Corticosteroid and doxycycline suppress MMP-9 and inflammatory cytokine expression, MAPK activation in the corneal epithelium in experimental dry eye

Inhibitory effects of doxycycline on the onset and progression of abdominal aortic aneurysm and its related mechanisms

The objective of this study was to investigate whether doxycycline (DOX) given at different doses and via different administration routes had protective or therapeutic effects on abdominal aortic aneurysm (AAA) induced by elastase in mice. Moreover, the anti-AAA mechanism of DOX was studied in TNF-α-stimulated vascular smooth muscle cell (VSMC) in vitro. For in vivo study, either daily administration of 30mg/kg of DOX by gavage or intraperitoneal injection of 15mg/kg DOX every other day for 14 days significantly prevented the development of AAA at its early stage. Further study showed that intraperitoneal injection of 15mg/kg DOX every other day for 7 times in total could also cure the established AAA. In vitro study showed that treating VSMCs with TNF-α together with DOX remarkably inhibited the expressions and activities of MMPs (MMP-2 and MMP-9), significantly suppressed the activation of protein kinase B (AKT) signaling pathway and mitogen-activated protein kinases (MAPKs) signal proteins, including extracellular signal-regulated kinase (ERK), c-Jun amino-terminal kinases (JNK) and p38, and downregulated mRNA levels of interleukin-6 (IL-6) and monocyte chemotactic protein 1 (MCP-1), and significantly upregulated mRNA levels of transforming growth factor beta (TGF-β), heme oxygenase 1 (HO-1) and superoxide dismutase 1 (SOD-1), indicating that DOX inhibits activities of MMPs through reducing oxidative stress, suppressing MAPKs and AKT signaling pathways and ameliorating inflammation in VSMCs, and therefore, exerts preventive as well as therapeutic effects on AAA.

Comparison of 0.3% Hypotonic and Isotonic Sodium Hyaluronate Eye Drops in the Treatment of Experimental Dry Eye

PURPOSE

To compare the efficacy of 0.3% hypotonic and isotonic sodium hyaluronate (SH) eye drops in the treatment of experimental dry eye.

METHODS

Experimental dry eye was established in female C57BL/6 mice by subcutaneous scopolamine injection and an air draft. The mice were divided into three groups (n = 15): control, preservative-free 0.3% isotonic SH, and preservative-free 0.3% hypotonic SH. The tear volume, tear film break-up time, and corneal fluorescein staining scores were measured 5 and 10 days after treatment. After conjunctival tissues were excised at 10 days, the levels of interleukin (IL)-6, IL-17, interferon (IFN)-γ, and IFN-γ inducible protein-10 were determined using the multiplex immunobead assay. In addition, PAS staining and flow cytometry were performed to evaluate the counts of conjunctival goblet cells and CD4+ IFN-γ+ T cells.

RESULTS

Mice treated with 0.3% hypotonic SH showed a significant decrease in corneal staining scores (P = 0.04) and the levels of IL-6 (16.7 ± 1.4 pg/mL, P = 0.02) and IFN-γ (46.5 ± 11.5 pg/mL, P = 0.02) compared to mice treated with 0.3% isotonic SH (IL-6; 32.5 ± 8.8 pg/mL, IFN-γ; 92.0 ± 16.0 pg/mL) at day 10. Although no significant difference in CD4+ IFN-γ+ T cell numbers was observed, goblet cell counts were higher in the hyopotonic SH group than in the isotonic SH group (P = 0.02).

CONCLUSIONS

When compared to 0.3% isotonic SH eye drops, 0.3% hypotonic SH eye drops can be more effective by improving corneal staining scores, decreasing inflammatory molecules, and increasing goblet cell counts for experimental dry eye. These data suggest that hypotonic artificial tears may be useful as an adjunctive treatment for inflammatory dry eye.

Effects of silk fibroin in murine dry eye

The study aimed to investigate the effects of silk fibroin in a mouse model of dry eye. The experimental dry eye mouse model was developed using more than twelve-weeks-old NOD.B10.H2^b mice exposing them to 30–40% ambient humidity and injecting them with scopolamine hydrobromide for 10 days. Tear production and corneal irregularity score were measured by the instillation of phosphate buffered saline or silk fibroin. Corneal detachment and conjunctival goblet cell density were observed by hematoxylin and eosin or periodic acid Schiff staining in the cornea or conjunctiva. The expression of inflammatory markers was detected by immunohistochemistry in the lacrimal gland. The silk group tear production was increased, and corneal smoothness was improved. The corneal epithelial cells and conjunctival goblet cells were recovered in the silk groups. The expression of inflammatory factors was inhibited in the lacrimal gland of the silk group. These results show that silk fibroin improved the cornea, conjunctiva, and lacrimal gland in the mouse model of dry eye. These findings suggest that silk fibroin has anti-inflammatory effects in the experimental models of dry eye.

Dysfunctional tear syndrome: dry eye disease and associated tear film disorders - new strategies for diagnosis and treatment

Dysfunctional tear syndrome (DTS) is a common and complex condition affecting the ocular surface. The health and normal functioning of the ocular surface is dependent on a stable and sufficient tear film. Clinician awareness of conditions affecting the ocular surface has increased in recent years because of expanded research and the publication of diagnosis and treatment guidelines pertaining to disorders resulting in DTS, including the Delphi panel treatment recommendations for DTS (2006), the International Dry Eye Workshop (DEWS) (2007), the Meibomian Gland Dysfunction (MGD) Workshop (2011), and the updated Preferred Practice Pattern guidelines from the American Academy of Ophthalmology pertaining to dry eye and blepharitis (2013). Since the publication of the existing guidelines, new diagnostic techniques and treatment options that provide an opportunity for better management of patients have become available. Clinicians are now able to access a wealth of information that can help them obtain a differential diagnosis and treatment approach for patients presenting with DTS. This review provides a practical and directed approach to the diagnosis and treatment of patients with DTS, emphasizing treatment that is tailored to the specific disease subtype as well as the severity of the condition.

Effects of retinoic acid receptor-γ on the Aspergillus fumigatus induced innate immunity response in human corneal epithelial cells

AIM

To explore the effects of retinoic acid receptor-γ (RARγ) on innate immune responses against Aspergillus fumigatus (A. fumigatus) in cultured human corneal epithelial cells (HCECs).

METHODS

The HCECs were stimulated with A. fumigatus hyphae for 0, 2, 4, 8, 12 and 16h. RARγ mRNA and protein levels were tested by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Then HCECs were pretreated with or without BMS961 (RARγ agonist, 1 µg/mL). The mRNA and protein expression of Dectin-1 and the downstream cytokines (TNF-α and IL-6) were determined by qRT-PCR, Western blot and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The expression of RARγ was upregulated after stimulation with A. fumigatus. RARγ mRNA began to rise at 4h and peaked at 8h (P<0.001). The protein of RARγ reached to the peak at 16h (P<0.001). Pretreated with BMS961 before A. fumigatus hyphae stimulation, expression of Dectin-1, TNF-α and IL-6 decreased dramatically at mRNA and protein levels.

CONCLUSION

HCECs can express RARγ and A. fumigatus hyphae infection can increase RARγ expression. BMS961 can inhibit the expression of Dectin-1 and pro-inflammatory cytokines, and play an anti-inflammatory role in innate immune responses against A. fumigatus.

Doxycycline Inhibits IL-17-Stimulated MMP-9 Expression by Downregulating ERK1/2 Activation: Implications in Myogenic Differentiation

Interleukin 17 (IL-17) is a cytokine with pleiotropic effects associated with several inflammatory diseases. Although elevated levels of IL-17 have been described in inflammatory myopathies, its role in muscle remodeling and regeneration is still unknown. Excessive extracellular matrix degradation in skeletal muscle is an important pathological consequence of many diseases involving muscle wasting. In this study, the role of IL-17 on the expression of matrix metalloproteinase- (MMP-) 9 in myoblast cells was investigated. The expression of MMP-9 after IL-17 treatment was analyzed in mouse myoblasts C2C12 cell line. The increase in MMP-9 production by IL-17 was concomitant with its capacity to inhibit myogenic differentiation of C2C12 cells. Doxycycline (Doxy) treatment protected the myogenic capacity of myoblasts from IL-17 inhibition and, moreover, increased myotubes hypertrophy. Doxy blocked the capacity of IL-17 to stimulate MMP-9 production by regulating IL-17-induced ERK1/2 MAPK activation. Our results imply that MMP-9 mediates IL-17's capacity to inhibit myoblast differentiation during inflammatory diseases and indicate that Doxy can modulate myoblast response to inflammatory induction by IL-17.

Presence or absence of ocular surface inflammation directs clinical and therapeutic management of dry eye

Background

The presence of clinically significant inflammation has been confirmed in the tears of 40%–65% of patients with symptoms of dry eye. Ocular surface inflammation may lead to tear film instability, epithelial cell irregularities, and permeability, resulting in chronic symptomatic pain and fluctuating vision as well as negative surgical outcomes.

Patients and methods

A retrospective single center medical chart review of 100 patients was conducted. All patients were tested with the InflammaDry test to determine if patients exhibited elevated levels of matrix metalloproteinase 9 (MMP-9). InflammaDry-positive patients were started on a combination of cyclosporine 0.05% twice daily, 2,000–4,000 mg oral omega-3 fatty acids, and frequent artificial tear replacement. InflammaDry-negative patients were started on 2,000–4,000 mg of oral omega-3 fatty acids and frequent artificial tear replacement. Each patient was retested at ~90 days. A symptom questionnaire was performed at the initial visit and at 90 days.

Results

60% of the patients with dry eye symptoms tested positive for elevated MMP-9 at the initial visit. 78% of all patients returned for follow-up at ~90 days including 80% (48/60) of the previously InflammaDry-positive patients and 75% (30/40) of the previously InflammaDry-negative patients. A follow-up symptom questionnaire reported at least 75% symptomatic improvement in 65% (31/48) of the originally InflammaDry-positive patients and in 70% (21/30) of the initially InflammaDry-negative patients. Symptomatic improvement of at least 50% was reported in 85% (41/48) of previously InflammaDry-positive patients and 86% (26/30) of previously InflammaDry-negative patients. Following treatment, 54% (26/48) of previously InflammaDry-positive patients converted to a negative InflammaDry result.

Conclusion

Identifying which symptomatic dry eye patients have underlying inflammation may predict patient responses to treatment and influence clinical management strategies.

Topical Application of Apricot Kernel Extract Improves Dry Eye Symptoms in a Unilateral Exorbital Lacrimal Gland Excision Mouse

The purpose of this study was to investigate the therapeutic effects of topical application of apricot kernel extract (AKE) in a unilateral exorbital lacrimal gland excision mouse model of experimental dry eye. Dry eye was induced by surgical removal of the lacrimal gland. Eye drops containing 0.5 or 1 mg/mL AKE were administered twice a day from day 3 to day 7 after surgery. Tear fluid volume and corneal irregularity scores were determined. In addition, we examined the immunohistochemical expression level of Muc4. The topical administration of AKE dose-dependently improved all clinical dry eye symptoms by promoting the secretion of tear fluid and mucin. Thus, the results of this study indicate that AKE may be an efficacious topical agent for treating dry eye disease.

Pollen/TLR4 Innate Immunity Signaling Initiates IL-33/ST2/Th2 Pathways in Allergic Inflammation

Innate immunity has been extended to respond environmental pathogen other than microbial components. Here we explore a novel pollen/TLR4 innate immunity in allergic inflammation. In experimental allergic conjunctivitis induced by short ragweed (SRW) pollen, typical allergic signs, stimulated IL-33/ST2 signaling and overproduced Th2 cytokine were observed in ocular surface, cervical lymph nodes and isolated CD4⁺ T cells of BALB/c mice. These clinical, cellular and molecular changes were significantly reduced/eliminated in TLR4 deficient (Tlr4-d) or MyD88 knockout (MyD88^−/−) mice. Aqueous SRW extract (SRWe) directly stimulated IL-33 mRNA and protein expression by corneal epithelium and conjunctiva in wild type, but not in Tlr4-d or MyD88^−/− mice with topical challenge. Furthermore, SRWe-stimulated IL-33 production was blocked by TLR4 antibody and NF-kB inhibitor in mouse and human corneal epithelial cells. These findings for the first time uncovered a novel mechanism by which SRW pollen initiates TLR4-dependent IL-33/ST2 signaling that triggers Th2-dominant allergic inflammation.

Matrix Metalloproteinase 9 Testing in Dry Eye Disease Using a Commercially Available Point-of-Care Immunoassay

PURPOSE

To measure matrix metalloproteinase 9 (MMP-9) in the tear film of patients with dry eye disease (DED) compared with controls and to correlate clinical findings.

DESIGN

In a prospective study, 101 patients and controls underwent MMP-9 testing of the tear film. Thereafter, they were evaluated for symptoms and signs of DED.

PARTICIPANTS

Included patients were those who showed 3 of the following 4 dry eye criteria: ocular surface disease index (OSDI) score of more than 12, tear film break-up time (TBUT) of 10 seconds or less, Schirmer test results without anesthesia of less than 10 mm/5 minutes, and corneal staining results of 1 or more. Fifty-four healthy eyes and 47 eyes fulfilling diagnostic criteria for DED of various levels of severity were included in this study.

METHODS

The tear film was analyzed for MMP-9 by a commercially available test (InflammaDry; Rapid Pathogen Screening, Inc, Sarasota, FL) detecting MMP-9 levels of more than 40 ng/ml. Symptoms and signs of DED were evaluated using the OSDI questionnaire, TBUT, conjunctival and corneal staining, Schirmer test results without anesthesia, and meibomian gland examination. These findings were correlated to results of the MMP-9 test in tears.

MAIN OUTCOME MEASURES

Positive MMP-9 results in tears.

RESULTS

In 19 of 47 patients confirmed with dry eye (40.4%) and in 3 of 54 controls (5.6%), the MMP-9 results were positive. This difference was statistically significant (P < 0.001). Thus, the MMP-9 results indicated a clinically significant inflammation in 40% of dry eye patients. Positive results correlated well with subjective symptoms of DED evaluated by OSDI (P = 0.001), TBUT of less than 5 seconds (P < 0.013), Schirmer test results (P < 0.001), conjunctival staining (P < 0.001), and corneal staining (P = 0.007). Moreover, MMP-9 results correlated with the number of obstructed meibomian ducts (P = 0.005) and a pathologic meibomian gland secretion (P = 0.001). The MMP-9 results were increased significantly in women (P < 0.001) and in patients with autoimmune disease (P = 0.005), especially Sjögren's syndrome (P = 0.001) and thyroid disease (P = 0.012).

CONCLUSIONS

Matrix metalloproteinase 9 testing in DED is a valuable new diagnostic tool. It correlated well with other dry eye tests and identified the presence of ocular surface inflammation in 40% of confirmed dry eye patients. It may be especially helpful to identify patients with ocular surface inflammation and autoimmune disease and may facilitate the decision to institute anti-inflammatory treatment in these patients.

Efficacy of 0.01% dexamethasone solution in comprehensive therapy of dry eye disease

Introduction. The officinal dosage of dexamethasone solution (0.1%) has a marked localized antiinflammatory effect. But the widespread use of this dose in the management of dry eye diseases is limited by the risk of damage to the cornea. Therefore, the authors developed a solution containing 0.01% dexamethasone phosphate in combination with 6% polyvinylpyrolidone and 1.5%–5.5% dextrose [3].  Aim. To study the effects of this novel anti-inflammatory solution on corneal inflammatory processes. Materials and methods. This study included a cohort of 25 patients (50 eyes) with corneal–conjunctival xerosis. Lower tear meniscus index, precorneal tear film production, stability and osmolarity, and the degree of staining of the ocular surface epithelium with vital solutions were assessed prior to the treatment and on day 28 of the study. The presence of the cytokines IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-17A, IL-1Ra, TNF-α, INF-α, and INF-γ in patients’ tear fluid and blood plasma was quantified using ELISA.  All patients were asked to complete a questionnaire to evaluate subjective signs of xerosis of the ocular surface. Results. Statistically significant increases in tear meniscus index, precorneal tear film stability, and main and total tear production, with a significant decrease in tear film osmolarity were observed by day 28 of the study. In addition, positive changes in objective parameters relating to the ocular surface epithelium were further confirmed by the patients’ evaluations of their quality of life. Furthermore, the degree of staining of the ocular surface epithelium with vital solutions also decreased. Conclusions. The results of the study demonstrate the high level of effectiveness of the developed medication as a treatment for dry eye diseases of various etiologies.

Comparison of the Efficacy of Fluorometholone With and Without Benzalkonium Chloride in Ocular Surface Disease

PURPOSE

The purpose of this study was to compare the cytotoxicity and antiinflammatory effect of preserved and unpreserved 0.1% fluorometholone (FML).

METHODS

Drug-induced morphological changes and cytotoxicity were examined in human corneal epithelial cells. Dry eye was induced in mice by treatment with 0.2% benzalkonium chloride (BAC) for the first 2 weeks, and then, the eyes (4 groups; Normal saline, BAC, preserved FML, and unpreserved FML) were treated thrice daily with each formulation for the next 2 weeks. Corneal tissues were embedded in paraffin and stained with hematoxylin and eosin for histopathological examination. Immunofluorescence staining was performed for tumor necrosis factor-α, interleukin-6, and human leukocyte antigen-DR. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay was performed to evaluate drug-induced cytotoxicity.

RESULTS

BAC and preserved FML caused cell shrinkage and detachment from the plate in a dose-dependent manner, and cell viability decreased significantly. However, cytotoxicity was reduced on treatment with unpreserved FML. Hematoxylin-eosin staining revealed surface desquamation, irregular surface, loss of cell borders, and stromal shrinkage in the group treated with BAC. On BAC exposure, tumor necrosis factor-α, interleukin-6, and human leukocyte antigen-DR were strongly detected, and cytotoxicity was markedly increased, as evidenced by a positive result in the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Ocular surface damage and inflammation were slightly reduced on treatment with preserved FML. In comparison, unpreserved FML did not induce morphological changes; moreover, decreased cell cytotoxicity and ocular surface inflammation were observed.

CONCLUSIONS

The cytotoxicity of antiinflammatory eye drops evaluated in this study was induced by the preservative BAC. Accordingly, unpreserved FML is more effective than preserved eye drops in decreasing ocular inflammation.

Expression of TSLP and Downstream Molecules IL-4, IL-5, and IL-13 on the Eye Surface of Patients with Various Types of Allergic Conjunctivitis

Background. The pathogenesis of allergic conjunctivitis has not been clearly established. Moreover, previous studies fail to consider human models of allergic conjunctivitis. This study investigated the expression of thymic stromal lymphopoiet in TSLP and its downstream molecules in conjunctival scrappings and tear. Methods. This cross-sectional study compares patients with vernal keratoconjunctivitis (VKC), seasonal allergic conjunctivitis (SAC), and perennial allergic conjunctivitis (PAC) with normal controls. There are 80 people recorded in Shanxi Eye Hospital. Increasingly, 20 are with VKC, 20 are with SAC, 20 are with PAC, and the remaining 20 are normal controls. Conjunctiva were harvested for total RNA extraction and gene expression by real-time polymerase chain reaction. Epithelial cells were collected to make pathological sections for immunohistochemical staining. Human tears were evaluated by Luminex microbead assay. A P value less than 0.05 from Dunnett's post hoc test in SPSS means a statistical significant distinction. Results. Positive expression in conjunctival cells of patients with allergic conjunctivitis. The expression of TSLP and IL-4, IL-5, and IL-13 mRNA shows a statistically significant difference (P < 0.05). TSLP and IL-4, IL-5, and IL-13 concentrations show a statistically significant difference (P < 0.01). Conclusions. This study suggests that TSLP and downstream molecules are expressed in patients with various types of allergic conjunctivitis.

Inhaled corticosteroids do not reduce initial high activity of matrix metalloproteinase (MMP)-9 in exhaled breath condensates of children with asthma exacerbation: a proof of concept study

Inhaled corticosteroids (ICS) are the key component of asthma treatment. However, it is unclear whether they could control the activity and level of matrix metalloproteinase (MMP)-9, which is an important factor in asthma-associated inflammation and airway remodeling. Therefore, the aim of this proof of concept study was to analyze the influence of increased doses of ICS on MMP-9 in exhaled breath condensates (EBC) of patients with allergic asthma exacerbation. Apart from MMP-9, the assessment concerned selected inflammation markers – exhaled nitric oxide (eNO) and cytokines (IL-8 and TNF).

The study involved a small group (n = 4) of individuals with asthma exacerbation. The intervention concerned increased doses of ICS with β-mimetics for 4 weeks. In addition to clinical evaluation, eNO measurements and EBC collections were done before and after 4 weeks of intense ICS treatment. The biochemical assessment of EBC concerned MMP-9, IL-8 and TNF. The data were compared to results of healthy controls (n = 6).

The initial levels of eNO, MMP-9 and TNF in EBC were higher in the asthma group than in controls. In all subjects IL-8 levels were below the detection limit. After 4 weeks of ICS treatment in all patients we observed improvement of clinical and laboratory parameters. Interestingly, despite reduction of eNO and TNF, the activity of MMP-9/EBC remained on the initial level.

Practical relevance of our results is limited by a small group. Nevertheless, our data suggest that ICS, although sufficient to control symptoms and inflammatory markers, may be ineffective to reduce MMP-9/EBC activity in asthma exacerbation and, possibly, airway remodeling.

Relationship Between Dynamic Changes in Expression of IL-17/IL-23 in Lacrimal Gland and Ocular Surface Lesions in Ovariectomized Mice

PURPOSE

An ovariectomized mouse model was constructed to observe the dynamic effects of hormone changes on the expression of interleukin (IL)-17A and IL-23 in the lacrimal glands.

METHODS

The ovariectomized mouse model was constructed by bilateral ovary removal. The concentrations of serum estradiol and testosterone in mouse cardiac blood were detected by radioimmunoassay. Mice in both groups underwent the phenol red cotton thread test and corneal fluorescein staining to assess the ocular surface, whereas Th17 cells in blood and spleen were detected by flow cytometry. IL-17A and IL-23 expression in the lacrimal glands was detected by immunohistochemistry, enzyme-linked immunosorbent assay, and real-time fluorescence quantitative polymerase chain reaction.

RESULTS

Serum estradiol and testosterone levels were significantly lower in the ovariectomized group compared with those in the control group. There was lymphocytic infiltration in the lacrimal gland of the ovariectomized group mice. At 6 months after the surgery, aqueous tear production was significantly lower, and statistically significant corneal fluorescein staining was found in the ovariectomized group, compared with that in the control group. In the ovariectomized group, IL-17A and the IL-23 expression in the lacrimal glands and the Th17 expression in the blood and spleen were significantly higher than in the control group.

CONCLUSION

The hormone levels are significantly reduced and lymphocytic infiltration in the lacrimal gland in ovariectomized mice, whereas the frequency of Th17 cells in the blood and spleen and IL-17A and IL-23 expression in the lacrimal glands are increased, leading to reduced tear production and positive fluorescein staining in the cornea.

Irritable bowel syndrome might be associated with dry eye disease

Background

A possible association between dry eye disease (DED) and irritable bowel syndrome (IBS) has been hypothesized based on the fact that they both share an inflammatory pathogenesis.

Methods

Ninety-five patients with IBS and 276 healthy controls were enrolled in the study. All patients answered a questionnaire regarding DED symptoms and had a complete ophthalmic examination. DED signs were evaluated using Schirmer’s 1 and tear break-up time (tBUT) tests in both groups.

Results

Female IBS participants presented significantly lower Schirmer’s test and tBUT (P=0.002 and P<0.001 respectively) than controls. Both diagnostic tests in male IBS patients were also significantly lower than in controls (P<0.001). 72% of IBS patients gave at least 3 positive answers to the questionnaire compared with 42% of the control group (P<0.01).

Conclusion

Our results suggest a correlation between IBS and DED. DED symptoms can cause further complications in patients with IBS, and should be considered in their management. However, further research is needed to establish a possible pathophysiologic association.

The influence of rigid gas permeable lens wear on the concentrations of dinucleotides in tears and the effect on dry eye signs and symptoms in keratoconus

PURPOSE

To evaluate the signs and symptoms of dry eye and dinucleotide secretion in tears of keratoconus patients (KC) and the potential effect of rigid gas permeable (RGP) contact lens wear.

METHODS

Twenty-three KC patients and forty control subjects were enrolled in this study. Signs of dry eye including tear volume, tear stability and corneal staining along with symptoms were assessed using the McMonnies questionnaire. Tears were collected using Schirmer strips, and dinucleotide concentrations in collected tears measured using high pressure liquid chromatography. Values obtained in KC and controls were compared. The effect of contact lens wear in KC was also assessed.

RESULTS

KC eyes showed a significantly lower tear volume compared to controls, shorter tear break up time (TBUT), higher corneal staining and higher McMonnies dry eye questionnaire scores (p<0.05). When compared with non-wearers, KC contact lens wearers showed significantly higher symptoms, lower Schirmer and TBUT values (p<0.05). Concentration of Ap4A (0.695±0.304μM vs. 0.185±0.178μM) and Ap5A (0.132±0.128μM vs. 0.045±0.036μM) were higher in KC compared to controls (p<0.001) and only Ap4A was statistically higher in RGP wearers compared to non-wearers (0.794±0.478μM vs. 0.417±0.313μM) (p<0.05).

CONCLUSION

Signs and symptoms of dry eye as well as concentrations of Ap4A and Ap5A were markedly increased in KC patients compared to controls. Moreover, Ap4A and symptoms of dry eye were statistically higher in RGP wearers compared to non-wearers. This seems to indicate that factors such as RGP contact lens wear might exacerbate the clinical condition of dry eye.

Assessment of conjunctival microvilli abnormality by micro-Raman analysis - by G. Rusciano et al

Conjunctival microvilli are microscopic cellular membrane protrusions on apical epithelial cells, which increase the surface area available for tear adherence. Pathological alterations of microvilli structure affect the tear film stability and, conversely, dysfunctions of tear film composition can lead to a suffering epithelium (dry-eye syndrome). In this work we propose the use of micro-Raman analysis to reveal conjunctival microvilli abnormalities. Samples were obtained by impression cytology from patients by different stage of dry-eye syndrome. Our experimental outcomes demonstrate that Raman analysis, combined with the use of Principal Component Analysis, is able to detect different stages of microvilli reduction. Globally, these results hold promise for the use of Raman analysis for an objective, effective, non-invasive and potentially also in-vivo analysis of the conjunctiva in all the cases of microvilli-related ocular pathologies.

Clusterin in the eye: An old dog with new tricks at the ocular surface

The multifunctional protein clusterin (CLU) was first described in 1983 as a secreted glycoprotein present in ram rete testis fluid that enhanced aggregation ('clustering') of a variety of cells in vitro. It was also independently discovered in a number of other systems. By the early 1990s, CLU was known under many names and its expression had been demonstrated throughout the body, including in the eye. Its homeostatic activities in proteostasis, cytoprotection, and anti-inflammation have been well documented, however its roles in health and disease are still not well understood. CLU is prominent at fluid-tissue interfaces, and in 1996 it was demonstrated to be the most highly expressed transcript in the human cornea, the protein product being localized to the apical layers of the mucosal epithelia of the cornea and conjunctiva. CLU protein is also present in human tears. Using a preclinical mouse model for desiccating stress that mimics human dry eye disease, the authors recently demonstrated that CLU prevents and ameliorates ocular surface barrier disruption by a remarkable sealing mechanism dependent on attainment of a critical all-or-none concentration in the tears. When the CLU level drops below the critical all-or-none threshold, the barrier becomes vulnerable to desiccating stress. CLU binds selectively to the ocular surface subjected to desiccating stress in vivo, and in vitro to LGALS3 (galectin-3), a key barrier component. Positioned in this way, CLU not only physically seals the ocular surface barrier, but it also protects the barrier cells and prevents further damage to barrier structure. CLU depletion from the ocular surface epithelia is seen in a variety of inflammatory conditions in humans and mice that lead to squamous metaplasia and a keratinized epithelium. This suggests that CLU might have a specific role in maintaining mucosal epithelial differentiation, an idea that can now be tested using the mouse model for desiccating stress. Most excitingly, the new findings suggest that CLU could serve as a novel biotherapeutic for dry eye disease.

Altered Mucosal Microbiome Diversity and Disease Severity in Sjögren Syndrome

There is mounting evidence that the microbiome has potent immunoregulatory functions. We assessed the effects of intestinal dysbiosis in a model of Sjögren syndrome (SS) by subjecting mice to desiccating stress (DS) and antibiotics (ABX). We characterized the conjunctival, tongue and fecal microbiome profiles of patients with SS. Severity of ocular surface and systemic disease was graded. 16S ribosomal RNA gene sequencing characterized the microbiota. ABX + DS mice had a significantly worse dry eye phenotype compared to controls, a decrease in Clostridium and an increase in Enterobacter, Escherichia/Shigella, and Pseudomonas in stool after ABX + DS for 10 days. Goblet cell density was significantly lower in ABX treated groups compared to controls. Stool from SS subjects had greater relative abundances of Pseudobutyrivibrio, Escherichia/Shigella, Blautia, and Streptococcus, while relative abundance of Bacteroides, Parabacteroides, Faecalibacterium, and Prevotella was reduced compared to controls. The severity of SS ocular and systemic disease was inversely correlated with microbial diversity. These findings suggest that SS is marked by a dysbiotic intestinal microbiome driven by low relative abundance of commensal bacteria and high relative abundance of potentially pathogenic genera that is associated with worse ocular mucosal disease in a mouse model of SS and in SS patients.

Mechanisms and management of dry eye in cataract surgery patients

PURPOSE OF REVIEW

To provide a summary of the mechanisms that may cause dry eye after cataract surgery and discuss available and upcoming treatment modalities.

RECENT FINDINGS

Development or worsening of dry eye symptoms after cataract surgery is multifactorial with corneal nerve transection, inflammation, goblet cell loss, and meibomian gland dysfunction commonly cited as underlying disorders. With increasing awareness of the prevalence of dry eye disease, current surgical techniques are being analyzed for their contribution to the issue. Although many classic interventions, such as artificial tears and anti-inflammatory drops, remain first-line treatment options, they may not adequately address abnormalities of the tear film. The trend has been to create new drugs and technologies that target meibomian gland deficiencies and restore goblet cell numbers.

SUMMARY

Therapy for postoperative dry eye symptoms should be determined based on symptom severity and which underlying cause is most prominent at a given time. Patients with high-level risk factors for dry eye should be evaluated preoperatively to determine whether they have preexisting dry eye disease or if they are susceptible to developing disease after surgery.

Co-administration of deflazacort and doxycycline: a potential pharmacotherapy for Duchenne muscular dystrophy

The standard therapy used in the treatment of Duchenne muscle dystrophy (DMD) is corticoids, such as deflazacort and prednisone. However, they have limited therapeutic value, and their combination with drugs already in use to treat other human diseases could potentially increase corticoid outcomes in DMD. In the present study, we evaluated whether a combined therapy of the corticoid deflazacort with doxycycline could result in greater improvement in mdx dystrophy than deflazacort alone. Deflazacort alone or deflazacort/doxycycline were administered for 36 days (starting on postnatal day 0) in drinking water. Histopathological, biochemical (creatine kinase), functional (forelimb muscle grip strength and fatigue) parameters and inflammatory markers (MMP-9, TNF-α, NF-kB) were evaluated in biceps brachii and diaphragm muscles of the mdx mice. The combined therapy was superior in improving the dystrophic phenotype compared to monotherapy. The primary results were observed in attenuating muscle fatigue, decreasing muscle total calcium and inflammatory markers and increasing β-dystroglycan, a main component of the dystrophin-protein complex. Furthermore, the combined therapy was effective in preventing the loss of body mass observed with deflazacort alone at this very early stage of therapy. The present study offers preclinical data to support further studies with deflazacort/doxycycline combined therapy in DMD clinical trials.

Sjögren syndrome: what and where are we looking for?

PURPOSE OF REVIEW

Sjögren's syndrome affects exocrine glands leading to a dry mouth and dry eyes. Dry eye manifestations can precede the diagnosis of Sjögren's syndrome by many years. Innumerous spontaneous and inducible Sjögren's syndrome models have been used to study the pathogenesis of Sjögren's syndrome. This review focuses on recent human data, ocular and extraglandular manifestations of animal models, what is known, what is still unknown and how we need to look, and their correlation correspondence to human disease.

RECENT FINDINGS

Hallmarks of dry eye in Sjögren's syndrome include increased corneal staining, goblet cell loss and low tear volume. Confocal microscopy and impression cytology are able to clarify new markers of the ocular disease. Extraglandular manifestations should be an alert more severe complications in the eye. Some models have strong sex and exocrine gland predilection, whereas aging generally worsens the disease phenotype. Although most models do not display a significant increase in corneal staining or tear secretion impairment, conjunctival infiltration and decrease in goblet cells are frequently seen.

SUMMARY

We have seen great advances in the role of inflammation in ocular, oral and extra-glandular manifestations of Sjögren's syndrome. Several mechanisms and mediators of Sjögren's syndrome have been elucidated in animal model studies.

Co-regulation of Dectin-1 and TLR2 in inflammatory response of human corneal epithelial cells induced by Aspergillus fumigates

AIM

To investigate the co-regulation of dendritic cell-associated C-type lectin-1 (Dectin-1), Toll-like receptor 2 (TLR2), and relative chemotactic factors in the Telomease-immortalized human corneal epithelial (THCE) cells after exposure to Aspergillus fumigatus (Af) hyphae.

METHODS

The normal THCE cells were investigated as control. After cultured in vitro with Af hyphae, with or without laminarin and anti-TLR2 antibody for 4, 8, 16 and 24h, THCE cells were harvested. The expression of Dectin-1, TLR2, CXCL1 and CXCL8 mRNA were measured by real-time quantitative polymerase chain reaction at the stimulation of 4, 8 and 16h separately. The protein expression of Dectin-1 and TLR2 were analyzed at 8, 16, and 24h by Western blot.

RESULTS

The mRNA expression of CXCL1 and CXCL8 increased in THCE cells after stimulated by Af hyphae. The stimulatory effects on these inflammatory chemokines were shown in a dose-dependent manner and reached the peak at 8h. Af hyphae significantly stimulated the production of Dectin-1 and TLR2 in THCE cells at both mRNA and protein levels. The protein of Dectin-1 and TLR2 gradually increased till 16h. While pretreated with laminarin (a Dectin-1 inhibitor), the expression of TLR2, CXCL1 and CXCL8 all decreased dramatically at the peak point. Interestingly, when pretreated with TLR2 neutralizing antibody, the expression of Dectin-1, CXCL1 and CXCL8 also decreased dramatically at the peak point.

CONCLUSION

These findings suggest that Dectin-1 and TLR2 co-regulated with each other after treated with inactive Af hyphae in the THCE cells, and they contribute together to the inflammatory responses by induction of chemokines CXCL1 and CXCL8.

The Matrix Metalloproteinase 9 Point-of-Care Test in Dry Eye

Dry eye is a common, multifactorial disease currently diagnosed by a combination of symptoms and signs. However, the subjective symptoms of dry eye poorly correlate to the current gold standard for diagnostic tests, reflecting the need to develop better objective tests for the diagnosis of dry eye. This review considers the role of ocular surface matrix metalloproteinase 9 (MMP-9) in dry eye and the implications of a novel point-of-care test that measures MMP-9 levels, InflammaDry (RPS, Sarasota, FL) on choosing appropriate therapeutic treatments.

Dry Eye Profiles in Patients with a Positive Elevated Surface Matrix Metalloproteinase 9 Point-of-Care Test Versus Negative Patients

PURPOSE

To compare dry eye (DE) symptoms and signs in subjects who tested positive versus those who tested negative for ocular surface matrix metalloproteinase 9 (MMP-9) using the InflammaDry point-of-care test (RPS, Sarasota, FL).

METHODS

In this cross-sectional study, individuals seen in the Miami Veterans Affairs eye clinic with DE symptoms, as evidenced by DE questionnaire 5 (DEQ5) ≥6, were given standardized questionnaires to assess DE symptoms and ocular and non-ocular pain complaints. Also, a complete evaluation was conducted to measure ocular surface signs of DE. MMP-9 testing was performed using the InflammaDry once in each eye, per the manufacturer's instructions. The main outcome measure was a comparison of DE symptoms and signs in MMP-9 positive versus negative subjects.

RESULTS

Of 128 subjects, 50 (39%) were positive for MMP-9 for InflammaDry testing in either eye. No statistically significant differences in mental health indices, DE symptoms, or ocular surface signs were seen in subjects based on MMP-9 status.

CONCLUSION

In our population, there was no difference in the DE profile by both symptoms and signs between those testing positive versus negative for MMP-9 on the ocular surface. This suggests that clinical exam alone cannot predict patients with clinically significant inflammation.

Differential Effects of Dexamethasone and Doxycycline on Inflammation and MMP Production in Murine Alkali-Burned Corneas Associated with Dry Eye

Alkali burns to the cornea are among the most devastating injuries to the eye. The purpose of this study was to evaluate the effects of dexamethasone (Dex) or doxycycline (Doxy) on protease activity and corneal complications in a combined model (CM) of alkali burn and dry eye. C57BL/6 mice were subjected to the CM for 2 or 5 days (D). Mice were topically treated either with Dex (0.1%), Dox (0.025%) or vehicle QID and observed daily for appearance of corneal perforation. Quantitative real time PCR was performed to measure expression of inflammation cytokines and matrix metalloproteinases (MMPs) in whole cornea lysates. No perforations were observed in the Dex-treated corneas. All wounds in Doxy-treated corneas were closed 2D post-injury, and they had significantly lower corneal opacity scores at days 4 and 5 post-injury compared to BSS treatment. Dex-treated corneas had the lowest corneal opacity scores. Dex treatment significantly decreased expression of IL-1β, IL-6, MMPs -1, -9, -13, and TIMP-1 after 2 days but increased levels of MMP-8, while Doxy treatment significantly decreased IL-1β, IL-6, MMP-8, and -9, compared to vehicle. Decreased MMP-1, -9 and -13 immunoreactivity and gelatinolytic activity were seen in corneas treated with Doxy and Dex compared to vehicle. Increased neutrophil infiltration and myeloperoxidase activity was noted in the vehicle group compared to Dex 2 days post-injury. These findings demonstrate that early initiation of anti-inflammatory therapy is very efficacious in preserving corneal clarity and facilitating wound healing, while modulating MMP production and suppressing neutrophil infiltration.

Improvement of Outcome Measures of Dry Eye by a Novel Integrin Antagonist in the Murine Desiccating Stress Model

PURPOSE

We investigated the effects of GW559090, a novel, competitive, and high-affinity α4 integrin antagonist, in a murine model of dry eye. Through interaction with vascular cell adhesion molecule 1 (VCAM-1) and fibronectin α4β1 integrin is involved in leukocyte trafficking and activation.

METHODS

Female C57BL/6 mice, aged 6 to 8 weeks, were subjected to desiccating stress (DS). Bilateral topical twice daily treatment with GW559090 was compared to vehicle-treated controls. Treatment was initiated at the time of DS induction. Treatment effects were assessed on corneal staining with Oregon Green Dextran (OGD) and expression of inflammatory markers in ocular surface tissues by real time PCR. Dendritic cell activation was measured in draining cervical lymph nodes (CLN) by flow cytometry. Separate groups of mice received GW559090 subcutaneously to evaluate the effects of systemic administration on corneal staining and cells in CLN.

RESULTS

Topical GW559090 significantly reduced corneal uptake of OGD compared to vehicle-treated disease controls in a dose-dependent manner (1, 3, 10, and 30 mg/mL) with 30 mg/mL showing the greatest reduction in OGD staining. When administered topically, corneal expression of IL-1α, matrix metalloproteinase (MMP)-9, chemokine ligand 9 (CXCL9), and TGF-β1 was reduced in GW559090-treated eyes. Topical treatment with GW559090 decreased dendritic cell activation in lymph nodes. The effects on corneal staining and cellular composition in CLN were not reproduced by systemic administration of GW559090, suggestive of a local role for integrin antagonism in the treatment of dry eye.

CONCLUSION

The novel α4 integrin antagonist, GW559090, improved outcome measures of corneal staining and ocular surface inflammation in this murine model of dry eye. These results indicate the potential of this novel agent for the treatment of dry eye disease.

Clusterin Seals the Ocular Surface Barrier in Mouse Dry Eye

Dry eye is a common disorder caused by inadequate hydration of the ocular surface that results in disruption of barrier function. The homeostatic protein clusterin (CLU) is prominent at fluid-tissue interfaces throughout the body. CLU levels are reduced at the ocular surface in human inflammatory disorders that manifest as severe dry eye, as well as in a preclinical mouse model for desiccating stress that mimics dry eye. Using this mouse model, we show here that CLU prevents and ameliorates ocular surface barrier disruption by a remarkable sealing mechanism dependent on attainment of a critical all-or-none concentration. When the CLU level drops below the critical all-or-none threshold, the barrier becomes vulnerable to desiccating stress. CLU binds selectively to the ocular surface subjected to desiccating stress in vivo, and in vitro to the galectin LGALS3, a key barrier component. Positioned in this way, CLU not only physically seals the ocular surface barrier, but it also protects the barrier cells and prevents further damage to barrier structure. These findings define a fundamentally new mechanism for ocular surface protection and suggest CLU as a biotherapeutic for dry eye.

Desiccating Stress-Induced MMP Production and Activity Worsens Wound Healing in Alkali-Burned Corneas

PURPOSE

To evaluate the effects of dry eye on ocular surface protease activity and sight threatening corneal complications following ocular surface chemical injury.

METHODS

C57BL/6 mice were subjected to unilateral alkali burn (AB) with or without concomitant dry eye for 2 or 5 days. Mice were observed daily for appearance of corneal perforation. Whole corneas were harvested and lysed for RNA extraction. Quantitative real-time PCR was performed to measure expression of inflammation cytokines, matrix metalloproteinases (MMP). Matrix metalloproteinase-9 activity, gelatinase activity, and myeloperoxidase (MPO) activity were evaluated in corneal lysates. Presence of infiltrating neutrophils was evaluated by immunohistochemistry and flow cytometry.

RESULTS

Eyes subjected to the combined model of AB and dry eye (CM) had 20% sterile corneal perforation rate as soon as 1 day after the initial injury, which increased to 35% by 5 days, delayed wound closure and increased corneal opacity. Increased levels of IL-1β, -6, and MMPs-1, -3, -8, -9, and -13, and chemokine (C-X-C motif) ligand 1 (CSCL1) transcripts were found after 2 days in CM compared with AB corneas. Increased MMP-1, -3, -9, and -13 immunoreactivity and gelatinolytic activity were seen in CM corneas compared with AB. Increased neutrophil infiltration and MPO activity was noted in the CM group compared with AB 2 days post injury.

CONCLUSIONS

Desiccating stress worsens outcome of ocular AB, creating a cytokine and protease storm with greater neutrophil infiltration, increasing the risk of corneal perforation.

Dectin-1 agonist curdlan modulates innate immunity to Aspergillus fumigatus in human corneal epithelial cells

AIM

To explore the immunomodulatory effects of curdlan on innate immune responses against Aspergillus fumigatus (A. fumigatus) in cultured human corneal epithelial cells (HCECs), and whether C-type lectin receptor Dectin-1 mediates the immunomodulatory effects of curdlan.

METHODS

The HCECs were stimulated by curdlan in different concentrations (50, 100, 200, 400 µg/mL) for various time. Then HCECs pretreated with or without laminarin (Dectin-1 blocker, 0.3 mg/mL) and curdlan were stimulated by A. fumigatus hyphae. The mRNA and protein production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The protein level of Dectin-1 was measured by Western blot.

RESULTS

Curdlan stimulated mRNA expression of TNF-α and IL-6 in a dose and time dependent manner in HCECs. Curdlan pretreatment before A. fumigatus hyphae stimulation significantly enhanced the expression of TNF-α and IL-6 at mRNA and protein levels compared with A. fumigatus hyphae stimulation group (P<0.05). Both curdlan and A. fumigatus hyphae up-regulated Dectin-1 protein expression in HCECs, and Dectin-1 expression was elevated to 1.5- to 2-fold by curdlan pretreatment followed hyphae stimulation. The Dectin-1 blocker laminarin suppressed the mRNA expression and protein production of TNF-α and IL-6 induced by curdlan and hyphae (P<0.05).

CONCLUSION

These findings demonstrated that curdlan pretreatment enhanced the inflammatory response induced by A. fumigatus hyphae in HCECs. Dectin-1 is essential for the immunomodulatory effects of curdlan. Curdlan may have high clinical application values in fungal keratitis treatment.

Differential roles of MMP-9 in early and late stages of dystrophic muscles in a mouse model of Duchenne muscular dystrophy

Matrix metalloprotease (MMP)-9 is an endopeptidase associated with the pathogenesis of Duchenne muscular dystrophy (DMD). The precise function of MMP-9 in DMD has not been elucidated to date. We investigated the effect of genetic ablation of MMP-9 in the mdx mouse model (mdx/Mmp9(-/-)). At the early disease stage, the muscles of mdx/Mmp9(-/-) mice showed reduced necrosis and neutrophil invasion, accompanied by down-regulation of chemokine MIP-2. In addition, muscle regeneration was enhanced, which coincided with increased macrophage infiltration and upregulation of MCP-1, and resulted in increased muscle strength. The mdx/Mmp9(-/-) mice also displayed accelerated upregulation of osteopontin expression in skeletal muscle at the acute onset phase of dystrophy. However, at a later disease stage, the mice exhibited muscle growth impairment through altered expression of myogenic factors, and increased fibroadipose tissue. These results showed that MMP-9 might have multiple functions during disease progression. Therapy targeting MMP-9 may improve muscle pathology and function at the early disease stage, but continuous inhibition of this protein may result in the accumulation of fibroadipose tissues and reduced muscle strength at the late disease stage.

Effects of L-carnitine, erythritol and betaine on pro-inflammatory markers in primary human corneal epithelial cells exposed to hyperosmotic stress

PURPOSE

To explore the effects of osmoprotectants on pro-inflammatory mediator production in primary human corneal epithelial cells (HCECs) exposed to hyperosmotic stress.

METHODS

HCECs cultured in iso-osmolar medium (312 mOsM) were switched to hyperosmotic media with or without prior incubation with 2-20 mM of l-carnitine, erythritol or betaine for different time periods. The mRNA expression and protein production of pro-inflammatory markers in HCECs were evaluated by RT-qPCR and ELISA.

RESULTS

Hyperosmolar media significantly stimulated the mRNA and protein expression of pro-inflammatory cytokines, TNF-α, IL-1β and IL-6, and chemokines, IL-8, CCL2 and CCL20 in HCECs in an osmolarity dependent manner. The stimulated expression of these pro-inflammatory mediators was significantly but differentially suppressed by l-carnitine, erythritol or betaine. l-Carnitine displayed the greatest inhibitory effects and down-regulated 54-77% of the stimulated mRNA levels of TNF-α (down from 12.3-5.7 fold), IL-1β (2.2-0.9 fold), IL-6 (7.3-2.9 fold), IL-8 (4.6-2.0 fold), CCL2 (15.3-3.5 fold) and CCL20 (4.1-1.5 fold) in HCECs exposed to 450 mOsM. The stimulated protein production of TNF-α, IL-1β, IL-6 and IL-8 was also significantly suppressed by l-carnitine, erythritol and betaine. l-carnitine suppressed 49-79% of the stimulated protein levels of TNF-α (down from 81.3 to 17.4 pg/ml), IL-1β (56.9-29.2 pg/ml), IL-6 (12.8-4.6 ng/ml) and IL-8 (21.2-10.9 ng/ml) by HCECs exposed to 450 mOsM. Interestingly, hyperosmolarity stimulated increase in mRNA and protein levels of TNF-α, IL-1β and IL-6 were significantly suppressed by a transient receptor potential vanilloid channel type 1 (TRPV1) activation inhibitor capsazepine.

CONCLUSIONS

l-carnitine, erythritol and betaine function as osmoprotectants to suppress inflammatory responses via TRPV1 pathway in HCECs exposed to hyperosmotic stress. Osmoprotectants may have efficacy in reducing innate inflammation in dry eye disease.

Effects of Dry Eye Therapies on Environmentally Induced Ocular Surface Disease

PURPOSE

To evaluate the effectiveness of artificial tears and corticosteroids on mitigating the acute ocular surface response to low-humidity environments.

DESIGN

Single-group, crossover clinical trial.

METHODS

Twenty subjects with aqueous deficient dry eye were enrolled. Subjects meeting inclusion criteria at visit 1 were exposed to a baseline 90-minute low-humidity environment at visit 2. They then used artificial tears for 2 weeks prior to low-humidity exposure at visit 3, followed by 0.1% dexamethasone for 2 weeks prior to the final low-humidity exposure at visit 4. Outcome measures included corneal and conjunctival staining, blink rate, and irritation symptoms before and after each low-humidity exposure. Digital polymerase chain reaction (PCR) was performed to measure HLA-DR RNA transcripts in conjunctival cells taken by impression cytology at each visit.

RESULTS

There was significantly less corneal and conjunctival epitheliopathy after the low-humidity exposure at visit 4 compared to after the low-humidity exposure at visit 3 (P = .003). Subjects reported significantly less eye irritation during the low-humidity exposure after using the dexamethasone (visit 4) compared to artificial tears (visit 3) (P = .01). HLA-DR transcripts significantly decreased after the stress at visit 4 (post dexamethasone) compared to visit 2.

CONCLUSION

Our study demonstrates that corticosteroid eye drops mitigate the acute adverse effects of an experimental low-humidity challenge, likely owing to suppression of stress-activated inflammatory pathways. While extended use of corticosteroids is not indicated, other anti-inflammatory therapies with activity against stress-activated pathways may prove as effective.

In Vivo and Impression Cytology Study on the Effect of Compatible Solutes Eye Drops on the Ocular Surface Epithelial Cell Quality in Dry Eye Patients

The aim of this study is to investigate in vivo and ex vivo ocular surface alterations induced by dry eye disease and modification after osmoprotective therapy. Forty-eight eyes of 24 patients suffering from dry eye have been recruited. All patients received Optive (compatible solutes) eye drops in one randomly selected eye and Hylogel (sodium hyaluronate 0,2%) in the other. Follow-up included a baseline visit and further examination 30-, 60-, and 90-day intervals (which comprises clinical evaluation, in vivo confocal microscopy-IVCM-of the ocular surface, and conjunctival impression cytology). No significant difference in Schirmer I Test, TBUT, and vital staining results was observed during the follow-up period in both groups. IVCM showed in all patients an improvement of ocular surface epithelial morphology and signs of inflammation (oedema and keratocyte activation). However, these modifications were more evident in patients treated with Optive therapy. A significant reduction of the expression of MMP9 and IL6 in Optive group was observed during the follow-up period in comparison to Hylogel treatment. Our results show that in dry eye disease therapy based on osmoprotective eye drops determines a reduction of inflammatory activation of ocular surface, with consequent improvement of the quality of corneal and conjunctival epithelium.

The role of Syk signaling in antifungal innate immunity of human corneal epithelial cells

BACKGROUND

Fungal keratitis is a kind of intractable and sight-threatening diseases. Spleen-tyrosine kinase (Syk) is a non-receptor tyrosine kinase, which plays an important role in the signaling pathway of the receptors. In the current study, we investigate the expression and function of Syk in human corneal epithelial cells with Aspergillus fumigatus (A. fumigatus) infection.

METHODS

Cultured telomerase-immortalized human corneal epithelial cells (THCEs) were treated with A. fumigatus hyphae with or without treatment of Syk inhibitors. Activation of Syk and the role of Syk in regulating inflammatory cytokines and chemokines expression were evaluated. The mRNA expression was determined by real time PCR, and protein activation was measured by western blotting.

RESULTS

Syk protein was detected in THCEs, and its activation was enhanced after treatment of A. fumigatus hyphae. Expression of inflammatory cytokines (IL-1β and IL-6) and chemokines (IL-8 and CXCL1) mRNA were significantly increased after stimulation of A. fumigatus hyphae in THCEs. Activation of Syk and expression of IL-1β, IL-6, IL-8 and CXCL1 by A. fumigatus hyphae were blocked by Syk inhibitors.

CONCLUSION

These findings demonstrate that normal human corneal epithelial cells produce Syk, and Syk activation plays an important role in regulating A. fumigatus hyphae-induced inflammatory responses in THCEs.

Anti-inflammatory effects of hinokitiol on human corneal epithelial cells: an in vitro study

PURPOSE

This study assessed the anti-inflammatory effect and mechanism of action of hinokitiol in human corneal epithelial (HCE) cells.

METHODS

HCE cells were incubated with different concentrations of hinokitiol or dimethylsulfoxide (DMSO), which served as a vehicle control. Cell viability was evaluated using Cell Counting Kit-8 (CCK-8) assay. After polyriboinosinic:polyribocytidylic acid (poly(I:C)) stimulus, cells with or without hinokitiol were evaluated for the mRNA and protein levels of interleukin-8 (IL-8), interleukin-6 (IL-6), and interleukin-1β (IL-1β) using real-time PCR analysis and an enzyme-linked immunosorbent assay (ELISA), respectively. Nuclear and cytoplasmic levels of nuclear factor kappa B (NF-κB) p65 protein and an inhibitor of NF-κB α (IκBα) were evaluated using western blotting.

RESULTS

There were no significant differences among the treatment concentrations of hinokitiol compared with cells incubated in medium only. Incubating with 100 μM hinokitiol significantly decreased the mRNA levels of IL-8 to 58.77±10.41% (P<0.01), IL-6 to 64.64±12.71% (P<0.01), and IL-1β to 54.19±8.10% (P<0.01) compared with cells stimulated with poly(I:C) alone. The protein levels of IL-8, IL-6, and IL-1β had similar trend. Further analysis revealed that hinokitiol maintained the levels of IκBα and significantly reduced NF-κB p65 subunit translocation to the nucleus which significantly inhibiting the activation of the NF-κB signal pathway.

CONCLUSION

Hinokitiol showed a significant protective effect against ocular surface inflammation through inhibiting the NF-κB pathway, which may indicate the possibility to relieve the ocular surface inflammation of dry eye syndrome (DES).

Efficacy and safety of two new formulations of artificial tears in subjects with dry eye disease: a 3-month, multicenter, active-controlled, randomized trial

Purpose

To evaluate and compare the efficacy and safety of two investigational artificial tear formulations (CHO-1 and CHO-2) containing carmellose sodium, hyaluronic acid at different concentrations, and osmoprotectants, with a standard carmellose sodium-containing formulation (Refresh Tears [RT]) in the treatment of dry eye disease.

Subjects and methods

In this 3-month, double-masked, multicenter study, subjects (n=305) were randomized 1:1:1 to receive CHO-1, CHO-2, or RT, used as needed but at least twice daily. The primary endpoint was change in ocular surface disease index (OSDI) score from baseline to day 90. Other key outcomes included symptoms evaluated on a visual analog scale, corneal and conjunctival staining, and adverse events.

Results

OSDI scores and dry eye symptoms showed a rapid and sustained reduction from baseline in each group. Both CHO-1 and CHO-2 met the primary efficacy endpoint of noninferiority to RT in day 90 OSDI score change from baseline. OSDI ocular symptoms subscale improved more with CHO-1 than CHO-2 (P=0.048). In subjects with clinically relevant baseline ocular surface staining (>14 total score of a maximum of 55), day 90 improvements were greater with CHO-1 and CHO-2 than RT (P≤0.044). Day 90 improvements in OSDI ocular symptoms subscale scores were also greater with CHO-1 than RT (P<0.007) in subjects with clinically relevant ocular staining. All treatments were well tolerated.

Conclusion

Both combination artificial tear formulations were efficacious and well tolerated in subjects with dry eye. CHO-1 demonstrated the best performance in improving ocular symptoms and reducing ocular staining in this heterogeneous study population.

Efficacy of the mineral oil and hyaluronic acid mixture eye drops in murine dry eye

Purpose

To investigate the therapeutic effects of mineral oil (MO) and hyaluronic acid (HA) mixture eye drops on the tear film and ocular surface in a mouse model of experimental dry eye (EDE).

Methods

Eye drops consisting of 0.1% HA alone or mixed with 0.1%, 0.5%, or 5.0% MO were applied to desiccating stress-induced murine dry eyes. Tear volume, corneal irregularity score, tear film break-up time (TBUT), and corneal fluorescein staining scores were measured at 5 and 10 days after treatment. Ten days after treatment, goblet cells in the conjunctiva were counted after Periodic acid-Schiff staining.

Results

There was no significant difference in the tear volume between desiccating stress-induced groups. The corneal irregularity score was lower in the 0.5% MO group compared with the EDE and HA groups. The 0.5% and 5.0% MO groups showed a significant improvement in TBUT compared with the EDE group. Mice treated with 0.1% and 0.5% MO mixture eye drops showed a significant improvement in fluorescein staining scores compared with the EDE group and the HA group. The conjunctival goblet cell count was higher in the 0.5% MO group compared with the EDE group and HA group.

Conclusions

The MO and HA mixture eye drops had a beneficial effect on the tear films and ocular surface of murine dry eye. The application of 0.5% MO and 0.1% HA mixture eye drops could improve corneal irregularity, the corneal fluorescein staining score, and conjunctival goblet cell count compared with 0.1% HA eye drops in the treatment of EDE.

Neurostimulation of the lacrimal nerve for enhanced tear production

PURPOSE

To design a proof-of-concept study to assess the effect of lacrimal nerve stimulation (LNS) with an implantable pulse generator (IPG) to increase aqueous tear production.

METHODS

Experimental animal study design of 6 Dutch Belted rabbits. Ultra high-resolution optical coherence tomography (UHR-OCT) quantified tear production by measuring the baseline tear volume of each rabbit's OD and OS. A neurostimulator was implanted adjacent to the right lacrimal nerve. After 2 minutes of LNS (100 μs, 1.6 mA, 20 Hz, 5-8 V), the tear volumes were measured with UHR-OCT. The change in tear volume was quantified and compared with the nonstimulated OS. Three rabbits underwent chronic LNS (100 μs, 1.6 mA, 10 Hz, 2 V) and their lacrimal glands were harvested for histopathologic analysis.

RESULTS

The UHR-OCT imaging of the OD tear volume showed a 441% average increase in tear production after LNS as a percent of baseline. After stimulation, OD had statistically significant greater increase in tear volumes than OS (p = 0.028, Wilcoxon test). Poststimulation OD tear volumes were significantly greater compared with baseline (p = 0.028, Wilcoxon test). Histopathologic examination of the lacrimal glands showed no discernible tissue damage from chronic neurostimulation. In addition, there were no gross adverse effects on the general well-being of the animals due to chronic stimulation.

CONCLUSIONS

LNS with an IPG appears to increase aqueous tear production. Chronic LNS showed no histopathologic lacrimal gland damage. This study suggests that LNS is a promising new treatment strategy to increase aqueous tear production.

Topical fluorometholone treatment for ocular dryness in patients with Sjögren syndrome: a randomized clinical trial in China

The purpose of the study was to evaluate the efficacy of an ophthalmic solution containing 0.1% fluorometholone (FML) and 0.1% sodium hyaluronate (HA) for the treatment of ocular dryness in Sjögren syndrome (SS) patients.Forty SS patients were randomly assigned to the FML or cyclosporin A (CsA) treatment groups. The FML group was treated with 0.1% FML and 0.1% HA, and the CsA group was treated with 0.5% CsA and 0.1% HA. Primary outcomes were corneal fluorescein staining (CFS), the Ocular Surface Disease Index (OSDI) score, conjunctival goblet cell density, and the severity of conjunctival congestion. Patients were also evaluated based on tear film breakup time (TFBUT) and the Schirmer test. After 8 weeks of treatment, the mean CFS scores were significantly lower in both the groups, compared with the baseline values, and the CFS score of the FML group at week 2 was significantly lower than that of the CsA group (P = 0.042). The OSDI scores improved significantly in both the groups throughout the study, and the OSDI score in the FML group at week 4 was significantly lower than that of the CsA group (P = 0.042). After 8 weeks of therapy, the conjunctival goblet cell density was significantly higher in both the groups (P < 0.001 for both) compared with the baseline values. Conjunctival congestion was reduced in both the groups throughout the study, and the severity in the FML group was significantly less at week 4 compared with that in the CsA group (P = 0.035). The TFBUT in the FML group at week 8 was significantly longer than in the CsA group (P = 0.04). Treatment using topical 0.1% FML provided faster improvement in the symptoms of ocular dryness in SS patients compared with topical 0.5% CsA.

[Treating severe keratoconjunctivitis sicca]

Keratoconjunctivitis sicca is a widespread disease with a complex multifactorial pathogenesis. Current understanding of its pathogenesis and existing treatments are summarized in this literature review.

Effects of topical loteprednol etabonate on tear cytokines and clinical outcomes in moderate and severe meibomian gland dysfunction: randomized clinical trial

PURPOSE

To assess tear cytokine levels and clinical outcomes in moderate and severe meibomian gland dysfunction (MGD) after 2 months of treatment with topical loteprednol etabonate and eyelid scrubs with warm compresses vs eyelid scrubs with warm compresses alone.

DESIGN

Randomized controlled trial.

METHODS

Patients with moderate and severe MGD were randomized into 2 groups: topical loteprednol etabonate and eyelid scrubs with warm compresses (Group I, 34 eyes) or eyelid scrubs with warm compresses (Group II, 36 eyes). We evaluated cytokine levels, tear film break-up time (TBUT), corneal and conjunctival fluorescein staining, biomicroscopic examination of lid margins and meibomian glands, and the Ocular Surface Disease Index before initiating treatment and 1 month and 2 months after treatment.

RESULTS

There were significant decreases in the levels of interleukin (IL)-6, IL-8, and IL-1β in Group I, and IL-6 and IL-8 in Group II. Moreover, the observed decreases of these cytokines in Group I were attributed to a remarkable decrease between treatment and 1 month after treatment. In Group I, there were improvements in all of the clinical outcomes, with prominent improvement in TBUT, corneal and conjunctival fluorescein staining, and meibum quality after 1 month of treatment, compared with Group II. An improvement in meibomian gland expressibility and MGD stage reduction were more remarkable in Group I.

CONCLUSIONS

Topical loteprednol etabonate and eyelid scrubs with warm compresses were tolerated and efficacious for the treatment of moderate and severe MGD. We suggest that such beneficial effects could manifest after 1 month.

Practical issues concerning tear protein assays in dry eye

Dry eye is a common clinical condition diagnosed by cumulative evidence of symptoms and signs. Many new treatments in dry eye are either expensive, invasive, have potential for side effects, or are not easily accessible. In severe dry eye, the ideal modality of treatment to begin with is often not clear as specific molecular disturbances are not evident from just examination of clinical manifestations. Assessing the effects of ongoing treatment is not straight forward since there is lack of agreement between clinical signs and symptoms. There is a need to have more objective methods of selecting treatment for dry eye and monitoring the effect of treatment. Recently, there are many new technologies applied to the discovery of tear biomarkers, for e.g., mass spectrometry based proteomics techniques and multiplex assays such as the bead-based sandwich indirect immunofluorescent assays. Tear proteins assays have even been made available as point-of-care devices. This review focuses on the evidence for the involvements of tear proteins in dry eye, possible changes in tear concentrations with therapy and the strength of evidence regarding dry eye pathology. Much remains to be done in terms of developing office-based assays and ascertaining their reliability, but current evidence suggests that tear proteins have a role in the clinical practice of dry eye.