Axel Montagne, PhD, UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK, discusses the critical nature of precise blood-brain barrier (BBB) functioning for regulation of central nervous system (CNS) homeostasis. As mediator of communication between the periphery and the CNS, the BBB is necessary for controlling the influx and efflux of biological substance and toxins, preserving the brain’s microenvironment, and maintaining neuronal function. BBB dysfunction is seen with aging and is a known early biomarker of cognitive decline. Whether changes in the structural integrity of the BBB are causal in the process of cognitive decline is not yet known. This interview took place at the ESOC 2022 congress in Lyon, France.