Dose-effect of interleukin-10 and its immunoregulatory role in Crohn's disease.

BACKGROUND: Interleukin-10 (IL-10) is currently being extensively studied in clinical trials for the treatment of Crohn's disease (CD). Only marginal effects have, however, been reported, and the dose-response curve was bell-shaped contrasting with the reported data from in vitro experiments. AIM: To use another in vitro model to analyze the effect of rhIL-10 and rhIL-4 on the spontaneous mucosal TNF-alpha secretion in patients with CD, and to characterize the phenotype of the cells targeted by rhIL-10. METHODS: Non-inflamed colon biopsies from CD patients were cultured for 16 hours in presence of different concentrations of rhIL-10 or rhIL-4. The numbers of TNF-alpha-secreting cells among isolated lamina propria mononuclear cells (LPMNC) were estimated by Elispot. RESULTS: Both rhIL-10 and rhIL-4 down-regulate TNF-alpha secretion by LPMNC from CD patients, with a more pronounced effect with rhIL-10. These effects were closely linked to the cytokine concentrations used, with a bell-shaped dose-response curve. Residual TNF-alpha secretion, in the presence of optimal rhIL-10 concentration was mainly attributable to CD3+ T cells. In contrast, at higher rhIL-10 concentrations, CD3- cells contributed significantly to the TNF-alpha secretion. CONCLUSIONS: The in vitro model we used, demonstrates that IL-4, but mostly IL-10, efficiently suppresses TNF-alpha secretion in LPMNC from CD patients, with a dose-response curve similar to results obtained in vivo. Resistance at high rhIL-10 concentrations was associated with a change in the phenotype of TNF-alpha-secreting cells.

Anti-CTLA-4 treatment induces IL-10-producing ICOS+ regulatory T cells displaying IDO-dependent anti-inflammatory properties in a mouse model of colitis.

BACKGROUND AND AIMS: Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) has been shown to act as a negative regulator of T cell function and has been implicated in the regulation of T helper 1 (Th1)/Th2 development and the function of regulatory T cells. Tests were carried out to determine whether anti-CTLA-4 treatment would alter the polarisation of naive T cells in vivo. METHODS: Mice were treated with anti-CTLA-4 monoclonal antibody (mAb) (UC10-4F10) at the time of immunisation or colonic instillation of trinitrobenzene sulfonic acid (TNBS). The cytokines produced by lymph node cells after in vitro antigenic stimulation and the role of indoleamine 2,3 dioxygenase (IDO) and of interleukin-10 (IL-10) were tested, and the survival of mice was monitored. RESULTS: Injection of anti-CTLA-4 mAb in mice during priming induced the development of adaptive CD4(+) regulatory T cells which expressed high levels of ICOS (inducible co-stimulator), secreted IL-4 and IL-10. This treatment inhibited Th1 memory responses in vivo and repressed experimental intestinal inflammation. The anti-CTLA-4-induced amelioration of disease correlated with IDO expression and infiltration of ICOS(high) Foxp3(+) T cells in the intestine, suggesting that anti-CTLA-4 acted indirectly through the development of regulatory T cells producing IL-10 and inducing IDO. CONCLUSIONS: These observations emphasise the synergy between IL-10 and IDO as anti-inflammatory agents and highlight anti-CTLA-4 treatment as a potential novel immunotherapeutic approach for inducing adaptive regulatory T cells.

Immunological evaluation of the intestinal mucosa of broiler chicks treated with Lactobacillus Spp. and challenged with Salmonella Enteritidis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of corn replacement by sorghum in broiler diets on performance and intestinal mucosa integrity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Intestinal mucosa development in broiler chickens fed natural growth promoters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Histomorphometric study of role of lactoferrin in atrophy of the intestinal mucosa of rats

The purpose of this work was to study the effects of oral administration of lactoferrin (Lf) in rats subjected to atrophy of the small intestine induced by a diet based on soy protein concentrate as the main protein source. We used 24 male Wistar rats aged 40 days, kept in individual cages under appropriate conditions of temperature, light and humidity. The animals were divided into four groups (n = 6); 1) group SL received soy-based food and, once a day, a supplement of 200mg/kg of Lf administered by gavage; 2) group Si received the soy feed without supplement of Lf; 3) group CL received a diet based on casein plus Lf; 4) group Ci received the casein diet without supplement of Lf. At the end of fifteen days, a 10 mm segment of the initial portion of the small intestine was sectioned and subjected to morphometry of the intestinal crypts and villi and assessment of the number and size of myofibroblasts. Comparison between groups showed that the length of the villi was similar in groups Ci and CL and higher in CL than in SL; SL than in Si, in Ci than in SL, and in Ci than in Si to Ci. The crypt depth was similar in SL and CL, SL and Ci and Ci and CL and was higher in Si than in Ci and in Si than in SL. The number of myofibroblasts was higher in SL than in CL, in SL than in Si, in CL than in Ci, and in SL than in and Ci; between Ci and Si there was no difference. The area of myofibroblasts was similar between the groups SL and CL and Si and Ci and higher in SL than in Si, and in Cl than in and Ci, and in SL than in Ci. All statistical analysis assumed significance when p < 0.05. From these results, we conclude that lactoferrin increases the number and size of the pericrypt myofibroblasts and stimulates rapidly the regeneration of atrophied villi.

Binding studies on isolated porcine small intestinal mucosa and in vitro toxicity studies reveal lack of effect of C. perfringens beta-toxin on the porcine intestinal epithelium

Beta-toxin (CPB) is the essential virulence factor of C. perfringens type C causing necrotizing enteritis (NE) in different hosts. Using a pig infection model, we showed that CPB targets small intestinal endothelial cells. Its effect on the porcine intestinal epithelium, however, could not be adequately investigated by this approach. Using porcine neonatal jejunal explants and cryosections, we performed in situ binding studies with CPB. We confirmed binding of CPB to endothelial but could not detect binding to epithelial cells. In contrast, the intact epithelial layer inhibited CPB penetration into deeper intestinal layers. CPB failed to induce cytopathic effects in cultured polarized porcine intestinal epithelial cells (IPEC-J2) and primary jejunal epithelial cells. C. perfringens type C culture supernatants were toxic for cell cultures. This, however, was not inhibited by CPB neutralization. Our results show that, in the porcine small intestine, CPB primarily targets endothelial cells and does not bind to epithelial cells. An intact intestinal epithelial layer prevents CPB diffusion into underlying tissue and CPB alone does not cause direct damage to intestinal epithelial cells. Additional factors might be involved in the early epithelial damage which is needed for CPB diffusion towards its endothelial targets in the small intestine.

Acylation of lysolecithin in the intestinal mucosa of rats

1. The presence of an active acyl-CoA–lysolecithin (1-acylglycerophosphorylcholine) acyltransferase was demonstrated in rat intestinal mucosa. 2. ATP and CoA were necessary for the incorporation of free [1-14C]oleic acid into lecithin (phosphatidylcholine). 3. The reaction was about 20 times as fast with [1-14C]oleoyl-CoA as with free oleic acid, CoA and ATP. 4. With 1-acylglycerophosphorylcholine as the acceptor, both oleic acid and palmitic acid were incorporated into the β-position of lecithin; the incorporation of palmitic acid was 60% of that of oleic acid. 5. Of the various analogues of lysolecithin tested as acyl acceptors from [1-14C]oleoyl CoA, a lysolecithin with a long-chain fatty acid at the 1-position was most efficient. 6. The enzyme was mostly present in the brush-border-free particulate fraction of the intestinal mucosa. 7. Of the various tissues of rats tested for the activity, intestinal mucosa was found to be the most active, with testes, liver, kidneys and spleen following it in decreasing order.

High cholesterol diet and esterification of cholesterol by the intestinal mucosa of rats

Young male rats maintained on a diet containing 1% cholesterol were sacrificed at the end of 1st, 2nd, 3rd, 5th, and 7th week. Acetone powders prepared from their intestinal mucosa and pancreas were tested for the synthetic and hydrolytic activities for Vitamin A and cholesterol esters. The esterifying activity of the mucosal enzymes for both Vitamin A and cholesterol increased progressively up to the end of the 5th week; the increase in esterification of cholesterol was more marked with respect to saturated fatty acids, as compared to the unsaturated ones. The pancreatic enzymes remained unaffected. It is suggested that one of the reasons for the accumulation of cholesterol esters in animal tissues may be the increased esterification of the sterol in the mucosa induced by dietary cholesterol.

Interaction of enterohemorrhagic Escherichia coli O157 : H7 with mouse intestinal mucosa

In this study, we used mouse ileal loops to investigate the interaction of enterohemorrhagic Escherichia coli (EHEC) O157:H7 with the mouse intestinal mucosa. With a dose of 10(9) and 3 h incubation, EHEC O157 was detected in the lumen and to a lesser extent associated with the epithelium. Typical attaching and effacing (A/E) lesions were seen, albeit infrequently. While the effector protein Tir was essential for A/E lesion formation, the bacterial type III secretion system adaptor protein TccP was dispensable. These results suggest that A/E lesions on mouse intestinal mucosa can be formed independently of robust actin polymerization.

Dendritic cells interact with CD4 T cells in intestinal mucosa

Absence of lymph nodes in nonmammalian species, expression of MHCII by APCs in the periphery, and the recent findings that T cells can change their polarization status after presentation in the lymph nodes imply a role for MHCII-mediated presentation outside the organized lymphoid tissue. This study shows that MHCII+ ECs and DCs from the intestinal mucosa of the pig can present antigen to T cells in vitro. In vivo, APCs colocalize with T cells in pig and mouse intestinal mucosa. In the pig, endothelium is involved in these interactions in neonates but not in adults, indicating different roles for stromal and professional APCs in the neonate compared with the adult. The ratio of expression of DQ and DR MHCII locus products was lower on ECs than on other mucosal APCs, indicating that the two types of cells present different peptide sets. Adult nonendothelial APCs expressed a higher ratio of DQ/DR than in neonates. These results suggest that mucosal DCs can present antigen locally to primed T cells and that stromal APCs are recruited to these interactions in some cases. This raises the possibility that local presentation may influence T cell responses at the effector stage after initial presentation in the lymph node.

Performance and intestinal mucosa development of broiler chickens fed diets containing Saccharomyces cerevisiae cell wall

Use of antibiotics as an additive in poultry diets to improve growth has been discussed in relation to bacterial resistance and the development of new products and management practices. This study was carried out to test the efficacy of a new substance (Saccharomyces cereviside cell walls, var. Calsberg- SCCW) obtained from the brewery industry, added (at 0.1 and 0.2%) to broiler chicken diets (based on corn and soybean meal), on performance and intestinal mucosa development. In Experiment 1 (carried out in litter-floor pens) the results revealed higher body weight gain,for the total experimental period and higher villus height at 7 d of age for the birds fed 0.2%,SCCW. In a field test using 44,000 broilers that,received feed containing 0.2% SCCW,. The results also showed higher body weight gain and better feed conversion for SCCW-supplemented birds. The present findings show that SCCW improved body weight gain in broiler chickens and that this effect can be attributed to the trophic effect of this product on the intestinal mucosa, because it increases villus height, particularly during the first 7. d of a chicken's life.