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超重和肥胖日益成为世界范围内影响人类健康的不良趋势,而这种现象出现的根本原因是现代生活方式所带来的高热量饮食和低能量消耗,而身体仍然按照几十万年前的方式,把多余的热量以脂肪的形式储存起来。近年来的科学研究发现,肠道细菌可以帮助动物转化和吸收食物中的能量,影响动物体内的脂肪含量和体重,而不同门类的肠道细菌在这方面的效果不同。不同的人群中肠道细菌的构成有显著差异,是影响这些人群体重指标的一个因素。 相似文献
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高胆固醇是诱发心脑血管疾病的重要因素之一。目前国内外降低胆固醇的主要方式是药物治疗,但其存在费用高及副作用多的弊端。研究表明,肠道细菌对机体的胆固醇代谢有重要影响,但降胆固醇肠道细菌的筛选方式及功能评价却少有报道。本研究通过培养组学方法,使用牛胆汁酸或人工混合胆汁酸作为筛选条件,从健康人体肠道筛选出36种耐胆汁酸细菌。以鼠李糖乳杆菌GG株 (Lactobacillus rhamnosus GG,LGG) 作为阳性对照,设置0 g/L、0.3 g/L、3 g/L三种胆汁酸浓度组,对耐胆汁酸细菌进行体外降胆固醇能力评估,确定奇异变形菌、斯氏普罗威登斯菌、普通变形菌等10种细菌为降胆固醇优势菌。随后对其中6种降胆固醇优势菌——奇异变形菌、斯氏普罗威登斯菌、普通变形菌、潘氏变形菌、污蝇解克杆菌、雷氏普罗威登斯菌进行体外降甘油三酯能力评估以及人工胃液耐受能力评估。结果显示,上述6株细菌体外降甘油三酯能力均优于LGG。伴随人工胃液pH值的下降和作用时间的延长,6株细菌的生存率均下降。上述筛选实验及功能评价为进一步开发潜在的降胆固醇细菌制品提供研究基础。 相似文献
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胆汁酸作为一种信号分子通过激活肝、肠道和外周组织中的胆汁酸受体影响体内葡萄糖和脂质的代谢平衡,对于调节肥胖、2型糖尿病和非酒精性脂肪肝等代谢性疾病具有非常重要的意义。胆汁酸与相应核受体,如法尼醇X受体(farnesoid X receptor, FXR)和Takeda G蛋白偶联受体5 (Takeda G protein-coupled receptor 5,TGR5)的相互作用影响了这些代谢性疾病。FXR主要通过影响胆汁酸的合成及转运对非酒精性脂肪肝发挥作用,TGR5则是间接增加褐色脂肪组织中的生热作用,改善肥胖和2型糖尿病。这些调控机制的研究是非常必要的。本文综述了胆汁酸代谢及其对代谢性疾病调控的分子机制的研究进展,以期为科研工作者提供一定的参考。 相似文献
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肝功能衰竭并发感染与肠道细菌易位 总被引：15，自引：2，他引：15
李兰娟 《中国微生态学杂志》2001,13(2):63-65
肝功能衰竭患者易并发内毒素血症、细菌及真菌感染。细菌学检查证实 80 %的急性肝功能衰竭患者有细菌感染 ,32 %的病人有真菌感染 ,肺、血液及尿路是其主要感染部位 ,且这些感染主要发生在急性肝功能衰竭的早期 (4天内 ) ,其中 6 0 %的病人死于细菌感染 [1 ] 。在慢性肝功能衰竭者 ,5 0 %的患者死于细菌感染。研究表明 ,肝功能衰竭并发感染的主要病原菌为革兰阴性肠道细菌 [2 ] 。肝功能衰竭者易并发感染的主要原因与其体液、细胞免疫防御功能受损有关。肝功能衰竭时 ,通常补体合成严重不足 ;多形核白细胞移动、吞噬及细胞内杀菌功能下降 ;… 相似文献
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回肠Na^ ／胆汁酸转运体是位于回肠末端、特异性吸收胆汁酸的一种Na^ 依赖性胆汁酸联合转运蛋白。该转运蛋白结构和功能的改变会引起胆汁酸叶收异常,进而影响到胆固醇和脂类的吸收。对该转运体及其抑制剂的研究,是寻找具有新作用机制降胆固醇的一条有效途径,目前正在受到人们的重视。 相似文献
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胆汁酸作为胆固醇代谢的副产物,除具有调节脂质消化及胆固醇代谢等功能外,对心脏功能也有一定的影响。不同的胆汁酸对心脏功能的影响及作用程度不同,熊去氧胆酸对心肌细胞具有保护作用,可改善心力衰竭病人的心血管功能。牛磺胆酸及甘氨胆酸均可影响心肌细胞的收缩,使心肌细胞发生负性变时性、变力性传导作用。未成熟心肌细胞较成熟心肌细胞更易受到胆汁酸的影响。此外发现,心肌细胞上具有毒蕈碱受体(muscarine receptor,MR)及胆汁酸转运体,且胆汁酸可通过M2型毒蕈碱受体抑制心肌细胞的收缩。现就胆汁酸对心功能的影响及调节机制的研究进展从动物水平、细胞水平、分子水平做一综述。 相似文献
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Alesia Walker Barbara Pfitzner Susanne Neschen Melanie Kahle Mourad Harir Marianna Lucio Franco Moritz Dimitrios Tziotis Michael Witting Michael Rothballer Marion Engel Michael Schmid David Endesfelder Martin Klingenspor Thomas Rattei Wolfgang zu Castell Martin Hrabé de Angelis Anton Hartmann Philippe Schmitt-Kopplin 《The ISME journal》2014,8(12):2380-2396
A combinatory approach using metabolomics and gut microbiome analysis techniques was performed to unravel the nature and specificity of metabolic profiles related to gut ecology in obesity. This study focused on gut and liver metabolomics of two different mouse strains, the C57BL/6J (C57J) and the C57BL/6N (C57N) fed with high-fat diet (HFD) for 3 weeks, causing diet-induced obesity in C57N, but not in C57J mice. Furthermore, a 16S-ribosomal RNA comparative sequence analysis using 454 pyrosequencing detected significant differences between the microbiome of the two strains on phylum level for Firmicutes, Deferribacteres and Proteobacteria that propose an essential role of the microbiome in obesity susceptibility. Gut microbial and liver metabolomics were followed by a combinatory approach using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and ultra performance liquid chromatography time of tlight MS/MS with subsequent multivariate statistical analysis, revealing distinctive host and microbial metabolome patterns between the C57J and the C57N strain. Many taurine-conjugated bile acids (TBAs) were significantly elevated in the cecum and decreased in liver samples from the C57J phenotype likely displaying different energy utilization behavior by the bacterial community and the host. Furthermore, several metabolite groups could specifically be associated with the C57N phenotype involving fatty acids, eicosanoids and urobilinoids. The mass differences based metabolite network approach enabled to extend the range of known metabolites to important bile acids (BAs) and novel taurine conjugates specific for both strains. In summary, our study showed clear alterations of the metabolome in the gastrointestinal tract and liver within a HFD-induced obesity mouse model in relation to the host–microbial nutritional adaptation. 相似文献
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《Journal of lipid research》2017,58(6):1143-1152
In addition to functioning as detergents that aid digestion of dietary lipids in the intestine, some bile acids have been shown to exhibit antimicrobial activity. However, detailed information on the bactericidal activities of the diverse molecular species of bile acid in humans and rodents is largely unknown. Here, we investigated the toxicity of 14 typical human and rodent free bile acids (FBAs) by monitoring intracellular pH, membrane integrity, and viability of a human intestinal bacterium, Bifidobacterium breve Japan Collection of Microorganisms (JCM) 1192T, upon exposure to these FBAs. Of all FBAs evaluated, deoxycholic acid (DCA) and chenodeoxycholic acid displayed the highest toxicities. Nine FBAs common to humans and rodents demonstrated that α-hydroxy-type bile acids are more toxic than their oxo-derivatives and β-hydroxy-type epimers. In five rodent-specific FBAs, β-muricholic acid and hyodeoxycholic acid showed comparable toxicities at a level close to DCA. Similar trends were observed for the membrane-damaging effects and bactericidal activities to Blautia coccoides JCM 1395T and Bacteroides thetaiotaomicron DSM 2079T, commonly represented in the human and rodent gut microbiota. These findings will help us to determine the fundamental properties of FBAs and better understand the role of FBAs in the regulation of gut microbiota composition. 相似文献
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《Cell metabolism》2021,33(10):1988-2003.e7
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Xiaolin Wang Lu Chen Hui Wang Wei Cai Qing Xie 《Journal of cellular and molecular medicine》2020,24(4):2573-2581
Chronic hepatitis B (CHB) is a global epidemic disease that may progress to fibrosis, cirrhosis and hepatocellular carcinoma. The role of the liver‐bile acid‐microbiota axis in CHB remains unclear. The aims of this study are to elucidate the alteration of the gut microbiota and its functions in bile acid homeostasis in CHB patients with different degrees of fibrosis. In the present study, we evaluated serum and faecal bile acid profiles in healthy controls and CHB patients with biopsy‐proven diagnosis: patients had stage 0‐1 fibrosis were classified as mild CHB and patients had stage 2‐4 fibrosis were classified as moderate/advanced CHB. The levels of serum total bile acids (BAs) and primary BAs were increased in CHB patients with moderate/advanced fibrosis, whereas faecal total and secondary BAs levels were significantly lower. Analyses of gut microbiota exhibited a trend of decreased abundance in bacteria genera responsible for BA metabolism in CHB patients with moderate/advanced fibrosis. CHB is associated with altered bile acid pool which is linked with the dysregulated gut microbiota. The higher level of FGF‐19 may act in a negative feedback loop for maintaining the bile acid homeostasis. 相似文献
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The gut microbiota is profoundly involved in glucose and lipid metabolism,in part by regulating bile acid(BA)metabolism and affecting multiple BA-receptor signaling pathways.BAs are synthesized in the liver by multi-step reactions catalyzed via two distinct routes,the classical pathway(producing the 12α-hy-droxylated primary BA,cholic acid),and the alternative pathway(producing the non-12α-hydroxylated primary BA,chenodeoxycholic acid).BA synthesis and excre-tion is a major pathway of cholesterol and lipid cata-bolism,and thus,is implicated in a variety of metabolic diseases including obesity,insulin resis-tance,and nonalcoholic fatty liver disease.Addition-ally,both oxysterols and BAs function as signaling molecules that activate multiple nuclear and mem-brane receptor-mediated signaling pathways in various tissues,regulating glucose,lipid homeostasis,inflam-mation,and energy expenditure.Modulating BA syn-thesis and composition to regulate BA signaling is an interesting and novel direction for developing thera-pies for metabolic disease.In this review,we sum-marize the most recent findings on the role of BA synthetic pathways,with a focus on the role of the alternative pathway,which has been under-investi-gated,in treating hyperglycemia and fatty liver dis-ease.We also discuss future perspectives to develop promising pharmacological strategies targeting the alternative BA synthetic pathway for the treatment of metabolic diseases. 相似文献
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Germ-free mice were orally inoculated with human intestinal 7alpha-dehydroxylating bacterial strains to evaluate their ability to transform bile acids in vivo. Three weeks after inoculation of the bacteria, cecal bile acids were examined. Among free-form bile acids, only beta-muricholic acid was detected in the cecal contents of gnotobiotic mice associated with Bacteroides distasonis strain K-5. No secondary bile acid was observed in the cecal contents of any of the gnotobiotic mice associated with 7alpha-dehydroxylating bacteria, Clostridium species strain TO-931 or Eubacterium species strain 36S. 相似文献
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Yating Luo Ruyue Cheng Huijing Liang Zhonghua Miao Jiani Wang Qingqing Zhou Jianguo Chen Fang He Xi Shen 《Experimental Animals》2022,71(4):468
In this study, C57BL/6J male mice were fed normal chow (NC; control) or a high-fat diet (HFD) for 12 weeks, and HFD mice were supplemented with oral administration of Streptococcus thermophilus MN-ZLW-002 (HFD + MN002); n=20/group. Body weight, visceral fat, blood glucose, blood lipids and liver lipid deposition increased in the HFD group, and the composition of gut microbiota, cecum short-chain fatty acids and fecal bile acids (BAs) also changed. Oral-fed MN-002 increased the relative abundances of Ruminococcaceae, Lachnospiraceae and Streptococcaceae and improved blood glucose, liver cholesterol deposition, and serum IL-10, CCL-3 and the fecal BAs composition. In conclusion, the high-fat diet changed the composition of bile acids by shaping the gut microbiota into an obese type, leading to metabolic disturbances. Streptococcus thermophilus MN-ZLW-002 regulated gut microbiota by adjusting the composition of bile acids and improved the perturbation caused by high-fat diets. However, the effect of MN002 observed in animal experiments needs to be verified by long-term clinical trials. 相似文献