Cytokines and Pathogenesis of Central Retinal Vein Occlusion

Hybrid Biomembrane-Functionalized Nanorobots Penetrate the Vitreous Body of the Eye for the Treatment of Retinal Vein Occlusion

Intravitreal injections of antivascular endothelial growth factor (VEGF) agents are the primary method for treating retinal vein occlusion (RVO). However, the complex structure of eye anatomy presents ocular barriers that impede drug delivery. Additionally, these drugs only manage the complications associated with RVO and fail to address the underlying cause of vessel occlusions. Here, we describe a method that utilizes functionalized magnetically driven nanorobots to overcome ocular barriers and treat RVO. These nanorobots are developed using a hybrid biomembrane that combines stem cell membranes with liposome-derived membranes, enveloping perfluorohexane, iron oxide nanoparticles, and l-arginine. After intravitreal injection, the nanorobots can move directionally through and penetrate the vitreous body to reach the retina, driven by an external magnetic field. Subsequently, the nanorobots actively target the inflammation sites at occluded vessels due to the presence of stem cell membranes. In a rat model of RVO, enhanced targeting and accumulation in ischemic retinal vessels were demonstrated following intravitreal injections. Furthermore, the application of ultrasound triggers the release of l-arginine at the site of occlusion, stimulating the production of nitric oxide, which promotes vasodilation and restores blood flow, thereby achieving excellent therapeutic efficacy for RVO. We believe these methods hold significant promise for overcoming challenges in ocular drug delivery and effectively treating RVO in clinical applications.

Ophthalmologic toxicities of antineoplastic agents in genitourinary cancers: Mechanisms, management, and clinical implications

Genitourinary cancers affect over 480,000 patients in the United States annually. While promising therapeutic modalities continue to emerge, notably immune checkpoint inhibitors, molecular targeted therapies, antibody-drug conjugates, and radioligand therapies, these treatments are associated with a spectrum of adverse side-effects, including ophthalmologic toxicities. In this review, we cover the most commonly used antineoplastic agents for the kidneys, bladder, urinary tracts, prostate, testis, and penis, detailing mechanism, indication, and recent trials supporting their use. For each category of antineoplastic therapy, we describe the epidemiology, management, and clinical presentation, of common ophthalmologic toxicities stemming from these agents. This review serves to augment awareness and recognition of possible ophthalmologic manifestations resulting from the use of antineoplastic agents in genitourinary malignancy. Early identification of these side effects can hasten ophthalmology referral and ultimately improve visual outcomes in patients experiencing medication-induced ocular toxicities.

Dynamic Complement Protein Changes in Aqueous Humor and Plasma of Patients With Retinal Vein Occlusion During Ranibizumab Treatment

Purpose

To assess dynamic changes of complement protein in aqueous humor (AH) and plasma of retinal vein occlusion (RVO) patients during ranibizumab treatment, and to explore the differential expression of complement proteins in branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).

Patients and Methods

This prospective, consecutive case series study collected AH and plasma samples from 27 RVO patients at baseline, 1 and 2 months after ranibizumab treatment, including 19 BRVO and 8 CRVO patients. The concentrations of 13 complement proteins and vascular endothelial growth factor A (VEGF-A) were measured using Luminex® × MAP® technology.

Results

During ranibizumab treatment, a reduction in the levels of C1q (p < 0.001), C2 (p = 0.030), C4 (p = 0.001), C4b (p = 0.026), C3b/iC3b (p < 0.001), C5 (p = 0.007), C5a (p = 0.005), CFD (p = 0.022), CFH (p < 0.001), and CFI (p < 0.001) in AH was observed. No significant changes were observed in the plasma levels of all measured factors. At baseline, CRVO had higher levels of C4 (p = 0.003), C4b (p < 0.001), C3b/iC3b (p < 0.001), C5 (p = 0.020), C5a (p = 0.007), CFD (p = 0.002), CFH (p < 0.001), and CFI (p < 0.001) in AH compared to BRVO.

Conclusion

Ranibizumab treatment reduced the intraocular but not circulating activation of classical and alternative complement pathways in RVO patients. Differences in intraocular complement proteins were observed between BRVO and CRVO patients, which may reflect different pathogenesis.

Effectiveness and cytokine profile of combined anti-vascular endothelial growth factor and corticosteroid therapy for chronic retinal vein occlusion

PURPOSE

To investigate whether sub-Tenon injection of triamcinolone acetonide (STTA) combined with anti-vascular endothelial growth factor (VEGF) prolongs the recurrence intervals of macular edema (ME) for chronic retinal vein occlusion (RVO) and to investigate the differences in intraocular inflammatory cytokines between good responders (GRs) and non-responders (NRs).

METHODS

This retrospective, observational study involved 42 eyes of 42 patients with ME due to chronic RVO who had received only anti-VEGF for ≥ 1 year and were transitioned to combination therapy. GRs were defined as patients whose recurrence intervals were prolonged by ≥ 2 weeks compared with patients receiving anti-VEGF alone. Moreover, immediately before starting the combined therapy, aqueous humor was collected and the following inflammatory cytokines were compared between GRs and NRs: CCL11, MCP-3, IP-10, CCL13, G-CSF, GM-CSF, IL-1α, IL-15, IL-4, M-CSF, MMP-9, TNF-α, MCP-1, CXCL-1, CXCL12, IL-8, galectin-1, IFN-γ, IL-12, IL-2, IL-6, MMP-1, PDGF-AA, and VEGF-A. These results were analyzed by nominal logistic regression after stepwise variable selection.

RESULTS

There were 26 eyes (62%) in the GR group. Nominal logistic analyses showed that a higher concentration of IL-1α (P = 0.016) and lower concentrations of IL-5 (P = 0.015), IL-6 (P = 0.022), and galectin-1 (P = 0.015) were significantly associated with the extension of the time from injection to recurrence of ME.

CONCLUSION

Combined anti-VEGF and STTA therapy for chronic RVO was effective in 62% of patients, suggesting the effectiveness of STTA. Higher IL-1α and lower IL-5, IL-6, and galectin-1 were the factors associated with combined treatment effectiveness.

Choroidal and Retinal Blood Flow Changes Following Vitrectomy in Two Cases of Postoperative Endophthalmitis

Postoperative endophthalmitis is a rare but potentially vision-threatening complication following intraocular surgery. We report two cases (one acute onset and one delayed onset) of postoperative endophthalmitis treated with vitrectomy, in which ocular circulation was quantitatively monitored using laser speckle flowgraphy (LSFG). Both cases presented with vitreous opacity, hypopyon, and markedly reduced visual acuity. LSFG measurements demonstrated progressive improvement in both choroidal and retinal blood flow parameters after treatment, accompanied by a reduction in choroidal thickness. These circulatory changes correlated with visual recovery following treatment. Our findings suggest that LSFG may serve as a useful tool for monitoring therapeutic response and predicting visual outcomes in postoperative endophthalmitis.

Drug-induced retinal vein occlusion: a disproportionality analysis from the FDA adverse event reporting system (2004-2023)

Introduction

Retinal vein occlusion (RVO) often causes irreversible visual impairment, making early prevention crucial. This study aims to identify associations between different medications and RVO and provide information for clinical practice.

Method

This study included reports of RVO from the FDA Adverse Event Reporting System (FAERS) database from the first quarter (Q1) of 2004 to the fourth quarter (Q4) of 2023. The reported drugs were analyzed for adverse drug reaction (ADR) signals using four disproportionality algorithms. Kaplan-Meier curves and median time to onset were used to evaluate the drugs.

Results

From 2004 to 2023, the FAERS database recorded 6,151 reports associated with RVO. Disproportionality analyses identified 25 drugs significantly associated with RVO. Mirabegron showed the highest risk signal, followed by Raloxifene, Tadalafil, Fingolimod, and Bimatoprost. These high-risk drugs are distributed across different therapeutic areas, including urogenital system and sex hormones, ophthalmic drugs, nervous system drugs, musculoskeletal system drugs, anti-tumor and immune-modulating drugs, and anti-parasitic drugs. Specific drug targets such as adrenergic receptor agonists, hormone regulators, and PDE5 inhibitors were identified as high risk. Ophthalmic drugs exhibited the longest median time to adverse ocular reactions at 532.01 days, followed by anti-parasitic drugs, nervous system drugs, urogenital system and sex hormone drugs, anti-tumor and immune-modulating drugs, and musculoskeletal system drugs.

Conclusion

This study provides an overview of drug-induced RVO, identifying potential culprit drugs and their distribution characteristics. These findings enhance understanding of medication safety and help optimize clinical practice.

Long term efficacy and safety profile of dexamethasone intravitreal implant in retinal vein occlusions: a systematic review

Background/objective

Retinal vein occlusion (RVO) is a common, sight-threatening vascular disorder affecting individuals of all ages, with incidence increasing with age. Due to its complex, multifactorial nature, treating RVO remains a clinical challenge. Currently, treatment strategies include laser photocoagulation (especially for branch RVO), anti-VEGF therapies, and intravitreal corticosteroids. This systematic review (without meta-analysis) aimed to update the evidence on the efficacy and safety of the sustained-release intravitreal dexamethasone implant (DEX-i) in managing macular edema (ME) secondary to central and branch RVO.

Methods

A systematic review was conducted to assess current literature on DEX-i for ME secondary to RVO. Relevant studies were analyzed for outcomes related to visual acuity, retinal thickness, and the safety profile of DEX-i in RVO treatment.

Results

Evidence indicates that DEX-i substantially improves best-corrected visual acuity (BCVA) and reduces central retinal thickness (CRT) in ME associated with both branch and central RVO, demonstrating rapid and sustained effects. Common adverse events associated with DEX-i included manageable complications, such as medically controlled intraocular pressure elevation and progression of cataracts.

Conclusion

DEX-i offers effective and sustained improvements in both visual and anatomical outcomes for patients with ME secondary to RVO. Individualized treatment selection is essential to optimize patient outcomes. Future directions include identifying predictive biomarkers and adopting patient-centered approaches based on individual clinical characteristics, which may enhance treatment success in RVO.

Baicalin alleviates the injury of human retinal pigment epithelium cells and improves branch retinal vein occlusion in rats by inhibiting the HIF-1α/VEGFA axis

BACKGROUND

At present, relevant studies have found that baicalin can improve macular edema (ME) caused by glaucoma, but the effect on branch retinal vein occlusion (BRVO) is still unclear.

METHODS

The CoCl2-stimulated ARPE-19 cells were treated with different concentrations of baicalin and detected cell viability, apoptosis and oxidative stress. Next, the hypoxia-inducible factor-1α (HIF-1α) overexpression vector or siRNA were transfected into CoCl2-stimulated ARPE-19 cells, and the cell changes were detected. We searched the potential binding proteins of HIF-1α through the online database, and screened vascular endothelial growth factor A (VEGFA) as the research object. The CoCl2-stimulated ARPE-19 cells were treated with baicalin alone, or transfected with HIF-1α overexpression vector, or transfected with HIF-1α overexpression vector and VEGFA siRNA, and the cell changes were detected. Finally, we verified the therapeutic effect of baicalin on BRVO rats in vivo.

RESULTS

Baicalin inhibited CoCl2-induced apoptosis, inflammation and oxidative stress in ARPE-19 cells, and baicalin inhibited HIF-1α protein expression. In CoCl2-induced hypoxia cells, HIF-1α aggravated apoptosis, inflammation and oxidative stress, while HIF-1α silencing alleviated cell damage. Mechanism study showed that in baicalin-treated CoCl2-induced cells, VEGFA protein expression decreased and cell damage was improved, but this protective effect was counteracted by HIF-1α, and VEGFA silencing again inhibited apoptosis, inflammation and oxidative stress. Baicalin inhibited HIF-1α and VEGFA protein expression in the retinal tissue of BRVO rats, reduced injury, and promoted the recovery of ganglion cell layer.

CONCLUSIONS

Baicalin alleviated ARPE-19 cell injury and improved BRVO in rats by inhibiting HIF-1α/VEGFA axis in vivo and in vitro.

Integrated Assessment of OCT, Multimodal Imaging, and Cytokine Markers for Predicting Treatment Responses in Retinal Vein Occlusion Associated Macular Edema: A Comparative Review of Anti-VEGF and Steroid Therapies

Retinal vein occlusion (RVO) is a significant cause of vision loss, characterized by the occlusion of retinal veins, leading to conditions such as central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO). Macular edema (ME), a prevalent consequence of RVO, is the primary cause of vision impairment in affected patients. Anti-VEGF agents have become the standard treatment, showing efficacy in improving visual acuity (VA) and reducing ME. However, a subset of patients exhibit a suboptimal response to anti-VEGF therapy, necessitating alternative treatments. Corticosteroids, which address inflammatory pathways implicated in ME, have shown promise, particularly in cases resistant to anti-VEGF. This review aims to identify biomarkers that predict treatment response to corticosteroids in RVO-associated ME, utilizing multimodal imaging and cytokine assessments. Baseline imaging, including SD-OCT and OCT-A, is essential for evaluating biomarkers like hyperreflective foci (HRF), serous retinal detachment (SRF), and central retinal thickness (CRT). Elevated cytokine levels, such as IL-6 and MCP-1, correlate with ME severity and poor anti-VEGF response. Early identification of these biomarkers can guide timely transitions to corticosteroid therapy, potentially enhancing treatment outcomes. The practical conclusion of this review is that integrating biomarker assessment into clinical practice enables personalized treatment decisions, allowing for earlier and more effective management of RVO-associated ME by transitioning patients to corticosteroid therapy when anti-VEGF agents are insufficient. Advanced diagnostics and machine learning may further refine personalized treatment strategies, improving the management of RVO-associated ME.

Deciphering the interplay of gut microbiota and metabolomics in retinal vein occlusion

This study aims to explore the link between retinal vein occlusion (RVO), a blinding ocular condition, and alterations in gut microbiota composition, to offer insights into the pathogenesis of RVO. Fecal samples from 25 RVO patients and 11 non-RVO individuals were analyzed using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC-MS). Significant differences in the abundance of gut microbial species were noted between RVO and non-RVO groups. At the phylum level, the RVO group showed an elevation in the ratio of Firmicutes to Bacteroidetes. At the genus level, the RVO group showed higher abundance in Escherichia_Shigella (P < 0.05) and less abundance in Parabacteroides (P < 0.01) than the non-RVO group. Functional predictions indicated reduced folate synthesis, biotin metabolism, and oxidative phosphorylation, with an increase in butyric acid metabolism in the RVO group. LC-MS analysis showed significant differences in purine metabolism, ABC transporters, and naphthalene degradation pathways, especially purine metabolism. Pearson correlation analysis revealed significant associations between bacterial genera and fecal metabolites. Enrichment analysis highlighted connections between specific metabolites and bacterial genera. The findings showed that the dysregulation of gut microbiota was observed in RVO patients, suggesting the gut microbiota as a potential therapeutic target. Modulating the gut microbiota could be a novel strategy for managing RVO and improving patient outcomes. Furthermore, the study findings suggest the involvement of gut microbial dysbiosis in RVO development, underscoring the significance of understanding its pathogenesis for effective treatment development.

IMPORTANCE

Retinal vein occlusion (RVO) is a blinding ocular condition, and understanding its pathogenesis is crucial for developing effective treatments. This study demonstrates significant differences in gut microbiota composition between RVO patients and non-RVO individuals, implicating the involvement of gut microbial dysbiosis in RVO development. Functional predictions and metabolic profiling provide insights into the underlying mechanisms, highlighting potential pathways for therapeutic intervention. These findings suggest that modulating the gut microbiota might be a promising strategy for managing RVO and improving patient outcomes.

The role of adiponectin and its receptor signaling in ocular inflammation-associated diseases

Ocular inflammation-associated diseases are leading causes of global visual impairment, with limited treatment options. Adiponectin, a hormone primarily secreted by adipose tissue, binds to its receptors, which are widely distributed throughout the body, exerting powerful physiological regulatory effects. The protective role of adiponectin in various inflammatory diseases has gained increasing attention in recent years. Previous studies have confirmed the presence of adiponectin and its receptors in the eyes. Furthermore, adiponectin and its analogs have shown potential as novel drugs for the treatment of inflammatory eye diseases. This article summarizes the evidence for the interplay between adiponectin and inflammatory eye diseases and provides new perspectives on the diagnostic and therapeutic possibilities of adiponectin.

Prevalence and risk factors of retinal vein occlusion in individuals with diabetes: The kailuan eye study

PURPOSE

The aim of this study was to analyze the incidence of retinal vein occlusion (RVO) in patients with and without diabetes in the population and compare the influencing factors.

METHOD

The community-based Kailuan Eye Study included 14,440 participants (9835 male, 4605 female) with a mean age of 54.0 ± 13.3 years (range, 20-110 years). They underwent a systemic and ophthalmologic examination. RVO were diagnosed on fundus photographs.

RESULT

By matching for age and gender, we included a total of 2767 patients each with diabetes and non-diabetes. The prevalence of RVO among patients with and without diabetes was 1.5% and 0.8%, respectively. The prevalence of RVO was higher in patients with diabetes than in patients without diabetes in all age groups. Multifactorial regression analysis showed that only fasting blood glucose levels were significantly different between patients with RVO with or without DM. The occurrence of RVO in the group with diabetes was mainly associated with higher fasting glucose and systolic blood pressure; in the group without diabetes, RVO was mainly associated with higher diastolic blood pressure, Body Mass Index, and lower low-density lipoprotein cholesterol levels.

CONCLUSION

We found that patients with diabetes have increased risks of RVO. In addition to blood pressure control, we recommend educating patients with diabetes about RVO, to prevent its subsequent occurrence.

Could Triglyceride-Glucose Index, a Predictor of Atherosclerosis, Be Associated with Retinal Vein Occlusion?

Objectives

The triglyceride-glucose (TyG) index is a sign of atherosclerosis in cardiovascular diseases. The TyG index is thought to have clinical significance for the assessment of vascular damage. In this study we aimed to demonstrate the connection between the TyG index and retinal vein occlusion (RVO).

Materials and Methods

This case-control observational study involved 492 participants aged 40-90, admitted to the ophthalmology outpatient clinic of our hospital. TyG index was calculated using the formula: ln(fasting TG [mg/dL] × fasting plasma glucose [mg/dL]/2).

Results

The RVO group included 387 patients (181 women and 206 men) and the control group included 115 patients (61 women and 54 men). The average patient age was 62.9±11.1 years in the RVO group and 56.7±8.7 years in the control group. The TyG index was higher in the RVO group (8.9±0.7) than in the control group (8.8±0.6). This difference was statistically significant (p=0.04). The correlation was statistically significant when evaluated according to age and sex by multivariate logistic regression analysis (odds ratio: 1.45, confidence interval: 1.03- 2.02, p=0.03).

Conclusion

The TyG index is a novel atherogenicity index that is derived from routine blood tests and can be used to determine the risk of RVO in at-risk individuals with a simple calculation. Therefore, the TyG index could help as a reliable guide to identify individuals at RVO with high risk and initiate early intervention.

Investigation into safflower injection as a prophylactic treatment for retinal vein occlusion in a rabbit model

The study aimed to assess the effect and mechanism of safflower injection in preventing retinal vein thrombosis in rabbits. Twenty healthy adult pigmented rabbits were randomly assigned to either the experimental group, receiving safflower injection, or the control group, receiving normal saline. After two weeks of treatment, blood samples were collected to analyze platelet adhesion and aggregation rates. Photodynamic therapy was applied to induce occlusion in the target retinal vein. Fundus photography and fluorescein angiography were recorded using a dynamic microscopic monitoring system, and laser speckle imaging was employed to assess blood flow in the affected vein. The experimental group exhibited significantly lower rates of platelet adhesion and aggregation compared to the control group. Following the induction of retinal vein occlusion, the experimental group showed a lower complete occlusion rate of the target retinal vein. Although initial blood flow in the target vein was similar between groups, the blood flow at 1, 3, and 5 min post-occlusion was significantly higher in the experimental group. Safflower injection delayed retinal vein thrombosis formation, preserved blood flow in the affected retinal area, and reduced platelet adhesion and aggregation. These effects facilitated vascular reperfusion within a limited timeframe.

Role of Novel Inflammatory Factors in Central Retinal Vein Occlusion with Macular Edema

Background and Objectives: To investigate associations among the aqueous humor levels of novel inflammatory factors, including FMS-related tyrosine kinase 3 ligand (Flt-3L), fractalkine, CXC chemokine ligand 16 (CXCL-16), and endocan-1; the severity of macular edema in central retinal vein occlusion (CRVO); and the prognosis of CRVO with macular edema after antivascular endothelial growth factor (VEGF) therapy. Materials and Methods: Aqueous humor was obtained during anti-VEGF treatment with intravitreal ranibizumab injection (IRI) in patients with CRVO and macular edema (n = 19) and during cataract surgery in patients with cataracts (controls, n = 20), and the levels of VEGF and novel inflammatory factors were measured. Macular edema was evaluated by central macular thickness (CMT) and neurosensory retinal thickness (TNeuro), and improvement was evaluated by calculating the percentage change in CMT and TNeuro from before to 1 month after IRI. Results: The levels of VEGF and the novel inflammatory factors were significantly higher in the CRVO group, and the levels of Flt-3L, CXCL-16, and endocan-1 were significantly correlated with each other and with the aqueous flare value. Baseline levels of Flt-3L, CXCL-16, and endocan-1 had a significantly negative correlation with the change in CMT, and the baseline level of CXCL-16 was significantly negatively correlated with the change in TNeuro. Conclusions: Relations among novel inflammatory factors should be further investigated. These findings may help improve understanding of macular edema in CRVO patients and aid the development of new treatments targeting novel inflammatory factors.

Assessment of systemic inflammatory response index and other inflammatory indicators in retinal vein occlusion

Retinal vein occlusion (RVO) is the second most common retinal vascular disease after diabetic retinopathy. The study aimed to evaluate the association and the predictive value of inflammatory indicators in RVO. Sixty patients with RVO and 60 healthy individuals were enrolled in this retrospective study. Inflammatory indicators and other hematological parameters obtained from the peripheral venous sample were analyzed and compared among groups. White blood cell count (P = .003), neutrophil (P < .001), neutrophil-to-lymphocyte ratio (NLR) (P < .001), monocyte-to-lymphocyte ratio (MLR) (P < .001), platelet-to-lymphocyte ratio (PLR) (P = .014), systemic immune-inflammation index (SII) (P < .001), and systemic inflammatory response index (SIRI) (P < .001) were significantly higher; the lymphocyte count (P < .001) was significantly lower in patients with RVO. According to receiver operating characteristic analysis, NLR was significant at the good level (area under the curve [AUC] = 0.817, P < .001); SIRI, SII, and MLR were significant at the fair level (AUC = 0.774, P < .001; AUC = 0.733, P < .001, and AUC = 0.724, P < .001, respectively) and PLR (AUC = 0.630, P = .014) was significant at the weak level in terms of RVO prediction. SIRI was superior to other indicators, except NLR, to predict RVO. SIRI, NLR, SII, MLR, and PLR can be used as predictors for identifying the risk of RVO.

Oxidative stress in the eye and its role in the pathophysiology of ocular diseases

Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.

Therapeutic potential of iron chelators in retinal vascular diseases

Iron is one of the necessary metal elements in the human body. There are numerous factors that control the balance of iron metabolism, and its storage and transportation mechanisms are intricate. As one of the most energy-intensive tissues in the body, the retina is susceptible to iron imbalance. The occurrence of iron overload in the retina leads to the generation of a significant quantity of reactive oxygen species. This will aggravate local oxidative stress and inflammatory reactions and even lead to ferroptosis, eventually resulting in retinal dysfunction. The blood-retina-retinal barrier is eventually harmed by oxidative stress and elevated inflammation, which are characteristics of retinal vascular disorders. The pathophysiology of retinal vascular disorders may be significantly influenced by iron. Recently, iron-chelating agents have been found to have antioxidative and anti-inflammatory actions in addition to iron chelating. Therefore, iron neutralization is considered to be a new and potentially useful therapeutic strategy. This article reviews the iron overload in retinal vascular diseases and discusses the therapeutic potential of iron-chelating agents.

Sleep-disordered breathing is related to retinal vein occlusion: A meta-analysis

BACKGROUND

Previous studies suggest that sleep-disordered breathing (SDB) may be a potential risk factor of retinal vein occlusion (RVO). We conducted a meta-analysis to systematically explore the relationship between RVO and SDB.

METHODS

Observational studies assessing the relationship between SDB and RVO were retrieved by searches of electronic databases including the PubMed, Embase, Web of Science, China National Knowledge Infrastructure, and Wan Fang databases from database inception to August 9, 2023. In consideration of intra-study heterogeneity, a random-effects model was adopted to combine the results.

RESULTS

Seven studies (1 retrospective cohort and 6 case-control studies) were included in this meta-analysis, and among 36,628 adults included in those studies, 6452 (17.6%) had SDB. The combined results indicated that SDB was associated with RVO [risk ratio (RR): 1.92, 95% confidence interval (CI): 1.60-2.30, P < .001] with no significant heterogeneity (I2 = 0%). Subgroup analyses showed consistent relationships between SDB and any RVO (RR: 1.73, 95% CI: 1.13-2.28, P < .001), central RVO (RR: 2.20, 95% CI: 1.57-3.08, P < .001), and branch RVO (RR: 1.85, 95% CI: 1.15-2.99, P = .01). Moreover, the relationship was consistent among patients with mild (RR: 1.82, 95% CI: 1.32-2.53, P < .001), moderate (RR: 2.17, 95% CI: 1.65-2.85, P < .001), and severe SDB (RR: 2.66, 95% CI: 1.96-3.62, P < .001). The association was consistent in studies that adjusted for age and sex (RR: 2.17, 95% CI: 1.50-3.13, P < .001), and in studies with additional adjustment for comorbidities (RR: 1.78, 95% CI: 1.42-2.25, P < .001).

CONCLUSION

SDB is associated with RVO in adults.

Intravitreal Triamcinolone Acetonide for Diabetic Macular Edema and Macular Edema Secondary to Retinal Vein Occlusion: A Meta-Analysis

BACKGROUND

The comparative safety and efficacy of different doses of intravitreal triamcinolone acetonide (IVTA) for diabetic macular edema (DME) and macular edema (ME) secondary to retinal vein occlusion (RVO) is unclear.

OBJECTIVES

This meta-analysis aimed to compare the safety and efficacy of different doses of IVTA in this setting.

METHODS

A systematic literature search for randomized clinical trials (RCTs) was conducted on Cochrane Library, Ovid MEDLINE, and EMBASE from January 2005 to May 2022. Studies that reported on patients with DME or ME secondary to RVO that received treatment with different doses of IVTA were included. A random-effects meta-analysis was performed. Cochrane's Risk of Bias Tool 2 was used to assess the risk of bias, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) guidelines were used to assess certainty of evidence.

RESULTS

Five RCTs reporting on 1,041 eyes at baseline were included in this meta-analysis. In eyes with ME secondary to RVO, high-dose (4 mg) IVTA achieved a significantly better change in best-corrected visual acuity (WMD = -4.75 ETDRS letters, 95% CI = [-7.73, -1.78], p = 0.002) and reduction in retinal thickness (WMD = -93.02 μm, 95% CI = [-153.23, -32.82], p = 0.002) at months 4-6 compared to low-dose (1-2 mg) IVTA. However, high-dose IVTA had a higher risk of intraocular pressure-related adverse events (RR = 2.99, 95% CI = [1.05, 8.50], p = 0.04) and cataract surgery (RR = 5.67, 95% CI = [3.09, 10.41], p < 0.00001) than low-dose IVTA in eyes with ME secondary to RVO. These efficacy and safety differences in high-dose and low-dose IVTA were not observed in DME eyes.

CONCLUSIONS

The RCT evidence in this setting is limited. High-dose IVTA achieved greater improvements in visual acuity and reductions in retinal thickness than low-dose IVTA at months 4-6. However, high-dose IVTA had a less favorable safety profile than low-dose IVTA. The significance of these outcomes was based on patients with ME secondary to RVO, but not DME.

Intravitreal Anti-Vascular Endothelial Growth Factor Therapies for Retinal Disorders

Vascular endothelial growth factors (VEGFs) are key mediator of retinal and choroidal neovascularization as well as retinal vascular leakage leading to macular edema. As such, VEGF plays an important role in mediating visually significant complications associated with common retinal disorders such as diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. Various drugs that inhibit vascular endothelial growth factors (anti-VEGF therapies) have been developed to minimize vision loss associated with these disorders. These drugs are injected into the vitreous cavity in a clinic setting at regular intervals. This article provides an overview of the various anti-VEGF drugs used in ophthalmology and the common retinal conditions that benefit from this therapy.

Increased intraocular inflammation in retinal vein occlusion is independent of circulating immune mediators and is involved in retinal oedema

We aim to understand the link between systemic and intraocular levels of inflammatory mediators in treatment-naïve retinal vein occlusion (RVO) patients, and the relationship between inflammatory mediators and retinal pathologies. Twenty inflammatory mediators were measured in this study, including IL-17E, Flt-3 L, IL-3, IL-8, IL-33, MIP-3β, MIP-1α, GRO β, PD-L1, CD40L, IFN-β, G-CSF, Granzyme B, TRAIL, EGF, PDGF-AA, PDGF-AB/BB, TGF-α, VEGF, and FGFβ. RVO patients had significantly higher levels of Flt-3 L, IL-8, MIP-3β, GROβ, and VEGF, but lower levels of EGF in the aqueous humor than cataract controls. The levels of Flt-3 L, IL-3, IL-33, MIP-1α, PD-L1, CD40 L, G-CSF, TRAIL, PDGF-AB/BB, TGF-α, and VEGF were significantly higher in CRVO than in BRVO. KEGG pathway enrichment revealed that these mediators affected the PI3K-Akt, Ras, MAPK, and Jak/STAT signaling pathways. Protein-Protein Interaction (PPI) analysis showed that VEGF is the upstream cytokine that influences IL-8, G-CSF, and IL-33 in RVO. In the plasma, the level of GROβ was lower in RVO than in controls and no alterations were observed in other mediators. Retinal thickness [including central retinal thickness (CRT) and inner limiting membrane to inner plexiform layer (ILM-IPL)] positively correlated with the intraocular levels of Flt-3 L, IL-33, GROβ, PD-L1, G-CSF, and TGF-α. The size of the foveal avascular zone positively correlated with systemic factors, including the plasma levels of IL-17E, IL-33, INF-β, GROβ, Granzyme B, and FGFβ and circulating high/low-density lipids and total cholesterols. Our results suggest that intraocular inflammation in RVO is driven primarily by local factors but not circulating immune mediators. Intraocular inflammation may promote macular oedema through the PI3K-Akt, Ras, MAPK, and Jak/STAT signaling pathways in RVO. Systemic factors, including cytokines and lipid levels may be involved in retinal microvascular remodeling.

Characteristics of Hematologic Parameters in Young Patients with Retinal Vein Occlusion

INTRODUCTION

The aim of this study was to investigate the characteristics of hematologic parameters in young patients with retinal vein occlusion (RVO).

METHODS

All participants underwent routine ocular examinations and blood sample tests. Hematologic parameters obtained from a complete blood count, as well as the calculation of specific inflammatory indices, were compared between young patients with RVO and the control subjects. Correlations between hematologic inflammatory biomarkers and aqueous humor inflammatory cytokines were also investigated.

RESULTS

A total of 64 patients with RVO and 64 age- and gender-matched control subjects were included in this study. The white blood cell count, neutrophil cell count, mean platelet volume (MPV), neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), and systemic inflammatory response index (SIRI) in young patients with RVO were significantly higher than in the controls (all p < 0.05). Compared to patients with nonischemic RVO, patients with ischemic RVO had higher NLR, SII, and SIRI values (p = 0.032, p = 0.035, and p = 0.039, respectively). The areas under the receiver operator characteristic curve were 0.725, 0.651, 0.649, and 0.634 for the MPV, NLR, SII, and SIRI, respectively. In addition, a higher NLR was related to higher levels of interleukin 6 (IL-6; p = 0.046, R = 0.463), and a higher SII was related to higher levels of IL-6 (p = 0.034, R = 0.488) and vascular endothelial growth factor (p = 0.020, R = 0.528).

CONCLUSION

The NLR, SII, and SIRI were significantly elevated in young patients with RVO, especially in young patients with ischemic RVO. NLR and SII were positively correlated with IL-6 levels in aqueous humor, which indicated that systemic inflammation plays an important role in the onset of RVO in young patients.

Novel pharmaceuticals for the management of retinal vein occlusion and linked disorders

INTRODUCTION

Retinal vein occlusion (RVO) is the second leading cause of blindness from retinal vascular disease behind diabetic retinopathy. Anti-vascular endothelial growth factor (VEGF) and glucocorticoid therapy are the cornerstones of pharmaceutical treatment for RVO. There is considerable interest in developing new pharmaceuticals in and out of these two classes to reduce costs, lower injection burden, and treat the occlusion itself, rather than the complications.

AREAS COVERED

In this review, we discuss novel pharmaceuticals for the treatment of RVO outside of current standard of care. We performed a comprehensive literature search encompassing pharmaceuticals that have recently been approved or have shown promising results in early clinical trials or animal models.

EXPERT OPINION

Anti-VEGF therapy remains the most efficacious treatment for RVO with a very favorable side effect profile. New biosimilars reduce costs while maintaining efficacy. Novel glucocorticoids may be a useful therapy in patients for whom anti-VEGF therapy has failed, or as an adjunct. Pharmaceuticals in other drug classes, particularly those with neuroprotective or regenerative properties, as well as those geared toward treating the occlusion itself, represent exciting options for early RVO therapy, but are likely years away from clinical relevance.

Effects of Intravitreal Ranibizumab Injection to Treat Macular Edema due to Central Retinal Vein Occlusion on Choroidal Findings and Functional-Morphological Parameters

INTRODUCTION

Little research has examined the effects of anti-vascular endothelial growth factor therapy on subfoveal choroidal thickness (SCT), choroidal blood flow, aqueous flare, and humor levels of growth and inflammatory factors in patients with macular edema due to central retinal vein occlusion (CRVO).

METHODS

In 58 patients with macular edema due to CRVO treated by intravitreal ranibizumab injection (IRI), we retrospectively assessed best-corrected visual acuity (BCVA, assessed as the logarithm of the minimum angle of resolution [logMAR]), 8 aqueous factors (by suspension array), mean blur rate (MBR; estimated by laser speckle flowgraphy as a measure of choroidal blood flow), aqueous flare (with a laser flare meter), and SCT and central macular thickness (CMT; by optical coherence tomography).

RESULTS

After 4 weeks, IRI resulted in a significant improvement in BCVA and CMT and a significant reduction in SCT, choroidal MBR, and aqueous flare. SCT was significantly positively correlated with placental growth factor and significantly negatively correlated with platelet-derived growth factor-AA, and change in SCT was significantly negatively correlated with change in BCVA (logMAR). Aqueous flare was significantly negatively correlated with SCT.

CONCLUSION

Growth and inflammatory factors may be associated with SCT, and changes in SCT may be associated with changes in BCVA after IRI to treat macular edema due to CRVO.

The Impact of Intraocular Treatment on Visual Acuity of Patients Diagnosed with Branch Retinal Vein Occlusions

Branch retinal vein occlusions are a significant cause of vision loss and present several ophthalmic and systemic risk factors, including age, hypertension, hyperlipidemia and glaucoma. Retinal vein occlusion is the second-most-common retinal vascular disease. This study evaluated the effects of Ozurdex in contrast to a combination therapy with anti-vascular endothelial growth factor (VEGF) and cortisone in treatment-naive branch retinal vein occlusions-macular edema (BRVO-ME) cases, at 4-month and 6-month follow-ups. Thirty eyes were included in the study, which were divided into two groups. The first group consisted of 15 eyes, and each received 1 injection of dexamethasone intravitreal implant Ozurdex (DEX). The second group of 15 eyes received 3 intravitreal injections, the first and second with the anti-vascular endothelial growth factor aflibercept and the third one with 4 mg of triamcinolone acetonide (Vitreal S), spaced at one month. The best corrected visual acuity (BCVA) results suggested that the peak efficacy was at 4 months for both groups, with mean values of 0.5 LogMAR and 0.4 LogMAR. Regarding macular edema, there were no significant changes between the 4- and 6-month follow-up periods, with mean values of 361 μm and 390 μm. Six patients experienced transient raised intraocular pressure at one week after treatment. This study highlights the benefits to visual acuity of the combination of anti-vascular endothelial growth factor and cortisone, which represents a viable solution with similar results to Ozurdex therapy.

The relation between serum inflammatory marker levels and serous retinal detachment in macular edema secondary to retinal vein occlusion Serum inflammatory marker levels in serous retinal detachment secondary to retinal vein occlusion

PURPOSE

To assess blood-derived inflammatory markers in macular edema (ME) secondary to retinal vein occlusion (RVO) with and without serous retinal detachment (SRD).

MATERIALS-METHODS

Treatment-naive patients with ME secondary to RVO were divided into two groups according to the existence of SRD in optical coherence tomography (OCT) images; group 1 consisted of 60 patients with SRD, and group 2 consisted of 60 patients without SRD. Age and gender-matched 60 patients formed group 3 as healthy controls. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic inflammation index (SII) were calculated from blood samples to assess the differences in the levels of blood-derived inflammatory markers and the presence of SRD.

RESULTS

The PLR, NLR, and SII values were higher in groups 1 and 2 than in group 3 (p<0.05, each comparison). The NLR and SII values were also significantly elevated in group 1 compared to group 2 (p = 0.000 and p = 0.000, respectively). The optimal cutoff value to estimate SRD in patients with ME secondary to RVO for NLR was 2.08 with 66.7% sensitivity and 65% specificity; for SII was 530.93 with 68.3% sensitivity and specificity.

CONCLUSION

SII is a reliable and cost-effective tool for predicting SRD, an inflammatory OCT biomarker in ME secondary to RVO.

Systemic Inflammatory Marker Levels in Serous Macular Detachment Secondary to Retinal Vein Occlusion

Purpose

To evaluate the association of systemic inflammatory marker levels in macular edema with serous macular detachment (SMD) secondary to retinal vein occlusion (RVO).

Methods

Patients diagnosed with RVO were categorized into two groups based on the presence or absence of SMD: Group 1 included 30 eyes with SMD, while Group 2 included 30 eyes without SMD. Levels of neutrophils, monocytes, lymphocytes, thrombocytes, and mean platelet volume (MPV) were analyzed. Systemic inflammatory markers, including neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII), were calculated and compared between the two groups.

Results

The mean neutrophil levels were significantly higher in Group 1 (P = 0.002). The mean lymphocyte, monocytes, thrombocyte, and MPV levels did not differ significantly between groups. NLR and SII levels were significantly higher in the SMD group (P = 0.004 and P = 0.016, respectively). There was no significant difference between the groups in terms of PLR. The optimal receiver operator characteristic (ROC) cut-off value of NLR for SMD was calculated as 1.55 with 73% sensitivity and 63% specificity (area under the curve [AUC] = 0.714, 95% confidence interval [CI]: 0.584-0.845). The optimal ROC cut-off value of SII for SMD was calculated as 451.75 with 63% sensitivity and 63% specificity (AUC = 0.681, 95% CI: 0.546-0.816). In this study, branch RVO was present in 48 patients, and central RVO was present in 12 patients. Neutrophil, MPV levels, and NLR, PLR, SII ratios were similar between patients with branch and central occlusion.

Conclusion

Neutrophil levels, NLR, and SII were found to be significantly higher in eyes with SMD secondary to RVO.

Correlation Between Imaging Morphological Findings and Laboratory Biomarkers in Patients with Retinal Vein Occlusion

INTRODUCTION

The aim of this study was to investigate the possible correlation between peripheral blood biomarkers and morphological characteristics of retinal imaging in patients with retinal vein occlusion (RVO).

METHODS

Participants in this cross-sectional observational study were 65 consecutive patients (65 eyes) with treatment-naïve RVO, who underwent spectral-domain optical coherence tomography (SD-OCT) and fundus fluorescein angiography (FFA). In addition, peripheral blood samples were taken to evaluate full blood count and biochemical parameters. The association between imaging characteristics and laboratory parameters was examined.

RESULTS

Eyes with subretinal fluid presented significantly higher neutrophil-to-lymphocyte ratios (p = 0.028). Hyperreflective foci on SD-OCT were found to be associated with higher triglyceride levels (p = 0.024). The presence of cysts on SD-OCT was associated with significantly higher triglycerides (p = 0.010). Central subfield thickness (CST) higher than 464 μm was associated with higher lymphocyte count (p = 0.016) and higher urea (p = 0.015). No significant associations were found between laboratory parameters and intraretinal fluid, ellipsoid zone and external limiting membrane condition, or epiretinal membrane and macular ischemia.

CONCLUSIONS

Specific imaging morphological characteristics were found to be associated with laboratory parameters in patients with RVO. These findings may help reveal the pathophysiology of RVO and its correlation with the development of specific clinical signs, while they could guide individualized treatment.

Interleukin-6 and Macular Edema: A Review of Outcomes with Inhibition

This paper describes the current literature on the molecular pathophysiology of interleukin-6 (IL-6) in the genesis of macular edema and on the outcomes with IL-6 inhibitors in the treatment of non-infectious macular edema. The role of IL-6 in the development of macular edema has been well elucidated. IL-6 is produced by multiple cells of the innate immune system and leads to a higher likelihood of developing autoimmune inflammatory diseases, such as non-infectious uveitis, through a variety of mechanisms. These include increasing the helper T-cell population over the regulatory T-cell population and leading to the increased expression of inflammatory cytokines, such as tumor necrosis factor-alpha. In addition to being key in the generation of uveitis and subsequent macular edema through these inflammatory pathways, IL-6 also can lead to the development of macular edema through other pathways. IL-6 induces the production of vascular endothelial growth factor (VEGF) and facilitates vascular leakage by downregulating tight junction proteins in retinal endothelial cells. Clinically, the use of IL-6 inhibitors has been found to be efficacious primarily in the context of treatment-resistant non-infectious uveitis and secondary macular edema. IL-6 is a key cytokine in retinal inflammation and macular edema. It is thus not surprising that the use of IL-6 inhibitors in treatment-resistant macular edema in the setting of non-infectious uveitis has been well documented as an effective treatment option. The use of IL-6 inhibitors in macular edema secondary to non-uveitic processes has only begun to be explored.

Laser-Induced Porcine Model of Experimental Retinal Vein Occlusion: An Optimized Reproducible Approach

Retinal vein occlusion (RVO) is a frequent visually disabling condition. The management of RVO continues to challenge clinicians. Macular edema secondary to RVO is often recurrent, and patients typically require intravitreal injections for several years. Understanding molecular mechanisms in RVO is a key element in improving the treatment of the condition. Studying the molecular mechanisms in RVO at the retinal level is possible using animal models of experimental RVO. Most studies of experimental RVO have been sporadic, using only a few animals per experiment. Here, we report on 10 years of experience of the use of argon laser-induced experimental RVO in 108 porcine eyes from 65 animals, including 65 eyes with experimental branch retinal vein occlusion (BRVO) and 43 eyes with experimental central retinal vein occlusion (CRVO). Reproducibility and methods for evaluating and controlling ischemia in experimental RVO are reviewed. Methods for studying protein changes in RVO are discussed in detail, including proteomic analysis, Western blotting, and immunohistochemistry. Experimental RVO has brought significant insights into molecular changes in RVO. Testing intravitreal interventions in experimental RVO may be a significant step in developing personalized therapeutic approaches for patients with RVO.

Assessment of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in patients with high myopia

BACKGROUND

Previous reports have suggested that inflammation levels play a crucial role in the pathogenesis of high myopia (HM). This study aimed to investigate the relationship between HM and systemic inflammation using the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR).

METHODS

Overall, 100 age- and sex-matched participants were recruited for the study, including 50 participants each in the non-HM (NHM) and HM groups. Ocular examinations and blood tests were performed. The NLR and PLR values were calculated from complete blood counts. Receiver operating characteristic (ROC) curves and optimal cut-off values were used to determine the optimal values of the NLR and PLR to distinguish between the HM and NHM groups.

RESULTS

The values of NLR and PLR were significantly elevated in the HM group compared with those in the NHM group (P < 0.001 and P = 0.010, respectively). Axial length (AL) was significantly correlated with the NLR (r = 0.367, P < 0.001) and PLR (r = 0.262, P = 0.009). In the ROC analysis, the NLR value to distinguish between the HM and NHM groups was 0.728; the best cut-off value was 2.68, with 76% sensitivity and 62% specificity. The PLR value to distinguish between the HM and NHM groups was 0.650; the best cut-off value was 139.69, with 52% sensitivity and 76% specificity.

CONCLUSION

The findings of this study indicate that the development of HM may be associated with systemic inflammation measured using the NLR and PLR.

TRIAL REGISTRATION

The study was registered on December 28, 2021 ( http://www.chictr.org.cn ; ChiCTR2100054834).

Risk Factors and Treatment Strategy for Retinal Vascular Occlusive Diseases

Retinal occlusive diseases are common diseases that can lead to visual impairment. Retinal artery occlusion and retinal vein occlusion are included in the clinical entity, but they have quite different pathophysiologies. Retinal artery occlusion is an emergent eye disorder. Retinal artery occlusion is mainly caused by thromboembolism, which frequently occurs in conjunction with life-threatening stroke and cardiovascular diseases. Therefore, prompt examinations and interventions for systemic vascular diseases are often necessary for these patients. Retinal vein occlusion is characterized by retinal hemorrhage and ischemia, which may impair visual function via several complications such as macular edema, macular ischemia, vitreous hemorrhage, and neovascular glaucoma. Even though anti-vascular endothelial growth factor therapy is the current established first-line of treatment for retinal vein occlusion, several clinical studies have been performed to identify better treatment protocols and new therapeutic options. In this review, we summarize the current findings and advances in knowledge regarding retinal occlusive diseases, particularly focusing on recent studies, in order to provide an update for a better understanding of its pathogenesis.

Elevated Neutrophil Counts, Triglycerides, Monocyte/High-Density Lipoprotein Ratios, and Lower High-Density Lipoprotein in Patients with Retinal Vein Occlusion

INTRODUCTION

The aim of the study was to evaluate associations of peripheral blood immune cells and blood lipid profile levels with retinal vein occlusion (RVO).

METHODS

This retrospective study included 127 patients with RVO and 108 controls. Patients with RVO were divided into branch RVO (BRVO), central RVO (CRVO), ischemic RVO, or nonischemic RVO groups. Medical records were collected and analyzed.

RESULTS

The RVO group had higher mean neutrophil, triglyceride (TG), and monocyte/high-density lipoprotein (HDL) ratio (MHR) levels and lower HDL levels (p = 0.037, p < 0.001, p = 0.004, and p = 0.002, respectively). TG and MHR levels were significantly higher in the BRVO and CRVO groups compared with the control group (p < 0.001 and p = 0.016, respectively), but there was no difference in BRVO and CRVO group (p = 0.972 and p = 0.916, respectively). Mean HDL levels were significantly lower in the BRVO and CRVO groups than in the control group (p = 0.005), but the difference between the BRVO group and CRVO group was not significant (p = 0.290). Neutrophils, TG, and MHR were independent risk factors for RVO. HDL was an independent protective factor for RVO. Age was an independent risk factor for ischemic RVO.

CONCLUSIONS

Lower HDL, and higher neutrophil, TG, and MHR levels are associated with RVO. Age is an independent risk factor for ischemic RVO.

Effects of Lycopene Attenuating Injuries in Ischemia and Reperfusion

Tissue and organ ischemia can lead to cell trauma, tissue necrosis, irreversible damage, and death. While intended to reverse ischemia, reperfusion can further aggravate an ischemic injury (ischemia-reperfusion injury, I/R injury) through a range of pathologic processes. An I/R injury to one organ can also harm other organs, leading to systemic multiorgan failure. A type of carotenoid, lycopene, has been shown to treat and prevent many diseases (e.g., rheumatoid arthritis, cancer, diabetes, osteoporosis, male infertility, neurodegenerative diseases, and cardiovascular disease), making it a hot research topic in health care. Some recent researches have suggested that lycopene can evidently ameliorate ischemic and I/R injuries to many organs, but few clinical studies are available. Therefore, it is essential to review the effects of lycopene on ischemic and I/R injuries to different organs, which may help further research into its potential clinical applications.

Analysis of the Cytokine Expression in the Aqueous Humor of Individuals with BRVO-Associated Macular Edema

Purpose

This study aimed to determine the expression levels of vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in the aqueous humor of patients with macular edema (ME) caused by branch retinal vein occlusion (BRVO), as well as to investigate the relationship between the cytokines as mentioned earlier and best-corrected visual acuity (BCVA), ME, and the degree of ME from the molecular level.

Methods

In a prospective observational study, fluorescein fundus angiography (FFA) and optical coherence tomography (OCT) were used to classify 58 patients with non-ischemic BRVO-ME into three groups according to the degree of ME: 14-mild, 17-moderate, and 27-severe. The specific concentration of IL-6, VEGF, ICAM-1, and VCAM-1 in the aqueous humor was detected using the BD CSCanto™ II Flow Cytometer (US). Spearman or Pearson correlation analysis was used to test the correlation between the levels of BCVA and severity of ME and the expression levels of IL-6, VEGF, ICAM-1, and VCAM-1 in the aqueous humor.

Results

According to the obtained data, BCVA did not correlate with the severity of ME, and these four cytokines expression levels in patients' aqueous humor (P > 0.05). Moreover, BCVA did not correlate with mild, moderate, or severe ME as well (P > 0.05). However, the levels of these four cytokines were correlated with the severity of the ME. These underlined cytokines were linked to the mild, moderate, and severe degrees of ME. VEGF was also significantly correlated (r > 0.8, P < 0.0001) with the severity of ME.

Conclusions

This study suggests that the severity of ME in BRVO-ME patients is significantly correlated with the expression levels of IL-6, VEGF, ICAM-1, and VCAM-1 in the aqueous humor. Lowering the level of disease-associated cytokines may potentially reduce the degree of ME. Therefore, an in-depth study of the levels and the relationship may provide some evidence for the pathogenesis, treatment, and prevention of BRVO-ME.

Deletion of the Pedf gene leads to inflammation, photoreceptor loss and vascular disturbances in the retina

Retinal diseases are often accompanied by inflammation, vascular abnormalities, and neurodegeneration that decrease vision. Treatment with exogenous PEDF is widely shown to alleviate these conditions leading us to hypothesize that loss of function of the PEDF gene disrupts these pathways and leads to visual loss. Measurements were carried out by detailed phenotyping of PEDF null mice to assess expression of immunomodulators, glia activation, systemic inflammation, vascular disturbances, and visual sensitivity often associated with retinal pathologies. With a deletion of the Pedf gene, there was increased expression of several immune modulators in Pedf^-/- retinas and serum with IL-2 and GM-CSF upregulated in both. Increases in retina glia activation and macrophage infiltration, levels of serum c-reactive protein (CRP), numbers of white and red blood cells and platelets and decreased blood glucose levels were all features associated with PEDF null mice. With PEDF gene deletion, there was also a notable increase in apoptosis in early developing retinas (PN3), reduced thickness of the photoreceptor layer, swelling of the inner plexiform layer, reduced retinal sensitivity and steady-state reduced activation of Erk and Akt, two signaling pathways used by PEDF. There is a substantial body of animal data emphasizing utility of PEDF treatment in homeostatic regulation of retinal diseases, including diabetic retinopathy and age-related macular degeneration but there is little agreement or evidence on the role of endogenous PEDF in retinal diseases. Our findings strongly support the concept that a deletion of the PEDF gene makes the retina vulnerable to diseases, and argue that endogenous PEDF plays a critical role in limiting pathological events in the retina.

Long-term outcomes for patients treated for macular oedema secondary to retinal vein occlusion: a systematic review

This systematic review assessed the long-term outcomes for patients treated with intravitreal antivascular endothelial growth factor or dexamethasone for macular oedema (MO) secondary to retinal vein occlusion (RVO). Studies investigating patients of all ages with MO due to RVO only were included. The review was deliberately broad in scope, including comparative and non-comparative studies to ensure inclusion of real-world type evidence. Risk of bias was assessed. In total, 76 data sets were included (10 775 participants). Overall, mean best-corrected visual acuity (BCVA) improved from baseline to 5 years by 16.1 letters (p<0.01). BCVA improved from baseline in both central RVO (CRVO) and branch RVO (BRVOs) at 2 years, by 9.1 (p<0.01) (difference from baseline in CRVOs) and 9.1 (p<0.01) letters, respectively. At 5 years, BCVA improved from baseline in CRVOs by 15.6 letters and in BRVOs by 16.2; the difference between RVO types was not significant (p=0.18). Two studies had 5-year data for ranibizumab, and improvement was evident. There was no significant difference between outcomes in randomised controlled trials (RCTs) compared with non RCTs. These results suggest a benefit to receiving long-term intravitreal treatments for MO due to RVO.

Clinical Features of Central Retinal Vein Occlusion in Young Patients

Retinal vein occlusion (RVO) is the second most common retinal vascular disease. Central RVO (CRVO), in which obstruction occurs posterior to the lamina cribrosa due to various causes, manifests with extensive venous tortuosity, dilatation of blood vessels in the four quadrants, and retinal hemorrhage. The presence of macular edema decreases visual acuity in patients with CRVO, especially in elderly patients with hypertension, hyperlipidemia, and diabetes. In the last decade, treatment modalities for CRVO have improved, with anti-vascular endothelial growth factor agents being widely used as treatment. However, there are cases of refractory or recurrent macular edema. Moreover, CRVO also occurs in young patients. This article reviews previous studies and case reports and summarizes the differences in etiological factors, clinical manifestations, treatment, and prognosis between young and elderly patients. Due to the low incidence of CRVO in young patients, clinical data from these age groups are limited. Hence, further studies are warranted to explore the differences between age groups to improve individualization of treatment of young patients.

Comparison of each retinal layer thicknesses between eyes with CRVO and normal contralateral eyes

Purpose

To evaluate the difference in each retinal layer thickness in central retinal vein occlusion (CRVO) with resolved macular edema after intravitreal antivascular endothelial growth factor injection and normal contralateral eyes..

Methods

Patients with ischemic and nonischemic CRVO whose macular edema resolved after intravitreal antivascular endothelial growth factor injections and did not recur for at least 6 months, and a normal contralateral eye were enrolled. Each retinal layer thickness between CRVO and normal contralateral eyes was compared according to Early Treatment Diabetic Retinopathy Study subfields using spectral domain optical coherence tomography.

Results

The thicknesses of outer nuclear layer, photoreceptor layer, and retinal pigment epithelium in central ring, ganglion cell layer, inner plexiform layer, outer nuclear layer, and photoreceptor layer in the inner ring, and ganglion cell layer in the outer ring of CRVO eyes were significantly thinner than those of normal contralateral eyes (all p < 0.05). Whereas, inner nuclear layer and outer plexiform layer thicknesses in central ring of CRVO eyes were 23.86 ± 8.8 and 25.76 ± 7.6 μm, respectively, which was significantly thicker than those of normal contralateral eyes (19.52 ± 7.7 and 22.76 ± 6.5 μm; p = 0.019 and p = 0.043, respectively). Additionally, the mean best-corrected visual acuity of CRVO eyes were significantly correlated with photoreceptor layer thickness in central ring (p = 0.005).

Conclusions

In CRVO eyes with resolved macular edema, the outer retinal layers were thinner as well as inner retinal layers, whereas inner plexiform layer and outer nuclear layer were thicker than normal fellow eyes. Additionally, photoreceptor layer thickness in foveal area had a significant impact on visual acuity in CRVO.

Characterization of Macrophage-Like Cells in Retinal Vein Occlusion Using En Face Optical Coherence Tomography

Purpose

To investigate the clinical features of a macrophage-like cell (MLC) obtained by en face optical coherence tomography (OCT) in retinal vein occlusion (RVO).

Methods

The study involved 36 patients with treatment-naïve unilateral acute RVO, including 21 branch RVO (BRVO) and 15 central RVO. Vessel density and macular thickness were quantified using OCT angiography. A 3-μm en face OCT slab on the inner limiting membrane in the optic nerve head (ONH) region or macular region was used to visualize the MLCs. The MLCs were binarized and quantified using a semiautomated method. The unaffected fellow eyes served as the control group.

Results

The morphology of MLCs appeared larger and plumper in RVO eyes. The mean MLC density in the ONH and macular regions was 2.46 times and 2.86 times higher than their fellow eyes, respectively (p < 0.001). The macular MLC density of the occlusive region was significantly lower than that of the unaffected region in BRVO (p = 0.01). The ONH and macular MLC densities in the non-perfused region were significantly lower than those in the perfused region in all RVO eyes (p < 0.001). The ONH MLC density in RVO eyes was negatively correlated with radial peripapillary capillary vessel density (r = -0.413, p = 0.012). Both ONH and macular MLC densities were positively correlated with macular thickness (r = 0.505, p = 0.002; r = 0.385, p = 0.02, respectively).

Conclusion

The increased density and changes of morphology characterized by OCT may indicate generalized activation and aggregation of MLCs in RVO. More MLCs are recruited in the perfused region rather than the non-perfused region. RVO eyes with a higher density of MLCs tend to suffer from the thicker macula.

Complete Blood Count-Derived Inflammation Indices and Retinal Vein Occlusion: A Case-Control Study

Introduction

This study evaluated complete blood count-derived inflammation indices in patients with retinal vein occlusion (RVO).

Methods

Participants in this case–control study were 54 patients with RVO and 54 age- and sex-matched control subjects. All participants underwent a thorough ophthalmic examination, as well as blood sample testing for complete blood count. Comparison of all parameters derived from complete blood count as well as calculation of specific indices was performed between patients with RVO and controls.

Results

Patients with RVO presented significantly higher white blood cell count (p = 0.033), neutrophil count (p = 0.003), neutrophil-to-lymphocyte ratio (NLR, p = 0.002), red cell distribution width (RDW, p = 0.009), mean platelet volume (MPV, p = 0.023), and systemic immune-inflammatory index (SII, p = 0.007) compared to controls. Receiver operator characteristic curve (ROC) analysis showed that NLR was superior to other inflammatory indices, having the greatest area under the curve. The optimal cutoff value for NLR to predict RVO was 2.29 with 46.2% sensitivity and 77.8% specificity.

Conclusion

Patients with RVO presented increased NLR, RDW, MPV, and SII, providing evidence that inflammation plays an important role in the pathogenesis of RVO. Complete blood cell count-derived indices can be easily calculated and may serve as an easy, simple, and cost-effective tool to evaluate the degree of systemic inflammation in patients with RVO, so as to potentially guide treatment.

A Review of Intraocular Biomolecules in Retinal Vein Occlusion: Toward Potential Biomarkers for Companion Diagnostics

Retinal vein occlusion (RVO) is one of the most common retinal vascular diseases. The pathogenesis of RVO is multifactorial and involves a complex interplay among a variety of vascular and inflammatory mediators. Many cytokines, chemokines, growth factors, and cell adhesion molecules have been reported to be implicated. Treatments for RVO are directed at the management of underlying risk factors and vision-threatening complications, including macula edema (ME) and neovascularization. Intravitreal anti-VEGF agents are currently considered as the first-line treatment for ME secondary to RVO (RVO-ME), but a substantial proportion of patients responded insufficiently to anti-VEGF agents. Since RVO-ME refractory to anti-VEGF agents generally responds to corticosteroids and its visual outcome is negatively correlated to disease duration, prediction of treatment response at baseline in RVO-ME may significantly improve both cost-effectiveness and visual prognosis. Several bioactive molecules in the aqueous humor were found to be associated with disease status in RVO. This review aims to present a comprehensive review of intraocular biomolecules reported in RVO, including VEGF, IL-6, IL-8, MCP-1, sICAM-1, IL-12, IL-13, sVEGFR-1, sVEGFR-2, PDGF-AA, etc., highlighting their association with disease severity and/or phenotype, and their potential roles in prognostic prediction and treatment selection. Some of these molecules may serve as biomarkers for aqueous humor-based companion diagnostics for the treatment of RVO in the future.

Two-Week Central Macular Thickness Reduction Rate >37% Predicts the Long-Term Efficacy of Anti-vascular Endothelial Growth Factor Treatment for Macular Edema Secondary to Retinal Vein Occlusion

Objective

To determine if the early response assessments can predict the long-term efficacy of anti-vascular endothelial growth factor (VEGF) treatment for macular edema secondary to retinal vein occlusion (RVO-ME).

Methods

A retrospective study of patients with diagnosis of RVO-ME and intravitreal anti-VEGF treatment was conducted. Clinical characteristics including age, gender, disease subtype and disease duration were recorded at baseline. The best corrected visual acuity (BCVA and logMAR), intraocular pressure (IOP), and central macular thickness (CMT) were recorded at baseline, 2 weeks, and every month (months 1–6) after injection. Further, we compared the early response assessments between the cured group (6-month CMT ≤ 250 μm) and the uncured group (6-month CMT &gt; 250 μm).

Results

A total of 164 eyes in 164 patients (77 male and 87 female) were included. At each post-injection time point, both BCVA and CMT are significantly decreased from baseline (all P &lt; 0.001). Spearman’s test showed that 2-week CMT reduction rate after the first injection was negatively correlated with BCVA at 6 months (r = −0.359, P &lt; 0.001). Compared with the uncured group (47 cases), the cured group (117 cases) was younger (59.53 ± 11.68 vs. 65.19 ± 13.10 years old, P &lt; 0.01), had more BRVO patients (76.1% vs. 44.7%, P &lt; 0.01), a shorter disease duration (1.92 ± 2.43 vs. 5.05 ± 4.32 months, P &lt; 0.01), lower baseline CMT (527.09 ± 154.95 vs. 768.96 ± 287.75 μm, P &lt; 0.01), and lower baseline BCVA (0.86 ± 0.44 vs. 1.31 ± 0.51, P &lt; 0.01). At each post-injection time point, the cured group had lower CMT and BCVA values when compared to the uncured group (all P &lt; 0.01), and the 2-week CMT reduction rate was identified as the earliest response time to predict the long-term treatment efficacy. Moreover, ROC curve analysis indicated that a 2-week CMT reduction rate &gt;37% yielded the best cut-off point for predicting the long-term cure of anti-VEGF treatment at 6 months (P &lt; 0.001). Multivariable logistic regression confirmed that the 2-week CMT reduction rate &gt;37% was independently associated with the 6-month cured rate (OR = 9.639, 95% Cl = 1.030–90.227, P = 0.047).

Conclusion

Age, disease duration, baseline CMT, and baseline BCVA are associated with visual outcomes at 6-month of anti-VEGF treatment for RVO-ME. The “2-week CMT reduction rate &gt;37%” after the first injection is an independent factor to predict better long-term outcomes.

Effect of Alternate Treatment with Intravitreal Corticosteroid and Anti-VEGF for Macular Edema Secondary to Retinal Vein Occlusion

Purpose

To evaluate whether treatment with intravitreal corticosteroid and anti-vascular endothelial growth factor (VEGF) injections alternately can improve treatment outcomes of macular edema (ME) caused by retinal vein occlusion (RVO).

Methods

This dual-center retrospective study included 112 eyes with treatment-naïve ME secondary to RVO that were alternately treated with intravitreal corticosteroid and anti-VEGF injections (33 eyes, alternate group) or treated only with intravitreal anti-VEGF injections (79 eyes, anti-VEGF group) on a pro re nata basis.

Results

During the 12-month follow-up period, the alternate group achieved a visual acuity gain of 0.39 logMAR, while the anti-VEGF group achieved a gain of 0.21 logMAR (P=0.042). The alternate group demonstrated a reduction in the central macular thickness of 229.9-μm, while the anti-VEGF group achieved a reduction of 220.1 μm (P=0.887). The alternate group required an average of 5.2 injections, while the anti-VEGF received 4.2 injections (P < 0.001). In a propensity score-matched cohort to compensate for the differences in the injection numbers between the two groups, the alternate group achieved a better visual acuity gain than the anti-VEGF group at month 12 (0.39 logMAR vs. 0.17 logMAR, P=0.048).

Conclusions

In ME secondary to RVO, treatment with intravitreal corticosteroid and anti-VEGF injections alternately resulted in a more favorable visual outcome compared with intravitreal anti-VEGF monotherapy.

Retinal Blood Flow as a Predictor of Recurrence of Macular Edema after Intravitreal Ranibizumab Injection in Central Retinal Vein Occlusion

INTRODUCTION

To investigate the relationship between retinal blood flow and the presence or absence of macular edema (ME) recurrence after intravitreal ranibizumab injection (IRI) in patients with central retinal vein occlusion (CRVO).

METHODS

We reviewed the medical records of 16 eyes with ME associated with CRVO. All eyes had received pro re nata IRI. Repeat IRI was performed if the central macular thickness was ≥300 µm. At 12 months, patients without additional IRI in the past 6 months were assigned to the resolved group, and those with additional IRI, to the recurrence group. We used laser speckle flowgraphy (LSFG) to measure the mean blur rate (MBR) of the optic disc before and after IRI.

RESULTS

Ten of the 16 eyes were assigned to the resolved group, and the other 6 eyes to the recurrence group. At several visits in the 12 months after IRI, MBR was significantly higher in the resolved group than in the recurrence group. Percent change of MBR (%Δ MBR) from baseline was significantly higher in the resolved group than in the recurrence group at 1 month (initial %Δ MBR) and 11 and 12 months. Multivariate stepwise analysis showed that the initial %Δ MBR was significantly and negatively correlated with the number of IRIs.

DISCUSSION/CONCLUSION

These findings suggest that determining %Δ MBR in LSFG may be a useful way to determine the likelihood of ME recurrence in CRVO patients.

Inflammatory resolution and vascular barrier restoration after retinal ischemia reperfusion injury

Background

Several retinal pathologies exhibit both inflammation and breakdown of the inner blood-retinal barrier (iBRB) resulting in vascular permeability, suggesting that treatments that trigger resolution of inflammation may also promote iBRB restoration.

Methods

Using the mouse retinal ischemia-reperfusion (IR) injury model, we followed the time course of neurodegeneration, inflammation, and iBRB disruption and repair to examine the relationship between resolution of inflammation and iBRB restoration and to determine if minocycline, a tetracycline derivative shown to reverse microglial activation, can hasten these processes.

Results

A 90-min ischemic insult followed by reperfusion in the retina induced cell apoptosis and inner retina thinning that progressed for approximately 2 weeks. IR increased vascular permeability within hours, which resolved between 3 and 4 weeks after injury. Increased vascular permeability coincided with alteration and loss of endothelial cell tight junction (TJ) protein content and disorganization of TJ protein complexes. Shunting of blood flow away from leaky vessels and dropout of leaky capillaries were eliminated as possible mechanisms for restoring the iBRB. Repletion of TJ protein contents occurred within 2 days after injury, long before restoration of the iBRB. In contrast, the eventual re-organization of TJ complexes at the cell border coincided with restoration of the barrier. A robust inflammatory response was evident a 1 day after IR and progressed to resolution over the 4-week time course. The inflammatory response included a rapid and transient infiltration of granulocytes and Ly6C⁺ classical inflammatory monocytes, a slow accumulation of Ly6C^neg monocyte/macrophages, and activation, proliferation, and mobilization of resident microglia. Extravasation of the majority of CD45⁺ leukocytes occurred from the superficial plexus. The presence of monocyte/macrophages and increased numbers of microglia were sustained until the iBRB was eventually restored. Intervention with minocycline to reverse microglial activation at 1 week after injury promoted early restoration of the iBRB coinciding with decreased expression of mRNAs for the microglial M1 markers TNF-α, IL-1β, and Ptgs2 (Cox-2) and increased expression of secreted serine protease inhibitor Serpina3n mRNA.

Conclusions

These results suggest that iBRB restoration occurs as TJ complexes are reorganized and that resolution of inflammation and restoration of the iBRB following retinal IR injury are functionally linked.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02237-5.

Obstructive Sleep Apnea is Related with the Risk of Retinal Vein Occlusion

BACKGROUND

Retinal vein occlusion (RVO) was a vision-threatening retinal vascular disorder, however, the relationship between obstructive sleep apnea (OSA) and RVO risk remained unclear.

METHODS

A total of 45 RVO cases and 45 controls between April 2018 and April 2020 were included. All the participants underwent full-night polysomnography (PSG) and thus detected the severity of OSA. Besides, the relationship between the apnea-hypopnea index (AHI) and oxidative and inflammatory biomarkers, including 8-hydroxy-2 deoxyguanosine (8-OHdG), C-reactive protein (CRP), interleukin 1 beta (IL1β), interleukin 6 (IL6) and tumor necrosis factor alpha (TNFα) were detected. The incidences of macular edema (ME) and neovascular glaucoma (NVG) were detected in a three-months follow-up.

RESULTS

In this case-control study, it was found that OSA incidence was increased in the RVO cases comparing with the cataract controls. Advanced analyses about the RVO subtypes demonstrated that incidence of OSA was higher in the central RVO (CRVO) cases comparing with branch RVO (BRVO) cases. Plasma samples from OSA cases demonstrated relatively higher concentrations of oxidative stress parameters and inflammatory biomarkers, including 8-OHdG, CRP, IL1β, and IL6, in the RVO cases. Significant linear correlations between AHI and oxidative/inflammatory biomarkers were detected, and advanced analyses on the OSA subtypes demonstrated that these biomarkers were significantly higher in cases with later stages of OSA. In a three months follow-up, an impaired visual activity improvement rate and increased ME incidence in the OSA group among all the RVO cases were detected.

CONCLUSION

OSA was related with an increased incidence of RVO. Besides, OSA would lead to increased oxidative and inflammatory biomarkers concentrations in the RVO cases. OSA could be used as a harmful prognostic factor of visual activity improvement and ME incidences. These findings highlighted the role of OSA in the development of RVO.