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    4767 results match your criteria American Journal of Physiology - Gastrointestinal and Liver Physiology [Journal]

    1 OF 96

    Neuro-immune interaction and the regulation of intestinal immune homeostasis.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 14:ajpgi.00425.2016. Epub 2017 Sep 14.
    KU Leuven.
    Many essential gastrointestinal functions, including motility, secretion and blood flow are regulated by the autonomic nervous system (ANS), both through intrinsic enteric neurons and extrinsic (sympathetic and parasympathetic) innervation. Recently identified neuro-immune mechanisms, in particular the interplay between enteric neurons and muscularis macrophages, are now considered to be essential for fine-tuning peristalsis. These findings shed new light on how intestinal immune cells can support enteric nervous function. Read More

    Role of MicroRNA-423-5p in post-transcriptional regulation of the intestinal riboflavin transporter-3.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 14:ajpgi.00238.2017. Epub 2017 Sep 14.
    UCI/VA Medical Center
    Riboflavin (RF) is essential for normal cellular functions and health. Humans obtain RF from exogenous sources via intestinal absorption that involves a highly specific carrier-mediated process. We have recently established that the riboflavin transporter-3 (RFVT3) is vital for the normal intestinal RF uptake process, and have characterized certain aspects of its transcriptional regulation. Read More

    Hepatocyte Nuclear Factor 4α Regulates the Expression of Intestinal Epithelial Na(+)/H(+) Exchanger Isoform-3 (NHE3).
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 7:ajpgi.00225.2017. Epub 2017 Sep 7.
    University of Illinois at Chicago.
    The Na(+)/H(+) exchanger isoform-3 plays a key role in coupled electroneutral NaCl absorption in the mammalian intestine. Reduced NHE3 expression or function has been implicated in the pathogenesis of diarrhea associated with IBD or enteric infections. Our previous studies revealed transcriptional regulation of NHE3 by various agents such as TNF-, IFN-γ and butyrate involving the transcription factors SP1 and SP3. Read More

    A physics-based model for maintenance of the pH gradient in the gastric mucus layer.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 7:ajpgi.00221.2017. Epub 2017 Sep 7.
    University of Utah.
    It is generally accepted that the gastric mucus layer provides a protective barrier between the lumen and the mucosa, shielding the mucosa from acid and digestive enzymes and preventing auto-digestion of the stomach epithelium. However, the precise mechanisms that contribute to this protective function are still up for debate. In particular, it is not clear what physical processes are responsible for transporting hydrogen protons, secreted within the gastric pits, across the mucus layer to the lumen without acidifying the environment adjacent to the epithelium. Read More

    The antioxidant glutathione protects against enteric neuron death in situ, but its depletion is protective during colitis.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 7:ajpgi.00165.2017. Epub 2017 Sep 7.
    Michigan State University
    Enteric glia play an important neuroprotective role in the enteric nervous system (ENS) by producing neuroprotective compounds such as the antioxidant reduced glutathione (GSH). The specific cellular pathways that regulate glial production of GSH, and how these pathways are altered during, or contribute to, neuroinflammation in situ and in vivo are not fully understood. We investigated this issue using immunohistochemistry to localize GSH synthesis enzymes within the myenteric plexus and tested how the inhibition of GSH synthesis with the selective inhibitor L-Buthionine Sulfoximine (BSO) impacts neuronal survival and inflammation. Read More

    Both NHERF3 and NHERF2 are necessary for multiple aspects of acute regulation of NHE3 by elevated Ca(2+), cGMP and lysophosphatidic acid.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 7:ajpgi.00140.2017. Epub 2017 Sep 7.
    Johns Hopkins University School of Medicine
    The intestinal epithelial brush border Na(+)/H(+) exchanger NHE3 accounts for a large component of intestinal Na absorption. NHE3 is regulated during digestion by signaling complexes on its C-terminus that include the four multi-PDZ domain containing NHERF family proteins. Because the roles of each NHERF appear to vary based on the cell model or intestinal segment studied and because of our recent finding that a NHERF3-NHERF2 heterodimer appears important for NHE3 regulation in Caco-2 cells, we examined the role of NHERF3 and NHERF2 in homozygous C57BL/6 NHERF2 and NHERF3 KO mouse jejunum. Read More

    Zinc strengthens the jejunal barrier by reversibly tightening the paracellular route.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1:ajpgi.00355.2016. Epub 2017 Sep 1.
    Charité - Universitätsmedizin Berlin
    During the post weaning period, piglets are prone to gastrointestinal infections. The resulting impairment of intestinal barrier function may cause diarrhea associated with growth retardation or even death of piglets. Orally applied zinc is commonly used to prevent and treat diarrhea but its mode of action still needs to be elucidated. Read More

    Krüppel-like factor 5 is essential for maintenance of barrier function in mouse colon.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1:ajpgi.00172.2017. Epub 2017 Sep 1.
    Stony Brook University
    Krüppel-like factor 5 (KLF5) is a member of the zinc finger family of transcription factors that regulates homeostasis of the intestinal epithelium. Previous studies suggested an indispensable role of KLF5 in maintaining intestinal barrier function. In the current study, we investigated the mechanisms by which KLF5 regulates colonic barrier function in vivo and in vitro. Read More

    Ethanol metabolism by alcohol dehydrogenase or cytochrome P450 2E1 differentially impairs hepatic protein trafficking and growth hormone signaling.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1:ajpgi.00027.2017. Epub 2017 Sep 1.
    The Catholic University of America
    The liver metabolizes alcohol using alcohol dehydrogenase (ADH) and cytochrome P450 2E1 (CYP2E1). Both enzymes metabolize ethanol into acetaldehyde, but CYP2E1 activity also results in the production of reactive oxygen species (ROS) that promote oxidative stress. We have previously shown that microtubules are hyperacetylated in ethanol-treated polarized, hepatic WIF-B cells and livers from ethanol fed rats. Read More

    New ultrasonographic screening method for oropharyngeal dysphagia : Tissue Doppler imaging.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1:ajpgi.00019.2017. Epub 2017 Sep 1.
    Kawasaki Medical School
    Background: Ultrasound Tissue Doppler imaging (US-TDI) has been used to diagnose regional wall motion (WM) abnormalities in coronary artery disease, but has not been applied to oropharyngeal diseases. This study aimed first to validate an US-TDI method to assess cervical esophageal (CE) WM, and secondly to use the method to evaluate CE WM in patients with oropharyngeal dysphagia (OD).

    Methods: First, we enrolled 22 healthy men (mean age: 59. Read More

    Age Related External Anal Sphincter Muscle Dysfunction & Fibrosis: Possible Role of Wnt-β Catenin Signaling Pathways.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 24:ajpgi.00209.2017. Epub 2017 Aug 24.
    University of California, San Diego.
    Studies show an age-related increase in the prevalence of anal incontinence and sphincter muscle atrophy. Wnt-β catenin signaling pathway has been recently recognized as the major molecular pathway involved in the age-related skeletal muscle atrophy and fibrosis. The goals of our study were to evaluate: (i) impact of normal aging on the EAS muscle length-tension (L-T) function & morphology; and (ii) specifically examine the role of Wnt signaling pathways in anal sphincter muscle fibrosis. Read More

    Ammonia modifies enteric neuromuscular transmission through glial gamma-aminobutyric acid signaling.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 24:ajpgi.00154.2017. Epub 2017 Aug 24.
    Michigan State University
    Objective: Impaired gut motility may contribute, at least in part, to the development of systemic hyperammonemia and systemic neurological disorders in inherited metabolic disorders, or in severe liver and renal disease. It is not known whether enteric neurotransmission regulates intestinal luminal and hence systemic ammonia levels by induced changes in motility.

    Design: Here, we propose and test the hypothesis that ammonia acts through specific enteric circuits to influence gut motility. Read More

    Targeting Palmitoyl acyltransferase ZDHHC21 Improves Gut Epithelial Barrier Dysfunction Resulting from Burn Induced Systemic Inflammation.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 24:ajpgi.00145.2017. Epub 2017 Aug 24.
    University of South Florida Morsani College of Medicine
    Clinical studies in burn patients demonstrate a close association between leaky guts and increased incidence or severity of sepsis and other complications. Severe thermal injury triggers intestinal inflammation that contributes to intestinal epithelial hyperpermeability, which exacerbates systemic response leading to multiple organ failure and sepsis. In this study, we identified a significant function of a particular palmitoyl acyltransferase (PAT), ZDHHC21, in mediating signaling events required for gut hyperpermeability induced by inflammation. Read More

    Effects of NK1 Receptors on Gastric Motor Functions and Satiation in Healthy Humans: Results from a Controlled Trial with the NK1 Antagonist, Aprepitant.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 16:ajpgi.00197.2017. Epub 2017 Aug 16.
    Mayo Clinic
    Aprepitant, an NK1 receptor antagonist, is approved for the treatment of chemotherapy-induced or postoperative emesis by blocking NK1 receptors in the brain stem vomiting center. Effects of NK1 receptors on gastric functions and postprandial symptoms in humans are unclear; a single, crossover study did not show a significant effect of aprepitant on gastrointestinal transit. Our aim was to compare, in a randomized, double-blind, placebo-controlled, parallel-group study (12 healthy volunteers per group), effects of aprepitant vs. Read More

    Am J Physiol Gastrointest Liver Physiol 2017 Aug 10:ajpgi.00428.2016. Epub 2017 Aug 10.
    Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona
    Background And Aims: Rising evidence points to endothelial-to-mesenchymal transition (EndMT) as a significant source of the mesenchymal cell population in fibrotic diseases. In this context, we hypothesized that liver endothelial cells undergo EndMT during fibrosis progression.

    Methods: Cirrhosis in mice was induced by CCl4 A transgenic mouse expressing a red fluorescent protein reporter under the control of Tie2 promoter (Tie2-tdTomato) was used to trace the acquisition of EndMT. Read More

    Hamp1 mRNA and plasma hepcidin levels are influenced by sex and strain but don't predict tissue iron levels in inbred mice.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 10:ajpgi.00307.2016. Epub 2017 Aug 10.
    University of Florida, Gainesville.
    Iron homeostasis is tightly regulated and the peptide hormone hepcidin is considered to be a principal regulator of iron metabolism. Previous studies in a limited number of mouse strains found equivocal sex and strain dependent differences in mRNA and serum levels of hepcidin. Similarly, conflicting data on the relationship between hepcidin (Hamp1) mRNA levels and iron status as assessed by transferrin saturation and tissue iron concentrations were reported. Read More

    Enteric Serotonin and Oxytocin: Endogenous Regulation of Severity in a Murine Model of Necrotizing Enterocolitis.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 3:ajpgi.00215.2017. Epub 2017 Aug 3.
    Columbia University.
    Necrotizing enterocolitis (NEC), a gastrointestinal inflammatory disease of unknown etiology, causes a great deal of morbidity and mortality in premature infants. The liver as well as the gut may be affected in NEC. We tested the hypothesis that signaling molecules, which are endogenous to the bowel, regulate the severity of experimental NEC in mice. Read More

    Relationship of Gastric Emptying or Accommodation with Satiation, Satiety and Postprandial Symptoms in Health.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 3:ajpgi.00190.2017. Epub 2017 Aug 3.
    Mayo Clinic College of Medicine.
    The contributions of gastric emptying (GE) and gastric accommodation (GA) to satiation, satiety, and postprandial symptoms remain unclear. We aimed to evaluate the relationships between GA or GE with satiation, satiety, and postprandial symptoms in healthy overweight or obese volunteers (total n=285, 73% females, mean BMI 33.5kg/m2): 26 prospectively studied obese, otherwise healthy participants and 259 healthy subjects with previous similar GI testing. Read More

    Overactivation of intestinal Sterol Response Element Binding Protein 2 promotes diet-induced non-alcoholic steatohepatitis.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 3:ajpgi.00174.2017. Epub 2017 Aug 3.
    University of illinois at Chicago
    Nonalcoholic fatty liver disease (NAFLD) is characterized by lipid accumulation in the liver that may progress to hepatic fibrosis and nonalcoholic steatohepatitis (NASH). Mechanisms underlying NAFLD and NASH are not yet fully understood. Dietary cholesterol was recently shown to be a risk factor for the development of NASH suggesting a role for intestinal handling of cholesterol. Read More

    Role of G protein-coupled receptors-microRNA interactions in Gastrointestinal Pathophysiology.
    Am J Physiol Gastrointest Liver Physiol 2017 Aug 3:ajpgi.00144.2017. Epub 2017 Aug 3.
    David Geffen School of Medicine at UCLA
    G protein-coupled receptors (GPCRs) make up the largest transmembrane receptor superfamily in the human genome and are expressed in nearly all gastrointestinal (GI) cell types. Coupling of GPCRs and their respective ligands activates various phosphotransferase in the cytoplasm, and thus, activation of GPCR signaling in intestine regulates many cellular and physiological processes. Studies in microRNAs (miRNAs) demonstrate that they represent critical epigenetic regulators of different pathophysiologic responses in different organs and cell types in humans and animals. Read More

    PARP2 deficiency affects invariant-NKT-cell maturation and protects mice from Concanavalin A-induced liver injury.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 27:ajpgi.00436.2016. Epub 2017 Jul 27.
    Excessive or persistent inflammation and hepatocyte death are the key triggers of liver diseases. The poly(ADP-ribose) polymerase (PARP) proteins induce cell death and inflammation. Chemical inhibition of PARP activity protects against liver injury during Concanavalin A (ConA)-induced hepatitis. Read More

    Melatonin inhibits hypothalamic gonandotropin-releasing hormone release and reduces biliary hyperplasia and fibrosis in cholestatic rats.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 27:ajpgi.00421.2016. Epub 2017 Jul 27.
    Baylor Scott & White, Central Texas Veterans Health Care System and Texas A&M HSC
    Melatonin is a hormone produced by the pineal gland with increased circulating levels shown to inhibit biliary hyperplasia and fibrosis during cholestasis. Melatonin also has the capability to suppress the release of hypothalamic gonadotropin releasing hormone (GnRH), a hormone that promotes cholangiocyte proliferation when serum levels are elevated. However, the interplay and contribution of neural melatonin and GnRH to cholangiocyte proliferation and fibrosis in bile duct-ligated (BDL) rats has not been investigated. Read More

    A simple, cost-effective method for generating murine colonic 3D enteroids and 2D monolayers for studies of primary epithelial cell function.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 27:ajpgi.00152.2017. Epub 2017 Jul 27.
    University of Calgary
    Cancer cell lines have been the mainstay of intestinal epithelial experimentation for decades, due primarily to their immortality and ease of culture. However, because of the inherent biological abnormalities of cancer cell lines, many cellular biologists are currently transitioning away from these models, and toward more representative primary cells. This has been particularly challenging, but recent advances in the generation of intestinal organoids have brought the routine use of primary cells within reach of most epithelial biologists. Read More

    Adaptive-regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: Possible involvement of epigenetic mechanism(s).
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 20:ajpgi.00192.2017. Epub 2017 Jul 20.
    UCI/VA Medical Center
    The essentiality of thiamin stems from its roles as a co-factor (mainly in the form of thiamin pyrophosphate, TPP) in critical metabolic reactions including oxidative energy metabolism and reduction of cellular oxidative stress. Like other mammalian cells, pancreatic acinar cells (PAC) obtain thiamin from their surroundings and convert it to TPP; mitochondria then take up TPP by a carrier-mediated process that involves the mitochondrial TPP (MTPP) transporter (MTPPT; product of SLC25A19 gene). Previous studies have characterized different physiological/biological aspects of the MTPP uptake process, but little is known about its possible adaptive-regulation. Read More

    Vagally-mediated effects of brainstem dopamine on gastric tone and phasic contractions of the rat.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 20:ajpgi.00180.2017. Epub 2017 Jul 20.
    Penn State College of Medicine
    Dopamine (DA) containing fibers and neurons are embedded within the brainstem dorsal vagal complex (DVC); we have shown previously that DA modulates the membrane properties of neurons of the dorsal motor nucleus of the vagus (DMV) via DA1 and DA2 receptors. The vagally-dependent modulation of gastric tone and phasic contractions, i.e. Read More

    A novel mouse model of radiation-induced cancer survivorship diseases of the gut.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 20:ajpgi.00113.2017. Epub 2017 Jul 20.
    Clinical Sciences
    A deeper understanding of the radiation-induced pathophysiological processes that develop in the gut is imperative in order to prevent, alleviate or eliminate cancer survivorship diseases after radiotherapy to the pelvic area. Most rodent models of high-dose gastrointestinal radiation injury are limited by high mortality. We therefore established a model that allows for the delivering of radiation in fractions at high doses, while maintaining long-term survival. Read More

    Augmentation of cGMP/PKG Pathway and Colonic Motility by Hydrogen Sulfide.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 13:ajpgi.00161.2017. Epub 2017 Jul 13.
    Virginia Commonwealth University
    Hydrogen sulfide (H2S), like nitric oxide (NO), causes smooth muscle relaxation, but unlike NO, does not stimulate soluble guanylyl cyclase (sGC) activity and generate cGMP. The aim of this study was to investigate the interplay between NO and H2S in colonic smooth muscle. In colonic smooth muscle from rabbit, mouse and human, L-cysteine, substrate of cystathionine-γ-lyase (CSE), or NaHS, an H2S donor, inhibited phosphodiesterase 5 (PDE5) activity and augmented the increase in cGMP levels, IP3 receptor phosphorylation at Ser(1756) (measured as a proxy for PKG activation), and muscle relaxation in response to NO donor, s-nitrosoglutathione (GSNO), suggesting augmentation of cGMP/PKG pathway by H2S. Read More

    Roles of autophagy and metabolism in pancreatic cancer cell adaptation to environmental challenges.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 13:ajpgi.00138.2017. Epub 2017 Jul 13.
    VA Greater Los Angeles Health Care System and University of California
    Pancreatic ductal adenocarcinoma (PDAC) displays extensive and poorly vascularized desmoplastic stromal reaction, and therefore pancreatic cancer (PaCa) cells are confronted with nutrient deprivation and hypoxia. Here, we investigate the roles of autophagy and metabolism in PaCa cell adaptation to environmental stresses, amino acid (AA) depletion and hypoxia. It is known that in healthy cells, basal autophagy is at a low level, but it is greatly activated by environmental stresses. Read More

    Validation and characterization of a novel method for selective vagal deafferentation of the gut.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 13:ajpgi.00095.2017. Epub 2017 Jul 13.
    The John B. Pierce Laboratory
    There is a lack of tools that selectively target vagal afferent neurons (VAN) innervating the gut. We use saporin (SAP), a potent neurotoxin, conjugated to the GI hormone cholecystokinin (CCK-SAP) injected into the nodose ganglia (NG) of male Wistar rats to specifically ablate GI-VAN. We report that CCK-SAP ablates a sub-population of VAN in culture. Read More

    Loss of nitric oxide-mediated inhibition of purine neurotransmitter release in the colon in the absence of interstitial cells of Cajal.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 13:ajpgi.00045.2017. Epub 2017 Jul 13.
    University of Nevada School of Medicine
    Regulation of colonic motility depends upon the integrity of enteric inhibitory neurotransmission mediated by nitric oxide (NO), purine neurotransmitters, and neuropeptides. Intramuscular interstitial cells of Cajal (ICC-IM) and platelet-derived growth factor receptor α-positive (PDGFRα(+)) cells are involved in generating responses to NO and purine neurotransmitters, respectively. Previous studies have suggested a decreased nitrergic and increased purinergic neurotransmission in Kit(W)/Kit(W-v) (W/W(v) ) mice that display lesions in ICC-IM along the gastrointestinal tract. Read More

    Abdominal surgery induced gastric ileus and activation of M1 like macrophages in the gastric myenteric plexus: prevention by central vagal activation in rats.
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 6:ajpgi.00121.2017. Epub 2017 Jul 6.
    Inflammation plays a role in abdominal surgery (AS)-induced intestinal ileus that is alleviated by electrical vagal stimulation. The stable thyrotropin-releasing hormone agonist, RX77368 injected intracisternally (ic) activates dorsal motor nucleus neurons and gastric vagal efferent discharges. We investigated the gastric inflammation induced by AS and the modulation by ic RX-77368 in rats. Read More

    Dclk1-expressing tuft cells: Critical modulators of the intestinal niche?
    Am J Physiol Gastrointest Liver Physiol 2017 Jul 6:ajpgi.00073.2017. Epub 2017 Jul 6.
    Klinikum rechts der Isar, TU München
    Dclk1-expressing tuft cells constitute a unique intestinal epithelial lineage that is distinct from enterocytes, Paneth cells, goblet cells, and enteroendocrine cells. Tuft cells express taste-related receptors and distinct transcription factors, and interact closely with the enteric nervous system, suggesting a chemosensory cell lineage. In addition, recent work has shown that tuft cells interact closely with cells of the immune system, with a critical role in the cellular regulatory network governing responses to luminal parasites. Read More

    Determinants of post-prandial plasma bile acid kinetics in human volunteers.
    Am J Physiol Gastrointest Liver Physiol 2017 Jun 29:ajpgi.00157.2017. Epub 2017 Jun 29.
    Technische Universität München.
    Bile acids (BA) are signaling molecules with a wide range of biological effects, also identified amongst the most responsive plasma metabolites in the post-prandial state. We here describe this response to different dietary challenges and report on key determinants linked to its inter-individual variability. Healthy men and women (N=72, 62 ± 8 years) were enrolled into a 12-week weight loss intervention. Read More

    Dysfunctional neutrophil effector organelle mobilization and microbicidal protein release in alcohol-related cirrhosis.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 22;313(3):G203-G211. Epub 2017 Jun 22.
    Institute of Liver Studies and Transplantation, King's College London School of Medicine at King's College Hospital, Denmark Hill, London, United Kingdom
    Patients with alcohol-related cirrhosis (ALD) are prone to infection. Circulating neutrophils in ALD are dysfunctional and predict development of sepsis, organ dysfunction, and survival. Neutrophil granules are important effector organelles containing a toxic array of microbicidal proteins, whose controlled release is required to kill microorganisms while minimizing inflammation and damage to host tissue. Read More

    Does acid-base equilibrium correlate with remnant liver volume during stepwise liver resection?
    Am J Physiol Gastrointest Liver Physiol 2017 Jun 22:ajpgi.00110.2017. Epub 2017 Jun 22.
    Heidelberg University
    Small for size and flow syndrome (SFSF) is one of the most challenging complications following extended hepatectomy (EH). After EH, hepatic artery flow decreases and portal vein flow increases per 100 gram remnant liver volume (RLV). This causes hypoxia followed by metabolic acidosis. Read More

    Consumption of a High-Iron Diet Disrupts Homeostatic Regulation of Intestinal Copper Absorption in Adolescent Mice.
    Am J Physiol Gastrointest Liver Physiol 2017 Jun 15:ajpgi.00169.2017. Epub 2017 Jun 15.
    University of Florida
    High-iron feeding of rodents has been commonly used to model human iron-overload disorders. We recently noted that high-iron consumption impaired growth and caused severe systemic copper deficiency in growing rats, but the mechanism by which this occurred could not be determined due to technical limitations. In the current investigation, we thus utilized mice; first to determine if the same phenomenon occurred in another mammalian species, and secondly since we could assess in vivo copper absorption in mice. Read More

    Characterization and mechanisms of the supragastric belch in the cat.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 15;313(3):G220-G229. Epub 2017 Jun 15.
    Medical College of Wisconsin Dysphagia Institute, Division of Gastroenterology and Hepatology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin.
    A response in which a belch occurs without gastric involvement, i.e., the supragastric belch (SGB), has been characterized in humans. Read More

    Activated Notch signaling cascade is correlated with stem cell differentiation toward absorptive progenitors after massive small bowel resection in a rat.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 15;313(3):G247-G255. Epub 2017 Jun 15.
    Department of Pediatric Surgery, Chelsea Children's Hospital, Chelsea and Westminster Healthcare, National Health Service Foundation Trust, Imperial College London, United Kingdom; and.
    Notch signaling is thought to act to drive cell versification in the lining of the small intestine. The purpose of the present study was to evaluate the role of the Notch signaling pathway in stem cell differentiation in the late stages of intestinal adaptation after massive small bowel resection in a rat. Male Sprague-Dawley rats were randomly assigned to one of two experimental groups of eight rats each: Sham rats underwent bowel transection and reanastomosis, while SBS rats underwent 75% small bowel resection. Read More

    RNA-seq implicates deregulation of the immune system in the pathogenesis of diverticulitis.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 15;313(3):G277-G284. Epub 2017 Jun 15.
    Division of Colon and Rectal Surgery, Department of Surgery, Pennsylvania State University College of Medicine, Hershey, Pennsylvania;
    Individuals with diverticula or outpouchings of the colonic mucosa and submucosa through the colonic wall have diverticulosis, which is usually asymptomatic. In 10-25% of individuals, the diverticula become inflamed, resulting in diverticulitis. Very little is known about the pathophysiology or gene regulatory pathways involved in the development of diverticulitis. Read More

    The liver in regulation of iron homeostasis.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 8;313(3):G157-G165. Epub 2017 Jun 8.
    Liver Disease and Iron Disorders Research Group, Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology, Brisbane, Australia
    The liver is one of the largest and most functionally diverse organs in the human body. In addition to roles in detoxification of xenobiotics, digestion, synthesis of important plasma proteins, gluconeogenesis, lipid metabolism, and storage, the liver also plays a significant role in iron homeostasis. Apart from being the storage site for excess body iron, it also plays a vital role in regulating the amount of iron released into the blood by enterocytes and macrophages. Read More

    Functional morphology of the lower esophageal sphincter and crural diaphragm determined by three-dimensional high-resolution esophago-gastric junction pressure profile and CT imaging.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1;313(3):G212-G219. Epub 2017 Jun 1.
    Department of Medicine, University of California, San Diego, California; and.
    The smooth muscles of the lower esophageal sphincter (LES) and skeletal muscles of the crural diaphragm (CD) provide a closure/antireflux barrier mechanism at the esophago-gastric junction (EGJ). A number of questions in regard to the pressure profile of the LES and CD remain unclear, e.g. Read More

    CDX2 upregulates SLC26A3 gene expression in intestinal epithelial cells.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1;313(3):G256-G264. Epub 2017 Jun 1.
    Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois;
    SLC26A3 [downregulated in adenoma (DRA)] plays a key role in mammalian intestinal NaCl absorption, in that it mediates apical membrane Cl(-)/[Formula: see text] exchange. DRA function and expression are significantly decreased in diarrhea associated with inflammatory bowel disease. DRA is also considered to be a marker of cellular differentiation and is predominantly expressed in differentiated epithelial cells. Read More

    Ductular and proliferative response of esophageal submucosal glands in a porcine model of esophageal injury and repair.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1;313(3):G180-G191. Epub 2017 Jun 1.
    Division of Gastroenterology, Department of Medicine, Duke University, Durham, North Carolina; and
    Esophageal injury is a risk factor for diseases such as Barrett's esophagus (BE) and esophageal adenocarcinoma. To improve understanding of signaling pathways associated with both normal and abnormal repair, animal models are needed. Traditional rodent models of esophageal repair are limited by the absence of esophageal submucosal glands (ESMGs), which are present in the human esophagus. Read More

    Oatmeal particle size alters glycemic index but not as a function of gastric emptying rate.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 1;313(3):G239-G246. Epub 2017 Jun 1.
    Institute of Food Research, Norwich Research Park, Norwich, United Kingdom.
    The aim of this study was to determine the extent to which oat particle size in a porridge could alter glucose absorption, gastric emptying, gastrointestinal hormone response, and subjective feelings of appetite and satiety. Porridge was prepared from either oat flakes or oat flour with the same protein, fat, carbohydrate, and mass. These were fed to eight volunteers on separate days in a crossover study, and subjective appetite ratings, gastric contents, and plasma glucose, insulin, and gastrointestinal hormones were determined over a period of 3 h. Read More

    Anti-inflammatory effects and mechanisms of vagal nerve stimulation combined with electroacupuncture in a rodent model of TNBS-induced colitis.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 25;313(3):G192-G202. Epub 2017 May 25.
    Veterans Research and Education Foundation, Veterans Affairs Medical Center, Oklahoma City, Oklahoma;
    The purpose of this study was to determine the effects and mechanisms of vagal nerve stimulation (VNS) and additive effects of electroacupuncture (EA) on colonic inflammation in a rodent model of IBD. Chronic inflammation in rats was induced by intrarectal TNBS (2,4,6-trinitrobenzenesulfonic acid). The rats were then treated with sham ES (electrical stimulation), VNS, or VNS + EA for 3 wk. Read More

    High-resolution mapping of gastric slow-wave recovery profiles: biophysical model, methodology, and demonstration of applications.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 25;313(3):G265-G276. Epub 2017 May 25.
    Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
    Slow waves play a central role in coordinating gastric motor activity. High-resolution mapping of extracellular potentials from the stomach provides spatiotemporal detail on normal and dysrhythmic slow-wave patterns. All mapping studies to date have focused exclusively on tissue activation; however, the recovery phase contains vital information on repolarization heterogeneity, the excitable gap, and refractory tail interactions but has not been investigated. Read More

    Disease activity in eosinophilic esophagitis is associated with impaired esophageal barrier integrity.
    Am J Physiol Gastrointest Liver Physiol 2017 Sep 25;313(3):G230-G238. Epub 2017 May 25.
    Department of Gastroenterology and Hepatology, Academic Medical Centre, Amsterdam, The Netherlands.
    In eosinophilic esophagitis (EoE), the esophageal barrier integrity is impaired. Integrity can be assessed with different techniques. To assess the correlations between esophageal eosinophilia and various measures of mucosal integrity and to evaluate whether endoscopic impedance measurements can predict disease activity, endoscopies and mucosal integrity measurements were performed in adult EoE patients with active disease (≥15 eosinophils/high-power field) at baseline (n = 32) and after fluticasone (n = 15) and elemental dietary treatment (n = 14) and in controls (n = 19). Read More

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