l-663536 and Colitis

Enteric glia activation has been reported to amplify intestinal inflammation via the enteroglial-specific S100B protein. This neurotrophin promotes macrophage recruitment in the mucosa, amplify colonic inflammation and interacts with toll-like receptors (TLR). Molecules inhibiting S100B-driven enteric activation might mitigate the course of ulcerative colitis (UC). This study aims to investigate the effects of palmitoylethanolammide (PEA), a drug able to counteract astroglial activation in the central nervous system, on intestinal inflammation, in humans and mice.. Mouse models of dextran sodium sulphate (DSS)-induced colitis, colonic biopsies deriving from UC patients and primary cultures of mouse and human enteric glial cells (EGC), have been used to assess the effects of PEA, alone or in the presence of specific PPARα or PPARγ antagonists, on: macroscopic signs of UC (DAI score, colon length, spleen weight, macrophages/neutrophils infiltration); the expression and release of proinflammatory markers typical of UC; TLR pathway in EGCs.. PEA treatment improves all macroscopic signs of UC and decreases the expression and release of all the proinflammatory markers tested. PEA anti-inflammatory effects are mediated by the selective targeting of the S100B/TLR4 axis on ECG, causing a downstream inhibition of nuclear factor kappa B (NF-kB)-dependent inflammation. Antagonists at PPARα, but not PPARγ, abolished PEA effects, in mice and in humans.. Because of its lack of toxicity, its ability in reducing inflammation and its selective PPARα action, PEA might be an innovative molecule to broaden pharmacological strategies against UC.

Topics: Amides; Anilides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cells, Cultured; Colitis; Colitis, Ulcerative; Colon, Sigmoid; Cyclooxygenase 2; Dextran Sulfate; Dinoprostone; Endocannabinoids; Ethanolamines; Female; Glial Fibrillary Acidic Protein; Humans; Indoles; Male; Mice; Middle Aged; Nerve Tissue Proteins; Neuroglia; Neutrophil Infiltration; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase Type II; Palmitic Acids; PPAR alpha; PPAR gamma; Rectum; S100 Calcium Binding Protein beta Subunit; Severity of Illness Index; Signal Transduction; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha

The pathophysiology of enterohaemorrhagic Escherichia coli (EHEC) infection remains unclear. Eicosanoids have been implicated as pathophysiological mediators in other colitides.. To determine if prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) contribute to mucosal inflammation and dysfunction in EHEC colitis.. Ten day old rabbits were infected with EHEC. For five days after infection, mucosal synthesis of PGE(2) and LTB(4) was measured in distal colonic tissue from control and infected animals and (51)Cr-EDTA permeability was assessed in vivo. Myeloperoxidase activity was measured and histological inflammation and damage were assessed at five days in control and infected animals and after treatment of infected animals with the LTB(4) synthesis inhibitor MK-886. In separate experiments, ion transport was measured in Ussing chambers, before and after in vitro addition of the cyclooxygenase inhibitor indomethacin.. LTB(4) synthesis was increased from day 2 after infection onwards and PGE(2) synthesis was increased on day 3. Mucosal permeability did not increase until day 5 after infection. MK-886 inhibited colonic LTB(4) production but did not reduce diarrhoea, inflammation, or mucosal damage. Electrolyte transport was not significantly altered on day 3 after infection. However, both Cl secretion and reduced Na absorption found on day 5 were partially reversed by indomethacin.. Tissue synthesis of PGE(2) and LTB(4) did not correlate temporally with EHEC induced inflammation or changes in mucosal permeability and ion transport. Cyclooxygenase inhibition partially reversed ion transport abnormalities but lipoxygenase inhibition did not affect mucosal inflammation or histological damage. We conclude that the contribution of eicosanoids to mucosal injury and dysfunction is more complex than previously suggested.

Topics: Animals; Colitis; Dinoprostone; Disease Models, Animal; Eicosanoids; Electrolytes; Escherichia coli Infections; Gastric Mucosa; Gastrointestinal Hemorrhage; Indoles; Leukotriene B4; Lipoxygenase Inhibitors; Permeability; Rabbits

We measured daily food intake and body weight in rats before and after the induction of colitis by intrarectal administration of either 2,4,6-trinitrobenzenesulfonic acid in ethyl alcohol (TNBE) or 4% acetic acid (AA). Administration of TNBE or AA induced inflammation in the distal colon, which was reflected by a significant increase in myeloperoxidase (MPO) activity in the colon. On days 1, 2, and 3 after induction of colitis by TNBE, food intake fell by 80, 70, and 50%, respectively, compared with pretreatment values; food intake returned to normal by day 4. Body weight fell within 24 h after induction of colitis and remained 10% less than control for at least 5 days. Colitis induced by AA produced a similar pattern and degree of decreased food intake and weight loss. Treatment with the 5'-lipoxygenase inhibitor MK-886 significantly reduced concentrations of leukotriene B4 in the colon of TNBE-treated rats but did not affect food intake. In contrast, the cyclooxygenase inhibitor indomethacin decreased prostaglandin E2 concentrations in the colon but also attenuated the suppression of feeding by 52 and 64% on the first 2 days after induction of colitis by TNBE. These results identify a specific prostaglandin-mediated suppression of feeding in the rat with acute colitis induced by TNBE and illustrate the utility of this model for studying mechanisms underlying anorexia associated with inflammation of the gastrointestinal tract.

Topics: Acetates; Acetic Acid; Administration, Rectal; Animals; Body Weight; Colitis; Eating; Indoles; Indomethacin; Male; Rats; Rats, Sprague-Dawley; Trinitrobenzenesulfonic Acid

The implication of leukotrienes as mediators of inflammation and recent evidence that prostaglandin analogues provide a beneficial effect during experimental colitis led to the speculation that (i) leukotrienes may be injurious and (ii) prostaglandins may be protective to colonic mucosa. Using a 2% acetic acid induced rat colitis model, we administered specific cyclooxygenase (indomethacin) and leukotriene biosynthesis inhibitors (MK-886) to examine the effect of endogenous prostaglandins and leukotrienes on colonic macroscopic injury, mucosal inflammation as measured by myeloperoxidase activity, net in vivo intestinal fluid absorption, and colonic PGE2 and LTB4 levels as measured by in vivo rectal dialysis. Indomethacin treatment prior to induction of colitis reduced endogenous mucosal PGE2 levels and exacerbated macroscopic ulceration and net fluid absorption. Addition of the exogenous PGE1 analogue misoprostol to the indomethacin-exacerbated colitis completely healed colonic macroscopic ulceration and inflammation but only partially improved fluid absorptive injury. The specific leukotriene biosynthesis inhibitor MK-886 administered prior to induction of colitis healed macroscopic ulceration and inflammation but not fluid absorptive injury. This mucosal reparative effect of MK-886 occurred at a dose that reduced colonic LTB4 synthesis while concomitantly enhancing PGE2 levels. Combining MK-886 with misoprostol treatment improved not only macroscopic ulceration and inflammation but also provided a synergistic effect that maintained net colonic fluid absorption at noncolitic control levels. These studies suggest that, during the induction of experimental colitis, endogenous prostaglandins play a pivotal role in providing a mucosal healing effect, and that leukotriene biosynthesis inhibitor may manifest part of its beneficial effect by shifting arachidonic acid metabolism towards production of prostaglandins.

Topics: Acetates; Animals; Body Fluids; Colitis; Dialysis; Dinoprostone; Indoles; Indomethacin; Intestinal Mucosa; Leukotriene Antagonists; Leukotriene B4; Male; Misoprostol; Peroxidase; Rats; Rats, Sprague-Dawley