Rectal Mucosa Of Patients Research Articles

Effects of obesity, and of weight loss following bariatric surgery, on methylation of DNA from the rectal mucosa and in cell-free DNA from blood.

DNA methylation is an epigenetic mechanism through which environmental factors including nutrition and inflammation influence health. Obesity is a major modifiable risk factor for many common diseases including cardiovascular diseases and cancer. In particular, obesity-induced inflammation resulting from aberrantly-methylated inflammatory genes may drive risk of several non-communicable diseases including colorectal cancer (CRC). This study is the first to investigate the effects of weight loss induced by bariatric surgery (BS) on DNA methylation in the rectum and in cell-free DNA (cfDNA) from blood. DNA methylation was quantified in rectal mucosal biopsies and cfDNA from serum of 28 participants with obesity before and 6 months after BS, as well as in 12 participants without obesity (control group) matched for age and sex from the Biomarkers Of Colorectal cancer After Bariatric Surgery (BOCABS) Study. DNA methylation of LEP, IL6, POMC, LINE1, MAPK7 and COX2 was quantified by pyrosequencing. BMI decreased significantly from 41.8 kg/m2 pre-surgery to 32.3 kg/m2 at 6 months after BS. Compared with the control group, obesity was associated with lower LEP methylation in both the rectal mucosa and in cfDNA from serum. BS normalised LEP methylation in DNA from the rectal mucosa but not in cfDNA. BS decreased methylation of some CpG sites of LINE1 in the rectal mucosal DNA and in cfDNA to levels comparable with those in participants without obesity. Methylation of POMC in rectal mucosal DNA was normalised at 6 months after BS. BS reversed LINE1, POMC and LEP methylation in the rectal mucosa of patients with obesity to levels similar to those in individuals without obesity. These findings support current evidence of effects of BS-induced weight loss on reversibility of DNA methylation in other tissues. The DNA methylation changes in the rectal mucosa shows promise as a biomarker for objective assessment of effects of weight loss interventions on risk of cancer and other diseases.

Ferroptosis in the colon epithelial cells as a therapeutic target for ulcerative colitis.

Ferroptosis, a type of programmed cell death triggered by oxidative stress, was suspected to play a role in ulcerative colitis. Indigo naturalis is highly effective against ulcerative colitis, but its mechanism is unclear. This study found that indigo naturalis treatment suppressed ferroptosis. We analyzed 770 mRNA expressions of patients with ulcerative colitis. Suppression of ferroptosis by indigo naturalis treatment was shown using a cell death assay. Malondialdehyde levels and reactive oxygen species were analyzed in CaCo-2 cells treated with indigo naturalis. Glutathione metabolism was shown by metabolomic analysis. Extraction of the ingredients indigo naturalis from the rectal mucosa was performed using liquid chromatograph-mass spectrometry. Gene expression profiling showed that indigo naturalis treatment increased antioxidant genes in the mucosa of patients with ulcerative colitis. In vitro analysis showed that nuclear factor erythroid-2-related factor 2-related antioxidant gene expression was upregulated by indigo naturalis. Indigo naturalis treatment rendered cells resistant to ferroptosis. Metabolomic analysis suggested that an increase in reduced glutathione by indigo naturalis. The protein expression of CYP1A1 and GPX4 was increased in the rectum by treatment with indigo naturalis. The main ingredients of indigo naturalis, indirubin and indigo inhibited ferroptosis. Indirubin was detected in the rectal mucosa of patients with ulcerative colitis who were treated with indigo naturalis. Suppression of ferroptosis by indigo naturalis in the intestinal epithelium could be therapeutic target for ulcerative colitis. The main active ingredient of indigo naturalis may be indirubin.

SARS-CoV-2 Interacts with Mucosal Dysbiosis to Cause the Wide Range of Disease Seen in Covid-19

Hypothesis: SARS-CoV-2 amplifies pre-existing dysbiosis induced mucosal inflammation and this can cause a severe systemic inflammatory disease. The microbial flora perturbation can persist long after the virus has been eliminated leading to a wide range of long Covid symptoms. Evidence: Dysbiosis induced mucosal inflammation increases with age and is strongly associated with the metabolic syndrome (obesity, type 2 diabetes mellitus, ischaemic heart disease, hypertension, and depression). These are risk factors for the conversion of mild to severe Covid-19. Certain common strains of Staphylococcus aureus, which is commonly carried in pharyngeal mucosa, can trigger a cytokine cascade as seen in severe Covid-19. Blood group A and vitamin D deficiency, which are risk factors for hospitalisation in Covid-19 are also associated with increased S. aureus pharyngeal carriage rates. Multi-inflammatory syndrome in children is a post Covid condition which resembles toxic shock syndrome and Kawasaki disease (the former is known to be caused by staphylococcal pyrogenic toxins). A number of studies have shown dysbiosis of the oral mucosa and rectal mucosa in patients who progress to severe Covid-19. The wide range of pathology seen during and following SARS-CoV-2 infection is more in keeping with dysbiosis induced inflammation (multiple pathogenic bacteria at multiple sites) than with an otherwise simple viral induced respiratory tract infection. Implication: Optimization of the microbial flora, prior to encountering the virus, could have reduced the severity of the pandemic. The consumption of fermented foods, especially yoghurt, holds the most promise for reducing dysbiosis induced mucosal inflammation and preventing a wide range of complications. Reduced mucosal inflammation brings not only health but also happiness in which oxytocin has a key role.

Predominance of Type 1 Innate Lymphoid Cells in the Rectal Mucosa of Patients With Non-Celiac Wheat Sensitivity: Reversal After a Wheat-Free Diet.

OBJECTIVES:Non-celiac wheat sensitivity (NCWS) is defined as a reaction to ingested wheat after exclusion of celiac disease and wheat allergy. As its pathogenesis is incompletely understood, we evaluated the inflammatory response in the rectal mucosa of patients with well-defined NCWS.METHODS:The prospective study included 22 patients with irritable bowel syndrome (IBS)-like clinical presentation, diagnosed with NCWS by double-blind placebo-controlled challenge. Eight IBS patients not improving on wheat-free diet were used as controls. Two weeks after oral challenge was performed with 80 grams of wheat daily, cells were isolated from rectal biopsies and thoroughly characterized by fluorescence-activated cell sorting analysis for intracellular cytokines and surface markers.RESULTS:Rectal biopsies from wheat-challenged NCWS patients showed that a significant mucosal CD45+ infiltrate consisted of CD3+ and CD3− lymphocytes, with the latter spontaneously producing more interferon (IFN)-γ than IBS controls. About 30% of IFN-γ-producing CD45+ cells were T-bet+, CD56−, NKP44−, and CD117−, defining them as a type-1 innate lymphoid cells (ILC1). IFN-γ-producing ILC1 cells significantly decreased in 10 patients analyzed 2 weeks after they resumed a wheat-free diet.CONCLUSIONS:These data indicate that, in patients with active NCWS, IFN-γ-producing ILC1 cells infiltrate rectal mucosa and support a role for this innate lymphoid cell population in the pathogenesis of NCWS.

Identification of Patients With Developing Ulcerative Colitis–associated Neoplasia by Nitrative DNA Damage Marker 8-Nitroguanin Expression in Rectal Mucosa

To clarify whether the expression of nitrative and oxidative DNA damage markers in the rectal mucosa of patients with ulcerative colitis (UC) could be used to predict UC-associated neoplasia. A longer duration of UC can increase the risk of developing UC-associated cancer (UCAC). Effective diagnostic markers are being sought to provide more selective screening and treatment strategies for patients with long-standing UC. A total of 141 patients with UC who underwent a proctocolectomy were enrolled in this study. The expression of 8-nitroguanine (8-NG), 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), and inducible nitric oxide synthase (iNOS) in the rectal mucosa were evaluated using immunohistochemistry (IHC) and assessed relative to the pathogenesis of UC-associated neoplasia. Eighteen patients (12.8%) had UC-associated neoplasia including low-grade or high-grade dysplasia and UCAC. IHC scores of 8-NG in UC-associated neoplasia group was significantly higher than in non-neoplasia group (P<0.0001). In contrast, IHC score of 8-oxodG in non-neoplasia group was significantly decreased compared with UC-associated neoplasia group (P=0.0028). In logistic regression analysis, duration of disease >8 years, high IHC scores of 8-NG, and low 8-oxodG in the rectal mucosa were significantly associated with the development of UC-associated neoplasia (P<0.01). The expression of 8-NG was more frequently observed in patients with UCAC than in patients with sporadic colorectal cancer (P<0.01). These results suggest that evaluating the expression levels of 8-NG in the rectal mucosa may be a useful biomarker for detecting patients with UC-associated neoplasia.

Association of Genetically Related Escherichia coli Strains with Ulcerative Colitis - A Preliminary Study

Objective: To explore the genetic relatedness among the Escherichia coli isolates recovered from rectal mucosa of patients with Ulcerative Colitis(UC) as well as from non specific diarrhoea patients by using ERIC PCR (whole genome analysis). Material &amp; Methods: A total of 44 strains of E coli, each from patients suffering from UC with exacerbation while on maintenance therapy, were isolated to see if there is any association with specific genotype of E coli with the clini-cal condition. For comparison, 20 strains of E coli were also isolated from patients suffering from non specific diarrhoea. These isolates were subjected to ERIC PCR for analysing similarity/ dissimilarity with each other based on the distribution of ERIC sequences in the whole genome of the bacterial species. Results: The dendrogram prepared on the basis of banding pattern showed that majority of UC patients (39/44, 88.6%) grouped in to one major cluster while second major cluster comprised mostly strains isolated from patients with non specific diarrhoea i.e. controls (17/18, 94.4%). Moreover, in the cluster representing UC patients, a total of 11 strains were observed to be genotypically similar followed by 8 strains by ERIC PCR. Conclusion: Our results strongly indicate that specific Escherichia coli strains may be involved/ associated with UC and its relapse. Key Words: Ulcerative colitis; Escherichia coli; ERIC; PCR DOI: http://dx.doi.org/10.3126/ajms.v2i2.4769Asian Journal of Medical Sciences 2 (2011) 93-96

THe rectal mucosa in patients with crohn's anal fistulae harbours lower numbers of bifidobacteria, and the fistula tracts are devoid of a microbial ecosystem

IntroductionThe aetiology of Crohn's perianal fistulae remains obscure but genetic, microbial and immune factors play a role. For example, faecal diversion and antimicrobial treatment are partially efficacious in some Crohn's...

W1267 Thiopurine-Induced Peripheral T Cells Apoptosis and Drug Response in Patients With Crohn's Disease

The standard treatment of IBD involves the application of anti-inflammatory drugs. These drugs become systemically bioavailable and bear a potential of strong adverse effects. Thus, targeting the inflamed areas of the intestine can reduce adverse effects. Polymeric particles have turned out to be a promising tool for the targeted delivery of drugs. We aimed to investigate the distribution of fluoresceine-labelled nanoparticles (NP) and microparticles (MP) in the rectal mucosa of patients with IBD by use of CLE. Fluoresceinaminewas covalently bound to poly(L-lactide-co-glycolide) (PLGA). From this modified polymer, nanoparticles of approximately 300 nm size and microparticles of 3.5 μm size were prepared. After bowel preparation a 30 ml enema containing 10E9 MP or 10E13 NP, resp., has been applied to patients with rectal Crohns disease (CD) or ulcerative colitis (UC). After two hours endoscope based CLE has been performed to visualize nanoparticles in areas of different stages of inflammation. Biopsies have been obtained from IBD patients to evaluate mucosal transport processes in miniaturized Ussing chambers by confocal laser endoscopy. We examined 16 patients with IBD (8 patients with CD, 10 patients with (UC), 7 of whom received NP while 9 received MP. No particles have been visualized on intact mucosal surfaces. In areas of mild to moderate inflammation only minor amounts of particles were visible. In contrast, we observed a marked accumulation of MP rather than NP in ulcerous lesions. Preliminary results from Ussing chamber experiments suggest an influx of particles into the gut mucosa through epithelial lesions. Representative images are shown in fig. 1. This is the first study demonstrating mucosal accumulation of microparticles and nanoparticles in intestinal lesions of patients with IBD. Drug containing particles may have a great potential to target these lesions more specifically in order to maximize therapeutic efficacy and minimize potential side effects. CLE is a useful tool to investigate drug delivery to mucosal surfaces.

W1266 Confocal Laser Endomicroscopy (CLE) Reveals Mucosal Accumulation of Plga-Nanoparticles in Ulcerous Lesions of Patients With Inflammatory Bowel Diseases

The standard treatment of IBD involves the application of anti-inflammatory drugs. These drugs become systemically bioavailable and bear a potential of strong adverse effects. Thus, targeting the inflamed areas of the intestine can reduce adverse effects. Polymeric particles have turned out to be a promising tool for the targeted delivery of drugs. We aimed to investigate the distribution of fluoresceine-labelled nanoparticles (NP) and microparticles (MP) in the rectal mucosa of patients with IBD by use of CLE. Fluoresceinaminewas covalently bound to poly(L-lactide-co-glycolide) (PLGA). From this modified polymer, nanoparticles of approximately 300 nm size and microparticles of 3.5 μm size were prepared. After bowel preparation a 30 ml enema containing 10E9 MP or 10E13 NP, resp., has been applied to patients with rectal Crohns disease (CD) or ulcerative colitis (UC). After two hours endoscope based CLE has been performed to visualize nanoparticles in areas of different stages of inflammation. Biopsies have been obtained from IBD patients to evaluate mucosal transport processes in miniaturized Ussing chambers by confocal laser endoscopy. We examined 16 patients with IBD (8 patients with CD, 10 patients with (UC), 7 of whom received NP while 9 received MP. No particles have been visualized on intact mucosal surfaces. In areas of mild to moderate inflammation only minor amounts of particles were visible. In contrast, we observed a marked accumulation of MP rather than NP in ulcerous lesions. Preliminary results from Ussing chamber experiments suggest an influx of particles into the gut mucosa through epithelial lesions. Representative images are shown in fig. 1. This is the first study demonstrating mucosal accumulation of microparticles and nanoparticles in intestinal lesions of patients with IBD. Drug containing particles may have a great potential to target these lesions more specifically in order to maximize therapeutic efficacy and minimize potential side effects. CLE is a useful tool to investigate drug delivery to mucosal surfaces.

Real-time PCR quantification analysis of five mucosal transcripts in patients with Crohnʼs disease

Crohn's disease has a genetic background. Onset of the clinical manifestations, however, is suggested to be triggered by environmental factors. Microarray analysis has shown that the expression of transcripts aldolase B, elafin, MST-1, simNIPhom and SLC6A14 are altered in patients with ulcerative colitis. The primary aim of this study was to explore the expressions of these five transcripts in macroscopically inflamed and noninflamed mucosa in patients with Crohn's disease. Mucosal specimens obtained from colon in consecutive patients with Crohn's disease (n=23) and controls (n=67) undergoing colonoscopy were analyzed using real-time PCR technique. The expressions of the transcripts aldolase B, elafin, simNIPhom and SLC6A14 were increased, whereas the expression of MST-1 was decreased in noninflamed rectal mucosa in patients with Crohn's disease compared with controls. The expression of aldolase B was increased and the expressions of elafin and simNIPhom were decreased in inflamed colonic mucosa compared with noninflamed rectal mucosa in patients with Crohn's disease. No correlation, between the clinical activity of Crohn's disease (Mayo score <or=5 vs. >or=6) and transcript expression was detected. The mucosal transcript pattern in Crohn's disease may, based on the known biological function of the transcripts, explain some of the typical features of Crohn's disease and indicate a possible pathophysiological role of microbes. Our results may thereby contribute to the understanding of the pathogenesis and manifestations of Crohn's disease.

750 Identification of Inherited Predisposition to Colonic Neoplasia Through Partial Wave Spectroscopic Analysis of the Microscopically Normal Colonic Epithelium

While familial risk comprises ~20-30% of all colorectal cancers (CRC), in most cases the genetic etiology is not readily identifiable. Thus, counselling CRC-prone families members is not based on individized risk assessment (e.g. one size fits all approach). Our group has developed novel light scattering technologies such as partial wave spectroscopy (PWS)to quantitate nanoscale architecture. We have noted that pre-dysplastic mucosal optical signatures provided a highly sensitive means of detecting CRC risk in experimental models(Gastro 2004, CEBP 2005, Clin Cancer Res 2006). Moreover, the PWS parameter, disorder strength (Ld), was markedly elevated in the endoscopically normal rectal mucosa of patients harboring adenomas (i.e. “field effect”). We now explore whether colonic Ld could detect a genetic predisposition to CRC. Methods: Animal studies: MIN (murine model of FAP with APC gene mutation) or age-matched wildtype mice were euthanized and had intestinal brushings taken of neoplasia-free areas Human Studies 35 patients with HNPCC mutation-confirmed (hMLH-1&hMSH-2),adenoma-free or controls (age-matched but no personal/family history) had rectal brushings taken during colonoscopy. PWS analysis: Ld and standard deviation of Ld (SDLd) were calculated by investigator blinded to clinical findings Results Ld was markedly elevated in the normal mucosa of germline carriers when compared to controls (figure). This, coupled with SDLd, allowed clear descrimination between cases and controls(both murine and human model. Conclusions: Ld and SDLd from the visually normal mucosa identified APC and hMLH1/hMSH2 mutations prior to phenotype development. Thus, probing nanoscale perturbations from readily accessible mucosa (e.g. rectum) may provide a modality for determing both the carriage of these syndromic mutations and possibly allow detection of the more common lower penetrant CRC risk genes.

Normalization of substance P levels in rectal mucosa of patients with faecal incontinence treated successfully by sacral nerve stimulation

Sacral nerve stimulation (SNS) may improve faecal incontinence by modulating rectal sensation. This study measured changes in the peripheral expression of various neural epitopes in response to SNS. Rectal mucosal biopsies were taken from 12 patients before and after temporary SNS, and from ten responders at 90 days after permanent stimulation. Sections were immunostained for substance P, transient receptor potential vanilloid (TRPV) 1, vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP). Levels were compared with those in nine continent controls. Baseline levels of percentage area immunoreactivities of substance P (median 0.51 (95 per cent confidence interval 0.31 to 0.73) versus 0.13 (0.07 to 0.27) per cent; P < 0.001) and TRPV1 (0.76 (0.41 to 1.11) versus 0.09 (0.04 to 0.14) per cent; P < 0.001), but not of VIP (1.26 (0.37 to 2.15) versus 1.28 (0.39 to 2.17); P = 0.943), were significantly greater than in controls. Successful SNS resulted in a significant decrease in substance P immunostaining after temporary (0.15 (0.06 to 0.51) per cent; P = 0.051) and permanent (0.17 (0 to 0.46) per cent; P = 0.051) stimulation. Immunoreactivity of TRPV1, VIP, CGRP and neural markers showed no qualitative change. Patients with faecal incontinence demonstrate normalization of raised rectal mucosal substance P levels following successful SNS.

Increased concentrations of l-lactate in the rectal lumen in patients undergoing cardiopulmonary bypass

Gut ischaemia may contribute to morbidity in patients after cardiopulmonary bypass (CPB), but little is known about the metabolic state of the large bowel in such patients. Therefore we estimated the concentrations of L-lactate and Pco(2) in rectal mucosa in patients undergoing cardiac surgery with or without the use of CPB. Patients undergoing coronary artery bypass grafting (CABG) (n=12) or off-pump CABG (n=10) were subjected to equilibrium dialysis of the rectal lumen during the procedure and in the first 4 h afterwards. Dialysate concentrations of L-lactate and Pco(2) were measured using an auto-analyser and compared with values obtained in healthy subjects (n=10). During CPB, a 2- to 3-fold increase in luminal concentrations of L-lactate was observed (CABG vs off-pump CABG, P=0.05; CABG vs healthy subjects, P<0.01). The dialysate concentrations of L-lactate were higher than the mean systemic values (luminal-arterial gradient mean (sd) 0.9 (1.0) mmol litre(-1), P<0.05), and the two values were positively correlated (P<0.05). Luminal L-lactate concentrations remained elevated 4 h after the operation. In contrast, dialysate Pco(2) was equally high in patient and control groups and substantially higher than values observed in arterial blood. Uncomplicated CPB is associated with moderate but sustained increases in luminal concentrations of L-lactate in the rectum, indicating metabolic dysfunction of the mucosa in the large bowel.

Chemotaxonomic analysis of bacterial populations colonizing the rectal mucosa in patients with ulcerative colitis.

The etiology of ulcerative colitis (UC) is unknown, but evidence links it to bacteria belonging to the normal colonic microbiota. The aims of this study were to characterize bacteria colonizing the rectal epithelium, and to investigate whether significant differences existed in UC. Rectal biopsy specimens were obtained via endoscopy from 9 patients with active colitis and 10 patients without inflammatory bowel disease. Complex bacterial communities colonized the rectal mucosa in all subjects. Overall, 72 bacterial taxa (18 genera) were detected. Twenty species were common to both groups, but only differences in bifidobacteria were statistically significant (P=.005). Peptostreptococci were only detected in patients with UC. Microscopy showed that bacteria in mucosal biofilms often occurred in microcolonies. Interindividual variations in mucosal biofilms made it difficult to assign a role for specific bacteria in UC etiology. However, differences in bifidobacteria and peptostreptococci may implicate these organisms in this disease.

Chemopreventive role of folic acid in colorectal cancer.

Mortality from colorectal cancer, a leading cause of death in the U.S.A. and other western countries, has remained unchanged over the past 45 years. Therefore, the search for strategies to prevent the development and progression of colorectal cancer has markedly intensified. Chemoprevention is one such strategy. Accumulating evidence suggests that folic acid, a water soluble vitamin, could be an effective chemopreventive agent for colorectal cancer. Results from several studies have demonstrated that a diet deficient in folic acid may be associated with an increased risk of colonic neoplasia, whereas dietary supplementation of this nutrient may be chemopreventive. Although the mechanisms by which folic acid exerts its chemopreventive role in colorectal carcinogenesis remain to be fully elucidated, supplemental folic acid has been shown to arrest the loss of heterozygosity (LOH) of the tumor suppressor gene DCC (deleted in colorectal cancer) and to stabilize its protein in normal appearing rectal mucosa of patients with colorectal adenomas. Data from in vitro studies utilizing colon cancer cell lines suggest that supplemental folic acid or its metabolite 5-methyltetrahydrofolate (5-MTF) attenuates the expression and activation of EGF-receptor (EGFR) as well as proliferation of cells. The folic acid mediated reduction of EGFR function could partly be the result of suppression of EGFR gene through increased methylation of CpG sequences within its promoter.

Folic acid mediated attenuation of loss of heterozygosity of DCC tumor suppressor gene in the colonic mucosa of patients with colorectal adenomas

Loss of heterozygosity (LOH) and/or inactivation of tumor suppressor genes are implicated in the initiation and progression of many malignancies, including colorectal cancer. Although accumulating evidence suggests a chemopreventive role for folate in colorectal cancer, regulatory mechanisms are poorly understood. The primary objective of the current investigation was to determine whether folic acid would prevent LOH of the three tumor suppressor genes, deleted in colorectal cancer ( DCC), adenomatous polyposis coli ( APC) and p53 in macroscopically normal appearing rectal mucosa of patients with adenomatous polyps. In addition, the effect of folic acid on rectal mucosal proliferation was determined. Twenty patients were randomized in a double-blind study to receive either folic acid 5 mg once daily or identical placebo tablets for 1 year. Genomic DNA and total protein were extracted from the rectal mucosa at baseline and after 1 year of treatment and analyzed for LOH and protein levels of APC, DCC and p53 genes. In addition, paraffin-embedded mucosal specimens were analyzed for proliferating cell nuclear antigen (PCNA) immunoreactivity, as a measure of cellular proliferative activity. Folate supplementation prevented LOH of DCC gene in five out of five (100%) patients who demonstrated baseline heterozygosity, whereas two out of four (50%) placebo-treated patients with baseline heterozygosity demonstrated allelic loss. Mucosal protein levels of DCC were also reduced in 7 of 10 (70%) placebo-treated patients compared to only 2 of 10 (20%) of patients treated with folate. Levels increased, however, in eight and three patients in the folic acid and placebo groups, respectively ( P<0.02). Folic acid caused no change in allelic status of either APC or p53 gene. Folate supplementation caused a small, but not statistically significant, 16% reduction in mucosal proliferation, whereas placebo treatment resulted in a 88% ( P<0.05) increase in this parameter, when compared with the corresponding baseline values. Our results indicate that folic acid prevents an increase in proliferation and arrests LOH of DCC gene and also stabilizes its protein in normal appearing rectal mucosa of patients with colorectal adenomas. Taken together, our data suggest that one of the ways folate may exert its chemopreventive effect is by stabilizing certain tumor suppressor gene(s) and preventing further increases in proliferation.

Lactic acidosis in the rectal lumen of patients with septic shock measured by luminal equilibrium dialysis

Gut ischaemia may contribute to morbidity in sepsis, but little is known about the metabolic state of the gut mucosa in such patients. Nine patients with abdominal septic shock treated with norepinephrine, and ten healthy subjects, were subjected to equilibrium dialysis with a rectal balloon. pH, PCO(2) and concentrations of L-lactate were measured by auto-analyser. In rectal dialysis fluid from patients with septic shock, acidosis was present (pH 7.23, 95% CI 7.11-7.36) and concentrations of L-lactate were approximately five times greater than controls (2.5-5.8 vs 0.5-1.2 mmol litre(-1)). The lactate concentration was related to the dose of norepinephrine (P<0.001). In contrast, values of dialysate PCO(2) did not differ significantly between patients and controls (6.4-11.0 vs 8.9-13.8 kPa). The results suggest that, either lactic acidosis in rectal mucosa is related to shock severity, or that norepinephrine causes mucosal ischaemia. In any case, metabolic dysfunction is present in the rectal mucosa in patients with abdominal septic shock treated with norepinephrine.

Nonsteroidal anti-inflammatory drugs, apoptosis, and colorectal adenomas

Background & Aims: Observational studies indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of colorectal neoplasia. The mechanism of this effect could be via modification of apoptotic activity in colonic mucosa. We examined grossly normal rectal mucosa in patients with adenomas and adenoma-free controls to assess the associations between NSAID use, adenomatous polyps, and apoptosis. Methods: Study participants were drawn from consecutive patients who underwent colonoscopy between August, 1998, and February, 2000. Biopsy specimens were taken from normal-appearing rectal mucosa 10 cm from the anal verge. Apoptosis was scored from coded, H&E-stained sections using morphologic methods. Proliferation was scored using whole crypt mitotic counts. Univariate and multivariate regression analyses were conducted to estimate crude and adjusted odds ratios (ORs). Results: There were 226 patients with adenomas and 493 adenoma-free controls. After adjusting for sex, age, race, and body mass index (BMI), individuals in the highest tertile of regular NSAID use were substantially less likely to have adenomas (OR 0.4; 95% CI: 0.2–0.7) compared with occasional or nonusers. Similarly, compared with the lowest tertile, persons in the highest tertile of rectal mucosal apoptotic activity were much less likely to have adenomas (OR 0.12; 95% CI: 0.07–0.20). NSAID use and apoptotic activity were not correlated (r = 0.10). Mucosal proliferation was not related to adenomas or NSAID use. Conclusions: Our observations suggest that NSAID use and higher levels of mucosal apoptosis are independently associated with a lower prevalence of adenomas. The study shows a strong field effect for apoptosis.GASTROENTEROLOGY 2002;123:1770-1777

Allergic colitis: clinical and morphological aspects in infants with rectal bleeding

Recent studies indicate the importance of eosinophilis infiltrated in the rectal mucous which jointly with the clinical features can serve to establish the diagnostic of allergic colitis. To describe prospectively, the clinical features and morphological abnormalities of the rectal mucosa in patients with rectal bleeding and clinical diagnosis of cow's milk allergy. Clinical features of 20 infants under 6 months of age were described. Morphological findings in rectal mucosa were compared with control group, with suspicion of congenital megacolon. The mean age of the patients was 97 +/- 47 days, rectal bleeding started before 120 days in 85% of them; 40% were breastfed, 60% cow's milk formula or both. The most striking morphological feature, in 18 patients, was eosinophilic infiltration in the rectal mucosa. There was a significant statistical difference when these values were compared with control group. The increased number of eosinophils in the rectal mucosa represent the most important characteristic of allergic colitis, in patients under 6 months, with rectal bleeding, when breastfed, cow's milk formula or both.

Epithelial proliferation and ras p21 oncoprotein expression in rectal mucosa of patients with ulcerative colitis.

In ulcerative colitis (UC), epithelial proliferation plays a role in crypt repair and neoplastic evolution. Proliferative status is predominantly connoted in active disease, but not defined in remission. Histologically, remission is characterized by normalization of the picture or development of atrophy. Mutation of the ras oncogene is involved in intestinal carcinogenesis. Aim of this work was to assess the proliferative pattern of rectal epithelium in UC during disease activity and in remission and correlate it with ras oncoprotein p21. The study was performed retrospectively in rectal biopsies from four groups each of 10 patients: active ulcerative colitis (AUC), remission with a normal histology (RUC), remission with rectal atrophy (ARUC), and irritable bowel syndrome (C, control group). In all, immunohistostain was employed to evaluate the proliferation cell nuclear antigen labeling index (PCNA LI) and ras p21. Statistical analysis was performed by ANOVA and Student-Neumann-Keuls tests. PCNA LI was significantly higher in AUC and ARUC than in RUC and C. Positive cells were predominant in the lower zone of crypts in RUC and C, while a significant expression of PCNA was also observed in the upper areas in AUC and ARUC. Oncoprotein p21 was expressed on the apical surface of the epithelium in 3/10 AUC patients, in all 10 ARUC patients and in none of RUC and C. The persistently increased epithelial proliferation associated with ras p21 expression in ARUC may be due to the action of an abnormal, mutated ras gene that could play a role in UC-related tumorigenesis.