Department of Pathology and Laboratory Medicine, Metabolic Disease Institute, University of Cincinnati , Cincinnati, Ohio.
Discovery and Product Research and Development, Abbott Nutrition, Abbott Laboratories , Columbus, Ohio.
Am J Physiol Gastrointest Liver Physiol. 2018 Jul 1;315(1):G95-G103. doi: 10.1152/ajpgi.00236.2017. Epub 2018 Feb 22.
Breast milk lutein is better absorbed by infants than lutein delivered in infant formula. Therefore, we wanted to better understand the possible absorption differences of lutein in breast milk vs. that in infant formula by determining its bioavailability after gastric administration and whether the intestinal absorption of lutein can be improved by using new delivery vehicles. Study 1 compared the intestinal uptake,and the lymphatic and portal transport of lutein in conscious lymph fistula rats. Four groups of lymph- and portal vein-cannulated rats ( n = 8-10/group) were randomized to receive via gastric tube increasing doses (10, 20, 40, or 80 mg/kg) of 20% lutein in safflower oil (SO) suspension to assess whether there was a saturable level of lutein that could be absorbed and transported in lymph. Aliquots of hourly portal blood and lymph were taken for lutein and zeaxanthin analyses. The dose-response study showed that 20 mg/kg lutein was the saturable level of lymphatic lutein absorption with no lutein detected in portal circulation at any dosage level tested. Study 2 randomized five groups of lymph fistula rats ( n = 4-9/group) to receive 20 mg/kg lutein from either lutein in SO or lutein in four different mono- and diglyceride oils (MDGs). Gastric infusion of lutein suspended in MDG (20 mg/kg) significantly improved (71-211%, P < 0.05) lymphatic lutein output 2-6 h after lipid feeding vs. lutein in SO. Lymphatic zeaxanthin (10% of the lutein fed mixture) transport in both Study 1 and Study 2 followed that of lutein. We conclude that a mixture of MDGs helps solubilize lutein and facilitate gastrointestinal micelle formation, thus improving lymphatic lutein absorption compared with triglyceride oils. NEW & NOTEWORTHY This paper describes how lutein is digested and absorbed by the gastrointestinal tract by using the conscious lymph fistula rat model. Our dose-response study showed that absorption and lymphatic transport of lutein is a saturable process with no lutein detected in portal circulation at any dosage level tested. Our paper also provides insight into how this process can be improved by modifying the typical lipid mixtures carrying the lutein.
母乳中的叶黄素比婴儿配方奶粉中的叶黄素更容易被婴儿吸收。因此，我们希望通过确定胃给药后叶黄素的生物利用度，以及通过使用新的递送载体是否可以改善叶黄素的肠道吸收，来更好地了解母乳与婴儿配方奶粉中叶黄素的可能吸收差异。研究 1 比较了清醒的淋巴瘘大鼠中叶黄素在肠道中的摄取、淋巴和门静脉的转运。将四组淋巴管和门静脉插管的大鼠（n = 8-10/组）随机分为通过胃管给予 20%红花油（SO）悬浮液中递增剂量（10、20、40 或 80 mg/kg）的叶黄素，以评估是否存在可吸收和转运淋巴的叶黄素饱和水平。每小时取门静脉血和淋巴样液的等分试样进行叶黄素和玉米黄质分析。剂量反应研究表明，20 mg/kg 叶黄素是肠道叶黄素吸收的饱和水平，在任何测试剂量水平下，门静脉循环中均未检测到叶黄素。研究 2 将五组淋巴瘘大鼠（n = 4-9/组）随机分为接受来自 SO 中的叶黄素或四种不同的单甘油脂（MDG）中的叶黄素的 20 mg/kg 的五个组。在脂质喂养后 2-6 小时，与 SO 中的叶黄素相比，胃内输注悬浮在 MDG 中的叶黄素（20 mg/kg）显著增加（71-211%，P < 0.05）淋巴叶黄素的输出。在研究 1 和研究 2 中，叶黄素的转运都伴随着叶黄素的转运。我们得出的结论是，MDG 的混合物有助于溶解叶黄素并促进胃肠道胶束的形成，从而与甘油三酯油相比，改善了肠道叶黄素的吸收。新的和值得注意的是，本文描述了利用清醒的淋巴瘘大鼠模型，叶黄素如何被胃肠道消化和吸收。我们的剂量反应研究表明，叶黄素的吸收和淋巴转运是一个饱和过程，在任何测试剂量水平下，门静脉循环中均未检测到叶黄素。我们的论文还提供了如何通过修饰携带叶黄素的典型脂质混合物来改善这一过程的见解。
