Fain J N, Buehrer B, Tichansky D S, Madan A K
Department of Molecular Sciences, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 3816, USA.
Int J Obes (Lond). 2008 Mar;32(3):429-35. doi: 10.1038/sj.ijo.0803745. Epub 2007 Sep 25.
Adiponectin is an adipokine produced by adipose tissue. The present studies examined the in vitro release of adiponectin by human omental adipose tissue explants as well as the mRNA content of freshly isolated non-fat cells and adipocytes plus cultured preadipocytes and adipocytes derived from omental fat.
The release of adiponectin was reduced while that of interleukin-8 (IL-8) was enhanced in tissue explants from morbidly obese women. The release of adiponectin was also reduced by one-third in explants from morbidly obese diabetic women while that of IL-8 was unaffected by diabetes. The release of adiponectin was enhanced by insulin and by inhibition of endogenous tumor necrosis factor (TNFalpha) using etancercept. Adiponectin was released in appreciable amounts by the undigested matrix obtained by collagenase digestion of adipose tissue. The release of adiponectin by non-fat cells (matrix+SV cells) was comparable to that by the adipocytes derived from the same amount of tissue while the adiponectin mRNA content of the pooled matrix and SV cell fractions was 40% of that in intact tissue. The adiponectin mRNA content was 48-fold greater in isolated adipocytes than in non-fat cells derived from adipose tissue. In contrast, the amount of adiponectin mRNA in vitro differentiated omental adipocytes was 1 x l0(6)-fold greater than that in cultured preadipocytes while that of leptin was 3 x 10(4)-fold greater.
Adiponectin mRNA is present in the non-fat cells of freshly isolated adipose tissue and release by the non-fat cells derived from a gram of adipose tissue is comparable to that by adipocytes isolated from the same amount of tissue. While leptin is only released by mature adipocytes, adiponectin is released by both the non-fat cells and the fat cells derived from human omental adipose tissue.
脂联素是一种由脂肪组织产生的脂肪因子。本研究检测了人网膜脂肪组织外植体中脂联素的体外释放情况，以及新鲜分离的非脂肪细胞和脂肪细胞，加上培养的前脂肪细胞和来自网膜脂肪的脂肪细胞中的mRNA含量。
病态肥胖女性组织外植体中脂联素的释放减少，而白细胞介素-8（IL-8）的释放增加。病态肥胖糖尿病女性外植体中脂联素的释放也减少了三分之一，而IL-8的释放不受糖尿病影响。胰岛素和使用依那西普抑制内源性肿瘤坏死因子（TNFα）可增强脂联素的释放。脂肪组织经胶原酶消化得到的未消化基质可释放出相当数量的脂联素。非脂肪细胞（基质+SV细胞）释放的脂联素与来自相同量组织的脂肪细胞释放的脂联素相当，但合并后的基质和SV细胞组分中的脂联素mRNA含量仅为完整组织中的40%。分离出的脂肪细胞中的脂联素mRNA含量比来自脂肪组织的非脂肪细胞高48倍。相比之下，体外分化的网膜脂肪细胞中的脂联素mRNA量比培养的前脂肪细胞中的高1×10⁶倍，而瘦素的则高3×10⁴倍。
脂联素mRNA存在于新鲜分离的脂肪组织的非脂肪细胞中，来自一克脂肪组织的非脂肪细胞释放的脂联素与从相同量组织中分离出的脂肪细胞释放的脂联素相当。虽然瘦素仅由成熟脂肪细胞释放，但脂联素可由人网膜脂肪组织来源的非脂肪细胞和脂肪细胞释放。
