Gunness Purnima, Michiels Joris, Vanhaecke Lynn, De Smet Stefaan, Kravchuk Olena, Van de Meene Allison, Gidley Michael J
Australian Research Council Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland, Australia;
Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
FASEB J. 2016 Dec;30(12):4227-4238. doi: 10.1096/fj.201600465R. Epub 2016 Sep 14.
Although oat (1,3:1,4)-β-glucan (BG) has been shown to decrease blood cholesterol in intervention trials, the detailed mechanism is not yet defined, but restricted reabsorption of bile acids (BAs) has been hypothesized. Using pigs as a model for humans we demonstrated that, compared to the control, BG added to the diet for 26 d caused decreases of 24% in blood total BAs (TBAs), 34% in total cholesterol (TC), and 57% in LDL cholesterol (LDL-C) (P < 0.01); decreases of 20% TBA in the midjejunum and terminal ileum (P < 0.01); increases of 80% in cecal total neutral sterols (TNSs) including cholesterol (P < 0.01); a 50% reduction in BA active transport across ex vivo ileum after 40 min (P < 0.001); and 32% decrease in jejunal microvillus heights with apparent increased goblet cell activity. The results suggest that BG not only physically hinders the active reabsorption of BAs and uptake of cholesterol, but also changes the BAs profile with lower circulating levels without excess excretion in the feces, thus resulting in reduced blood TC and LDL-C. Fermentation of sterols reaching the colon enhanced production of therapeutic ursodeoxycholic acid, suppressed toxic lithocholic acid, and decreased the possibility of cholesterol absorption by transforming the latter into coprostanol, a nonabsorbable NS.-Gunness, P., Michiels, J., Vanhaecke, L., De Smet, S., Kravchuk, O., Van de Meene, A., Gidley, M. J. Reduction in circulating bile acid and restricted diffusion across the intestinal epithelium are associated with a decrease in blood cholesterol in the presence of oat β-glucan.
尽管在干预试验中已表明燕麦（1,3:1,4）-β-葡聚糖（BG）可降低血液胆固醇，但详细机制尚未明确，不过已有胆汁酸（BAs）重吸收受限的假说。我们以猪作为人类模型，证明与对照组相比，在饮食中添加BG 26天可使血液总胆汁酸（TBAs）降低24%、总胆固醇（TC）降低34%、低密度脂蛋白胆固醇（LDL-C）降低57%（P<0.01）；空肠中段和回肠末端的TBA降低20%（P<0.01）；盲肠总中性固醇（TNSs，包括胆固醇）增加80%（P<0.01）；40分钟后离体回肠的胆汁酸主动转运减少50%（P<0.001）；空肠微绒毛高度降低32%，杯状细胞活性明显增加。结果表明，BG不仅在物理上阻碍胆汁酸的主动重吸收和胆固醇的摄取，并能改变胆汁酸谱，使循环水平降低且粪便中无过多排泄，从而降低血液中的TC和LDL-C。到达结肠的固醇发酵增强了治疗性熊去氧胆酸的生成，抑制了有毒的石胆酸，并通过将胆固醇转化为不可吸收的中性固醇粪甾烷醇降低了胆固醇吸收的可能性。-冈尼斯，P.，米歇尔斯，J.，万哈克，L.，德·斯梅特，S.，克拉夫丘克，O.，范德梅内，A.，吉德利，M.J. 燕麦β-葡聚糖存在时循环胆汁酸的减少和跨肠上皮的扩散受限与血液胆固醇的降低有关。
