As the control centre of our behaviours and most bodily functions, the brain is an especially precious organ. Consequently, it has its own unique protective shield: the blood-brain barrier – a tightly packed wall of endothelial cells lining the brain’s capillaries. Minimising transport of substances from the blood, the barrier thereby largely prevents pathogens, toxic proteins or other harmful agents from causing potentially fatal brain damage. Development of the barrier begins in the early embryo and is dependent on pericytes (the cells labeled blue in this embryonic mouse brain), which surround the growing vessels. Pericytes are present in all tissues, but scientists have learnt that brain pericytes express a special protein – Foxf2 – that drives barrier formation. Mice lacking this protein developed abnormal, leaky barriers and suffered bleeding on the brain – a cause of stroke. The findings suggest that aberrant expression of Foxf2 in pericytes might increase a person’s stroke susceptibility.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.