Novel inflammatory cytokines (IL-36, 37, 38) in the aqueous humor from patients with chronic primary angle closure glaucoma

Potential Immune-Inflammatory Proteome Biomarkers for Guiding the Treatment of Patients with Primary Acute Angle-Closure Glaucoma Caused by COVID-19

Primary acute angle-closure glaucoma (PAACG) is a sight-threatening condition that can lead to blindness. With the increasing incidence of COVID-19, a multitude of people are experiencing acute vision loss and severe swelling of the eyes and head. These patients were then diagnosed with acute angle closure, with or without a history of PACG. However, the mechanism by which viral infection causes PACG has not been clarified. This is the first study to explore the specific inflammatory proteomic landscape in SARS-CoV-2-induced PAACG. The expression of 92 inflammation-related proteins in 19 aqueous humor samples from PAACGs or cataract patients was detected using the Olink Target 96 Inflammation Panel based on a highly sensitive and specific proximity extension assay technology. The results showed that 76 proteins were significantly more abundant in the PAACG group than in the cataract group. Notably, the top eight differentially expressed proteins were IL-8, MCP-1, TNFRSF9, DNER, CCL4, Flt3L, CXCL10, and CD40. Generally, immune markers are related to inflammation, macrophage activation, and viral infection, revealing the crucial role of macrophages in the occurrence of PAACGs caused by SARS-CoV-2.

Anterior segment features in neovascular glaucoma: An ultrasound biomicroscopy study

PURPOSES

To investigate the features of the anterior segment structures in neovascular glaucoma (NVG) and analyze its differences from primary angle-closure glaucoma (PACG).

METHODS

This study included patients who were first diagnosed with monocular NVG and PACG at the Affiliated Eye Hospital of Nanchang University during August 2019 to June 2022. Ultrasound biomicroscopy (UBM) was used to measure the anterior segment parameters of those eyes, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber area (ACA), iris area (IA), maximum iris thickness (ITMAX), middle iris thickness (ITMID), iris curvature (IC), lens vault (LV), angle opening distance (AOD500), trabecular iris angle (TIA500), trabecular-iris space area (TISA500) and peripheral anterior synechia (PAS) length.

RESULTS

In this study, paired samples t-test showed that IA [1.170(0.324) mm2], ITMAX [0.368(0.079) mm], ITMID [0.280(0.062) mm] and IC [0.147(0.037) mm] of NVG were smaller than F-NVG [2.058(0.195) mm2, 0.611(0.045) mm, 0.415(0.049) mm and 0.272(0.077) mm], the AOD500, TIA500, and TISA500 of NVG were also smaller than F-NVG. Independent samples t-test showed that ACD [2.349(0.350) mm] and ACA [16.326(3.547) mm2] of NVG were larger than PACG [1.971(0.240) mm, 12.030(1.860) mm2], but the IA [1.170(0.324) mm2], ITMAX [0.368(0.079) mm], ITMID [0.280(0.062) mm], IC [0.147(0.037) mm] and LV [0.436(0.172 mm)] were smaller than PACG [1.740(0.294) mm2, 0.548(0.084) mm, 0.404(0.065) mm, 0.283(0.060) mm and 0.737(0.196) mm]. Among the 16 patients with 360° angle-closure NVG, the PAS length was 0.834 (0.326) mm, which exceeded the Schwalbe line.

CONCLUSION

In NVG, the iris is atrophied, thinned, and straight, while the ACD is normal or slightly shallow. In 360° angle-closure NVG, the PAS length exceeds the Schwalbe line, presenting a pseudo angle phenomenon and a hockey stick sign. Notably, the anterior segment structure morphology of NVG exhibit differences from those of PACG.

Staphylococcus aureus-derived virulent phenol-soluble modulin α triggers alarmin release to drive IL-36-dependent corneal inflammation

Methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with keratitis produces substantial amounts of phenol-soluble modulin α (PSMα). However, the role of PSMα in S. aureus keratitis remains unclear. We observed that PSMα-producing and PSMα-deficient strains could infect the cornea in our experimental mouse keratitis model; however, only the PSMα-producing strain delayed epithelial wound healing and induced stromal inflammation. PSMα induced damage to the epithelium, the release of alarmins IL-1α and IL-36α, and the expression of inflammatory chemokines by resident corneal cells in the mouse corneal organ culture. The IL-36 (but not IL-1) receptor antagonist attenuated mouse keratitis induced by PSMα-containing bacterial culture supernatants, as well as by infection with PSMα-producing S. aureus, suggesting that the corneal inflammations were dependent on IL-36. Recombinant PSMα elicited IL-36-dependent corneal inflammation in mice. Thus, PSMα and the subsequently released IL-36 are critical factors triggering inflammation during S. aureus keratitis.

The occurrence of acute primary angle closure triggered, aggravated, and accelerated by COVID-19 infection: retrospective observational study

Introduction

The aim of this study is to demonstrate the relevance of primary acute angle closure (APAC) and COVID-19 infection, compare the demographic features and manifestations between COVID-19 positive and negative patients with APAC, and infer the underlying mechanism.

Methods

This study is based on all patients diagnosed with APAC at the glaucoma center of Eye, Ear, Nose and Throat Hospital of Fudan University (Fenyang road center) from 15th December 2022 to 11th January 2023. Totally 171 APAC cases were categorized into COVID-19 positive and negative group. Demographic features and final treatment level of the patients were compared between the two groups. Clinical manifestations, intraocular pressure, and anterior chamber configuration were also compared between the two groups.

Results

In the COVID-19 positive group, the number of cases with APAC onset spiked in 22nd December 2022, which coincided with the spike of COVID-19 antigen positive people. Compared to the COVID-19 negative group, COVID-19 positive APAC patients were younger with a lower percentage of APAC history. Additionally, more eyes of COVID-19 positive APAC patients showed keratic precipitates. COVID-19 positive eyes had significantly larger anterior chamber depth with a more dilated pupil. Therefore, COVID-19 infection could probably act as a triggering factor of APAC.

Discussion

The onset of APAC might be accelerated by COVID-19 infection for patients with younger age and milder anatomical configuration. Additionally, COVID-19 related APAC cases might have a more abrupt and fierce onset. Ophthalmic emergent services should not be neglected during the epidemic period.

The emerging role of IL-38 in diseases: A comprehensive review

INTRODUCTION

Interleukin-38 (IL-38) is a new type of anti-inflammatory cytokine, which is mainly expressed in the immunity-related organs and is involved in various diseases including cardiovascular and cerebrovascular diseases, lung diseases, viral infectious diseases and autoimmune diseases.

AIM

This review aims to detail the biological function, receptors and signaling of IL-38, which highlights its therapeutic potential in related diseases.

CONCLUSION

This article provides a comprehensive review of the association between interleukin-38 and related diseases, using interleukin-38 as a keyword and searching the relevant literature through Pubmed and Web of science up to July 2023.

Ankylosing spondylitis and glaucoma in European population: A Mendelian randomization study

Background

The relationship between ankylosing spondylitis (AS) and glaucoma in the European population remains unclear. In the present study, we applied a two-sample Mendelian randomization (MR) method to investigate their causal relationship.

Methods

MR analysis was conducted to validate the causal associations between AS with glaucoma using summary statistics from the genome-wide association studies of AS (9,069 cases and 13,578 control subjects) and glaucoma (8,591 cases and 210,201 control subjects). The inverse variance weighting method was performed to evaluate the causal relationship. The MR-Egger regression approach was applied to assess pleiotropy, while Cochran's Q test was used to analyze heterogeneity. Subgroup analysis was performed according to primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG).

Results

The results of the MR study reveal a risk-increasing causal relationship between AS and glaucoma among European populations (OR = 1.35, 95%CI = 1.16-1.57, P = 8.81 × 10^-5). Pleiotropy and heterogeneity were not found in our study. In the subgroup analysis, AS was also causal with POAG (OR = 1.48, 95%CI = 1.17-1.86, P = 8.80 × 10^-4) and PACG (OR = 1.91, 95%CI = 1.03-3.51, P = 3.88 × 10^-2).

Conclusion

The results of the MR analysis suggested a causal relationship between AS and glaucoma in the European population. Further studies are needed to identify the specific mechanism between these two diseases.

Association between plasma free fatty acid levels and primary angle-closure glaucoma based on a mass spectrometry metabolomics analysis

PURPOSE

To determine the association between plasma free fatty acid (FFA) levels and primary angle-closure glaucoma (PACG).

METHODS

Free fatty acid (FFA) levels in patients with PACG (n = 181) and people without glaucoma (n = 340) were compared. Twenty-two FFAs and six lipid classes were measured using metabolomics analysis. Odds ratio (OR) of these metabolites and their 95% confidence intervals (95%CI) for PACG were obtained by logistic regression. Stepwise forward selection was performed to identify FFAs that influenced PACG risk. Areas under the curve (AUC) were applied to assess the predictive performance. Spearman's rank correlation was used to assess the relationship between ocular parameters and FFAs.

RESULTS

Most FFAs in the PACG group were lower than those in the non-glaucoma group. Docosahexaenoic acid (DHA; OR for fourth quartile (Q4) vs. first quartile (Q1): 0.32 (0.16-0.66); per standard deviation (SD) increase: 0.64 (0.49-0.83); p for trend: 0.0007) and total saturated fatty acids (SFAs; OR for Q4 versus Q1: 0.27 (0.13-0.56); per SD increase: 0.65 (0.50-0.87); p for trend: 0.0004) were associated with decreased PACG risk. The AUC of the model that included DHA, total SFAs, demographic and ophthalmic factors increased from 0.8230 (0.7811-0.8649) to 0.8512 (0.8133-0.8891) (increased AUC: 0.0282 (0.0112-0.0453); p for increased AUC: 0.0012). Additionally, the cup-disc ratio had a weak negative correlation with DHA and total SFAs (DHA: r = -0.12085, p = 0.0065; total SFAs: r = -0.13318, p = 0.0024).

CONCLUSIONS

Decrease in FFA levels may be related to lipid peroxidation. Docosahexaenoic acid (DHA) and total SFAs may be screening indices for PACG patients.

Immunobiological Properties and Clinical Applications of Interleukin-38 for Immune-Mediated Disorders: A Systematic Review Study

Exponential growth in the usage of "cytokines" (as seroimmunobiomarkers) has facilitated more accurate prognosis, early diagnosis, novel, and efficient immunotherapeutics. Numerous studies have reported immunopathophysiological and immunopathological processes of interleukin-38 (IL-38). Therefore, in this systematic review article, the authors aimed to present an updated comprehensive overview on the immunobiological mechanisms, diagnostic, and immune gene-based therapeutic potentials of IL-38. According to our inclusion and exclusion criteria, a total of 216 articles were collected from several search engines and databases from the January 2012 to July 2021 time interval by using six main keywords. Physiologic or pathologic microenvironments, optimal dosage, and involved receptors affect the functionalities of IL-38. Alterations in serum levels of IL-38 play a major role in the immunopathogenesis of a wide array of immune-mediated disorders. IL-38 shows anti-inflammatory activities by reduction or inhibition of pro-inflammatory cytokines, supporting the therapeutic aspects of IL-38 in inflammatory autoimmune diseases. According to the importance of pre-clinical studies, it seems that manipulation of the immune system by immunomodulatory properties of IL-38 can increase the accuracy of diagnosis, and decipher optimal clinical outcomes. To promote our knowledge, more collaboration is highly recommended among laboratory scientists, internal/infectious diseases specialists, oncologists, immunologists, diseases-specific biomarkers scientists, and basic medical researchers.

Research Progress on the Mechanism of Natural Product Ingredients in the Treatment of Uveitis

Background

As the spectrum of ophthalmic diseases keeps changing, uveitis has gradually become one of the major blinding eye diseases in the world. In recent years, it has become a research hotspot to select effective components for uveitis treatment from natural drugs.

Methods

We searched PubMed and EMBASE databases for studies written in English as well as Chinese National Knowledge Infrastructure (CNKI), CQVIP, and Wan Fang database for studies written in Chinese (inception through 30 December 2020).

Results

Eight kinds of natural product ingredients were included in this article. They were found to not only regulate the expression of cytokines, proliferation, and differentiation of T help cells but also inhibit the damage of cytokines and inflammatory cells to uvea, blood aqueous barrier, and blood retinal barrier.

Conclusion

Natural product ingredients have their unique advantages in the treatment of uveitis. They have good anti-inflammatory effects without causing serious adverse reactions, which enables them to be promising choices for preventive and therapeutic strategy of uveitis.

Proteome Characterization of Glaucoma Aqueous Humor

Glaucoma is the leading cause of irreversible blindness worldwide. The proteome characterization of glaucoma is not clearly understood. A total of 175 subjects, including 57 primary acute angle-closure glaucoma (PAACG), 50 primary chronic angle-closure glaucoma (PCACG), 35 neovascular glaucoma (NVG), and 33 cataract patients, were enrolled and comparison proteomic analysis was provided. The samples were randomly divided into discovery group or validation group, whose aqueous humor proteome was analyzed by data-independent acquisition or by parallel reaction monitoring. The common proteome features of three types of glaucoma were immune response, lipid metabolism, and cell death. Three proteins, VTN, SERPIND1, and CD14, showed significant upregulation in glaucoma and could discriminate glaucoma from cataract. Mutual differential proteomic analysis of PAACG, PCACG, and NVG showed different proteome characterization of the three types of glaucoma. NVG was characterized with activated angiogenesis. PAACG was characterized with activation of inflammation response. SERPIND1 was discovered to play vital role in glaucoma occurrences, which is associated with eye transparency decrease and glucose metabolism. This study would provide insights in understanding proteome characterization of glaucoma and benefit the clinical application of AH proteome.

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Aqueous humor proteome of different glaucoma (PACG, NVG) was profiled.

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Potential protein biomarkers for glaucoma were proposed.

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Potential mechanism of glaucoma was described.

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SERPIND1 was discovered to have potential value for glaucoma diagnosis.

IL-37 As a Potential Biotherapeutics of Inflammatory Diseases

Interleukin-37 (IL-37) was discovered as a new member of pro-inflammatory IL-1 superfamily. However, further studies suggested that IL-37 plays a critical anti-inflammatory role in innate and adaptive immunity. IL-37 may suppress the inflammatory process via intracellular SMAD family member 3 (SMAD3) and extracellular IL-18 Receptor alpha (IL-18Rα) signaling pathway, respectively. Meanwhile, the abnormal expression of IL-37 was observed in immune-mediated inflammatory diseases, such as inflammatory bowel disease, rheumatoid arthritis, atherosclerosis, systemic lupus erythematosus, asthma, and multiple sclerosis, which suggest IL-37 is a potential therapeutic target for these diseases. In this review, we summarize the anti-inflammatory mechanism of IL-37 and discuss the critical roles of IL-37 in the pathogenesis of these diseases. Further studies are required to confirm the effectiveness of IL-37 as a novel target for these inflammatory diseases.

Biology of interleukin-38 and its role in chronic inflammatory diseases

Interleukin (IL)-38 is the tenth member of the IL-1 cytokine family. IL-38 shares high similarity with IL-36Ra and IL-1Ra and can bind to their receptors, thus exerting an anti-inflammatory effect. Despite the lack of a signal peptide, IL-38 can be released from several cell types, but its maturation process remains obscure. The role of IL-38 in numerous inflammatory diseases, especially in autoimmune diseases, has been extensively studied. In this review, we discuss the characteristics, biological functions and pathways of IL-38, as well as its role in several chronic inflammatory diseases. Better understanding the role of IL-38 will pave the way for clinical treatments in the near future.

Association Between 17-β-Estradiol and Interleukin-8 and Visual Field Progression in Postmenopausal Women with Primary Angle Closure Glaucoma

PURPOSE

To investigate an association between sex hormones and inflammatory cytokines, and to determine whether baseline 17-β-estradiol (E2) and interleukin-8 (IL-8) are associated with visual field (VF) progression in postmenopausal women with primary angle closure glaucoma (PACG).

DESIGN

A prospective cross-sectional and cohort study.

PARTICIPANTS

The cross-sectional study enrolled 200 postmenopausal women with PACG and 151 healthy postmenopausal women as normal control subjects. A total of 105 postmenopausal women with PACG were included and followed up for ≥2 years in the cohort study.

METHODS

All participants were evaluated for levels of baseline sex hormones (follicle-stimulating hormone, prolactin, progesterone, testosterone, luteinizing hormone, and E2) and inflammatory cytokines (IL-1, IL-2, IL-6, IL-8, IL-10, and C-reactive protein) and underwent VF examinations. The cross-sectional study was conducted to establish risk factors for postmenopausal women with PACG using logistic regression analysis. The cohort study was designed to identify factors that could be used to predict VF progression in postmenopausal women with PACG using multivariate Cox regression analyses. The main outcome measures included factors associated with VF progression over time.

RESULTS

Decreased E2 (odds ratio 0.88 [95% confidence interval {CI} 0.78-0.99], P = .007) and increased IL-8 (odds ratio 1.12 [95% CI 1.01-1.23], P < .001) levels were risk factors in postmenopausal women with PACG. A significant negative correlation was observed between IL-8 levels and E2 (r = -0.21, P = .02). Multivariable regression analyses revealed a significant correlation between E2 levels and visual field mean deviation (MD) (B = -0.16, P = .04 [95% CI -.09 to -.003) and between IL-8 levels and MD (B = 0.36, P < .001 [95% CI 0.01-0.02]). During follow-up, 48 (45.71%) patients showed VF progression. Lower baseline E2 (hazard ratio 0.85 [95% CI 0.82-0.88], P = .04) and higher baseline IL-8 levels (hazard ratio 1.01 [95% CI 1.00-1.02], P = .004) were associated with progression of glaucoma. Patients with lower E2 levels had a significantly higher rate of PACG progression (log-rank test P < .001), similar to those with higher IL-8 levels (log-rank test P = .04).

CONCLUSIONS

Decreased E2 and increased IL-8 levels at baseline are significant predictors of VF progression in postmenopausal women with PACG.

A new target for the treatment of inflammatory bowel disease: Interleukin-37

Interleukin (IL)-37 belongs to the IL-1 cytokine family. It has anti-inflammatory effects on numerous autoimmune diseases such as asthma, psoriasis, inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), multiple sclerosis (MS) and rheumatoid arthritis (RA). Mechanistically, IL-37 plays an anti-inflammatory role by regulating the expression of inflammatory factors in two ways: binding extracellular receptors IL-18R or transferring into the nucleus with Smad3. IBD is a kind of idiopathic intestinal inflammatory disease with unknown etiology and pathogenesis. Recent researches had proved that IL-37 is negatively involved in the pathogenesis and development of IBD. Among various inflammatory diseases, IL-37 has been shown to regulate inflammatory development by acting on various immune cells such as neutrophils, macrophages (Mϕ), dendritic cells (DCs), T cells and intestinal epithelial cells. This review summarizes the biological role of IL-37, and its immunoregulatory effects on the immune cells, especially anti-inflammatory function in both human and experimental models of IBD.

Insight into interleukin-37: The potential therapeutic target in allergic diseases

Allergic diseases are ubiquitous diseases with detrimental effects on the quality of life of people worldwide. Common allergic diseases include asthma, allergic rhinitis (AR) and allergic dermatitis (AD). Recently, studies have shown that interleukin (IL)-37, a novel cytokine in the IL-1 family, exhibits broad protective properties in various diseases, such as autoimmune diseases and cancer. IL-37 displays its anti-inflammatory effect on diseases by curbing innate and acquired immunity as well as inflammatory reactions. IL-37 functions by forming a complex with IL-18Rα and IL-1R8 extracellularly and can be translocated to the nucleus upon forming a complex with mothers against decapentaplegic homolog 3 (Smad3) intracellularly, thereby affecting gene transcription and signaling pathway activation. In addition, increasing evidence confirms that IL-37 expression is aberrant in asthma, AR and AD, which indicates that IL-37 may also play essential roles in allergic diseases. Furthermore, accumulating data obtained from recombinant IL-37 (rIL-37)-treated mice and from IL-37 transgenic (IL-37tg) mice suggest a protective role for IL-37. This review will detail the role of IL-37 in the occurrence and development of allergic diseases and discuss the potential of IL-37 as a therapeutic target in allergic diseases.

IL-38: A New Player in Inflammatory Autoimmune Disorders

Interleukin (IL)-38, a newly discovered IL-1 family cytokine, is expressed in several tissues and secreted by various cells. IL-38 has recently been reported to exert an anti-inflammatory function by binding to several receptors, including interleukin-36 receptor (IL-36R), interleukin-1 receptor accessory protein-like 1 (IL-1RAPL1), and interleukin-1 receptor 1 (IL-1R1) to block binding with other pro-inflammatory cytokines and inhibit subsequent signaling pathways; thereby regulating the differentiation and function of T cells, peripheral blood mononuclear cells, macrophages, and dendritic cells. Inflammatory autoimmune diseases, which are common immune-mediated inflammatory syndromes, are characterized by an imbalance between T helper cells (Ths), especially Th1s and Th17s, and regulatory T cells (Tregs). Recent findings have shown that abnormal expression of IL-38 in inflammatory autoimmune diseases, such as rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, primary Sjogren's syndrome, psoriasis, inflammatory bowel disease, hidradenitis suppurativa, ankylosing spondylitis, and glaucoma, involves Th1s, Th17s, and Tregs. In this review, the expression, regulation, and biological function of IL-38 are discussed, as are the roles of IL-38 in various inflammatory autoimmune disorders. Current data support that the IL-38/IL-36R and/or IL-38/IL-1RAPL1 axis primarily play an anti-inflammatory role in the development and resolution of inflammatory autoimmune diseases and indicate a possible therapeutic benefit of IL-38 in these diseases.