Colon Of Ulcerative Colitis Patients Research Articles

Pan-colonic field defects are detected by CGH in the colons of UC patients with dysplasia/cancer

BAC arrays were used to evaluate genomic instability along the colon of patients with ulcerative colitis (UC). Genomic instability increases with disease progression and biopsies more proximal to dysplasia showed increased instability. Pan-colonic field copy number gain or loss involving small (<1Mb) regions were detected in most patients and were particularly apparent in the UC progressor patients who had dysplasia or cancer. Chromosomal copy gains or losses affecting large regions were mainly restricted to dysplastic biopsies. Areas of significant chromosomal losses were detected in the UC progressors on chromosomes 2q36, 3q25, 3p21, 4q34, 4p16.2, 15q22, and 16p13 (p-value⩽0.04). These results extend our understanding of the dynamic nature of pan-colonic genomic instability in this disease.

Epithelial Expression of Vasoactive Intestinal Peptide in Ulcerative Colitis: Down-Regulation in Markedly Inflamed Colon

Vasoactive intestinal peptide (VIP) has a number of important effects in intestinal physiology and pathology, including in ulcerative colitis (UC). The expression patterns of the predominant VIP receptor in the mucosa (the VPAC1 receptor) are unknown for the mucosa in UC. It is assumed that the sources of VIP in the intestine are the innervation and the inflammatory cells. The VIP and VPAC1 receptor expression patterns in the epithelial layer of UC and non-UC patients were examined in the present study. The influence of marked inflammation of the mucosa was evaluated. Specimens of the human colon, including the colon of UC patients, were examined concerning expressions of VIP and VPAC1 receptor, focusing on the epithelial layer. Immunohistochemistry and in situ hybridization were utilized. There were VIP mRNA reactions and also marked VPAC1 receptor immunoreactions in the normal and slightly/moderately affected epithelium. VIP mRNA reactions were not detected and VPAC1 immunoreactions were minimal in response to marked mucosal derangement. The findings suggest that there is a local production of VIP in the epithelial cells in normal and slightly/moderately inflamed mucosa but not in severely inflamed mucosa. Furthermore, a marked downregulation in VPAC1 receptor expressions occurs in the epithelium in severe UC. Based on the knowledge that VIP can have trophic, healing and anti-inflammatory effects, it is likely that the decrease in VIP mRNA and VPAC1 receptor reactions seen in severely affected mucosa in UC may be associated with adverse effects on intestinal function.

Effects of Probiotics on Serum Bile Acids in Patients With Ulcerative Colitis

BACKGROUND/AIM: Evaluation of bile acids (BA) is a useful method for assessing changes of the intestinal flora in patients with ulcerative colitis (UC). During enterohepatic circulation, conjugated BA is deconjugated to free BA by intestinal bacteria. The presence of intestinal microflora (Clostridium and Eubacterium) leads to 7 alpha-dehydroxylation of cholic acid (CA) and chenodeoxycholic acid (CDCA), yielding deoxycholic acid (DCA) and lithocholic acid, respectively. It was reported that the Lachnospiraceae subgroup of Firmicutes (including Clostridium) are decreased in the colon of UC patients compared to controls without inflammatory bowel disease. We have already reported that the serum%CDCA is significantly higher in patients with UC than in healthy volunteers (HV), while serum%DCA is significantly lower in UC patients than in HV, and these changes do not depend on the activity or extent of UC. The aim of the present study was to elucidate the effects of probiotics in patients with UC by examining the serum BA profile. PATIENTS/METHODS: The study population was 27 patients in whom UC was diagnosed from endoscopic and histological findings. All patients underwent ileocolonoscopy with appropriate biopsies. They were divided into the following 2 groups based on endoscopic findings: 15 patients with distal UC (dUC) and diffuse changes extending from the rectum to the splenic flexure, and 12 patients with more extensive UC or pancolitis (pUC). Treatment was givenwithmesalazine or salazosulfapyridine (5-ASA) and all patients achieved remission. After entering remission, they were treated with by 5-ASA plus the probiotic Clostridium butyricum Miyairi (MIYA) (3 g/day) for 4 weeks. The control group was composed of 8 HV. Routine laboratory tests were performed on the basis of clinical need, while fasting serum samples for measurement of BA were obtained before and after treatment with 5-ASA plus MIYA for 4 weeks. Serum BA fractions were analyzed by HPLC. RESULTS: There were no significant differences of serum total BA among the 3 groups. Before treatment, %CDCA was significantly higher in the dUC and pUC groups than in the HV group, while %DCA was significantly lower than in the HV group. In the pUC group, %CDCA was significantly higher and %DCA was significantly lower than in the HV group after 4 weeks of probiotic treatment. In the dUC group, however, there was no significant difference of %CDCA or %DCA after 4 weeks compared with the HV group. There were no significant differences in the ratio of conjugated BA to total serum BA among the three groups. CONCLUSIONS: These results suggest that intestinal bacteria involved in the deconjugation of BA are restored when patients achieve remission of UC by treatment with 5-ASA, and thatMIYA restoredmicroflora involved in 7 alpha-dehydroxylation in the dUC group, but not in the pUC group.

Immunoglobulin A: FcαRI Interactions Induce Neutrophil Migration Through Release of Leukotriene B4

Exacerbations of ulcerative colitis (UC) are dominated by massive neutrophil influx in the lamina propria with concomitant mucosal ulceration. The prevalent antibody in this area is immunoglobulin A (IgA). Interestingly, the IgA Fc receptor (Fc(alpha)RI) potently activates neutrophils. As such, we investigated whether IgA-Fc(alpha)RI interaction contributes to tissue damage in UC. Response of neutrophils to bovine serum albumin-, IgG-, or IgA-coated beads and Escherichia coli was investigated with 3-dimensional culture systems, real-time video microscopy, and (fluorescence) microscopy. In vivo studies were performed using human Fc(alpha)RI transgenic mice or nontransgenic littermates. Microscopic slides of UC patients were stained for IgA, Fc(alpha)RI, and neutrophils. In vitro and in vivo cross-linking of Fc(alpha)RI on neutrophils by serum IgA or uptake of IgA-coated E coli led to neutrophil migration. The responsible chemotactic factor was identified as leukotriene B4. Moreover, dimeric IgA (dIgA), which is produced in the lamina propria, but neither secretory IgA nor IgG, was equally capable of inducing neutrophil recruitment. We furthermore showed that Fc(alpha)RI(+)-neutrophils in the colon of UC patients had phagocytosed IgA-antigen complexes. Neutrophils are the first cells that arrive at inflammatory sites once pathogens have crossed the epithelial barrier. Fc(alpha)RI-dIgA interactions therefore may constitute an essential activation step to recruit more neutrophils, hereby eradicating impending infections. However, excessive IgA-antigen complexes can sustain a perpetuating inflammatory loop in UC, hereby seriously aggravating morbidity. Novel therapeutic strategies that block dIgA-Fc(alpha)RI interactions, and therefore diminish neutrophil migration and activation, may dampen the uncontrolled inflammatory processes in these patients.

Increased intestinal expression of heme oxygenase‐1 and its localization in patients with ulcerative colitis

Heme oxygenase-1 (HO-1) is regarded as a sensitive and reliable indicator of cellular oxidative stress. Two end products of heme degradation, carbon monoxide (CO) and bilirubin, are involved in the protective role of HO-1 against oxidative injury. We have demonstrated enhanced expression of this enzyme and increased concentration of CO in experimental models of colitis, but the role of HO-1 in patients with ulcerative colitis (UC) has not been extensively investigated. The aim of the present study was to determine the intestinal levels and localization of ho-1 mRNA and HO-1 protein in patients with UC. Eighteen patients with UC and 13 patients with colon cancer were prospectively selected from subjects who underwent colonoscopy. Biopsy specimens were obtained from the inflamed mucosa of UC patients and from the normal mucosa at least 5 cm from the margin of carcinoma. The expression of ho-1 mRNA was assayed by real-time polymerase chain reaction (PCR). The colonic expression of HO-1 was determined by immunohistochemistry and western blotting using a monoclonal antibody against HO-1. The expression of ho-1 mRNA and HO-1 protein was significantly increased in the colonic mucosa of patients with active UC compared with normal mucosa. In the patients with active UC, mononuclear cells in the submucosa of the colon were positive for HO-1, and there was negligible staining in the epithelial cells. The present findings are evidence of the induction of HO-1 in the colon of UC patients.

M1197 Breast Cancer Resistance Protein (BCRP/ABCG2) Is Equally Distributed Throughout the Colon of Patients with Ulcerative Colitis and Its Expression Is Decreased in Active Inflammation

Background and aim: Breast Cancer Resistance Protein (BCRP/ABCG2) is an active efflux transporter located on the apical membrane of epithelial cells of the gastrointestinal tract. BCRP is important for the detoxification of exogenous xenobiotics. In healthy controls, a gradual decline of expression was found from the proximal to the distal colon. However, no data are available on the distribution of BCRP in the colon of patients with ulcerative colitis (UC). Therefore, we investigated the distribution of BCRP in inflamed and noninflamed UC. Methods: Biopsy specimens from patients with UC were obtained from the pathology archive of the Erasmus Medical Center, Rotterdam. For each patient, samples were selected from the rightand left-sided colon. Histological staging of inflammation was determined by an expert gastrointestinal pathologist, according to the Geboes scoring system. BCRP expression was detected by immunohistochemistry using a specific anti-human BCRP antibody. Expression of BCRP was defined as positive, heterogeneous, or negative if respectively >50%, >15-50%, <15% of the apical membranes of the epithelial cells were positive. Results: Sixty-eight biopsies of 34 UC patients (mean age 42 year, 54% male) were obtained. Sixteen patients had active colitis of either the complete (n=12) or left-sided (n=4) colon, whereas 18 patients had inactive colitis. Of the biopsies of patients with active colitis (pancolitis n=24, left-sided colitis n=4), 57% (16/28) showed no expression of BCRP, 25% (7/28) heterogeneous expression, and 18% (5/28) a positive expression. Of the biopsies of patients with inactive colitis (inactive colitis n=36, left-sided colitis n=4) the expression of BCRP was negative in 5% (2/40), heterogeneous in 10% (4/40) and positive in 85% (34/ 40). Statistical analysis demonstrates a significant inverse correlation between inflammation and expression levels of BCRP (p < 0.001). No significant differences were seen in the expression levels of BCRP at the ascending and descending colon within subjects (p = 0.7). In patients with left sided colitis (n=4), BCRP expression was positive at both sides. Conclusion: Overall, no difference was seen in the distribution of BCRP in the rightand left-sided colon in UC patients. This is in contrast to earlier data in healthy controls. In patients with pancolitis, BCRP expression was down regulated in all biopsies. These findings need further exploration to elucidate its importance in the clearance of toxic substrates in the gut lumen.

Alterations in intestinal fatty acid metabolism in inflammatory bowel disease

Inflammatory bowel disease (IBD) constitutes a severe intestinal disorder in developed countries with increasing incidence worldwide. Upcoming evidence indicates an important role of intestinal epithelial barrier function in the development of IBD. Fatty acids exert nutritional and protective effects on enterocytes, serve as activators of transcription and constitute precursors of inflammatory mediators. The aim of this study was to investigate differential regulation of genes involved in fatty acid uptake and endogenous fatty acid biosynthesis in IBD. Mucosal biopsy specimens from non-affected regions of the intestine were subjected to DNA microarray analysis. Gene array analysis revealed a variety of genes involved in fatty acid uptake and synthesis to be differentially expressed in ileum and colon of selected IBD patients. To verify these results, real-time RT-PCR was performed for selected regulated candidate genes in larger IBD sample numbers. In single biopsy analysis long chain acyl-CoA synthetase (ACSL) 1 and 4 were upregulated in IBD (P<0.05), while a significant decrease in fatty acid synthase expression was found in ileum and colon of ulcerative colitis patients (P<0.001). Expression of the transcription factor liver X receptor (LXR) which was previously shown to induce fatty acid synthase gene expression was not altered on mRNA level in IBD. However, in cell culture experiments using the human intestinal cell line LS174T induction of fatty acid synthase by the LXR ligand T0901317 was inhibited by TNFalpha. Moreover, these experiments indicated a decrease of LXR protein levels by TNFalpha treatment. These data suggest that the decrease of fatty acid synthase expression in ulcerative colitis patients could be at least partially due to a loss of LXR expression and function in the presence of pro-inflammatory cytokines. Observed alterations in expression of genes of fatty acid metabolism may contribute to the pathophysiology of ulcerative colitis.

The adaptive imbalance in base excision–repair enzymes generates microsatellite instability in chronic inflammation

Chronic infection and associated inflammation are key contributors to human carcinogenesis. Ulcerative colitis (UC) is an oxyradical overload disease and is characterized by free radical stress and colon cancer proneness. Here we examined tissues from noncancerous colons of ulcerative colitis patients to determine (a) the activity of two base excision–repair enzymes , AAG, the major 3-methyladenine DNA glycosylase, and APE1, the major apurinic site endonuclease; and (b) the prevalence of microsatellite instability (MSI). AAG and APE1 were significantly increased in UC colon epithelium undergoing elevated inflammation and MSI was positively correlated with their imbalanced enzymatic activities. These latter results were supported by mechanistic studies using yeast and human cell models in which overexpression of AAG and/or APE1 was associated with frameshift mutations and MSI. Our results are consistent with the hypothesis that the adaptive and imbalanced increase in AAG and APE1 is a novel mechanism contributing to MSI in patients with UC and may extend to chronic inflammatory or other diseases with MSI of unknown etiology.

The adaptive imbalance in base excision-repair enzymes generates microsatellite instability in chronic inflammation.

Chronic infection and associated inflammation are key contributors to human carcinogenesis. Ulcerative colitis (UC) is an oxyradical overload disease and is characterized by free radical stress and colon cancer proneness. Here we examined tissues from noncancerous colons of ulcerative colitis patients to determine (a) the activity of two base excision-repair enzymes, AAG, the major 3-methyladenine DNA glycosylase, and APE1, the major apurinic site endonuclease; and (b) the prevalence of microsatellite instability (MSI). AAG and APE1 were significantly increased in UC colon epithelium undergoing elevated inflammation and MSI was positively correlated with their imbalanced enzymatic activities. These latter results were supported by mechanistic studies using yeast and human cell models in which overexpression of AAG and/or APE1 was associated with frameshift mutations and MSI. Our results are consistent with the hypothesis that the adaptive and imbalanced increase in AAG and APE1 is a novel mechanism contributing to MSI in patients with UC and may extend to chronic inflammatory or other diseases with MSI of unknown etiology.

Spontaneous contractions and some electrophysiologic properties of circular muscle from normal sigmoid colon and ulcerative colitis

Spontaneous contractions, inhibitory responses produced by electrical field stimulation, and some electrophysiologic properties of circular smooth muscle from normal sigmoid colon and from sigmoid colon of ulcerative colitis patients were compared in vitro using simultaneous recordings of mechanical and intracellular electrical activity. In normal colonic circular muscle obtained from 21 patients, the frequency of spontaneous summation contractions ranged from 3 to 7 per 4 min, whereas in circular muscle from 13 patients with ulcerative colitis, the frequency of these contractions ranged from 1 to 9 per 4 min. Nonadrenergic, noncholinergic relaxation produced by electrical field stimulation was recorded in the majority of circular smooth muscle strips from both normal colon and colon from patients with ulcerative colitis. There were no significant differences in mean resting membrane potential, mean slow-wave frequency, mean maximum slow-wave amplitude, or inhibitory-junction potential amplitudes recorded using circular smooth muscle from both normal colon and colon from patients with ulcerative colitis. There appeared to be a weak association in patients with ulcerative colitis between increasing duration of symptoms and decreasing frequency of spontaneous summation contractions, but there were no associations between the frequency of these contractions and the severity of colonic inflammation, patient age, or the frequency of stools. The mechanism accounting for a wider range in the frequency of summation contractions recorded from colonic circular smooth muscle in ulcerative colitis remains to be determined.