Serelaxin

Serelaxin (RLX030) is an investigational drug for the treatment of acute heart failure (AHF), targeting the relaxin receptor. Serelaxin is a recombinant form of human relaxin-2, a hormone that (among other functions) is produced during pregnancy and mediates the haemodynamic changes that occur during this time, such as increased blood output of the heart and blood flow in the kidney. Human-relaxin-2 mediates vasodilation (widening of blood vessels) by increasing the production of nitric oxide (NO), a potent vasodilator. Activation of the relaxin receptor RXFP1 activates several enzymes in a phosphorylation cascade that eventually results in the activation of NO synthase in endothelial cells and the subsequent production of NO. Relaxin can also bind to a secondary receptor, endothelial B receptor, which is upregulated as a result of the previous pathway. Relaxin binding to endothelial B receptor on endothelial cells also induces vasodilation.