Every inch inside our bodies is covered with a tree-like network of blood vessels. New branches grow from cells in the vessel walls that ‘sprout’ like shoots growing through the skin of a potato. This is controlled by molecules called growth factors. In these six-day-old mouse retinas (visualised using two techniques), new vessels are developing. A red fluorescent dye has been used to observe the patterns of two injected growth factors: VEGF-A (left two images) and VEGF-C (right two). Cell nuclei, both inside and outside the vessels, are stained blue, and the cells that make up the vessel walls are stained white. Both growth factors are densest around the vessel walls, and the green arrowheads point to where they have been taken into individual sprouting cells. Understanding this process may lead to new tools against diseases like cancer, as growth factors enable some tumours to develop their own blood supply.
Written by Emma Stoye
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.