Biomarkers In Small Vessel Disease

Abstract

The human brain weighs only 3lb, yet it contains 400 miles of blood vessels and 25% of your blood goes to supply the brain with each heartbeat. Cerebral small blood vessels are surrounded by a network of glial cells and pericytes to make up the neurovascular unit. The intact neurovascular unit is essential for a fully functional blood brain barrier. Vascular risk factors such as diabetes and hypertension have been shown to cause small vessel damage, which is visualised by neuroimaging and generally referred to as “small vessel disease” (SVD). Typical features on the MRI include white matter hyperintensities, cerebral microbleeds, lacunar infarcts, and perivascular space. This cerebral SVD may or may not in turn lead to different clinical presentations including memory decline, gait abnormalities and psychiatric illnesses. However, what are the biological mechanisms that determine whether SVD leads to clinical presentations, and are there any evidence-based treatment strategies to improve clinical outcome? The phenomenon of SVD is further complicated by co-existing pathologies such as cerebral aging, Alzheimer’s disease (e.g. in support of the vascular hypothesis), previous brain trauma, and Parkinson’s disease. Understanding how theses interact, as well as how they jointly lead to neuronal and psycho-cognitive dysfunction, is essential in tackling this epidemic in the rapidly aging population. In this lecture, I will briefly describe the epidemiology, pathology, and clinical manifestation of SVD. I will then examine the different clinical, blood, CSF, neuroimaging, EEG and cognitive biomarkers of SVD. Using new neuroimaging techniques, we can improve our understanding of this interesting disease state.