Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.
German Center for Diabetes Research (DZD e.V.), Tübingen, Germany.
J Neuroendocrinol. 2020 Dec;32(12):e12907. doi: 10.1111/jne.12907. Epub 2020 Oct 6.
There is growing evidence that obesity is associated with inflammation in the brain, which could contribute to the pathogenesis of obesity. In humans, it is challenging to detect brain inflammation in vivo. Recently, quantitative magnetic resonance imaging (qMRI) has emerged as a tool for characterising pathophysiological processes in the brain with reliable and reproducible measures. Proton density imaging provides quantitative assessment of the brain water content, which is affected in different pathologies, including inflammation. We enrolled 115 normal weight, overweight and obese men and women (body mass index [BMI] range 20.1-39.7 kg m , age range 20-75 years, 60% men) to acquire cerebral water content mapping in vivo using MRI at 3 Tesla. We investigated potential associations between brain water content with anthropometric measures of obesity, body fat distribution and whole-body metabolism. No global changes in water content were associated with obesity. However, higher water content values in the cerebellum, limbic lobe and sub-lobular region were detected in participants with higher BMI, independent of age. More specifically, the dorsal striatum, hypothalamus, thalamus, fornix, anterior limb of the internal capsule and posterior thalamic radiation showed the strongest relationship with BMI, independent of age. In a subgroup with available measurements (n = 50), we identified visceral adipose tissue to be the strongest tested link between higher water content values and obesity. Individuals with metabolic syndrome had the highest water content values in the hypothalamus and the fornix. There is accumulating evidence that inflammation of the hypothalamus contributed to obesity-associated insulin resistance in that area. Whether brain inflammation is a cause or consequence of obesity in humans still needs to be investigated using a longitudinal study design. Using qMRI, we were able to detect marked water content changes in young and older obese adults, which is most likely the result of chronic low-grade inflammation.
越来越多的证据表明，肥胖与大脑炎症有关，而这种炎症可能是肥胖发病机制的原因之一。在人类中，很难在体内检测到大脑炎症。最近，定量磁共振成像（qMRI）已成为一种可靠且可重复的工具，可用于对大脑的病理生理过程进行特征描述。质子密度成像提供了对脑水含量的定量评估，该指标在包括炎症在内的不同病理状态下会受到影响。我们招募了 115 名正常体重、超重和肥胖的男性和女性（BMI 范围为 20.1-39.7kg/m2，年龄范围为 20-75 岁，60%为男性），使用 3T MRI 对其进行体内脑水含量图谱成像。我们研究了脑水含量与肥胖的人体测量学指标、体脂分布和全身代谢之间的潜在关联。肥胖与大脑水含量无全局变化相关。然而，在 BMI 较高的参与者中，检测到小脑、边缘叶和小叶区的水含量值较高，而与年龄无关。更具体地说，背侧纹状体、下丘脑、丘脑、穹窿、内囊前肢和丘脑后辐射与 BMI 的相关性最强，与年龄无关。在有可用测量值的亚组（n=50）中，我们发现内脏脂肪组织与更高的水含量值和肥胖之间的关系最强。代谢综合征患者的下丘脑和穹窿中的水含量值最高。越来越多的证据表明，下丘脑炎症可能导致该区域与肥胖相关的胰岛素抵抗。使用纵向研究设计，仍需要研究大脑炎症是人类肥胖的原因还是结果。通过 qMRI，我们能够检测到年轻和老年肥胖成年人的脑水含量发生明显变化，这很可能是慢性低度炎症的结果。
