Shiseido Research Center, Yokohama-shi, Kanagawa, Japan. tomonobu.ezure@ to.shiseido.co.jp
Exp Dermatol. 2010 Oct;19(10):878-82. doi: 10.1111/j.1600-0625.2009.00970.x.
Increment of subcutaneous adipose tissue is a risk factor for facial morphological changes, such as sagging, which may be at least partly because of the increased weight burden of accumulated fat. However, it is not clear how the increase of subcutaneous adipose tissue affects dermal structure and function. We examined this issue in HR-1 hairless mice given a high-fat diet (HFD). After having been fed with HFD for 12 weeks, the mice became obese and the subcutaneous adipose tissue layer was significantly thickened, while the dermal layer became significantly thinner than that of control mice fed normal diet. However, the thickness of the dermal layer was not changed in the ear pinna, which lacks a subcutaneous adipose layer, suggesting that increase of subcutaneous adipose tissue may induce dermal changes. The number of dermal fibroblasts in the dermis was significantly reduced in obese mice, although there was no change in gene expression levels of extracellular matrix components, including collagen, hyaluronic acid synthase, fibulin5, fibrillin-1, laminin β1, matrix metalloproteinases and tissue inhibitor of metalloproteinases. Dermal elasticity was significantly decreased in obese hairless mice. These results suggest that subcutaneous adipose cells in obese mice may reduce the proliferation of dermal fibroblasts and induce a decrease of dermal thickness and elasticity. Therefore, the increment of the subcutaneous adipose layer in obese subjects may induce impairment of dermal biomechanical characteristics and promote the appearance of sagging.
皮下脂肪组织的增加是面部形态变化（如下垂）的一个风险因素，这可能至少部分是因为积累的脂肪增加了体重负担。然而，皮下脂肪组织的增加如何影响皮肤结构和功能尚不清楚。我们在给予高脂肪饮食（HFD）的 HR-1 无毛小鼠中研究了这个问题。经过 12 周的 HFD 喂养，小鼠变得肥胖，皮下脂肪组织层明显增厚，而真皮层比正常饮食喂养的对照小鼠明显变薄。然而，缺乏皮下脂肪层的耳部耳甲，其真皮层厚度没有变化，这表明皮下脂肪组织的增加可能会引起皮肤变化。肥胖小鼠真皮中的真皮成纤维细胞数量明显减少，尽管细胞外基质成分（包括胶原、透明质酸合酶、纤维连接蛋白 5、原纤维蛋白 1、层粘连蛋白 β1、基质金属蛋白酶和金属蛋白酶组织抑制剂）的基因表达水平没有变化。肥胖无毛小鼠的皮肤弹性显著降低。这些结果表明，肥胖小鼠的皮下脂肪细胞可能会减少真皮成纤维细胞的增殖，并导致真皮厚度和弹性降低。因此，肥胖患者皮下脂肪层的增加可能会损害皮肤的生物力学特性，并促进下垂的出现。
