Peripheral blood metabolic and inflammatory factors as biomarkers to ocular findings in diabetic macular edema

Quantification of foveal avascular zone area and macular vascular density changes in papilledema by swept-source optical coherence tomography angiography

This work provide objective measures of foveal avascular zone area and macular vascular density by swept-source optical coherence tomography angiography during the follow-up of a patient with papilledema due to secondary intracranial hypertension.

Evaluating peripheral blood inflammatory and metabolic biomarkers as predictors in diabetic retinopathy and diabetic macular edema

Purpose

To determine the correlation between serum inflammatory and metabolic biomarkers of patients with diabetic retinopathy (DR) and diabetic macular edema (DME).

Methods

Serum samples were obtained from 100 diabetic patients. Patients were divided into three groups: group 1 (patients with no DR, n = 27), group 2 (DR with DME, n = 34), and group 3 (DR without DME, n = 39). Serum concentrations of C-reactive protein (CRP) and interleukin-6 (IL-6) were measured by quantitative turbidimetric immunoassay and sandwich chemiluminescence immunoassay, respectively. Metabolic parameters such as glycated hemoglobin (HbA1c), total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglyceride (TG), serum creatinine, and blood urea were determined by automated analyzer om-360 after standardization.

Results

The levels of IL-6 and CRP differed significantly in patients with DR and without DR (P < 0.001 and P = 0.045, respectively). We also found a positive correlation between IL-6 and CRP with the severity of DR. When DR patients with DME were compared to patients without DME, only IL-6 was observed to be significantly elevated (P < 0.001). None of the metabolic markers correlated significantly with DR and DME.

Conclusion

Significantly raised levels of serum inflammatory biomarkers can be used to elucidate the significant role of inflammation in the pathogenesis of DR. Therefore, circulating biomarkers can serve as diagnostic and therapeutic predictors for monitoring the onset and progression of DR and DME.

Healthy lifestyle behaviors, mediating biomarkers, and risk of microvascular complications among individuals with type 2 diabetes: A cohort study

BACKGROUND

The influence of overall lifestyle behaviors on diabetic microvascular complications remains unknown. In addition, the potential mediating biomarkers underlying the association is unclear. This study aimed to examine the associations of the combined lifestyle factors with risks of total and individual microvascular complications among patients with type 2 diabetes (T2D) and to explore the potential mediation effects of metabolic biomarkers.

METHODS AND FINDINGS

This retrospective cohort study included 15,104 patients with T2D free of macro- and microvascular complications at baseline (2006 to 2010) from the UK Biobank. Healthy lifestyle behaviors included noncurrent smoking, recommended waist circumference, regular physical activity, healthy diet, and moderate alcohol drinking. Outcomes were ascertained using electronic health records. Over a median of 8.1 years of follow-up, 1,296 cases of the composite microvascular complications occurred, including 558 diabetic retinopathy, 625 diabetic kidney disease, and 315 diabetic neuropathy, with some patients having 2 or 3 microvascular complications simultaneously. After multivariable adjustment for sociodemographic characteristics, history of hypertension, glycemic control, and medication histories, the hazard ratios (95% confidence intervals (CIs)) for the participants adhering 4 to 5 low-risk lifestyle behaviors versus 0 to 1 were 0.65 (0.46, 0.91) for diabetic retinopathy, 0.43 (0.30, 0.61) for diabetic kidney disease, 0.46 (0.29, 0.74) for diabetic neuropathy, and 0.54 (0.43, 0.68) for the composite outcome (all Ps-trend ≤0.01). Further, the population-attributable fraction (95% CIs) of diabetic microvascular complications for poor adherence to the overall healthy lifestyle (<4 low-risk factors) ranged from 25.3% (10.0%, 39.4%) to 39.0% (17.7%, 56.8%). In addition, albumin, HDL-C, triglycerides, apolipoprotein A, C-reactive protein, and HbA1c collectively explained 23.20% (12.70%, 38.50%) of the associations between overall lifestyle behaviors and total diabetic microvascular complications. The key limitation of the current analysis was the potential underreporting of microvascular complications because the cases were identified via electronic health records.

CONCLUSIONS

Adherence to overall healthy lifestyle behaviors was associated with a significantly lower risk of microvascular complications in patients with T2D, and the favorable associations were partially mediated through improving biomarkers of glycemic control, systemic inflammation, liver function, and lipid profile.

Diabetic Patients With Rosacea Increase the Risks of Diabetic Macular Edema, Dry Eye Disease, Glaucoma, and Cataract

PURPOSE

Inflammation plays a role in diabetic eye diseases, but the association between rosacea and eye diseases in patients with diabetes remains unknown.

DESIGN

This retrospective cohort study used claims data from the National Health Insurance Research Database in Taiwan to investigate the association between rosacea and eye diseases in patients with diabetes.

MATERIALS AND METHODS

Taiwanese patients diagnosed as having diabetes mellitus between January 1, 1997, and December 31, 2013, and using any hypoglycemic agents were included and divided into rosacea and nonrosacea groups. After applying 1:20 sex and age matching and exclusion criteria, 1:4 propensity score matching (PSM) was conducted to balance the covariate distribution between the groups. The risk of time-to-event outcome between rosacea and nonrosacea groups in the PSM cohort was compared using the Fine and Gray subdistribution hazard model.

RESULTS

A total of 4096 patients with rosacea and 16,384 patients without rosacea were included in the analysis. During a mean follow-up period of 5 years, diabetic patients with rosacea had significantly higher risks of diabetic macular edema [subdistribution hazard ratio (SHR): 1.31, 95% confidence interval (CI): 1.05-1.63], glaucoma with medical treatment (SHR: 1.11, 95% CI: 1.01-1.21), dry eye disease (SHR: 1.55, 95% CI: 1.38-1.75), and cataract surgery (SHR: 1.13, 95% CI: 1.02-1.25) compared with diabetic patients without rosacea. A cumulative incidence analysis performed up to 14 years after the index date revealed that the risks of developing ocular diseases consistently increased over time. No significant differences in diabetic retinopathy, age-related macular degeneration, retinal vascular occlusion, ischemic optic neuropathy, optic neuritis, uveitis, or retinal detachment were identified according to rosacea diagnosis. However, we observed significant associations between rosacea and psoriasis, irritable bowel syndrome, anxiety, and major depressive disorder among patients with diabetes.

CONCLUSIONS

Rosacea is associated with diabetic macular edema, glaucoma, dry eye disease, and cataract development in diabetic patients, as well as increased risks of psoriasis, irritable bowel syndrome, anxiety, and depression in diabetic patients.

MicroRNA-150 (miR-150) and Diabetic Retinopathy: Is miR-150 Only a Biomarker or Does It Contribute to Disease Progression?

Diabetic retinopathy (DR) is a chronic disease associated with diabetes mellitus and is a leading cause of visual impairment among the working population in the US. Clinically, DR has been diagnosed and treated as a vascular complication, but it adversely impacts both neural retina and retinal vasculature. Degeneration of retinal neurons and microvasculature manifests in the diabetic retina and early stages of DR. Retinal photoreceptors undergo apoptosis shortly after the onset of diabetes, which contributes to the retinal dysfunction and microvascular complications leading to vision impairment. Chronic inflammation is a hallmark of diabetes and a contributor to cell apoptosis, and retinal photoreceptors are a major source of intraocular inflammation that contributes to vascular abnormalities in diabetes. As the levels of microRNAs (miRs) are changed in the plasma and vitreous of diabetic patients, miRs have been suggested as biomarkers to determine the progression of diabetic ocular diseases, including DR. However, few miRs have been thoroughly investigated as contributors to the pathogenesis of DR. Among these miRs, miR-150 is downregulated in diabetic patients and is an endogenous suppressor of inflammation, apoptosis, and pathological angiogenesis. In this review, how miR-150 and its downstream targets contribute to diabetes-associated retinal degeneration and pathological angiogenesis in DR are discussed. Currently, there is no effective treatment to stop or reverse diabetes-caused neural and vascular degeneration in the retina. Understanding the molecular mechanism of the pathogenesis of DR may shed light for the future development of more effective treatments for DR and other diabetes-associated ocular diseases.

Exploring the angiographic-biologic phenotype in the IMAGINE study: quantitative UWFA and cytokine expression

BACKGROUND

This study investigates the association of intraocular cytokine expression and ultrawide-field fluorescein angiography (UWFA) quantitative imaging biomarkers and their association with angiographical feature response after antivascular endothelial growth factor (VEGF) therapy in diabetic macular oedema (DME).

METHODS

The IMAGINE DME study is a post hoc imaging biomarker and intraocular cytokine assessment from the DAVE study, a prospective DME clinical trial that included aqueous humour sampling and UWFA imaging. Fifty-four cytokines associated with inflammation and angiogenesis were evaluated through multiplex arrays. UWFA parameters were assessed using an automated feature analysis platform to determine ischaemic and leakage indices and microaneurysm (MA) count. Eyes were classified into UWFA responder or non-responder groups based on longitudinal quantitative UWFA parameter improvement. Cytokine expression was correlated with UWFA metrics and evaluated in the context of therapeutic response.

RESULTS

Twenty-one eyes were included with a mean age of 55±10 years. Increased panretinal leakage index correlated with VEGF (r=0.70, p=0.0005), angiopoietin-like 4 (r=0.77, p=4.6E-5) and interleukin (IL)-6 (r=0.64, p=0.002). Panretinal ischaemic index was associated with tissue inhibitor of metalloproteinases 1 (TIMP-1, r=0.49, p=0.03) and peripheral ischaemia correlated with VEGF (r=0.45, p=0.05). MA count correlated with increased monocyte chemotactic protein-4 (MCP-4, r=0.60, p=0.004) and platelet and endothelial cell adhesion molecule 1 (PECAM-1, r=0.58, p=0.005). Longitudinal MA reduction was associated with decreased baseline VEGF and urokinase receptor (uPAR) (p<0.05). High baseline VEGF and IL-6 were associated with dramatic reduction in macular leakage (p<0.05).

CONCLUSIONS

Baseline and longitudinal quantitative UWFA imaging parameters correlated with multiple aqueous humour cytokine concentrations, including VEGF and IL-6. Further research is needed to assess the possible implications of using these findings for evaluating treatment response.

Aqueous Humor Factors' Predictive Effects in Treating Refractor Macular Edema: An Overview

The refractory macular edema (RME) seriously affects the patient's vision due to its repetition and ineffective drug response. RME is mainly related to the inflammatory pathway and angiogenesis pathway. At present, microglia activation and angiogenesis have also been widely focused on. With the promotion of the concept of precision diagnosis and treatment, intraocular fluid is becoming a popular evidence-based method. The detection and evaluation of aqueous humor factors can provide more accurate evidences and guidance for the treatment of RME. The purpose of this article is to review the treatment prediction and assessment progress of aqueous humor cytokines for the RME, giving evidence to provide a basis for expanding the diagnosis and treatment ideas of RME and guiding the development of personalized medical treatment.

Prediction of anti-VEGF efficacy in diabetic macular oedema using intraocular cytokines and macular optical coherence tomography

PURPOSE

In eyes with diabetic macular oedema (DME), aqueous humour (AH) cytokine levels before and after anti-vascular endothelial growth factor (VEGF) treatment were compared and correlated with optical coherence tomography structural parameters.

METHODS

This prospective study included 56 control patients with cataracts and 83 patients with DME manifesting as diffuse retinal thickening (DRT), cystoid macular oedema and serous retinal detachment (SRD). AH samples were obtained before intravitreal injection of anti-VEGF or cataract surgery. VEGF, interleukin (IL)-6, IL-8, IL-10, interferon-inducible protein 10 (IP-10) and monocyte chemotactic protein 1 (MCP-1) levels were measured by multiplex bead assay. AH cytokine levels, central macular thickness (CMT), number of hyper-reflective foci (HF), continuity of external limiting membrane and ellipsoid zone (EZ) and best-corrected visual acuity were evaluated.

RESULTS

In SRD, IL-6 and MCP-1 levels and HF were increased (all p < 0.05) compared to DRT. At baseline, the number of HF was correlated with VEGF, IL-6, IL-8, IP-10 and MCP-1 (all p < 0.05). Eyes sensitive to anti-VEGF treatment had high baseline levels of VEGF, MCP-1, HF and many EZ disruptions (all p < 0.05). DME patients with normal VEGF levels but with high levels of IL-8, IP-10 and MCP-1 (all p < 0.05) had little change in CMT after anti-VEGF treatment (p = 0.678).

CONCLUSIONS

AH concentrations of some inflammatory cytokines in DME were differentially expressed among the three DME morphologies. HF was associated with VEGF and other inflammatory cytokine levels. Multiple HF at baseline predicted a significant decrease in CMT, and eyes with normal VEGF but increased inflammatory cytokines may be insensitive to anti-VEGF treatment.

Inflammatory mediators in diabetic retinopathy: Deriving clinicopathological correlations for potential targeted therapy

The role of inflammation in diabetic retinopathy (DR) is well-established and dysregulation of a large number of inflammatory mediators is known. These include cytokines, chemokines, growth factors, mediators of proteogenesis, and pro-apoptotic molecules. This para-inflammation as a response is not directed to a particular pathogen or antigen but is rather directed toward the by-products of the diabetic milieu. The inflammatory mediators take part in cascades that result in cellular level responses like neurodegeneration, pericyte loss, leakage, capillary drop out, neovascularization, etc. There are multiple overlaps between the inflammatory pathways occurring within the diabetic retina due to a large number of mediators, their varied sources, and cross-interactions. This makes understanding the role of inflammation in clinical manifestations of DR difficult. Currently, mediator-based therapy for DR is being evaluated for interventions that target a specific step of the inflammatory cascade. We reviewed the role of inflammation in DR and derived a simplified clinicopathological correlation between the sources and stimuli of inflammation, the inflammatory mediators and pathways, and the clinical manifestations of DR. By doing so, we deliberate mediator-specific therapy for DR. The cross-interactions between inflammatory mediators and the molecular cycles influencing the inflammatory cascades are crucial challenges to such an approach. Future research should be directed to assess the feasibility of the pathology-based therapy for DR.

Temporal variation of optical coherence tomography biomarkers as predictors of anti-VEGF treatment outcomes in diabetic macular edema

PURPOSE

To report a longitudinal analysis of specific optical coherence tomography (OCT) features in eyes with diabetic macular edema (DME) treated with anti-VEGF.

METHODS

A total of 133 eyes of 103 consecutive patients with center-involving DME were included in the study. The eyes were treated between August 2008 and April 2019 with three monthly intravitreal anti-VEGF injections, either with or without prompt or deferred laser, followed by pro re nata (PRN) re-treatment. The following OCT biomarkers were evaluated: subfoveal neuroretinal detachment (SND) (defined as present (SND+) or absent (SND-)), hyperreflective retinal foci (HRF) number (defined as: absent/few(HRF-) or moderate/many (HRF+)), external limiting membrane (ELM) integrity, central macular thickness (CMT), and central retinal thickness (CRT). Changes in SND status and in the number of HRF were evaluated at each DME recurrence throughout the follow-up(FU) period. Mutual correlation among OCT biomarkers and their relationship with visual and anatomic outcomes were assessed both at baseline and over the FU period.

RESULTS

The mean FU was 71.2 months (SD 28.4; min. 12-max. 111). At baseline, the prevalence of SRD+ was 27.8% and a high number of HRF were detected in 41.4% of the eyes. A significant reduction in the number of HRF, CMT, CRT, and in the prevalence of SND was recorded in the post-loading phase (p-value <0.0001). In DME recurrences, the presence of SND+ and HRF+ was significantly more frequent in eyes with baseline SND+ and HRF+ compared to eyes presenting baseline SND- and HRF- (p-value <0.0001). No role of SND (p-value: 0.926) and HRF (p-value: 0.281) as baseline predictors of visual and anatomic outcomes was demonstrated, while a worse visual outcome was significantly correlated with a higher incidence of relapsing SND+ (p-value <0.0001) and HRF+ (p-value <0.0028) throughout the FU period.

CONCLUSION

In this study, SND and HRF were frequently present in DME recurrences with the same pattern exhibited at baseline, suggesting that these OCT biomarkers may characterize a specific pattern of DME that repeats over time. Moreover, the results suggested that the persistence and recurrence of SND and HRF may account for a decrease in visual function more than the baseline prevalence of these biomarkers. Further studies are required to confirm these findings.

Intraocular fluid biomarkers (liquid biopsy) in human diabetic retinopathy

Purpose

This article aims to review the impact of detecting and quantifying intraocular biomarkers (liquid biopsy) in both aqueous and vitreous humor in eyes of people affected by diabetes mellitus.

Methods

This is a detailed review about aqueous and/or vitreous humor sampling in human diabetic eyes for proteomic and/or metabolomic analysis contributing to the understanding of the pathophysiology and treatment effects of diabetic retinopathy.

Results

Aqueous and vitreous humor molecular biomarkers proved to be directly correlated to each other and valuable to study retinal conditions. Moreover, proteomic and metabolomic analysis showed that the biomarkers of neuroinflammation, neurodegeneration, and vasculopathy are detectable in intraocular fluids and that their concentration changes in different stages of disease, and in response to treatment of all diabetic retinopathy aspects, mainly diabetic macular edema and proliferative retinopathy.

Conclusions

Liquid biopsy offers the possibility to improve our knowledge of intraocular eye disease induced by diabetes mellitus. The exact quantification of intraocular biomarkers contributes to the precision medicine approach even in the diabetic retinopathy scenario. The diffusion of this approach should be encouraged to have quantifiable information directly from the human model, which may be coupled with imaging data.

Systemic contribution of inflammatory mediators to the severity of diabetic and uveitic macular edema

PURPOSE

To assess whether serum cytokine and growth factor levels are associated with diabetic macular edema (DME) and uveitic macular edema (UME) objective severity.

METHODS

Cross-sectional observational study of 81 patients (1 eye/patient) with DME (n=48) and UME (n=33). Macular edema (ME) was defined upon central macular thickness (CMT) ≥ 300 μm on spectral domain optical coherence tomography (OCT). Serum samples were obtained from peripheral blood and IL-1β, IL-6, IL-8, IL-10, MCP-1, TNF-α, and VEGF levels were determined by Luminex analysis. Main outcome measure was the correlation between mediators' levels and CMT and macular volume (MV) on OCT for ME cases.

RESULTS

In DME, IL-6 levels were found to significantly correlate with MV (r=0.324; p=0.028) whereas in UME, IL-8 was significantly associated with both CMT (r=0.401; p=0.021) and MV (r=0.391; p=0.024). IL-8 independently correlated with CMT (ß=177.2; p=0.033) and MV (ß=3.17; p=0.008) in UME multivariate model.

CONCLUSION

Peripheral blood IL-6 and IL-8 levels could play a role in the severity of DME and UME, respectively. IL-8 even seems to be independently associated with CMT and MV in UME cases. Such systemic implications could enforce DME and UME personalized diagnostic and therapeutic approaches.

Correlation between Imaging Morphological Findings and Laboratory Biomarkers in Patients with Diabetic Macular Edema

PURPOSE

To investigate the potential association between peripheral blood biomarkers and morphological characteristics of retinal imaging in patients with diabetic macular edema (DME).

METHODS

Participants in this cross-sectional study were 36 consecutive patients (36 eyes) with treatment-naïve DME, who underwent spectral domain-optical coherence tomography (SD-OCT), fundus photography, and fundus fluorescein angiography (FFA). In addition, peripheral blood samples were taken to evaluate full blood count and biochemical parameters. Correlation between imaging characteristics and laboratory parameters was examined.

RESULTS

Eyes with central subfield thickness greater than 405 μm presented significantly higher neutrophils/lymphocytes (p = 0.043) and higher lipoprotein (a) compared to eyes with CST < 405 μm (p = 0.003). Presence of hyperreflective foci on SD-OCT was associated with significantly higher white blood cell count (p = 0.028). Ellipsoid zone disruption was associated with significantly lower hematocrit (p = 0.012), hemoglobin (p = 0.009), and red blood cell count (p = 0.026), as well as with higher lipoprotein (a) (p = 0.015). Macular ischemia on FFA was associated with significantly higher monocytes (p = 0.027) and monocytes/HDL (p = 0.019). No significant associations were found between laboratory parameters and subretinal fluid, intraretinal fluid, exudates, cysts, disorganization of inner retinal layers, epiretinal membrane, and external limiting membrane condition.

CONCLUSION

Specific imaging morphological characteristics were found to be associated with laboratory parameters in patients with DME. These findings may shed light on the pathophysiology of DME and its correlation with the development of specific clinical signs.

Distinct Serum and Vitreous Inflammation-Related Factor Profiles in Patients with Proliferative Vitreoretinopathy

INTRODUCTION

Proliferative vitreoretinopathy (PVR), which is regulated by growth factors and cytokines, is the leading cause of failure in vitreoretinal surgery. In this study, we aimed to investigate the role of the human serum and vitreous inflammation-related factors in the development of proliferative vitreoretinopathy (PVR).

METHODS

Blood and vitreous samples were obtained from patients undergoing pars plana vitrectomy. Inflammation-related factors were detected using an immunology multiplex assay on a Luminex® xMAP® platform. Patients with PVR and rhegmatogenous retinal detachment (RRD) were compared with macular hole (MH) or epiretinal membrane (ERM) patients without any other ocular or systemic disease.

RESULTS

Thirty-six serum samples and 34 vitreous samples were obtained. Thirty-one different growth factors and cytokines were detected in serum samples. However, none of the circulating growth factors and cytokines were found to be different from the controls. Ten different growth factors and cytokines were measured in the vitreous samples. The concentration levels of PDGF-AA, TGF-α, VEGF, IL-6, IL-8, and TNFβ were found to have significantly increased in the vitreous of PVR patients.

CONCLUSION

Our study found that none of the circulating inflammation-related factors were changed in PVR or RRD patients, indicating the absence of a system inflammatory biomarkers to predict the development of proliferative vitreoretinopathy. As a supplement to previous research, the concentrations of PDGF-AA, TGF-α, VEGF, IL-6, IL-8, and TNFβ were significantly upregulated in the vitreous of PVR patients. These factors should be considered for preventing PVR.

Anatomic Response to Intravitreal Dexamethasone Implant and Baseline Aqueous Humor Cytokine Levels in Diabetic Macular Edema

Purpose

To determine whether baseline cytokine aqueous humor (AH) levels are associated with diabetic macular edema (DME) anatomic response to dexamethasone intravitreal implant (DEX) injection.

Methods

This was a prospective cohort study of DME cases receiving DEX treatment. Seventy patients were recruited with center-involving DME with spectral-domain (SD) optical coherence tomography (OCT) detection of central macular thickness (CMT) ≥300 μm on macular cube 518 × 128-μm scan protocol (Cirrus SD-OCT). DEX injection and anterior chamber tap to obtain an AH sample were performed at the same time. Multiplex immunoassay was carried out for interleukin (IL)-1β, IL-3, IL-6, IL-8, IL-10; monocyte chemoattractant protein (MCP)-1; interferon gamma-induced protein (IP)-10; tumor necrosis factor (TNF)-α; and vascular endothelial growth factor (VEGF). A follow-up visit and OCT exam were undertaken 6 to 8 weeks afterward. The association between AH cytokine baseline levels and change in CMT and macular volume (MV) was defined as main outcome measure.

Results

Multivariate linear regression analysis showed a higher decrease in MV to be associated (Rs of 0.512) with four baseline items: higher MCP-1 (β = -0.4; P = 0.028), higher CMT (β = -0.003; P = 0.024), decreased visual acuity (β = -0.7; P = 0.040), and a diffuse retinal thickening (DRT) OCT pattern (β = -1.3; P < 0.001). Logistic regression found DRT also to be associated with higher odds of a good MV response (odds ratio, 31.96; 95% confidence interval [CI] 7.11-143.72; P < 0.001).

Conclusions

Even though visual acuity response and anatomic effect are not always correlated in DME, we found that baseline elevated MCP-1 AH levels and DRT pattern were biomarkers that predicted a future favorable anatomic response to DEX.

Characteristics of diabetic macular edema patients refractory to anti-VEGF treatments and a dexamethasone implant

Purpose

To determine the characteristics of diabetic macular edema (DME) patients refractory to intravitreal bevacizumab (IVB) treatments and an additional dexamethasone implant.

Methods

We classified 119 DME patients according to whether or not they are responsive to 3 consecutive monthly anti-VEGF treatments and/or an additional dexamethasone implant. We compared their concentrations of IL (interleukin)-1β, IL-8, IL-10, IL-17, placental growth factor (PlGF), and vascular endothelial growth factor (VEGF) in the aqueous humor as well as their optical coherence tomography (OCT) findings, and baseline characteristics. We used logistic regression analyses to identify preoperative factors related to refractoriness to treatments.

Results

Of 119 treatment-naïve DME patients, 50 (42.02%) patients showed responsiveness [central subfield thickness (CST) < 300μm] after 3 IVBs, and 59 (49.58%) patients showed responsiveness after an additional dexamethasone implant, but 10 (8.40%) patients showed CST 300 ≥ μm even after both treatments. Refractory DME patients showed significantly higher number of hyperreflective foci (HF) in the OCT and higher average level of aqueous IL-1β at baseline (p<0.001 and p = 0.042, respectively). In the logistic regression analysis, higher number of HF in the OCT was associated with the refractoriness to both treatments (odds ratio [OR]: 7.03, p = 0.007)

Conclusions

Higher number of HF in the OCT at the initial visit was associated with poor responses to IVBs and an additional dexamethasone implant.

Insights into the pathogenesis of cystoid macular edema: leukostasis and related cytokines

Cystoid macular edema (CME) is the abnormal collection of intraretinal fluid in the macular region, especially in the inner nuclear and outer plexiform layers. CME leads to severe visual impairment in patients with various retinal diseases, such as diabetic retinopathy, retinal vascular occlusion, choroidal neovascularization, and uveitis. Although various retinal conditions lead to CME, a shared pathogenesis of CME is involved in these diseases. Accordingly, the pathogenesis of CME based on vasogenic mechanisms is first discussed in this review, including vascular hyperpermeability, leukostasis, and inflammation. We then describe cytotoxic mechanisms based on retinal Müller cell dysfunction. This comprehensive review will provide an understanding of the pathogenesis of CME for potential therapeutic strategies.

Role of Inflammation in Classification of Diabetic Macular Edema by Optical Coherence Tomography

Diabetic macular edema (DME) is the abnormal accumulation of fluid in the subretinal or intraretinal spaces in the macula in patients with diabetic retinopathy and leads to severely impaired central vision. Technical developments in retinal imaging systems have led to many advances in the study of DME. In particular, optical coherence tomography (OCT) can provide longitudinal and microstructural analysis of the macula. A comprehensive review was provided regarding the role of inflammation using OCT-based classification of DME and current and ongoing therapeutic approaches. In this review, we first describe the pathogenesis of DME, then discuss the classification of DME based on OCT findings and the association of different types of DME with inflammation, and finally describe current and ongoing therapeutic approaches using OCT-based classification of DME. Inflammation has an important role in the pathogenesis of DME, but its role appears to differ among the DME phenotypes, as determined by OCT. It is important to determine how the different DME subtypes respond to intravitreal injections of steroids, antivascular endothelial growth factor agents, and other drugs to improve prognosis and responsiveness to treatment.

A Novel Biomarker in Diabetic Macular Edema with Serous Retinal Detachment: Serum Chitinase-3-Like Protein 1

PURPOSE

To determine whether serum chitinase-3-like protein 1 (CHI3L1) and interleukin-6 (IL-6) levels correlate with serous retinal detachment (SRD) in diabetic macular edema (DME) using spectral-domain optical coherence tomography (SD-OCT).

METHODS

In this cross-sectional case-control study, 394 patients (treatment-naive DME patients, n = 218; diabetic patients without DME, n = 96; nondiabetic controls, n = 80) were included in the study. Eyes were classified according to SD-OCT features of DME: SRD, cystoid macular edema (CMO), and diffuse retinal thickness (DRT). Serum concentrations of CHI3L1 and IL-6 were analyzed using enzyme-linked immunosorbent assay.

RESULTS

Serum CHI3L1 and IL-6 levels were significantly higher in DME with SRD compared to patients with CMO and DRT (p < 0.001 for all groups). Multivariate regression analysis showed that CHI3L1 and IL-6 had a stronger influence on the presence of SRD in DME (r = 1.162, p = 0.026, and r = 1.242, p = 0.016, respectively). Serum concentration of CHI3L1 was significantly correlated with that of IL-6 (r = 0.386, p = 0.0015).

CONCLUSIONS

Our data suggest that serum concentrations of CHI3L1 and IL-6 are involved in the process of SRD in DME. CHI3L1 can be investigated further as a new diagnostic biomarker for DME with SRD.

OCT Biomarkers as Functional Outcome Predictors in Diabetic Macular Edema Treated with Dexamethasone Implant

PURPOSE

Identification and characterization of patients with diabetic macular edema (DME) are important for individualizing treatment and optimizing outcome. We investigated OCT biomarkers for DME treated by intravitreal dexamethasone (DEX) implant.

DESIGN

Multicenter, retrospective, observational cohort study.

PARTICIPANTS

A total of 299 eyes from 284 patients treated with DEX implant for DME (naïve, n = 209; refractory, n = 90). Baseline best-corrected visual acuity (BCVA) was between 0.3 and 1.0 on a logarithm of minimum angle of resolution visual chart.

METHODS

The OCT scans previous to DEX implants were evaluated for submacular fluid, size and location of cystoid changes, inner segment-outer segment (IS-OS) continuity, quantity and location of hyperreflective foci (HRF), vitreomacular interface abnormalities, and epiretinal membrane. The BCVA and central macular thickness were recorded at baseline and at 1, 2, and 4 months after treatment with DEX implants. Correlations between OCT measures and visual outcome were analyzed using the generalized estimating equations procedure.

MAIN OUTCOME MEASURES

The correlation between spectral-domain (SD) OCT measures at baseline and BCVA response (mean change from baseline; categorized improvement [<5, 5-9, or ≥10; Early Treatment Diabetic Retinopathy Study letters] in BCVA) after treatment with a DEX implant.

RESULTS

The presence of subretinal fluid (odds ratio [OR], 1.98; 95% confidence interval [CI], 1.23-3.20; P = 0.01), absence of HRF (OR, 3.66; 95% CI, 1.40-9.62; P = 0.01), and integrity of the IS-OS layer (OR, 2.09; 95% CI, 1.30-3.37; P = 0.003) were all predictive of better visual outcome after treatment with DEX implants. Although eyes with naïve DME gained more vision than refractory eyes (P < 0.001), the predictive value of OCT findings did not differ according to this classification.

CONCLUSIONS

Spectral-domain OCT is useful in identifying various imaging findings in DME. Among eyes with DME, those with submacular fluid, no HRF, and a continuous IS-OS layer responded better to DEX implants than those without these features. These findings call for further study of combinations of OCT and metabolic biomarkers.