Search Results (561)

The enteroendocrine system of the gastrointestinal (GI) tract is the largest endocrine organ in the human body, playing a central role in the regulation of hunger, satiety, digestion, and energy homeostasis. Numerous factors—including dietary components, physical activity, and the gut microbiota—affect the secretion of GI hormones. This study aims to analyze how these factors modulate enteroendocrine function and influence systemic metabolic regulation. This review synthesizes the current scientific literature on the physiology and distribution of enteroendocrine cells and mechanisms of hormone secretion in response to macronutrients, physical activity, and microbial metabolites. Special attention is given to the interactions between gut-derived signals and central nervous system pathways involved in appetite control. Different GI hormones are secreted in specific regions of the digestive tract in response to meal composition and timing. Macronutrients, particularly during absorption, stimulate hormone release, while physical activity influences hormone concentrations, decreasing ghrelin and increasing GLP-1, PYY, and leptin levels. The gut microbiota, through fermentation and metabolite production (e.g., SCFAs and bile acids), modulates enteroendocrine activity. Species such as Akkermansia muciniphila are associated with improved gut barrier integrity and enhanced GLP-1 secretion. These combined effects contribute to appetite regulation and energy balance. Diet composition, physical activity, and gut microbiota are key modulators of gastrointestinal hormone secretion. Their interplay significantly affects appetite regulation and metabolic health. A better understanding of these relationships may support the development of personalized strategies for managing obesity and related disorders. Full article

Sensorimotor integration along the gastrointestinal (GI) tract is crucial for normal gut function yet remains poorly understood in the context of neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD). The genetic tractability of zebrafish allows investigators to generate molecularly defined models that provide a means of studying the functional circuits of digestion in vivo. Optical transparency during development allows for the use of optogenetics and calcium imaging to elucidate the mechanisms underlying GI-related symptoms associated with ASD. The array of commonly reported symptoms implicates altered sensorimotor integration at various points along the GI tract, from the pharynx to the anus. We will examine the reflex arcs that facilitate swallowing, nutrient-sensing, absorption, peristalsis, and evacuation. The high level of conservation of these processes across vertebrates also enables us to explore potential therapeutic avenues to mitigate GI distress in ASD and other NDDs. Full article

Short-chain fatty acids (SCFAs) are metabolites derived from the fermentation of dietary fibre by gut bacteria. SCFAs function as essential regulators of host-microbiome interactions by participating in numerous physiological and pathological processes within the gastrointestinal (GI) tract. In recent years, the depletion of SCFAs has been increasingly linked to the pathogenesis of GI diseases. In this review, we summarize the current understanding of the therapeutic mechanisms of SCFAs in GI diseases, including inflammatory bowel disease, irritable bowel syndrome, metabolic dysfunction-associated steatotic liver disease, and acute pancreatitis. We next highlight potential therapeutic approaches that increase the endogenous production of SCFAs, including prebiotics, probiotics, and fecal microbiota transplantation. We conclude that, although SCFAs are promising therapeutic agents, further research is necessary due to variability in treatment efficacy, inconsistent clinical outcomes, and a limited understanding of SCFAs’ mechanisms of action. Full article

Microneedle arrays (MNAs) are becoming increasingly popular due to their ease of use and effectiveness in drug delivery and diagnostic applications. Improvements in three-dimensional (3D) printing techniques have made it possible to fabricate MNAs with high precision, intricate designs, and customizable properties, expanding their potential in medical applications. While most studies have focused on transdermal applications, non-transdermal uses remain relatively underexplored. This review summarizes recent developments in 3D-printed MNAs intended for non-transdermal drug delivery and diagnostic purposes. It includes a literature review of studies published in the past ten years, organized by the target delivery site—such as the brain and central nervous system (CNS), oral cavity, eyes, gastrointestinal (GI) tract, and cardiovascular and reproductive systems, among other emerging areas. The findings show that 3D-printed MNAs are more adaptable than skin-based delivery, opening up exciting new possibilities for use in a variety of organs and systems. To guarantee the effective incorporation of polymeric non-transdermal MNAs into clinical practice, additional research is necessary to address current issues with materials, manufacturing processes, and regulatory approval. Full article

Introduction: Gastrointestinal (GI) cancers are associated with high morbidity and mortality. Surgical resection, the primary treatment, often induces immunosuppression and increases the risk of postoperative complications. Perioperative immunonutrition (IMN), comprising formulations enriched with omega-3 fatty acids, arginine, nucleotides, and antioxidants, has emerged as a potential strategy to improve surgical outcomes by reducing complications, enhancing immune function, and promoting recovery. Methods: A systematic search of PubMed, Scopus, and the Cochrane Library was conducted on 28 October 2024 in accordance with PRISMA guidelines. Systematic reviews and meta-analyses evaluating perioperative IMN versus standard care in adult patients undergoing GI cancer surgery were included in the search. The outcomes assessed included infectious and non-infectious complications, wound healing, hospital stay, and nutritional status. The study quality was evaluated using AMSTAR 2, and the meta-analysis was conducted using random-effects models to calculate the pooled effect sizes (risk ratios [RRs], odds ratios [ORs], mean differences [MDs]) with 95% confidence intervals (CIs). Results: Sixteen systematic reviews and meta-analyses, including a total of 41,072 patients, were included. IMN significantly reduced infectious complications (RR: 0.62, 95% CI: 0.55–0.70; I² = 63.0%), including urinary tract infections (RR: 0.74, 95% CI: 0.61–0.89; I² = 0.0%) and wound infections (OR: 0.64, 95% CI: 0.55–0.73; I² = 34.4%). Anastomotic leak rates were notably lower (RR: 0.68, 95% CI: 0.62–0.75; I² = 8.2%). While no significant reduction in pneumonia risk was observed, non-infectious complications decreased significantly (RR: 0.83, 95% CI: 0.75–0.92; I² = 30.6%). IMN also reduced the length of hospital stay by an average of 1.92 days (MD: −1.92, 95% CI: −2.36 to −1.48; I² = 73.5%). Conclusions: IMN provides significant benefits in GI cancer surgery, reducing complications and improving recovery. However, variability in protocols and populations highlight the need for standardization and further high-quality trials to optimize its application and to validate its efficacy in enhancing surgical care. Full article

Immunotherapy has emerged as a transformative approach in gastrointestinal (GI) cancers, addressing historically poor survival rates in advanced-stage disease. Immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 axis demonstrate remarkable efficacy in colorectal cancer with deficient mismatch repair (dMMR) or high microsatellite instability (MSI-H), exemplified by trials like NICHE-2 achieving exceptional pathological response rates. However, significant limitations persist, including resistance in some dMMR/MSI-H tumors, minimal efficacy in proficient mismatch repair (pMMR) tumors, and low overall response rates across most GI malignancies due to tumor heterogeneity and immune evasion mechanisms. Predictive biomarkers such as tumor mutational burden (TMB) and PD-L1 expression are crucial for optimizing patient selection, while hypermutated pMMR tumors with POLE mutations represent emerging therapeutic opportunities. In pancreatic adenocarcinoma, where survival remains dismal, combination strategies with chemotherapy and novel approaches like cancer vaccines show promise but lack transformative breakthroughs. Esophagogastric cancers benefit from ICIs combined with chemotherapy, particularly in MSI-H and HER2-positive tumors, while hepatocellular carcinoma has achieved significant progress with combinations like atezolizumab–bevacizumab and durvalumab–tremelimumab surpassing traditional therapies. Biliary tract cancers show modest improvements with durvalumab–chemotherapy combinations. Despite these advances, immunotherapy faces substantial challenges including immune-related adverse events, acquired resistance through cancer immunoediting, and the need for biomarker-driven approaches to overcome tumor microenvironment barriers. This review discusses key clinical trials, therapeutic progress, and emerging modalities including CAR T-cell therapies and combination strategies, emphasizing the critical need to address resistance mechanisms and refine precision medicine approaches to fully realize immunotherapy’s potential in GI malignancies. Full article

Bariatric surgery involves major changes in the anatomy and physiology of the gastrointestinal tract, which may alter oral drug bioavailability and efficacy. Phosphodiesterase-5 inhibitor (PDE5i) drugs are the first-line treatment of erectile dysfunction, a condition associated with a higher BMI. In this paper, we examine the PDE5i vardenafil for possible post-bariatric changes in solubility/dissolution and absorption. Vardenafil solubility was determined in vitro, as well as ex vivo using aspirated gastric contents from patients prior to vs. following bariatric procedures. Dissolution was tested in vitro under unoperated stomach vs. post-gastric sleeve/bypass conditions. Lastly, the gathered solubility/dissolution data were used to produce an in silico physiologically based pharmacokinetic (PBPK) model (GastroPlus^®), where gastric volume, pH, and transit time, as well as proximal GI bypass (when relevant) were all adjusted for, evaluating vardenafil dissolution, gastrointestinal compartmental absorption, and pharmacokinetics before vs. after different bariatric procedures. pH-dependent solubility was demonstrated for vardenafil with low (pH 7) vs. high solubility (pH 1–5), which was confirmed ex vivo. The impaired dissolution of all vardenafil doses under post-gastric bypass conditions was demonstrated, contrary to complete (100%) dissolution under pre-surgery and post-sleeve gastrectomy conditions. Compared to unoperated individuals, PBPK simulations revealed altered pharmacokinetics post-gastric bypass (but not after sleeve gastrectomy), with 30% lower peak plasma concentration (C_max) and 40% longer time to C_max (T_max). Complete absorption after gastric bypass is predicted for vardenafil, which is attributable to significant absorption from the large intestine. The biopharmaceutics and PBPK analysis indicate that vardenafil may be similarly effective after sleeve gastrectomy as before the procedure. However, results after gastric bypass question the effectiveness of this PDE5i. Specifically, vardenafil’s onset of action might be delayed and unpredictable, negatively affecting the practicality of the intended use. Full article

The gastrointestinal (GI) tract is a major barrier against pathogens, including viruses. The antiviral responses in the GI epithelium have been broadly investigated, but data on the contribution of the stromal cells remain scarce. Melatonin, widely used to treat insomnia, has recently been proposed as an antiviral agent, yet its effect in the GI tract remains poorly understood. We compared the antiviral responses in Caco-2 monocultures and co-cultures with intestinal fibroblasts (HSIFs) and endothelial cells (HUVECs) after stimulation using Poly I:C. We evaluated the apoptosis, proliferation, key antiviral markers (IRF1, IRF3, IFNs, TBK1, STAT3), and mitochondrial and peroxisomal activation with and without melatonin. The Caco-2 cells cultured with the HSIFs and HUVECs demonstrated enhanced proliferation and reduced Poly I:C-induced apoptosis. The co-culture exhibited a more rapid IRF3-IFNλ1 response, higher TBK1 expression, and enhanced peroxisomal activation compared to these properties in the monoculture. Melatonin further reduced apoptosis and modulated organelle-specific antiviral signaling by suppressing peroxisomal activation and promoting mitochondrial activity. Reduced peroxisomal activation was associated with decreased TBK1, IRF3, and IFNλ1 levels and altered STAT3 signaling. These effects were more pronounced when melatonin was applied post-stimulation compared to that under prophylactic use. Fibroblast–endothelial interactions amplify the antiviral responses in the intestinal epithelial cells by activating the TBK1–IRF3–IFNλ1 axis. Melatonin modulates these responses, highlighting its therapeutic potential in viral GI infections. Full article

Obesity is a global health crisis with profound implications for cancer risk, particularly within the gastrointestinal (GI) tract. Mounting evidence demonstrates that excess adiposity contributes to the initiation, progression, and poor outcomes of GI malignancies through a constellation of interrelated mechanisms. This review comprehensively examines the biologic pathways linking obesity to cancers of the esophagus, stomach, colon, liver, pancreas, and gallbladder. Chronic low-grade inflammation, driven by adipose tissue-derived cytokines and immune cell infiltration, plays a central role in tumorigenesis via the activation of NF-κB, STAT3, and other pro-oncogenic signaling cascades. Hyperinsulinemia and insulin resistance increase mitogenic IGF-1 signaling, while dysregulated adipokines, particularly elevated leptin and reduced adiponectin, promote cellular proliferation and impair tumor suppression. Dysbiosis of the gut microbiome and alterations in bile acid metabolism generate carcinogenic metabolites that contribute to DNA damage and immune evasion. Additionally, obesity-induced tissue hypoxia fosters tumor growth through HIF-1α-mediated pathways. We further highlight organ-specific associations, such as visceral adiposity’s role in Barrett’s esophagus and hepatocellular carcinoma emerging from metabolic dysfunction-associated steatotic liver disease (MASLD). Importantly, emerging data suggest that weight loss, achieved via lifestyle, pharmacologic, or surgical interventions, may mitigate these carcinogenic pathways and improve tumor biology. As obesity prevalence continues to rise globally, elucidating its mechanistic ties to GI malignancies is essential for risk stratification, prevention strategies, and personalized care. By integrating epidemiologic and molecular insights, this review underscores the need for multidisciplinary approaches to curb the oncogenic burden of obesity and improve outcomes in GI oncology. Full article

Ionizing radiation (IR) poses a dual challenge in medicine; while essential for cancer therapy, it inflicts collateral damage to normal tissues, particularly the gastrointestinal (GI) tract. High-dose IR triggers acute radiation syndrome (ARS), characterized by crypt stem cell depletion, mucosal barrier disruption, inflammation, and potential progression to fibrosis and secondary malignancy. Emerging evidence identifies the epithelial kinase doublecortin-like kinase 1 (DCLK1)—highly expressed in GI tuft cells and cancer stem-like cells—as a master regulator of post-IR responses. DCLK1 integrates DNA repair (via p53/ATM), and survival signaling (via NF-κB, TGF-β, and MAPK) to promote epithelial regeneration, yet these same mechanisms contribute to therapy resistance and oncogenesis. DCLK1 further modulates the immune microenvironment by skewing macrophages toward an immunosuppressive M2 phenotype, enhancing tissue remodeling, angiogenesis, and immune evasion. Preclinical studies demonstrate that DCLK1 inhibition sensitizes tumors to radiotherapy while preserving mucosal repair. Therapeutic strategies targeting DCLK1, alongside radioprotective agents, immunomodulators, and senolytics, may enhance regeneration, limit fibrosis, and eradicate therapy-resistant cancer stem cells. This review highlights DCLK1’s dual role in regeneration and tumorigenesis and evaluates its potential as a therapeutic target and biomarker in IR-induced GI damage. Full article

Probiotics are often advised to be taken separately from antibiotics due to their sensitivity to antibiotic activity and gastrointestinal (GI) stress. However, Clostridium butyricum spores, as next-generation probiotics, may withstand concurrent use with antibiotics due to their unique structural adaptations. This study systematically evaluated the survival rates and morphological changes of C. butyricum spores exposed to 10 clinically relevant antibiotics in simulated gastric/intestinal fluids, exploring their feasibility for co-administration with antibiotics. Survival rates of C. butyricum spores were tested against 10 antibiotics across four classes (β-lactams, macrolides, aminoglycosides, and tetracyclines) in simulated GI fluids. Time–kill curves analyzed spore survival over 0–4 h, while scanning electron microscopy (SEM) observed spore wall integrity and morphological changes under different conditions. The spore survival rates remained >89% in intestinal fluid and >60% in gastric fluid across all antibiotics. SEM revealed gastric acid and proteolysis increased spore wall fragmentation, reducing resistance, whereas the intestinal environment preserved spore integrity. This study was the first to demonstrate that C. butyricum spores can survive simultaneous exposure to antibiotics in the gastrointestinal tract, challenging traditional probiotic usage guidelines. The findings support their co-administration with antibiotics to simplify dosing regimens and improve medication adherence. Such an approach advances antimicrobial stewardship by optimizing therapeutic strategies for antibiotic–probiotic combinations. Full article

The gastrointestinal (GI) tract is under neural, endocrine and paracrine control. The release (basal and in the presence of either cholinergic and opioid antagonists) of Met-enkephalin, insulin-like growth factor 1 (IGF-1) and somatostatin (SRIF) was determined quantitatively in vitro using explants of the crop, proventriculus and duodenum from either day 0 or day 1 chicks. In addition, the effects of cholinergic and opioid antagonists on PENK gene expression were examined. Thus, the aim of this study was to determine the roles of cholinergic and opioid receptors in the GI tract in newly hatched chickens. Moreover, the effect of IGF-1 and Met-enkephalin on cell division in duodenal explants in vitro was determined. There was both the release of Met-enkephalin from, and PENK expression in, the explants of the crop, proventriculus and duodenum tissue. This is the first report of any neuropeptide(s) being synthesized in and/or released from the crop. In vitro release of Met-enkephalin, IGF-1 and SRIF from duodenal and proventriculus explants was influenced (p < 0.01) by either cholinergic or opioid antagonists; for instance, in the presence of atropine, decreases (p < 0.001) of 17.8% and 57.7% are seen, respectively, in Met-enkephalin release and PENK expression in crop explants from day 1 chicks. Moreover, in the presence of atropine, there were increases (p < 0.001) of 47.7% and 70.9% in IGF-1 release in proventriculus explants from, respectively, day 0 and day 1 chicks. Met-enkephalin and/or IGF-1 stimulated the cell division of duodenal explants in vitro. This is the first report of Met-enkephalin release and PENK expression in the avian crop and of the effects of cholinergic or opioid antagonists on these factors. It is also the first report of either cholinergic or opioid control of IGF-1 release in the periphery of any species. There were strong relationships (p < 0.05) between the release of Met-enkephalin and that of IGF-1 in the duodenum and between the release of SRIF and that of IGF-1 in the proventriculus. This is the first report of IGF-1 and Met-enkephalin stimulating (p < 0.001) the proliferation of duodenal cells and, together, exerting a synergist effect. It is concluded that the release of Met-enkephalin, IGF-1 and SRIF from foregut regions is under tonic cholinergic and opioid control. Full article

Capsule endoscopy (CE) has revolutionized gastrointestinal (GI) diagnostics by providing a non-invasive, patient-centered approach to observing the digestive tract. Conceived in 2000 by Gavriel Iddan, CE employs a diminutive, ingestible capsule containing a high-resolution camera, LED lighting, and a power supply. It specializes in visualizing the small intestine, a region frequently unreachable by conventional endoscopy. CE helps detect and monitor disorders, such as unexplained gastrointestinal bleeding, Crohn’s disease, and cancer, while presenting a lower procedural risk than conventional endoscopy. Contrary to conventional techniques that necessitate anesthesia, CE reduces patient discomfort and complications. Nonetheless, its constraints, specifically the incapacity to conduct biopsies or therapeutic procedures, have spurred technical advancements. Five primary types of capsule endoscopes have emerged: steerable, magnetic, robotic, tethered, and hybrid. Their performance varies substantially. For example, the image sizes vary from 256 × 256 to 640 × 480 pixels, the fields of view (FOV) range from 140° to 360°, the battery life is between 8 and 15 h, and the frame rates fluctuate from 2 to 35 frames per second, contingent upon motion-adaptive capture. This study addresses a significant gap by methodically evaluating CE platforms, outlining their clinical preparedness, and examining the underexploited potential of artificial intelligence in improving diagnostic precision. Through the examination of technical requirements and clinical integration, we highlight the progress made in overcoming existing CE constraints and outline prospective developments for next-generation GI diagnostics. Full article

Faecal microbiota transplantation (FMT) has emerged as a transformative therapy in human medicine, particularly for managing recurrent Clostridioides difficile infections and other gastrointestinal (GI) disorders. Beyond the GI tract, FMT has shown potential in addressing extraintestinal conditions in people, including metabolic, immune-mediated, dermatological, neurological, and infectious diseases. Research in people has highlighted its efficacy in decolonising multidrug-resistant organisms in infection, mitigating autoimmune diseases, and improving outcomes in metabolic disorders such as obesity and diabetes. Furthermore, FMT has also been linked to enhanced responses to immunotherapy in cancer and improved management of hepatic and renal conditions. These findings underscore the intricate connections between the gut microbiome and systemic health, opening novel therapeutic avenues. In veterinary medicine, while FMT has demonstrated benefits for GI disorders, its application in extraintestinal diseases remains largely unexplored. Emerging evidence suggests that conditions such as atopic dermatitis, chronic kidney disease, immune-mediated diseases, and behavioural disorders in companion animals could benefit from microbiome-targeted therapies. However, significant gaps in knowledge persist, particularly regarding the long-term safety and efficacy for veterinary applications. This review synthesises findings from human medicine to assess their relevance for veterinary applications and future research. Full article

In poultry production, antibiotics have been excessively used as growth promoters to support well-being and decrease mortality caused by pathogenic microorganisms. The overuse of antibiotics has led to the emergence of antibiotic-resistant bacteria and the presence of antibiotic residues in poultry products. To counteract this problem, probiotics could be used as adjuncts or as substitutes for preserving a diverse and balanced microflora to prevent the colonization and multiplication of pathogenic bacteria in the GI tract. This study aimed to isolate and characterize the potential probiotic properties of lactic acid bacteria from the small intestine of 23-week-old broiler breeders, with the goal of identifying potential probiotic candidates. Four phenotypically healthy broiler breeders were selected, and intestinal contents were aseptically collected and cultured on MRS agar. From the initial pool of 39 colonies, six isolates were identified based on Gram-positive and catalase-negative characteristics and further classified using 16S rRNA sequencing as Levilactobacillus brevis (n = 3), Pediococcus pentosaceus (n = 2), and Streptococcus salivarius (n = 1). These strains were further evaluated for probiotic properties such as transit resistance to simulated upper gastrointestinal conditions, antagonist activity, haemolytic activity, and cell surface properties such as autoaggregation, co-aggregation and hydrophobicity, in vitro. L. brevis NKFS8 showed good tolerance to pH 3, while P. pentosaceus NKSF10 exhibited good tolerance to pH 4 acidic conditions. All isolates demonstrated good survivability in bile salt concentration of 3% (w/v), with P. pentosaceus NKSF10 exhibiting the highest tolerance. The isolates showed a wide range of antagonistic activity against the test pathogens Pseudomonas aeruginosa (ATCC 27853), Salmonella typhimurium, Salmonella enterica (ATCC 13314), Staphylococcus aureus (ATCC 29213), and Listeria monocytogenes (ATCC 7644). Furthermore, these strains exhibited good auto-aggregation, co-aggregation, and hydrophobicity properties. In conclusion, lactic acid bacteria from the small intestine of broiler breeders present a valuable prospect for the development of effective probiotics. These probiotics can be utilized as a supplementary inclusion in poultry feed, obviating the need for antibiotics as growth promoters. Nevertheless, additional in vivo studies are required to closely monitor and assess the effects of probiotics on the gastrointestinal system of chickens. Full article