Differential association of elevated inflammatory cytokines with postoperative fibrous proliferation and neovascularization after unsuccessful vitrectomy in eyes with proliferative diabetic retinopathy

Heterotypic macrophages/microglia differentially contribute to retinal ischaemia and neovascularisation

AIMS/HYPOTHESIS

Diabetic retinopathy is characterised by neuroinflammation that drives neuronal and vascular degenerative pathology, which in many individuals can lead to retinal ischaemia and neovascularisation. Infiltrating macrophages and activated retina-resident microglia have been implicated in the progression of diabetic retinopathy, although the distinct roles of these immune cells remain ill-defined. Our aim was to clarify the distinct roles of macrophages/microglia in the pathogenesis of proliferative ischaemic retinopathies.

METHODS

Murine oxygen-induced retinopathy is commonly used as a model of ischaemia-induced proliferative diabetic retinopathy (PDR). We evaluated the phenotype macrophages/microglia by immunostaining, quantitative real-time RT-PCR (qRT-PCR), flow cytometry and scRNA-seq analysis. In clinical imaging studies of diabetic retinopathy, we used optical coherence tomography (OCT) and OCT angiography.

RESULTS

Immunostaining, qRT-PCR and flow cytometry showed expression levels of M1-like macrophages/microglia markers (CD80, CD68 and nitric oxide synthase 2) and M2-like macrophages/microglia markers (CD206, CD163 and macrophage scavenger receptor 1) were upregulated in areas of retinal ischaemia and around neo-vessels, respectively. scRNA-seq analysis of the ischaemic retina revealed distinct ischaemia-related clusters of macrophages/microglia that express M1 markers as well as C-C chemokine receptor 2. Inhibition of Rho-kinase (ROCK) suppressed CCL2 expression and reduced CCR2-positive M1-like macrophages/microglia in areas of ischaemia. Furthermore, the area of retinal ischaemia was reduced by suppressing blood macrophage infiltration not only by ROCK inhibitor and monocyte chemoattractant protein-1 antibody but also by GdCl3. Clinical imaging studies of diabetic retinopathy using OCT indicated potential involvement of macrophages/microglia represented by hyperreflective foci in areas of reduced perfusion.

CONCLUSIONS/INTERPRETATION

These results collectively indicated that heterotypic macrophages/microglia differentially contribute to retinal ischaemia and neovascularisation in retinal vascular diseases including diabetic retinopathy. This adds important new information that could provide a basis for a more targeted, cell-specific therapeutic approach to prevent progression to sight-threatening PDR.

Anti-vascular endothelial growth factors in combination with vitrectomy for complications of proliferative diabetic retinopathy

BACKGROUND

Vitrectomy is an established treatment for the complications of proliferative diabetic retinopathy (PDR). However, a number of complications can occur during and after vitrectomy for PDR. These include bleeding and the creation of retinal holes during surgery, and bleeding, retinal detachment and scar tissue on the retina after surgery. These complications can limit vision, require further surgery and delay recovery. The use of anti-vascular endothelial growth factor (anti-VEGF) agents injected into the eye before surgery has been proposed to reduce the occurrence of these complications. Anti-VEGF agents can reduce the amount and vascularity of abnormal new vessels associated with PDR, facilitating their dissection during surgery, reducing intra- and postoperative bleeding, and potentially improving outcomes.

OBJECTIVES

To assess the effects of perioperative anti-VEGF use on the outcomes of vitrectomy for the treatment of complications for proliferative diabetic retinopathy (PDR).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (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. The date of the search was 22 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that looked at the use of anti-VEGFs and the incidence of complications in people undergoing vitrectomy for PDR.   DATA COLLECTION AND ANALYSIS: Two review authors independently assessed and extracted the data. We used the standard methodological procedures expected by Cochrane. The critical outcomes of the review were the mean difference in best corrected visual acuity (BCVA) between study arms at six (± three) months after the primary vitrectomy, the incidence of early postoperative vitreous cavity haemorrhage (POVCH, within four weeks postoperatively), the incidence of late POVCH (occurring more than four weeks postoperatively), the incidence of revision surgery for POVCH within six months, the incidence of revision surgery for recurrent traction/macular pucker of any type and/or rhegmatogenous retinal detachment within six months and vision-related quality of life (VRQOL) measures. Important outcomes included the proportion of people with a visual acuity of counting fingers (1.8 logMAR or worse), the number of operative retinal breaks reported and the frequency of silicone oil tamponade required at time of surgery.

MAIN RESULTS

The current review includes 28 RCTs that looked at the pre- or intraoperative use of intravitreal anti-VEGFs to improve the outcomes of pars plana vitrectomy for complications of PDR. The studies were conducted in a variety of countries (11 from China, three from Iran, two from Italy, two from Mexico and the remaining studies from South Korea, the UK, Egypt, Brazil, Japan, Canada, the USA, Indonesia and Pakistan). The inclusion criteria for entry into the studies were the well-recognised complications of proliferative retinopathy: non-clearing vitreous haemorrhage, tractional retinal detachment involving the macula or combined tractional rhegmatogenous detachment. The included studies randomised a total of 1914 eyes.  We identified methodological issues in all of the included studies. Risk of bias was highest for masking of participants and investigators, and a number of studies were unclear when describing randomisation methods and sequence allocation. Participants receiving intravitreal anti-VEGF in addition to pars plana vitrectomy achieved better BCVA at six months compared to people undergoing vitrectomy alone (mean difference (MD) -0.25 logMAR, 95% confidence interval (CI) -0.39 to -0.11; 13 studies, 699 eyes; low-certainty evidence). Pre- or intraoperative anti-VEGF reduced the incidence of early POVCH (12% versus 31%, risk ratio (RR) 0.44, 95% CI 0.34 to 0.58; 14 studies, 1038 eyes; moderate-certainty evidence). Perioperative anti-VEGF use was also associated with a reduction in the incidence of late POVCH (10% versus 23%, RR 0.47, 95% CI 0.30 to 0.74; 11 studies, 579 eyes; high-certainty evidence). The need for revision surgery for POVCH occurred less frequently in the anti-VEGF group compared with control, but the confidence intervals were wide and compatible with no effect (4% versus 13%, RR 0.44, 95% CI 0.15 to 1.28; 4 studies 207 eyes; moderate-certainty evidence). Similar imprecisely measured effects were seen for revision surgery for rhegmatogenous retinal detachment (5% versus 11%, RR 0.50, 95% CI 0.15 to 1.66; 4 studies, 145 eyes; low-certainty evidence).  Anti-VEGFs reduce the incidence of intraoperative retinal breaks (12% versus 31%, RR 0.37, 95% CI 0.24 to 0.59; 12 studies, 915 eyes; high-certainty evidence) and the need for silicone oil (19% versus 41%, RR 0.46, 95% CI 0.27 to 0.80; 10 studies, 591 eyes; very low-certainty evidence). No data were available on quality of life outcomes or the proportion of participants with visual acuity of counting fingers or worse.

AUTHORS' CONCLUSIONS

The perioperative use of anti-VEGF reduces the risk of late POVCH, probably results in lower early POVCH risk and may improve visual outcomes. It also reduces the incidence of intraoperative retinal breaks. The evidence is very uncertain about its effect on the need for silicone oil tamponade. The reported complications from its use appear to be low. Agreement on variables included and outcome standardisation is required in trials studying vitrectomy for PDR.

23G Minimally Invasive Vitrectomy Combined with Glaucoma Drainage Valve Implantation and Phacoemulsification Cataract Extraction for Neovascular Glaucoma Secondary to Proliferative Diabetic Retinopathy with Vitreous Hemorrhage

Objective

To evaluate the clinical efficacy of the combined application of 23G minimally invasive vitrectomy, glaucoma drainage valve implantation, and phacoemulsification cataract extraction in the treatment of neovascular glaucoma (NVG) secondary to proliferative diabetic retinopathy (PDR) combined with vitreous hemorrhage (VH).

Methods

Eighty-three patients (91 eyes) with PDR diagnosed as NVG phase III complicated with VH from June 2018 to May 2020 were selected as the study subjects. The subjects were randomly divided into 3 groups: group A was treated with 23G minimally invasive vitrectomy combined with glaucoma drainage valve implantation; group B was given 23G minimally invasive vitrectomy combined with phacoemulsification cataract extraction; and group C was treated with 23G minimally invasive vitrectomy combined with glaucoma drainage valve implantation and phacoemulsification cataract extraction. The uncorrected visual acuity (UCVA), intraocular pressure (IOP), and iris neovascularization (INV) scores were recorded and compared among the 3 groups before and after operation, and then the postoperative pain relief and complications were observed.

Results

Through observation, there was no significant difference in the UCVA, IOP, and INV scores in the 3 groups before operation. After the operation, the UCVA, IOP, and INV scores of the 3 groups were significantly lower than those before operation. After operation, the UCVA of the 3 groups increased first and then decreased, and it improved most significantly in the 3rd month after operation and decreased in the 4th month after operation. There were significant differences in UCVA among the 3 groups at each time point after operation. From the 1st day to the 6th month after operation, the IOP of the 3 groups showed an upward trend, and there was no significant difference among the 3 groups in IOP at each time point after operation. At the 1st, 3rd, and 6th months after operation, the INV score of group A and group B was higher than that of group C. There was no significant difference in the INV score between group A and group B. The incidence of complications was not significantly different among the 3 groups.

Conclusion

23G minimally invasive vitrectomy, glaucoma drainage valve implantation, and phacoemulsification cataract extraction can effectively improve the UCVA, IOP, and INV scores of NVG secondary to PDR with VH, and the combined application of the 3 methods has better security.

Changes in Tears Monocyte Chemoattractant Protein-1 Level After External Dacryocystorhinostomy in Primary Acquired Nasolacrimal Duct Obstruction

BACKGROUND

The authors aimed to define tears monocyte chemoattractant protein-1 (MCP-1) changes after external dacryocystorhinostomy surgery.

MATERIALS AND METHODS

Tears samples were collected with a Schirmer strip and stored in Eppendorf tubes at -80°C. At the end of the study, the papers were cut into small pieces and incubated with phosphate-buffered saline solution. Monocyte chemoattractant protein-1 levels were determined by using an enzyme-linked immunosorbent assays kit.

RESULTS

The MCP-1 levels were 498.66±101.35, 576.40±149.78, 422.53±85.94, and 436.96±81.38 ng/L before surgery, in the first week, the first, and third months after surgery, respectively. Its level significantly increased in the first week compared with the preoperative level ( P <0.001). There was a prominent decrease in the postoperative first month ( P <0.001). In the third postoperative month, the mean MCP-1 level was not significantly increased compared with the postoperative first month ( P =0.196).

CONCLUSION

The tears MCP-1 level was significantly decreased after external dacryocystorhinostomy surgery.

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.

Clinical Features and Vitreous Biomarkers of Early-Onset Type 2 Diabetes Mellitus Complicated with Proliferative Diabetic Retinopathy

PURPOSE

To compare the clinical features and vitreous biomarkers of proliferative diabetic retinopathy (PDR) between patients with early-onset and late-onset type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

This case-control study analyzed the clinical data of 74 patients with PDR who underwent vitrectomy. The patients were divided into the early-onset (T2DM diagnosis age ≤ 40 years, n = 39) and late-onset (T2DM diagnosis age > 40 years, n = 35) groups. Thirty-six specimens were collected, and the liquid chip technology was used to detect the content of 27 types of cytokines in the vitreous. Differences in clinical features and cytokine levels between the two groups were evaluated. Bonferroni correction was applied for multiple comparisons.

RESULTS

Compared with the late-onset group, the levels of hemoglobin A1c (HbA1c) and total cholesterol were significantly higher in the early-onset group (P < 0.001 and P = 0.009, respectively). Patients with early-onset T2DM PDR had worse visual prognoses and a higher rate of postoperative recurrent vitreous hemorrhage. The results of cytokine detection showed that the levels of interleukin-4 (IL-4), IL-6, IL-8, IL-9, granulocyte colony-stimulating factor, interferon-γ, interferon-inducible 10 kDa, monocyte chemotactic protein 1, macrophage inflammatory protein (MIP)-1α, and MIP-1β in the early-onset group were significantly higher than those in the late-onset group (p < 0.0026). Age at diabetes diagnosis and HbA1c, IL-4, and regulated upon activation, normal T cell expressed and secreted levels were independent risk factors for visual acuity after undergoing vitrectomy.

CONCLUSION

Early-onset T2DM PDR patients had poor blood glucose and lipid metabolism, higher levels of inflammatory factors, and worse visual prognosis. Stricter metabolic management and earlier anti-inflammatory interventions may be required for patients with early-onset T2DM.

Isolated Central Epiretinal Membrane: A Rare Complication of Fovea-Sparing Internal Limiting Membrane Peeling Technique

Purpose

To report a rare complication presenting as an isolated central epiretinal membrane (ERM) related to fovea-sparing internal limiting membrane (ILM) peeling technique.

Methods

Five patients who received fovea-sparing ILM peeling were enrolled. Postoperatively, an isolated central ERM developed. Optical coherence tomography (OCT) was used to evaluate the serial anatomic change.

Results

Among the five included patients, one patient had high myopia with foveoschisis, two patients had vitreomacular traction, and two patients had proliferative diabetic retinopathy with tractional retinal detachment and a fovea cyst. With an average of 5.80 months, OCT showed the gradual development of the isolated central ERM with severe fovea distortion. Four patients received secondary revision surgery, with improvement of the fovea contour and visual acuity.

Conclusion

The fovea-sparing ILM peeling technique may cause a rare but serious complication as the isolated central ERM, which would cause significant fovea distortion as well as visual deterioration. Timely detection and intervention is recommended to prevent further visual loss. This trial is registered with NCT04445142.

Human amniotic membrane grafts for retinal breaks in diabetic tractional retinal detachment and combined tractional and rhegmatogenous retinal detachment

To describe the surgical outcomes of using human amniotic membrane (hAM) grafts in the management of retinal breaks in diabetic tractional detachment (TRD) and combined tractional and rhegmatogenous retinal detachment (CTRRD). A retrospective case series of 10 eyes with TRD or CTRRD receiving pars plana vitrectomy with hAM grafts implantation, compared with 13 controls receiving the same surgery without hAM grafts. Best-corrected visual acuity (BCVA) and re-detachment rate were compared between two groups. Postoperatively, all eyes in the hAM group had retina attachment without recurrence, while 9 eyes in the control group had retina re-detachment and required additional surgery (0% vs 69.2%, p = 0.003). The BCVA significantly improved in the hAM group (from 1.96 ± 0.95 to 1.44 ± 0.77 in log MAR, p = 0.03), but not improved in control group (p = 0.20). Postoperative optical coherence tomography of the eyes receiving hAM grafts demonstrated glial tissue regeneration and restoration of ellipsoid zone. In diabetic TRD or CTRRD, hAM grafts could be an effective method, with promising outcome. Compared to standard surgery, it could result in higher retina reattachment rate and significant visual improvement. Moreover, it may offer the adjunctive benefit in tissue regeneration and fasten ellipsoid zone restoration.

Aqueous humor monocyte chemoattractant protein-1 predicted long-term visual outcome of proliferative diabetic retinopathy undergone intravitreal injection of bevacizumab and vitrectomy

PURPOSE

We aim to investigate the risk factors associated with the prognosis of proliferative diabetic retinopathy (PDR) after a sequential treatment of intravitreal injection of bevacizumab (IVB) and pars plana vitrectomy (PPV).

METHODS

In this cohort study, 63 eyes from 55 patients (21 females) diagnosed with PDR, who needed PPV for non-clearing vitreous hemorrhage or fibrovascular membrane proliferation were enrolled. All the eyes underwent IVB followed by PPV. Anterior chamber tap was performed at the beginning of both procedures to evaluate the concentration of vascular endothelial growth factor (VEGF), interleukin (IL)-6, IL-8, and monocyte chemoattractant protein (MCP)-1.

RESULTS

Forty-seven patients (54 eyes) were followed over six months, averaging 12±5 (6-19) months. The concentration of VEGF significantly decreased after IVB (P<0.001), while other cytokines did not change significantly. The aqueous humor level of IL-8 after IVB (R = 0.378, P = 0.033), MCP-1 before (R = 0.368, P = 0.021) and after (R = 0.368, P = 0.038) IVB, and combined phacoemulsification (R = 0.293, P = 0.032) was correlated with the logMAR visual acuity at the last follow-up. Multivariate analysis showed that MCP-1 was the predictor for a worse visual outcome (B = 0.108, 95% CI 0.013-0.202; P = 0.027).

CONCLUSIONS

MCP-1 was a predictor for the unfavorable visual outcome of PDR after IVB pretreatment and PPV.

Cytokines associated with hemorrhage in proliferative diabetic retinopathy

PURPOSE

To investigate aqueous cytokine levels in association with hemorrhage in proliferative diabetic retinopathy (PDR) in patients with type 2 diabetes mellitus.

METHODS

Sixty-six eyes with treatment-naïve PDR, including 26 hemorrhagic and 40 nonhemorrhagic eyes were included in this institutional study. Aqueous humor levels of interleukin (IL)-1b, IL-6, IL-8, IL-10, monocyte chemoattractant protein (MCP)-1, tumor necrosis factor (TNF)-α, vascular endothelial growth factor (VEGF), and soluble VEGF receptor-1 were obtained by multiplex bead assay. Visual acuity and hemorrhage area measurements were obtained, and correlations between cytokine levels and hemorrhage were identified.

RESULTS

Levels of MCP-1, TNF-α, and VEGF were higher in hemorrhagic eyes (1506.77 vs. 2131.31 pg/mL, 0.43 vs. 0.63 pg/mL, and 103.96 vs. 206.96 pg/mL; P = 0.050, 0.022, and 0.027, respectively). The levels of IL-8, MCP-1, TNF-α, and VEGF showed positive correlation with visual acuity (P = 0.019, 0.015, 0.001, and 0.014, respectively). The hemorrhage area revealed positive correlation with TNF-α and VEGF levels (P = 0.001 and < 0.001, respectively).

CONCLUSION

The presence and amount of hemorrhage in PDR were associated not only with VEGF concentration, but also with the levels of certain inflammatory cytokines, suggesting a role of both VEGF and inflammation in hemorrhagic eyes.

The Effect of Internal Limiting Membrane Cleaning on Epiretinal Membrane Formation after Vitrectomy for Proliferative Diabetic Retinopathy

PURPOSE

We hypothesised that cleaning the internal limiting membrane (ILM) with a flexible nitinol loop following diabetic vitrectomy without peeling may reduce the common occurrence of postoperative epiretinal membrane (ERM) formation.

METHODS

Consecutive patients undergoing vitrectomy for proliferative diabetic retinopathy by one surgeon from 2015 to 2019 were studied and divided into 2 cohorts: the control group underwent standard surgery, and the ILM clean group underwent additional cleaning of the macular retina using a flexible nitinol loop after vitrectomy. Masked comparison of ERM on optical coherence tomography was performed at 3 months, and visual acuity (VA) was measured until 12 months postoperatively.

RESULTS

Baseline demographics, clinical features, and protein levels were similar between cohorts. The ILM clean group (n = 56) had fewer clinically significant ERM than the control group (n = 50; 4 vs. 20%; p = 0.01), and a significantly lower proportion of the ILM clean group required revision surgery (2 vs. 14%; p = 0.02). VA in the ILM clean group was significantly better than in the control group at 3 months (0.35 vs. 0.50 logMAR; p = 0.02) but not at 12 months (0.34 vs. 0.43 logMAR; p = 0.17).

CONCLUSION

ILM cleaning with a flexible nitinol loop following diabetic vitrectomy resulted in significant reduction in ERM formation and reduced necessity for revision surgery. There was significant improvement in VA at 3 months but not over a longer follow-up.

MicroRNA-199a-3p inhibits angiogenesis by targeting the VEGF/PI3K/AKT signalling pathway in an in vitro model of diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a major inducer of blindness and visual impairment. As a critical cause for DR, hyperglycaemia is able to trigger multiple biochemical alterations. MiRNAs, which contain various functions, can effectively regulate blood glucose levels. This research aims to confirm the roles of miRNA-199a-3p in the progression of angiogenesis in an in vitro model of DR.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was carried to determine the expression levels of miR-199a-3p and VEGF in both hRMECs and APRE-19 cells. The luciferase reporter assay was used to study the interaction between miR-199a-3p and VEGF. Western blot assay was conducted to examine the expression levels of VEGF and the PI3K/AKT signalling pathway. The cell proliferation capacity was detected via the CCK-8 test. The impact of miR-199a-3p on migration was determined using Transwell and wound healing assays. A Matrigel tube formation assay was employed to determine the vascular formation of hRMECs. Flow cytometry was used to determine cell apoptosis in the presence of LY294002 as a PI3K inhibitor.

RESULTS

Our results showed that high glucose (HG) decreased the relative expression level of miR-199a-3p but increased VEGF expression in hRMECs and APRE-19 cells. MiR-199a-3p inhibitor augmented cell growth, migration and angiogenesis of hRMECs. Moreover, upregulation of miR-199a-3p evidently alleviated the increases in cell proliferation, migration and angiogenesis caused by HG. In addition, the luciferase reporter assay indicated that miR-199a-3p directly targeted VEGF. The overexpression of miR-199a-3p obviously restrained the HG-stimulated PI3K/AKT signalling pathway and angiogenesis, which could be further inhibited by LY294002. Moreover, LY294002 could slightly ameliorate the miR-199a-3p inhibitor-stimulated PI3K/AKT signalling pathway and angiogenesis.

CONCLUSION

MiR-199a-3p upregulation ameliorated HG-stimulated angiogenesis of hRMECs by modulating the PI3K/AKT pathway through inhibiting VEGF. Although retinal neovascularization in vivo has not been studied, these in vitro findings provide more evidence for the role of miR-199a-3p upregulation against HG-induced angiogenesis.

Minimally interface vitrectomy for rhegmatogenous retinal detachment with a single break in young patients

Purpose

This study evaluates a new surgical technique consisting of minimal vitreous removal under air (minimal interface vitrectomy; MIV) to reduce postoperative complications while preserving the ability to address surgical factors at the retinal break.

Methods

This retrospective analysis examined the outcomes of minimal interface vitrectomies in consecutive cases, with a minimum 12-month follow-up period, of primary rhegmatogenous retinal detachment (RRD), recurrent RRD after pars plana vitrectomy (PPV), or failed surgery after primary scleral buckling surgery (SBS).

Results

Twelve eyes of 12 patients with RRD underwent MIV. The total surgical duration was 190–300 s (mean, 245.25 s). Eight (66.7%) eyes were treated with cryotherapy, and 4 (33.3%) with endolaser to seal the retinal break. Successful, complete retinal reattachment was achieved in all eyes and maintained during follow-up. No intra- or postoperative complications occurred and no patients developed inflammation or cataract during follow-up.

Conclusion and Importance

We effectively removed traction and subretinal fluid and treated breaks with endolaser or cryotherapy by using a novel minimal interface vitrectomy technique in this selected population.

Aqueous Inflammation and Ischemia-Related Biomarkers in Neovascular Glaucoma with Stable Iris Neovascularization

Purpose: To characterize the aqueous levels of inflammation and ischemia-related biomarkers in a spectrum of retinal ischemic conditions, including neovascular glaucoma (NVG) with stable iris neovascularization after pan retinal photocoagulation (PRP) and anti-VEGF treatment. Methods: Aqueous samples were collected from 139 eyes including NVG (n = 12), stable NVG (n = 26), CRVO (n = 11), NPDR (n = 18), PACG (n = 18), PDR (n = 25), BRVO (n = 7) and cataract (n = 22). The levels of VEGF-A, IL-8 and EPO were measured with ELISA. Results: Aqueous VEGF-A significantly decreased after anti-VEGF and PRP, from 983.79 ± 821.16 pg/ml in the NVG group (n = 11) to 256.50 ± 51.14 pg/ml in the stable NVG group (n = 24) (P = .015). Aqueous VEGF-A in stable NVG group (256.50 ± 51.14 pg/ml, n = 24) was significantly higher (ANOVA, P < .001) than in CRVO (212.10 ± 19.84 pg/ml, n = 7, P = .017), NPDR (221.18 ± 38.21 pg/ml, n = 14, P = .015), BRVO (213.14 ± 48.50 pg/ml, n = 6, P = .028) and cataract group (185.30 ± 34.35 pg/ml, n = 22, P < .001). Aqueous IL-8 in stable NVG group (74.82 ± 10.78 pg/ml, n = 24) was significantly higher (ANOVA, P < .001) than in CRVO (65.19 ± 15.34 pg/ml, n = 11, P = .032) and cataract group (54.11 ± 12.28 pg/ml, n = 22, P < .001). Aqueous EPO in stable NVG group (17.48 ± 3.02 pg/ml, n = 24) was significantly higher (ANOVA, P < .001) than in BRVO (14.98 ± 2.57 pg/ml, n = 7, P = .034) and cataract group (13.50 ± 2.65 pg/ml, n = 22, P < .001). Aqueous concentrations of VEGF-A and IL-8 correlated positively with IOP (r = 0.413, P < .001, r = 0.349, P < .001, respectively, r = correlation coefficient). VEGF-A correlated positively with IL-8 and EPO (P < .001, P = .002, respectively). IL-8 correlated positively with EPO (P < .001). Conclusions: The aqueous levels of VEGF-A, IL-8 and EPO in NVG patients with stable iris neovascularization, who had received PRP and anti-VEGF, were still significantly higher than in control groups with some retinal ischemic conditions.

Lamellar macular hole in diabetic retinopathy

PURPOSE

To describe the clinical features and surgical outcomes of diabetic retinopathy-associated lamellar macular hole and compare them with those of idiopathic lamellar macular hole.

METHODS

A total of 17 eyes with diabetic retinopathy-associated lamellar macular hole and 30 eyes with idiopathic lamellar macular hole undergoing surgery were retrospectively enrolled. Baseline best-corrected visual acuity, preoperative optical coherence tomography characteristics, and final best-corrected visual acuity were compared between two groups.

RESULTS

Both the baseline and the final best-corrected visual acuity in the diabetic retinopathy group were significantly worse than those in the idiopathic group (p = 0.029 for baseline, p = 0.002 for final). Lamellar macular hole in diabetic retinopathy tended to have a wider opening (p < 0.001) and a thinner residual base (p = 0.023). The width and height of parafoveal schisis in diabetic retinopathy-associated lamellar macular hole were both larger than those in idiopathic lamellar macular hole (p < 0.001 for both). After operation, both groups achieved significant improvement in best-corrected visual acuity (p < 0.01 for both).

CONCLUSION

Compared with idiopathic group, diabetic retinopathy-associated lamellar macular hole had worse baseline best-corrected visual acuity, wider defect, and more pronounced parafoveal schisis. However, significant visual improvement could be obtained after operation. All cases in both groups achieved good anatomical outcomes with normalization of foveal contour and reduction of parafoveal schisis.

Innate immune response in retinal homeostasis and inflammatory disorders

Innate immune cells such as neutrophils, monocyte-macrophages and microglial cells are pivotal for the health and disease of the retina. For the maintenance of retinal homeostasis, these cells and immunosuppressive molecules in the eye actively regulate the induction and the expression of inflammation in order to prevent excessive activation and subsequent tissue damage. In the disease context, these regulatory mechanisms are modulated genetically and/or by environmental stimuli such as damage-associated molecular patterns (DAMPs), and a chronic innate immune response regulates or contributes to the formation of diverse retinal disorders such as uveitis, retinitis pigmentosa, retinal vascular diseases and retinal fibrosis. Here we summarize the recent knowledge regarding the innate immune response in both ocular immune regulation and inflammatory retinal diseases, and we describe the potential of the innate immune response as a biomarker and therapeutic target.

Biomarkers for PVR in rhegmatogenous retinal detachment

PURPOSE

Various profibrotic and proinflammatory cytokines have been found upregulated in uncomplicated primary retinal detachment (pRD), but without providing a uniform picture. Here, we compare the cyto- and chemokine profiles in pRD with and without proliferative vitreoretinopathy (PVR) in an attempt to unravel relevant differences not in single cytokines, but in the cytokine profiles at diagnosis.

METHODS

Undiluted vitreous fluid (VF) was obtained at the beginning of surgery from 174 eyes with pRD without relevant PVR (maximally grade B; group 1; n = 81) and with moderate or advanced PVR requiring a gas tamponade (group 2; n = 49) or silicon oil filling (group 3; n = 44). VF of eyes undergoing macular hole (MH) surgery served as controls (group 4; n = 26). Forty-three cytokines were quantified in parallel using a multiplex cytokine analysis system (Bioplex). For all comparisons we applied Holm's correction to control for multiple comparisons.

RESULTS

44.9% of group 2 eyes presented grade C1 and 55.1% C2-C3, whereas 86.4% of group 3 eyes exhibited a PVR grade of C2-D. CCL19 was the only cytokine that displayed higher concentrations in the vitreous of eyes with PVR C1 compared to lower PVR grades. Eyes with PVR C2-D showed higher levels of CCL27, CXCL6, IL4, IL16, CXCL10, CCL8, CCL22, MIG/CXCL9, CCL15, CCL19, CCL 23 and CXCL12 compared to controls. Interestingly, no difference of cytokine levels was detected between C1 and C2-D PVR.

CONCLUSIONS

CCL19 may represent a potential biomarker for early PVR progression that holds promise for future diagnostic and therapeutic applications.

β‑elemene inhibits oxygen‑induced retinal neovascularization via promoting miR‑27a and reducing VEGF expression

The present study aimed to investigate the significant role of β-elemene in mouse models of oxygen-induced retinopathy (OIR). C57BL/6J neonatal mice were used to establish OIR models. They were divided into four groups: Normoxia, OIR, OIR control and OIR‑treated. Mice in the OIR group were exposed to 75±5% oxygen for 5 days and returned to a normal oxygen environment on postnatal day 12 (P12). The OIR treated group was intravitreally injected with 1 µl β‑elemene on P12 and subsequently returned to a normal oxygen environment for 5 days (P12‑P17). Retinas were obtained on P17. Retinal neovascularization (RNV) was detected using adenosine diphosphatase staining and analyzed by counting the nuclei of neovascular endothelial cells. Vascular endothelial growth factor (VEGF) expression was determined by reverse transcription‑quantitative polymerase chain reaction, immunohistochemistry and western blot analysis. MicroRNA (miRNA/miR) microarrays were used to screen out differentially expressed miRNAs between the OIR and β‑elemene‑treated groups. Binding the 3'‑untranslated region (UTR) of VEGF and miR‑27a was confirmed using luciferase assays. It was found that high oxygen concentrations accelerated RNV and increased the number of preretinal neovascular cells; β‑elemene treatment reduced these effects. VEGF mRNA and protein expression was higher in the OIR and OIR control groups, compared with the normoxia and OIR‑treated groups. Further, it was shown that miR‑22, miR‑181a‑1, miR‑335‑5p, miR‑669n, miR‑190b, miR‑27a and miR‑93 were upregulated in the OIR‑treated group, and downregulated in the OIR group. The prediction websites TargetScan and miRanda revealed that VEGF contained a potential miR‑27a binding site in its 3'‑untranslated region (UTR). Luciferase assays demonstrated that miR‑27a directly bound to the 3'‑UTR of VEGF. In vitro experiments demonstrated that miR‑27a inhibited VEGF expression. In addition, β‑elemene treatment upregulate miR‑27a expression in vivo and in vitro. When miR‑27a expression was depleted by miR‑27a inhibitor, the protective effect of β‑elemene on RNV was eliminated. The present study demonstrated that β‑elemene reduced RNV in mouse OIR models via miR‑27a upregulation, leading to reduced VEGF expression. This finding may contribute to the development of novel therapeutic strategies for human retinopathy.

Inflammatory mediators in the vitreal reflux of patients with diabetic macular edema

PURPOSE

To quantify inflammatory, growth/angiogenic, and tissue remodeling mediators in vitreal reflux (VR) in patients with diabetic macular edema (DME), as collected at first and third intravitreal anti-vascular endothelial growth factor (anti-VEGF, ranibizumab) injection.

METHODS

Thirty (30) consecutive patients (type-2 diabetes mellitus) with visual impairments due to DME and undergoing the first (untreated DME) or the third (treated DME) intravitreal injection of anti-VEGF were included in the study. At the time of surgery, patients were subjected to clinical assessment and spectral domain-optical coherence tomography (SD-OCT), including central retinal thickness (CRT), macular volume, and outer nuclear layer/retinal pigment epithelial (ONL/RPE) measurements. VR sampling was performed at the time of needle removal and subjected to customized protein-array, Western blotting (WB), Ella™ microfluidic, and/or enzyme-linked immunosorbent assay (ELISA) analysis. Biostrumental and biochemical data were collected just prior to the surgery and are representative of disease state. Clinical, biostrumental, and numerous biomarkers and cytokines were statistically compared.

RESULTS

Decreased CRT values were detected in treated DME retinas, as compared to untreated ones (p ≤ 0.05). Differences in VEGF and other mediator expressions between treated and untreated DME were detected in VR samples. Particularly, osteopontin (p ≤ 0.05), interleukin 6 (IL6) (p ≤ 0.05), and VEGF (p ≤ 0.1) values were decreased after treatment. Significant changes were validated by WB, ELISA, and Ella™ analysis.

CONCLUSION

Overall, the biostrumental and biochemical data suggest the presence of a specific pattern of inflammation in VR after treatment. The data would suggest the presence of other mechanisms and mediators, in addition to VEGF, accountable for DME progression.

New model of proliferative vitreoretinopathy in rabbit for drug delivery and pharmacodynamic studies

Blinding retinal diseases become more epidemic as the population ages. These diseases, such as diabetic retinopathy and macular edema, are of chronic nature and require protracted drug presence at the disease site. A sustained intravitreal porous silicon delivery system with dexamethasone (pSiO₂-COO-DEX) was evaluated in a new rabbit model of proliferative vitreoretinopathy (PVR) in a real treatment design. In contrast to the pretreatment design model, pSiO₂-COO-DEX was intravitreally injected into the eyes with active inflammation. Subretinal injection of vascular endothelial growth factor (VEGF) and Matrigel induced a late-onset vitreoretinal inflammation that gradually developed into PVR. This method mimics the human disease better than PVR induced by either intravitreal cell injection or trauma. The pSiO₂-COO-DEX intervened eyes had minimal PVR, while balanced saline solution or free dexamethasone intervened eyes had significantly more PVR formation. In addition, adding VEGF to the Matrigel for subretinal injection induced greater inflammation and retinal neovascularization in comparison to only Matrigel injected under the medullary ray. Clinical and pathological examinations, including fundus fluorescein angiography and optical coherence tomography, confirmed these changes. In the current study, neither subretinal injection of Matrigel or subretinal injection of VEGF and Matrigel induced choroidal neovascularization. However, the current PVR model demonstrates a chronic course with moderate severity, which may be useful for drug screening studies.