Cardiovascular disease, the most common cause of death, is the result of oxygen deprivation as blood perfusion to affected tissue is prevented. To halt the development of the disease and to promote healing, re-establishment of blood flow is crucial. Researchers at Uppsala University have now discovered that one of the most common immune cells in the human body, macrophages, play an important role in re-establishing and controlling blood flow, something that can be used to develop new drugs.