Multiplex cytokine levels of aqueous humor in acute primary angle-closure patients: fellow eye comparison

Interleukin-6 in retinal diseases: From pathogenesis to therapy

Interleukin-6 (IL-6) is a pleiotropic cytokine that participates in immunomodulation, inflammation, increases vascular permeability, hematopoiesis, and stimulates cell proliferation, among other biological processes. It exerts effects primarily through the classic and trans-signaling pathways. Many studies have demonstrated that IL-6 plays a critical role in the development of retinal diseases including diabetic retinopathy, uveitis, age-related macular degeneration, glaucoma, retinal vein occlusion, central serous chorioretinopathy and proliferative vitreoretinopathy. Thus, the progressive development of drugs targeting IL-6 and IL-6 receptor may play a role in the treatment of multiple retinal diseases. In this article, we comprehensively review the IL-6's biological functions of and its mechanisms in the pathogenesis of various retinal diseases. Furthermore, we summarize the drugs targeting IL-6 and its receptor and prospect their potential application in retinal diseases, hoping to provide new ideas for the treatment of retinal diseases.

The inflammatory cytokine profiles and ocular biometric characteristics of primary angle-closure glaucoma

OBJECTIVE

To investigate the pathogenesis of primary angle-closure disease (PACG) by measuring the anatomical structures of the anterior and posterior segments of the eye and inflammatory markers in the peripheral blood.

METHODS

This case-control study enrolled patients diagnosed with acute PACG (APACG) and chronic PACG (CPACG). It also enrolled control subjects without PACG. The anterior and posterior anatomical features were measured in all study participants. The levels of interleukin (IL)-6, tumour necrosis factor-α and the neutrophil-to-lymphocyte ratio (NLR) in the peripheral blood were measured.

RESULTS

This study analysed a total of 99 eyes: 34 eyes from 34 patients with APACG, 28 eyes from 28 patients with CPACG and 37 eyes from 37 control patients with senile cataract. The axis length, corneal diameter, anterior chamber depth and anterior chamber volume were significantly smaller in the APACG and CPACG groups compared with the controls. The level of IL-6 in the peripheral blood of patients with PACG was significantly lower than that of the controls. The NLR in the peripheral blood of patients with PACG was significantly greater than that of the controls.

CONCLUSIONS

Changes in the ocular anatomy and some inflammatory markers might be involved in the pathogenesis of PACG.

High Levels of Heat Shock Protein 47 in the Aqueous Humor of Patients with Acute Primary Angle Closure

INTRODUCTION

Acute primary angle closure (APAC) is often characterized by acute elevation of intraocular pressure accompanied by severe ocular and systemic symptoms. Excessive collagen accumulation, which can be caused by upregulated heat shock protein 47 (HSP47) expression, can produce scarring in rat conjunctival blebs. Meanwhile, the presence of HSP47 in human aqueous humor and its levels are yet to be determined.

METHODS

We examined 32 consecutive patients with APAC and 16 age-matched participants without APAC scheduled for cataract surgery who were enrolled as a control group. Aqueous humor samples were collected from all subjects at the time of surgery and compared between the subjects with and without APAC.

RESULTS

The levels of HSP47 in the aqueous humor of patients with APAC (1,210.4 ± 450.2 pg/mL) were found to be significantly increased (p = 0.001) compared with those in the control group (863.4 ± 240.0 pg/mL). Notably, the levels of HSP47 negatively correlated with the age of patients with APAC (p = 0.023).

CONCLUSION

HSP47 was upregulated in the aqueous humor of patients with APAC and may play a role in scarring after trabeculectomy for APAC.

Evaluations of aqueous humor protein markers in different types of glaucoma

To compare the concentrations of protein markers in aqueous humor (AH) of patients with primary open-angle glaucoma (POAG), chronic angle-closure glaucoma (CACG), acute primary angle closure (APAC), and cataract without glaucoma as the control group. AH samples were collected at the beginning of surgery from 82 eyes of 82 patients who were divided into POAG (n = 23), CACG (n = 21), APAC (n = 19), and cataract groups (n = 19). The expression levels of interferon-gamma (IFN-γ), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-17A (IL-17A), lymphotoxin-alpha (LT-α), monocyte chemotactic protein-1 (MCP-1), matrix metalloproteinase-2 (MMP-2), brain derived neurotrophic factor (BDNF), basic fibroblast growth factor (bFGF), platelet-derived growth factor-AA (PDGF-AA), vascular endothelial growth factor (VEGF), tissue inhibitor of metalloproteinases-1 (TIMP-1), and tumor necrosis factor-alpha (TNF-α) in AH were detected using a microsphere-based immunoassay. The AH levels of TNF-α, MMP-2, MCP-1, IFN-γ, and TIMP-1 in the APAC and CACG groups were significantly higher than those in control eyes. Additionally, the AH levels of interleukin-6 (IL-6) and VEGF in the APAC group were significantly higher than those in the control group (CG). The interleukin-8 (IL-8) levels in patients with POAG were significantly higher than those in control eyes, whereas the LT-α levels were significantly lower than those in control eyes. IL-6 levels were significantly correlated with the coefficient of variation (CV), whereas IL-6 levels were significantly negatively correlated with the frequency of hexagonal cells (HEX) and corneal endothelial cell density (CD). The levels of TNF-α, MMP-2, MCP-1, IFN-γ, TIMP-1, IL-6, IL-8, VEGF, and LT-α were different among the three types of glaucoma. These different types of glaucoma may be caused by various pathogeneses, which opens avenues for further investigation into the pathogenesis of glaucoma and discoveries new targets and pathways for the treatment of glaucoma.

Contribution of Interleukin-17A to Retinal Degenerative Diseases

Retinal degenerative diseases are a leading cause of vision loss and blindness throughout the world, characterized by chronic and progressive loss of neurons and/or myelin. One of the common features of retinal degenerative diseases and central neurodegenerative diseases is chronic neuroinflammation. Interleukin-17A (IL-17A) is the cytokine most closely related to disease in its family. Accumulating evidence suggests that IL-17A plays a key role in human retinal degenerative diseases, including age-related macular degeneration, diabetic retinopathy and glaucoma. This review aims to provide an overview of the role of IL-17A participating in the pathogenesis of retinal degenerative diseases, which may open new avenues for potential therapeutic interventions.

Proinflammatory Cytokine Profile Differences between Primary Open-Angle and Pseudoexfoliative Glaucoma

INTRODUCTION

Few studies have investigated glaucoma biomarkers in aqueous humor and tear and have found elevations of proinflammatory cytokines in patients with primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PXG). In this study, we investigate differences in inflammatory cytokines between POAG and PXG patients to find specific disease biomarkers.

METHODS

For this purpose, tear and aqueous humor samples of 14 eyes with POAG and 15 eyes with PXG undergoing cataract surgery were immunoassayed for 27 proinflammatory cytokines. The concentrations of cytokines in tear and aqueous humor and their association with clinical variables were analyzed, correlated, and compared between the groups.

RESULTS

We found that the levels of three cytokines differed significantly in the aqueous humor of POAG and PXG patients: IL-12 and IL-13 were higher in the POAG group, while monocyte chemoattractant protein-1 (monocyte chemotactic and activating factor) was higher in the PXG group. The number of topical hypotensive medications was correlated with diminished levels of two cytokines (IL-7 and basic fibroblast growth factor) in aqueous humor in the POAG group and with diminished levels of IL-12 in tear in the PXG group.

CONCLUSION

We conclude that both POAG and PXG show elevated concentrations of proinflammatory cytokines in tear and aqueous humor that could be used as biomarkers for these types of glaucoma and that the concentrations in aqueous humor of three cytokines, IL-12, IL-13, and monocyte chemoattractant protein-1 (monocyte chemotactic and activating factor), could be used to differentiate POAG and PXG.

Sub internal limiting membrane hemorrhage followed by bilateral optic disc hemorrhage in Kikuchi-Fujimoto disease: a case report

Background

Kikuchi-Fujimoto disease (KFD) is a necrotizing lymphadenitis, and presents fever of unknown origin and cervical lymphadenopathy. Ocular complications are unusual in KFD. Here we report a case of sub internal limiting membrane (ILM) hemorrhage followed by bilateral optic disc hemorrhage in KFD.

Case presentation

A 16-year-old Japanese man perceived a sudden decrease of right vision 3 days after onset of fever with unknown origin and left cervical lymphadenopathy. At presentation, visual acuity (VA) of right eye was 0.05 in decimal chart (1.30: converted to logarithm of minimum angle of resolution: logMAR). Fundus photograph showed extensive sub-ILM hemorrhage in right eye, and optic disc hemorrhages in both eyes. Fluorescein angiography presented hypo- and hyperfluorescences in optic disc of right eye, and hyperfluorescence in the disc of left eye. To make a definitive diagnosis, cervical lymph node biopsy was performed, and KFD was diagnosed pathologically. Thereafter, fever, headache and the cervical lymphadenopathy disappeared spontaneously. The sub-ILM hemorrhage was drained into the vitreous cavity by neodymium:yttrium-aluminum-garnet laser (Nd: YAG) hyaloidotomy. VA recovered to 1.5 (− 0.18: logMAR VA) in right eye.

Conclusion

Sub-ILM hemorrhage and optic disc hemorrhage are a KFD-related ocular complication.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02106-y.

Multiplex protein analysis for the study of glaucoma

INTRODUCTION

Glaucoma, a leading cause of irreversible blindness in the world, is a chronic neurodegenerative disease of multifactorial origin. Extensive research is ongoing to better understand, prevent, and treat progressive degeneration of retinal ganglion cells in glaucoma. While experimental models of glaucoma and postmortem tissues of human donors are analyzed for pathophysiological comprehension and improved treatment of this blinding disease, clinical samples of intraocular biofluids and blood collected from glaucoma patients are analyzed to identify predictive, diagnostic, and prognostic biomarkers. Multiplexing techniques for protein analysis offer a valuable approach for translational glaucoma research.

AREAS COVERED

This review provides an overview of the increasing applications of multiplex protein analysis for glaucoma research and also highlights current research challenges in the field and expected solutions from emerging technological advances.

EXPERT OPINION

Analytical techniques for multiplex analysis of proteins can help uncover neurodegenerative processes for enhanced treatment of glaucoma and can help identify molecular biomarkers for improved clinical testing and monitoring of this complex disease. This evolving field and continuously growing availability of new technologies are expected to broaden the comprehension of this complex neurodegenerative disease and speed up the progress toward new therapeutics and personalized patient care to prevent blindness from glaucoma.

Immune responses to injury and their links to eye disease

The eye is regarded as an immune privileged site. Since the presence of a vasculature would impair vision, the vasculature of the eye is located outside of the central light path. As a result, many regions of the eye evolved mechanisms to deliver immune cells to sites of dysgenesis, injury, or in response to the many age-related pathologies. While the purpose of these immune responses is reparative or protective, cytokines released by immune cells compromise visual acuity by inducing inflammation and fibrosis. The response to traumatic or pathological injury is distinct in different regions of the eye. Age-related diseases impact both the anterior and posterior segment and lead to reduced quality of life and blindness. Here we focus attention on the role that inflammation and fibrosis play in the progression of age-related pathologies of the cornea and the lens as well as in glaucoma, the formation of epiretinal membranes, and in proliferative vitreoretinopathy.

Primary angle closure glaucoma is characterized by altered extracellular matrix homeostasis in the iris

PURPOSE

To characterize the proteome of the iris in primary angle closure glaucoma (PACG).

EXPERIMENTAL DESIGN

In this cross-sectional study, iris samples were obtained from surgical iridectomy of 48 adults with PACG and five normal controls. Peptides from iris were analysed using liquid chromatography-tandem mass spectrometry on an Orbitrap Q Exactive Plus mass spectrometer. Verification of proteins of interest was conducted using selected reaction monitoring on a triple quadrupole mass spectrometer. The main outcome was proteins with a log₂ two-fold difference in expression in iris between PACG and controls.

RESULTS

There were 3,446 non-redundant proteins identified in human iris, of which 416 proteins were upregulated and 251 proteins were downregulated in PACG compared with controls. Thirty-two upregulated proteins were either components of the extracellular matrix (ECM) (fibrillar collagens, EMILIN-2, fibrinogen, fibronectin, matrilin-2), matricellular proteins (thrombospondin-1), proteins involved in cell-matrix interactions (integrins, laminin, histidine-rich glycoprotein, paxillin), or protease inhibitors known to modulate ECM turnover (α-2 macroglobulin, tissue factor pathway inhibitor 2, papilin). Two giant proteins, titin and obscurin, were up- and down-regulated, respectively, in the iris in PACG compared with controls.

CONCLUSIONS AND CLINICAL RELEVANCE

This proteomic study shows that ECM composition and homeostasis are altered in the iris in PACG.

Tear Film Cytokine Profile of Patients With the Boston Keratoprosthesis Type 1: Comparing Patients With and Without Glaucoma

Purpose

Inflammatory cytokines are involved in glaucoma pathogenesis. The purpose is to compare cytokine levels in the tear film of Boston keratoprosthesis (KPro) patients with and without glaucoma, relative to controls, and correlate levels with clinical parameters.

Methods

This cross-sectional study enrolled 58 eyes (58 patients): 41 KPro eyes with glaucoma, 7 KPro eyes without glaucoma, and 10 healthy controls. Twenty-seven cytokines were measured by multiplex bead immunoassay. Intraocular pressure (IOP), cup-to-disk ratio (CDR), retinal nerve fiber layer, visual acuity, topical medications, and angle closure were assessed in all KPro eyes. Cytokine levels between groups were analyzed by nonparametric tests, and correlations with clinical parameters by Spearman's test.

Results

Levels of TNF-ɑ, IL-1β, FGF-basic, and IFN-ɣ were significantly higher in KPro with glaucoma compared to KPro without (P = 0.020; 0.008; 0.043; 0.018, respectively). KPro groups had similar characteristics and topical antibiotic/steroid regimen. Levels of IL-1Ra, IL-15, VEGF, and RANTES were significantly higher in KPro with glaucoma compared to controls (P < 0.001; = 0.034; < 0.001; = 0.001, respectively). IL-1β and IFN-ɣ levels were positively correlated with CDR (r = 0.309, P = 0.039 and r = 0.452, P = 0.006, respectively) and IOP (r = 0.292, P = 0.047 and r = 0.368, P = 0.023, respectively). TNF-α and FGF-basic levels were positively correlated with CDR (r = 0.348, P = 0.022 and r = 0.344, P = 0.021, respectively).

Conclusions

TNF-α, IL-1β, FGF-basic, IFN-ɣ are elevated in tears of KPro patients with glaucoma and correlate with CDR and IOP. These results show, for the first time in humans, concordance with documented elevations of TNF-α and IL-1β in the murine KPro model. Ocular surface inflammation may reflect inflammatory processes of KPro glaucoma.

The role of IL-6-174 G/C polymorphism and intraocular IL-6 levels in the pathogenesis of ocular diseases: a systematic review and meta-analysis

Interleukin-6 (IL-6) is one of the key regulators behind the inflammatory and pathological process associated with ophthalmic diseases. The role of IL-6-174 G/C polymorphism as well as intraocular IL-6 levels among various eye disease patients differ across studies and has not been systematically reviewed. Thus, this study aims to provide a summary to understand the relationship between IL-6 and ophthalmic disease. In total, 8,252 and 11,014 subjects for IL-6-174 G/C and intraocular levels of IL-6, respectively, were retrieved from PubMed, Scopus and Web of Science. No association was found between IL-6-174 G/C polymorphisms with ocular diseases. Subgroup analyses revealed a suggestive association between the GC genotype of IL-6-174 G/C with proliferative diabetic retinopathy (PDR). Further, the level of intraocular IL-6 among ocular disease patients in general was found to be higher than the control group [standardized mean difference (SMD) = 1.41, 95% confidence interval (CI) 1.24-1.58, P < 0.00001]. Closer examination through subgroup analyses yielded similar results in several ocular diseases. This study thus indicates that the IL-6-174 G/C polymorphism does not predispose patients to ocular disease, although the GC genotype is likely to be a genetic biomarker for PDR. Moreover, intraocular IL-6 concentrations are related to the specific manifestations of the ophthalmic diseases. Further studies with larger sample sizes are warranted to confirm this conclusion.

Discovery and clinical translation of novel glaucoma biomarkers

Glaucoma and other optic neuropathies are characterized by progressive dysfunction and loss of retinal ganglion cells and their axons. Given the high prevalence of glaucoma-related blindness and the availability of treatment options, improving the diagnosis and precise monitoring of progression in these conditions is paramount. Here we review recent progress in the development of novel biomarkers for glaucoma in the context of disease pathophysiology and we propose future steps for the field, including integration of exploratory biomarker outcomes into prospective therapeutic trials. We anticipate that, when validated, some of the novel glaucoma biomarkers discussed here will prove useful for clinical diagnosis and prediction of progression, as well as monitoring of clinical responses to standard and investigational therapies.

Lowered Decorin With Aberrant Extracellular Matrix Remodeling in Aqueous Humor and Tenon's Tissue From Primary Glaucoma Patients

Purpose

To evaluate the inflammatory cytokine, growth factors, extracellular matrix (ECM) remodeling genes, profibrotic and antifibrotic molecules in patients undergoing glaucoma filtration surgery (GFS). Additionally, the effect of preoperative antiglaucoma medications (AGMs) and postoperative bleb status were related to these parameters.

Methods

Tenon's tissue and aqueous humour (AH) were collected from 207 patients undergoing GFS with primary open-angle glaucoma (POAG) (n = 77), primary angle-closure glaucoma (PACG) (n = 62), and cataract controls (n = 68). Monocyte chemoattractant protein-1 (MCP-1), connective tissue growth factor (CTGF), transforming growth factor β1/2 (TGF-β1/2), lysyl oxidase (LOX), lysyl oxidase L2 (LOXL2), elastin (ELN), collagen type 1 α 1 (COL1A1), secreted protein acidic and rich in cysteine (SPARC), α-smooth muscle actin (α-SMA), and decorin (DCN) were determined in tenon's tissue by real-time PCR and in AH using ELISA.

Results

A significant increase was observed in the transcripts of MCP-1, TGF-β2, and SPARC in POAG and PACG (P < 0.05); CTGF, TGF-β1, LOX, LOXL2, ELN, COL1A1, and α-SMA in PACG (P < 0.05) compared with control. DCN transcript was significantly decreased in POAG and PACG (P < 0.05) compared with control. The protein levels of CTGF, TGF-β1/β2, ELN, SPARC, and LOXL2 was significantly elevated in POAG and PACG (P < 0.05); DCN was decreased (P < 0.05) compared with control. These parameters showed significant association with duration of preoperative AGMs and postoperative bleb status.

Conclusions

This study demonstrates increased expression of growth factors and ECM molecules, both at protein and transcript levels in GFS patients. A decreased DCN in AH seems striking, and if restored might have a therapeutic role in minimizing postoperative scarring to improve GFS outcome.

Characteristic Cytokine Profiles of Aqueous Humor in Glaucoma Secondary to Sturge-Weber Syndrome

Patients with Sturge-Weber syndrome (SWS) are susceptible to ocular complications, and among them, glaucoma is one of the most frequent forms. In current study, we utilized multiplex human cytokine antibody array to simultaneously measure the concentration of 40 cytokines in aqueous humor (AH) of patients with SWS-induced glaucoma (SG), or from patients with senile cataract as controls. Compared with the control group, levels of interleukin (IL)-12p40, macrophage inflammatory protein (MIP)-1d, tumor necrosis factor-alpha (TNF-a), IL-5, IL-7, interleukin-6 receptor (IL-6R), and B lymphocyte chemoattractant (BLC) in AH were significantly higher in SG group. Samples from SG patients displayed significantly lower levels of MIP-1b, IL-6, MIP-1a, and monocyte chemoattractant protein (MCP)-1 than controls. Further analysis showed that IL-7, MIP-1a, TNF-a were positively correlated with intraocular pressure (IOP) in patients with early-onset SG. Moreover, IL-12p40 was negatively correlated with age in patients with SG. These cytokines may make contributions to the immunopathogenesis or progression of glaucoma in patients with SWS.

Measuring Anterior Chamber Inflammation After Cataract Surgery: A Review of the Literature Focusing on the Correlation with Cystoid Macular Edema

Cystoid macular edema (CME) is an infrequent, though potentially visually impairing, complication after uneventful cataract surgery. Rupture of the blood-aqueous barrier, with leakage of serum proteins into the aqueous humour, is the main pathogenic factor. However, only a few studies investigated the potential correlation between anterior chamber (AC) inflammation and the risk of cystoid macular changes occurring after surgery. This review aims to identify evidence of a correlation between AC inflammation and the risk of pseudophakic CME. One hundred eighty-seven prospective trials investigating AC inflammation after uncomplicated cataract surgery were identified. Methods of analysis of AC inflammation and the frequency of macular changes were recorded. In the majority (51%) of the studies, inflammation was assessed by clinical grading, followed by laser flare and cell photometry (LFCP) (42%) and aqueous humour sample (4%). Few studies (4%) adopted a combined LFCP and aqueous sample or clinical grading analysis. Sixteen (9%) studies investigated AC inflammation and macular changes by OCT (7%) or fluorescein angiography (2%). Correlation between the amount of postoperative AC inflammation and frequency of CME was documented in 7 studies, not confirmed in 2 studies, and not examined in the other 7. LFCP, more than the other methods of analysis, correlated with the frequency of CME postoperatively. Investigation of the relationship between AC inflammation and the risk of CME changes requires the adoption of quantitative methods of analysis of the inflammatory response after surgery. For this purpose, due to the low level of inflammation in the AC after uncomplicated cataract surgery, LFCP, more than subjective clinical grading, seems a more sensitive and reproducible method of measurement. Inflammation assessment after cataract surgery has a potential role in predicting the risk of CME development and may help to titrate the duration and intensity of treatment in relation to the surgical inflammatory response.

Histone H2B induces retinal ganglion cell death through toll-like receptor 4 in the vitreous of acute primary angle closure patients

Acute primary angle closure (APAC) is a disease of ophthalmic urgency; lack of treatment can lead to blindness. Even after adequate treatment for APAC, subsequent elevated acute intraocular pressure induces severe neuronal damage which can result in secondary glaucomatous optic neuropathy (GON). Damage-associated molecular patterns (DAMPs) are released from damaged and dead neuronal cells, which induce secondary inflammatory changes and further tissue damage. Our hypothesis is that histone H2B (H2B), which is one of the DAMPs, is released from damaged cells in the development of GON after APAC treatment. Intravitreal injection of H2B induces neuronal cell death through toll-like receptor 4 (TLR4) expression, following the upregulation of inflammatory cytokine mRNAs and phosphorylation of mitogen activated protein kinases (MAPKs). Knockdown of TLR4 caused a reduction of H2B neurotoxicity in damaged cells through TLR4 signaling. Significantly increased H2B was observed in the vitreous cells of APAC patients. In addition, enhanced H2B protein correlated with decreased ganglion cell analysis and retinal ganglion cell (RGC) layer thinning, which indicates the effect of H2B on RGCs. Our data from clinical and animal studies show the involvement of H2B-TLR4 pathways in the development of GON after APAC treatment providing new insight for the mechanism of RGC degeneration.

[Autoimmunity and glaucoma]

In addition to the clinically most relevant risk factor for glaucoma, i.e., elevated intraocular pressure (IOP), there are other factors with high relevance for the disease. Changes in the autoimmune component of the immune system are of particular importance. Clinical studies have demonstrated alterations in different autoantibodies in glaucoma patients compared to healthy controls, some of which increase in abundance/have a raised titer, but also some which have a reduced titer. These changes have a distinct potential-not only as a tool for early glaucoma detection, but also as a therapeutic option due to the documented neuroprotective effects of some of these antibodies. Several antibodies displaying lower abundance in glaucoma patients, e.g., antibodies against 14-3-3 proteins, γ‑/α-synuclein, or also against glial fibrillary acidic protein (GFAP), show neuroprotective effects on retinal ganglion cells in vivo and in vitro. To assess the relevance of changes detected in the immune system of glaucoma patients, "‑omics-based" analyses of different ocular tissues are of particular importance alongside cell culture studies. In this manner, not only samples derived from experimental studies but also samples derived from glaucoma patients in even very small amounts (e. g., tears, aqueous humor, serum, or post-mortem retina) can be analyzed in detail in terms of protein and, in particular, antibody changes. Modern mass spectrometric proteomic characterization of relevant samples will deliver valuable information concerning the understanding of molecular disease mechanisms in the coming years, thus also improving diagnosis and treatment of glaucoma.

Comparative analysis of cytokine profiles of glaucomatous tears and aqueous humour reveals potential biomarkers for trabeculectomy complications

Glaucoma is a multifactorial neurodegenerative disease that causes impaired vision and, in advanced cases, blindness. The increasing prevalence of glaucoma due to an ageing population has necessitated the identification of suitable biomarkers for the early detection of the disease. Aqueous humour (AH) has been proposed as a source of biomarkers, but it can only be collected using a minor, yet invasive surgical intervention. Tears, however, are constantly available and can be collected any time via noninvasive methods. In order to examine the utility of tear as a surrogate for aqueous humour in biomarker development, we compared the levels of 27 cytokines and chemokines in paired samples of tear and aqueous humour using a Luminex multiplex immunobead-based technique. Significantly higher levels of cytokines in tear compared to aqueous humour were detected suggesting that tear and aqueous humour are not identical in terms of inflammation response. Furthermore, the levels of IFN-γ, GM-CSF and IL-5 in tear were significantly lower in patients who developed complications after one year, but no statistically significant changes in cytokine levels were observed in aqueous humour. These three molecules may have potential as predictive biomarkers for the appearance of late flap-related complications of trabeculectomy.

Meditation enhances brain oxygenation, upregulates BDNF and improves quality of life in patients with primary open angle glaucoma: A randomized controlled trial

BACKGROUND

Glaucoma (POAG) is a kind of neurodegenerative disease known to be closely associated with stress and adverse quality of life (QOL). Stress has also been shown to be involved in etiopathogenesis of primary open angle glaucoma (POAG). Complementary treatment in form of Meditation has been reported to improve QOL, brain oxygenation and decrease markers of stress. With this premise, a randomized controlled trial was carried out to assess the effect of Meditation on intraocular pressure, subjective QOL and objective markers of stress and brain oxygenation in patients with POAG.

METHODS

Sixty patients were randomized into intervention and control groups. Intervention group underwent 45 minutes of Meditation daily for 6 weeks in addition to standard medical treatment while controls received only standard medical treatment. Inclusion criteria were patients with POAG, age >45 years, best corrected visual acuity >6/60. Patients with other ocular co-morbid conditions contributing to vision loss, systemic diseases, patients already practicing meditation in any form were excluded. An assessment of IOP, brain oxygenation using functional near infrared spectroscopy (fNIRS), QOL (WHO-BREF QOL) and stress markers in serum (cortisol, β-endorphins, interleukin-6, brain derived neurotrophic factor (BDNF), reactive oxygen species) was made at baseline and at 6 weeks.

RESULTS

21 female and 39 male patients were enrolled with a mean age of 57.28±9.37 years. All parameters were comparable between two groups at baseline. At 6 weeks mean level of IOP decreased significantly in intervention group (15.9±1.8 mmHg to 14.4±1.21 mm Hg, p-value 0.0001) as compared to control group (15.7±1.4 mmHg to 15.65±1.41, p-value 0.41). fNIRS showed significant improvement in oxygenated hemoglobin change (ΔHbO) in intervention group in the prefrontal cortex (p-value <  0.0001) as compared to control group (p-value 0.52). WHO-BREF QOL score increased significantly in intervention group (86.6±6.16 to 93.3±5.66, p-value 0.0001) as compared to control (89±7.25 to 89.07±3.24, p-value 0.74).Mean serum cortisol decreased significantly in intervention group (497±46.37 ng/ml to 447±53.78 ng/ml, p-value 0.01) as compared to control group (519.75±24.5 to 522.58±26.63 ng/ml, p-value 0.64). Mean β-endorphin levels increased significantly (33±5.52pg/ml to 43.27pg/ml, p-value <  0.0001) as compared to control group (34.78±4.1pg/ml to 36.33pg±4.07pg/ml p-value 0.27). Interleukin-6 decreased significantly in intervention group (2.2±0.5 ng/ml to 1.35±0.32 ng/ml, p-value <  0.0001) as compared to control group (2.03±0.37 to 2.17±0.34 ng/ml p-value 0.25). BDNF increased significantly in intervention group (52.24±6.71 to 63.25±13.48 ng/ml p-value 0.004) as compared to control group (53.23±5.82 to 54.42±5.66 ng/ml p-value 0.54). ROS decreased significantly in intervention group (1596.19±179.14 to 1261±244.31 RLU/min/104 neutrophils p-value 0.0001) as compared to control group (1577.5±172.02 to 1662.5±84.75 RLU/min/104 neutrophils p-value 0.16).

CONCLUSIONS

A short term course of Meditation was associated with significant improvement in brain oxygenation and QOL along with a reduction in IOP and stress markers. Meditation may be a useful as an adjunct to standard treatment in patients with POAG and potentially decrease the risk of glaucoma progression.

Intraocular cytokine profile and autoimmune reactions in retinitis pigmentosa, age-related macular degeneration, glaucoma and cataract

Purpose

To analyse intraocular cytokine levels and prevalence of intraocular antiretinal antibodies (ARAs) in patients with retinitis pigmentosa (RP), age‐related macular degeneration (AMD), glaucoma and cataract, and correlate the results to clinical manifestations.

Methods

We collected intraocular fluid samples from patients with RP (n = 25), AMD (n = 12), glaucoma (n = 28) and cataract (n = 22), and serum samples paired with the intraocular fluids from patients with RP (N = 7) and cataract (n = 10). Interleukin (IL)‐1β, IL‐1ra, IL‐2, IL‐6, IL‐6rα, IL‐7, IL‐8, IL‐10, IL‐17A, IL‐23, thymus‐ and activation‐regulated chemokine (TARC), monocyte chemoattractant protein‐1 (MCP‐1), tumour necrosis factor‐alpha (TNF‐α), placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) were measured using a multiplex assay. Antiretinal antibodies (ARA) detection was performed by indirect immunofluorescence.

Results

Increasing age was associated with increasing levels of IL‐6, IL‐8, TNF‐α and VEGF. All patient groups exhibited distinct profiles of intraocular cytokines. Intraocular levels of IL‐8 were highest in patients with AMD and glaucoma. Cataract patients exhibited high intraocular levels of IL‐23. Intraocular levels of IL‐2, IL‐6, MCP‐1 and PlGF in RP patients exceeded the levels of serum, indicating intraocular production. Intraocular ARAs were found in only one patient with AMD.

Conclusion

Increased levels of inflammatory cytokines in intraocular fluid of patients with originally noninflammatory ocular diseases show that intraocular inflammation is involved in their pathogenesis of these entities. Moreover, we show that increasing age is associated with increasing levels of intraocular cytokines and conclude that future studies on intraocular mediators should be corrected for age of patients.

Inflammatory cytokine profiles in eyes with primary angle-closure glaucoma

Acute primary angle-closure (APAC) eyes show an early 'acute inflammatory' condition, while the inflammation condition has not been fully elucidated in the development of primary angle-closure glaucoma (PACG). To evaluate the roles of inflammatory cytokines in the pathogenesis of PACG, this cross-sectional study involved 40 eyes of 32 PACG patients who required trabeculectomy and 24 eyes of 24 patients who required cataract surgery. The aqueous humor samples were collected at the time of surgery. Fifteen inflammatory cytokines were detected using the multiplex bead immunoassay technique, and the clinical information was recorded for the correlation analysis. Eight of the 15 cytokines were all detectable in both groups, including granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-6, IL-8, monocyte chemotactic protein (MCP)-1, MCP-3, macrophage-derived chemokine (MDC), macrophage inflammatory protein (MIP)-1β, and vascular endothelial growth factor (VEGF). When compared with the cataract patients, the MCP-3, MDC, and VEGF levels were elevated in the PACG patients, while the MCP-1 and MIP-1β levels were decreased. However, the G-CSF, IL-6, and IL-8 levels were similar between the two groups. The MCP-1 concentration was elevated accordingly as the disease progressed in the PACG patients. Our results suggest the PACG eyes retained a 'mild inflammation' condition in the aqueous humor, and MCP-1 may play an important role in the progression of this disease.

Growth Factors, Oxidative Damage, and Inflammation in Exfoliation Syndrome

Exfoliation syndrome (XFS) produces deleterious ocular aging and has protean systemic manifestations. Local ocular production of TGFβ1 is of central importance in XFS. TGFβ1 appears to induce the expression of LOXL1 and the production of other extracellular matrix components which are known to be present in exfoliation material. Furthermore, results from several studies find that the aqueous humor of exfoliation glaucoma patients exhibits a decreased antioxidant defense and increased oxidative stress systems. Finally, studies show that the levels of interleukin-6 and interleukin-8 in the aqueous humor of XFS patients were 3-fold higher than in controls. Overall TGFβ1, as well as a prooxidative and proinflammatory environment seems to play an important role in XFS.

Characteristic Profiles of Inflammatory Cytokines in the Aqueous Humor of Glaucomatous Eyes

PURPOSE

To analyze cytokine profiles of the aqueous humor of eyes with primary open-angle glaucoma (POAG), neovascular glaucoma (NVG), and cataract (as controls).

METHODS

A multiplex bead assay was used to measure concentrations of 27 cytokines in aqueous humor samples from 54 eyes.

RESULTS

Detection rates were as follows: IL-7: NVG higher than POAG; IL-10: POAG lower than cataract or NVG; and GM-CSF: cataract higher than POAG or NVG. Concentrations were as follows: IL-8, IP-10, MCP-1, and MIP-1β: POAG and NVG higher than cataract; IL-9: POAG lower than NVG; IL-12: POAG lower than cataract or NVG; and VEGF: NVG higher than cataract or POAG and POAG lower than cataract. Further analysis showed that IL-8, IP-10, MCP-1, and MIP-1β were correlated with intraocular pressure and age.

CONCLUSIONS

The detection rates and levels of various cytokines had different patterns in POAG and NVG patients, suggesting distinctive alterations in the microenvironment in different types of glaucoma.

Interleukin-6 Deficiency Attenuates Retinal Ganglion Cell Axonopathy and Glaucoma-Related Vision Loss

The pleotropic cytokine interleukin-6 (IL-6) is implicated in retinal ganglion cell (RGC) survival and degeneration, including that associated with glaucoma. IL-6 protects RGCs from pressure-induced apoptosis in vitro. However, it is unknown how IL-6 impacts glaucomatous degeneration in vivo. To study how IL-6 influences glaucomatous RGC axonopathy, accompanying glial reactivity, and resultant deficits in visual function, we performed neural tracing, histological, and neurobehavioral assessments in wildtype (B6;129SF2/J; WT) and IL-6 knock-out mice (B6;129S2-IL6^tm1kopf/J; IL-6-/-) after 8 weeks of unilateral or bilateral microbead-induced glaucoma (microbead occlusion model). IOP increased by 20% following microbead injection in both genotypes (p < 0.05). However, deficits in wound healing at the site of corneal injection were noted. In WT mice, elevated IOP produced degenerating axon profiles and decreased axon density in the optic nerve by 15% (p < 0.01). In IL-6-/- mice, axon density in the optic nerve did not differ between microbead- and saline-injected mice (p > 0.05) and degenerating axon profiles were minimal. Preservation of RGC axons was reflected in visual function, where visual acuity decreased significantly in a time-dependent manner with microbead-induced IOP elevation in WT (p < 0.001), but not IL-6-/- mice (p > 0.05). Despite this preservation of RGC axons and visual acuity, both microbead-injected WT and IL-6-/- mice exhibited a 50% decrease in anterograde CTB transport to the superior colliculus, as compared to saline-injected controls (p < 0.01). Assessment of glial reactivity revealed no genotype- or IOP-dependent changes in retinal astrocytes. IOP elevation decreased microglia density and percent retinal area covered in WT mice (p < 0.05), while IL-6-/- mice exhibited only a decrease in density (p < 0.05). Together, our findings indicate that two defining features of RGC axonopathy—axon transport deficits and structural degeneration of axons—likely occur via independent mechanisms. Our data suggest that IL-6 is part of a mechanism that specifically leads to structural degeneration of axons. Furthermore, its absence is sufficient to prevent both structural degeneration of the optic nerve and vision loss. Overall, our work supports the proposition that functional deficits in axon transport represent a therapeutic window for RGC axonopathy and identify IL-6 signaling as a strong target for such a therapeutic.

Microarray-based analysis of gene expression profiles in peripheral blood of patients with acute primary angle closure

BACKGROUND

We investigated the expression of molecules in peripheral blood mononuclear cells (PBMCs) and plasma of patients with acute primary angle closure (APAC).

MATERIALS AND METHODS

Peripheral blood was collected from patients with APAC (n = 10) and age-matched controls (n = 5). The gene transcription profile was analyzed in PBMCs using microarrays and validated by real-time reverse transcription polymerase chain reaction (RT-PCR). The levels of secreted proteins were evaluated in plasma by ELISA.

RESULTS

347 gene transcripts were up-regulated by 2-fold or more, and 696 transcripts down-regulated 2-fold or more in PBMCs from patients compared to controls. The most highly up-regulated gene was thrombospondin-1 (TSP-1, 8.66-fold increase), and the most down-regulated gene was prostaglandin-endoperoxide synthase 2 (PTGS2, 9.09-fold decrease). Real-time RT-PCR assay confirmed the increase of TSP-1 and the decrease of PTGS2 in PBMCs of patients. ELISA revealed that the levels of TSP-1 and active transforming growth factor (TGF)-β1 that is activated by TSP-1 were elevated in plasma of patients, while the level of prostaglandin E2 (PGE2) that is converted by PTGS2 was reduced. The plasma level of TSP-1 was positively correlated with that of active TGF-β1.

CONCLUSIONS

Our data suggest that the molecular network including TSP-1, TGF-β1, and PGE2 might be involved in the pathogenesis of APAC and PACG.