Changes in Aqueous Cytokine Levels Following Intravitreal Aflibercept in Treatment-Naive Patients with Diabetic Macular Edema

The Change of Aqueous Humor Cytokine Levels after Anti-VEGF in Diabetic Macular Edema: A Systematic Review and Meta-Analysis

Background

Diabetic macular edema (DME) is a vision-threatening complication that severely impairs vision, and VEGF has a certain improvement effect on it as a growth factor.

Objective

To assess the alterations of different aqueous humor cytokine concentrations after intravitreal antivascular endothelial growth factor (VEGF) treatment for diabetic macular edema (DME).

Methods

We searched PubMed, EMBASE, and the Cochrane Library from inception up to May 2022 for studies evaluating the alterations of different aqueous humor cytokine concentrations after intravitreal anti-VEGF treatment for diabetic macular edema. The estimates from eligible studies were meta-analyzed by the Hartung-Knapp/Sidik-Jonkman random-effects method. Egger's regression test was used to determine the publications' bias. A 95% confidence interval was calculated across studies. The analysis was performed using STATA™ Version 15 software.

Results

Nine eligible studies involving a total of 209 eyes for our systematic review were identified through our search strategy. The mean differences in 1-month and 2-month changes of VEGF were 110.681 pg/ml (P < 0.001) and 283.474 pg/ml (P=0.003), respectively. The mean difference in 2-month changes of interleukin 6 (IL-6) was -24.784 pg/ml (P=0.037). The mean difference in 3-month changes of central macular thickness was 130.372 μm (P < 0.001).

Conclusions

Intravitreal injection of anti-VEGF exerts a protective effect on macular edema secondary to diabetic retinopathy by affecting various cytokine concentrations, especially reducing aqueous VEGF concentrations and interleukin 6 in patients with DME.

Vitreous Inflammatory Cytokines and Chemokines, Not Altered After Preoperative Adjunctive Conbercept Injection, but Associated With Early Postoperative Macular Edema in Patients With Proliferative Diabetic Retinopathy

Purpose

To investigate the influence of preoperative adjunctive anti-VEGF drug (Conbercept) on vitreous inflammatory cytokines and chemokines profiles and whether those cytokines were associated with early macular edema (ME) after surgery for patients with proliferative diabetic retinopathy (PDR).

Methods

In this post hoc analysis of the CONCEPT clinical trial, subjects with PDR underwent vitrectomy were included and vitreous samples were collected at the start of vitrectomy. Levels of vitreous VEGF, 17 inflammatory cytokines, and 11 chemokines were measured using Luminex multiplex technology. Subjects were then divided into groups based on with (Pre-IV) or without (No-Pre-IV) preoperative intravitreous injection of Conbercept; with or without early ME after surgery.

Results

There was no difference between Pre-IV (13/30) and No-Pre-IV (7/29) concerning the ratio of patients with early ME (p = 0.17). After preoperative intravitreous injection of Conbercept, VEGF level dramatically decreased (p = 0.001), TNF-α (p = 0.002), and IP-10 (p = 0.018) increased in Pre-IV group. In patients with early ME after surgery, however, a number of cytokines increased, including IL-1β (p = 0.008), IL-2 (p = 0.023), IL-4 (p = 0.030), IL-9 (p = 0.02), IL-10 (p = 0.002), IL-12 (p = 0.001), IL-13 (p = 0.031), IL-17A (p = 0.008), TNF-α (p = 0.012), CXCL9 (p = 0.023), G-CSF (p = 0.019), MCP-1 (p = 0.048), and RANTES (p = 0.016).

Conclusion

We found the preoperative adjunctive Conbercept injection has limited influence on the levels of vitreous inflammatory cytokines and chemokines in PDR. The elevated levels of a series of cytokines might be associated with early inflammation after vitrectomy, which may lead to postoperative ME.

Short-Term Efficacy in Polypoidal Choroidal Vasculopathy Patients Treated With Intravitreal Aflibercept or Conbercept

Purpose

To compare the short-term efficacy in patients with polypoidal choroidal vasculopathy (PCV) treated using either aflibercept or conbercept.

Methods

This prospective study included 41 patients with treatment-naive PCV (42 eyes). All the patients were treated with either aflibercept or conbercept using an initial series of 3 monthly loading injections. Changes in the best-corrected logMAR visual acuity (BCVA) and anatomic outcomes were evaluated at 3 months.

Results

BCVA was improved with reduction in central choroidal thickness (CCT), central foveal thickness (CFT), and subretinal fluid (SRF) after 3 monthly loading injections in both aflibercept (IVA) and conbercept (IVC) groups. There was no significant difference in either visual or anatomic outcomes between the two groups after 3 months of treatment. However, compared with the IVC group, significantly higher BCVA improvement was observed in the patients in the IVA group with baseline BCVA better than 1. A visual outcome improved ≥3 lines in 13 patients in the IVA group (59%), and 9 patients in the IVC group (45%). A relatively high proportion of polyp regression was observed in the IVA group (63%) compared with the IVC group (55%) via OCTA.

Conclusions

Visual and anatomic outcomes were significantly improved in both IVA and IVC groups, but the results suggest a potentially superior short-term response in the IVA group.

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.

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.