Nakano Developmental Cell 2019 (image) University of California - Los Angeles Health Sciences Share Print E-Mail Caption Microscopic images of a normal heart valve in a mouse, left, and a heart valve grown in a lab with heart-derived macrophages blocked, right. Without those macrophages, the valves are thick and deformed. Credit Developmental Cell/UCLA Broad Stem Cell Research Center Usage Restrictions None 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.