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As the gastrointestinal tract may also be a crucial entry or interaction site of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the role of the gut mucosal immune system as a first-line physical and immunological defense is critical. Furthermore, gastrointestinal involvement and symptoms in coronavirus disease 2019 (COVID-19) patients have been linked to worse clinical outcomes. This review discusses recent data on the interactions between the virus and the immune cells and molecules in the mucosa during the infection. By carrying out appropriate investigations, the mucosal immune system role in SARS-CoV-2 infection in therapy and prevention can be established. In line with this, COVID-19 vaccines that stimulate mucosal immunity against the virus may have more advantages than the others.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the cause of the COVID-19 pandemic, is initiated by its binding to the ACE2 receptor and other co-receptors on mucosal epithelial cells. Variable outcomes of the infection and disease severity can be influenced by pre-existing risk factors. Human immunodeficiency virus (HIV), the cause of AIDS, targets the gut mucosal immune system and impairs epithelial barriers and mucosal immunity. We sought to determine the impact and mechanisms of pre-existing HIV infection increasing mucosal vulnerability to SARS-CoV-2 infection and disease. We investigated changes in the expression of ACE2 and other SARS-CoV-2 receptors and related pathways in virally inflamed gut by using the SIV infected rhesus macaque model of HIV/AIDS. Immunohistochemical analysis showed sustained/enhanced ACE2 expression in the gut epithelium of SIV infected animals compared to uninfected controls. Gut mucosal transcriptomic analysis demonstrated enhanced expression of host factors that support SARS-CoV-2 entry, replication, and infection. Metabolomic analysis of gut luminal contents revealed the impact of SIV infection as demonstrated by impaired mitochondrial function and decreased immune response, which render the host more vulnerable to other pathogens. In summary, SIV infection resulted in sustained or increased ACE2 expression in an inflamed and immune-impaired gut mucosal microenvironment. Collectively, these mucosal changes increase the susceptibility to SARS-CoV-2 infection and disease severity and result in ineffective viral clearance. Our study highlights the use of the SIV model of AIDS to fill the knowledge gap of the enteric mechanisms of co-infections as risk factors for poor disease outcomes, generation of new viral variants and immune escape in COVID-19.

The flagella of enteropathogenic Escherichia coli (EPEC) O127:H6 E2348/69 mediate adherence to host proteins and epithelial cells. What environmental and nutritional signals trigger or down-regulate flagella expression in EPEC are largely unknown. In this study, we analyzed the influence of pH, oxygen tension, cationic and anionic salts (including bile salt), carbon and nitrogen sources, and catecholamines on the expression of the flagellin gene (fliC) of E2348/69. We found that sodium bicarbonate, which has been shown to induce the expression of type III secretion effectors, down-regulated flagella expression, explaining why E2348/69 shows reduced motility and flagellation when growing in Dulbecco’s Minimal Essential Medium (DMEM). Further, growth under a 5% carbon dioxide atmosphere, in DMEM adjusted to pH 8.2, in M9 minimal medium supplemented with 80 mM glucose or sucrose, and in DMEM containing 150 mM sodium chloride, 0.1% sodium deoxycholate, or 30 µM epinephrine significantly enhanced fliC transcription to different levels in comparison to growth in DMEM alone. When EPEC was grown in the presence of HeLa cells or in supernatants of cultured HeLa cells, high levels (4-fold increase) of fliC transcription were detected in comparison to growth in DMEM alone. Our data suggest that nutritional and host signals that EPEC may encounter in the intestinal niche activate fliC expression in order to favor motility and host colonization.

Aims: A higher SGLT1 and GLUT2 gene expression was shown in the intestine of subjects with type 2 diabetes, while no data have been reported in type 1 diabetes (T1D). The purpose of our study was to evaluate the expression of glucose transporters in duodenal mucosa of subjects with T1D, compared to healthy controls (CTRL) and to patients with celiac disease (CD), as gut inflammatory disease control group. Materials and methods: Gene expression of GLUT1, GLUT2, SGLT1 and SGLT2 was quantified on duodenal mucosa biopsies of subjects with T1D (n = 19), CD (n = 16), T1D and CD (n = 6) and CTRL (n = 12), recruited at San Raffaele Hospital (Milan, Italy), between 2009 and 2018. SGLT2 expression was further evaluated by immunohistochemical and immunofluorescence staining. Results: The expression of all four glucose transporters was detected in duodenal mucosa of all groups. A reduced GLUT2, SGLT1 and SGLT2 expression was observed in CD in comparison with T1D and CTRL, as expected; GLUT1 was significantly more expressed in T1D compared to CTRL. SGLT2 expression was quantified at much lower levels than other transporters, with no differences between groups. SGLT2 expression was confirmed by immunohistochemistry in a restricted number of enterocytes lining in the mucosa of intestinal villi, also shown on immunofluorescence. Conclusions: Our results show that glucose transporters expression in duodenal mucosa of subjects with T1D, except an increased GLUT1, is not different from that observed in healthy controls. The expression of SGLT2 in human duodenal mucosa, although at low intensity, represents a novel finding.

The knowledge on how gut microbes contribute to the inflammatory bowel disease (IBD) at the onset of disease is still scarce. We compared gut microbiota in newly diagnosed, treatment-naïve adult IBD (Crohn's disease (CD) and ulcerative colitis (UC)) to irritable bowel syndrome (IBS) patients and healthy group. Mucosal and fecal microbiota of 49 patients (13 UC, 10 CD, and 26 IBS) before treatment initiation, and fecal microbiota of 12 healthy subjects was characterized by 16S rRNA gene sequencing. Mucosa was sampled at six positions, from terminal ileum to rectum. We demonstrate that mucosal microbiota is spatially homogeneous, cannot be differentiated based on the local inflammation status and yet provides bacterial footprints superior to fecal in discriminating disease phenotypes. IBD groups showed decreased bacterial diversity in mucosa at all taxonomic levels compared to IBS. In CD and UC, Dialister was significantly increased, and expansion of Haemophilus and Propionibacterium characterized UC. Compared to healthy individuals, fecal microbiota of IBD and IBS patients had increased abundance of Proteobacteria, Enterobacteriaceae, in particular. Shift toward reduction of Adlercreutzia and butyrate-producing taxa was found in feces of IBD patients. Microbiota alterations detected in newly diagnosed treatment-naïve adult patients indicate that the microbiota changes are set and detectable at the disease onset and likely have a discerning role in IBD pathophysiology. Our results justify further investigation of the taxa discriminating between disease groups, such as H. parainfluenzae, R. gnavus, Turicibacteriaceae, Dialister, and Adlercreutzia as potential biomarkers of the disease.

Complex dietary polysaccharides such as β-glucans are widely used for their anti-inflammatory properties. We reported before that oral administration of Yeast β-glucan (YBG) in adult mice can help delay type 1 diabetes (T1D) onset and suppress gut inflammation through modulation of the structure and function of gut microbiota. Since juvenile age is characterized by profoundly changing immature gut microbiota, we examined the impact of oral treatment with YBG in non-obese diabetic (NOD) mice at this age. Juvenile mice that received daily oral administration of YBG starting at 15 days of age for 7 or 30 days were examined for changes in gut microbiota, immune characteristics, and T1D incidence. Mice that received YBG for 30 days but not 7 days, showed considerable changes in the composition and diversity of fecal microbiota as compared to controls. Predictive functional analysis, based on 16S rDNA sequences, revealed overrepresentation of glycan biosynthesis and metabolism, energy metabolism, and fatty acid biosynthesis pathways in mice that received YBG for 30 days. Immune phenotype of the colon showed skewing toward immune regulatory and Th17 cytokines with increases in IL-10, IL-17, and IL-21 and a decrease in TNF-α, although increases in some pro-inflammatory cytokines (IL-1b, IFN-γ) were observed. Most importantly, mice that received YBG treatment for 30 days showed significantly suppressed insulitis and delayed onset of hyperglycemia compared to controls. Overall, this study suggests that oral consumption of YBG beginning at pre-diabetic juvenile ages could have positive maturational changes to gut microbiota and immune functions and could result in a delay in the disease onset in those who are pre-disposed to T1D.

While the human gut virome has been increasingly explored in recent years, nearly all studies have been limited to fecal sampling. The mucosal–luminal interface has been established as a viable sample type for profiling the microbial biogeography of the gastrointestinal tract. We have developed a protocol to extract nucleic acids from viruses at the mucosal–luminal interface of the proximal and distal colon. Colonic viromes from pediatric patients with Crohn's disease demonstrated high interpatient diversity and low but significant intrapatient variation between sites. Whole metagenomics was also performed to explore virome–bacteriome interactions and to compare the viral communities observed in virome and whole metagenomic sequencing. A site-specific study of the human gut virome is a necessary step to advance our understanding of virome–bacteriome–host interactions in human diseases.

Previously, we have shown that oral administration of yeast derived &beta, 1,3/1,6-d-glucan enhances immune regulation and alters the composition of the gut microbiota. However, it is not known if other structurally distinct &beta, glucans have similar properties. Here, using C57BL/6 mice, we show the potential of a microalgae derived &beta, 1,3-d-glucan, paramylon (PM), in shaping the gut microbiota and modulating the susceptibility to colitis. The community structure within the gut microbiota showed progressive changes including selective enrichment of specific communities and lowered community richness and diversity during prolonged oral treatment with PM. Compared to control mice, the gut microbiota of PM-treated mice had significantly higher abundance of Verrucomicrobia and lower abundance of Firmicutes. Specific taxa that were significantly more abundant in PM-treated mice include Akkermansia muciniphila and several Bacteroides members. Predictive functional analysis revealed overrepresentation of carbohydrate metabolism function in the fecal microbiota of PM recipients compared to controls, and this function was linked to Bacteroides spp. Prolonged pretreatment with PM not only diminished susceptibility to dextran sulfate sodium induced colitis severity, but also caused enhanced immune regulation. Overall, this study demonstrates the prebiotic properties of PM and the potential benefits of its prolonged oral consumption to gut health.

Detection of nutritional and noxious food components in the gut is a crucial component of gastrointestinal function. Contents in the gut lumen interact with enteroendocrine cells dispersed throughout the gut epithelium. Enteroendocrine cells release many different hormones, neuropeptides, and neurotransmitters that communicate either directly or indirectly with the central nervous system and the enteric nervous system, a network of neurons and glia located within the gut wall. Several populations of enteric neurons extend processes that innervate the gastrointestinal lamina propria; however, how these processes develop and begin to transmit information from the mucosa is not fully understood. In this study, we found that Tuj1-immunoreactive neurites begin to project out of the myenteric plexus at embryonic day (E)13.5 in the mouse small intestine, even before the formation of villi. Using live calcium imaging, we discovered that neurites were capable of transmitting electrical information from stimulated villi to the plexus by E15.5. In unpeeled gut preparations where all layers were left intact, we also mimicked the basolateral release of 5-HT from enteroendocrine cells, which triggered responses in myenteric cell bodies at postnatal day (P)0. Altogether, our results show that enteric neurons extend neurites out of the myenteric plexus early during mouse enteric nervous system development, innervating the gastrointestinal mucosa, even before villus formation in mice of either sex. Neurites are already able to conduct electrical information at E15.5, and responses to 5-HT develop postnatally.NEW & NOTEWORTHY How enteric neurons project into the gut mucosa and begin to communicate with the epithelium during development is not known. Our study shows that enteric neurites project into the lamina propria as early as E13.5 in the mouse, before development of the submucous plexus and before formation of intestinal villi. These neurites are capable of transmitting electrical signals back to their cell bodies by E15.5 and respond to serotonin applied to neurite terminals by birth. ispartof: AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY vol:318 issue:1 pages:G53-G65 ispartof: location:United States status: published

Summary Background Evidence suggests an important role for gut-microbiota dysbiosis in the development of rheumatoid arthritis (RA). The link between changes in gut bacteria and the development of joint inflammation is missing. Here, we address whether there are changes to the gut environment and how they contribute to arthritis pathogenesis. Methods We analyzed changes in markers of gut permeability, damage, and inflammation in peripheral blood and serum of RA patients. Serum, intestines, and lymphoid organs isolated from K/BxN mice with spontaneous arthritis or from wild-type, genetically modified interleukin (IL)-10R−/−or claudin-8−/−mice with induced arthritis were analyzed by immunofluorescence/histology, ELISA, and flow cytometry. Findings RA patients display increased levels of serum markers of gut permeability and damage and cellular gut-homing markers, both parameters positively correlating with disease severity. Arthritic mice display increased gut permeability from early stages of disease, as well as bacterial translocation, inflammatory gut damage, increases in interferon γ (IFNγ)+and decreases in IL-10+intestinal-infiltrating leukocyte frequency, and reduced intestinal epithelial IL-10R expression. Mechanistically, both arthritogenic bacteria and leukocytes are required to disrupt gut-barrier integrity. We show that exposing intestinal organoids to IFNγ reduces IL-10R expression by epithelial cells and that mice lacking epithelial IL-10R display increased intestinal permeability and exacerbated arthritis. Claudin-8−/−mice with constitutively increased gut permeability also develop worse joint disease. Treatment of mice with AT-1001, a molecule that prevents development of gut permeability, ameliorates arthritis. Conclusions We suggest that breakdown of gut-barrier integrity contributes to arthritis development and propose restoration of gut-barrier homeostasis as a new therapeutic approach for RA. Funding Funded by Versus Arthritis (21140 and 21257) and UKRI/MRC (MR/T000910/1)., Graphical abstract, Highlights Serum gut-permeability markers LPB, LPS, and I-FABP are increased in RA Mice with arthritis have increased gut permeability and intestinal inflammation Both bacteria and leukocytes are needed to disrupt gut-barrier integrity Prevention of gut-barrier dysfunction in arthritis ameliorates joint inflammation, Context and significance Rheumatoid arthritis is an autoimmune disorder characterized by chronic joint inflammation. Accumulating evidence suggests that changes in the composition of the bacteria residing in the gut could be responsible for joint inflammation. Currently, it is unclear how bacteria or their products instruct cells of the immune system to become harmful and induce arthritis. Researchers at University College London have shown that, in arthritis, there is profound damage to the gut lining, which fails to work properly as a barrier, as well as an accumulation in the gut of white blood cells that cause inflammation. The authors show that, in arthritis, bacteria cross the prohibited border of the intestinal lining and that repairing gut permeability defects with specific drugs inhibits joint inflammation., Changes to the gut bacteria have been associated with the development of arthritis; however, the mechanistic connection with disease remains unknown. Matei et al. identify pathological changes to the gut tissue in arthritis, including loss of gut-barrier integrity and inflammatory-cell infiltration, and show that restoration of gut homeostasis ameliorates disease.

[EN] The digestive tract, particularly the intestine, represents one of the main sites of interactions with the environment, playing the gut mucosa a crucial role in the digestion and absorption of nutrients, and in the immune defence. Previous researches have proven that the fishmeal replacement by plant sources could have an impact on the intestinal status at both digestive and immune level, compromising relevant productive parameters, such as feed efficiency, growth or survival. In order to evaluate the long-term impact of total fishmeal replacement on intestinal mucosa, the gut mucosa proteome was analysed in fish fed with a fishmeal-based diet, against plant protein-based diets with or without alternative marine sources inclusion. Total fishmeal replacement without marine ingredients inclusion, reported a negative impact in growth and biometric parameters, further an altered gut mucosa proteome. However, the inclusion of a low percentage of marine ingredients in plant protein-based diets was able to maintain the growth, biometrics parameters and gut mucosa proteome with similar values to FM group. A total fishmeal replacement induced a big set of underrepresented proteins in relation to several biological processes such as intracellular transport, assembly of cellular macrocomplex, protein localization and protein catabolism, as well as several molecular functions, mainly related with binding to different molecules and the maintenance of the cytoskeleton structure. The set of downregulated proteins also included molecules which have a crucial role in the maintenance of the normal function of the enterocytes, and therefore, of the epithelium, including permeability, immune and inflammatory response regulation and nutritional absorption. Possibly, the amino acid imbalance presented in VM diet, in a long-term feeding, may be the main reason of these alterations, which can be prevented by the inclusion of 15% of alternative marine sources. Significance: Long-term feeding with plant protein based diets may be considered as a stress factor and lead to a negative impact on digestive and immune system mechanisms at the gut, that can become apparent in a reduced fish performance. The need for fishmeal replacement by alternative ingredients such as plant sources to ensure the sustainability of the aquaculture sector has led the research assessing the intestinal status of fish to be of increasing importance. This scientific work provides further knowledge about the proteins and biologic processes altered in the gut in response to plant protein based diets, suggesting the loss of part of gut mucosa functionality. Nevertheless, the inclusion of alternative marine ingredients was able to reverse these negative effects, showing as a feasible option to develop sustainable aquafeeds., The first author was supported by a contract-grant (Contrato Pre doctoral para la Formacion de Profesorado Universitario) from Subprogramas de Formacion y Movilidad within the Programa Estatal de Promocion del Talento y su Empleabilidad of the Ministerio de Educacion, Cultura y Deporte of Spain.

ObjectiveThe pathogenesis of UC relates to gut microbiota dysbiosis. We postulate that alterations in the viral community populating the intestinal mucosa play an important role in UC pathogenesis. This study aims to characterise the mucosal virome and their functions in health and UC.DesignDeep metagenomics sequencing of virus-like particle preparations and bacterial 16S rRNA sequencing were performed on the rectal mucosa of 167 subjects from three different geographical regions in China (UC=91; healthy controls=76). Virome and bacteriome alterations in UC mucosa were assessed and correlated with patient metadata. We applied partition around medoids clustering algorithm and classified mucosa viral communities into two clusters, referred to as mucosal virome metacommunities 1 and 2.ResultsIn UC, there was an expansion of mucosa viruses, particularly Caudovirales bacteriophages, and a decrease in mucosa Caudovirales diversity, richness and evenness compared with healthy controls. Altered mucosal virome correlated with intestinal inflammation. Interindividual dissimilarity between mucosal viromes was higher in UC than controls. Escherichia phage and Enterobacteria phage were more abundant in the mucosa of UC than controls. Compared with metacommunity 1, metacommunity 2 was predominated by UC subjects and displayed a significant loss of various viral species. Patients with UC showed substantial abrogation of diverse viral functions, whereas multiple viral functions, particularly functions of bacteriophages associated with host bacteria fitness and pathogenicity, were markedly enriched in UC mucosa. Intensive transkingdom correlations between mucosa viruses and bacteria were significantly depleted in UC.ConclusionWe demonstrated for the first time that UC is characterised by substantial alterations of the mucosa virobiota with functional distortion. Enrichment of Caudovirales bacteriophages, increased phage/bacteria virulence functions and loss of viral-bacterial correlations in the UC mucosa highlight that mucosal virome may play an important role in UC pathogenesis.

Highlights • ATRA increased vaccine specific IgA in gut secretions to Vivotif but not Dukoral or Rotarix. • ATRA increased α4β7 and CCR9 gut marker expression in a coordinated manner only when given simultaneously with Vivotif vaccine. • In individuals with coordinated gut marker expression Vivotif specific IgA increase was much stronger., All-trans retinoic acid (ATRA) up-regulates, in laboratory animals, the expression of the gut homing markers α4β7 integrin and CCR9 on lymphocytes, increasing their gut tropism. Here, we show that, in healthy adult volunteers, ATRA induced an increase of these gut homing markers on T cells in vivo in a time dependent manner. The coordinated increase of α4β7 and CCR9 by ATRA was seen in 57% (12/21) of volunteers and only when given together with an oral Vivotif vaccine. When this coordinated response to ATRA and Vivotif vaccine was present, it was strongly correlated with the gut immunoglobulin A (IgA) specific response to vaccine LPS (ρ = 0.82; P = 0.02). Using RNA-Seq analysis of whole blood transcription, patients receiving ATRA and Vivotif in conjunction showed transcriptomic changes in immune-related pathways, particularly including interferon α/β signaling pathway, membrane-ECM interactions and immune hubs. These results suggest that exogenous ATRA can be used to manipulate responses to a subclass of oral vaccines, so far limited to a live attenuated Vivotif vaccine.

Cow’s milk fermented with Lactobacillus paracasei CBA L74 (FM-CBAL74) exerts a preventive effect against infectious diseases in children. We evaluated if this effect is at least in part related to a direct modulation of non-immune and immune defence mechanisms in human enterocytes. Human enterocytes (Caco-2) were stimulated for 48 h with FM-CBAL74 at different concentrations. Cell growth was assessed by colorimetric assay; cell differentiation (assessed by lactase expression), tight junction proteins (zonula occludens1 and occludin), mucin 2, and toll-like receptor (TRL) pathways were analysed by real-time PCR; innate immunity peptide synthesis, beta-defensin-2 (HBD-2) and cathelicidin (LL-37) were evaluated by ELISA. Mucus layer thickness was analysed by histochemistry. FMCBA L74 stimulated cell growth and differentiation, tight junction proteins and mucin 2 expression, and mucus layer thickness in a dose-dependent fashion. A significant stimulation of HBD-2 and LL-37 synthesis, associated with a modulation of TLR pathway, was also observed. FM-CBAL74 regulates non-immune and immune defence mechanisms through a direct interaction with the enterocytes. These effects could be involved in the preventive action against infectious diseases demonstrated by this fermented product in children.

Few current vaccines can establish antigen (Ag)-specific immune responses in both mucosal and systemic compartments. Therefore, development of vaccines providing defense against diverse infectious agents in both compartments is of high priority in global health. Intramuscular vaccination of an adenovirus vector (Adv) has been shown to induce Ag-specific cytotoxic T lymphocytes (CTLs) in both systemic and gut-mucosal compartments. We previously found that type I interferon (IFN) signaling is required for induction of gut-mucosal, but not systemic, CTLs following vaccination; however, the molecular mechanism involving type I IFN signaling remains unknown. Here, we found that T helper 17 (Th17)-polarizing cytokine expression was down-regulated in the inguinal lymph nodes (iLNs) of Ifnar2-/- mice, resulting in the reduction of Ag-specific Th17 cells in the iLNs and gut mucosa of the mice. We also found that prior transfer of Th17 cells reversed the decrease in the number of Ag-specific gut-mucosal CTLs in Ifnar2-/- mice following Adv vaccination. Additionally, prior transfer of Th17 cells into wild-type mice enhanced the induction of Ag-specific CTLs in the gut mucosa, but not in systemic compartments, suggesting a gut mucosa-specific mechanism where Th17 cells regulate the magnitude of vaccine-elicited Ag-specific CTL responses. These data suggest that Th17 cells translate systemic type I IFN signaling into a gut-mucosal CTL response following vaccination, which could promote the development of promising Adv vaccines capable of establishing both systemic and gut-mucosal protective immunity.

Copyright © 2017 Albuquerque, Fernandes, Tendeiro, Cheynier, Lucas, Silva, Victorino and Sousa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms., Chronic granulomatous disease (CGD) results from primary defects in phagocytic reactive oxygen species (ROS) production. T-cell evaluation is usually neglected during patients' follow-up, although T-cell depletion has been reported in CGD through unknown mechanisms. We describe here a 36-year-old patient with X-linked CGD with severe CD4 T-cell depletion, AA, SF, RT, and SS received scholarships from Fundação para a Ciência e Tecnologia (FCT), Portugal.

Mucosal immune activation and altered serotonin metabolism participate in the pathophysiology of irritable bowel syndrome (IBS). However, the reciprocal interplay between these two systems remains unknown. We evaluated the expression and release of interferon (IFN)-γ from the colonic mucosa of patients with IBS and its impact on serotonin reuptake transporter ( SERT) gene expression in Caco-2 cells. qPCR was used to evaluate IFN-γ gene expression in colonic mucosal biopsies, whereas IFN-γ protein amount was assessed by ELISA. Colonic T box expressed in T cells (T-bet) and phosphorylated signal transducer and activator of transcription 4 protein amount were evaluated by Western blot. The impact of colonic mucosal mediators on SERT gene expression was evaluated in Caco-2 cells using qPCR. IFN-γ receptor was silenced in Caco-2 cells to determine the effect of IFN-γ released by mucosal biopsies. Compared with asymptomatic controls (ACs), the expression of IFN-γ gene and its transcription factor T-bet were markedly increased in the colonic mucosa of patients with IBS. Compared with ACs, IFN-γ protein tissue levels and its release by mucosal biopsies were significantly increased in IBS. The exposure of Caco-2 cells to IBS supernatants induced a significant decrease in SERT gene expression, independently of IBS subtypes, compared with AC mucosal supernatants. In Caco-2 cells, IFN-γ receptor silencing reversed the reduction of SERT expression evoked by IBS supernatants vs. nonsilenced cell lines. IFN-γ gene, its transcription factor T-bet, IFN-γ protein expression, and its release are increased in the colonic mucosa of patients with IBS and downregulate SERT gene expression in vitro. These results suggest that IFN-γ downregulates SERT expression, hence likely playing a role in altered serotonin metabolism of patients with IBS.

Substantial clinical and animal evidences indicate that the mesenteric circulatory bed, particularly the gut mucosa, is highly vulnerable to reductions in oxygen supply and prone to early injury in the course of hemodynamic changes induced by sepsis and septic shock. Gut hypoxia or ischemia is one possible contributing factor to gastrointestinal tract barrier dysfunction that may be associated with the development of systemic inflammatory response and multiple organ dysfunction syndrome, the principal cause of death after sepsis. Monitoring gut perfusion during experimental and clinical sepsis may provide valuable insights over new interventions and therapies highly needed to reduce multiple organ dysfunction and sepsis-related morbidity and mortality. We present our experience with gas tonometry as a monitor of the adequacy of gastrointestinal mucosal perfusion in experimental models sepsis and with the use of vasoactive agents for hemodynamic management in patients with septic shock.Evidências clínicas e experimentais substanciais indicam que o território circulatório mesentérico, principalmente na mucosa intestinal, é altamente vulnerável a redução na oferta de oxigênio e predisposto a lesão precoce na presença de alterações hemodinâmicas induzidas pela sepse e choque séptico. A hipóxia ou isquemia intestinal é um dos possíveis mecanismos contribuintes para a disfunção da barreira gastrointestinal que pode estar associada com o desenvolvimento da resposta inflamatória sistêmica e com a síndrome da disfunção de múltiplos órgãos, a principal causa comum de morte na sepse. Monitorar a perfusão intestinal na sepse experimental e clínica pode fornecer dados valiosos quanto a novas intervenções e tratamentos altamente necessários para reduzir disfunção de múltiplos órgãos e mortalidade extremamente elevadas na sepse. Apresentamos nossa experiência com a tonometria a gás como monitor da adequação da perfusão da mucosa gastrointestinal na sepse clínica e experimental, e com o uso de drogas vasoativas no controle hemodinâmico em pacientes com choque séptico.

Evidencias clinicas e experimentais substanciais indicam que o territorio circulatorio mesenterico, principalmente na mucosa intestinal, e altamente vulneravel a reducao na oferta de oxigenio e predisposto a lesao precoce na presenca de alteracoes hemodinâmicas induzidas pela sepse e choque septico. A hipoxia ou isquemia intestinal e um dos possiveis mecanismos contribuintes para a disfuncao da barreira gastrointestinal que pode estar associada com o desenvolvimento da resposta inflamatoria sistemica e com a sindrome da disfuncao de multiplos orgaos, a principal causa comum de morte na sepse. Monitorar a perfusao intestinal na sepse experimental e clinica pode fornecer dados valiosos quanto a novas intervencoes e tratamentos altamente necessarios para reduzir disfuncao de multiplos orgaos e mortalidade extremamente elevadas na sepse. Apresentamos nossa experiencia com a tonometria a gas como monitor da adequacao da perfusao da mucosa gastrointestinal na sepse clinica e experimental, e com o uso de drogas vasoativas no controle hemodinâmico em pacientes com choque septico.

Substantial clinical and animal evidences indicate that the mesenteric circulatory bed, particularly the gut mucosa, is highly vulnerable to reductions in oxygen supply and prone to early injury in the course of hemodynamic changes induced by sepsis and septic shock. Gut hypoxia or ischemia is one possible contributing factor to gastrointestinal tract barrier dysfunction that may be associated with the development of systemic inflammatory response and multiple organ dysfunction syndrome, the principal cause of death after sepsis. Monitoring gut perfusion during experimental and clinical sepsis may provide valuable insights over new interventions and therapies highly needed to reduce multiple organ dysfunction and sepsis-related morbidity and mortality. We present our experience with gas tonometry as a monitor of the adequacy of gastrointestinal mucosal perfusion in experimental models sepsis and with the use of vasoactive agents for hemodynamic management in patients with septic shock.

The importance of B-isoform of leptin receptor (LEPR-B) signaling in the hypothalamus, pancreas, or liver has been well characterized, but in the intestine, a unique site of entry for dietary nutrition into the body, it has been relatively ignored. To address this question, we characterized a mouse model deficient for LEPR-B specifically in intestinal epithelial cells (IECs). IECLEPR-B-knockout (KO) and wild-type (WT) mice were generated by Cre-Lox strategy and fed a normal or high-fat diet (HFD). The analyses of the animals involved histology and immunohistochemistry of intestinal mucosa, indirect calorimetric measurements, whole-body composition, and expression and activities of nutrient transporters. IECLEPR-B-KO mice exhibited a 2-fold increase in length of jejunal villi and have normal growth on a normal diet but were less susceptible (P

By using immunohistology and digital image analysis for histomorphometry, we investigated the influence of porcine postnatal development on distribution and quantitative patterns of naïve/memory lymphoid cell subsets (CD45RA+, CD45RC+, respectively), helper/cytotoxic T cell subsets (CD4+, CD8+, respectively) as well as of IgA+ plasma cells in the gut-associated lymphoid tissues (GALT) of pigs reared under intensive conditions during the first 7 weeks of life. Current research on the postnatal ontogenesis/maturation of porcine small intestinal mucosal immune system have shown that newborn pigs are immunologically rather immature and, thus, totally dependent on passively acquired immunity. Their jejunal mucosa almost lacks immune cells, with the exception of a low number of CD45RA+ lymphoid cells (1.25×10-5) at Day 0 post partum. A very few CD45RC+ lymphoid cells (8.79×10-6 ) appeared at Day 7, followed by a similar number of IgA+ plasma cells (7.65×10-6) which were observed at Day 14. Such first signs of the postnatal development of both innate and adaptive immunity by identification/localization of tested cell subsets residing porcine GALT, i e. jejunal mucosal sites are proceeded by a lag period of three weeks until the appearance of low quantities of CD4+ (3.62×10-5) and CD8+ (3.13×10-5) T cells at Day 35 after birth. After that phase of early postnatal development of the crucial cell subsets participating in the antigen-specific immunity on the gut mucosal surfaces of young pigs, further progress was visible through their different distribution patterns within the jejunal mucosa compartments, and a gradual increase in their numbers, particularly between Day 35 and Day 49 of age. A significant increase was recorded within that period in the numbers of naïve, memory and plasma cells, whereas the number of helper and cytotoxic T cells only slightly increased between Day 42 and Day 49 of life., Pomoću imunohistoloških i histomorfometrijskih analiza računalnom obradom slike istraživali smo utjecaj postnatalnog razvitka u svinje na distribucijske i kvantitativne pokazatelje subpopulacija djevičanskih/ memorijskih limfoidnih stanica (CD45RA+ odnosno CD45RC+), pomoćničkih/citotoksičnih T-stanica (CD4+ odnosno CD8+), kao i za IgA+ plazma stanice u limfatičkim tkivima probavnog sustava (LTPS) prasadi uzgajane u intenzivnim uvjetima tijekom prvih 7 tjedana života. Istraživanje postnatalnog razvitka/sazrijevanja imunosnog sustava sluznice tankoga crijeva svinje pokazalo je da je neonatalna prasad imunološki prilično nezrela, pa je stoga u potpunosti ovisna o pasivno stečenoj imunosti. U sluznici njihovog jejunuma gotovo potpuno nedostaju imunosne stanice, s izuzetkom malobrojnih CD45 RA+ limfoidnih stanica (1,2510–5) 0. dana nakon prasenja. Sedmog dana post partum pojavljuje se nešto malo CD45RC+ limfoidnih stanica (8,7910-6), a potom se 14. dana mogu identificirati malobrojne IgA+ plazma stanice (7,650-6). Ovi prvi znakovi postnatalnog razvitka urođene i stečene imunosti, temeljem identifi kacije/lokalizacije subpopulacija istraživanih stanica koje naseljavaju LTPS svinje, odnosno sluznicu jejunuma, nastavljaju se nakon razdoblja od tri tjedna do pojavljivanja malobrojnih CD4+ (3,6210-5) i CD8+ (3,13 10-5) T-stanica 35. dana nakon prasenja. Nakon ove faze ranog postnatalnog razvitka ključnih subpopulacija stanica koje sudjeluju u antigenski specifičnoj imunosti na sluzničkim površinama crijeva mlade prasadi, daljnji je napredak vidljiv u različitosti obrazaca njihove raspodjele u odjeljcima sluznice jejunuma i postupnom porastu njihove brojnosti, napose između 35. i 49. dana starosti. Tijekom tog razdoblja zabilježen je značajan porast brojnosti djevičanskih, memorijskih i plazma stanica, dok je brojnost pomoćničkih i citotoksičnih T-stanica samo blago porasla između 42. i 49. dana života.

By using immunohistology and digital image analysis for histomorphometry we have investigated the influence of porcine postnatal development on distribution and quantitative patterns of naïve/memory lymphoid cell subsets (CD45RA+, CD45RC+, respectively), helper/cytotoxic T cell subsets (CD4+, CD8+, respectively) as well as of IgA+ plasma cells in the gut-associated lymphoid tissues (GALT) of the pigs reared under intensive conditions during the first 7 weeks of life. Current research on postnatal ontogenesis/maturation of porcine small intestinal mucosal immune system have shown that the newborn pigs were immunologically rather immature and, thus, totally dependent on passively acquired immunity. Their jejunal mucosa almost lack the immune cells, with exception of a low number of CD45RA+ lymphoid cells (1.25 x 10-5) at Day 0 post partum. A very few CD45RC+ lymphoid cells (8.79 x 10-6 ) appeared at Day 7 followed by a similar number of IgA+ plasma cells (7.65 x 10-6) which were observed at Day 14. Such first signs of postnatal development of both innate and adaptive immunity by identification/localization of tested cell subsets residing porcine GALT, i e. jejunal mucosal sites are proceeded with a lag period of three weeks until appearance of low numbers of CD4+ (3.62 x 10-5) and CD8+ (3.13 x 10-5) T cells at Day 35 after birth. After that phase of an early postnatal development of the crucial cell subsets participating in the antigen-specific immunity at the gut mucosal surfaces of young pigs, further progress is visible through their different distribution patterns within jejunal mucosa compartments and gradual increase in their numbers particularly between Day 35 and Day 49 of age. A significant increase was recorded within that period for the numbers of naïve, memory and plasma cells whereas the numbers of helper and cytotoxic T cells were only slightly increased between Day 42 and Day 49 of life

Oral tolerance is a phenomenon that may occur in animals exposed to protein antigens for the first time by the oral route. They become unable to produce immune responses at the levels normally observed when they are immunized parenterally with antigen in the presence of adjuvants. Lipids have been used as adjuvants for both parenteral and oral immunization. In the present study we coupled ovalbumin with palmitate residues by incubating the protein with the N-hydroxysuccinimide palmitate ester and tested the preparation for its ability to induce oral tolerance. This was performed by giving 20 mg of antigen to mice by the oral route 7 days prior to parenteral immunization in the presence of Al(OH)3. Mice were bled one week after receiving a booster that was given 2 weeks after primary immunization. Specific antibodies were detected by ELISA. Despite the fact that the conjugates are as immunogenic as the unmodified protein when parenterally injected in mice, they failed to induce oral tolerance. This discrepancy could be explained by differences in the intestinal absorption of the two forms of the antigen. In fact, when compared to the non-conjugated ovalbumin, a fast and high absorption of the lipid-conjugated form of ovalbumin was observed by "sandwich" ELISA.

Substantial clinical and animal evidences indicate that the mesenteric circulatory bed, particularly the gut mucosa, is highly vulnerable to reductions in oxygen supply and prone to early injury in the course of hemodynamic changes induced by sepsis and septic shock. Gut hypoxia or ischemia is one possible contributing factor to gastrointestinal tract barrier dysfunction that may be associated with the development of systemic inflammatory response and multiple organ dysfunction syndrome, the principal cause of death after sepsis. Monitoring gut perfusion during experimental and clinical sepsis may provide valuable insights over new interventions and therapies highly needed to reduce multiple organ dysfunction and sepsis-related morbidity and mortality. We present our experience with gas tonometry as a monitor of the adequacy of gastrointestinal mucosal perfusion in experimental models sepsis and with the use of vasoactive agents for hemodynamic management in patients with septic shock. Evidências clínicas e experimentais substanciais indicam que o território circulatório mesentérico, principalmente na mucosa intestinal, é altamente vulnerável a redução na oferta de oxigênio e predisposto a lesão precoce na presença de alterações hemodinâmicas induzidas pela sepse e choque séptico. A hipóxia ou isquemia intestinal é um dos possíveis mecanismos contribuintes para a disfunção da barreira gastrointestinal que pode estar associada com o desenvolvimento da resposta inflamatória sistêmica e com a síndrome da disfunção de múltiplos órgãos, a principal causa comum de morte na sepse. Monitorar a perfusão intestinal na sepse experimental e clínica pode fornecer dados valiosos quanto a novas intervenções e tratamentos altamente necessários para reduzir disfunção de múltiplos órgãos e mortalidade extremamente elevadas na sepse. Apresentamos nossa experiência com a tonometria a gás como monitor da adequação da perfusão da mucosa gastrointestinal na sepse clínica e experimental, e com o uso de drogas vasoativas no controle hemodinâmico em pacientes com choque séptico.

Substantial clinical and animal evidences indicate that the mesenteric circulatory bed, particularly the gut mucosa, is highly vulnerable to reductions in oxygen supply and prone to early injury in the course of hemodynamic changes induced by trauma, shock, sepsis and several complex surgical maneuvers. Gut hypoxia or ischemia is one possible contributing factor to gastrointestinal tract barrier dysfunction that may be associated with the development of systemic inflammatory response and multiple organ dysfunction syndrome, a common cause of death after trauma, sepsis or major surgeries. Monitoring gut perfusion during experiments may provide valuable insights over new interventions and therapies highly needed to reduce trauma and sepsis-related morbidity and mortality. We present our experience with gas tonometry as a monitor of the adequacy of gastrointestinal mucosal perfusion in clinical and experimental models of trauma, shock and surgical maneuvers associated with abrupt hemodynamic changes, such as aortic occlusion and hepatic vascular exclusion. Next issue we will be presenting our experience with gas tonometry in experimental and clinical sepsis. Evidências clínicas e experimentais substanciais indicam que o território circulatório mesentérico, principalmente na mucosa intestinal, é altamente vulnerável a redução na oferta de oxigênio e predisposto a lesão precoce na presença de alterações hemodinâmicas induzidas por trauma, choque, sepse e diversas manobras cirúrgicas complexas. A hipóxia ou isquemia intestinal é um dos possíveis mecanismos contribuintes para a disfunção da barreira gastrointestinal que pode estar associada com o desenvolvimento da resposta inflamatória sistêmica e com a síndrome da disfunção de múltiplos órgãos, causa comum de morte após trauma, sepse ou cirurgias de grande porte. Monitorar a perfusão intestinal em experimentos pode fornecer dados valiosos quanto a novas intervenções e tratamentos altamente necessários para reduzir a morbidade e mortalidade extremamente elevadas no trauma e na sepse. Apresentamos nossa experiência com a tonometria a gás como monitor da adequação da perfusão da mucosa gastrointestinal clínica e experimental, em modelos de trauma, sepse, e manobras cirúrgicas complexas tais como a oclusão da aorta e a exclusão vascular hepática.

HIV quasispecies was analysed in plasma and proviral genomes hosted by duodenal mucosa and peripheral blood cells (PBMC) from patients with early or chronic infection, with respect to viral heterogeneity, tropism compartmentalization and extent of immune activation. Seventeen HIV-1-infected combined antiretroviral therapy naive patients were enrolled (11 early infection and six chronic infection). V3 and nef genomic regions were analysed by ultra-deep pyrosequencing. Sequences were used to infer co-receptor usage and to construct phylogenetic trees. As markers of immune activation, plasma sCD14 and soluble tumour necrosis factor receptor II (sTNFRII) levels were measured. Median diversity of HIV RNA was lower in patients with early infection versus chronic infection patients. Overall, direct correlation was observed between V3 diversity and X4 frequency; V3 diversity of HIV RNA was inversely correlated with CD4 T-cell count; median sCD14 and sTNFRII values were similar in early and chronic patients, but X4 frequency of HIV RNA was directly correlated with plasma sCD14. The proportion of patients harbouring X4 variants and median intra-patient X4 frequency of proviral genomes tended to be higher in chronic infection than early infection patients. More pronounced compartmentalization of proviral quasispecies in gut compared with PBMC samples was observed in patients with early infection compared with chronic patients. The loss of gut/PBMC compartmentalization in more advanced stages of HIV infection was confirmed by longitudinal observation. More studies are needed to understand the pathogenetic significance of early HIV quasispecies compartmentalization and progressive intermixing of viral variants in subsequent phases of the infection, as well as the role of immune activation in tropism switch.

This study investigated, for the first time, the integrated effects of dietary protein source and protein/carbohydrate (P/CH) ratio on gilthead seabream gut histomorphology, microbiota composition, digestive enzymes activity, and immunological and oxidative stress-related gene expressions. Four isolipidic diets: two fishmeal-based (FM) and two plant feedstuff (PF)-based diets, with P/CH ratios of 50/10 or 40/20 each (FM-P50/CH10; FM-P40/CH20; PF-P50/CH10; PF-P40/CH20), were tested. PF-based diets lead to more histomorphological alterations than FM-based diets. P/CH ratio had no relevant effect on gut histomorphology. Gut mucosa of fish fed PF-based diets presented a higher number of operational taxonomic units, and richness and diversity indices, while the P/CH ratio did not affect those parameters. The α-amylase activity was lower in fish fed with PF-based diets and in fish fed the P40/CH20 diets. Regarding the immune-related genes, only cyclooxygenase-2 was affected, being higher in fish fed the P50/CH10 diets than the P40/CH20 diets. Fish fed the FM-based diets presented higher expression of glutathione reductase and glutathione peroxidase, while fish fed the P50/CH10 diet had higher expression of superoxide dismutase. In conclusion, PF-based diets can compromise gut absorptive and digestive metabolism, but decreasing the dietary P/CH ratio had little effect on the parameters measured.