Global, regional, and national burdens of intraocular foreign bodies in children and adolescents from 1990 to 2019: a trend analysis.

BACKGROUND: This study aimed to evaluate trends in global, regional, and national burdens of intraocular foreign bodies among children and adolescents (aged 0 - 19 years) between 1990 and 2019 according to age, sex, and socio-demographic index. METHODS: This study obtained data from the Global Burden of Disease Study 2019 and evaluated the number of cases, rates per 100,000 persons, and average annual percentage changes among children and adolescents. The annual percentage changes in the incidence and years lived with disability rates across various age groups were investigated using joinpoint software. RESULTS: For intraocular foreign bodies in children and adolescents, the incidence and year lived with disability rates decreased in all age groups between 1990 and 2019. However, the number of incident cases and years lived with disability increased from 1091.94 [95% uncertainty interval (UI), 610.91-1839.52] and 89,245 (95% UI, 6.65-18.67) in 1990 to 1134.85 (95% UI, 665.01-1867.50) and 92,108 (95% UI, 32,052-192,153) in 2019, respectively. Age was positively correlated with the number of cases, incidence, and years lived with disability rates. However, there were significant decreases in both the incidence and years lived with disability rates among children and adolescents, especially in the 15-18 years age group, males, and most high-income regions. Notably, the incidence and years lived with disability rates were significantly decreased in middle and high-middle socio-demographic index regions but were increased in low and low-middle socio-demographic index regions. CONCLUSIONS: Despite the remarkable progress between 1990 and 2019 in reducing the global burden of intraocular foreign bodies, there has been an increase in the number of cases, with substantial disparity across age groups, sexes, regions, and countries. Our results could inform more effective strategies for reducing the burden among children and adolescents.

Essential contribution of macrophage Tie2 signal mediated autophagy in laser-induced choroidal neovascularization.

Autophagy plays critical roles in various ocular diseases, including age-related macular degeneration (AMD). Tie2-expressing macrophages (TEMs) play crucial roles in angiogenesis. To investigate the role of TEMs and autophagy in the development of AMD, we employed macrophage-specific Tie2 knockout mice and used a laser-induced choroidal neovascularization (CNV). The results showed that TEMs can promote CNV formation by up-regulating the level of autophagy. These results were further verified by in vitro cell experiments that peritoneal macrophages from Tie2 knockout mice can inhibit the expression of autophagy-related factors and inhibit the expression of angiogenic factor of VEGF by activating AMPK signaling pathway. Our results suggest that TEMs and macrophage Tie2 signal mediated-autophagy play critical role in experimental CNV, and they may be novel preventive targets for AMD treatment.

The Suppression of Kallistatin on High-Glucose-Induced Proliferation of Retinal Endothelial Cells in Diabetic Retinopathy.

BACKGROUND: Diabetic retinopathy (DR) is a severe ocular complication of diabetes. Kallistatin has multiple biological functions including anti-inflammation and antiangiogenesis. Our aim was to detect the level of kallistatin in the vitreous of proliferative DR (PDR) and its effect on proliferation, migration, and tube formation of human retinal endothelial cells (HRECs) under high glucose in an in vitro model. METHODS: Vitreous humor samples were obtained through pars plana vitrectomy from 7 nondiabetic patients with idiopathic macular holes or idiopathic preretinal membranes and 10 PDR patients. The vitreous levels of kallistatin were measured by ELISA. HRECs were cultured with different concentrations of glucose and 1,000 nM kallistatin. The proliferation of HRECs was evaluated by a Cell Counting Kit-8 assay. Cell migration was assessed by using Transwell chambers. Cell sprouting was detected by tube formation assay. The RNA interference technique was used to create the knockdown of the kallistatin gene in HRECs for evaluating its effect on the proliferation, migration, and tube formation of HRECs. RESULTS: The vitreous levels of kallistatin were significantly lower in PDR patients in comparison with nondiabetic control patients (p < 0.05). Compared with 5 mM of normal glucose treatment, high glucose (30 mM) in culture significantly increased the proliferation and migration of HRECs, which was attenuated by 1,000 nM kallistatin. In addition, 1,000 nM kallistatin was shown to suppress high-glucose-induced tube formation and the expression of vascular endothelial growth factor of HRECs. Furthermore, the knockdown of kallistatin enhanced the proliferation, migration, and tube formation of HRECs. CONCLUSIONS: Our data indicated that kallistatin might be a potent inhibitory factor for PDR. The molecule plays its role by inhibiting high-glucose-induced proliferation of HRECs. The findings suggest that the upregulation of kallistatin might be an effective strategy for PDR prevention.

IL-37 Is a Novel Proangiogenic Factor of Developmental and Pathological Angiogenesis.

OBJECTIVE: Angiogenesis is tightly controlled by growth factors and cytokines in pathophysiological settings. Interleukin 37 (IL-37) is a newly identified cytokine of the IL-1 family, some members of which are important in inflammation and angiogenesis. However, the function of IL-37 in angiogenesis remains unknown. We aimed to explore the regulatory role of IL-37 in pathological and physiological angiogenesis. APPROACH AND RESULTS: We found that IL-37 was expressed and secreted in endothelial cells and upregulated under hypoxic conditions. IL-37 enhanced endothelial cell proliferation, capillary formation, migration, and vessel sprouting from aortic rings with potency comparable with that of vascular endothelial growth factor. IL-37 activates survival signals including extracellular signal-regulated kinase 1/2 and AKT in endothelial cells. IL-37 promoted vessel growth in implanted Matrigel plug in vivo in a dose-dependent manner with potency comparable with that of basic fibroblast growth factor. In the mouse model of retinal vascular development, neonatal mice administrated with IL-37 displayed increased neovascularization. We demonstrated further that IL-37 promoted pathological angiogenesis in the mouse model of oxygen-induced retinopathy. CONCLUSIONS: Our findings suggest that IL-37 is a novel and potent proangiogenic cytokine with essential role in pathophy siological settings.

Electrostatic nucleic acid nanoassembly enables hybridization chain reaction in living cells for ultrasensitive mRNA imaging.

Efficient approaches for intracellular delivery of nucleic acid reagents to achieve sensitive detection and regulation of gene and protein expressions are essential for chemistry and biology. We develop a novel electrostatic DNA nanoassembly that, for the first time, realizes hybridization chain reaction (HCR), a target-initiated alternating hybridization reaction between two hairpin probes, for signal amplification in living cells. The DNA nanoassembly has a designed structure with a core gold nanoparticle, a cationic peptide interlayer, and an electrostatically assembled outer layer of fluorophore-labeled hairpin DNA probes. It is shown to have high efficiency for cellular delivery of DNA probes via a unique endocytosis-independent mechanism that confers a significant advantage of overcoming endosomal entrapment. Moreover, electrostatic assembly of DNA probes enables target-initialized release of the probes from the nanoassembly via HCR. This intracellular HCR offers efficient signal amplification and enables ultrasensitive fluorescence activation imaging of mRNA expression with a picomolar detection limit. The results imply that the developed nanoassembly may provide an invaluable platform in low-abundance biomarker discovery and regulation for cell biology and theranostics.

Adrenomedullin22-52 suppresses high-glucose-induced migration, proliferation, and tube formation of human retinal endothelial cells.

PURPOSE: To investigate the roles of an adrenomedullin receptor antagonist (adrenomedullin(22-52)) on high-glucose-induced human retinal endothelial cell (HREC) in vitro cell biology. METHODS: HRECs were cultured with different concentrations of glucose and adrenomedullin(22-52). The proliferation of HRECs was evaluated by a cell counting kit-8 assay. Cell migration was assessed by scratch wound assay, and cell sprouting was detected by tube formation assay. The mRNA levels of adrenomedullin (ADM), vascular endothelial growth factor (VEGF), ADAMTS-1, and TSP-1 were measured by reverse-transcription polymerase chain reaction (RT-PCR). The VEGF and phosphatidylinositol 3' kinase (PI3K) pathway protein expression levels were assessed by western blot analysis. RESULTS: Compared with 5 mM normal glucose treatment, 30 mM glucose significantly promoted the migration of HRECs, which was attenuated by 1 µg/ml adrenomedullin(22-52). The proliferation of HRECs was also suppressed by 1 µg/ml adrenomedullin(22-52). Furthermore, compared with other groups, 5 µg/ml of adrenomedullin(22-52) was shown to suppress high-glucose-induced tube formation of HRECs. With adrenomedullin(22-52) treatment, the mRNA level of ADAMTS-1 was significantly increased. Moreover, western blot and RT-PCR analyses showed that HRECs treated with 30 mM glucose exhibited increased VEGF and PI3K pathway protein levels, while the expression levels were suppressed by 5 µg/ml of adrenomedullin(22-52). CONCLUSIONS: Our study indicated that adrenomedullin(22-52) mediated the migration, proliferation and tube formation after HRECs were exposed to high levels of glucose, which may be related to its ability to affect the expression of VEGF through the PI3K pathway.

[Inhibited experimental mouse corneal neovascularization by CCR3 antagonist].

OBJECTIVE: To explore the effect of CCR3 antagonist on the development of experimental corneal neovascularization. METHODS: Mouse corneas were burned by NaOH to induce corneal neovascularization.Fifty four clean male BABL/c mice aged 7-8 weeks were divided into control group, CCR3 antagonist group and VEGF antibody positive group according to randomized number table. The gene expression of CCR3 and its ligand eotaxin in burned corneas was examined by Real-time PCR. CCR3 antagonist was locally administrated after alkali injury and the formation of corneal neovascular 2 weeks after injury was examined using a digital camera linked to a slit lamp microscope and corneal whole mount staining with CD31. The mRNA and protein expression of chemokines in burned corneas was detected by Real-time PCR and western blot. RESULTS: Compared to control group, CCR3 antagonist treated mice resulted in significantly decreased corneal neovascularization. The related CNV area was 0.51 ± 0.03 in the CCR3 antagonist group, and that in the control group was 0.77 ± 0.15, with significant difference between them (t = 12.91, P = 0.00).Western blot detection did not show significant difference of VEGF protein expression between two groups.Expression level of VEGF in the CCR3 antagonist group was 0.91 ± 0.24, and that in the control group was 1.15 ± 0.30, showing no significant difference (t = 1.08, P = 0.34). CONCLUSIONS: Alkali-induced corneal neovascularization was inhibited by CCR3 antagonist. The mechanism that CCR3 pathway plays an important role in corneal neovascularization needs further exploration.

Incidence of Metamorphopsia After Successful Rhegmatogenous Retinal Detachment Surgery: A Systematic Review and Meta-Analysis.

PURPOSES: To investigate the incidence and factors influencing the occurrence of metamorphopsia in patients with simple rhegmatogenous retinal detachment (RRD) after surgery. METHODS: Relevant studies of metamorphopsia were identified by searching in PubMed, Embase, and Cochrane until August 2022. Meta-analysis of the incidence of metamorphopsia after rhegmatogenous retinal detachment surgery was performed using Review Manager 5.4 statistical software. RESULTS: A total of 12 studies reported 1133 participants with 469 patients with postoperative metamorphopsia. The meta-analysis showed a higher incidence of metamorphopsia in macular-off cases compared with macular-on RRD (RR = 2.88, 95% CI: 2.35 to 3.52). The use of perfluorocarbon liquid (PFCL) during pars plana vitrectomy (PPV) reduced the incidence of metamorphopsia (RR = 0.61, 95% CI: 0.41 to 0.92). There was no evidence of any important difference in metamorphopsia between participants in the PPV group and the scleral buckling (SB) group (RR = 1.04, 95% CI: 0.82 to 1.33). There was little or no difference in metamorphopsia between gas and silicon oil (SO) in the PPV group (RR = 0.89, 95% CI: 0.69 to 1.13). CONCLUSION: The incidence of postoperative metamorphopsia is higher in macular-off RRD, and PFCL should be a preferred choice to prevent postoperative metamorphopsia in macula-off RRD cases.

Potential Mechanism of Platelet GPIIb/IIIa and Fibrinogen on Retinal Vein Occlusion.

PURPOSE: To explore the role of coagulation and fibrinolytic factors, and the potential mechanism of platelet aggregation in the pathogenesis of retinal vein occlusion. METHODS: Coagulation and fibrinolytic parameters in patients with retinal vein occlusion were determined using hemagglutinin and HISCL-5000. Relationships between these elevated parameters and factors representing typical clinical manifestations of retinal vein occlusion were examined, and these parameters were analyzed using a STRING database to indicate the potential role of platelet aggregation. Platelet glycoprotein IIb/IIIa (GPIIb/IIIa) levels were evaluated by flow cytometry after antiplatelet treatment in patients and mouse models. Furthermore, the GPIIb/IIIa ligand fibrinogen in peripheral blood and retina of mouse models was assessed by the turbidimetric method and real-time PCR, respectively. RESULTS: In patients, significant increases in peripheral blood fibrinogen and GPIIb/IIIa levels were observed (p = 0.0040, p < 0.0001, respectively). A positive correlation was observed between macular thickness (MT) and both fibrinogen and GPIIb/IIIa (r = 0.4528, p = 0.0063; r = 0.3789, p = 0.0427, respectively). After intravitreal injections of anti-vascular endothelial growth factor drugs, a significant reduction in fibrinogen levels was observed (p = 0.0072). In addition, the use of antiplatelet drugs resulted in a significant decrease in GPIIb/IIIa (p < 0.0001). In a mouse model, antiplatelet therapy significantly reduced both peripheral blood and retina fibrinogen levels and the overall rate of vein occlusion 3 days after occlusion (p < 0.0005). In addition, the reduction in GPIIb/IIIa levels after antiplatelet therapy was remarkable. CONCLUSION: Fibrinogen and GPIIb/IIIa may be involved in retinal vein occlusion and blocking platelet aggregation may be a new therapeutic approach for retinal vein occlusion.

Trimethylamine N-oxide aggravates vascular permeability and endothelial cell dysfunction under diabetic condition: in vitro and in vivo study.

AIM: To provide the direct evidence for the crucial role of trimethylamine N-oxide (TMAO) in vascular permeability and endothelial cell dysfunction under diabetic condition. METHODS: The role of TMAO on the in vitro biological effect of human retinal microvascular endothelial cells (HRMEC) under high glucose conditions was tested by a cell counting kit, wound healing, a transwell and a tube formation assay. The inflammation-related gene expression affected by TMAO was tested by real-time polymerase chain reaction (RT-PCR). The expression of the cell junction was measured by Western blotting (WB) and immunofluorescence staining. In addition, two groups of rat models, diabetic and non-diabetic, were fed with normal or 0.1% TMAO for 16wk, and their plasma levels of TMAO, vascular endothelial growth factor (VEGF), interleukin (IL)-6 and tumor necrosis factor (TNF)-α were tested. The vascular permeability of rat retinas was measured using FITC-Dextran, and the expression of zonula occludens (ZO)-1 and claudin-5 in rat retinas was detected by WB or immunofluorescence staining. RESULTS: TMAO administration significantly increased the cell proliferation, migration, and tube formation of primary HRMEC either in normal or high-glucose conditions. RT-PCR showed elevated inflammation-related gene expression of HRMEC under TMAO stimulation, while WB or immunofluorescence staining indicated decreased cell junction ZO-1 and occludin expression after high-glucose and TMAO treatment. Diabetic rats showed higher plasma levels of TMAO as well as retinal vascular leakage, which were even higher in TMAO-feeding diabetic rats. Furthermore, TMAO administration increased the rat plasma levels of VEGF, IL-6 and TNF-α while decreasing the retinal expression levels of ZO-1 and claudin-5. CONCLUSION: TMAO enhances the proliferation, migration, and tube formation of HRMEC, as well as destroys their vascular integrity and tight connection. It also regulates the expression of VEGF, IL-6, and TNF-α.

Topical Administration of Bevacizumab to Facilitate the Functional Filtering Bleb After Trabeculectomy in the Rabbit.

Purpose: To evaluate the effects of bevacizumab in 3 different application methods, subconjunctival injection (SCI), hyaluronic acid retardant (HAR), and eye drop (ED), on attenuating scar formation in the filtering bleb. Methods: Trabeculectomy (TRAB) was performed on New Zealand rabbits. TRAB rabbits were intervened with bevacizumab SCI, HAR, ED, or mitomycin C, respectively. Intraocular pressure (IOP) of 1, 7, 14, and 28 days after TRAB was recorded, and the bleb survival rate was analyzed. Bleb height, area, and vascularization were evaluated using anterior segment optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) at 7, 14 and 28 days after surgery. A histopathology examination of the bleb tissue was performed. The expression levels of vascular endothelial growth factor (VEGF)-A, interleukin (IL)-1α, tumor necrosis factor-alpha (TNF-α), transforming growth factor-ß1 (TGF-ß1), and α-smooth muscle actin (α-SMA) were measured by Western blot. Results: Bevacizumab significantly reduced postoperative IOP and increased the survival of the filtering bleb, especially in the ED group. Less vascularization was shown in the SCI, HAR, and ED groups. Histopathological results showed the fewest levels of scarring and fibrosis in the ED group. The local VEGF-A, IL-1α, and TNF-α expression levels after bevacizumab ED were decreased, combined with suppression of TGF-ß1 and α-SMA. Conclusions: Postoperative use of bevacizumab EDs was an effective application method for improving surgical outcomes after TRAB in rabbits. It might be effective in preventing scarring of the filtering bleb by antivascularization and anti-inflammation.

Changing Trends in the Global Burden of Cataract Over the Past 30 Years: Retrospective Data Analysis of the Global Burden of Disease Study 2019.

BACKGROUND: Cataracts now account for the largest proportion of the global burden of blindness and vision loss. Understanding the changing trends in the global burden of cataracts over the past 30 years and the next 15 years is of clear significance for the prevention and control of cataracts in key populations. As far as we know, research on the future burden of cataracts is lacking. OBJECTIVE: This study aims to assess the global burden of cataracts over the past 30 years by using age-period-cohort modeling and to estimate trends in the next 15 years. METHODS: Data were obtained from the Global Burden of Disease Study 2019, the United Nations Development Programme, and the WHO (World Health Organization) Global Health Observatory data repository. The assessment of trends and disparities in the number and rate of disability-adjusted life years (DALYs) for cataracts from 1990 to 2019 was conducted. The association between the age-standardized DALY rate (ASDR) and the socio-demographic index (SDI), human development index (HDI), national levels of particulate matter <2.5 µm in diameter (PM2.5), and ambient ultraviolet radiation (UVR) was determined using linear regression analysis. Additionally, we used the Nordpred (Harald Fekjær and Bjørn Møller) age-period-cohort model to predict the cataract burden from 2020 to 2034. RESULTS: Globally, the number of DALYs due to cataract increased from 3,492,604 (95% uncertainty interval [UI] 2,481,846-4,719,629) in 1990 to 6,676,281 (95% UI 4,761,210-9,006,193) in 2019. The ASDRs due to cataract decreased from 93.17 (95% UI 66.14-125.32) in 1990 to 82.94 (95% UI 59.06-111.75) in 2019, with an average annual percentage change of -0.37 (95% CI -0.44 to -0.3; P<.001). Age, female sex, air pollution, smoking, high fasting plasma glucose levels, and a high body mass index were risk factors for the burden of cataracts. SDI and HDI were negatively correlated with ASDRs of cataracts, while PM2.5 and UVR were positively associated with them. Higher DALY rates were also associated with lower SDI (R2=0.1939; P<.001), lower HDI (R2=0.2828; P<.001), national PM2.5 concentration (R2=0.1874; P<.001), and ambient UVR levels (R2=0.2354; P<.001). The prediction model suggested that the number of DALYs due to cataract will continue to rise globally, while the cataract DALY rate will continue to decrease. CONCLUSIONS: While the ASDR of cataracts has decreased, there has been a notable increase in the number of DALYs over the past 30 years. Projections suggest that the global burden of cataracts will continue to rise over the next 15 years. To address this challenge, appropriate prevention and treatment policies must be implemented.

Burden of blindness and vision loss in China over the past 30 years: findings and predictions based on the Global Burden of Disease Study 2019.

AIMS: To investigate the burden of blindness and vision loss (BVL) in China over the past 30 years according to year, age and sex, and to estimate future predictions. METHODS: We analysed the years lived with disability (YLDs), number of cases, age-standardised YLD rates (ASYRs) and age-standardised prevalence rates (ASPRs) of BVL in China from 1990 to 2019. We focused on changes over time using estimated annual percentage changes (EAPCs). Additionally, we used the Bayesian age-period-cohort model to predict the BVL burden from 2020 to 2030. RESULTS: The number of YLDs and prevalent cases due to BVL increased from 2.57 (95% uncertainty interval (UI) 1.74 to 3.72) and 90.76 million (95% UI 72.21 to 111.92) in 1990 to 5.42 (95% UI 3.61 to 8.02) and 211.67 million (95% UI 168.21 to 259.66) in 2019, respectively. The BVL ASYRs and ASPRs showed a decreasing trend, with EAPCs of -0.13 (95% CI -0.28 to 0.02) and -0.11 (95% CI -0.19 to -0.04), respectively. The elderly and female populations had a higher BVL burden. The numbers of YLDs and cases due to BVL are projected to continue rising to 7.74 and 279.49 million in 2030, respectively. The ASYRs and ASPRs also showed increasing trends. CONCLUSION: While rates of BVL in China have decreased, there has been a notable increase in the number of YLDs and new cases over the past 30 years. Projections suggest that the burden of BVL will continue to rise over the next 11 years. To address this challenge, appropriate policies must be implemented.

ADP-ribosylation factor as a novel target for corneal neovascularization regression.

PURPOSE: To evaluate the roles of ADP-ribosylation factor (ARF) in alkali-induced corneal neovascularization (CNV). METHODS: CNV was induced by alkali injury and compared in ARF1 inhibitor- or vehicle-treated mice 3 weeks after injury. Angiogenic and apoptosis factor expression in corneas after injury was quantified with reverse-transcription PCR. Human retinal endothelial cell apoptosis induced by ARF1 inhibitor was detected with flow cytometry. RESULTS: The mRNA expression of ARF1 was augmented in the corneas after alkali injury. Compared with vehicle-treated mice, ARF1 inhibitor-treated mice exhibited impaired CNV 3 weeks after injury, as evidenced by corneal whole mount CD31-staining. Concomitantly, the enhancement of intraocular vascular endothelial growth factor expression was reduced in ARF1 inhibitor-treated mice compared to control mice after injury. Moreover, local administration of the ARF1 inhibitor after alkali injury enhanced intraocular caspase-3 expression. ARF1 inhibitor treatment can significantly induce human retinal endothelial cell apoptosis. CONCLUSIONS: The ARF1 inhibitor can induce the regression of alkali-induced CNV through increased endothelial cell apoptosis and downregulated intracorneal VEGF expression. ARF1 is an effective intervention target for CNV.

Association between Dietary Choline Intake and Diabetic Retinopathy: National Health and Nutrition Examination Survey 2005-2008.

PURPOSE: To explore whether there is an association between dietary choline intake and odds of diabetic retinopathy (DR) in the US diabetic population. METHODS: A cross-sectional study was conducted using the combined data of the National Health and Nutrition Examination Survey (NHANES) 2005-2008 of a complex, multistage, and probability-sampling design. Energy-adjusted choline intake was calculated separately for men and women using the residual method. Binary logistic regression adjusting for covariates was used to identify the variables associated with DR. RESULTS: We included 644 male and 628 female diabetic subjects, which were equivalent to a weighted survey sample of 9,339,124 for males and 10,109,553 for females respectively. Female DR patients consumed more choline than non-DR patients (268.6 mg/d vs 250.9 mg/d; p = .046). The estimated prevalence of DR was 17.4%, 21.9%, and 29.7% across three levels of dietary choline intake in females, respectively. In multivariable logistic-regression models, the odds ratio (OR) of DR for female patients in the highest choline intake group was 2.14 (95% confidence interval [CI], 1.38-3.31; p = .001) compared with those in the lowest intake group. This association was positive but not statistically significant in males. CONCLUSION: Higher intake of dietary choline is associated with increased odds of DR in females, but not in males. Further studies are warranted to investigate the direct role of choline in DR development and determine the recommended daily intake of choline for diabetic patients weighing the pros and cons of dietary choline consumption.

SDF­1α/CXCR4 signaling promotes capillary tube formation of human retinal vascular endothelial cells by activating ERK1/2 and PI3K pathways in vitro.

The purpose of this study is to address the effect and mechanism of stromal cell­derived factor­1 (SDF­1)α/chemokine (C­X­C motif) receptor 4 (CXCR4) signaling on capillary tube formation of human retinal vascular endothelial cells (HRECs). The expression of CXCR4 in HRECs was quantified by reverse transcription (RT­PCR) and western blotting. The effects of SDF­1α/CXCR4 signaling in capillary tube formation and migration of HRECs was examined using three­dimensional Matrigel assay and wound scratching assay respectively in vitro. Cell proliferation of HRECs was examined using cell counting kit (CCK)­8 assay in the presence of different concentrations of SDF­1α protein. The effect of SDF­1α/CXCR4 signaling in HREC expression of VEGF, basic fibroblast growth factor (bFGF), IL­8 and intercellular cell adhesion molecule (ICAM)­1 was examined using RT­PCR and western blotting. RT­PCR and western blot analysis revealed CXCR4 was expressed in HRECs. The number of intact capillary tubes formed by HRECs in the presence of SDF­1α was markedly more compared with a PBS treated control group. However, it was reduced with treatment with an CXCR4 antagonist. Wound scratching assay showed a significant increase in the number of migrated HRECs under SDF­1α stimulation and the number was reduced with treatment with an CXCR4 antagonist. RT­PCR and western blotting showed that SDF­1α significantly promoted VEGF, bFGF, IL­8 and ICAM­1 expression in HRECs. The proliferation of HRECs in the presence of SDF­1α was promoted in a dosage­dependent manner. SDF­1α/CXCR4 signaling can increase HREC capillary tube formation through promoting HREC migration, proliferation and expression of VEGF, bFGF, IL­8 and ICAM­1.

Critical role of SDF-1α-induced progenitor cell recruitment and macrophage VEGF production in the experimental corneal neovascularization.

PURPOSE: To address the roles of the stromal derived factor-1 (SDF-1) α in the course of experimental corneal neovascularization (CNV). METHODS: CNV was induced by alkali injury and compared in SDF-1α- or vehicle-treated mice two weeks after injury. Angiogenic factor expression in the early phase after injury was quantified by reverse transcription polymerase chain reaction (RT-PCR). Progenitor cell, macrophage, and monocyte intracorneal accumulation in the early phase after injury was evaluated by flow cytometric analysis. RESULTS: The mRNA expression of SDF-1α was augmented, together with infiltration of c-kit-positive progenitor cells in the corneas after the alkali injury. Compared with vehicle-treated mice, SDF-1α-treated mice exhibited enhanced CNV two weeks after injury, as evidenced by enlarged cluster of differentiation 31 (CD31)-positive areas. Concomitantly, the intracorneal infiltration of c-kit-positive progenitor cells but not F4/80+ macrophages or Ly-6G+ monocytes was significantly enhanced in SDF-1α-treated mice compared to vehicle-treated mice. SDF-1α enhanced vascular endothelial growth factor (VEGF) expression by murine peritoneal macrophages. Enhancement in intraocular VEGF expression was greater in SDF-1α-treated mice than in control mice after injury. Moreover, local administration of C-X-C chemokine receptor type 4 (CXCR4) antagonist after alkali injury reduced alkali-induced CNV. CONCLUSIONS: SDF-1α-treated mice exhibited enhanced alkali-induced CNV through enhanced intracorneal progenitor cell infiltration and increased VEGF expression by macrophages.

Assessing the protective effects of cryptotanshinone on CoCl2­induced hypoxia in RPE cells.

The development of several retinal diseases is closely related to hypoxia. As a component of the Traditional Chinese medicine Salvia miltiorrhiza, the effects of cryptotanshinone (CT) on retinal cells under hypoxic conditions are not well understood. The aim of the present study was to explore how CT exerted its protective effects on retinal pigment epithelium (RPE) cells under hypoxic conditions induced by cobalt chloride (CoCl2). The effects of CT were investigated using a Cell Counting Kit­8 assay, Annexin V­FITC/PI staining, reverse transcription­quantitative PCR and western blotting in ARPE­19 cells. CT (10 and 20 µM) reduced the CoCl2­induced increase in vascular endothelial growth factor expression and hypoxia­inducible transcription factor­1α expression in ARPE­19 cells. Additionally, CT alleviated hypoxia­induced apoptosis by regulating Bcl­2 and Bax protein expression. CT treatment also reduced the increase in the mRNA levels of IL­6, IL­1ß and TNF­α induced by CoCl2. In summary, CT may protect RPE cells against apoptosis and inflammation in CoCl2­induced hypoxia, and these results warrant further in vivo study into its value as a drug for treating hypoxic eye diseases.

Inhibition of PDGF-BB reduces alkali-induced corneal neovascularization in mice.

The aim of the present study was to investigate the role of platelet­derived growth factor (PDGF)­BB/PDGF receptor (R)­ß signaling in an experimental murine corneal neovascularization (CrNV) model. Experimental CrNV was induced by alkali injury. The intra­corneal expression of PDGF­BB was examined using immunohistochemistry. The effect of PDGF­BB on CrNV was evaluated using immunofluorescence staining. The expression levels of PDGFR­ß in human retinal endothelial cells (HRECs) under normal conditions or following cobalt chloride treatment, which induced hypoxic conditions, was assessed using reverse transcription­quantitative PCR. The effect of exogenous treatment of PDGF­BB on the proliferation, migration and tube formation of HRECs under normoxic or hypoxic conditions was evaluated in vitro using Cell Counting Kit­8, wound healing and 3D Matrigel capillary tube formation assays, respectively. The results indicated that the intra­corneal expression levels of the proteins of PDGF­BB and PDGFR­ß were detectable on days 2 and 7 following alkali injury. The treatment with neutralizing anti­PDGF­BB antibody resulted in significant inhibition of CrNV. The intra­corneal expression levels of vascular endothelial growth factor A, matrix metallopeptidase (MMP)­2 and MMP­9 proteins were downregulated, while the expression levels of thrombospondin (TSP)­1, TSP­2, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)­1 and ADAMTS­2 were upregulated significantly in mice treated with anti­PDGF­BB antibody. The expression levels of PDGFR­ß were upregulated in HRECs under hypoxic conditions compared with those noted under normoxic conditions. Recombinant human PDGF­BB promoted the proliferation, migration and tube formation of HRECs under hypoxic conditions. The data indicated that PDGF­BB/PDGFR­ß signaling was involved in CrNV and that it promoted endothelial cell proliferation, migration and tube formation. The pro­angiogenic effects of this pathway may be mediated via the induction of pro­angiogenic cytokine secretion and the suppression of anti­angiogenic cytokine secretion.

Elevated plasma trimethylamine-N-oxide levels are associated with diabetic retinopathy.

AIMS: To determine the relationship between plasma levels of trimethylamine-N-oxide (TMAO) and odds of diabetic retinopathy (DR). METHODS: A cross-sectional study was conducted. Blood samples were obtained from 122 type 2 diabetes mellitus (T2DM) patients with or without DR. Multivariable logistic regression analyses were performed to identify the association between plasma TMAO and DR. The diagnostic value of plasma TMAO was assessed by the area under the receiver operating characteristic curve (AUROC) and integrated discrimination improvement (IDI). RESULTS: In the T2DM patients, plasma levels of TMAO were significantly higher in patients with DR compared with those without DR (P = 0.001). As logarithmic (ln) transformation of TMAO increased per standard deviation (SD), there was higher probability to have DR [odds ratio (OR) = 2.31; P = 0.005]. As ln-transformed TMAO increased per SD, the severity of DR was more likely to get worse (OR = 2.05; P = 0.004). In the diagnostic model, the addition of TMAO contributed to the improvement in AUROC from 0.646 to 0.734 (P = 0.043), and the IDI was 10.7% (P < 0.001). CONCLUSION: Elevated levels of plasma TMAO were associated with higher odds and worse severity of DR in T2DM patients, and further investigation is required for the causality of this association.