Age-related pro-inflammatory and pro-angiogenic changes in human aqueous humor

Effect of metformin on the level of aqueous humor inflammatory cytokines in patients with cataract

This study investigated the content of inflammatory cytokines in the aqueous humor (AH) of cataract patients with type 2 diabetes (T2DM) and explored the effect of metformin on the level of cytokines. AH was collected from patients undergoing phacoemulsification and intraocular lens implantation in Peking University Third Hospital. Levels of cytokines were measured by Cytometric Bead Assay (CBA) Flex Set. Differences in level of AH cytokines were compared between patients using metformin and non-metformin medicine as blood sugar control drug for T2DM and age-related cataract patients without T2DM. A total of 67 patients were included, including 19 healthy controls, 33 patients in the metformin group, and 15 patients in the non-metformin group. The results showed that IL-6 levels were significantly higher in the non-metformin group than the metformin group and the healthy control group (p = 0.019 and 0.014, respectively). IFN-γ levels were also significantly higher in the non-metformin group than the metformin group and the healthy control group (p = 0.031 and 0.003, respectively). The levels of IL-10 in non-metformin group were significantly higher than those in the healthy control group (p = 0.008), whereas the levels of IL-10 showed no significant difference between metformin group and healthy controls. Metformin can reduce the level of cytokines in AH to a certain extent in cataract patients combined with T2DM. It is suggested that metformin may have preventive and therapeutic effects on the development of age-related cataract.

Genetic susceptibility and causal pathway analysis of eye disorders coexisting in multiple sclerosis

Introduction

The comorbidity of optic neuritis with multiple sclerosis has been well recognized. However, the causal association between multiple sclerosis and optic neuritis, as well as other eye disorders, remains incompletely understood. To address these gaps, we investigated the genetically relationship between multiple sclerosis and eye disorders, and explored potential drugs.

Methods

In order to elucidate the genetic susceptibility and causal links between multiple sclerosis and eye disorders, we performed two-sample Mendelian randomization analyses to examine the causality between multiple sclerosis and eye disorders. Additionally, causal single-nucleotide polymorphisms were annotated and searched for expression quantitative trait loci data. Pathway enrichment analysis was performed to identify the possible mechanisms responsible for the eye disorders coexisting with multiple sclerosis. Potential therapeutic chemicals were also explored using the Cytoscape.

Results

Mendelian randomization analysis revealed that multiple sclerosis increased the incidence of optic neuritis while reducing the likelihood of concurrent of cataract and macular degeneration. Gene Ontology enrichment analysis implicated that lymphocyte proliferation, activation and antigen processing as potential contributors to the pathogenesis of eye disorders coexisting with multiple sclerosis. Furthermore, pharmaceutical agents traditionally employed for allograft rejection exhibited promising therapeutic potential for the eye disorders coexisting with multiple sclerosis.

Discussion

Multiple sclerosis genetically contributes to the development of optic neuritis while mitigating the concurrent occurrence of cataract and macular degeneration. Further research is needed to validate these findings and explore additional mechanisms underlying the comorbidity of multiple sclerosis and eye disorders.

Aqueous Humor Factors' Predictive Effects in Treating Refractor Macular Edema: An Overview

The refractory macular edema (RME) seriously affects the patient's vision due to its repetition and ineffective drug response. RME is mainly related to the inflammatory pathway and angiogenesis pathway. At present, microglia activation and angiogenesis have also been widely focused on. With the promotion of the concept of precision diagnosis and treatment, intraocular fluid is becoming a popular evidence-based method. The detection and evaluation of aqueous humor factors can provide more accurate evidences and guidance for the treatment of RME. The purpose of this article is to review the treatment prediction and assessment progress of aqueous humor cytokines for the RME, giving evidence to provide a basis for expanding the diagnosis and treatment ideas of RME and guiding the development of personalized medical treatment.

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.

Abnormal N-Glycosylation of Human Lens Epithelial Cells in Type-2 Diabetes May Contribute to Cataract Progression

Purpose

In order to better understand cataract development, we analyzed the glycosylation profile of human lens epithelial cells (HLECs) from anterior lens capsules of type 2 diabetes mellitus (T2DM) and non-diabetic (ND) patients undergoing routine cataract surgery.

Setting

Research Department of the Asociación para Evitar la Ceguera, Hospital "Dr. Luis Sánchez Bulnes", Mexico.

Design

Experimental study.

Methods

Evaluation of anterior lens capsules from T2DM and ND patients undergoing phacoemulsification and free from other ocular diseases.

Results

Hematoxylin-eosin staining revealed HLECs alterations in T2DM samples. From lectins with different sugar specificities used, concanavalin A showed significant differences, labeling homogeneously both in the cytoplasm and in cell membranes in ND capsules, while in T2DM capsules, in addition to membrane and cytoplasm labeling, there were perinuclear vesicles with high concanavalin A labeling. Two-dimensional gel electrophoresis showed that T2DM patients have a ~65-kDa spot with an isoelectric point of 5.5 with a higher density compared to ND capsules, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed 62% homology with type-1 cytokeratin. Immunohistochemistry using anti-pan cytokeratin antibody revealed co-localization with concanavalin A, and a lectin blot revealed with concanavalin A showed a band of ~65 kDa, a molecular weight that corresponds to human type 1 cytokeratin.

Conclusion

These results suggest that over-expression of N-glycosidically linked human type 1 cytokeratin may induce capsule disruption and affect selective permeability, allowing the entry of different molecules to the lens that facilitate cataract progression.

Changes of Serum Inflammatory Molecules and Their Relationships with Visual Function in Retinitis Pigmentosa

Purpose

Retinal degeneration involves neuroinflammation, and pro-inflammatory cytokines/chemokines are markedly increased in the eyes of patients with retinitis pigmentosa (RP). In this study, we investigated the changes of serum cytokines/chemokines in RP, and their relationships with visual parameters.

Methods

Forty-five consecutive patients with typical RP aged 20 to −39 years and 28 age-matched and gender-matched controls were included. Fifteen cytokines (interleukin [IL]-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, 1L-15, IL-17, IL-23, interferon [IFN]-γ, and tumor necrosis factor [TNF]-α, TNF-β) and 9 chemokines (eotaxin, growth-related oncogene [GRO]-α, I-309, IL-8, IFN-γ-inducible protein [IP]-10, monocyte chemotactic protein [MCP]-1, MCP-2, regulated activation normal T-cell expressed and secreted [RANTES], and thymus and activated regulated chemokine [TARC]) in the serum were simultaneously measured by a multiplexed immunoarray (Q-Plex). Relationships between these cytokines/chemokines and indices of central vision, such as visual acuity (VA), the values of static perimetry tests (Humphrey Field analyzer, the central 10-2 program), and optical coherence tomography measures were analyzed in the patients with RP.

Results

Among the 15 cytokines and 9 chemokines, serum IL-8 and RANTES levels were significantly increased in patients with RP compared with controls (IL-8: P < 0.0001; RANTES: P < 0.0001). Among the elevated cytokines/chemokines, the levels of IL-8 were negatively correlated with VA (ρ = 0.3596 and P = 0.0165), and the average retinal sensitivity of four central points (ρ = −0.3691 and P = 0.0291), and 12 central points (ρ = −0.3491 and P = 0.0398), as well as the central subfield thickness (ρ = −0.3961 and P = 0.0094), and ellipsoid zone width (ρ = −0.3841 and P = 0.0120).

Conclusions

Peripheral inflammatory response may be activated and serum IL-8 levels are associated with central vision in patients with RP.

Developmental characteristics of the cytokine profile in aqueous humor and its relationship with the inflammatory response in children

Background

Although influencing the severity of postoperative intraocular inflammation of congenital cataract, the developmental characteristics of cytokine profile in the aqueous humor during childhood had not been described. And its relationship with the inflammatory response after intraocular surgery remained unsolved.

Methods

Preoperative aqueous humor samples were collected from 65 eyes of congenital cataract patients (CC group) and 13 eyes of age-related cataract patients (ARC group) from January 2015 to May 2017. The concentrations of 22 cytokines were measured. Differences in concentrations between the CC and ARC groups were described. Correlation analysis, least absolute shrinkage and selection operator (LASSO) and multivariate linear regression were then used to investigate the dynamic changes in the cytokine profile with age and their relationships with the postoperative inflammatory response.

Results

The concentrations of granulocyte colony stimulating factor (G-CSF), interferon (IFN)-α2, interleukin (IL)-1α and IL-7 were higher in the CC group than in the ARC group, while the concentrations of epidermal growth factor (EGF), granulocyte-macrophage colony stimulating factor (GM-CSF), IL-10, IL-12p70, IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, and tumor necrosis factor (TNF)-α were more abundant in the ARC group (P<0.05). Within the CC group, the concentrations of EGF and IL-3 were positively correlated with age, while negative correlations were observed for monocyte chemotactic protein-1 (MCP-1) and IL-8 (P<0.05). Further multivariate analysis revealed that age was an independent associated factor of MCP-1 (β=−0.337, P<0.001). IL-3 (β=−0.490, P=0.006) and EGF (β=−0.415, P=0.044) were significantly correlated with the postoperative inflammatory response [evaluation of posterior capsule opacification (EPCO)] at 3 and 12 months after surgery, respectively.

Conclusions

This study demonstrated the dynamic change in the cytokine profile of the aqueous humor in children and its relationship with the postoperative inflammatory response. These findings can serve as the foundation for further investigation into the mechanisms that underlie the early development of intraocular immunology.

Cytokine and Chemokine Concentration in the Tear of Patients with Age-Related Cataract

PURPOSE

The present study measured 41 soluble mediators in the tear of 19 patients with age-related cataract and 32 healthy adults as controls.

MATERIALS AND METHODS

This was a prospective, case-control study in which, using multiple immunoassays, we measured in tear samples the following molecules: EGF, FGF-2, Eotaxin, TGF-α, G-CSF, Flt-3L, GM-CSF, Fractalkine, IFN-α2, IFN-γ, GRO, IL-10, MCP-3, IL-12p40, MDC, IL-12p70, PDGF-AA, IL-13, PDGF-AB/BB, IL-15, sCD40L, IL-17a, IL-1ra, IL-1α, IL-9, IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IP-10, MCP-1, MIP-1α, MIP-1β, RANTES, TNFα, TNFβ, VEGF. Statistical analyses were done by multiple adjusted models and p values were corrected by the Benjamini and Hochberg method.

RESULTS

We did not find significant differences in the amount of the tested molecules in the tear fluid between cataract patients and controls. Correlation analyses relative to age were carried out for both groups. Analysis of MCP-1 tear levels revealed a direct correlation with age for normal healthy controls as well as for cataract patients. But IL-6 tear levels correlated with age only in the group of cataract patients. In addition, IL1-ra tear levels correlated with cataract nuclear grade; higher grades were associated with higher IL-1ra concentrations.

CONCLUSIONS

Our results suggest that ocular aging is accompanied by increased production of IL-6 and MCP-1, which can be measured in tear fluid.

ABBREVIATIONS

AMD: Age-Related Macular Degeneration; EGF: Epidermal growth factor; Eotaxin: Eosinophil chemotactic proteins; FasL: Fas ligand; FGF-2: Basic fibroblast growth factor 2; Flt-3L: Fms related tyrosine kinase 3 ligand; G-CSF: Granulocyte colony stimulating factor; GM-CSF: Granulocyte macrophage colony stimulating factor; GRO: Growth regulated protein; HGF: Human growth factor; ICAM-1: Intercellular adhesion molecule-1; IFNα2: Interferon alpha 2; IFNγ: Interferon gamma; IL: Interleukin; IL-1ra: Interleukin-1 receptor antagonist; IL-12p40: Interleukin-12 subunit p40; IL-12p70: Interleukin-12 subunit p70; IP-10: Interferon gamma-induced protein 10; MCP-1: Monocyte chemotactic protein 1; MCP-3: Monocyte chemotactic protein 3; MDC: Macrophage derived chemokine; MIG: Monokine induced by gamma interferon; MIP-1α: Macrophage inflammatory proteins 1 alpha; MIP-1β: Macrophage inflammatory proteins 1 beta; MMPs: Matrix metalloproteinases; MMP-9: Matrix metalloproteinase 9; PAI1: Plasminogen activator inhibitor 1; PDGF-AA: Platelet-derived growth factor subunit AA; PDGF-AB/BB: Platelet-derived growth factor subunit AB and BB; PIGF: Placenta growth factor; RANTES: Regulated on activation, normal T cell expressed and secreted; SAA: Serum amyloid A; sCD40L: Soluble CD40 ligand; sTNF-RII: Soluble tumor necrosis factor receptor; TBUT Tear breakup time; TGF-α: Transforming growth factor alpha; TGF-β: Transforming growth factor beta; TNFα: Tumor necrosis factor alpha; TNFβ: Tumor necrosis factor beta; VCAM: Vascular cell adhesion molecule; VEGF: Vascular endothelium growth factor.

Soluble cytokine receptor levels in aqueous humour of patients with specific autoimmune uveitic entities: sCD30 is a biomarker of granulomatous uveitis

Purpose

Soluble cytokine receptors are potential biomarkers for immune activation and have a promising potential as immunotherapeutic agents. We investigated the levels of soluble cytokine receptors in aqueous humour (AH) samples from patients with specific autoimmune uveitic entities.

Methods

Patients with active uveitis associated with Behçet’s disease (BD) (n = 13), sarcoidosis (n = 8), HLA-B27-related inflammation (n = 12), Vogt–Koyanagi–Harada (VKH) disease (n = 12) and control subjects (n = 9) were included. AH samples were analyzed with the use of multiplex assays for the proinflammatory cytokine tumour necrosis factor (TNF)-α and the soluble cytokine receptors sCD30, sCD163, sgp130, sIL-6 receptor-α (sIL-6R), sTNFRI and sTNFRII.

Results

TNF-α and soluble cytokine receptor AH levels were significantly higher in uveitis patients (n = 45) compared with controls (n = 9). When nongranulomatous uveitis (BD and HLA-B27-associated uveitis) was compared with granulomatous uveitis (sarcoidosis and VKH disease), the levels of sCD30 and sTNFRI/TNF-α and sTNFRII/TNF-α ratios were significantly enhanced in granulomatous uveitis. Finally, when comparing the profile in the specific uveitis entities, sCD30 levels were highest in patients with VKH disease. sgp130, sCD163, sIL-6R, sTNFRI and sTNFRII did not differ significantly between the four different clinical uveitic subgroups.

Conclusions

Soluble cytokine receptors are significantly upregulated in autoimmune uveitis. CD30⁺ T cells might contribute to the inflammatory process in granulomatous uveitis, particularly in VKH disease. Granulomatous uveitis is also characterized by significantly higher sTNFRs/TNF-α ratios than nongranulomatous uveitis.