Department of Nutritional Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
Core Facility Computational Bioanalytics, Medical University of Graz, 8010 Graz, Austria.
Nutrients. 2021 Oct 26;13(11):3807. doi: 10.3390/nu13113807.
The capacity of microbiota to produce medium-chain fatty acids (MCFA) and related consequences for the gastrointestinal (GI) tract have never been reported before. We verified the impact of nutrition-related factors on fatty acid (FAs) production and found that caloric restriction decreased levels of most of MCFAs in the mouse cecum, whereas overnight fasting reduced the levels of acetate and butyrate but increased propionate and laurate. A diet high in soluble fibre boosted the production of short-chain fatty acids (SCFA) and caproate whereas a high-cellulose diet did not have an effect or decreased the levels of some of the FAs. Rectal infusion of caprylate resulted in its rapid metabolism for energy production. Repeated 10-day MCFA infusion impacted epididymal white adipose tissue (eWAT) weight and lipid accumulation. Repeated infusion of caprylate rectally tended to increase the concentration of active ghrelin in mice plasma; however, this increase was not statistically significant. In Caco-2 cells, caprylate increased the expression of Fabp2, Pdk4, Tlr3, and Gpr40 genes as well as counteracted TNFα-triggered downregulation of Pparγ, Occludin, and Zonulin mRNA expression. In conclusion, we show that colonic MCFAs can be rapidly utilized as a source of energy or stored as a lipid supply. Further, locally produced caprylate may impact metabolism and inflammatory parameters in the colon.
微生物群产生中链脂肪酸（MCFA）的能力及其对胃肠道（GI）的相关影响以前从未有过报道。我们验证了与营养相关的因素对脂肪酸（FA）产生的影响，发现热量限制降低了小鼠盲肠中大多数 MCFA 的水平，而 overnight fasting 降低了乙酸盐和丁酸盐的水平，但增加了丙酸盐和月桂酸盐的水平。高可溶性纤维的饮食促进了短链脂肪酸（SCFA）和己酸盐的产生，而高纤维素饮食没有影响或降低了一些 FA 的水平。癸酸盐直肠输注导致其迅速代谢以产生能量。重复 10 天的 MCFA 输注会影响附睾白色脂肪组织（eWAT）的重量和脂质积累。重复直肠输注癸酸盐可能会增加小鼠血浆中活性胃饥饿素的浓度；然而，这种增加并不具有统计学意义。在 Caco-2 细胞中，癸酸盐增加了 Fabp2、Pdk4、Tlr3 和 Gpr40 基因的表达，并抵消了 TNFα 触发的 Pparγ、Occludin 和 Zonulin mRNA 表达的下调。总之，我们表明结肠中的 MCFAs 可以迅速用作能量来源或储存为脂质供应。此外，局部产生的癸酸盐可能会影响结肠中的代谢和炎症参数。
