Navegando por Palavras-chave "translational medical research"

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    ARPE-19 Cell Uptake of Small and Ultrasmall Superparamagnetic Iron Oxide
    (Informa Healthcare, 2014-04-01) Grottone, Gustavo Teixeira [UNIFESP]; Loureiro, Renata Ruoco [UNIFESP]; Covre, Joyce [UNIFESP]; Rodrigues, Eduardo Buchele [UNIFESP]; Gomes, José Álvaro Pereira [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Purpose: To investigate the cytotoxicity, cellular intake and magnetic field interaction of three superparamagnetic iron oxide (SPIO) and one ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles on ARPE-19 cells.Methods: Two FDA-approved SPIO nanoparticles (Endorem and Lumirem), one commercial SPIO(FluidMag-L) and one FDA-approved USPIO (Feraheme) were tested. Nanoparticle suspensions were diluted and prepared in high- (1000 Fe-ug/ml) and low- (100 Fe-ug/ml) dose suspensions. ARPE-19 cells were incubated in four 24-well plates and the medium changed every other day until cells attained 80% confluence. Nanoparticle cytotoxicity was evaluated using the XTT cytotoxicity assay. Cellular attraction was tested after digestion of the cells in collagenase A (1 mg/ml) overnight. A 3500 Gauss neodymium magnet was used to attract cells to the well walls. ARPE-19 cell ultrastructure was evaluated by transmission electron microscopy (TEM) to determine the specific locations of nanoparticles within the cell membranes.Results: Cytotoxicity assessment by the XTT assay revealed that ARPE-19 cells that were exposed to either concentration of Endorem, FLuidMag-L, Feraheme non-conjugated with protamine and heparin or Lumirem demonstrated no statistically significant toxicity. Cells exposed to Feraheme when conjugated with protamine and heparin presented severe toxicity in both concentrations. When a magnetic field was applied, all nanoparticle-containing samples, except Feraheme non-conjugated form, were promptly attracted. TEM and prussian blue staining examination revealed that Feraheme alone was not initially capable of cellular uptake. This issue was solved by conjugating Feraheme with protamine and heparin (although cytotoxicity was found on those samples). Endorem, FLuidMag-L, Feraheme conjugated form were found within the cytoplasm of ARPE-19 cells.Conclusions: Ferahame when conjugated with protamine and heparin was cytotoxic at the higher and lower doses, as revealed by the XTT assay. Endorem and FluidMag-L were not toxic at the studied concentrations. Feraheme non-conjugated solutions and Lumirem solutions provided were harmless but were not internalized by ARPE-19 cells. All the studied nanoparticles were attracted to the magnetic field except Feraheme in the non-conjugated form.
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    Bases da terapia celular magnética com endotélio corneal: cultura e magnetização celular
    (Universidade Federal de São Paulo (UNIFESP), 2014-09-30) Grottone, Gustavo Teixeira [UNIFESP]; Gomes, Jose Alvaro Pereira [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Purpose: To evaluate the foundations of human corneal endothelial cell therapy with magnetic and non-magnetic cells. Methods: Thirty six corneas donated by eye bank and twelve rabbits were used in this study. Human corneal endothelial cells previously cultured in vitro were divided in two groups: exposed or non-exposed to magnetic nanoparticles. Those cells were used as an attempt to regenerate our ex-vivo host corneas. Cell colonies were tracked after 7 days using an scanning laser ophthalmoscope with a excitation light of 488 nm. The rabbits were divided into two groups according to the treatment used: ABRASION or DESCEMET. After 30 days, corneal central thickness and edema of both grupos were recorded. Those corneas that presented clinical signs of bullous keratopathy underwent endothelial cell therapy. Results: Human corneal endothelial cells showed no toxicity when exposed to the studied nanoparticle(p=0.507). Endothelial cell failure experimental models were different when considering central corneal thickness after 30 days(p<0.001).Indeed, the group which expressed greater edema, also showed extensive fibrotic tissue at posterior corneal surface, thus, preventing the use of this model in our study. Both, non-magnetic and magnetic cells were found attached to posterior surface of corneas after 7 days of ex-vivo cultures. Conclusions: Human corneal endothelial cells from magnetic and non-magnetic groups attached to corneal posterior surface on ex-vivo hosts.