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Artificial Sweeteners Induce Glucose Intolerance by Altering the Gut Microbiota
Abstract and Figures
Non-caloric artificial sweeteners (NAS) are among the most widely used food additives worldwide, regularly consumed by lean and obese individuals alike. NAS consumption is considered safe and beneficial owing to their low caloric content, yet supporting scientific data remain sparse and controversial. Here we demonstrate that consumption of commonly used NAS formulations drives the development of glucose intolerance through induction of compositional and functional alterations to the intestinal microbiota. These NAS-mediated deleterious metabolic effects are abrogated by antibiotic treatment, and are fully transferrable to germ-free mice upon faecal transplantation of microbiota configurations from NAS-consuming mice, or of microbiota anaerobically incubated in the presence of NAS. We identify NAS-altered microbial metabolic pathways that are linked to host susceptibility to metabolic disease, and demonstrate similar NAS-induced dysbiosis and glucose intolerance in healthy human subjects. Collectively, our results link NAS consumption, dysbiosis and metabolic abnormalities, thereby calling for a reassessment of massive NAS usage.
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... Secondly, higher UPF consumption is inversely associated with a poor nutritional profile and quality and deficiency intake of dietary fiber, fruit, vegetables, and legumes [43]. In addition, ingredients in UPFs such as artificial sweeteners could result in dysbiosis of gut microbiota, glucose intolerance, insulin resistance, and diverse metabolic disturbance, which then leads to the development of MetS [44,45]. Thirdly, the physical properties of food were altered by a series of industrial processes, which could result in a higher glycemic load and reduction of gut-brain satiety signaling [46,47]. ...
The prevalence of metabolic syndrome (MetS) is increasing and the relationship between ultra-processed food (UPF) consumption and MetS remains uncertain in Chinese adults. This study aimed to examine the longitudinal association of UPF consumption with the risk of MetS and its components in Chinese adults. Adults aged 18 years and above who participated in at least two waves of the China Health and Nutrition Survey (CHNS) in 2009, 2015, and 2018 were included in this analysis. Dietary intake data were collected by three consecutive 24 h dietary recalls and weighing household foods and condiments. Depending on the purpose and extent of food processing, UPFs were classified using the NOVA food classification system. A multivariate Cox proportional risk model was used to explore the association between UPF consumption (grouped by quartile: quartile 1 (Q1), quartile 2 (Q2), quartile 3 (Q3), and quartile 4 (Q4)) and risk of MetS and its components. A total of 5147 adults were included. During a median (IQR) 6.0 (3.0, 9.0) year follow-up with 31,878 person-years, 1712 MetS cases were identified, with an incidence of 33.26%. After multivariable adjustment, the risk of MetS was increased by 17% in the highest quartile with UPF consumption (HR: 1.17, 95% CI: 1.01–1.35, p trend: 0.047), with the lowest quartile as a reference. For the components of MetS, the risk of central obesity, raised triglycerides (TG), reduced high-density lipoprotein cholesterol (HDL-C), and raised blood pressure (BP) was increased by 33% (HR: 1.33, 95% CI: 1.18–1.51, p trend: <0.001), 26% (HR: 1.26, 95% CI: 1.08–1.48, p trend: 0.003), 25% (HR: 1.25, 95% CI: 1.07–1.46, p trend: 0.007), and 16% (HR: 1.16, 95% CI: 1.03–1.32, p trend: 0.018) in the highest quartile with UPF consumption, respectively. Adults aged 45–59 years and living in urban areas with higher UPF consumption had higher odds of MetS. These results indicate that higher long-term UPF consumption was associated with an increased risk of MetS in Chinese adults. Further studies such as intervention trials are needed to confirm the mechanism of correlation between UPF consumption and health-related outcomes. Nutritional education actions are warranted to promote a balanced diet and improve the overall dietary quality of residents to reduce the risk of MetS effectively.
... 76+ As and BRB+ As groups were exposed to As via drinking water (10 ppm) after 2 weeks. Mice of 30 g have an average daily water intake of 2 ml [24]. After another 4 weeks of As treatment, fecal samples were collected individually, and stored at −80 °C for further experiments. ...
Mounting evidence has linked berries to a variety of health benefits. We previously reported that administration of a diet rich in black raspberries (BRBs) impacted arsenic (As) biotransformation and reduced As-induced oxidative stress. To further characterize the role of the gut microbiota in BRB-mediated As toxicity, we utilized the dietary intervention of BRBs combined with a mouse model to demonstrate microbial changes by examining associated alterations in the gut microbiota, especially its functional metabolites. Results showed that BRB consumption changed As-induced gut microbial alterations through restoring and modifying the gut microbiome, including its composition, functions and metabolites. A number of functional metabolites in addition to bacterial genera were significantly altered, which may be linked to the effects of BRBs on arsenic exposure. Results of the present study suggest functional interactions between dietary administration of black raspberries and As exposure through the lens of the gut microbiota, and modulation of the gut microbiota and its functional metabolites could contribute to effects of administration of BRBs on As toxicity.
... A large number of Gram-positive bacteria in the body are related to the cause of cellular senescence and liver cancer onset, and the consumption of a high-fat diet changes the gut microbiota [145]. The excess consumption of sweeteners induces dysbiosis [146]. Dysbiosis induced by high-fructose consumption is responsible for the induction of metabolic syndrome [147]. ...
In recent years, attention has focused on the roles of phytochemicals in fruits and vegetables in maintaining and improving the intestinal environment and preventing metabolic syndrome. A high-fat and high-sugar diet, lack of exercise, and excess energy accumulation in the body can cause metabolic syndrome and induce obesity, diabetes, and disorders of the circulatory system and liver. Therefore, the prevention of metabolic syndrome is important. The current review shows that the simultaneous intake of phytochemicals contained in citruses and grapes together with vitamin D improves the state of gut microbiota and immunity, preventing metabolic syndrome and related diseases. Phytochemicals contained in citruses include polyphenols such as hesperidin, rutin, and naringin; those in grapes include quercetin, procyanidin, and oleanolic acid. The intake of these phytochemicals and vitamin D, along with prebiotics and probiotics, nurture good gut microbiota. In general, Firmicutes are obese-prone gut microbiota and Bacteroidetes are lean-prone gut microbiota; good gut microbiota nurture regulatory T cells, which suppress inflammatory responses and upregulate immunity. Maintaining good gut microbiota suppresses TNF-α, an inflammatory cytokine that is also considered to be a pathogenic contributor adipokine, and prevents chronic inflammation, thereby helping to prevent metabolic syndrome. Maintaining good gut microbiota also enhances adiponectin, a protector adipokine that prevents metabolic syndrome. For the prevention of metabolic syndrome and the reduction of various disease risks, the intake of phytochemicals and vitamin D will be important for human health in the future.
... In order to interpret such rapid growth from 2013 to 2021, we have explored the Altmetric Top 100 over the years, which includes the top 100 studies with the highest AAS of the year. It is found that from 2013 to 2015, there was one article each year discussing gut microbiota and reaching the annual Altmetric Top 100, the titles of which are "Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis" (Koeth et al., 2013), "Artificial sweeteners induce glucose intolerance by altering the gut microbiota (Suez et al., 2014), " and "Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome (Chassaing et al., 2015)." Their AASs are 1089, 4794, and 1835, while their annual ranks are 64, 3, and 57 respectively (Supplementary Figure S1). ...
Background
Rheumatic diseases (RD) are a group of multi-system inflammatory autoimmune diseases whose causes are still under study. In the past few decades, researchers have found traces of the association between rheumatic diseases and intestinal microbiota, which can partially explain the pathogenesis of rheumatic diseases. We aimed to describe the research trend and main divisions on how gut flora interreacts with rheumatic diseases, and discussed about the possible clinical applications.
Methods
We analyzed bibliometric data from the Web of Science core collection (dated 15th May 2022). Biblioshiny R language software packages (bibliometrix) were used to obtain the annual publication and citations, core sources according to Bradford’s law, and country collaboration map. We designed and verified the keyword co-occurrence network and strategic diagram with the help of VOSviewer and CiteSpace, subdivided the research topic into several themes and identified research dimensions. The tables of most local cited documents and core sources were processed manually. Furthermore, the Altmetric Attention Score and the annual Altmetric Top 100 were applied to analyze the annual publication and citation.
Results
From a total of 541 documents, we found that the overall trend of annual publication and citation is increasing. The major research method is to compare the intestinal microbial composition of patients with certain rheumatic disease and that of the control group to determine microbial alterations related to the disease’s occurrence and development. According to Bradford’s law, the core sources are Arthritis and Rheumatology, Annals of the Rheumatic Diseases, Current Opinion in Rheumatology, Nutrients, Rheumatology, and Journal of Rheumatology. Since 1976, 101 countries or regions have participated in studies of rheumatology and intestinal microbes. The United States ranks at the top and has the broadest academic association with other countries. Five themes were identified, including the pivotal role of inflammation caused by intestinal bacteria in the rheumatic pathogenesis, the close relationship between rheumatic diseases and inflammatory bowel disease, immunoregulation mechanism as a mediator of the interaction between rheumatic diseases and gut flora, dysbiosis and decreased diversity in intestine of patients with rheumatic diseases, and the influence of oral flora on rheumatic diseases. Additionally, four research dimensions were identified, including pathology, treatment, disease, and experiments.
Conclusion
Studies on rheumatic diseases and the intestinal microbiota are growing. Attention should be paid to the mechanism of their interaction, such as the microbe-immune-RD crosstalk. Hopefully, the research achievements can be applied to diseases’ prevention, diagnosis, and treatment, and our work can contribute to the readers’ future research.
... A 2015 study showed that jet lag-induced dysbiosis can promote glucose intolerance and obesity, which can be transferred to GF mice after FMT [43]. Two articles published in Nature confrmed that artifcial sweeteners can cause glucose intolerance by modulating the GM [44], and dietary emulsifers can afect the GM in mice to promote colitis and metabolic syndrome [45], which were confrmed by FMT experiments. (4) Cardiovascular and cerebrovascular diseases: It was observed that hypertension can be transferred through FMT from hypertensive human donors to GF mice, demonstrating the direct efect of GM on host blood pressure [46]. ...
Background:
Fecal microbiota transplantation (FMT) is a current research hotspot, with a surge in the output of publications over the past decade. This study dedicates to the exploration of the research status and highlights significant themes and future trends in FMT research with the aid of bibliometric analysis.
Methods:
FMT publications from 2012 to 2021 were retrieved on August 12, 2022, using the SCI-Expanded of Web of Science (WoS). The Bibliometrix in R program, Microsoft Office Excel, VOSviewer, and CiteSpace were utilized for bibliometrics and visual analysis, revealing the main publications, journals, countries, agencies, authors, and keywords distribution in FMT research.
Results:
There were 2,931 papers included. FMT research presented a growing trend from 2012 to 2021. The countries with the most publications and contributions in FMT area were China and the United States. The high-yield institutions were Harvard University, Udice French Research Universities, and the University of California System. The primary authors were Nieuwdorp Max, Allegretti Jessica R, and Kassam Zain. Frontiers in Microbiology and Science were the top-ranked journals in publications and total citations, respectively. The important topics primarily included FMT-related mechanisms and the usage of FMT in Clostridium difficile infection (CDI), inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), metabolic disease, neurological disorders, and psychiatric disorders. Future research would primarily concentrate on neurological disorders, chemotherapy and immunotherapy for malignant tumors, and FMT-related consensus and guidelines.
Conclusion:
With the help of bibliometric analysis, we were able to obtain the understanding of the status and trends of global FMT-related research. The field of FMT is undergoing tremendous progress, and our findings can guide clinical researchers' and practitioners' future work in the rapidly evolving field of FMT.
Diet-derived polysaccharides are an important carbon source for gut bacteria and shape the human gut microbiome. Acarbose, a compound used clinically to treat type 2 diabetes, is known to inhibit the growth of some bacteria on starches based on its activity as an inhibitor of α-glucosidases and α-amylases. In contrast to acarbose, montbretin A, a new drug candidate for the treatment of type 2 diabetes, has been reported to be more specific for the inhibition of α-amylase, notably human pancreatic α-amylase. However, the effects of both molecules on glycan metabolism across a larger diversity of human gut bacteria remain to be characterized. Here, we used ex vivo metabolic labeling of a human microbiota sample with fluorescent maltodextrin to identify gut bacteria affected by amylase inhibitors. Metabolic labeling was performed in the presence and absence of amylase inhibitors, and the fluorescently labeled bacteria were identified by fluorescence-activated cell sorting coupled with 16S rDNA amplicon sequencing. We validated the labeling results in cultured isolates and identified four gut bacteria species whose metabolism of maltodextrin is inhibited by acarbose. In contrast, montbretin A slowed the growth of only one species, supporting the fact that it is more selective. Metabolic labeling is a valuable tool to characterize glycan metabolism in microbiota samples and could help understand the untargeted impact of drugs on the human gut microbiota.
Until the mid-90s, sugar had been the main sweetener used by the food industry, but in recent years the promotion for the consumption of artificial sweeteners has increased, including sucralose, which has gained strength and presence, gradually becoming the most widely used artificial sweetener in a variety of products. Health authorities have authorized the implementation of sucralose additives safely as a sweetener, based on numerous analyses, however, there are new studies that have reported some interesting data on its effects on health, this paper is focused on exploring what has been reported on the metabolism, effects and possible health risks related to the consumption of sucralose. These effects include increased intestinal damage and inflammation in animal models with inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease; affections in the intestinal microbial flora, intestinal barrier and inactivation of digestive proteases, caused increase in TNFα, IL-1β as well as a decrease in IL-10 and with this, an increase in the risk for colorectal cancer; Other studies report an association between the intake of this sweetener and the increased risk of cardiovascular events and appetite. This new evidence raises the need to develop new nutritional strategies, as well as monitoring the proportion and type of compounds that are ingested in industrialized products. At the end of the day, the principles of a healthy diet will always prevail over the alternatives of artificial manipulation.
Context
The continuous rise in urbanisation and its associated factors have been reflected in the structure of the human gut ecosystem.
Objective
The main focus of the review is to discuss and summarise the major risk factors associated with urbanisation that affects human gut microbiota thus affecting human health.
Methods
Multiple medical literature databases, namely PubMed, Google, Google Scholar, and Web of Science were used to find relevant materials for urbanization and its major factors affecting human gut microbiota/microbiome. Both layman and Medical Subject Headings (MeSH) terms were used in the search. Due to the scarcity of the data, no limitation was set on the publication date. Relevant material in the English language which includes case reports, chapters of books, journal articles, online news reports and medical records was included in this review.
Results
Based on the data discussed in the review, it is quite clear that urbanisation and its associated factors have long-standing effects on the human gut microbiota that result in alterations of gut microbial diversity and composition. This is a matter of serious concern as chronic inflammatory diseases are on the rise in urbanised societies.
Conclusion
A better understanding of the factors associated with urbanisation will help us to identify and implement new biological and social approaches to prevent and treat diseases and improve health globally by deepening our understanding of these relationships and increasing studies across urbanisation gradients.
• HIGHLIGHTS
• Human gut microbiota has been linked to almost every important function, including metabolism, intestinal homeostasis, immune system, biosynthesis of vitamins, brain processes, and its behaviour.
• However, dysbiosis i.e., alteration in the composition and diversity of gut microbiota is associated with the pathogenesis of many chronic conditions.
• In the 21st century, urbanisation represents a major demographic shift in developed and developing countries.
• During this period of urbanisation, humans have been exposed to many environmental exposures, all of which have led to the dysbiosis of human gut microbiota.
• The main focus of the review is to discuss and summarize the major risk factors associated with urbanisation and how it affects the diversity and composition of gut microbiota which ultimately affects human health.
Clarifying the risk factors and mechanisms that contribute to the onset of cognitive impairment following estrogen depletion is essential for improving the quality of life of older females. In the current study, using behavioral tests, 16S rDNA sequencing, in vivo and in vitro electrophysiology, optogenetics and chemogenetics, we found that high-fat diet (HFD)-accelerated impairment of hippocampus-dependent memory, gut microbiota, and hippocampal theta rhythmogenesis in ovariectomized (OVX) mice and fecal microbiota transplantation rescued these phenomena. The identification of fasting-activated medial septal neurons showed that PV⁺ GABAergic neurons in the medial septal area (MSA) respond to gut sensory signals. Optogenetic activation of septohippocampal PV⁺ GABAergic fibers (but not cholinergic fibers) significantly rescued hippocampal theta rhythmogenesis and spatial memory in HFD-fed OVX mice. Resistant starch supplementation (RSHFD) rectified the gut Prevotellaceae and considerably alleviated reduced septal gut-responsive neurons, decreased hippocampal theta rhythm, and impaired hippocampus-dependent memory in HFD-fed OVX mice. Furthermore, chemogenetic inhibition of septal PV⁺ GABAergic neurons reversed the neuroprotective effects of resistant starch supplementation. These findings highlight the notable gut-sensory nature of medial septal PV⁺ GABAergic neurons. A HFD accelerates estrogen deficiency-induced cognitive impairment by disrupting the gut Prevotellaceae-septo-hippocampal pathway. This study contributes to a better understanding of the precise gut-brain control of cognition and cognitive impairment in postmenopausal females.
Assessment and characterization of gut microbiota has become a major research area in human disease, including type 2 diabetes, the most prevalent endocrine disease worldwide. To carry out analysis on gut microbial content in patients with type 2 diabetes, we developed a protocol for a metagenome-wide association study (MGWAS) and undertook a two-stage MGWAS based on deep shotgun sequencing of the gut microbial DNA from 345 Chinese individuals. We identified and validated approximately 60,000 type-2-diabetes-associated markers and established the concept of a metagenomic linkage group, enabling taxonomic species-level analyses. MGWAS analysis showed that patients with type 2 diabetes were characterized by a moderate degree of gut microbial dysbiosis, a decrease in the abundance of some universal butyrate-producing bacteria and an increase in various opportunistic pathogens, as well as an enrichment of other microbial functions conferring sulphate reduction and oxidative stress resistance. An analysis of 23 additional individuals demonstrated that these gut microbial markers might be useful for classifying type 2 diabetes.
Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles.
Emerging next-generation sequencing technologies have revolutionized the collection of genomic data for applications in bioforensics, biosurveillance, and for use in clinical settings. However, to make the most of these new data, new methodology needs to be developed that can accommodate large volumes of genetic data in a computationally efficient manner. We present a statistical framework to analyze raw next-generation sequence reads from purified or mixed environmental or targeted infected tissue samples for rapid species identification and strain attribution against a robust database of known biological agents. Our method, Pathoscope, capitalizes on a Bayesian statistical framework that accommodates information on sequence quality, mapping quality and provides posterior probabilities of matches to a known database of target genomes. Importantly, our approach also incorporates the possibility that multiple species can be present in the sample and considers cases when the sample species/strain is not in the reference database. Furthermore, our approach can accurately discriminate between very closely related strains of the same species with very little coverage of the genome and without the need for multiple alignment steps, extensive homology searches, or genome assembly- which are time consuming and labor intensive steps. We demonstrate the utility of our approach on genomic data from purified and in silico 'environmental' samples from known bacterial agents impacting human health for accuracy assessment and comparison with other approaches.
A 16S rRNA gene database (http://greengenes.lbl.gov) addresses limitations of public repositories by providing chimera screening, standard alignment, and taxonomic classification
using multiple published taxonomies. It was found that there is incongruent taxonomic nomenclature among curators even at
the phylum level. Putative chimeras were identified in 3% of environmental sequences and in 0.2% of records derived from isolates.
Environmental sequences were classified into 100 phylum-level lineages in the Archaea and Bacteria.
Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional
environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first
3 years of life. During this time, half of the twin pairs remained well nourished, whereas 43% became discordant, and 7% manifested
concordance for acute malnutrition. Both children in twin pairs discordant for kwashiorkor were treated with a peanut-based,
ready-to-use therapeutic food (RUTF). Time-series metagenomic studies revealed that RUTF produced a transient maturation of
metabolic functions in kwashiorkor gut microbiomes that regressed when administration of RUTF was stopped. Previously frozen
fecal communities from several discordant pairs were each transplanted into gnotobiotic mice. The combination of Malawian
diet and kwashiorkor microbiome produced marked weight loss in recipient mice, accompanied by perturbations in amino acid,
carbohydrate, and intermediary metabolism that were only transiently ameliorated with RUTF. These findings implicate the gut
microbiome as a causal factor in kwashiorkor.
Microbial exposures and sex hormones exert potent effects on autoimmune diseases, many of which are more prevalent in women.
We demonstrate that early-life microbial exposures determine sex hormone levels and modify progression to autoimmunity in
the nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D). Colonization by commensal microbes elevated serum testosterone
and protected NOD males from T1D. Transfer of gut microbiota from adult males to immature females altered the recipient's
microbiota, resulting in elevated testosterone and metabolomic changes, reduced islet inflammation and autoantibody production,
and robust T1D protection. These effects were dependent on androgen receptor activity. Thus, the commensal microbial community
alters sex hormone levels and regulates autoimmune disease fate in individuals with high genetic risk.
Symbiotic microorganisms that reside in the human intestine are adept at foraging glycans and polysaccharides, including those in dietary plants (starch, hemicellulose and pectin), animal-derived cartilage and tissue (glycosaminoglycans and N-linked glycans), and host mucus (O-linked glycans). Fluctuations in the abundance of dietary and endogenous glycans, combined with the immense chemical variation among these molecules, create a dynamic and heterogeneous environment in which gut microorganisms proliferate. In this Review, we describe how glycans shape the composition of the gut microbiota over various periods of time, the mechanisms by which individual microorganisms degrade these glycans, and potential opportunities to intentionally influence this ecosystem for better health and nutrition.
To understand the impact of gut microbes on human health and well-being it is crucial to assess their genetic potential. Here we describe the Illumina-based metagenomic sequencing, assembly and characterization of 3.3 million non-redundant microbial genes, derived from 576.7 gigabases of sequence, from faecal samples of 124 European individuals. The gene set, approximately 150 times larger than the human gene complement, contains an overwhelming majority of the prevalent (more frequent) microbial genes of the cohort and probably includes a large proportion of the prevalent human intestinal microbial genes. The genes are largely shared among individuals of the cohort. Over 99% of the genes are bacterial, indicating that the entire cohort harbours between 1,000 and 1,150 prevalent bacterial species and each individual at least 160 such species, which are also largely shared. We define and describe the minimal gut metagenome and the minimal gut bacterial genome in terms of functions present in all individuals and most bacteria, respectively.
Type 2 diabetes (T2D) is a result of complex gene-environment interactions, and several risk factors have been identified, including age, family history, diet, sedentary lifestyle and obesity. Statistical models that combine known risk factors for T2D can partly identify individuals at high risk of developing the disease. However, these studies have so far indicated that human genetics contributes little to the models, whereas socio-demographic and environmental factors have greater influence. Recent evidence suggests the importance of the gut microbiota as an environmental factor, and an altered gut microbiota has been linked to metabolic diseases including obesity, diabetes and cardiovascular disease. Here we use shotgun sequencing to characterize the faecal metagenome of 145 European women with normal, impaired or diabetic glucose control. We observe compositional and functional alterations in the metagenomes of women with T2D, and develop a mathematical model based on metagenomic profiles that identified T2D with high accuracy. We applied this model to women with impaired glucose tolerance, and show that it can identify women who have a diabetes-like metabolism. Furthermore, glucose control and medication were unlikely to have major confounding effects. We also applied our model to a recently described Chinese cohort and show that the discriminant metagenomic markers for T2D differ between the European and Chinese cohorts. Therefore, metagenomic predictive tools for T2D should be specific for the age and geographical location of the populations studied.
Dynamic protein binding to DNA elements regulates genome function and cell fate. Although methods for mapping in vivo protein-DNA interactions are becoming crucial for every aspect of genomic research, they are laborious and costly, thereby limiting progress. Here we present a protocol for mapping in vivo protein-DNA interactions using a high-throughput chromatin immunoprecipitation (HT-ChIP) approach. By using paramagnetic beads, we streamline the entire ChIP and indexed library construction process: sample transfer and loss is minimized and the need for manually labor-intensive procedures such as washes, gel extraction and DNA precipitation is eliminated. All of this allows for fully automated, cost effective and highly sensitive 96-well ChIP sequencing (ChIP-seq). Sample preparation takes 3 d from cultured cells to pooled libraries. Compared with previous methods, HT-ChIP is more suitable for large-scale in vivo studies, specifically those measuring the dynamics of a large number of different chromatin modifications/transcription factors or multiple perturbations.