Vitreous Vascular Endothelial Growth Factor Concentrations Research Articles

Vitreous Levels of Vascular Endothelial Growth Factor and Platelet-Derived Growth Factor in Patients with Proliferative Diabetic Retinopathy: A Clinical Correlation.

Background: The global epidemic status of diabetic retinopathy (DR) and its burden presents an ongoing challenge to health-care systems. It is of great interest to investigate potential prognostic biomarkers of DR. Such markers could aid in detecting early stages of DR, predicting DR progression and its response to therapeutics. Herein, we investigate the prognostic value of intravitreal concentrations of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) in a DR cohort. Materials and methods: Vitreous sample acquisition was conducted at King Abdullah University Hospital (KAUH) between December 2020 and June 2022. Samples were obtained from any patient scheduled to undergo a pars plana vitrectomy (PPV) for any indication. Included patients were categorized into a DR group or a corresponding non-diabetic (ND) control group. Demographics, clinicopathological variables, standardized laboratory tests results, and optical coherence tomography (OCT) data were obtained for each included individual. Intravitreal concentrations of VEGF and PDGF were assessed using commercial enzyme-linked immunosorbent assay (ELISA). Results: A total of 80 eyes from 80 patients (DR group: n = 42 and ND control group: n = 38) were included in the analysis. The vitreous VEGF levels were significantly higher in the DR group compared to the ND control group (DR group 5744.06 ± 761.5 pg/mL versus ND control group 817.94 ± 403.1 pg/mL, p = 0.0001). In addition, the vitreous PDGF levels were also significantly higher in the DR group than those in the ND control group (DR group 4031.51 ± 410.2 pg/mL versus ND control group 2691.46 ± 821.0 pg/mL, p = 0.001). Bassline differences between test groups and clinical factors impacting VEGF and PDGF concentrations were investigated as well. Multiple regression analysis indicated PDGF as the sole independent risk factor affecting best-corrected visual acuity (BCVA) at the last follow-up visit: the higher the PDGF vitreous levels, the worst the BCVA. Conclusions: Vitreous concentrations of VEGF and PDGF are correlated with DR severity and may exhibit a possible prognostic potential value in DR. Further clinical and experimental data are warranted to confirm the observed findings and to help incorporate them into daily practice.

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

To analyze concentrations of vascular endothelial growth factor (VEGF) and fibrosis-related factors in vitreous fluid of proliferative diabetic retinopathy (PDR) patients pre-treated 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. The prospective case-control study from January 2019 to July 2020 included 31 eyes with PDR-related complications (PDR group) and 21 eyes with non-diabetic ocular disease (control group) requiring PPV. PDR eyes were divided into four groups based on timing of PPV: 3d after IVI (3-day group); 5d after IVI (5-day group); 7 or more days after IVI (≥7-day group); and no IVI. Vitreous fluid samples (0.5-1.0 mL) were collected prior to switching on the infusion before routine 23-G PPV. Concentrations of VEGF, basic fibroblast growth factor (bFGF), 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. PDR eyes without IVI had significantly higher VEGF, bFGF, PN, and IL-6 concentrations than non-diabetic 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, bFGF, 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 bFGF 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 bFGF, PN, IL-6, and IL-8 (all P<0.05). Univariate ordinal logistic regression analysis showed that bFGF was an independent risk factor for the severity of vitreoretinal fibrosis in PDR patients pre-treated with IVI. The vitreous concentrations of VEGF, bFGF, 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 angio-fibrosis switch. The results suggest that PPV should be performed 5d after IVI administration in PDR patients.

42-OR: Association of Vitreous Retinol Binding Protein 3 with Inflammatory Cytokines and Progression of Diabetic Retinopathy in Type 1 and Type 2 Diabetes

Although inflammatory cytokines and vascular endothelial growth factor (VEGF) have been proposed to underlie the progression of diabetic retinopathy (DR) , there remains an important need to identify biomarkers for early stages of DR. Findings from the Joslin Medalist Study, composed of individuals who have had insulin-dependent diabetes for 50 years or longer, showed that Retinol Binding Protein 3 (RBP3) was significantly higher both in retina and vitreous samples with no to mild DR compared to those with proliferative DR (PDR) . In this study, we examined vitreous and plasma samples from 2people with type 1 and type 2 diabetes from the Joslin Beetham Eye Institute and Medalist Study to evaluate the relationship between vitreous RBP3, inflammatory cytokines, and DR severity and progression. PDR was associated with lower levels of IL- (P=0.007) , IFN-γ (P=0.001) , and higher levels of IL-15 (P=0.01) and IL-6 (P=0.02) in vitreous. Vitreous VEGF was positively associated with increasing DR severity in surgical samples (P&amp;lt;0.05) . Plasma VEGF was not associated with vitreous VEGF concentration. No significant relationships were found between inflammatory markers in the vitreous and plasma from the same individual. Increased vitreous RBP3 concentration was associated with less severe DR in all eyes (P&amp;lt;0.0001) , post-mortem (P&amp;lt;0.0001) and surgical samples from type 1 and type 2 diabetic patients (P=0.03) with diabetes duration of &amp;lt;50 years (mean±SD 27±13 years) . Higher vitreous RBP3 concentration was associated with lower risk of PDR onset (P&amp;lt;0.0001) . Lower vitreous TNF-α, TNF-β, and VEGF were associated with increased vitreous RBP3 concentration (P&amp;lt;0.05, all) . These findings suggest that inflammatory cytokines and risk of DR worsening may be decreased by RBP3, supporting its potential use as biomarker for severity and progression of DR. Disclosure W.Fickweiler: None. J.D.Cavallerano: None. L.P.Aiello: Consultant; KalVista Pharmaceuticals, Inc., Novo Nordisk, Stock/Shareholder; KalVista Pharmaceuticals, Inc. J.Sun: Consultant; American Diabetes Association, American Medical Association, Research Support; Adaptive Sensory Technology, Boehringer Ingelheim International GmbH, Genentech, Inc., Jaeb Center for Health Research, Janssen Pharmaceuticals, Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk, Optovue, Incorporated, Physical Sciences, Inc, Roche Pharmaceuticals. G.L.King: Advisory Panel; Medtronic, Research Support; Janssen Pharmaceuticals, Inc. H.Park: None. K.Park: None. M.G.Mitzner: None. D.B.Robinson: None. T.Chokshi: None. T.Boumenna: None. J.Gauthier: None. I.Wu: None. Funding American Diabetes Association (7-21-PDF-022) ; National Eye Institute (R01EYE26080-01) , the National Institute of Diabetes and Digestive and Kidney Diseases and National Institutes of Health (DP3-DK-094333-01) ; JDRF (17-2013-310) ; the Dianne Nunnally Hoppes Fund; the Beatson Pledge Fund

Increased angiogenic factors in the aqueous and vitreous humors after disinsertion of extraocular muscle and the effects of triamcinolone acetate injection

The four extraocular rectus muscles in the rabbits were disinserted for induction of anterior segment ischemia (ASI) and the changes in the concentrations of prostaglandin E2 (PGE2), hypoxia-inducible factor-1 (HIF-1α), and vascular endothelial growth factor (VEGF) in the aqueous and vitreous humor were evaluated. Disinsertion of four rectus muscles in rabbits was performed in the right eyes of rabbits (ASI group). The concentrations of PGE2, HIF-1α, and VEGF in the aqueous and vitreous humor were measured at 1, 3, 6, 12, and 24 h by ELISA. The concentrations were compared with those of the fellow eyes (contralateral group) and normal healthy eyes (control group). Subconjunctival injection of triamcinolone acetonide (TA) was administered and three cytokine concentrations in the aqueous humor and vitreous humor were measured at 12 h after TA injection. A total of 48 eyes from 28 rabbits were included. The concentrations of PGE2, HIF-1α, and VEGF in the aqueous humor in the ASI and contralateral groups were significantly higher than those in the control group (p < 0.05, all). The aqueous and vitreous humor concentrations of VEGF in eyes with simultaneous TA injection were significantly lower than were those in the ASI group (p = 0.02, all). The concentration of PGE2, HIF-1α, and VEGF in the aqueous humor was increased after induction of ASI and TA injection seems to be effective in inhibiting VEGF elevation in ASI.

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.

BackgroundProliferative 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.MethodsThis 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.ResultsThe 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.ConclusionSeven 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.

Effectiveness of prophylactic intravitreal bevacizumab injection to proliferative diabetic retinopathy patients with elevated preoperative intraocular VEGF in preventing complications after vitrectomy.

PurposeThis study aimed to elucidate the effects of intravitreal bevacizumab (IVB) injections for the prevention of post-vitrectomy complications in proliferative diabetic retinopathy (PDR) patients with elevated vitreous vascular endothelial growth factor (VEGF) concentration.DesignProspective case series.MethodsThirty-three patients (42 eyes) with PDR who underwent primary vitrectomy in the Department of Ophthalmology, Tokyo Medical University Hospital were studied. We measured VEGF concentrations in vitreous humor collected at the time of vitrectomy using ELISA. IVB injections were performed after vitrectomy in patients with vitreous VEGF levels exceeding 1,000 pg/mL. New bleeding occurring within 1 month of vitrectomy was defined as early vitreous hemorrhage (VH).Main outcome measureThe incidence of complications after vitrectomy including postoperative early VH.ResultsIVB injections were administered to 11 eyes (26%) with vitreous VEGF concentrations exceeding 1,000 pg/mL. None of the 11 eyes that received an IVB injection developed early VH. Among 31 eyes (74%) with vitreous VEGF concentrations lower than 1,000 pg/mL, two eyes (6%) developed early VH after vitrectomy.ConclusionsProphylactic IVB injections administered to patients with elevated preoperative intraocular VEGF concentrations were effective in preventing post-vitrectomy early VH.

586-P: Vitreous and Serum Measurements of Retinol Binding Protein 3 in the Clinical Evaluation of Diabetic Retinopathy

The Joslin 50-Year Medalist Study discovered that elevated photoreceptor-secreted Retinol Binding Protein 3 (RBP3) in the retina and vitreous of individuals with extreme duration of type 1 diabetes is associated with long-term protection from advanced diabetic retinopathy (DR), independent of glycemic control. This represents the first neuroretinal protein identified with potential protective activity against the toxic effects of hyperglycemia on the retinal vasculature, a major cause of DR onset and worsening. We extended these findings by correlating vitreous and serum RBP3 concentrations and examining associated clinical characteristics. We developed a novel RBP3 ELISA assay with high sensitivity (0.1-1 nM), specificity (no detection of immunoglobulin G, albumin, or RBP4), and intra-and inter-assay correlations (p&amp;lt;0.001 and p=0.003, respectively). Vascular endothelial growth factor (VEGF) concentrations were measured by ELISA. A total of 101 individuals with type 1 diabetes with mean±SD diabetes duration 44.6±21.0 years, A1c 7.6±1.2%, age 73.5±8.9 years, with 46.5% female, were evaluated. Vitreous RBP3 concentration correlated with vitreous VEGF concentration, age, diabetes duration, cardiovascular disease, and DR severity (p&amp;lt;0.05, all). Mean serum RBP3 concentration was 1000-fold less than vitreous, but correlated with vitreous RBP3 concentration and DR severity (p&amp;lt;0.05, all), even after adjusting for age and A1c. There was a strong association between lower serum RBP3 concentration and increasing age and diabetes duration (p&amp;lt;0.01 and p&amp;lt;0.05, respectively). Vitreous (p=0.01), but not plasma VEGF concentrations were positively associated with DR severity. The fact that serum RBP3 and not plasma VEGF concentrations correlate with DR severity, suggests potential for the systemic measurement of RBP3 in the clinical evaluation of DR and its therapeutic outcomes. Disclosure W. Fickweiler: None. H. Yokomizo: None. K. Park: None. S.M. Paniagua: None. I. Wu: None. D.M. Pober: None. V. Bahnam: None. A. Clermont: Consultant; Self; KalVista Pharmaceuticals, Inc. L.P. Aiello: Advisory Panel; Self; Novo Nordisk A/S. Consultant; Self; Decision Resources Group, KalVista Pharmaceuticals, Inc., Mingsight, Retinal Solutions. Stock/Shareholder; Self; KalVista Pharmaceuticals, Inc. Other Relationship; Self; Optos. J.K. Sun: Research Support; Self; Adaptive Sensory Technology, Boston Micromachines Corporation, Genentech, Inc., KalVista Pharmaceuticals, Inc., Optovue, Incorporated. Other Relationship; Self; Genentech, Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk Inc. G.L. King: Research Support; Self; Sanofi. Funding National Eye Institute (R01EY026080-01); National Institute of Diabetes and Digestive and Kidney Diseases (DP3DK094333-01); JDRF (17-2013-310); Thomas J. Beatson, Jr. Foundation Inc.; Dianne Nunnally Hoppes Scholarship Fund

Expression of CD147 in laser-induced rat choroidal neovascularization model

Background The pathology of choroidal neovascularization (CNV) is not clear.CD147 plays a critical role in angiogenesis through activating matrix metalloproteinases (MMPs) and degradation of extracellular matrix (ECM). However, the study of CD147 in CNV is rare. Objective This study was to investigate the expression of CD147 and vascular endothelial growth factor (VEGF) in laser-induced rat CNV model. Methods Thirty clean BN rats were divided into normal control group (six rats) and laser group (24 rats) according to the random number table.CNV was induced on laser photocoagulation group rats using 532 nm multiple-wave length photocoagulation.The development of CNV was followed up by fundus fluorescence angiography (FFA) on 1 day, 7, 14 and 21 days post-photocoagulation.The expression of CD147 protein in retinal pigment epithelium(RPE)-choroid-sclera complex was examined by Western blot in normal control group and 1 day, 7, 14, 21 days post-photocoagulation group.The vitreous VEGF concentrations of those groups were detected by ELISA. Results Disk like fluorescein leakage was detected on 7 days after photocoagulation, and CNV was formed on 14 days after photocoagulation.The expressions of CD147 protein were 1.00±0.43, 0.97±0.53, 0.99±0.45, 1.56±0.67 and 2.27±0.54, and the concentrations of vitreous VEGF were (72.96±29.95), (79.36±10.46), (103.82±32.94), (166.05±21.54) and (195.64±39.90)pg/ml in normal control group and 1 day, 7, 14, 21 days post-photocoagulation group, with significant differences among the groups (CD147: F=10.95, P<0.01; VEGF: F=304.50, P<0.01). The expressions of CD147 and VEGF were significantly higher in the 14, 21 days post-photocoagulation groups than those in the normal control group (all at P<0.05). Conclusions The expression of CD147 increases as the induction of CNV, in accordance with the expression of VEGF.CD147 may play an important role in the early development of CNV. Key words: Choroidal neovascularization; CD147; Vascular endothelial growth factor; Matrix metalloproteinases

CORRELATION OF INCREASED INTRAVITREOUS WNT3A WITH VASCULAR ENDOTHELIAL GROWTH FACTOR IN PROLIFERATIVE DIABETIC RETINOPATHY.

To investigate Wnt3a and vascular endothelial growth factor (VEGF) levels in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR) and to examine their correlation with PDR activity. Vitreous samples from 45 eyes with PDR and 28 eyes with nondiabetic macular disease were collected. Active PDR was present in 24 patients and inactive PDR in 21 patients, according to retinal neovascularization. The Wnt3a and VEGF level of vitreous fluid samples were measured by enzyme-linked immunosorbent assay. Comparison revealed that mean intravitreal levels of Wnt3a increased significantly in PDR eyes compared with control eyes (13.55 ng/mL vs. 1.57 ng/mL, P < 0.001). The mean VEGF concentrations in the vitreous fluid of patients with PDR were also higher than those in nondiabetic controls, with the values being 723.21 pg/mL and 20.81 pg/mL, respectively (P < 0.001). In addition, vitreous concentrations of Wnt3a and VEGF were significantly higher in active PDR than in eyes with inactive PDR (P = 0.016 and P = 0.008, respectively). Furthermore, a significant positive correlation was detected between Wnt3a and VEGF levels in the vitreous. Intravitreous levels of Wnt3a and VEGF in patients with PDR are increased and correlated mutually. Wnt3a may be an important player in the development of diabetic retinopathy and its activity in vitreous fluid can be biomarker of PDR.

Vitreous and plasma VEGF levels as predictive factors in the progression of proliferative diabetic retinopathy after vitrectomy.

PurposeTo investigate the vitreous and plasma levels of vascular endothelial growth factor (VEGF) in patients with proliferative diabetic retinopathy (PDR) and to determine whether they predict a disease prognosis after primary vitrectomy.MethodsFifty patients (50 eyes) with PDR who underwent pars plana vitrectomy (PPV) and 56 healthy controls (56 eyes) were enrolled in this retrospective study. Clinical data were collected and analyzed. Vitreous and plasma VEGF concentrations were measured using enzyme-linked immunosorbent assays. VEGF levels and clinical data were compared and analyzed to see if they provide a prognosis of PDR progression after primary vitrectomy at more than 6 months follow-up. Correlation of VEGF concentrations between vitreous fluid and plasma was analyzed.ResultsThe average BCVA was significantly improved after surgery (P<0.001). Vitreous and plasma VEGF levels were significantly elevated in PDR patients than those in healthy controls (P vitreous<0.001; P plasma<0.001). Both vitreous and plasma VEGF levels were significantly higher in PDR progression group than in stable group (P vitreous<0.001; P plasma = 0.004). Multivariate logistic regression analyses showed that the increased vitreous VEGF level was associated with the progression of PDR after primary PPV (OR = 1.539; P = 0.036). Vitreous VEGF level was positively associated with plasma VEGF level in PDR patients (P<0.001).ConclusionThe increased VEGF level in vitreous fluid may be identified as a significant predictive factor for the outcome of vitrectomy in patients with PDR.

Ang-2 upregulation correlates with increased levels of MMP-9, VEGF, EPO and TGFβ1 in diabetic eyes undergoing vitrectomy

Angiogenesis in diabetic retinopathy (DR) is a multifactorial process regulated by hypoxia-induced growth factors and inflammatory cytokines. In addition to the angiogenic switch, the proteolytic processing and altered synthesis of the extracellular matrix are critical steps in this disease. This study was performed to evaluate the levels of matrix metalloproteinase-2 and matrix metalloproteinase-9 (MMP-2 and MMP-9), angiopoietin-1 and angiopoietin-2 (Ang-1 and Ang-2), vascular endothelial growth factor (VEGF), erythropoietin (EPO) and transforming growth factor-β1 (totalTGFβ1) in the vitreous of diabetic eyes undergoing vitrectomy compared with control eyes operated because of macular hole or pucker. Prospective consecutive controlled observational study performed in the unit of vitreoretinal surgery in Finland during the years 2006-2008. Vitreous samples were collected before the start of the conventional 3-ppp vitrectomy. Vitreous MMP-2 and MMP-9, Ang-1 and Ang-2, VEGF, EPO and TGFβ1 concentrations were measured from 69 patients with Type 1 or 2 diabetes and 40 controls. Comparison of eyes with DR with controls revealed that the mean vitreous concentrations of proMMP-2 (p = 0.0015), totalMMP-2 (p = 0.0011), proMMP-9 (p = 0.00001), totalMMP-9 (p < 0.00001), Ang-2 (p < 0.00001), VEGF (p < 0.00001), EPO (p < 0.00001) and totalTGFβ1 (p = 0.000026) were significantly higher in the former group. A multivariate logistic regression analysis suggested intravitreal Ang-2 concentration being the key marker of PDR (p = 0.00025) (OR = 1507.9). The main new finding is that the intravitreal concentrations of Ang-2 correlated significantly with MMP-9, VEGF, EPO and TGFβ1 levels in diabetic eyes undergoing vitrectomy. Thus, these factors could promote retinal angiogenesis synergistically.

Imbalanced levels of angiogenic and angiostatic factors in vitreous, plasma and postmortem retinal tissue of patients with proliferative diabetic retinopathy

A role for vascular endothelial growth factor (VEGF) has been clearly implicated in the pathogenesis of proliferative diabetic retinopathy (PDR). However, other molecules and mechanisms may be operating independently, or in conjunction with VEGF in the pathogenesis of this disease. Therefore, we made an attempt to comparatively investigate the levels of angiogenic and angiostatic factors in vitreous, plasma and postmortem retinal tissue of subjects with Proliferative Diabetic Retinopathy (PDR) compared to control subjects. The vitreous and plasma concentrations of VEGF, EPO (Erythropoietin) and PEDF (Pigment Epithelium Derived Factor) were measured using Enzyme Linked Immunosorbent Assay (ELISA) and the postmortem retinal tissue was subjected to Western blot analysis. The mean vitreous and plasma levels of VEGF and EPO in patients with PDR were significantly (p<0.001) higher than those in subjects without diabetes. Conversely, the vitreous and plasma levels of PEDF were significantly (p<0.001) lower in the PDR patients compared to control subjects. Multivariate logistic-regression analyses indicated that EPO was more strongly associated with PDR than VEGF. The protein expression of the VEGF and EPO in the retinal tissue was significantly higher in PDR and diabetes without complication groups compared to controls. Compared to controls, the protein expression of PEDF was significantly lower in retinal tissues from diabetes patients without complications and in patients with PDR. The fact that the vitreous and plasma levels and the retinal tissue protein expression of EPO were strongly associated with PDR implies a definite role of ‘hypererythropoietinemia' in neovascularization processes.

Correlation of complement fragment C5a with inflammatory cytokines in the vitreous of patients with proliferative diabetic retinopathy

To determine the vitreous concentration of complement fragment C5a in patients with proliferative diabetic retinopathy (PDR) and the relation between C5a and inflammatory cytokines including vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1). Vitreous samples were obtained at the time of vitrectomy from 12 eyes of 11 PDR patients and from 11 eyes of 11 patients without diabetes with macular disease (controls). Vitreous and serum concentrations of human C5a, VEGF, and MCP-1 were quantified using FACS Caliber flow cytometer. Vitreous concentration of C5a increased significantly in patients with PDR [median (range): 928.7 (46.6 to 3,319.4) pg/ml] compared with controls [58.7 (22.2 to 1,432.4) pg/ml; p < 0.01]. In PDR patients, vitreous concentration of C5a correlated significantly with those of VEGF (p < 0.05) and MCP-1 (p < 0.05). Our results suggest that C5a may play an important role in the pathogenesis of PDR and work in concert with inflammatory cytokines such as VEGF and MCP-1 in pathological angiogenesis.

Vascular Endothelial Growth Factor in Plasma and Vitreous Fluid of Patients with Proliferative Diabetic Retinopathy Patients after Intravitreal Injection of Bevacizumab

To investigate plasma and vitreous vascular endothelial growth factor (VEGF) levels after intravitreal bevacizumab (IVB) injection into eyes with proliferative diabetic retinopathy (PDR). Retrospective, interventional, nonrandomized, comparative study. Fifty-six eyes of 56 patients with PDR and 13 eyes of 13 patients with nondiabetic ocular diseases were enrolled. Analysis included evaluation of basic clinical conditions and measurement of vitreous and plasma VEGF concentrations using enzyme-linked immunosorbent assays. PDR eyes without IVB had the highest vitreous VEGF levels; the levels were significant compared with those in the recent IVB group (previous injection within 1 week), the prolonged IVB group (injection more than 1 week previously), and the nondiabetic control group (P = .001, P = .035, P < .001, respectively). The vitreous VEGF level in the recent IVB group was higher than that in prolonged IVB group (P = .035). PDR eyes without IVB had the highest plasma VEGF level, and the level was significant compared with those in the recent IVB group, the prolonged IVB group, and the nondiabetic control group (P < .001, P = .003, P < .001, respectively). The plasma VEGF level in the recent IVB group was lower than that in the prolonged IVB group (P = .003). The vitreous VEGF level was associated significantly with the plasma VEGF level (P = .002). Vitreous and plasma VEGF levels were increased markedly in patients with PDR. VEGF concentrations in vitreous and plasma were decreased significantly after IVB into PDR eyes, and the effect lasted from 4.4 ± 2.2 days to 34.8 ± 33.7 days after injection.

Vitreous Vascular Endothelial Growth Factor Concentrations in Proliferative Diabetic Retinopathy versus Proliferative Vitreoretinopathy

Purpose: To assess vitreous vascular endothelial growth factor (VEGF) concentrations in proliferative diabetic retinopathy (PDR) in comparison to proliferative vitreoretinopathy (PVR). Patients and Methods: Vitreous samples were collected from 69 eyes of 69 patients with traumatic lens dislocation (n = 10), grade B PVR with rhegmatogenous retinal detachment (n = 13), grade C PVR with rhegmatogenous retinal detachment (n = 14), PDR with vitreous hemorrhage (n = 18), and PDR with vitreous hemorrhage and tractional retinal detachment (n = 14). Vitreous fluid samples were obtained at vitrectomy, and the levels of VEGF were measured by enzyme-linked immunosorbent assay. Results: The mean vitreous level of VEGF was 15.14 ± 5.22 pg/ml in eyes with grade B PVR, 99.15 ± 38.58 pg/ml in eyes with grade C PVR, 4,534.01 ± 1,193.28 pg/ml in eyes with vitreous hemorrhage secondary to PDR, 5,157.29 ± 969.44 pg/ml in eyes with vitreous hemorrhage and tractional retinal detachment secondary to PDR, and 16.19 ± 5.76 pg/ml in eyes of the control group with traumatic lens dislocation. Vitreous VEGF concentrations were significantly higher in the patients with grade C PVR, PDR with vitreous hemorrhage and PDR with vitreous hemorrhage and tractional retinal detachment in comparison to the control patients (p < 0.05). A significant alteration was not observed in patients with grade B PVR (p = 0.55). Conclusions: Vitreous VEGF concentrations are increased in PDR and grade C PVR. The high VEGF concentrations could suggest a possible effect of VEGF on advanced PVR.

DOSE OF INTRAVITREAL BEVACIZUMAB (AVASTIN) USED AS PREOPERATIVE ADJUNCT THERAPY FOR PROLIFERATIVE DIABETIC RETINOPATHY

The purpose of this study was to examine the effect of lower than usual doses of intravitreal bevacizumab (Avastin) on vitreous vascular endothelial growth factor (VEGF) concentration and intraoperative bleeding when used as preoperative adjunct therapy in patients undergoing vitrectomy for proliferative diabetic retinopathy. Fifty-two eyes (52 patients) with indications for vitrectomy were studied; 12 received bevacizumab, and 40 did not. The bevacizumab group was given a single intravitreal injection of bevacizumab (0.16-1.25 mg) 3 days before vitrectomy. Numbers of intraoperative coagulation spots administered for hemostasis were compared between the two groups. In both groups, vitreous samples were collected during vitrectomy, and VEGF levels were measured by enzyme-linked immunosorbent assay. The VEGF concentration was 1880.1 +/- 1927.5 in the nonbevacizumab group and 24.9 +/- 25.1 in the bevacizumab group, and the difference was significant (P = 0.0001). Although VEGF concentrations were apparently lower at higher bevacizumab doses, no significant correlation was observed (r = 0.366, P = 0.2425). Numbers of intraoperative coagulation spots differed significantly between the bevacizumab (3.2 +/- 0.8) and nonbevacizumab (5.7 +/- 1.0) groups (P < 0.0001). In the bevacizumab group, there was no correlation between the number of intraoperative coagulation spots and the bevacizumab dose (r = 0.272, P = 0.3919). When intravitreal bevacizumab was administered as preoperative adjunct therapy to patients undergoing vitrectomy for proliferative diabetic retinopathy, the lowest dose tested (0.16 mg) was as effective as the standard dose (1.25 mg) in reducing vitreous VEGF concentrations and also decreasing intraoperative bleeding as measured by the reduced number of coagulation spots.

Apelin in Plasma and Vitreous and in Fibrovascular Retinal Membranes of Patients with Proliferative Diabetic Retinopathy

Apelin is an endogenous ligand for the angiotensin-1-like receptor APJ. Because apelin has been reported to regulate angiogenesis, the authors searched for associations between apelin and proliferative diabetic retinopathy. The study included 55 patients undergoing vitrectomy for proliferative diabetic retinopathy (study group) and 34 patients undergoing vitrectomy for idiopathic preretinal membranes or macular hole (control group). Using enzyme-linked immunosorbent assay, the authors measured the concentrations of apelin and vascular endothelial growth factor (VEGF) in the vitreous and plasma. The expression of apelin and angiotensin-1-like receptor APJ in the excised membranes was examined by fluorescence immunostaining and semiquantitative reverse transcription polymerase chain reaction. Vitreous concentrations of apelin were significantly higher in the study group than in the control group (P = 0.005), whereas plasma concentrations of apelin did not vary significantly (P = 0.66). The vitreous concentrations (P < 0.001) and the plasma concentrations (P = 0.03) of VEGF were significantly higher in the study group than in the control group. Neither the vitreous concentrations of apelin and VEGF (P = 0.47) nor the plasma concentrations of apelin and VEGF (P = 0.19) were significantly associated with each other. In the fibrovascular membranes of the study group, colocalization of the endothelial markers CD31 with the markers for apelin and colocalization of the endothelial markers CD31 and APJ was observed. Expression of apelin mRNA (P = 0.03), APJ mRNA (P = 0.02), and VEGF mRNA (P < 0.01) was significantly higher in fibrovascular proliferative diabetic retinopathy membranes than in idiopathic epiretinal membranes. The apelin/APJ system may be involved in retinal neovascularization during the development of proliferative diabetic retinopathy.

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

To evaluate vitreous vascular endothelial growth factor (VEGF), stromal cell-derived factor 1alpha (SDF-1alpha), interleukins (ILs), and tumor necrosis factor-alpha (TNF-alpha) after intravitreal bevacizumab or triamcinolone acetonide (TA) in eyes with proliferative diabetic retinopathy (PDR). Interventional, consecutive, retrospective, comparative study with a historical control. Forty-seven eyes of 47 patients affected by active PDR were investigated. Bevacizumab (1.25 mg; 19 eyes; bevacizumab group) or TA (4 mg; 10 eyes; TA group) was injected into the vitreous cavity as preoperative adjunctive therapy 7 days before vitrectomy. Eighteen eyes without injection served as controls (control group). The vitreous samples were obtained at vitrectomy and were analyzed for concentrations of total protein, VEGF, SDF-1alpha, IL-1beta, IL-6, IL-8, IL-10, IL-12p70, and TNF-alpha. Vitreous concentrations of VEGF, SDF-1alpha, ILs, and TNF-alpha were compared among bevacizumab, TA, and control groups. Vitreous concentrations of VEGF and SDF-1alpha were lower in bevacizumab and TA groups compared with the control group. The median VEGF level was 0 pg/ml (range, 0-79.2 pg/ml) in the bevacizumab group, 343.5 pg/ml (range, 0-1683.3 pg/ml) in the TA group, and 1202.5 pg/ml (range, 76-4213.9 pg/ml) in the control group. The median SDF-1alpha level was 149.2 pg/ml (range, 0-519.4 pg/ml) in the bevacizumab group, 87.5 pg/ml (range, 0-252.5 pg/ml) in the TA group, and 245.7 pg/ml (range, 0-856.8 pg/ml) in the control group. The differences in both vitreous VEGF and SDF-1alpha concentrations among 3 groups were statistically significant (P<0.001 and P = 0.010, respectively). The eyes with intravitreal bevacizumab demonstrated the lowest vitreous level of VEGF, and the level was statistically significant compared with the eyes with intravitreal TA and control eyes (P<0.001 and P<0.001, respectively). The control eyes had the highest vitreous level of SDF-1alpha, and the level was statistically significant compared with the eyes with intravitreal bevacizumab and TA (P = 0.015 and P = 0.009, respectively). There was no significant difference regarding ILs and TNF-alpha. Intravitreal injection of bevacizumab potentially diminishes not only VEGF but also SDF-1alpha. These findings suggest that intravitreal bevacizumab may influence intraocular mediators beyond VEGF. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Vitreous Levels of Erythropoietin and Vascular Endothelial Growth Factor in Eyes with Retinopathy of Prematurity

To determine the vitreous levels of erythropoietin and vascular endothelial growth factor (VEGF) in eyes with retinopathy of prematurity (ROP) and to study the correlation between the 2 levels. Retrospective case-control study. Forty eyes of 27 infants with stage 4 ROP (4A, 30 eyes; 4B, 10 eyes) were studied. Five eyes of 4 patients with congenital cataract were used as controls. The eyes with ROP were classified by the vascular activity into 3 groups: highly vascular-active ROP (n = 16), moderately vascular-active ROP (n = 10), and mildly vascular-active ROP (n = 14). Eyes with highly vascular-active ROP initially received an intravitreal injection of 0.5 mg bevacizumab and underwent vitrectomy approximately 1 week after the injection. The eyes in the other groups underwent vitrectomy without bevacizumab. Undiluted vitreous samples were obtained at the beginning of vitrectomy, and the vitreous concentrations of erythropoietin and VEGF were measured by enzyme-linked immunosorbent assay. The vitreous concentrations of erythropoietin and VEGF were determined and compared among the 4 groups. The vitreous level of erythropoietin was significantly higher (P<0.05) in the highly and moderately vascular-active ROP eyes than in control eyes. The median concentration of erythropoietin was 744.6 mIU/ml in the highly vascular-active ROP eyes, 729.9 mIU/ml in the moderately vascular-active ROP eyes, 478.0 mIU/ml in the mildly vascular-active ROP eyes, and 0 mIU/ml in control eyes. The vitreous VEGF level was significantly higher (P<0.05) in the moderately vascular-active ROP eyes than in control eyes. The median concentration of VEGF was 44.7 pg/ml in the highly vascular-active ROP eyes that had received an intravitreal bevacizumab injection, 360.8 pg/ml in the moderately vascular-active ROP eyes, 0 pg/ml in the mildly vascular-active ROP eyes, and 11.4 pg/ml in control eyes. There was a significant positive correlation (r = 0.410; P = 0.047) between the erythropoietin and VEGF levels in moderately and mildly vascular-active ROP eyes. The elevated level of erythropoietin and its correlation with the VEGF level in eyes with stage 4 ROP suggest that not only VEGF but also erythropoietin may contribute to the pathogenesis of ROP. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Concentration Gradient of Vascular Endothelial Growth Factor in the Vitreous of Eyes with Diabetic Macular Edema

Vascular endothelial growth factor (VEGF) concentrations in various regions of the vitreous were examined in patients with diabetic macular edema (DME) to explore the possibility of a concentration gradient in the vitreous. Vitreous samples were collected during vitrectomy from 71 eyes of 71 patients with DME and without posterior vitreous detachment who had not undergone panretinal photocoagulation. Vitreous samples were collected from the premacular vitreous and mid-vitreous (group A, 35 eyes), and from the premacular vitreous and peripheral cortical vitreous (group B, 36 eyes). Mean foveal thickness was measured by optical coherence tomography (OCT). Ten eyes of 10 patients with stage 3 macular hole (MH) served as controls. Vitreous VEGF levels were measured by enzyme-linked immunosorbent assay. The VEGF concentration (mean +/- SD; pg/mL) was significantly higher in the premacular vitreous (1386.2 +/- 2134.1) than in the peripheral cortical vitreous (1169.7 +/- 1840.3; P = 0.0216) and mid-vitreous (1080.9 +/- 1534.1; P = 0.0017). The mean foveal thickness measured on OCT correlated significantly with VEGF concentrations in the premacular vitreous, peripheral cortical vitreous, and mid-vitreous (R > 0.62, P < 0.0001, for all). In controls, VEGF concentrations in the premacular vitreous, peripheral cortical vitreous and mid-vitreous were all below the detection limit (<20 pg/mL). In DME, vitreous VEGF concentration correlates with mean foveal thickness measured on OCT. VEGF concentration was higher in premacular vitreous than in mid-vitreous and peripheral cortical vitreous, suggesting diffusion from the macular region to the periphery, and from the posterior to the anterior globe.