El presente trabajo, titulado “ESTUDIO DESCRIPTIVO DE EXÁMENES COLONOSCÓPICOS DEL 2000 AL 2003 EN EL HOSPITAL EsSALUD LA MOLINA”, es aun estudio descriptivo y retrospectivo, que incluyó el 100% de pacientes atendidos en el periodo de referencia, en el servicio de Gastroenterología del Hospital de EsSalud Carlos Alcántara Butterfield en la Molina; los pacientes del estudio fueron sometidos a colonoscopia durante el periodo comprendido entre los años 2000 a 2003, por la presencia de signos o síntomas de sospecha de patología de colón. El objetivo del presente estudio fue describir las características epidemiológicas y clínicas de la población estudiada, justificado por la inexistencia de estudios previos sobre la patología de colon en el Hospital referido. El estudio es un aporte, para mejorar el conocimiento de la patología de colon, en la población atendida; así mismo permitirá mejorar los procesos de diagnóstico en la población asegurada, describiendo algunos factores de riesgo asociados a dicha patología, que podrían ser estudiados posteriormente. También constituye una herramienta de análisis de los procesos diagnósticos de la patología de colon en el servicio, con la finalidad de mejorarlos, para beneficio del paciente asegurado.

Memoria para optar al título profesional de Bioquímico / El síndrome de intestino irritable (SII) es un trastorno funcional digestivo caracterizado por la presencia de dolor abdominal asociado a alteraciones del hábito intestinal. Si bien su fisiopatología no ha sido dilucidada completamente, se reconoce la existencia de un desequilibrio del eje cerebro-intestino, que afecta diversas funciones intestinales, entre ellas el aumento de la permeabilidad paracelular y la activación de células inmunes. La elevada activación de mastocitos se asocia a aumento de la permeabilidad intestinal debido a alteraciones en la organización de la unión estrecha (UE), mecanismo mediado por la activación de PAR-2 (receptor activado por proteasa-2) por triptasa. La proteína inmuno-moduladora Bcl-3 (B-cell leukemia/lymphoma-3) es un regulador transcripcional de genes activados por NF-κB, entre ellos los que regulan la UE. En este trabajo se proponen las siguientes hipótesis: 1) En pacientes con SII, existe una pérdida de la función de barrera intestinal asociada a un aumento en la expresión de Bcl- 3, a una elevada activación de mastocitos y a alteraciones de la unión estrecha epitelial; 2) La expresión de Bcl-3, es inducida por triptasa, mediante la activación de PAR-2, afectando el estado de la unión estrecha en líneas celulares de epitelio intestinal. Para ello, muestras de mucosa ileal y colónica de pacientes con SII y SC (sujetos controles) fueron recolectadas. En ellas se evaluó la expresión de Bcl-3, mediante q-PCR, western blot e inmunofluorescencia indirecta (IFI); el número de mastocitos y su grado de activación, por IFI y microscopía electrónica de transmisión (TEM); y las alteraciones de la UE, mediante IFI y TEM. El efecto de triptasa sobre la expresión de Bcl-3 y las alteraciones en la UE fueron evaluadas in vitro, en líneas celulares DLD-1 y Caco-2, mediante western blot e IFI. Los resultados evidenciaron una elevada expresión de Bcl-3 un aumento en el número y actividad de mastocitos, alteraciones en la distribución y expresión de ZO-1 en mucosa y alteración de la arquitectura de la UE epitelial intestinal en pacientes con SII en comparación con SC. Nuestros resultados in vitro evidenciaron que la expresión de Bcl-3 fue inducida por triptasa, a través de la activación de PAR-2, induciendo este estimulo alteraciones en la distribución de proteínas de la UE. Nuestros hallazgos sugieren que en el SII, la proteína Bcl-3 actuaría como un factor intermediario de las alteraciones de la UE epitelial inducida por la activación de triptasa/PAR-2. Futuros estudios dirigidos estudiar con profundidad este mecanismo permitirán contribuir a la fisiopatología del SII, en miras de un nuevo marcador diagnostico y blanco terapéutico / Irritable bowel syndrome (IBS) is a digestive functional disorder characterized by the presence of abdominal pain associated with alterations of the intestinal habit. Although its pathophysiology has not been fully elucidated, the existence of an imbalance of the brainintestine axis is recognized, which affects various intestinal functions, among them the increase in paracellular permeability and the activation of immune cells. The high activation of mast cells is associated with increased intestinal permeability due to alterations in the organization of the tight junction (TJ), a mechanism mediated by the activation of PAR-2 (receptor activated by protease-2) by tryptase. The Bcl-3 immunomodulating protein (B-cell leukemia / lymphoma-3) is a transcriptional regulator of genes activated by NF-κB, including those that regulate the TJ. In this work, the following hypotheses are proposed: 1) In patients with IBS, there is a loss of intestinal barrier function associated with an increase in the expression of Bcl-3, a high activation of mast cells and alterations of the epithelial tight junction ; 2) The expression of Bcl-3 is induced by tryptase, through the activation of PAR-2, affecting the state of the tight junction in intestinal epithelial cell lines.. To do this, samples of ileal and colonic mucosa from patients with IBS and CS (control subjects) were collected. In them, the expression of Bcl-3 was evaluated by means of q-PCR, western blot and indirect immunofluorescence (IFI); the number of mast cells and their degree of activation, by IFI and transmission electron microscopy (TEM); and the alterations of the TJ, through IFI and TEM. The effect of tryptase on the expression of Bcl-3 and the alterations in the EU were evaluated in vitro, in cell lines DLD-1 and Caco-2, by means of western blot and IFI. The results showed a high expression of Bcl-3 an increase in the number and activity of mast cells, alterations in the distribution and expression of ZO-1 in mucosa and alteration of the architecture of the intestinal epithelial TJ in patients with IBS compared to CS . Our in vitro results showed that the expression of Bcl-3 was induced by tryptase, through the activation of PAR-2, inducing this stimulation alterations in the distribution of proteins of the TJ. Our findings suggest that in IBS, the Bcl-3 protein would act as an intermediary factor of epithelial TJ alterations induced by the activation of tryptase / PAR-2. Future studies aimed at studying in depth this mechanism will allow contributing to the pathophysiology of IBS, in view of a new diagnostic marker and therapeutic target

No description available.

Aberrant methylation of CpG island promoters is a frequent observation in cancer and is known to affect many genes, including tumour suppressor genes. Genes with methylated promoters are usually repressed and inactive, and there is good evidence that most genes that become methylated in cancer are already repressed in the normal tissues from which tumours arise. However, the methylation of some genes appears to arise at previously active loci, suggesting either a stochastic epigenetic event or that these genes are somehow predisposed to becoming methylated. The DNA mismatch repair gene MLH1 is expressed in normal colonic epithelial cells but methylated and down-regulated in some sporadic mismatch repair-deficient colon tumours. These tumours are almost invariably associated with the simultaneous methylation of multiple cancer-specific loci, termed the CpG island methylator phenotype (CIMP) and an activating mutation of BRAF (V600E), raising the possibility that a hypermethylator phenotype may arise in cancer in direct association with a specific genetic alteration. The possibility that MLH1-deficiency caused BRAF mutation was discounted as genetic deficiency of MLH1 is not associated with BRAFV600E. I explored the possibility that BRAFV600E might induce MLH1 methylation but found no evidence in support of this. I then focused on factors that might mediate CIMP gene methylation, of which MLH1 methylation is known to be a part. Bioinformatic analysis of the genes methylated in BRAFV600E colon tumours indicated a significant enrichment in binding sites for the transcription factor MAZ (MYC-associated zinc finger protein). I hypothesised that loss of MAZ might lead to MLH1 down-regulation and its subsequent methylation. In this thesis I provide evidence that both MAZ and MLH1 expression are deregulated during normal colonic epithelial differentiation. The down-regulation of MAZ by RNA interference led to a reduction in MLH1 expression and methylation of its promoter. I speculate that MLH1 methylation may be associated with BRAF mutation because transformation by BRAFV600E allows progenitor cells to undergo a degree of differentiation whilst maintaining their malignant proliferation. I speculate that it is during this process of differentiation that MLH1 becomes susceptible to methylation.

archives@tulane.edu / 1 / Margaret Brooks

Includes bibliographical references (leaves 136-156) Two novel in vitro preparations were developed from which recordings were made from colonic afferents in the rat and mouse.

We have previously shown that dietary fish oil and fiber, particularly the highly-fermentable pectin, are protective against colon cancer in a rat model of carcinogenesis. Therefore, based upon the current body of literature and our previous experimental findings, we hypothesized that one mechanism by which dietary fish oil+pectin suppress the promotion stage of colon cancer is through butyrate, the fermentation product of fiber, targeting (in particular) the p21Waf1/Cip1 gene and, via targeted histone hyperacetylation, inducing its expression. We found that dietary butyrate supplementation increased the concentration of fecal butyrate (mole %) in the distal colon, and that this increase corresponded to an increase in histone H4 acetylation. Similarly, diets supplemented with butyrate increased p21Waf1/Cip1 expression despite azoxymethane (AOM) treatment, which was not seen in non-butyrate supplemented diets. Furthermore, fish oil+butyrate diets resulted in the highest levels of apoptosis and the lowest levels of ACF, while corn oil+butyrate diets resulted in the lowest levels of apoptosis and the highest levels of ACF. Thus, it appears that the protective effect of fish oil+butyrate is due to the unique properties of fish oil, providing an environment in which butyrate’s enhancement of histone acetylation and p21 expression are pro-apoptotic, thereby diminishing pre-neoplastic ACF development.

La voie de signalisation Hedgehog (HH) est impliquée dans le développement du tractus gastro-intestinal chez de nombreuses espèces. Elle est importante chez ladulte en participant au maintien de lhoméostasie de lépithélium intestinal. Récemment la suractivation de la voie HH a été mise en évidence dans de nombreux cancers dont ceux du tractus gastro-intestinal tels que les cancers de lestomac et du pancréas. Au cours de ce travail, nous nous sommes intéressés à la voie de signalisation HH dans les cancers du côlon. Lexpression des membres principaux de la voie HH a dabord été caractérisée dans sept lignées cellulaires de cancers du côlon (Colo205, Colo320, HCT116, HT29, WiDr, SW480, Caco-2). Labsence dexpression de certains membres clés de la voie indique que celle-ci nest pas activée, de façon autocrine, dans les lignées cellulaires. Cette observation est également appuyée par des expériences réalisées en traitant les cellules à la cyclopamine, inhibiteur de la voie HH. Enfin GLI1, facteur de transcription mimant une activation de la voie HH, a été surexprimé stablement dans les cellules HCT116. Nous avons pu montrer que lactivation de la voie HH induisait lexpression du gène BMP4, gène cible de la voie HH lors de lembryogenèse intestinale, ainsi que lactivité phosphatase alcaline, marqueur de différenciation du côlon. Ces résultats suggèrent que la voie de signalisation HH nest pas activée de façon autocrine dans les cancers du côlon mais semble plutôt associée à la différenciation des cellules du côlon.

In order to test the dietary effects of bioactive compounds present in whole grains, we decided to observe the effect of varying types of sorghum bran on colon cancer promotion. We used 40 rats consuming diets containing 6% fiber from either cellulose or bran from white (contains phenolic acids), brown (contains tannins), or black (contains anthocyanins) sorghum (n=10). Diets were fed for 10 wk, during which two azoxymethane (AOM) injections (15 mg/kg BW) were administered in wk 3 and 4. We observed that the total number of aberrant crypts (AC) and high multiplicity aberrant crypt foci (HMACF) were lower in rats consuming black (p < 0.04) and brown (p < 0.006) sorghum diets when compared to the cellulose diet, and that these decreases were an inverse function of diet antioxidant activity (ABTS). These observations led us to evaluate the effect of these diets on endogenous enzymatic activities (superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx), redox status as measured by reduced and oxidized glutathione, and cell cycle processes, proliferation and apoptosis, in the rat colon. Total SOD activity was higher (p < 0.04) in rats consuming black sorghum when compared to all other diets. A similar, but not significant, trend occurred in mitochondrial SOD. The white sorghum diet had enhanced (p < 0.02) CAT activity compared to the cellulose diet, but the black and brown sorghum diets were intermediate. Finally, all sorghum diets suppressed GPx activity relative to cellulose (p < 0.04). However, no changes were seen in levels of reduced and oxidized glutathione or the ratio of the two. The black sorghum fed rats had a lower proliferative index (p < 0.01) and zone (p < 0.04) compared to cellulose; brown and white sorghum rats were intermediate. Apoptotic index was highest in brown sorghum rats compared to cellulose (p < 0.03), while other sorghum diets were intermediate. These data suggest that the suppression of AC and HMACF formation in rats consuming sorghum bran may have resulted through the differential actions of the sorghum brans on endogenous antioxidant enzymes, which may affect colonocyte proliferation and apoptosis.

We have previously shown that dietary fish oil and the fiber pectin protect against colon cancer in rats by increasing apoptosis induced by reactive oxygen species (ROS) at the initiation stage of tumorigenesis. We hypothesized that fish oil would incorporate into the cardiolipin of colonic mitochondrial membranes, creating an environment in which butyrate, a fermentation product of pectin, would also increase ROS and lead to apoptosis, as evidenced by decreased mitochondrial membrane potential (MMP), enhanced caspase-3 activity and cytochrome c translocation from the mitochondria, thus protecting against colon cancer by removing DNA damaged cells at the promotion stage of carcinogenesis. Sixty rats were provided a diet containing 15% corn or fish oil for 11 wk and injected with azoxymethane (AOM) or saline at wk 3 and 4. At wk 11, colonocytes were exposed to +/- butyrate ex vivo for 30 or 60 min. ROS and MMP were measured using fluorescence microscopy, and cytochrome c concentration and caspase-3 activity were measured using ELISA assays. Cardiolipin fatty acid enrichment was measured via TLC and GC. Butyrate increased ROS (p<0.0001) regardless of diet or treatment group. In colonic crypts from fish oilconsuming rats, butyrate reduced MMP (p=0.05). However, butyrate had no effect on MMP if the rats were consuming corn oil. In colonocytes from rats consuming fish oil, butyrate decreased mitochondrial cytochrome c (11%; p=0.02) concomitant with an increase in caspase-3 activity (17%; p=0.04) in the distal colon. In fish oil-fed animals, the n-3 fatty acids DHA and EPA were incorporated into cardiolipin at the expense of n-6 fatty acids. Regression analysis revealed a positive relationship between DHA (R=0.49, p=0.03) and EPA (R=0.59, p=0.02) and cytosolic cytochrome c content. As the percentage of DHA and EPA in the cardiolipin increased, the level of cytochrome c in the cytosol increased. These relationships were not seen in rats consuming corn oil and suggest that these results, induced only by the combination of butyrate with fish oil, may lead to increased apoptosis at the promotion stage of colon carcinogenesis via a mitochondria-mediated mechanism.