GDF15 and sarcopenia: GDF-15 has been repeatedly identified as a marker of mortality in a wide range of health and disease.39 Sarcopenia and cachexia are also almost universally associated with increased risk of morbidity and mortality across disease states.40 Our data add more evidence suggesting that GDF-15 and its downstream signalling molecule TAK1 may be a potential target for future therapeutic intervention aimed at improving muscle mass, exercise tolerance, quality of life and possibly even mortality across a wide range of conditions.