Bariatric surgery is the most effective treatment for obesity and its comorbidities, but mechanisms of bariatric surgery remain unknown. In addition to volume restriction and malabsorption, gut hormones, bile acids, adipokines, intestinal microbiome and central nervous system may be the potential mechanisms.
Bariatric Surgery ; Gastrointestinal Hormones ; Humans ; Intestines ; microbiology ; Microbiota ; Obesity

OBJECTIVE: To investigate the characterization of the salivary microbiome in people with obesity and the differences in microbial composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight controls. METHODS: The study was carried out in people with obesity and age- and sex-matched normal weight controls. None of these selected participants had the systemic disease, oral mucosal disease or periodontal disease. Unstimulated saliva samples were collected and oral examination was conducted. DNAs from saliva samples were extracted and sequenced in an Illumina NextSeq 500 platform. Community composition, linear discriminant analysis of taxonomic differences,gene prediction, gene set construction and annotation of gene function were performed. RESULTS: The classified bacterial reads of the samples were 2 630 428 for each sample. A total of 11 phyla, 19 classes, 26 orders, 41 families, 62 genera and 164 species were detected ultimately. All samples had the same predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria and Fusobacteria). There were statistical differences between the groups at the class, order, family, genus and species levels. At the class level, Negativicutes and Erysipelotrichia were more abundant in the obesity group, while Flavobacteriia and Bateroidetes dominated in normal weight group (P<0.05). At the species level, 16 showed significant differences in relative abundance among the groups, in which Prevotella melaninogenica,Prevotella salivae,Solobacterium moorei and Atopobium parvulum ware more abundant in the obesity group, whereas Streptococcus sanguinis dominated in normal weight group (P<0.05). The people with obesity had a higher number of salivary microbial genes (P<0.05). We produced statistics on gene prediction and found salivary microbiome of obesity group had a higher number of genes (P < 0.05). Genes associated with the pathways of metabolism and environmental information processing and human diseases were significantly enriched in the saliva samples of people with obesity (P < 0.01). CONCLUSION Significant differences were seen in composition, gene function and metabolic pathways of salivary microbiome between people with obesity and normal weight people. We hope to go on further study with larger sample size in the near future.
Bacteria/isolation & purification* ; Female ; Humans ; Male ; Microbiota ; Obesity/microbiology* ; Pilot Projects ; RNA, Ribosomal, 16S ; Saliva/microbiology*

Animals ; Gastrointestinal Microbiome ; Gastrointestinal Tract ; microbiology ; Humans ; Obesity ; microbiology ; pathology ; therapy

The human body is actually a super-organism that is composed of 10 times more microbial cells than our body cells. Metagenomic study of the human microbiome has demonstrated that there are 3.3 million unique genes in human gut, 150 times more genes than our own genome, and the bacterial diversity analysis showed that about 1000 bacterial species are living in our gut and a majority of them belongs to the divisions of Firmicutes and Bacteriodetes. In addition, most people share a core microbiota that comprises 50-100 bacterial species when the frequency of abundance at phylotype level is not considered, and a core microbiome harboring more than 6000 functional gene groups is present in the majority of human gut surveyed till now. Gut bacteria are not only critical for regulating gut metabolism, but also important for host immune system as revealed by animal studies.
Animals ; Biota ; Cell Culture Techniques ; Digestive System ; immunology ; microbiology ; Digestive System Diseases ; microbiology ; Humans ; Immune System ; Metagenome ; Obesity ; microbiology ; Symbiosis

Human gut microbiota plays a key role in the development of obesity. Intestinal flora can regulate energy absorption and nutrition metabolism, increasing the energy harvesting from diet. Alteration of gut flora produces excessive lipopolysaccharide, which, when absorbed into the blood, can induce inflammatory reactions and promote the high-fat diet-associated obesity and metabolic syndrome. Intestinal flora increase visceral fat deposition by lowering the expression of Fiaf in intestinal mucosa. Different immune status also affects the intestinal flora.The gut microbiota is hypothesized to be an environmental factor that contributes to obesity; by interacting with factors such as host and diet, it adjusts the energy metabolism. Antibiotics or probiotics may alter the composition of intestinal microflora and improve the metabolic syndrome, and thus provides new treatment options.
Animals ; Diet, High-Fat ; Gastrointestinal Tract ; microbiology ; Humans ; Inflammation ; etiology ; Mice ; Obesity ; microbiology ; therapy ; Probiotics ; therapeutic use

Advances in sequencing technology and the development of metagenomics have opened up new ways to investigate the microorganisms inhabiting the human gut. The intestinal microbiota confer protection against pathogens, contribute to the maturation of the immune system, and regulate host metabolism. The composition of gut microbiota in early life is influenced by mode of birth, diet, and antibiotics. Decreased biodiversity and alterations in the composition of the intestinal microbiota have been observed in many diseases including obesity, neonatal necrotizing enterocolitis, inflammatory bowel disease, and recurrent Clostridium difficile infection. Therapeutic options for the diseases linked to imbalance in the microbiota include modifying the gut microbiota through diet, probiotics, and fecal transplants.
Animals ; Anti-Bacterial Agents/therapeutic use ; Clostridium difficile/isolation & purification/pathogenicity ; Enterocolitis, Pseudomembranous/drug therapy/microbiology/pathology ; Fatty Liver/etiology/microbiology ; Humans ; Inflammatory Bowel Diseases/etiology/microbiology ; Intestines/*microbiology ; *Microbiota ; Obesity/etiology/microbiology

OBJECTIVETo investigate the effect of intermittent fasting on metabolize and gut microbiota in obese presenium rats fed with high-fat-sugar-diet.

METHODSWe fed the Wistar rats with high-fat and high-sugar diet to induce adiposity, and the rats for intermittent fasting were selected base on their body weight. The rats were subjected to fasting for 72 h every 2 weeks for 18 weeks. OGTT test was performed and fasting blood samples and fecal samples were collected for measurement of TC, TG, HDL-C and LDL-C and sequence analysis of fecal 16S rRNA V4 tags using Illumina. Gut microbial community structure was analyzed with QIIME and LEfSe.

RESULTSAfter the intervention, the body weight of the fasting rats was significantly lower than that in high-fat diet group (P<0.01). OGTT results suggested impairment of sugar tolerance in the fasting group, which showed a significantly larger AUC than compared with the high-fat diet group (P<0.05). Intermittent fasting significantly reduced blood HDL-C and LDL-C levels (P<0.05) and partially restored liver steatosis, and improved the gut microbiota by increasing the abundance of YS2, RF32 and Helicobacteraceae and reducing Lactobacillus, Roseburia, Erysipelotrichaceae and Ralstonia. Bradyrhizobiaceae was found to be positively correlated with CHOL and HDL-C, and RF39 was inversely correlated with the weight of the rats.

CONCLUSIONIntermittent fasting can decrease the body weight and blood lipid levels and restore normal gut microbiota but can cause impairment of glucose metabolism in obese presenium rats.

Animals ; Body Weight ; Diet, High-Fat ; Fasting ; Fatty Liver ; microbiology ; physiopathology ; Gastrointestinal Microbiome ; Lipids ; blood ; Obesity ; microbiology ; physiopathology ; RNA, Ribosomal, 16S ; Rats ; Rats, Wistar

Animals ; Bacterial Translocation ; Fecal Microbiota Transplantation ; Gastrointestinal Microbiome ; Humans ; Insulin Resistance ; Obesity ; microbiology ; therapy ; Probiotics ; therapeutic use

Animal gastrointestinal tract contains a complex community of microbes, whose composition ultimately reflects the co-evolution of microorganisms with their animal host. The gut microbial community of humans and animals has received significant attention from researchers because of its association with health and disease. The application of metagenomics technology enables researchers to study not only the microbial composition but also the function of microbes in the gastrointestinal tract. In this paper, combined with our own findings, we summarized advances in studying gastrointestinal tract microorganism with metagenomics and the bioinformatics technology.
Animals ; Gastrointestinal Tract ; microbiology ; Humans ; Hyperglycemia ; etiology ; Inflammatory Bowel Diseases ; etiology ; Metagenome ; physiology ; Metagenomics ; methods ; Obesity ; etiology

In recent years, more and more studies have noted the close association between gut microbiota and the development and progression of obesity. Gut microbiota may act on obesity by increasing energy intake, affecting the secretion of intestinal hormones, inducing chronic systemic inflammation, and producing insulin resistance. This article reviews the association between childhood obesity and gut microbiota, as well as possible mechanisms, in an attempt to provide a reference for the etiology, prevention and treatment of childhood obesity.
Animals ; Energy Metabolism ; Gastrointestinal Microbiome ; Glucagon-Like Peptide 2 ; physiology ; Humans ; Insulin Resistance ; Obesity ; etiology ; microbiology ; prevention & control