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Christopher P Ardeljan, Mones S Abu-Asab, Maria Mercedes Campos; Choriocapillaris Loss of Endothelial Polarity and Fenestration May Be Contributing Factors in AMD. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4997.
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© ARVO (1962-2015); The Authors (2016-present)
This study aims to uncover and interpret the ultrastructural abnormalities in the choriocapillaris in AMD. Published ultrastructural reports of AMD are scarce and have not addressed abnormalities in the choriocapillaris and their pathological implications. This study will examine the choriocapillaris of the macular and peripheral regions in AMD patients using electron microscopy, since whether changes exist between the two regions has not been addressed before.
An ultrastructural examination was performed on the choroidal macular and peripheral regions of 7 AMD donors. All of the donors were over 80 years old. The eyes where fixed in formalin, and macular and temporal regions were dissected out separately. The specimens were prepared for transmission electron microscopy as follows: tissues were embedded in epoxy resin, sectioned at 90nm thickness, stained with uranyl acetate and lead citrate, and viewed with a JOEL JM-1010 TEM. Diameters of the choriocapillaris’ vessels adjacent to Bruch’s membrane were measured in the macular and temporal regions.
Endothelial cells of the choriocapillaris showed loss of fenestration, and anteriorly hypertrophic or complete lack of cytoplasm. Nuclei of endothelial cells were mostly hypertrophic and majority were anteriorly displaced toward Bruch’s membrane side rather than the usual lateral or posterior positions (i.e., loss of normal polarity). Pericytes were degenerate and the basement membranes were scant. Cellular debris was found between the choriocapillaris and Bruch’s membrane. The average diameter of capillaries was within the normal range in both the macula and temporal regions (6.1-7.8 μm).
AMD choriocapillaris showed ultrastructural aberrations that have not been reported before; most significant are endothelial abnormalities such as the loss of polarity of the endothelial cells. Nuclei of normal endothelial cells are usually posteriorly located at the scleral side of the capillary and not anteriorly at the side of Bruch’s membrane. The confluence of a number of ultrastructural aberrations within the choriocapillaris and the accumulation of cellular debris below Bruch’s membrane indicate perfusion abnormalities in AMD. No significant differences in these ultrastructural aberrations or in vessel size were found between the macular and peripheral choroidal regions.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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