Cardiotrophin-1: a new player in energy metabolism with potential therapeutic application

The incidence of obesity and associated co-morbidities such as insulin resistance, dyslipidemia and cardiovascular diseases has reached epidemic proportions worldwide. As a result, new therapeutic options for the treatment of these conditions are clearly warranted. With the failure of leptin as anti-obesity therapy, recent research has focused on the gp130 receptor ligands, in particular CNTF, as potential therapeutic agents for obesity [1]. This cytokine induces weight loss and improves glucose tolerance [2] but its body weight lowering activity in clinical trials was limited [3]. On the other hand, the effects of IL-6 (another gp130 ligand) on energy metabolism remain controversial. Although IL-6 has been proposed to increase insulin resistance, the discovery that IL-6 is a myokine produced and released from skeletal muscle during exercise, led many to challenge this concept as insulin action is enhanced immediately after exercise [4]. In any case clinical use of IL-6 is hampered by its potent pro-inflammatory properties.