GM pacemakers

Embryonic heart cells possess intrinsic pacemaker activity, but as development progresses the overall rate and rhythm of the heart is determined by a small number of pacemaker cells situated within compact 'nodes'. In September 12 Nature, Junichiro Miake and colleagues at Johns Hopkins University School of Medicine, Baltimore, USA, show that gene transfer techniques can transform adult ventricular myocytes into a biological pacemaker (Nature 2002, 419:132–133).

Miake et al. used viral gene transfer to produce myocytes with dominant-negative inhibition of Kir2-encoded inward-rectifier potassium channels. They observed that Kir2.1AAA-transduced myocytes exhibited spontaneous activity similar to a pacemaker node or a stable resting potential from which prolonged action potentials could be elicited.

"Our results indicate that genetically engineered pacemakers could be developed as a possible alternative to implantable electronic devices," conclude the authors.