Evaluation of Escherichia coli STb toxin in an in vitro organ culture model (IVOC) / Avaliação de toxina STb de Escherichia coli em modelo de cultura de órgãos in vitro (IVOC)

ETEC pathogenesis comprises adhesion to the small intestine, colonization and enterotoxin production. STb is one of the heat-stable toxins produced by ETEC. Previous reports, using culture supernatants of STb-positive ETEC strains, indicated loss of villous absorptive cells causing mild atrophy and microscopic alterations in jejunum mucosa. These culture supernatants contained many other compounds beside STb toxin and in addition the quantity of toxin in these supernatants was not determined. Thus, this study was undertaken to evaluate the effect of pure STb toxin on piglet jejunum explants in an in vitro organ culture (IVOC) model. Tissues of piglets of 11 weeks were used and put into culture. Morphometric analysis of tissues revealed that villous epithelial area was reduced in tissues treated with pure STb after 3, 4 and 5 hours (p 0.0001) compared to untreated tissues. STb-treated tissues presented atrophic villi due to loss of villi tip. Our data shows that, in piglet jejunum explants, pure STb toxin can lead to cell modification and consequently to destruction, seen as villi atrophy. These changes result in a reduced absorptive area and could be partly responsible for the diarrhea observed in the animal following STb intoxication.

Aberrant Epithelial Differentiation Contributes to Pathogenesis in a Murine Model of Congenital Tufting Enteropathy

Background & AimsCongenital Tufting Enteropathy (CTE) is an intractable diarrheal disease of infancy caused by mutation of Epithelial Cell Adhesion Molecule (EpCAM). The cellular and molecular basis of CTE pathology has been elusive. We hypothesized that the loss of EpCAM in CTE results in altered lineage differentiation and defects in absorptive enterocytes thereby contributing to CTE pathogenesis.MethodsIntestine from CTE mice was evaluated for specific markers by RT-qPCR, western blotting and immunostaining. Body weight, blood glucose and intestinal enzyme activity were also investigated. A CTE enteroid model was used to assess whether the decreased census of secretory cells could be rescued.ResultsCTE mice exhibited alterations in brush-border function, disaccharidase activity and glucose absorption, potentially contributing to nutrient malabsorption and impaired weight gain. Altered cell differentiation in CTE mice led to decreased secretory cells and increased numbers of absorptive cells, though the absorptive enterocytes lacked key features, causing brush border malfunction. Further, treatment with Notch signaling inhibitor, DAPT, increased the numbers of major secretory cell types in CTE enteroids (Graphical abstract 1).ConclusionsAlterations in intestinal epithelial cell differentiation in CTE mice favor an increase in absorptive cells at the expense of secretory cells. Although the proportion of absorptive enterocytes is increased, they lack key functional properties. We conclude that these effects underlie pathogenic features of CTE such as malabsorption and diarrhea, and ultimately the failure to thrive seen in patients. The ability of DAPT to reverse aberrant differentiation suggests a possible therapeutic strategy.SynopsisA murine model of Congenital Tufting Enteropathy exhibits altered intestinal cell differentiation, leading to increased absorptive and decreased secretory cells, which can be reversed with DAPT. Absorptive enterocytes in these mice are also dysfunctional, contributing to disease pathogenesis.Graphical Abstract

Light microscopic study on the absorptive cells and goblet cells in the intestine of adult common carp Cyprinus carpio

The purpose of this study was to describe of some histological structures and histochemical features of the absorptive cells and goblet cells in intestine of common carp. In this study, Fifteen adult male common carp were catching alive from the AL-Forat river, with age about (7 - 12) months and mean of their weight was (2100 ± 81 g) and mean standard length was (50.4 ± 3.1 cm), immediately after death.Incision was made through the midventral line of the fish just from cranial to the anus to expose the intestine, specimens of intestine were taken and washed with (0.9 %) normal saline solution. Ten samples were obtained from different regions of each portion of the intestine (anterior, middle and posterior), fixed by either 10% neutral buffered formalin or Bouin’s solution approximately 24 hours at room temperature and then treated by routine histological processing. The stains were used, Hematoxylin and Eosin, periodic acid Schiff, Alcian blue pH 2.5, and Combinated Alcian blue PH 2.5 plus periodic acid Schiff. The Mean number, height and width of mucosal folds were measured and counts of goblet cells in the mucosal folds of each portion of the intestine. The results showed that the intestinal epithelium is simple columnar, the enterocytes were tall columnar cells with brush border; goblet cells were ovoid, located between the enterocytes. The folds composed of the entire thickness of the mucosa, mean number, height and width of the mucosal folds were few in posterior portion of intestine compare with that in other portions. The anterior portion of the intestine has largest number of mucosal folds, while has less number of goblet cells compare to middle and posterior portions of the intestine. The epithelial cells stained red-purple by periodic acid Schiff stain with Alcian blue, the goblet cells were take positive reaction with periodic acid Schiff stain, and with Alcian blue plus periodic acid Schiff, while negative with only Alcian blue stain. Glycoprotein staining intensity varied from very weak to moderate, whereby the presence of neutral, acidic and sulphatedglycoconjugates. In conclusion, numbers of goblet cells were observed to be increased towards posterior portion of intestine required as lubricant for fecal expulsion, and reversed relation between number of the folds and goblet cells.

The Effect of Aerobic and Anaerobic Physical Training on the Absorptive Cells, Absorption of Carbohydrate and Protein in Small Intestine

The purpose of this study is to investigate the morphofunctional response of a total number of absorptive cells, and carbohydrate and protein absorption capability in the small intestine of Rattus norvegicus strain Wistar (RNSW) that has been subjected to aerobic and anaerobic physical training based on the morphofunctional physiological paradigm. This study was based on the separate sample pretest-posttest control group design, using a t-test, and multivariate SPSS ten program, with five percent level of significance. The sample consisted of one hundred and twenty, male RNSW, with average age of five months, and body weight of 246-278 grams. They were divided into twelve groups at random, i.e. four pretest groups, two control groups, and six treated groups where different diets were given thirty minutes before undergoing posttest. The experimental animals underwent four weeks physical training (twelve times), three groups were given aerobic physical training by swimming with a burden of three percent fasting body weight, the others three groups received anaerobic physical training by swimming with a burden of nine percent fasting body weight. The experiment was conducted at night, between 7.30 PM to 10.30 PM, in a water with a temperature of 28°C to 30°C. Result of the study revealed: (1) Aerobic and anaerobic physical training, increased the number of absorptive cells (t = -73,281, p = 0,000), and increased the absorptive capacity of carbohydrate and protein (Hotelling’s Trace = 0,244, p = 0,000). (2) There was a difference in the increased absorptive capacity of carbohydrate and protein among groups (Hotelling’s Trace = 0,404a, p = 0,000). Aerobic physical training had less influence than anaerobic physical training on the increased number of absorptive cells, and the absorptive capacity of carbohydrate and protein in the small intestine. In conclusion: (1) Aerobic physical training of swimming with a burden of three percent fasting body weight, and anaerobic physical training of swimming with a burden nine percent fasting body weight correlate with the increase the number of absorptive cells, and carbohydrate and protein absorptive capacity of the small intestine. (2) Anaerobic physical training of swimming with a burden nine percent fasting body weight has better correlation than aerobic physical training of swimming with a burden of three percent fasting body weight with the increased number of absorptive cells, and the absorptive capacity of carbohydrate and protein in the small intestine.

The Histology ofNanomia bijuga(Hydrozoa: Siphonophora)

The siphonophoreNanomia bijugais a pelagic hydrozoan (Cnidaria) with complex morphological organization. Each siphonophore is made up of many asexually produced, genetically identical zooids that are functionally specialized and morphologically distinct. These zooids predominantly arise by budding in two growth zones, and are arranged in precise patterns. This study describes the cellular anatomy of several zooid types as well as of the stem and gas-filled float, called the pneumatophore. The distribution of cellular morphologies across zooid types enhances our understanding of zooid function. The unique absorptive cells in the palpon, for example, indicate specialized intracellular digestive processing in this zooid type. Though cnidarians are usually thought of as mono-epithelial, we characterize at least two cellular populations in this species which are not connected to a basement membrane. This work provides a greater understanding of epithelial diversity within the cnidarians, and will be a foundation for future studies onNanomia bijuga, including functional assays and gene expression analyses.