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Yuqing Lan - One of the best experts on this subject based on the ideXlab platform.

  • downregulation of vegf mrna expression by triamcinolone acetonide acetate loaded chitosan derivative nanoparticles in human Retinal Pigment epithelial cells
    International Journal of Nanomedicine, 2012
    Co-Authors: Huaisheng Zhou, Liqun Yang, Haijun Gong, Liangzheng Cheng, Haisheng Zheng, Liming Zhang, Yuqing Lan
    Abstract:

    Background The purpose of this study was to investigate the downregulation of mRNA expression of vascular endothelial growth factor (VEGF) by triamcinolone acetonide acetate (TAA)-loaded chitosan nanoparticles in human Retinal Pigment epithelial cells. Methods TAA-loaded deoxycholic acid-modified chitosan (TAA/DA-Chit) nanoparticles were prepared via a self-assembly mechanism, and their morphology and zeta potential were examined by transmission electron microscopy and zeta potential analysis, respectively. DA-Chit and TAA/DA-Chit nanoparticle toxicity was evaluated using a Cell Counting Kit-8 assay. The efficiency of cellular uptake was determined using fluorescein isothiocyanate-labeled DA-Chit nanoparticles, in place of TAA/DA-Chit nanoparticles, assessed by both inverted fluorescence microscopy and flow cytometry. Downregulation of VEGF mRNA expression by TAA/DA-Chit nanoparticles was further investigated by real-time reverse transcription polymerase chain reaction (RT-PCR) assay of the treated human Retinal Pigment epithelial cells. Results TAA/DA-Chit nanoparticles were prepared with a TAA-loading capacity in the range of 12%-82%, which increased the water solubility of TAA from 0.3 mg/mL to 2.1 mg/mL. These nanoparticles showed oblate shapes 100-550 nm in size in transmission electron microscopic images and had positive zeta potentials. The Cell Counting Kit-8 assay indicated that the DA-Chit and TAA/DA-Chit nanoparticles had no toxicity and low toxicity, respectively, to human Retinal Pigment epithelial cells. Fluorescein isothiocyanate-labeled DA-Chit nanoparticle uptake by human Retinal Pigment epithelial cells was confirmed by inverted fluorescence microscopy and flow cytometry. Real-time RT-PCR assay showed that the VEGF mRNA level decreased after incubation of human Retinal Pigment epithelial cells with TAA/DA-Chit nanoparticles. Conclusion TAA/DA-Chit nanoparticles had a downregulating effect on VEGF mRNA expression in human Retinal Pigment epithelial cells and low cytotoxicity, which might be beneficial characteristics for the development of future treatment for diabetic retinopathy.

Huaisheng Zhou - One of the best experts on this subject based on the ideXlab platform.

  • downregulation of vegf mrna expression by triamcinolone acetonide acetate loaded chitosan derivative nanoparticles in human Retinal Pigment epithelial cells
    International Journal of Nanomedicine, 2012
    Co-Authors: Huaisheng Zhou, Liqun Yang, Haijun Gong, Liangzheng Cheng, Haisheng Zheng, Liming Zhang, Yuqing Lan
    Abstract:

    Background The purpose of this study was to investigate the downregulation of mRNA expression of vascular endothelial growth factor (VEGF) by triamcinolone acetonide acetate (TAA)-loaded chitosan nanoparticles in human Retinal Pigment epithelial cells. Methods TAA-loaded deoxycholic acid-modified chitosan (TAA/DA-Chit) nanoparticles were prepared via a self-assembly mechanism, and their morphology and zeta potential were examined by transmission electron microscopy and zeta potential analysis, respectively. DA-Chit and TAA/DA-Chit nanoparticle toxicity was evaluated using a Cell Counting Kit-8 assay. The efficiency of cellular uptake was determined using fluorescein isothiocyanate-labeled DA-Chit nanoparticles, in place of TAA/DA-Chit nanoparticles, assessed by both inverted fluorescence microscopy and flow cytometry. Downregulation of VEGF mRNA expression by TAA/DA-Chit nanoparticles was further investigated by real-time reverse transcription polymerase chain reaction (RT-PCR) assay of the treated human Retinal Pigment epithelial cells. Results TAA/DA-Chit nanoparticles were prepared with a TAA-loading capacity in the range of 12%-82%, which increased the water solubility of TAA from 0.3 mg/mL to 2.1 mg/mL. These nanoparticles showed oblate shapes 100-550 nm in size in transmission electron microscopic images and had positive zeta potentials. The Cell Counting Kit-8 assay indicated that the DA-Chit and TAA/DA-Chit nanoparticles had no toxicity and low toxicity, respectively, to human Retinal Pigment epithelial cells. Fluorescein isothiocyanate-labeled DA-Chit nanoparticle uptake by human Retinal Pigment epithelial cells was confirmed by inverted fluorescence microscopy and flow cytometry. Real-time RT-PCR assay showed that the VEGF mRNA level decreased after incubation of human Retinal Pigment epithelial cells with TAA/DA-Chit nanoparticles. Conclusion TAA/DA-Chit nanoparticles had a downregulating effect on VEGF mRNA expression in human Retinal Pigment epithelial cells and low cytotoxicity, which might be beneficial characteristics for the development of future treatment for diabetic retinopathy.

Faik Gelisken - One of the best experts on this subject based on the ideXlab platform.

Anthony P Adamis - One of the best experts on this subject based on the ideXlab platform.

  • intrachoroidal neovascularization in transgenic mice overexpressing vascular endothelial growth factor in the Retinal Pigment epithelium
    American Journal of Pathology, 2001
    Co-Authors: Catherine Schwesinger, Richard M Rohan, Tobias N Meyer, Joseph J K, Michael T Redmond, Vassiliki Poulaki, Antonia M. Joussen, Antonio Fernandez, Anthony P Adamis
    Abstract:

    Choroidal neovascularization in age-related macular degeneration is a frequent and poorly treatable cause of vision loss in elderly Caucasians. This choroidal neovascularization has been associated with the expression of vascular endothelial growth factor (VEGF). In current animal models choroidal neovascularization is induced by subRetinal injection of growth factors or vectors encoding growth factors such as VEGF, or by disruption of the Bruch’s membrane/Retinal Pigment epithelium complex with laser treatment. We wished to establish a transgenic murine model of age-related macular degeneration, in which the overexpression of VEGF by the Retinal Pigment epithelium induces choroidal neovascularization. A construct consisting of a tissue-specific murine Retinal Pigment epithelium promoter (RPE65 promoter) coupled to murine VEGF164 cDNA with a rabbit β-globin-3′ UTR was introduced into the genome of albino mice. Transgene mRNA was expressed in the Retinal Pigment epithelium at all ages peaking at 4 months. The expression of VEGF protein was increased in both the Retinal Pigment epithelium and choroid. An increase of intravascular adherent leukocytes and vessel leakage was observed. Histopathology revealed intrachoroidal neovascularization that did not penetrate through an intact Bruch’s membrane. These results support the hypothesis that additional insults to the integrity of Bruch’s membrane are required to induce growth of choroidal vessels into the subRetinal space as seen in age-related macular degeneration. This model may be useful to screen for inhibitors of choroidal vessel growth.

  • synthesis and secretion of vascular permeability factor vascular endothelial growth factor by human Retinal Pigment epithelial cells
    Biochemical and Biophysical Research Communications, 1993
    Co-Authors: Anthony P Adamis, Lawrence F. Brown, Brygida Berse, David T Shima, Kiangteck J Yeo, Tetkin Yeo, Patricia A Damore, Judah Folkman
    Abstract:

    The presence of the secreted angiogenic molecule, vascular permeability factor/vascular endothelial growth factor, was investigated in human Retinal Pigment epithelial cells. Northern and in situ hybridization analysis of cultured cells identified vascular permeability factor/vascular endothelial growth factor mRNA. Western analysis of cell lysates identified a 42 kD protein that comigrated with human recombinant vascular permeability factor/vascular endothelial growth factor. Immunoassay measurements detected vascular permeability factor/vascular endothelial growth factor protein in cell lysates and conditioned media in vitro and in cell lysates isolated directly from post-mortem eyes. These data demonstrate that human Retinal Pigment epithelial cells can synthesize the secreted angiogenic peptide vascular permeability factor/vascular endothelial growth factor in vitro and in situ. The production and secretion of this factor by human Retinal Pigment epithelial cells may be important in the pathogenesis of ocular neovascularization.

Richard S Kaiser - One of the best experts on this subject based on the ideXlab platform.

  • Retinal Pigment epithelial tear after intravitreal bevacizumab injection
    American Journal of Ophthalmology, 2006
    Co-Authors: Chirag Shah, Jason Hsu, Sunir J Garg, David H Fischer, Richard S Kaiser
    Abstract:

    Purpose To report two cases of a Retinal Pigment epithelial (RPE) tear after intravitreal bevacizumab injection for exudative age-related macular degeneration (AMD). Design Observational case series. Methods Two patients presented with occult choroidal neovascularization secondary to AMD. Both patients received intravitreal bevacizumab injections. Results The first patient developed a RPE tear shortly after a third intravitreal bevacizumab injection. The second patient developed a RPE tear 10 days after a second intravitreal bevacizumab injection. Conclusions Although RPE tears may occur spontaneously as part of the natural history of exudative AMD, patients may develop visually devastating RPE tears after repeat intravitreal bevacizumab injection. Further studies are needed to determine the incidence of RPE tears after intravitreal bevacizumab injections.