Macrophages (image) Uppsala University Share Print E-Mail Caption Macrophages (green) accumulate around blood vessels in damaged tissue to regulate blood flow. Credit David Ahl Usage Restrictions May only be published in connection to reports about the study "Perivascular macrophages regulate blood flow following tissue damage" or after permission from David Ahl. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.