These indigo blobs are the nuclei of heart muscle cells, viewed under a microscope. When exposed to a protein called apelin, the cells pucker at the binding site making them look, from the side, like little hearts. Scott Metzler, a postdoc at the Stanford Cardiovascular Institute who studies the in utero forces that shape the heart, made the discovery while investigating apelin’s role in development and its potential for treating heart failure. For Metzler, who was born with a serious cardiac defect, this area of study is—ahem—close to his heart.
Photo: Scott A. Metzler
