Project description:Small intestinal bacterial overgrowth (SIBO) has been implicated in symptoms associated with functional gastrointestinal disorders (FGIDs), though mechanisms remain poorly defined and treatment involves non-specific antibiotics. Here we show that SIBO based on duodenal aspirate. culture reflects an overgrowth of anaerobes, does not correspond with patient symptoms, and may be a result of dietary preferences. Small intestinal microbial composition, on the other hand, is significantly altered in symptomatic patients and does not correspond with aspirate culture results. In a pilot interventional study we found that switching from a high fiber diet to a low fiber, high simple sugar diet triggered FGID-related symptoms and decreased small-intestinal microbial diversity and small-intestinal permeability. Our findings demonstrate that characterizing small intestinal microbiomes in patients with gastrointestinal symptoms may allow a more targeted antibacterial or a diet-based approach to treatment.
Project description:Objectives: Obstructive Sleep Apnea (OSA) is related to repeated upper airway collapse, intermittent hypoxia, and intestinal barrier dysfunction. The resulting damage to the intestinal barrier may affect or be affected by the intestinal microbiota. Methods: A prospective case-control was used, including 48 subjects from Sleep Medicine Center of Nanfang Hospital. Sleep apnea was diagnosed by overnight polysomnography. Fecal samples and blood samples were collected from subjects to detect intestinal microbiome composition (by 16S rDNA gene amplification and sequencing) and intestinal barrier biomarkers – intestinal fatty acid-binding protein (I-FABP) and D-lactic acid (D-LA) (by ELISA and colorimetry, respectively). Results: The severity of OSA was related to differences in the structure and composition of the intestinal microbiome. Enriched Fusobacterium, Megamonasa, Lachnospiraceae_UCG_006, and reduced Anaerostipes was found in patients with severe OSA. Enriched Ruminococcus_2, Lachnoclostridium, Lachnospiraceae_UCG_006, and Alloprevotella was found in patients with high intestinal barrier biomarkers. Lachnoclostridium and Lachnospiraceae_UCG_006 were the common dominant bacteria of OSA and intestinal barrier damage. Fusobacterium and Peptoclostridium was independently associated with apnea-hypopnea index (AHI). The dominant genera of severe OSA were also related to glucose, lipid, neutrophils, monocytes and BMI. Network analysis identified links between the intestinal microbiome, intestinal barrier biomarkers, and AHI. Conclusions: The study confirms that changes in the intestinal microbiota are related to intestinal barrier biomarkers among patients in OSA. These changes may play a pathophysiological role in the systemic inflammation and metabolic comorbidities associated with OSA, leading to multi-organ morbidity of OSA.
Project description:The goal of this study was to gain insights into the transcriptomes, mutations and copy number variants present in small intestinal neuroendocrine tumors. The present dataset contains RNA-sequencing performed on seven such tumors.
Project description:The intestinal microbiota has been identified as an environmental factor that markedly impacts energy storage and body fat accumulation, yet the underlying mechanisms remain unclear. Here we show that the microbiota regulates body composition through the circadian transcription factor NFIL3. Nfil3 transcription oscillates diurnally in intestinal epithelial cells and the amplitude of the circadian oscillation is controlled by the microbiota through type 3 innate lymphoid cells (ILC3), STAT3, and the epithelial cell circadian clock. NFIL3 controls expression of a circadian lipid metabolic program and regulates lipid absorption and export in intestinal epithelial cells. These findings provide mechanistic insight into how the intestinal microbiota regulates body composition and establish NFIL3 as an essential molecular link among the microbiota, the circadian clock, and host metabolism.
Project description:The gastric barrier plays a major role in the maintanance of the distal intestinal microbiome composition. It has been shown before that the use of gastric acid suppression medication, such as proton pump inhibitors, are associated with distinctive alterations of the intestinal microbiome. Foremost, the invasion of predominantly oral bacteria, like Veillonella and Streptococcus species, were a resurring finding in previous reports.
Gastric cancer treatment includes the total or subtotal resection of the stomach which can influence the gastric acid production. However, the influence by alterations in gastric milieu after this treatment on the composition of the intestinal microbiome is not well studied.
Therefore, the intestinal microbiome of patients after total or subtotal gastrectomy and its influence on intestinal inflammation and gut permeability will be studied.
Project description:Barrier epithelia are essential to organismal homeostasis, and changes in their cellular composition are observed in human diseases. Within the small intestine, adult stem cells establish tissue cellularity, and may provide a means to control the abundance and quality of specialized epithelial cells. Nevertheless, we lack suitable approaches to identify biological targets and small molecules to modulate them. Here, we develop an extendable framework utilizing a physiologically-inspired organoid model to identify unknown, druggable regulators of intestinal stem cell differentiation that translate to intended manipulations in vivo. Specifically, we miniaturize and adapt an organoid model of Paneth cell differentiation to enable multiplexed phenotypic screening on the scale of thousands of samples, and employ longitudinal single-cell RNA-sequencing to understand hit biology. Strikingly, we identify that inhibitors of the nuclear exporter XPO1 modulate stem cell fate commitment, significantly increasing the abundance of Paneth cells independent of known differentiation cues. Our framework elucidates small molecules which modulate tissue stem cell biology and their underlying targets without the need for a priori knowledge of in vivo pathway biology.
Project description:Small intestinal bacterial overgrowth (SIBO) has been implicated in symptoms associated with functional gastrointestinal disorders (FGIDs), though mechanisms remain poorly defined and treatment involves non-specific antibiotics. Here we show that SIBO based on duodenal aspirate culture reflects an overgrowth of anaerobes, does not correspond with patient symptoms, and may be a result of dietary preferences. Small intestinal microbial composition, on the other hand, is significantly altered in symptomatic patients and does not correspond with aspirate culture results. In a pilot interventional study we found that switching from a high fiber diet to a low fiber, high simple sugar diet triggered FGID-related symptoms and decreased small-intestinal microbial diversity and small-intestinal permeability. Our findings demonstrate that characterizing small intestinal microbiomes in patients with gastrointestinal symptoms may allow a more targeted antibacterial or a diet-based approach to treatment.