Progress in FY2017 includes the following: We wrote a commentary on a series of papers that individually appear well-done and convincing, yet fundamentally disagree. One group reported that interleukin-4 (IL-4) does not increase adipose thermogenesis and that activated macrophages do not synthesize catecholamines. This contrasts with prior findings that IL-4 activation of macrophages has been proposed to have a pivotal role in cold-induced thermogenesis by stimulating macrophage catecholamine production to recruit thermogenic beige or brite fat (1). Our interest in hypothermia is intimately tied to BAT, as induction of hypothermia involves complete inactivation of BAT, which recover reactivates it. Thus studies of drugs causing hypothermia should interact in the neural pathways that contribute to the regulation and control of BAT.
