Abstract
Purpose:
Ischemic retinopathy is associated with several vision threating complications, such as neural atrophy, vascular leakage and neovascularisation. Traditionally ischemia has been assessed by fluorescein angiography, visualising perfused vessels. Although this method does not provide any information about non-perfused vessels, it is often assumed that vessels in ischemic areas regress. Here we aim to learn more about the longterm fate of non-perfused vessels in the retinal vasculature.
Methods:
Optical coherence tomography (Avanti Angiovue SDOCT, Optovue, Inc. Fremont, CA, USA) was used to visualise perfusion as well as structural properties of the retinal vasculature in patients suffering from retinal vascular occlusions. In addition, post mortem tissue from a patient with long standing (6 years) central retinal vein occlusion (CRVO) was investigated, using immunohistochemistry on whole mount retina and paraffin sections to visualise blood vessel components and retinal cells.
Results:
Comparing OCT angiography (based on speckle variance) with en-face OCT images from selected retinal layers revealed that in ischemic areas of the retina non-perfused, larger vessels could be detected as hyper reflective structures. Furthermore, analysis of the CRVO postmortem tissue revealed perfect preservation of the basement membrane from all retinal vessels, including capillaries. However, these non-perfused “vessels sleeves” did not contain endothelial cells or pericytes.
Conclusions:
Our data suggests longterm preservation of vascular basement membrane in ischemic retina. This has implications for therapeutic approaches aiming to alleviate retinal ischemia via cell therapy.