Aqueous cytokine and growth factor levels indicate response to ranibizumab for diabetic macular oedema

Use of Ranibizumab for evaluating focal laser combination therapy for refractory diabetic macular edema patients: an exploratory study on the RELAND trials

Anti-vascular endothelial growth factor (VEGF) therapy is the first-line treatment for diabetic macular edema (DME), but is less effective in some patients. We conducted a prospective study to determine whether laser combination therapy with anti-VEGF was more effective than Ranibizumab monotherapy in anti-VEGF-resistant DME patients. There was no significant difference in the improvement of the best-corrected visual acuity (BCVA) between the laser combination therapy and Ranibizumab monotherapy groups (3.2 letters and -7.5 letters, p = 0.165). BCVA did not significantly change between visits 1 and 7 (the laser combination group, 64.3 letters 70.3 letters, respectively, p = 0.537; the Ranibizumab monotherapy group, 72.3 letters and 64.8 letters, respectively, p = 0.554), with no significant improvements in central foveal retinal thickness (the laser combination therapy group, 9.3%: the Ranibizumab monotherapy groups, - 7.3%; p = 0.926). There was no significant difference in the number of Ranibizumab intravitreal therapy (IVT) sessions between the groups (laser combination therapy, 5.2; ranibizumab monotherapy, 6.0; p = 0.237). This study did not show that laser combination therapy was significantly more effective for anti-VEGF-resistant DME than anti-VEGF monotherapy alone. Therefore, for anti-VEGF-resistant DME, alternative therapeutic approaches beyond combined laser therapy may be considered.

Persistent diabetic macular edema: Definition, incidence, biomarkers, and treatment methods

Intravitreal antivascular endothelial growth factor (anti-VEGF) treatment has drastically improved the visual and anatomical outcomes in patients with diabetic macular edema (DME); however, success is not always guaranteed, and a proportion of these eyes demonstrate persistent DME (pDME) despite intensive treatment. While standardized criteria to define these treatment-resistant eyes have not yet been established, many studies refer to eyes with no clinical response or an unsatisfactory partial response as having pDME. A patient is considered to have pDME if the retinal thickness improves less than 10-25% after 6 months of treatment. A range of treatment options have been recommended for eyes with pDME, including switching anti-VEGF agents, using corticosteroids and/or antioxidant drugs in adjunct with anti-VEGF therapy, and vitrectomy. In addition, multimodal imaging of DME eyes may be advantageous in predicting the responsiveness to treatment; this is beneficial when initiating alternative therapies. We explore the literature on persistent DME regarding its defining criteria, incidence, the baseline biological markers that may be useful in anticipating the response to treatment, and the available treatment options.

Evaluation of microaneurysms as predictors of therapeutic response to anti-VEGF therapy in patients with DME

Administration of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy is the first-line therapy for diabetic macular oedema (DME). However, some patients show no or insufficient response to repeated anti-VEGF injections. Therefore, it is necessary to identify factors that can predict this resistance against anti-VEGF treatment. Presence of microaneurysms (MAs) is a predictor of the development and progression of DME, but its relationship with the treatment response to the anti-VEGF agents is not well known. Therefore, we aimed to elucidate the relationship between the distribution of MAs and the response to anti-VEGF therapy in patients with DME. The number of MAs was measured before anti-VEGF therapy in each region using fluorescein angiography, indocyanine green angiography (IA), and optical coherence tomography angiography. Patients with DME were divided into the responder and non-responder groups after three loading phases. Differences in the distribution of MAs between the groups were investigated. Pre-treatment IA revealed more MAs in the nasal area in the non-responder group than in the responder group (10.7 ± 10.7 and 5.7 ± 5.7, respectively, in the nasal macula) (1.4 ± 2.1 and 0.4 ± 0.7, respectively, in the nasal fovea). Whereas, pre-treatment FA and OCTA could not reveal significantly difference between the groups. Detection of MAs in the nasal macula using pre-treatment IA may indicate resistance to anti-VEGF therapy. We recommend the clinicians confirm the presence of MAs in the nasal macula, as shown by IA, as a predictor of therapeutic response to anti-VEGF therapy in patients with treatment naive DME.

Exploring the angiographic-biologic phenotype in the IMAGINE study: quantitative UWFA and cytokine expression

BACKGROUND

This study investigates the association of intraocular cytokine expression and ultrawide-field fluorescein angiography (UWFA) quantitative imaging biomarkers and their association with angiographical feature response after antivascular endothelial growth factor (VEGF) therapy in diabetic macular oedema (DME).

METHODS

The IMAGINE DME study is a post hoc imaging biomarker and intraocular cytokine assessment from the DAVE study, a prospective DME clinical trial that included aqueous humour sampling and UWFA imaging. Fifty-four cytokines associated with inflammation and angiogenesis were evaluated through multiplex arrays. UWFA parameters were assessed using an automated feature analysis platform to determine ischaemic and leakage indices and microaneurysm (MA) count. Eyes were classified into UWFA responder or non-responder groups based on longitudinal quantitative UWFA parameter improvement. Cytokine expression was correlated with UWFA metrics and evaluated in the context of therapeutic response.

RESULTS

Twenty-one eyes were included with a mean age of 55±10 years. Increased panretinal leakage index correlated with VEGF (r=0.70, p=0.0005), angiopoietin-like 4 (r=0.77, p=4.6E-5) and interleukin (IL)-6 (r=0.64, p=0.002). Panretinal ischaemic index was associated with tissue inhibitor of metalloproteinases 1 (TIMP-1, r=0.49, p=0.03) and peripheral ischaemia correlated with VEGF (r=0.45, p=0.05). MA count correlated with increased monocyte chemotactic protein-4 (MCP-4, r=0.60, p=0.004) and platelet and endothelial cell adhesion molecule 1 (PECAM-1, r=0.58, p=0.005). Longitudinal MA reduction was associated with decreased baseline VEGF and urokinase receptor (uPAR) (p<0.05). High baseline VEGF and IL-6 were associated with dramatic reduction in macular leakage (p<0.05).

CONCLUSIONS

Baseline and longitudinal quantitative UWFA imaging parameters correlated with multiple aqueous humour cytokine concentrations, including VEGF and IL-6. Further research is needed to assess the possible implications of using these findings for evaluating treatment response.

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.

Computational Imaging Biomarker Correlation with Intraocular Cytokine Expression in Diabetic Macular Edema

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Prediction of anti-VEGF efficacy in diabetic macular oedema using intraocular cytokines and macular optical coherence tomography

PURPOSE

In eyes with diabetic macular oedema (DME), aqueous humour (AH) cytokine levels before and after anti-vascular endothelial growth factor (VEGF) treatment were compared and correlated with optical coherence tomography structural parameters.

METHODS

This prospective study included 56 control patients with cataracts and 83 patients with DME manifesting as diffuse retinal thickening (DRT), cystoid macular oedema and serous retinal detachment (SRD). AH samples were obtained before intravitreal injection of anti-VEGF or cataract surgery. VEGF, interleukin (IL)-6, IL-8, IL-10, interferon-inducible protein 10 (IP-10) and monocyte chemotactic protein 1 (MCP-1) levels were measured by multiplex bead assay. AH cytokine levels, central macular thickness (CMT), number of hyper-reflective foci (HF), continuity of external limiting membrane and ellipsoid zone (EZ) and best-corrected visual acuity were evaluated.

RESULTS

In SRD, IL-6 and MCP-1 levels and HF were increased (all p < 0.05) compared to DRT. At baseline, the number of HF was correlated with VEGF, IL-6, IL-8, IP-10 and MCP-1 (all p < 0.05). Eyes sensitive to anti-VEGF treatment had high baseline levels of VEGF, MCP-1, HF and many EZ disruptions (all p < 0.05). DME patients with normal VEGF levels but with high levels of IL-8, IP-10 and MCP-1 (all p < 0.05) had little change in CMT after anti-VEGF treatment (p = 0.678).

CONCLUSIONS

AH concentrations of some inflammatory cytokines in DME were differentially expressed among the three DME morphologies. HF was associated with VEGF and other inflammatory cytokine levels. Multiple HF at baseline predicted a significant decrease in CMT, and eyes with normal VEGF but increased inflammatory cytokines may be insensitive to anti-VEGF treatment.

Changes in aqueous and vitreous inflammatory cytokine levels in diabetic macular oedema: a systematic review and meta-analysis

Diabetic macular oedema (DME) is considered a chronic inflammatory disease associated with aberrations in many intraocular cytokines. Studies assessing the role of these cytokines as biomarkers in the diagnosis and management of DME have demonstrated inconsistent findings. We quantitatively summarized data related to 116 candidate aqueous and vitreous inflammatory cytokines as biomarkers in DME. A systematic search without year limitation was performed up to 19 October 2020. Studies were included if they provided data on aqueous or vitreous cytokine concentrations in patients with DME. Effect sizes were generated as standardized mean differences (SMDs) of cytokine concentrations between patients with DME and controls. Data were extracted from 128 studies that included 4163 study eyes with DME and 1281 control eyes. Concentrations (standard mean difference, 95% confidence interval and p-value) of aqueous IL-6 (1.28, 0.57-2.00, p = 0.004), IL-8 (1.06, 0.74-1.39, p < 0.00001), MCP-1 (1.36, 0.57-2.16, p = 0.0008) and VEGF (1.31, 1.01-1.62, p < 0.00001) and vitreous VEGF (2.27, 1.55-2.99, p < 0.00001) were significantly higher in patients with DME (n = 4163) compared to healthy controls (n = 1281). No differences, failed sensitivity analyses or insufficient data were found between patients with DME and healthy controls for the concentrations of the remaining cytokines. This analysis implicates multiple cytokine biomarker candidates other than VEGF in DME and clarifies previously reported inconsistent associations. As the therapeutic options for DME expand to include multiple agents with multiple targets, it will be critical to manage the treatment burden with tailored therapy that optimizes outcomes and minimizes treatment burden. Intraocular cytokines have the promise of providing a robust individualized assessment of disease status and response to therapy. We have identified key candidate cytokines that may serve as biomarkers in individualized treatment algorithms.

Influence of Cytokines on Inflammatory Eye Diseases: A Citation Network Study

Background: The main objective of this study was to use citation networks to analyze the relationship between different publications on the impact of cytokines at an ocular level and their authors. Furthermore, the different research areas will be identified, and the most cited publications determined. Methods: A search was performed in the Web of Science (WoS) database using the following keywords: “cytokine”, “inflammatory”, and “eye disease” for the period from 1990 to October 2021. The Citation Network Explorer and the CiteSpace software were then used to analyze the different publications. Results: 3127 publications with 8955 citations generated on the web were found. The largest number of publications on this topic emerged in 2018 and the authors with the largest number of publications addressing this area of research were Peizeng Yang (1.4%), Aize Kijlstra (1.3%), and Stephen C. Pflugfelder (1.2%). Conclusions: the citation network has provided a comprehensive and objective analysis of the main studies on the influence of cytokines in ocular inflammatory diseases.

Intravitreal Fasudil for Treatment of Diabetic Macular Edema with an Unfavorable Response

PURPOSE

This study evaluates the effect of intravitreal injection of a Rho-associated protein kinase (ROCK) inhibitor, fasudil, on diabetic macular edema (DME) with an unfavorable response.

METHODS

This study included 14 eyes of 13 patients (mean age: 65.7 ± 5.2 years) with DME, and eligible eyes underwent single intravitreal injection of 0.025 mg fasudil. The best-corrected visual acuity (BCVA), intraocular pressure (IOP), and central macular thickness (CMT) were evaluated before and 1, 2, and 3 months after treatment. The standard automated perimetry (SAP) results and maximal response of the electroretinogram (ERG) were recorded before and 3 months after treatment.

RESULTS

The BCVA, IOP, and CMT remained unchanged during the study period. Similarly, the mean deviation obtained by SAP and each ERG parameter did not show significant changes after the treatment.

CONCLUSIONS

Although single intravitreal fasudil injection failed to show therapeutic benefits in DME, it seemed to have no negative effect on the retina.

Intraocular fluid biomarkers (liquid biopsy) in human diabetic retinopathy

Purpose

This article aims to review the impact of detecting and quantifying intraocular biomarkers (liquid biopsy) in both aqueous and vitreous humor in eyes of people affected by diabetes mellitus.

Methods

This is a detailed review about aqueous and/or vitreous humor sampling in human diabetic eyes for proteomic and/or metabolomic analysis contributing to the understanding of the pathophysiology and treatment effects of diabetic retinopathy.

Results

Aqueous and vitreous humor molecular biomarkers proved to be directly correlated to each other and valuable to study retinal conditions. Moreover, proteomic and metabolomic analysis showed that the biomarkers of neuroinflammation, neurodegeneration, and vasculopathy are detectable in intraocular fluids and that their concentration changes in different stages of disease, and in response to treatment of all diabetic retinopathy aspects, mainly diabetic macular edema and proliferative retinopathy.

Conclusions

Liquid biopsy offers the possibility to improve our knowledge of intraocular eye disease induced by diabetes mellitus. The exact quantification of intraocular biomarkers contributes to the precision medicine approach even in the diabetic retinopathy scenario. The diffusion of this approach should be encouraged to have quantifiable information directly from the human model, which may be coupled with imaging data.

Effects of ranibizumab on growth factors and mediators of inflammation in the aqueous humor of patients with diabetic macular edema

PURPOSE

The study aims to investigate changes in the aqueous humor levels of 8 growth factors and inflammatory mediators after intravitreal ranibizumab injection (IRI) and the relationship between these substances and functional-morphological parameters in patients with diabetic macular edema (DME).

METHODS

We recruited 25 patients with DME who were scheduled to receive 2 doses of IRI at monthly intervals. At baseline and 1 month after IRI, we measured aqueous levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), monocyte chemoattractant protein 1 (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1), platelet-derived growth factor (PDGF)-AA, interleukin (IL)-6, IL-8, and interferon-gamma inducible protein 10 (IP-10) by the suspension array method. Central macular edema (CMT) or macular volume (MV) was examined by optical coherence tomography before and 1 month after IRI, and the improvement of macular edema was evaluated by calculating the percent change of CMT or MV.

RESULTS

Aqueous humor levels of VEGF, PlGF, PDGF-AA, and IP-10 were significantly decreased 1 month after IRI (P < 0.001, P = 0.002, P = 0.002, and P = 0.005, respectively). In addition, the baseline aqueous humor levels of PlGF, MCP-1, and IL-6 were significantly correlated with the improvement in best corrected visual acuity (P = 0.036, P = 0.024, and P = 0.049, respectively). The baseline aqueous humor level of sICAM-1 was significantly negatively correlated with the change in CMT (P = 0.005), and the baseline aqueous humor levels of VEGF and PlGF were significantly correlated with the change in MV (P = 0.020 and P = 0.003, respectively). Furthermore, the percentage reduction in VEGF after IRI was significantly correlated with the change in MV (P = 0.037).

CONCLUSIONS

Our findings suggest that the change in aqueous humor levels of VEGF, PlGF, and ICAM-1 in DME may not only be an anatomic response but also a potential therapeutic target.

CLINICAL TRIAL REGISTRATION

This study was registered in the University Hospital Medical Information Network (UMIN) clinical trial registry. The registration number is UMIN000030301.

Involvement of Cytokines in the Pathogenesis of Diabetic Macular Edema

Diabetic macular edema (DME) is a critical complication of diabetic retinopathy, a condition that arises from the breakdown of the blood–retinal barrier and the consequent increase in vascular permeability. Over the years, attempts have been made to treat DME by various approaches, including laser photocoagulation, steroid triamcinolone acetonide, and vitrectomy. However, treatment was unsatisfactory until research identified vascular endothelial growth factor (VEGF) as a factor in the pathogenesis of DME. Intraocular anti-VEGF agents show good efficacy in DME. Nevertheless, in some patients the condition recurs or becomes resistant to treatment, suggesting that other factors may be involved. Because inflammation and retinal hypoxia are seen in DME, research has examined the potential role of cytokines and other inflammatory mediators. In this review, we provide an overview of this research and describe feedback mechanisms that may represent a target for novel treatments.

Aqueous Cytokine Expression and Higher Order OCT Biomarkers: Assessment of the Anatomic-Biologic Bridge in the IMAGINE DME Study

PURPOSE

To identify biomarkers for predicting response to anti-vascular endothelial growth factor (VEGF) therapy in diabetic macular edema (DME) and evaluate any links between cytokine expression and optical coherence tomography (OCT) phenotype.

DESIGN

The IMAGINE is a post hoc image analysis and cytokine expression assessment of the Efficacy & Safety Trial of Intravitreal Injections Combined With PRP for CSME Secondary to Diabetes Mellitus (DAVE) randomized clinical trial.

METHODS

Subjects were categorized as anatomical responders or nonresponders, and within the responder group as rebounders and non-rebounders based on quantitative, longitudinal OCT criteria. Retinal layer and fluid features were extracted using an OCT machine-learning augmented segmentation platform. Responders were further sub-classified by rapidity of response. Aqueous concentrations of 54 cytokines were measured at multiple timepoints. Expression was compared between responder groups and correlated with OCT imaging biomarkers.

RESULTS

Of the 24 eyes studied, 79% were anatomical responders with 38% super responders, 17% early responders, and 25% slow responders. Twenty-one percent were nonresponders. Super responders had increased baseline vascular endothelial growth factor (VEGF) (880.0 pg/mL vs 245.4 pg/mL; P = .012) and decreased monocyte chemotactic protein-1 (MCP-1) (513.3 pg/mL vs 809.5 pg/mL; P = .0.042) concentrations compared with nonresponders. Interleukin-6 (-24.9 pg/mL vs 442.8 pg/mL; P = .032) concentrations increased among nonresponders during therapy. VEGF concentrations correlated with central subfield thickness (r = 0.49; P = .01). Panmacular retinal volume correlated with increased interleuckin-6 (r = 0.47; P = .02) and decreased MCP-1 (r = -0.45; P = .03). Matrix metallopeptidase-1 correlated with subretinal fluid volume (r = 0.50; P = .01).

CONCLUSIONS

OCT imaging biomarkers correlated with both intraocular cytokines and responsiveness to anti-VEGF therapy, which indicated a possible link to underlying pathways and their relevance to DME prognosis. Baseline concentrations of VEGF and MCP-1 are associated with anatomic response to anti-VEGF therapy.

Intravitreal ranibizumab reduced ocular blood flow and aqueous cytokine levels and improved retinal morphology in patients with diabetic macular edema

We investigated the relationship between aqueous cytokine levels, changes in ocular blood flow, and morphological and functional improvements after intravitreal ranibizumab injection (IRI) in treatment-naïve eyes with center-involving diabetic macular edema (DME). Thirty-three eligible patients with DME (33 eyes) were recruited. At the first IRI, we collected a sample of aqueous humor from each eye and measured levels of the cytokines/chemokines. Mean blur rate (MBR) was used to evaluate retinal and choroidal flow by laser speckle flowgraphy at the time of the first IRI and 1 month later. One month after IRI, both retinal and choroidal MBR had significantly decreased from baseline. The reduction ratio of the retinal MBR was significantly correlated with aqueous levels of monocyte chemotactic protein (MCP)-1 and interleukin-8, and with reduction of central macular thickness, but not with improvement of best corrected visual acuity. The reduction ratio of choroidal MBR showed no statistical correlation with any cytokine levels or changes in clinical parameters. We conclude that IRI reduces both retinal and choroidal blood flow in treatment-naïve DME. Reduction of retinal blood flow correlated with regression of morphological pathology, which is regulated by the initial aqueous levels of some cytokines.

New Insights Into Immunological Therapy for Retinal Disorders

In the twentieth century, a conspicuous lack of effective treatment strategies existed for managing several retinal disorders, including age-related macular degeneration; diabetic retinopathy (DR); retinopathy of prematurity (ROP); retinitis pigmentosa (RP); uveitis, including Behçet's disease; and vitreoretinal lymphoma (VRL). However, in the first decade of this century, advances in biomedicine have provided new treatment strategies in the field of ophthalmology, particularly biologics that target vascular endothelial growth factor or tumor necrosis factor (TNF)-α. Furthermore, clinical trials on gene therapy specifically for patients with autosomal recessive or X-linked RP have commenced. The overall survival rates of patients with VRL have improved, owing to earlier diagnoses and better treatment strategies. However, some unresolved problems remain such as primary or secondary non-response to biologics or chemotherapy, and the lack of adequate strategies for treating most RP patients. In this review, we provide an overview of the immunological mechanisms of the eye under normal conditions and in several retinal disorders, including uveitis, DR, ROP, RP, and VRL. In addition, we discuss recent studies that describe the inflammatory responses that occur during the course of these retinal disorders to provide new insights into their diagnosis and treatment.

Claudin-5 Redistribution Induced by Inflammation Leads to Anti-VEGF-Resistant Diabetic Macular Edema

Approximately 40% of patients with diabetic macular edema (DME) are resistant to anti-vascular endothelial growth factor (VEGF) therapy (rDME). Here, we demonstrate that significant correlations between inflammatory cytokines and VEGF, as observed in naive DME, are lost in patients with rDME. VEGF overexpression in the mouse retina caused delayed inflammatory cytokine upregulation, monocyte/macrophage infiltration (CD11b⁺ Ly6C⁺ CCR2⁺ cells), macrophage/microglia activation (CD11b⁺ CD80⁺ cells), and blood-retinal barrier disruption due to claudin-5 redistribution, which did not recover with VEGF blockade alone. Phosphorylated protein analysis of VEGF-overexpressed retinas revealed rho-associated coiled-coil-containing protein kinase (ROCK) activation. Administration of ripasudil, a selective ROCK inhibitor, attenuated retinal inflammation and claudin-5 redistribution. Ripasudil also contributed to the stability of claudin-5 expression by both transcriptional enhancement and degradation suppression in inflammatory cytokine-stimulated endothelium. Notably, the anti-VEGF agent and the ROCK inhibitor were synergic in suppressing cytokine upregulation, monocyte/macrophage infiltration, macrophage/microglia activation, and claudin-5 redistribution. Furthermore, in vitro analysis confirmed that claudin-5 redistribution depends on ROCK2 but not on ROCK1. This synergistic effect was also confirmed in human rDME cases. Our results suggest that ROCK-mediated claudin-5 redistribution by inflammation is a key mechanism in the anti-VEGF resistance of DME.

Correlation between anterior chamber flare changes and diabetic macular edema after intravitreal injection of ranibizumab and aflibercept

PURPOSE

To evaluate aqueous flare change patterns following anti-vascular endothelial growth factor therapy for diabetic macular edema (DME) and investigate the relationship between changes in flare values and central macular thickness (CMT).

STUDY DESIGN

Retrospective, interventional case series METHODS: A total of 84 eyes of 62 patients with DME received either intravitreal ranibizumab (IVR; n = 62) or aflibercept (IVA; n = 22). A laser flare photometer (Kowa FM500, Kowa Company, Ltd) was used to measure flare values, and CMT was assessed using optical coherence tomography. Flare values and CMT were measured prior to injection (baseline) and at, 1, 7 and 14 days after injection.

RESULTS

Flare values in the IVR group decreased significantly at day 14 (P = 0.001), whereas the IVA group showed a significant increase in flare values at day 1 (P < 0.001). In the IVA group, the baseline flare values were significantly higher in the CMT reduction group than in the non-CMT reduction group (P = 0.035). There was no correlation between changes in flare values and CMT either in the IVA or IVR group.

CONCLUSIONS

Flare value changes in patients treated with IVR decreased at day 14 post-injection. This may indicate when the most anti-inflammatory effect was obtained. There was no correlation between changes in flare values and CMT either in the IVA or IVR group; nevertheless, our research suggests that the baseline flare value is a predictive factor for the efficacy of IVA in DME.

Cytokine and Chemokine Profile Changes in Patients After Intravitreal Conbercept Injection for Diabetic Macular Edema

Purpose

This study aimed to investigate the concentrations of cytokines and chemokines in diabetic macular edema (DME) eyes before and during therapy with the intravitreal injection of conbercept (IVC) and to identify associations with disease activity.

Methods

The Bio-Plex^® 200 System and the Bio-PlexTM Human Cytokine Standard 27-Plex, Group I (Bio-Rad, Hercules, California, USA) were used to detect cytokine levels in aqueous humour. Experimental aqueous humour samples were collected from 18 patients with DME at the same time that IVC was performed at baseline and at 1 month. Control aqueous humour samples were collected from 16 patients undergoing cataract surgery.

Results

Significantly higher concentrations of vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), IL-8, eotaxin, granulocyte colony stimulating factor (G-CSF), interferon gamma-induced protein 10 (IP-10), and monocyte chemoattractant protein-1 (MCP-1) were found in the aqueous humour of DME patients than cataract patients. One month after IVC, the intraocular concentrations of VEGF were significantly lower in the eyes of DME patients than at baseline. No other cytokines were significantly altered by conbercept therapy. Best-corrected visual acuity (BCVA) slightly improved following IVC compared with that at baseline, although this difference was not significant, and central macular thickness (CMT) significantly decreased 1 month after IVC treatment.

Conclusion

Angiogenic, inflammatory and growth factors are involved in the development of DME. With the exception of VEGF, IVC did not cause significant differences in any inflammatory cytokines or growth factors in DME patients. CMT is related to VEGF levels in aqueous humour.

Usefulness of Liquid Biopsy Biomarkers from Aqueous Humor in Predicting Anti-VEGF Response in Diabetic Macular Edema: Results of a Pilot Study

The objective was to investigate the usefulness of the "liquid biopsy" of aqueous humor (AH) to predict the clinical response after intravitreal injections (IVT) of anti-VEGF agents for treating diabetic macular edema (DME). For this purpose, AH samples obtained during the first anti-VEGF IVT from 31 type two diabetic patients were analyzed. Patients were classified into three groups according to their anti-VEGF response: rapid responders (n = 11), slow responders (n = 11), and non-responders (n = 9). In addition, patients (n = 7) who showed good response to corticosteroids but a delayed or no response to anti-VEGF therapy were analyzed. Levels of 17 different cytokines, chemokines, and growth factors in AH were measured using a multiplex immunoassay. We found higher concentrations of VEGF in rapid responders to anti-VEGF therapy compared to non-responders. In addition, slow responders to anti-VEGF treatment showed higher levels of inflammatory markers than rapid responders, but did not reach statistical significance. Finally, those patients who responded to corticosteroids but not to anti-VEGF therapy showed significantly lower levels of VEGF than patients with rapid response (p = 0.01). In conclusion, "liquid biopsy" of AH could be useful to determine whether the predominant pathogenic event is primarily angiogenic or inflammatory in nature. This approach would allow physicians to select a more rational and cost-effective treatment. Further studies to validate these preliminary results are warranted.

Sub-threshold micropulse laser treatment reduces inflammatory biomarkers in aqueous humour of diabetic patients with macular edema

Subthreshold micropulse laser (SMPL) is a tissue-sparing technique whose efficacy is demonstrated for diabetic macular edema (DME) treatment. However, its mechanism of action is poorly known. A prospective observational study was performed on naïve DME patients treated with SMPL, to evaluate the changes of aqueous humor (AH) inflammatory and vaso-active biomarkers after treatments. AH samples of eighteen DME eyes were collected before and after SMPL. Ten non-diabetic AH samples served as controls. Full ophthalmic evaluation, spectral domain optical coherence tomography (SD-OCT) and fluorescein angiography were performed in DME group. Glass chip protein array was used to quantify 58 inflammatory molecules. Central retinal thickness (CRT) and visual acuity were also monitored. Several molecules showed different concentrations in DME eyes versus controls (p value < 0.05). Fas Ligand (FasL), Macrophage Inflammatory Proteins (MIP)-1α, Regulated on Activation Normal T Cell Expressed and Secreted (RANTES) and Vascular Endothelial Growth Factor (VEGF) were increased in DME at baseline versus controls and decreased after SMPL treatments (p < 0.05). CRT reduction and visual acuity improvement were also found. Inflammatory cytokines, mainly produced by the retinal microglia, were significantly reduced after treatments, suggesting that SMPL may act by de-activating microglial cells, and reducing local inflammatory diabetes-related response.

Predictor of Early Remission of Diabetic Macular Edema under As-Needed Intravitreal Ranibizumab

The early remission of diabetic macular edema (DME) often occurs in eyes treated with anti-vascular endothelial growth factor (VEGF) treatment. We retrospectively reviewed and characterized eyes with early remission of DME at six months in 80 eyes under pro re nata (PRN) intravitreal ranibizumab (IVR) injections. The number of eyes without center-involved DME gradually increased and 14 and 20 eyes achieved remission of DME at 3 or 6 months, respectively, under the PRN regimen following three monthly loading doses. In particular, eyes with early remission at 6 months had smaller CSF thickness than those without the remission before and after the treatment except at the 1-month visit (P < 0.05); however, the changes in CSF thickness did not differ between them. VA and its changes were not different between eyes with and without remission. Multivariate analysis revealed that smaller CSF thickness at baseline predicted the early remission of DME under PRN IVR injections (odds ratio, 0.989; 95% confidence interval, 0.982–0.997; P = 0.008). These data elucidate the clinical characteristics of early remission of DME under PRN IVR injections and suggest that smaller CSF thickness at baseline is a novel predictor of early remission under PRN IVR injections for DME.

Anti-Fumarase Antibody as a Predictor of Functional Efficacy of Anti-VEGF Therapy for Diabetic Macular Edema

Purpose

To evaluate whether baseline titers of anti-fumarase antibody are associated with visual prognosis after anti-VEGF treatment for diabetic macular edema (DME).

Methods

In this retrospective study, we investigated 52 eyes of 52 DME patients who received intravitreal injections of anti-VEGF drugs (ranibizumab or aflibercept) after blood sampling at baseline. Optical coherence tomography (OCT) images were obtained at every monthly visit. The serum titer of anti-fumarase antibody at baseline was measured using ELISA. We evaluated the relationship between the titer of anti-fumarase antibody at baseline and visual acuity (VA) improvement at 12 months.

Results

The serum titer of anti-fumarase IgG was related to the logMAR visual acuity (VA; R = 0.329, P = 0.017) and the disrupted ellipsoid zone (EZ; R = 0.364, P = 0.008) at baseline. The titer of this autoantibody was not associated with logMAR VA (R = -0.007, P = 0.980) but was associated with VA improvement (R = 0.465, P < 0.001) at 12 months upon anti-VEGF treatment. The transverse length of the disrupted EZ line was shortened at 12 months (P < 0.001), and restoration of the EZ line was correlated to the autoantibody titer (R = 0.396, P = 0.004) compared with the decrease in central subfield (CSF) thickness. Multivariate analysis showed that pretreatment logMAR VA (β = 0.296, P = 0.045) and the autoantibody titer (β = 0.328, P = 0.017) were associated with VA improvement after anti-VEGF treatment. In contrast, the titer was not associated with logMAR VA at 12 months.

Conclusions

Anti-fumarase antibody is a novel serum biomarker predicting better functional efficacy of anti-VEGF treatment for DME.