Effects of glutamine supplementation on gut barrier, glutathione content and acute phase response in malnourished rats during inflammatory shock.

AIM: To evaluate the effect of glutamine on intestinal mucosa integrity, glutathione stores and acute phase response in protein-depleted rats during an inflammatory shock. METHODS: Plasma acute phase proteins (APP), jejunal APP mRNA levels, liver and jejunal glutathione concentrations were measured before and one, three and seven days after turpentine injection in 4 groups of control, protein-restricted, protein-restricted rats supplemented with glutamine or protein powder. Bacterial translocation in mesenteric lymph nodes and intestinal morphology were also assessed. RESULTS: Protein deprivation and turpentine injection significantly reduced jejunal villus height, and crypt depths. Mucosal glutathione concentration significantly decreased in protein-restricted rats. Before turpentine oil, glutamine supplementation restored villus heights and glutathione concentration (3.24 +/- 1.05 vs 1.72 +/- 0.46 mumol/g tissue, P<0.05) in the jejunum, whereas in the liver glutathione remained low. Glutamine markedly increased jejunal alpha1-acid glycoprotein mRNA level after turpentine oil but did not affect its plasma concentration. Bacterial translocation in protein-restricted rats was not prevented by glutamine or protein powder supplementation. CONCLUSION: Glutamine restored gut glutathione stores and villus heights in malnourished rats but had no preventive effect on bacterial translocation in our model.

Survival of Lactobacillus casei in the human digestive tract after consumption of fermented milk.

A human trial was carried out to assess the ileal and fecal survival of Lactobacillus casei DN-114 001 ingested in fermented milk. Survival rates were up to 51.2% in the ileum and 28.4% in the feces. The probiotic bacterium has the capacity to survive during its transit through the human gut.

Effects of orally administered Lactobacillus casei DN-114 001 on the composition or activities of the dominant faecal microbiota in healthy humans.

The composition and activities of the faecal microbiota in twelve healthy subjects analysed in a single open study were monitored before (1-week baseline step), during (10 d supplementation step) and after (10 d follow-up step) the ingestion of a fermented milk containing Lactobacillus casei DN-114 001. Fluorescent in situ hybridisation with group-specific DNA probes, real-time PCR using L. paracasei group-specific primers and temporal temperature gradient gel electrophoresis (TTGE) using group-specific primers were carried out, together with bacterial enzyme activity and metabolite analyses to monitor the structure and activities of the faecal microbiota. L. casei DNA was detected in the faeces of all of the subjects by TTGE after 10 d supplementation. Its quantification by real-time PCR showed a 1000-fold increase during the test step compared with initial levels. No major modification in either the dominant members of the faecal microbiota or their activities was observed during the trial. In conclusion, the short-term consumption of a milk product containing L. casei DN-114 001 was accompanied by a high, transient increase in the quantity of this strain in the faeces of all of the subjects without markedly affecting biochemical or bacteriological factors.

Lactobacillus casei DN-114 001 inhibits the ability of adherent-invasive Escherichia coli isolated from Crohn's disease patients to adhere to and to invade intestinal epithelial cells.

Ileal lesions in 36.4% of patients with Crohn's disease are colonized by pathogenic adherent-invasive Escherichia coli. The aim of this study was to determine the in vitro inhibitory effects of the probiotic strain, Lactobacillus casei DN-114 001, on adhesion to and invasion of human intestinal epithelial cells by adherent-invasive E. coli isolated from Crohn's disease patients. The experiments were performed with undifferentiated Intestine-407 cells and with undifferentiated or differentiated Caco-2 intestinal epithelial cells. Bacterial adhesion to and invasion of intestinal epithelial cells were assessed by counting CFU. The inhibitory effects of L. casei were determined after coincubation with adherent-invasive E. coli or after preincubation of intestinal cells with L. casei prior to infection with adherent-invasive E. coli. Inhibitory effects of L. casei on adherent-invasive E. coli adhesion to differentiated and undifferentiated intestinal epithelial cells reached 75% to 84% in coincubation and 43% to 62% in preincubation experiments, according to the cell lines used. Addition of L. casei culture supernatant to the incubation medium increased L. casei adhesion to intestinal epithelial cells and enhanced the inhibitory effects of L. casei. The inhibitory effects on E. coli invasion paralleled those on adhesion. This effect was not due to a bactericidal effect on adherent-invasive E. coli or to a cytotoxic effect on epithelial intestinal cells. As Lactobacillus casei DN-114 001 strongly inhibits interaction of adherent-invasive E. coli with intestinal epithelial cells, this finding suggests that the probiotic strain could be of therapeutic value in Crohn's disease.

Acute enteral glutamine infusion enhances heme oxygenase-1 expression in human duodenal mucosa.

The heat shock protein, heme oxygenase-1 (HO-1), contributes to the protection of the intestine. Some experimental models suggest that induction of HO-1 by glutamine may contribute to the preservation of intestinal mucosa. The effect of an enteral infusion of glutamine for 6 h on HO-1 expression in duodenal mucosa was studied in healthy men and women and compared with an isonitrogenous mixture of amino acids. After enteral infusion, endoscopic duodenal biopsies were performed and either fixed in formalin for immunohistochemistry or frozen for HO-1 mRNA analysis by reverse transcriptase-polymerase chain reaction. Histologic examination revealed that HO-1 was constitutively expressed in intestinal epithelial cells (IEC), and that glutamine increased the grade of HO-1 immunostaining (P

Glutamine decreases interleukin-8 and interleukin-6 but not nitric oxide and prostaglandins e(2) production by human gut in-vitro.

BACKGROUND: Glutamine modulates cytokine production in various tissues but its effects on the production of other inflammatory mediators such as eicosanoids and nitric oxide have not been investigated in human gut. AIM: To evaluate the influence of glutamine on interleukin (IL)-8, IL-6, nitric oxide and prostaglandin E(2) production by human gut. METHODS: Ten fasted volunteers received either enteral glutamine or isonitrogenous amino acids over 6 h in a cross-over design. Series of duodenal biopsies were frozen or cultured for 24 h with 0.5 or 5 mM of glutamine or amino acids. IL-6, IL-8 and PGE(2) were measured in culture media by ELISA and nitrites by Griess assay. mRNA levels for IL-6, IL-8, Cyclooxygenase-2 and NO synthase-2 were assessed in biopsies by RT-PCR. Results in percent, (median [range]) were compared by Wilcoxon test. RESULTS: Glutamine decreased IL-8 and IL-6 in-vitro production: 63 [2-173] vs 100 [19-177] and 37 [5-489] vs 100 [33-431], both P<0.05. IL-8 mRNA level also decreased in biopsies cultured with 5 mM glutamine: 26 [13-142] vs 92 [34-215], P<0.05. Nitrites and PGE(2) concentrations were not significantly affected by glutamine. CONCLUSION: Glutamine has a specific inhibitory effect on pro-inflammatory cytokine production in the gut and may contribution to the modulation of intestinal inflammation.