Rösch Christiane, Taverne Nico, Venema Koen, Gruppen Harry, Wells Jerry M, Schols Henk A
Laboratory of Food Chemistry, Wageningen University, Wageningen, the Netherlands.
Top Institute Food and Nutrition, Wageningen, the Netherlands.
Mol Nutr Food Res. 2017 Jan;61(1). doi: 10.1002/mnfr.201600243. Epub 2016 Aug 11.
This study simulates the fermentation process of barley β-glucan and sugar beet pectin in the human colon and monitors the degradation products formed. Additionally, immune effects of the degradation products were investigated.
Immunostimulatory activity of fermentation digesta was investigated using bone marrow derived dendritic cells (BMDCs) from toll-like receptor 2/4 (TLR2/4) knockout mice, which were unresponsive to microbe-associated molecular patterns. Cytokine responses were elicited to dietary fibers and not to the SCFA and microbiota. The fermentation digesta were analyzed for their SCFA profiles and glycan metabolites over time. During fermentation the amount of insoluble precipitating fibers increased and induced as well as soluble molecules of lower molecular mass greater amounts of cytokines in BMDCs than the parental fiber. Additionally, high amounts of cytokines can be attributed to soluble galactose-rich beet pectin molecules.
The fermentation of the two fibers led to fiber-specific amounts of SCFA, glycosidic metabolites, and different immunomodulatory properties. BMDC from TLR2/4 knockout mice did not respond to the digest microbiota and SCFA, making it a useful approach to study temporal effects of fermentation on the immunomodulatory effects of fibers.
本研究模拟了大麦β-葡聚糖和甜菜果胶在人体结肠中的发酵过程，并监测所形成的降解产物。此外，还研究了降解产物的免疫效应。
使用来自 toll 样受体 2/4（TLR2/4）基因敲除小鼠的骨髓源性树突状细胞（BMDC）研究发酵消化物的免疫刺激活性，这些小鼠对微生物相关分子模式无反应。细胞因子反应是由膳食纤维引发的，而非短链脂肪酸（SCFA）和微生物群。随着时间的推移，对发酵消化物的 SCFA 谱和聚糖代谢产物进行了分析。在发酵过程中，不溶性沉淀纤维的量增加，并且与原始纤维相比，诱导了更多的细胞因子，以及较低分子量的可溶性分子在 BMDC 中诱导产生了更多的细胞因子。此外，大量的细胞因子可归因于富含可溶性半乳糖的甜菜果胶分子。
两种纤维的发酵导致了特定纤维量的 SCFA、糖苷代谢产物以及不同的免疫调节特性。来自 TLR2/4 基因敲除小鼠的 BMDC 对消化微生物群和 SCFA 无反应，这使其成为研究发酵对纤维免疫调节作用的时间效应的有用方法。
