Department of Internal Medicine, Division of Gastroenterology-Hepatology, School of Nutrition & Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.
Department of Internal Medicine, Division of Gastroenterology-Hepatology, School of Nutrition & Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.
Clin Nutr. 2018 Apr;37(2):471-480. doi: 10.1016/j.clnu.2017.01.024. Epub 2017 Feb 3.
BACKGROUND & AIMS: Obesity and metabolic diseases are associated with alterations in microbial composition and impaired gut barrier. Previous in vitro and animal studies have shown that arabinoxylans (AX) have the potential to modulate gut microbiota and gut barrier and therefore could have a protective role. Primary aim of the study was to investigate the effect of AX on intestinal permeability. Secondary aims included the effect of AX on gene transcription and protein expression of tight junctions (TJ), intestinal microbiota composition and activity, immune response and metabolic markers in overweight and obese individuals.
In this randomized, double-blind, placebo-controlled trial, 47 overweight subjects were randomly assigned to groups receiving 7.5 g/d AX (n = 16), 15 g/d AX (n = 17) or 15 g/d placebo (n = 14) for 6 wks. Intestinal permeability was investigated using a multi-sugar test. Sigmoid colon tissue was obtained from a subgroup (n = 26) for analyzing gene transcription and mucosal expression of TJ proteins. Fecal samples were collected to assess microbial composition and activity. Furthermore, the production of cytokines by stimulated peripheral blood mononuclear cells (PBMCs) was examined. Blood was also sampled for measuring metabolic markers.
No significant changes in gastrointestinal permeability and TJ protein expression were observed after 6 wks AX supplementation compared to placebo. However, gene transcription of occludin was upregulated in the 7.5 g AX group, and transcription of claudin-3 and claudin-4 were upregulated in the 15 g AX group compared to placebo. Furthermore, fecal microbiota diversity was decreased after 6 wks 15 g AX treatment, but no change in relative abundance of dominant phyla was observed. AX intake significantly decreased fecal pH and increased fecal concentrations of total SCFAs, acetate, propionate and butyrate, compared to placebo. Additionally, a decreased TNFα production by stimulated PBMCs was observed after 15 g AX treatment. No changes in metabolic markers were detected.
Regular consumption of AX resulted in a more beneficial fermentation profile in overweight and obese individuals. Further studies are required to assess whether such fermentation profile will translate into improved gut barrier function and immune health. The trial has been registered at ClinicalTrials.gov with study ID number NCT01877044.
肥胖和代谢性疾病与微生物组成的改变和肠道屏障受损有关。先前的体外和动物研究表明，阿拉伯木聚糖（AX）具有调节肠道微生物群和肠道屏障的潜力，因此可能具有保护作用。本研究的主要目的是研究 AX 对肠道通透性的影响。次要目的包括 AX 对超重和肥胖个体的紧密连接（TJ）基因转录和蛋白表达、肠道微生物组成和活性、免疫反应和代谢标志物的影响。
在这项随机、双盲、安慰剂对照试验中，47 名超重受试者被随机分为三组，分别接受 7.5 g/d AX（n=16）、15 g/d AX（n=17）或 15 g/d 安慰剂（n=14）治疗 6 周。使用多糖试验检测肠道通透性。从小样本（n=26）中获取乙状结肠组织，分析 TJ 蛋白的基因转录和黏膜表达。收集粪便样本以评估微生物组成和活性。此外，还检测了刺激外周血单核细胞（PBMCs）产生的细胞因子。还抽取血液以测量代谢标志物。
与安慰剂相比，AX 补充 6 周后，胃肠道通透性和 TJ 蛋白表达没有明显变化。然而，与安慰剂相比，7.5 g AX 组的紧密连接蛋白-1 基因转录上调，15 g AX 组的 Claudin-3 和 Claudin-4 基因转录上调。此外，15 g AX 治疗 6 周后，粪便微生物多样性减少，但主要菌群的相对丰度没有变化。与安慰剂相比，AX 摄入可显著降低粪便 pH 值，并增加粪便中总 SCFA、乙酸盐、丙酸盐和丁酸盐的浓度。此外，15 g AX 治疗后，刺激 PBMCs 产生的 TNFα 减少。未检测到代谢标志物的变化。
经常食用 AX 可使超重和肥胖个体的发酵谱更有益。需要进一步的研究来评估这种发酵谱是否会转化为改善肠道屏障功能和免疫健康。该试验已在 ClinicalTrials.gov 上注册，研究 ID 号为 NCT01877044。
