June 2014

Ketone bodies serve as a source of energy for the heart muscle and brain. They also have a protective effect in ischemic stroke. But whether the protective effect of the ketone bodies is due to their supply of energy was unclear. By binding to the G-protein coupled HCA₂ receptor in lipocytes and immunocytes, the ketone body beta-hydroxybutyrate also serves regulatory functions. In order to clarify the function of HCA₂ in stroke, DZHK investigators led by Markus Schwaninger (Lübeck) examined the effect of a ketogenic diet in mice that lacked HCA₂. They found that HCA₂ mediates the effect of a ketogenic diet. Further analyses showed that monocytes and macrophages that are derived from the bone marrow and migrate to the brain are responsible for the effect of HCA₂. HCA₂ appears to activate protective properties in these cells. Fortunately, various HCA₂ agonists already exist which can now be tested in models of ischemia. The researchers report on their findings in Nature Communications doi:10.1038/ncomms4944.