Obesity is associated with increasing cardiometabolic morbidity and mortality worldwide. Not everyone with obesity, however, develops metabolic complications. Brown adipose tissue (BAT) has been suggested as a promoter of leanness and metabolic health. To date, little is known about the prevalence and metabolic function of BAT in subjects with severe obesity, a population at high cardiometabolic risk. In this cross-sectional study, we included 40 individuals with WHO class II-III obesity (BMI ≥ 35 kg/m²). Employing a 150-minute personalized cooling protocol and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography, cold-activated BAT was detectable in 14 (35%) of the participants. Cold-induced thermogenesis was significantly higher in participants with detectable BAT compared to those without. Notably, individuals with obesity and active BAT had 28.8% lower visceral fat mass despite slightly higher total fat mass compared to those without detectable BAT ¹⁸F-FDG uptake. This was accompanied by lower insulin resistance and systemic inflammation and improved NAFLD parameters, all adjusted for age, sex, and percent body fat. Contrary to previous assumptions, we show here that a significant fraction of individuals with severe obesity has active BAT. We found that decreased BAT ¹⁸F-FDG uptake was not associated with adiposity per se but with higher visceral fat mass. In summary, active BAT is linked to a healthier metabolic phenotype in obesity.

肥胖与全球心脏代谢发病率和死亡率的增加有关。然而，并非所有肥胖患者都会出现代谢并发症。棕色脂肪组织（BAT）被认为是瘦身和代谢健康的促进剂。迄今为止，对于重度肥胖（心脏代谢风险较高的人群）受试者中 BAT 的患病率和代谢功能知之甚少。在这项横断面研究中，我们纳入了 40 名 WHO II-III 级肥胖患者（BMI ≥ 35 kg/m ² ）。采用 150 分钟个性化冷却方案和¹⁸ F-氟脱氧葡萄糖正电子发射断层扫描/计算机断层扫描，在 14 名 (35%) 参与者中检测到冷激活 BAT。与没有可检测到 BAT 的参与者相比，寒冷诱导的生热作用明显更高。值得注意的是，与未检测到 BAT ¹⁸ F-FDG 摄取的人相比，肥胖且活跃 BAT 的个体尽管总脂肪量略高，但内脏脂肪量降低了 28.8%。伴随着较低的胰岛素抵抗和全身炎症以及改善的 NAFLD 参数，所有这些参数都根据年龄、性别和体脂百分比进行了调整。与之前的假设相反，我们在此表明​​，相当一部分严重肥胖的个体具有活跃的 BAT。我们发现 BAT ¹⁸ F-FDG 摄取减少与肥胖本身无关，但与内脏脂肪量增加有关。总之，活跃的 BAT 与肥胖患者更健康的代谢表型有关。