Cardiovascular and Mass Spectrometry Laboratories, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA (J.R.-M., J.G., G.G.D., A.H.L., N.R.M.).
Integrative Pharmacology and Systems Neuroscience Research Group, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain (J.R.-M.).
Arterioscler Thromb Vasc Biol. 2020 Dec;40(12):2953-2964. doi: 10.1161/ATVBAHA.120.315260. Epub 2020 Oct 1.
Compare the postprandial fatty acid metabolism of isotopically labeled stearate (U-C18:0) and oleate (U-C18:1). Approach and Results: In conjunction with a randomized-controlled crossover trial, 6 hypercholesterolemic postmenopausal women (≥50 years; body mass index: 25.6±3.0 kg/m; LDL [low-density lipoprotein]-cholesterol ≥110 mg/dL) consumed isocaloric diets enriched in 18:0 or 18:1 (10%-15% E) for 5 weeks each. On day 1 of week 5, following a 12-hour fast, participants receive their experimental diet divided into 13 hourly meals beginning at 8 am. U-C18:0 or U-C18:1 was incorporated into the 1:00 pm meal (1.0 mg/kg body weight). Serial blood and breath samples were collected over 12 hours and fasting samples at 24 and 48 hours. Plasma and lipid subfraction fatty acid profiles were assessed by gas chromatography-flame ionization detector, isotope-enrichment by liquid chromatography time-of-flight mass spectrometry, and fatty acid oxidation rate (expired CO) by isotope ratio mass spectrometry. Both diets resulted in similar plasma LDL-cholesterol concentrations. Kinetic curves showed that U-C18:0 had a higher plasma area under the curve (66%), lower plasma clearance rate (-46%), and a lower cumulative oxidation rate (-34%) than U-C18:1. Three labeled plasma metabolites of U-C18:0 were detected: C16:0, C16:1, and C18:1. No plasma metabolites of U-C18:1 were detected within the study time-frame. Higher incorporation of 18:0 in cholesteryl ester and triglyceride fractions was observed on the 18:0 compared with the 18:1 diet.
The neutrality of 18:0 on plasma LDL-cholesterol concentrations is not attributable to a single factor. Compared with 18:1, 18:0 had higher plasma area under the curve because of lower clearance and oxidation rates, underwent both a direct and a multistage conversion to 18:1, and was preferentially incorporated into cholesteryl esters and triglycerides.
比较同位素标记硬脂酸（U-C18:0）和油酸（U-C18:1）的餐后脂肪酸代谢。方法和结果：在一项随机对照交叉试验中，6 名绝经后高胆固醇血症妇女（≥50 岁；体重指数：25.6±3.0 kg/m；LDL[低密度脂蛋白]-胆固醇≥110mg/dL）分别接受富含 18:0 或 18:1（10%-15%E）的等热量饮食 5 周。在第 5 周的第 1 天，禁食 12 小时后，参与者在上午 8 点开始接受他们的实验饮食，分成 13 份，每小时一份。U-C18:0 或 U-C18:1 被掺入下午 1 点的膳食（1.0mg/kg 体重）。在 12 小时内采集连续的血液和呼吸样本，并在 24 小时和 48 小时采集禁食样本。通过气相色谱-火焰离子化检测器评估血浆和脂质亚组分脂肪酸谱，通过液相色谱-飞行时间质谱仪评估同位素丰度，通过同位素质谱法评估脂肪酸氧化率（呼出 CO）。两种饮食均导致相似的血浆 LDL-胆固醇浓度。动力学曲线显示，U-C18:0 的血浆曲线下面积较高（66%），血浆清除率较低（-46%），累积氧化率较低（-34%），而 U-C18:1 则较低。检测到 U-C18:0 的三种标记血浆代谢物：C16:0、C16:1 和 C18:1。在研究时间范围内未检测到 U-C18:1 的血浆代谢物。与 18:1 饮食相比，在 18:0 饮食中观察到胆固醇酯和甘油三酯分数中 18:0 的更高掺入。结论：18:0 对血浆 LDL-胆固醇浓度的中性不是归因于单一因素。与 18:1 相比，18:0 的血浆曲线下面积较高，因为清除率和氧化率较低，直接和多阶段转化为 18:1，并且优先掺入胆固醇酯和甘油三酯。
