Evaluation and comparison of short chain fatty acids composition in gut diseases

BACKGROUND An altered (dysbiosis) and unhealthy status of the gut microbiota is usually responsible for a reduction of short chain fatty acids (SCFAs) concentration. SCFAs obtained from the carbohydrate fermentation processes are crucial in maintaining gut homeostasis and their determination in stool samples could provide a faster, reliable and cheaper method to highlight the presence of an intestinal dysbiosis and a biomarker for various gut diseases. We hypothesize that different intestinal diseases, such as celiac disease (CD), adenomatous polyposis (AP) and colorectal cancer (CRC) could display a particular fecal SCFAs’ signature. AIM To compare the fecal SCFAs’ profiles of CD, AP, CRC patients and healthy controls, using the same analytical method. METHODS In this cross-sectional study, we defined and compared the SCFAs’ concentration in fecal samples of 9 AP, 16 CD, 19 CRC patients and 16 healthy controls (HC). The SCFAs’ analysis were performed using a gas-chromatography coupled with mass spectrometry method. Data analysis was carried out using Wilcoxon ranksum test to assess pairwise differences of SCFAs’ profiles, partial least squaresdiscriminate analysis (PLS-DA) to determine the status membership based on distinct SCFAs’ profiles, and Dirichlet regression to determine factors influencing concentration levels of SCFAs. RESULTS We have not observed any difference in the SCFAs’ amount and composition between CD and healthy control. On the contrary, the total amount of SCFAs was significantly lower in CRC patients compared to HC (P = 0.044) and CD (P = 0.005). Moreover, the SCFAs’ percentage composition was different in CRC and AP compared to HC. In detail, HC displayed higher percentage of acetic acid (P value = 1.3 × 10-6) and a lower amount of butyric (P value = 0.02192), isobutyric (P value = 7.4 × 10-5), isovaleric (P value = 0.00012) and valeric (P value = 0.00014) acids compared to CRC patients. AP showed a lower abundance of acetic acid (P value = 0.00062) and higher percentages of propionic (P value = 0.00433) and isovaleric (P value = 0.00433) acids compared to HC. Moreover, AP showed higher levels of propionic acid (P value = 0.03251) and a lower level of isobutyric acid (P value = 0.00427) in comparison to CRC. The PLS-DA model demonstrated a significant separation of CRC and AP groups from HC, although some degree of overlap was observed between CRC and AP. CONCLUSION Analysis of fecal SCFAs shows the potential to provide a non-invasive means of diagnosis to detect patients with CRC and AP, while CD patients cannot be discriminated from healthy subjects.

Fecal microbes, short chain fatty acids, and colorectal cancer across racial/ethnic groups

AIM:To investigate differences in microbes and short chain fatty acid(SCFA) levels in stool samples from Hispanic and non-Hispanic African American,American Indian,and White participants.METHODS:Stool samples from twenty participants were subjected to analysis for relative levels of viable bacteria and for SCFA levels.Additionally,the samples were subjected to 16 S r RNA gene pyrosequencing for identification of bacteria present in the stool.We used a metagenome functional prediction technique to analyze genome copy numbers and estimate the abundance of butyrate kinase in all samples.RESULTS:We found that African Americans had significantly lower levels of acetate,butyrate,and total SCFAs than all other racial/ethnic groups.We also found that participant microbial profiles differed by racial/ethnic group.African Americans had significantly more Firmicutes than Whites,with enriched Ruminococcaceae.The Firmicutes /Bacteroidetes ratio was also significantly higher for African Americans than for Whites(P =0.049).We found Clostridium levels to be significantly and inversely related to total SCFA levels(P =0.019) and we found Bacteroides to be positively associated(P =0.027) and Clostridium to be negatively associated(P =0.012) with levels of butyrate.We also identified a correlation between copy number for a butyrate kinase predicted from 16 S r RNA gene abundance and levels of butyrate in stool.CONCLUSION:The identified differences in gut flora and SCFA levels may relate to colorectal cancer mortality differentials and may be useful as targets for future clinical and behavioral interventions.

Kinetic analysis of waste activated sludge hydrolysis and short-chain fatty acids production at pH 10

The accumulation of short-chain fatty acids （SCFAs）, a preferred carbon source for enhanced biological phosphorus removal microbes, was significantly improved when waste activated sludge （WAS） was fermented at pH 10. The kinetics of WAS hydrolysis and SCFAs production at pH 10 was investigated. It was observed that during WAS anaerobic fermentation the accumulation of SCFAs was limited by the hydrolysis process, and both the hydrolysis of WAS particulate COD and the accumulation of SCFAs followed first-order kinetics. The hydrolysis and SCFAs accumulation rate constants increased with increasing temperature from 10 to 35℃, which could be described by the Arrhenius equation. The kinetic data further indicated that SCFAs production at pH 10 was a biological process. Compared with the experiment of pH uncontrolled （blank test）, both the rate constants of WAS hydrolysis and SCFAs accumulation at 20℃ were improved significantly when WAS was fermented at pH 10.

Effects of <i>γ</i>-Polyglutamic Acid on Blood Glucose and Caecal Short Chain Fatty Acids in Adult Male Mice

γ-Polyglutamic acid (γ-PGA) is a major component of Natto. We hypothesized that γ-PGA could reduce postprandial glucose rise and plasma glucose levels. Mice were fed a 0.1% γ-PGA—containing diet or control diet for 91 days. Maltose and starch tolerance tests were performed, and plasma lipids, glucose levels, and caecal short chain fatty acids (SCFAs) were measured. Mice were co-administered γ-PGA and starch to suppress the initial rise in blood glucose levels. Blood glucose levels at 15 min were significantly lower in the PGA group than in the Con group (P 0.05). The plasma glucose level and NEFA level were also significantly lower in the PGA group (P 0.05), and caecal acetic acid/total caecal SCFAs ratio was significantly increased in the PGA group (P 0.05). Significant negative correlations existed between the caecal acetic acid/propionic acid ratio and the weight of visceral fat/BW (r =?-0.57, P = 0.0318). Our results suggest that γ-PGA may effectively prevent metabolic syndrome by lowering blood glucose levels.

Short-Chain Fatty Acids-A Healthy Bus between Gut Microbiota and Organs beyond the Gut

The impact of the gut microbiota is not limited to the intestine, but its interaction with the host produces active metabolites, which can be transported by the blood circulation to play important roles in various parts of the body. Among them, short-chain fatty acids (SCFAs), as important active products of gut bacteria, have been shown to exert anti-inflammatory and immunomodulatory effects and can play active roles as signaling molecules in the development of various intestinal and extraintestinal diseases, such as inflammatory bowel disease, colon cancer, multiple sclerosis, hypertension, allergic airway disease, obesity, diabetes, kidney disease, rheumatoid arthritis, etc. In this way, modulation of the intestinal microbiota and metabolism-active substances has gradually become a popular therapeutic method for many diseases of organs beyond the gut. To find new therapeutic targets for major human health problems, this article reviews the research on SCFAs in extraintestinal diseases.

Double-side role of short chain fatty acids on host health via the gut-organ axes

Short chain fatty acids(SCFA)exist in dietary foods and are produced by the fermentation of gut microbiota,and are considered an important element for regulating host health.Through blood circulation,SCFA produced in the gut and obtained from foods have an impact on the intestinal health as well as vital organs of the host.It has been recognized that the gut is the“vital organ”in the host.As the gut microbial metabolites,SCFA could create an“axis”connecting the gut and to other organs.Therefore,the“gut-organ axes”have become a focus of research in recent years to analyze organism health.In this review,we summarized the sources,absorption properties,and the function of SCFA in both gut and other peripheral tissues(brain,kidney,liver,lung,bone and cardiovascular)in the way of“gut-organ axes”.Short chain fatty acids exert both beneficial and pathological role in gut and other organs in various ways,in which the beneficial effects are more pronounced.In addition,the beneficial effects are reflected in both preventive and therapeutic effects.More importantly,the mechanisms behinds the gut and other tissues provided insight into the function of SCFA,assisting in the development of novel preventive and therapeutic strategies for maintaining the host health.

基于肠道菌群及其代谢产物SCFA探讨左归降糖通脉方对2型糖尿病大鼠糖脂代谢的影响

目的基于肠道菌群及代谢产物短链脂肪酸(short-chain fatty acid,SCFA)探讨左归降糖通脉方(Zuogui Jiangtang Tongmai formula,ZJTF)干预2型糖尿病(type 2 diabetes mellitus,T2DM)的可能机制。方法取12只SD大鼠为空白(Control)组,喂食普通饲料;48只大鼠为造模组,以高脂饲料联合链脲佐菌素(streptozocin,STZ)制备T2DM模型。造模成功后随机分为模型(DM)组、ZJTF低剂量(ZJTF.L,12 g·kg^(-1))组、ZJTF高剂量(ZJTF.H,24 g·kg^(-1))组、二甲双胍150 mg·kg^(-1)+阿托伐他汀10 mg·kg^(-1)(M.A)组,药物干预4周。监测大鼠精神状态、体质量与随机血糖;ELISA检测血清胰岛素(insulin,INS)、糖化血红蛋白(glycosylated hemoglobin,HbA1c)、炎症因子的水平;生化分析法检测血脂常规含量;HE染色观察结肠病理改变;16SrRNA观察肠道菌群结构;GC-MS检测血清SCFA水平。结果与Control组比较,DM组出现多饮、多食、多尿、体质量减轻等症状;血糖、INS、HbA1c明显上升(P<0.01);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)水平升高,高密度脂蛋白胆固醇(high density lipoprotein cholesterol,HDL-C)明显降低(P<0.01);白细胞介素-1β(interleukin-1β,IL-1β)、白细胞介素-6(interleukin-6,IL-6)及肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)水平均明显升高(P<0.01);结肠固有层出现部分中断和消失,细胞肿胀、绒毛紊乱。DM组厚壁菌门和变形菌门、肠杆菌科、埃希菌-志贺菌属的相对丰度增加;血清乙酸、丁酸含量下降(P<0.05,P<0.01)。与DM组比较,ZJTF组血糖、INS、HbAlc均明显降低(P<0.05,P<0.01);TC、TG、LDL-C明显降低,HDL-C明显升高(P<0.01);IL-1β、IL-6及TNF-α水平明显降低(P<0.01);结肠细胞肿胀及炎性浸润缓解;拟杆菌门和疣微菌门、乳酸菌科、阿克曼菌属丰度增加;血清丁酸、乙酸含量升高(P<0.05,P<0.01)。结论左归降糖通脉方可能通过调节肠道菌群和SCFAs水平起到降血糖、稳血脂、减轻炎症反应的作用。

Processing Effect on the Physicochemical and Volatile Fatty Acid Profile of African Breadfruit (Treculia africana) Seed Oil

African breadfruit seeds were subjected to three processing methods—parboiling, cooking and toasting, and the raw was used as control. The purpose of this research was to extract the oil from the seed and to determine the effect of processing on the oil for physicochemical properties and volatile fatty acid profile. Physicochemical properties showed that the colour of the oil varied from golden yellow to brownish yellow with specific gravity varying between 0.802 g/cm3 and 0.813 g/cm3. Percentage yield of oil was 6.14% for raw extract, 6.62% for parboiled extract, 7.56% for toasted extract, and 5.01% for cooked extract. Acid, peroxide and saponification value for oil extracted from the raw seed varied with the processed samples value. The Volatile Fatty Acid (VFA), also known as Short Chain Fatty Acid (SCFA) found inherent in varying concentration, were formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, isocarproic, hexanoic and heptanoic acid. Overall results prove that heat results in increases in the VFA concentration of the processed oil.

Multi-Compartment SCFA Quantification in Human

Short-chain fatty acids (SCFA) play an important role in human biochemistry. They originate primarily from the digestive system through carbohydrates microbial fermentation. Most SCFA produced in the colon are absorbed by the intestinal wall and enter the bloodstream to be distributed throughout the body for multiple purposes. At the intestinal level, SCFA play a role in controlling fat storage and fatty acid metabolism. The effects of these beneficial compounds therefore concern overall health. They facilitate energy expenditure and are valuable allies in the fight against obesity and diabetes. SCFA are also involved in the regulation of the levels of several neurotransmitters such as GABA (γ-aminobutyric acid), glutamate, serotonin, dopamine, and norepinephrine. Their role is also highlighted in many inflammatory and neurodegenerative diseases such as Alzheimer’s disease (AD) or Parkinson’s disease (PD). To have a realistic picture of the distribution of SCFA in different biological compartments of the human body, we propose to study SCFA simultaneously in five human biological samples: feces, saliva, serum, cerebrospinal fluid (CSF), and urine, as well as in Dried Blood Spot (DBS). To evaluate their concentration and repeatability, we used 10 aliquots from pooled samples, analyzed by 3-nitrophenylhydrazine (3-NPH) derivation and liquid chromatography coupled with high sensitivity mass spectrometry (LC-QqQ-MS). We also evaluated the SCFA assay on Dried Blood Spot (DBS). In this work, we adapted the pre-analytical parts for each sample to be able to use a common calibration curve, thus facilitating multi-assay quantification studies and so being less time-consuming. Moreover, we proposed new daughter ions from the same neutral loss (43 Da) to quantify SCFAs, thus improving the sensitivity. In conclusion, our methodology, based on a unique calibration curve for all samples for each SCFA, is well-suited to quantified them in a clinical context.

The interaction among gut microbes,the intestinal barrier and short chain fatty acids

The mammalian gut is inhabited by a massive and complicated microbial community, in which the hostachieves a stable symbiotic environment through the interdependence, coordination, reciprocal constraintsand participation in an immune response. The interaction between the host gut and themicrobiota is essential for maintaining and achieving the homeostasis of the organism. Consequently, guthomeostasis is pivotal in safeguarding the growth and development and potential productive performanceof the host. As metabolites of microorganisms, short chain fatty acids are not only the preferredenergy metabolic feedstock for host intestinal epithelial cells, but also exert vital effects on antioxidantsand the regulation of intestinal community homeostasis. Herein, we summarize the effects of intestinalmicroorganisms on the host gut and the mechanisms of action of short chain fatty acids on the fourintestinal barriers of the organism, which will shed light on the manipulation of the intestinal communityto achieve precise nutrition for specific individuals and provide a novel perspective for theprevention and treatment of diseases.

Gut microbiota-derived short chain fatty acids are potential mediators in gut inflammation

Gut inflammation is a challenging concern in humans and animals,which disturbs normal growth and leads to severe bowel diseases.Short chain fatty acids(SCFA)are the gut microbiota metabolites produced from fermentation of non-digestible carbohydrates,and have been reported to modulate gut inflammation.SCFA have been implicated as the potential therapeutic bioactive molecules for gut inflammatory diseases,and could be an alternative to antibiotic growth promoters(AGP).In this review,the existing knowledge about the types of SCFA,the related gut microbes producing SCFA,the roles of SCFA in maintaining gut homeostasis,and how SCFA modulate gut inflammation is summarized.The therapeutic application of SCFA in the treatment of inflammatory bowel disease(IBD)is also highlighted

Infusion of short chain fatty acids in the ileum improves the carcass traits,meat quality and lipid metabolism of growing pigs

Short chain fatty acids(SCFA)are the main products of indigestible carbohydrates undergoing bacterial fermentation in the hindgut,which are related to some physiological functions.This study was designed to investigate the effects of SCFA infusion by ileum on the carcass traits,meat quality and lipid meta-bolism of growing pigs.In a 28-day study,24 growing barrows fitted with a T-cannula in distal ileum were divided into 4 treatments:1)Control,2)antibiotics(AB),3)AB+300 mL of SCFA1 solution(ABS1),4)AB+300 mL of SCFA2 solution(ABS2).The concentrations of acetate,propionate and butyrate in SCFA1 solution were respectively 61.84,18.62 and 12.55 mmol/L,and in SCFA2 were respectively 40.08,15.41 and 9.78 mmol/L The results showed that the SCFA infusion increased the average daily feed intake and average daily gain of pigs(P<0.05).Meanwhile,the SCFA treatments increased longissimus dorsi area(P<0.05)and carcass weight(P=0.058),decreased the drip loss of longissimus dorsi(P=0.059),and reduced serum concentrations of triglyceride,total cholesterol and urea nitrogen(P<0.05).Besides,the SCFA administration inhibited the mRNA expressions of fatty acid synthase(FAS)and acetyl-CoA carboxylase in longissimus dorsi(P<0.05),the mRNA expression of FAS in the liver(P<0.05),and the mRNA expression of hormone-sensitive lipase in abdominal fat(P<0.05).Short chain fatty acid infusion also enhanced the mRNA expression of carnitine palmitoyltransferase-1αin the liver(P<0.05),the mRNA expressions of peroxisome proliferator activated receptor gamma and lipoprotein lipase in abdominal fat(P<0.05),and the mRNA expressions of free fatty acid receptor 2,glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon(P<0.05).These results suggested that SCFA administration in the ileum could improve the carcass traits and meat quality of growing pigs,which was possibly due to the fact that SCFA modulated lipid metabolism.

Production of short chain fatty acids and vitamin B_(12) during the in-vitro digestion and fermentation of probiotic chocolate

The prebiotic functions of chocolate to improve the function and health benefit of the chocolate when enriched with probiotics has not been fully investigated.This study investigated the role of chocolates enriched with probiotics in the production of SCFAs and vitamin B_(12) during the in-vitro colonic fermentation.Seven probiotic bacteria were encapsulated using a mixture of cocoa powder(10%),FOS(2%)and Na-alginate(1%)before added to chocolates.The results revealed that encapsulated Lactobacillus plantarum and Bifidobacterium animalis spp.lactis BB12 produced significantly higher amounts(1876.5±105.16 and 1348.51±77.37 mmol,respectively)of acetic acid after 48h of colonic fermentation.Chocolates with encapsulated BB12,La5,Lactobacillus sanfranciscensis and Streptococcus thermophilus yielded higher amounts of propionic,isobutyric,butyric and isovaleric acid.Probiotic-chocolates with 70%cocoa produced significantly more acetic,propionic,and butyric acids than that of 45%cocoa.However,Probiotic-chocolates with 45%cocoa produced greater amounts of vitamin B_(12) than 70%cocoa.These data demonstrate that probiotic-chocolate could be a functional snack with additional health benefits.

A new process to improve short-chain fatty acids and bio-methane generation from waste activated sludge

As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.

“原络通经”针法调节痴呆小鼠肠道菌群微生态及肠道SCFA代谢的机制研究

目的探讨“原络通经”针法调节痴呆小鼠肠道菌群多样性及肠道SCFA代谢的机制研究。方法SAMP8小鼠随机分成3组:模型对照组、原络通经组、百会针刺组,每组6只;以SAMR1同品系正常小鼠6只作为空白对照组,通过Morris水迷宫检测治疗后小鼠空间学习记忆能力的变化,免疫组织化学分析β淀粉样蛋白1-42(Aβ_(1-42))表达水平,qRT-PCR和Western blot检测Aβ_(1-42)和淀粉样蛋白前体蛋白(APP)表达情况,16S rRAN测序检测肠道菌群多样性,采用气相色谱质谱联用方法分析肠道短链脂肪酸(SCFA)。结果与空白对照组相比,模型对照组小鼠逃避潜伏时间显著增加,原络通经组和百会针刺组逃避潜伏时间显著减少,且原络通经组改善更显著(P<0.05);与空白对照组相比,模型对照组脑组织Aβ_(1-42)和APP基因表达显著增加,原络通经组和百会针刺组基因表达显著减少,且原络通经组改善更显著(P<0.05);与空白对照组相比,模型对照组肠道菌群多样性和肠道短链脂肪酸含量显著降低,原络通经组和百会针刺组肠道菌群多样性和肠道短链脂肪酸含量显著增高,且原络通经组改善更显著(P<0.05)。结论原络通经疗法与百会针刺均可改善痴呆小鼠学习记忆功能障碍,降低脑组织Aβ_(1-42)和APP基因表达,改善肠道菌群多样性及增加肠道短链脂肪酸含量,而原络通经疗法疗效更优。

盲肠灌注不同SCFA对驴乳生产性能及乳脂肪酸组成的影响

旨在了解驴盲肠发酵产物对乳成分合成的影响。本研究选择4头安装永久盲肠瘘管的泌乳母驴(体重(182±9)kg),在泌乳晚期((155±15)d),经盲肠用连续灌注法,采用4×4拉丁方设计,连续3h灌注3种不同比例和组合的短链脂肪酸(SCFA):乙丙组(乙酸150mmol·h^(-1)+丙酸50mmol·h^(-1))、乙丁组(乙酸170mmol·h^(-1)+丁酸30mmol·h^(-1))、乙丙丁组(乙酸130mmol·h^(-1)+丙酸50mmol·h^(-1)+丁酸20mmol·h^(-1)),对照组灌注相同体积的缓冲液。结果发现,不同处理组间乳产量无显著差异(P>0.10)。乙丁组乳脂、非脂固形物、乳糖和乳蛋白含量均显著高于乙丙丁组(P<0.10);乙丙和乙丁组中乳蛋白含量显著高于乙丙丁组(P<0.10),其余各指标差异不显著(P>0.10)。乙丙和乙丙丁组的中链脂肪酸比例显著高于对照组(P<0.05),乙丙、乙丁和乙丙丁组长链脂肪酸比例显著低于对照组(P<0.05)。结果显示,经盲肠灌注乙酸和丁酸有助于提高乳成分含量,灌注乙酸和丙酸有利于增加乳脂的中链脂肪酸比例,盲肠SCFA参与并影响驴乳脂合成。

剩余污泥转化为SCFAs及用于增强生物除磷的研究进展

发酵城市污水处理厂的剩余污泥可产生易于生物利用的短链脂肪酸(SCFAs),针对某些城市污水处理厂进水中所含溶解性有机物不能满足生物法需求的情况,可采用投加污泥发酵液作为外碳源来解决。SCFAs是增强生物除磷(EBPR)中聚磷菌厌氧合成聚羟基烷酸(PHAs)的重要基质,其浓度与类型对除磷效果有重要影响。本文就剩余污泥发酵产酸、SCFAs对EBPR的影响及剩余污泥发酵液用于EBPR的研究进行了综述。

肠道菌群-SCFAs在代谢性疾病中的作用研究

肠道菌群被认为是人类体内不可或缺的"器官",其代谢产物如短链脂肪酸(short-chain fatty acids,SCFAs)也被证实生物学作用显著,尤其在机体代谢方面。本文就肠道菌群-SCFAs与代谢性疾病研究进展作一阐述。

基于肠-脑轴探讨针康法调控SCFAs改善缺血性脑卒中预后的新思路

缺血性脑卒中是由于各种原因导致脑动脉血流中断,局部脑组织缺血、缺氧进而坏死,最终出现相应神经功能缺损的脑血管疾病。炎症在脑卒中的病程进展中发挥着重要作用。缺血性脑卒中的炎性反应是一个动态过程,缺血发生后短时间内即发生炎症反应,进而影响中枢神经系统。炎症反应具有级联放大效应,炎症因子会使继发性脑损伤加重,从而影响中枢神经系统的自我修复,炎症标志物水平升高导致患者预后差,产生多种并发症。在针灸镇痛机制的相关研究中,针刺抗炎作用是不容忽视的一个重要方面,主要通过下丘脑-垂体-肾上腺轴(HPA)和自身调节来实现。研究发现针灸刺激不同穴位可激活各自的神经通路,再由神经-内分泌网络发挥效应,如针康法可以通过炎症通路纠正辅助性T细胞/调节性T细胞失衡,并通过维甲酸相关孤儿受体激活编码部分白细胞介素,有效发挥抗炎作用。近年来国内外研究团队发现肠道菌群与脑血管疾病存在紧密联系,其可通过代谢产物或免疫机制影响缺血性脑卒中的发病和预后。胃肠道与大脑具有双向调节作用,抽象概括为肠-脑轴,二者通过多种途径交流联系,如炎症介质、自主神经、内分泌系统以及肠道菌群代谢产物等。短链脂肪酸(SCFAs)是结肠中膳食纤维经细菌发酵的一类代谢物,在维持肠道弱酸性环境和抗炎方面具有关键性作用,能通过多种途径调控大脑功能。急性缺血性脑卒中患者的SCFAs水平降低,卒中后功能障碍的风险也会大大提高。研究发现,针刺可改善脑卒中后患者便秘症状及粪便性状,使肠道菌群中丁酸及总短链脂肪酸浓度升高,α多样性指数升高。适宜浓度的混合SCFAs可通过调控相应炎症通路抑制LPS诱导的小胶质细胞炎症反应,而起到抗炎的保护作用。于临床实验中发现针康法治疗可显著恢复脑卒中患者的运动功能,发挥拮抗脑缺血后炎性反应的作用,主要表现为提高肠内有益菌如乳酸杆菌和双歧杆菌含量,降低部分机会致病菌如梭状芽孢杆菌含量,优化肠道菌群结构,减少参与中枢神经系统和自身免疫性疾病的关键炎症因子和肿瘤坏死因子的表达。综上,从肠脑相通的角度看,针康法调节患者肠道功能从而改善卒中后遗症的机制很有可能与机体SCFAs的代谢有关。

心力衰竭患者血清SCFA、TMAO表达与肠道菌群及代谢综合征的相关性研究

目的探讨心力衰竭患者血清短链脂肪酸(SCFA)、氧化三甲胺(TMAO)表达与肠道菌群及代谢综合征(MS)的相关性。方法选取2020年1月至2020年10月在本院就诊的100例心力衰竭患者作为观察组,另外选取100例同期健康体检者作为对照组。比较两组收缩压、舒张压、空腹血糖(FBG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、总胆固醇(TC)、三酰甘油(TG)、肠道菌群以及血清SCFA、TMAO表达水平差异;采用Spearman分析观察组血清SCFA、TMAO表达水平与代谢相关参数、肠道菌群指标相关性。结果与对照组相比,观察组舒张压、HDL-C、TC及变形菌门、放线菌门、梭杆菌门丰度差异均无统计学意义(P>0.05),收缩压、FBG、LDL-C、TG、厚壁菌门丰度及TMAO表达水平均较高(P<0.05),拟杆菌门丰度及血清乙酸、丙酸、丁酸表达水平较低(P<0.05)。Spearman分析结果显示,观察组血清乙酸、丙酸、丁酸表达水平与收缩压、TG、LDL-C、FBG、厚壁菌门均呈负相关(P<0.05),与拟杆菌门呈正相关(P<0.05);TMAO与收缩压、TG、LDL-C、FBG、厚壁菌门均呈正相关(P<0.05),与拟杆菌门呈负相关(P<0.05)。结论心力衰竭患者血清乙酸、丙酸、丁酸为低表达,TMAO为高表达,均与肠道菌群及MS存在一定相关性,调控机体肠道菌群代谢产物SCFA、TMAO可能成为治疗心力衰竭的新思路。