2 results for Ablonczy, Z

  • Spatial localization of A2E in the retinal pigment epithelium.

    Grey, Angus; Crouch, RK; Koutalos, Y; Schey, KL; Ablonczy, Z (2011-06)

    Journal article
    The University of Auckland Library

    Lipofuscin, a fluorescent lysosomal pigment made of lipophilic molecules, is associated with age-related pathophysiological processes in the retinal pigment epithelium (RPE). The best-characterized components of lipofuscin are A2E and its oxides, but a direct spatial correlation with lipofuscin has not previously been possible.

    View record details
  • Molecule-specific imaging and quantitation of A2E in the RPE

    Ablonczy, Z; Gutierrez, DB; Grey, Angus; Schey, KL; Crouch, RK (2012)

    Book item
    The University of Auckland Library

    Lipofuscin accumulates in the aging retinal pigment epithelium (RPE). It is identified by its fluorescence; however, lipofuscin is a complex mixture, and fluorescence is not specific enough to identify its individual components. Utilizing matrix-assisted laser desorption-ionization imaging, we have recently determined the spatial distribution of lipofuscin components across the RPE. One of the most abundant signals was that of the bis-retinoid A2E, a byproduct of the visual cycle. To better understand the accumulation of A2E, we studied wild-type (wt), Rpe65 −/− , and Abca4 −/− mice. A2E was not found in Rpe65 −/− animals. In wt animals, A2E was most abundant in the center of the RPE and diminished toward the periphery. In contrast, the A2E signal was more intense and uniformly distributed in Abca4 −/− mice. The oxidized forms of A2E were also spatially localized. Furthermore, a highly sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was utilized to quantitate A2E. A2E oxidation sites were determined both in organic extracts and directly from the tissue. The ability to image a specific retinoid and its modified products from fresh tissue suggests wide applicability in the research and potential treatments of retinal degeneration.

    View record details