Nano Lett. 11, 4411–4414 (2011)

Credit: © 2011 ACS

After myocardial infarction, blood vessels in the heart's left ventricle become permeable. It is also known that an infarcted heart overexpresses the AT1 receptor for angiotensin — a peptide in the blood that induces vasoconstriction and therefore an increase in blood pressure. Now, Tal Dvir and colleagues have designed nanoparticles that target infarcted hearts, by taking advantage of the leaky vasculature and the abundance of AT1. The researchers synthesized nano-sized liposomes conjugated with a peptide specific for the AT1 receptor, and show that in incubated cardiac cells approximately half of the cells were targeted by these liposomes, compared with less than one third targeted by liposomes conjugated with a peptide bearing the same amino acids, but in a scrambled order. After intravenous injection in mice, the liposomes accumulated mostly in the left ventricle of the injured hearts, probably because of the enhanced permeation and retention effect occurring in the permeable vasculature; no accumulation was seen in healthy hearts. Drug-loaded, heart-targeting liposomes could become an attractive alternative to direct injection of therapeutics into the injured heart.