Current Advances in Mechanisms and Treatment of Dry Eye Disease: Toward Anti-inflammatory and Immunomodulatory Therapy and Traditional Chinese Medicine

Role of Chinese Medicine Monomers in Dry Eye Disease: Breaking the Vicious Cycle of Inflammation

Dry eye disease (DED) is a chronically inflammatory ocular surface disorder of unknown pathogenesis. Anti-inflammatory medications, artificial tears, autologous serum, and LipiFlow have been shown to be highly beneficial in alleviating symptoms. Nevertheless, these interventions often provide only short-term results and do not address the underlying problems of the disease. There is growing evidence that the risk of DED is associated with a vicious cycle of inflammation. This vicious cycle of inflammation is produced by the interaction of several factors, including tear film hyperosmolarity, tear film instability, inflammation, and apoptosis. Chinese medicine monomers, distinguished by their multicomponent and multitarget advantages, have been shown to help treat DED by modulating tear film status, and inhibiting inflammatory responses, and apoptosis, providing a new way of thinking of the management of DED in Chinese medicine.

Implications of nanotechnology for the treatment of Dry Eye Disease: Recent advances

Managing Dry Eye Disease (DED), a prevalent condition affecting the ocular surface, remains challenging despite advancements in diagnostics and therapies. Current treatments primarily involve lubricating eye drops and anti-inflammatory medications, which often require prolonged use and generally provide only symptomatic relief. The current study focuses on improving DED treatments through nano-drug delivery technologies and advanced formulations. These systems aim to address the limitations of conventional therapies by providing extended, targeted, and sustained drug release. The development of innovative nanomaterials offers improved precision, control, and customization for DED management. By enabling controlled and sustained drug release, these nano-drug delivery systems could offer longer-lasting relief, addressing the chronic nature of DED more effectively than current symptomatic therapies. Future research should focus on integrating multiple therapeutic agents within these systems to simultaneously target inflammation and tear film instability. This review examines the potential of nano-based materials for DED treatment, with a particular emphasis on lipid-based, polymer-based and polysaccharide-based systems.

Mesenchymal Stem Cell-Sourced Exosomes as Potentially Novel Remedies for Severe Dry Eye Disease

Severe dry eye disease (DED) is an inflammatory condition characterized by a lack of sufficient moisture or lubrication on the surface of the eye, significantly impacting the quality of life and visual function. Since detrimental immune response is crucially responsible for the development and aggravation of DED, therapeutic agents which modulate phenotype and function of eye-infiltrated inflammatory immune cells could be used for the treatment of severe DED. Due to their potent immunomodulatory properties, mesenchymal stem cells (MSCs) represent potentially new remedies for the treatment of inflammatory eye diseases. The majority of MSC-sourced bioactive factors are contained within MSC-derived exosomes (MSC-Exos), nano-sized extracellular vesicles which, due to their nanosize dimension and lipid envelope, easily by pass all biological barriers in the body and deliver their cargo directly into the target immune cells. MSC-Exos contain a variety of bioactive proteins (growth factors, immunoregulatory molecules, cytokines, and chemokines) lipids, and microRNAs (miRNAs) which affect viability, proliferation, phenotype, and function of eye-infiltrated immune cells. Accordingly, MSC-Exos may modulate the progression of inflammatory eye diseases, including DED. Therefore, in this review article, we summarized the current knowledge regarding molecular and cellular mechanisms which were responsible for trophic, anti-inflammatory, immunoregulatory, and regenerative properties of MSC-Exos in the treatment of severe DED. For this purpose, an extensive literature review was carried out in February 2024 across several databases (Medline, Embase, and Google Scholar), from 2000 to the present. Eligible studies delineated molecular and cellular mechanisms responsible for the MSC-Exos-based modulation of immune cell-driven eye inflammation in DED, and their findings were analyzed in this review. Results obtained in these studies demonstrated beneficial effects of MSC-Exos in the treatment of severe DED, paving the way for their future clinical use in ophthalmology. Trial Registration: ClinicalTrials.gov identifier: NCT04213248, NCT06475027, NCT06543667, NCT05738629.

Evaluation of traditional Chinese medicine tea bag TBDESJS in patients with Sjögren's syndrome and dry eye syndrome: A phase II pilot study

ETHNOPHARMACOLOGICAL RELEVANCE

Sjögren's syndrome (SJS) and dry eye syndrome (DES) are characterized by ocular dryness from inadequate tear production or excessive evaporation. To evaluate the effectiveness of TBDESJS (Chun-Yu-Ching-Hua-Yin, CYCHY), a TCM tea bag, in treating SJS and DES patients compared with healthy controls (NHC).

MATERIALS AND METHODS

This phase II pilot study included 100 participants (60 SJS, 30 DES, 10 NHC) across 8 weeks, assessing changes in Schirmer's test, OSDI, ESSPRI, PSQI, FIRST, and artificial tear usage, using repeated measurement ANOVA and Tukey's honestly significant difference (HSD) for analysis.

RESULTS

Total 97 subjects completed the trial, for the left eye (OS) of Schirmer's test, significant improvements at 4, and 8 weeks were observed in SJS (0.13 ± 0.43-5.77 ± 2.87, and 7.60 ± 4.84 mm) and DES (0.21 ± 0.41-6.21 ± 2.97, and 7.86 ± 3.47 mm) (all p < .001). For the right eye (OD), significant improvements were observed in SJS (0.13 ± 0.39-6.77 ± 4.53, and 8.79 ± 5.92 mm) and DES (0.34 ± 0.55-6.59 ± 2.50, and 8.24 ± 3.42 mm) (all p < .001). Secondary outcomes showed reduced the dryness of ESSPRI scores in SJS (6.37 ± 1.97-5.57 ± 1.79, p < .001) and DES (6.10 ± 1.97-5.28 ± 2.23, p < .05). PSQI global scores improved significantly in all groups at 8 weeks (p < .05). Artificial tear usage decreased in SJS (4.93 ± 2.45-1.00 ± 0.82 times/day), DES (4.47 ± 1.99-0.66 ± 0.67 times/day) (all p < .001). No serious adverse events in this study.

CONCLUSION

TBDESJS significantly improved tear production, ocular dryness, and sleep quality, indicating potential neural regulation, anti-inflammatory and immunomodulatory benefits. These findings advocate for TBDESJS (Chun-Yu-Ching-Hua-Yin, CYCHY)'s comprehensive therapeutic value in SJS and DES treatment, emphasizing the need for further research to understand long-term effects and mechanisms.

Molecular Mechanisms Responsible for Mesenchymal Stem Cell-Dependent Attenuation of Tear Hyperosmolarity and Immune Cell-Driven Inflammation in the Eyes of Patients with Dry Eye Disease

BACKGROUND

Dry eye disease (DED) is a chronic condition characterized by a decrease in tear production or an increase in tear evaporation, leading to inflammation and damage of the ocular surface. Dysfunction of ion channels, tear hyperosmolarity and immune cell-driven inflammation create a vicious circle responsible for the pathological changes in the eyes of DED patients. Mesenchymal stem cells (MSCs) are adult, rapidly proliferating stem cells that produce a large number of immunoregulatory, angiomodulatory, and growth factors that efficiently reduce tear hyperosmolarity-induced pathological changes, inhibit harmful immune response, and provide trophic support to the injured corneal and conjuctival epithelial cells, goblet cells and acinar cells in lacrimal glands of DED patients.

METHODS

An extensive research in the literature was implemented in order to elucidate the role of MSCs in the attenuation of tear hyperosmolarity and eye inflammation in patients suffering from DED.

RESULTS

Findings obtained in preclinical and pilot clinical studies demonstrated that MSCs reduced tear hyperomsolaity-induced pathological changes and suppressed immune cell-driven eye inflammation. Additionally, MSC-based therapy managed to successfully address the most severe DED-related conditions and complications.

CONCLUSIONS

MSCs should be considered as potentially new therapeutic agents for the treatment of severe DED.

Observational Clinical Investigation Evaluating an Ophthalmic Solution Containing Xanthan Gum and Low Concentration Desonide Phosphate in Dry Eye Disease Treatment

INTRODUCTION

Patients with dry eye disease (DED) complain of a multitude of symptoms that affect their visual function and quality of life (QoL). This clinical investigation assessed the performance, tolerance, and safety of a novel preservative-free ophthalmic solution containing xanthan gum 0.2% and desonide sodium phosphate 0.025%.

METHODS

This was an observational, prospective, multicentric, and post-market clinical investigation to assess the effect of three times a day instillation of the study formulation in patients suffering from DED. The primary objective was to achieve a 50% reduction in conjunctival hyperemia index as assessed with the OCULUS Keratograph after 1 month of treatment compared to baseline values. The secondary objectives included patient-reported outcomes, clinical performance, and safety.

RESULTS

Thirty patients were enrolled (21 women, 9 men) with a mean age of 61.10 ± 14.53 years. The instillation of the study formulation was associated with a significant reduction in redness scores after 1 month of treatment compared to baseline (mean - 0.51 ± 0.51; p ≤ 0.0001). Although the primary endpoint was not completely met, a 50% reduction in the conjunctival hyperemia index was achieved in 23% of the participants, and 77% showed a reduction of 26% of the same index. In addition, the ophthalmic solution significantly increased tear film break-up time, and a significant reduction of corneal and conjunctival staining with fluorescein was achieved. It also reduced DED symptoms and had a very good safety profile.

CONCLUSIONS

the study formulation produced a significant improvement in the signs, symptoms, and QoL of patients with mild to moderate DED with a good safety profile after 1 month of treatment.

A Standardized Extract of Green-Cotyledon Small Black Soybean (EYESOY®) Ameliorates Dry Eye Syndrome in an Animal Model

PURPOSE

Dry eye syndrome is a common ocular disease that causes morbidity, high healthcare burden, and decreased quality of life. In this study, we evaluated the beneficial effects of a standardized extract of small black soybean (EYESOY®) in a benzalkonium chloride (BAC)-induced murine model of dry eye.

METHODS

Experimental dry eye was induced by instillation of 0.02% BAC on the right eye of the Sprague-Dawley rats. Saline solution or EYESOY were administered orally every day for 8 weeks.

RESULTS

EYESOY significantly improved tear volume in the cornea compared with that in the BAC group. Moreover, EYESOY inhibited damage to the corneal epithelial cells and lacrimal glands by suppressing the oxidative and inflammatory responses in a mouse dry eye model. It also increased the goblet cell density and mucin integrity in the conjunctiva.

CONCLUSIONS

Our results suggest that EYESOY has the potential to alleviate dry eye syndrome.

Identification and verification of inflammatory biomarkers for primary Sjögren's syndrome

INTRODUCTION

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by inflammatory infiltration, and dysfunction of the salivary and lacrimal glands. This research aimed to explore the disease pathogenesis and improve the diagnosis and treatment of pSS by mining inflammation-associated biomarkers.

METHODS

Five pSS-related datasets were retrieved from the Gene Expression Omnibus (GEO) database. Inflammation-associated biomarkers were determined by the least absolute shrinkage and selection operator (LASSO) and support vector machines recursive feature elimination (SVM-RFE). Single sample gene set enrichment analysis (ssGSEA) was implemented to profile the infiltration levels of immune cells. Real-time quantitative PCR (RT-qPCR) verified the expression of biomarkers in clinical samples.

RESULTS

Four genes (LY6E, EIF2AK2, IL15, and CXCL10) were screened as inflammation-associated biomarkers in pSS, the predictive performance of which were determined among three pSS-related datasets (AUC > 0.7). Functional enrichment results suggested that the biomarkers were involved in immune and inflammation-related pathways. Immune infiltration analysis revealed that biomarkers were notably connected with type 2 T helper cells, regulatory T cells which were significantly expressed between pSS and control. TESTOSTERONE and CYCLOSPORINE were predicted to take effect by targeting CXCL10 and IL15 in pSS, respectively.

CONCLUSION

Four inflammation-associated biomarkers (LY6E, EIF2AK2, IL15, and CXCL10) were explored, and the underlying regulatory mechanisms and targeted drugs associated with these biomarkers were preliminarily investigated according to a series of bioinformatics methods based on the online datasets of pSS, which provided a reference for understanding the pathogenesis of pSS. Key Points • Inflammation-associated biomarkers (LY6E, EIF2AK2, IL15, and CXCL10) were firstly identified in Sjögren's syndrome based on LASSO and SVM-RFE analyses. • CXCL10, EIF2AK2 and LY6E were prominently positively correlated with immature B cells, while IL15 were significantly negatively correlated with memory B cells in Sjögren's syndrome. • LY6E, EIF2AK2, IL15, and CXCL10 were significantly more highly expressed in clinical Sjögren's syndrome samples compared to healthy control samples, which was consistent with the analysis results of the GEO database. •LY6E, EIF2AK2, IL15, and CXCL10 might be used as the biomarkers for the treatment and diagnosis of Sjögren's syndrome.

Correlation between gout and dry eye disease

BACKGROUND

Gout is a common form of inflammatory arthritis that can cause a number of serious complications. Complications are common in patients with gout and complicate their management and disease outcome. The recent literature has reported that an increasing number of gout patients are presenting with dry eye symptoms. However, until now, the link between gout and dry eye disease has not been clearly defined. (It is unclear whether the two conditions simply co-exist, whether there are common risk factors, or whether dry eye disease is a complication of gout.) METHODS: A thorough literature search was conducted in the PubMed database to summarize the most recent information on the correlation between gout and dry eye disease and to explore the potential relationship between the pathogenesis of the two. (Objective: Therefore, in this paper, we review the recent literature on the correlation between gout and dry eye disease and explore the potential association between the pathogenesis of both.) RESULTS: Studies in the last five years have shown a correlation between gout and dry eye, i.e., gout is associated with an increased risk of dry eye. The NLRP3-IL-1β signaling pathway may be a potential mechanism for the combination of gout and dry eye disease; factors such as high blood uric acid and xanthine oxidase activation in gout patients may aggravate the development of dry eye disease; reducing the use of visual display terminals; reducing or abstaining from alcohol consumption; and moderate coffee intake may effectively prevent gout and dry eye disease.

CONCLUSIONS

It is an undisputed fact that many gout patients present with dry eye manifestations that seriously affect the quality of life of gout patients, and early detection and treatment of dry eye in gout patients are crucial.

Current Advances in Regenerative Strategies for Dry Eye Diseases: A Comprehensive Review

Dry eye disease (DED) is an emerging health issue affecting millions of individuals annually. Ocular surface disorders, such as DED, are characterized by inflammation triggered by various factors. This condition can lead to tear deficiencies, resulting in the desiccation of the ocular surface, corneal ulceration/perforation, increased susceptibility to infections, and a higher risk of severe visual impairment and blindness. Currently, the clinical management of DED primarily relies on supportive and palliative measures, including the frequent and lifelong use of different lubricating agents. While some advancements like punctal plugs, non-steroidal anti-inflammatory drugs, and salivary gland autografts have been attempted, they have shown limited effectiveness. Recently, there have been promising developments in the treatment of DED, including biomaterials such as nano-systems, hydrogels, and contact lenses for drug delivery, cell-based therapies, biological approaches, and tissue-based regenerative therapy. This article specifically explores the different strategies reported so far for treating DED. The aim is to discuss their potential as long-term cures for DED while also considering the factors that limit their feasibility and effectiveness. These advancements offer hope for more effective and sustainable treatment options in the future.

Evaluation of Conventional and Hyaluronic Acid-Coated Thymoquinone Liposomes in an In Vitro Model of Dry Eye

Dry eye disease (DED) is a common ocular disorder characterized by an inadequate lubrication of the eye by tears leading to inflammation and the alteration of the ocular surface. Current treatments are often limited due to their side effects and ineffectiveness. Thymoquinone (TQ) is a natural compound present in the essential oil of Nigella sativa L., with anti-inflammatory and antioxidant activities. In this study, conventional and hyaluronic acid-coated liposomes were developed to improve TQ activity at ocular level. In the present study, the cytoprotective effects of TQ or TQ liposomes were assessed against oxidative and inflammatory processes in human corneal epithelial cells (HCE-2). Hyperosmolarity conditions (450 mOsm) were used as a model of DED. Interleukin-1β (IL-1β), Interleukin-6 (IL-6) and tumor necrosis factor (TNFα) were quantified by quantitative real-time polymerase chain reaction (RT-qPCR); COX-2 and Phospho-NF-κB p65 (p-p65) by Western blotting (WB). Moreover, the mitochondrial reactive oxygen species (mtROS) levels were measured by MitoSOX assay. The hyperosmotic treatment induced a significant increase of the proinflammatory genes and proteins expression that were significantly decreased in the liposomes-treated cells. The coincubation with hyaluronic acid-coated liposomes significantly reverted the increase of mtROS production, evidently stimulated by the hyperosmotic stress. Our data suggest that TQ-loaded liposomes have potential as a therapeutic agent in dry eye disease, improving the TQ efficacy.

The Potential Role of Regulated Cell Death in Dry Eye Diseases and Ocular Surface Dysfunction

The research on new treatments for dry eye diseases (DED) has exponentially grown over the past decades. The increased prevalence of dry eye conditions, particularly in the younger population, has received much attention. Therefore, it is of utmost importance to identify novel therapeutical targets. Regulated cell death (RCD) is an essential process to control the biological homeostasis of tissues and organisms. The identification of different mechanisms of RCD stimulated the research on their involvement in different human pathologies. Whereas apoptosis has been widely studied in DED and included in the DED vicious cycle, the role of RCD still needs to be completely elucidated. In this review, we will explore the potential roles of different types of RCD in DED and ocular surface dysfunction. Starting from the evidence of oxidative stress and inflammation in dry eye pathology, we will analyse the potential therapeutic applications of the following principal RCD mechanisms: ferroptosis, necroptosis, and pyroptosis.

Using Network Pharmacology and Molecular Docking to Explore the Mechanism of Qiju Dihuang Pill against Dry Eye Disease

Background

Dry eye disease (DED) is a multifactorial disease of the ocular surface, which affects the quality of life and work efficiency of affected patients. The traditional Chinese medicine formula Qiju Dihuang Pill (QJDHP) has a good therapeutic effect on DED. However, the pharmacological mechanism is not clear.

Objective

To explore the mechanism of QJDHP in the treatment of DED based on network pharmacology.

Method

The active components in QJDHP were screened in Traditional Chinese Medicine Systems Pharmacology (TCMSP), and putative molecular targets of QJDHP were identified using the SwissTargetPrediction database. DED-related targets were screened by GeneCards and OMIM. We established protein-protein interaction (PPI) and core targets and corresponding active compound network by Cytoscape to identify the core targets and main compounds of QJDHP against DED. DAVID database was utilized for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Molecular docking was used to evaluate the binding activity between key active compounds and core targets.

Results

The results of network pharmacology showed that 253 targets of QJDHP were related to DED. PPI network analysis showed the 18 core targets. The binding affinity of docking results ranged from -5.7 to -9.3 kcal/mol, indicating a good docking effect. The results of GO enrichment analysis showed that the mechanism of QJDHP in the treatment of DED mainly involved biological processes such as apoptosis, oxidative stress, response to estrogen, angiogenesis, and the regulation of transcription factors. KEGG analysis showed that QJDHP may be regulated by the TNF signaling pathway, Toll-like receptor signaling pathway, MAPK signaling pathway, and estrogen signaling pathway in the treatment of DED.

Conclusion

In this study, we demonstrated the multicomponent, multitarget, and multichannel action mechanism of QJDHP in the treatment of DED and provided a foundation for further drug development research.

Moxibustion with Walnut Shell Spectacles Could Improve the Objective Symptoms and Tear Film Stability of Patients with Dry Eye Disease: A Randomized Controlled Trial

Objectives

This study aims to evaluate the efficacy and acceptability of moxibustion with walnut shell spectacles in treating dry eye disease (DED) patients and to provide treatment options.

Methods

126 DED patients were randomly allocated into the moxibustion group (treated by moxibustion with walnut shell spectacles, 64 cases) and the artificial tears group (treated with sodium hyaluronate eye drops, 62 cases). Evaluate the changes in the ocular surface disease index (OSDI), the visual analogue scale (VAS) of ocular discomfort, the tear film break-up time (TBUT), corneal fluorescein staining (CFS), and the Schirmer I test during the trial at baseline and after 1-week, 2-week, 3-week, and 4-week treatment. Evaluate the OSDI scale and the ocular symptom VAS scale one month after the end of treatment.

Results

There were no significant differences in baseline characteristics between the two groups. For OSDI scores, the results showed that the efficacy of the moxibustion group was no less than that of the artificial tear group. For VAS of ocular discomfort, both groups significantly reduced their score compared with baseline, and for the moxibustion group, the decrease was more significant. For TBUT, FAS, and PPS, results showed that the efficacy of the moxibustion group was significant in both eyes after 4 weeks of treatment, but the right eye was in the artificial tear group. For CFS and Schirmer I test scores, there was no significant effect for both groups.

Conclusion

Moxibustion with walnut shell spectacles could improve the clinical symptoms and tear film stability of DED patients; however, it has no significant efficacy on improving corneal injury and tear secretion, just the same as sodium hyaluronate eye drops. Nevertheless, moxibustion with walnut shell spectacles may have better effects on the self-assessment of ocular discomfort than sodium hyaluronate eye drops.

Recent Advances and the Mechanism of Astaxanthin in Ophthalmological Diseases

Astaxanthin (AST) is a naturally occurring carotenoid that has strong antioxidant, anti-inflammatory, and antiapoptosis effects and is used for the prevention of cancer. There is growing evidence that AST has multiple protective effects against various eye diseases. This article reviews the function and the potential mechanism of AST in dry eye syndrome, keratitis, cataract, diabetic retinopathy, age-related macular degeneration, high intraocular pressure, and other ocular diseases. It provides a theoretical basis for the clinical application of AST as a potential nutraceutical.