Vascular endothelial growth factor B (VEGFB) is also known as VEGF-related factor (VRF), is a secreted O-glycosylated protein, which belongs to the PDGF/VEGF growth factor family. VEGFB is expressed in all tissues except liver. Highest levels found in heart, skeletal muscle and pancreas. VEGFB is growth factor for endothelial cells. VEGF-B seems to play a role only in the maintenance of newly formed blood vessels during pathological conditions. VEGF-B also plays an important role on several types of neurons. It is important for the protection of neurons in the retina and the cerebral cortex during stroke and of motoneurons during motor neuron diseases such as amyotrophic lateral sclerosis.VEGF-B167 binds heparin and neuropilin-1 whereas the binding to neuropilin-1 of VEGF-B186 is regulated by proteolysis.