vasoactive-intestinal-peptide and Ileitis

Glucagon-like peptide-2 (GLP-2) is an important regulator of nutritional absorptive capacity with anti-inflammatory actions. We hypothesized that GLP-2 reduces intestinal mucosal inflammation by activation of vasoactive intestinal polypeptide (VIP) neurons of the submucosal plexus. Ileitis or colitis was induced in rats by injection of trinitrobenzene sulfonic acid (TNBS), or colitis was induced by administration of dextran sodium sulfate (DSS) in drinking water. Subsets of animals received (1-33)-GLP-2 (50 mug/kg sc bid) either immediately or 2 days after the establishment of inflammation and were followed for 3-5 days. The involvement of VIP neurons was assessed by concomitant administration of GLP-2 and the VIP antagonist [Lys(1)-Pro(2,5)-Arg(3,4)-Tyr(6)]VIP and by immunohistochemical labeling of GLP-2-activated neurons. In all models, GLP-2 treatment, whether given immediately or delayed until inflammation was established, resulted in significant improvements in animal weights, mucosal inflammation indices (myeloperoxidase levels, histological mucosal scores), and reduced levels of inflammatory cytokines (IFN-gamma, TNF-alpha, IL-1beta) and inducible nitric oxide synthase, with increased levels of IL-10 in TNBS ileitis and DSS colitis. Reduced rates of crypt cell proliferation and of apoptosis within crypts in inflamed tissues were also noted with GLP-2 treatment. These effects were abolished with coadministration of GLP-2 and the VIP antagonist. GLP-2 was shown to activate neurons and to increase the number of cells expressing VIP in the submucosal plexus of the ileum. These findings suggest that GLP-2 acts as an anti-inflammatory agent through activation of enteric VIP neurons, independent of proliferative effects. They support further studies to examine the role of neural signaling in the regulation of intestinal inflammation.

Topics: Animals; Anti-Inflammatory Agents; Colitis, Ulcerative; Dextran Sulfate; Disease Models, Animal; Enteric Nervous System; Glucagon-Like Peptide 2; Ileitis; Male; Neurotensin; Rats; Rats, Sprague-Dawley; Recombinant Fusion Proteins; Trinitrobenzenesulfonic Acid; Vasoactive Intestinal Peptide

Properties of enteric neurons are transformed by inflammation and protein kinase C (PKC) isoforms are involved both in long-term changes in enteric neurons, and in transducing the effects of substances released during inflammation. We investigated roles of PKCepsilon in submucosal neurons by studying translocation in response to inflammatory mediators, effects on neuron excitability, and the changes in PKCepsilon distribution in a trinitrobenzene sulphonate model of ileitis.. Immunohistochemical detection and analysis of association with membrane and cytosolic fractions, and Western blot analysis of cytosolic and particulate fractions were used to quantify translocation. Electrophysiology methods were used to measure effects on neuron excitability.. All submucosal neurons were immunoreactive for the novel PKC, PKCepsilon, and direct PKC activators, phorbol 12,13-dibutyrate, ingenol 3,20-dibenzoate, and the PKCepsilon-specific activator, transactivator of transduction-Psiepsilon receptor for activated C kinase, all caused PKCepsilon translocation from cytoplasm to surfaces of the neurons. Electrophysiologic studies showed that the stimulant of novel PKCs, ingenol (1 micromol/L), increased excitability of all neurons. Stimulation of protease-activated receptors caused PKCepsilon translocation selectively in vasoactive intestinal peptide secretomotor neurons, whereas a neurokinin 3 tachykinin receptor agonist caused translocation in neuropeptide Y and calretinin neurons. In all cases translocation was reduced significantly by a PKCepsilon-specific translocation inhibitor peptide. Increased PKCepsilon at the plasma membrane occurred in all neurons 6-7 days after an inflammatory stimulus.. Major targets for PKCepsilon include ion channels near the plasma membrane. PKCepsilon is likely to have a significant role in controlling the excitability of submucosal neurons and is probably an intermediate in causing hyperexcitability after inflammation.

Topics: Action Potentials; Animals; Blotting, Western; Calbindin 2; Cell Membrane; Cytoplasm; Disease Models, Animal; Diterpenes; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Activators; Guinea Pigs; Ileitis; Ileum; In Vitro Techniques; Inflammation Mediators; Kinetics; Neuropeptide Y; Oligopeptides; Peptide Fragments; Phorbol 12,13-Dibutyrate; Protein Kinase C-epsilon; Protein Transport; Receptor, PAR-2; Receptors, Neurokinin-3; S100 Calcium Binding Protein G; Signal Transduction; Submucous Plexus; Substance P; Trinitrobenzenesulfonic Acid; Trypsin; Vasoactive Intestinal Peptide

In the present study the ELISA test was used to investigate the influence of chemically-induced ileitis on the dorsal root ganglia (DRG) neurons in the pig. The preliminary retrograde fluorescent tracing study revealed that ileum-projecting sensory neurones (IPN) are located in the thoracic ganglia (Th; Th8-Th13). The ileum wall in experimental (E) pigs was subjected to multiple injection with 4% paraformaldehyde to induce inflammation, while in the control (C) animals the organ was injected with 0.1 M phosphate buffer. Three days later the DRGs (Th8-Th13) collected from all the animals were evaluated for VIP, SP, CGRP, NPY, GAL and SOM content with an ELISA test. It was found that the inflammation increased clearly the tissue level of SP, GAL and SOM.

Topics: Animals; Calcitonin Gene-Related Peptide; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Dyes; Formaldehyde; Galanin; Ganglia, Spinal; Ileitis; Ileum; Neurons, Afferent; Neuropeptide Y; Neuropeptides; Polymers; Somatostatin; Substance P; Sus scrofa; Thoracic Vertebrae; Up-Regulation; Vasoactive Intestinal Peptide; Visceral Afferents

There have been conflicting results regarding the effect of Crohn's disease on the neurochemical composition of the enteric nervous system.. To examine the effect of Crohn's disease on the neurochemical composition of enteric nerve fibres and cell bodies using whole mount preparations of human ileum.. Whole wall ileum from seven normal subjects and nine patients with Crohn's disease was used to investigate the neurochemical composition of neurones and nerve fibres in the myenteric plexus, circular muscle, and serosa layer of ileum using immunohistochemical techniques.. Increased tyrosine hydroxylase, 5-hydroxytryptamine, and neuropeptide Y immunoreactivity was exclusively seen in the myenteric plexus. There was increased neurofilament immunoreactivity in the myenteric plexus and nerve fibres of the circular muscle layer, and thick bundles of immunoreactive nerve fibres in the serosa layer. Increased vasoactive intestinal polypeptide, nitric oxide synthase, and pituitary adenylate cyclase activating peptide immunoreactivity was seen in the myenteric plexus and nerve fibres of the circular muscle layer, and aggregates of inflammatory cells in the serosa layer of the afflicted segment of Crohn's ileum. In addition, there was a chaotic display of nerve fibres containing some of the neuroactive substances with a high frequency of enlarged varicosities in the myenteric ganglia and/or nerve fibres of the circular muscle layer of Crohn's ileum.. Results show quantitative as well as qualitative changes in the neurochemical composition of enteric nerve fibres and nerve cell bodies of Crohn's ileum. These changes and the presence of nitric oxide synthase and peptides immunoreactive inflammatory cells in the serosa layer suggest that nerve-immune interactions may have a significant role in the process of the inflammatory changes seen in Crohn's ileitis.

Topics: Adult; Aged; Crohn Disease; Enteric Nervous System; Fluorescent Antibody Technique, Indirect; Humans; Ileitis; Ileum; Image Processing, Computer-Assisted; Middle Aged; Neuropeptide Y; Neuropeptides; Neurotransmitter Agents; Nitric Oxide Synthase; Pituitary Adenylate Cyclase-Activating Polypeptide; Serotonin; Tyrosine 3-Monooxygenase; Vasoactive Intestinal Peptide

After colectomy, continent ileal reservoirs are an accepted alternative to conventional ileostomy for patients with ulcerative colitis. To assess the effect of these reservoirs on digestive function, circulating and morphologic gut endocrine responses were measured in patients with a continent ileostomy or with a pelvic pouch and compared to patients with conventional ileostomy, with active ulcerative colitis and healthy controls. Eight subjects were studied in each group. Basal and postprandial plasma gastrin, enteroglucagon, neurotensin, vasoactive intestinal polypeptide, insulin, pancreatic glucagon, and pancreatic polypeptide in both groups with ileal reservoirs were equivalent to controls. Basal plasma motilin and postprandial plasma gastric inhibitory polypeptide were raised in ileal reservoir patients, but similar changes also occurred in ulcerative colitis patients and those with conventional ileostomy. In one half of patients, cell populations of enteroglucagon, peptide YY, and neurotensin were decreased in pouch mucosa that corresponded with the presence of mucosal inflammation. On the other hand, with pouch inflammation vasoactive intestinal polypeptide immunoreactive nerves were increased and a proportion of the fibres were moderately coarsened. Mucosal concentrations of vasoactive intestinal polypeptide did not, however, exceed that of controls. After an ileal reservoir sufficient reserve remains for gut hormone release into the circulation, suggesting compensation for the presence of a reservoir and the absence of a colon; circulating hormone changes do occur but are consequent upon previous ulcerative colitis. Reservoirs may show neuromorphologic alterations that appear to be related to mucosal inflammation.

Topics: Adult; Colitis, Ulcerative; Eating; Female; Gastrointestinal Hormones; Humans; Ileitis; Ileostomy; Ileum; Male; Middle Aged; Neurotensin; Pancreatic Hormones; Postoperative Complications; Vasoactive Intestinal Peptide