Aqueous humor inflammatory cytokine levels and choroidal thickness in patients with macular edema associated with branch retinal vein occlusion

Subretinal fluid in macular edema secondary to branch retinal vein occlusion

We identified characteristics of patients with subretinal fluid (SRF) in macular edema (ME) secondary to branch retinal vein occlusion (BRVO) and determined their clinical outcomes after anti-vascular endothelial growth factor (VEGF) treatment. Fifty-seven eyes of BRVO patients with ME were divided into two groups according to the presence or absence of SRF at diagnosis. We compared the aqueous profiles, ocular and systemic characteristics at baseline, and the clinical outcomes. The SRF group had significantly greater central subfield thickness (CST) values and poorer best-corrected visual acuity (BCVA) at baseline compared to the non-SRF group. The former group had significantly higher aqueous levels of interleukin-8, VEGF, and placental growth factor. CST reduction and BCVA improvement during treatment were significantly greater in the SRF group than in the non-SRF group. Consequently, CST values were significantly lower in the SRF group than in the non-SRF group at 12 months, when BCVA did not differ significantly between the two groups. The SRF group required more frequent anti-VEGF treatment over 12 months and exhibited a higher rate of macular atrophy. Based on the aqueous profiles and the number of treatments required, the presence of SRF in BRVO patients appears to be associated with higher disease activity.

The role of retinal glial cells and related factors in macular edema

Macular edema (ME) has emerged as a leading cause of visual impairment, representing a critical clinical manifestation and complication associated with many eye diseases. In the occurrence and development of ME, retinal glial cells like Müller cells and microglial cells play vital roles. Moreover, growth factor and cytokines associated with them, such as vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF), hypoxia-inducible factor-1α (HIF-1α), angiopoietin-like protein 4 (ANGPTL4), interleukin-6(IL-6), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), prostaglandin, etc., also take part in the pathogenesis of ME. Changes in these cytokines can lead to retinal angiogenesis, increased vascular permeability, blood-retinal barrier (BRB) breakdown, and fluid leakage, further causing ME to occur or deteriorate. Research on the role of retinal glial cells and related cytokines in ME will provide new therapeutic directions and effective remedies. This article is a literature review on the role of Müller cells, microglial cells and related factors in ME pathogenesis.

Emerging applications of bioinformatics and artificial intelligence in the analysis of biofluid markers involved in retinal occlusive diseases: a systematic review

PURPOSE

To review the literature on the application of bioinformatics and artificial intelligence (AI) for analysis of biofluid biomarkers in retinal vein occlusion (RVO) and their potential utility in clinical decision-making.

METHODS

We systematically searched MEDLINE, Embase, Cochrane, and Web of Science databases for articles reporting on AI or bioinformatics in RVO involving biofluids from inception to August 2021. Simple AI was categorized as logistics regressions of any type. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Tools.

RESULTS

Among 10,264 studies screened, 14 eligible articles, encompassing 578 RVO patients, met the inclusion criteria. The use and reporting of AI and bioinformatics was heterogenous. Four articles performed proteomic analyses, two of which integrated AI tools such as discriminant analysis, probabilistic clustering, and string pathway analysis. A metabolomic study used AI tools for clustering, classification, and predictive modeling such as orthogonal partial least squares discriminant analysis. However, most studies used simple AI (n = 9). Vitreous humor sample levels of interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), and aqueous humor levels of intercellular adhesion molecule-1 and IL-8 were implicated in the pathogenesis of branch RVO with macular edema. IL-6 and VEGF may predict visual acuity after intravitreal injections or vitrectomy, respectively. Metabolomics and Kyoto Encyclopedia of Genes and Genomes enrichment analysis identified the metabolic signature of central RVO to be related to lower aqueous humor concentration of carbohydrates and amino acids. Risk of bias was low or moderate for included studies.

CONCLUSION

Bioinformatics has applications for analysis of proteomics and metabolomics present in biofluids in RVO with AI for clinical decision-making and advancing the future of RVO precision medicine. However, multiple limitations such as simple AI use, small sample volume, inconsistent feasibility of office-based sampling, lack of longitudinal follow-up, lack of sampling before and after RVO, and lack of healthy controls must be addressed in future studies.

Serial choriocapillaris flow changes in eyes with branched retinal vascular obstruction (BRVO)

PURPOSE

To evaluate the choriocapillaris (CC) flow changes in branched retinal vascular obstruction (BRVO) on optical coherence tomography angiography (OCTA).

METHODS

Retrospective analysis of 29 patients with unilateral BRVO (58 eyes, including unaffected fellow eyes for controls). 4.5 x 4.5 mm macular scans were divided into 4 quadrants. Serial analyses were conducted on CC flow voids of the opposite quadrant to the active occluded area in BRVO eyes. Each of the quadrants were also compared to the occluded quadrant of resolved eyes and the contralateral quadrant of fellow eyes by matched data analysis. A regression analysis was performed on the several parameters (Choroidal thickness; CT, Choroidal vascularity index; CVI, Central macular thickness; CMT, The number of intravitreal injections) and CC flow voids.

RESULTS

The CC flow void increased sequentially: The uninvolved quadrant of acute BRVO-affected eyes, that of resolved eyes after 3-month/1-year, the contralateral quadrant of fellow eye, the involved (occluded) quadrant of resolved eyes. There were significant correlations between initial CMT, the number of injections and the CC flow void of uninvolved quadrants (P = 0.025, 0.031, respectively), and between the involved (occluded) quadrants and fellow CT (P = 0.029).

CONCLUSION

CC flow void of uninvolved macular areas decreased significantly in eyes with acute BRVO, suggesting that CC changes were limited to the blocked area and a compensatory mechanism would work in surrounding areas.

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.

Metabolite Changes in the Aqueous Humor of Patients With Retinal Vein Occlusion Macular Edema: A Metabolomics Analysis

Macular edema (ME) is the main cause of visual impairment in patients with retinal vein occlusion (RVO). The degree of ME affects the prognosis of RVO patients, while it lacks objective laboratory biomarkers. We aimed to compare aqueous humor samples from 28 patients with retinal vein occlusion macular edema (RVO-ME) to 27 age- and sex-matched controls by ultra-high-performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry, so as to identify the key biomarkers and to increase the understanding of the mechanism of RVO-ME at the molecular level. Through univariate and multivariate statistical analyses, we identified 60 metabolites between RVO-ME patients and controls and 40 differential metabolites in mild RVO-ME [300 μm ≤ central retinal thickness (CRT) < 400 μm] patients compared with severe RVO-ME (CRT ≥ 400 μm). Pathway enrichment analysis showed that valine, leucine, and isoleucine biosynthesis; ascorbate and aldarate metabolism; and pantothenate and coenzyme A biosynthesis were significantly altered in RVO-ME in comparison with controls. Compared with mild RVO-ME, degradation and biosynthesis of valine, leucine, and isoleucine; histidine metabolism; beta-alanine metabolism; and pantothenate and coenzyme A biosynthesis were significantly changed in severe RVO-ME. Furthermore, the receiver operating characteristic (ROC) curve analysis revealed that adenosine, threonic acid, pyruvic acid, and pyro-L-glutaminyl-l-glutamine could differentiate RVO-ME from controls with an area under the curve (AUC) of >0.813. Urocanic acid, diethanolamine, 8-butanoylneosolaniol, niacinamide, paraldehyde, phytosphingosine, 4-aminobutyraldehyde, dihydrolipoate, and 1-(beta-D-ribofuranosyl)-1,4-dihydronicotinamide had an AUC of >0.848 for distinguishing mild RVO-ME from severe RVO-ME. Our study expanded the understanding of metabolomic changes in RVO-ME, which could help us to have a good understanding of the pathogenesis of RVO-ME.

Treatment Results of Bevacizumab for Macular Edema Secondary to Branch Retinal Vein Occlusion

Purpose: To evaluate the results of treatment according to the method of intravitreal injection of bevacizumab for macular edema due to branch retinal vein occlusion (BRVO). Methods: The clinical records of macular edema patients were analyzed retrospectively for a total of 62 eyes of 62 patients who were injected with bevacizumab into the vitreous as the first treatment for BRVO. Best-corrected visual acuity (BCVA), the findings of spectral-domain optical coherence tomography before and after injection, and prognosis-related factors were evaluated for 21 eyes that received the initial three monthly loading treatments and the 41 eyes that did not. Results: Significant improvement in BCVA was observed in the group having received the initial three injections compared with the group who did not receive the injections at 3, 6, and 12 months (<i>p</i> = 0.025, <i>p</i> = 0.019, and <i>p</i> = 0.008, respectively). The central macular thickness (CMT) showed greater improvement in the initial three injections group than the group without at 6 months (<i>p</i> = 0.034). Multivariate regression showed that the duration from the onset, the three loadings, BCVA, disorganization of the retinal inner layer (DRIL), and choroidal thickness were predictors related to visual gain (<i>p</i> = 0.044, <i>p</i> = 0.047, <i>p</i> = 0.004, <i>p</i> = 0.045, and <i>p</i> = 0.034, respectively). Age, three loadings, BCVA, and DRIL were predictors related to final visual acuity (<i>p</i> = 0.045, <i>p</i> = 0.046, <i>p</i> = 0.002, and <i>p</i> = 0.034, respectively). Duration from the onset, CMT, and choroidal thickness were predictors related to CMT improvement (<i>p</i> = 0.042, <i>p</i> = 0.009, and <i>p</i> = 0.015, respectively). Conclusions: In macular edema of BRVO, the initial three monthly intravitreal injections of bevacizumab provided superior treatment outcomes regarding short-term functional and anatomical improvements and long-term functional improvement, compared with methods that did not treat with the initial three monthly injections.

Factors affecting resolution of subretinal fluid after selective retina therapy for central serous chorioretinopathy

The purpose of this study was to investigate the factors of clinical outcome of selective retina therapy (SRT) for central serous chorioretinopathy (CSC). This retrospective study included 77 eyes of 77 patients, who were treated with SRT for CSC and observed at least 6 months after the treatment. SRT laser (527 nm, 1.7 µs, 100 Hz) was used for treatment. The mean best-corrected visual acuity (logMAR), central macular thickness (CMT) and central choroidal thickness were changed from baseline to at 6-months follow-up with significant difference. The multivariate analyses found that the rate of change (reduction) in CMT was associated with focal leakage type on fluorescein angiography (FA) (p = 0.03, coefficient 15.26, 95% confidence interval 1.72–28.79) and larger baseline CMT (p < 0.01, coefficient − 0.13, 95% confidence interval − 0.13 to − 0.05). Complete resolution of subretinal fluid was associated with nonsmoking history (p = 0.03, odds ratio 0.276, 95% confidence interval 0.086–0.887) and focal leakage type on FA (p < 0.01, odds ratio 0.136, 95% confidence interval 0.042–0.437). These results may be useful for predicting the therapeutic effectiveness of SRT.