Mechanisms of antidiarrhoeal effects by diosmectite in human intestinal cells

Rotavirus (RV) induces diarrhoea through a sequence of enterotoxic and cytotoxic effects. The former are NSP4-dependent, induce calcium-dependent chloride secretion and involve oxidative stress. Diosmectite (DS) is a natural clay that has been recommended as an active therapy for diarrhoea, but the mechanism of its effect is not clear. Electrical parameters may be used to measure the direct enterotoxic and cytotoxic effects in polar epithelial intestinal cells. To investigate the effects of DS on RV-induced enterotoxic and cytotoxic damage. Caco-2 cells were used as a model of RV infection to evaluate chloride secretion, epithelial integrity, oxidative stress and viral infectivity in Ussing chambers

Early-Life Intestine Microbiota and Lung Health in Children

The gastrointestinal microbiota plays a critical role in nutritional, metabolic, and immune functions in infants and young children and has implications for future lung health status. Understanding the role of intestinal dysbiosis in chronic lung disease progression will provide opportunities to design early interventions to improve the course of the disease. Gut microbiota is established within the first 1 to 3 years of life and remains relatively stable throughout the life span. In this review, we report the recent development in research in gut-lung axis, with focus on the effects of targeting microbiota of infants and children at risk of or with progressive lung diseases. The basic concept is to exploit this approach in critical window to achieve the best results in the control of future health

Lactoferrin induces concentration-dependent functional modulation of intestinal proliferation and differentiation

Human milk stimulates intestinal development through the effects of various moieties. Lactoferrin (LF) is a glycoprotein of human milk whose concentration is highest in colostrum decreasing in mature milk. LF promotes enterocyte growth in intestinal cell lines. We tested the hypothesis that LF induces a distinct effect on enterocyte proliferation and differentiation, depending on its concentration. We examined the dose-related effects by human-native LF (N-LF) in Caco-2 (human colon adenocarcinoma) cells. At high concentrations, N-LF stimulated cell proliferation in immature Caco-2 cells, as judged by 3H-thymidine incorporation. In contrast, sucrase and lactase activities were increased at low but not high LF concentrations and their mRNA were also increased, indicating a transcriptional effect. Because iron binds specific LF sites, we compared the potency of N-LF and iron-saturated LF (I-LF) and found the native form more potent. Finally, we tested the effects by bovine LF (bLF) in the same system and found the latter more potent than the human isoform in inducing cell growth and lactase expression. These results suggest that LF directly induces enterocyte growth and proliferation, depending on its concentration, thereby regulating the earlyx postnatal intestinal development. bLF could be added to infant formula as a growth factor in selected intestinal disease

Guanylin and E.coli heat-stable enterotoxin induce chloride secretion through direct interaction with basolateral compartment of rat and human coloni cells.

We previously detected specific binding activity of Escherichia coli heat-stable enterotoxin (ST), the guanylin exogenous ligand, in rat colonic basolateral membranes. Because guanylin circulates in the bloodstream, we tested the hypothesis that it modulates intestinal ion transport by acting on the serosal side of intestinal cells. The effects of the mucosal and serosal addition of ST and guanylin on ion transport were investigated in the rat proximal colon and in Caco-2 cells in Ussing chambers, by monitoring short-circuit current (Isc). cGMP concentration was measured in Caco-2 cells by RIA. Mucosal ST addition induced an increase in Isc in rat proximal colon consistent with anion secretion. Serosal addition induced the same effects but to a lesser extent. The electrical effects observed in Caco-2 cells paralleled those observed in rat proximal colon. A pattern similar to the electrical response was observed with cGMP concentration. Guanylin addition to either side of Caco-2 cells induced the same effects as ST, although to a lesser extent. In all conditions, the electrical effect disappeared in the absence of chloride. ST directly interacts with basolateral receptors in the large intestine inducing chloride secretion through an increase of cGMP. However, the serosal effects are less pronounced compared with those observed with mucosal addition. Guanylin shows the same pattern, suggesting that it plays a role in the regulation of ion transport in the colon, but the relative importance of serosally mediated secretion remains to be determined

Rotavirus induces a biphasic enterotoxic and cytotoxic response in human-derived intestinal enterocytes, which is inhibited by human immunoglobulins.

The mechanisms of diarrhea due to rotavirus infection in humans are not fully understood; no specific therapy is available, but orally administered human serum immunoglobulins are effective in blocking stool output. We aimed to investigate the effect of rotavirus on ion transport and the role of NSP4 in human-derived enterocytes, and to test the efficacy of human serum immunoglobulin in a model of rotavirus infection. Soon after infection, rotavirus induces active chloride secretion in enterocytes. This effect is evident before viral replication leads to cell damage and correlates with NSP4 production. Inhibition of NSP4 prevents the early secretory phase but not cell damage. Incubation with human serum immunoglobulin blocks both ion secretion and cell damage. Rotavirus exerts an early NSP4-dependent ion secretion and subsequent tissue damage. The combined enterotoxic and cytotoxic effects may be responsible for the increased severity of diarrhea due to rotavirus infection, and both are counteracted by human serum immunoglobulin

Zinc inhibits calcium-mediated and nitric oxide-mediated ion secretion in human enterocytes

Zn2+ is effective in the treatment of acute diarrhea, but its mechanisms are not completely understood. We previously demonstrated that Zn2+ inhibits the secretory effect of cyclic adenosine monophosphate but not of cyclic guanosine monophosphate in human enterocytes. The aim of the present study was to investigate whether Zn2+ inhibits intestinal ion secretion mediated by the Ca2+ or nitric oxide pathways. To investigate ion transport we evaluated the effect of Zn2+ (35 μM) on electrical parameters of human intestinal epithelial cell monolayers (Caco2 cells) mounted in Ussing chambers and exposed to ligands that selectively increased intracellular Ca2+ (carbachol 10− 6 M) or nitric oxide (interferon-γ 300 UI/ml) concentrations. We also measured intracellular Ca2+ and nitric oxide concentrations. Zn2+ significantly reduced ion secretion elicited by carbachol (− 87%) or by interferon-γ (− 100%), and inhibited the increase of intracellular Ca2+ and nitric oxide concentrations. These data indicate that Zn2+ inhibits ion secretion elicited by Ca2+ and nitric oxide by directly interacting with the enterocyte. They also suggest that Zn2+ interferes with three of the four main intracellular pathways of intestinal ion secretion that are involved in acute diarrhe

Galacto-Oligosaccharide/Polidextrose Enriched Formula Protects against Respiratory Infections in Infants at High Risk of Atopy: A Randomized Clinical Trial

Early nutrition affects the risk of atopy and infections through modifications of intestinal microbiota. The Prebiotics in the Prevention of Atopy (PIPA) study was a 24-month randomised, double-blind, placebo-controlled trial. It aimed to evaluate the effects of a galacto-oligosaccharide/polydextrose (GOS/PDX)-formula (PF) on atopic dermatitis (AD) and common infections in infants who were born to atopic parents and to investigate the relationship among early nutrition, gut microbiota and clinical outcomes

Effect of synbiotic supplementation in children and adolescents with cystic fibrosis: a randomized controlled clinical trial

BACKGROUND/OBJECTIVES:Cystic fibrosis (CF) is characterized by excessive activation of immune processes. The aim of this study was to evaluate the effect of synbiotic supplementation on the inflammatory response in children/adolescents with CF. SUBJECTS/METHODS:A randomized, placebo-controlled, double-blind, clinical-trial was conducted with control group (CG, n = 17), placebo-CF-group (PCFG, n = 19), synbiotic CF-group (SCFG, n = 22), PCFG negative (n = 8) and positive (n = 11) bacteriology, and SCFG negative (n = 12) and positive (n = 10) bacteriology. Markers of lung function (FEV1), nutritional status [body mass index-for age (BMI/A), height-for-age (H/A), weight-for-age (W/A), upper-arm fat area (UFA), upper-arm muscle area (UMA), body fat (%BF)], and inflammation [interleukin (IL)-12, tumor necrosis factor-alpha (TNF-α), IL-10, IL-6, IL-1β, IL-8, myeloperoxidase (MPO), nitric oxide metabolites (NOx)] were evaluated before and after 90-day of supplementation with a synbiotic. RESULTS:No significance difference was found between the baseline and end evaluations of FEV1 and nutricional status markers. A significant interaction (time vs. group) was found for IL-12 (p = 0.010) and myeloperoxidase (p = 0.036) between PCFG and SCFG, however, the difference was not maintained after assessing the groups individually. NOx diminished significantly after supplementation in the SCFG (p = 0.030). In the SCFG with positive bacteriology, reductions were found in IL-6 (p = 0.033) and IL-8 (p = 0.009) after supplementation. CONCLUSIONS: Synbiotic supplementation shown promise at diminishing the pro-inflammatory markers IL-6, IL-8 in the SCFG with positive bacteriology and NOx in the SCFG in children/adolescents with CF