The structure of intestinal tissue is complex. In vitro simulation of intestinal structure and function is important for studying intestinal development and diseases. Recently, organoids have been successfully constructed and they have come to play an important role in biomedical research. Organoids are miniaturized three-dimensional (3D) organs, derived from stem cells, which mimic the structure, cell types, and physiological functions of an organ, making them robust models for biomedical research. Intestinal organoids are 3D micro-organs derived from intestinal stem cells or pluripotent stem cells that can successfully simulate the complex structure and function of the intestine, thereby providing a valuable platform for intestinal development and disease research. In this article, we review the latest progress in the construction and application of intestinal organoids.
Organoids/cytology* ; Intestines/physiology* ; Humans ; Animals ; Pluripotent Stem Cells

The gut microbiota is an indispensable symbiotic entity within the human holobiont, serving as a critical regulator of host lipid metabolism homeostasis. Therefore, it has emerged as a central subject of research in the pathophysiology of metabolic disorders. This microbial consortium orchestrates key aspects of host lipid dynamics-including absorption, metabolism, and storage-through multifaceted mechanisms such as the enzymatic processing of dietary polysaccharides, the facilitation of long-chain fatty acid uptake by intestinal epithelial cells (IECs), and the bidirectional modulation of adipose tissue functionality. Mounting evidence underscores that gut microbiota-derived metabolites not only directly mediate canonical lipid metabolic pathways but also interface with host immune pathways, epigenetic machinery, and circadian regulatory systems, thereby establishing an intricate crosstalk that coordinates systemic metabolic outputs. Perturbations in microbial composition (dysbiosis) drive pathological disruptions to lipid homeostasis, serving as a pathogenic driver for conditions such as obesity, hyperlipidemia, and non-alcoholic fatty liver disease (NAFLD). This review systematically examines the emerging mechanistic insights into the gut microbiota-mediated regulation of intestinal lipid metabolism, while it elucidates its translational implications for understanding metabolic disease pathogenesis and developing targeted therapies.
Humans ; Gastrointestinal Microbiome/physiology* ; Lipid Metabolism ; Animals ; Intestinal Mucosa/metabolism* ; Homeostasis ; Dysbiosis ; Obesity/metabolism* ; Intestines/microbiology* ; Non-alcoholic Fatty Liver Disease/metabolism* ; Metabolic Diseases/metabolism*

In order to seek a patient friendly and low-cost intestinal examination method, a structurally simple pneumatic soft intestinal robot inspired by inchworms is designed and manufactured. The intestinal robot was consisted of two radially expanding cylindrical rubber film airbags for anchoring and one low density polyethylene film airbag for axial elongation, which achieved movement in the intestine by mimicking the crawling of inchworms. Theoretical derivation was conducted on the relationship between the internal air pressure of the anchored airbag and the free deformation size after expansion, and it pointed out that the uneven deformation of the airbag was a phenomenon of expansion instability caused by large deformation of the rubber material. The motion performance of the intestinal robot was validated in different sizes of hard tubes and ex vivo pig small intestine. The running speed in the ex vivo pig small intestine was 4.87 mm/s, with an anchoring force of 2.33 N when stationary, and could smoothly pass through a 90 ° bend. This work expects to provide patients with a new method of low pain and low-cost intestinal examination.
Animals ; Swine ; Robotics/instrumentation* ; Equipment Design ; Intestine, Small/physiology* ; Intestines/physiology* ; Humans

There are direct and indirect interactions between gut microbiota and host immune response, which can have a multifaceted impact on host health. Dysbiosis caused by disturbances in the gut microbiota is associated with susceptibility to many diseases, especially immune-related diseases. Based on the research results in recent years, this paper introduced the mechanism of the interaction between gut microbiota and host immunity, and expounded the role of gut microbiota in the occurrence and development of immune-related diseases, including intestinal system diseases such as inflammatory bowel disease and other systemic diseases such as rheumatoid arthritis, and summarized disease treatment strategies targeting gut microbiota. A better understanding of the research progress of gut microbiota and immune-related diseases will help us in the prevention and management of such diseases, and broaden our path to discover disease intervention targets.
Gastrointestinal Microbiome/physiology* ; Humans ; Inflammatory Bowel Diseases ; Intestines

Intestinal failure (IF) is defined as the critical reduction of functional intestines below the minimum needed to absorb nutrients and fluids, so that intravenous supplementation with parenteral nutrition (PN) is required to maintain health and/or growth. Although the benefits are evident, patients receiving PN can suffer from serious cholestasis due to lack of enteral feeding and small intestinal bacterial overgrowth (SIBO). One such complication that may arise is intestinal failure-associated liver disease (IFALD). Evidences from recent studies suggest that alterations in the intestinal microbiota, as well as intraluminal bile acid driven signaling, may play a critical role in both hepatic and intestinal injury. Since Marshall first proposed the concept of the gut-liver axis in 1998, the role of gut-liver axis disorders in the development of IFALD has received considerable attention. The conversation between gut and liver is the key to maintain liver metabolism and intestinal homeostasis, which influences each other and is reciprocal causation. However, as a "forgotten organ" , intestinal microbiota on the pathogenesis of IFALD has not been well reflected. As such, we propose, for the first time, the concept of gut-microbiota-liver axis to emphasize the importance of intestinal microbiota in the interaction of gut-liver axis. Analysis and research on gut-microbiota-liver axis will be of great significance for understanding the pathogenesis of IFALD and improving the prevention and treatment measures.
Bacterial Infections/physiopathology* ; Bile Acids and Salts/physiology* ; Cholestasis/physiopathology* ; Enteral Nutrition ; Gastrointestinal Microbiome/physiology* ; Humans ; Intestinal Diseases/physiopathology* ; Intestines/physiopathology* ; Liver/physiopathology* ; Liver Diseases/physiopathology* ; Parenteral Nutrition/adverse effects* ; Short Bowel Syndrome/physiopathology* ; Signal Transduction

BackgroundIncreasing evidence has supported the link of intestinal Fusobacterium nucleatum infection to colorectal cancer (CRC). However, the value of F. nucleatum as a biomarker in CRC detection has not been fully defined. In order to reduce the random error and bias of individual research, this meta-analysis aimed to evaluate the diagnostic performance of intestinal F. nucleatum in CRC patients and provide evidence-based data to clinical practice.

MethodsAn article search was performed from PubMed, Embase, Cochrane Library, and Web of Science databases up to December 2017, using the following key words: "Fusobacterium nucleatum", "Fusobacterium spp.", "Fn", "colorectal cancer(s)", "colorectal carcinoma(s)", "colorectal neoplasm(s)", and "colorectal tumor(s)". Articles on relationships between F. nucleatum and CRC were selected according to the preestablished inclusion and exclusion criteria. This meta-analysis was performed using STATA 12.0 software, which included mapping of forest plots, heterogeneity tests, meta-regression, subgroup analysis, sensitivity analysis, and publication bias. The sensitivity, specificity, positive likelihood ratio (LR), negative LR, diagnostic odds ratio (DOR), and their corresponding 95% confidence interval (CI) of each eligible study were summarized.

ResultsFinally, data for 1198 participants (629 CRC and 569 healthy controls) in 10 controlled studies from seven articles were included. The summary receiver operator characteristic curve was mapped. The diagnostic performance of intestinal F. nucleatum infection on CRC was as follows: the area under the curve: 0.86 (95% CI: 0.83-0.89), the pooled sensitivity: 0.81 (95% CI: 0.64-0.91), specificity: 0.77 (95% CI: 0.59-0.89), and DOR: 14.00 (95% CI: 9.00-22.00).

ConclusionIntestinal F. nucleatum is a valuable marker for CRC diagnosis.

Colonic Neoplasms ; microbiology ; Colorectal Neoplasms ; microbiology ; Fusobacterium nucleatum ; physiology ; Humans ; Intestines ; microbiology ; pathology

Complex communities of microorganisms, termed commensal microbiota, inhabit mucosal surfaces and profoundly influence host physiology as well as occurrence of allergic diseases. Perturbing factors such as the mode of delivery, dietary fibers and antibiotics can influence allergic diseases by altering commensal microbiota in affected tissues as well as in intestine. Here, we review current findings on the relationship between commensal microbiota and allergic diseases, and discuss the underlying mechanisms that contribute to the regulation of allergic responses by commensal microbiota.
Anti-Bacterial Agents ; Asthma ; Dermatitis, Atopic ; Dietary Fiber ; Food Hypersensitivity ; Hygiene* ; Intestines ; Microbiota* ; Physiology

Incretin hormones are produced by enteroendocrine cells (EECs) in the intestine in response to ingested nutrient stimuli. The incretin effect is defined as the difference in the insulin secretory response between the oral glucose tolerance test and an isoglycemic intravenous glucose infusion study. The pathophysiology of the decreased incretin effect has been studied as decreased incretin sensitivity and/or β-cell dysfunction per se. Interestingly, robust increases in endogenous incretin secretion have been observed in many types of metabolic/bariatric surgery. Therefore, metabolic/bariatric surgery has been extensively studied for incretin physiology, not only the hormones themselves but also alterations in EECs distribution and genetic expression levels of gut hormones. These efforts have given us an enormous understanding of incretin biology from synthesis to in vivo behavior. Further innovative studies are needed to determine the mechanisms and targets of incretin hormones.
Bariatric Surgery ; Biology ; Enteroendocrine Cells ; European Union ; Glucose ; Glucose Tolerance Test ; Incretins* ; Insulin ; Intestines* ; Physiology

Irritable bowel syndrome (IBS) is a multifactorial functional disorder with no clearly defined etiology or pathophysiology. Modern culture-independent techniques have improved the understanding of the gut microbiota's composition and demonstrated that an altered gut microbiota profile might be found in at least some subgroups of IBS patients. Research on IBS from a microbial perspective is gaining momentum and advancing. This review will therefore highlight potential links between the gut microbiota and IBS by discussing the current knowledge of the gut microbiota; it will also illustrate bacterial-host interactions and how alterations to these interactions could exacerbate, induce or even help alleviate IBS.
Gastrointestinal Microbiome/*physiology ; Humans ; Intestines/*microbiology ; Irritable Bowel Syndrome/*microbiology/therapy

Proteases play important roles in parasite development and host parasite interactions. The protease of Kudoa spp. has been recognized as a key factor of severe proteolysis of fish muscle post-mortem; however, there is little information available regarding the protease of Kudoa (K.) septempunctata, which was recently identified as a cause of food poisoning in humans. The present study was conducted to isolate and characterize proteases to elucidate the type of protease contained in the parasite and determine the optimal pH for protease activity. We confirmed the cysteine protease and metalloprotease produced by K. septempunctata. While the cysteine protease showed optimal activity at pH 5 that decreased rapidly with increasing pH, the optimal activity of metalloprotease was pH 7, and it remained stable from pH 6 to pH 8. These results indicate that the pH of cysteine protease is not proper for fish muscle postmortem, and that metalloprotease can act in human intestines. Overall, the present study provides important information that improves our understanding of the role of protease physiology and the subsequent food poisoning caused by K. septempunctata.
Cysteine Proteases ; Foodborne Diseases ; Host-Parasite Interactions ; Humans ; Hydrogen-Ion Concentration ; Intestines ; Parasites ; Peptide Hydrolases* ; Physiology ; Proteolysis