Francisco López-Köstner

Escherichia coli isolates from inflammatory bowel diseases patients survive in macrophages and activate NLRP3 inflammasome.

Crohns disease (CD) is a multifactorial pathology associated with the presence of adherent-invasive Escherichia coli (AIEC) and NLRP3 polymorphic variants. The presence of intracellular E. coli in other intestinal pathologies (OIP) and the role of NLRP3-inflammasome in the immune response activated by these bacteria have not been investigated. In this study, we sought to characterize intracellular strains isolated from patients with CD, ulcerative colitis (UC) and OIP, and analyze NLRP3-inflammasome role in the immune response and bactericidal activity induced in macrophages exposed to invasive bacteria. For this, intracellular E. coli isolation from ileal biopsies, using gentamicin-protection assay, revealed a prevalence and CFU/biopsy of E. coli higher in biopsies from CD, UC and OIP patients than in controls. To characterize bacterial isolates, pulsed-field gel electrophoresis (PFGE) patterns, virulence genes, serogroup and phylogenetic group were analyzed. We found out that bacteria isolated from a given patient were closely related and shared virulence factors; however, strains from different patients were genetically heterogeneous. AIEC characteristics in isolated strains, such as invasive and replicative properties, were assessed in epithelial cells and macrophages, respectively. Some strains from CD and UC demonstrated AIEC properties, but not strains from OIP. Furthermore, the role of NLRP3 in pro-inflammatory cytokines production and bacterial elimination was determined in macrophages. E. coli strains induced IL-1β through NLRP3-dependent mechanism; however, their elimination by macrophages was independent of NLRP3. Invasiveness of intracellular E. coli strains into the intestinal mucosa and IL-1β production may contribute to CD and UC pathogenesis.

Mutation spectrum in South American Lynch syndrome families

BackgroundGenetic counselling and testing for Lynch syndrome have recently been introduced in several South American countries, though yet not available in the public health care system.MethodsWe compiled data from publications and hereditary cancer registries to characterize the Lynch syndrome mutation spectrum in South America. In total, data from 267 families that fulfilled the Amsterdam criteria and/or the Bethesda guidelines from Argentina, Brazil, Chile, Colombia and Uruguay were included.ResultsDisease-predisposing mutations were identified in 37% of the families and affected MLH1 in 60% and MSH2 in 40%. Half of the mutations have not previously been reported and potential founder effects were identified in Brazil and in Colombia.ConclusionThe South American Lynch syndrome mutation spectrum includes multiple new mutations, identifies potential founder effects and is useful for future development of genetic testing in this continent.

Increased production of soluble TLR2 by lamina propria mononuclear cells from ulcerative colitis patients.

Toll-like receptor 2 (TLR2) is a type I pattern recognition receptor that has been shown to participate in intestinal homeostasis. Its increased expression in the lamina propria has been associated with the pathogenesis in inflammatory bowel disease (IBD), such as ulcerative colitis (UC) and Crohns disease (CD). Recently, soluble TLR2 (sTLR2) variants have been shown to counteract inflammatory responses driven by the cognate receptor. Despite the evident roles of TLR2 in intestinal immunity, no study has elucidated the production and cellular source of sTLR2 in IBD. Furthermore, an increase in the population of activated macrophages expressing TLR2 that infiltrates the intestine in IBD has been reported. We aimed first to assess the production of the sTLR2 by UC and CD organ culture biopsies and lamina propria mononuclear cells (LPMCs) as well as the levels of sTLR2 in serum, and then characterize the cell population from lamina propria producing the soluble protein. Mucosa explants, LPMCs and serum were obtained from UC, CD patients and control subjects. The level of sTLR2 was higher in conditioned media from organ culture biopsies and LPMCs from UC patients in comparison to CD and controls. Moreover, an inverse correlation between the content of intestinal and serum sTLR2 levels was observed in UC patients. Additionally, when characterizing the cellular source of the increased sTLR2 by LPMCs from UC patients, an increase in TLR2(+)/CD33(+) cell population was found. Also, these cells expressed CX3CR1, which was related to the increased levels of intestinal FKN in UC patients, suggesting that a higher proportion of TLR2(+) mononuclear cells infiltrate the lamina propria. The increased production of sTLR2 suggests that a differential regulating factor of the innate immune system is present in the intestinal mucosa of UC patients.

Prevalencia de la incontinencia fecal en centros de salud y casas de reposo

BACKGROUND Fecal and urinary incontinence (FI and UI) are psychologically and socially debilitating and embarrassing conditions. AIM To determine the prevalence of FI and associated factors in patients assessed in health centers (HC) and nursing home (NH) residents. MATERIAL AND METHODS Prospective, multicentric survey carried out in 3 HC and 16 NH of Santiago. Patients and residents of NH were interrogated about FI between March and July 2004. RESULTS The questionnaire was answered by 618 patients attending health centers aged 18 to 87 years (75% females) and 128 nursing home residents aged 40 to 103 years (80% females). The prevalence of liquid or solid FI in HC and NH was 2.7 and 45%, respectively. Among the latter, the incontinence for liquids and solids was 19% and 42%, respectively. The prevalence of UI was 30.1 and 62.7% in HC patients and NH residents, respectively. Among patients attending HC, multivariable analysis showed a relation between older age and urinary incontinence with liquid or solid FI. Among NH residents, multivariate analysis showed a relation between urinary incontinence and motor disabilities with liquid or solid FI. CONCLUSIONS The prevalence of liquid or solid FI among patients assessed in health center is 2.7%. This figure increases in older people, those with UI and in NH residents.

Cáncer colorrectal hereditario: análisis molecular de los genes APC y MLH1

Two FAP andone HNPCC families were studied. The APC gene (for FAP patients) and the MLH1 gene (forHNPCC patients), were screened for mutations on genomic DNA. The molecular analysis wasperformed through polymerase chain reaction, Single Strand Conformer Polymorphism (SSCP)and DNA sequencing. Mutations were defined as changes in the DNA sequence leading into a stopcodon and a truncated protein.

Indicaciones y resultados de la endosonografía ano-rectal: Análisis de las primeras 1000 endosonografías

Introduccion: La endosonografia anorrectal (EAR) es una alternativa diagnostica en las patologias anorrectales. Objetivo: Analizar las principales indicaciones y resultados de la EAR. Material y metodo: Estudio prospectivo, descriptivo desarrollado entre Noviembre 1999 hasta Septiembre 2004. Se correlaciono el informe de la EAR con los hallazgos quirurgicos y resultados de biopsias. Analisis mediante concordancia. Resultados: En el periodo mencionado se realizaron 1000 EAR, (62% mujeres, edad promedio 55 anos). Las indicaciones fueron etapificacion y seguimiento de cancer rectal (CR) en 279 pacientes, otros tumores 119, incontinencia fecal (IF) en 336, fistulas perianales en 137, dolor anal (DA) en 73, y otras indicaciones en 56 pacientes. En la etapificacion del CR la concordancia general para la profundidad tumoral y compromiso linfonodal fue 81,6% y 67,8%, respectivamente. En el estudio de IF, la EAR resulto normal en el 17%, se informo interrupcion de ambos esfinteres en 16% de los pacientes, interrupcion del esfinter anal externo en el 65% y del esfinter anal interno aislado en el 2%. En 30 pacientes operados por IF en nuestra institucion, hubo 100% de concordancia entre hallazgos endosonograficos e intraoperatorios. En el estudio por fistulas perianales, 10,2% normales, 64,2% confirmaron la fistula, 13,1% evidencio una coleccion y en el 12,5% otros diagnosticos. En el estudio por DA, 36 EAR fueron normales y en 37 se evidencio alguna alteracion (50,7%). Conclusion: Las indicaciones mas frecuentes fueron el estudio de pacientes con incontinencia fecal y etapificacion del cancer de recto. Existe adecuada concordancia entre hallazgos endosonograficos y quirurgicos

Estudio endoscópico en familiares de primer grado de pacientes operados por cáncer colorrectal

Background: First degree relatives of patients with colorectal carcinoma are at a higher risk of having the disease than the general population. Therefore, they should be subjected to screening colonoscopy. Aim: To assess the effectiveness of colonoscopy among first degree relatives of patients with colorectal carcinoma. Material and methods: A free colonoscopy was offered to first degree relatives of patients operated on for colorectal cancer between 1998 and 2000. As inclusion criteria, subjects had to be asymptomatic, older than 40 years or less than 10 years younger than the index case. Each subject was contacted twice, inviting him/her to have a colonoscopy performed. Results: Two hundred forty three relatives were contacted for the study and in 76, a colonoscopy was performed. Among the latter, a neoplasm was found in 13 (17%): One adenocarcinoma and 12 adenomas. Three of these lesions were located in the right colon. The main reason given by the 176 subjects that did not agree to have a colonoscopy was lack of interest. Conclusions: Screening colonoscopy is effective to detect adenoma and adenocarcinomaamong first degree relatives of patients with colorectal carcinoma, however only 31% of all potential relatives agreed to undergo a colonoscopy (Rev Med Chile 2006; 134: 997-1001). (Key words: Colonic neoplasms; Colonoscopy; Rectal neoplasms)

A survey of the clinicopathological and molecular characteristics of patients with suspected Lynch syndrome in Latin America

BackgroundGenetic counselling and testing for Lynch syndrome (LS) have recently been introduced in several Latin America countries. We aimed to characterize the clinical, molecular and mismatch repair (MMR) variants spectrum of patients with suspected LS in Latin America.MethodsEleven LS hereditary cancer registries and 34 published LS databases were used to identify unrelated families that fulfilled the Amsterdam II (AMSII) criteria and/or the Bethesda guidelines or suggestive of a dominant colorectal (CRC) inheritance syndrome.ResultsWe performed a thorough investigation of 15 countries and identified 6 countries where germline genetic testing for LS is available and 3 countries where tumor testing is used in the LS diagnosis. The spectrum of pathogenic MMR variants included MLH1 up to 54%, MSH2 up to 43%, MSH6 up to 10%, PMS2 up to 3% and EPCAM up to 0.8%. The Latin America MMR spectrum is broad with a total of 220 different variants which 80% were private and 20% were recurrent. Frequent regions included exons 11 of MLH1 (15%), exon 3 and 7 of MSH2 (17 and 15%, respectively), exon 4 of MSH6 (65%), exons 11 and 13 of PMS2 (31% and 23%, respectively). Sixteen international founder variants in MLH1, MSH2 and MSH6 were identified and 41 (19%) variants have not previously been reported, thus representing novel genetic variants in the MMR genes. The AMSII criteria was the most used clinical criteria to identify pathogenic MMR carriers although microsatellite instability, immunohistochemistry and family history are still the primary methods in several countries where no genetic testing for LS is available yet.ConclusionThe Latin America LS pathogenic MMR variants spectrum included new variants, frequently altered genetic regions and potential founder effects, emphasizing the relevance implementing Lynch syndrome genetic testing and counseling in all of Latin America countries.

Resultados y eventos adversos de la sigmoidectomía por cáncer: laparoscopia versus laparotomía

Resumen es: Objetivo: Comparar resultados y complicaciones inmediatas al realizar una sigmoidectomia laparoscopica (SL) versus abierta (SA) en pacientes con cancer d...

Cáncer de recto: diagnóstico, estudio y estadificación

Rectal cancer: diagnosis, study and staging Rectal cancer is defi ned as a tumour located between the anal verge and 15 cm within anal verge. In rectal cancer, a precise preoperative staging allows to categorize patients for different available treatments, as well as decide the best surgical treatment. Preoperative staging is performed by several radiological tech- niques. Currently available procedures are endorectal ultrasound (EUS), computed tomography (CT) mag- netic resonance (MRI), positron emission tomography-computed tomography (PET/CT) and intraoperative ultrasound. EUS is a procedure performed by the colorrectal surgeon that allows the evaluation of the depth of tumour invasion as well as lymph node status; nevertheless its main shortcoming is the inability to assess mesorectal fascia involvement. Nowadays, MRI is the best method to assess mesorectal fascia involvement in addition to tumour invasion and lymph nodes involved. CT is a widely available procedure, and its main use is evaluation of distant metastases, with lower accuracy to assess tumour invasion and lymph node status. PET/CT is currently gaining importance, however its role in preoperative staging its not widely accepted. IOUS allows evaluation of liver metastases during surgery, and therefore determines management and prog- nosis. Consequently, is necessary for surgeons to maintain an up-to-date knowledge of current methods, its advantages and limitations.