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Paulraj RS, Afroz S, Palaniappan B, Murughiyan U, Singh S, Arthur S, Sundaram U. Intestinal Epithelial Cell Brush Border Membrane Cl:HCO 3 Exchanger Regulation by Mast Cells in Chronic Ileitis. Int J Mol Sci 2024; 25:11208. [PMID: 39456989 PMCID: PMC11508389 DOI: 10.3390/ijms252011208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2024] [Revised: 09/30/2024] [Accepted: 10/06/2024] [Indexed: 10/28/2024] Open
Abstract
Malabsorption of NaCl is the primary cause of diarrhea in inflammatory bowel disease (IBD). Coupled NaCl absorption occurs via the dual operation of Na:H and Cl:HCO3 exchange in the brush border membrane (BBM) of villus cells. Cl:HCO3 exchange is mediated by BBM transporters DRA (downregulated in adenoma) and PAT1 (putative anion transporter 1) in the mammalian small intestine. DRA/PAT1-mediated Cl:HCO3 exchange was significantly downregulated in the BBM of villus cells in a rabbit model of chronic ileitis, while Na:H exchange was unaffected. The inhibition of Cl:HCO3 exchange was restored in the rabbits when treated with a broad-spectrum immunomodulator, i.e. a glucocorticoid, indicating that the downregulation of DRA/PAT1 is likely to be immune-mediated during chronic enteritis. Mucosal mast cells are one type of key immune cells that are known to proliferate and release immune inflammatory mediators, thus playing a significant role in the pathogenesis of IBD. However, how mast cells may regulate DRA- and PAT1-mediated Cl:HCO3 exchange in a rabbit model of chronic ileitis is unknown. In this study, treatment of rabbits with chronic intestinal inflammation with the mast cell stabilizer ketotifen did not affect the mucosal architecture of the inflamed intestine. However, ketotifen treatment reversed the inhibition of Cl:HCO3 activity in the BBM of villus cells. This restoration of Cl:HCO3 activity to normal levels by ketotifen was found to be secondary to restoring the affinity of the exchangers for its substrate chloride. This observation was consistent with molecular studies, where the mRNA and BBM protein expressions of DRA and PAT1 remained unaffected in the villus cells under all experimental conditions. Thus, this study indicates that mast cells mediated the inhibition of coupled NaCl absorption by inhibiting Cl:HCO3 exchange in a rabbit model of chronic enteritis.
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Affiliation(s)
- Raja Singh Paulraj
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA (B.P.); (U.M.)
| | - Sheuli Afroz
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA (B.P.); (U.M.)
| | - Balasubramanian Palaniappan
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA (B.P.); (U.M.)
| | - Usha Murughiyan
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA (B.P.); (U.M.)
- Department of Internal Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA
| | - Soudamani Singh
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA (B.P.); (U.M.)
| | - Subha Arthur
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA (B.P.); (U.M.)
| | - Uma Sundaram
- Department of Clinical and Translational Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA (B.P.); (U.M.)
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Rahman MM, Afroz S, Arthur S, Sundaram U. Mast Cell Mediated Regulation of Small Intestinal Chloride Malabsorption in SAMP1/YitFc Mouse Model of Spontaneous Chronic Ileitis. Cells 2021; 10:cells10030697. [PMID: 33801010 PMCID: PMC8004028 DOI: 10.3390/cells10030697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/13/2021] [Accepted: 03/18/2021] [Indexed: 12/19/2022] Open
Abstract
In Inflammatory Bowel Disease (IBD), malabsorption of electrolytes (NaCl) results in diarrhea. Inhibition of coupled NaCl absorption, mediated by the dual operation of Na:H and Cl:HCO3 exchangers on the brush border membrane (BBM) of the intestinal villus cells has been reported in IBD. In the SAMP1/YitFcs (SAMP1) mice model of spontaneous ileitis, representing Crohn’s disease, DRA (Downregulated in Adenoma) mediated Cl:HCO3 exchange was shown to be inhibited secondary to diminished affinity of the exchanger for Cl. However, NHE3 mediated Na:H exchange remained unaffected. Mast cells and their secreted mediators are known to be increased in the IBD mucosa and can affect intestinal electrolyte absorption. However, how mast cell mediators may regulate Cl:HCO3 exchange in SAMP1 mice is unknown. Therefore, the aim of this study was to determine the effect of mast cell mediators on the downregulation of DRA in SAMP1 mice. Mast cell numbers and their degranulation marker enzyme (β-hexosaminidase) levels were significantly increased in SAMP1 mice compared to control AKR mice. However, treatment of SAMP1 mice with a mast cell stabilizer, ketotifen, restored the β-hexosaminidase enzyme levels to normal in the intestine, demonstrating stabilization of mast cells by ketotifen. Moreover, downregulation of Cl:HCO3 exchange activity was restored in ketotifen treated SAMP1 mice. Kinetic studies showed that ketotifen restored the altered affinity of Cl:HCO3 exchange in SAMP1 mice villus cells thus reinstating its activity to normal. Further, RT-qPCR, Western blot and immunofluorescence studies showed that the expression levels of DRA mRNA and BBM protein, respectively remained unaltered in all experimental conditions, supporting the kinetic data. Thus, inhibition of Cl:HCO3 exchange resulting in chloride malabsorption leading to diarrhea in IBD is likely mediated by mast cell mediators.
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Reduced neurons in the ileum of proctocolectomized rat models. Med Mol Morphol 2014; 48:155-63. [PMID: 25432768 DOI: 10.1007/s00795-014-0093-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/31/2014] [Indexed: 10/24/2022]
Abstract
Ileal pouch-anal anastomosis (IPAA) is the operation of choice following proctocolectomy for patients who suffer from ulcerative colitis and familial adenomatous polyposis. The aim of this study was to morphologically examine the neurons, endocrine cells and mast cells in the ileum of rats subjected to proctocolectomy followed by three different types of ileoanal anastomosis. Rats were subjected to either sham operation or proctocolectomy followed by ileoanal anastomosis end-to-end, side-to-end or IPAA (J-pouch). In comparison to sham-operated rats, the body weight was reduced in rats that underwent proctocolectomy with end-to-end or side-to-end, but not IPAA procedure. In all three models of ileoanal anastomosis, the ileum displayed crypt hyperplasia with a chronic inflammatory infiltrate located in the interstitium, hyperplasia of goblet cells, but reduced protein gene product 9.5 (PGP 9.5)-immunoreactive neurons in the mucosa as well as submucosa. Numbers of endocrine cells in the mucosa (chromogranin A immunostaining) and mast cells in the mucosa and submucosa (Astra blue staining) were unchanged after proctocolectomy. In conclusion, neurons, but neither endocrine cells nor mast cells, were reduced in the ileum of proctocolectomized rats followed by either of three different types of ileoanal anastomosis.
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Abstract
The gastrointestinal tract is innervated by several distinct populations of neurons, whose cell bodies either reside within (intrinsic) or outside (extrinsic) the gastrointestinal wall. Normally, most individuals are unaware of the continuous, complicated functions of these neurons. However, for patients with gastrointestinal disorders, such as IBD and IBS, altered gastrointestinal motility, discomfort and pain are common, debilitating symptoms. Although bouts of intestinal inflammation underlie the symptoms associated with IBD, increasing preclinical and clinical evidence indicates that infection and inflammation are also key risk factors for the development of other gastrointestinal disorders. Notably, a strong correlation exists between prior exposure to gut infection and symptom occurrence in IBS. This Review discusses the evidence for neuroplasticity (structural, synaptic or intrinsic changes that alter neuronal function) affecting gastrointestinal function. Such changes are evident during inflammation and, in many cases, long after healing of the damaged tissues, when the nervous system fails to reset back to normal. Neuroplasticity within distinct populations of neurons has a fundamental role in the aberrant motility, secretion and sensation associated with common clinical gastrointestinal disorders. To find appropriate therapeutic treatments for these disorders, the extent and time course of neuroplasticity must be fully appreciated.
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Martínez-Augustin O, Romero-Calvo I, Suárez MD, Zarzuelo A, de Medina FS. Molecular bases of impaired water and ion movements in inflammatory bowel diseases. Inflamm Bowel Dis 2009; 15:114-27. [PMID: 18626965 DOI: 10.1002/ibd.20579] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The intestine is dedicated to the absorption of water and nutrients. Fine tuning of this process is necessary to maintain an adequate balance and inflammation disrupts the equilibrium. This review summarizes the current evidence in this field. Classical mechanisms proposed include alteration of epithelial integrity, augmented secretion, and reduced absorption. In addition, intestinal inflammation is associated with defects in epithelial barrier function. However, our understanding of the phenomenon has been complicated by the fact that ionic secretion is in fact diminished in vivo, even after inflammation has subsided. Inhibited ionic secretion can be reversed partially or totally in vitro by maneuvers such as blockade of inducible nitric oxide synthase or removal of the submucosal layer. Disturbances in ionic absorption are less well characterized but clearly involve both electroneutral and electrogenic Na(+) absorption. Altered ionic transport is associated with changes in the expression and function of the transporters, including the Na(+)/K(+) ATPase, the sodium/potassium/chloride cotransporter 1 (NKCC1), the sodium/hydrogen exchanger 3 (NHE3), and the epithelial sodium channel (ENaC), as well as to the modulation of intracellular signaling. Further investigation is needed in this area in order to provide an integrated paradigm of ionic transport in the inflamed intestine. In particular, we do not know exactly how diarrhea ensues in inflammation and, consequently, we do not have specific pharmacological tools to combat this condition effectively and without side effects. Moreover, whether transport disturbances are reversible independently of inflammatory control is unknown.
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Affiliation(s)
- Olga Martínez-Augustin
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
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Feng BS, He SH, Zheng PY, Wu L, Yang PC. Mast cells play a crucial role in Staphylococcus aureus peptidoglycan-induced diarrhea. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 171:537-47. [PMID: 17600127 PMCID: PMC1934528 DOI: 10.2353/ajpath.2007.061274] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bacterium-induced diarrhea results in 2 to 2.5 million deaths in the world each year. The mechanism needs to be further understood. Staphylococcus aureus infection has a close relation with diarrhea; its cell wall component peptidoglycan (PGN) has strong biological activity on immune cells and possibly plays a role in S. aureus-induced diarrhea. The present study showed that oral PGN-induced diarrhea in mice in a dose-dependent manner. Intestinal epithelial cells absorbed PGN via the intracellular pathway. Intestinal mast cells were activated after PGN gavage. Toll-like receptor (TLR)2 expression was detected in mast cells in the intestine as well as in the murine mast cell line p815 cells. Blocking TLR2 or nucleotide-binding oligomerization domain (NOD)1 with related antibodies or RNA interference abolished PGN-induced p815 cell activation. The mast cell mediator histamine and serotonin had synergistic effects in PGN-induced diarrhea. In summary, oral PGN can induce diarrhea in mice, and TLR2 and NOD1 mediate the PGN-induced mast cell activation that plays a critical role in diarrhea induction. Blockade of TLR2 or NOD1 or treating mice with a mast cell stabilizer can efficiently inhibit PGN-induced-diarrhea, providing potential therapeutic significance.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Administration, Oral
- Animals
- Blotting, Western
- Cell Degranulation/drug effects
- Cells, Cultured
- Diarrhea/chemically induced
- Diarrhea/metabolism
- Diarrhea/prevention & control
- Dose-Response Relationship, Drug
- Drug Synergism
- Gene Expression
- Histamine H1 Antagonists/pharmacology
- Intestinal Mucosa/metabolism
- Intestinal Mucosa/ultrastructure
- Intracellular Fluid/metabolism
- Ketotifen/pharmacology
- Mast Cells/drug effects
- Mast Cells/metabolism
- Mast Cells/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Mice, Knockout
- Microscopy, Electron
- Nod1 Signaling Adaptor Protein/genetics
- Nod1 Signaling Adaptor Protein/metabolism
- Peptidoglycan/administration & dosage
- Peptidoglycan/metabolism
- Peptidoglycan/toxicity
- Reverse Transcriptase Polymerase Chain Reaction
- Serotonin Antagonists/pharmacology
- Staphylococcus aureus/chemistry
- Toll-Like Receptor 2/genetics
- Toll-Like Receptor 2/metabolism
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Affiliation(s)
- Bai-Sui Feng
- Department of Pathology, McMaster University, Hamilton, Ontario, Canada
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Ramos L, Vicario M, Santos J. [Stress-mast cell axis and regulation of gut mucosal inflammation: from intestinal health to an irritable bowel]. Med Clin (Barc) 2007; 129:61-9. [PMID: 17588364 DOI: 10.1157/13106939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The functional gastrointestinal disorders and the irritable bowel syndrome, in particular, represent one of the commonest causes of medical consultation and the most frequent diagnosis raised by the gastroenterologists. Despite their high prevalence, the aetiology and pathophysiology of these functional digestive disorders remains unclear and specific diagnostic markers and clearly effective therapeutic options are lacking as well. These factors generate an important impairment in the quality of life in these patients and a growing sanitary burden. Recent studies showing the presence of low grade intestinal mucosal inflammation along with mast cell hyperplasia may contribute to the development and perpetuation of visceral hypersensitivity and dismotility patterns and epithelial barrier abnormalities, characteristic of the irritable bowel syndrome. In this article we will review the role of the stress-mast cell axis in the modulation of the gut mucosal inflammation and in the pathophysiology of the irritable bowel syndrome.
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Affiliation(s)
- Laura Ramos
- Unidad de Investigación en Enfermedades Digestivas, Servicio de Aparato Digestivo, Hospital Universitari Vall d'Hebron, Departamento de Medicina, Universitat Autònoma de Barcelona, Barcelona, España
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Abstract
The investigative evidence and emerging concepts in neurogastroenterology implicate dysfunctions at the levels of the enteric and central nervous systems as underlying causes of the prominent symptoms of many of the functional gastrointestinal disorders. Neurogastroenterological research aims for improved understanding of the physiology and pathophysiology of the digestive subsystems from which the arrays of functional symptoms emerge. The key subsystems for defecation-related symptoms and visceral hyper-sensitivity are the intestinal secretory glands, the musculature and the nervous system that controls and integrates their activity. Abdominal pain and discomfort arising from these systems adds the dimension of sensory neurophysiology. This review details current concepts for the underlying pathophysiology in terms of the physiology of intestinal secretion, motility, nervous control, sensing function, immuno-neural communication and the brain-gut axis.
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Venkova K, Greenwood-van Meerveld B. Long-lasting changes in small intestinal transport following the recovery from Trichinella spiralis infection. Neurogastroenterol Motil 2006; 18:234-42. [PMID: 16487415 DOI: 10.1111/j.1365-2982.2005.00753.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Changes in intestinal motility and visceral sensitivity are found after resolution of acute enteric inflammation. The study investigates whether a transient nematode-induced intestinal inflammation may result in long-lasting remodelling of epithelial transport. Ferrets infected with Trichinella spiralis or sham-infected animals were euthanized on day 10, 30 or 60 postinfection (PI) and the jejunum was isolated. The net transport of electrolytes was measured electrophysiologically as transmucosal short-circuit current (I(sc)) and responses to electrical field stimulation (EFS: 1-32 Hz) or secretagogues were investigated. Myeloperoxidase (MPO) activity, a marker of mucosal inflammation, was maximal during the enteric stage of T. spiralis infection (day 10 PI) and returned to normal on days 30 and 60 PI. Mucosal inflammation caused a reduction in basal I(sc), increased electrical conductance (G) and decreased the maximal responses to EFS, carbachol or histamine. On days 30 and 60 PI the inflammation resolved and basal electrogenic transport appeared normal; however, the secretion induced by EFS, carbachol or histamine remained suppressed. Moreover, EFS-induced responses were shifted from predominantly cholinergic in controls to non-cholinergic in the infected animals. The results suggest that a transient small intestinal inflammation causes a long-term remodelling of epithelial function.
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Affiliation(s)
- K Venkova
- Oklahoma Center for Neuroscience, VA Medical Center, University of Oklahoma Health Science Center, Oklahoma City, OK 73104, USA
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Addou-Benounane S, Tomé D, Kheroua O, Saidi D. Parenteral immunization to beta-lactoglobulin modifies the intestinal structure and mucosal electrical parameters in rabbit. Int Immunopharmacol 2004; 4:1559-63. [PMID: 15351325 DOI: 10.1016/j.intimp.2004.07.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2004] [Revised: 06/25/2004] [Accepted: 07/08/2004] [Indexed: 10/26/2022]
Abstract
Systemic and local immune responses and the intestinal structure were examined in parenterally beta-Lg-sensitized rabbits. Immunization led to high IgG titers against beta-Lg. In a Ussing chamber, a sensitized ileum had a higher short-circuit current (Isc) and potential difference (PD) than a control following in vitro beta-Lg challenge. Histological study indicated that presence of the sensitizing antigen affected and considerably modified the structure of the intestinal mucosa in sensitized rabbits when compared to controls. These alterations were revealed by active atrophy and marked infiltration of the lymphocytes. These findings indicate that antigen exposure results in morphological changes and abnormalities affecting the transport of water and electrolytes. This study provides a clearer understanding of the physiopathological mechanisms of allergy to cow's milk protein.
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Affiliation(s)
- Samia Addou-Benounane
- Laboratoire de Physiologie de la Nutrition et de Sécurité Alimentaire, Département de Biologie, Faculté des Sciences, University of Oran Es-Sénia, Algeria
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Madden KB, Yeung KA, Zhao A, Gause WC, Finkelman FD, Katona IM, Urban JF, Shea-Donohue T. Enteric nematodes induce stereotypic STAT6-dependent alterations in intestinal epithelial cell function. THE JOURNAL OF IMMUNOLOGY 2004; 172:5616-21. [PMID: 15100305 DOI: 10.4049/jimmunol.172.9.5616] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infection with gastrointestinal nematodes exerts profound effects on both the immune and physiological responses of the host. We showed previously that the Th2 cytokines, IL-4 and IL-13, induce STAT6-dependent changes in intestinal epithelial cell permeability, absorption, and secretion that are similar to those observed in a secondary infection with Heligmosomoides polygyrus. In the current study we investigated whether nematode-induced effects on epithelial cell function were 1) generic, 2) dependent upon STAT6, and 3) attributable to direct effects on the epithelial cells themselves or mediated by effects on enteric nerves. Our results demonstrate that infection of BALB/c mice with three different gastrointestinal nematodes (H. polygyrus, Nippostrongylus brasiliensis, and Trichinella spiralis) alters intestinal epithelial cell function by decreasing resistance, glucose absorption, and secretory responses to 5-hydroxytryptamine and acetylcholine, two critical mediators in the submucosal reflex pathway. These modified responses are dependent on STAT6 and are the result of both direct effects and indirect effects mediated through enteric nerves.
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Affiliation(s)
- Kathleen B Madden
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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12
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Abstract
Widespread symptoms associated with the irritable bowel syndrome (IBS) are abnormal defecation and abdominal pain, both of which can be exacerbated by psychogenic stress. Disordered defecation may present as diarrhea or constipation. A subgroup of IBS patients alternate from one to the other over time. Urgency to stool often accompanies the diarrheal-state, and patients with the constipation-predominant form of IBS report straining and the feeling of incomplete evacuation. Basic scientific research aims for improved understanding of the physiology and pathophysiology of the digestive systems from which the arrays of IBS symptoms emerge. The key systems for the defecation-related symptoms are the intestinal secretory glands, the musculature, and the nervous system that controls and integrates their activity. Abdominal pain and discomfort arising from these systems adds the dimension of sensory neurophysiology. This review details current concepts of the underlying pathophysiology in terms of the physiology of intestinal secretion, motility, nervous control, sensing function, immuno-neural communication, and the brain-gut axis.
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Affiliation(s)
- Jackie D Wood
- Departments of Physiology and Cell Biology and Internal Medicine, Ohio State University College of Medicine and Public Health, Columbus, Ohio, USA.
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Francois A, Ksas B, Aigueperse J, Griffiths NM. The recovery of the neurally evoked secretory response of rat colonic mucosa after irradiation is independent of mast cells. Radiat Res 2002; 157:266-74. [PMID: 11839088 DOI: 10.1667/0033-7587(2002)157[0266:trotne]2.0.co;2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The ability of the enteric submucosal plexus to influence the transport of water and electrolytes in the colon was investigated in rats for 1 week after acute whole-body gamma irradiation. The involvement of neuroimmune links in the epithelial responses to nerve stimulation was confirmed by the sensitivity of the tissue to tetrodotoxin, mepyramine and doxantrazole. At 1 and 3 days after irradiation, colon tissues were hyporesponsive to nerve stimulation. This was associated with a drastic diminution of mucosal mast cell numbers, tissue histamine levels, and rat mast cell protease II (RMCP II) levels, and by a decreased maximal epithelial response to exogenously added histamine. The responses to electric-field stimulation were insensitive to both mepyramine and doxantrazole. At 7 days, neurally evoked responses recovered, despite the virtual absence of mast cells, tissue histamine and RMCP II, and the continuing decreased response to histamine. The responses were insensitive to doxantrazole but were decreased by mepyramine. This study showed that the establishment of a normal epithelial response to neural stimulation can occur despite the radiation-induced depletion of mucosal mast cells. The recovery of the epithelial response, which was sensitive to mepyramine, may be ascribed to the reappearance of an unknown histaminergic pathway, which probably has indirect effects on epithelial transport but is independent of nerve-mast cell connections.
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Affiliation(s)
- Agnès Francois
- Unité Mixte d'Etude des Tissus Sains Irradiés, Institut Gustave Roussy, 39 rue Camille Desmoulins, 94 800 Villejuif, France.
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14
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Faussone-Pellegrini MS, Gay J, Vannucchi MG, Corsani L, Fioramonti J. Alterations of neurokinin receptors and interstitial cells of Cajal during and after jejunal inflammation induced by Nippostrongylus brasiliensis in the rat. Neurogastroenterol Motil 2002; 14:83-95. [PMID: 11874557 DOI: 10.1046/j.1365-2982.2002.00306.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Substance P (SP) and its receptors NK1 and NK2 are widely expressed in the intestinal wall by neurones, interstitial cells of Cajal (ICC) and smooth muscle cells. Changes in SP and/or its NK receptors have been documented during experimental inflammation in animals or inflammatory bowel diseases in humans, but the data concern the acute phase of the inflammatory process. We determined immunohistochemically whether NK receptors and SP were altered in the muscle coat during jejunal inflammation induced by the nematode Nippostrongylus brasiliensis and whether these alterations persisted when inflammation had spontaneously resolved 30 days postinfection. An ultrastructural analysis was also conducted on ICC, nerves and muscle. At day 14, when inflammation peaked, there was a reduction in NK1 receptors in myenteric neurones and in SP-immunoreactive nerve endings. There were also ultrastructural anomalies in synaptic vesicles and NK2 receptor loss in the circular muscle layer. The SP decrease persisted at day 30, whereas neurones and circular muscle cells re-expressed NK1 and NK2 receptors, respectively. The ICC at the deep muscular plexus, located near to the inflammatory site, underwent alterations leading to their complete loss at day 30. These morphological changes are probably associated with impairment in tachykinergic control of jejunal functions leading to the alterations of motility and sensitivity to distension already described in these animals.
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Affiliation(s)
- M S Faussone-Pellegrini
- Department of Human Anatomy, Histology and Forensic Medicine, University of Florence, Florence, Italy
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15
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Palmer JM, Greenwood-Van Meerveld B. Integrative neuroimmunomodulation of gastrointestinal function during enteric parasitism. J Parasitol 2001; 87:483-504. [PMID: 11426710 DOI: 10.1645/0022-3395(2001)087[0483:inogfd]2.0.co;2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Enteric helminths have a significant impact on the structure, function, and neural control of the gastrointestinal (GI) tract of the host. Interactions between the host's nervous and immune systems redirect activity in neuronal circuits intrinsic to the gut into an alternative repertoire of defensive and adaptive motor programs. Gut inflammation and activation of the enteric neuroimmune axis play integral roles in the dynamic interaction between host and parasite that occurs at the mucosal surface. Three inter-related themes are stressed in this review to underscore the pivotal role that neural control mechanisms play in the host's GI tract functional responses to enteric parasitism. First, we address the discovery that signaling molecules of both parasite and host origin can reorient the dynamic ecology of enteric host-parasite interactions. Second, we explore what has been learned from investigations of altered gut propulsive and secretomotor reflex activities that occur during enteric parasitic infections and the emerging picture derived from these studies that elucidates how nerves help facilitate and orchestrate functional reorganization of the parasitized gut. Third, we provide an overview of the direct impact that enteric parasitism has on nerve cell function and neurotransmission pathways in both the enteric and central nervous systems of the host. In summary, this review highlights and clarifies the complex mechanisms underlying integrative neuroimmunophysiological responses to the presence of both invasive and noninvasive enteric helminths and identifies directions for future research investigations in this highly important but understudied area.
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Affiliation(s)
- J M Palmer
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska 68178, USA
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16
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Finkelman FD, Shea-Donohue T, Goldhill J, Sullivan CA, Morris SC, Madden KB, Gause WC, Urban JF. Cytokine regulation of host defense against parasitic gastrointestinal nematodes: lessons from studies with rodent models. Annu Rev Immunol 2001; 15:505-33. [PMID: 9143698 DOI: 10.1146/annurev.immunol.15.1.505] [Citation(s) in RCA: 531] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Studies with rodents infected with Trichinella spiralis, Heligmosomoides polygyrus, Nippostronglyus brasiliensis, and Trichuris muris have provided considerable information about immune mechanisms that protect against parasitic gastrointestinal nematodes. Four generalizations can be made: 1. CD4+ T cells are critical for host protection; 2. IL-12 and IFN-gamma inhibit protective immunity; 3. IL-4 can: (a) be required for host protection, (b) limit severity of infection, or (c) induce redundant protective mechanisms; and 4. Some cytokines that are stereotypically produced in response to gastrointestinal nematode infections fail to enhance host protection against some of the parasites that elicit their production. Host protection is redundant at two levels: 1. IL-4 has multiple effects on the immune system and on gut physiology (discussed in this review), more than one of which may protect against a particular parasite; and 2. IL-4 is often only one of multiple stimuli that can induce protection. Hosts may have evolved the ability to recognize features that characterize parasitic gastrointestinal nematodes as a class as triggers for a stereotypic cytokine response, but not the ability to distinguish features of individual parasites as stimuli for more specific protective cytokine responses. As a result, hosts deploy a set of defense mechanisms against these parasites that together control infection by most members of that class, even though a specific defense mechanism may not be required to defend against a particular parasite and may even damage a host infected with that parasite.
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Affiliation(s)
- F D Finkelman
- Department of Medicine, University of Cincinnati College of Medicine, OH 45267-0563, USA.
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17
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Abstract
There is increasing evidence supporting the involvement of immune cells and mediators in the control of intestinal physiology. Cell coculture systems and epithelial cell lines have provided convenient model systems for the study of immunomodulation of epithelial function. Abundant cytokines and immune mediators have been shown to directly or indirectly alter epithelial transport of ions and macromolecules. Animal models of hypersensitivity have shown that luminal antigen challenge in the intestine of sensitized rats induces a rapid ion secretory response due to enhanced transepithelial transport of antigen. Transport of ions and macromolecules is highly regulated and an important component of host defense. Dysregulation of epithelial function may play a role in several intestinal disorders, such as inflammatory bowel diseases and food allergy.
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Affiliation(s)
- L C Yu
- Intestinal Disease Research Program, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario L6J3X6, Canada
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18
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Schwiehert EM, Rozmahel R. Chapter 6 The cystic fibrosis transmembrane conductance regulator in the gastrointestinal system. CURRENT TOPICS IN MEMBRANES 2000. [DOI: 10.1016/s1063-5823(00)50008-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Abstract
Mast cells are found in the brain of many species. Although a considerable body of information is available concerning the development and differentiation of peripheral mast cells, little is known about brain mast cells. In the present study, the ontogeny of mast cells in the dove brain was followed by using three markers: acidic toluidine blue, alcian blue/safranin, and an antiserum to gonadotropin-releasing hormone (GnRH). Mast cells first appear in the pia on embryonic day (E)13-14 in ovo, then along blood vessels extending from the pia into the telencephalon on posthatch day 4-5, and in the medial habenula at week 3. Medial habenular mast cell numbers increase during development, peaking in peripubertal birds, and declining thereafter. Several measures indicate that mast cells mature within the medial habenula: there is an increase in the intensity of metachromasia, a switch from alcian blue granules in young animals to mixed alcian blue and safranin granules in older animals, and an increase in GnRH-like immunoreactivity. These results were extended by using electron microscopy. The architecture of mast cell granules evolved from electron lucent with small electron dense deposits at E15 to more electron dense granules with complex patterns of internal structure by 2 months. Ultrastructural immunocytochemistry for the GnRH-like peptide at 1 month revealed both immunopositive and negative cells, suggesting that the acquisition of this phenotype is not simultaneous across the population. Thus, immature mast cells infiltrate the central nervous system and undergo in situ differentiation within the neuropil.
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Affiliation(s)
- X Zhuang
- Department of Psychology, Columbia University, New York, New York 10027, USA
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20
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Abstract
Using a tissue culture model developed to study interactions between peripheral neurons and mast cells (MC), time-lapse microscopy showed that RBL-2H3 cells (a model of the mucosal MC) formed attachments with sympathetic neurons, ceased to divide, and moved along neurites toward the cell bodies. Electron microscopy showed significant increase in granules compared to intrinsic controls (RBL cells in coculture but lacking neurite contact). In studies using cohort cultures of 12- to 14-day-old sympathetic neurons, RBL cells adhered more rapidly to neurons than did control YB2/0 cells (a neutral target cell), and were inhibited in growth compared with RBL cells cultured in parallel without neurons. RBL cells cocultured with neurons for 24-48 h took up significantly more 3H-5HT and released a significantly larger percentage of 3H-5HT in response to the calcium ionophore A23187 than RBL cells in parallel pure cultures. Since no change in MC phenotype was seen, we conclude that contact with nerve membrane may be a developmental cue leading to maturation of MC.
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Affiliation(s)
- M G Blennerhassett
- Intestinal Diseases Research Programme and Department of Pathology, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada
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21
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Argenzio RA. Neuro-immune pathobiology of infectious enteric disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1997; 412:21-9. [PMID: 9191986 DOI: 10.1007/978-1-4899-1828-4_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent knowledge of neuro-endocrine-immune communication in the intestinal mucosa has provided a new paradigm for the pathophysiology of diarrheal disease that will significantly alter and advance therapeutic strategies. Mast cells, enteroendocrine cells and phagocytes are the proximate mediators of signalling cascades activated by parasitic nematodes and food allergens, enterotoxigenic bacteria, and at least some of the invasive pathogens, respectively. These proximate, trigger cells give rise to products that affect epithelial function directly, or indirectly through stimulation of prostaglandin production by mesenchymal cells, and enteric nerve stimulation, which can markedly amplify the initial stimulus. The enteric nervous system in fact may mediate the majority of the secretory response induced by enterotoxins or phagocytes. The signalling network mediated by cells in the lamina propria provides new points of control for pharmacological therapy.
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Affiliation(s)
- R A Argenzio
- College of Veterinary Medicine, North Carolina State University, Raleigh, USA
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22
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Keränen U, Järvinen H, Kärkkäinen P, Kiviluoto T, Kivilaakso E, Soinila S. Substance P--an underlying factor for pouchitis? Prospective study of substance P- and vasoactive intestinal polypeptide-immunoreactive innervation and mast cells. Dig Dis Sci 1996; 41:1665-71. [PMID: 8769299 DOI: 10.1007/bf02087922] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recent studies suggest that substance P (SP), vasoactive intestinal polypeptide (VIP), and mast cells play a role in inflammatory processes of the bowel. The aim of this study was to evaluate the distribution of SP and VIP immunoreactivities and to count mast cells in the ileal pouch of patients, who had pouchitis after restorative proctocolectomy performed for treatment of ulcerative colitis (UC), and to compare the findings in the same patients after a follow-up period. Nine patients with pouchitis underwent clinical evaluation, endoscopy of the pouch, and histological examination, which were repeated after the follow-up period of 14 months on average. The number and intensity of SP- and VIP-immunoreactive nerve fibers were visualized by immunofluorescence microscopy and subjected to quantitative scoring, and the number of mast cells per unit area was counted. The results were compared to the histological findings and the clinical status. Lamina propria contained fibers showing bright immunofluorescence for SP and VIP. The mean fluorescence intensity score of SP-immunoreactive nerve fibers in the lamina propria remained similar after the follow-up period (2.99 +/- 0.79 and 2.06 +/- 0.82, NS). SP-immunoreactive innervation correlated with the grade of acute (R2 = 0.5396, P = 0.0242) and chronic inflammation (R2 = 0.4561, P = 0.0459), while SP and VIP immunoreactivity, mast cell count, and histological changes did not correlate with the clinical status. The present study demonstrates an increase in the density of SP-immunoreactive nerve fibers in inflamed ileal pouch mucosa of clinically asymptomatic pouchitis patients. These results raise the possibility of therapeutic interference of SP-related processes in treatment of pouchitis.
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Affiliation(s)
- U Keränen
- Second Department of Surgery, University Central Hospital, Helsinki, Finland
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23
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Masson SD, McKay DM, Stead RH, Agro A, Stanisz A, Perdue MH. Nippostrongylus brasiliensis infection evokes neuronal abnormalities and alterations in neurally regulated electrolyte transport in rat jejunum. Parasitology 1996; 113 ( Pt 2):173-82. [PMID: 8760316 DOI: 10.1017/s0031182000066415] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Neuronal abnormalities have been described in the intestine of helminth-infected rats. However, the physiological ramifications of these changes have not been determined. Here, we examined epithelial ion secretion, indicated by increases in short-circuit current (Isc), evoked by electrical transmural stimulation (TS) of enteric nerves in Ussing-chambered jejunal tissues from Nippostrongylus brasiliensis-infected rats. Rats were examined at 10 and 35 days post-infection (p.i.); non-infected rats served as controls. TS resulted in significantly reduced ion secretion in jejunum from 10 day p.i. rats compared to controls or jejunum from 35 day p.i. rats. The TS response in tissue from infected rats had, unlike controls, no cholinergic component. Tissues from both non-infected and infected rats were equally responsive to the muscarinic agonist bethanechol, suggesting that the cholinergic defect was neuronal and not an inability of the epithelium to respond to cholinergic stimulation. However, increases in Isc evoked by exogenous substance P (SP) in tissue from rats 10 day p.i. were reduced in magnitude to approximately 25% of control values. Concomitant with these physiological changes, tissue from infected rats contained increased amounts of substance P immunoreactivity and intestinal sections displayed increased numbers of substance P-immunoreactive nerve fibre profiles at both 10 and 35 days p.i. Thus, following N. brasiliensis infection there is a shift in the enteric nervous system away from cholinergic to non-cholinergic regulation, associated with increased amounts of the pro-inflammatory neuropeptide, substance P. We speculate that changes in neuronal structure and function are intimately involved in the co-ordinated multicellular response to intestinal parasitic infection and subsequent gut recovery.
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Affiliation(s)
- S D Masson
- Department of Pathology, McMaster University, Hamilton, Ontario, Canada
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24
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Barclay RL, Dinda PK, Morris GP, Paterson WG. Morphological evidence of mast cell degranulation in an animal model of acid-induced esophageal mucosal injury. Dig Dis Sci 1995; 40:1651-8. [PMID: 7648964 DOI: 10.1007/bf02212685] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In previous studies we have demonstrated that microvascular permeability increases early in the course of experimental acid-induced esophageal mucosal injury. This is associated with an increase in the intraluminal appearance of histamine, suggesting a possible role for mast cells in this form of injury. In the present study, quantitative analysis of esophageal mast cells was undertaken using both light and electron microscopy in opossums undergoing intraluminal esophageal acid perfusion or normal saline control perfusion. Light microscopy showed that animals perfused with either 50 or 100 mM hydrochloric acid had an approximate 50% decrease in the number of stainable esophageal mast cells. Stereologic analysis of electron micrographs revealed that within the mucosa, the mean area of the mast cells as well as nuclear area and area of intact granules were also significantly reduced in acid perfused animals. Taken together these quantitative morphological analyses suggest that intraluminal acid exposure is associated with degranulation and/or lysis of esophageal mast cells and that released mediators from esophageal mast cells may play a role in the pathophysiology of reflux esophagitis.
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Affiliation(s)
- R L Barclay
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
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25
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McKay DM, Benjamin M, Baca-Estrada M, D'Inca R, Croitoru K, Perdue MH. Role of T lymphocytes in secretory response to an enteric nematode parasite. Studies in athymic rats. Dig Dis Sci 1995; 40:331-7. [PMID: 7851198 DOI: 10.1007/bf02065418] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Athymic (nude) rats have been used to assess the role of thymus-dependent T cells in the control of the intestinal response following infection with the enteric parasite, Nippostrongylus brasiliensis. Tissues from infected rats were excised on days 4, 7, 10, and 21 postinfection (p-i) for physiological and morphological studies; uninfected (day 0) rats served as controls. In response to the worm burden, jejunal tissues displayed a secretory response, indicated by an elevated baseline short-circuit current (Isc) on days 7 and 10 p-i, and were more responsive to histamine than control tissues. Despite this enhanced secretory response, approximately 35% of the worm burden was still present on day 21 p-i (compared with expulsion of > 95% by day 14 p-i in normal rats). Mast cell activation and hyperplasia, increased goblet cell (implying increased mucus synthesis) and intraepithelial leukocyte numbers, and abnormalities in Isc responses after electrical stimulation of enteric nerves were identified following infection. These events in nude rats were attenuated or delayed in onset as compared with conventional immunocompetent rats. Our results support the postulate that thymus-dependent T cells regulate the timing and/or nature of the mucosal response to enteric parasitic infections. However, ion secretion was not altered in the absence of T cells and, therefore, is more likely to be a consequence of mast cell activation.
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Affiliation(s)
- D M McKay
- Department of Pathology, McMaster University, Hamilton, Ontario, Canada
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26
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MacNaughton WK, Leach KE, Prud'homme-Lalonde L, Ho W, Sharkey KA. Ionizing radiation reduces neurally evoked electrolyte transport in rat ileum through a mast cell-dependent mechanism. Gastroenterology 1994; 106:324-35. [PMID: 7507872 DOI: 10.1016/0016-5085(94)90589-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND/AIMS Mechanisms of neuroimmune regulation of intestinal electrolyte transport under pathophysiological conditions are unclear. This study investigated the effect of ionizing radiation on ileal electrolyte transport. METHODS Rats were exposed to 10 Gy gamma-radiation and were killed 2, 24, and 48 hours later. Ileal segments were either mounted in Ussing chambers and exposed to electrical field stimulation, prostaglandin E2, leukotriene D4, or theophylline, or they were assayed for biochemical indices of inflammation. Other segments were processed for routine histological screening, mast cell counts, or immunohistochemical analysis of the distribution of vasoactive intestinal polypeptide or substance P immunoreactivity. RESULTS Basal short-circuit current was unchanged 2, 24, or 48 hours postirradiation. However, there was a reduction of tissue responsiveness to electrical field stimulation, prostaglandin E2, and theophylline but not to leukotriene D4. Decreased responsiveness at 2-hours postirradiation was blocked by pretreatment with the H1 antagonist pyrilamine. Tissue myeloperoxidase activity and 5-hydroxytryptamine content were not altered postirradiation, but tissue histamine and mucosal mast cells were significantly reduced at 24 and 48 hours. There were no significant changes in villus-crypt architecture until 48 hours postirradiation. There was no significant alteration in the distribution of immunoreactive vasoactive intestinal polypeptide or substance P. CONCLUSIONS Ionizing radiation reduced the transport response to neural stimulation. The effect correlated temporally with decreased mast cells and histamine, suggesting a functional role for previously reported mast cell-nerve interactions.
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Affiliation(s)
- W K MacNaughton
- Department of National Defense, University of Ottawa, Ontario, Canada
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27
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Jodal M, Wingren U, Jansson M, Heidemann M, Lundgren O. Nerve involvement in fluid transport in the inflamed rat jejunum. Gut 1993; 34:1526-30. [PMID: 8244137 PMCID: PMC1374415 DOI: 10.1136/gut.34.11.1526] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Net fluid transport was measured in denervated jejunal segments of rats infected with larvae of Nippostrongylus brasiliensis. On days 6-9 after nematode inoculation, when the jejunal segment exhibited macroscopic and microscopic signs of inflammation, net fluid absorption was noticeably attenuated compared with control, and in eight of 26 experiments a net fluid secretion was seen. To determine whether enteric nerves participated in the response, intravenous hexamethonium (10 mg/kg body weight) was given or lidocaine (1% solution) was placed on the serosa of the intestinal segment. Both drugs significantly reduced fluid secretion or increased fluid absorption. The effect was more pronounced the lower the rate of fluid absorption or the higher the rate of fluid secretion. The inflammatory response influenced intestinal fluid transport partly via activation of the enteric nervous system. It was estimated that 50-60% of the change in fluid transport caused by the parasite could be ascribed to activation of intramural nervous reflexes. The effect of hexamethonium indicates that a cholinergic synapse is present in the secretory nervous reflux activated by inflammation. Experiments were also performed on animals on days 11-14 after infection when the nematodes had been expelled from the animal. A large net fluid absorption was then recorded.
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Affiliation(s)
- M Jodal
- Department of Physiology, University of Göteborg, Sweden
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28
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McKay DM, Perdue MH. Intestinal epithelial function: the case for immunophysiological regulation. Implications for disease (2). Dig Dis Sci 1993; 38:1735-45. [PMID: 8359088 DOI: 10.1007/bf01303185] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Substantial amounts of data have been reported showing a role for immunomodulation of epithelial function (particularly ion secretion and permeability) using animal models of anaphylactic reactions. In part one of this review we outlined the main immune cell types and mediators/cytokines that are currently known to influence epithelial physiology either directly, or indirectly via an intermediate cell type. Here we will expand on the significance of these studies and show how antigenic activation of the mucosal immune system can evoke changes in epithelial function that may be beneficial to the host by mediating loss/inactivation of the antigen. However, a continued and inappropriate immune stimulation can lead to pathophysiological reactions and disease. Thus, we will present data on immune regulation of epithelial function with direct applicability to understanding the mechanism underlying human intestinal inflammatory and secretory disease. Finally, we highlight key strategic points in the cascade of immune events that can control epithelial function and thus may be of relevance in the formulation of new therapeutic approaches to intestinal inflammation.
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Affiliation(s)
- D M McKay
- Department of Pathology, Faculty of Health Science, McMaster University, Hamilton, Ontario, Canada
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29
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Pothoulakis C, Karmeli F, Kelly CP, Eliakim R, Joshi MA, O'Keane CJ, Castagliuolo I, LaMont JT, Rachmilewitz D. Ketotifen inhibits Clostridium difficile toxin A-induced enteritis in rat ileum. Gastroenterology 1993; 105:701-7. [PMID: 8395445 DOI: 10.1016/0016-5085(93)90886-h] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Clostridium difficile toxin A is the principal mediator of inflammatory enterocolitis in experimental animals. The purpose of this study was to explore the effect of ketotifen, an anti-inflammatory drug, on toxin A-induced enterotoxicity in rat ileum. METHODS The effects of intragastric administration of ketotifen on secretion, mannitol permeability, histological damage, and mucosal levels of leukotriene B4, leukotriene C4, and platelet activating factor in toxin A-exposed rat ileal loops were measured in vivo. The effects of ketotifen on toxin A-mediated release of rat mast cell protease II (rat mucosa mast cell product) release were also measured in rat ileal explants in vitro. The effect of ketotifen on neutrophil migration in vitro was also evaluated. RESULTS Ketotifen pretreatment inhibited toxin A-associated intestinal secretion by 42.5% and mannitol permeability by 56.3% and reduced epithelial cell inflammation and necrosis. These effects were associated with reduced levels of leukotriene B4 by 65.8%, leukotriene C4 by 88.8%, platelet activating factor by 77.8%, and inhibition of rat mast cell protease II by 58.4%. In addition, pretreatment of neutrophils with ketotifen inhibited neutrophil migration in vitro. CONCLUSIONS The protective effect of ketotifen in this animal model was associated with significant inhibition of release of mast cells and neutrophil derived mediators, supporting their involvement in C. difficile enteritis.
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Affiliation(s)
- C Pothoulakis
- Section of Gastroenterology, University Hospital, Boston University School of Medicine, Massachusetts
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30
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Abstract
The intestinal mucosa contains a dense nerve network and many inflammatory cells, and these may interact through the exchange of regulatory molecules. Evidence suggests that intestinal mucosal mast cells are innervated, and it is known that the density of this cell type changes significantly in nematode-infected rats. Recent data indicates that rat jejunal mucosal nerves remodel after Nippostrongylus brasiliensis infection, with degenerative and regenerative phases during the acute and recovery stages of inflammation. Seven weeks postinfection there is a net increase in the density and number per villus of mucosal nerves. These changes suggest that mucosal nerves exhibit structural plasticity in inflamed tissues, which must impact on interactions between the enteric nervous system and other mucosal elements in disease.
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Affiliation(s)
- R H Stead
- Department of Pathology, McMaster University, Hamilton, Ontario, Canada
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31
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Abstract
Gastrointestinal symptoms occur in a large number of patients with food allergies. Immediate hypersensitivity mechanisms may give rise to the nausea, vomiting, abdominal pain, and diarrhea experienced by these patients. However, there are limited human data about the pathophysiological basis for these symptoms. Most of the available information comes from a variety of animal models. This article reviews the literature using models of intestinal food hypersensitivity, as well as human studies, that have contributed to our understanding of the pathophysiological mechanisms in gastrointestinal food hypersensitivity.
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Affiliation(s)
- S E Crowe
- Intestinal Disease Research Unit, McMaster University, Hamilton, Ontario, Canada
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32
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Miller MJ, Zhang XJ, Gu XA, Clark DA. Acute intestinal injury induced by acetic acid and casein: prevention by intraluminal misoprostol. Gastroenterology 1991; 101:22-30. [PMID: 1904379 DOI: 10.1016/0016-5085(91)90455-t] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Acute injury was established in anesthetized rabbits by intraluminal administration of acetic acid with and without bovine casein, into loops of distal small intestine. Damage was quantified after 45 minutes by the blood-to-lumen movement of 51Cr-labeled ethylenediaminetetraacetic acid (EDTA) and fluorescein isothiocyanate-tagged bovine serum albumin as well as luminal fluid histamine levels. The amount of titratable acetic acid used to lower the pH of the treatment solutions to pH 4.0 was increased by the addition of calcium gluconate. Luminal acetic acid caused a 19-fold increase in 51Cr-EDTA accumulation over saline controls; casein did not modify this effect. In saline controls, loop fluid histamine levels bordered on the limits of detection (1 ng/g) but were elevated 19-fold by acetic acid exposure and markedly increased (118-fold) by the combination of acid and casein. Intraluminal misoprostol (3 or 30 micrograms/mL), administered 30 minutes before acetic acid, significantly attenuated the increase in epithelial permeability (luminal 51Cr-EDTA, fluorescein isothiocyanate-bovine serum albumin accumulation) and histamine release (P less than 0.05). Diphenhydramine, alone or in combination with cimetidine, and indomethacin (5 mg/kg IV) were not protective. It is concluded that exposure of the epithelium to acetic acid promotes the transepithelial movement of casein leading to enhanced mast cell activation and mucosal injury. Damage to the epithelial barrier can be prevented by misoprostol.
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Affiliation(s)
- M J Miller
- Department of Pediatrics, Louisiana State University School of Medicine, New Orleans
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33
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Changes in distribution of Ia antigen on epithelium of the jejunum and ileum in rats infected with Nippostrongylus brasiliensis. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1990; 57:83-95. [PMID: 2394037 DOI: 10.1016/0090-1229(90)90024-k] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This study compared the tissue distribution and cellular expression of Ia antigen in jejunal and ileal epithelium at various stages of intestinal inflammation produced by infecting rats with the nematode parasite Nippostrongylus brasiliensis. Tissues were examined at Day 0 (control), Day 4 (early), Day 10 (acute), and Day 16 (recovering). Frozen sections were stained with the MRC OX-4 anti-Ia monoclonal antibody using an immunoperoxidase technique. Control jejunal sections demonstrated positive epithelial Ia expression mainly in the mid-regions of the villi. The stain appeared to be mostly intracellular in the supranuclear area; the basolateral membrane stained faintly. At Day 4, a greater percentage of the epithelial cells expressed Ia, including those at the tips of the villi. The Day 10 sections demonstrated no staining at all of villus enterocytes, but the crypt epithelium was Ia positive. At Day 16, the pattern of Ia expression was similar to that seen in the early infection. In the ileum, stain was present in enterocytes over most of the villus and crypt regions except in the villus-crypt junction and did not change significantly during infection. We conclude that the changes in the expression of Ia antigen by intestinal epithelium are local to the site of infection and probably occur as a consequence of the host's inflammatory response.
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34
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Turnberg LA. The small intestine: prospects for therapeutic approaches in secretory diarrhoeal diseases. SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. SUPPLEMENT 1990; 175:85-92. [PMID: 1700466 DOI: 10.3109/00365529009093131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In many diarrhoeal diseases the intestinal mucosa is stimulated to secrete salt and water. This occurs in diarrhoea as a result of several bacterial toxins, is associated with inflammation and release of inflammatory mediators, and, in many instances, occurs when a neural element is evident. An understanding of the basic underlying mechanisms of secretion could lead to improvements in therapy. Development of vaccines against cholera is showing promise, and a knowledge of the complex field of inflammatory mediators, many of which provoke secretion, provides a foundation for development of more specific and selective anti-inflammatory agents. A detailed understanding of the complicated intracellular second-messenger systems, which are switched on by externally perceived signals, and of the ion transport responses, which are responsible for secretion, may lead to the development of specific anti-diarrhoeal drugs. Meanwhile, the message that oral rehydration therapy for severe diarrhoea, including cholera, is successful, should continue to be widely promulgated and taken up.
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Affiliation(s)
- L A Turnberg
- University Dept. of Medicine, Hope Hospital, Salford, U.K
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