Cytokine Kinetics after Monthly Intravitreal Bevacizumab for Retinal Vein Occlusion Associated with Macular Oedema

Predictors of treatment outcomes following treat-and-extend regimen with aflibercept for branch retinal vein occlusion: post-hoc analysis of the PLATON trial

We investigated predictors of visual outcomes and injection interval in macular edema (ME) secondary to branch retinal vein occlusion (BRVO) treated with a treat-and-extend (TAE) regimen. All 48 patients in a multicenter study were followed for 52 weeks and received three monthly intravitreal aflibercept injections before the TAE regimen, with treatment intervals adjusted by 4 weeks, up to a maximum of 16 weeks. Various laboratory biomarkers and optical coherence tomography parameters were evaluated. Patients were classified into the extension failure group if they had ≥ 1 treatment interval decreased due to an increase in the central macular thickness compared to the previous visit and 18 patients were assigned to this group. In multivariate logistic analyses, presence of microaneurysms and prominent middle limiting membrane (p-MLM) sign, increased initial external limiting membrane (ELM) disruption, and higher total cholesterol were correlated with inhibiting a sustained extension in the injection interval (P = 0.015, P = 0.032, P = 0.037, P = 0.009, respectively). Therefore, in the patients with ME secondary to BRVO with these risk factors, early consideration of frequent injection may improve treatment outcome.

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.

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.

AQUEOUS HUMOR CYTOKINE LEVELS AND REBOUND MACULAR EDEMA AFTER CONBERCEPT TREATMENT IN PATIENTS WITH CENTRAL RETINAL VEIN OCCLUSION

PURPOSE

This study aimed to investigate the effect of intravitreal conbercept (IVC) injections on the aqueous humor concentrations of angiogenic and inflammatory cytokines in patients with macular edema (ME) due to central retinal vein occlusion and to determine whether changes in cytokine levels after IVC are associated with the development of rebound ME.

METHODS

Forty-nine patients with ME caused by central retinal vein occlusion were included in this retrospective study. Monthly doses of IVC were administered for three months, followed by a Pro Re Nata dosing regimen. Rebound ME was defined as ≥110% increase in the foveal thickness compared with the baseline. Whenever injections were administered, aqueous humor samples were obtained. Multiplex bead assay was used to measure seven angiogenic and inflammatory cytokines in aqueous humor samples.

RESULTS

At baseline, patients with central retinal vein occlusion showed significantly higher aqueous humor concentrations of vascular endothelial growth factor, placental growth factor, monocyte chemoattractant protein-1, platelet-derived growth factor-AA, IL-6, IL-8, and IL-12. At 1-month and 2-month follow-up after IVC, significantly decreased concentrations of all cytokines were observed. During the 12-month follow-up period, 6 of the 49 eyes (12.2%) showed rebound ME after IVC. Patients with rebound ME showed significantly elevated levels of inflammatory but not angiogenic cytokines.

CONCLUSION

Angiogenic and inflammatory cytokines were overexpressed in patients with ME caused by central retinal vein occlusion. Conbercept treatment influenced the concentrations of various inflammatory cytokines and reduced aqueous vascular endothelial growth factor and placental growth factor concentrations. Rebound ME may occur due to disruption of the balance between angiogenic and inflammatory cytokines and an accompanying excess of inflammatory cytokines but not angiogenic cytokines, after antivascular endothelial growth factor therapy.

Comparison of the Effect of Intravitreal Conbercept and Ranibizumab on Aqueous Humor Cytokines in Central Retinal Vein Occlusion-Related Macular Edema

Purpose: To analyze changes in the levels of angiogenic and inflammatory cytokines following the administration of intravitreal conbercept (IVC) or intravitreal ranibizumab (IVR) in patients with macular edema (ME) due to central retinal vein occlusion (CRVO). Methods: This retrospective study was conducted between June 2015 and January 2016 in The First Hospital of China Medical University. We administered 3 consecutive monthly doses of IVC (23 eyes) or IVR (19 eyes) in 42 eyes with CRVO-ME. At each injection, we collected aqueous humor samples and used multiplex bead assays to measure 7 angiogenic and inflammatory cytokines [vascular endothelial growth factor (VEGF), placental growth factor (PlGF), platelet-derived growth factor (PDGF)-AA, monocyte chemoattractant protein (MCP)-1, and interleukins (ILs)-6, 8, and 12]. Results: Visual acuity and ME improved significantly in both groups during the treatment period. Compared with the baseline, all the cytokine concentrations in the aqueous humor samples decreased significantly at 1 and 2 months after the initial dose of IVC or IVR. The improvement of visual acuity and ME and the changes of aqueous humor cytokine levels were similar in both groups. Concentrations of VEGF, PlGF, MCP-1, PDGF-AA, IL-6, IL-8, and IL-12 levels did not show significant intergroup differences after 1 month (P = 0.369, 0.312, 0.185, 0.353, 0.135, 0.487, and 0.337, respectively) and 2 months (P = 0.305, 0.376, 0.230, 0.519, 0.114, 0.960, and 0.830, respectively) of follow-up. Conclusion: IVC and IVR induced comparable improvements in clinical parameters, along with equivalent reductions in the concentrations of angiogenic and inflammatory cytokines in the aqueous humor.

Cytokines and Pathogenesis of Central Retinal Vein Occlusion

Central retinal vein occlusion (CRVO) causes macular edema and subsequent vision loss and is common in people with diseases such as arteriosclerosis and hypertension. Various treatments for CRVO-associated macular edema have been trialed, including laser photocoagulation, with unsatisfactory results. However, when the important pathogenic role of vascular endothelial growth factor (VEGF) in macular edema was identified, the treatment of CRVO was revolutionized by anti-VEGF therapy. However, despite the success of intraocular injection of anti-VEGF agents in many patients with CRVO, some patients continue to suffer from refractory or recurring edema. In addition, the expression of inflammatory cytokines increases over time, causing more severe inflammation and a condition that is increasingly resistant to anti-VEGF therapy. This indicates that the pathogenesis of macular edema in CRVO is more complex than originally thought and may involve factors or cytokines associated with inflammation and ischemia other than VEGF. CRVO is also associated with leukocyte abnormalities and a gradual reduction in retinal blood flow velocity, which increase the likelihood of it developing from the nonischemic type into the more severe ischemic type; in turn, this results in excessive VEGF expression and subsequent neovascular glaucoma. Here, we review the role of different factors and cytokines involved in CRVO pathogenesis and propose a mechanism that holds promise for the development of novel therapies.

Topical Triamcinolone Acetonide-Loaded Liposomes as Primary Therapy for Macular Edema Secondary to Branch Retinal Vein Occlusion: A Pilot Study

Purpose: To explore safety and therapeutic efficacy of a topical ophthalmic triamcinolone acetonide-loaded liposome formulation (TA-LF) as primary therapy in patients with macular edema (ME) secondary to branch retinal vein occlusion (BRVO). Methods: Twelve eyes of 12 patients with ME secondary to BRVO were exposed to a topical instillation of 1 drop of TA-LF (TA 0.2%) 6 times a day for 12 weeks to evaluate safety and efficacy. Best corrected visual acuity (BCVA) intraocular pressure (IOP), slit lamp examination, and central foveal thickness (CFT) were analyzed at every visit. In addition, the morphology of TA-LF was analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results: Patients presented a significant improvement of BCVA and CFT without significant IOP modification (P = 0.94). Treated eyes showed BCVA improvement from 40 ± 12.05 to 64.83 ± 15.97 letters and CFT reduction from 682.91 ± 278.60 to 271.58 ± 57.66 μm after 12 weeks of TA-LF therapy (P < 0.001). No adverse events, including IOP rising, were registered. SEM analysis of liposomal formulations showed that liposome (LP) size depends on its concentration. As the concentration of TA increased, the average size of LPs and the number of larger particles increased as well. TEM study displayed that LP formulation efficiently solubilizes TA crystals in nanoparticles and encapsulates them. Conclusion: LPs can function as nanocarriers of TA and they could be used as topical ophthalmic primary therapy instead of intravitreal drugs in patients with ME secondary to BRVO.

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

PURPOSE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Changes in Aqueous and Vitreous Inflammatory Cytokine Levels in Retinal Vein Occlusion: A Systematic Review and Meta-analysis

Purpose:

Evidence suggests that inflammatory cytokines not only play a role in the pathogenesis of retinal vein occlusion (RVO) but also may be useful as biomarkers to predict disease severity and response to treatment. We aimed to quantitatively summarize data on inflammatory cytokines associated with RVO.

Methods:

A systematic search of peer-reviewed English-language articles was performed without year limitation up to August 19, 2019. Studies were included if they provided data on aqueous or vitreous cytokine concentrations in patients with RVO. Data were extracted from 116 studies that encompassed 3242 study eyes with RVO and 1402 control eyes. Effect sizes were generated as standardized mean differences (SMDs) of cytokine concentrations between patients with RVO vs controls.

Results:

Among the 4644 eyes in 116 studies, aqueous and vitreous concentrations (SMD, 95% CI, and P value) of interleukin (IL)-6 (aqueous: 1.23, 0.65 to 1.81, P < .001 vitreous: 0.70, 0.49 to 0.90, P < .001), IL-8 (aqueous: 1.11, 0.73 to 1.49, P < .001; vitreous: 1.19, 0.73 to 1.65, P < .001), monocyte chemoattractant protein 1(aqueous: 1.22, 0.72 to 1.72, P < .001; vitreous 1.42, 0.92 to 1.91, P < .001), vascular endothelial growth factor (VEGF) (aqueous: 1.52, 1.09 to 1.94, P < .001; vitreous: 0.99, 0.78 to 1.21, P < .001) were significantly higher in patients with RVO than in healthy controls. Only aqueous concentrations of IL-10 (0.81, 0.45 to 1.18, P < .001), angiopoietin 4 (1.96, 0.92 to 3.00, P < .001), and platelet-derived growth factor (PDGF)-AA (0.82, 0.35 to 1.30, P < .001) were significantly higher in patients with RVO than in healthy controls. Only the vitreous concentration of soluble intercellular adhesion molecule-1 (sICAM-1) (1.23, 0.83 to 1.63, P < .001) was significantly higher in patients with RVO. No differences, failed sensitivity analyses, or insufficient data were found between patients with RVO and healthy controls for the concentrations of the remaining cytokines.

Conclusions:

Several cytokines in addition to VEGF have the potential to be useful biomarkers and therapeutic targets in RVO.

Cytokines and the Pathogenesis of Macular Edema in Branch Retinal Vein Occlusion

Branch retinal vein occlusion (BRVO) is a very common retinal vascular problem in patients with lifestyle-related diseases, such as hypertension and arteriosclerosis. In patients with BRVO, development of macular edema is the main cause of visual impairment. BRVO is still a controversial condition in many respects. Over the years, various methods such as laser photocoagulation have been tried to treat macular edema associated with BRVO, but the results were not satisfactory. After vascular endothelial growth factor (VEGF) was found to have an important role in the pathogenesis of macular edema in BRVO patients, treatment of this condition was revolutionized by development of anti-VEGF therapy. Although macular edema improves dramatically following intraocular injection of anti-VEGF agents, repeated recurrence and resistance of edema is a major problem in some BRVO patients. This suggests that factors or cytokines other than VEGF may be associated with inflammation and retinal hypoxia in BRVO and that the pathogenesis of macular edema is complicated. The present review assesses the role of various factors and cytokines in the pathogenesis of macular edema associated with BRVO. We present a mechanism that is not only plausible but should also be useful for developing new therapeutic strategies.

Comprehensive analysis of vitreous chemokines involved in ischemic retinal vein occlusion

PURPOSE

To investigate vitreous levels of chemokines in eyes with ischemic retinal vein occlusion (RVO).

METHODS

The vitreous humor was collected at the start of 23-gauge pars plana vitrectomy from patients with ischemic RVO and patients with idiopathic preretinal membranes (PRMs) and idiopathic macular holes (IMHs). The levels of 40 different chemokines were measured using magnetic color-bead-based multiplex assay. The chi-square test was performed for clinical variables such as sex, and the Mann-Whitney U test was performed to evaluate the differences in the chemokine levels between the RVO group and the control group.

RESULTS

Vitreous humor was collected from 20 controls and 25 subjects with ischemic RVO. C-C motif ligand 17 (CCL17) was unmeasurable in more than 70% of the samples. The levels of 29 of 39 chemokines were statistically significantly elevated in the RVO group compared with the control group, including CCL21, C-X-C motif ligand (CXCL) 13, CCL27, CCL24, CX3CL1, CXCL6, interferon-gamma (IFN-γ), interleukin (IL) 1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-16, CXCL10, CXCL11, CCL8, CCL7, CCL13, CCL22, macrophage migration inhibitory factor (MIF), CXCL9, CCL3, CCL15, CCL20, CCL19, CCL23, CCL25, and tumor necrosis factor-alpha (TNF-α). Among the 29 elevated chemokines, we found that the levels of three chemokines (IL-8, CXCL9, and TNF-α) showed a more than six-fold increase in the RVO eyes versus controls, and CXCL9 expression showed the greatest change of all tested chemokines.

CONCLUSIONS

Dozens of chemokines were found to be elevated in the vitreous of RVO eyes complicated with vitreous hemorrhage, suggesting that inflammation is severe in the ischemic retina. The knowledge of specific upregulation of chemokines in ischemic RVO could allow more targeted future therapies.

Posterior subtenon infusion of triamcinolone acetonide as adjunctive treatment to panretinal photocoagulation using pattern scan laser for diabetic retinopathy

PURPOSE

To estimate the effect of sub-Tenon's capsule triamcinolone acetonide injection (STTA) combined with panretinal photocoagulation (PRP) using pattern scan laser (PSL) for high risk non-proliferative diabetic retinopathy (NPDR), in terms of the inflammation and the progression of diabetic macular edema (DME).

STUDY DESIGN

Retrospective comparative analysis.

METHODS

NPDR patients who underwent PRP using PSL with (STTA+PSL group, n=24) or without (PSL group, n=19) pretreatment of STTA were enrolled. We measured anterior flare intensity (AFI) and central retinal thickness (CRT) at day of STTA (day 0), and at 1, 3, 7, 11 and 15 weeks.

RESULTS

The CRT of the STTA+PSL group was significantly lower than that of the PSL group at 7 (308.15±69.16 μm versus 340.21±77.91 μm, p = 0.04), 11 (283.8±60.75 μm versus 335.7±67.70 μm, p = 0.01) and 15 weeks (281.13±35.29 μm versus 316.58±54.89 μm, p = 0.02). AFI levels in the STTA+PSL group were significantly lower than those in the PSL group at 11 (10.47±3.40 versus 15.85±8.38, p = 0.007) and 15 weeks (11.38±3.31 versus 14.37±3.85, p = 0.009). The significant improvement in CRT from baseline was noticed through the observational periods in STTA+PSL group, but not in the PSL group.

CONCLUSION

Pretreatment of STTA has the potential to not only prevent the worsening of DME, but also reduce the CRT and AFI of eyes with NPDR after PRP using PSL.

Advanced glycation endproducts link inflammatory cues to upregulation of galectin-1 in diabetic retinopathy

Diabetic retinopathy (DR) is an inflammatory and progressive vaso-occlusive disease resulting in angiogenesis. Galectin-1 is a hypoxia-induced angiogenic factor associated with cancer and proliferative DR. Here we reveal a significant upregulation of galectin-1 in eyes of DR patients along with progression of clinical stages beginning from the pre-ischemic, inflammatory stage with diabetic macular edema, but not in eyes with non-diabetic retinal vascular occlusions. As for its regulatory mechanism unrelated to hypoxia but selective to DR, in vitro galectin-1/LGALS1 expression was shown to increase after application to Müller glial cells with interleukin (IL)-1β, which was induced in monocyte-derived macrophages and microglial cells via toll-like receptor (TLR) 4 signaling stimulated by advanced glycation endproducts (AGE). In vivo inhibition of AGE generation with aminoguanidine, macrophage depletion with clodronate liposomes, and antibody-based blockade of Il-1β and Tlr4 attenuated diabetes-induced retinal Lgals1 expression in mice. Fibrovascular tissues from proliferative DR eyes were immunoreactive for AGE, TRL4 and IL-1β in macrophages, and IL-1β receptor-positive glial cells expressed galectin-1. Therefore, diabetes-induced retinal AGE accumulation was suggested to activate IL-1β-related inflammatory cues in macrophages followed by Müller cells, linking to galectin-1 upregulation in human DR with time. Our data highlight AGE-triggered inflammation as the DR-selective inducer of galectin-1.

New Developments in the Classification, Pathogenesis, Risk Factors, Natural History, and Treatment of Branch Retinal Vein Occlusion

For years, branch retinal vein occlusion is still a controversial disease in many aspects. An increasing amount of data is available regarding classification, pathogenesis, risk factors, natural history, and therapy of branch retinal vein occlusion. Some of the conclusions may even change our impression of branch retinal vein occlusion. It will be beneficial for our doctors to get a deeper understanding of this disease and improve the treatment skills. The aims of this review is to collect the information above and report new ideas especially from the past a few years.