Evaluation of Cross-Linked Actin Networks (CLANs) in Human Trabecular Meshwork Cells and Tissues.

Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of glaucoma, the leading cause of irreversible vision loss and blindness. An overall increase in resistance to aqueous humor outflow causes sustained elevation in IOP. Glaucomatous insults in the aqueous humor outflow pathway, including the trabecular meshwork (TM), precede such chronic physiological changes in IOP. These insults include ultrastructural changes with excessive extracellular matrix deposition and actin cytoskeletal reorganization that leads to pathological stiffening of the ocular tissues. One of the most common cytoskeletal changes associated with TM tissue stiffness in glaucoma is the increased prevalence of cross-linked actin networks (CLANs) in cells of the trabecular meshwork (TM) and lamina cribrosa (LC). In glaucomatous cells, rearrangement of linear actin stress fibers leads to formation of polygonal arrays within the cytoplasm, resembling a geodesic dome-like structure, that we identified as CLANs. In addition to increased amounts of CLANs in POAG TM cells and tissues, we also discovered that glucocorticoid (GC) and TGFß2 signaling pathways associated with the development of ocular hypertension (OHT) and glaucoma also induced CLANs in the TM. Despite a clear association, we are yet to completely understand the mechanisms involved in CLAN formation and their direct relevance to disease pathology. In this chapter, we will describe methods to identify and characterize CLANs using fluorescent microscopy in primary TM cell cultures, ex vivo perfusion cultured human anterior segments, and in situ in human donor eyes.

Nanotubules and Cellular Communication in Trabecular Meshwork Cells.

Glaucoma causes dysfunction to tissues located in the anterior and posterior eye. In the anterior eye, the trabecular meshwork (TM) is the site of pathogenesis, where decreased TM cell numbers and alterations to the amount and composition of extracellular matrix hinder outflow of aqueous humor fluid from the anterior chamber. This causes intraocular pressure (IOP) elevation. Elevated IOP, a main risk factor for primary open-angle glaucoma, damages the axons of retinal ganglion cells in the posterior eye, which ultimately leads to blindness. Thus, clinical treatment paradigms for glaucoma are focused on reducing IOP. Normotensive IOPs are established by balancing the production of aqueous fluid from the ciliary body with drainage through the TM to Schlemm's canal. When IOP becomes elevated, TM cells coordinate a homeostatic response to lower IOP, which requires effective and efficient cellular communication. Tunneling nanotubes (TNTs) are transient specialized structures that allow cells to communicate with one another. Actin-rich tubes allow direct transmission of signals and cargoes between cells. This is important to overcome limitations of diffusion-based signaling in aqueous environments such as the anterior eye. Here, we describe a live-cell imaging method for monitoring TNTs in primary TM cells.

Time-Lapse Live-Cell Imaging Using Fluorescent Protein Sensors in Outflow Pathway Cells Under Fluid Flow Conditions.

The role of shear stress in regulating aqueous humor (AH) outflow and intraocular pressure (IOP) in the trabecular meshwork (TM) and Schlemm's canal (SC) of the eye is an emerging field. Shear stress has been shown to activate mechanosensitive ion channels in TM cells and induce nitric oxide production in SC cells, which can affect outflow resistance and lower IOP. Live-cell imaging using fluorescent protein sensors has provided real-time data to investigate the physiological relationship between fluid flow and shear stress in the outflow pathway cells. The successful application of time-lapse live-cell imaging in primary cultured cells has led to the identification of key cellular and molecular mechanisms involved in regulating AH outflow and IOP, including the role of autophagy and primary cilia as mechanosensors. This chapter presents a detailed protocol for conducting time-lapse live-cell imaging under fluid flow conditions in the outflow pathway cells.

Protocol for the Extraction and Characterization of Trabecular Meshwork Cell Cytoskeleton Fraction.

Among various cellular attributes modulating aqueous humor (AH) outflow through the trabecular pathway and eventually intraocular pressure, the involvement of actomyosin regulated cellular contraction and relaxation, cell-extracellular matrix adhesion and cell-cell junctions, and mechanotransduction are well recognized. Although various biological and pharmacological agent-modulated AH outflows were associated with altered actin cytoskeletal organization and cell adhesive interactions of trabecular meshwork (TM) cells, these changes were analyzed largely with a biased approach to examine the specific proteins, but there were very few efforts in examining them with hypothesis-free unbiased approach in their native state. Therefore, in this chapter, we describe a protocol tailored to characterize the cytoskeleton of TM cells. This simple protocol can be applied to identifying the differentially regulated TM cell cytoskeleton proteins under any given treatment condition in conjunction with quantitative proteomic analysis.

Human Anterior Segment Perfusion Organ Culture.

The human anterior segment perfusion organ culture is an ex vivo model system for studying the human conventional outflow pathway with reference to pressure regulation. In this model, anterior segments dissected from human donor eyes can be fixed to a modified petri dish and perfused with media along with various study agents at the physiological flow rate of 2.5 µL/min. The model mimics the one-way flow of aqueous humor in human eyes and can be used to evaluate the effects of various drugs on eye pressure in real time. Using this model, cells and tissues of the anterior segment can be maintained for up to 28 days, enabling histological and molecular evaluations.

Segmental Aqueous Humor Outflow.

Of the known risk factors for glaucoma, elevated intraocular pressure (IOP), is the primary one. The conventional aqueous humor outflow pathway contains the key source of IOP regulation, which is predominantly the trabecular meshwork (TM). Studies of outflow have demonstrated that the outflow pathway is not uniform around the circumference of the eye but highly segmental with regions of relative high flow (HF) and intermediate or medium flow (IF) and regions of low or no flow (LF). Herein we present protocols that we use to study outflow segmentation through the conventional outflow pathway, mostly focusing on human eyes. These methods are quite similar for nonhuman primates and other species. These studies are mostly conducted using ex vivo intact globes or perfused anterior segment organ culture. One potential therapy for IOP reduction in those with elevated IOP to reduce progression of glaucomatous optic nerve damage would be to increase HF or IF and reduce LF proportions.

Aqueous Humor Angiography.

Aqueous humor angiography, or aqueous angiography, is an anterior segment imaging technique capable of visualizing the conventional/trabecular aqueous humor outflow pathways. As a translational technique, it is applicable for in vivo imaging in living subjects and ex vivo imaging using whole-globe preparations or anterior segment perfusion setups. Excellent spatial and temporal resolution has enabled insights into the segmental distribution of aqueous humor outflow in physiological conditions as well as after trabecular bypass surgery. In this chapter, we thoroughly describe aqueous humor angiography in various experimental setups. The necessary materials for different settings and their application for in vivo and ex vivo experiments as well as notes on dye choice, dye sequences, and special considerations on performing aqueous humor angiography during surgery are presented.

Molecular changes in intraocular fluid: implications for myopia.

Myopia is the most common eye disease in the world which is caused by a mismatch between the optical power of the eye and its excessive axial length. Scleral remodeling, oxidative stress, inflammation, pathological states of angiogenesis and fibrosis and metabolism are closely associated with the onset and progression of myopia and the pathological changes that may ultimately result. Intraocular fluid is a collective term for the fluid within the eye, and changes in its composition can reflect the physiological and pathological status within the eye, with aqueous humor and vitreous being the commonly tested specimens. Recent studies have revealed potential changes in a variety of molecules in intraocular fluid during myopia progression. Abnormal expression of these molecules may reflect different stages of myopia and provide new perspectives for disease monitoring and treatment. Therefore, in this review, we systematically review the molecular changes in intraocular fluid associated with myopia, as well as the possible mechanisms, with a view to informing basic myopia research and clinical work.

Untargeted Metabolomic Study of Patients with Wet Age-Related Macular Degeneration in Aqueous Humor.

Purpose: The objective of this study was to ascertain metabolic biomarkers and investigate the metabolic alterations associated with aqueous humor (AH) in wet age-related macular degeneration (AMD). Methods: AH samples were collected from a total of 20 participants, including 10 individuals diagnosed with wet AMD and 10 individuals undergoing cataract surgery, serving as the control group. Metabolomics analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify and quantify metabolites. Results: A total of 155 metabolites were identified in the AH samples. Among them, 10 metabolites emerged as potential biomarkers capable of differentiating patients with wet AMD from the control group. In the AH of wet AMD patients, there was increased expression of Cardiolipin (CL) (72:5), Diglyceride (DG) (18:3_18:2), DG (36:5e) and Triglyceride (TG) (24:7), while the expression of Ceramides (Cer) (d32:0), Cer (d34:0), Cer (d36:0), Monogalactosyldiacylglycerol (MGDG) (16:1_18:3), Sphingosine (SPH) (d18:0) and TG (16:0_10:4_16:0) was down regulated. Conclusion: Through metabolomics analysis of AH, this study successfully uncovered valuable metabolic biomarkers linked to wet AMD. These findings contribute to a more comprehensive understanding of the pathogenesis of wet AMD and offer potential avenues for the development of innovative treatment strategies for this condition.

The effect of age on aqueous humor of humans with high myopia.

Background: High myopia is a common cause of vision loss. Age is an important factor in the development of high myopia. However, the effect of age on aqueous humor proteins in the context of high myopia is unknown. This study explored the effect of age on the aqueous humor protein of humans with high myopia. Methods: The aqueous humor of high myopia patients of different ages with implantable collamer lens implantation (ICL) was collected. Data-independent acquisition proteomic analysis was employed to explore differentially expressed proteins (DEPs). Two different bioinformatics analysis methods were used to interpret the proteomic results. Furthermore, three proteins were confirmed by enzyme-linked immunosorbent assay (ELISA). Results: The study showed 18 upregulated and 20 downregulated proteins. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the upregulated DEPs were highly enriched in coagulation and complement cascades. Weighted gene coexpression network analysis showed that the blue module was identified as a key module for high myopia and that the plasminogen (PLG) protein is a hub protein. ELISA confirmed that the expression levels of Alpha-1-antitrypsin were significantly upregulated in the aqueous humor of older patients presenting with high myopia. Conclusions: This is the first study to investigate the effect of age on the level of aqueous humor protein in high myopia. Our study provided a comprehensive data set on the overall protein changes of different ages of human high myopia, shedding light on its potential molecular mechanism in high myopia damage to the eyeball.

Fetuin-B Interacts With Insulin Receptor-ß and Promotes Insulin Resistance in Retina Cells.

Purpose: The purpose of this study was to investigate the correlation between insulin and Fetuin-B (FETUB) and the influence of FETUB on insulin signaling pathway in diabetic retinopathy (DR). Methods: Enzyme-linked immunosorbent assay (ELISA) was used to analyze FETUB and insulin levels in the serum and aqueous fluid of patients with DR and healthy controls. Quantitative PCR (q-PCR), Western blotting, and ELISA were used to examine FETUB expression in ARPE-19, BV2, and Müller cells under insulin stimulation. Co-immunoprecipitation was used to investigate the interaction of FETUB with insulin receptor-ß (IRß). Insulin resistance (IR)-BV2 and IR-Müller cells were treated with FETUB recombinant protein or FETUB short hairpin RNA (shRNA) to explore the influence of FETUB on insulin signaling pathway in DR. LY294002 (a PI3K pathway inhibitor) was used to determine whether FETUB affects glucose metabolism via the PI3K/Akt pathway. Results: In aqueous fluid, FETUB concentrations were positively correlated with insulin levels. FETUB expression increased in Müller and BV2 cells under insulin regulation, and FETUB interacted with IRß in retinal cells and mice retina. The interaction between IRß and FETUB increased in BV2 and Müller cells under high-glucose than in controls. Insulin signaling pathway activation was suppressed in FETUB recombinant protein-treated BV2 and Müller cells but increased in FETUB shRNA-transfected cells. FETUB shRNA could not reverse LY294002-mediated inhibition of glucose transporter-4 expression. Conclusions: Retinal cells are the source of insulin-regulated FETUB. The FETUB interacts with IRß and affects insulin signaling pathway in BV2 and Müller cells. FETUB may aggravate IR in BV2 and Müller cells via the PI3K/Akt pathway.

Multiple cytokine analysis of aqueous humor in uveitis with or without secondary glaucoma.

To assess the level of both pro-inflammatory and anti-inflammatory cytokines in the aqueous humor (AH) of patients suffering from uveitis, with or without coexisting glaucoma, and compare them with patients diagnosed with primary open-angle glaucoma (POAG) and those with age-related cataract (ARC). By using Luminex xMAP® multiplex assays analyses, we assessed levels of 11 cytokines and chemokines, and compared them across groups, including uveitis-secondary glaucoma (USG) (n = 16), uveitis without glaucoma (UwoG), (n = 16), POAG (n = 16), and ARC (n = 16) to explore the correlation between these cytokines and the presence of uveitis, as well as intraocular pressure (IOP). Pro-inflammatory factors MCP-1, MIP-1ß, IL-6, IL-8, and transforming growth factors TGF-ß1 and TGF-ß2 were significantly elevated in the AH of USG eyes. In the case of enhanced anti-inflammatory in the perioperative period, the pro-inflammatory factors remained notably elevated in the USG group compared to the UwoG group (P < 0.01). The levels of IL-6, IL-8, and MCP-1 in the AH of the USG group and POAG group had the same trend, which markedly surpassed those of the ARC group (P < 0.01). Significantly increased levels of MCP-1, MIP-1ß, IL-6, IL-8, TGF-ß1, and TGF-ß2 were found in the AH of USG patients, implying a potential role for these mediators in the progression of glaucomatous manifestations within patients with uveitis. Besides the analysis revealed no discernible statistical disparity in cytokine concentrations within the AH of USG eyes whether the preoperative baseline IOP was greater than 30 mmHg or not, indicating that the safety of antiglaucoma surgery in USG patients even with baseline high IOP.

Low Intraocular Pressure Induces Fibrotic Changes in the Trabecular Meshwork and Schlemm's Canal of Sprague Dawley Rats.

Purpose: Continuous artificial aqueous humor drainage in the eyes of patients with glaucoma undergoing trabeculectomy likely exerts abnormal shear stress. However, it remains unknown how changes in intraocular pressure (IOP) can affect aqueous humor outflow (AHO). Methods: Here, we induced and maintained low intraocular pressure (L-IOP) in healthy Sprague Dawley (SD) rats by puncturing their eyes using a tube (200-µm diameter) for 2 weeks. After the rats were euthanized, their eyes were removed, fixed, embedded, stained, and scanned to analyze the physiological and pathological changes in the trabecular meshwork (TM) and Schlemm's canal (SC). We measured SC parameters using ImageJ software and assessed the expression of various markers related to flow shear stress (KLF4), fibrosis (TGF-ß1, TGF-ß2, α-SMA, pSmad1/5, pSmad2/3, and fibronectin), cytoskeleton (integrin ß1 and F-actin), diastolic function (nitric oxide synthase and endothelial nitric oxide synthase [eNOS]), apoptosis (cleaved caspase-3), and proliferation (Ki-67) using immunofluorescence or immunohistochemistry. Results: L-IOP eyes showed a larger SC area, higher eNOS expression, and lower KLF4 and F-actin expression in the TM and SC (both P < 0.05) than control eyes. The aqueous humor of L-IOP eyes had a higher abundance of fibrotic proteins and apoptotic cells than that of control eyes, with significantly higher TGF-ß1, α-SMA, fibronectin, and cleaved caspase-3 expression (all P < 0.05). Conclusions: In conclusion, a persistence of L-IOP for 2 weeks may contribute to fibrosis in the TM and SC and might be detrimental to conventional AHO in SD rat eyes. Translational Relevance: Clinicians should consider that aberrant shear force induced by aqueous humor fluctuation may damage AHO outflow channel when treating patients.

Changes in PEDF, MMP-2, and TGF-ß2 levels in the aqueous humor of cataract patients and their correlation with disease severity.

OBJECTIVE: To explore the changes of Pigment Epithelium-Derived Factor (PEDF), Matrix Metalloproteinase-2 (MMP-2), and Transforming Growth Factor-ß2 (TGF-ß2) levels in the aqueous humor of cataract patients and their correlation with disease severity. METHODS: 93 cataract patients and 56 healthy subjects were study objects. PEDF, MMP-2, and TGF-ß2 levels of aqueous humor were compared, and the correlation between each index and Lens Opacity Classification System (LOCS) III classification was analyzed. ROC curve was used to analyze the evaluation value of the combined detection of each index on cataract development, and logistic regression to analyze the influence of the changes of each index on cataract development. RESULTS: PEDF levels were lower and MMP-2 and TGF-ß2 levels were higher in the aqueous humor of cataract patients than in healthy subjects. PEDF levels in the aqueous humor were negatively correlated with LOCS III classification, while MMP-2 and TGF-ß2 levels were positively correlated with LOCS III classification. The AUC value of combined detection was higher than that of PEDF, MMP-2, and TGF-ß2 in the aqueous humor alone. MMP-2 ≥ 15.13 pg/mL, TGF-ß2 ≥ 385.91 pg/mL and PEDF < 198.85 ng/mL were risk factors for cataract development. CONCLUSION: The changes in PEDF, MMP-2, and TGF-ß2 levels in the aqueous humor of cataract patients are related to LOCS III classification. The combined detection is valuable in evaluating cataract development.

A case of masquerade syndrome caused by metastatic iris tumor diagnosed by a high CEA level in the aqueous humor and iris biopsy.

BACKGROUND: With the advent of targeted therapies, the survival prognosis for metastatic tumors has extended, and it has become necessary to diagnose and consider treatment that takes into account Quality of Life for metastatic tumors of the eye. The reports of checking tumor marker in the aqueous humor for diagnosis of metastatic intraocular tumors are few. Here, we report a case of masquerade syndrome with secondary glaucoma in which a high carcinoembryonic antigen (CEA) level in the aqueous humor could assist diagnosis, and continuing targeted therapy and trabeculectomy were effective. CASE PRESENTATION: A 73-year-old man was referred to us for iritis and high intraocular pressure (IOP) with severe eye pain in the left eye. He had Stage IVB lung adenocarcinoma treated with a molecularly targeted drug, Osimertinib. His best corrected visual acuity was 0.15, and IOP was 52 mmHg in the left eye. Anterior chamber cells (+), numerous small nodules in the iris, and small masses in the inferior angle were observed. In the aqueous humor, the CEA level was higher than in the blood. Napsin A and Thyroid Transcription Factor-1 (TTF-1) positive cells showed in the resected tissue at iridectomy performed during trabeculectomy. The pathological diagnosis of metastatic iris tumor of the lung adenocarcinoma was made, and we injected bevacizumab intravitreally once and continued Osimertinib. His IOP lowered to 8-10 mmHg, and the iris masses disappeared. He lost vision by metastasis to the left optic nerve after termination of Osimertinib one and a half years later. The metastasis shrank after restarting the drug. He passed away from an exacerbation of his primary lung cancer two years and nine months after the first visit. Although he lost vision in his left eye, the metastatic tumor in his left eye and optic nerve had disappeared, and his quality of life was maintained without any pain in his eye. CONCLUSIONS: Checking tumor markers in the aqueous humor can aid in diagnosis, and aggressive treatment of metastatic iris tumors must help maintain patients' Quality of Life.

Oxylipins in Aqueous Humor of Primary Open-Angle Glaucoma Patients.

PURPOSE: Investigate the oxylipin profiles in the aqueous humor of primary open-angle glaucoma (POAG) patients. METHODS: Aqueous humor samples were collected from 17 POAG patients and 15 cataract subjects and subjected to a liquid chromatography/mass spectrometry (LC-MS) analysis to detect the oxylipins. The prediction potential of the differential abundant oxylipins was assessed by the receiver operating characteristic (ROC) curves. Pathway and correlation analyses on the oxylipins and clinical and biochemical parameters were also conducted. RESULTS: The LC-MS analysis detected a total of 76 oxylipins, of which 29 oxylipins reached the detection limit. The multivariate analysis identified five differential abundant oxylipins, 15-keto-prostaglandin F2 alpha (15-kPGF2α), Leukotriene B4 (LTB4), 12,13-Epoxyoctadecenoic acid (12,13-Epome), 15-Hydroxyeicosatetraenoic acid (15-HETE) and 11-Hydroxyeicosatetraenoic acid (11-HETE). The five oxylipins are enriched in the arachidonic acid metabolism and linoleic acid metabolism pathways. Pearson correlation analysis showed that 11-HETE was positively correlated with intraocular pressure and central corneal thickness and negatively with cup/disk area ratio in the POAG patients. In addition, 15-kPGF2α was moderately and positively correlated with the mean deviation (MD) of visual field defect, and LTB4 was moderately and negatively correlated with macular thickness. CONCLUSIONS: This study revealed the oxylipin profile in the aqueous humor of POAG patients. Oxylipins involved in the arachidonic acid metabolism pathway could play a role in POAG, and anti-inflammatory therapies could be potential treatment strategies for POAG.

Targeted Proteomics Profiling for Biomarker Discovery in Glaucoma Using the Olink Proteomics Platform.

Metabolic dysfunction plays a crucial role in the pathogenesis of glaucoma. In this study, we used Olink proteomics profiling to identify potential biomarkers for glaucoma. Aqueous humor samples were obtained from 44 cataract patients and 44 glaucoma patients. We identified 84 differentially expressed metabolic proteins between the glaucoma and the cataract group. Gene Ontology enrichment analysis highlighted the involvement of these proteins in ER-associated degradation pathway, regulation of interleukin-13 production, and DNA damage response pathway. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis further revealed links to pathways, such as tyrosine and pyrimidine metabolism. Among these, ALDH1A1 emerged as a candidate with a significant diagnostic potential for glaucoma. ALDH1A1 also exhibited a prominent role in the protein-protein interaction network. Elevated levels of ALDH1A1 in the aqueous humor of glaucoma patients were confirmed both in clinical samples and in an ischemia/reperfusion model. Functional assays confirmed that elevated ALDH1A1 induced retinal ganglion cell (RGC) apoptosis in vitro and demonstrated its pro-apoptotic role in RGCs in vivo. Collectively, these findings not only underscore the significance of ALDH1A1 in glaucoma but also provide valuable insights into clinical decision-making and therapeutic strategies.

Aqueous Humor Cytokine Analysis in Age-Related Macular Degeneration After Switching From Aflibercept to Faricimab.

Purpose: To examine the changes in aqueous humor cytokine levels and clinical outcomes of switching from aflibercept to faricimab in eyes with neovascular age-related macular degeneration (nAMD). Methods: Fifty-four eyes of 54 patients with AMD undergoing treatment with aflibercept under a treat-and-extend (TAE) regimen were switched to faricimab and studied prospectively. Best-corrected visual acuity (BCVA; in logarithm of the minimum angle of resolution), central retinal thickness (CRT), central choroidal thickness (CCT), and exudative status were analyzed using optical coherence tomography. Aqueous humor was collected before and after the switch, and angiopoietin-2 (Ang-2), placental growth factor (PlGF), and vascular endothelial growth factor (VEGF) A levels were measured. Results: After switching from aflibercept to faricimab, exudative changes improved in 28 eyes (52%), remained stable in eight eyes (15%), and worsened in 18 eyes (33%). BCVA changed from 0.27 ± 0.31 to 0.26 ± 0.29 (P = 0.46), CRT decreased from 306.2 ± 147.5 µm to 278.6 ± 100.4 µm (P = 0.11), and CCT changed from 189.5 ± 92.8 µm to 186.8 ± 93.9 µm (P = 0.21). VEGF-A levels were below the detection sensitivity in many cases throughout the pre- and post-switching periods. Ang-2 significantly decreased from 23.8 ± 23.5 pg/mL to 16.4 ± 21.9 pg/mL (P < 0.001), and PlGF significantly increased from 0.86 ± 0.85 pg/mL to 1.72 ± 1.39 pg/mL (P < 0.001). Conclusions: Switching from aflibercept to faricimab in patients with nAMD may not only suppress VEGF-A but also Ang-2 and reduce exudative changes.

Prospective Cytokine Profiling in Aqueous Humor Reveals a Proinflammatory Microenvironment in Highly Dense Nuclear Cataracts.

Purpose: To investigate if the cytokine profile in the aqueous humor (AH) of cataract patients varies according to cataract type and severity. Methods: This prospective study included 397 eyes of 397 patients (median age, 76 years; range, 30-94 years) who underwent standard small-incision phacoemulsification surgery. Cataracts were graded using the LOCS III system: mild (≤3), moderate (3.5-5), and severe (≥5). Biometric measurements from the IOL master 700 (Zeiss, Oberkochen, Germany) were used to differentiate between thick (>4.5 mm) and thin lenses. Information about age, gender, and self-reported diseases was obtained from patient records. Eleven different proteins were measured in AH using a multiplex cytokine assay (AYOXXA Biosystems, Cologne, Germany), including IL- 6, IL-8, angiopoietin 2, C-reactive protein (CRP), vascular endothelial growth factor A (VEGF-A), platelet-derived growth factor BB, placental growth factor, CXCL12, CXCL13, and CXCL10. Statistical analysis was performed using R and included nonparametrical testing, linear regression, and k-means clustering. Results: Higher nuclear LOCS grades correlated with increased levels of CCL2 (360 vs. 387 vs. 517 pg/mL, P < 0.001), VEGF-A (270 vs. 292 vs. 390 pg/mL, P = 0.012), IL-8 (3.1 vs. 4.2 vs. 5.7 pg/mL, P = 0.018), and CXCL10 (52 vs. 61 vs. 90 pg/mL, P = 0.003). No associations were observed for cortical and subcapsular cataracts. Thicker lenses were associated with significantly increased levels of CRP, CXCL10, CXCL12, IL-6, IL-8, and VEGF-A. Conclusions: The cytokine profile of AH varies based on cataract grading and lens thickness. In highly dense nuclear cataracts, CCL2, VEGF-A, IL-8, and CXCL10 were elevated.

Poor Response to Bevacizumab Correlates With Higher IL-6 and IL-8 Aqueous Cytokines in AMD.

Purpose: To evaluate the effect of intravitreal bevacizumab on aqueous levels of a panel of 12 inflammatory cytokines in patients with neovascular age-related macular degeneration (nAMD) and correlate response to treatment, as measured by change in the central subfovea thickness (CST), with cytokine levels. Methods: Thirty-three treatment-naïve patients with nAMD received a loading dose of intravitreal bevacizumab consisting of three injections at six weekly intervals. The aqueous samples prior to the first (baseline), second (week 6), and third (week 12) injections were analyzed for cytokine levels. Participants were subgrouped based on changes in CST on spectral-domain optical coherence tomography (SD-OCT) at 12 weeks. Group 1 included patients with a decrease in CST (responders; n = 27). Group 2 included patients who had no decrease in CST (poor responders; n = 6). Results: Aqueous IL-8 was the only cytokine to demonstrate a significant difference in levels between responders and poor responders, with higher interleukin-8 (IL-8) at week 12 in the poor responder group. Aqueous IL-6 and IL-8 levels showed a positive correlation with CST on SD-OCT (Spearman r = 0.45 and 0.55, respectively). There was a temporal increase overall in cytokine concentration accompanying bevacizumab treatment. Conclusions: Aqueous IL-6 and IL-8 may be important markers of treatment response or poor response in nAMD. Future therapeutic strategies may include targeted treatment against both vascular endothelial cell growth factor (VEGF) and IL-6 and/or IL-8 in patients who do not respond to anti-VEGF treatment alone.