肥胖孕妇肠道菌群与子代肥胖的相关性

妊娠期肥胖发生率在世界范围内呈上升趋势,成为影响人类健康的公共卫生问题。肥胖母亲肠道菌群失调导致婴儿早期定植菌群异常,而婴儿早期菌群定植情况与其日后生长发育密切相关,容易导致成年后出现肥胖、胰岛素抵抗、代谢综合征等疾病。因此针对肥胖孕妇肠道菌群分析,以及婴儿肠道菌群及生长发育的分析,对于孕妇孕期管理、健康宣教提高国民整体身体素质具有重要意义。     

Habitat fragmentation is associated with dietary shifts and microbiota variability in common vampire bats

Host ecological factors and external environmental factors are known to influence the structure of gut microbial communities, but few studies have examined the impacts of environmental changes on microbiotas in free‐ranging animals. Rapid land‐use change has the potential to shift gut microbial communities in wildlife through exposure to novel bacteria and/or by changing the availability or quality of local food resources. The consequences of such changes to host health and fitness remain unknown and may have important implications for pathogen spillover between humans and wildlife. To better understand the consequences of land‐use change on wildlife microbiotas, we analyzed long‐term dietary trends, gut microbiota composition, and innate immune function in common vampire bats (Desmodus rotundus) in two nearby sites in Belize that vary in landscape structure. We found that vampire bats living in a small forest fragment had more homogenous diets indicative of feeding on livestock and shifts in microbiota heterogeneity, but not overall composition, compared to those living in an intact forest reserve. We also found that irrespective of sampling site, vampire bats which consumed relatively more livestock showed shifts in some core bacteria compared with vampire bats which consumed relatively less livestock. The relative abundance of some core microbiota members was associated with innate immune function, suggesting that future research should consider the role of the host microbiota in immune defense and its relationship to zoonotic infection dynamics. We suggest that subsequent homogenization of diet and habitat loss through livestock rearing in the Neotropics may lead to disruption to the microbiota that could have downstream impacts on host immunity and cross‐species pathogen transmission.     

Presence of Blastocystis in gut microbiota is associated with cognitive traits and decreased executive function

Growing evidence implicates the gut microbiome in cognition. Blastocystis is a common gut single-cell eukaryote parasite frequently detected in humans but its potential involvement in human pathophysiology has been poorly characterized. Here we describe how the presence of Blastocystis in the gut microbiome was associated with deficits in executive function and altered gut bacterial composition in a discovery (n = 114) and replication cohorts (n = 942). We also found that Blastocystis was linked to bacterial functions related to aromatic amino acids metabolism and folate-mediated pyrimidine and one-carbon metabolism. Blastocystis-associated shifts in bacterial functionality translated into the circulating metabolome. Finally, we evaluated the effects of microbiota transplantation. Donor’s Blastocystis subtypes led to altered recipient’s mice cognitive function and prefrontal cortex gene expression. In summary, Blastocystis warrant further consideration as a novel actor in the gut microbiome-brain axis.Subject terms: Biomarkers, Pathogenesis, Diagnosis     

肥胖相关的肠道微生物群落结构动力学与功能解析研究

肥胖及相关的慢性代谢性疾病近年来已经成为威胁全球的公共健康问题。越来越多的证据表明,在宿主的营养、免疫和代谢中有不可替代的作用的肠道菌群不仅可以通过调节宿主脂肪吸收存储相关的基因,影响后者的能量平衡,更重要的是其结构失调导致宿主循环系统中内毒素增加,诱发慢性、低水平炎症,导致肥胖和胰岛素抵抗。运用微生物分子生态学、元基因组学和代谢组学的方法,揭示与代谢性疾病相关的菌群结构失调,并鉴定出相关的特定细菌类群及其功能,使得通过以菌群为靶点的营养干预手段防止慢性代谢性疾病成为可能,将带来代谢性疾病预防和控制策略的革命性的变化。     

Maternal obesity is associated with gut microbial metabolic potential in offspring during infancy

Children born to obese mothers are at increased risk for obesity, but the mechanisms behind this association are not fully understood. Our study aimed to investigate differences in the functions encoded by the microbiome of infants at 18 months of age when the transition from early infant-feeding to solid family foods is established. To investigate the impact of maternal prepregnancy body mass index on infants’ gut microbiome, faecal samples from infants born to normoweight (n = 21) and obese mothers (n = 18) were analysed by 16S rRNA gene sequencing and a functional-inference-based microbiome analysis. Our results indicated that Firmicutes was significantly enriched in infants born to normoweight mothers whereas Bacteroidetes was significantly enriched in infants born to obese women. In both microbiomes, the greatest number of genes (>50%) that were assigned a function encoded for proteins involved in “metabolism” among tier 1 KEGG Orthology (KO) categories. At lower KO functional categories, the microbiome of infants born to normoweight mothers was characterized by a significant enrichment in the abundances of “pentose phosphate pathway” (p = 0.037), “lysine biosynthesis” (p = 0.043), “glycerolipid metabolism” (p = 0.042), and “C5-branched dibasic acid metabolism” (p = 0.045). Notably, the microbiome of infants born to obese mothers was significantly enriched in “streptomycin biosynthesis” (p = 0.047), “sulphur metabolism” (p = 0.041), “taurine and hypotaurine metabolism” (p = 0.036), and “lipopolysaccharide biosynthesis” (p = 0.043). In summary, our study showed that maternal prepregnancy obesity may imprint a selective gut microbial composition during late infancy with distinct functional performances.     

Dysbiosis of gut microbiota was closely associated with psoriasis

Psoriasis is an autoimmune disease and gut microbiota participate in the establishment of intestinal immunity. This study was performed to identify the fecal microbial composition of psoriasis patients, and investigated the influence of subgroup(type and severity) on the fecal microbial composition, and to define the key microbiota in the pathogenesis of psoriasis. Fecal samples from 35 psoriasis patients and 27 healthy controls were sequenced by 16 S rRNA and then analyzed by informatics methods. We found that the microbiota of the psoriasis group differed from that of the heathy group. The relative abundances of Firmicutes and Bacteroidetes were inverted at the phylum level, and 16 kinds of phylotype at the genus level were found with significant difference. No microbial diversity and composition alteration were observed among the four types of psoriasis. The microbiota of psoriasis patients in the severe state differs from those of psoriasis patients with more mild conditions and also the healthy controls. The veillonella in fecal microbiota showed a positive relationship with h-CRP in blood. This research proved that psoriasis patients have a significant disturbed microbiota profiles. Further study of psoriasis based on microbiota may provide novel insights into the pathogenesis of psoriasis and more evidence for the prevention and treatment of psoriasis.     

Molecular analysis of gut microbiota in obesity among Indian individuals

Obesity is a consequence of a complex interplay between the host genome and the prevalent obesogenic factors among the modern communities. The role of gut microbiota in the pathogenesis of the disorder was recently discovered; however, 16S-rRNA-based surveys revealed compelling but community-specific data. Considering this, despite unique diets, dietary habits and an uprising trend in obesity, the Indian counterparts are poorly studied. Here, we report a comparative analysis and quantification of dominant gut microbiota of lean, normal, obese and surgically treated obese individuals of Indian origin. Representative gut microbial diversity was assessed by sequencing fecal 16S rRNA libraries for each group (n=5) with a total of over 3000 sequences. We detected no evident trend in the distribution of the predominant bacterial phyla, Bacteroidetes and Firmicutes. At the genus level, the bacteria of genus Bacteroides were prominent among the obese individuals, which was further confirmed by qPCR (P less than 0.05). In addition, a remarkably high archaeal density with elevated fecal SCFA levels was also noted in the obese group. On the contrary, the treated-obese individuals exhibited comparatively reduced Bacteroides and archaeal counts along with reduced fecal SCFAs. In conclusion, the study successfully identified a representative microbial diversity in the Indian subjects and demonstrated the prominence of certain bacterial groups in obese individuals; nevertheless, further studies are essential to understand their role in obesity.     

Major shifts in gut microbiota during development and its relationship to growth in ostriches

The development of gut microbiota during ontogeny is emerging as an important process influencing physiology, immunity and fitness in vertebrates. However, knowledge of how bacteria colonize the juvenile gut, how this is influenced by changes in the diversity of gut bacteria and to what extent this influences host fitness, particularly in nonmodel organisms, is lacking. Here we used 16S rRNA gene sequencing to describe the successional development of the faecal microbiome in ostriches (Struthio camelus, n = 66, repeatedly sampled) over the first 3 months of life and its relationship to growth. We found a gradual increase in microbial diversity with age that involved multiple colonization and extinction events and a major taxonomic shift in bacteria that coincided with the cessation of yolk absorption. Comparisons with the microbiota of adults (n = 5) revealed that the chicks became more similar in their microbial diversity and composition to adults as they aged. There was a five‐fold difference in juvenile growth during development, and growth during the first week of age was strongly positively correlated with the abundance of the genus Bacteroides and negatively correlated with Akkermansia. After the first week, the abundances of six phylogenetically diverse families (Peptococcaceae, S24‐7, Verrucomicrobiae, Anaeroplasmataceae, Streptococcaceae, Methanobacteriaceae) were associated with subsequent reductions in chick growth in an age‐specific and transient manner. These results have broad implications for our understanding of the development of gut microbiota and its associations with animal growth.     

Meta-analyses of human gut microbes associated with obesity and IBD

Recent studies have linked human gut microbes to obesity and inflammatory bowel disease, but consistent signals have been difficult to identify. Here we test for indicator taxa and general features of the microbiota that are generally consistent across studies of obesity and of IBD, focusing on studies involving high-throughput sequencing of the 16S rRNA gene (which we could process using a common computational pipeline). We find that IBD has a consistent signature across studies and allows high classification accuracy of IBD from non-IBD subjects, but that although subjects can be classified as lean or obese within each individual study with statistically significant accuracy, consistent with the ability of the microbiota to experimentally transfer this phenotype, signatures of obesity are not consistent between studies even when the data are analyzed with consistent methods. The results suggest that correlations between microbes and clinical conditions with different effect sizes (e.g. the large effect size of IBD versus the small effect size of obesity) may require different cohort selection and analysis strategies.     

Modeling shifts in microbial populations associated with health or disease

Stable microbial communities associated with health can be disrupted by altered environmental conditions. Periodontal diseases are associated with changes in the resident oral microflora. For example, as gingivitis develops, a key change in the microbial composition of dental plaque is the ascendancy of Actinomyces spp. and gram-negative rods at the expense of Streptococcus spp. We describe the use of an in vitro model to replicate this population shift, first with a dual-species model (Actinomyces naeslundii and Streptococcus sobrinus) and then using a microcosm model of dental plaque. The population shift was induced by environmental changes associated with gingivitis, first by the addition of artificial gingival crevicular fluid and then by a switch to a microaerophilic atmosphere. In addition to the observed population shifts, confocal laser scanning microscopy also revealed structural changes and differences in the distribution of viable and nonviable bacteria associated with the change in environmental conditions. This model provides an appropriate system for the further understanding of microbial population shifts associated with gingivitis and for the testing of, for example, antimicrobial agents.     

Anti-obesity effects of gut microbiota are associated with lactic acid bacteria

The prevalence of obesity is rapidly becoming endemic in industrialized countries and continues to increase in developing countries worldwide. Obesity predisposes people to an increased risk of developing metabolic syndrome. Recent studies have described an association between obesity and certain gut microbiota, suggesting that gut microbiota might play a critical role in the development of obesity. Although probiotics have many beneficial health effects in humans and animals, attention has only recently been drawn to manipulating the gut microbiota, such as lactic acid bacteria (LAB), to influence the development of obesity. In this review, we first describe the causes of obesity, including the genetic and environmental factors. We then describe the relationship between the gut microbiota and obesity, and the mechanisms by which the gut microbiota influence energy metabolism and inflammation in obesity. Lastly, we focus on the potential role of LAB in mediating the effects of the gut microbiota in the development of obesity.     

Bacterial translocation in cirrhosis is not caused by an abnormal small bowel gut microbiota

Sepsis is common in liver cirrhosis, and animal studies have shown the gut to be the principal source of infection, through bacterial overgrowth and translocation in the small bowel. A total of 33 patients were recruited into this study, 10 without cirrhosis and 23 with cirrhotic liver disease. Six distal duodenal biopsies were obtained and snap frozen for RNA and DNA extraction, or frozen for FISH. Peripheral venous bloods were obtained from 30 patients, including 17 chronic liver disease patients. Samples were analysed by real-time PCR, to assess total bacteria, bifidobacteria, bacteroides, enterobacteria, staphylococci, streptococci, lactobacilli, enterococci, Helicobacter pylori and moraxella, as well as TNF-α, IL-8 and IL-18. There was no evidence of bacterial overgrowth with respect to any of the individual bacterial groups, with the exception of enterococci, which were present in higher numbers in cirrhotic patients (P?=?0.04). There were no significant differences in any of the cytokines compared to the controls. The small intestinal mucosal microbiota in cirrhotic patients was qualitatively and quantitatively normal, and this shifts the focus of disease aetiology to factors that reduce gut integrity, failure of mechanisms to remove translocating bacteria, or the large bowel as the source of sepsis.     

Web of ecological interactions in an experimental gut microbiota

The dynamics of all ecosystems are dictated by intrinsic, density‐dependent mechanisms and by density‐independent environmental forcing. In spite of the importance of the gastrointestinal microbiota in health and disease, the ecology of this system remains largely unknown. Here, we take an ecological approach to gut microbial community analysis, with statistical modelling of time series data from chemostats. This approach removes effects of host forcing, allowing us to describe a network of intrinsic interactions determining the dynamic structure of an experimental gut microbiota. Surprisingly, the main colonization pattern in this simplified model system resembled that of the human infant gut, suggesting a potentially important role of density‐dependent interactions in the early gut microbiota. Knowledge of ecological structures in microbial systems may provide us with a means of controlling such systems by modifying the strength and nature of interactions among microbes and between the microbes and their environment.     

Relationship between gut microbiota and development of T cell associated disease

The interplay between the immune response and the gut microbiota is complex. Although it is well-established that the gut microbiota is essential for the proper development of the immune system, recent evidence indicates that the cells of the immune system also influence the composition of the gut microbiota. This interaction can have important consequences for the development of inflammatory diseases, including autoimmune diseases and allergy, and the specific mechanisms by which the gut commensals drive the development of different types of immune responses are beginning to be understood. Furthermore, sex hormones are now thought to play a novel role in this complex relationship, and collaborate with both the gut microbiota and immune system to influence the development of autoimmune disease. In this review, we will focus on recent studies that have transformed our understanding of the importance of the gut microbiota in inflammatory responses.