Program in Molecular Medicine, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
Am J Physiol Heart Circ Physiol. 2011 Oct;301(4):H1425-37. doi: 10.1152/ajpheart.00376.2011. Epub 2011 Jul 15.
Thoracic perivascular adipose tissue (PVAT) is a unique adipose depot that likely influences vascular function and susceptibility to pathogenesis in obesity and the metabolic syndrome. Surprisingly, PVAT has been reported to share characteristics of both brown and white adipose, but a detailed direct comparison to interscapular brown adipose tissue (BAT) has not been performed. Here we show by full genome DNA microarray analysis that global gene expression profiles of PVAT are virtually identical to BAT, with equally high expression of Ucp-1, Cidea, and other genes known to be uniquely or very highly expressed in BAT. PVAT and BAT also displayed nearly identical phenotypes upon immunohistochemical analysis, and electron microscopy confirmed that PVAT contained multilocular lipid droplets and abundant mitochondria. Compared with white adipose tissue (WAT), PVAT and BAT from C57BL6/J mice fed a high-fat diet for 13 wk had markedly lower expression of immune cell-enriched mRNAs, suggesting resistance to obesity-induced inflammation. Indeed, staining of BAT and PVAT for macrophage markers (F4/80 and CD68) in obese mice showed virtually no macrophage infiltration, and FACS analysis of BAT confirmed the presence of very few CD11b(+)/CD11c(+) macrophages in BAT (1.0%) compared with WAT (31%). In summary, murine PVAT from the thoracic aorta is virtually identical to interscapular BAT, is resistant to diet-induced macrophage infiltration, and thus may play an important role in protecting the vascular bed from inflammatory stress.
胸主动脉周围血管脂肪组织（PVAT）是一种独特的脂肪组织，可能影响血管功能和肥胖及代谢综合征发病机制的易感性。令人惊讶的是，PVAT 被报道具有棕色和白色脂肪的特征，但尚未对其与肩胛间棕色脂肪组织（BAT）进行详细的直接比较。在这里，我们通过全基因组 DNA 微阵列分析表明，PVAT 的整体基因表达谱与 BAT 几乎相同，Ucp-1、Cidea 和其他已知在 BAT 中特异性或高度表达的基因的表达水平同样高。免疫组织化学分析显示，PVAT 和 BAT 也表现出几乎相同的表型，电子显微镜证实 PVAT 含有多房脂质滴和丰富的线粒体。与白色脂肪组织（WAT）相比，饲喂高脂肪饮食 13 周的 C57BL6/J 小鼠的 PVAT 和 BAT 中富含免疫细胞的 mRNA 表达明显降低，表明其对肥胖诱导的炎症具有抵抗力。事实上，在肥胖小鼠的 BAT 和 PVAT 上对巨噬细胞标志物（F4/80 和 CD68）进行染色显示几乎没有巨噬细胞浸润，而对 BAT 的 FACS 分析证实，与 WAT（31%）相比，BAT 中存在的 CD11b（+）/CD11c（+）巨噬细胞非常少（1.0%）。总之，来自胸主动脉的鼠 PVAT 与肩胛间 BAT 几乎相同，对饮食诱导的巨噬细胞浸润具有抵抗力，因此可能在保护血管床免受炎症应激方面发挥重要作用。
