PERSISTENT OVERPRODUCTION OF INTRAOCULAR VASCULAR ENDOTHELIAL GROWTH FACTOR AS A CAUSE OF LATE VITREOUS HEMORRHAGE AFTER VITRECTOMY FOR PROLIFERATIVE DIABETIC RETINOPATHY

Combined Use of Anti-VEGF Drugs Before and During Pars Plana Vitrectomy for Severe Proliferative Diabetic Retinopathy

INTRODUCTION

This study aimed to evaluate the combined administration of anti-vascular endothelial growth factor (anti-VEGF) drugs before and during pars plana vitrectomy (PPV) and to explore its efficacy and safety in the treatment of patients with severe proliferative diabetic retinopathy (PDR).

METHODS

This retrospective case series included consecutive patients who underwent PPV. Patients were categorized into two groups: the preoperative group was injected with anti-VEGF drugs before PPV, and the combination group was injected with anti-VEGF drugs before and during PPV. Preoperative, intraoperative, and postoperative clinical data were collected for analysis. The main outcome measures were changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) and occurrence of postoperative vitreous cavity haemorrhage (POVCH).

RESULTS

In total, 63 eyes of 60 patients with severe PDR were analysed. The operative duration and occurrence of intraoperative haemorrhage, iatrogenic retinal breaks, and silicone oil tamponade were similar between the two groups. The benefits on BCVA, and CRT after 1 week postoperatively, were more obvious in the combination group (P < 0.01). Combination therapy had the potential to reduce the incidence of POVCH. No ocular or systemic adverse events occurred in either group.

CONCLUSIONS

The combined use of anti-VEGF drugs before and during PPV in patients with severe PDR not only includes the advantages of preoperative injection, but also has more significant prognostic benefits and favourable safety profiles.

Effect of Intravitreal Conbercept Injection on Complications of Pars Plana Vitrectomy in Patients with Proliferative Diabetic Retinopathy

BACKGROUND

The effect of intravitreal conbercept (IVC) before pars plana vitrectomy (PPV) on surgical complications in patients with proliferative diabetic retinopathy (PDR) was observed.

METHODS

A total of 152 patients with PDR operated on in Jiangsu Provincial People's Hospital from November 2019 to November 2020 were divided into two groups: 124 patients in the preoperative intravitreal conbercept injection + PPV group (IVC group) and 28 patients in the PPV only group (No-IVC group). Vitreous samples were collected in all eyes of patients who underwent vitrectomy, and the content of VEGF-A was measured by Luminex. The effect of conbercept on intraoperative and postoperative complications of PDR was assessed.

RESULTS

The content of VEGF in the vitreous of the IVC group was significantly lower than that in the No-IVC group (64.50 ± 58.40 pg/mL vs. 805.17 ± 417.60 pg/mL, p < 0.001). During postoperative follow-up, early postoperative vitreous hemorrhage (VH) occurred in 13 of 142 eyes (9.15%). Compared with the No-IVC group, PDR patients with VH and fibrovascular membrane (FVM) or high complexity in the IVC group had lower intraoperative bleeding rates (p < 0.05). The early postoperative hemorrhage rate in the IVC group was lower than in the No-IVC group (6.03% vs. 23.08%, p < 0.05). The number of intraoperative electrocoagulation and iatrogenic retinal holes in the IVC group was significantly lower than in the No-IVC group (p < 0.05). There were no significant differences in intraocular hypertension and NVG numbers between the two groups. Visual acuity in both groups improved after PPV surgery, reaching the highest level in the 3rd month after the operation.

CONCLUSIONS

IVC before PPV can reduce the level of VEGF-A in the vitreous body and reduce surgical complications.

Correlation between the Outcome of Vitrectomy for Proliferative Diabetic Retinopathy and Erythrocyte Hematocrit Level and Platelet Function

We investigate-d whether biomarkers such as red blood cell hematocrit (Hct), platelet count (PLT), mean platelet volume (MPV), and platelet distribution width (PDW) are useful prognostic indicators of postoperative macular edema (ME) after vitrectomy for proliferative diabetic retinopathy (PDR). A total of 42 eyes of 42 patients with PDR who underwent vitrectomy between January 2018 and May 2020 were analyzed retrospectively. We divided them into two groups according to whether treatment was required for postoperative ME and compared the relationship between Hct, PLT, MPV, and PDW and the onset of postoperative ME. The group that received postoperative treatment (group T) comprised 11 eyes of 11 patients, and the group that did not (group N) comprised 31 eyes of 31 patients. The age (years) was 52.0 ± 3.1 in group T and 60.0 ± 11.6 in group N. When appropriate statistical analysis was performed for comparison between groups, significant differences were found in age (p = 0.05), insulin use (p = 0.03), preoperative intraocular pressure (p = 0.05), diastolic blood pressure (p = 0.03), and Hct (p = 0.04). Multivariate logistic regression analysis was performed, and a significant difference was found in Hct (p = 0.02). These results suggest that Hct might be useful as a predictor of ME after PDR 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.

Monitoring intraocular proangiogenic and profibrotic cytokines within 7 days after adjunctive anti-vascular endothelial growth factor therapy for proliferative diabetic retinopathy

PURPOSE

To monitor the intraocular proangiogenic and profibrotic cytokine profiles within 7 days after intravitreous injection of conbercept (IVC) for patients with proliferative diabetic retinopathy (PDR).

METHODS

This prospective, randomized controlled, consecutive, comparative study included 157 eyes with PDR. Participant eyes underwent sham IVC or IVC and subsequent vitrectomy at days 2, 3, 4, 5, 6, 7 postinjection. The intraocular cytokines profiles were measured using beaded assay methods.

RESULTS

After IVC, the vascular endothelial growth factor (VEGF)-A level in PDR vitreous decreased rapidly by approximately 10 times at day 2 (p = 0.00001) and kept at a low level at days 3, 4, 5, 6, 7 (p < 0.001, each compared with IVC-sham group). Similar tendency of the change in VEGF-A was observed in aqueous humour. The level of placenta growth factor (PIGF) in aqueous humour decreased 2 days after IVC whereas returned to baseline level after 5 days. The vitreous profibrotic cytokines, tissue growth factor (TGF)-β1, TGF-β2, TGF-β3 and connective tissue growth factor did not increase after IVC in each group.

CONCLUSION

We observed a remarkable and rapid decrease in intraocular VEGF-A, temporal decrease in PIGF from day 2 to day 4, increase in VEGF-C and VEGF-D from day 2 onwards, but no profibrotic switch in PDR eyes after IVC. The findings might suggest that ideal vitrectomy timing might be around 3 days after IVC.

Visual outcomes and complications following one-way air-fluid exchange technique for vitreous hemorrhage post vitrectomy in proliferative diabetic retinopathy patients

BACKGROUND

To evaluate the efficacy and outcomes of one-way surgical technique for the treatment of vitreous hemorrhage post vitrectomy on proliferative diabetic retinopathy (PDR) patients.

METHODS

This retrospective case series include 47 PDR patients who had vitrectomy with balanced saline solution tamponade and have developed vitreous hemorrhage without significant absorption. The one-way air-fluid exchange procedure which involves the application of a 0.22-μm pore size filter to exchange about 4.5-5.5 ml of fluid with a 10 ml syringe was performed on 47 patients (47 eyes). Post procedure, additional treatments were administered when needed. Best corrected visual acuity (BCVA), occurrence of intra-procedural and post-procedural complications were recorded and analyzed.

RESULTS

A total of 47 eyes of 47 PDR patients with a mean age of 50.8 ± 12.0 years were reviewed. Because of vitreous hemorrhage or tractional retinal detachment of PDR, all 47 eyes underwent vitrectomy with balanced saline solution tamponade prior to the exchange procedure. Four patients (8.51%) and 43 patients (91.5%) were diagnosed with type 1 diabetes mellitus (T1DM), or type 2 diabetes mellitus (T2DM), respectively. All 47 eyes were given the one-way air-fluid exchange procedure in the treatment room. Forty-two cases (89.4%) needed the air-fluid exchange procedure only once, 4 cases (8.51%) underwent the procedure twice, and 1 case (2.13%) was given the procedure three times, followed by additional retinal photocoagulation and one intravitreal injection of Conbercept. In addition to the procedure, no further treatment was needed for 5 eyes (10.6%) while additional retinal laser treatment was provided for 41 eyes (87.2%). The BCVA at the final follow-up was significantly improved from the initial acuity baseline in all cases. No complications were observed during the follow-ups.

CONCLUSION

This one-way air-fluid exchange procedure can effectively exchange the vitreous hemorrhage and improve visual acuity of PDR patients who develop vitreous rehemorrhage post vitrectomy without obvious complications.

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.

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.

Change of Vascular Endothelial Growth Factor Levels following Vitrectomy in Eyes with Proliferative Diabetic Retinopathy

Purpose

To study the change of concentrations of vascular endothelial growth factor (VEGF) in vitreous cavity after vitrectomy in eyes with proliferative diabetic retinopathy (PDR).

Methods

In this retrospective study, intravitreal fluid samples were taken at baseline (beginning of the vitrectomy) and postoperatively (several days later after vitrectomy) at the time of prophylactic injection of bevacizumab in forty-eight eyes of forty-eight patients with PDR. Postvitrectomy fluid samples were divided into four groups according to the time interval between the vitrectomy and the injection (group 1, 3–5 days; group 2, 6–10 days; group 3, 11–15 days; group 4, 16–21 days; twelve eyes in each group). Postvitrectomy fluid sample was paired with baseline sample for each eye. VEGF concentrations in the samples were determined by enzyme-linked immunosorbent assay. Recurrent vitreous hemorrhage and neovascular glaucoma within six months postvitrectomy were also analyzed.

Results

Overall, the intravitreal VEGF level after vitrectomy (median, 36.95 pg/ml; range, 3.2–1,299.4 pg/ml) was significantly less than the VEGF level at baseline (median, 704.5 pg/ml; range, 30.6–1,981.1 pg/ml). Postoperative and baseline VEGF levels were significantly correlated (r = 0.499, p < 0.01). Both the absolute value of postoperative VEGF concentrations and the postop/baseline VEGF ratios declined with time and dramatically decreased in groups 3 and 4. In only two eyes, the postoperative VEGF level was even higher than the baseline VEGF level (postop/baseline VEGF ratio >1), and recurrent vitreous hemorrhage developed within six months in these two eyes.

Conclusions

After vitrectomy for PDR, intravitreal VEGF levels decreased substantially in the majority of patients, while persistent high-VEGF level occurred in a few individuals. Postoperative VEGF levels and postop/baseline VEGF ratio declined with time. The postop/preop VEGF ratio may serve as a predictor for late complications.

Intravitreal ranibizumab injection at the end of vitrectomy for diabetic vitreous hemorrhage (Observational Study)

To evaluate the outcomes and complications of intravitreal injections of ranibizumab in patients during pars plana vitrectomy for treatment of diabetic vitreous hemorrhage. This retrospective, observational, comparative study included 103 patients (103 eyes) who underwent pars plana vitrectomy for treatment of diabetic vitreous hemorrhage. Sixty-six patients received an intravitreal injection of 0.05 mg (0.05 cc) of ranibizumab at the end of surgery. Main outcome measures were the occurrence of recurrent early vitreous hemorrhage, reoperation, intraocular pressure, best corrected visual acuity. Mean follow-up time was 6 months. The rate of rebleeding in the intravitreal ranibizumab (IVR) group was 6.1% (4 eyes), which is significantly lower than the control group (24.3%, 9 eyes, P < .01). The incidence of postoperative diabetic vitreous hemorrhage (PDVH) was significantly lower in the IVR group than the control group, OR=0.26, 95% CI= (0.06, 0.95). Visual acuity 6 months after operation was better in IVR group (P<.01) There was no difference in mean intraocular pressure between the 2 groups (P=.56). The present clinical study suggests that intravitreal injection of ranibizumab is effective in the prevention of postoperative diabetic vitreous hemorrhage in eyes undergoing pars plana vitrectomy for the treatment of diabetic vitreous hemorrhage.