After a heart attack, a type of immune cell can lessen the damaging inflammatory response in the organ by recognizing cells undergoing apoptosis, or programmed cell death. To mimic this protective effect, Smadar Cohen at Ben-Gurion University of the Negev in Beer-Sheva, Israel, and her group designed a liposome — a lipid-based bubble — with the molecule phosphatidylserine on its surface. This is abundant on apoptotic cells, and prompts the immune system's macrophage cells to secrete anti-inflammatory factors.

Credit: NATL ACAD. SCI.

The authors showed that mouse macrophages took up the liposomes and shifted to an anti-inflammatory mode. Rats injected with liposomes after an induced heart attack showed an accumulation of macrophages in the damaged area after four days (pictured with arrow). After four weeks, the rats also had a greater density of heart blood vessels than untreated animals and less remodelling of their left ventricle, a common after-effect of a heart attack.

Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1015623108 (2011)