997 resultados para colon disease
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Abstract: Since ancient times, people have attributed a variety of health benefits to moderate consumption of fermented beverages such as wine and beer, often without any scientific basis. There is evidence that excessive or binge alcohol consumption is associated with increased morbidity and mortality, as well as with work related and traffic accidents. On the contrary, at the moment, several epidemiological studies have suggested that moderate consumption of alcohol reduces overall mortality, mainly from coronary diseases. However, there are discrepancies regarding the specific effects of different types of beverages (wine, beer and spirits) on the cardiovascular system and cancer, and also whether the possible protective effects of alcoholic beverages are due to their alcoholic content (ethanol) or to their non-alcoholic components (mainly polyphenols). Epidemiological and clinical studies have pointed out that regular and moderate wine consumption (one to two glasses a day) is associated with decreased incidence of cardiovascular disease (CVD), hypertension, diabetes, and certain types of cancer, including colon, basal cell, ovarian, and prostate carcinoma. Moderate beer consumption has also been associated with these effects, but to a lesser degree, probably because of beer"s lower phenolic content. These health benefits have mainly been attributed to an increase in antioxidant capacity, changes in lipid profiles, and the anti-inflammatory effects produced by these alcoholic beverages. This review summarizes the main protective effects on the cardiovascular system and cancer resulting from moderate wine and beer intake due mainly to their common components, alcohol and polyphenols.
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Reactive oxygen species are now widely recognized as important players contributing both to cell homeostasis and the development of disease. In this respect nitric oxide (NO) is no exception. The discussion here will center on regulation of the inducible form of nitric oxide synthase (iNOS) for two reasons. First, only iNOS produces micromolar NO concentrations, amounts that are high by comparison with the picomolar to nanomolar concentrations resulting from Ca2(+)-controlled NO production by endothelial eNOS or neuronal nNOS. Second, iNOS is not constitutively expressed in cells and regulation of this isoenzyme, in contrast to endothelial eNOS or neuronal nNOS, is widely considered to occur at the transcriptional level only. In particular, we were interested in the possibility that caveolin-1, a protein that functions as a tumor suppressor in colon carcinoma cells (Bender et al., 2002; this issue), might regulate iNOS activity. Our results provide evidence for the existence of a post-transcriptional mechanism controlling iNOS protein levels that involves caveolin-1-dependent sequestration of iNOS within a detergent-insoluble compartment. Interestingly, despite the high degree of conservation of the caveolin-1 scaffolding domain binding motif within all NOS enzymes, the interaction detected between caveolin-1 and iNOS in vitro is crucially dependent on presence of a caveolin-1 sequence element immediately adjacent to the scaffolding domain. A model is presented summarizing the salient aspects of these results. These observations are important in the context of tumor biology, since down-regulation of caveolin-1 is predicted to promote uncontrolled iNOS activity, genotoxic damage and thereby facilitate tumor development in humans.
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An increased expression of nitric oxide synthase (NOS) has been observed in human colon carcinoma cell lines as well as in human gynecological, breast, and central nervous system tumors. This observation suggests a pathobiological role of tumor-associated NO production. Hence, we investigated NOS expression in human colon cancer in respect to tumor staging, NOS-expressing cell type(s), nitrotyrosine formation, inflammation, and vascular endothelial growth factor expression. Ca2+-dependent NOS activity was found in normal colon and in tumors but was significantly decreased in adenomas (P < 0.001) and carcinomas (Dukes' stages A-D: P < 0.002). Ca2+-independent NOS activity, indicating inducible NOS (NOS2), is markedly expressed in approximately 60% of human colon adenomas (P < 0.001 versus normal tissues) and in 20-25% of colon carcinomas (P < 0.01 versus normal tissues). Only low levels were found in the surrounding normal tissue. NOS2 activity decreased with increasing tumor stage (Dukes' A-D) and was lowest in colon metastases to liver and lung. NOS2 was detected in tissue mononuclear cells (TMCs), endothelium, and tumor epithelium. There was a statistically significant correlation between NOS2 enzymatic activity and the level of NOS2 protein detected by immunohistochemistry (P < 0.01). Western blot analysis of tumor extracts with Ca2+-independent NOS activity showed up to three distinct NOS2 protein bands at Mr 125,000-Mr 138,000. The same protein bands were heavily tyrosine-phosphorylated in some tumor tissues. TMCs, but not the tumor epithelium, were immunopositive using a polyclonal anti-nitrotyrosine antibody. However, only a subset of the NOS2-expressing TMCs stained positively for 3-nitrotyrosine, which is a marker for peroxynitrite formation. Furthermore, vascular endothelial growth factor expression was detected in adenomas expressing NOS2. These data are consistent with the hypothesis that excessive NO production by NOS2 may contribute to the pathogenesis of colon cancer progression at the transition of colon adenoma to carcinoma in situ.
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PURPOSE: The MOSAIC (Multicenter International Study of Oxaliplatin/Fluorouracil/Leucovorin in the Adjuvant Treatment of Colon Cancer) study has demonstrated 3-year disease-free survival (DFS) and 6-year overall survival (OS) benefit of adjuvant oxaliplatin in stage II to III resected colon cancer. This update presents 10-year OS and OS and DFS by mismatch repair (MMR) status and BRAF mutation. METHODS: Survival actualization after 10-year follow-up was performed in 2,246 patients with resected stage II to III colon cancer. We assessed MMR status and BRAF mutation in 1,008 formalin-fixed paraffin-embedded specimens. RESULTS: After a median follow-up of 9.5 years, 10-year OS rates in the bolus/infusional fluorouracil plus leucovorin (LV5FU2) and LV5FU2 plus oxaliplatin (FOLFOX4) arms were 67.1% versus 71.7% (hazard ratio [HR], 0.85; P = .043) in the whole population, 79.5% versus 78.4% for stage II (HR, 1.00; P = .980), and 59.0% versus 67.1% for stage III (HR, 0.80; P = .016) disease. Ninety-five patients (9.4%) had MMR-deficient (dMMR) tumors, and 94 (10.4%) had BRAF mutation. BRAF mutation was not prognostic for OS (P = .965), but dMMR was an independent prognostic factor (HR, 2.02; 95% CI, 1.15 to 3.55; P = .014). HRs for DFS and OS benefit in the FOLFOX4 arm were 0.48 (95% CI, 0.20 to 1.12) and 0.41 (95% CI, 0.16 to 1.07), respectively, in patients with stage II to III dMMR and 0.50 (95% CI, 0.25 to 1.00) and 0.66 (95% CI, 0.31 to 1.42), respectively, in those with BRAF mutation. CONCLUSION: The OS benefit of oxaliplatin-based adjuvant chemotherapy, increasing over time and with the disease severity, was confirmed at 10 years in patients with stage II to III colon cancer. These updated results support the use of FOLFOX in patients with stage III disease, including those with dMMR or BRAF mutation.
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PURPOSE: Prospective-retrospective assessment of theTOP1gene copy number andTOP1mRNA expression as predictive biomarkers for adjuvant irinotecan in stage II/III colon cancer. EXPERIMENTAL DESIGN: Formalin-fixed, paraffin-embedded tissue microarrays were obtained from an adjuvant colon cancer trial (PETACC3) where patients were randomized to 5-fluorouracil/folinic acid with or without additional irinotecan.TOP1copy number status was analyzed by fluorescencein situhybridization (FISH) using aTOP1/CEN20 dual-probe combination.TOP1mRNA data were available from previous analyses. RESULTS: TOP1FISH and follow-up data were obtained from 534 patients.TOP1gain was identified in 27% using a single-probe enumeration strategy (≥4TOP1signals per cell) and in 31% when defined by aTOP1/CEN20 ratio ≥ 1.5. The effect of additional irinotecan was not dependent onTOP1FISH status.TOP1mRNA data were available from 580 patients with stage III disease. Benefit of irinotecan was restricted to patients characterized byTOP1mRNA expression ≥ third quartile (RFS: HRadjusted, 0.59;P= 0.09; OS: HRadjusted, 0.44;P= 0.03). The treatment byTOP1mRNA interaction was not statistically significant, but in exploratory multivariable fractional polynomial interaction analysis, increasingTOP1mRNA values appeared to be associated with increasing benefit of irinotecan. CONCLUSIONS: In contrast to theTOP1copy number, a trend was demonstrated for a predictive property ofTOP1mRNA expression. On the basis ofTOP1mRNA, it might be possible to identify a subgroup of patients where an irinotecan doublet is a clinically relevant option in the adjuvant setting of colon cancer.Clin Cancer Res; 22(7); 1621-31. ©2015 AACR.
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Manometric and pharmacological tests have shown that motor abnormalities may occur in the non-dilated colons of chagasic patients. In order to investigate the presence of abnormalities of colonic function in constipated patients with Chagas disease (ChC) without megaesophagus or megacolon, studies of total and segmental colonic transit time with radiopaque markers were performed on 15 ChC patients, 27 healthy volunteers and 17 patients with idiopathic constipation (IC). The values obtained for the control group were similar to those reported in the literature (total colonic time: 34.1 ± 15.6 h; right colon: 9.9 ± 7.3 h; left colon: 10.8 ± 10 h, and rectosigmoid: 12.6 ± 9.9 h). Colonic transit time data permitted us to divide both IC and ChC patients into groups with normal transit and those with slow colonic transit. Colonic inertia was detected in 41% of IC patients and in 13% of ChC patients; left colon isolated stasis (hindgut dysfunction) was detected in 12% of IC patients and 7% of ChC patients, and outlet obstruction was detected in 6% of IC patients and 7% of ChC patients. There were no significant differences in total or segmental colonic transit times between slow transit IC and slow transit ChC patients. In conclusion, an impairment of colonic motility was detected in about 30% of constipated patients with Chagas disease without megaesophagus or megacolon. This subgroup of patients presented no distinctive clinical feature or pattern of colonic dysmotility when compared to patients with slow transit idiopathic constipation.
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The objective of the present study was to perform a spectral analysis of the electrical activity of the left colon of patients with hepatosplenic schistosomiasis. Thirty patients were studied, divided into 2 groups: group A was composed of 14 patients (9 males and 5 females) with hepatosplenic schistosomiasis and group B was composed of 16 female patients without schistosomiasis mansoni. Three pairs of electrodes were implanted in the left colon at the moment of the surgical treatment. The signals of the electric activity of the colon were captured after postoperative recovery from the ileus and fed into a computer by means of a DATAQ data collection system which identified and captured frequencies between 0.02 and 10 Hz. Data were recorded, stored and analyzed using the WINDAQ 200 software. For electrical analysis, the average voltage of the electrical wave in the three electrodes of all patients, expressed as millivolts (mV), was considered, together with the maximum and minimum values, the root mean square (RMS), the skewness, and the results of the fast Fourier transforms. The average RMS of the schistosomiasis mansoni patients was 284.007 mV. During a long period of contraction, the RMS increased in a statistically significant manner from 127.455 mV during a resting period to 748.959 mV in patients with schistosomiasis mansoni. We conclude that there were no statistically significant differences in RMS values between patients with schistosomiasis mansoni and patients without the disease during the rest period or during a long period of contraction.
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Intermediate filament keratins (K) play a pivotal role in protein targeting and epithelialcytoprotection from stress as evidenced by keratin mutations predisposing to human liver and skin diseases and possibly inflammatory bowel disease (IBD). The K8-null (K8-/-) mice exhibit colonic phenotype similar to IBD and marked spontaneous colitis, epithelial hyperproliferation, decreased apoptosis, mistargeting of proteins leading to defective ion transport and diarrhea. The K8-heterozygote (K8+/-) mouse colon appears normal but displays a defective sodium (Na+) and chloride (Cl-) transport similar to, but milder than K8-/-. Characterization of K8+/- colon revealed ~50% less keratins (K7, K8, K19, K20) compared to K8 wild type (K8+/+). A similar ~50% decrease was seen in K8+/- mRNA levels as compared to K8+/+, while the mRNA levels for the other keratins were unaltered. K8+/- keratins were arranged in a normal colonic crypt expression pattern, except K7 which was expressed at the top of crypts in contrast to K8+/+. The K8+/- colon showed mild hyperplasia but no signs of inflammation and no resistance to apoptosis. Experimental colitis induced by using different concentrations of dextran sulphate sodium (DSS) showed that K8+/- mice are slightly more sensitive to induced colitis and showed a delayed recovery compared to K8+/+. Hence, the K8+/- mouse with less keratins and without inflammation, provided a novel model to study direct molecular mechanisms of keratins in intestinal homeostasis and ion transport. Different candidate ion transporters for a possible role in altered ion transport seen in the K8-/- and K8+/- mouse colon were evaluated. Besides normal levels of CFTR, PAT-1 and NHE-3, DRA mRNA levels were decreased 3-4-fold and DRA protein nearly entirely lost in K8-/- caecum, distal and proximal colon compared to K8+/+. In K8+/- mice, DRA mRNA levels were unaltered while decreased DRA protein level and patchy distribution was detected particularly in the proximal colon and as compared to K8+/+. DRA was similarly decreased when K8 was knocked-down in Caco-2 cells, confirming that K8 levels modulate DRA levels in an inflammation-independent manner. The dramatic loss of DRA in colon and caecum of K8-/- mice was responsible for the chloride transport defect. The milder ion transport in K8+/- colon might be related to DRA suggesting a role for K8 in regulation of DRA expression and targeting. The current study demonstrates the importance of keratins in stress protection and cell signaling. Furthermore, we have also successfully developed a novel, simple, fast, cost effective, non-invasive in vivo imaging method for the early diagnosis of murine colitis with specificity for both genetic and experimental colitis. The said modality provides continuous measurements of reactive oxygen and nitrogen species (RONS) and minimizes the use of an increased number of experimental animals by using a luminal derivative chemiluminescent probe, L-012 which provides a cost-effective tool to study the level and longitudinal progression of colitis.
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Keratins (K) are cytoskeletal proteins mainly expressed in the epithelium and constitute the largest subgroup of intermediate filaments (IFs). Simple epithelial keratins (SEKs) K7-K8 and K18-K20 are the major IF elements in the colon. SEK mutations are known to cause around 30 human diseases, mainly affecting liver and skin. However, so far no strong associations between K8 mutations and the development of human colitis have been found. The keratin contribution to colonic health comes from the K8 knock-out (K8-/-) mouse model, which develops an early chronic inflammation and hyperproliferation in the colon. The aim of this thesis was to investigate how keratins contribute to intestinal health and disease mainly by the experimental analysis using the K8-/- mouse colon and cell culture models. The work described here is divided into three studies. The first study revealed involvement of keratins in Notch1 signaling, which is the master regulator of cell fate in the colon. Immunoprecipitation and immunostaining, both in vitro and in vivo showed that K8 binds and co-localizes with Notch1. Interestingly, overexpression of keratins enhanced Notch1 levels and stabilized Notch intracellular domain (NICD), leading to higher activity of Notch signaling. The dramatic decrease in Notch activity in the K8-/- colon resulted in a differentiation shift towards goblet and enteroendocrine cells. The second study focused on the involvement of keratins in colitis-associated cancer (CAC). Although, the K8-/- inflamed colon did not develop colorectal cancer (CRC) spontaneously, it was dramatically more susceptible to induced CRC in two CRC models: azoxymethane (AOM) and multiple intestinal neoplasia (ApcMin/+). To understand how the loss of K8 contributes to CAC, the epithelial inflammasome signaling pathway was analyzed. The released component of active inflammasome, cleaved caspase-1 and its downstream protein, interleukin (IL)-18, were significantly increased in K8-/- and K8-/-ApcMin/+ colons. The inflammasome pathway has recently been suggested to control the levels of IL-22 binding protein (IL-22BP), which is a negative regulator of IL-22 activity. Interestingly, the activated inflammasome correlated with an upregulation of IL-22 and a complete loss of IL-22BP in the K8-null colons. The activation of IL-22 was confirmed by increased levels of downstream signaling, which is phosphorylated signal transducer and activator of transcription 3 (P-STAT3), a transcription factor promoting proliferation and tissue regeneration in the colon. The objective of the third study, was to examine the role of keratins in colon energy metabolism. A proteomic analysis identified mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) as the major ownregulated protein in the K8-/- colonocytes. HMGCS2 is the rate-limiting enzyme in ketogenesis, where energy from bacterially produced short chain fatty acids (SCFAs), mainly butyrate, is converted into ketone bodies in colonic epithelium. Lower levels and activity of HMGCS2 in the K8-/- colon resulted in a blunted ketogenesis. The studies upstream from HMGCS2, identified decreased levels of the SCFA-transporter monocarboxylate transporter 1 (MCT1), which led to increased SCFA content in the stool suggesting impaired butyrate transport through the colonic epithelium. Taken together, the results of the herein thesis indicate that keratins are essential regulators of colon homeostasis, in particular epithelial differentiation, tumorigenesis and energy metabolism.
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Most human genes undergo alternative splicing and loss of splicing fidelity is associated with disease. Epigenetic silencing of hMLH 1 via promoter cytosine methylation is causally linked to a subset of sporadic non-polyposis colon cancer and is reversible by 5-aza-2' -deoxycytidine treatment. Here I investigated changes in hMLHI mRNA splicing profiles in normal fibroblasts and colon cancer-derived human cell lines. I established the types and frequencies of hMLHI mRNA transcripts generated under baseline conditions, after hydrogen peroxide induced oxidative stress, and in acutely 5-aza-2' -deoxycytidine-treated and stably derepressed cancer cell lines. I found that hMLHI is extensively spliced under all conditions including baseline (50% splice variants), the splice variant distribution changes in response to oxidative stress, and certain splice variants are sensitive to 5- aza-2' -deoxycytidine treatment: Splice variant diversity and frequency of exon 17 skipping correlates with the level of hMLHI promoter methylation suggesting a link between promoter methylation and mRNA splicing.
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La captación de glucosa y su conversión en lactato juega un papel fundamental en el metabolismo tumoral, independientemente de la concentración de oxígeno presente en el tejido (efecto Warburg). Sin embrago, dicha captación varía de un tipo tumoral a otro, y dentro del mismo tumor, situación que podría depender de las características microambientales tumorales (fluctuaciones de oxígeno, presencia de otros tipos celulares) y de factores estresores asociados a los tratamientos. Se estudió el efecto de la hipoxia-reoxigenación (HR) y las radiaciones ionizantes (RI) sobre la captación de glucosa, en cultivos de líneas tumorales MCF-7 y HT-29, cultivadas de forma aislada o en cocultivo con la línea celular EAhy296. Se encontró que la captación de glucosa en HR es diferente para lo descrito en condiciones de hipoxia permanente y que es modificada en el cocultivo. Se identificaron poblaciones celulares dentro de la misma línea celular, de alta y baja captación de glucosa, lo que implicaría una simbiosis metabólica de la célula como respuesta adaptativa a las condiciones tumorales. Se evaluó la expresión de NRF2 y la translocación nuclear de NRF2 y HIF1a, como vías de respuesta a estrés celular e hipoxia. La translocación nuclear de las proteínas evaluadas explicaría el comportamiento metabólico de las células tumorales de seno, pero no de colon, por lo cual deben existir otras vías metabólicas implicadas. Las diferencias en el comportamiento de las células tumorales en HR en relación con hipoxia permitirá realizar planeaciones dosimétricas más dinámicas, que reevalúen las condiciones de oxigenación tumoral constantemente.
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The application of probiotics and prebiotics to the manipulation of the microbial ecology of the human colon has recently seen many scientific advances. The sequencing of probiotic genomes is providing a wealth of new information on the biology of these microorganisms. In addition, we are learning more about the interactions of probiotics with human cells and with pathogenic bacteria. An alternative means of modulating the colonic microbial community is by the use of prebiotic oligosaccharides. Increasing knowledge of the metabolism of prebiotics by probiotics is allowing us to consider specifically targeting such dietary intervention tools at specific populatiori groups and specific disease states. (c) 2005 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.
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Colorectal cancer is one of the most common cancers in Western countries. The World Health Organisation identifies diet as a critical risk factor in the development and progression of this disease and the protective role of high levels of fruit and vegetable consumption. Several studies have shown that apples contain several phenolic compounds that are potent anti-oxidants in humans. However, little is known about other beneficial properties of apple phenolics in cancer. We have used the HT29, HT115 and CaCo-2 cell lines as in vitro models to examine the effect of apple phenolics (0.01–0.1% apple extract) on key stages of colorectal carcinogenesis, namely; DNA damage (Comet assay), colonic barrier function (TER assay), cell cycle progression (DNA content assay) and invasion (Matrigel assay). Our results indicate that a crude extract of apple phenolics can protect against DNA damage, improve barrier function and inhibit invasion (p < 0.05). The anti-invasive effects of the extract were enhanced with twenty-four hour pretreatment of cells (p < 0.05). We have shown that a crude apple extract from waste, rich in phenolic compounds, beneficially influences key stages of carcinogenesis in colon cells in vitro.
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Coronary heart disease (CHD) is the leading cause of mortality in Western societies, affecting about one third of the population before their seventieth year. Over the past decades modifiable risk factors of CHD have been identified, including smoking and diet. These factors when altered can have a significant impact on an individuals' risk of developing CHD, their overall health and quality of life. There is strong evidence suggesting that dietary intake of plant foods rich in fibre and polyphenolic compounds, effectively lowers the risk of developing CHD. However, the efficacy of these foods often appears to be greater than the sum of their recognised biologically active parts. Here we discuss the hypothesis that beneficial metabolic and vascular effects of dietary fibre and plant polyphenols are due to an up regulation of the colon-systemic metabolic axis by these compounds. Fibres and many polyphenols are converted into biologically active compounds by the colonic microbiota. This microbiota imparts great metabolic versatility and dynamism, with many of their reductive or hydrolytic activities appearing complementary to oxidative or conjugative human metabolism. Understanding these microbial activities is central to determining the role of different dietary components in preventing or beneficially impacting on the impaired lipid metabolism and vascular dysfunction that typifies CHD and type 11 diabetes. This approach lays the foundation for rational selection of health promoting foods, rational target driven design of functional foods, and provides an essential thus-far, overlooked, dynamic to our understanding of how foods recognised as "healthy" impact on the human metabonome.
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Diverticular disease (DD) is an age-related disorder of the large bowel which may affect half of the population over the age of 65 in the UK. This high prevalence ranks it as one of the most common bowel disorders in western nations. The majority of patients remain asymptomatic but there are associated life-threatening co-morbidities, which, given the large numbers of people with DD, translates into a considerable number of deaths per annum. Despite this public health burden, relatively little seems to be known about either the mechanisms of development or causality. In the 1970s, a model of DD formulated the concept that diverticula occur as a consequence of pressureinduced damage to the colon wall amongst those with a low intake of dietary fiber. In this review, we have examined the evidence regarding the influence of ageing, diet, inflammation and genetics on DD development. We argue that the evidence supporting the barotrauma hypothesis is largely anecdotal. We have also identified several gaps in the knowledge base which need to be filled before we can complete