Cytoplasm Of Enterocytes Research Articles

Effects of Cadmium Exposure on Gut Villi in Danio rerio.

In aquatic organisms, cadmium exposure occurs from ovum to death and the route of absorption is particularly wide, being represented by skin, gills and gastrointestinal tract, through which contaminated water and/or preys are ingested. It is known that cadmium interferes with the gut; however, less information is available on cadmium effects on an important component of the gut, namely goblet cells, specialized in mucus synthesis. In the present work, we studied the effects of two sublethal cadmium concentrations on the gut mucosa of Danio rerio. Particular attention was paid to changes in the distribution of glycan residues, and in metallothionein expression in intestinal cells. The results show that cadmium interferes with gut mucosa and goblet cells features. The effects are dose- and site-dependent, the anterior gut being more markedly affected than the midgut. Cadmium modifies the presence and/or distribution of glycans in the brush border and cytoplasm of enterocytes and in the goblet cells’ cytoplasm and alters the metallothionein expression and localization. The results suggest a significant interference of cadmium with mucosal efficiency, representing a health risk for the organism in direct contact with contamination and indirectly for the trophic chain.

CAMP: A second messenger involved in the mechanism of midgut alkalinization in Lutzomyia longipalpis.

The sand fly Lutzomyia longipalpis is the main vector of Leishmania infantum in the Americas. Female sand flies ingest sugar-rich solutions and blood, which are digested in the midgut. Digestion of nutrients is an essential function performed by digestive enzymes, which require appropriate physiological conditions. One of the main aspects that influence enzymatic activity is the gut pH, which must be tightly controlled. Considering second messengers are frequently involved in the coordination of tightly regulated physiological events, we investigated if the second messenger cAMP would participate in the process of alkalinization in the abdominal midgut of female L. longipalpis. In midguts containing the indicator dye bromothymol-blue, cAMP stimulated the alkalinization of the midgut lumen. Through another technique based on the use of fluorescein as a pH indicator, we propose that cAMP is involved in the alkalinization of the midgut by activating HCO3- transport from the enterocyte's cytoplasm to the lumen.The results strongly suggested that the carrier responsible for this process would be a HCO3- /Cl- antiporter located in the enterocytes' apical membrane. Hematophagy promotes the release of alkalinizing hormones in the hemolymph; however, when the enzyme adenylyl cyclase, responsible for cAMP production, was inhibited, we observed that the hemolymph from blood-fed L. longipalpis' females did not stimulate midgut alkalinization. This result indicated that hormone-stimulated alkalinization is mediated by cAMP. In the present study, we provide evidences that cAMP has a key role in the control of intestinal pH.

Postoperative Onset and Detection of SARS-CoV-2 in Surgically Resected Specimens From Gastrointestinal Cancer Patients With Pre/Asymptomatic COVID-19.

Objective:To describe the epidemiologic features and clinical courses of gastrointestinal cancer patients with pre/asymptomatic COVID-19 and to explore evidence of SARS-CoV-2 in the surgically resected specimens.Summary Background Data:The advisory of postponing or canceling elective surgeries escalated a worldwide debate regarding the safety and feasibility of performing elective surgical procedures during this pandemic. Limited data are available on gastrointestinal cancer patients with pre/asymptomatic COVID-19 undergoing surgery.Methods:Clinical data were retrospectively collected and analyzed. Surgically resected specimens of the cases with confirmed COVID-19 were obtained to detect the expression of ACE2 and the presence of SARS-CoV-2.Results:A total of 52 patients (male, 34) with a median age 62.5 years were enrolled. All the patients presented no respiratory symptoms or abnormalities on chest computed tomography before surgery. Six patients (11.5%) experienced symptom onset and were confirmed to be COVID-19. All were identified to be preoperatively pre/asymptomatic, as 5 were with SARS-CoV-2 presenting in cytoplasm of enterocytes or macrophages from the colorectal tissues and 1 had symptom onset immediately after surgery. The case fatality rate in patients with COVID-19 was 16.7%, much higher than those without COVID-19 (2.2%).Conclusions:Gastrointestinal cancer patients with pre/asymptomatic COVID-19 were at high risk of postoperative onset and death. At current pandemic, elective surgery should be postponed or canceled. It highlights the need for investigating the full clinical spectrum and natural history of this infection. The early colorectal tropism of SARS-CoV-2 may have major implications on prevention, diagnosis, and treatment of COVID-19.

The Snakeskin-Mesh Complex of Smooth Septate Junction Restricts Yorkie to Regulate Intestinal Homeostasis in Drosophila.

SummaryTight junctions in mammals and septate junctions in insects are essential for epithelial integrity. We show here that, in the Drosophila intestine, smooth septate junction proteins provide barrier and signaling functions. During an RNAi screen for genes that regulate adult midgut tissue growth, we found that loss of two smooth septate junction components, Snakeskin and Mesh, caused a hyperproliferation phenotype. By examining epitope-tagged endogenous Snakeskin and Mesh, we demonstrate that the two proteins are present in the cytoplasm of differentiating enteroblasts and in cytoplasm and septate junctions of mature enterocytes. In both enteroblasts and enterocytes, loss of Snakeskin and Mesh causes Yorkie-dependent expression of the JAK-STAT pathway ligand Upd3, which in turn promotes proliferation of intestinal stem cells. Snakeskin and Mesh form a complex with each other, with other septate junction proteins and with Yorkie. Therefore, the Snakeskin-Mesh complex has both barrier and signaling function to maintain stem cell-mediated tissue homeostasis.

The role of LuloPAT amino acid/proton symporters in midgut alkalinization in the sandfly Lutzomyia longipalpis (Diptera – Psychodidae)

In Lutzomyia longipalpis females, which are the main vectors of Leishmania infantum in the Americas, hematophagy is crucial for ovary development. The control of pH in the midgut during blood digestion is important to the functioning of the digestive enzymes, which release amino acids in the luminal compartment that are then transported through the enterocytes to the hemolymph for delivery to the ovary and other organs. In the present work, we investigated transport systems known as LuloPATs that are present in the midgut of L. longipalpis but not in other organs. These transporters achieve symport of amino acids with H+ ions, and one of them (LuloPAT1) is orthologous to a transporter described in Aedes aegypti. According to our results, the transcription levels of LuloPAT1 increased significantly immediately after a blood meal. Based on the variation of the fluorescence of fluorescein with the pH of the medium, we developed a technique that shows the acidification of the cytoplasm of gut cells when amino acids are cotransported with H+ from the lumen into the enterocytes. In our experiments, the midguts of the sandflies were dissected and opened longitudinally so that added amino acids could enter the enterocytes via the lumen (PAT carriers are apical). LuloPAT1 transporters are part of a complex of mechanisms that act synergistically to promote gut alkalinization as soon as blood intake by the vector occurs. In dissected but not longitudinally opened midguts, added amino acids could only enter through the basolateral region of enterocytes. However, alkalinization of the lumen was observed because the entry of some amino acids into the cytoplasm of enterocytes triggers a luminal alkalinization mechanism independent of LuloPATs. These findings provide new perspectives that will enable the characterization of the set of signaling pathways involved in pH regulation within the L. longipalpis midgut.

P4.37: Extra-Intestinal Manifestations of Children with Genetically Confirmed Microvillus Inclusion Disease

Objectives: Microvillous inclusion disease (MVID): congenital disorder caused by MYO5B or STX3 mutations. Pathognomonic features are severe intractable diarrhoea and malabsorption due to intestinal brush border atrophy, accumulation of lysosomal granules and microvillus inclusions in the apical cytoplasm of enterocytes. All epithelial tissues express MYO5B but gut involvement is classically described. Method: Two males: A, 2-year-old Pakistani and B, 12-month-old Kuwaiti with MYO5B mutation. Results: Patient A: Neonatal secretory diarrhea with high fluid and electrolyte requirements, deteriorated on feed introduction. Duodenal histology: blunted villi, hyperplastic crypts, loss of surface epithelium, goblet cell depletion and apoptosis. Periodic acid–Schiff (PAS) and CD10 staining suggested MVID, confirmed by electron microscopy (EM). Genetics: homozygosity of MYO5B gene: c.1087C>T mutation. He was discharged on home parenteral nutrition (PN) at 10 months with ongoing high volume and sodium demands, gradually worsening diarrhea and minor transaminitis in his first year but otherwise stable liver function. Annual PN screening showed low TMP/GFR (0.89mmol/L), elevated cystatin C (1.27mg/L), biochemical evidence of renal tubular leak and radiological signs of rickets but no nephrocalcinosis. Fanconi syndrome was diagnosed. Currently on 24hr PN (250ml/kg) with large amounts of electrolytes, phosphate, acetate with over 20 watery stools/day. He was referred for small bowel (SB) transplantation. Patient B: Neonatal watery diarrhea and severe acidosis with feed introduction. He was commenced on PN, tertiary referral to London at 2months; arriving in poor nutritional status, marked conjugated hyperbilirubinemia and transaminitis. SB mucosal biopsies demonstrated total villous atrophy, focally vacuolated superficial epithelium and few intraepithelial lymphocytes. PAS and CD10 staining suggested MVID confirmed by EM. Genetics: compound heterozygosity for MYO5B gene mutations; c.1576C>T; p. and c.2111del; p. variant. Liver biopsy: lobular cholestasis, hepatocyte giant cell transformation and bridging fibrosis. He currently tolerates small amount of an amino-acid based formula and 170ml/kg/day PN with 10-hours break; with stable diarrhea (6–7/day). Due to severe liver injury and long term PN, he is being assessed for combined liver and SB transplantation. Conclusion: MVID has variable phenotypes, with other organ involvement such as liver and kidney apart from the gut.

Expression of GCRG213p, LINE-1 endonuclease variant, significantly different in gastric complete and incomplete intestinal metaplasia

BackgroundIntestinal metaplasia (IM) of the gastric mucosa is classified as complete (Type I) and incomplete IM (Type II and III) subtypes, which showed significantly different risk for developing to gastric adenocarcinoma (GAC). GCRG213, a variant of L1-endonuclease (L1-EN), first identified in our lab, was upregulated in GAC tissue. However, the relationship between GCRG213 and IM subtypes is not clear. Our study explored the association of GCRG213 protein (GCRG213p) with IM subtypes.MethodsGastric cancer and/or para-tumor tissue samples were collected from 123 patients who underwent gastrectomy for intestinal type gastric adenocarcinoma. The subtypes of IM were characterized with Alcian blue-periodic acid-Schiff and High Iron Diamine-Alcian blue staining methods. Immunohistochemistry of GCRG213p was performed, and its expression in gastric adenocarcinoma and para-tumor tissue including dysplasia, IM, and normal mucosa were analyzed.ResultsGCRG213p was expressed in 48.94% IM, 57.14% dysplasia and 55.32% GAC, respectively. GCRG213p expression was higher in well and moderately differentiated adenocarcinoma (P = 0.037). In IM glands, GCRG213p expressed mainly in the cytoplasm of absorptive enterocytes with defined brush borders, but not in goblet cells. The expression of GCRG213p in type I IM (90.00%) was significantly higher than that in type II (36.36%) and type III (25.00%) (P < 0.001). In normal gastric mucosa, GCRG213p was exclusively positive in the cytoplasm of gastric chief cells.ConclusionsThe expression of GCRG213p in complete IM was significantly higher than in incomplete IM, which implies that GCRG213p may play a role on the developing of IM to adenocarcinoma. GCRG213p was exclusively expressed in chief cells, suggesting that it might be involved in cell differentiation from the chief cells to IM.

Histochemical distribution of four types of enzymes and mucous cells in the intestine of koi carp (Cyprinus carpio var. koi).

The main purpose of this study was to investigate the distribution of acid phosphatase (ACP), alkaline phosphatase (ALP), non-specific esterase (NSE), peroxidase (POD), and mucous cells in the intestine of the koi carp Cyprinus carpio var. koi. ACP activity was located in the striated border, enterocytes, and lamina propria of the anterior and middle intestines. The ACP activity in the anterior intestine was higher than that in the middle and posterior intestines. ALP existed in the striated border of enterocytes and lamina propria, serosa, muscular layer, and the junction between muscular layer and submucosa layer of the intestine. The ALP activity in the anterior intestine was higher than that in the middle and posterior intestines. NSE activity was localized in the cytoplasm of enterocytes in the whole intestine, and the middle intestine showed the lower NSE activity than the anterior and posterior intestines. POD activity was localized in the blood cells of the lamina propria and cytoplasm of enterocytes in all intestinal segments. The POD activity among the anterior, middle, and posterior intestines was non-significantly different. Alcian blue periodic acid-Schiff histochemical results revealed three types of mucous cells in the intestine. The total number of mucous cells and percentage of type I cells among the anterior, middle, and posterior intestines were non-significantly different. The percentage of the type II cells was the highest in the posterior intestine, while the lowest in the anterior intestine. The percentage of the type III cells was the highest in the anterior intestine, while the lowest in the posterior intestine.

Morphological characterization of the adherence and invasion of Streptococcus agalactiae to the intestinal mucosa of tilapia Oreochromis sp.: An in vitro model.

Streptococcosis in tilapia Oreochromis sp. is possibly the most important bacterial disease for fish production worldwide. In Colombia, streptococcosis is caused by Streptococcus agalactiae (GBS), but in other countries, Streptococcus iniae is also involved. Prevention of streptococcosis is required and must be addressed for economic, social, international trade and public health reasons. This research used an in vitro culture of tilapia intestine to detail the intestinal mucosal response once the pathogen contacts the epithelium. We show that S.agalactiae sheds off its capsule to adhere to the epithelium. The bacterium adheres as a single individuum, in groups or in chains and is able to divide on the apical border of enterocytes. GBS adheres at and invades exclusively through the apical portion of the intestinal folds, using the transepithelial route. Once within the cytoplasm of enterocytes, the bacteria continue to divide. On the basolateral side of the epithelium, the microorganisms leave the cells to reach the propria and travel through the microcirculation. No evidence of an immuno-inflammatory reaction or goblet cell response in the epithelium or the lamina propria was seen during the process of adherence and invasion of the pathogen.

Rare Case of Chronic Diarrhoea in an Immunocompetent Host

Chronic diarrhoea is one of the common presenting symptoms of patients attending gastroenterology clinics. Cyclosporacayetanensis is a protozoan parasite causing intestinal infections. Most of these infections are self-limiting in immunocompetent individuals. However prolonged course of infection is often observed in immunocompromised individuals and rarely in normal individuals. In our case report, 50-year-old patient from west Bengal, India presented with chronic small bowel type of diarrhoea with significant weight loss. Serology for HIV was negative. Endoscopic biopsy from duodenum showed villous atrophy and crypt hyperplasia mimicking sprue with presence of oval round structures within parasitophorous vacuoles located in the supra nuclear cytoplasm of enterocytes, consistent with cyclospora infestation. Same biopsy also showed CMV inclusion bodies in the background. He was managed with oral Trimethoprim/sulfamethoxazole for cyclospora and valganciclovir for CMV. Conclusion: Mixed infection of cyclospora and cytomegalovirus presenting as chronic diarrhoea was rarely reported in an immunocompetent individual. Duodenal biopsy may help in differentiating parasitic infections from tropical sprue by demonstrating various forms of pathogens in histology.

The dynamics of a Chinese porcine G9P[23] rotavirus production in MA-104 cells and intestines of 3-day-old piglets.

Rotavirus A (RVA) G9 genotype is recognized as an emerging genotype which is spreading worldwide, however, our knowledge on pathogenicity of this virus is limited. In this study, porcine RVA strain HN03 was successfully isolated on MA-104 cells, and the isolate was propagated continuously for 7 passages after a virus cloning at passage 3. The virus titers from 4 to 10 passages ranged from 107.1 to 108.1 TCID50/ml. The growth curve of HN03 strain in cell culture was determined, and the virus production dynamics was confirmed by immunoperoxidase monolayer assay (IPMA). Sequence and phylogenetic analyses based on full-length VP7 and partial VP4 genes indicated that HN03 strain belongs to genotype G9P[23]. In addition, the sixth passage of strain HN03 in cell culture was subjected to 3-day-old piglets. All infected piglets developed severe watery diarrhea within 24 hr post-inoculation (hpi), but recovered from disease after 72 hpi. RVA antigen could be detected by IHC in the cytoplasm of villous enterocytes as early as 2 hr after appearance of clinical symptoms and virus antigen load kept increasing in the next 30 hr. The dynamics of RVA HN03 strain proliferation on cells and in pigs extended our understanding of rotavirus pathogenicity.

EFFECT OF PROBIOTIC BACTERIA AND LIPOPOLISACCHARIDES ON EPITELIOCYTES TIGHT JUNCTIONS OF RAT JEJUNUM

Aim. The present study has been undertaken with the main objective the influence of probiotic bacteria Lactobacillus plantarum 8 РАЗ and Escherichia coli M17 and lipopolysaccharide on the ultrastructure of enterocytes tight junctions of mucous membranes of rat jejunum. Materials and methods. The study was carried out on E. coli lipopolysaccharide (Sigma-Aldrich, Germany) and probiotic bacteria L. plantarum 8PA3 and E. coli M17. Male Wistar rats were used. A comparative analysis of the ultrathin structure of enterocytes and tight junctions were carried out by successive incubation of rat jejunum with probiotic bacteria L. plantarum 8PA3 and E. coli Ml 7, with lipopolysaccharide and a complex of bacteria with LPS. Results. The effect of L. plantarum 8PA3 on the mucosa of rats jejunum on a number of characters was similar to E. coli Mil. It manifested by preservation of the intact structure of the intercellular space and tight junctions. At the same time, hollow spherical inclusions with fragments of bacteria surrounded by membranes detected in the cytoplasm of enterocytes testified to the possibility of penetration of probiotic bacteria through the mucous membrane of the jejunum by a transcellular pathway With simultaneous action on enterocytes of rats jejunum of probiotic bacteria and lipopolysaccharide complex no destructive changes in the structure of dense contacts were observed, however, in a significant number of cases, bacterial cells were found in the intercellular space next to the goblet cells. Conclusion. A similar effect of Gram-positive bacteria L. plantarum 8PA3 and Gram-negative bacteria E. coli Ml 7 and their complexes with lipopolysaccharide on the jejunum epitheliocytes was revealed. Morphological analysis showed that lipopolysaccharide might influence on parasel-lular transport by probiotic bacteria. In the absence of LPS, probiotic bacteria can possibly penetrate the mucosa of rats jejunum by a transcellular pathway.

Hydrodynamic IL10 Gene Transfer in Human Colon: Results from an "EX VIVO" Study with Potential Clinical Application in Crohn's Disease.

The aim of this work is to evaluate the efficacy of hydrodynamic venous IL10 gene delivery to "ex vivo" human colon segments and to determine its potential interest in Crohn's disease treatment. Twenty human colon segments were obtained from surgical resections. Hydrodynamic transfection through the main vein of the pedicle with 50 mL of hIL10 plasmid (20 μg/mL) solution was performed on 13 of them. Tissue sections were cultured and DNA, RNA, and protein copies were determined after 1, 2, and 4 days. Data obtained were compared with 6 nontransfected specimens. Finally, 1 specimen was injected with gold nanoparticles, and their distribution was examined under electron microscope. IL10 DNA levels were higher in treated tissues than in controls (P < 0.001), decreasing along time. The amount of hIL10 RNA was significantly increased in treated tissues when compared with controls (P = 0.001). The indexes of protein IL10 translation in treated groups were much higher (P < 0.001) than the basal production. The protein expression was higher in transfected tissue (10-50-fold, with respect to control tissue); this difference being established during the first hours and maintained during, at least, 4 days. With electron microscopy, we hardly observed large (15 nm) gold nanoparticles within the tissue, always in the submucosa. However, multiple small (4 nm) nanoparticles were observed within the cytoplasm of enterocytes in mucosa. Hydrodynamic procedure efficiently delivers the IL10 gene to the human colon, achieving levels of tissue protein expression high enough to mediate pharmacological effects with interest in controlling immune response in patients with Crohn's disease.

Abnormal Rab11‐Rab8‐vesicles cluster in enterocytes of patients with microvillus inclusion disease

Microvillus inclusion disease (MVID) is a congenital enteropathy characterized by accumulation of vesiculo-tubular endomembranes in the subapical cytoplasm of enterocytes, historically termed "secretory granules." However, neither their identity nor pathophysiological significance is well defined. Using immunoelectron microscopy and tomography, we studied biopsies from MVID patients (3× Myosin 5b mutations and 1× Syntaxin3 mutation) and compared them to controls and genome-edited CaCo2 cell models, harboring relevant mutations. Duodenal biopsies from 2 patients with novel Myosin 5b mutations and typical clinical symptoms showed unusual ultrastructural phenotypes: aberrant subapical vesicles and tubules were prominent in the enterocytes, though other histological hallmarks of MVID were almost absent (ectopic intra-/intercellular microvilli, brush border atrophy). We identified these enigmatic vesiculo-tubular organelles as Rab11-Rab8-positive recycling compartments of altered size, shape and location harboring the apical SNARE Syntaxin3, apical transporters sodium-hydrogen exchanger 3 (NHE3) and cystic fibrosis transmembrane conductance regulator. Our data strongly indicate that in MVID disrupted trafficking between cargo vesicles and the apical plasma membrane is the primary cause of a defect of epithelial polarity and subsequent facultative loss of brush border integrity, leading to malabsorption. Furthermore, they support the notion that mislocalization of transporters, such as NHE3 substantially contributes to the reported sodium loss diarrhea.

Immunohistochemical characterization of Toll-like receptor 2 in gut epithelial cells and macrophages of goldfish Carassius auratus fed with a high-cholesterol diet

Toll-like receptors (TLRs) are a group of pattern recognition molecules that play a crucial role in innate immunity. The structural conservation of the archaic TLR system suggests that the regulation of the immune response might be similar in fish and mammals. Several TLRs (TLR-1, -2, and -4) are expressed by activated macrophages, “foam cells” in human atherosclerotic lesions. To date, 20 different TLRs were identified in more than a dozen different fish species. In this study we found that feeding goldfish, Carrassius auratus, a high-cholesterol diet (HCD) resulted macrophage foam cell formation in the intestinal tissues. The expression of TLR2 has been found in foam cells and in the cytoplasm of enterocytes, however the staining was more intense at the apical surface of polarized intestinal epithelial cells and in the lamina propria. In the intestinal epithelial cells and in the lamina propria cells of the control fish the TLR2 was expressed at low levels. The intestinal epithelium is directly involved in the mucosal immune response through its expression of proinflammatory genes, release of inflammatory cytokines, and recruitment of inflammatory cells.

Multilabel immunofluorescence and antigen reprobing on formalin-fixed paraffin-embedded sections: novel applications for precision pathology diagnosis

We report new methods for multilabel immunofluorescence (MIF) and reprobing of antigen epitopes on the same formalin-fixed paraffin-embedded (FFPE) sections. The MIF method includes an antigen-retrieval step followed by multilabel immunostaining and examination by confocal microscopy. As examples, we illustrate epitopes localized to the apical and basolateral membranes, and the cytoplasm of enterocytes of normal small intestine and in cases of congenital enteropathies (microvillous inclusion disease and congenital tufting enteropathy). We also demonstrate localization of the bile salt excretion pump protein (BSEP) in bile canalicular membrane of normal hepatocytes and in cases of primary sclerosing cholangitis. To demonstrate colocalization of cytoplasmic and nuclear epitopes we analyzed normal control and hyperplastic pulmonary neuroendocrine cells (PNEC) and neuroepithelial bodies (NEBs), presumed airway sensors in the lungs of infants with bronchopulmonary dysplasia (BPD). As cytoplasmic markers we used anti-bombesin or anti-synaptic vesicle protein 2 (SV2) antibody, respectively, and for nuclear localization, antibodies against neurogenic genes mammalian achaete-scute homolog (Mash1) and prospero homeobox 1 (Prox1), essential for NEB cells differentiation and maturation, hypoxia-inducible factor 1α (HIF1α) a downstream modulator of hypoxia response and a proliferation marker Ki67. The reprobing method consisted of removal of the previously immunolabeled target and immunostaining with different antibodies, facilitating colocalization of enterocyte brush border epitopes as well as HIF1α, Mash1 and Prox1 in PNEC/NEB PNEC and NEBs. As these methods are suitable for routine FFPE pathology samples from various tissues, allowing visualization of multiple epitopes in the same cells/sections with superior contrast and resolution, they are suitable for a wide range of applications in diagnostic pathology and may be particularly well suited for precision medicine diagnostics.

Does Salt Obesity Exist?

Background: Glucose transport within the intestine is performed by the SGLT1 cotransporter if it is attached to two sodium ions. Salt provides one sodium ion per molecule consumed. In humans its ingestion is commonly ten times the amount needed and its consumption is generally accompanied by high carbohydrate diets. This project evaluates if a large salt intake in the diet leads to the development of obesity. This work was raised thinking that a simple strategy to reduce the weight would decrease the amount of salt in food. Methods: The effect of salt on the dynamics of glucose absorption in the gut was evaluated making glucose tolerance curves with salt (1.55 molar of glucose 3.1 molar of salt) and without salt. Salty tastes simulating increased food intake and promoting weight gain in Wistar rats were also analysed. Results: The experiments showed that excessive salt intake prevents the transport of glucose from the intestinal lumen into the bloodstream. Additionally, salty tastes favoured increased food intake and weight gain. Conclusion: Sodium that naturally flows from the cytoplasm of enterocytes into the intestinal lumen, maintains the glucose cotransporter SGLT1 saturated and ensures at all times the transport of glucose that has been ingested in the diet. Excessive salt intake prevents the absorption of glucose from the intestinal lumen. Moreover, salty taste favours increased food intake and weight gain in Wistar rats.

Bacterial uracil modulates Drosophila DUOX-dependent gut immunity via Hedgehog-induced signaling endosomes.

Genetic studies in Drosophila have demonstrated that generation of microbicidal reactive oxygen species (ROS) through the NADPH dual oxidase (DUOX) is a first line of defense in the gut epithelia. Bacterial uracil acts as DUOX-activating ligand through poorly understood mechanisms. Here, we show that the Hedgehog (Hh) signaling pathway modulates uracil-induced DUOX activation. Uracil-induced Hh signaling is required for intestinal expression of the calcium-dependent cell adhesion molecule Cadherin 99C (Cad99C) and subsequent Cad99C-dependent formation of endosomes. These endosomes play essential roles in uracil-induced ROS production by acting as signaling platforms for PLCβ/PKC/Ca2+-dependent DUOX activation. Animals with impaired Hh signaling exhibit abolished Cad99C-dependent endosome formation and reduced DUOX activity, resulting in high mortality during enteric infection. Importantly, endosome formation, DUOX activation, and normal host survival are restored by genetic reintroduction of Cad99C into enterocytes, demonstrating the important role for Hh signaling in host resistance to enteric infection.

Feeding common sole (Solea solea) juveniles with increasing dietary lipid levels affects growth, feed utilization and gut health

Knowledge about the nutritional requirements of common sole (Solea solea) is limited and no information regarding the optimal dietary lipid level is available yet. Thus, this study was undertaken to assess the growth response and feed utilization of common sole juveniles fed diets with increasing lipid levels. Four isonitrogenous (59% protein) pelletized diets with different dietary lipid levels (8%, 12%, 16% and 20%; L8, L12, L16 and L20, respectively) were fed to triplicate fish groups of 80 individuals to apparent satiation over 150days. A one-way ANOVA, Tukey's post hoc test and linear regression were used to analyse the data (P≤0.05). At the end of the trial, final body weight was significantly higher in fish fed L8 (40.7±1.7g), followed by those fed L12 (35.1±1.2g), L16 (27.9±2.5g) and L20 (22.1±0.3g). The specific growth rate was higher in fish fed L8 and L12, compared to the other treatments, and it was lowest in L20. Voluntary feed intake decreased with an increase in the dietary lipid level. The feed conversion rate, the protein efficiency ratio and the gross protein efficiency were lower in fish fed L20, while no significant differences were observed among L8, L12 and L16. Gross lipid efficiency was significantly higher in fish fed low lipid diets. Histological observations showed that 19 of 36 observed subjects had lipid droplets in the cytoplasm of enterocytes at the apex of the mucosal folds and, in some cases, also along the entire fold (intestinal steatosis). The number of fish with intestinal steatosis in groups L20 and L16 was significantly higher than the number in group L8. Ultrastructure showed large electrondense lipid droplets within the cytoplasm of enterocytes and warping of the cytoplasmic membrane (steatosis); in some cases, lipid droplets were also present within the Golgi apparatus.In conclusion, the results of this trial suggest that the diet for S. solea juveniles should include no more than 12% lipids. Higher lipid inclusions not only led to a substantial decline in performance but also affected gut health. This should be taken into consideration in formulating specific practical diets for common sole.

Retrovirus Pseudomembranous Atrophic Enteritis caused by Suicidal Emperipolesis; A Light and Ultrastructural Study

Benign retroviral infections are common but are usually not recognized. This histologic and ultrastructural study identifies such an infection that became clinically evident in the small bowel following a partial colectomy for multiple micro invasive adenomas. Suspected is a low-grade retroviral infection of myeloid progenitor cells activated by inflammatory cytokines released by the operative procedure. Multiple infected neutrophils migrated to the small bowel adjacent to the operative anastomosis and through emperipolesis entered the luminal facing enterocytes. Budding of the retrovirus beginning at the neutrophil cell membrane within enterocytes assembled an immature retrovirus virus lacking a central core because translational and transcriptional viral events were not possible in the organelle poor and nuclear damaged neutrophils. Apoptosis of the infected neutrophil released toxic products and water produced in the mitochondria that distended the vacuoles encircling the neutrophils. There disruption spilled these contents directly into enterocyte cytoplasm producing collateral organelle injury that killed and detached surface enterocytes. This effaced the intestinal villi to produce atrophic and pseudomembranous enteritis with ulcers and bowel perforations. Conclusion: The incomplete assembly of retrovirus in neutrophils rendered the virus non-infective but suicidal emperipolesis in neutrophils assembling retrovirus grouped in enterocytes created the collateral damage that caused the enteritis. This article is the first to report this suicidal variant of emperipolesis and its causative retroviral enteritis.