Editorial: Small and mighty: Brain capillaries in health and disease

Capillaries are the smallest blood vessels and the major site for oxygen exchange, glucose delivery, and waste removal.Within the brain, the “small and mighty” capillaries

have become an area for active research in the past few years. Recent studies have shown that brain capillaries are key sensors of chemical cues derived from surrounding neurons and astrocytes, leading to vascular responses. Capillaries also sense intravascular forces, which can change during capillary occlusions that are commonly observed in disease (Longden et al., 2017, 2021; Harraz et al., 2018a,b, 2022; Cruz Hernández et al.,

2019; Bracko et al., 2021; Sancho et al., 2022). The capillary wall is formed of capillary endothelial cells and surrounding pericytes. Both cell types have been implicated in capillary function and dysfunction (Sagare et al., 2013; Kisler et al., 2017; Nortley et al., 2019; Dabertrand et al., 2021; Mughal et al., 2021). Other cell types—such as astrocytes, blood cells, and microglia—interact with capillaries leading to changes in cerebral blood flow. The Frontiers Research Topic [Small and mighty: Brain capillaries in health and disease] covers some aspects of capillary involvement in neurovascular coupling, capillary stalling, and pericyte pathophysiology.