Hietaniemi M, Jokela M, Rantala M, Ukkola O, Vuoristo J T, Ilves M, Rysä J, Kesäniemi Y
Department of Internal Medicine, University of Oulu, Oulu, Finland.
Nutr Metab Cardiovasc Dis. 2009 Mar;19(3):177-83. doi: 10.1016/j.numecd.2008.06.009. Epub 2008 Sep 19.
Most gene expression studies examining the effect of obesity and weight loss have been performed using adipose tissue. However, the liver also plays a central role in maintaining energy balance. We wanted to study the effects of a hypocaloric diet on overall hepatic gene expression and metabolic risk factors.
The study subjects were middle-aged, obese women. The diet intervention subjects (n=12) were on a hypocaloric, low-fat diet for 8 weeks with a daily energy intake of 5.0 MJ (1200 kcal), while the control subjects (n=19) maintained their weight. Liver biopsies were taken at the end of the diet period during a gallbladder operation. Hepatic gene expression was analyzed using microarrays by comparing the gene expression profiles from four subjects per group. A global decrease in gene expression was observed with 142 down-regulated genes and only one up-regulated gene in the diet intervention group. The diet resulted in a mean weight loss of 5% of body weight. Triglyceride and fasting insulin concentrations decreased significantly after the diet.
The global decrease in hepatic gene expression was unexpected but the results are interesting, since they included several genes not previously linked to weight reduction. However, since the comparison was made only after the weight reduction, other factors in addition to weight loss may also have been involved in the differences in gene expression between the groups. The decrease in triglyceride and fasting plasma insulin concentrations is in accordance with results from previous weight-loss studies.
大多数研究肥胖及体重减轻影响的基因表达研究都是在脂肪组织中进行的。然而，肝脏在维持能量平衡方面也起着核心作用。我们希望研究低热量饮食对肝脏整体基因表达及代谢风险因素的影响。
研究对象为中年肥胖女性。饮食干预组（n = 12）采用低热量、低脂饮食，持续8周，每日能量摄入为5.0兆焦耳（1200千卡），而对照组（n = 19）维持体重不变。在饮食期结束时，于胆囊手术期间采集肝脏活检样本。通过比较每组4名受试者的基因表达谱，利用微阵列分析肝脏基因表达。在饮食干预组中观察到基因表达整体下降，有142个基因下调，仅有1个基因上调。该饮食导致体重平均减轻了5%。饮食后甘油三酯和空腹胰岛素浓度显著降低。
肝脏基因表达的整体下降出乎意料，但结果很有趣，因为其中包括一些先前未与体重减轻相关联的基因。然而，由于仅在体重减轻后进行比较，除体重减轻外的其他因素可能也参与了两组间基因表达的差异。甘油三酯和空腹血浆胰岛素浓度的降低与先前减肥研究的结果一致。
