Proteomic study of vitreous in proliferative diabetic retinopathy patients after treatment with aflibercept:a quantitative analysis based on 4D label-free technique

AIM:To identify different metabolites,proteins and related pathways to elucidate the causes of proliferative diabetic retinopathy(PDR)and resistance to anti-vascular endothelial growth factor(VEGF)drugs,and to provide biomarkers for the diagnosis and treatment of PDR.METHODS:Vitreous specimens from patients with diabetic retinopathy were collected and analyzed by Liquid Chromatography-Mass Spectrometry(LC-MS/MS)analyses based on 4D label-free technology.Statistically differentially expressed proteins(DEPs),Gene Ontology(GO),Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway representation and protein interactions were analyzed.RESULTS:A total of 12 samples were analyzed.The proteomics results showed that a total of 58 proteins were identified as DEPs,of which 47 proteins were up-regulated and 11 proteins were down-regulated.We found that C1q and tumor necrosis factor related protein 5(C1QTNF5),Clusterin(CLU),tissue inhibitor of metal protease 1(TIMP1)and signal regulatory protein alpha(SIRPα)can all be specifically regulated after aflibercept treatment.GO functional analysis showed that some DEPs are related to changes in inflammatory regulatory pathways caused by PDR.In addition,protein-protein interaction(PPI)network evaluation revealed that TIMP1 plays a central role in neural regulation.In addition,CD47/SIRPαmay become a key target to resolve anti-VEGF drug resistance in PDR.CONCLUSION:Proteomic analysis is an approach of choice to explore the molecular mechanisms of PDR.Our data show that multiple proteins are differentially changed in PDR patients after intravitreal injection of aflibercept,among which C1QTNF5,CLU,TIMP1 and SIRPαmay become targets for future treatment of PDR and resolution of anti-VEGF resistance.

Intravitreal conbercept injection with panretinal photocoagulation for high-risk proliferative diabetic retinopathy with vitreous hemorrhage

AIM:To assess the clinical efficacy and safety of combining panretinal photocoagulation(PRP)with intravitreal conbercept(IVC)injections for patients with high-risk proliferative diabetic retinopathy(HR-PDR)complicated by mild or moderate vitreous hemorrhage(VH),with or without diabetic macular edema(DME).METHODS:Patients diagnosed with VH with/without DME secondary to HR-PDR and received PRP combined with IVC injections were recruited in this retrospective study.Upon establishing the patient’s diagnosis,an initial IVC was performed,followed by prompt administration of PRP.In cases who significant bleeding persisted and impeded the laser operation,IVC was sustained before supplementing with PRP.Following the completion of PRP,patients were meticulously monitored for a minimum of six months.Laser therapy and IVC injections were judiciously adjusted based on fundus fluorescein angiography(FFA)results.Therapeutic effect and the incidence of adverse events were observed.RESULTS:Out of 42 patients(74 eyes),29 were male and 13 were female,with a mean age of 59.17±12.74y(33-84y).The diabetic history was between 1wk and 26y,and the interval between the onset of visual symptoms and diagnosis of HR-PDR was 1wk-1y.The affected eye received 2.59±1.87(1-10)IVC injections and underwent 5.5±1.02(4-8)sessions of PRP.Of these,68 eyes received PRP following 1 IVC injection,5 eyes after 2 IVC injections,and 1 eye after 3 IVC injections.Complete absorption of VH was observed in all 74 eyes 5-50wk after initial treatment,with resolution of DME in 51 eyes 3-48wk after initial treatment.A newly developed epiretinal membrane was noted in one eye.Visual acuity significantly improved in 25 eyes.No complications such as glaucoma,retinal detachment,or endophthalmitis were reported.CONCLUSION:The study suggests that the combination of PRP with IVC injections is an effective and safe modality for treating diabetic VH in patients with HR-PDR.

Evaluation of VEGF gene polymorphisms and proliferative diabetic retinopathy in Mexican population

AIM： To assess if the included vascular endothelial growth factor （VEGF） polymorphisms rs3025035, rs3025021 and rs2010963 are associated to proliferative retinopathy in a Mexican population with type 2 diabetes mellitus （T2DM）. METHODS： A case-control study was conducted in adult individuals with T2DM associated to proliferative retinopathy or non-proliferative retinopathy from Oct. 2014 to Jun. 2015 from the Retina Department of the Asociation to Prevent Blindness in Mexico. The selected patients were adults with a diagnosis of T2DM ≥5y. All subjects had a comprehensive ocular examination and the classification of the retinopathy severity was made considering the Early Treatment Diabetic Retinopathy Study （ETDRS） standardization protocols. Genomic DNA was extracted from whole fresh blood. All samples were genotyped by qPCR for selected VEGF polymorphisms. Hardy-Weinberg equilibrium was calculated by comparing Chi-square values between the expected and the observed values for genotype counts.RESULTS： In total 142 individuals were enrolled, 71 individuals with T2DM and associated proliferative retinopathy and 71 individuals with non-proliferative retinopathy. One-sided Fisher’s exact test was performed for rs3025021 [OR （95% CI）=0.44（0.08-2.2）; P=0.25] and rs2010963 [OR （95% CI）=0.63（0.25-1.6）; P=0.23]. The minor allelic frequencies obtained were 26% for rs3025021, 10% for rs3025035 and 61% for rs2010963. The pairwise linkage disequilibrium between the three SNP was assessed, and was as follows： rs3025021 vs rs3025035： D’=1.0, r2=0.1043, P≤0.0001; rs3025021 vs rs2010963： D’=0.442, r2=0.0446, P=0.149; rs3025035 vs rs2010963： D’=0.505, r2=0.0214, P=0.142.CONCLUSION： This is the first analysis involving VEGF polymorphisms and proliferative diabetic retinopathy in a Mexican population. A major finding of the present study is that none of the polymorphisms studied was significantly associated with proliferative retinopathy. Based on these results, we can infer that different populations have different associations for the same polymorphisms.

Changes in vitreous VEGF, bFGF and fibrosis in proliferative diabetic retinopathy after intravitreal bevacizumab

AIMTo evaluate the relationship between intravitreal bevacizumab (IVB) treatment and the levels of vitreous vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and vitreous-retina surface fibrosis in patients with proliferative diabetic retinopathy (PDR).METHODSThis study was a prospective, open-label, controlled, randomized clinical trial. Sixty-eight eyes of PDR patients (n=53) and macular hole patients (n=15) were enrolled in this study. Thirty-four eyes of the PDR patients received IVB before vitrectomy. Twenty-three of the 34 PDR patients received IVB treatment 5d before vitrectomy (subgroup a), and 11 of the 34 PDR patients received IVB treatment greater than 2wk prior to vitrectomy (subgroup b). Nineteen of the PDR patients did not receive IVB treatment at any time prior to vitrectomy. The levels of bFGF and VEGF in vitreous samples were measured using enzyme-linked immunosorbent assay (ELISA) and the degree of vitreoretinal fibrosis was characterized using clinical data and data obtained intra-operatively.RESULTSIn PDR patients, VEGF and bFGF levels were significantly increased compared to non-PDR (control) subject's eyes (P<0.01). In PDR patients, vitreous VEGF levels were significantly decreased following IVB treatment compared to PDR patients that did not receive IVB treatment (P<0.01). The degree of vitreoretinal fibrosis was significantly increased in subgroup b compared to subgroup a(P<0.05) and to patients that did not receive IVB (P<0.05). Vitreous bFGF levels were significantly greater in subgroup b than subgroup a (P<0.01) or in patients who did not receive IVB treatment (P<0.05). A Spearman's rank correlation test indicated that higher levels of vitreous bFGF, but not VEGF, correlated with the degree of vitreoretinal fibrosis.CONCLUSIONWe found that bFGF levels increase in PDR patient's vitreous after IVB treatment longer than two weeks prior to vitrectomy and correlated with the degree of fibrosis after IVB treatment. These findings suggest vitreous fibrosis is increased in PDR patients after IVB treatment may be due to increased levels of bFGF.

Panretinal photocoagulation versus panretinal photocoagulation plus intravitreal bevacizumab for high-risk proliferative diabetic retinopathy

AIM： To evaluate the effects of panretinal photocoagulation （PRP） compared with PRP plus intravitreal bevacizumab （IVB） in patients with high-risk proliferative diabetic retinopathy （PDR） according to the Early Treatment Diabetic Retinopathy Study criteria.METHODS： The data were collected retrospectively from the eyes of high-risk PDR patients, which were divided into two groups. After treated with standard PRP, the eyes were randomly assigned to receive only PRP （PRP group） or PRP plus intravitreal injection of 1.25 mg of bevacizumab （PRP-Plus group）. Patients underwent complete ophthalmic evaluation, including best corrected visual acuity （BCVA）, intraocular pressure （IOP）, and new vessel size in fluorescein angiography （FA） and optical coherence tomography for the assessment of central subfield macular thickness （CSMT） at baseline and at weeks 12 （±2）, 16 （±2）, 24 （±2） and 48 （±2）. Main outcome measures also included vitreous clear-up time and neovascularization on the disc （NVD） regression time. Adverse events associated with intravitreal injection were investigated.RESULTS： Thirty consecutive patients （n=36 eyes） completed the 48-week follow-up. There was no significant difference between the PRP and PRP-Plus groups with respect to age, gender, type or duration of diabetes, area of fluorescein leakage from active neovascularizations （NVs）, BCVA or CSMT at baseline. The mean vitreous clear-up time was 12.1±3.4wk after PRP and 8.4±3.5wk after PRP combined with IVB. The mean time interval from treatment to complete NVD regression on FA examination was 15.2±3.5wk in PRP group and 12.5±3.1wk in PRP-Plus group. No significant difference in CSMT was observed between the groups throughout the study period. However, the total area of actively leaking NVs was significantly reduced in the PRP-Plus group compared with the PRP group （P〈0.05）. Patients received an average of 1.3 injections （range： 1-2）. Ten eyes （27.8%） underwent 2 injections. Two eyes had ocular complication of PDR progression to dense vitreous hemorrhage （VH）. No major adverse events were identified.CONCLUSION： The adjunctive use of IVB with PRP is associated with a greater reduction in the area of active leaking NVs than PRP alone in patients with high-risk PDR. Short-term results suggest combined IVB and PRP achieved rapid clearance of VH and regression of retinal NV in the treatment of high-risk PDR. Further studies are needed to determine the effect of repeated intravitreal bevacizumab injections and the proper number of bevacizumab injections as an adjuvant.

Ocular surface changes in type II diabetic patients with proliferative diabetic retinopathy

AIM: To detect and analyze the changes on ocular surface and tear function in type II diabetic patients with proliferative diabetic retinopathy(PDR), an advanced stage of diabetic retinopathy(DR), using conventional ophthalmic tests and the high-resolution laser scanning confocal microscopy.METHODS: Fifty-eight patients with type II diabetes were selected. Based on the diagnostic criteria and stage classification of DR, the patients were divided into the non-DR(NDR) group and the PDR group. Thirty-six patients with cataract but no other ocular and systemic disease were included as non-diabetic controls. All the patients were subjected to the conventional clinical tests of corneal sensitivity, Schirmer I test, and corneal fluorescein staining. The non-invasive tear film break-up time(NIBUT) and tear interferometry were conducted by a Tearscope Plus. The morphology of corneal epithelia and nerve fibers was examined using the high-resolution confocal microscopy.RESULTS: The NDR group exhibited significantly declined corneal sensitivity and Schirmer I test value, as compared to the non-diabetic controls(P 【0.001). The PDR group showed significantly reduced corneal sensitivity, Schirmer I test value, and NIBUT in comparison to the non-diabetic controls(P 【0.001).Corneal fluorescein staining revealed the progressively injured corneal epithelia in the PDR patients. Moreover,significant decrease in the corneal epithelial density andmorphological abnormalities in the corneal epithelia and nerve fibers were also observed in the PDR patients.CONCLUSION: Ocular surface changes, including blunted corneal sensitivity, reduced tear secretion, tear film dysfunction, progressive loss of corneal epithelia and degeneration of nerve fibers, are common in type II diabetic patients, particularly in the diabetic patients with PDR. The corneal sensitivity, fluorescein staining scores,and the density of corneal epithelial cells and nerve fibers in the diabetic patients correlate with the duration of diabetes. Therefore, ocular surface of the patients with PDR should be examined regularly by conventional approaches and confocal microscopy to facilitate early diagnosis and treatment of keratopathy.

Angiogenesis-related cytokines in serum of proliferative diabetic retinopathy patients before and after vitrectomy

AIM: To evaluate serum concentrations of angiogenesis-related cytokines in proliferative diabetic retinopathy (PDR) before and after vitrectomy. METHODS: Serum samples were collected from 30 PDR patients with varying severity before and after vitrectomy. Serum concentrations of vascular endothelial growth factor (VEGF), pigment epithelium-derived factor (PEDF), interleukin-8 (IL-8) and interferon-inducible protein-10 (IP-10) were determined by enzyme-linked immunosorbent assays(ELISA). RESULTS: Serum concentrations of VEGF, PEDF, IL-8 and IP-10 were significantly higher in PDR patients than that in controls, respectively (P<0.05). VEGF concentration decreased significantly in postoperative samples than that in preoperative samples (P<0.05). The concentrations of PEDF, IL-8 and IP-10 did not exhibit significant changes after vitrectomy. CONCLUSION: Elevated cytokines levels in serum may be diagnostically useful in PDR. Angiogenesis-related cytokines play important roles in the development of PDR, and would instruct the risk assessment of pathogenetic condition in PDR patients.

Ahmed valve implantation for neovascular glaucoma after 23-gauge vitrectomy in eyes with proliferative diabetic retinopathy

·AIM: To report on the outcome of Ahmed glaucoma valve (AGV) implantation for the management of neovascular glaucoma (NVG) after 23 -gauge vitrectomy for proliferative diabetic retinopathy (PDR). ·METHODS: Twelve medically uncontrolled NVG with earlier 23 -gauge vitrectomy for PDR underwent AGV implantation. The control of intraocular pressure (IOP), preoperative and postoperative best -corrected visual acuity, the development of intraoperative and postoperative complications were evaluated during the follow-up. ·RESULTS: The mean follow-up was 15.4±4.3 months (9-23 months). Mean preoperative IOP was 49.4±5.1mmHg and mean postoperative IOP at the last visit was 17.5 ± 1.6mmHg. The control of IOP was achieved at the final follow -up visits in all patients, however, 8 of 12 patients still needed anti-glaucoma medication (mean number of medications, 0.8±0.7). The visual acuity improved in nine eyes, and the visual acuity unchanged in three eyes at the final follow -up visits. The complications that occurred were minor hyphema in three eyes, choroid detachment in two eyes, and the minor hyphema and choroid detachments were reabsorbed without any surgical intervention. ·CONCLUSION: AGV implantation is a safe and effective procedure that enables successful IOP control and vision preservation in the NVG patients with the history of earlier 23-gauge vitrectomy for PDR.·

Effect of intravitreal conbercept treatment before vitrectomy in proliferative diabetic retinopathy

AIM： To evaluate the safety and efficacy of intravitreal conbercept（IVC） injections as pretreatment for pars plana vitrectomy（PPV） in severe proliferative diabetic retinopathy（PDR）. METHODS： This was a retrospective chart review of all patients who underwent PPV for PDR from January 2014 to October 2016. Patients who underwent IVC injection before PPV were assigned to the IVC group; the others were assigned to the control group. The IVC was performed 3-7 d before surgery in the IVC group. All the eyes in the two groups were operated by the same doctor to complete the vitrectomy. Intraoperative complications and the changes in best-corrected visual acuity（BCVA） before and after surgery were compared between the two groups. RESULTS： A total of 68 eyes of 63 patients（22 eyes in the IVC group and 46 eyes in the control group） were examined. The risk of intraoperative bleeding was lower in the IVC group（2/22） than in the control group（25/46, P=0.000）. Furthermore, the use of endodiathermy was significantly lower in the IVC group（1/22） than in the control group（12/46, P=0.047）. The surgical time in the IVC group（112.64±34.52 min） was significantly shorter than in the control group（132.85±40.04 min, P〈0.05）. Compared to the BCVA before surgery, the mean BCVA was significantly improved after surgery for both groups（P〈0.05）. CONCLUSION： PPV is an effective treatment and can improve vision in patients with PDR. Preoperative intravitreal injection of conbercept could reduce the chances of intraoperative bleeding and the use of endodiathermy and shorten the operative time, which are beneficial in the management of PDR.

Phosphorylation of alphaB-crystallin in epiretinal membrane of human proliferative diabetic retinopathy

AIMTo examine phosphorylation of alphaB-crystallin (p-&#x003b1;BC), a vascular endothelial growth factor (VEGF) chaperone, and immunohistochemically investigate relationship between p-&#x003b1;BC, VEGF and phosphorylated p38-mitogen-activated protein kinase (p-p38 MAPK) in the epiretinal membrane of human proliferative diabetic retinopathy (PDR).METHODSEleven epiretinal membranes of PDR surgically excised were included in this study. Two normal retinas were also collected from enucleation tissues due to choroidal melanoma. Paraformaldehyde-fixed, paraffin-embedded tissue sections were processed for immunohistochemistry with anti-p-&#x003b1;BC, VEGF, CD31, and p-p38 MAPK antibodies.RESULTSImmunoreactivity for p-&#x003b1;BC was observed in all of the epiretinal membranes examined, where phosphorylation on serine (Ser) 59 showed strongest immunoreactivity in over 70% of the membranes. The immunolocalization of p-&#x003b1;BC was detected in the CD31-positive endothelial cells, and co-localized with VEGF and p-p38 MAPK in PDR membranes. Immunoreactivity for p-&#x003b1;BC, however, was undetectable in endothelial cells of the normal retinas, where p-p38 MAPK immunoreactivity was less marked than PDR membranes.CONCLUSIONPhosphorylation of &#x003b1;BC, in particular, phosphorylation on Ser59 by p-p38 MAPK may play a potential role as a molecular chaperon for VEGF in the pathogenesis of epiretinal membranes in PDR.

Roles of tissue plasminogen activator and its inhibitor in proliferative diabetic retinopathy

AIMTo investigate the role of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) in proliferative diabetic retinopathy (PDR) and to discuss the correlations among t-PA, PAI and vascular endothelial growth factor (VEGF) expressions.

Bimodal imaging of proliferative diabetic retinopathy vascular features using swept source optical coherence tomography angiography

AIM： To categorize neovessels morphology and to detect response to anti-angiogenic therapy by using structural and angiographic modes of swept source optical coherence tomography（SS-OCT）.METHODS： Thirty-two eyes with neovessels at disc（NVD） and neovessels elsewhere（NVE）-as diagnosed by fluorescein angiography-were included. Cross sectional OCT images of disc and macular regions were registered to enface OCT angiography（OCTA）, B-scan blood flow over lay and density maps. Three eyes received antiangiogenic treatment.RESULTS： Pin point registration of cross-sectional OCT and OCTA images differentiated active NVD with vascular elements from fibrous or equivalent fibrovascular elements. En face images delineated NVE as vascular tufts or area of filling while cross-sectional images differentiated NVE from microvascular intraretinal abnormality（IRMA）. All cases were associated with enlargement of foveal avascular zone and or areas of capillary non perfusion. Regressed NVD appeared as ghost vessel or pruned vascular loops after injection.CONCLUSION： Structural and angiographic modes of SS-OCT can detect, characterize and categorize the pattern of wide spectrum of neovessels based on blood flow data and density maps. It is potentially useful to detect ischemic changes in the vascular bed and regression of NVD after therapeutic regimens providing substitute for invasive techniques.

Comprehensive assessment of growth factors,inflammatory mediators, and cytokines in vitreous from patients with proliferative diabetic retinopathy

AIM: To assess alterations in growth factors, inflammatory mediators, and cytokines associated with vitreous-retinal diseases in vitreous humor from patients with proliferative diabetic retinopathy(PDR), and to identify potential new treatment targets and strategies.METHODS: Control vitreous samples were collected from patients with macular hole, epiretinal membranes, or rhegmatogenous retinal detachments, and PDR samples from patients with complications of PDR, who required pars plana vitrectomy. Specimens were stored at-80℃ and then investigated by Luminex multi-factor assay. Parametric and nonparametric analyses of demographic characteristics and cytokine expression levels were conducted using SPSS.RESULTS: There were no significant differences in demographic characteristics between patients with and without PDR. Expression levels of growth factors [plateletderived growth factor(PDGF)-AA, glial cell line-derived neurotrophic factor(GDNF), and vascular endothelial growth factor A(VEGFA)], inflammatory mediators [interleukin(IL)-8, IL-11, and tumor necrosis factor-α(TNF-α)] and cytokines [chemokine C-X-C ligand(CXCL)10, interferon-γ(IFN-γ), and granulocyte macrophage-colony stimulating factor(GM-CSF)] were significantly elevated in vitreous humor from patients with PDR compared with those in the control group(all P<0.05). Further, VEGFA levels were lower in patients with PDR treated with anti-VEGF injection than those who were not(P<0.05), and there was no difference between the PDR group treated with anti-VEGF and controls(P>0.05).CONCLUSION: This proof-of-concept study demonstrates the potential for combinational therapeutic strategies to ameliorate diabetic retinopathy progression by targeting growth factors, inflammatory factors, and cytokines, in addition to VEGFA.

Adverse outcomes in type 1 diabetic pregnant women with proliferative diabetic retinopathy

AIM: To report maternal and fetal adverse outcomes, in spite of appropriate treatment and regular follow up, in diabetic pregnant women with proliferative diabetic retinopathy. METHODS: Case series of four young pregnant diabetics aged between 20 and 25 years with type 1 diabetes mellitus and proliferative diabetic retrinopathy. RESULTS: The maternal adverse outcomes were abortion in one patient, pre-eclampsia and preterm delivery in one patient, and renal failure requiring dialysis in one patient. The fetal adverse outcomes were neonatal death in one case and premature baby in another case. CONCLUSION: These cases highlight the fact that diabetic pregnant women should be closely followed up by the obstetricians and physicians when they have proliferative retinopathy. The proliferative diabetic retinopathy should be considered as a part of the assessment when counseling a diabetic woman in antenatal check up and also in the follow up visits during pregnancy.

Newly diagnosed diabetes mellitus patients presenting with proliferative diabetic retinopathy as an initial sign

AIM: To investigate the clinical features of newly diagnosed diabetes mellitus(NDM) patients showing proliferative diabetic retinopathy(PDR) as an initial sign. ·METHODS: As a retrospective case series,the medical records of a total of four hundred and thirty-two patients who underwent a vitrectomy due to PDR were reviewed to find the subjects. Of 432 patients,six cases of NDM patients showing PDR as an initial sign were included and analyzed with their systemic and ocular features. Main outcome measures: the systemic features and ocular features [preoperative and postoperative best corrected visual acuity(BCVA),intraoperative findings]. ·RESULTS: The mean onset age of visual symptoms was 36.3 years old. The mean serum insulin and C-peptide titer was below the normal range. The mean fasting plasma glucose was 178mg/dL and the mean postprandial 2h plasma glucose was 306mg/dL. The mean HbA1c at diagnosis was 11.02%. In all cases,an acute progressive fibrovascular proliferation was observed. Intraoperative retinal tears were found in three cases of six. The mean preoperative BCVA was +0.67 ± 0.58 logMAR and the mean BCVA at postoperative 6 months was +0.20±0.30 logMAR. ·CONCLUSION: All patients were considered to have latent autoimmune diabetes in adults(LADA). A rapid deterioration of kidney function as well as poor diabetic control status at diagnosis was observed in all six cases. The ocular features of the patients showed acute progressive fibrovascular proliferation and relatively favorable postoperative visual acuity.

Prognosis value of Chinese Ocular Fundus Diseases Society classification for proliferative diabetic retinopathy on postoperative visual acuity after pars plana vitrectomy in type 2 diabetes

AIM: To compare the postoperative visual acuity among eyes with proliferative diabetic retinopathy(PDR) of different stages after pars plana vitrectomy(PPV) in type 2 diabetic patients. METHODS: A retrospective study was conducted for PDR eyes undergoing PPV in type 2 diabetic patients. All patients were divided into three groups based on Chinese Ocular Fundus Diseases Society(COFDS) classification for PDR: Group A(primary vitreous hemorrhage), Group B(primary fibrovascular proliferation) and Group C(primary vitreous hemorrhage and/or fibrovascular proliferative combined with retinal detachment). The postoperative visual acuity and the change between postoperative and preoperative visual acuity were compared among three groups. The associated risk factors for postoperative visual acuity were analyzed in the univariate and multiple linear aggression. RESULTS: In total, 195 eyes of 195 patients were collected in this study, including 71 eyes of 71 patients in Group A, 75 eyes of 75 patients in Group B and 49 eyes of 49 patients in Group C. The eyes in Group A got better postoperative best-corrected visual acuity(BCVA) compared to the eyes in Group B and C(0.48±0.48 vs 0.89±0.63, P<0.001;0.48±0.48 vs 1.04±0.67, P<0.001;respectively). The eyes in Group A got more improvement of BCVA compared to the eyes in Group B and C(1.07±0.70 vs 0.73±0.68, P=0.004;1.07±0.70 vs 0.77±0.78, P=0.024;respectively). In the multiple linear regression analysis, primary fibro-proliferative type(β=0.194, 95%CI=0.060-0.447, P=0.01), retinal detachment type(β=0.244, 95%CI=0.132-0.579, P=0.02), baseline log MAR BCVA(β=0.192, 95%CI=0.068-0.345, P=0.004), silicone oil tamponade(β=0.272, 95%CI=0.173-0.528, P<0.001) was positively correlated with postoperative log MAR BCVA. Eyes undergoing phacovitrectomy had better postoperative BCVA(β=-0.144, 95%CI=-0.389 to-0.027, P=0.025). CONCLUSION: PDR eyes of primary vitreous hemorrhage type usually have better visual acuity prognosis compared to primary fibrovascular proliferation type and retinal detachment type. COFDS classification for PDR may have a high prognostic value for postoperative visual outcome and surgical management indications.

Optimal timing of preoperative intravitreal anti-VEGF injection for proliferative diabetic retinopathy patients

AIM: To analyze concentrations of vascular endothelial growth factor(VEGF) and fibrosis-related factors in vitreous fluid of proliferative diabetic retinopathy(PDR) patients pretreated with intravitreal anti-VEGF injections(IVI) at different time periods prior to pars plana vitrectomy(PPV), and their correlation with the degree of vitreoretinal fibrosis and explore the optimal timing of preoperative IVI.METHODS: The prospective case-control study from January 2019 to July 2020 included 31 eyes with PDRrelated complications(PDR group) and 21 eyes with nondiabetic ocular disease(control group) requiring PPV. PDR eyes were divided into four groups based on timing of PPV: 3 d after IVI(3-day group);5 d after IVI(5-day group);7 or more days after IVI(≥7-day group);and no IVI. Vitreous fluid samples(0.5-1.0 m L) were collected prior to switching on the infusion before routine 23-G PPV. Concentrations of VEGF, basic fibroblast growth factor(b FGF), periostin(PN), interleukin(IL)-6, IL-8, and tumor necrosis factor(TNF)-α were measured by immunoassay, and concentration differences for each cytokine were compared among the groups. The degree of vitreoretinal fibrosis was graded intraoperatively, and the correlation between the changes in cytokine levels and the severity of vitreoretinal fibrosis was analyzed by univariate ordinal logistic regression analysis.RESULTS: PDR eyes without IVI had significantly higher VEGF, b FGF, PN, and IL-6 concentrations than nondiabetic eyes(all P<0.05), and had a significantly higher concentration of VEGF(P<0.05) and a significantly lower concentration of IL-8(P<0.05) than PDR eyes with IVI. Statistically significant differences were also observed for concentrations of VEGF, b FGF, PN, IL-6, and IL-8 among 3-day, 5-day, and ≥7-day groups(all P<0.05);meanwhile there was no significant difference in TNF-α among groups(P=0.226). The 5-day group had the lowest concentration of VEGF and the ≥7-day group had the highest concentration of b FGF and PN. The degree of vitreoretinal fibrosis was significantly higher in the ≥7-day group compared to the 3-day(P=0.015) and 5-day group(P=0.039), and vitreoretinal fibrosis correlated significantly with concentrations of b FGF, PN, IL-6, and IL-8(all P<0.05). Univariate ordinal logistic regression analysis showed that b FGF was an independent risk factor for the severity of vitreoretinal fibrosis in PDR patients pre-treated with IVI.CONCLUSION: The vitreous concentrations of VEGF, b FGF, PN, IL-6, and IL-8 change after pretreatment with IVI before PPV in PDR patients. The degree of vitreoretinal fibrosis is higher in patients with a longer time between IVI treatment and PPV, which may be related to the angiofibrosis switch. The results suggest that PPV should be performed 5 d after IVI administration in PDR patients.

Inner limiting membrane peeling prevents secondary epiretinal membrane after vitrectomy for proliferative diabetic retinopathy

·AIM:To evaluate the role of internal limiting membrane(ILM)peeling in preventing secondary epiretinal membrane(ERM)formation in pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR).·METHODS:This retrospective study analyzed the medical records of patients who underwent PPV for PDR and were followed up for minimum 3 mo.ILM peeling was performed based on the intraoperative surgeons’judgments.ERM was assessed by optical coherence tomography photography.The relationship between ILM peeling and postoperative ERM was analyzed.·RESULTS:In total,212 eyes from 197 patients were included in this study.The incidence of secondary ERM in the ILM non-peeling group was significantly higher than that in the ILM peeling group(37.0%vs 14.0%;P<0.001).Multivariate logistical regression revealed that ILM peeling was highly associated with the prevention of secondary ERM development[odds ratio 0.38;95%confidence interval0.17-0.86;P<0.05].·CONCLUSION:ILM peeling during PPV for PDRs can effectively reduce the incidence of secondary ERM development and is worth consideration by vitreoretinal surgeons.

Effect of intravitreal ranibizumab on fibrovascular membranes in patients with proliferative diabetic retinopathy

AIM: To assess the effects of intravitreal ranibizumab(IVR) on angiogenesis and glial activity of the fibrovascular membrane(FVM) in patients with proliferative diabetic retinopathy(PDR). METHODS: Forty-two eyes from 42 patients with PDR requiring vitrectomy were included and divided into two groups: control group(n=16) did not receive IVR, while IVR group(n=26) underwent IVR 5 d before vitrectomy. FVM specimens were collected by the same surgeon during the interventions. Histopathological morphology was examined by hematoxylin-eosin(H-E) staining and cell densities in the FVM was assessed. Microvessels were outlined by immunohistochemical staining of CD31 and microvessel density(MVD) assessed as an index of FVM angiogenesis. Dual-color immunofluorescence staining, and confocal microscopy was used to detect co-localization and relative expression levels of glial fibrillary acidic protein(GFAP) and α-smooth muscle actin(α-SMA) as markers of glialmesenchymal transition(GMT). The GMT index(GI;ratio of relative GFAP/α-SMA expression) was used to semi-quantify the degree of GMT or glial activity of FVMs. RESULTS: H-E staining showed similar vascularization in both groups, with microvessels and scattered stromal cells in the matrix. Infiltrated cell densities did not differ significantly between the two groups(P>0.05). The MVD of the IVR group(130.62±15.46/mm~2) was significantly lower than that of the controls(142.25±19.16/mm~2, P<0.05). In both groups, all sections were strongly immunostained for GFAP and α-SMA. The Pearson’s correlation coefficients(PCC) of intensity of automated pixel count of two markers indicated GFAP and α-SMA co-stained well and GMT participated in the remolding of FVMs in PDR. The mean relative GFAP expression in the IVR group was significantly lower, whereas that of α-SMA was significantly higher than in controls(P<0.05). GI in the IVR group(1.10±0.10) was significantly lower than in the controls(1.21±0.12, P<0.05). CONCLUSION: IVR can reduce angiogenesis, glial activity of FVM and promote glial-fibrotic transformation by reducing MVD and promoting GMT but does not decrease the cell density in patients with PDR.

Comment on roles of tissue plasminogen activator and its inhibitor in proliferative diabetic retinopathy

Dear Sir,We congratulate Wu et al for their study entitled＂Roles of tissue plasminogen activator and its inhibitor in proliferative diabetic retinopathy＂.The authors investigated the effects of tissue plasminogen activator（t-PA）and plasminogen activator inhibitor（PAI）in the pathogenesis of proliferative diabetic retinopathy（PDR）.The authors reported that t-PA and PAI are involved in the pathogenesis of PDR.