The vascular geometry of the choriocapillaris is associated with spatially heterogeneous molecular exchange with the outer retina.

Autor: Faust CD; John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA., Klettner CA; Department of Mechanical Engineering, University College London, London, UK., Toso M; John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA., Hageman GS; John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA., Eames I; Department of Mechanical Engineering, University College London, London, UK., Luthert PJ; Institute of Ophthalmology, University College London, London, UK., Zouache MA; John A. Moran Eye Center, Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA.
Jazyk: angličtina
Zdroj: The Journal of physiology [J Physiol] 2024 Apr; Vol. 602 (7), pp. 1273-1295. Date of Electronic Publication: 2024 Mar 21.
DOI: 10.1113/JP285050
Abstrakt: Vision relies on the continuous exchange of material between the photoreceptors, retinal pigment epithelium and choriocapillaris, a dense microvascular bed located underneath the outer retina. The anatomy and physiology of the choriocapillaris and their association with retinal homeostasis have proven difficult to characterize, mainly because of the unusual geometry of this vascular bed. By analysing tissue dissected from 81 human eyes, we show that the thickness of the choriocapillaris does not vary significantly over large portions of the macula or with age. Assessments of spatial variations in the anatomy of the choriocapillaris in three additional human eyes indicate that the location of arteriolar and venular vessels connected to the plane of the choriocapillaris is non-random, and that venular insertions cluster around arteriolar ones. Mathematical models built upon these anatomical analyses reveal that the choriocapillaris contains regions where the transport of passive elements is dominated by diffusion, and that these diffusion-limited regions represent areas of reduced exchange with the outer retina. The width of diffusion-limited regions is determined by arterial flow rate and the relative arrangement of arteriolar and venular insertions. These analyses demonstrate that the apparent complexity of the choriocapillaris conceals a fine balance between several anatomical and functional parameters to effectively support homeostasis of the outer retina. KEY POINTS: The choriocapillaris is the capillary bed supporting the metabolism of photoreceptors and retinal pigment epithelium, two critical components of the visual system located in the outer part of the retina. The choriocapillaris has evolved a planar multipolar vascular geometry that differs markedly from the branched topology of most vasculatures in the human body. Here, we report that this planar multipolar vascular geometry is associated with spatially heterogenous molecular exchange between choriocapillaris and outer retina. Our data and analyses highlight a necessary balance between choriocapillaris anatomical and functional parameters to effectively support homeostasis of the outer retina.
(© 2024 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)
Databáze: MEDLINE
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