Koskensalo Kalle, Raiko Juho, Saari Teemu, Saunavaara Virva, Eskola Olli, Nuutila Pirjo, Saunavaara Jani, Parkkola Riitta, Virtanen Kirsi A
Turku PET Centre and.
Turku PET Centre.
J Clin Endocrinol Metab. 2017 Apr 1;102(4):1200-1207. doi: 10.1210/jc.2016-3086.
The metabolic activity of human brown adipose tissue (BAT) has been previously examined using positron emission tomography (PET). The aim of this study was to use proton magnetic resonance spectroscopy (1H MRS) to investigate whether the temperature and the fat fraction (FF) of BAT and white adipose tissue (WAT) are associated with BAT metabolic activity determined by deoxy-2-18F-fluoro-d-glucose (18F-FDG)-PET.
Ten healthy subjects (four women, six men; 25 to 45 years of age) were studied using PET-magnetic resonance imaging during acute cold exposure and at ambient room temperature. BAT and subcutaneous WAT 1H MRS were measured. The tissue temperature and the FF were derived from the spectra. Tissue metabolic activity was studied through glucose uptake using dynamic FDG PET scanning during cold exposure. A 2-hour hyperinsulinemic euglycemic clamp was performed on eight subjects.
The metabolic activity of BAT associated directly with the heat production capacity and inversely with the FF of the tissue. In addition, the lipid-burning capacity of BAT associated with whole-body insulin sensitivity. During cold exposure, the FF of BAT was lower than at room temperature, and cold-induced FF of BAT associated inversely with high-density lipoprotein and directly with low-density lipoprotein cholesterol.
Both 1H MRS-derived temperature and FF are promising methods to study BAT activity noninvasively. The association between the lipid-burning capacity of BAT and whole-body insulin sensitivity emphasizes the role of BAT in glucose handling. Furthermore, the relation of FF to high-density lipoprotein and low-density lipoprotein cholesterol suggests that BAT has a role in lipid clearance, thus protecting tissues from excess lipid load.
此前已使用正电子发射断层扫描（PET）对人体棕色脂肪组织（BAT）的代谢活性进行了研究。本研究的目的是使用质子磁共振波谱（1H MRS）来探究BAT和白色脂肪组织（WAT）的温度及脂肪分数（FF）是否与由脱氧 - 2 - 18F - 氟 - D - 葡萄糖（18F - FDG） - PET测定的BAT代谢活性相关。
对10名健康受试者（4名女性，6名男性；年龄25至45岁）在急性冷暴露期间及室温环境下进行PET - 磁共振成像研究。测量BAT和皮下WAT的1H MRS。从波谱中得出组织温度和FF。在冷暴露期间通过动态FDG PET扫描利用葡萄糖摄取来研究组织代谢活性。对8名受试者进行了2小时的高胰岛素正常血糖钳夹试验。
BAT的代谢活性与产热能力直接相关，与组织的FF呈负相关。此外，BAT的脂质燃烧能力与全身胰岛素敏感性相关。在冷暴露期间，BAT的FF低于室温时，且冷诱导的BAT的FF与高密度脂蛋白呈负相关，与低密度脂蛋白胆固醇呈正相关。
1H MRS得出的温度和FF都是无创研究BAT活性的有前景的方法。BAT的脂质燃烧能力与全身胰岛素敏感性之间的关联强调了BAT在葡萄糖处理中的作用。此外，FF与高密度脂蛋白和低密度脂蛋白胆固醇的关系表明BAT在脂质清除中起作用，从而保护组织免受过多脂质负荷的影响。
