Tear Hyperosmolarity Research Articles

Vitamin D Replacement Improves Tear Osmolarity in Patients with Vitamin D Deficiency

ABSTRACTBackground: Vitamin D deficiency is a common health problem worldwide. Many parts of the human eye, including the epithelium of the cornea, lens, ciliary body, and retinal pigment epithelium, as well as the corneal endothelium, ganglion cell layer, and retinal photoreceptors, contain vitamin D receptor (VDR). Dry eye is also a common health problem. An adequate tear film is required for maintaining health and function of the eye. Tear hyperosmolarity is considered to be the cause of ocular surface inflammation, symptoms, and tissue damage. It is well-documented that vitamin D has an anti-inflammatory action. We aimed to investigate the effect of vitamin D replacement on tear osmolarity in patients with vitamin D deficiency. Methods: A total of 44 patients (38 females, six males, mean age:43.5 ± 12.8 years) with vitamin D deficiency currently managed by the Endocrinology and Metabolism Department of Diskapi Training and Research Hospital in Turkey were enrolled in the study. Patients were given 50,000 units of 25(OH)D3 intramuscularly, once weekly, over a period of eight weeks. All of the patients underwent tear function osmolarity (TFO) measurement initially and eight weeks after vitamin D replacement. Demographic, anthropometric, and biochemistry data of patients were recorded. Results: The mean TFO was significantly decreased (313.7 ± 17.3 mOsm/L; 302.7 ± 14.2 mOsm/L, p<0.001) at the end of the second month; 25(OH)D3 concentrations increased from 8.3 ± 3.5 ng/mL to 68.8 ± 22.3 ng/mL (p<0.001). The mean levels of hsCRP, FPG, P were 2.5 ± 2.5 mg/L, 5.09 ± 0.48 mmol/L, 1.06 ± 0.16 mmol/L initially, and 3.8 ± 5.9 mg/L, 5.11 ± 0.68 mg/dL, 1.09 ± 0.16 mmol/L after vitamin D replacement, respectively (p>0.05). The mean Ca level was 2.37 ± 0.07 mmol/L initially and 2.35 ± 0.07 mmol/L after vitamin D replacement (p<0.05). The change of TFO was negatively correlated with the variation of 25(OH)D3 before and after replacement in patients with dry eye disease (r=–0.390, p=0.049). Conclusions: As a consequence of the presence of VDR and 1α-hydroxylase in different parts of the eye, vitamin D replacement improves tear hyperosmolarity that is considered to be induced by ocular surface inflammation.

Estimating basal rear osmolarity in normal and dry eye subjects

PurposeTear osmolarity (tOsm) is used as a measure of severity in dry eye disease (DED) and has also been proposed as an index of body hydration. Currently in DED the level of tear hyperosmolarity is compared with that of a normal population. We propose that a more valid reference point for both DED and body hydration could be acquired by measuring tOsm after a period of evaporative suppression.MethodsEight normal (N) and eight DED subjects were recruited and their tOsm measured with a TearLab® osmometer in uncontrolled environmental conditions. They then entered a controlled environment chamber (CEC) set to 23°C and 0.08 m/s airflow and, either: (1) had tOsm measured after 45 min of eye closure and then at 15 min intervals for a further 45 min at 45% relative humidity (RH), or (2) had tOsm measured every 15 min for 45 min, at 70% RH, to suppress evaporation.ResultsTear osmolality was significantly reduced after eye closure in both N and DED subjects, to levels in the range of plasma osmolarity, between 285 and 295 mOsm/L (N p = 0.03; DED p = 0.006). The tOsm rose towards the start value on eye opening. In subjects exposed to 70% RH, which was not expected to suppress evaporation completely, a fall in tOsm also occurred, but to a lesser extent than achieved with eye closure. This was significant in DED patients (p = 0.026) but not in N subjects (p = 0.12).ConclusionsAs predicted, total suppression of tear evaporation resulted in a fall in tOsm. We hypothesise that complete suppression of evaporation, for a sufficient period, drives down tOsm to a basal tear osmolarity value that will be a better measure of body hydration than tOsm measured in open eye conditions. It will also provide a personal baseline against which to gauge the severity of tear hyperosmolarity in DED patients.

Optical Coherence Tomography Reveals Changes to Corneal Reflectivity and Thickness in Individuals with Tear Hyperosmolarity.

PurposeTo investigate whether tear hyperosmolarity, a feature of dry eye disease (DED), affects central corneal thickness (CCT), corneal light reflectivity, and/or tear film reflectivity.MethodsThis prospective, cross-sectional study involved 48 participants (38 with hyperosmolar tears and 10 controls with normo-osmolar tears). Symptoms and signs of DED (tear osmolarity, sodium fluorescein tear break-up time, ocular surface staining, Schirmer test) were assessed. CCT, and the reflectivity of the cornea and the tear-epithelial interface were quantified relative to background noise using Fourier-domain optical coherence tomography (FD-OCT).ResultsCCT of eyes with severe tear hyperosmolarity, defined as eyes in the upper quartile of the hyperosmolar group, was less than control eyes (539.1 ± 7.4 vs. 583.1 ± 15.0 μm, P = 0.02) and eyes with less severe tear hyperosmolarity, defined as hyperosmolar eyes in the lower quartile (622.7 ± 5.8 μm, P < 0.0001). CCT showed a negative linear relationship with tear osmolarity for values above 316 mOsmol/L (R2 = 0.17, P = 0.01). Central corneal reflectivity was lower in hyperosmolar eyes than normo-osmolar eyes (45.1 ± 0.3 vs. 48.1 ± 0.6 pixels, P = 0.02); the greatest relative difference was in the anterior stroma, where corneal reflectivity was 4.7 ± 1.9% less in hyperosmolar eyes (P < 0.01). Peak reflectivity of the tear-epithelial interface was 4.8% ± 3.5% higher in the hyperosmolar group than the normo-osmolar tear group (P = 0.04).ConclusionIndividuals with significant tear hyperosmolarity and clinical signs of symptoms of DED show reduced CCT and altered corneal reflectivity.Translational RelevanceAnterior segment FD-OCT provides novel insight into corneal microstructural differences in individuals with DED.

The Relationship between Metabolic Syndrome, Its Components, and Dry Eye: A Cross-Sectional Study

ABSTRACTPurpose: The aim of this study was to evaluate tear osmolarity and tear film function and ocular surface changes in patients with metabolic syndrome.Methods: 108 eyes of 64 patients with metabolic syndrome (group 1) and 110 eyes of 55 healthy individuals (group 2) were included in this cross-sectional study. All participants were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire, Schirmer I test, tear film break-up time (TBUT), and tear osmolarity. Main outcome measures were Ocular Surface Disease Index (OSDI) questionnaire, Schirmer I test, tear film break-up time (TBUT), and tear osmolarity values.Results: Tear osmolarity values and OSDI scores were significantly higher in group 1 (314.4 ± 19.1 mOsm and 38.9 ± 1.1, respectively) compared with group 2 (295 ± 14.3 mOsm and 18.69 ± 17.2, respectively) (p = 0.01 for both). The Schirmer test values and TBUT in group 1 (10 ± 3.7 mm and 14.8 ± 3.6 sec, respectively) were significantly lower compared with group 2 (16.8 ± 2.6 mm and 18.1 ± 0.5 sec, respectively) (p < 0.001 for both). There was significant correlation between tear osmolarity versus waist circumference and fasting blood glucose in the study group (r = 0.364, p = 0.04; and r = 0.542, p ≤ 0.001, respectively).Conclusions: This study showed that metabolic syndrome can influence tear osmolarity and tear film function. Patients with metabolic syndrome showed tear hyperosmolarity and tear film dysfunction.

Autologous serum eye drops for dry eye.

Autologous serum eye drops for dry eye.

Hyperosmotic stress induces ATP release and changes in P2X7 receptor levels in human corneal and conjunctival epithelial cells.

Tear hyperosmolarity is a key event in dry eye. In this work, we analyzed whether hyperosmolar challenge induces ATP release on the ocular surface. Moreover, as extracellular ATP can activate P2X7 receptor, the changes in P2X7 protein levels and its involvement in pathological process triggered by hypertonic treatment were also examined. High-performance liquid chromatography analysis revealed that ATP levels significantly increased in human corneal and conjunctival epithelial cells exposed to hyperosmotic challenge as well as in dry eye patients as compared to control subjects. A significant reduction in cell viability was detected after hyperosmolar treatment, indicating that the rise in ATP release was mainly due to cell lysis/death. Additionally, vesicular nucleotide transporter was identified in both cell lines and their protein expression was upregulated in hypertonic media. P2X7 receptor truncated form together with the full-length form was identified in both cell lines, and experiments using specific antagonist and agonist for P2X7 indicated that this receptor did not mediate cell death induced by hyperosmolar stress. In conclusion, hyperosmotic stress induces ATP release. Extracellular ATP can activate P2X7 receptor leading to cytotoxicity in many cells/tissues; however, this does not occur in human corneal and conjunctival epithelial cells. In these cells, the presence of P2X7 receptor truncated form together with the full-length form hinders a P2X7 apoptotic behavior on the ocular surface.

Tear osmolarity and ocular surface parameters in patients with psoriasis.

The aim of this study was to evaluate tear osmolarity, tear film function, and ocular surface changes in patients with psoriasis. At a single center, 30 eyes of 30 patients with psoriasis (group 1) and 30 eyes of 30 healthy individuals (group 2) were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire, Schirmer I test, tear film break-up time (TBUT) test, scoring of ocular surface fluorescein staining using a modified Oxford scale, and tear osmolarity measurement. Tear osmolarity values, OSDI, and Oxford scale scores were significantly higher in group 1 (309.8 ± 9.4 mOsm, 38.9 ± 1.1, and 0.7 ± 1.1, respectively) than in group 2 (292.7 ± 7.7 mOsm, 4.2 ± 0.3, and 0.1 ± 0.3, respectively; p<0.01 for all). TBUT was significantly lower in group 1 (8.7 ± 3.6 s) than in group 2 (18.1 ± 2.8 s; p<0.001). No significant differences were detected in Schirmer I test values between the groups (16.2 ± 2.5 mm in group 1 and 16.6 ± 2.3 mm in group 2; p=0.629). The results of this study showed that psoriasis may influence tear osmolarity and tear film function. Patients with psoriasis showed tear hyperosmolarity and tear film dysfunction.

Hyperosmolarity and Benzalkonium Chloride Differently Stimulate Inflammatory Markers in Conjunctiva-Derived Epithelial Cells in vitro

Tear hyperosmolarity is known to cause ocular surface inflammation in dry eye syndrome. Benzalkonium chloride (BAK), an eyedrop preservative, is known to induce dry eye in long-term-treated patients. Analyzing the modulation of the proinflammatory potential of hyperosmolarity in the presence of BAK on the conjunctiva could give new insights into the effect of this preservative on the disease. In a hyperosmolar model on a conjunctiva-derived cell line, and in the presence of BAK, we evaluated key inflammatory markers [CCL2, IL-8, IL-6, macrophage migration inhibitory factor (MIF) and intercellular adhesion molecule (ICAM)-1] as well as the osmoprotectant element nuclear factor of activated T cells (NFAT)5 using ELISA, RT-qPCR or immunofluorescence staining. Hyperosmolarity highly stimulated CCL2 and NFAT5 in these cells. BAK alone only increased IL-6 expression. The stress-combined condition stimulated CCL2, NFAT5, MIF and IL-8 secretion. ICAM-1 was not modulated by any of the conditions tested. In this model, hyperosmolarity and BAK induced the release of different proinflammatory mediators, and, when combined, they lead to the release of additional inflammatory cytokines. This in vitro study highlights the importance of avoiding long-term ophthalmic treatments containing BAK, as tear film hyperosmolarity can be a result of its detergent action.

Visual acuity and quality of life in dry eye disease: Proceedings of the OCEAN group meeting

Dry eye disease (DED) results in tear film instability and hyperosmolarity, inflammation of the ocular surface and, ultimately, visual disturbance that can significantly impact a patient's quality of life. The effects on visual acuity result in difficulties with driving, reading and computer use and negatively impact psychological health. These effects also extend to the workplace, with a loss of productivity and quality of work causing substantial economic losses. The effects of DED and the impact on vision experienced by patients may not be given sufficient importance by ophthalmologists. Functional visual acuity (FVA) is a measure of visual acuity after sustained eye opening without blinking for at least 10 s and mimics the sustained visual acuity of daily life. Measuring dynamic FVA allows the detection of impaired visual function in patients with DED who may display normal conventional visual acuity. There are currently several tests and methods that can be used to measure dynamic visual function: the SSC-350 FVA measurement system, assessment of best-corrected visual acuity decay using the interblink visual acuity decay test, serial measurements of ocular and corneal higher order aberrations, and measurement of dynamic vision quality using the Optical Quality Analysis System. Although the equipment for these methods may be too large or unaffordable for use in clinical practice, FVA testing is an important assessment for DED.

Tear Osmolarity and Tear Film Parameters in Patients With Ocular Rosacea.

The aim of this study was to evaluate tear osmolarity and tear film parameters in patients with ocular rosacea. In a single center, 25 eyes of 25 patients with ocular rosacea (group 1), 25 eyes of 25 patients with rosacea without ocular involvement (group 2), and 20 eyes of 20 healthy individuals (group 3) were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire, Schirmer I test, tear film break-up time (TBUT), scoring of ocular surface fluorescein staining using modified Oxford scale, and tear osmolarity. Tear osmolarity values, OSDI and Oxford scale scores were significantly higher in group 1 than in groups 2 and 3 (P<0.001 for all). Schirmer I test and TBUT in group 1 were significantly lower than in groups 2 and 3 (P<0.001 for all). There were no significant differences in OSDI, Schirmer I test, TBUT, Oxford scores, or tear osmolarity between groups 2 and 3 (P=0.629, P=0.175, P=0.713, P=865, and P=0.388, respectively). This study showed that ocular rosacea is associated with tear hyperosmolarity and tear film dysfunction.

Tear Interferon-Gamma as a Biomarker for Evaporative Dry Eye Disease.

To assess whether tear hyperosmolarity, being diagnostic of dry eye disease (DED), is associated with specific alterations to the cytokine content of human tears that may provide a biomarker for DED. In this prospective, cross-sectional, clinical study, participants (n = 77) were recruited from a single clinical site and categorized into groups based upon tear osmolarity status (n = 62 hyperosmolar, n = 15 normo-osmolar). Comprehensive anterior eye clinical assessments were undertaken. Concentrations of seven cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, and TNF-α) in basal tears were assayed using multiplex cytometric bead array. The main outcome measure was difference in cytokine concentration between groups. Group comparisons were undertaken using 2-tailed t-tests. Cohen's effect size was calculated for each finding. Spearman correlations between cytokine concentrations, clinical symptoms, and clinical parameters of DED were calculated. Tear hyperosmolarity was specifically associated with increased tear IFN-γ levels (13.3 ± 2.0 vs. 4.4 ± 1.4 pg/mL, P = 0.03). Cohen's effect size was large (0.8) for changes to tear IFN-γ levels. Significant correlations were observed between IFN-γ concentration and each of: tear osmolarity (r = 0.34; P = 0.007), total ocular surface staining (r = 0.56, P < 0.0001), and Schirmer test score (r = -0.33, P = 0.003). Tear hyperosmolarity is specifically associated with higher levels of the proinflammatory cytokine IFN-γ, which correlate with key clinical parameters of DED. The calculated effect size (0.8) suggests that this assay has diagnostic power as a biomarker for evaporative DED.

Tear film assessments for the diagnosis of dry eye.

Dry eye disease (DED) is a complex, multifactorial condition that is challenging to diagnose and monitor clinically. To date, diagnosis has consisted largely of self-reported symptom questionnaires and a collection of clinical tests including vital dye staining, estimation of tear breakup time and Schirmer's testing, as no gold standard exists. As the dry eye field has made progress in understanding disease pathogenesis, new methods for assessment of this condition have been developed. DED is now known to be characterized by tear hyperosmolarity and ocular surface inflammation, and there are now commercially available devices that accurately and reliably measure tear osmolarity and matrix metalloproteinase 9, a marker of inflammation and tissue breakdown. In addition, there are a variety of imaging modalities that have shown promise in their ability to identify patients with DED by assessing tear film dimensions and tear film instability. There is a significant need for the development of tear film assessments for accurate diagnosis and monitoring of dry eye. There are a number of new devices and techniques that have shown promise in their ability help clinicians manage patients with DED.

Immunomodulation on the ocular surface: a review.

The increasing understanding of immune mechanisms changed our perception of the ocular surface, which is now considered a compartment of the common mucosal immune system. It offered the possibility to alter the physiological immune response on the ocular surface and effectively combat inflammation, which impairs stability of the tear film and causes tear hyperosmolarity, causing symptoms of dry eye disease. The paper provides an overview of ocular surface anatomy and physiology, explains the underlying mechanisms of dry eye disease and discusses novel and promising treatment modalities, such as cyclosporine A, biological therapies using autologous serum and various growth factors as well as experimental treatment methods which are currently being investigated.

Comment on "The Effects of Hemodialysis on Tear Osmolarity".

We congratulate Taskapili et al. for their study entitled “The Effects of Hemodialysis on Tear Osmolarity” [1]. The authors investigated the effects of hemodialysis (HD) on tear osmolarity (TO) and evaluated the correlation between blood biochemical tests and TO in patients with end stage renal disease (ESRD). In this study, they evaluated TO of patients with ESRD one minute before the beginning of HD and 30 minutes after the end of HD. The authors established that HD effectively decreases TO to normal values and corrects the volume and composition of the ocular fluid transiently. They observed tear hyperosmolarity before HD and a significant reduction to normal levels after HD. We have read the paper with great interest. We noticed that the authors did not mention the time of HD start in the day. It was reported that there was a diurnal variation of TO for normal subjects, which significantly changes upon awakening and remains relatively constant throughout most of the day [2]. In this study it was stated that the tear film was hypoosmotic upon awakening compared with baseline and TO changed quickest within the first 10 minutes and increased to baseline levels within the first 40 minutes [2]. TO decreased slowly thereafter until the 8-hour visit, followed by a relatively hyperosmotic trend toward the end of the day [2]. We think that detection of TO would be performed at the same time of the day regarding the duration of HD which may avoid the bias of the methodology.

Hyperosmolar Tears Induce Functional and Structural Alterations of Corneal Nerves: Electrophysiological and Anatomical Evidence Toward Neurotoxicity.

In an effort to elucidate possible neural mechanisms underlying diminished tearing in dry eye disease, this study sought to determine if hyperosmolar tears, a ubiquitous sign of dry eye disease, produce functional changes in corneal nerve responses to drying of the cornea and if these changes correlate with alterations in corneal nerve morphology. In vivo extracellular electrophysiological recordings were performed in rat trigeminal ganglion neurons that innervated the cornea before, and up to 3 hours after, the ocular application of continuous hyperosmolar tears or artificial tears. In corollary experiments, immunohistochemical staining was performed to compare corneal nerve morphology in control and in eyes treated with hyperosmolar solutions. Our previous studies identified a population of corneal afferents, dry-sensitive neurons that are strongly excited by corneal dessication ("dry response"), a response thought to trigger the lacrimation reflex. In the present study, we found that the dry responses of corneal dry-sensitive neurons were depressed or even completely abolished by hyperosmolar tears in a time- (30 minutes to 3 hours) and dose (450- to 1000-mOsm solutions)-dependent manner. Furthermore, eyes treated with hyperosmolar tears for 3 hours contained large numbers of morphologically abnormal (granular, fragmented, or prominently beaded) subbasal nerves that appeared to be undergoing degeneration. These results demonstrate that tear hyperosmolarity, considered to be a "core" mechanism of dry eye disease, significantly decreases physiological sensitivity and morphologic integrity of the corneal nerves important in tear production. These alterations might contribute to the diminished tearing seen clinically in dry eye patients.

Automated Tear Film Surface Quality Breakup Time as a Novel Clinical Marker for Tear Hyperosmolarity in Dry Eye Disease

To assess the diagnostic performance of a novel, automated, noninvasive measure of tear film stability derived from Placido disc videokeratography, the tear film surface quality breakup time (TFSQ-BUT), as a clinical marker for diagnosing dry eye disease (DED) relative to a standard of tear hyperosmolarity. This prospective, cross-sectional study involved 45 participants (28 DED, 17 controls). Symptoms (Ocular Surface Disease Index) and signs (tear osmolarity, TFSQ-BUT, tear breakup time measured with sodium fluorescein [NaFl-BUT], ocular surface staining and Schirmer test with topical anesthesia) of DED were assessed. Three measures of TFSQ-BUT and NaFl-BUT were taken per eye; "first," "average," and "shortest" BUT were analyzed separately. Optimal diagnostic cutoff values were determined using the Youden Index. The repeatability and agreement of the TFSQ-BUT was compared with two clinicians who manually assessed noninvasive BUT (CNI-BUT). Repeatability of methods was assessed using the geometric coefficient of variation (gCoV, %). Agreement between methods was considered with Bland-Altman analysis. Eyes with DED had significantly shorter TFSQ-BUTs than controls (P < 0.05). There was a significant, moderate correlation between both shortest and average TFSQ-BUT and NaFl-BUT (r = 0.35, P = 0.02 and r = 0.38, P = 0.01, respectively). The receiver-operator characteristic (ROC) curve for shortest TFSQ-BUT showed an area under the curve of 0.92 (P < 0.0001). Shortest TFSQ-BUT with a criterion of 12.1 seconds had a sensitivity of 82% and specificity of 94% for diagnosing DED against tear hyperosmolarity. Automated TFSQ-BUT showed less variability (gCoV = 9.4%, 95% confidence interval [CI]: 7.1%-14.0%) than CNI-BUT (gCoV = 27.0%, 95% CI: 19.62%-41.06%, P < 0.05). Automated TFSQ-BUT is a repeatable, noninvasive clinical marker with both high sensitivity and specificity for tear hyperosmolarity.

Novel role of PELI3 as a potential biomarker for Sjogren's syndrome related dry eyes

PurposeIn Sjogren's syndrome (SS) related dry eyes (SS‐KCS), reduced aqueous tear production and tear hyperosmolarity leads to inflammatory damage to the ocular surface. microRNAs (miR) are known to alter the expression of cytokines, which plays an important role in the pathogenesis and progression of SS. The aim of this study was to isolate miRs and mRNA from conjunctival epithelial cells (CEC) of patients with primary SS (pSS) to identify potential biomarkers that might aid diagnosis and future therapy in pSS.MethodsConfirmed SS‐KCS and healthy controls were recruited to this study. mRNA isolated from conjunctival impression cytology was sent for miR and mRNA microarray. Bioinformatic analysis was performed to identify predicted targets and comparison was made with the mRNA microarray data. Validation experiments were performed in HeLa cells following transfection with selected miR mimics and predicted genes were detected using qPCR.ResultsmiR and mRNA microarray found 32 differentially expressed novel miRs and 136 differentially expressed genes in pSS patients compared to healthy controls. Following bioinformatic analysis, novel miR‐A was chosen for further analysis. miR‐A was significantly increased in pSS (p = 0.0079) and bioinformatics suggested Pellino3 (PELI3), a negative regulator of inflammatory cytokines, as a predicted target. The mRNA microarray showed a decrease in PELI3 in pSS patients compared to healthy controls (p = 0.0731). Overexpression of miR‐A mimic in HeLa cells resulted in decreased expression of PELI3, suggesting that it is a direct target for miR‐A.ConclusionsWe have identified differentially expressed miRs and gene targets from CEC in pSS. PELI3, a potential target of novel miR‐A which is over expressed in pSS, is a negative regulator of cytokines that might have biomarker and therapeutic potential for pSS related dry eyes.

Novel role of PELI3 as a potential biomarker for Sjogren's syndrome related dry eyes

PurposeIn Sjogren's syndrome (SS) related dry eyes (SS‐KCS), reduced aqueous tear production and tear hyperosmolarity leads to inflammatory damage to the ocular surface. microRNAs (miR) are known to alter the expression of cytokines, which plays an important role in the pathogenesis and progression of SS. The aim of this study was to isolate miRs and mRNA from conjunctival epithelial cells (CEC) of patients with primary SS (pSS) to identify potential biomarkers that might aid diagnosis and future therapy in pSS.MethodsConfirmed SS‐KCS and healthy controls were recruited to this study. mRNA isolated from conjunctival impression cytology was sent for miR and mRNA microarray. Bioinformatic analysis was performed to identify predicted targets and comparison was made with the mRNA microarray data. Validation experiments were performed in HeLa cells following transfection with selected miR mimics and predicted genes were detected using qPCR.ResultsmiR and mRNA microarray found 32 differentially expressed novel miRs and 136 differentially expressed genes in pSS patients compared to healthy controls. Following bioinformatic analysis, novel miR‐A was chosen for further analysis. miR‐A was significantly increased in pSS (p = 0.0079) and bioinformatics suggested Pellino3 (PELI3), a negative regulator of inflammatory cytokines, as a predicted target. The mRNA microarray showed a decrease in PELI3 in pSS patients compared to healthy controls (p = 0.0731). Overexpression of miR‐A mimic in HeLa cells resulted in decreased expression of PELI3, suggesting that it is a direct target for miR‐A.ConclusionsWe have identified differentially expressed miRs and gene targets from CEC in pSS. PELI3, a potential target of novel miR‐A which is over expressed in pSS, is a negative regulator of cytokines that might have biomarker and therapeutic potential for pSS related dry eyes.

Global Metabonomic and Proteomic Analysis of Human Conjunctival Epithelial Cells (IOBA-NHC) in Response to Hyperosmotic Stress.

"Dry eye" is a multifactorial inflammatory disease affecting the ocular surface. Tear hyperosmolarity in dry eye contributes to inflammation and cell damage. Recent research efforts on dry eye have been directed toward biomarker discovery for diagnosis, response to treatment, and disease mechanisms. This study employed a spontaneously immortalized normal human conjunctival cell line, IOBA-NHC, as a model to investigate hyperosmotic stress-induced changes of metabolites and proteins. Global and targeted metabonomic analyses as well as proteomic analysis were performed on IOBA-NHC cells incubated in serum-free media at 280 (control), 380, and 480 mOsm for 24 h. Twenty-one metabolites and seventy-six iTRAQ-identified proteins showed significant changes under at least one hyperosmotic stress treatment as compared with controls. SWATH-based proteomic analysis further confirmed the involvement of inflammatory pathways such as prostaglandin 2 synthesis in IOBA-NHC cells under hyperosmotic stress. This study is the first to identify glycerophosphocholine synthesis and O-linked β-N-acetylglucosamine glycosylation as key activated pathways in ocular surface cells under hyperosmotic stress. These findings extend the current knowledge in metabolite markers of dry eye and provide potential therapeutic targets for its treatment.

Diagnostic value of tear hyperosmolarity in dry eye

Background Tear hyperosmosis is considered to be one of the core mechanisms of dry eye.The measurement of tear osmolarity is important in the clinical diagnosis of dry eye.However, relevant study is lack in Chinese population. Objective The aim was to investigate the relation of tear osmolarity and pathogenesis of dry eye and evaluate the diagnosis value of tear hyperosmosis in dry eye. Methods Sixty-one consecutive dry eye patients were enrolled in Affiliated Eye Hospital of Wenzhou Medical University from May to August in 2011, including 30 mild and moderate dry eyes and 31 severe dry eyes, and 30 normal volunteers with matched age and gender were collected simultaneously under the informed consent.The visual acuity, Ocular Surface Disease Index (OSDI) questionnaire, osmotic pressure of tear, tear film breakup time (TFBUT), corneal fluorescein staining, conjunctival lissamine green staining, ShirmerⅠtest (SⅠt) without anesthesia and meibomian function were examined in turn in the subjects, and lateral eyes with higher tear osmotic pressure were analyzed.The differences in above indexes among the different groups were statistically compared, and the correlations between the osmotic pressure of tear and clinical parameters were assessed. Results The osmotic pressure of tear was (326.46±22.66) mOsm/L in the dry eye group, which was significantly higher than (296.60±10.81) mOsm/L in the normal control group (P 0.05). Conclusions Tears osmotic pressure might be a useful indicator for the diagnosis of dry eye and assessment of severity.A combined application of tear osmolarity measurement with other relevant indexes can improve the diagnostic value. Key words: Dry eye/diagnosis; Tears; Osmolar concentration; Diagnostic techniques, ophthalmological/instrumentation