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

Bilateral Sutureless Application of Human Dehydrated Amniotic Membrane with a Specialised Bandage Contact Lens for Moderate-to-Severe Dry Eye Disease: A Prospective Study with 1-Month Follow-Up

Purpose

To assess changes in symptoms and ocular surface signs following a bilateral sutureless treatment of dehydrated amniotic membrane (dAM) under a specialised bandage contact lens (sBCL) in patients with moderate-to-severe dry eye disease (DED).

Patients and Methods

In this prospective pre-post interventional study, 35 patients diagnosed with moderate-to-severe DED, with an Ocular Surface Disease Index (OSDI) score >30 on current treatment, were enrolled. Assessments were conducted at baseline (day -30), after 30 days run-in with no additional treatment (day 0 - control), and 30 days post sBCL+dAM treatment (day 30 - treatment). Intervention involved two successive bilateral 4-5 day sutureless applications of dAM (17mm diameter, with a 6 mm central aperture, Omnigen® VIEW) under an 18mm sBCL (OmniLenz®). Symptomatology and ocular signs were measured using OSDI, Dry Eye Questionnaire-5 (DEQ-5), Symptom Assessment iN Dry Eye (SANDE), and other ocular surface health indicators including non-invasive breakup time, corneal and conjunctival staining, and lid wiper epitheliopathy length and width (LWE).

Results

While symptomatology remained stable during the 30-day no-treatment run-in, 1-month post-dAM treatment, there was a significant reduction in OSDI scores (from 55.8 to 32.3, p<0.001), DEQ-5 (from 14.6 to 10.0, p<0.001), SANDE frequency (from 65.2 to 43.6, p<0.001), and SANDE severity (from 59.8 to 41.1, p<0.001). Additionally, there was a notable decrease in the width of LWE staining, from grade 2 (50-75% of the lid wiper) to grade 1 (25-50% of the lid wiper) (p=0.011).

Conclusion

A bilateral 8-10-day treatment duration with dAM applied with sBCL demonstrated a 31 to 42% improvement in symptomatology and a decrease in ocular surface signs of mechanical stress. This innovative bilateral treatment approach offers a promising treatment modality for patients with refractory moderate-to-severe DED.

Intense pulsed light therapy for ocular surface diseases

Intense pulsed light (IPL) is a non-laser, high-intensity light source that has been shown to play a valuable role in dermatology and has been adopted in ophthalmology for treating meibomian gland dysfunction (MGD). In this review, we discuss the mechanism of action of IPL, including its benefits in ophthalmology. IPL therapy has been shown to improve tear film stability, meibomian gland (MG) function, and subjective symptoms of ocular dryness in MGD patients. Moreover, emerging evidence suggests that IPL therapy is beneficial for other ocular surface diseases, such as blepharitis and chalazia. Hence, it can be inferred that IPL has potential as a therapeutic modality in future applications. Large clinical and experimental trials are needed to exploit the full potential of IPL as a treatment for recurrent chalazia, Sjögren's syndrome, and other causes of dry eye disease (DED). This paper reviews the published literature related to the application of IPL for treating ocular surface diseases.

Targeting inflammasomes and pyroptosis in retinal diseases-molecular mechanisms and future perspectives

Retinal diseases encompass various conditions associated with sight-threatening immune responses and are leading causes of blindness worldwide. These diseases include age-related macular degeneration, diabetic retinopathy, glaucoma and uveitis. Emerging evidence underscores the vital role of the innate immune response in retinal diseases, beyond the previously emphasized T-cell-driven processes of the adaptive immune system. In particular, pyroptosis, a newly discovered programmed cell death process involving inflammasome formation, has been implicated in the loss of membrane integrity and the release of inflammatory cytokines. Several disease-relevant animal models have provided evidence that the formation of inflammasomes and the induction of pyroptosis in innate immune cells contribute to inflammation in various retinal diseases. In this review article, we summarize current knowledge about the innate immune system and pyroptosis in retinal diseases. We also provide insights into translational targeting approaches, including novel drugs countering pyroptosis, to improve the diagnosis and treatment of retinal diseases.

Low Rate of Postoperative Pterygium Recurrence in Patients under Treatment with Low-Dose Oral Doxycycline for Chronic Blepharitis: A First Report

PURPOSE

Low doses of systemic doxycycline (LD-SD) inhibit angiogenesis and the expression of matrix metalloproteases, which are determinants of pterygium progression. This study aimed to compare the recurrence rate and visual outcome of pterygium excision in patients undergoing chronic treatment with LD-SD for chronic refractory blepharitis and LD-SD-naive patients.

METHODS

A retrospective analysis of patients that underwent surgical excision and conjunctival graft apposition was conducted. Patients were divided in a TETRA group (under LD-SD treatment at the moment of surgery) and a control group. The main outcome was the rate of recurrence at 1 year postoperatively. Secondary outcomes were the comparisons of surface regularity, visual quality, and dry-eye symptoms at 6-week, 6-month, and 1-year follow-up in the two groups.

RESULTS

The TETRA group showed a significantly lower rate of 1-year recurrence both in primary (p = 0.034) and recurrent (p < 0.001) pterygia. The best corrected visual acuity (BCVA), astigmatic error, corneal total root mean square (RMS), and ocular surface disease index (OSDI) significantly reduced during the follow-up in both groups. The surface asymmetry index and high-order aberrations (HOAs) significantly reduced only in the TETRA group. The final BCVA was significantly higher, while the OSDI score and total RMS and HOAs were significantly lower in the TETRA group compared to the control.

CONCLUSIONS

Patients under treatment with LD-SD showed a lower rate of recurrence at 1-year follow-up compared to controls. These patients also experienced higher BCVA and surface regularity and less dry-eye symptoms.

Sialylated IVIg promotes clinical improvements in a rabbit dry eye model by regulating inflammatory cytokines

Dry eye disease (DED) is caused by a loss of homeostasis of the tear film, which results in visual disturbance, ocular surface inflammation and damage, and neurosensory abnormalities. Although it is prevalent in 5-50% of the global population, there are limited clinical options for its treatment. This study explored the potential use of human intravenous immunoglobulin (IVIg) and its enriched fractions of sialylation, sialylated IVIg (sIVIg), as a treatment for DED. Fifteen female New Zealand white rabbits were topically instilled with 0.2% benzalkonium chloride (BAC) twice daily for five consecutive days to induce experimental dry eye. Saline, 0.4% IVIg, or 0.04% sIVIg eye drops were instilled twice daily for 20 consecutive days. Clinical evaluations, such as non-invasive tear break-up time (NIBUT) and corneal fluorescein staining (CFS), were conducted. mRNA levels of mucin 4, mucin 16, TNF-α, IL-1β, MMP9, IL-10, TGF-β, and CD209 in rabbit conjunctival tissues were examined using reverse transcription polymerase chain reaction (RT-PCR) or quantitative RT-PCR (qRT-PCR). The relationships between CD209 family members in rabbits and various mammalian species were analyzed using a phylogenetic tree. IVIg or sIVIg treatment resulted in clinical improvements in the rabbit DED model. The inflammatory cytokines, TNF-α and IL-1β, were increased and mucin 4 and mucin 16, cell surface-associated mucins, were decreased in BAC-induced dry eye. Following IVIg or sIVIg treatment, inflammatory cytokines decreased, whereas the anti-inflammatory cytokine, IL-10, increased substantially. Moreover, a 10-fold lower sIVIg treatment dose resulted in prolonged IL-10 production, representing a significantly improved DED compared to IVIg. Furthermore, the expression of rabbit CD209 mRNA in the rabbit conjunctiva and its close relationship with primate homologs suggest that it may interact with IVIg or sIVIg to promote IL-10 expression, as previously described in humans. At a lower dosage, sIVIg showed a more efficient improvement in DED, making it a promising new candidate medication for DED.

Comparison of deep learning-assisted blinking analysis system and Lipiview interferometer in dry eye patients: a cross-sectional study

BACKGROUND

Abnormal blinking pattern is associated with ocular surface diseases. However, blink is difficult to analyze due to the rapid movement of eyelids. Deep learning machine (DLM) has been proposed as an optional tool for blinking analysis, but its clinical practicability still needs to be proven. Therefore, the study aims to compare the DLM-assisted Keratograph 5M (K5M) as a novel method with the currently available Lipiview in the clinic and assess whether blinking parameters can be applied in the diagnosis of dry eye disease (DED).

METHODS

Thirty-five DED participants and 35 normal subjects were recruited in this cross-sectional study. DED questionnaire and ocular surface signs were evaluated. Blinking parameters including number of blinks, number of incomplete blinking (IB), and IB rate were collected from the blinking videos recorded by the K5M and Lipiview. Blinking parameters were individually collected from the DLM analyzed K5M videos and Lipiview generated results. The agreement and consistency of blinking parameters were compared between the two devices. The association of blinking parameters to DED symptoms and signs were evaluated via heatmap.

RESULTS

In total, 140 eyes of 70 participants were included in this study. Lipiview presented a higher number of IB and IB rate than those from DLM-assisted K5M (P ≤ 0.006). DLM-assisted K5M captured significant differences in number of blinks, number of IB and IB rate between DED and normal subjects (P ≤ 0.035). In all three parameters, DLM-assisted K5M also showed a better consistency in repeated measurements than Lipiview with higher intraclass correlation coefficients (number of blinks: 0.841 versus 0.665; number of IB: 0.750 versus 0.564; IB rate: 0.633 versus 0.589). More correlations between blinking parameters and DED symptoms and signs were found by DLM-assisted K5M. Moreover, the receiver operating characteristic analysis showed the number of IB from K5M exhibiting the highest area under curve of 0.773.

CONCLUSIONS

DLM-assisted K5M is a useful tool to analyze blinking videos and detect abnormal blinking patterns, especially in distinguishing DED patients from normal subjects. Large sample investigations are therefore warranted to assess its clinical utility before implementation.

Inflammation mechanism and anti-inflammatory therapy of dry eye

Dry eye is a widespread chronic inflammatory disease that causes fatigue, tingling, burning, and other symptoms. Dry eye is attributed to rheumatic diseases, diabetes, hormone disorders, and contact lenses, which activate inflammatory pathways: mitogen-activated protein kinases (MAPK) and nuclear factor-B (NF-κB), promote macrophage inflammatory cell and T cell activation, and inflammation factors. Clinicians use a combination of anti-inflammatory drugs to manage different symptoms of dry eye; some of these anti-inflammatory drugs are being developed. This review introduces the dry eye inflammation mechanisms and the involved inflammatory factors. We also elucidate the anti-inflammatory drug mechanism and the detection limits.

Ectoine, from a Natural Bacteria Protectant to a New Treatment of Dry Eye Disease

Ectoine, a novel natural osmoprotectant, protects bacteria living in extreme environments. This study aimed to explore the therapeutic effect of ectoine for dry eye disease. An experimental dry eye model was created in C57BL/6 mice exposed to desiccating stress (DS) with untreated mice as controls (UT). DS mice were dosed topically with 0.5-2.0% of ectoine or a vehicle control. Corneal epithelial defects were detected via corneal smoothness and Oregon Green dextran (OGD) fluorescent staining. Pro-inflammatory cytokines and chemokines were evaluated using RT-qPCR and immunofluorescent staining. Compared with UT mice, corneal epithelial defects were observed as corneal smoothness irregularities and strong punctate OGD fluorescent staining in DS mice with vehicle. Ectoine treatment protected DS mice from corneal damage in a concentration-dependent manner, and ectoine at 1.0 and 2.0% significantly restored the corneal smoothness and reduced OGD staining to near normal levels. Expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and chemokines CCL3 and CXCL11 was significantly elevated in the corneas and conjunctivas of DS mice, whereas 1.0 and 2.0% ectoine suppressed these inflammatory mediators to near normal levels. Our findings demonstrate that ectoine can significantly reduce the hallmark pathologies associated with dry eye and may be a promising candidate for treating human disease.

Differential Efficacy of Small Molecules Dynasore and Mdivi-1 for the Treatment of Dry Eye Epitheliopathy or as a Countermeasure for Nitrogen Mustard Exposure of the Ocular Surface

The ocular surface comprises the wet mucosal epithelia of the cornea and conjunctiva, the associated glands, and the overlying tear film. Epitheliopathy is the common pathologic outcome when the ocular surface is subjected to oxidative stress. Whether different stresses act via the same or different mechanisms is not known. Dynasore and dyngo-4a, small molecules developed to inhibit the GTPase activity of classic dynamins DNM1, DNM2, and DNM3, but not mdivi-1, a specific inhibitor of DNM1L, protect corneal epithelial cells exposed to the oxidant tert-butyl hydroperoxide (tBHP). Here we report that, while dyngo-4a is the more potent inhibitor of endocytosis, dynasore is the better cytoprotectant. Dynasore also protects corneal epithelial cells against exposure to high salt in an in vitro model of dysfunctional tears in dry eye. We now validate this finding in vivo, demonstrating that dynasore protects against epitheliopathy in a mouse model of dry eye. Knockdown of classic dynamin DNM2 was also cytoprotective against tBHP exposure, suggesting that dynasore's effect is at least partially on target. Like tBHP and high salt, exposure of corneal epithelial cells to nitrogen mustard upregulated the unfolded protein response and inflammatory markers, but dynasore did not protect against nitrogen mustard exposure. In contrast, mdivi-1 was cytoprotective. Interestingly, mdivi-1 did not inhibit the nitrogen mustard-induced expression of inflammatory cytokines. We conclude that exposure to tBHP or nitrogen mustard, two different oxidative stress agents, cause corneal epitheliopathy via different pathologic pathways. SIGNIFICANCE STATEMENT: Results presented in this paper, for the first time, implicate the dynamin DNM2 in ocular surface epitheliopathy. The findings suggest that dynasore could serve as a new topical treatment for dry eye epitheliopathy and that mdivi-1 could serve as a medical countermeasure for epitheliopathy due to nitrogen mustard exposure, with potentially increased efficacy when combined with anti-inflammatory agents and/or UPR modulators.

The Anti-Inflammatory Effect of Multi-Wavelength Light-Emitting Diode Irradiation Attenuates Dry Eye Symptoms in a Scopolamine-Induced Mouse Model of Dry Eye

Dry eye disease is a common condition in patients of all ages, causing discomfort and potential visual problems. Current treatments, including artificial tears and anti-inflammatory drugs, have certain limitations, encouraging research into alternative therapies. We investigated the therapeutic potential of multi-wavelength light-emitting diode (LED) irradiation of mice with dry eye. First, we showed that multi-wavelength LED irradiation was non-toxic to human corneal epithelial cells and improved cell viability. We then used a scopolamine-induced mouse model of dry eye to assess the effects of multi-wavelength LED irradiation on various clinical parameters. This treatment increased the tear volume and reduced corneal irregularity, thus improving dry eye. Histological analysis revealed that multi-wavelength LED irradiation protected against corneal epithelial damage and the associated reduction in epithelial thickness and would thus improve the corneal health of dry eye patients. Multi-wavelength LED irradiation significantly reduced the corneal levels of pro-inflammatory cytokines IL-6, IL-1β, and TNF-α; the treatment was thus anti-inflammatory. Our results suggest that multi-wavelength LED irradiation may serve as a safe and effective treatment for dry eye, alleviating symptoms, reducing inflammation, and promoting corneal health.

Comparison of matrix metallopeptidase-9 expression following cyclosporine and diquafosol treatment in dry eye

PURPOSE

We sought to evaluate the expression of matrix metalloproteinase-9 (MMP-9) in dry eyes treated with 0.05% cyclosporin A and 3.0% diquafosol tetrasodium.

METHODS

One-hundred ninety-five eyes of 195 patients with dry eye were divided into three groups as follows: group 1, cyclosporin group (n = 69); group 2, diquafosol group (n = 59); and group 3, artificial tears eyes (n = 67). All eyes were treated and followed up for three months. Schirmer I Test, corneal staining, tear-film break-up time (TBUT), and tear-film MMP-9 content were measured at three months and compared between groups. The expression of MMP-9 was confirmed using a point-of-care test device (InflammaDry®; RPS Diagnostics, Sarasota, FL, USA) and graded as zero to four points.

RESULTS

At the third month, MMP-9 expression was lower in group 1 as compared with in groups 2 and 3 (p = 0.020 and 0.006, respectively). The mean MMP-9 grade according to point-of-care testing was also lower in group 1 than in groups 2 or 3 (p = 0.002 and 0.038, respectively). MMP-9 showed a correlation with corneal staining in both groups 1 and 2 (all p < 0.001) and with Schirmer I Test and TBUT in group 1 (p = 0.018 and 0.015, respectively).

CONCLUSIONS

MMP-9 expression and grade were lower after treatment with cyclosporin than after treatment with diquafosol in the dry eye disease. Anti-inflammatory treatment can decrease ocular MMP-9 levels in dry eye disease.

Neurotrophic keratitis: inflammatory pathogenesis and novel therapies

PURPOSE OF REVIEW

Neurotrophic keratitis is a rare degenerative disease characterized by decrease or absence of corneal sensation. Neurotrophic keratitis varies from mild forms with mild epitheliopathy to severe manifestations such as corneal ulceration, melting and perforation that can lead to irreversible visual loss. The cause of neurotrophic keratitis comprises a long list of diseases, medications, congenital or genetic conditions as well as trauma. The mechanism of neurotrophic keratitis is complex and multifactorial and its understanding is crucial to better address the treatment strategies. We aimed to review neurotrophic keratitis pathology, mechanisms and management.

RECENT FINDINGS

Corneal nerves are critical for the homeostasis of a healthy ocular surface. The lack of nerve-derived neuromediators and corneal-released neuropeptides, neuro-trophins and neurotrophic factors in neurotrophic keratitis leads to a decrease in trophic supply to corneal cells in addition to a decrease in afferent signaling to the brain. This results in pathological tear secretion, decreased blinking rate, corneal healing along with ocular surface and corneal inflammation. Lately, nerve growth factor in special gained emphasis as a treatment strategy targeting the disease mechanism rather than its manifestations. Other therapies, including surgical interventions, are in the pipeline of neurotrophic keratitis management. However, there are still no proper therapeutic guidelines and neurotrophic keratitis treatment remains challenging.

SUMMARY

Neurotrophic keratitis may have a devastating outcome and treatment is still challenging. Understanding the disease pathology may assist in the development of new treatment strategies. Prompt disease recognition and immediate intervention are key factors to promote corneal healing and avoid further deterioration.

Limbal Stem Cell Dysfunction Induced by Severe Dry Eye via Activation of the p38 MAPK Signaling Pathway

Severe dry eye (SDE) can cause grievous damage to the ocular surface and result in vision impairment and even blindness. To investigate the fate of limbal stem cells in SDE and the underlying mechanism, the current study established an SDE rat model by removing the extraorbital and infraorbital lacrimal glands and maintaining them in a low-humidity environment. One month after the surgery, aqueous tear secretion was reduced dramatically, blood vessels invaded into the central cornea, and inflammatory cells infiltrated into the limbal stroma. The expressions of keratin 12 and paired box gene 6 were down-regulated dramatically, while those of keratin 10, small proline-rich protein 1b, and mucin 5AC were up-regulated in the corneal epithelium of the SDE rats. Cell proliferation in the limbal epithelium was up-regulated, while the stem/progenitor marker adenosine 5'-triphosphate-binding cassette member 2 and the limbal epithelial colony-forming efficiency were decreased in the SDE condition. Furthermore, the p38 mitogen-activated protein kinase signaling pathway was activated in the limbal corneal epithelium of SDE rats. The abnormal differentiation and stemness loss in the corneal epithelium could be reversed upon treatment with a p38 inhibitor in a SDE in vivo model and in vitro hyperosmolar corneal epithelial culture conditions. These data suggest that SDE can lead to limbal stem cell dysfunction, and p38 mitogen-activated protein kinase signaling pathway activation plays an essential role in this process.

Tear inflammatory cytokines as potential biomarkers for myopic macular degeneration

Previous studies have reported that inflammatory cytokine levels increase in the intraocular fluids (aqueous humor and vitreous) of highly myopic eyes, However, there has been currently no study revealing the levels of inflammatory cytokines in tear. Therefore, this study aimed to determine tear cytokine levels of highly myopic eyes, and their relationships with myopic macular degeneration (MMD). This case-control study screened inflammatory cytokines of tear samples from 132 highly myopic and 105 emmetropic eyes using a multiplex cytokine antibody array, and cytokines showing significant intergroup differences were further validated using ProQuantum immunoassays in tear samples from another 60 highly myopic and 60 emmetropic eyes. Ultra-widefield fundus photographs of eyes were classified according to the meta-analyses of the Pathologic Myopia Classification. Associations between tear cytokine levels and MMD category were investigated. As a result, tear levels of interleukin (IL)-6, IL-13 and monocyte chemoattractant protein (MCP)-1 were screened significantly higher in highly myopic eyes than in emmetropic controls (IL-6: 11.70 ± 16.81 versus 8.22 ± 10.76 pg/mL; MCP-1: 63.60 ± 54.40 versus 33.87 ± 43.82 pg/mL; both P < 0.05). Validation assays further demonstrated the elevated concentrations of IL-6 and MCP-1 (IL-6: 13.97 ± 8.41 versus 8.06 ± 7.94 pg/mL, P < 0.001; MCP-1: 32.69 ± 8.41 versus 18.07 ± 8.41 pg/mL, P = 0.003). Tear levels of IL-6 and MCP-1 differed significantly among MMD categories (both P < 0.05). The area under receiver operating characteristic curve were 0.783 and 0.682 respectively (both P < 0.05), when using tear IL-6 and MCP-1 levels to predict the presence of MMD (category ≥2). The ordered logistic regression model also indicated that longer axial length, and higher IL-6 and MCP-1 tear levels were independent predictors of higher MMD category. In our study, highly myopic eyes presented significantly higher levels of tear IL-6 and MCP-1, which may also serve as potential biomarkers for MMD.

Emerging Strategies in Treating Corneal Alkali Burns: A Narrative Review

Corneal alkali burns represent a complex and debilitating ocular injury, necessitating innovative strategies for effective management. This narrative medical review seeks to provide a comprehensive exploration of emerging approaches in the treatment of corneal alkali burns. The primary objectives of this review are multifaceted. First, we aim to unravel the intricate pathophysiology of corneal alkali burns, delving into the immediate and long-term consequences of alkali exposure on ocular tissues. Understanding the underlying mechanisms, including oxidative stress, inflammation, and neovascularization, is essential for the development of targeted therapeutic interventions. Second, we assess the efficacy of novel treatment modalities, encompassing pharmacological agents and surgical techniques, with a focus on their ability to mitigate corneal damage, facilitate tissue regeneration, and preserve visual function. By analyzing the latest clinical findings, we aim to identify promising avenues for improved patient outcomes. Temporal dynamics play a crucial role in the healing process, and thus our review investigates the progression of corneal lymphangiogenesis and the expression patterns of key growth factors, such as vascular endothelial growth factor-C (VEGF-C). These insights into the timing of corneal healing provide valuable guidance for tailoring therapeutic interventions to specific stages of injury. Finally, we delve into regenerative therapies, particularly the potential of mesenchymal stem cells (MSCs) and their secretome as anti-inflammatory and antiangiogenic agents. By summarizing the promising results from preclinical and clinical studies, we illuminate the prospects of regenerative approaches in corneal alkali burn management. This narrative review aspires to serve as an indispensable resource for clinicians, researchers, and healthcare professionals involved in the treatment of corneal alkali burns. By addressing these objectives, we aim to foster a deeper understanding of this challenging condition, facilitate the development of innovative strategies, and ultimately enhance patient outcomes in the realm of corneal health and vision preservation.

The role of matrix metalloproteinases in infectious corneal ulcers

During infectious keratitis, the production of collagenolytic and inflammatory substances, along with increased corneal matrix metalloproteinase (MMP) activity, induces the degradation of corneal collagen and may cause postkeratitis complications, such as opacity, thinning, and corneal perforation. MMPs, especially MMP-2 and MMP-9, are overexpressed in infectious keratitis and sustained over time by inflammatory and nonmicrobial mechanisms. The high MMP levels are correlated with excessive corneal destruction in bacterial, herpetic, fungal, and acanthamoeba infections. Nonspecific treatments, such as tetracyclines, particularly doxycycline, or corticosteroids, are used as adjuvants to antimicrobials to alleviate the disproportionate degradation and inflammation of the corneal layers caused by corneal MMPs and decrease the recruitment and infiltration of inflammatory cells. Treatments showing inhibition of specific MMPs (Galardin, ZHAWOC7726), interfering with pro-MMP activation (EDTA, ascorbic acid), or showing anticytokine effect (epigallocatechin-2-gallate, TRAM-34) have been reported. Other treatments show a direct action over corneal collagen structure such as corneal cross-linking or have been associated with reduction of MMP levels such as amniotic membrane grafting. Although the use of these drugs has been shown in studies to be effective in controlling inflammation, especially in experimental ones, robust studies are still needed based on randomized and randomized clinical trials to demonstrate their potential effect as adjuvants in the management of infectious keratitis.

Immunoglobulin A levels and its correlation with neutrophil-to-lymphocyte ratio as inflammatory biomarkers for dry eye disease in type 2 diabetes: a retrospective study

Background

The neutrophil-to-lymphocyte ratio (NLR) and immunoglobulin A (IgA) level are commonly used as biomarkers for inflammation. Patients with type 2 diabetes (T2D) may experience an imbalance of tear film and inflammation, which can result in dry eye disease (DED). This study aimed to assess the levels of IgA and explore its correlation with the NLR as potential inflammatory biomarkers for dry eye disease in patients with T2D.

Methods

A retrospective study was conducted at the cornea clinic and diabetes centre of King Abdulaziz Medical City (Jeddah, Saudi Arabia). The study included patients with DED and the number of available T2D-DED patients determined the sample size. Neutrophil, lymphocyte, IgA and CRP (C-reactive protein) laboratory values were obtained from medical records and correlational analyses were performed.

Results

The study included 85 patients with an average age of 54 ± 14.4 years for the DED group (n=32) and 62 ± 13.9 years for the T2D-DED group (n=53). The age difference between the two groups was statistically significant (p 0.0001). The NLR values of the T2D-DED and DED groups were 3.203 ± 0.66 and 2.406 ± 0.46, respectively, with no significant difference (p<0.285). Similarly, there were no significant differences in neutrophil and lymphocyte values between the two groups. The IgA levels showed no significant variation between T2D-DED and DED groups (p<0.364). Spearman's correlation analysis in the DED group showed a significant negative correlation between IgA and lymphocyte (p=0.011; r= - 0.471) values and significant positive correlations between IgA and neutrophil (p=0.014; r=0.309) and NLR (p=0.052; r= - 0.283) values. In the T2D-DED group, a significant correlation was found between IgA and CRP values (p=0.032; r=0.33).

Conclusion

Although diabetic patients may exhibit higher levels of NLR and IgA that correlate with disease severity, our study did not find significant differences in NLR and IgA values between the two groups. These findings may guide future research and enhance understanding of the disease's underlying mechanisms.

NLRP3 Inflammasome as a Potential Therapeutic Target in Dry Eye Disease

Dry eye disease (DED) is a multifactorial ocular surface disorder arising from numerous interrelated underlying pathologies that trigger a self-perpetuating cycle of instability, hyperosmolarity, and ocular surface damage. Associated ocular discomfort and visual disturbance contribute negatively to quality of life. Ocular surface inflammation has been increasingly recognised as playing a key role in the pathophysiology of chronic DED. Current readily available anti-inflammatory agents successfully relieve symptoms, but often without addressing the underlying pathophysiological mechanism. The NOD-like receptor protein-3 (NLRP3) inflammasome pathway has recently been implicated as a key driver of ocular surface inflammation, as reported in pre-clinical and clinical studies of DED. This review discusses the intimate relationship between DED and inflammation, highlights the involvement of the inflammasome in the development of DED, describes existing anti-inflammatory therapies and their limitations, and evaluates the potential of the inflammasome in the context of the existing anti-inflammatory therapeutic landscape as a therapeutic target for effective treatment of the disease.

In Silico Identification of Natural Product-Based Inhibitors Targeting IL-1β/IL-1R Protein-Protein Interface

IL-1β mediates inflammation and regulates immune responses, cell proliferation, and differentiation. Dysregulation of IL-1β is linked to inflammatory and autoimmune diseases. Elevated IL-1β levels are found in patients with severe COVID-19, indicating its excessive production may worsen the disease. Also, dry eye disease patients show high IL-1β levels in tears and conjunctival epithelium. Therefore, IL-1β signaling is a potential therapeutic targeting for COVID-19 and aforementioned diseases. No small-molecule IL-1β inhibitor is clinically approved despite efforts. Developing such inhibitors is highly desirable. Herein, a docking-based strategy was used to screen the TCM (Traditional Chinese Medicine) database to identify possible IL-1β inhibitors with desirable pharmacological characteristics by targeting the IL-1β/IL-1R interface. Primarily, the docking-based screening was performed by selecting the crucial residues of IL-1β interface to retrieve the potential compounds. Afterwards, the compounds were shortlisted on the basis of binding scores and significant interactions with the crucial residues of IL-1β. Further, to gain insights into the dynamic behavior of the protein-ligand interactions, MD simulations were performed. The analysis suggests that four selected compounds were stabilized in an IL-1β pocket, possibly blocking the formation of an IL-1β/IL-1R complex. This indicates their potential to interfere with the immune response, making them potential therapeutic agents to investigate further.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

Dichotomous versus 5-scale grading system for the interpretation of the point-of-care immunoassay for tear matrix metalloproteinase-9 in dry eye

In this study, we compared the dichotomous and 5-scale grading systems for point-of-care immunoassay of tear matrix metalloproteinase (MMP)-9 in dry eye disease (DED) patients and identified the optimal dichotomous system to correlate with DED parameters. We included 167 DED patients without primary Sjogren's syndrome (pSS) (Non-SS DED) and 70 DED patients with pSS (SS DED). We graded MMP-9 expression in InflammaDry® (Quidel, San Diego, CA, USA) using a 5-scale grading system and dichotomous grading systems with four different cut-off grades (D1 to D4 systems). The only DED parameter that showed a significant correlation with the 5-scale grading method was tear osmolarity (Tosm). In both groups, subjects with positive MMP-9 had lower tear secretion and higher Tosm than those with negative MMP-9 according to the D2 dichotomous system. Tosm determined D2 positivity at cutoffs > 340.5 and > 317.5 mOsm/L in the Non-SS DED and SS DED groups, respectively. Tear secretion < 10.5 mm or tear break-up time < 5.5 s stratified D2 positivity in the Non-SS DED group. In conclusion, the dichotomous grading system of InflammaDry reflects ocular surface indices better than the 5-scale grading system and may be more practical in real clinical circumstances.

A Pilot Study of a Panel of Ocular Inflammation Biomarkers in Patients with Primary Sjögren’s Syndrome

Ocular diseases have a strong impact on individuals, the effects of which extend from milder visual impairment to blindness. Due to this and to their prevalence, these conditions constitute important health, social and economic challenges. Thus, improvements in their early detection and diagnosis will help dampen the impact of these conditions, both on patients and on healthcare systems alike. In this sense, identifying tear biomarkers could establish better non-invasive approaches to diagnose these diseases and to monitor responses to therapy. With this in mind, we developed a solid phase capture assay, based on antibody microarrays, to quantify S100A6, MMP-9 and CST4 in human tear samples, and we used these arrays to study tear samples from healthy controls and patients with Sjögren’s Syndrome, at times concomitant with rheumatoid arthritis. Our results point out that the detection of S100A6 in tear samples seems to be positively correlated to rheumatoid arthritis, consistent with the systemic nature of this autoinflammatory pathology. Thus, we provide evidence that antibody microarrays may potentially help diagnose certain pathologies, possibly paving the way for significant improvements in the future care of these patients.

Chondroitin sulfate and L-Cysteine conjugate modified cationic nanostructured lipid carriers: Pre-corneal retention, permeability, and related studies for dry eye treatment

In this study, a novel bioadhesive material, a conjugate of chondroitin sulfate and L-cysteine (CS-Cys), was synthesized and modified on the surface of the cationic nanostructured lipid carriers loaded dexamethasone to prepare a novel nano-lipid ocular delivery system (Dex-CS-Cys-cNLC). Through the permeation and retention studies of isolated cornea, it was demonstrated that Dex-CS-Cys-cNLC has better corneal permeation and retention ability and can better overcome the barrier effect of the ocular surface. In addition, the fluorescent probe (RhB) was used to replace the drug, and fluorescence imaging was used to investigate the ocular surface retention ability of the formulation, and the results showed that CS-Cys-cNLC has stronger retention ability and can effectively prolong the time of drug action in the ocular surface. Dex-CS-Cys-cNLC was not irritating to rabbit eye tissues and was a safe delivery system. The results of rabbit dry eye pharmacodynamic experiments also showed that Dex-CS-Cys-cNLC could effectively alleviate dry eye symptoms in rabbits, effectively repair corneal damage, and improve the stability of tear film. All these experimental results suggest that Dex-CS-Cys-cNLC is a promising drug delivery carrier for the treatment of anterior segment of the eye disease.

MAPK Pathways in Ocular Pathophysiology: Potential Therapeutic Drugs and Challenges

Mitogen-activated protein kinase (MAPK) pathways represent ubiquitous cellular signal transduction pathways that regulate all aspects of life and are frequently altered in disease. Once activated through phosphorylation, these MAPKs in turn phosphorylate and activate transcription factors present either in the cytoplasm or in the nucleus, leading to the expression of target genes and, as a consequence, they elicit various biological responses. The aim of this work is to provide a comprehensive review focusing on the roles of MAPK signaling pathways in ocular pathophysiology and the potential to influence these for the treatment of eye diseases. We summarize the current knowledge of identified MAPK-targeting compounds in the context of ocular diseases such as macular degeneration, cataract, glaucoma and keratopathy, but also in rare ocular diseases where the cell differentiation, proliferation or migration are defective. Potential therapeutic interventions are also discussed. Additionally, we discuss challenges in overcoming the reported eye toxicity of some MAPK inhibitors.

Prognostic significance of matrix metalloproteinase 9 in COMET operated chronic ocular Stevens-Johnson syndrome

PURPOSE

Molecular pathogenesis underlying persistent ocular surface inflammation in chronic Stevens-Johnson syndrome (SJS) still remains largely unexplored. The present study investigates the expression of matrix metalloproteinase 2 (MMP2), MMP3, MMP9, MMP11 and TIMP1 (tissue inhibittor of matrix metalloproteinase 1) in pannus tissues of chronic ocular SJS undergoing cultivated oral mucosal epithelial transplantation (COMET) and their prognostic relevance.

METHODS

In this prospective study, 45 eyes with chronic SJS underwent COMET for visual and anatomical rehabilitation. Preoperative and postoperative clinical parameters were documented. MMP2, MMP3, MMP9, MMP11 and TIMP1 expression were assessed using immunohistochemistry and quantitative real time PCR. Inflammadry MMP9 assay was performed at 1-year follow-up. Kaplan-Meier curves and Cox proportional hazard models were used to correlate protein expression with clinicopathological parameters and COMET graft survival outcomes.

RESULTS

MMP9 and MMP11 positivity was seen in both pannus epithelia (48% and 55%, respectively) and in stromal layer (57% and 33%, respectively) while MMP2 and MMP3 showed only pannus epithelial positivity in 35% and 51% cases, respectively. High MMP9 stromal expression was significantly associated with preoperative corneal keratinisation (p=0.011), conjunctival hyperaemia (p=0.014), symblepharon (p=0.028). High MMP9 and MMP3 epithelial expression were found to be independent risk factors for poor best-corrected visual acuity (BCVA) outcomes post-COMET (p=0.022 and p=0.048). Multivariate analysis revealed MMP9 to be the best prognostic marker (p=0.050).

CONCLUSION

Our findings suggest that differential expression of MMPs and TIMP1 is seen in SJS in chronic stage. Emergence of MMP9 as a poor prognostic predictor of BCVA post COMET and postoperative MMP9 immunoassay positivity could be a useful tool in further studies to understand the unresolved ocular surface inflammation seen in SJS.

The Effects of Fisetin on Cyclosporine-Treated Dry Eye Disease in Dogs

Dry eye disease (DED) is a chronic debilitating ophthalmological disease with the current therapeutic options focused on the suppression of the symptoms. Among the possibilities of how to improve DED therapy, polyphenols have shown an enormous capacity to counteract DED functional changes. The study aimed to specifically target pathophysiological mechanisms by the addition of fisetin to the cyclosporine treatment protocol. We examined dog patients with DED on cyclosporine treatment that were administered 0.1% fisetin or fisetin-free eye drops. For the assessment of fisetin effects, tear film production and matrix metalloproteinase 9 (MMP-9) were studied in the tear film. Tear production was not recovered after 7 or 14 days (9.40 mm ± 6.02 mm, p = 0.47; 9.80 mm ± 6.83 mm, p = 0.53, respectively). MMP-9 levels significantly increased after 7 days and then dropped after 14 days (775.44 ng/mL ± 527.52 ng/mL, p = 0.05; 328.49 ng/mL ± 376.29 ng/mL, p = 1.00, respectively). Fisetin addition to cyclosporine DED treatment was not able to restore tear fluid production but influenced molecular pathological events through MMP-9.

Modulation of ocular surface desiccation in a murine model by histatin-5 application

PURPOSE

To determine the efficacy of Histatin-5 (Hst5) peptide treatment in ameliorating dry eye disease (DED) phenotype in an in-vivo mouse model of scopolamine and desiccating stress (SDS) dry eye.

METHODS

SDS was induced in female C57BL/6 mice by subcutaneous injections of scopolamine hydrobromide and exposure to low relative humidity and forced air draft for five days. Mouse eyes were topically treated with synthetic Hst5 peptide or balanced salt solution (BSS) twice a day for four days. Control mice were not exposed to SDS induction and did not receive any treatments. Oregon green dextran (OGD) staining was used to evaluate corneal permeability. Histologically, staining with periodic acid schiff (PAS), immunohistochemistry (IHC) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), were used to quantify the number of goblet cells (GC), CD45+ immune cells and apoptotic cells respectively in formalin fixed paraffin embedded (FFPE) mouse whole eye sections.

RESULTS

Compared to treatment with BSS, Hst5 treatment significantly lowered corneal epithelial permeability, prevented conjunctival epithelial GC loss, decreased conjunctival CD45+ immune cell infiltration and reduced conjunctival epithelial cell apoptosis.

CONCLUSIONS

Hst5 peptide topical treatment significantly improves the clinical parameters observed in SDS experimental model of DED. This is the first report of the efficacy of Hst5 treatment of dry eye phenotype, and potential novel treatment for DED in the clinic. Hst5 represents a new class of efficacious therapeutic agents, demonstrating pro-epithelial and anti-inflammatory activities at the ocular surface.

Mechanisms of macular edema

Macular edema is the pathological accumulation of fluid in the central retina. It is a complication of many retinal diseases, including diabetic retinopathy, retinal vascular occlusions and uveitis, among others. Macular edema causes decreased visual acuity and, when chronic or refractory, can cause severe and permanent visual impairment and blindness. In most instances, it develops due to dysregulation of the blood-retinal barrier which permits infiltration of the retinal tissue by proteins and other solutes that are normally retained in the blood. The increase in osmotic pressure in the tissue drives fluid accumulation. Current treatments include vascular endothelial growth factor blockers, corticosteroids, and non-steroidal anti-inflammatory drugs. These treatments target vasoactive and inflammatory mediators that cause disruption to the blood-retinal barrier. In this review, a clinical overview of macular edema is provided, mechanisms of disease are discussed, highlighting processes targeted by current treatments, and areas of opportunity for future research are identified.

Kaempferol Inhibits Dry Eye-Related Corneal Inflammation In Vitro Via the p38 Pathway

ObjectiveThe purpose of this study is to investigate the effect of kaempferol (KAE), an effective constituent of Buddleja officinalis, on human corneal epithelial cells (HCECs) under a hyperosmolar environment. Methods HCECs were cultured in DMEM/F12 medium and allocated into four groups: normal, model, vehicle, and KAE. Ki67 staining was used to detect HCEC proliferation; TdT-mediated dUTP Nick-End Labeling staining was used to detect HCEC apoptosis; quantified real-time PCR was used to investigate the mRNA relative expression levels of TNF-α, IL-6, and p38. and Western blot was used to reveal the protein expression levels of TNF-α, IL-6, and p38. Results Compared with those in the normal group, the proliferation ability of HCECs was significantly inhibited and the apoptosis rate of HCECs was notably increased in the model group; but KAE could effectively improve HCEC proliferation and reduce HCEC apoptosis. Compared with those in the normal group, the mRNA relative expressions and protein levels of TNF-α, IL-6, and p38 were significantly increased in the model group, which were effectively decreased after KAE intervention. Conclusion KAE could promote HCEC proliferation and reduce cell apoptosis, as well as inhibit the expression of inflammatory factors in a hypertonic-induced HCEC model via the p38MAPK pathway.

Corneal Refractive Surgery Considerations in Patients with Cystic Fibrosis and Cystic Fibrosis Transmembrane Conductance Regulator-Related Disorders

This article discusses common ocular manifestations of cystic fibrosis (CF) and cystic fibrosis transmembrane conductance regulator-related disorders (CFTR-RD). A structured approach for assessing and treating patients with CF/CFTR-RD seeking corneal refractive surgery is proposed, as well as a novel surgical risk scoring system. We also report two patients with various manifestations of CFTR dysfunction who presented for refractive surgery and the outcomes of the procedures. Surgeons seeking to perform refractive surgery on patients with CF/CFTR-RD should be aware of mild to severe clinical manifestations of CFTR dysfunction. Specific systemic and ocular manifestations of CF include chronic obstructive pulmonary disease (COPD), bronchiectasis, recurrent pulmonary infections, CF-related diabetes and liver disease, pancreatic insufficiency, conjunctival xerosis, night blindness, meibomian gland dysfunction (MGD), and blepharitis. Corneal manifestations include dry eye disease (DED), punctate keratitis (PK), filamentary keratitis (FK), xerophthalmia, and decreased endothelial cell density and central corneal thickness. Utilization of the appropriate review of systems (ROS) and screening tests will assist in determining if the patient is a suitable candidate for refractive surgery, as CF/CFTR-RD can impact the health of the cornea. Collaboration with other medical professionals who care for these patients is encouraged to ensure that their CF/CFTR-RD symptoms are best controlled via systemic and other treatment options. This will assist in reducing the severity of their ocular manifestations before and after surgery.

Topical corticosteroids for dry eye

BACKGROUND

Dry eye disease (DED), arising from various etiologic factors, leads to tear film instability, ocular surface damage, and neurosensory changes. DED causes symptoms such as ocular dryness, burning, itching, pain, and visual impairment. Given their well-established anti-inflammatory effects, topical steroid preparations have been widely used as a short-term treatment option for DED. Because of potential risks of ocular hypertension, cataracts, and infections associated with the long-term use of topical steroids, published trials comparing the efficacy and safety of topical steroids (versus placebo) have mostly been of short duration (three to eight weeks).

OBJECTIVES

To evaluate the effectiveness and safety of topical corticosteroids compared with no treatment, placebo, other steroidal or non-steroidal therapies, or a combination of therapies for DED.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; 2021, Issue 8); Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Sciences database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), without restriction on language or year of publication. The date of the last search was 20 August 2021.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in which topical corticosteroids, alone or in combination with tobramycin, were compared with no treatment, artificial tears (AT), vehicles, AT plus tobramycin, or cyclosporine A (CsA).

DATA COLLECTION AND ANALYSIS

We applied standard Cochrane methodology.

MAIN RESULTS

We identified 22 RCTs conducted in the USA, Italy, Spain, China, South Korea, and India. These RCTs reported outcome data from a total of 4169 participants with DED.  Study characteristics and risk of bias All trials recruited adults aged 18 years or older, except one trial that enrolled children and adolescents aged between 3 and 14 years. Half of these trials involved predominantly female participants (median 79%, interquartile range [IQR] 76% to 80%). On average, each trial enrolled 86 participants (IQR 40 to 158). The treatment duration of topical steroids ranged between one week and three months; trial duration lasted between one week and six months. Eight trials were sponsored exclusively by industry, and four trials were co-sponsored by industry and institutional or governmental funds. We assessed the risk of bias of both subjective and objective outcomes using RoB 2, finding nearly half of the trials to be at high risk of bias associated with selective outcome reporting. Findings Of the 22 trials, 16 evaluated effects of topical steroids, alone or in combination with tobramycin, as compared with lubricants (AT, vehicle), AT plus tobramycin, or no treatment. Corticosteroids probably have a small to moderate effect on improving patient-reported symptoms by 0.29 standardized mean difference (SMD) (95% confidence interval [CI] 0.16 to 0.42) as compared with lubricants (moderate certainty evidence). Topical steroids also likely have a small to moderate effect on lowering corneal staining scores by 0.4 SMDs (95% CI 0.18 to 0.62) (moderate certainty evidence). However, steroids may increase tear film break-up time (TBUT) slightly (mean difference [MD] 0.70 s, 95% CI 0.06 to 1.34; low certainty evidence) but not tear osmolarity (MD 1.60 mOsm/kg, 95% CI -10.47 to 13.67; very low certainty evidence).  Six trials examined topical steroids, either alone or in combination with CsA, against CsA alone. Low certainty evidence indicates that steroid-based interventions may have a small to moderate effect on improving participants' symptoms (SMD -0.33, 95% CI -0.51 to -0.15), but little to no effect on corneal staining scores (SMD 0.05, 95% CI -0.25 to 0.35) as compared with CsA. The effect of topical steroids compared to CsA alone on TBUT (MD 0.37 s, 95% CI -0.13 to 0.87) or tear osmolarity (MD 5.80 mOsm/kg, 95% CI -0.94 to 12.54; loteprednol etabonate alone) is uncertain because the certainty of the evidence is low or very low. None of the included trials reported on quality of life scores. Adverse effects The evidence for adverse ocular effects of topical corticosteroids is very uncertain. Topical corticosteroids may increase participants' risk of intraocular pressure (IOP) elevation (risk ratio [RR] 5.96, 95% CI 1.30 to 27.38) as compared with lubricants. However, when compared with CsA, steroids alone or combined with CsA may decrease or increase IOP elevation (RR 1.45, 95% CI 0.25 to 8.33). It is also uncertain whether topical steroids may increase risk of cataract formation when compared with lubricants (RR 0.34, 95% CI 0.01 to 8.22), given the short-term use and study duration (four weeks or less) to observe longer-term adverse effects.  AUTHORS' CONCLUSIONS: Overall, the evidence for the specified review outcomes was of moderate to very low certainty, mostly due to high risk of bias associated with selective results reporting. For dry eye patients whose symptoms require anti-inflammatory control, topical corticosteroids probably provide small to moderate degrees of symptom relief beyond lubricants, and may provide small to moderate degrees of symptom relief beyond CsA. However, the current evidence is less certain about the effects of steroids on improved tear film quality or quantity. The available evidence is also very uncertain regarding the adverse effects of topical corticosteroids on IOP elevation or cataract formation or progression. Future trials should generate high certainty evidence to inform physicians and patients of the optimal treatment strategies with topical corticosteroids in terms of regimen (types, formulations, dosages), duration, and its time-dependent adverse profile.

Development of a Novel In Vitro Immuno-Competent Model of Dry Eye Disease and Its Use to Evaluate the Efficacy of an Ocular Surface Modulator

PURPOSE

To develop an in vitro model of severe immunocompetent-dry eye disease (ic-DED) and to investigate the mechanism of action of a T-lysial ocular surface modulator.

MATERIALS AND METHODS

The reconstructed human corneal epithelium (HCE) was exposed to dryness stimuli. THP-1 cell infiltration into HCE was monitored at 4 h and 24 h from T-lysial application by immunohistochemistry (CD14, CD86, AQP3) and molecular biology (AQP3, TLR4 and TNF-α).

RESULTS

A reduction of CD14, CD86 and AQP3 was observed after T-lysial treatment at 24 h. TLR4 was overexpressed in ic-DED model and downregulated by T-Lysial after 24 h. TNF-α expression was not modified.

CONCLUSION

The ic-DED model can be used to monitor the migration and differentiation of THP-1 into HCE. T-lysial was found to exert anti-inflammatory activity. This experimental model is a promising tool to study the crosstalk between epithelial and immune cells, providing new insights on the mechanisms of DED onset.

The Extracts of Dendrobium Alleviate Dry Eye Disease in Rat Model by Regulating Aquaporin Expression and MAPKs/NF-κB Signalling

Dry eye is one of the most common ocular surface diseases caused by tear film instability and ocular surface damage due to an abnormal quality or quantity of tears. Inflammatory factors can initiate relevant transduction signalling pathways and trigger the inflammatory cascade response, resulting in ocular surface inflammation. It has been shown that the active ingredients in Dendrobium, such as polysaccharides, alkaloids and phenols, have anti-inflammatory, anti-tumour and immunity-boosting effects, and Dendrobium officinale extract can improve glandular secretion function, increase salivary secretion and increase the expression level of water channel protein in salivary glands in patients with dry eye syndromes. We investigated the in vitro cytoprotective effect of Dendrobium extracts in sodium chloride induced hyperosmotic conditions in human cornea keratocytes (HKs). Results showed that Dendrobium officinale Kimura et Migo water extract (DOW) and Dendrobium loddigesii Rolfe water extract (DLW) could upregulate the expression of aquaporins (AQP)5 protein, thus exerting a repairing effect by promoting cell migration. Furthermore, oral administration of DOW and DLW enhanced tear production in rats and exerted a protective effect on ocular surface damage. DOW and DLW could upregulate the expression of AQP5 and mucin (muc)5ac proteins in the lacrimal gland and reduce the inflammatory response. DOW and DLW inhibited the activation of the corresponding mitogen-activated protein kinases (MAPK) and NF-KB pathway, thereby playing a role in improving dry eye symptoms. This study provides a new perspective on dry eye treatment, and DOW and DLW may be potential therapeutic agents for dry eye.

Proteases and Their Potential Role as Biomarkers and Drug Targets in Dry Eye Disease and Ocular Surface Dysfunction

Dry eye disease (DED) is a multifactorial disorder that leads to ocular discomfort, visual disturbance, and tear film instability. DED is accompanied by an increase in tear osmolarity and ocular surface inflammation. The diagnosis and treatment of DED still present significant challenges. Therefore, novel biomarkers and treatments are of great interest. Proteases are present in different tissues on the ocular surface. In a healthy eye, proteases are highly regulated. However, dysregulation occurs in various pathologies, including DED. With this review, we provide an overview of the implications of different families of proteases in the development and severity of DED, along with studies involving protease inhibitors as potential therapeutic tools. Even though further research is needed, this review aims to give suggestions for identifying novel biomarkers and developing new protease inhibitors.

Efficacy and safety of manuka honey for dry eye

Dry eye has become an increasingly prevalent public health issue for which there is currently no cure. Manuka honey possesses anti-inflammatory and antioxidant properties that can be used to treat dry eye. The present study aimed to systematically review evidence supporting the treatment of dry eye with manuka honey and quantify this evidence via meta-analysis. Randomised clinical trials that fulfilled the inclusion criteria from database inception until 5 September 2021, were identified through online searches of seven databases, including but not limited to Embase, Medline, and Central. Changes between the point of longest follow-up and baseline subjective symptoms, tear film quality, ocular surface characteristics, adverse events, and compliance were selected for meta-analysis. A total of 288 adult participants with dry eye from five eligible randomised controlled trials were analysed. Compared with the control groups, treatment with manuka honey demonstrated a significant improvement in Ocular Surface Disease Index, Standard Patient Evaluation of Eye Dryness, tear evaporation rate, negative conversion rate of matrix metalloproteinase-9 levels, ocular surface staining, and daily use frequency of lubricant. No serious adverse events were reported, except for temporary stinging and redness, which were generally tolerated. This review found that manuka honey demonstrated promising results for the treatment of dry eye. However, limitations of the included studies and analytical methodology affect the reliability of this conclusion. Therefore, further high-quality randomised clinical trials are required to confirm the efficacy and safety of the use of manuka honey in the treatment of dry eye.

Ocular Surface Inflammatory Disorders (OSID): A Collective of Systemic Etiologies Which Cause or Amplify Dry Eye Syndrome

The ocular surface inflammatory disorders (OSID) are caused by systemic disorders that conduct a persistent inflammatory reaction in the ocular adnexal connective tissues, such as the conjunctiva, lacrimal gland (LG) and meibomian glands (MGs), which cause an inflammatory dry eye. The etiologies of OSID are a subset of systemic pathologies such as graft versus host disease, Sjögren’s syndrome, allergies, cicatrizing conjunctivitis, and more. These cause a purely inflammatory dry eye syndrome as a consequence of the persistent surrounding inflammation in the adnexal tissues, which is distinct from the age-related dry eye disease. A limitation toward management of these conditions is the lack of available biomarkers that can detect presence of inflammation and quantify damage on the conjunctiva and LG, even though these are considered to be drivers of the inflammatory milieu. The OSID and dry eye syndrome are caused by different immune cells which are not exclusively limited to T cell lymphocytes, but rather derive from an orchestrated multicellular immunologic response. Recognition of this syndrome is crucial to direct research in a direction that clarifies the potential role of inflammation and its associated immune phenotype on the conjunctiva and adnexal ocular tissues in OSID and dry eye syndrome. On this paper, we review the basic and clinical research evidence for the existence of OSID with focus on the different immune cells involved, the target tissues and potential consequences and OSIDs diagnostic and therapeutic implications.

Changes of Subjective Symptoms and Tear Film Biomarkers following Femto-LASIK

Femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) represents a common treatment modality in refractive surgery and shows excellent results in terms of safety, efficacy, predictability, and long-term stability. However, patients may be affected by dry eye symptoms. The aim of this study was to identify a potential association between subjective dry eye symptoms, objective dry eye markers, and possible changes in the tear film, which could be a target for future therapy development. Therefore, clinical (dry eye) examinations (OSDI, Schirmer test, lissamine green and fluorescein staining, BUT, visual acuity) were carried out before LASIK as well as 5 and 90 days post-OP. The dry eye marker MMP-9, cytokines (IL-1β, IL-8), and pain markers (NGF, CGRP) were quantified in tear samples with immunoassays. In addition, correlation analyses were performed. Clinical examinations revealed an upregulated OSDI score 5 days post-OP and an increased lissamine green staining score 90 days post-OP. Downregulated CGRP levels were noted 5 days post-OP, while other protein markers were not significantly altered after Femto-LASIK. Hence, Femto-LASIK surgery induced subjective symptoms like that of dry eye which could objectively rather be classified as Femto-LASIK-related discomfort. In the future, this could possibly be better detected and treated using pain markers such as CGRP.

Role of Caspase-1 as a Biomarker of Ocular Surface Damage

PURPOSE

To examine the potential of caspase-1 as a biomarker for ocular surface damage.

DESIGN

Cross-sectional study.

METHODS

A total of 113 tear samples (64 subjects) were analyzed. Sixty-one samples were from individuals with dry eye disease (DED), defined as Ocular Surface Disease Index (OSDI) ≥13 and/or corneal staining (CS) ≥3; 32 were from individuals who used glaucoma medication, irrespective of DED metrics; and 20 were from controls (CS <3 and OSDI <13). All individuals completed a medical history form and underwent an ocular surface assessment. Protein levels of caspase-1 were determined by enzyme-linked immunosorbent assay off Schirmer's strips. The primary analysis compared caspase-1 levels in individuals with signs of ocular surface damage (CS ≥3) in both case groups and controls. Secondary correlational analyses were conducted to examine relationships between caspase-1 levels and ocular signs and symptoms. Finally, area under the curve (AUC) analyses were performed to examine relationships between inflammatory markers and CS.

RESULTS

The mean age of the population was 58±18 years; 70% were female. Tear samples from individuals with ocular surface damage presented higher caspase-1 levels than the control group. Caspase-1 levels showed a moderate positive correlation with CS (Spearman r = 0.31; P = .001) and eye redness (Spearman r = 0.39; P = .004), and a negative correlation with Schirmer's (Spearman r = -0.46; P < .001) and tear break-up time (Spearman r = -0.33; P = .0006). Caspase-1 showed higher sensitivity and AUC for detecting ocular surface damage than InflammaDry, and its expression was not affected by anti-inflammatory agents.

CONCLUSION

Caspase-1 levels were higher in the tears of individuals with ocular surface damage, suggesting its potential to be used as a biomarker and/or therapeutic target.

Current trends in pharmaceutical treatment of Dry Eye Disease: A review

Dry eye disease (DED), keratoconjunctivitis sicca or dysfunctional tear syndrome, is the most prevalent ophthalmic disease which affects a substantial segment of people worldwide with increasing frequency. It is considered a multifactorial disease of the ocular surface and tear film, characterized by a variation of signs and symptoms. The symptoms range from mild to severe itching, burning, irritation, eye fatigue, and ocular inflammation that may lead to potential damage to the cornea, conjunctiva and even vision loss. Correspondingly, depending on the different manifestations and pathophysiology, the treatment must be tailored specifically to each patient by targeting the specific mechanisms implicated in their disease. Currently, there are several medical products and techniques available or under investigation for the treatment of DED. The present article focused on the pathophysiology of DED, the new diagnostic approach and the recently developed drug delivery systems or devices reducing the progress of the disease and treating the causes.

Porcine Corneas Incubated at Low Humidity Present Characteristic Features Found in Dry Eye Disease

Dry eye is a multifactorial disease that affects the ocular surface and tear fluid. Current treatment options include lubricant eye drop application several times a day. However, these eye drops often cause local side effects like ocular allergies or blurred vision after the application. To test new treatment options, a robust dry eye model is needed. Here, a porcine ex vivo model was established by means of incubation of porcine corneas in low humidity (LH) and characterized by histological damage evaluation, epithelial thickness and by relevant dry eye markers, such as interleukin 1 beta (IL-1β), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), occludin and galectin-3. In the dry eye model proposed, an increased secretion of IL-1β was observed, as well as an upregulation of NF-κB, occludin and galectin-3 mRNA expression. Moreover, the model presented a higher rate of cell death in comparison to the controls. These effects could be reversed with successful treatment of dexamethasone (dexa) and partially reversed with hyaluronic acid (HA) containing eye drops. Furthermore, medium-molecular-weight HA stimulated an increase in IL-1β in the model proposed. In conclusion, this dry eye model mimics the in vivo condition and hence allows for animal-free testing of novel dry eye treatments.

IGFBP-3 Regulates Mitochondrial Hyperfusion and Metabolic Activity in Ocular Surface Epithelia during Hyperosmolar Stress

In the eye, hyperosmolarity of the precorneal tear film triggers inflammation and the development of dry eye disease (DED), a highly prevalent condition that causes depression and disability in severe forms. A member of the insulin-like growth factor (IGF) family, the IGF binding protein-3 (IGFBP-3), is a pleiotropic protein with known roles in growth downregulation and survival. IGFBP-3 exerts these effects by blocking IGF-1 activation of the type 1 IGF-receptor (IGF-1R). Here, we examined a new IGF-independent role for IGFBP-3 in the regulation of mitochondrial and metabolic activity in ocular surface epithelial cells subject to hyperosmolar stress and in a mouse model of DED. We found that hyperosmolar stress decreased IGFBP-3 expression in vitro and in vivo. Treatment with exogenous IGFBP-3 induced an early, transient shift in IGF-1R to mitochondria, followed by IGFBP-3 nuclear accumulation. IGFBP-3 nuclear accumulation increased protein translation, blocked the hyperosmolar-mediated decrease in oxidative phosphorylation through the induction of mitochondrial hyperfusion, and restored corneal health in vivo. These data indicate that IGFBP-3 acts a stress response protein in ocular surface epithelia subject to hyperosmolar stress. These findings may lead to the development of first-in-class therapeutics to treat eye diseases with underlying mitochondrial dysfunction.

IL-17 Producing Lymphocytes Cause Dry Eye and Corneal Disease With Aging in RXRα Mutant Mouse

Purpose

To investigate IL-17 related mechanisms for developing dry eye disease in the Pinkie mouse strain with a loss of function RXRα mutation.

Methods

Measures of dry eye disease were assessed in the cornea and conjunctiva. Expression profiling was performed by single-cell RNA sequencing (scRNA-seq) to compare gene expression in conjunctival immune cells. Conjunctival immune cells were immunophenotyped by flow cytometry and confocal microscopy. The activity of RXRα ligand 9-cis retinoic acid (RA) was evaluated in cultured monocytes and γδ T cells.

Results

Compared to wild type (WT) C57BL/6, Pinkie has increased signs of dry eye disease, including decreased tear volume, corneal barrier disruption, corneal/conjunctival cornification and goblet cell loss, and corneal vascularization, opacification, and ulceration with aging. ScRNA-seq of conjunctival immune cells identified γδ T cells as the predominant IL-17 expressing population in both strains and there is a 4-fold increased percentage of γδ T cells in Pinkie. Compared to WT, IL-17a, and IL-17f significantly increased in Pinkie with conventional T cells and γδ T cells as the major producers. Flow cytometry revealed an increased number of IL-17⁺ γδ T cells in Pinkie. Tear concentration of the IL-17 inducer IL-23 is significantly higher in Pinkie. 9-cis RA treatment suppresses stimulated IL-17 production by γδ T and stimulatory activity of monocyte supernatant on γδ T cell IL-17 production. Compared to WT bone marrow chimeras, Pinkie chimeras have increased IL-17⁺ γδ T cells in the conjunctiva after desiccating stress and anti-IL-17 treatment suppresses dry eye induced corneal MMP-9 production/activity and conjunctival goblet cell loss.

Conclusion

These findings indicate that RXRα suppresses generation of dry eye disease-inducing IL-17 producing lymphocytes s in the conjunctiva and identifies RXRα as a potential therapeutic target in dry eye.

[Current and future effects of climate change on ophthalmology]

BACKGROUND AND OBJECTIVES

Climate change is also an increasingly important issue in the healthcare system. Due to its anatomical and physiological nature, the eye is directly exposed to environmental influences and changes in a special way.

METHODS

The current literature is used to illustrate the effects of climate-induced changes and the respective influences on the eye. A PubMed search (cut-off date 3 October 2021) using the search terms "climate change" or "planetary health" or "global health" and in each case "ophthalmology" or "eye" or "ocular" was used to determine the development of the number of publications between 2011 and 2021.

RESULTS

Measurable effects of climate change are already evident in a wide variety of ophthalmological fields. The significance of this topic, for instance, is reflected in a relatively constant increase in the number of publications and an almost tenfold increase in the number of publications per year from 2011 to 2021.

CONCLUSION

The impact of climate change on eye diseases and on the field of ophthalmology is multifaceted and could be expected to intensify in the coming years. Therefore, the interrelationships need to be further investigated in future studies, preferably on a large scale.

Impact of Incomplete Blinking Analyzed Using a Deep Learning Model With the Keratograph 5M in Dry Eye Disease

Purpose

To establish a deep learning model (DLM) for blink analysis, and investigate whether blink video frame sampling rate influences the accuracy of analysis.

Methods

This case-controlled study recruited 50 dry eye disease (DED) participants and 50 normal subjects. Blink videos recorded by a Keratograph 5M, symptom questionnaires, and ocular surface assessments were collected. After processing the blink images as datasets, further training and evaluation of DLM was performed. Blink videos of 30 frames per second (FPS) under white light, eight FPS extracted from white light videos, and eight FPS under infrared light were processed by DLM to generate blink profiles, allowing comparison of blink parameters, and their association with DED symptoms and signs.

Results

The blink parameters based on 30 FPS video presented higher sensitivity and accuracy than those based on eight FPS. The average relative interpalpebral height (IPH), the frequency and proportion of incomplete blinking (IB) were much higher in DED participants than in normal controls (P < 0.001). The IB frequency was closely associated with DED symptoms and signs (|R| ≥ 0.195, P ≤ 0.048), as was IB proportion and the average IPH (R ≥ 0.202, P ≤ 0.042).

Conclusions

DLM is a powerful tool for analyzing blink videos with high accuracy and sensitivity, and a frame rate ≥ 30 FPS is recommended. The IB frequency is indicative of DED.

Translational Relevance

The system of DLM-based blink analysis is of great potential for the assessment of IB and diagnosis of DED.

Protective Effect of Allyl Isothiocyanate in an Experimentally Induced Rat Model for Dry Eye Syndrome

PURPOSE/AIM OF THE STUDY

Growing evidence emphasizes the role of inflammation and oxidative stress in the pathogenesis of Dry Eye Syndrome (DES). Concordantly, the importance of agents targeting the inflammatory cascade and oxidative stress in the treatment is also progressively increasing. Herein, the study has investigated the protective effects and underlying mechanism of allyl isothiocyanate (AITC) on the ocular surface in a benzalkonium chloride (BAC)-induced dry eye rat model.

MATERIALS AND METHODS

A total of twenty-one Wistar albino rats were used to form the following three groups: Control, BAC, BAC + AITC. DES was established by topical application of BAC (four times daily for two weeks) in two groups, of which one group was treated with AITC (10 mg/kg BW daily oral dosage) for four weeks. Rats were monitored by dry eye diagnostic tests during the study period, and eventually, corneal tissues were used to evaluate for histopathologic analyzes and inflammatory and oxidative status.

RESULTS

A significant improvement was observed in various histopathologic and ophthalmologic findings, including tear volume, tear film integrity, ocular surface damage, ocular inflammatory signs, corneal thickness, and edema through AITC supplementation. AITC prominently balanced the inflammatory status and oxidative stress by lowering key proinflammatory mediators (NF-κB, TNF-α, IL-1β, IL-6, and IL-8) and increasing the activities of antioxidant enzymes (SOD, GSH-Px). Also, levels of protective tear proteins, including Muc1, Muc4, and Muc5 were recovered with AITC supplementation.

CONCLUSION

AITC alleviates clinical and histopathologic signs related to DES. Antioxidative and anti-inflammatory properties of AITC play a significant role in the mechanism of action.

Practical Guidance for the Use of Loteprednol Etabonate Ophthalmic Suspension 0.25% in the Management of Dry Eye Disease

Dry eye disease (DED) is a prevalent ocular surface disease. Like with any chronic disease, patients with DED can experience episodic flares. There are many existing and upcoming treatments for the chronic treatment of DED, yet treatments for DED flares are limited. Loteprednol etabonate 0.25% is an FDA approved treatment modality for the short-term treatment of the signs and symptoms of DED. This medication is formulated with the customized mucus-penetrating particle (MPP) technology, which has a greater ability to penetrate the ocular surface and more effectively deliver the active steroid to the ocular surface tissues as compared with conventional steroid preparations. There is also increasing utility of loteprednol etabonate 0.25% in the treatment of DED before and/or after cataract or refractive surgery or as induction therapy prior to starting chronic immunomodulatory medication for DED.