The endocrine response to nutrient ingestion is vital to the maintenance of energy homeostasis in the body. Glucagon like peptide-1 (GLP-1) is one such hormone that is released from L-cells of the distal small intestine and colon in response to meal ingestion. GLP-1 acts on various systems in the body to enhance glucose-stimulated insulin secretion, delay gastric emptying and promote satiety. As such, elevating the levels of active GLP-1 in the circulation, as well as enhancing GLP-1 bioactivity, is the basis of several recent anti-diabetic medications. Gaining an understanding of how GLP-1 secretion is regulated at the cellular level requires in vitro L-cell models. NCI-H716 is a cell line derived from ascites fluid of a colorectal adenocarcinoma from a 33 year old Caucasian male. This cell line is currently the only human model available for the in vitro study of GLP-1 regulation and is the topic of the following chapter. This chapter will cover the origin, characteristics and methods for using this model. Comparisons are then made between other available in vitro GLP-1 models.

The human colon adenocarcinoma cell line HT29, is not only used to study the biology of human colon cancers, but it is receiving special interest in studies focused on food digestion and bioavailability due to the ability to express characteristics of mature intestinal cells. In the differentiated phenotype, they are able to form a monolayer with tight junctions between cells and a typical apical brush border. In addition, these differentiated cells express brush-border-associated hydrolases typical of the small intestine although the enzymatic activity is lower than that found in vivo. Although they represent a valuable model due to their similarities with enterocytes of the small intestine, their limitations and the relevance to the in vivo situation are also considered in this chapter. The application of this cell line to transport studies of drugs and food compounds is illustrated, especially when the effect of the mucus layer is considered or used as co-culture in combination with Caco-2 cells. They have also been frequently used to study the intestinal immune response to bacterial infection, and microorganism survival, adhesion or invasion. Finally, the use of these cells to evaluate the effect of several food compounds and mucin secretion is summarized.

Probiotic microorganisms have attracted a growing interest for prevention and therapy of gastrointestinal disorders. Many probiotic strains have been shown to inhibit growth and metabolic activity of enteropathogenic bacteria as well as their adhesion and invasion to intestinal cells. In the present study, we evaluated the interference of bacteria-free supernatants (BFS) of cultures belonging to sixteen strains of lactobacilli and bifidobacteria, with invasion of enteroinvasive Escherichia coli (EIEC) strain, using human colonic adenocarcinoma cell lines, T84 and Caco2 cells. To assess invasion of Caco-2 and T84 cells by EIEC, and measure the number of pathogens inside the enterocytes, the gentamicin protection assay was conducted. In addition, three different invasion inhibition assays were designed; namelyco-incubation, pre-incubation and treatment with the BFS of probiotics. Data obtained and theoretical calculation showed that the most effective assay in the prevention of pathogen invasion was treatment withBFS.Besides, co-incubation assay was more valid than pre-incubation assay in invasion prevention.The obtained results suggest that probiotics may produce some metabolites that strongly prevent invasion of enteroinvasive E.coli into the small and large intestine. Also, probiotics are able to compete with or exclude pathogen invasion.

Primary adenocarcinoma of the small intestine comprises one of the rarest gastrointestinal malignancies. Further, the terminal ileum is very seldom implicated. This entity occurs sporadically and evades traditional colonoscopic evaluation in which the terminal ileum is not visualized. Herein, a case of interval development of primary terminal ileal adenocarcinoma over a 2-year period is reported as followed by direct endoscopic and colonoscopic visualization. This case demonstrates cecal involvement not found on initial evaluation without the provision of terminal ileum intubation. Relevant guidelines regarding the evaluation of the terminal ileum in routine colonoscopy are reviewed.

Appendiceal mucoceles (AMs) are rare mucin-containing neoplasms with malignant potential. Lack of evidence-based data exists defining clinicopathological features for management. MEDLINE search between 1995 and 2015 was performed using search criteria "Appendix mucocele." Systematic review of patient-, pathologic-, and treatment-related characteristics was performed and data analyzed. Among 276 cases of non-perforated AMs, 163 (59%) patients were female, with variable and nonspecific presentation. Patients were treated with appendectomy (52.1%), right hemicolectomy (17.6%), partial cecectomy (17.2%), and ileocecetomy (13.1%). Pathologic evaluation revealed the following: cystadenoma/low-grade appendiceal mucinous neoplasm (54%), unspecified/benign (25%), retention cyst (14.1%), cystadenocarcinoma (4.2%), and mucosal hyperplasia (2.9%). All 11 (4.2%) patients with cystadenocarcinoma were female (P = 0.004), odds ratio for malignancy 1.07 times higher for women. Synchronous colonic malignancy was reported in three patients (27%) with cystadenocarcinoma (P = 0.007), odds ratio of 12.1. AMs have low risk for malignancy. Treatment should begin with appendectomy-only and subsequently guided by pathologic diagnosis.