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Colon Mucosa (colon + mucosa)
Selected AbstractsThe regulation of veratridine-stimulated electrogenic ion transport in mouse colon by neuropeptide Y (NPY), Y1 and Y2 receptorsBRITISH JOURNAL OF PHARMACOLOGY, Issue 5 2005Niall P Hyland Neuropeptide Y (NPY) is a prominent enteric neuropeptide with prolonged antisecretory effects in mammalian intestine. Veratridine depolarises neurons consequently causing epithelial anion secretion across mouse colon mucosa. Our aim was to characterise functionally, veratridine-stimulated mucosal responses and to determine the roles for NPY, Y1, and Y2 receptors in modulating these neurogenic effects. Colon mucosae (with intact submucous innervation) from wild-type mice (+/+) and knockouts lacking either NPY (NPY,/,), Y1,/, or Y2,/, were placed in Ussing chambers and voltage clamped at 0 mV. Veratridine-stimulated short-circuit current (Isc) responses in +/+, Y1 or Y2 antagonist pretreated +/+ colon, Y1,/, and NPY,/, colon were insensitive to cholinergic blockade by atropine (At; 1 ,M) and hexamethonium (Hex; 10 ,M). Tetrodotoxin (TTX, 100 nM) abolished veratridine responses, but had no effect upon carbachol (CCh) or vasoactive intestinal polypeptide (VIP)-induced secretory responses. To establish the functional roles for Y1 and Y2 receptors, +/+ tissues were pretreated with either the Y1 or Y2 receptor antagonist (BIBO3304 (300 nM) or BIIE0246 (1 ,M), respectively) and veratridine responses were compared with those from Y1,/, or Y2,/, colon. Neither BIBO3304 nor Y1,/, altered veratridine-induced secretion, but Y1 agonist responses were abolished in both preparations. In contrast, the Y2 antagonist BIIE0246 significantly amplified veratridine responses in +/+ mucosa. Unexpectedly, NPY,/, colon exhibited significantly attenuated veratridine responses (between 1 and 5 min). We demonstrate that electrogenic veratridine responses in mouse colon are noncholinergic and that NPY can act directly upon epithelia, a Y1 receptor effect. The enhanced veratridine response observed in +/+ tissue following BIIE0246, indicates that Y2 receptors are located on submucosal neurons and that their activation by NPY will inhibit enteric noncholinergic secretory neurotransmission. We also demonstrate Y1 and Y2 receptor-mediated antisecretory tone in +/+ colon and show selective loss of each in Y1 and Y2 null colon respectively. In NPY,/, tissue, only Y1 -mediated tone was present, this presumably being mediated by endogenous endocrine peptide YY. Y2 tone was absent from NPY,/, (and Y2,/,) colon and we conclude that NPY activation of neuronal Y2 receptors attenuates secretory neurotransmission thereby providing an absorptive electrolyte tone in isolated colon. British Journal of Pharmacology (2005) 146, 712,722. doi:10.1038/sj.bjp.0706368 [source] MAGNIFYING COLONOSCOPY FOR THE DIAGNOSIS OF INFLAMMATORY CHANGES IN ULCERATIVE COLITISDIGESTIVE ENDOSCOPY, Issue 3 2006Satoshi Sugano Background:, Endoscopic observation is the most effective method for the evaluation of staging in ulcerative colitis (UC). However, in cases with very mild inflammatory activity, histopathological diagnosis may also be required. Unfortunately, biopsy-related accidents are not uncommon. As an alternative, we have used a magnifying colonoscope commonly used for tumor diagnosis to examine in detail the colon mucosa of UC patients in clinical remission, and then compared these findings relative to conventional endoscopy using histopathological diagnosis. Subjects and Methods:, Among UC cases examined by colonoscopy between April 2000 and April 2005, 27 cases without hematochezia for at least 1 month were enrolled in this study. Following observations of inflammatory changes using conventional colonoscopy, magnifying observation and biopsies at a total of 144 sites were evaluated. Using histopathological standards, acute-phase inflammation was indicated by the presence of neutrophil infiltration, whereas chronic-phase inflammation was indicated by infiltration of lymphocytes, plasma cells and eosinophils. Results:, Indicators of significant inflammation by conventional observation was erosion. Under magnification, inflammation appears as superficial defects in mucosa and small whitish spots. When the presence of infiltrating neutrophils was used as a positive histological marker for inflammation, there was no difference in the accuracy of diagnosis by conventional observation (95.1%) versus magnifying observation (97.2%). In contrast, when lymphocyte infiltration was used as a marker, the accuracy of diagnosis increased significantly (88.2%) using magnifying observation relative to conventional observation (61.1%). Conclusions:, Magnifying endoscopy can be used effectively in the evaluation of minute mucosal changes in cases of UC remission. [source] Protective effect of curcumin, a Curcuma longa constituent, in early colonic inflammation in rats,DRUG DEVELOPMENT RESEARCH, Issue 6 2009Juan Manuel Sánchez-Calvo Abstract Curcumin, a polyphenol derived from the plant, Curcuma longa, has a variety of pharmacological effects, including chemotherapeutic, anti-inflammatory, antiangiogenic, and antioxidant activities. To gain a better understanding of the effects and mechanisms of action of curcumin on the acute injury caused by intra-colonic administration of acetic acid (AA) in rats, inflammation was assessed by histology and myeloperoxidase activity (MPO; an index of neutrophil infiltration in the mucosa); Th1 and Th2 cytokine production; histological and histochemical analysis of the lesions; nitrite production in colon mucosa; and the expression of iNOS, COX-1 and -2 using Western blotting and inmmunohistochemistry. We also studied the involvement of the p38 MAPK/JNK signalling pathway in the protective effect of curcumin in acute colonic inflammation. Curcumin (50,100,mg/kg/day) reduced the degree of colonic injury, the index of neutrophil infiltration and Th1 cytokine secretion, and increased IL-10 production, reduced colonic levels of nitrites, and reduced COX-2 and iNOS overexpression. A reduction in the activation of p38 and JNK MAPKs was also observed. Thus, we show that the widely used food additive, curcumin reduced the development of AA-induced colitis and alleviated the inflammatory response. Inhibition of MAPK signalling by curcumin could explain the changes on the cytokine Th1/Th2 profile, the reduction of COX-2 and iNOS signaling, as well as the decreased nitrite production in colonic mucosa, suggesting that curcumin may be useful in the treatment of ulcerative colitis. Drug Dev Res, 2009. © 2009 Wiley-Liss, Inc. [source] Plant sterol guggulsterone inhibits nuclear factor-,B signaling in intestinal epithelial cells by blocking I,B kinase and ameliorates acute murine colitisINFLAMMATORY BOWEL DISEASES, Issue 12 2006Jae Hee Cheon MD Abstract Background/Aims: The plant sterol guggulsterone has been shown to have anti-inflammatory properties. It remains unknown, however, whether guggulsterone is effective for the treatment of inflammatory bowel disease (IBD). Therefore, we investigated anti-inflammatory effects of guggulsterone on intestinal epithelial cells (IEC) and on experimental murine colitis models and elucidated its molecular mechanisms. Methods: Human Caco-2 cells and rat non-transformed IEC-18 cells were stimulated with interleukin (IL)-1, or lipopolysaccharide (LPS) with or without guggulsterone. The effects of guggulsterone on nuclear factor (NF)-,B signaling in IEC were examined by intercellular adhesion molecule (ICAM)-1 real-time reverse-transcription polymerase chain reaction, NF-,B transcriptional activity assay, Western blotting for I,B phosphorylation/degradation, electrophoretic mobility shift assay, and in vitro I,B kinase (IKK) assay. For in vivo study, dextran sulfate sodium (DSS)-treated mice were fed with or without guggulsterone. Colitis was quantified by disease activity index and evaluation of macroscopic and microscopic findings. Phosphorylation of I,B and IKK in colon mucosa was assessed by Western blotting and immunohistochemistry. Results: Guggulsterone significantly inhibited LPS- or IL-1,-induced ICAM-1 gene expression, NF-,B transcriptional activity, I,B phosphorylation/degradation, and NF-,B DNA binding activity in IEC. Moreover, guggulsterone strongly blocked IKK activity. Administration of guggulsterone significantly reduced the severity of DSS-induced murine colitis as assessed by clinical disease activity score, colon length, and histology. Furthermore, tissue upregulation of I,B and IKK phosphorylation induced by DSS was attenuated in guggulsterone-treated mice. Conclusion: Guggulsterone blocks NF-,B signaling pathway by targeting IKK complex in IEC and attenuates DSS-induced acute murine colitis, which suggests that guggulsterone could be an attractive therapeutic option in the treatment of IBD. [source] Frequent inactivation of SPARC by promoter hypermethylation in colon cancersINTERNATIONAL JOURNAL OF CANCER, Issue 3 2007Eungi Yang Abstract Epigenetic modification of gene expression plays an important role in the development of human cancers. The inactivation of SPARC through CpG island methylation was studied in colon cancers using oligonucleotide microarray analysis and methylation specific PCR (MSP). Gene expression of 7 colon cancer cell lines was evaluated before and after treatment with the demethylating agent 5-aza-2,-deoxycytidine (5Aza-dC) by oligonucleotide microarray analysis. Expression of SPARC was further examined in colon cancer cell lines and primary colorectal cancers, and the methylation status of the SPARC promoter was determined by MSP. SPARC expression was undetectable in 5 of 7 (71%) colorectal cancer cell lines. Induction of SPARC was demonstrated after treatment with the demethylating agent 5Aza-dC in 5 of the 7 cell lines. We examined the methylation status of the CpG island of SPARC in 7 colon cancer cell lines and in 20 test set of colon cancer tissues. MSP demonstrated hypermethylation of the CpG island of SPARC in 6 of 7 cell lines and in all 20 primary colon cancers, when compared with only 3 of 20 normal colon mucosa. Immunohistochemical analysis showed that SPARC expression was downregulated or absent in 17 of 20 colon cancers. A survival analysis of 292 validation set of colorectal carcinoma patients revealed a poorer prognosis for patients lacking SPARC expression than for patients with normal SPARC expression (56.79% vs. 75.83% 5-year survival rate, p = 0.0014). The results indicate that epigenetic gene silencing of SPARC is frequent in colon cancers, and that inactivation of SPARC is related to rapid progression of colon cancers. © 2007 Wiley-Liss, Inc. [source] Influence of methylated p15 INK4b and p16 INK4a genes on clinicopathological features in colorectal cancerJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8 2006Atsushi Ishiguro Abstract Background and Aim:, Genetic silencing by promoter methylation has attracted attention in the carcinogenesis of colorectal cancer. Methylation of the p16INK4a gene has been found in primary colorectal cancer. Although the p15INK4b gene displays high homology to the p16INK4a gene in the amino acid sequence, methylation of p15INK4b has not been fully studied. We investigated p15INK4b methylation status in patients with colorectal cancer to verify the association between the methylation of p15INK4b and clinicopathological features compared with p16INK4a. Methods:, DNA samples from the tissues of primary colorectal cancer and corresponding adjacent normal colon mucosa were obtained from surgical resections of 88 patients (47 males and 41 females, aged 29,83 years). Methylation-specific polymerase chain reaction was used to analyze p15INK4b and p16INK4a methylation status after bisulfite modification. Cumulative survival rates (mean follow-up period: 53.2 months) were calculated by the Kaplan-Meier analysis. Results:, Methylations of p15INK4b and p16INK4a genes were detected in 23 (26.1%) and 20 (22.7%) colorectal cancers, respectively. Methylation of p15INK4b was not associated with any clinicopathological features. Compared with normal mucosa, the methylation of p15INK4b was more prominent in tumor tissue (P < 0.001). Reverse transcription-polymerase chain reaction (RT-PCR) revealed that p15INK4b methylaton decreased mRNA expression. Kaplan-Meier analysis showed that patients with stage I-II had a significant difference in survival rate between those with and without methylated p15INK4b (P = 0.018). Conclusions:, Our results suggest that methylation of the p15INK4b gene contributes to the process of carcinogenesis in colorectal cancer as well as p16INK4a and is useful as a prognostic factor in the early stage. [source] Effects of black radish root (Raphanus sativus L. var niger) on the colon mucosa in rats fed a fat rich dietPHYTOTHERAPY RESEARCH, Issue 7 2002P Sipos Abstract The effect of black radish root (Raphanus sativus L. var niger) was studied on the structure and redox state of the colon mucosa in fat-rich diet fed rats. The epithelial lining disrupted, the number of enterocytes and the goblet cells reduced and inflammatory cells were observed in rats fed with a fat-rich diet. After treatment with granules from black radish root all of the histopathological changes and parameters of the redox state caused by the fat-rich diet were improved. The structure of the epithelial cells was similar to the controls, the number of goblet cells increased and no inflammation was observed. Copyright © 2002 John Wiley & Sons, Ltd. [source] Reproducibility, sensitivity and compatibility of the ProteoExtract® subcellular fractionation kit with saturation labeling of laser microdissected tissuesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 16 2009Sonal Sawhney Abstract Laser microdissection (LMD), a method of isolating specific microscopic regions of interest from a tissue that has been sectioned, is increasingly being applied to study proteomics. LMD generally requires tissues to be fixed and histologically stained, which can interfere with protein recovery and subsequent analysis. We evaluated the compatibility and reproducibility of protein extractions from laser microdissected human colon mucosa using a subcellular fractionation kit (ProteoExtract®, Calbiochem). Four protein fractions corresponding to cytosol (fraction 1), membrane/organelle (fraction 2), nucleus (fraction 3) and cytoskeleton (fraction 4) were extracted, saturation labeled with Cy5 and 5,,g separated by both acidic (pH 4,7) and basic (pH 6,11) 2-DE. The histological stains and fixation required for LMD did not interfere with the accurate subcellular fractionation of proteins into their predicted fraction. The combination of subcellular fractionation and saturation CyDye labeling produced very well resolved, distinct protein spot maps by 2-DE for each of the subcellular fractions, and the total number of protein spots consistently resolved between three independent extractions for each fraction was 893, 1128, 1245 and 1577 for fractions 1, 2, 3 and 4, respectively. Although significant carryover of protein did occur between fractions, this carryover was consistent between experiments, and very low inter-experimental variation was observed. In summary, subcellular fractionation kits are very compatible with saturation labeling DIGE of LMD tissues and provide greater coverage of proteins from very small amounts of microdissected material. [source] Potential antioxidant activity of celecoxib and amtolmetin guacyl: in vitro studiesAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 1 2007M. Kirkova Summary 1,In vitro studies of the potential antioxidant activity of the selective cyclo-oxygenase-2 inhibitor celecoxib and the non-steroid anti-inflammatory drug amtolmetin guacyl (AMG) were carried out. The study included experiments on the ability of these drugs to affect some indices of the oxidative stress [lipid peroxidation (LP), activity of antioxidant enzymes, glutathione (GSH) level] in rat stomach and colon mucosa and in liver. 2,Celecoxib and AMG did not change the activity of the enzymes GSH-peroxidase, oxidased glutathione (GSSG)-reductase and glucose-6-phosphate-dehydrogenase, as well as the GSH level in all tissue preparations. An increased superoxide dismutase (SOD) activity and a tendency to a decreased Fe/ascorbic acid-induced LP in stomach and colon mucosa were found, but only in the presence of AMG. 3,In the liver, both celecoxib and AMG decreased spontaneous and Fe/ascorbic acid-induced LP. SOD activity was enhanced only in the presence of AMG. 4,Experiments aimed at studying celecoxib and AMG in free oxygen radical-generating systems were also carried out. AMG and tolmetin (the main metabolite of AMG) inhibited OH, -provoked deoxyribose degradation in a Fenton system. Celecoxib had no effect on free radicals when tested in the same system. 5,In conclusion, the results of the present in vitro studies suggest that AMG and celecoxib possess antioxidant and metal-chelating abilities, which might contribute to their beneficial effects. [source] The regulation of veratridine-stimulated electrogenic ion transport in mouse colon by neuropeptide Y (NPY), Y1 and Y2 receptorsBRITISH JOURNAL OF PHARMACOLOGY, Issue 5 2005Niall P Hyland Neuropeptide Y (NPY) is a prominent enteric neuropeptide with prolonged antisecretory effects in mammalian intestine. Veratridine depolarises neurons consequently causing epithelial anion secretion across mouse colon mucosa. Our aim was to characterise functionally, veratridine-stimulated mucosal responses and to determine the roles for NPY, Y1, and Y2 receptors in modulating these neurogenic effects. Colon mucosae (with intact submucous innervation) from wild-type mice (+/+) and knockouts lacking either NPY (NPY,/,), Y1,/, or Y2,/, were placed in Ussing chambers and voltage clamped at 0 mV. Veratridine-stimulated short-circuit current (Isc) responses in +/+, Y1 or Y2 antagonist pretreated +/+ colon, Y1,/, and NPY,/, colon were insensitive to cholinergic blockade by atropine (At; 1 ,M) and hexamethonium (Hex; 10 ,M). Tetrodotoxin (TTX, 100 nM) abolished veratridine responses, but had no effect upon carbachol (CCh) or vasoactive intestinal polypeptide (VIP)-induced secretory responses. To establish the functional roles for Y1 and Y2 receptors, +/+ tissues were pretreated with either the Y1 or Y2 receptor antagonist (BIBO3304 (300 nM) or BIIE0246 (1 ,M), respectively) and veratridine responses were compared with those from Y1,/, or Y2,/, colon. Neither BIBO3304 nor Y1,/, altered veratridine-induced secretion, but Y1 agonist responses were abolished in both preparations. In contrast, the Y2 antagonist BIIE0246 significantly amplified veratridine responses in +/+ mucosa. Unexpectedly, NPY,/, colon exhibited significantly attenuated veratridine responses (between 1 and 5 min). We demonstrate that electrogenic veratridine responses in mouse colon are noncholinergic and that NPY can act directly upon epithelia, a Y1 receptor effect. The enhanced veratridine response observed in +/+ tissue following BIIE0246, indicates that Y2 receptors are located on submucosal neurons and that their activation by NPY will inhibit enteric noncholinergic secretory neurotransmission. We also demonstrate Y1 and Y2 receptor-mediated antisecretory tone in +/+ colon and show selective loss of each in Y1 and Y2 null colon respectively. In NPY,/, tissue, only Y1 -mediated tone was present, this presumably being mediated by endogenous endocrine peptide YY. Y2 tone was absent from NPY,/, (and Y2,/,) colon and we conclude that NPY activation of neuronal Y2 receptors attenuates secretory neurotransmission thereby providing an absorptive electrolyte tone in isolated colon. British Journal of Pharmacology (2005) 146, 712,722. doi:10.1038/sj.bjp.0706368 [source] Differential sensitivity to apoptosis between the human small and large intestinal mucosae: Linkage with segment-specific regulation of Bcl-2 homologs and involvement of signaling pathways,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2001Rémy Gauthier Abstract The small and large intestines differ in their expression profiles of Bcl-2 homologs. Intestinal segment-specific Bcl-2 homolog expression profiles are acquired as early as by mid-gestation (18,20 weeks) in man. In the present study, we examined the question whether such distinctions underlie segment-specific control mechanisms of intestinal cell survival. Using mid-gestation human jejunum and colon organotypic cultures, we analyzed the impact of growth factors (namely insulin; 10 ,g/ml) and pharmacological compounds that inhibit signal transduction molecules/pathways (namely tyrosine kinases, Fak, PI3-K/Akt, and MEK/Erk) on cell survival and Bcl-2 homolog expression (anti-apoptotic: Bcl-2, Bcl-XL, Mcl-1; pro-apoptotic: Bax, Bak, Bad). The relative activation levels of p125Fak, p42Erk-2, and p57Akt were analyzed as well. Herein, we report that (1) the inhibition of signal transduction molecules/pathways revealed striking differences in their impact on cell survival in the jejunum and colon (e.g., the inhibition of p125Fak induced apoptosis with a significantly greater extent in the jejunum [,43%] than in the colon [,24%]); (2) sharp distinctions between the two segments were noted in the modulatory effects of the various treatments on Bcl-2 homolog steady-state levels (e.g., inhibition of tyrosine kinase activities in the jejunum down-regulated all anti-apoptotics analyzed while increasing Bax, whereas the same treatment in the colon down-regulated Bcl-XL only and increased all pro-apoptotics); and (3) in addition to their differential impact on cell survival and Bcl-2 homolog expression, the MEK/Erk and PI3-K/Akt pathways were found to be distinctively regulated in the jejunum and colon mucosae (e.g., insulin in the jejunum increased p42Erk-2 activation without affecting that of p57Akt, whereas the sa e treatment in the colon decreased p42Erk-2 activation while increasing that of p57Akt). Altogether, these data show that intestinal cell survival is characterized by segment-specific susceptibilities to apoptosis, which are in turn linked with segmental distinctions in the involvement of signaling pathways and the regulation of Bcl-2 homolog steady-state levels. Therefore, these indicate that cell survival is subject to segment-specific control mechanisms along the proximal-distal axis of the intestine. J. Cell. Biochem. 82: 339,355, 2001. © 2001 Wiley-Liss, Inc. [source] | ||||||||||