微生态制剂调节便秘、腹泻人群肠道菌群结构与产短链脂肪酸关键菌属的相关性

为探究微生态制剂对健康、便秘和腹泻人群肠道菌群结构的调节能力。本研究以健康、便秘和腹泻人群 为对象,令其定时、定量摄入水苏糖（stachyose tetrahydrate,Sta）、益生菌纯粉（probiotics power,PP）、益生 菌剂（probotic preparations,PPrs）3 种微生态制剂,共6 周,采集新鲜粪便样本并提取DNA,利用Ion torrent PGM 二代测序技术进行16S rRNA V3区扩增子测序,并用气相色谱检测粪便中的短链脂肪酸（short-chain fatty acids, SCFAs）表达水平,最后联合多变量统计学分析方法对测序数据进行多样性分析。结果表明：绝大多数序列属 于硬壁菌门（Firmicutes）和拟杆菌门（Bacteroidetes）,约占总序列数的94.37%。随着微生态制剂的摄入,受 试人群肠道菌群的群落结构多样性明显增加,毛螺菌科（Lachnospiraceae）中的Blautia、Lachnospira以及瘤胃菌 科（Ruminococcaceae）中的Faecalibacterium、Oscillospir等与产SCFAs相关的菌属都明显地增长,其中Blautia和 Faecalibacterium与SCFAs含量呈显著正相关。SCFAs的含量以及肠道中相应菌群的增长与减少都与微生态制剂的成 分相关,在3 组受试人群中,服用Sta组,丙酸含量显著增加,乙酸与丁酸含量也在2 周左右有所增加,并伴随产 SCFAs的菌属快速且大量增长;PP组肠道中只有乙酸含量有所增加,丙酸和丁酸含量呈现降低的趋势,而产SCFAs 的菌属增长较明显;服用PPrs组,乙酸和丁酸含量明显增加,且便秘和腹泻人群在停止服用后,其SCFAs的含量 接近于健康人群,常见的Bifidobacterium、Lactobacillus、Parabacteroides等外源性益生菌均明显增长,可能性致病 菌相对丰度降低,表明服用PPrs对肠道菌群结构的调节作用以及影响更大。此外,根据肠型的分析,Bacteroides和 Prevotella在饮食的共同驱动下会调整并改变肠型,而仅通过所选择的微生态制剂的作用,在驱动肠型改变方面不 显著。综上所述,肠道疾病状态的人群服用微生态制剂后,肠道菌群结构向正常人群的状态调整,菌群多样性和 SCFAs表达水平提高,表现出持续抑制肠道有害细菌生长,促进有益菌的增殖,以此来维持肠道菌群结构的稳态。 经扩增子测序分析获得初步结论为：微生态制剂有改变腹泻、便秘人群肠道菌群整体结构的功效,并且PPrs要比单 一的Sta或PP调整肠道菌群的能力更突出。     

Sialoglycoprotein isolated from Carassius auratus eggs promotes osteoblast differentiation via targeting the p38 mitogen‐activated protein kinase‐dependent Wnt/β‐catenin and BMP2/Smads pathways

In the current study, sialoglycoprotein isolated from eggs of Carassius auratus promoted MC3T3‐E1 cells proliferation and differentiation, as assessed by MTT, mineralized nodule formation in vitro, as well as new osteoid formation in neonatal mouse calvarias ex vivo. Further research revealed that Ca‐SGP facilitated osteogenesis via activating BMP2/Smads, Wnt/β‐catenin, and p38MAPK signaling pathways. What is more, p38MAPK inhibitor SB203580 down‐regulated related mRNA and protein expression of BMP2/Smads and Wnt/β‐catenin signaling pathways, suggesting that p38MAPK pathway might be important for activation of BMP2/Smads and Wnt/β‐catenin pathways in Ca‐SGP‐induced osteoblastic differentiation. In conclusion, it was demonstrated that Ca‐SGP promotes osteoblasts differentiation via activating p38MAPK‐dependent BMP2/Smads and Wnt/β‐catenin signaling pathways, which may provide basis for the use of Ca‐SGP as a potential agent to treat bone loss‐associated diseases such as osteoporosis.

Practical application

Carassius auratus eggs are one of the major by‐products during fish processing and contain sialoglycoprotein which plays an important role in biological functions. However, they have not been high‐value utilized. This study demonstrated that Sialoglycoprotein isolated from eggs of C. auratus (Ca‐SGP) promoted MC3T3‐E1 cells proliferation, differentiation and mineralized nodule formation in vitro, as well as neonatal mouse calvarias formation ex vivo, which may provide basis for a novel application of C. auratus eggs as a functional food used to accelerate bone formation.     

Dietary polysaccharide from Mung bean [Vigna radiate (Linn.) Wilczek] skin modulates gut microbiota and short-chain fatty acids in mice

Cumulative evidence revealed that the gut microbiota play important role in human health. Polysaccharide from Mung bean [Vigna radiate (Linn.) Wilczek] skin has been confirmed to have a variety of biological activities, but its effect on the gut microbiota has not been considered. This study aimed to investigate the effect of hot water extraction of mung bean skin water-soluble polysaccharides (MBP-2) on the gut microbiota of Balb/c mice and its main metabolite short-chain fatty acids (SCFAs). The results showed that supplementation with MBP-2 increased the colon length and the production of SCFAs in Balb/c mice, and improved the intestinal microenvironment by producing SCFAs, which is beneficial to the intestinal health of mice. MBP-2 increased the Chao1 index and ACE index in a dose-depended manner, and changed the structure of the gut microbiota and significantly promoted the growth of probiotic bacteria in Balb/c mice. The faecal bacterial flora of mice is mainly composed of nine phyla and twenty-seven genera, MBP-2 can regulate the composition of intestinal flora by increasing Firmicutes, Bacteroidetes, Clostridium and decreasing TM7, thereby maintaining intestinal health.     

短双歧杆菌对Aβ;导致的阿尔兹海默症小鼠肠道菌群及代谢物的影响

为分析2株不同来源的短双歧杆菌对脑部微注射Aβ;蛋白导致的阿尔兹海默症小鼠肠道菌群及其代谢物的影响,给小鼠海马区注射Aβ;蛋白建立阿尔兹海默症小鼠模型,连续灌胃6周2株不同来源的短双歧杆菌,收集小鼠粪便,采用Illumina MiSeq高通量测序技术分析菌群的多样性及物种组成,并采用GC-MS技术检测小鼠粪便中短链脂肪酸的含量。菌群多样性分析发现,Aβ;蛋白注射改变了小鼠的菌群多样性及物种结构,灌胃短双歧杆菌可一定程度上改善菌群紊乱。进一步在属水平和种水平分析各组菌群差异,发现灌胃短双歧杆菌MY显著提高了大鼠肠道中产短链脂肪酸菌Coprococcus spp.、Lactobacillus reuteri和Akkermansia muciniphila的相对丰度,且有效调控了肠道内3种短链脂肪酸的水平。短双歧杆菌MY可能通过调节肠道菌群及其代谢物短链脂肪酸的水平缓解小鼠的认知障碍。     

肠源性短链脂肪酸生成机制及其饮食调控

短链脂肪酸(short chain fatty acids, SCFAs)作为肠道微生物的重要代谢产物,将宿主饮食与肠道微生物之间复杂的相互作用关系有机地联系在一起。SCFAs是近年来微生物代谢产物与人体健康科研领域研究热点,SCFAs不仅作为肠道上皮细胞的重要能源物质,也是游离脂肪酸受体的天然配体,因此发挥着多种健康作用,如调节脂质代谢、免疫、炎症反应和食欲等。阐述了肠源性SCFAs前体物质的主要食物来源,详细探讨了参与SCFAs生成的肠道微生物及代谢途径,并提出了肠源性SCFAs的饮食调控策略。从化学结构上看,SCFAs是一类碳原子数小于7的挥发性有机酸,肠源性SCFAs主要包括乙酸、丙酸、丁酸,它们主要是由SCFAs前体物质在肠道菌群的酵解作用下转化生成。SCFAs前体物质的食物来源多种多样,不易消化的碳水化合物是SCFAs的主要食物前体,包含抗性淀粉、非淀粉多糖、低聚糖等。肠道中的多种微生物能够通过不同代谢途径独立或者协同利用SCFAs前体物质产生SCFAs。补充富含SCFAs前体物质的食物,不仅能够影响肠源性SCFAs的含量,还可选择性地促进肠道中有益菌的生长,从质和量上维护肠道微生态稳态、直接或者间接地调节机体多种生理功能,促进人体健康功能。希望可为预防和治疗相关代谢和免疫疾病提供新的思路。     

5 种食品原料对高脂饮食诱导的肥胖大鼠肠道菌群和短链脂肪酸的影响

香蕉粉、魔芋精粉、抗性糊精、玉米淀粉以及左旋肉碱这5 种食品原料据报道都有减肥功能,但它们对肠道微生物和代谢产物的影响以及与肠道菌群相关的减肥机制的差异尚不清楚。本研究采用16S rRNA测序检测肥胖大鼠肠道内容物,并通过高效液相色谱法（high performance liquid chromatography,HPLC）测定粪便中短链脂肪酸的含量。结果显示：益生菌属Ruminococcus_2、Coprococcus_2和Ruminiclostridium_5分别在玉米淀粉、香蕉粉和抗性糊精组中富集。Spearman相关性分析和典型关联分析（canonical correlation analysis,CCA）结果表明,肠道微生物的变化与糖脂代谢相关的生化参数密切相关。以可溶性膳食纤维为主的原料（魔芋粉和抗性糊精）和以不可溶性膳食纤维（抗性淀粉）为主的原料（香蕉粉和玉米淀粉）对短链脂肪酸的产生能力贡献度相当,均优于左旋肉碱。5 种原料增殖肠道益生菌、抑制有害菌的效果依次为抗性糊精＞香蕉粉＞玉米淀粉＞魔芋精粉,增加短链脂肪酸含量的能力依次为香蕉粉＞抗性糊精＞玉米淀粉＞魔芋精粉,而左旋肉碱对肠道菌群和短链脂肪酸几乎没有什么影响。CCA结果显示,糖脂代谢生化指标与肠道微生物群落的相关程度为空腹血糖水平＞高密度脂蛋白胆固醇水平＞总胆固醇水平＞低密度脂蛋白胆固醇水平＞总甘油三酯水平。Spearman相关性分析表明Ruminococcus_2与丁酸含量呈正相关,Escherichia.Shigella与乙酸、丁酸和总短链脂肪酸含量呈正相关。     

枸杞多糖体外调节人体肠道菌群的功能研究

为研究枸杞多糖(LBP)对人体肠道菌群结构和代谢产物的影响,对6名健康人的粪便提取物进行单独样本与混合样本的体外模拟厌氧发酵,利用16S rRNA基因高通量测序技术对发酵后肠道菌群进行结构和功能分析,并利用超高效液相色谱(UPLC)检测发酵液中的短链脂肪酸(SCFAs)浓度。结果表明,LBP能够明显改变人体肠道菌群结构与功能,提高肠道菌群中益生菌乳酸杆菌属与双歧杆菌属的丰度,并促进了SCFAs的产生。因此,LBP能够显著影响人体肠道菌群结构与功能。     

黑灵芝多糖对糖尿病大鼠血糖血脂调节及肠道菌群的影响

2型糖尿病是一种以高血糖和胰岛素抵抗为特征的代谢性疾病,它的发生、发展与肠道菌群密切相关。本实验旨在研究黑灵芝多糖对2型糖尿病大鼠的保护作用,探讨其对肠道菌群结构和代谢产物的影响。方法：选取Wistar大鼠,给予高糖高脂饲料喂养8?周,采用链脲佐菌素（streptozotocin,STZ）尾静脉注射法建立大鼠糖尿病模型。造模成功后的大鼠分别给予双蒸水、二甲双胍以及高（100?mg/kg?mb）、中（50?mg/kg?mb）、低（25?mg/kg?mb）剂量黑灵芝多糖,连续灌胃4?周后检测生化指标,分析空腹血糖（fasting blood glucose,FBG）、血清总胆固醇（total cholesterol,TC）、甘油三酯（triglyceride,TG）、低密度脂蛋白胆固醇（low-density lipoprotein cholesterol,LDL-C）、高密度脂蛋白胆固醇（high-density lipoprotein cholesterol,HDL-C）、胰岛素（insulin,INS）水平;观察肠道的病理学改变;采集粪便进行16S rDNA高通量测序,分析黑灵芝多糖对糖尿病大鼠肠道菌群的影响;检测粪便中短链脂肪酸（short chain fatty acids,SCFAs）含量。结果：黑灵芝多糖对糖尿病大鼠肠道的组织结构具有一定的保护作用,可以通过调控血糖水平、降低血脂水平和减轻胰岛素抵抗从而起到抗糖尿病作用。此外,黑灵芝多糖能够在一定程度上调节糖尿病大鼠肠道微生物的物种构成,显著增加Cyanobacteria的相对丰度,上调有益菌如Lactobacillus、Roseburia、Bifidobacterium的相对丰度,产酸菌Oscillospira、Ruminococcus、Coprococcus的相对丰度,增加SCFAs中丁酸的分泌;下调Prevotella和CF231的相对丰度,减少丙酸含量。结论：黑灵芝多糖对STZ诱导的糖尿病大鼠血糖血脂和胰岛素具有一定调控作用,其机制可能是通过改变大鼠肠道中微生物的结构组成,进而调节SCFAs的分泌,SCFAs通过被肠道细胞利用和进入血液循环对各个组织起到保护作用。     

海参皂苷对去卵巢小鼠骨密度的改善作用及机制

目的：研究海参皂苷对双侧去卵巢小鼠骨密度的影响及作用机制。方法：雌性健康C57BL/6J小鼠采用去卵巢术建立骨质疏松症模型,术后4 周,随机分为假手术组（生理盐水）、模型组（生理盐水）和低、高剂量海参皂苷组（分别为7.5、15.0 mg/kg mb）。连续灌胃90 d后,检测尿钙浓度、尿磷浓度、骨密度和骨矿化沉积率,评价海参皂苷对模型小鼠骨矿物质的影响;进一步通过测定ALP等成骨标志指标的mRNA表达情况,以及调控其表达水平的Wnt/β-catenin通路关键基因的mRNA表达情况,探究海参皂苷改善骨密度的分子机制。结果：尿液检测显示,海参皂苷能够显著降低尿钙、磷浓度（P＜0.05）,减少骨矿流失;双能X射线扫描及荧光双标记结果显示,海参皂苷能显著增加去卵巢小鼠骨密度,提高骨矿化沉积率（P＜0.05）;实时荧光定量聚合酶链式反应结果表明,海参皂苷显著降低Wnt/β-catenin通路中关键基因的水平（P＜0.05）,下调骨生成标志基因ALP、OCN、Col1a和BMP2的mRNA表达水平（P＜0.05）。结论：海参皂苷能通过抑制Wnt/β-catenin通路降低去卵巢模型小鼠代偿性增加的骨生成,并能够抑制骨矿流失,提高骨密度和骨矿化沉积,改善骨质疏松症。     

Changes in polyphenol fractions and bacterial composition after in vitrofermentation of apple peel polyphenol by gut microbiota

The changes in polyphenol fractions after in vitro fermentation of apple peel polyphenol (APP) by gut microbiota as well as the effects of APP on the growth, pH value, short-chain fatty acids (SCFAs) production and intestinal flora composition of gut microbiota fermentation were firstly explored in this study. The relative abundance of Lactobacillus in the APP group was 49.55% with an increment of 49.40% compared with the blank group, while that of Bifidobacterium was 13.32%. Moreover, the flora produced 37.093 ± 0.478 mM of SCFAs including acetic acid, propionic acid, butyric acid and valeric acid during the process of fermentation, thus reduced the environmental pH value. In addition, polyphenol fractions in APP were altered by gut microbiota fermentation to some extent, for example, glycosides were hydrolysed to aglycones. These findings suggested APP as a potential prebiotic agent to alleviate the disorder of intestinal flora.     

应用Illumina NovaSeq测序技术比较3 种杂粮对大鼠肠道菌群的影响

为探究燕麦、荞麦和小米对健康大鼠肠道结构、肠道菌群及肠道中短链脂肪酸（short-chain fatty acids,SCFAs）含量的影响,本实验将48 只SPF级雄性SD大鼠随机分为4 组（空白对照组（饲喂标准维持饲料）、燕麦组（饲喂含22%（质量分数,下同）燕麦的饲料）、荞麦组（饲喂含22%荞麦的饲料）和小米组（饲喂含22%小米的饲料））,每周测定大鼠体质量,12 周后处死大鼠,取肝脏、结肠组织及结肠内容物,对大鼠肝脏和结肠组织进行病理学检测;应用Illumina NovaSeq高通量测序技术检测大鼠肠道菌群变化;利用液相色谱-质谱联用仪检测大鼠结肠内容物SCFAs含量。结果表明,燕麦可增加大鼠肠道菌群多样性,提高大鼠结肠乳杆菌属（Lactobacillus）和阿克曼氏菌属（Akkermansia）丰度;荞麦和小米可增加厚壁菌门（Firmicutes）相对丰度,降低疣微菌门（Verrucomicrobia）和拟杆菌门（Bacteroidetes）相对丰度;燕麦、荞麦和小米均可降低拟杆菌属（Bacteroides）丰度;燕麦和小米可显著提高大鼠结肠内乙酸和总SCFAs含量（P＜0.05）,小米可显著提高丙酸和异丁酸含量（P＜0.05）。综上,燕麦对大鼠肠道菌群具有一定的改善作用,荞麦和小米对肠道菌群的影响相似度较高,相关研究结果可为谷物功能食品的开发提供科学依据。     

Olive-Derived Antioxidant Dietary Fiber Modulates Gut Microbiota Composition and Attenuates Atopic Dermatitis Like Inflammation in Mice

Scope

Epidemiological data suggest that altered gut microbiota contributes to the development of atopic dermatitis (AD). The effect of an olive-derived antioxidant dietary fiber (OADF) in relieving AD symptoms in a murine model of 2,4-dinitrofluorobenzene (DNFB)-induced AD is examined and the effect of OADF in modulating host gut microbiota is explored.

Methods and results

Mice are fed with either standard diet or standard diet + OADF for 3 weeks prior to induction of AD and maintained on the same diet throughout the DNFB application period. Dietary OADF causes significant improvement of AD-like symptoms with reduced serum levels of immunoglobulin (Ig)E, interleukin (IL)-1β, IL-6, C-X-C motif ligand (CXCL)1, and increased serum levels of IL-10. OADF supplementation restore gut microbiota composition that are altered in AD mice. Specifically, OADF increases the proportion of intestinal bacteria (Ruminococcaceae UCG014, GCA900066575, UBA1819) associated with enhanced butyrate production, along with inhibiting Clostridiales vadin BB60 which are more prevalent in AD mice.

Conclusion

OADF modulates gut microbiota composition, improves cytokine profile and butyrate production influencing AD-associated immune response. Results highlight the importance of the gut-skin axis for the AD dietary therapeutic agents.     

Effects of deep frying vegetable oils rich in PUFAs on gut microbiota in rats

Vegetable oils rich in PUFAs are widely used in daily cooking and food industry, and PUFAs could be utilised by gut microbiota and present prebiotic effects. However, PUFAs are unstable in high-temperature cooking like frying. In the current study, we aimed to explore the influence of thermally oxidised oils rich in PUFA on gut microbiota. Two vegetable oils: omega-3 alpha-linolenic acid (ALA)-rich perilla oil or omega-6 linoleic acid-rich sunflower oil were heated at 180 °C for 10 h, and then fed to male SD rats for 14 weeks. Administration of heated perilla oil dramatically increased the relative abundance of Akkermansia muciniphila, a recent identified probiotics which may weaken intestinal mucus barrier, and inhibited the expression of several tight junction-related genes including occludin and claudin-1 in colon. Consumption of thermally oxidised sunflower oil stimulated the proliferation of Bifidobacterium. Our findings suggested that thermally processing has complicated effects on the prebiotic effects of vegetable oils rich in PUFAs, and perilla oil fried foods may be potential sources to stimulate Akkermansia proliferation in gut.     

Fabrication of quercetin-loaded nanoparticles based on Hohenbuehelia serotina polysaccharides and their modulatory effects on intestinal function and gut microbiota in vivo

This research was aimed to construct the nanoparticles based on Hohenbuehelia serotina polysaccharides for encapsulation of quercetin (QC-HSP NPs), and investigate their effects on intestinal function and gut microbiota in mice. Results showed that in comparison with HSP and control, QC-HSP NPs significantly improved immune organ indexes, colon length, fecal moisture content and intestinal peristalsis capacity of mice. The productions of short-chain fatty acids (SCFAs) in colon were also increased after treatment with QC-HSP NPs, while the colonic fecal pH was decreased and defecation time was shortened. Through analysis of 16S rRNA sequencing, QC-HSP NPs could increase α and β diversities of gut microbiota, modulate their structure and composition, and increase the relative abundance of beneficial bacteria together with reducing the richness of harmful bacteria. In addition, QC-HSP NPs ameliorated the metabolic functions of gut microbiota by modulating metabolic pathways. This study suggested that QC-HSP NPs might be served as a prebiotic for protecting intestinal health.     

动物双歧杆菌乳亚种XLTG11对克林霉素诱导的抗生素相关性腹泻的改善作用

目的：通过克林霉素诱导抗生素相关性腹泻(antibiotic-associated diarrhea,AAD)模型,探究动物双歧杆菌乳亚种XLTG11缓解小鼠AAD的作用。方法：将48只6周龄C57BL/6N雄鼠随机分为4组：对照组、模型组、低剂量组和高剂量组,除对照组外,各组小鼠连续14 d灌胃克林霉素(250 mg/(kg m_b·d))诱导AAD模型,然后低剂量组和高剂量组灌胃不同剂量(0.2 mL,5×10⁶、1×10⁷ CFU)动物双歧杆菌乳亚种XLTG11,测定小鼠体质量增长量、盲肠质量、粪便含水量和粪便稠度,测定结肠肿瘤坏死因子α、白细胞介素6(interleukin 6,IL-6)、IL-1β、IL-10水平,血清脂多糖(lipopolysaccharide,LPS)和D-乳酸质量浓度,测定肠道菌群组成及短链脂肪酸含量,以及肠道屏障和核因子κB(nuclear factor kappa-B,NF-κB)信号通路相关基因表达水平。结果：高剂量动物双歧杆菌乳亚种XLTG11显著提高AAD模型小鼠的体质量增长量和...     

Dietary Polyphenols and Human Gut Microbiota: a Review

Dietary polyphenols are substrates for colonic microbiota. They and their metabolites contribute to the maintenance of gastrointestinal health by interacting with epithelial cells, and largely by modulating the gut microbial composition. Polyphenols may act as promoting factors of growth, proliferation, or survival for beneficial gut bacteria—mainly Lactobacillus strains—and thus, exerting prebiotic actions and inhibiting the proliferation of some pathogenic bacteria such as Salmonella and Helicobacter pylori species. To date the interactions affecting metabolic pathways and numerous metabolites of dietary polyphenols have been widely documented. However, the effects of dietary polyphenols on the modulation of the intestinal ecology and on the growth of gut microbial species are still poorly understood. This paper summarizes data on the influence of dietary polyphenols on gut microbiota and the main interactions between dietary polyphenols and beneficial and pathogenic intestinal bacteria.     

植物多酚通过Wnt/β-catenin信号通路抗肿瘤作用研究进展

Wnt信号传导通路是传递生长、发育信息的重要通路,与胚胎发育,细胞存活、生长、增殖、分化关系密切。此条通路的激活或抑制对肿瘤的发生发展有重要作用。植物多酚因其抗肿瘤潜能而成为开发防癌物质的重要来源。本文通过介绍Wnt/β-catenin信号通路的组成、调节机制及其与肿瘤的关系,总结植物多酚对肿瘤细胞中Wnt信号通路的作用机制,明确植物多酚对Wnt通路的有效靶点,为植物多酚保健食品(或药物)的开发提供新的依据。     

副干酪乳杆菌LPC-F通过促进Cajal间质细胞增殖缓解便秘

便秘(constipation)是一类常见的胃肠道疾病,其发病率呈逐年上升的趋势。临床研究发现,便秘患者肠道菌群失调。通过赋予机体一定量的活性益生菌来调节肠道菌群,已然成为治疗便秘的重要手段。因此,该研究选取2株具有不同缓解便秘效果的副干酪乳杆菌进行研究。通过对便秘相关指标的检测,再次证实仅有来源于健康成人粪便中的副干酪乳杆菌LPC-F具有缓解便秘的作用。进一步通过对便秘相关胃肠调节肽、血清中炎症因子、结肠Cajal间质细胞的数量、肠道菌群及其代谢产物短链脂肪酸等指标进行检测,解析副干酪乳杆菌LPC-F缓解便秘的可能方式。结果表明副干酪乳杆菌LPC-F可能通过改变肠道菌群的结构,提高肠道内乙酸的水平,乙酸则通过刺激肠嗜铬细胞释放5-羟色胺(5-hydroxytryptamine, 5-HT),释放入肠腔的5-HT通过与其受体相结合,促进结肠Cajal间质细胞(interstitial cells of Cajal, ICC)的增殖,从而最终增强肠蠕动缓解便秘。