Retina in focus

is the winner of the second prize in the recent Olympus–Current Biology photomicrography competition. The retina has been flat-mounted and stained by indirect immunofluorescence to reveal astrocytes (green) and blood vessels (orange/yellow) that are tightly associated with each other, forming a fine network over the retinal surface. Astrocytes (a type of glial cell) are critical for the development and maintenance of the retinal blood vessels. Aberrant vessel growth can disrupt the retina and lead to vascular retinopathy: the main cause of blindness in the developed world. The astrocytes are thought to mediate retinal blood vessel growth by secreting vascular endothelial growth factor (VEGF). The VEGF gene is regulated by oxygen concentration, and when oxygen levels are abnormal, for example in a premature baby on a ventilator or in certain diabetic patients, the growth of retinal blood vessels can be aberrant. Here, astrocytes were visualized using antibodies against glial fibrillary acidic protein, and blood vessels were visualized using antibodies against collagen IV. Imaging was through a confocal microscope. Dr Richardson's laboratory will receive an Olympus µ zoom camera as a prize. Some of the runners up in the competition will appear in this column in the coming issues.