A Simple Review of Small Vessel Disease Manifestation in the Brain, Retina, and Kidneys

Abstract

Small blood vessels express specific phenotypical and functional characteristics throughout the body. Alterations in the microcirculation contribute to many correlated physiological and pathological events in related organs. Factors such as comorbidities and genetics contribute to the complexity of this topic. Small vessel disease primarily affects end organs that receive significant cardiac output, such as the brain, kidney, and retina. Despite the differences in location, concurrent changes are seen in the micro-vasculature of the brain, retina, and kidneys under pathological conditions due to their common histological, functional, and embryological characteristics. While the cardiovascular basis of pathology in association with the brain, retina, or kidneys has been well documented, this is a simple review that uniquely considers the relationship between all three organs and highlights the prevalence of coexisting end organ injuries in an attempt to elucidate connections between the brain, retina, and kidneys, which has the potential to transform diagnostic and therapeutic approaches.

Keywords: cerebrovascular disease; chronic kidney disease; diagnostic imaging; retinopathy; small vessel disease; stroke; white matter.

Figure 1

Similarities in anatomical structure of vascular barriers in the brain, retina, and kidneys. The vascular barriers of the brain, retina, and kidneys have many structural similarities, including basement membranes containing type IV collagen, an outer layer with analogous projections (glomerular podocyte foot processes, retinal epithelial cell projections, and astrocyte foot processes), and a fenestrated endothelial cell layer in the glomerulus and retina. Created using BioRender.com on 26 August 2022.

Figure 2

Process of parallel onset end-organ dysfunction. Flowchart demonstrating the interactions between shared systemic risk factors, resulting in endothelial cell changes and end-organ manifestations in the kidneys, brain, and retina. Created using BioRender.com. GFR glomerular filtration rate, SVD small vessel disease. Created using BioRender.com on 25 August 2022.