Comparison of cytokine profiles in the aqueous humor of eyes with pseudoexfoliation syndrome and glaucoma

Evaluation of expression pattern of cellular miRNAs (let-7b, miR-29a, miR-126, miR-34a, miR-181a-5p) and IL-6, TNF-α, and TGF-β in patients with pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PEX) is a critical clinical and biological extracellular matrix systemic disorder. Despite the unknown nature of PEX etiopathogenesis, it is proven to be associated with various genes and factors. The present research focused on analyzing the expression of miR and inflammatory cytokines in PEX. Serum and aqueous humor (AH) were collected prior to cataract surgery or trabeculectomy from 99 participants (64 with PEX glaucoma, and 35 controls). Real-time PCR was used for assessing the expression pattern of some miRNAs namely let-7b, miR-29a, miR-126, miR-34a, and miR-181a-5p. ELISA was carried out to explore the transcription of some inflammatory cytokines such as TGF-β, TNF-α, and IL-6. The indication of our results was a significant enhancement in the expression of let-7, miR-34a, and miR-181a-5p in PEX in contrast to the control group. Notwithstanding a significant suppression in miR-29a, and miR-126 expression levels in PEX in contrast to the control group. Analysis of ROC curve revealed that miR-29a and miR-34a are able to act as useful markers in order to discriminate the PEX group from the PEX negative subjects which were determined as the control group. According to the results obtained, the mean levels of TGF-β, TNF-α, and IL-6 upregulated among PEX subjects in contrast to control samples. In conclusion, our findings indicated that the selected cytokines alongside the selected miRNAs could be introduced as a biomarker panel in the diagnosis of PEX.

New Biomarker Combination Related to Oxidative Stress and Inflammation in Primary Open-Angle Glaucoma

Glaucoma is a multifactorial neurodegenerative disease and the second leading cause of blindness. Detection of clinically relevant biomarkers would aid better diagnoses and monitoring during treatment. In glaucoma, the protein composition of aqueous humor (AH) is relevant for the discovery of biomarkers. This study analyzes AH protein concentrations of putative biomarkers in patients with primary open-angle glaucoma (POAG) compared to a control group. Biomarkers were selected from known oxidative-stress and inflammatory pathways. Osteopontin (OPN), matrix metalloproteinase 9 (MMP-9), tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), and interleukin-10 (IL-10) were measured using the ELISA technique. Thirty-two patients were recruited to the study, including sixteen control and sixteen glaucoma patients. The glaucoma group consisted of patients diagnosed with glaucoma. In both groups, the aqueous humor sample was obtained during cataract surgery. A significant increase in OPN, MMP-9, TNF-alpha, and IL-10 was observed in the POAG aqueous humor, compared to the control group (p < 0.05). Of note, the AH of POAG patients contained 5.6 ± 1.2-fold more OPN compared to that of control patients. Different expression profiles of oxidative stress-related and inflammatory biomarkers were observed between patients with POAG and controls. This confirms the reported involvement of inflammatory and oxidative stress pathways in POAG pathophysiology. In the future, several, targeted AH proteins may be used to generate a potential biomarker expression profile of this disease, aiding diagnoses and disease progression monitoring. This approach highlights the importance of biomarkers in the future. Biomarkers provide a way to measure disease progression and response to treatment. In the future, biomarkers will play a more critical role in the toolkit of ophthalmology healthcare professionals as the field moves towards personalized medicine and precision healthcare.

Aqueous Humor Cytokine Profile in Primary Congenital Glaucoma

BACKGROUND

Cytokine profile in patients with primary open-angle glaucoma (POAG) differs from that in healthy controls. Due to the different pathophysiological mechanisms involved in the genesis of primary congenital glaucoma (PCG) and POAG, it is possible that the cytokine profile could also differ. The main objective of this study was to compare the concentrations of cytokines in the aqueous humor of patients with PCG with those of POAG patients and a control group.

METHODS

A cross-sectional study was conducted. Aqueous humor samples were taken from PCG and POAG patients eligible for glaucoma or cataract surgery and from patients undergoing cataract surgery. Twenty-seven cytokines were analyzed using the Human Cytokine 27-Plex Immunoassay Kit (Bio-Rad Laboratories, Hercules, CA, USA).

RESULTS

A total of 107 subjects were included: patients with PCG (n = 19), patients with POAG (n = 54), and a control group (CG) of patients undergoing cataract surgery (n = 34). Most cytokines measured in aqueous humor in PCG presented decreased values compared with POAG and controls. A statistically significant difference was observed in IL-1ra, IL-2, IL-5, IL-7, IL-8, IL-10, IL-12, IL-15, IL-17A, Eotaxin, FGF basic, G-CSF, GM-CSF, IFN-γ, MIP-1α, PDGF-bb, MIP-1β, RANTES, TNF-α, and VEGF.

CONCLUSION

PCG patients have a cytokine profile in aqueous humor different from POAG patients and patients without glaucoma, characterized by lower concentrations of multiple cytokines.

TGF-β-3 Induces Different Effects from TGF-β-1 and -2 on Cellular Metabolism and the Spatial Properties of the Human Trabecular Meshwork Cells

To compare the effects among three TGF-β isoforms (TGF-β-1, TGF-β-2, and TGF-β-3) on the human trabecular meshwork (HTM), two-dimensional (2D) and three-dimensional (3D) cultures of commercially available certified immortalized HTM cells were used, and the following analyses were conducted: (1) trans-endothelial electrical resistance (TEER) and FITC dextran permeability measurements (2D); (2) a real-time cellular metabolic analysis (2D); (3) analysis of the physical property of the 3D HTM spheroids; and (4) an assessment of the gene expression levels of extracellular matrix (ECM) components (2D and 3D). All three TGF-β isoforms induced a significant increase in TEER values and a relative decrease in FITC dextran permeability in the 2D-cultured HTM cells, but these effects were the most potent in the case of TGF-β-3. The findings indicated that solutions containing 10 ng/mL of TGF-β-1, 5 ng/mL of TGF-β-2, and 1 ng/mL of TGF-β-3 had nearly comparable effects on TEER measurements. However, a real-time cellular metabolic analysis of the 2D-cultured HTM cells under these concentrations revealed that TGF-3-β induced quite different effects on the metabolic phenotype, with a decreased ATP-linked respiration, increased proton leakage, and decreased glycolytic capacity compared with TGF-β-1 and TGF-β-2. In addition, the concentrations of the three TGF-β isoforms also caused diverse effects on the physical properties of 3D HTM spheroids and the mRNA expression of ECMs and their modulators, in many of which, the effects of TGF-β-3 were markedly different from TGF-β-1 and TGF-β-2. The findings presented herein suggest that these diverse efficacies among the TGF-β isoforms, especially the unique action of TGF-β-3 toward HTM, may induce different effects within the pathogenesis of glaucoma.

Postoperative proliferative vitreoretinopathy development is linked to vitreal CXCL5 concentrations

The specific changes linked to de novo development of postoperative PVR have remained elusive and were the object of the underlying study. Vitreous fluid (VF) was obtained at the beginning of vitrectomy from 65 eyes that underwent vitrectomy for primary rhegmatogenous retinal detachment (RRD) without preoperative PVR. Eyes developing postoperative PVR within 6 months after re-attachment surgery were compared to those which did not regarding the preoperative concentrations of 43 cytokines and chemokines in the VF, using multiplex beads analysis. For all comparisons Holm’s correction was applied in order to control for multiple comparisons. Twelve out of 65 eyes (18.5%) developed PVR postoperatively. While 12 of the chemokines and cytokines presented concentration differences on a statistical level of p < 0.05 (CXCL5, CCL11, CCL24, CCL26, GM-CSF, IFN-γ, CCL8, CCL7, MIF, MIG/CXCL9, CCL19, and CCL25), CXCL5 was the only cytokine with sufficiently robust difference in its VF concentrations to achieve significance in eyes developing postoperative PVR compared to eyes without PVR. CXCL5 may represent a potent biomarker for the de novo development of postoperative PVR. In line with its pathophysiological role in the development of PVR, it might serve as a basis for the development of urgently needed preventive options.

Primary Human Trabecular Meshwork Model for Pseudoexfoliation

The lack of an animal model or an in vitro model limits experimental options for studying temporal molecular events in pseudoexfoliation syndrome (PXF), an age related fibrillopathy causing trabecular meshwork damage and glaucoma. Our goal was to create a workable in vitro model of PXF using primary human TM (HTM) cell lines simulating human disease. Primary HTM cells harvested from healthy donors (n = 3), were exposed to various concentrations (5 ng/mL, 10 ng/mL, 15 ng/mL) of transforming growth factor-beta1 (TGF-β1) for different time points. Morphological change of epithelial–mesenchymal transition (EMT) was analyzed by direct microscopic visualization and immunoblotting for EMT markers. Expression of pro-fibrotic markers were analyzed by quantitative RT-PCR and immunoblotting. Cell viability and death in treated cells was analyzed using FACS and MTT assay. Protein complex and amyloid aggregate formation was analyzed by Immunofluorescence of oligomer11 and amyloid beta fibrils. Effect of these changes with pharmacological inhibitors of canonical and non-canonical TGF pathway was done to analyze the pathway involved. The expression of pro-fibrotic markers was markedly upregulated at 10 ng/mL of TGF-β1 exposure at 48–72 h of exposure with associated EMT changes at the same time point. Protein aggregates were seen maximally at these time points that were found to be localized around the nucleus and in the extracellular matrix (ECM). EMT and pro-fibrotic expression was differentially regulated by different canonical and non-canonical pathways suggesting complex regulatory mechanisms. This in vitro model using HTM cells simulated the main characteristics of human disease in PXF like pro-fibrotic gene expression, EMT, and aggregate formation.

Cytokine and Growth Factor Analysis in Exfoliation Syndrome and Glaucoma

Purpose

We compared cytokines, chemokines, and growth factors in the aqueous humor (AH) of patients with exfoliation syndrome (XFS), with exfoliation glaucoma (XFG), with primary open angle glaucoma (POAG), and healthy controls.

Methods

AH samples were collected from 21 patients with XFS, 28 with XFG, 14 with POAG, and 17 healthy controls during routine cataract surgery. The protein levels of 21 cytokines and growth factors, together with TGF-β1, 2, and 3, were quantified using the multiplex immunoassay. The levels of each protein in the four groups were compared using the Kruskal-Wallis test.

Results

Among the 24 cytokines and growth factors, 16 were out of the detectable range in >50% of samples in at least one group; the remaining 8 cytokines and growth factors (IL-8, MIP-1α, fractalkine, Flt3 ligand, PDGF-AA, VEGF, TGF-β1, and TGF-β2) were included in the analysis. TGF-β1 and TGF-β2 levels were the highest in patients with XFG and those with POAG, respectively. Expression levels of the inflammatory chemokines IL-8, MIP-1α, and fractalkine, as well as levels of the immune cell growth factor Flt3 ligand, were significantly higher in the XFG group than in the other groups. The protein levels of PDGF-AA and VEGF were not significantly different among the 4 groups.

Conclusions

Both TGF-β1 and inflammatory cytokines were highly expressed in the AH of patients with XFG. Considering that the levels of these cytokines are increased by oxidative stress and that they regulate the extracellular matrix, they may also play a role in intraocular pressure elevation in XFG.

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.

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.

Candidate Glaucoma Biomarkers: From Proteins to Metabolites, and the Pitfalls to Clinical Applications

Glaucoma is an insidious group of eye diseases causing degeneration of the optic nerve, progressive loss of vision, and irreversible blindness. The number of people affected by glaucoma is estimated at 80 million in 2021, with 3.5% prevalence in people aged 40-80. The main biomarker and risk factor for the onset and progression of glaucoma is the elevation of intraocular pressure. However, when glaucoma is diagnosed, the level of retinal ganglion cell death usually amounts to 30-40%; hence, the urgent need for its early diagnosis. Molecular biomarkers of glaucoma, from proteins to metabolites, may be helpful as indicators of pathogenic processes observed during the disease's onset. The discovery of human glaucoma biomarkers is hampered by major limitations, including whether medications are influencing the expression of molecules in bodily fluids, or whether tests to validate glaucoma biomarker candidates should include human subjects with different types and stages of the disease, as well as patients with other ocular and neurodegenerative diseases. Moreover, the proper selection of the biofluid or tissue, as well as the analytical platform, should be mandatory. In this review, we have summarized current knowledge concerning proteomics- and metabolomics-based glaucoma biomarkers, with specificity to human eye tissue and fluid, as well the analytical approach and the main results obtained. The complex data published to date, which include at least 458 different molecules altered in human glaucoma, merit a new, integrative approach allowing for future diagnostic tests based on the absolute quantification of local and/or systemic biomarkers of glaucoma.

Role of MCP-1 and IL-8 in viral anterior uveitis, and contractility and fibrogenic activity of trabecular meshwork cells

The inflammatory chemokines, monocyte chemoattractant protein (MCP)-1 and IL-8, are produced by normal trabecular meshwork cells (TM) and elevated in the aqueous humor of primary open angle glaucoma (POAG) and hypertensive anterior uveitis associated with viral infection. However, their role in TM cells and aqueous humor outflow remains unclear. Here, we explored the possible involvement of MCP-1 and IL-8 in the physiology of TM cells in the context of aqueous outflow, and the viral anterior uveitis. We found that the stimulation of human TM cells with MCP-1 and IL-8 induced significant increase in the formation of actin stress fibers and focal adhesions, myosin light chain phosphorylation, and the contraction of TM cells. MCP-1 and IL-8 also demonstrated elevation of extracellular matrix proteins, and the migration of TM cells. When TM cells were infected with HSV-1 and CMV virus, there was a significant increase in cytoskeletal contraction and Rho-GTPase activation. Viral infection of TM cells revealed significantly increased expression of MCP-1 and IL-8. Taken together, these results indicate that MCP-1 and IL-8 induce TM cell contractibility, fibrogenic activity, and plasticity, which are presumed to increase resistance to aqueous outflow in viral anterior uveitis and POAG.

Correlation of NUCB2/Nesfatin-1 with Cytokine Levels in Primary Open-Angle Glaucoma

Purpose

Nesfatin-1 is produced in various tissues of the body including the hypothalamus. Neuroprotective properties of the neuropeptide hormone Nesfatin-1 were recently described. The aim of the study was to analyze the molecule Nesfatin-1 as a possible biomarker in POAG with neuroprotective properties pointing out the retinal-hypothalamic axis as target site in POAG and to obtain a molecular signature of cytokines in POAG as neuroinflammatory processes are a key factor of glaucoma development.

Methods

In this study, n=35 patients with moderate and advanced POAG (mean age 65.0y, IOP 13.9±3.0mmHg) and n=35 healthy controls (mean age 51.6y, IOP 14.3±2.7mmHg) were included. Clinical parameters including IOP, cup to disc ratio (CDR), glaucoma medication and retinal nerve fiber layer thickness (RNFL) were recorded. Plasma was collected for NUCB2/nesfatin-1 measurement using a Nesfatin-1 ELISA and for detection of 13 inflammatory cytokines using a multiplex bead-based immunoassay (MagPix). Multiple linear regression analysis was performed to adjust for confounding factors.

Results

Sex-independent or sex-dependent variables showed no significant differences in the Nesfatin-1 level (p>0.05). As a trend, an increase in NUCB2/nesfatin-1 in male glaucoma patients was found. Increased concentrations of 11 cytokines (GM-CSF, Interferon-γ, Interleukin-1β, IL-2, 4, 5, 6, 7, 10, 12 and TNF-α) were detected in POAG. The female glaucoma patients demonstrated elevated cytokine concentrations compared to male patients. NUCB2/nesfatin-1 showed a significant correlation to IL-2 and IL-13 levels in POAG. Stepwise multiple regression analysis showed no difference in NUCB2/nesfatin-1 level between POAG and healthy controls after adjusting for sex and age (all p>0.05).

Conclusion

As a trend, male POAG patients showed increased plasma NUCB2/nesfatin-1 levels. We further found inflammation as contributing factor to the pathogenesis of glaucoma, with a greater inflammatory response in women.

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.

Tear and aqueous humour cytokine profile in primary open-angle glaucoma

PURPOSE

To evaluate the concentrations of pro-inflammatory cytokines in tear and aqueous humour of patients with primary open-angle glaucoma (POAG), relative to healthy controls.

METHOD

Tear and aqueous humour samples were collected from 29 healthy controls and 27 POAG patients. Twenty-seven inflammatory cytokines were analysed: interleukin (IL)-1β, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL9, IL-10, IL-12, IL-13, IL-15, IL-17, eotaxin, fibroblast growth factor (FGF) basic, granulocyte colony-stimulating factor, granulocyte-monocyte colony-stimulating factor, interferon (IFN)-γ, interferon gamma-induced protein, monocyte chemo-attractant protein-1, macrophage inflammatory protein (MIP)-1α, MIP-1β, platelet-derived growth factor, regulated on activation normal T cell expressed and secreted, tumour necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF).

RESULTS

In tear samples of glaucoma patients, an increase in IL-4, IL-12, IL-15, FGF-basic and VEGF was observed, as well as a decrease in MIP-1a relative to the control group (p < 0.05). IL-5, IL-12, IL-15, IFN-γ and MIP-1a were significantly higher in aqueous humour of glaucoma eyes (p < 0.05). A poor correlation between cytokine levels in tear and aqueous humour was observed.

CONCLUSION

The different profiles of inflammatory marker expression of patients with POAG and healthy controls confirm the inflammatory activity of the pathology, indicating that some of them could be used as potential biomarkers of this disease.

The high expression of the pain-related inflammatory factors in the eyes of cataract patients infected with hepatitis B virus

In cataract surgery, it is often found that patients infected hepatitis B virus (HBV) are likely to suffer from more pain than other patients. In order to assess the inflammation status of the aqueous humor in the eyes of cataract patients infected with HBV. RayBio Human Inflammation Array was used to assay aqueous humor samples collected from 14 eyes of patients infected with HBV and 14 eyes of cataract patients without HBV infection (the controls) during the cataract surgery. RayBio Human Quantibody Cutom Array was adopted for the validation of the screened cytokines, with aqueous humor samples collected from 40 eyes of patients infected with HBV and 40 eyes of the controls. A pain questionnaire survey about the surgery was conducted in all patients after operation. The results of questionnaire showed that patients infected with HBV were more likely to have pain during operation. The Human Inflammation Array revealed that the expression levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor α (TNF-α) and tumor necrosis factor β (TNF-β) were very high in HBV infected patients and IL-1ra was much lower in patients infected with HBV (all, P < 0.05). In validation, the Human Quantibody Cutom Array revealed that the expression levels of MCP-1 and TNF-α were high in HBV infected patients with significant difference (all P < 0.05). These results revealed that pain-related inflammatory factors MCP-1 and TNF-α were increased in aqueous humor of cataract patients infected with HBV, which indicates that patients infected with HBV may be more prone to intraoperative pain.

Risks and Challenges in Interpreting Simultaneous Analyses of Multiple Cytokines

Purpose

To determine the inherent risks of handling results below the lowest detectable value in the analysis of multiple cytokines in the aqueous humor of patients with retinal diseases by comparing possible statistical strategies to lower the risk of mis interpretation or over interpretation of results. Furthermore, in analyzing multiple cytokines simultaneously, the challenge of multiple comparison arises.

Methods

The analyses were based on parallel testing of 43 cytokines in 58 aqueous humor samples from patients with macular hole or epiretinal membrane. Substitution of values below the detection limit with 0.1 ×, 0.5 ×, or 1.0× of the lowest level of quantitation was compared with handling as missing value. The impact of correction for multiple comparisons was assessed using the Holm correction.

Results

When comparing macular hole with epiretinal membrane, not substituting the missing data revealed a difference (P < 0.05) for five compared with wight cytokines after their substitution, indicating an increased risk for under-estimating group differences (type II error). Correcting for multiple comparisons revealed a relevant risk of over estimating group differences (type I error).

Conclusions

Physiologic cytokine concentrations in ocular fluids typically range at or below the lowest level of quantitation. Handling of results below this cutoff as missing leads to increased type II errors. Not correcting for multiple comparisons increases the risk of a type I error. Taken together, both harbor a systematic inherent risk of misinterpretation of the results.

Translational Relevance

Ignoring the inherent risks of data misinterpretation in analyses of ocular fluid samples may result in mis leading conclusions regarding their biological relevance.

Peripheral blood CD163(+) monocytes and soluble CD163 in dry and neovascular age-related macular degeneration

Macrophages are the main infiltrating immune cells in choroidal neovascularization (CNV), a hallmark of the human wet, or neovascular age-related macular degeneration (AMD). Due to their plasticity and ability to adapt to the local microenvironment in a tissue-dependent manner, macrophages display polar functional phenotypes characterized by their cell surface markers and their cytokine profiles. We found accumulation of hemoglobin-scavenging cluster of differentiation 163 (CD163)(+) macrophages in laser-induced CNV lesions and higher expression of CD163(+) monocytes in the peripheral blood on day 7 post injury in mice. In comparison, CD80(+) macrophages did not differ with laser-injury in young or aged mice and did not significantly change in the peripheral blood of CNV mice. We examined the percentages of CD163(+), CD206(+), and CD80(+) monocytes in the peripheral blood of patients with wet AMD, patients with dry AMD, and in age-matched individuals without AMD as controls. Percentages of peripheral blood CD163(+) monocytes in both dry AMD (P < .001) and wet AMD (P < .05) were higher than in age-matched non-AMD controls, while there was no difference between the groups in the percentages of peripheral CD206(+) and CD80(+) monocytes. Further, serum level of soluble CD163 (sCD163) was elevated only in patients with wet AMD (P < .05). An examination of 40 cytokine levels across the study groups revealed that anti-VEGF treated patients with wet AMD, who showed no exudative signs on the day of blood drawing had a cytokine profile that was similar to that of non-AMD individuals. These results indicate that CD163 could be further evaluated for its potential as a useful marker of disease activity in patients with neovascular AMD. Future studies will address the origin and potential mechanistic role of CD163(+) macrophages in wet AMD pathologies of angiogenesis and leakage of blood components.

The expression of cytokines in aqueous humor of high myopic patients with cataracts

Purpose

To analyze the expression of 440 human cytokines in aqueous humor of high myopic patients with cataracts.

Methods

Eighty-five patients with cataracts were recruited in this study. In the screening stage, the RayBio G-Series Human Cytokine Antibody Array 440 was used to assay the aqueous humor samples collected from nine high myopic patients with cataracts and eight non-myopic patients with cataracts right before the surgery. The array was further used for verification of the screened cytokines, with aqueous humor samples obtained from 34 eyes of high myopic patients with cataracts and 34 eyes of non-myopic patients with cataracts.

Results

Compared with the non-myopic patients with cataracts, the expression levels of decorin, receptor activator of NF-kB (RANK), angiopoietin-1 (ANG-1), C-X-C motif ligand 16 (CXCL16), β-inducible gene-h3 (bIG-H3), insulin-like growth factor-binding protein 2 (IGFBP-2), and interleukin-17B (IL-17B) were statistically significantly higher in high myopic patients with cataracts (all p<0.000114). The matrix metalloproteinase-2 (MMP-2) level also increased in the aqueous humor of high myopic patients with cataracts (p = 0.0034). The concentrations of ANG-1 and MMP-2 were also increased in the aqueous humor of the confirmatory stage (all p<0.05).

Conclusions

In this study, numerous cytokines in aqueous humor were detected in high myopic patients with cataracts and non-myopic patients with cataracts, and it was confirmed that the MMP-2 level in the aqueous humor of patients with high myopia was statistically significantly increased. Further verification also revealed the elevation of ANG-1 in the aqueous humor of high myopic patients with cataracts, which suggests that ANG-1 may be related to the pathogenesis of high myopia.

Chemokine IL-8 level in aqueous humor of open-angle glaucoma: A meta-analysis

OBJECTIVE

To estimate an accurate level of IL-8 in aqueous humor among open-angle glaucoma (OAG) patients.

METHODS

Meta-analysis was performed from available studies that investigated the IL-8 level in the aqueous humor of OAG patients and control subjects.

RESULTS

A total of 17 studies were selected. The pooled result showed that IL-8 levels in aqueous humor of patients with OAG were higher than in control subjects (SMD=0.98, 95% CI=0.68-1.27, p<0.00001).

CONCLUSION

This meta-analysis indicates that patients with OAG may have a higher aqueous humor IL-8 levels compared to control subjects, which supports the notion that IL-8 is one of the contributing factors in the development of OAG.

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.

Molecular Biology of Exfoliation Syndrome

Exfoliation syndrome (XFS) is a common age-related matrix process resulting from excessive production and disordered assembly of elastic microfibrillar components into highly cross-linked fibrillary aggregates throughout the anterior eye segment and various organ systems. The underlying molecular pathophysiology involves a complex interplay of profibrotic protagonists including growth factors, proteolytic enzymes and inhibitors, proinflammatory cytokines, chaperones, and dysregulated stress response pathways including insufficient autophagy. Interaction between individual genetic predisposition and stress factors is a plausible theory explaining the development of XFS in the aging individual. Genome-wide association studies have identified robust genetic associations with LOXL1, CACNA1A, and 5 additional genes including POMP and TMEM136, which provide new biological insights into the pathology of XFS and highlight a role for abnormal matrix cross-linking processes, Ca channel deficiency, blood-aqueous barrier dysfunction, and abnormal ubiquitin-proteasome signaling in XFS pathophysiology. However, the exact pathophysiological mechanisms, the functional role of genetic risk variants, and gene-environment interactions still remain to be characterized.

Tear film abnormalities in pseudoexfoliation syndrome and normal healthy participants: A comparative analysis

Background

Pseudoexfoliative material is being implicated in causing tear film abnormalities, and the aim of the present study was to prove it and to compare with the normal healthy participants.

Methods

A total of 398 eyes of 200 participants were studied, and two groups were formed. The first, pseudoexfoliation syndrome (PEXS) group, included 198 eyes of 100 patients, and the second, age-matched control group, included 200 eyes of 100 participants. Tear film abnormalities were compared in the two groups by tear meniscus height (TMH), Schirmer test I, Schirmer test II and tear film break-up time (TBUT).

Results

On comparing the two groups using independent t-test, a significant difference was found in Schirmer test I, Schirmer test II, and TBUT between the PEXS group (Schirmer test I: 23.98 ± 10.68 mm, Schirmer test II: 17.11 ± 8.78 mm, and TBUT: 9.778 ± 5.54 s) and the age-matched control group (Schirmer test I: 27.08 ± 9.58 mm, Schirmer test II: 19.98 ± 8.48 mm, and TBUT: 13.495 ± 5.65 s) (p = 0.003 [Schirmer test I]; p = 0.001 [Schirmer test II]; and p < 0.001 [TBUT]). However, an insignificant difference was found in terms of TMH (p = 0.195) between the two groups.

Conclusion

PEXS affects tear production and leads to unstable tear film.

Comparison of cytokine/chemokine levels in aqueous humor of primary open-angle glaucoma patients with positive or negative outcome following trabeculectomy

We aimed to identify differences in cytokine/chemokine levels in the aqueous humor (AH) of primary open-angle glaucoma (POAG) patients who suffered from scarring, compared with POAG patients with no scarring after trabeculectomy surgery. Identification of differently expressed cytokines and chemokines may help to understand scarring and fibrotic processes following trabeculectomy, and to make predictions for the outcome of fistulating surgery in the future. Furthermore, the identification of cell signaling pathways involved in fibrosis offers the opportunity for a more specific antifibrotic therapy with reduced side effects, and an improvement in long-term surgical outcome.

Eight samples of AH were collected during trabeculectomy surgery and commercially available cytokine/chemokine arrays were used. Specific, differently expressed proteins (cytokines/chemokines) in AH samples from patients with positive and negative surgery outcomes were detected. These proteins were classified based on their known profibrotic, inflammatory, adhesive, and apoptotic properties. Transforming growth factor β (TGF-β) and vascular endothelial growth factor (VEGF) were among the most important profibrotic cytokines that we detected. Differences in the fold change of protein expression were highly significant between patients after successful and failed trabeculectomy surgery, and these were processed and visualized using ExprEssence software.

This pilot study revealed differences in concentrations of cytokines/chemokines in AH between the two examined groups of patients. Our findings suggest that a positive outcome from trabeculectomy is strongly related to an inhibition of the fibrosis process.

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.

Biomarkers for PVR in rhegmatogenous retinal detachment

PURPOSE

Various profibrotic and proinflammatory cytokines have been found upregulated in uncomplicated primary retinal detachment (pRD), but without providing a uniform picture. Here, we compare the cyto- and chemokine profiles in pRD with and without proliferative vitreoretinopathy (PVR) in an attempt to unravel relevant differences not in single cytokines, but in the cytokine profiles at diagnosis.

METHODS

Undiluted vitreous fluid (VF) was obtained at the beginning of surgery from 174 eyes with pRD without relevant PVR (maximally grade B; group 1; n = 81) and with moderate or advanced PVR requiring a gas tamponade (group 2; n = 49) or silicon oil filling (group 3; n = 44). VF of eyes undergoing macular hole (MH) surgery served as controls (group 4; n = 26). Forty-three cytokines were quantified in parallel using a multiplex cytokine analysis system (Bioplex). For all comparisons we applied Holm's correction to control for multiple comparisons.

RESULTS

44.9% of group 2 eyes presented grade C1 and 55.1% C2-C3, whereas 86.4% of group 3 eyes exhibited a PVR grade of C2-D. CCL19 was the only cytokine that displayed higher concentrations in the vitreous of eyes with PVR C1 compared to lower PVR grades. Eyes with PVR C2-D showed higher levels of CCL27, CXCL6, IL4, IL16, CXCL10, CCL8, CCL22, MIG/CXCL9, CCL15, CCL19, CCL 23 and CXCL12 compared to controls. Interestingly, no difference of cytokine levels was detected between C1 and C2-D PVR.

CONCLUSIONS

CCL19 may represent a potential biomarker for early PVR progression that holds promise for future diagnostic and therapeutic applications.

YKL-40 is a local marker for inflammation in patients with pseudoexfoliation syndrome

PURPOSE

To investigate the YKL-40, as a marker of inflammation, in aqueous humor and serum of cataract patients with and without pseudoexfoliation syndrome (PEX).

METHODS

Aqueous humor and serum samples were obtained from 44 patients who underwent phacoemulsification surgery. All patients were divided into two groups: PEX (n = 24) and control (n = 20). YKL-40 levels were measured with enzyme-linked immunosorbent assay (ELISA). The differences between the groups were assessed by using Chi-square and independent sample t-tests. The Pearson correlation coefficient was used to evaluate the correlation between variables.

RESULTS

There was a significant difference between the mean YKL-40 levels in the aqueous humor of PEX group (112.0 ± 35.8 ng/mL) and control subjects (88.2 ± 30.6 ng/mL) (P = 0.025). However, the difference between the mean YKL-40 levels in the serum of PEX group (53.5 ± 29.1 ng/mL) and control subjects (44.6 ± 30.2 ng/mL) was non-significant (P = 0.326). The correlation between aqueous humor and serum YKL-40 concentrations was significant in both the groups (r = 0.833, P < 0.001; r = 0.840, P < 0.001, respectively).

CONCLUSIONS

Increased aqueous humor levels of YKL-40 demonstrate that it is local, but not a systemic marker for inflammation in patients with PEX.

High interleukin-8 level in aqueous humor is associated with poor prognosis in eyes with open angle glaucoma and neovascular glaucoma

Glaucoma is a leading cause of blindness worldwide. Purpose of this study was to identify molecular markers that were significantly correlated with presence of glaucoma and outcome of glaucoma surgery. To accomplish this, we determined the profiles of pro-inflammatory cytokines in the aqueous humor of 101 glaucoma patients; 31 primary open angle glaucoma (POAG), 38 pseudoexfoliation glaucoma (PEG), and 32 neovascular glaucoma (NVG). We also studied 100 normal subjects as controls. In eyes with POAG or PEG, the level of interleukin (IL)-1α, IL-2, IL-4, IL-8, IL-23, and CCL2 were significantly elevated. In the NVG eyes, many inflammatory cytokines were also highly elevated. IL-8 had the highest odds ratio, and levels of IL-8 and CCL2 were significantly correlated with preoperative IOP or visual field defects in PEG eyes. Principal component analysis showed that IL-8 had the highest association to the IOP-cytokine component, and Cox proportional hazard model indicated that an elevation of IL-8 was a significant risk of filtering surgery failure. Together with modeling of their interactions and prognosis, IL-8 elevation is a significant risk factor both for detecting and managing glaucoma and may serve as a therapeutic target candidate to improve the prognosis of glaucoma surgery.

Infection of endotheliotropic human cytomegalovirus of trabecular meshwork cells

PURPOSE

Human cytomegalovirus (HCMV) infections can cause endotheliitis which is associated with an elevation in the intraocular pressure (IOP). However, the mechanism of the IOP elevation has not been established. The purpose of this study was to determine whether HCMV strains which are capable of infecting corneal endothelial cells can also replicate and induce anti-viral responses, and can reorganize the actin cytoskeleton in trabecular meshwork cells.

STUDY DESIGN

Experimental study design.

METHODS

Cultured primary human trabecular meshwork cells (HTMCs) were infected with the Towne or TB40/E strains of HCMV. TB40/E is trophic for vascular endothelial and corneal endothelial cells. Real-time PCR, western blot, and fluorescent immunostaining have been used to determine whether HCMV-infected HTMCs will support the expression of viral mRNA and protein, allow viral replication, and elicit anti-viral host responses. We also determined whether lytic replication was present after HCMV infection.

RESULTS

HCMV infection led to the expression of viral mRNA and proteins of IE1, glycoprotein B(gB), and pp65. TB40/E infection induced interferon-β, a sign of host anti-viral immune response and monocyte chemotactic protein-1 (MCP-1) as IOP-related chemokine. Together with the induction of the regulators of actin cytoskeleton, myosin phosphatase Rho interacting protein (MPRIP) and MCP-1, TB40/E induced a high level of expression of viral proteins, including IE1, gB, and pp65 as well as actin stress fiber formation, and achieved pathogenically high viral titers.

CONCLUSIONS

Human trabecular meshwork cells support the replication of endotheliotropic TB40/E strain of HCMV which indicates that this strain may have high virulence for trabecular meshwork.

Cytokine profiles in the aqueous humor and serum of patients with dry and treated wet age-related macular degeneration

PURPOSE

To identify disease-specific cytokine profile differences in the aqueous humor (AH) (other than the vascular endothelial growth factor) between patients with dry and treated wet age-related macular degeneration (AMD) and healthy controls.

METHODS

This retrospective study drew on a case-series of patients diagnosed with dry AMD (n = 25) and treated wet AMD (n = 19), as well as on healthy controls (no systemic therapy; n = 20) undergoing phacoemulsification or vitrectomy. Samples of AH and serum were collected in parallel at the beginning of surgery. The levels of 43 cytokines were simultaneously determined using the Bio-Plex® multiplex beads system. Differences between the three groups were statistically compared using the Kruskal-Wallis H-Test after applying the Bonferroni correction for multiple comparisons (p<0.0012).

RESULTS

The concentrations of three cytokines were elevated in the AH of patients with dry AMD (CXCL6; p = 0.00067) and treated wet AMD (CXCL5, CXCL6, MIG/XCXL; all p<0.001) relative to those in the healthy controls. No other differences between the three groups were identified. The AH levels of seven cytokines (16%), including CXCL6, ranged below the lower limit of quantitation of the assay. Without the correction for multiple comparisons (p<0.05), the levels of 31 of the 43 cytokines in the AH of patients with AMD would have differed significantly from those in the control. The systemic cytokine profiles (serum) were similar in all three groups.

CONCLUSIONS

No systematic differences in the AH cytokine environment were identified between patients with dry AMD and those with treated wet AMD. This finding might indicate that AMD is either the result of a persistent imbalance in the physiological tissue milieu, or that the localized process induces no significant change in the cytokine environment of the anterior ocular segment.