No abstract

No abstract

No abstract

The elasticity of Bruch's membrane-choroid complex decreases with age while recoil capacity does not. The decrease was not exaggerated in AMD.

No abstract

Zinc levels are high in ocular tissues and the distribution is non-uniform. Zinc is particularly concentrated in the corneal epithelium and posterior stroma. Zinc is the most abundant trace metal in the retina. Bound-zinc is particularly located in the inner nuclear layer, (e.g. forming part of the structure of zinc finger transcription factors), while loosely-bound zinc is prominent in the retinal pigment epithelium and photoreceptor layers. Loosely-bound zinc ions in the photoreceptors might play a role in the phototransduction cascade and rhodopsin regeneration. Loosely-bound zinc is also found in presynaptic vesicles of photoreceptor cells in the outer plexiform and inner plexiform layers and can be synaptically released to affect both ionotropic and metabotropic receptors and also ion channels to modulate neurotransmission. The correct amount of loosely-bound zinc ions is maintained by regulating the function of zinc transporters, sensors and trafficking/storage proteins (i.e. metallothionein). The retinal homeostasis of zinc is dysregulated in systemic zinc depletion, aging and diseases such as age-related macular degeneration. Manipulation of retinal zinc metabolism in these situations might improve visual function.

No abstract

Inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify the total amount of trace elements in retina from adult male Sprague-Dawley rats (n = 6). Concentration of trace elements within individual retinal areas in frozen sections of the fellow eye was established with the use of two methodologies: (1) particle-induced X-ray emission (PIXE) in combination with 3D depth profiling with Rutherford backscattering spectrometry (RBS) and (2) synchrotron X-ray fluorescence (SXRF) microscopy. The most abundant metal in the retina was zinc, followed by iron and copper. Nickel, manganese, chromium, cobalt, selenium and cadmium were present in very small amounts. The PIXE and SXRF analysis yielded a non-homogenous pattern distribution of metals in the retina. Relatively high levels of zinc were found in the inner part of the photoreceptor inner segments (RIS)/outer limiting membrane (OLM), inner nuclear layer and plexiform layers. Iron was found to accumulate in the retinal pigment epithelium/choroid layer and RIS/OLM. Copper in turn, was localised primarily in the RIS/OLM and plexiform layers. The trace elements iron, copper, and zinc exist in different amounts and locations in the rat retina.