Immunopathological findings in conjunctival cells using immunofluorescence staining of impression cytology specimens

Aberrant HLA-DR expression in the conjunctival epithelium after autologous serum treatment in patients with graft-versus-host disease or Sjögren's syndrome

The aim of this study was to determine the effect of autologous serum (AS) eye drops on the density of human leucocyte antigen (HLA)-DR-positive epithelial cells and Langerhans cells on the ocular surface of patients with bilateral severe dry eye disease (DED) due to graft-versus-host disease (GvHD) or Sjögren’s syndrome (SS). The study was conducted on 24 patients (48 eyes). AS was applied 6–10 times daily for 3 months together with regular artificial tear therapy. HLA-DR-positive cells were detected by direct immunocytochemistry on upper bulbar conjunctiva imprints obtained before and after treatment. The application of AS drops led to a statistically significant increase in the mean density of aberrant HLA-DR-positive conjunctival epithelial cells (p < 0.05) and HLA-DR-positive Langerhans cells (p < 0.05) in the GvHD group. Aberrant HLA-DR-positive epithelial cells in the SS group were decreased non-significantly. All patients reported a significant decrease in the Ocular Surface Disease Index (p < 0.01), which indicates improvement of the patient’s subjective feelings after therapy. There was an expected but non-significant decrease of aberrant HLA-DR-positive conjunctival epithelial cells in the SS group only. However, the increased density of HLA-DR-positive cells, indicating slight subclinical inflammation, does not outweigh the positive effect of AS in patients with DED from GvHD.

Characterisation of corneal impression cytology in dogs and its application in the diagnosis of keratoconjunctivitis sicca

OBJECTIVE

Determine morphological and morphometric parameters of corneal epithelium in dogs, and determine the cellular alterations that occur in canine keratoconjunctivitis sicca (KCS) using impression cytology.

STUDY ANIMALS

60 dogs divided into two groups: dogs with Schirmer tear test (STT) at least 15 mm/minute and absence of ocular disease, and dogs with STT less than 15 mm/minute and clinical signs of KCS.

PROCEDURES

Impression cytology was used to collect corneal samples. The percentage of eyes with cell changes, the number of such cells and the percentage of cells with structural alterations in each group were determined. The possible correlation between corneal epithelium alterations and decreased tear production was evaluated.

RESULTS

A significant positive correlation existed between STT and the area of the cytoplasm and nucleus of corneal cells. A significant negative correlation was found between STT ​​and the nucleus/cytoplasm ratio, and the presence of cellular changes. A significant difference existed between the numbers of pyknotic nuclei, being higher among animals with all stages of KCS.

CONCLUSION

Corneal impression cytology can be used to assess the corneal epithelium in healthy eyes and eyes with KCS, demonstrating its usefulness as a diagnostic tool especially in mild and early cases.

Relationship Between Ocular Surface Epithelial Damage, Tear Abnormalities, and Blink in Patients With Dry Eye

PURPOSE

Considering that tears play the role of a lubricant, it is speculated that in the pathophysiology of dry eye, increased friction during blinking results in corneal and conjunctival damage, which may subsequently affect the blink. The purpose of this study was to investigate the relationship between ocular surface epithelial damage, tear abnormalities, and blinks in patients with dry eye.

METHODS

This study involved 45 eyes of 45 female patients with dry eye (mean age: 57.6 years). In all eyes, tear meniscus radius (mm), spread grade of the tear film lipid layer (SG: 1-5: 1 being the best), fluorescein breakup time (FBUT, seconds), corneal and bulbar conjunctival epithelial damage (CED: 15 points maximum and CONJUNCTIVAL EPITHELIAL DAMAGE (CjED): 6 points maximum, respectively), and Schirmer I test (ST1, mm) were evaluated. Blink rate (BR, blinks per minute), palpebral aperture height (mm), upper-eyelid opening-phase amplitude/upper-eyelid closing-phase amplitude (mm), upper-eyelid opening-phase duration/upper-eyelid closing-phase duration (ms), and upper-eyelid opening-phase maximum velocity/upper-eyelid closing-phase maximum velocity (mm/s) were measured using a custom-made high-speed blink analyzer. Finally, the factors that determine CED and CjED were investigated by multiple regression analysis, in which the parameters were chosen using the stepwise procedure.

RESULTS

CED and CjED were found to be described as 2.687 + (1.816 × SG) - (0.937 × FBUT) (R = 0.656, P < 0.0001) and 0.684 + (0.801 × SG) - (0.526 × FBUT) - (0.041 × ST1) + (0.010 × upper-eyelid closing-phase maximum velocity) (R = 0.714, P < 0.0001), respectively.

CONCLUSIONS

Although CED was significantly related to only tear abnormalities, CjED was significantly related to tear abnormalities and blinking.

[Prevention and treatment of degenerative changes in ocular surface epithelium in patients with dry eye syndrome]

In current understanding of the pathogenesis of xerotic changes of the ocular surface in patients with dry eye syndrome (DES), great importance is given to hyperosmolarity of the tear film, inflammatory process and oxidative stress. By now, no convincing data has been obtained on whether the oxidative stress is primary in relation to the inflammatory process in the ocular surface tissues, or if it is a complication. Furthermore, in the complex treatment of patients with DES, antioxidant therapy has so far received little attention. This problem can be solved with the 'artificial tears' preparation containing cyanocobalamin (vitamin B12), which antioxidant, anti-inflammatory and clinical effectiveness has been convincingly proved in a number of experimental and clinical studies of recent years. Improving the methods of vital diagnostics of xerosis of the ocular surface also enables detection of subclinical changes in epithelium of the cornea and conjunctiva, thus allowing timely prescription of metabolic therapy. One of the promising directions of such treatment is the use of 5% dexpanthenol, which stimulates the processes of reparative regeneration and possesses an anti-inflammatory effect.

Reconsidering the central role of mucins in dry eye and ocular surface diseases

Mucins are key actors in tear film quality and tear film stability. Alteration of membrane-bound mucin expression on corneal and conjunctival epithelial cells and/or gel-forming mucin secretion by goblet cells (GCs) promotes in ocular surface diseases and dry eye disease (DED). Changes in the mucin layer may lead to enhanced tear evaporation eventually contributing to tear hyperosmolarity which has been associated with ocular surface inflammation. Inflammatory mediators in turn may have a negative impact on GCs differentiation, proliferation, and mucin secretion. This sheds new light on the position of GCs in the vicious circle of DED. As contributor to ocular surface immune homeostasis, GC loss may contribute to impaired ocular surface immune tolerance observed in DED. In spite of this, there are no tools in routine clinical practice for exploring ocular surface mucin deficiency/dysregulation. Therefore, when selecting the most appropriate treatment options, there is a clear unmet need for a better understanding of the importance of mucins and options for their replacement. Here, we comprehensively revisited the current knowledge on ocular surface mucin biology, including functions, synthesis, and secretion as well as the available diagnostic tools and treatment options to improve mucin-associated homeostasis. In particular, we detailed the potential link between mucin dysfunction and inflammation as part of the uncontrolled chronic inflammation which perpetuates the vicious circle in DED.

Clinical impact of inflammation in dry eye disease: proceedings of the ODISSEY group meeting

Dry eye disease (DED) is a common, multifactorial ocular condition with major impact on vision and quality of life. It is now well recognized that the pathophysiology of chronic DED can include a cycle of inflammation involving both innate and adaptive immune responses. Recently, in vitro/in vivo models have been used to obtain a better understanding of DED‐related inflammatory processes at molecular/cellular levels although they do not truly reproduce the complex and chronic hallmarks of human DED. In clinical DED research, advanced techniques such as impression cytology, conjunctival biopsy, in vivo confocal microscopy and multiplex tear analyses have allowed an improved assessment of inflammation in DED patients. This was supported by the identification of reliable inflammatory markers including matrix metalloproteinase‐9, human leucocyte antigen‐DR or intercellular adhesion molecule‐1 in tears and impression cytology samples. One of the current therapeutic strategies focuses on breaking the inflammatory cycle perpetuating the ocular surface disease, and preclinical/clinical research has led to the development of promising anti‐inflammatory compounds. For instance, cyclosporine, already approved in the United States, has recently been authorized in Europe to treat DED associated with severe keratitis. In addition, other agents such as corticosteroids, doxycycline and essential fatty acids, through their anti‐inflammatory properties, show encouraging results. We now have a clearer understanding of the inflammatory processes involved in DED, and there is hope that the still emerging preclinical/clinical findings will be translated into new and highly effective therapies for patients in the near future.

Elevation of autophagy markers in Sjögren syndrome dry eye

Autophagy is known to be implicated in the pathogenesis of Sjögren syndrome (SS), but evidences are limited. We aimed to examine the levels of autophagy markers in tear film and conjunctival epithelial cells from SS dry eye patients, and analyze their correlations with clinical features. Patients with SS dry eye exhibited lower Schirmer values, lower tear breakup time, and higher ocular staining scores. In tears, ATG5 and LC3B-II/I levels were significantly higher in SS dry eye. ATG5 and LC3B-II mRNA in the conjunctiva were also elevated in SS dry eye compared with non-SS dry eye. The immunostaining of conjunctival epithelium showed a punctate pattern of ATG5 and LC3B-II in SS dry eye. These staining patterns were also observed in the lacrimal gland of SS animal models. ATG5 levels in tears and the conjunctival epithelium strongly correlated with ocular staining scores, and one month of topical corticosteroid treatment reduced both ATG5 and LC3B-II/I levels in tear film and the conjunctival epithelium of patients with SS dry eye. Our results suggest that autophagy is enhanced or dysregulated in SS and autophagy markers may be serve as both diagnostic and therapeutic biomarkers in SS dry eye.

Biomarkers of ocular surface disease using impression cytology

Impression cytology (IC) is a technique which permits the retrieval of the outermost layer of ocular surface cells via the use of various types of filters. It is a minimally invasive method of evaluating human conjunctival epithelial cell morphology in the diagnosis of dry eye disease, a common and distressing disorder associated with ageing, contact lens wear, autoimmune disorders and refractive (LASIK) surgery. IC may also be utilized in the diagnosis of other ocular diseases, such as keratoconus and thyroid orbitopathy. More recently, IC has been utilized for the subsequent investigation of gene and protein expression of conjunctival cells in order to identify novel diagnostic biomarkers and to further our understanding of the mechanisms underlying ocular surface disease. This review will therefore examine the literature concerning the role of IC in identifying cellular markers of eye disease, systemic diseases with ocular involvement and potential novel therapeutic targets.

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

PURPOSE

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

DESIGN

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Growing Need for Validated Biomarkers and Endpoints for Dry Eye Clinical Research

Purpose

Biomarkers with minimally invasive and reproducible objective metrics provide the key to future paradigm shifts in understanding of the underlying causes of dry eye disease (DED) and approaches to treatment of DED. We review biomarkers and their validity in providing objective metrics for DED clinical research and patient care.

Methods

The English-language literature in PubMed primarily over the last decade was surveyed for studies related to identification of biomarkers of DED: (1) inflammation, (2) point-of-care, (3) ocular imaging, and (4) genetics. Relevant studies in each group were individually evaluated for (1) methodological and analytical details, (2) data and concordance with other similar studies, and (3) potential to serve as validated biomarkers with objective metrics.

Results

Significant work has been done to identify biomarkers for DED clinical trials and for patient care. Interstudy variation among studies dealing with the same biomarker type was high. This could be attributed to biologic variations and/or differences in processing, and data analysis. Correlation with other signs and symptoms of DED was not always clear or present.

Conclusions

Many of the biomarkers reviewed show the potential to serve as validated and objective metrics for clinical research and patient care in DED. Interstudy variation for a given biomarker emphasizes the need for detailed reporting of study methodology, including information on subject characteristics, quality control, processing, and analysis methods to optimize development of nonsubjective metrics. Biomarker development offers a rich opportunity to significantly move forward clinical research and patient care in DED.

Overview

DED is an unmet medical need - a chronic pain syndrome associated with variable vision that affects quality of life, is common with advancing age, interferes with the comfortable use of contact lenses, and can diminish results of eye surgeries, such as cataract extraction, LASIK, and glaucoma procedures. It is a worldwide medical challenge with a prevalence rate ranging from 8% to 50%. Many clinicians and researchers across the globe are searching for better answers to understand the mechanisms related to the development and chronicity of DED. Though there have been many clinical trials for DED, few new treatments have emerged over the last decade. Biomarkers may provide the needed breakthrough to propel our understanding of DED to the next level and the potential to realize our goal of truly personalized medicine based on scientific evidence. Clinical trials and research on DED have suffered from the lack of validated biomarkers and less than objective and reproducible endpoints. Current work on biomarkers has provided the groundwork to move forward. This review highlights primarily ocular biomarkers that have been investigated for use in DED, discusses the methodologic outcomes in providing objective metrics for clinical research, and suggests recommendations for further work.

In Vitro Inhibition of NFAT5-Mediated Induction of CCL2 in Hyperosmotic Conditions by Cyclosporine and Dexamethasone on Human HeLa-Modified Conjunctiva-Derived Cells

Purpose

To investigate the pro-inflammatory intracellular mechanisms induced by an in vitro model of dry eye disease (DED) on a Hela-modified conjunctiva-derived cells in hyperosmolarity (HO) stress conditions. This study focused on CCL2 induction and explored the implications of the nuclear factor of activated T-cells 5 (NFAT5) as well as mitogen-activated protein kinases (MAPK) and nuclear factor kappa B (NFĸB). This work was completed by an analysis of the effects of cyclosporine A (CsA), dexamethasone (Dex) and doxycycline (Dox) on HO-induced CCL2 and NFAT5 induction.

Methods

A human HeLa-modified conjunctiva-derived cell line was cultured in NaCl-hyperosmolar medium for various exposure times. Cellular viability, CCL2 secretion, NFAT5 and CCL2 gene expression, and intracytoplasmic NFAT5 were assessed using the Cell Titer Blue^® assay, enzyme-linked immunosorbent assay (ELISA), RT-qPCR and immunostaining, respectively. In selected experiments, inhibitors of MAPKs or NFκB, therapeutic agents or NFAT5 siRNAs were added before the hyperosmolar stimulations.

Results

HO induced CCL2 secretion and expression as well as NFAT5 gene expression and translocation. Adding NFAT5-siRNA before hyperosmolar stimulation led to a complete inhibition of CCL2 induction and to a decrease in cellular viability. p38 MAPK (p38), c-Jun NH₂-terminal kinase (JNK) and NFĸB inhibitors, CsA and Dex induced a partial inhibition of HO-induced CCL2, while Dox and extracellular signal-regulated kinase (ERK) inhibitor did not. Dex also induced a partial inhibition of HO-induced NFAT5 gene expression but not CsA or Dox.

Conclusions

These in vitro results suggest a potential role of CCL2 in DED and highlight the crucial role of NFAT5 in the pro-inflammatory effect of HO on HeLa-modified conjunctiva-derived cells, a rarely studied cellular type. This inflammatory pathway involving NFAT5 and CCL2 could offer a promising target for developing new therapies to treat DED, warranting further investigations to fully grasp the complete intracellular mechanisms.

Evaluation of a Novel Artificial Tear in the Prevention and Treatment of Dry Eye in an Animal Model

Purpose: To evaluate effects of a novel multi-ingredient artificial tear formulation containing carboxymethylcellulose (CMC) and hyaluronic acid (HA) in a murine dry eye model.

Methods: Dry eye was induced in mice (C57BL/6) using an intelligently controlled environmental system (ICES). CMC+HA (Optive Fusion™), CMC-only (Refresh Tears^®), and HA-only (Hycosan^®) artificial tears and control phosphate-buffered saline (PBS) were administered 4 times daily and compared with no treatment (n = 64 eyes per group). During regimen 1 (prevention regimen), mice were administered artificial tears or PBS for 14 days (starting day 0) while they were exposed to ICES, and assessed on days 0 and 14. During regimen 2 (treatment regimen), mice exposed to ICES for 14 days with no intervention were administered artificial tears or PBS for 14 days (starting day 14) while continuing exposure to ICES, and assessed on days 0, 14, and 28. Corneal fluorescein staining and conjunctival goblet cell density were measured.

Results: Artificial tear-treated mice had significantly better outcomes than control groups on corneal staining and goblet cell density (P < 0.01). Mice administered CMC+HA also showed significantly lower corneal fluorescein staining and higher goblet cell density, compared with CMC (P < 0.01) and HA (P < 0.05) in both regimens 1 and 2.

Conclusions: The artificial tear formulation containing CMC and HA was effective in preventing and treating environmentally induced dry eye. Improvements observed for corneal fluorescein staining and conjunctival goblet cell retention suggest that this combination may be a viable treatment option for dry eye disease.

Rethinking dry eye disease: a perspective on clinical implications

Publication of the DEWS report in 2007 established the state of the science of dry eye disease (DED). Since that time, new evidence suggests that a rethinking of traditional concepts of dry eye disease is in order. Specifically, new evidence on the epidemiology of the disease, as well as strategies for diagnosis, have changed the understanding of DED, which is a heterogeneous disease associated with considerable variability in presentation. These advances, along with implications for clinical care, are summarized herein. The most widely used signs of DED are poorly correlated with each other and with symptoms. While symptoms are thought to be characteristic of DED, recent studies have shown that less than 60% of subjects with other objective evidence of DED are symptomatic. Thus the use of symptoms alone in diagnosis will likely result in missing a significant percentage of DED patients, particularly with early/mild disease. This could have considerable impact in patients undergoing cataract or refractive surgery as patients with DED have less than optimal visual results. The most widely used objective signs for diagnosing DED all show greater variability between eyes and in the same eye over time compared with normal subjects. This variability is thought to be a manifestation of tear film instability which results in rapid breakup of the tearfilm between blinks and is an identifier of patients with DED. This feature emphasizes the bilateral nature of the disease in most subjects not suffering from unilateral lid or other unilateral destabilizing surface disorders. Instability of the composition of the tears also occurs in dry eye disease and shows the same variance between eyes. Finally, elevated tear osmolarity has been reported to be a global marker (present in both subtypes of the disease- aqueous-deficient dry eye and evaporative dry eye). Clinically, osmolarity has been shown to be the best single metric for diagnosis of DED and is directly related to increasing severity of disease. Clinical examination and other assessments differentiate which subtype of disease is present. With effective treatment, the tear osmolarity returns to normal, and its variability between eyes and with time disappears. Other promising markers include objective measures of visual deficits, proinflammatory molecular markers and other molecular markers, specific to each disease subtype, and panels of tear proteins. As yet, however, no single protein or panel of markers has been shown to discriminate between the major forms of DED. With the advent of new tests and technology, improved endpoints for clinical trials may be established, which in turn may allow new therapeutic agents to emerge in the foreseeable future. Accurate recognition of disease is now possible and successful management of DED appears to be within our grasp, for a majority of our patients.

HLA-DR expression as a biomarker of inflammation for multicenter clinical trials of ocular surface disease

There are currently no validated minimally invasive objective metrics for the classification and evaluation of ocular surface diseases and/or for evaluating treatment efficacy. We thus sought to establish a standardized methodology for determining the relative amount of the inflammatory biomarker HLA-DR on the ocular surface and to evaluate the precision, reliability and repeatability of its use for large multicenter clinical trials and translational research studies of ocular surface disease. Multiple studies were conducted to establish a Standard Operating Procedure (SOP) for utilizing HLA-DR expression as a minimally invasive, objective, ocular surface inflammatory biomarker. The established SOPs provide specific guidelines for HLA-DR collection and analysis, in order to incorporate it reliably into multicenter clinical trials and/or translational research. Duplicate cell samples from impression cytology (IC) samples of both normal and dry eye individuals were collected and split to assess repeatability (between the splits and between the duplicate samples). To determine storage capability, one duplicate was stained immediately and the other after 30 days cold storage. To demonstrate the feasibility of the use of the SOP for a multicenter clinical trial, clinicians out-of-state were trained to collect IC samples, and the samples shipped to our Biomarker Laboratory, logged, processed and analyzed. Demonstration of the ability to incorporate of IC into a randomized double masked clinical trial of dry eye disease (DED) was performed. In all cases, processing and analyses were performed by a masked independent observer. The validity/viability of the SOPs was established by demonstrating that: 1) sufficient numbers of cells can be collected via IC; 2) the precision/repeatability of the relative biomarker expression quantified in samples; 3) personnel at distant sites can be taught to collect, store and ship samples successfully; 4) samples can be stored for up to 30 days (refrigeration) before processing without affecting results; 5) IC can be incorporated into a double blind randomized clinical trial (RCT) of DED; and 6) the Biomarker Laboratory can track a large number of masked samples reliably. In conclusion, our standard operating procedure for impression cytology analysis of HLA-DR expression appears to be repeatable and reproducible for use in multicenter clinical trials, providing a minimally invasive objective biomarker of inflammation of the ocular surface.

The dominant human conjunctival epithelial CD8αβ+ T cell population is maintained with age but the number of CD4+ T cells increases

The conjunctiva is a highly specialized ocular mucosal surface that, like other mucosa, houses a number of leukocyte populations. These leukocytes have been implicated in age-related inflammatory diseases such as dry-eye, but their phenotypic characteristics remain largely undetermined. Existing literature provides rudimentary data from predominantly immunohistochemical analyses of tissue sections, prohibiting detailed and longitudinal examination of these cells in health and disease. Using recovered cells from ocular surface impression cytology and flow cytometry, we examined the frequency of leukocyte subsets in human conjunctival epithelium and how this alters with age. Of the total CD45+ leukocyte population within the conjunctival epithelium, 87% [32-99] (median) [range] comprised lymphocytes, with 69% [47-90] identified as CD3 + CD56- T cells. In contrast to peripheral blood, the dominant conjunctival epithelial population was TCRαβ + CD8αβ + (80% [37-100]) with only 10% [0-56%] CD4+ cells. Whilst a significant increase in the CD4+ population was seen with age (r = 0.5; p < 0.01) the CD8+ population remained unchanged, resulting in an increase in the CD4:CD8 ratio (r = 0.5;p < 0.01). IFNγ expression was detectable in 18% [14-48] of conjunctival CD4+ T cells and this was significantly higher among older individuals (<35 years, 7[4-39] vs. >65 years, 43[20-145]; p < 0.05). The elevation of CD4+ cells highlights a potentially important age-related alteration in the conjunctival intra-epithelial leukocyte population, which may account for the vulnerability of the aging ocular surface to disease.

Research on the stability of a rabbit dry eye model induced by topical application of the preservative benzalkonium chloride

Background

Dry eye is a common disease worldwide, and animal models are critical for the study of it. At present, there is no research about the stability of the extant animal models, which may have negative implications for previous dry eye studies. In this study, we observed the stability of a rabbit dry eye model induced by the topical benzalkonium chloride (BAC) and determined the valid time of this model.

Methods and Findings

Eighty white rabbits were randomly divided into four groups. One eye from each rabbit was randomly chosen to receive topical 0.1% BAC twice daily for 2 weeks (Group BAC-W2), 3 weeks (Group BAC-W3), 4 weeks (Group BAC-W4), or 5 weeks (Group BAC-W5). Fluorescein staining, Schirmer's tests, and conjunctival impression cytology were performed before BAC treatment (normal) and on days 0, 7, 14 and 21 after BAC removal. The eyeballs were collected at these time points for immunofluorescence staining, hematoxylin and eosin (HE) staining, and electron microscopy. After removing BAC, the signs of dry eye in Group BAC-W2 lasted one week. Compared with normal, there were still significant differences in the results of Schirmer's tests and fluorescein staining in Groups BAC-W3 and BAC-W4 on day 7 (P<0.05) and in Group BAC-W5 on day 14 (P<0.05). Decreases in goblet cell density remained stable in the three experimental groups at all time points (P<0.001). Decreased levels of mucin-5 subtype AC (MUC5AC), along with histopathological and ultrastructural disorders of the cornea and conjunctiva could be observed in Group BAC-W4 and particularly in Group BAC-W5 until day 21.

Conclusions

A stable rabbit dry eye model was induced by topical 0.1% BAC for 5 weeks, and after BAC removal, the signs of dry eye were sustained for 2 weeks (for the mixed type of dry eye) or for at least 3 weeks (for mucin-deficient dry eye).

Fluorescein punctate staining traced to superficial corneal epithelial cells by impression cytology and confocal microscopy

PURPOSE

The basis of fluorescein-associated superficial punctate staining in dry eyes is controversial. Prior explanations include fluorescein pooling in surface erosive defects, intercellular trapping of fluorescein, and intracellular staining in dead cells. In this study, the hypothesis that punctate erosions are individual cells with enhanced fluorescence was tested.

METHODS

Ten impression cytology membrane materials were compared, to optimize cellular yield in buccal mucosa and cornea. Clinicocytologic correlation of punctate fluorescent spots was performed in four dry eye patients. Individual punctate spots were localized by fiducial marks in photographs, before and after removal with impression membranes, and were traced in fluorescence microscopy and cytologic staining. Two-way contingency table analysis was used to determine the correlation of punctate spots with cells removed by the membrane. Clinicopathologic correlation of punctate spots was performed in 10 corneas removed in dry eye patients by transplantation for concurrent diseases. Punctate fluorescence was tracked in specimens by fiducial marks and epifluorescence. The distribution of fluorescent spots in specific cell layers of the cornea was determined by confocal microscopy.

RESULTS

Cellular yield was greatest with impressions from polytetrafluoroethylene (PTFE [Teflon]; BioPore; Millipore, Billerica, MA) membrane compared with its closest rival (P = 0.019). Punctate fluorescent spots, most of which disappeared after impression cytology (71%), correlated with cells on the membranes (P = 0.009). The punctate spots were more frequent in the superficial cell layers of the cornea (80%) compared with the deepest two layers (0%) (P < 0.00049).

CONCLUSIONS

Punctate epithelial erosions correspond to enhanced fluorescence in epithelial cells predominantly in superficial layers of the cornea and would be more aptly named fluorescent epithelial cells (FLECs).

Dendritic cell physiology and function in the eye

The eye and the brain are immunologically privileged sites, a property previously attributed to the lack of a lymphatic circulation. However, recent tracking studies confirm that these organs have good communication through classical site-specific lymph nodes, as well as direct connection through the blood circulation with the spleen. In addition, like all tissues, they contain resident myeloid cell populations that play important roles in tissue homeostasis and the response to foreign antigens. Most of the macrophage and dendritic cell (DC) populations in the eye are restricted to the supporting connective tissues, including the cornea, while the neural tissue (the retina) contains almost no DCs, occasional macrophages (perivascularly distributed), and a specialized myeloid cell type, the microglial cell. Resident microglial cells are normally programmed for immunological tolerance. The privileged status of the eye, however, is relative, as it is susceptible to immune-mediated inflammatory disease, both infectious and autoimmune. Intraocular inflammation (uveitis and uveoretinitis) and corneal graft rejection constitute two of the more common inflammatory conditions affecting the eye leading to considerable morbidity (blindness). As corneal graft rejection occurs almost exclusively by indirect allorecognition, host DCs play a major role in this process and are likely to be modified in their behavior by the ocular microenvironment. Ocular surface disease, including allergy and atopy, also comprise a significant group of immune-mediated eye disorders in which DCs participate, while infectious disease such as herpes simplex keratitis is thought to be initiated via corneal DCs. Intriguingly, some more common conditions previously thought to be degenerative (e.g. age-related macular degeneration) may have an autoimmune component in which ocular DCs and macrophages are critically involved. Recently, the possibility of harnessing the tolerizing potential of DCs has been applied to experimental models of autoimmune uveoretinitis with good effect. This approach has considerable potential for use in translational clinical therapy to prevent sight-threatening disease caused by ocular inflammation.

Do antiglaucomatous prostaglandins induce melanogenesis in human conjunctiva?: an impression cytology pilot study

PURPOSE

To determine the effect of antiglaucomatous prostaglandin analogs on conjunctival melanogenesis.

METHODS

For this pilot study, 30 glaucomatous patients treated with prostaglandin drops (alone and in association to beta-blockers) and 30 control subjects (15 healthy volunteers and 15 patients treated with beta-blockers) were included in this transversal, single masked, case-control, observational study. Skin complexion, eye color, conjunctival pigmentation, lacrimal tests, and corneal fluorescein staining were evaluated. Immunoreactivity for Tyrosinase was assayed on conjunctival imprints.

RESULTS

Twenty percent of patients treated with prostaglandins and 10% of the control subjects clinically manifested conjunctival pigmentation (P=0.279). Only 4% (8/198) of the conjunctival specimens were positive to Tyrosinase immunostaining, with no statistically significant difference among the groups (P=0.449). In all cases, the proportion of positive cells was below 4%. When compared with subjects having negative specimens, those with positive immunostains did not show any statistically significant difference in skin complexion, eye color or exposure to irritants, and ultraviolet (P>0.05).

CONCLUSIONS

According to our preliminary results, prostaglandin antiglaucomatous analogs do not significantly enhance pigmentation in the superficial layers of the conjunctiva. The existence of the Tyrosinase enzyme in the superficial layers of the conjunctiva suggests that basal melanocytes may transfer their melanogenic apparatus to superficial epithelial cells.

Immune mechanisms in allergic eye diseases: what is new?

PURPOSE OF REVIEW

The purpose of this review will be to focus on new findings that expand our understanding of the immune mechanisms occurring in the various forms of allergic eye disease and in experimental models, and some novel therapeutic approaches.

RECENT FINDINGS

The novel data encompass three main areas: effector mechanisms in allergic eye disease; cytokines and chemokines in conjunctival responses; combinations of drugs for improving treatment options for allergic eye disease.

SUMMARY

The term 'allergic eye disease' describes a spectrum of clinical conditions, ranging from the common, milder conditions of seasonal and perennial allergic conjunctivitis (SAC, PAC), to the rare and more severe diseases, vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC). These latter two diseases can involve the cornea, leading to impaired vision. Although there is an underlying allergic mechanism, each of these ocular surface conditions involves different cellular responses and much effort has been made to identify the molecular pathways, which could be used as potential targets for therapeutic intervention. Currently available drugs, in particular for chronic forms of disease, are inadequate and there is an urgent need for safer, more localized and effective treatment.

Impression cytology: recent advances and applications in dry eye disease

Impression cytology (IC) allows cells to be harvested from the ocular surface noninvasively. Superficial layers of the epithelium are removed by application of cellulose acetate filters or Biopore membranes, and the cells can be subsequently analyzed by various methods, depending on the objective of the investigation or pathology involved. IC techniques are easily learned, can be performed in an outpatient setting, and cause virtually no discomfort to the patient. IC facilitates the diagnosis of ocular surface disorders, including, among others, keratoconjunctivitis sicca, ocular surface squamous neoplasia, and ocular surface infections. During the past decade, IC has been used increasingly to assist in diagnosis of ocular surface disease, improve our understanding of the pathophysiology of ocular surface disease, and provide biomarkers to be used as outcome measures in clinical trials. Dry eye disease is one area in which IC has contributed to significant advances.

Tear cytokine profiles in dysfunctional tear syndrome

PURPOSE

To compare tear cytokine and chemokine concentrations in asymptomatic control and Dysfunctional Tear syndrome (DTS) patients and determine the correlations between tear inflammatory mediators and clinical severity.

DESIGN

Prospective observational cohort study.

METHODS

Concentrations of epidermal growth factor (EGF), interleukin (IL)-1 alpha (1alpha), 1 beta (1beta), 6, 10, 12, and 13, interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and chemokines: IL-8 (CXC); macrophage inflammatory protein-1 alpha (MIP-1alpha) (CCL3); and regulated upon activation, normal T-cell expressed and secreted (RANTES CCL5) were measured by a multiplex immunobead assay in an asymptomatic control group and DTS patients with and without meibomian gland disease (MGD). Spearman correlations between tear cytokines and severity of irritation symptoms and ocular surface signs were calculated.

RESULTS

Tear concentrations of IL-6, IL-8 and TNF-alpha were significantly higher in DTS with and without MGD and EGF was significantly reduced in the DTS without MGD group compared with the control group. MIP-1alpha was greater in entire DTS and DTS without MGD groups than the control group and RANTES was greater in DTS with MGD than the control and DTS without MGD groups. IL-12 was significantly higher in the DTS with MGD than the DTS without MGD subgroup. Significant correlations were observed between IL-6 and irritation symptoms and between a number of cytokines and chemokines and clinical parameters.

CONCLUSIONS

As predicted, patients with DTS have higher levels of inflammatory mediators in their tears that show correlation with clinical disease parameters. Furthermore, different tear cytokine/chemokine profiles were observed in DTS patients with and without MGD groups.

Filtering blebs and aqueous pathway an immunocytological and in vivo confocal microscopy study

OBJECTIVE

To characterize and understand, at the cellular level, the aqueous humor pathways after filtering surgery, using in vivo confocal microscopy and impression cytology (IC).

DESIGN

Observational case series.

PARTICIPANTS

Thirty-two blebs of 29 patients after trabeculectomy were retrospectively evaluated.

METHODS

In vivo confocal microscopy and immunofluorescence staining of IC samples taken on and around the bleb area were performed. Impression cytology samples were examined under confocal microscopy after goblet cell and inflammatory cell immunostaining with anti-MUC5AC and antivimentin antibodies, respectively. Eyes were classified into 3 groups: (1) functioning blebs (11 eyes), (2) nonfunctioning blebs (10 eyes), and (3) functioning blebs after mitomycin C application (12 eyes). Impression cytology specimens and in vivo confocal microscopy images were analyzed and compared in a masked manner.

MAIN OUTCOME MEASURES

Conjunctival epithelium changes of each type of bleb were analyzed using both impression cytology specimens and in vivo confocal microscopy and correlated to clinical outcomes.

RESULTS

In all IC specimens, numerous MUC5AC-positive cells were observed outside the edges of the blebs. Few MUC5AC-positive cells were observed at the surface of nonfunctioning blebs. Numerous goblet cells with immunostaining that was weak or limited to the membrane were clearly visible morphologically at the surface of functioning blebs (with and without adjunctive mitomycin C). Using in vivo confocal microscopy, all functioning blebs showed numerous intraepithelial optically empty microcysts, whereas nonfunctioning blebs had none or only a few. All blebs contained dendritiform inflammatory cells, especially after mitomycin C application.

CONCLUSION

Impression cytology and in vivo confocal microscopy provide a new approach to filtering blebs. Microcysts observed at the surface of functioning blebs seemed to correspond to goblet cells, mostly containing aqueous humor instead of highly hydrophilic gel-forming mucins. Although this hypothesis requires further confirmation, the transcellular pathway of the aqueous humor could be hypothesized to occur at the level of goblet cells toward the ocular surface.

Influence of the eye-associated lymphoid tissue (EALT) on inflammatory ocular surface disease

Certain similarities exist in the pathophysiological processes and clinical features of advanced stages of various inflammatory ocular surface diseases, suggesting that common pathways contribute to these diseases. In this article, common pathways are analyzed with a focus on the role of the physiological resident mucosal immune system of the ocular surface, termed eye-associated lymphoid tissue (EALT). This is physiologically protective but if it is deregulated it can mediate an inflammatory immune answer. Common events in inflammatory ocular surface disease lead to a vicious circle of immune-modulated inflammation, with degenerative remodeling and loss of function.

Impression cytology of the conjunctival epithelial cells in patients with cystic fibrosis

PURPOSE

Cystic fibrosis (CF) is the most frequent lethal autosomal recessive hereditary disorder. The disease affects all secretory epithelia, including the eye, and belongs to the group of ocular surface epithelial diseases, termed keratoconjunctivitis sicca or dry eye syndrome. The aim of this study was to evaluate goblet cell population and conjunctival epithelial morphology in patients with CF.

METHODS

A total of 20 CF patients and 20 controls underwent conjunctival impression cytology.

RESULTS

Impression cytology showed conjunctival squamous metaplasia and goblet cell loss in patients with CF.

CONCLUSION

Reduced goblet cell numbers and squamous metaplasia may be indicative of a higher degree of epithelial damage of conjunctival epithelial cells in CF patients, and the presence of neutrophils is a strong sign for an inflammatory background of this disease.In view of the simple, noninvasive nature of impression cytology, this technique may prove to be an important tool for the diagnosis and monitoring of dry eye changes in CF patients.

[Ocular surface investigations in dry eye]

Dry eye is a complex clinicopathological entity involving tear film, lacrimal glands, eyelids, and a wide spectrum of ocular surface cells, including epithelial, inflammatory, immune, and goblet cells. From the tightly regulated lacrimal film functions and structure, a large variety of investigations have been developed, including tear meniscus measurements, fluorophotometry, meibometry, interference pattern analysis, evaporation rate, tear osmolarity, and thermography. Dry eye conditions also interfere with the ocular surface, causing corneal irregularities that may be explored using the techniques of videokeratography and in vivo confocal microscopy, or optical impairment, as confirmed by aberrometry. At the level of ocular surface cells, impression cytology remains a standard for assessing cell alterations. It has greatly benefited from new confocal microscopy, molecular biology, and flow cytometry techniques. Biological assessment of tear proteins or other mediators is also useful. Major limits should be acknowledged, however, such as technical issues in tear film collection, especially in dry eyes, and the lack of standardization of most measurements. Tear osmolarity, electrophoresis, and dosage of normal tear proteins, such as lysozyme or lactoferrin, remain the most useful tests. Finally, some extraocular explorations such as accessory gland biopsy or serum antinuclear antibody dosage may be useful for assessing the diagnosis of Sjögren's syndrome.

Glucosamine sulfate inhibits proinflammatory cytokine-induced icam-1 production in human conjunctival cells in vitro

PURPOSE

We investigated whether glucosamine sulfate modulates the production of ICAM-1 induced by proinflammatory cytokines and whether glucosamine sulfate inhibits leukocyte adhesion to a monolayer of human conjunctival epithelial cells stimulated with proinflammatory cytokines.

METHODS

We used flow cytometry and either primary cultured human conjunctival cells or the Chang conjunctival cell model to determine the effects of glucosamine sulfate on the production of ICAM-1 in response to tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-1beta, IL-6, TNF-alpha plus IFN-gamma, or TNF-alpha plus IL-1beta. The effects of glucosamine sulfate on the expression of the ICAM-1 gene, upregulated by various cytokines, were determined by semiquantitative reverse transcription-polymerase chain reaction. The activation and nuclear translocation of the nuclear factors NF-kappaB and STAT1 were evaluated by the transient transfection of reporter gene systems and immunocytochemistry. The influence of glucosamine-sulfate-modulated ICAM-1 on neutrophil adhesion was demonstrated in a model that measures the adherence of conjunctival cells and neutrophils.

RESULTS

TNF-alpha, IFN-gamma, and IL-1beta significantly increased the production of ICAM-1 by both primary cultured human conjunctival cells and Chang conjunctival cells. Glucosamine sulfate effectively downregulated the production of ICAM-1 induced by TNF-alpha, IFN-gamma, IL-1beta, TNF-alpha plus IFN-gamma, or TNF-alpha plus IL-1beta. This downregulation occurred through the interferon-stimulated response element, IFN-gamma activation sequence, and binding sequence of NF-kappaB at the mRNA and protein levels. Glucosamine sulfate further inhibited the nuclear translocation of p65 protein in TNF-alpha- and IL-1beta-stimulated Chang conjunctival cells and phosphorylated STAT1 in IFN-gamma-stimulated Chang conjunctival cells. Glucosamine sulfate also significantly reduced the number of neutrophils adhering to a conjunctival monolayer in response to TNF-alpha, IFN-gamma, or IL-1beta.

CONCLUSIONS

Our results suggest that glucosamine sulfate inhibits ICAM-1 production in conjunctival epithelial cells in vitro. Therefore, glucosamine sulfate might be valuable in the treatment of inflammatory ocular-surface conditions.

[Immunohistochemistry in ophthalmic pathology: applications and limitations]

We evaluate the applications of immunohistochemistry (IHC) in ophthalmic cytology and pathology. The principles of the techniques used in IHC are described. Recent improvements are highlighted, such as the polymeric labeling two-step method, tyramine signal amplification, rabbit monoclonal antibodies, and labeled nanocrystals. The results of the immunohistochemical methods are collected in bacterial and viral diseases and in tumors of the eye and its adnexa, the pathology of which varies greatly. The results in lymphomas, melanomas, and palpebral tumors were more details for practical reasons. There are widespread applications of IHC in ophthalmic pathology, extending from viral ocular and general diseases to the diagnosis of tumors. In some conditions, this technique needs to be associated with molecular biology investigations. Automation helps establish standard protocols, but IHC is a multistep diagnostic method requiring proper selection, fixation, processing, and staining procedures. From a general standpoint, good communication between pathologists and ophthalmologists is the best guarantee of satisfying results.

Comparison of Toxicological Profiles of Benzalkonium Chloride and Polyquaternium-1: An Experimental Study

PURPOSE

The aim of this study was to compare, in vivo on a rat model, two different preservatives- benzalkonium chloride (BAC) and polyquaternium-1 (PQ-1)-using new experimental approaches.

METHODS

Thirty (30) eyes of 15 male Lewis rats were used in this study. Rats were randomly divided into five groups instilled twice a day for 11 days with eye drops containing different concentrations of preservatives, 0.1% BAC, 0.5% BAC, 0.1% PQ-1, 0.5% PQ-1, and balanced salt solution (BSS) as a control. The ocular surface toxicity of these two preservatives was investigated using new in vivo experimental approaches. Slit-lamp examination, the fluorescein test, the red phenol test, impression cytology, and in vivo corneal confocal microscopy were used to evaluate the rat ocular surface after preservative instillation. Histology sections and immunohistochemistry were also examined to confirm these results.

RESULTS

Compared to PQ-1, BAC consistently and dramatically altered the corneoconjunctival surface as evaluated by slit-lamp examination, the fluorescein test, impression cytology, in vivo confocal microscopy, and histology. The 0.5% BAC solution also significantly decreased tear production compared to the control. Although 0.5% PQ-1 significantly decreased goblet cell density in comparison to the control, and some abnormalities were observed with in vivo confocal microscopy, no statistically significant differences were observed between these two groups using the tear production test, slit-lamp and fluorescein evaluation, or histology.

CONCLUSION

Using an acute rat model of ocular toxicity by comparing preservatives at high concentrations, we demonstrated in vivo that high doses of PQ-1 were much less toxic than BAC. In vivo confocal microscopy and impression cytology are new promising experimental approaches to studying the rat corneoconjunctival surface, particularly in the field of ocular surface toxicity.

Conjunctival impression cytology in pseudoexfoliative glaucoma and pseudoexfoliation syndrome

BACKGROUND

In this study, ocular surface changes and tear film functions in patients with pseudoexfoliative glaucoma (PEXG) and pseudoexfoliation (PEX) syndrome were evaluated.

METHODS

This study is a randomized, double-blind and prospective study. Conjunctival impression cytology, tear film break-up time (TFBUT) test and basal Schirmer test (BST) were performed on 45 eyes of 45 subjects with PEXG (group I), 48 eyes of 48 subjects with PEX syndrome (group 2) and 50 eyes of 50 normal subjects (group 3). Impression cytology was graded 0-III based on the shape, eosinophilic-staining cytoplasm and nucleocytoplasmic ratio of the epithelial cells, and the shape, quantity and Periodic Acid Schiff-positive cytoplasm of the goblet cells.

RESULTS

Impression cytology grading scores were 6.7% grade 0, 15.6% grade I, 37.7% grade II and 40% grade III in group 1, 6.3%, 18.7%, 43.8% and 31.2% in group 2 and 38%, 36.0%, 20% and 6% in group 3, respectively. The scores in groups 1 and 2 were significantly higher than in group 3 (P = 0.001, chi(2) = 39.84). The mean values of TFBUT of groups 1, 2 and 3 were 5.91 +/- 3.27, 7.39 +/- 4.82, 10.96 +/- 3.81 s and the mean values of BST were 7.82 +/- 3.56, 9.04 +/- 4.60 and 12.50 +/- 5.25 mm/5 min, respectively. The values of TFBUT and BST were lower in groups 1 and 2 than in group 3 (P = 0.001).

CONCLUSION

The conjunctival changes in PEX and PEXG patients recorded in this study may explain the existence of tear film abnormalities in these patients. It has been shown that PEXG and PEX syndrome cause conjunctival surface changes and reduction of tear film functions.

Conjunctival epithelium improvement after systemic pilocarpine in patients with Sjogren's syndrome

AIM

To evaluate the effect of oral pilocarpine treatment on conjunctival epithelium of patients with Sjögren's syndrome (SS).

METHODS

15 primary SS patients were included in this prospective, single masked, comparative study. Patients underwent oral pilocarpine treatment for 2 months and were studied before (T0) and after 1 month (T1), 2 months (T2), and 15 days after treatment suspension (T3). Systemic and ocular symptoms, tear film break up time (BUT), corneal fluorescein vital staining, Schirmer I test, tear basal secretion test, and conjunctival imprinting were performed. Student's t test and Mann-Whitney U test were used for statistics.

RESULTS

The conjunctival imprinting showed an increase of goblet cells number at T1 (1.6 (1.2) v 0.6 (0.7) at T0, p = 0.025) improving at T2 (5.1 (1.7); p<0.001 v T0 and T1). At T3 the number of goblet cells significantly decreased (1.9 (1.1); p<0.001 v T2). An improvement of dry mouth started at T1 and returned towards baseline values at T3. For ocular symptoms, burning and foreign body sensation were improved at T1 while ocular dryness improved at T2. BUT showed a statistically significant improvement at T2.

CONCLUSIONS

Oral pilocarpine induced an increase in goblet cells number and an amelioration of conjunctival epithelium not dependent on tear secretion.

Toll-like receptor 2 expression on human conjunctival epithelial cells: a pathway for Staphylococcus aureus involvement in chronic ocular proinflammatory responses

BACKGROUND

Staphylococcus aureus colonization is common in atopic keratoconjunctivitis, potentially activating epithelial cells via toll-like receptor 2 (TLR-2) and the receptor for platelet-activating factor (PAFR).

OBJECTIVES

To examine human conjunctival epithelial cells for the expression of TLR-2 in vitro and in vivo and to evaluate the role of TLR-2 in S aureus-mediated activation of these cells.

METHODS

Conjunctival epithelial cells isolated from cadaveric tissues were stimulated with interferon gamma (IFN-gamma) or a commercial S aureus cell wall extract (Staphylococcus aureus-CWE) (with or without anti-TLR-2 blocking antibody or PAFR antagonist) and were analyzed for tumor necrosis factor alpha (TNF-alpha) and interleukin 8 (IL-8) release; surface expression of TLR-2, intercellular adhesion molecule-1, HLA, and CD14; and TLR-2 messenger RNA expression. Ocular surface cells collected via impression cytology were examined for TLR-2 expression via flow cytometry.

RESULTS

Expression of TLR-2 was up-regulated on conjunctival epithelial cells by IFN-gamma and Staphylococcus aureus-CWE. Expression of TLR-2 messenger RNA was increased by IFN-gamma. Staphylococcus aureus-CWE up-regulated intercellular adhesion molecule 1, HLA, and CD14 expression and increased TNF-alpha and IL-8 release in a dose-dependent manner. Anti-TLR-2 significantly inhibited TNF-alpha release, whereas PAFR antagonist significantly inhibited IL-8 release. Toll-like receptor 2 was expressed on conjunctival epithelial cells from 4 of 5 patients with atopic keratoconjunctivitis, 3 of 5 with seasonal allergies, and 0 of 3 without allergies.

CONCLUSIONS

Conjunctival epithelial cells express TLR-2 and may play an active role in the chronic ocular inflammatory response to S aureus through pathways that involve TLR-2 and PAFR.

Conjunctival epithelial cell expression of interleukins and inflammatory markers in glaucoma patients treated over the long term

PURPOSE

To compare the conjunctival epithelial cell expressions of inflammatory cytokines in normal subjects and in glaucoma patients treated over the long term.

DESIGN

Case-control study.

PARTICIPANTS

A total of 69 glaucoma patients treated over the long term and 15 normal subjects with no ocular abnormality or topical treatment.

METHODS

Amongst the 69 glaucoma patients, 27 were treated with preserved beta-blockers, 24 with unpreserved 0.5% timolol, and the other 18 patients with an association of > or =2 preserved drugs. All patients were treated for more than 1 year with the same treatment, with no significant differences between groups for mean ages and durations of treatment at the time of the study. Impression cytology specimens were taken and processed for immunofluorescence techniques. Conjunctival cell expressions of HLA DR, as a standard for inflammatory level, and the interleukins IL-6, IL-8, and IL-10 were obtained and quantified using flow cytometry.

MAIN OUTCOME MEASURES

Immune markers and proinflammatory cytokines in impression cytology specimens.

RESULTS

We found a significantly increased expression of all immunoinflammatory markers and mediators in the conjunctival epithelium of glaucoma patients compared with normal eyes. Human leukocyte antigen DR was significantly higher in the 2 groups receiving preserved drugs than in the unpreserved timolol group. The 3 interleukins were similarly overexpressed in all glaucoma groups, with no significant between-groups differences except for the expression level of IL-8, which was significantly higher in the multitreatment group than in the preservative-free one.

CONCLUSIONS

The present study confirms the increased expression of immunoinflammatory markers by the conjunctival epithelium of glaucoma patients treated over the long term. The development of nontoxic preservatives or preservative-free solutions is therefore of great interest.

Efficacy and safety of 0.18% sodium hyaluronate in patients with moderate dry eye syndrome and superficial keratitis

BACKGROUND

Sodium hyaluronate (SH) is used in patients with dry eye. We evaluated the efficacy and safety of SH and carboxymethylcellulose (CMC) in the treatment of dry eye syndrome with superficial keratitis.

METHODS

A total of 22 patients with moderate dry eye and superficial keratitis were enrolled in a prospective, randomised, masked-observer, parallel-group, single-centre study. Patients were randomly assigned to a 0.18% SH or 1% CMC solution for a 2-month period. In addition to the commonly assessed parameters in patients with dry eye (among others symptoms and corneal staining with fluorescein), flow cytometry analysis of CD44, HLA DR expressions in impression cytology was investigated as a potential efficacy parameter.

RESULTS

Both treatments improved the symptoms and ocular surface and were well tolerated. SH significantly (p<0.05) decreased CD44 values compared with CMC. Comfort was significantly (P<0.05) better in the SH group than that in the CMC group throughout the study. Recovery in keratitis (type, extent and depth) and symptoms were faster in the SH group than in the CMC group. Blurred vision was reported by patients in the CMC group only.

CONCLUSIONS

SH was well tolerated and tended to show a faster efficacy than did the CMC-based formulation in patients with moderate dry eye and superficial keratitis. SH could therefore advantageously be prescribed from the early stages of dry eye disease. This study also showed that flow cytometry in impression cytology specimens is a reliable tool for exploring the ocular surface at the epithelial level and that CD44, in addition to HLA DR, could be an interesting endpoint for future trials in dry eye syndrome with products based on SH.

Impression cytology of the ocular surface: a review

PURPOSE

To historically review the technique of impression cytology as a minimally invasive diagnostic tool for ocular surface pathology.

METHODS

A comprehensive review of published literature cited in PubMed since the first description of impression cytology in 1977 up to date has been undertaken.

RESULTS

A wide range of processing methods have been adapted to the technique of impression cytology (from conjunctiva, cornea or limbus): regular light microscopy with different stainings, transmission and scanning electron microscopy, immunofluorescence, immunocytochemistry, polymerase chain reaction analysis, immunoblotting analyses, or flow cytometry. At present, it is widely used as a non-invasive alternative to the full-thickness biopsy for the obtention of epithelial cells from the ocular surface.

CONCLUSIONS

Impression cytology represents a non- or minimally invasive biopsy of the ocular surface epithelium with no side effects or contraindications. It has demonstrated to be a useful diagnostic aid for a wide variety of processes involving the ocular surface. In addition, and mainly during the last decade, its use as a research tool has experienced an enormous growth and has greatly contributed to the understanding of ocular surface pathology.

[Eye-associated lymphoid tissue (EALT) is continuously spread throughout the ocular surface from the lacrimal gland to the lacrimal drainage system]

INTRODUCTION

Components of the mucosal immune system (MALT) have been identified in the conjunctiva (as CALT) and the lacrimal drainage system (as LDALT). Their structural and functional relation with the established immune protection by the lacrimal gland is unclear.

MATERIAL AND METHODS

Macroscopically normal and complete tissues of the conjunctiva, lacrimal drainage system and lacrimal gland from human body donors were investigated by analysis of translucent whole mounts, and using histology, immunohistology as well as scanning and transmission electron microscopy.

RESULTS

A typical diffuse lymphoid tissue, composed of effector cells of the immune system (T-lymphocytes and IgA producing plasma cells) under an epithelium that contains the IgA transporter SC, is not isolated in the conjunctiva and lacrimal drainage system. It is anatomically continuous from the lacrimal gland along its excretory ducts into the conjunctiva and from there via the lacrimal canaliculi into the lacrimal drainage system. Lymphoid follicles occur in a majority (about 60%) and with bilateral symmetry. The topography of CALT corresponds to the position of the cornea in the closed eye.

CONCLUSION

These results show that the MALT of the lacrimal gland, conjunctiva and lacrimal drainage system constitute an anatomical and functional unit for immune protection of the ocular surface. Therefore it should be integrated as an "eye-associated lymphoid tissue" (EALT) into the MALT system of the body. EALT can detect ocular surface antigens by the lymphoid follicles and can supply other organs and the ocular surface including the lacrimal gland with specific effector cells via the regulated recirculation of lymphoid cells.

Flow cytometry in conjunctival impression cytology: a new tool for exploring ocular surface pathologies

Flow cytometry (FCM) is a widely used technique, not only in immunology and hematology but also in many other domains and new applications have been developed in ophthalmology, for investigating ocular surface biology and pathophysiology. Apoptosis, proteins specific of cell lineage, expression of activation or immune-related markers, proinflammatory cytokine production, multi-drug resistance and oxidative stress are some examples of possible pathways that may be explored directly using ocular surface cells removed with the non-invasive technique of impression cytology, by means of flow cytometry. Conjunctival cells are thus collected by impression cytology on a filter, fixed in paraformaldehyde and dissociated by agitation before immunostaining and FCM processing. Important observations have been made concerning Sjögren's syndrome, ocular allergy and antiglaucoma eye drop toxicity. Studies performed on impression cytology with FCM techniques confirmed inflammatory and apoptotic patterns in a large number of patients with keratoconjunctivitis sicca or receiving long-term treatments with antiglaucoma drugs, even though they did not present any clinical signs of inflammation. FCM may now be used for large multicenter clinical trials and has already contributed to a better understanding of ocular surface pathophysiology, the monitoring of new immunomodulating drugs and knowledge concerning topical drugs, as regards both efficacy and safety.

The promotion of eosinophil degranulation and adhesion to conjunctival epithelial cells by IgE-activated conjunctival mast cells

BACKGROUND

Allergen-mediated mast cell activation is a key feature of ocular allergic diseases. Evidence of eosinophil-derived mediators in tears and conjunctival biopsy specimens has been associated with chronic ocular allergic inflammation.

OBJECTIVE

To examine the role of conjunctival mast cell mediators in eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation.

METHODS

Conjunctival cells were obtained by enzymatic digestion of cadaveric conjunctival tissues. Eosinophils were obtained from peripheral blood samples using negative magnetic bead selection. The effect of IgE-activated mast cell supernates on eosinophil degranulation and adherence to epithelial cells was compared with supernates obtained from mast cells pretreated with a degranulation inhibitor (olopatadine). Eosinophil adhesion was measured by eosinophil peroxidase assay, and eosinophil degranulation was measured by eosinophil-derived neurotoxin radioimmunoassay.

RESULTS

IgE-activated conjunctival mast cell supernates stimulated adhesion of eosinophils to epithelial cells (20.4% +/- 6.3% vs 3.1% +/- 1.0%; P = .048). Degranulation was not required for this process (no effect of olopatadine). IgE-activated mast cell supernates stimulated eosinophil-derived neurotoxin release (108.89 +/- 8.27 ng/10(6) cells vs 79.45 +/- 5.21 ng/10(6) cells for controls, P = .02), which was significantly inhibited by pretreatment of mast cells with a degranulation inhibitor (79.22 +/- 4.33 ng/10(6) cells vs 61.09 +/- 5.39 ng/10(6) cells for olopatadine pretreated and untreated, respectively, P = .02).

CONCLUSIONS

Mediators released from conjunctival mast cells promote eosinophil adhesion to conjunctival epithelial cells and eosinophil degranulation. Degranulation inhibition studies suggest that different mast cell mediators are involved in regulation of these events.

Ocular surface impression cytology

Impression cytology, either using cellulose acetate strips or the Biopore membrane device, is a simple, noninvasive technique that aids in the diagnosis of several disorders of the ocular surface. These disorders include ocular surface squamous neoplasia, dry eye syndrome, limbal stem-cell deficiency, specific viral infections, vitamin A deficiency, allergic disorders, conjunctival melanosis, and malignant melanoma. Another advantage is the preservation of limbal stem cells, which occur in the basal layer of the limbal epithelium and are responsible for renewal of the corneal epithelium. The Biopore membrane device is particularly user friendly, with little expertise required and adequate specimens obtained in a very high percentage of cases. The most common applications in diagnostic ocular pathology are:(i) primary diagnosis and follow-up of ocular surface squamous neoplasia, including after therapy with topical mitomycin C. The sensitivity is high (78-87%); and (ii) dry eye syndrome where squamous metaplasia and/ or hyperkeratosis are noted. Certain limitations of the technique for diagnosis of squamous neoplasia include the fact that dysplasias are often keratinizing and may yield very few or even no dysplastic cells with impression cytology. Secondly, no definite cytologic criteria reliably distinguish invasive SCC of ocular surface from in situ disease. Other applications include the rapid specific diagnosis of ocular surface infections with herpes simplex, adeno-, and varicella zoster viruses. Impression cytology samples may also be used to obtain mRNA, cells for phenotyping by flow cytometry, and proteins for Western blotting for research studies.