The metabotrophic NGF and BDNF: an emerging concept.

The field of neurotrophins, particularly, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), has witnessed a number of breakthroughs in recent years. There is evidence now that NGF and BDNF mediate multiple biological phenomena, ranging from the Rita Levi Montalcini's neurotrophic through immunotrophic to epitheliotrophic and nociceptive effects. In 2003 we, for the first time, enriched the "NGFome" with one more expression presented in our concept of NGF metabotrophicity, also that of BDNF. This envisages that these two factors may operate as metabotrophins, that is, involved in the maintenance of cardiometabolic homeostasis (glucose and lipid metabolism as well as energy balance, cardioprotection, and wound healing). Recent results also demonstrated that the circulating and/or tissue levels of NGF and BDNF are altered in cardiometabolic diseases (atherosclerosis, obesity, type 2 diabetes, metabolic syndrome, and type 3 diabetes). Altogether, a hypothesis of metabotrophic deficit due to the reduction of NGF/BDNF availability and/or utilization was raised, and implicated in the pathogenesis of cardiometabolic diseases. This may cultivate a novel pathogenic and therapeutic thinking for these diseases.