Center for Human Nutrition, Washington University School of Medicine, St Louis, MO 63110, USA.
Diabetes Obes Metab. 2010 Jul;12(7):584-90. doi: 10.1111/j.1463-1326.2009.01191.x.
Although weight loss usually decreases very-low-density lipoprotein-triglyceride (VLDL-TG) secretion rate, the change in VLDL-TG kinetics is not directly related to the change in body weight. Circulating leptin also declines with weight loss and can affect hepatic lipid metabolism. The aim of this study was to determine whether circulating leptin is associated with weight loss-induced changes in VLDL-TG secretion.
Ten extremely obese subjects were studied. VLDL-TG secretion rate and the contribution of systemic (derived from lipolysis of subcutaneous adipose tissue TG) and non-systemic fatty acids (derived primarily from lipolysis of intrahepatic and intraperitoneal TG, and de novo lipogenesis) to VLDL-TG production were determined by using stable isotopically labelled tracer methods before and 1 year after gastric bypass surgery.
Subjects lost 33 +/- 12% of body weight, and VLDL-TG secretion rate decreased by 46 +/- 23% (p = 0.001), primarily because of a decrease in the secretion of VLDL-TG from non-systemic fatty acids (p = 0.002). Changes in VLDL-TG secretion rates were not significantly related to reductions in body weight, body mass index, plasma palmitate flux, free fatty acid or insulin concentrations. The change in VLDL-TG secretion was inversely correlated with the change in plasma leptin concentration (r = -0.72, p = 0.013), because of a negative association between changes in leptin and VLDL-TG secretion from non-systemic fatty acids (r = -0.95, p < 0.001).
Weight loss-induced changes in plasma leptin concentration are inversely associated with changes in VLDL-TG secretion rate. Additional studies are needed to determine whether the correlation between circulating leptin and VLDL-TG secretion represents a cause-and-effect relationship.
尽管体重减轻通常会降低极低密度脂蛋白-甘油三酯（VLDL-TG）的分泌率，但 VLDL-TG 动力学的变化与体重的变化并不直接相关。循环瘦素也随着体重减轻而下降，并能影响肝脏的脂质代谢。本研究旨在确定循环瘦素是否与体重减轻引起的 VLDL-TG 分泌变化有关。
对 10 名极度肥胖的患者进行了研究。使用稳定同位素标记示踪剂方法，在胃旁路手术后 1 年前和 1 年后，分别测定了 VLDL-TG 分泌率以及全身（来源于皮下脂肪组织 TG 的脂解）和非全身脂肪酸（主要来源于肝内和腹腔内 TG 的脂解以及从头合成）对 VLDL-TG 生成的贡献。
患者体重减轻了 33 +/- 12%，VLDL-TG 分泌率下降了 46 +/- 23%（p = 0.001），主要是由于非全身脂肪酸的 VLDL-TG 分泌减少（p = 0.002）。VLDL-TG 分泌率的变化与体重、体重指数、血浆棕榈酸流量、游离脂肪酸或胰岛素浓度的降低没有显著关系。VLDL-TG 分泌的变化与血浆瘦素浓度的变化呈负相关（r = -0.72，p = 0.013），因为瘦素和非全身脂肪酸的 VLDL-TG 分泌之间存在负相关（r = -0.95，p < 0.001）。
体重减轻引起的血浆瘦素浓度变化与 VLDL-TG 分泌率的变化呈负相关。需要进一步的研究来确定循环瘦素与 VLDL-TG 分泌之间的相关性是否代表因果关系。
