Presencia de Escherichia coli intracelular en mucosa intestinal de pacientes con Enfermedad Inflamatoria Intestinal y su asociación con características clínicas y el uso de corticosteroides / Presence of intracellular Escherichia coli in patients with inflammatory bowel disease

Background: Different strains of invasive Escherichia coli (E. coli), isolated from intestinal mucosa of patients, are related to the pathogenesis of inflammatory bowel diseases (IBD). Aim: To evaluate an association between intracellular E. coli and IBD; its clinical characteristics and use of steroids. Material and Methods: Sixty one patients with Crohn's disease and 83 with ulcerative colitis were studied. To determine the intracellular E. coli content, colonoscopy biopsies of these patients and 29 control subjects were processed using the gentamicin protection assay. Differences in the bacterial content between patient groups were evaluated using Mann-Whitney test, while the association between presence of E. coli with endoscopic activity, location/extension and use of corticosteroid as anti-inflammatory treatment were evaluated with Fisher's exact test or Chi-square test. Results: E. coli strains were detected in 36.1, 39.3 and 10.3% of patients with ulcerative colitis, Crohn's disease and controls, respectively. The number of bacteria per biopsy in Crohn's disease and ulcerative colitis was significantly higher than in controls (p < 0.01 between patients and controls). In ulcerative colitis, significant associations were found between the presence of bacteria and disease location and use of corticosteroids. In Crohn's disease, no association was found. Conclusions: IBD are associated with the presence of intracellular E. coli strains in the intestinal mucosa, suggesting an alteration in the microbiota or loss of integrity of the epithelial barrier. The association of intracellular E. coli with clinical features and the use of corticosteroids in ulcerative colitis suggests that different factors could promote colonization or proliferation of these bacteria.

Mutación homocigota en la línea germinal del gen MUTYH en una paciente chilena con poliposis adenomatosa familiar / Homozygous germline mutation in MUTYH gene in familial adenomatous polyposis

Recently, MUTYH mutations have been reported to predispose to the development of polyposis. However, polyposis caused by mutations in MUTYH has been characterized as an autosomal recessive hereditary disease, different from the autosomal dominant pattern observed in polyposis caused by APC mutations. We report a 41-year-old female consulting for anemia. Colonoscopy detected multiple sessile polyps and a cecal carcinoma. The patient was operated and in the surgical piece, the tumor invaded serosa and there was lymph node involvement. Approximately 100 polyps were found. The patient received 5-fluorouracil, as adjuvant therapy. The patient had a sister (of a total of 12 brothers) with a colorectal carcinoma. The genetic study identified a homozygous mutation of the MUTYH gene, called c.340T > C, that produces an amino acid change of tyrosine for histidine called p.Y114H. The sister with colorectal cancer was a heterozygous carrier of this mutation.

Síndrome de Lynch: Caracterización genético clínica. Caso clínico / Hereditary non-polyposis colorectal cancer: Report of four siblings

Hereditary non-polyposis colorectal cancer (HNPCC) or Lynch Syndrome is an autosomic dominant syndrome involving 596-1096 of colorectal cancer patients. Mutations in MLH1 and MSH2 genes account for most cases. These two genes particípate in the DNA mismatch repair pathway. Therefore mutation carriers show microsatellite instability (MSI) in tumors. This syndrome is characterized by the early development of colorectal cancer (before 50 years) and an increased incidence of cancer in other organs. We report four siblings from a family diagnosed with HNPCC. All of them were subjected to colonic surgery for colorectal cancer Moreover, one patient developed an ampulloma after her colon surgery. The molecular-genetic analysis revealed three brothers with microsatellite instability in the tumor tissue, the absence of the MLH1 protein, and the presence of a germ Une mutation localized in introm 15 ofthe MLH1 gene.