 mm zoom (MED) of both the anterior and posterior corneal surface were significantly higher in the AC group than in the normal group (p < 0.05 for all). In AC patients, only anterior corneal elevation parameters were positively correlated with eye rubbing frequency and ocular allergy sign severity (p < 0.05 for all), while the tomography and biomechanical index (TBI) was positively correlated with the elevation parameters of both the anterior and posterior corneal surfaces (p < 0.05 for all). Conclusion: AC patients carry an increased risk of corneal ectasia. Posterior corneal elevation parameters are sensitive and reliable predictors of keratoconus (KC) risk in AC patients. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04299399, identifier [NCT04299399].

Vernal keratoconjunctivitis activity induces decrease of ocular surface CD14, TLR-4 and TLR-9 expression

PURPOSE

CD14 is involved in the modulation of immune reaction via toll-like receptors (TLR) and may influence the development of allergic diseases. The role of CD14 in vernal keratoconjunctivitis (VKC) has not yet been investigated. The aim of this study is to evaluate changes of tear soluble sCD14 and conjunctival CD14, TLR-4 and 9 expression in patients with VKC in the active and quiescent phases.

METHODS

Eighteen patients with VKC during active inflammation (group A, N = 9), in the quiescent phase (group Q, N = 5) and after recovery (group R, N = 4) and 10 healthy subjects were included. Expression of sCD14 in tears and of CD14, TLR-4, and TLR-9 by conjunctival epithelium were evaluated by Western Blot in all groups.

RESULTS

Expression of tear sCD14 and of conjunctival CD14, TLR-4, and TLR-9 was significantly decreased in group A when compared with healthy subjects and with VKC group Q and R. Lower expression of sCD14, CD14, TLR-4, and TLR-9 were significantly correlated with the severity of papillary reaction, while the lower sCD14 was correlated with severity of conjunctival hyperemia.

CONCLUSIONS

Tear sCD14, and conjunctival CD14, TLR4, and TLR-9 decreased during ocular surface inflammatory reaction in patients with VKC. CD14 and TLRs ocular surface evaluation may represent biomarkers of VKC activity and novel therapeutic target.

Immunopharmacology in Vernal Keratoconjunctivitis: Current and Future Perspectives

Vernal keratoconjunctivitis (VKC) is a complex and chronic, multifactorial Th2 cell-mediated chronic ocular surface inflammatory condition that typically affects predominantly male children in hot or warm climates. The primary symptom is intense ocular pruritus, often significant enough to affect activities of daily living. Clinical features differ from simple forms of allergic conjunctivitis in that they are more-or-less confined to the superior tarsus and limbus. There is also a risk of corneal involvement, which leads to irreversible vision loss in approximately 6% of patients. Right now, there is no standardized treatment protocol, and many of the currently available options are not effective in severe and recurrent cases. As such, it is imperative to understand this complex allergic immune response in order to identify future therapeutic targets. This review will focus on potential drug targets in VKC, with particular emphasis on immunomodulators and immunobiologic agents.

Long-Term Safety and Efficacy of Tacrolimus 0.1% in Severe Pediatric Vernal Keratoconjunctivitis

PURPOSE

The aim of this study was to evaluate the safety and efficacy of tacrolimus 0.1% eye drops in a large population of pediatric patients affected by a severe form of vernal keratoconjunctivitis (VKC) who responded poorly to cyclosporine eye drops.

METHODS

This is a retrospective study based on standardized clinical charts and data collection of consecutive patients affected by severe VKC who responded poorly to cyclosporine eye drops topical treatment but treated with tacrolimus 0.1% eye drops with a follow-up of 18 months. Four clinical signs were graded for analysis: hyperemia, tarsal papillae, giant papillae, and limbal papillae. The blood tests for kidney and liver function and the tacrolimus level were studied. Visits were scheduled at baseline and at 3, 6, 12, and 18 months. Patients received tacrolimus 0.1% eye drops in both eyes 2 times daily.

RESULTS

Four hundred thirty-one patients were included. Three hundred twenty-five patients were affected by a seasonal form, whereas the remaining 106 by a perennial form. Statistical analysis on each single score showed a positive relevance (P < 0.001) from baseline to all other visits. No local or systemic complications were recorded.

CONCLUSIONS

Tacrolimus has been proposed as a treatment for severe forms of VKC. This study has confirmed the safety and efficacy of tacrolimus 0.1% eye drops in a large pediatric population of patients affected by a severe form of VKC who responded poorly to cyclosporine eye drops.

Corneal biomechanical changes in allergic conjunctivitis

Background

To explore corneal biomechanical changes, identify related factors and determine early indicators of keratoconus (KC) development risk in allergic conjunctivitis (AC) patients.

Methods

A total of 50 patients, including 20 eyes without AC and 30 eyes with AC were enrolled in this study. All patients underwent a complete ocular examination, including evaluations of clinical manifestations of AC, corneal tomography and densitometry by Pentacam, corneal biomechanics by Corvis ST, and corneal and epithelial thickness mapping by RTvue optical coherence tomography (OCT).

Results

The index of surface variance (ISV), index of vertical asymmetry (IVA), keratoconus index (KI), index of height decentration (IHD) and Belin/Ambrosio enhanced ectasia total deviation index (BAD-D) were significantly higher in the AC group than in the non-allergic conjunctivitis (NAC) group (P < 0.05). The tomography and biomechanical index (TBI) was also significantly higher in the AC group (P = 0.04). The average epithelial thickness in the 2–7 mm annulus was significantly thinner in the AC group than in the NAC group (P < 0.05). The average densitometry of the total cornea and the anterior layer were higher in the AC group than in the NAC group (P < 0.001). The ISV, IVA, KI, IHD and BAD-D were significantly correlated with the TBI and changes in corneal epithelial thickness in AC patients (P < 0.05). The changes in epithelial thickness were closely related to the eye rubbing frequency and allergic sign scores (P < 0.05).

Conclusions

AC patients should be advised to routinely undergo corneal tomographic and biomechanical measurements, and the TBI could be used as an indicator of KC development risk in AC patients.

Trial registration

Corneal Biomechanical Changes of Allergic Conjunctivitis, NCT04299399. Registered March 3, 2020 - Retrospectively registered.

Tear Proteases and Protease Inhibitors: Potential Biomarkers and Disease Drivers in Ocular Surface Disease

Tears are highly concentrated in proteins relative to other biofluids, and a notable fraction of tear proteins are proteases and protease inhibitors. These components are present in a delicate equilibrium that maintains ocular surface homeostasis in response to physiological and temporal cues. Dysregulation of the activity of protease and protease inhibitors in tears occurs in ocular surface diseases including dry eye and infection, and ocular surface conditions including wound healing after refractive surgery and contact lens (CL) wear. Measurement of these changes can provide general information regarding ocular surface health and, increasingly, has the potential to give specific clues regarding disease diagnosis and guidance for treatment. Here, we review three major categories of tear proteases (matrix metalloproteinases, cathepsins, and plasminogen activators [PAs]) and their endogenous inhibitors (tissue inhibitors of metalloproteinases, cystatins, and PA inhibitors), and the changes in these factors associated with dry eye, infection and allergy, refractive surgery, and CLs. We highlight suggestions for development of these and other protease/protease inhibitor biomarkers in this promising field.

Potential Biomarkers for Allergic Conjunctival Diseases

Allergic conjunctival diseases (ACDs) are a group of ocular allergies that include allergic conjunctivitis, atopic keratoconjunctivitis, vernal keratoconjunctivitis, and giant papillary conjunctivitis. Although a large body of information exists on the pathophysiology of ACDs, this has not yet lead to the development of clear recommendations and guidelines for the diagnosis of ACDs or development of conclusive and objective diagnostic tools. Identification of objectively measurable biomarkers that represent the molecular and cellular mechanisms associated with ACDs will be an important step toward achieving these aims. This is a comprehensive review of biological markers that have the potential to become "biomarker(s)" for ACDs and aid in the classification, diagnosis, and development of new therapeutic strategies for these group of allergic conditions.

Changes in Anterior and Posterior Corneal Elevation in Patients With Allergic Conjunctivitis

Purpose: To evaluate corneal elevation changes in patients with allergic conjunctivitis (AC) and to analyze their correlations with ocular allergy signs and corneal biomechanical alterations. Methods: Thirty patients (30 eyes) with AC and twenty normal subjects (20 eyes) were included in this prospective study. All participants underwent a complete ocular examination, including corneal tomography by Pentacam and corneal biomechanics evaluation by Corvis ST. AC patients were evaluated for their eye rubbing frequency and ocular allergic signs. Results: The elevation at the thinnest location (TE) and the central location (CE), the elevation difference at the thinnest location (TED) and the central location (CED), and the mean value of elevation difference in the central 4 mm zoom (MED) of both the anterior and posterior corneal surface were significantly higher in the AC group than in the normal group (p < 0.05 for all). In AC patients, only anterior corneal elevation parameters were positively correlated with eye rubbing frequency and ocular allergy sign severity (p < 0.05 for all), while the tomography and biomechanical index (TBI) was positively correlated with the elevation parameters of both the anterior and posterior corneal surfaces (p < 0.05 for all). Conclusion: AC patients carry an increased risk of corneal ectasia. Posterior corneal elevation parameters are sensitive and reliable predictors of keratoconus (KC) risk in AC patients. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04299399, identifier [NCT04299399].

The cornea in keratoconjunctivitis sicca

The lacrimal functional unit (LFU) regulates tear production, composition, distribution and clearance to maintain a stable protective tear layer that is essential for maintaining corneal epithelial health. Dysfunction of the LFU, commonly referred to as dry eye, leads to increased tear osmolarity and levels of inflammatory mediators in tears that cause ocular surface epithelial disease, termed keratoconjunctivitis sicca (KCS). Corneal changes in KCS include glycocalyx loss, barrier disruption, surface irregularity inflammatory cytokine/chemokine production, cornification and apoptosis. These can reduce visual function and the increased shear force on the corneal epithelium can stimulate nociceptors sensitized by inflammation causing irritation and pain that may precede frank clinical signs. Therapy of keratoconjunctivitis sicca should be tailored to improve tear stability, normalize tear composition, improve barrier function and minimize shear forces and damaging inflammation to improve corneal epithelial health.

Chemokines in allergic conjunctivitis

PURPOSE OF REVIEW

Chemokines are a large group of low molecular weight cytokines that attract and activate leukocytes throughout the body and therefore have a key role in the framework of late-phase allergic responses. The purpose of this article is to provide an overview of the main chemokines involved in allergic conjunctivitis, their primary functions and their physiological roles, and therapies targeted at chemokines and their receptors for ocular allergic diseases.

RECENT FINDINGS

In recent years, there have been considerable advances in the understanding of ocular pathophysiology of ocular surface inflammatory diseases including both allergic eye diseases and dry eye syndrome. Several therapies being developed for dry eye inflammation are recognized as possible therapies for ocular allergic diseases as there are often common chemokines involved in both disease spectra.

SUMMARY

Chemokines represent an integral part of the late-phase cascade of ocular allergic inflammation. A deep understanding of specific chemokines and their interactions will help in targeting therapies to effectively manage ocular clinical findings and symptoms of allergic eye disease.

Omalizumab in three children with severe vernal keratoconjunctivitis

Background

Vernal keratoconjunctivitis (VKC) is a rare, recurrent form of ocular allergy that can be refractory to topical and systemic treatment. It typically presents as acute and chronic keratoconjunctival inflammation that may lead to visual impairment due to corneal ulcers and scaring. Patients often suffer from atopic IgE-driven comorbidities, especially atopic eczema. Children are frequently affected and often do not tolerate topical treatment well, especially if photophobia and pain impair therapy adherence. We present three children with severe VKC who were not controlled by first- and second-line topical and systemic therapy and finally responded to treatment with the monoclonal anti-IgE antibody omalizumab as third-line treatment.

Methods and results

We retrospectively analyzed three patients with VKC having failed response to first- and second-line treatment. All three boys had very early allergic rhinoconjunctivitis from age 1–3 with polysensitization: birch, grass pollen, house dust mite, and/or pets. All received subcutaneous or sublingual immunotherapy (SCIT/SLIT) for birch and/or grass pollen without major success. Two patients had comorbidities: allergic asthma and severe atopic dermatitis (AD). For at least 6 months after the first administration, monoclonal anti-IgE antibody omalizumab (150 or 300 mg) was administered subcutaneously every 2–6 weeks in all patients achieving improvement of the clinical grading scale from VKC grade 3–4 to grade 1–2. One patient had a relapse mainly of his AD and achieved complete control of AD and VKC by introduction of dupilumab.

Conclusion

Although the clinical benefit of omalizumab in asthma and chronic spontaneous urticaria (CSU) has been established in several clinical trials, there are very little data about its effect on severe VKC. In addition to few previously reported cases we can report the rapid effectiveness of omalizumab in VKC clinically and in terms of quality of life. Randomized trials are needed to include omalizumab in third-line treatment of VKC for prevention of visual impairment and further sequelae such as corneal damage.

Scleral lens wear: Measuring inflammation in the fluid reservoir

PURPOSE

To measure inflammatory mediators in the scleral lens fluid reservoir (FR) in healthy eyes and to compare them to basal tear samples after 8-hs (8h) and 4-days (4d) of scleral lens (SL) wear.

METHODS

Fifteen normal, habitual soft contact lens wearers were fitted with 14.8- or 15.4-mm SLs (Zenlens, Alden Optical, USA). Basal ocular surface tears and FR samples were collected after 8h and 4d of daily SL wear. Levels of interleukin (IL) -4 and -8, matrix metalloproteinase (MMP)-7, -9, and -10, and tissue inhibitor of MMPs (TIMPs) 1-4 were measured in all samples using Luminex assays. Visual acuity, corneal and conjunctival staining, and comfort assessments were completed at the baseline, 8h and 4d time points.

RESULTS

MMP-9 and MMP-10 were greater in FR than basal ocular surface tears. After 8h of SL wear, the median concentration of MMP-9 in the FR and basal tears were 62.7 and 15.2 ng/mL, respectively (p = 0.047). Likewise, MMP-10 was significantly greater in FR compared to basal tears, after 8h (25.8 ng/mL vs 2.8 ng/mL, p < 0.001) and 4d (2.1 ng/mL vs17.2 ng/mL, p = 0.047). IL-4 and IL-8 levels were greater in FR but not significantly at 8h (2.2 vs 3.1 ng/mL; and 0.1 vs 0.4 ng/mL, respectively) or 4d (0.9 vs 3.5 ng/mL; 0.0 vs 0.2 ng/mL). MMP-7 was not affected by SL wear after 8h (46.0 basal vs 54.4 ng/mL FR) or 4d (34.2 vs 87.5 ng/mL). Visual acuity, corneal and conjunctival staining did not change; comfort was reduced in SL compared to soft contact lens wear.

CONCLUSIONS

This is the first study to compare the FR with the basal ocular surface tears. MMP-9 and MMP-10 were elevated in the FR after several hours of SL wear, suggesting potential clinical implications of SL wear and deserves further investigation.

Effectiveness of Subconjunctival Cyclosporine in Treatment of Acute Allergic Conjunctivitis in a Rat-Model

Background

Eye allergy is widely spread worldwide. The treatment includes topical anti-histamines, steroids and non-steroidal drugs. Steroids are the first choice by many ophthalmologists, but unfortunately they may cause serious side effects. Cyclosporine A (CsA) is an immunomodulator drug that can improve eye allergy and reduce the need for steroids; however, topical preparation of CsA is difficult because of the lipophilic nature of the drug.

Methods

An experimental study included 16 rats with induced allergy were divided into 2 groups. Group 1: allergic non-treated (6 rats), and Group 2: allergic treated with 0.5 mL subconjunctival CsA 1% (10 rats). Half of each group was sacrificed at 24 hrs and the other half at 1 week. Conjunctival hyperemia and eosinophilic cell count were assessed at each time.

Results

Group 2 (CsA treated) showed significantly lower hyperemia score and eosinophilic count at both 24 hrs and 1 week. No ocular complications were noted.

Conclusion

Subconjunctival CsA was safe and effective in treating ocular allergy through improving conjunctival hyperemia and reducing eosinophilic cell count with no significant ocular side effects.

Cytokine tear film profile determination in eyes of healthy dogs and those with inflammatory periocular and skin disorders

Alterations in serum cytokine levels and profiles have been reported in association with a variety of disease conditions (e.g., allergic, immune-mediated, etc.) in both humans and animals. In comparison to serum cytokine measurements, tear cytokine measurements might be expected to more accurately reflect the inflammatory milieu associated with periocular disease. The purpose of this study was to use a multiplexed assay to compare the cytokine profile of tears in healthy dogs to those with inflammatory skin and periocular disease. We were able to detect IL-2, IL-6, IL-8, and TNF-α in >47 % of tear samples from both healthy canine patients and those with inflammatory dermatologic disease (with or without concurrent periocular involvement). In contrast, IL-7, IL-10 and IFN-γ were rarely detected. Dogs with both dermatologic and periocular disease (but not dermatologic disease alone) had higher levels of IL-8 (P < 0.001, P > 0.05, respectively) relative to healthy dogs. Patients with concurrent dermatologic and periocular disease also demonstrated significantly greater variability in IL-8 concentrations between eyes than did healthy dogs (P < 0.0001). Our findings suggest that tear cytokine analysis may prove to be a useful tool to investigate the role and interactions of the local ocular immune response in patients with inflammatory periocular disease.

Meibography and corneal volume optical coherence tomography to quantify damage to ocular structures in children with blepharokeratoconjunctivitis

PURPOSE

To evaluate non-contact infrared meibography and anterior segment optical coherence tomography (AS-OCT) to detect meibomian gland (MG) and corneal changes in children with blepharokeratoconjunctivitis (BKC).

METHODS

We acquired infrared meibography images of upper and lower lids and AS-OCT corneal scans. One masked observer graded meiboscore, full/partial MG dropout, and measured total corneal volume and differential corneal volume per quadrant and central corneal thickness (CCT).

RESULTS

We enrolled 63 children, 31 with BKC and 32 without ocular surface inflammation; median (interquartile range) age BKC 10.6 (7.2-13.9) years, healthy volunteers (HV) 11.4 (9.5-13.8) years. Likert scale scores for meibography and OCT indicate no to low discomfort. Meiboscores for upper and lower lids as well as the total meiboscore were significantly higher in children with BKC than in HV. Subscores for full and partial MG dropout were also significantly higher in children with BKC than in healthy volunteers. There was no statistically significant difference between upper and lower lid for meiboscore nor full/partial MG dropout scores. The corneal volume in the superior quadrant was significantly higher in children with BKC than in HV, whereas the corneal volume in the nasal and inferior quadrants was significantly lower.

CONCLUSIONS

Non-contact imaging technologies objectively demonstrate damage to meibomian glands and changes in corneal volume secondary to BKC. The tests are well tolerated by children with mild/moderate ocular surface inflammation and can detect changes without the requirement for routine eversion of the upper lid. These parameters may be useful both for clinical follow-up and clinical trials.

Histamine-Induced Conjunctivitis and Breakdown of Blood-Tear Barrier in Dogs: A Model for Ocular Pharmacology and Therapeutics

Conjunctival inflammation disturbs the blood–tear barrier and thus affects the tear film stability and composition. We aimed to develop a non-invasive and reliable method to induce conjunctivitis in dogs, a large animal model for translational work on ocular surface disease in humans. Six beagle dogs underwent a randomized, vehicle-controlled, balanced crossover trial—on six separate days, one eye received topical artificial tears (vehicle), while the other eye received one of six concentrations of histamine solution (0.005–500 mg/ml). At sequential times after eyedrop administration, a conjunctivitis score was given to each eye based on the degree of palpebral and bulbar conjunctival hyperemia and chemosis, ocular pruritus, and discharge. Total protein content (TPC) and serum albumin were quantified in tear fluid at baseline and 20 min. Additionally, 13 dogs presenting for various ophthalmic diseases with associated conjunctivitis were examined. Experimentally induced conjunctivitis developed rapidly (<1 min) following topical histamine administration and lasted for 1–3 h (four lowest doses) to 6–8 h (two highest doses). The severity of conjunctivitis was dose-dependent. Histamine was overall well tolerated, although transient blepharitis, aqueous flare, and ocular hypertension occurred in a few dogs receiving histamine ≥375 mg/ml. TPC and serum albumin levels increased in tears of eyes receiving histamine ≥1.0 mg/ml, being significantly higher than vehicle and baseline in eyes receiving histamine ≥375 mg/ml. Lacrimal albumin levels were also increased in 13 dogs with naturally acquired conjunctivitis, up 2.7–14.9 fold compared to contralateral healthy eyes. Histamine-induced conjunctivitis represents a robust model for translational work on the ocular surface given the low cost, non-invasiveness, self-resolving nature, ability to adjust the duration and severity of the disease, and shared features with naturally occurring ocular diseases. Histamine solutions of 1, 10, and 375 mg/ml induce mild, moderate, and severe conjunctivitis in dogs, respectively. Leakage of serum albumin in tear fluid of eyes with conjunctivitis suggests a breakdown of the blood–tear barrier.

Vernal Keratoconjunctivitis: an update focused on clinical grading system

Introduction

Vernal keratoconjunctivitis (VKC) is a severe disease with a prevalence of < 1 case out of 10,000 in Europe, which occurs mainly in pediatric age and is characterized by a severe and often bilateral chronic inflammation of the ocular surface. The diagnosis is generally confirmed by the finding at the ocular examination of conjunctival hyperemia, papillary hypertrophy in the tarsal conjunctiva, giant papillae, papillae in the limbus region.

Objective

Aim of this review is to provide an updated overview on the disease focused on clinical grading system, searching papers published in the last decade on VKC in scientific databases.

Results

Currently there are no standardized criteria for diagnosis of VKC and there is no uniformity to define disease severity, which makes difficult to diagnose and treat the disease.

Conclusions

Given the wide overlap of the symptoms of VKC with the allergic conjunctivitis, criteria of probable, possible or improbable diagnosis are needed, providing pediatricians with parameters useful for deciding whether to drive the patient to the ophthalmologist for diagnostic confirmation.

Tears and ocular surface disorders: Usefulness of biomarkers

INTRODUCTION

Corroborating data suggest that the analysis of tear fluid might represent an additional tool in the ophthalmological practice.

AREAS COVERED

The purpose of this review was to sum up the tear protein profiles in healthy and diseased ocular surface and to highlight biomarker usefulness in the early diagnosis as well as at follow-up. This analysis encompasses a deep examination of the protein profile expression under physiological and pathological conditions. Tear protein profile analysis will allow in the near future discriminating between different grades of inflammation, from acute trauma toward immune-, endocrine-, and nervous-related disorders of the ocular surface.

CONCLUDING REMARKS

The review provides an overview of old and recent findings about inflammatory mediators identified at the ocular surface, under physiological and pathological conditions. To date, the analysis of tear fluid represents a new additional approach for diagnosis and management of ocular surface diseases. Understanding the pathophysiological mechanism could also offer significant advantages to develop strategies addressed to better clarify some complex ocular surface disorders. To sum up, the possibility to provide selective biomarkers as a future target of specific diseases should be considered for supporting diagnosis and management of ocular surface diseases.

Vascular Endothelial Growth Factor (VEGF) Serological and Lacrimal Signaling in Patients Affected by Vernal Keratoconjunctivitis (VKC)

Background

Vernal keratoconjunctivitis (VKC) is a rare inflammatory disease involving the ocular surface, with seasonally exacerbated symptoms. Both type-1 and type-4 hypersensitivity reactions play a role in the development of VKC.

Purpose

The aim of the present study was to assess the presence and evaluate the concentration of the vascular endothelial growth factor (VEGF) in tear and blood samples from patients with VKC, during the acute phase, based on the histopathological vasculostromal structure of the tarsal papillae.

Methods

Two groups of children aged between 6 and 16 years of life were enrolled: 21 patients (16 males, 76%) affected by VKC, tarsal or mixed form, and 13 healthy children (5 males, 38%) used as controls. Blood and tear samples were obtained from all patients, in order to specifically assess the presence of VEGF. Statistical analyses were performed with one-way ANOVA, followed by post hoc comparisons with the Bonferroni tests. Pearson's correlation was chosen as statistical analysis to assess the relationship between the expression levels of VEGF in tears and blood and the clinical parameters measured.

Results

Comparing the 2 groups for VEGF concentration, a statistically significant difference was found in tear samples: the mean value was 12.13 pg/mL (±5.54 SD) in the patient group and 7 pg/ml (±4.76 SD) in controls (p < 0.05). However, no statistically significant difference was found when comparing VEGF concentration in blood samples (p > 0.05), with a mean value of 45.17 pg/mL (±18.67 SD) in VKC patients and 38.08 pg/mL (±19.43 SD) in controls.

Conclusions

This pilot study highlights the importance of lacrimal and vascular inflammatory biomarkers that can be detected in VKC patients during the acute phase, but not in healthy children. The small group of patients warrants additional studies on a larger sample, not only to further investigate the role of VEGF but also to evaluate the angiogenic biomarkers before and after topical treatment.

Current and emerging therapies for corneal neovascularization

The cornea is unique because of its complete avascularity. Corneal neovascularization (CNV) can result from a variety of etiologies including contact lens wear; corneal infections; and ocular surface diseases due to inflammation, chemical injury, and limbal stem cell deficiency. Management is focused primarily on the etiology and pathophysiology causing the CNV and involves medical and surgical options. Because inflammation is a key factor in the pathophysiology of CNV, corticosteroids and other anti-inflammatory medications remain the mainstay of treatment. Anti-VEGF therapies are gaining popularity to prevent CNV in a number of etiologies. Surgical options including vessel occlusion and ocular surface reconstruction are other options depending on etiology and response to medical therapy. Future therapies should provide more effective treatment options for the management of CNV.

Vitamin D levels in children affected by vernal keratoconjunctivitis

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a chronic and often severe bilateral conjunctivitis. VKC etiology still remains unclear although endocrine, genetic, neurogenic and environmental factors have been implicated. Vitamin D is a fat-soluble prohormone whose main function is the regulation of calcium and phosphate metabolism. The aim of this study was to evaluate serum vitamin D in children affected by VKC compared to the healthy children and investigate the relationship between its levels and disease severity.

METHODS

A total of 110 children, 47 affected by VKC, aged between 5 and 12 years were enrolled at the Department of Pediatrics, Division of Allergy and Immunology, "Sapienza" University of Rome. Used as controls were 63 healthy children with negative skin prick test (SPT), without allergic, ocular and systemic disease. Serum samples were obtained in April from all the children included in the study. Vitamin D dosage was repeated in October in 20 patients after therapy and in 20 controls. A conjunctival scraping was performed in all children affected by VKC.

RESULTS

Children affected by VKC had lower vitamin D levels compared to healthy controls and we found an increase in vitamin D levels after therapy with cyclosporine eye drops 1% although this increase was lower than that of healthy controls. Moreover we found significant correlations between vitamin D level and the severity of the disease.

CONCLUSIONS

The study shows that children affected by VKC have lower vitamin D levels when compared to healthy controls and highlights a significant correlation between its levels and disease severity.

Membrane array and multiplex bead analysis of tear cytokines in systemic sclerosis

Although serious ocular manifestations of systemic sclerosis (SSc) have been described, tear analysis of patients with SSc has not been performed in previous studies. Our aim was to measure a wide panel of cytokines and chemokines in tears of patients with SSc and to assess the most significant molecules with a more sensitive and specific method. Unstimulated tear samples were collected from nine patients with SSc and 12 age- and gender-matched healthy controls. The relative levels of 102 different cytokines were determined by a cytokine array, and then absolute levels of four key cytokines were determined by a magnetic bead assay. Array results revealed shifted cytokine profile characterized by predominance of inflammatory mediators. Of the 102 analyzed molecules, nine were significantly increased in tears of patients with SSc. Based on the multiplex bead results, C-reactive protein, interferon-γ-inducible protein-10, and monocyte chemoattractant protein-1 levels were significantly higher in tears of patients with SSc. Our current data depict a group of inflammatory mediators, which play a significant role in ocular pathology of SSc; furthermore, they might function as excellent candidates for future therapeutic targets in SSc patients with ocular manifestations.

Very Low Prevalence of Keratoconus in a Large Series of Vernal Keratoconjunctivitis Patients

PURPOSE

To evaluate the prevalence of keratoconus (KC) and other corneal abnormalities by means of videokeratography and tomography in a large series of patients affected by vernal keratoconjunctivitis (VKC).

DESIGN

Cross-sectional study.

METHODS

Setting: Single-center children's hospital.

STUDY POPULATION

A total of 651 consecutive patients with VKC and a control group of 500 were prospectively recruited between May 1, 2012 and September 30, 2013, with a minimum follow-up of 12 months.

OBSERVATION PROCEDURE

All patients were evaluated by means of a Scheimpflug camera combined with a Placido corneal topographer. Keratoconus, suspected keratoconus, or its absence were determined in each patient. The corneal symmetry index of front (SI_f) and back curvature (SI_b), shape indices, and thicknesses were compared between the 2 groups.

MAIN OUTCOME MEASURES

Prevalence of keratoconus and corneal indices modifications.

RESULTS

Five out of 651 patients (0.77%) demonstrated topographic signs of KC. Two of them were bilateral. All patients were older than 7 years of age, and the mean age was 11.54 years. Four other patients (0.61%) were classified as KC suspects by the screening program. Of 304 patients older than 11 years (mean age 14.4 years), 4 (1.32%) were found to have KCN, and 4 (1.32%) were KC suspects. The corneal indices of patients in the VKC group were extremely similar to those in the control group. (P > .05).

CONCLUSIONS

The prevalence of KC in our patient population, compared with previous reports in the literature, is much lower. The similar corneal indices in both groups suggest the absence of permanent corneal deformation due to VKC.

Quiescent and Active Tear Protein Profiles to Predict Vernal Keratoconjunctivitis Reactivation

Objective. Vernal keratoconjunctivitis (VKC) is a chronic recurrent bilateral inflammation of the conjunctiva associated with atopy. Several inflammatory and tissue remodeling factors contribute to VKC disease. The aim is to provide a chip-based protein analysis in tears from patients suffering from quiescent or active VKC. Methods. This study cohort included 16 consecutive patients with VKC and 10 controls. Participants were subjected to clinical assessment of ocular surface and tear sampling. Total protein quantification, total protein sketch, and protein array (sixty protein candidates) were evaluated. Results. An overall increased Fluorescent Intensity expression was observed in VKC arrays. Particularly, IL1β, IL15, IL21, Eotaxin2, TACE, MIP1α, MIP3α, NCAM1, ICAM2, βNGF, NT4, BDNF, βFGF, SCF, MMP1, and MMP2 were increased in quiescent VKC. Of those candidates, only IL1β, IL15, IL21, βNGF, SCF, MMP2, Eotaxin2, TACE, MIP1α, MIP3α, NCAM1, and ICAM2 were increased in both active and quiescent VKC. Finally, NT4, βFGF, and MMP1 were highly increased in active VKC. Conclusion. A distinct “protein tear-print” characterizes VKC activity, confirming some previously reported factors and highlighting some new candidates common to quiescent and active states. Those candidates expressed in quiescent VKC might be considered as predictive indicators of VKC reactivation and/or exacerbation out-of-season.

Chaperone patterns in vernal keratoconjunctivitis are distinctive of cell and Hsp type and are modified by inflammatory stimuli

BACKGROUND

Vernal keratoconjunctivitis (VKC) is a severe ocular allergy with pathogenic mechanism poorly understood and no efficacious treatment. The aims of the study were to determine quantities and distribution of Hsp chaperones in the conjunctiva of VKC patients and assess their levels in conjunctival epithelial and fibroblast cultures exposed to inflammatory stimuli.

METHODS

Hsp10, Hsp27, Hsp40, Hsp60, Hsp70, Hsp90, Hsp105, and Hsp110 were determined in conjunctiva biopsies from nine patients and nine healthy age-matched normal subjects, using immunomorphology and qPCR. Conjunctival epithelial cells and fibroblasts were cultured and stimulated with IL-1β, histamine, IL-4, TNF-α, or UV-B irradiation, and changes in Hsp levels were determined by Western blotting.

RESULTS

Hsp27, Hsp40, Hsp70, and Hsp90 levels increased in the patients' conjunctiva, whereas Hsp10, Hsp60, Hsp100, and Hsp105 did not. Double immunofluorescence demonstrated colocalization of Hsp27, Hsp40, Hsp70, and Hsp90 with CD68 and tryptase. Testing of cultured conjunctival cells revealed an increase in the levels of Hsp27 in fibroblasts stimulated with IL-4; Hsp40 in epithelial cells stimulated with IL-4 and TNF-α and in fibroblasts stimulated with IL-4, TNF-α, and IL-1β; Hsp70 in epithelial cells stimulated with histamine and IL-4; and Hsp90 in fibroblasts stimulated with IL-1β, TNF-α, and IL-4. UV-B did not induce changes.

CONCLUSIONS

VKC conjunctiva displays distinctive quantitative patterns of Hsps as compared with healthy controls. Cultured conjunctival cells respond to cytokines and inflammatory stimuli with changes in the Hsps quantitative patterns. The data suggest that interaction between the chaperoning and the immune systems drives disease progression.

Component-resolved diagnostics in vernal conjunctivitis

BACKGROUND

Conventional diagnostic tests in allergy are insufficient to clarify the origin of vernal conjunctivitis (VC).

OBJECTIVES

To evaluate IgE-mediated hypersensitivity by component-resolved diagnosis (CRD) in tears and serum from patients with VC and to evaluate how to treat patients with identified triggering allergens by specific immunotherapy.

METHODS

Patients were divided into 3 groups: (1) patients with VC (25 patients), (2) patients allergic to grass pollen with seasonal allergic conjunctivitis (AC) (50 patients), and (3) healthy blood donors (50 patients). If triggering allergens were detected, specific conventional immunotherapy was administered for 1 year.

RESULTS

Twenty-five patients with VC were evaluated. The identified triggering allergens were n Lol p 1 (11 patients), n Cyn d 1 (8 patients), group 4 and 6 grasses (6 patients), and group 5 grasses (5 patients). Prick test and pollen IgE test results were positive in one patient. Clinical improvement was observed in 13 of the 25 patients with VC after 1 year of specific immunotherapy.

CONCLUSION

CRD seems to be a more sensitive diagnostic tool compared with prick test and IgE detection. Specific CRD-led immunotherapy may achieve clinical improvements in patients with VC.

Effects of awakening and the use of topical dexamethasone and levofloxacin on the cytokine levels in tears following corneal transplantation

Objectives. To study the short-term effect of eye opening and use of topical dexamethasone phosphate 0.1% and levofloxacin 0.5% on the cytokine levels in human tears. Methods. Prospective experimental design was used for tear collection from eyes of 10 healthy controls and 20 patients four days after penetrating keratoplasty (PKP) at awakening and after instilling dexamethasone or levofloxacin. The concentrations of different cytokines were measured by cytometric bead array. Results. At eye opening, IL-6 levels were higher in the PKP group as compared to the controls. Thirty minutes later, the released levels of IL-10, IL-13, IL-17, IFNγ, and CCL5 increased in controls, while CXCL8 decreased in both control and PKP groups. The release of the cytokines remained stable after 30 mins except for IFNγ, which showed a decrease in the controls following levofloxacin instillation. No short-term effects of the topically used dexamethasone and levofloxacin could be detected on the cytokine levels in controls and after PKP. Conclusions. Evidence of changes in the levels and time course of tear cytokines after awakening or eye opening could be established and the short-term confounding effects of dexamethasone and levofloxacin on the levels of released cytokines in human tears could be excluded.

Cytokines in tears during the secondary keratoconjunctival responses induced by allergic reaction in the nasal mucosa

BACKGROUND

Allergic keratoconjunctivitis (KC) can occur in a primary form due to an allergic reaction taking place in the conjunctivae or in a secondary form induced by nasal allergy.

OBJECTIVES

To search for the cytokine changes in tears accompanying the secondary keratoconjunctival response types (SKCR), caused by the nasal allergy.

METHODS

In 43 KC patients developing 15 immediate (SIKCR), 16 late (SLKCR) and 12 delayed (SDYKCR) responses to nasal provocation tests with allergens (NPT), the NPTs were repeated with subsequent recording of cytokine concentrations in tears up to 72 h.

RESULTS

The SIKCRs (p<0.001), occurring 10-120 min after the NPT, were accompanied by significant changes (p<0.05) of interleukin (IL)-4, IL-6, IL-10, IL-12p70 and granulocyte-macrophage colony-stimulating factor (GM-CSF). The SLKCRs (p<0.01), appearing 5-12 h after the NPT, were associated with significant changes (p<0.05) of IL-3, IL-4, IL-5, IL-8, IL-10, tumor necrosis factor (TNF)-α, GM-CSF and granulocyte colony-stimulating factor. The SDYKCRs (p<0.01), occurring 24-48 h after the NPT, were accompanied by significant changes (p<0.05) of IL-2, IL-8, IL-10, interferon-γ, transforming growth factor-β and TNF-α.

CONCLUSIONS

The particular SKCR types, induced by an allergic reaction in the nasal mucosa, were accompanied by different cytokine profiles in the tears, suggesting involvement of different hypersensitivity mechanisms. These results also stress the diagnostic usefulness of NPTs combined with monitoring of ocular features in KC patients who did not respond satisfactorily to the topical ophthalmological treatment.

Vernal keratoconjunctivitis: a severe allergic eye disease with remodeling changes

Vernal keratoconjunctivitis (VKC) is an unusually severe sight-threatening allergic eye disease, occurring mainly in children. Conventional therapy for allergic conjunctivitis is generally not adequate for VKC. Pediatricians and allergists are often not familiar with the severe clinical symptoms and signs of VKC. As untreated VKC can lead to permanent visual loss, pediatric allergists should be aware of the management and therapeutic options for this disease to allow patients to enter clinical remission with the least side effects and sequelae. Children with VKC present with severe ocular symptoms, that is, severe eye itching and irritation, constant tearing, red eye, eye discharge, and photophobia. On examination, giant papillae are frequently observed on the upper tarsal conjunctiva (cobblestoning appearance), with some developing gelatinous infiltrations around the limbus surrounding the cornea (Horner-Trantas dot). Conjunctival injections are mostly severe with thick mucus ropy discharge. Eosinophils are the predominant cells found in the tears and eye discharge. Common therapies include topical antihistamines and dual-acting agents, such as lodoxamide and olopatadine. These are infrequently sufficient and topical corticosteroids are often required for the treatment of flare ups. Ocular surface remodeling leads to severe suffering and complications, such as corneal ulcers/scars. Other complications include side effects from chronic topical steroids use, such as increased intraocular pressure, glaucoma, cataract and infections. Alternative therapies for VKC include immunomodulators, such as cyclosporine A and tacrolimus. Surgery is reserved for those with complications and should be handled by ophthalmologists with special expertise. Newer research on the pathogenesis of VKC is reviewed in this article. Vernal keratoconjunctivitis is a very important allergic eye disease in children. Complications and remodeling changes are unique and can lead to blindness. Understanding of pathogenesis of VKC may lead to better therapy for these unfortunate patients.

Tear fluid protein biomarkers

The tear film covers and protects the ocular surface. It contains various molecules including a large variety of proteins. The protein composition of the tear fluid can change with respect to various local and systemic diseases. Prior to the advent of the proteomic era, tear protein analysis was limited to a few analytical techniques, the most common of which was immunoelectrophoresis, an approach dependent on antibody availability. Using proteomics, hundreds of tear proteins could potentially be identified and subsequently studied. Although detection of low-abundance proteins in the complex tear proteome remains a challenge, advances in sample fractionation and mass spectrometry have greatly enhanced our ability to detect these proteins. With increasing proteomic applications, tears show great potential as biomarkers in the development of clinical assays for various human diseases. In this chapter, we discuss the structure and functions of the tear film and methods for its collection. We also summarize potential tear protein biomarkers identified using proteomic techniques for both ocular and systemic diseases. Finally, modern proteomic techniques for tear biomarker research and future challenges are explored.

The influence of benign essential blepharospasm on dry eye disease and ocular inflammation

PURPOSE

To study the influence of blepharospasm on dry eye disease by analyzing the clinical features, tear cytokine, and treatment response of patients with dry eye disease accompanied by benign essential blepharospasm.

DESIGN

Prospective case series study.

METHODS

Forty adults with a diagnosis of benign essential blepharospasm (BEB) and dry eye disease (DED) were consecutively recruited. Forty subjects with dry eye disease only and 40 healthy adults were recruited as eligible controls. A tear specimen was collected from all participants for cytokine analysis. The patients with benign essential blepharospasm were treated with botulinum neurotoxin type A. The main outcome measures were the following: (1) Ocular Surface Disease Index (OSDI) questionnaire; (2) clinical features, including tear break-up time (BUT), Schirmer І test, and fluorescein staining; (3) conjunctival impression cytology; and (4) multiplex cytokine immunobead assay.

RESULTS

The symptoms of DED + BEB patients were significantly different from those of DED controls and healthy controls. Cytokine analysis in tear fluid also showed that tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-2, IL-17, and vascular endothelial growth factor levels were significantly increased in DED + BEB patients. In treatment, botulinum neurotoxin type A injection effectively relieved blepharospasm in all of the DED + BEB patients. Moreover, in this group of patients, OSDI decreased significantly after the botulinum neurotoxin type A injection, and BUT was increased as well.

CONCLUSION

BEB may participate in the progress of inflammation in DED + BEB patients. Botulinum neurotoxin type A injections could effectively relieve the symptoms of DED + BEB patients and improve their ocular surface condition.

Identification of human tear fluid biomarkers in vernal keratoconjunctivitis using iTRAQ quantitative proteomics

BACKGROUND

Understanding and treating vernal keratoconjunctivitis (VKC) has been a challenge because the pathogenesis is unclear and antiallergic therapy often unsuccessful. The aim of the study was to analyze peptide profiles in human tears using mass spectrometry to elucidate compositional differences between healthy subjects and patients affected by VKC.

METHODS

Tears were collected from healthy subjects and VKC patients. Digested samples were treated with iTRAQ (isobaric tag for relative and absolute quantitation). Separation of tryptic peptides was realized using a MicroHPLC interfaced with a microfraction collector. MS and MS/MS mass spectra were performed using a MALDI TOF/TOF 4800 Applied Biosystem spectrometer. Protein Pilot™ software with Paragon™ algorithm v4.1.46 or GPS™ with Mascot engine was used as search engines with SwissProt or IPI human as the databases.

RESULTS

A significant number of peptides were examined, and 78 proteins were successfully identified. In all VKC samples, levels of serum albumin, transferrin, and hemopexin were found up to 100 times higher than control tear levels and correlated to the severity of disease. Hemopexin, transferrin, mammaglobin B, and secretoglobin 1D were found significantly over-expressed in VKC samples compared with the control samples. Tear samples from patients treated with topical cyclosporine or corticosteroids showed a dramatic reduction in these protein levels.

CONCLUSIONS

LC MALDI MS and isobaric tag for relative and absolute quantitation technique may be useful in the quantitative and qualitative characterization of the peptidoma of human tears. These techniques may identify target proteins to be used in the diagnosis and management of VKC and other inflammatory ocular surface conditions.

Effect of vernal keratoconjunctivitis on vitreous depth in patients with keratoconus

PURPOSE

The aim of this study was to comparatively evaluate the vitreous depth (VD) of keratoconic eyes in patients with or without vernal keratoconjunctivitis (VKC).

MATERIAL AND METHODS

Eighty eyes of 80 consecutive keratoconus (KC) patients and 40 emmetropic control subjects were enrolled. KC patients were divided into two groups according to accompanying VKC (VKC-KC group and KC group). Mean outcome measures were best-corrected visual acuity (BCVA), spherical equivalent (SE), mean keratometry (Km), intraocular pressure (IOP), and axial length (AL) and its components. The eyes with the highest Km were selected for statistical analysis for each participant.

RESULTS

There were 50, 30, and 40 patients in the VKC-KC group, KC group, and control group respectively. The KC group and VKC-KC group were similar in BCVA, SE, Km, CCT, ACD, LT, and IOP (p>0.05). The mean ACD was significantly lower in the control group when compared with the KC group and VKC-KC group. The mean AL and VD were significantly higher in VKC-KC group than those of KC group and the control group, whereas similar in KC and control groups (p>0.05).

CONCLUSION

In the current study we showed that VKC-associated KC patients have significantly longer AL and VD when compared with KC patients without VKC. Posterior segment elongation in VKC-KC group may be associated with the type IV collagen destruction due to chronic longstanding inflammation in VKC patients.

Management of vernal keratoconjunctivitis

Vernal keratoconjunctivitis (VKC) is a relatively rare, chronic form of ocular allergy that can potentially cause severe visual complications. Affecting mainly children and young adults, it is an IgE- and T cell-mediated disease, leading to a chronic inflammation in which eosinophil, lymphocyte and structural cell activation are involved. Treatment of VKC requires a multiple approach that includes conservative measures and pharmacologic treatment. Patients and parents should be made aware of the long duration of disease, its chronic evolution and possible complications. Treatment should be based on the duration and frequency of symptoms and the severity of corneal involvement. Mast cell stabilizers and antihistamines have been proven to be effective for the treatment of mild to moderate forms of VKC. In the most severe cases, topical steroids can be used as rescue medication to reduce conjunctival and corneal inflammation. Immunomodulators that have been investigated for VKC treatment include topical ocular preparations of cyclosporine A and tacrolimus. Topical cyclosporine A has been proven to be effective in the long-term treatment of VKC, significantly improving signs and symptoms without significant side effects.