Yujing Bai

Biodegradable CaMgZn bulk metallic glass for potential skeletal application.

A low density and high strength alloy, Ca65Mg15Zn20 bulk metallic glass (CaMgZn BMG), was evaluated by both in vitro tests on ion release and cytotoxicity and in vivo implantation, aimed at exploring the feasibility of this new biodegradable metallic material for potential skeletal applications. MTT assay results showed that the experimental CaMgZn BMG extracts had no detectable cytotoxic effects on L929, VSMC and ECV304 cells over a wide range of concentrations (0-50%), whereas for MG63 cells concentrations in the range ~5-20% promoted cell viability. Meanwhile, alkaline phosphatase (ALP) activity results showed that CaMgZn BMG extracts increased alkaline phosphatase (ALP) production by MG63 cells. However, Annexin V-fluorescein isothiocyanate and propidium iodide staining indicated that higher concentrations (50%) might induce cell apoptosis. The fluorescence observation of F-actin and nuclei in MG63 cells showed that cells incubated with lower concentrations (0-50%) displayed no significant change in morphology compared with a negative control. Tumor necrosis factor-α expression by Raw264.7 cells in the presence of CaMgZn BMG extract was significantly lower than that of the positive and negative controls. Animal tests proved that there was no obvious inflammation reaction at the implantation site and CaMgZn BMG implants did not result in animal death. The cortical thickness around the CaMgZn BMG implant increased gradually from 1 to 4 weeks, as measured by in vivo micro-computer tomography.

Retinal ischemia/reperfusion injury is mediated by Toll-like receptor 4 activation of NLRP3 inflammasomes.

PURPOSE Retinal ischemia/reperfusion (IR) is common in eye disorders. Pattern-recognition receptors (PRRs) are reported to initiate sterile inflammatory response. The role of PRRs in retinal IR injury is currently unknown. Thus, we investigated the expression and function of membrane and cytoplasmic PRRs during retinal IR. METHODS Retinal IR was induced in adult Brown Norway rats by clipping the retinal vessels for 30 minutes. RNA and proteins were extracted during the course of reperfusion, and the expression levels of the following proteins were determined: Toll-like receptor 2 (TLR2), TLR4, myeloid differentiation factor 88 (MyD88), TNF receptor-associated factor 6 (TRAF6), nuclear factor-κB (NF-κB), nucleotide-binding oligomerization domain-like receptor with pyrin domain protein 1 (NLRP1), NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, IL-1β, and IL-18. TLR4 expression in the retina was studied using immunohistochemistry. In addition, a TLR4 inhibitor was injected into the vitreous body as a therapeutic agent. After the treatment of TLR4 inhibitors, the levels of the above factors were evaluated, the apoptosis of cells in the retina, expression of cleaved-caspase-3 (c-casp-3), death of retinal ganglion cells, and the retina electroretinography was assessed. RESULTS After releasing the artery clamp, the retinal vessels were reperfused in 5 minutes. During the reperfusion, TLR4, MyD88, TRAF6, NF-κB, NLRP1, NLRP3, mature IL-1β, and IL-18 were upregulated, but not TLR2. In the IR model, TLR4 was highly expressed in ganglion cell and glia cell. Additionally, the inhibition of TLR4 significantly downregulated the activation of NLRP3, but not NLRP1, and the secretion of mature IL-1β and IL-18 also were inhibited. Moreover, the TLR4 inhibitor partially attenuated the injury of the retina, including alleviated retina apoptosis, downregulated c-casp-3 expression, rescued retinal ganglion cells death, and restored retina function. CONCLUSIONS These findings suggest that TLR4-signaling activation, triggered by damage-associated molecular patterns, regulates the activation of the NLRP3 inflammasomes and is responsible for the function of the retina in retinal IR injury.

Polyethylene glycol modified pigment epithelial-derived factor: new prospects for treatment of retinal neovascularization

Pathological retinal neovascularization and choroidal neovascularization are major causes of vision loss in a variety of clinical conditions, such as retinopathy of prematurity, age-related macular degeneration, and diabetic retinopathy. Pigment epithelial-derived factor (PEDF) has been found to be the most potent natural, endogenous inhibitor of neovascularization, but its application is restricted because of its instability and short half-life. Polyethylene glycol (PEG) has been used as a drug carrier to slow clearance rate for decades. The present study investigated PEGylated-PEDF for the first time and evaluated its long-term effects on preventing angiogenesis in vitro and in vivo. PEG showed lower cytotoxicity to human umbilical vein endothelial cells (HUVECs). In vitro, PEGylated-PEDF inhibited HUVEC proliferation, migration, tube formation, and vascular endothelium growth factor secretion and induced HUVEC apoptosis in a dose-dependent manner, and it showed a statistically significant difference compared with the PEDF treatment group. In vivo, PEGylated-PEDF had a long-lasting effect in both plasma and retinal concentrations. In an oxygen-induced retinopathy model, one intravitreous injection of PEGylated-PEDF after mouse pups were moved into room air resulted in a significant difference in the inhibition of retinal neovascularization, which decreased the nonperfusion area, compared with the PEDF-treated group. Our present study demonstrated for the first time the long-term inhibitory effects of PEGylated-PEDF on the prevention of neovascularization in vitro and in vivo. These data suggest that PEGylated-PEDF could offer an innovative therapeutic strategy for preventing retinal neovascularization.

Antiangiogenesis Effects of Endostatin in Retinal Neovascularization

PURPOSE Pathological retinal angiogenesis is a major cause of vision loss. Endostatin is a natural antiangiogenesis antitumor protein that is widely used in cancer studies. In this study, we investigated the efficacy and potential mechanisms of endostatin for the prevention of retinal neovascularization both in vitro and in vivo. METHODS Human umbilical vein endothelial cells (HUVECs) were used for the in vitro studies. HUVECs were incubated with endostatin or the vascular endothelial growth factor (VEGF) and endostatin for different time points. Cell proliferation, migration, cell cycling, and tube formation studies were carried out using a Cell Counting Kit-8 assay, a Transwell assay, flow cytometry, and a Matrigel assay, respectively. Enzyme-Linked Immunosorbent Assay (ELISA) was used to study VEGF and pigment epithelial-derived factor (PEDF) protein secretion from the HUVECs at different time points. A murine oxygen-induced retinopathy (OIR) model was used for the in vivo studies. Seven-day-old C57BL/6J pups (p7) were exposed to 75% oxygen for 5 days. On p12, the animals were returned to a normal atmosphere and were immediately injected intravitreously with 1.5 μL of a 5 mg/mL endostatin solution. At p18, the mice were perfused with fluorescein-dextran-FITC, and their retinas were flat mounted to measure the nonperfused area. Retinal VEGF and PEDF levels were also measured by ELISA Kits in the OIR mice at p18. RESULTS In vitro, endostatin inhibited HUVEC proliferation in a dose-dependent manner and also inhibited HUVEC proliferation in a VEGF-containing medium. Additionally, endostatin can inhibit migration, tube formation, and VEGF secretion in HUVECs, while also inducing apoptosis in HUVECs at several time points. These effects were statistically significant when compared to the control group (P<0.05). In vivo, a single intravitreous injection of endostatin reduced the retinal nonperfused area from 30% in the control group to 23% in the treatment group (P<0.0001). Intravitrous injection of endostatin reduced VEGF levels in retinas, while it increased PEDF levels. CONCLUSIONS Endostatin showed convincing inhibitory effects on angiogenesis both in vitro and in vivo. The inhibitory effects may be, at least partly, resulted from the restoration of the PEDF/VEGF ratio. These data suggest that endostatin could offer an innovative pharmaceutical strategy for the prevention of retinal neovascularization.

Whole-exome sequencing implicates UBE3D in age-related macular degeneration in East Asian populations.

Age-related macular degeneration (AMD) is a leading cause of irreversible central blindness among the elderly worldwide. We use exome sequencing to analyse nonsynonymous single-nucleotide variants (SNVs) across the whole genome of 216 neovascular AMD cases and 1,553 controls. As a follow-up validation, we evaluate 3,772 neovascular AMD cases and 6,942 controls from five independent cohorts in the East Asian population. Here we show strong evidence of an association at a novel, missense SNV, rs7739323, which is located in the ubiquitin protein ligase E3D (UBE3D) gene (Pmeta=1.46 × 10(-9), odds ratio (OR)=0.74, 95% confidence interval (CI): 0.63-0.88). Furthermore, ablation of the UBE3D protein lead to an abnormal amount of pigment granules deposited in retinal pigment epithelium microvilli area and an abnormal response on electroretinography (ERG) in UBE3D(+/-) heterozygous mice. Our findings indicate that the ubiquitin-proteasome system may play a role in the pathogenesis of neovascular AMD.

In vitro and in vivo evaluation of SLA titanium surfaces with further alkali or hydrogen peroxide and heat treatment.

The present study aimed to evaluate the bioactivity of titanium surfaces sandblasted with large-grit corundum and acid etched (SLA) plus further alkali or hydrogen peroxide and heat treatment for dental implant application. Pure titanium disks were mechanically polished as control surface (Ti-control) and then sandblasted with large-grit corundum and acid etched (SLA). Further chemical modifications were conducted using alkali and heat treatment (ASLA) and hydrogen peroxide and heat treatment (HSLA) alternatively. The surface properties were characterized by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and contact angle and roughness measurements. Further evaluation of surface bioactivity was conducted by MC3T3-E1 cell attachment, proliferation, morphology, alkaline phosphatase (ALP) activity and calcium deposition on the sample surfaces. After insertion in the beagles mandibula for a specific period, cylindrical implant samples underwent micro-CT examination and then histological examination. It was found that ASLA and HSLA surfaces significantly increased the surface wettability and MC3T3-E1 cell attachment percentage, ALP activity and the quality of calcium deposition in comparison with simple SLA and Ti-control surfaces. Animal studies showed good osseointegration of ASLA and HSLA surfaces with host bone. In conclusion, ASLA and HSLA surfaces enhanced the bioactivity of the traditional SLA surface by integrating the advantages of surface topography, composition and wettability.

Interleukin-1β Level Is Increased in Vitreous of Patients with Neovascular Age-Related Macular Degeneration (nAMD) and Polypoidal Choroidal Vasculopathy (PCV).

Purpose To examine the expression of pro-interleukin-1β (pro-IL-1β) and interleukin-1β (IL-1β) in the vitreous body of patients with neovascular age-related macular degeneration(nAMD), polypoidal choroidal vasculopathy (PCV), proliferative diabetic retinopathy (PDR), retinal vein occlusion (RVO) or Eales’ disease to further elucidate the role of IL-1β and inflammation in the pathogenesis of neovascular retinal disease. Design Prospective clinical laboratory investigation study. Methods All patients enrolled had vitreous hemorrhage due to nAMD, PCV, PDR, RVO or Eales’ disease that required vitrectomy. Patients were excluded for any history of active intraocular inflammation, or other ophthalmic surgery besides vitrectomy. Control samples were obtained from patients with idiopathic macular epiretinal membrane. A total of fifty vitreous samples were collected from patient during vitrectomy. Pro-IL-1β and IL-1β expression were measured by enzyme-linked immunosorbent assay (ELISA). Results were analyzed statistically using nonparametric tests. Results Expression of pro-IL-1β protein was increased by 2.83-fold and 9.19-fold in PCV and nAMD vitreous samples relative to control, respectively. Expression of IL-β protein was increased by 10-fold and 4.83-fold in PCV and nAMD vitreous samples relative to control, respectively. Conclusions Our results demonstrate that expression of pro-IL-1β and IL-1β proteins is higher in PCV and nAMD. The roles of pro-IL-1β and IL-1β as inflammatory mediators in the development of PCV and nAMD may be associated with photoreceptor degeneration and neovascularization which necessitates further study.

Quercetin Inhibits Vascular Endothelial Growth Factor-Induced Choroidal and Retinal Angiogenesis in vitro

Purpose: The aim of this study was to investigate the effects of quercetin on vascular endothelial growth factor (VEGF)-induced choroidal and retinal angiogenesis in vitro using a rhesus macaque choroid-retinal endothelial (RF/6A) cell line. Methods: RF/6A cells were cultured in Dulbeccos modified Eagles medium containing 10% fetal bovine serum. Then the cells were treated with different concentrations (from 0 to 100 μM) of quercetin and 100 ng/ml VEGF. The cell proliferation was assessed using cholecystokinin octapeptide dye. The cell migration was investigated by a Transwell assay. The tube formation was measured on Matrigel. Furthermore, the impact of quercetins effects on VEGF-induced activation of VEGF receptor 2 (VEGFR-2) downstream signal pathways was tested by Western blot analysis. Results: Quercetin inhibits RF/6A cell proliferation in a dose-dependent fashion: 22.7, 31.5 and 36.7% inhibition on treatment with 10, 50 and 100 μM quercetin, respectively. VEGF-induced migration and tube formation of RF/6A cells were also significantly inhibited by quercetin in a dose-dependent manner. Quercetin inhibits VEGF-induced VEGFR-2 downstream signal pathways of RF/6A. Conclusions: The results show that quercetin inhibits VEGF-induced cell proliferation, migration and tube formation of RF/6A. We suggest that quercetin inhibits VEGF-induced choroidal and retinal angiogenesis in vitro. Collectively, the findings in the present study suggest that quercetin inhibits VEGF-induced choroidal and retinal angiogenesis by targeting the VEGFR-2 pathway. This suggests that quercetin is a choroidal and retinal angiogenesis inhibitor.

Slit2 Promotes Angiogenic Activity Via the Robo1-VEGFR2-ERK1/2 Pathway in Both In Vivo and In Vitro Studies.

PURPOSE Recent research has provided novel but contrary insight into the function of Slit2-Robo signaling in angiogenesis. Although the role of Robo in choroidal neovascularization (CNV) has been studied, the effect of its ligand, Slit2, on CNV development is unclear. This study investigated the role of endogenous Slit2 in CNV and the possible mechanisms. METHODS Laser-induced CNV in Slit2 transgenic and wild-type mice was used to study the effects of endogenous Slit2 on angiogenesis in vivo. Fluorescein angiography was performed to evaluate the leakage area of each lesion. Plasmid-based gene transfer technology was used to increase Slit2 expression and to study its effects on human umbilical vein endothelial cells (HUVECs) in vitro. Cell proliferation, migration, and tube formation were assessed. Quantitative real-time PCR and Western blot were used to measure expression in the extracellular signal-related kinase 1/2 (ERK1/2), protein kinase B (AKT), and p38 mitogen-activated protein kinase (p38 MAPK) molecular pathways. RESULTS Laser treatment led to more CNV and vascular leakage in Slit2 transgenic mice compared with wild-type mice. Upregulation of Slit2, Robo1, VEGF receptor 2 (VEGFR2), and phosphorylated ERK1/2 (p-ERK1/2) were detected in retina and choroidal tissue of laser-treated transgenic mice. After transfection of HUVECs with a Slit2 overexpression plasmid, cell proliferation, migration, and tube formation capacities were promoted. Slit2, Robo1, VEGFR2, and p-ERK1/2 were elevated in transfected HUVECs. CONCLUSION Slit2 overexpression promoted angiogenic effects in both a laser-induced CNV mouse model and HUVECs and promoted the biological activity of endothelial cells. Slit2 may promote angiogenesis by upregulating Robo1 and activating the VEGFR2-ERK1/2 pathway.

Different Hereditary Contribution of the CFH Gene Between Polypoidal Choroidal Vasculopathy and Age-Related Macular Degeneration in Chinese Han People

PURPOSE To investigate whether 11 variants in complement factor H gene contributed differently in patients with neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) of Chinese descent. METHODS We performed a case-control study in a group of Chinese patients with nAMD (n = 344) or PCV (n = 368) and contrasted the results against an independent control group comprising 511 mild cataract patients without any evidence of age-related maculopathy. Association analysis of allele and genotype frequencies was performed for 11 haplotype-tagging single-nucleotide polymorphisms (SNPs) at the CFH locus (rs1061170, rs1329428, rs1410996, rs2284664, rs375396, rs529825, rs551397, rs7540032, rs800292, rs2274700, and rs1065489). Multinomial logistic regression analyses were performed to estimate and compare the effect of these 11 CFH polymorphisms on AMD and PCV, using the wild-type genotype as reference. Differences in the observed genotypic distributions between cases and controls were tested by using χ(2) tests, with age and sex adjusted for using logistic regression. RESULTS CFH rs1065489 was not significantly associated with the nAMD phenotype in Chinese collections either on univariate or multivariate analysis (P > 0.05 for all comparisons). The other 10 SNPs of CFH were significantly associated with the nAMD phenotype. As for PCV, all 11 SNP markers were significantly associated with risk of PCV before or after correction for age and sex differences. Eight of the 11 SNP markers showed significant evidence of heterogeneity between AMD and PCV (P < 0.05 for all comparisons). CONCLUSIONS Our data suggest that the genetic architecture at the CFH locus is complex with some markers showing significant skewing of the genotypes toward nAMD or PCV in Asians. This further supports the clinical observation that nAMD and PCV could have distinct pathogenesis mechanisms, which will require larger studies to accurately dissect.