Cinti S
Institute of Normal Human Morphology, Faculty of Medicine, University of Ancona, Ancona, Italy.
J Endocrinol Invest. 2002 Nov;25(10):823-35. doi: 10.1007/BF03344046.
In mammals, the adipose organ is a multi-depot organ made of two tissue types, the white and brown adipose tissues, which collaborate in partitioning the energy contained in lipids between thermogenesis and the other metabolic functions. It consists of several sc and visceral depots. Some areas of these depots are brown and correspond to brown adipose tissue, while many are white and correspond to white adipose tissue. White areas contain a variable amount of brown adipocytes and their number varies with age, strain and environmental conditions. Brown and white adipocyte are morphologically different. At light microscopy level, brown adipocytes have cytoplasmic lipids arranged as numerous small droplets (multilocularity), while white adipocytes have cytoplasmic lipids arranged in a unique vacuole (unilocularity). Ultrastructurally, brown adipocytes have numerous big mitochondria packed with cristae and containing the thermogenic uncoupling protein 1 (UCP1). In vivo and in vitro studies have shown that the differentiation process of brown and white adipocytes shows distinctive features. Nevertheless, the origin of the adipocyte precursor is still unknown. Recent data have stressed the plasticity of the adipose organ in adult animals. Indeed, under peculiar conditions fully differentiated, white adipocytes can transdifferentiate into brown adipocytes, and viceversa. The ability of the adipose organ to interconvert its main cytotypes in order to meet changing metabolic needs is highly pertinent to the physiopathology of obesity and related to therapeutic strategies.
在哺乳动物中，脂肪器官是一种多部位器官，由白色和棕色两种脂肪组织构成，它们协同作用，在产热和其他代谢功能之间分配脂质所含的能量。它由多个皮下和内脏脂肪储存部位组成。这些储存部位的一些区域呈棕色，对应棕色脂肪组织，而许多区域呈白色，对应白色脂肪组织。白色区域含有数量不等的棕色脂肪细胞，其数量随年龄、品系和环境条件而变化。棕色和白色脂肪细胞在形态上有所不同。在光学显微镜水平下，棕色脂肪细胞的细胞质脂质呈许多小液滴排列（多泡性），而白色脂肪细胞的细胞质脂质则排列在一个独特的液泡中（单泡性）。在超微结构上，棕色脂肪细胞有许多充满嵴且含有产热解偶联蛋白1（UCP1）的大线粒体。体内和体外研究表明，棕色和白色脂肪细胞的分化过程具有独特特征。然而，脂肪细胞前体的起源仍然未知。最近的数据强调了成年动物脂肪器官的可塑性。事实上，在特殊条件下，完全分化的白色脂肪细胞可以转分化为棕色脂肪细胞，反之亦然。脂肪器官为满足不断变化的代谢需求而相互转化其主要细胞类型的能力与肥胖的生理病理学高度相关，并与治疗策略有关。
