Vitreous Mediators after Intravitreal Bevacizumab or Triamcinolone Acetonide in Eyes with Proliferative Diabetic Retinopathy

Suppressing Inflammation for the Treatment of Diabetic Retinopathy and Age-Related Macular Degeneration: Dazdotuftide as a Potential New Multitarget Therapeutic Candidate

Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are major causes of blindness globally. The primary treatment option for DME and neovascular AMD (nAMD) is anti-vascular endothelial growth factor (VEGF) compounds, but this treatment modality often yields insufficient results, and monthly injections can place a burden on the health system and patients. Although various inflammatory pathways and mediators have been recognized as key players in the development of DR and AMD, there are limited treatment options targeting these pathways. Molecular pathways that are interlinked, or triggers of multiple inflammatory pathways, could be promising targets for drug development. This review focuses on the role of inflammation in the pathogenesis of DME and AMD and presents current anti-inflammatory compounds, as well as a potential multitarget anti-inflammatory compound (dazdotuftide) that could be a candidate treatment option for the management of DME and AMD.

Substance P Alleviates Retinal Pigment Epithelium Dysfunction Caused by High Glucose-Induced Stress

When the retina is constantly affected by high glucose (HG) due to diabetes, the barrier function of the retinal pigment epithelium (RPE) is impaired, accompanied by unnecessary vascularization. This eventually leads to the development of diabetic retinopathy (DR). This study investigated the recovery effect of substance P (SP) on RPE injured by HG. RPE was treated with HG for 24 h, and HG-induced cellular injuries were confirmed. SP was added to the dysfunctional RPE. Compared to RPE in low glucose (LG) conditions, HG-damaged RPE had large, fibrotic cell shapes, and its cellular viability decreased. HG treatment reduced tight junction protein expression levels and caused oxidative stress by interrupting the antioxidant system; this was followed by inflammatory factor intracellular adhesion molecule-1 (ICAM-1), Monocyte chemotactic protein-1 (MCP-1), and angiogenesis factor vascular endothelial growth factor (VEGF) expression. SP treatment contributed to RPE recovery by enhancing cell viability, tight junction protein expression, and RPE function under HG conditions, possibly by activating the Akt signaling pathway. Importantly, SP treatment reduced ICAM-1, MCP-1, and VEGF expression. Collectively, SP activated survival signals to suppress oxidative stress and improve retinal barrier function in RPE, accompanied by immune suppression. This suggests the possible application of SP to diabetic retinal injuries.

Anti-vascular endothelial growth factor for proliferative diabetic retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) is an advanced complication of diabetic retinopathy that can cause blindness. It consists of the presence of new vessels in the retina and vitreous haemorrhage. Although panretinal photocoagulation (PRP) is the treatment of choice for PDR, it has secondary effects that can affect vision. Anti-vascular endothelial growth factor (anti-VEGF), which produces an inhibition of vascular proliferation, could improve the vision of people with PDR.

OBJECTIVES

To assess the effectiveness and safety of anti-VEGFs for PDR and summarise any relevant economic evaluations of their use.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 6); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov, and the WHO ICTRP. We did not use any date or language restrictions. We last searched the electronic databases on 1 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing anti-VEGFs to another active treatment, sham treatment, or no treatment for people with PDR. We also included studies that assessed the combination of anti-VEGFs with other treatments. We excluded studies that used anti-VEGFs in people undergoing vitrectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, and assessed the risk of bias (RoB) for all included trials. We calculated the risk ratio (RR) or the mean difference (MD), and 95% confidence intervals (CI). We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 15 new studies in this update, bringing the total to 23 RCTs with 1755 participants (2334 eyes). Forty-five per cent of participants were women and 55% were men, with a mean age of 56 years (range 48 to 77 years). The mean glycosylated haemoglobin (Hb1Ac) was 8.45% for the PRP group and 8.25% for people receiving anti-VEGFs alone or in combination. Twelve studies included people with PDR, and participants in 11 studies had high-risk PDR (HRPDR). Twelve studies were of bevacizumab, seven of ranibizumab, one of conbercept, two of pegaptanib, and one of aflibercept. The mean number of participants per RCT was 76 (ranging from 15 to 305). Most studies had an unclear or high RoB, mainly in the blinding of interventions and outcome assessors. A few studies had selective reporting and attrition bias. No study reported loss or gain of 3 or more lines of visual acuity (VA) at 12 months. Anti-VEGFs ± PRP probably increase VA compared with PRP alone (mean difference (MD) -0.08 logMAR, 95% CI -0.12 to -0.04; I2 = 28%; 10 RCTS, 1172 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP may increase regression of new vessels (MD -4.14 mm2, 95% CI -6.84 to -1.43; I2 = 75%; 4 RCTS, 189 eyes; low-certainty evidence) and probably increase a complete regression of new vessels (RR 1.63, 95% CI 1.19 to 2.24; I2 = 46%; 5 RCTS, 405 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP probably reduce vitreous haemorrhage (RR 0.72, 95% CI 0.57 to 0.90; I2 = 0%; 6 RCTS, 1008 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP may reduce the need for vitrectomy compared with eyes that received PRP alone (RR 0.67, 95% CI 0.49 to 0.93; I2 = 43%; 8 RCTs, 1248 eyes; low-certainty evidence). Anti-VEGFs ± PRP may result in little to no difference in the quality of life compared with PRP alone (MD 0.62, 95% CI -3.99 to 5.23; I2 = 0%; 2 RCTs, 382 participants; low-certainty evidence). We do not know if anti-VEGFs ± PRP compared with PRP alone had an impact on adverse events (very low-certainty evidence). We did not find differences in visual acuity in subgroup analyses comparing the type of anti-VEGFs, the severity of the disease (PDR versus HRPDR), time to follow-up (< 12 months versus 12 or more months), and treatment with anti-VEGFs + PRP versus anti-VEGFs alone. The main reasons for downgrading the certainty of evidence included a high RoB, imprecision, and inconsistency of effect estimates.

AUTHORS' CONCLUSIONS

Anti-VEGFs ± PRP compared with PRP alone probably increase visual acuity, but the degree of improvement is not clinically meaningful. Regarding secondary outcomes, anti-VEGFs ± PRP produce a regression of new vessels, reduce vitreous haemorrhage, and may reduce the need for vitrectomy compared with eyes that received PRP alone. We do not know if anti-VEGFs ± PRP have an impact on the incidence of adverse events and they may have little or no effect on patients' quality of life. Carefully designed and conducted clinical trials are required, assessing the optimal schedule of anti-VEGFs alone compared with PRP, and with a longer follow-up.

Serum and vitreous vascular endothelial growth factor levels in diabetic retinopathy

PURPOSE

To research whether serum vascular endothelial growth factor (VEGF) levels could be used to evaluate diabetic retinopathy (DR) progression and to compare vitreous VEGF levels after injections of intravitreal bevacizumab (IVB), ranibizumab (IVR), and triamcinolone acetonide (IVTA) in proliferative diabetic retinopathy (PDR).

METHODS

We enrolled a total of 91 eyes of 89 subjects (70 eyes of 68 diabetics and 21 eyes of 21 non-diabetic controls). The diabetic subjects were divided into three groups as PDR (n = 28), non-proliferative diabetic retinopathy (n = 20), and no-DR (n = 20). Eyes with PDR (n = 31) were injected with IVB (n = 7), IVR (n = 10), or IVTA (n = 6) 3 days before vitrectomy, and eight eyes did not receive an injection. Serum and vitreous samples were collected before vitrectomy and analyzed using ELISA.

RESULTS

We found the severity of retinopathy was not correlated with serum VEGF levels (P = .919, ρ = -0.011). Compared with the controls, vitreous VEGF was higher in the PDR (P < .001), whereas serum VEGF did not differ (P = .99). The controls had lower vitreous VEGF than the IVB, IVR, and no-injection subgroups (P = .01, P < .001, and P = .04, respectively). Vitreous VEGF was similar among the injected and no-injection subgroups (P = .17).

CONCLUSIONS

Serum VEGF levels may not directly reflect retinopathy progression. Neither IVB, IVR nor IVTA could eliminate vitreous VEGF levels within 3 days before vitrectomy.

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

BACKGROUND

Diabetic retinopathy is a major complication of diabetes mellitus, where in its most advanced form ischemic changes lead to the development of retinal neovascularization, termed proliferative diabetic retinopathy (PDR). While the development of PDR is often associated with angiogenic and inflammatory cytokines, studies differ on which cytokines are implicated in disease pathogenesis and on the strength of these associations. We therefore conducted a systematic review and meta-analysis to quantitatively assess the existing body of data on intraocular cytokines as biomarkers in PDR.

METHODS

A comprehensive search of the literature without year limitation was conducted to January 18, 2021, which identified 341 studies assessing vitreous or aqueous cytokine levels in PDR, accounting for 10379 eyes with PDR and 6269 eyes from healthy controls. Effect sizes were calculated as standardized mean differences (SMD) of cytokine concentrations between PDR and control patients.

RESULTS

Concentrations (SMD, 95% confidence interval, and p-value) of aqueous IL-1β, IL-6, IL-8, MCP-1, TNF-α, and VEGF, and vitreous IL-2, IL-4, IL-6, IL-8, angiopoietin-2, eotaxin, erythropoietin, GM-CSF, GRO, HMGB-1, IFN-γ, IGF, IP-10, MCP-1, MIP-1, MMP-9, PDGF-AA, PlGF, sCD40L, SDF-1, sICAM-1, sVEGFR, TIMP, TNF-α, and VEGF were significantly higher in patients with PDR when compared to healthy nondiabetic controls. For all other cytokines no differences, failed sensitivity analyses or insufficient data were found.

CONCLUSIONS

This extensive list of cytokines speaks to the complexity of PDR pathogenesis, and informs future investigations into disease pathogenesis, prognosis, and management.

Monoclonal antibodies in diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR), as one of the main complications of diabetes, is among the leading causes of blindness and visual impairment worldwide.

AREAS COVERED

Current clinical therapies include photocoagulation, vitrectomy, and anti-vascular endothelial growth factor (VEGF) therapies. Bevacizumab and ranibizumab are two monoclonal antibodies (mAbs) inhibiting angiogenesis. Intravitreal ranibizumab and bevacizumab can decrease the rate of blindness and retinal thickness, and improve visual acuity whether as monotherapy or combined with other treatments. They can increase the efficacy of other treatments and decrease their adverse events. Although administered intravitreally, they also might enter the circulation and cause systemic effects. This study is aimed to review our current knowledge about mAbs, bevacizumab and ranibizumab, in DR including superiorities, challenges, and limitations. Meanwhile, we tried to shed light on new ideas to overcome these limitations. Our latest search was done in April 2021 mainly through PubMed and Google Scholar. Relevant clinical studies were imported.

EXPERT OPINION

Future direction includes detection of more therapeutic targets considering other components of DR pathophysiology and shared pathogenesis of DR and neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease, the treat-and-extend regimen, and new ways of drug delivery and other routes of ocular drug administration.

Comparison of before versus after intravitreal bevacizumab injection, growth factor levels and fibrotic markers in vitreous samples from patients with proliferative diabetic retinopathy

PURPOSE

In diabetic retinopathy patients, intravitreal bevacizumab (IVB) injections are widely used to facilitate dissection of retinal fibrovascular membranes during surgery, reduce the rate of perioperative hemorrhage, and prevent recurrent neovascularization. Previous studies have shown that IVB may worsen fibrosis and thereby impair vision. The aim of this study was to determine which markers are associated with fibrosis.

METHODS

Twenty-three patients with proliferative diabetic retinopathy (PDR) underwent pars plana vitrectomy (PPV) with IVB pretreatment for intraocular hemorrhage (IOH) and/or tractional retinal detachment (TRD). Vitreous samples were obtained at the time of IVB injection and again at the beginning of PPV, about a week later. Using Western blot analysis, the concentrations of vascular endothelial growth factor (VEGF), placental growth factor (PIGF), insulin like growth factor-1 (IGF-1), angiogenin-1 (Ang-1), and vascular endothelial cadherin (VE-cadherin) were measured in vitreous samples.

RESULTS

After treatment with IVB, VEGF, PIGF, and VE-cadherin concentrations in the vitreous significantly decreased (p < 0.001, p < 0.001, and p = 0.001, respectively), whereas the concentrations of IGF-1 increased (p = 0.001). There were no significant changes in Ang-1 concentrations in the vitreous after IVB injection (p = 0.732). There were no statistically significant differences in VEGF-A, PIGF, VE-cadherin, IGF, and Ang-1 levels before and after IVB injection when the IOH and TRD groups underwent subgroup analysis (p = 0.696, p = 0.516, p = 0.498, p = 0.188, and p = 0.243, respectively).

CONCLUSION

The levels of VEGF and other cytokines changed in the vitreous after IVB. The adverse effects associated with IVB, such as fibrosis, may result from modulation of vitreous cytokine concentrations. In the treatment of PDR, drugs that optimize the effects of PIGF, IGF-1, and VE-cadherin to reduce these side effects may be useful.

Involvement of Cytokines in the Pathogenesis of Diabetic Macular Edema

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

Intravitreal ranibizumab and dexamethasone implant injections as primary treatment of diabetic macular edema: simultaneously double protocol

PURPOSE

To assess the 12-month efficacy and safety of simultaneously administered intravitreal dexamethasone implant (DEX implant) and ranibizumab (simultaneous double protocol) injections in comparison with ranibizumab monotherapy as the first-line treatment of diabetic macular oedema (DMO).

METHODS

Prospective, consecutive, clinical interventional study. Patients were randomized into two groups: 24 naive DMO patients (34 eyes) who received simultaneous double-protocol therapy and 22 DMO patients (34 eyes) who received ranibizumab monotherapy were included. Monthly ranibizumab (0.5 mg) was administered for the first 6 months and later on, an as-needed treatment basis. DEX implant injection was performed at any time during the loading dose of the three consecutive monthly injections of ranibizumab, and with as-needed reinjections of ranibizumab from 6th month onwards. Change in visual acuity was the primary efficacy endpoint. Secondary efficacy endpoints were a gain of ≥15 letters and a change in the central foveal thickness.

RESULTS

Mean BCVA increased from baseline to month 12 in the simultaneously double-protocol therapy group compared with the ranibizumab monotherapy group (21.6 versus 9.6 letters [P < 0.001]). The corresponding proportions of eyes gaining ≥15 letters were 60% versus 29.4% (P < 0.0001). Moreover, the mean reductions in the central foveal thickness were 413 versus 282 µm (P = 0.001). At 12 month, the simultaneous double-protocol therapy decreased a significant number of foveal cysts and subfoveal neuroretinal detachment compared with those by ranibizumab monotherapy.

CONCLUSIONS

The simultaneous addition of DEX implant at any time during the three monthly loading doses of ranibizumab in patients with DMO significantly improved the visual outcomes and revealed superior anatomic outcomes than those with the ranibizumab monotherapy.

Vascular endothelial growth factor concentration in vitreous humor of patients with severe proliferative diabetic retinopathy after intravitreal injection of conbercept as an adjunctive therapy for vitrectomy

Background

Proliferative diabetic retinopathy (PDR) is a progressive stage of diabetic retinopathy featured by the formation of neovascular and proliferative membrane. Vascular endothelial growth factor (VEGF) acts as a pivot factor in the development of neovascularization. This study was to investigate the changes of intravitreal VEGF concentrations of severe PDR after intravitreal injection of conbercept (IVC) and its potential advantages to the following vitrectomy.

Methods

This was a prospective, interventional, randomized controlled study. Sixty eyes (60 patients) with severe PDR and 20 eyes from 20 patients with rhegmatogenous retinal detachment complicated with proliferative vitreoretinopathy were enrolled in this study. PDR eyes were randomly assigned to three groups by sortation randomization method with 20 eyes in each based on the interval of preoperative IVC (group A: 7 days, group B: 14 days, group C: non-IVC). Another 20 eyes without diabetes were enrolled as the non-diabetic control group (group D), receiving PPV directly. Vitreous specimens of all 80 patients were collected and evaluated afterwards. The intravitreal VEGF concentration of the four groups, and the total surgical time and the intraoperative bleeding rate of the PDR groups were recorded.

Results

The mean intravitreal VEGF concentrations of groups A–D were 66.6 ± 43.3, 93.1 ± 52.3, 161.4 ± 106.1 and 1.8 ± 1.2 pg/mL, respectively. It increased significantly in PDR patients (groups A, B and C) (P = 0.002, <0.001, and <0.001, respectively). PDR patients with preoperative IVC (groups A and B) presented significantly lower VEGF concentrations (P < 0.001 and 0.001), intraoperative bleeding rates (P = 0.004) and total surgical time (P < 0.001, P = 0.003) compared with group C. No statistical differences were presented between groups A and B on the three parameters.

Conclusion

Seven days and 14 days of preoperative IVC are equally efficient and safe for the vitrectomy of severe PDR patients through decreasing vitreous VEGF concentrations, intraoperative bleeding rate and total surgical times.

Choroidal Thickness After Dexamethasone Implant or Aflibercept in Patients with Diabetic Macular Edema Persistent to Ranibizumab

Purpose: This study aims to compare subfoveal choroidal thicknesses (SFCTs) after intravitreal dexamethasone (IVD) or intravitreal aflibercept (IVA) treatment in patients with persistent diabetic macular edema (DME) unresponsive to intravitreal ranibizumab (IVR). Methods: The study consisted of patients with DME unresponsive to IVR treatment in which 37 were administered 1 dose IVD (group A) and 34 patients who were administered 3 doses of IVA (group B), as well as 35 healthy individuals (group C). Detailed ophthalmological examination and optical coherence tomography parameters of group A and group B, including central retinal thickness and SFCT, were retrospectively evaluated before and after treatment. Results from preinjection, and 1, 2, and 3 months after injection were analyzed. Results of group A and group B were compared within themselves and also compared with group C. Results: SFCT measurements were compared within group A and group B (1 = preinjection; 2 = 1 month postinjection; 3 = 2 months postinjection; 4 = 3 months postinjection). There was significant thinning in SFCT between 1-2, 1-3, 1-4, 2-3, 2-4, and 3-4 time intervals within both group A and group B (both P < 0.001). Comparison of SFCT measurements showed preinjection, 1-, and 2-month values of group A were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.09). Preinjection, 1-, and 2-month values of group B were significantly thicker than those of group C (P < 0.001), whereas there was no significant difference between 3-month values (P = 0.06). Conclusions: Three month follow-up showed thinning in SFCT measurements in patients with persistent DME unresponsive to IVR who were applied IVD or IVA treatment.

Evaluation of Local Injection of Bevacizumab against Triple-Negative Breast Cancer Xenograft Tumors

Background and objective:

Bevacizumab (BVZ) is a recombinant humanized antibody that inhibits the vascular endothelial growth factor A (VEGFA) and is used for the treatment of various types of cancer. BVZ is primarily given by the intravenous drip (I.V.), which often leads to low efficacy and various side effects. Therefore, the present study was to evaluate the effect of local delivery of BVZ against triple-negative breast cancer (TNBC) xenograft tumors.

Methods:

Mice 4T1 TNBC cells were engrafted in female BALB/c mice. After the tumors reached about 5 mm (diameter), animals were treated with BVZ through the local injection from four directions around the tumors. The tumor growth, survival and potential mechanisms of action were evaluated.

Results:

The growth and microvessel density of engrafted tumors were dramatically reduced with the tumor inhibition rate of 32.8 ± 3%. No obvious side effects were observed. The expression of VEGFA, VEGF receptor (VEGFR), matrix metalloproteinase (MMP)-2, MMP-9, Delta-like ligand 4 (DLL4) and Integrin-5 was significantly reduced in TNBC tumor tissues. In contrast, tissue inhibitor of matrix metalloproteinase (TIMP)-2 was significantly upregulated in xenograft tumors. Additionally, local delivery of BVZ led to the reduction of VEGFA and tumor necrosis factor (TNF)-alpha in the serum. Protein-protein interaction (PPI) analysis revealed that the proteins altered by the local delivery of BVZ were associated with angiogenesis and regulation of cell migration.

Conclusion:

This study provided evidence associated with local delivery of BVZ against TNBC tumors supporting the use of BVZ local injections to overcome some of the disadvantages associated with I.V. therapy with BVZ.

Preoperative Timing of Intravitreal Bevacizumab Injection for Proliferative Diabetic Retinopathy Patients

OBJECTIVE

To evaluate the changes in aqueous concentrations of inflammatory cytokines and fibrosis-related factors, and to detect the expression of vascular endothelial growth factor (VEGF) and proliferating cells in fibrovascular membranes (FVMs) of patients with proliferative diabetic retinopathy (PDR) after injection of intravitreal bevacizumab (IVB).

METHODS

Forty-two eyes of 42 patients with PDR, including 28 eyes that received IVB (1.25 mg) 2, 5, and 14 days before pars plana vitrectomy (PPV), and 14 eyes without IVB, were enrolled, in addition to 10 eyes of 10 patients with nondiabetic ocular diseases. Aqueous concentrations of inflammatory cytokines and fibrosis-related factors were analyzed by a multiplex bead assay. Fluorescence immunostaining was performed to examine the expression of VEGF and proliferating cells in the excised epiretinal membranes.

RESULTS

PDR eyes without IVB had the highest vitreous VEGF levels, and the level was statistically significant compared with that of PDR eyes that received IVB 2 days before surgery, PDR eyes that received IVB 5 days before surgery, and nondiabetic eyes (p = 0.011, p = 0.012, and p < 0.001, respectively). The expression of fibroblastic cells and connective tissue growth factor increased in epiretinal FVMs of the IVB group 21 days after treatment.

CONCLUSIONS

IVB injection may lead to a decrease in the intraocular concentrations of VEGF after 2-5 days and induce the formation of proliferation after 21 days, which suggests that PPV in PDR patients should take place within 1 week of the administration of preoperative IVB.

Optical coherence tomography findings predictive of response to treatment in diabetic macular edema

Objective

To evaluate the short-term efficacy of intravitreal bevacizumab (IVB) and posterior sub-tenon triamcinolone injections (PSTI) on the basis of spectral-domain optical coherence tomography (SD-OCT) patterns in diabetic macular edema (DME).

Methods

We retrospectively reviewed 73 eyes of 73 patients with DME. Based on the presence of serous retinal detachment (SRD), eyes were categorized into two groups, and either IVB or PSTI treatment was performed. Central macular thickness (CMT) and the degree of SRD were assessed preoperatively and 1 month postoperatively. The severity of intraretinal edema was approximated based on the distance from the external limiting membrane to the internal limiting membrane.

Results

In eyes with SRD, reduction of SRD was greater with IVB than with PSTI. Moreover, reduction of intraretinal edema was greater with PSTI than with IVB. In eyes without SRD, PSTI achieved greater CMT reduction, compared with IVB.

Conclusions

In DME patients with SRD, IVB achieved greater reduction of SRD, compared with PSTI; however, intraretinal edema responded more favorably to PSTI, regardless of the presence of SRD. Our results suggest that the classification of DME based on OCT findings may be useful to predict responses to IVB or PSTI treatments.

Management of diabetic macular edema in Japan: a review and expert opinion

Diabetic retinopathy is a frequent cause of visual impairment in working-age adults (≥ 30 years) and in Japan is most commonly observed in those aged 50-69 years. Diabetic macular edema (DME) is one of the main causes of vision disturbance in diabetic retinopathy, which is a clinically significant microvascular complication of diabetes. Anti-vascular endothelial growth factor (VEGF) therapy is becoming the mainstay of treatment for DME. However, to achieve sustained long-term improvement in visual acuity, conventional laser photocoagulation, vitrectomy and steroid therapy are also expected to play a role in the treatment of DME. This review summarizes the epidemiology and pathology of diabetic retinopathy and DME, evaluates the findings regarding the diagnosis and treatment of DME, and underscores the importance of systemic management of the disease in the context of the current health care situation in Japan. Finally, the unmet needs of patients with DME and prospects for research are discussed. The weight of evidence suggests that it is important to establish a multipronged treatment strategy centered on anti-VEGF therapy.

Aqueous vascular endothelial growth factor and clinical outcomes correlation after single intravitreal injection of bevacizumab in patients with neovascular age-related macular degeneration

Purpose

To evaluate the concentration of vascular endothelial growth factor (VEGF) in aqueous humor after a single intravitreal injection of bevacizumab (IVB) in eyes with neovascular age-related macular degeneration (AMD).

Methods

In this prospective interventional case series study, 24 eyes of 24 patients with types 1 and 2 choroidal neovascularization secondary to neovascular AMD were treated with a single intravitreal injection of bevacizumab. Aqueous humor samples were obtained before the intravitreal injection and at one week, one month, and three months follow-up periods. Best-corrected visual acuity (BCVA) and three spectral-domain optical coherence tomography parameters (central retinal thickness, macular volume and macular area) were also analyzed and correlated with VEGF expression at the baseline and each follow-up period.

Results

All of the ninety-six aqueous humor study taps were well tolerated by the study patients without adverse events. Increased VEGF levels (mean ± SD = 179.7 ± 88.3 pg/mL) were observed in the aqueous humor of all study patients before the intravitreal injection of bevacizumab. At all follow-up periods, compared to baseline, levels of VEGF significantly reduced (P < 0.0001), and BCVA significantly improved (P < 0.005). The lowest VEGF expression was observed at 1 week, and the greatest BCVA improvement occurred 1 month after treatment. At 1 month, central retinal thickness (CRT), macular volume (MV), and macular area (MA) significantly reduced compared to baseline (P < 0.0001, P = 0.0005, P = 0.007, P = 0.009, respectively). At 1 week and 3 months, although without statistical significance (P > 0.005), CRT, MV and MA also reduced in comparison to baseline.

Conclusions

Single intravitreal bevacizumab injection in eyes with neovascular AMD resulted in a substantial decrease of aqueous VEGF levels 1 week after treatment with the greatest improvement of clinical outcomes occurring at 1 month follow-up.

Effect of bevacizumab on the expression of fibrosis-related inflammatory mediators in ARPE-19 cells

AIM

To investigate the effect of anti-vascular epithelial growth factor (VEGF) agents on the expression of fibrosis-related inflammatory mediators under normoxic and hypoxic conditions, and to further clarify the mechanism underlying fibrosis after anti-VEGF therapy.

METHODS

Human retinal pigment epithelial (RPE) cells were incubated under normoxic and hypoxic conditions. For hypoxia treatment, CoCl₂ at 200 µmol/L was added to the media. ARPE-19 cells were treated as following: 1) control group: no treatment; 2) bevacizumab group: bevacizumab at 0.25 mg/mL was added to the media; 3) hypoxia group: CoCl₂ at 200 µmol/L was added to the media; 4) hypoxia+bevacizumab group: CoCl₂ at 200 µmol/L and bevacizumab at 0.25 mg/mL were added to the media. The expression of interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor (TNF)-α were evaluated using real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) at 6, 12, 24 and 48h.

RESULTS

Both mRNA and protein levels of IL-1β, IL-6 and IL-8 were statistically significantly higher in the bevacizumab group than in the control group at each time point, and TNF-α gene and protein expression was only significantly higher only at 24 and 48h (P<0.05). Under hypoxic conditions, bevacizumab significantly increased the expression of IL-1β, IL-6, IL-8 and TNF-α at 6, 12, 24 and 48h (P<0.05). IL-1β, IL-8 and TNF-α peaked at 24h and IL-6 peaked at 12h after the bevacizumab treatment under both normoxic and hypoxic conditions.

CONCLUSION

Treatment of ARPE-19 cells with bevacizumab can significantly increase the expression of fibrosis-related inflammatory mediators under both normoxic and hypoxic conditions. Inflammatory factors might be involved in the process of fibrosis after anti-VEGF therapy, and the up-regulation of inflammatory factors induced by anti-VEGF drugs might promote the fibrosis process.

Retinal pigment epithelium-secretome: A diabetic retinopathy perspective

Diabetic retinopathy is a major complication of diabetes mellitus that can lead to retinal vascular abnormalities and visual impairment. While retinal endothelial pathology is well studied, retinal pigment epithelium (RPE) layer modifications and the patho-physiological regulations are not widely understood. The RPE is a highly specialized pigmented layer regulating not only physiological functions such as transport of nutrients, ions, absorption of light, phagocytosis of photoreceptor membranes, but also secretion of a number of cytokines, chemokines, angiogenic and anti-angiogenic factors. The RPE secretome, though crucial in health and disease, remains elusive in diabetic retinopathy. A knowledge of these secreted factors would help explain and correlate the clinical phase of the disease aiding in improved disease management. A comprehensive knowledge of the secreted factors of the RPE is a potential tool for understanding the differential treatment regime of early diabetic retinopathy, diabetic proliferative retinopathy and diabetic macular edema. In this review, we have delineated the importance of factors secreted by the retinal pigment epithelium and its regulation in the pathogenesis of diabetic retinopathy.

Curcumolide reduces diabetic retinal vascular leukostasis and leakage partly via inhibition of the p38MAPK/NF-κ B signaling

Retinal inflammation in a hyperglycemic condition is believed to play a crucial role in the development of diabetic retinopathy, and targeting inflammatory mediators is a promising strategy for the control of diabetic retinopathy. Curcumolide, a novel sesquiterpenoid with a unique 5/6/5 tricyclic skeleton, was isolated from Curcuma wenyujin. In this study, we demonstrate that treatment with curcumolide alleviated retinal inflammatory activities both in vitro and in vivo in a STZ-induced diabetic rat model and in TNF-α-stimulated HUVECs. Curcumolide alleviated retinal vascular permeability and leukostasis and attenuated the overexpression of TNF-α and ICAM-1 in diabetic retinas. Moreover, curcumolide also inhibited inducible p38 MAPK and NF-κB activation and the subsequent induction of proinflammatory mediators. These data suggest potential treatment strategies against diabetic retinopathy, particularly in the early stages of the disease.

Vitreous levels of placental growth factor correlate with activity of proliferative diabetic retinopathy and are not influenced by bevacizumab treatment

PurposePlacental growth factor (PlGF) is a member of the VEGF family that plays an important role in experimental models of diabetic retinopathy and retinal neovascularization. We aimed to investigate whether vitreous levels of PlGF correlated with proliferative diabetic retinopathy (PDR) status, VEGF levels, and bevacizumab treatment. We also analysed PDR membranes to confirm the presence of the PlGF receptor, FLT1, in endothelial cells.MethodsThis was a case-control study: undiluted vitreous fluid samples were obtained from 28 active PDR patients without preoperative bevacizumab treatment, 21 active PDR patients with preoperative bevacizumab treatment, 18 inactive PDR patients, and 21 control patients. PlGF and VEGF levels in samples were determined by enzyme-linked immunosorbent assay. Immunohistochemistry for FLT1 was performed on human PDR membranes.ResultsCompared to control, vitreous PlGF levels were higher in both active PDR without bevacizumab (P<0.0001) and with bevacizumab (P<0.0001). There was no significant difference in PlGF between active PDR patients without and with bevacizumab (P=0.56). Compared to active PDR, PlGF levels were significantly reduced in inactive PDR (P=0.004). PlGF levels were highly correlated with VEGF levels in active PDR. VEGFR1 was expressed in endothelial cells in human PDR membranes.ConclusionThe strong correlation of PlGF levels with PDR disease status and expression of FLT1 in human PDR membranes suggest that PlGF has a pathogenic role in proliferative diabetic retinopathy. Therapeutic targeting of PlGF with agents like aflibercept may be beneficial.

The impact of ranibizumab on the level of intercellular adhesion molecule type 1 in the vitreous of eyes with proliferative diabetic retinopathy

PURPOSE

This study was to investigate the impact of ranibizumab on the level of intercellular adhesion molecule type 1 (ICAM-1) in the vitreous of eyes with PDR.

METHODS

This is an interventional case-control study. A total of 82 eyes from 82 patients who had undergone vitreous surgery for the treatment of retinal disorders were included. Twenty-two eyes with PDR received an intravitreal ranibizumab injection (IVR) 3-7 days before vitrectomy and were grouped as 'PDR with recent IVR' or Group 1. Sixteen eyes with PDR received IVR more than 7 days before vitrectomy and were grouped as 'PDR with remote IVR' or Group 2. Twenty-two matched PDR eyes did not receive IVR before vitrectomy and were grouped as 'PDR without IVR' or Group 3. Finally, 22 eyes from 22 patients with idiopathic macular pucker (IMP) served as the 'non-diabetic control' group, or Group 4. Vitreous samples were obtained at the time of vitrectomy from all eyes, and the levels of vascular endothelium growth factor (VEGF) and ICAM-1 were analysed using ELISA.

RESULTS

PDR without IVR (Group 3) had the highest vitreous VEGF concentration; the difference was significant compared with those in the PDR with recent IVR (Group 1), PDR with remote IVR (Group 2) and the non-diabetic control group (Group 4) (p < 0.001). Group 2 had a lower vitreous VEGF level than Group 1 (p = 0.041). Group 1 had the highest vitreous ICAM-1 levels (p < 0.001 versus. Groups 2, 3 and 4); Group 2 had a lower vitreous ICAM-1 level than Group 3 (p = 0.028).

CONCLUSION

The vitreous fluid level of ICAM-1 was significantly increased within 1 week of IVR administration, but markedly decreased after a week of administration in eyes with PDR. This suggests that leucostasis, vascular leakage and endothelial dysfunction may be amplified in the early days after IVR, but that a therapeutic effect of IVR in these processes may appear after 1 week of ranibizumab administration in eyes with PDR.

Effect of intravitreal dexamethasone implant on retinal and choroidal thickness in refractory diabetic macular oedema after multiple anti-VEGF injections

AimsTo investigate the effect of intravitreal dexamethasone implant (IVD) on central foveal thickness (CFT), choroidal thickness (CT) and its correlation with visual acuity in eyes with refractory diabetic macular oedema (DMO).MethodsThis was a retrospective interventional case-series. Thirty-five eyes of 35 patients were treated with a single injection of IVD because of refractory DMO with CFT over 300 μm, and persistent intraretinal and subretinal fluid despite of multiple intravitreal bevacizumab injections. Patients were followed-up for 6 months for the evaluation of CFT and subfoveal CT by spectral-domain optical coherence tomography.ResultsAll eyes (mean age: 59.4±12.35 years; 18 males, 17 females) had been previously treated with multiple bevacizumab injections and showed persistent DMO (mean number of injections 4.08±2.98) The preoperative logMAR BCVA was 0.49±0.24, which gradually improved to 0.46±0.32 at 6 months (P=0.652) and 26% gained two or more lines of Snellen visual acuity. At baseline, the mean CFT was 526.29±123.48 μm, which significantly improved to 316.15±100.09 μm at 3 months (P<0.001). However, CFT deteriorated to 457.07±136.53 μm at 6 months (P=0.051). Similarly, the mean preoperative subfoveal CT was 288.91±36.47 μm and it decreased to 266.85±30.93 μm at 3 months (P<0.01), but increased to 278.63±32.55 μm at 6 months (P=0.137). The reduction of CFT from baseline showed significant correlation with that of subfoveal CT at 3 months (P=0.041) and at 6 months (P=0.008).ConclusionsIn DMO refractory to multiple bevacizumab injections, IVD significantly reduced CFT and subfoveal CT, with BCVA improvement in one-fourth of the patients. The reduction of CFT showed significant correlation with reduction of subfoveal CT.

Elevated Levels of Cytokines Associated with Th2 and Th17 Cells in Vitreous Fluid of Proliferative Diabetic Retinopathy Patients

Macrophages are involved in low-grade inflammation in diabetes, and play pathogenic roles in proliferative diabetic retinopathy (PDR) by producing proinflammatory cytokines. T cells as well as other cells are also activated by proinflammatory cytokines, and infiltration into the vitreous of patients with PDR has been shown. In this study, we measured helper T (Th) cell-related cytokines in the vitreous of PDR patients to define the characteristics of Th-mediated immune responses associated with PDR. The study group consisted of 25 type 2 diabetic patients (25 eyes) with PDR. The control group consisted of 27 patients with epiretinal membrane (ERM), 26 patients with idiopathic macular hole (MH), and 26 patients with uveitis associated with sarcoidosis. Vitreous fluid was obtained at the beginning of vitrectomy, and centrifuging for cellular removals was not performed. Serum was also collected from PDR patients. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble sCD40L, and TNFα in the vitreous and serum samples were measured. Both percent detectable and levels of IL-4, IL-6, IL-17A, IL-21, IL-22, and TNFα in the vitreous were significantly higher than those in the serum in PDR patients. Vitreous levels of these cytokines and IL-31 were significantly higher in PDR than in ERM or MH patients. Vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα in PDR patients were also significantly higher than those of sarcoidosis patients. In PDR patients, vitreous IL-17A level correlated significantly with vitreous levels of IL-22 and IL-31, and especially with IL-4 and TNFα. Although it is unclear whether these cytokines play facilitative roles or inhibitory roles for the progression of PDR, the present study indicated that Th2- and Th17-related immune responses are involved in the pathogenesis of PDR.

Anti-vascular endothelial growth factor for proliferative diabetic retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) is a complication of diabetic retinopathy that can cause blindness. Although panretinal photocoagulation (PRP) is the treatment of choice for PDR, it has secondary effects that can affect vision. An alternative treatment such as anti-vascular endothelial growth factor (anti-VEGF), which produces an inhibition of vascular proliferation, could improve the vision of people with PDR.

OBJECTIVES

To assess the effectiveness and safety of anti-VEGFs for PDR.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 3), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2014), EMBASE (January 1980 to April 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 April 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing anti-VEGFs to another active treatment, sham treatment or no treatment for people with PDR. We also included studies that assessed the combination of anti-VEGFs with other treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data and assessed risk of bias for all included trials. We calculated the risk ratio (RR) or the mean difference (MD), and 95% confidence intervals (CI).

MAIN RESULTS

We included 18 RCTs with 1005 participants (1131 eyes) of whom 57% were men. The median number of participants per RCT was 40 (range 15 to 261). The studies took place in Asia (three studies), Europe (two studies), the Middle East (seven studies), North America (three studies) and South America (three studies). Eight RCTs recruited people eligible for PRP, nine RCTs enrolled people with diabetes requiring vitrectomy and one RCT recruited people undergoing cataract surgery. The median follow-up was six months (range one to 12 months). Seven studies were at high risk of bias and the remainder were unclear risk of bias in one or more domains.Very low quality evidence from one study of 61 people showed that people treated with bevacizumab and PRP were less likely to lose 3 or more lines of visual acuity at 12 months compared with people treated with PRP alone (RR 0.19, 95% CI 0.05 to 0.81). People treated with anti-VEGF had an increased chance of gaining 3 or more lines of visual acuity but the effect was imprecise and compatible with no effect or being less likely to gain vision (RR 6.78, 95% CI 0.37 to 125.95). No other study reported these two outcomes. On average, people treated with anti-VEGF (bevacizumab, pegaptanib or ranibizumab) had better visual acuity at 12 months compared with people not receiving anti-VEGF (MD -0.07 logMAR, 95% CI -0.12 to -0.02; 5 RCTs, 373 participants, low quality evidence). There was some evidence to suggest a regression of PDR with smaller leakage on fluorescein angiography but it was difficult to estimate a pooled result from the two trials reporting this outcome. People receiving anti-VEGF were less likely to have vitreous or pre-retinal haemorrhage at 12 months (RR 0.32, 95% CI 0.16 to 0.65; 3 RCTs, 342 participants, low quality evidence). No study reported on fluorescein leakage or quality of life.All of the nine trials of anti-VEGF before or during vitrectomy investigated bevacizumab; most studies investigated bevacizumab before vitrectomy, one study investigated bevacizumab during surgery.People treated with bevacizumab and vitrectomy were less likely to lose 3 or more lines of visual acuity at 12 months compared with people given vitrectomy alone but the effect was imprecise and compatible with no effect or being more likely to lose vision (RR 0.49, 95% CI 0.08 to 3.14; 3 RCTs, 94 participants, low quality evidence). People treated with bevacizumab were more likely to gain 3 or more lines of visual acuity (RR 1.62, 95% CI 1.20 to 2.17; 3 RCTs, 94 participants, low quality evidence). On average, people treated with bevacizumab had better visual acuity at 12 months compared with people not receiving bevacizumab but there was uncertainty in the estimate (the CIs included 0; i.e. were compatible with no effect, and there was considerable inconsistency between studies; MD -0.24 logMAR, 95% CI -0.50 to 0.01; 6 RCTs, 335 participants, I(2) = 67%; low quality evidence). People receiving bevacizumab were less likely to have vitreous or pre-retinal haemorrhage at 12 months (RR 0.30, 95% CI 0.18 to 0.52; 7 RCTs, 393 participants, low quality evidence). No study reported on quality of life.Reasons for downgrading the quality of the evidence included risk of bias in included studies, imprecision of the estimates, inconsistency of effect estimates and indirectness (few studies reported at 12 months).Adverse effects were rarely reported and there was no evidence for any increased risk with anti-VEGF but given the relatively few studies that reported these, and the low event rate, the power of the analysis to detect any differences was low.

AUTHORS' CONCLUSIONS

There was very low or low quality evidence from RCTs for the efficacy and safety of anti-VEGF agents when used to treat PDR over and above current standard treatments. However, the results suggest that anti-VEGFs can reduce the risk of intraocular bleeding in people with PDR. Further carefully designed clinical trials should be able to improve this evidence.

Bevacizumab modulates the process of fibrosis in vitro

BACKGROUND

Fibrosis is the most common side effect after anti-vascular epithelial growth factor (VEGF) therapy (intravitreal bevacizumab) for retinal or choroidal neovascularization. This study was to investigate the efficacy of bevacizumab on the expressions of fibrosis-related cytokines in human umbilical vein endothelial cells (HUVECs) in vitro.

METHODS

Cultured HUVECs were divided into groups of controls (group 1), hypoxia (group 2) and hypoxia combined with bevacizumab (group 3). No treatment was given in group 1. In group 2, cobalt(II) chloride (CoCl₂) (200 μm) was added to the medium. In group 3, in addition to CoCl₂, bevacizumab was mixed in the medium, with a final concentration of 0.25 mg/mL, roughly equal to the concentration used clinically. The expressions of connective tissue growth factor (CTGF), transforming growth factor-β₂ (TGF-β₂) and basic fibroblast growth factor-2 (bFGF-2) were evaluated by SYBR green real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay at 6 h, 12 h, 24 h and 48 h. Matrix metalloproteinases (MMP)-2 was detected by SYBR green real-time PCR and Western blotting at each time point.

RESULTS

Both messenger RNA and protein levels of CTGF, bFGF, TGF-β₂ and MMP-2 in group 2 were higher than group 1 (P < 0.05). In group 3, the expressions of CTGF, bFGF, TGF-β₂ and MMP-2 were upregulated compared with group 2 (P < 0.05).

CONCLUSIONS

Bevacizumab at clinical doses can exert pro-fibrotic effects on HUVECs by upregulating the expressions of CTGF, bFGF, TGF-β₂ and MMP-2. This may be involved in fibrosis after anti-VEGF therapy.

Toxic effects of extracellular histones and their neutralization by vitreous in retinal detachment

Histones are DNA-binding proteins and are involved in chromatin remodeling and regulation of gene expression. Histones can be released after tissue injuries, and the extracellular histones cause cellular damage and organ dysfunction. Regardless of their clinical significance, the role and relevance of histones in ocular diseases are unknown. We studied the role of histones in eyes with retinal detachment (RD). Vitreous samples were collected during vitrectomy, and the concentration of histone H3 was measured by enzyme-linked immunosorbent assay. The location of the histones and related molecules was examined in a rat RD model. The release of histones and their effects on rat retinal progenitor cells R28 and ARPE-19 were evaluated in vitro. In addition, the protective role of the vitreous body against histones was tested. The intravitreal concentration of histones was higher in eyes with RD (mean, 30.9 ± 9.8 ng/ml) than in control eyes (below the limit of detection, P<0.05). In the rat RD model, histone H3 was observed on the outer side of the detached retina and was associated with photoreceptor death. Histone H3 was released from cultured R28 by oxidative stress. Histones at a concentration 10 μg/ml induced the production of interleukin-8 in ARPE-19 cells (2.5-fold increase, P<0.05) that was mediated through the ERK1/2- and p38 MAPK-dependent pathways and Toll-like receptor 4. Histones were toxic to cells at concentrations of ≥ 20 μg/ml. Vitreous body or hyaluronan decreased toxicity of histones by inhibiting diffusion of histones. These results indicate that histones are released from retinas with RD and may modulate the subretinal microenvironment by functioning as damage-associated molecular pattern molecules, thereby inducing proinflammatory cytokines or cell toxicity. In addition, the important role of the vitreous body and hyaluronan in protecting the retina from these toxic effects is suggested.

Effects of intravitreal injection of bevacizumab on inflammatory cytokines in the vitreous with proliferative diabetic retinopathy

BACKGROUND

To investigate the effects of preoperative intravitreal injection of bevacizumab (IVB) on the levels of 27 inflammatory cytokines, including interleukins (ILs) and vascular endothelial growth factor.

METHODS

From among 200 patients who had proliferative diabetic retinopathy and underwent vitrectomy in our department from September 2009 to October 2010, 8 study subjects met the enrollment criteria in which both eyes at nearly equivalent stages underwent vitrectomy. The first vitrectomy for each patient was performed without IVB (control group), whereas the second vitrectomy on the contralateral eye was performed with IVB treatment (1.25 mg/0.05 mL) 3 days before surgery (IVB group). Undiluted vitreous fluid was collected at the start of each vitrectomy. A multiplex assay was used to simultaneously determine the levels of 27 inflammatory cytokines and growth factors.

RESULTS

Mean vascular endothelial growth factor levels were significantly lower in the IVB group (519.69 pg/mL) than in the control group (11,807.44 pg/mL) (P = 0.012, Wilcoxon signed rank test). Moreover, the mean levels (IVB/control, pg/mL) of IL-1RA (38.50/62.31, P = 0.036), IL-5 (27.75/34.00, P = 0.018), IL-10 (433.63/1,995.94, P = 0.012), IL-12 (246.69/1,033.69, P = 0.012), IL-13 (707.50/1,450.38, P = 0.012), and interferon γ (71.13/84.69, P = 0.036) were significantly lower in the IVB group. No other significant differences were observed in the levels of the other 20 cytokines and growth factors between the 2 groups.

CONCLUSION

Preoperative IVB reduced not only the intravitreal vascular endothelial growth factor level but also the intravitreal levels of other inflammatory cytokines, including IL-1RA, IL-5, IL-10, IL-12, IL-13, and interferon γ. These results indicate the interaction of some cytokines in the vitreous fluid of proliferative diabetic retinopathy patients and suggest the possibility that preoperative IVB may not only reduce vascular proliferation by its direct antivascular endothelial growth factor effect but also modulate the inflammatory response through putative cytokine networks. None of the other cytokines examined were elevated after IVB.

Altered vascular microenvironment by bevacizumab in diabetic fibrovascular membrane

PURPOSE

The purpose of this study was to evaluate the impact of intravitreal bevacizumab (IVB) on three cellular components (vascular endothelial cells, pericytes, and myofibroblasts) of the vascular microenvironment in fibrovascular membranes (FVMs) of patients with proliferative diabetic retinopathy.

METHODS

Immunohistological studies with antibodies of CD34, αSMA, and transforming growth factor-β were performed on 20 surgical specimens obtained during a pars plana vitrectomy from 8 IVB-treated eyes, whereas 12 remained untreated. Four different indexes of vascular phenotype (vascular area, vascular major axis, CD34 endothelial area, and blood vessel density) and αSMA expression in vascular and stromal components were quantitatively analyzed.

RESULTS

The intraluminal area of blood vessels, CD34 endothelial area, and the blood vessel density in IVB-treated FVMs were significantly less than in untreated FVMs. The number of CD34 blood vessels in IVB-treated FVMs was similar to that in untreated FVMs. Intravitreal bevacizumab could not affect vascular and stromal αSMA area significantly. However, the ratio of vascular αSMA area/CD34 area was significantly higher in IVB-treated FVMs than in untreated FVMs. Transforming growth factor-β expression could be observed in the IVB-treated FVM.

CONCLUSION

Intravitreal bevacizumab might primarily affect blood vessels, and the effects on pericytes and myofibroblasts might be secondary. Intravitreal bevacizumab treatment regulates vascular microenvironment by the contraction of blood vessels, the increasing pericyte ratio, and transforming growth factor-β expression in FVMs of patients with proliferative diabetic retinopathy.

Responsiveness of eyes with polypoidal choroidal vasculopathy with choroidal hyperpermeability to intravitreal ranibizumab

Background

To determine the role played by vascular endothelial growth factor (VEGF) in polypoidal choroidal vasculopathy (PCV) based on an interventional immunology theory.

Methods

Eyes with PCV were divided in a masked fashion into those with choroidal hyperpermeability (HP group) and those with normal choroidal permeability (NP group) based on the indocyanine green angiograms. The inter-rater agreement rate was evaluated using Fleiss’ kappa. Patients were treated by intravitreal ranibizumab (IVB). The central choroidal thickness and central foveal thickness (CFT) at the baseline and 7 days after the treatment were measured by optical coherence tomography.

Results

Among the 57 consecutive eyes diagnosed with PCV, 42 eyes of 42 patients met the inclusion criteria (21 eyes/HP group vs 21 eyes /NP group). Central choroidal thickness in HP group was significantly thicker than that in the NP group (P < .001, Mann–Whitney U test). The inter-rater agreement was high with a Fleiss’ kappa = 0.95, P < .0001. The percentage reduction in the CFT in HP group (14.0%) was significantly less than that in NP group (20.4%; P = .013, Mann–Whitney U test).

Conclusions

Eyes with PCV that are associated with choroidal hyper-permeability may not be strongly associated with VEGF-related pathology, and may not respond favorably to anti-VEGF monotherapy.

Angiofibrotic response to vascular endothelial growth factor inhibition in diabetic retinal detachment: report no. 1

OBJECTIVES To assess the effect of bevacizumab injection on connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF) in the ocular fluids of patients with diabetic traction retinal detachment, and to determine whether intraoperative and postoperative complications are decreased in eyes given adjunctive preoperative bevacizumab injection. METHODS Twenty eyes of 19 patients were randomized to receive intravitreal bevacizumab or sham injection 3 to 7 days before vitrectomy for severe proliferative diabetic retinopathy. We collected aqueous samples before injection and at the time of vitrectomy and extracted undiluted vitreous samples. RESULTS Five eyes had decreased vascularization of membranes from preinjection to the time of vitrectomy (all in the bevacizumab treatment arm). Median visual acuities were 20/400 in control eyes at baseline and postoperative month 3 (POM3) and 8/200 in the bevacizumab-treated group at baseline and 20/100 at POM3 (P= .30 between control and bevacizumab-treated groups at POM3). All retinas were attached at POM3. Vitreous levels of VEGF were significantly lower in the bevacizumab group than in the control group (P= .03). Vitreous levels of CTGF were slightly lower in the bevacizumab group compared with the control group, but this difference was not statistically significant (P= .38). Levels of CTGF in the aqueous were strongly correlated with CTGF levels in the vitreous of controls (Spearman correlation coefficient, 0.95 [P< .001]). CONCLUSIONS Intravitreal bevacizumab injection reduces vitreous levels of VEGF and produces a clinically observable alteration in diabetic fibrovascular membranes. Ocular fluid levels of CTGF are not significantly affected within the week after VEGF inhibition. Retinal reattachment rates and visual acuity are not significantly altered by preoperative intravitreal bevacizumab injection at POM3. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01270542.

Larger therapeutic window for steroid versus VEGF-A inhibitor in inflammatory angiogenesis: surprisingly similar impact on leukocyte infiltration

PURPOSE

The current treatments against inflammatory angiogenesis are steroids and anti-VEGF-A, such as dexamethasone and bevacizumab, respectively. However, the therapeutic windows for dexamethasone and bevacizumab against inflammatory angiogenesis are unknown.

METHODS

To investigate the therapeutic windows for dexamethasone and bevacizumab, we used the corneal pocket assay. IL-1β pellets were implanted in corneas of BALB/c mice that were then treated with dexamethasone or bevacizumab at different time points. Angiogenesis (area, number of vessels, and sprouting) was quantitated at various time points after implantation. Nuclear Factor-κB (NF-κB) signaling and leukocyte accumulation in inflammatory angiogenesis were examined by Western blotting, by immunohistochemistry, and in the authors' novel leukocyte transmigration assay.

RESULTS

Dexamethasone inhibited IL-1β-induced angiogenesis when treatment started 4 days after IL-1β implantation, while bevacizumab only inhibited angiogenesis by day 2 after implantation. Both bevacizumab and dexamethasone inhibited angiogenic sprouting. Interestingly, bevacizumab did not affect NF-κB activation, which is one of the main signaling targets for steroid action. The authors' new imaging approach revealed that bevacizumab and steroid treatment blocked leukocyte infiltration into implanted corneas.

CONCLUSIONS

VEGF-A inhibition affected angiogenic sprouting, while it was not effective against matured vessels. Both dexamethasone and bevacizumab inhibited leukocyte transmigration from angiogenic vessels; however, dexamethasone had a larger therapeutic window. These insights improve the treatment strategy in angiogenic disorders.

Role of intravitreal inflammatory cytokines and angiogenic factors in proliferative diabetic retinopathy

OBJECTIVE

Inflammatory reaction has been shown to involve the progress of type 2 (non-insulin-dependent) diabetes. We, therefore, examined the effects of inflammatory cytokines and angiogenic factors in the pathogenesis of proliferative diabetic retinopathy (PDR) in type 2 diabetes.

PATIENTS AND METHODS

Vitreous fluid samples were obtained by vitrectomy from 62 eyes of PDR patients with type 2 diabetes and from 20 eyes of age-matched non-diabetic patients. The concentrations of interleukin 1 beta (IL1B), IL6, IL8, IL10, chemokine (C-C motif) ligand 2 (CCL2), endothelin 1 (EDN1), vascular endothelial growth factor (VEGF), and tumor necrosis factor (TNF) in the vitreous samples were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The concentrations of LI1B, IL6, IL8, CCL2, EDN1, VEGF, and TNF in the vitreous samples were considerably higher in PDR patients in comparison with the controls. However, the level of IL10 in PDR patients was similar to that obtained in the controls. Analysis of the correlations of the studied factors revealed the correlation of VEGF and IL6, VEGF and EDN1, IL8 and CCL2, and EDN1 and TNF in PDR patients. In addition, a significant positive correlation was observed between vitreous TNF as well as EDN1 and serum HbA(1)c levels in PDR patients.

CONCLUSIONS

The inflammatory cytokines and angiogenic factors IL1B, IL6, IL8, CCL2, EDN1, VEGF, and TNF are increased in the vitreous of PDR patients without an increase in IL-10. These results add support to the role of inflammatory cytokines and angiogenic factors in the genesis of PDR. Understanding the implication of these cytokines may provide diagnostic tools and therapeutic targets for treatment and prevention of PDR.

Vascular endothelial growth factor in plasma and vitreous fluid of patients with proliferative diabetic retinopathy patients after intravitreal injection of bevacizumab

PURPOSE

To investigate plasma and vitreous vascular endothelial growth factor (VEGF) levels after intravitreal bevacizumab (IVB) injection into eyes with proliferative diabetic retinopathy (PDR).

DESIGN

Retrospective, interventional, nonrandomized, comparative study.

METHODS

Fifty-six eyes of 56 patients with PDR and 13 eyes of 13 patients with nondiabetic ocular diseases were enrolled. Analysis included evaluation of basic clinical conditions and measurement of vitreous and plasma VEGF concentrations using enzyme-linked immunosorbent assays.

RESULTS

PDR eyes without IVB had the highest vitreous VEGF levels; the levels were significant compared with those in the recent IVB group (previous injection within 1 week), the prolonged IVB group (injection more than 1 week previously), and the nondiabetic control group (P = .001, P = .035, P < .001, respectively). The vitreous VEGF level in the recent IVB group was higher than that in prolonged IVB group (P = .035). PDR eyes without IVB had the highest plasma VEGF level, and the level was significant compared with those in the recent IVB group, the prolonged IVB group, and the nondiabetic control group (P < .001, P = .003, P < .001, respectively). The plasma VEGF level in the recent IVB group was lower than that in the prolonged IVB group (P = .003). The vitreous VEGF level was associated significantly with the plasma VEGF level (P = .002).

CONCLUSIONS

Vitreous and plasma VEGF levels were increased markedly in patients with PDR. VEGF concentrations in vitreous and plasma were decreased significantly after IVB into PDR eyes, and the effect lasted from 4.4 ± 2.2 days to 34.8 ± 33.7 days after injection.

Treatment of proliferative diabetic retinopathy with anti-VEGF agents

Proliferative diabetic retinopathy (PDR) is the most common cause of severe visual loss in people with diabetes. Although panretinal photocoagulation (PRP) remains the gold standard of care to date, several combinations of new treatment modalities have emerged. These approaches can be used to increase the extent of treatment, expedite the effect of laser treatment and provide alternate measures when laser delivery is difficult or impossible, especially in patients with vitreous haemorrhage. Currently, most of the research in this field is focussed on inhibitors of vascular endothelial growth factor (VEGF), referred to herein as anti-VEGF agents. Although limited by their short-lived effects and a lack of established protocols, anti-VEGF agents are widely available, especially for the treatment of aggressive PDR. This review analyses published studies using anti-VEGF agents alone or as an adjunct to other therapies in the treatment of PDR.

SCORE Study report #11: incidences of neovascular events in eyes with retinal vein occlusion

PURPOSE

To investigate in The Standard Care versus COrticosteroid for REtinal Vein Occlusion (SCORE) Study: (1) incidences of neovascular events and retinal capillary nonperfusion (abbreviated as "nonperfusion"), and their relationship with treatment groups; (2) neovascular incidences by nonperfusion status; and (3) pertinent baseline factors for their potential risk for neovascular events.

DESIGN

Two multicenter, randomized clinical trials, 1 evaluating participants with central retinal vein occlusion (CRVO) and the other evaluating participants with branch retinal vein occlusion (BRVO).

PARTICIPANTS

At 36 months, data were available for 81 participants with CRVO and 128 with BRVO.

INTERVENTION

Standard care (observation or grid photocoagulation) versus 1 or 4 mg intravitreal triamcinolone.

MAIN OUTCOME MEASURES

Neovascularization of the iris (NVI), neovascular glaucoma (NVG), disc or retinal neovascularization (NVD/NVE), preretinal or vitreous hemorrhage (PRH/VH), and nonperfusion.

RESULTS

The cumulative 36-month incidences for CRVO and BRVO eyes, respectively, were 8.5% and 2.4% for NVI or NVG; 8.8% and 7.6% for NVD/NVE or PRH/VH. There were no differences in incidences of neovascular events or risk of nonperfusion when comparing the 3 treatment groups within diseases. For CRVO at 36 months, 16.6% of eyes with ≥5.5 disc areas of nonperfusion versus 4.0% of eyes with <5.5 disc areas of nonperfusion developed NVG (P = 0.0003); for BRVO at 36 months, 14.6% versus 2.4% developed NVD/NVE (P<0.0001). Similar results were noted for most other neovascular events. Nonperfusion was the only significant baseline factor for neovascularization in BRVO, with the risk of a neovascular event increasing with greater disc areas of nonperfusion, and the highest risk noted at ≥5.5 disc areas.

CONCLUSIONS

In the SCORE Study, triamcinolone treatment was not associated with lower incidences of neovascular events or nonperfusion status compared with observation or grid photocoagulation. Cumulative 36-month incidences for most neovascular events were significantly higher for nonperfused than perfused eyes. Greater baseline disc areas of nonperfusion increased the risk of neovascularization in BRVO but not CRVO eyes, possibly owing to obscuration of retinal capillary details caused by dense hemorrhage at baseline for CRVO eyes. Increased risk of neovascularization was noted below the historical threshold of 10 disc areas of nonperfusion for retinal vein occlusion.

Effect of intravitreal bevacizumab on vascular endothelial growth factor expression in patients with proliferative diabetic retinopathy

PURPOSE

To investigate the effect of bevacizumab (Avastin; Genentech, San Francisco, CA, USA) on vascular endothelial growth factor (VEGF) expression and inflammation in fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR).

MATERIALS AND METHODS

Fibrovascular membranes from 19 eyes of 18 patients with PDR were studied using immunohistochemistry and analyzed in the following 3 groups; group 1: 4 inactive PDR eyes, group 2: 10 active PDR eyes treated preoperatively with adjunctive intravitreal bevacizumab, group 3: five active PDR eyes not treated preoperatively with bevacizumab. Immunohistochemical staining for VEGF, CD31 and CD68 were done.

RESULTS

The immunoreactivity to VEGF and CD 31-positive blood vessels was significantly higher in membranes from group 3 than group 1 (p = 0.007 for VEGF, 0.013 for CD 31-positive vessels). Intravitreal bevacizumab caused a reduction in VEGF expression and vascular densities in 4 out of 10 (40%) excised membranes from eyes with PDR. However, six membranes (60%) in group 2 still demonstrated relatively strong VEGF expression and high vascular density. Infiltration of macrophages was observed in 16 out of the 19 membranes, and the density of macrophages was increased in group 2 compared with group 1 (p = 0.043).

CONCLUSION

Intravitreal bevacizumab injections caused some reduction in VEGF expression and vascular densities in a limited number of active PDR patients. A single intravitreal bevacizumab injection may not be enough to induce complete blockage of VEGF and pathologic neovascularization in active PDR patients. Repeated injections, panretinal photocoagulation and/or PPV may be necessary following intravitreal bevacizumab to reinforce the anti-VEGF effect of the drug.

Intravitreal Injection of Bevacizumab Induces Inflammatory Alterations in a Uveitis Experimental Model

Purpose

Bevacizumab is currently used as an intravitreal agent in the treatment of inflammatory-associated eye diseases. The aim of the current study is to explore the effects of the intravitreal injection of bevacizumab on aqueous humour cytokines and chemokines in an experimental uveitis model.

Methods

Endotoxin-induced uveitis was induced in rats by footpad injections. Bevacizumab was administered by intravitreal injection (75 μg in 3–μL samples) and different chemokine and cytokine proteins were quantified in aqueous humor.

Results

Intravitreal administration of bevacizumab led to a several-fold increase of RANTES, MCP-1, and IFN-γ concentrations in aqueous humor of endotoxin-treated rats.

Conclusions

Given the exacerbating effect of bevacizumab on inflammation agents and considering the increasing use of bevacizumab as an off-label intravitreal agent, care should be taken if an underlying inflammatory disease is present.

Stromal cell-derived factor-1 is essential for photoreceptor cell protection in retinal detachment

Stromal cell-derived factor-1 (SDF-1) causes chemotaxis of CXCR4-expressing bone marrow-derived cells. SDF-1 is involved in the pathogenesis of various vascular diseases, including those of the eye. However, the role of SDF-1 in neuronal diseases is not completely understood. Here, we show higher SDF-1 levels in the vitreous humor of patients with retinal detachment (RD) compared with normal patients. SDF-1 correlated positively with the duration as well as the extent of RD. Furthermore, SDF-1 correlated significantly with levels of interleukin-6 and interleukin-8, but not with vascular endothelial growth factor. Western blot analysis results showed significant SDF-1 up-regulation in detached rat retinas compared with normal animals. Immunohistochemistry data showed that SDF-1 was co-localized with the glial cells of the detached retina. SDF-1 blockade with a neutralizing antibody increased photoreceptor cell loss and macrophage accumulation in the subretinal space. The retinal precursor cell line R28 expressed CXCR4. SDF-1 rescued serum starvation-induced apoptosis in R28 cells and enhanced their ability to participate in wound closure in a scratch assay. Our results indicate a surprising, protective role for SDF-1 in RD. This effect may be mediated directly or indirectly through other cell types.