Research has now demonstrated that the increased blood flow around the body stimulates the delicate lining of the blood vessels. This lining, called the endothelium, releases important chemicals into the blood. This includes nitric oxide, which causes all blood vessels to relax (dilate), further increasing blood flow around the body. There are also strong beneficial reductions in inflammatory substances. Increased flow also stimulates the bone marrow to release stems cells for new blood vessel growth (angiogenesis). The benefits of ECP lead to continued improvements even after the course of treatment is completed.