ß-Carotene improves intestinal barrier function by modulating proinflammatory cytokines and improving antioxidant capacity in ß-lactoglobulin-sensitized mice.

Increased intestinal permeability due to barrier dysfunction is supposed to cause several gastrointestinal diseases. We have previously demonstrated that a single ß-carotene (BC) dose protects against increase in anaphylactic response in ß-lactoglobulin (BLG)-sensitized mice with no effect on the epithelial permeability and weak recovery of villi length. Utilizing the same murine ex vivo intestinal model, the aim of this study was to investigate the effect of different BC doses on BLG-mediated intestinal epithelial barrier disturbances. Jejunum was harvested from BLG-sensitized mice pretreated with either one of three different doses of BC (5, 10 and 20 mg/ kg body weight) and mounted on Ussing Chambers. Transepithelial electrical resistance (TER) and short-circuit current (Isc) were recorded as indicators of intestinal epithelial barrier function. Histopathological analysis of the intestine was carried out for the control and experimental mice. TNF-α and IL-6 levels were determined in serum using ELISA, and the analysis of antioxidant activity was performed for reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS). BC was capable of enhancing the intestinal barrier function, as indicated by the increased TER and the decreased Isc. Intestinal damage characterized by the shortening of villi and infiltration of intestinal lymphocytes was significantly reversed by BC pretreatment. Such effects of BC were accompanied by a reduction in the levels of IL-6 and TBARS and an increase of GSH. TNF-α levels were reduced only at the lowest BC dose. These findings may encourage the use of BC-based therapies for controlling the breakdown of the intestinal barrier in vivo.

Taurine administration prevents the intestine from the damage induced by beta-lactoglobulin sensitization in a murine model of food allergy

Background: Allergy to cow's milk proteins has often been associated with dysfunction of the intestinal mucosa caused by chronic inflammation in infants. This study evaluated the protective effect of taurine on intestinal damage induced by beta-lactoglobulin (Beta-Lg) in Balb/c mice used as an animal model of allergy to cow's milk proteins. Methods: Balb/c mice were treated with taurine administered orally by gavage (3 mmol/kg/day) or intraperitoneally (100 mg/kg/day) for two weeks, then sensitized intraperitoneally with Beta-Lg. The electrophysiological parameters: active ion transport of chloride (Short-circuit current: Isc) and the passive ion permeability (Conductance: G) were measured ex vivo in Ussing chamber by intestine challenge with Beta-Lg. Histological study was used to assess gut inflammation. Serum levels of TNF-α and IL-6 were measured. Serum IgG and IgE anti-Beta-Lg were determined by ELISA. Results: Compared with sensitized mice, Beta-Lg challenge of intestinal epithelium of taurine-pre-treated mice in Ussing chamber did not influence the intensity of Isc, nor produce any changes in the G, reflecting a reduction in the secretory response and epithelial permeability. Histological and morphometric analysis showed that taurine reduced the intestinal damage and limited intestine retraction caused by Beta-Lg sensitization. No statistically significant difference in the serum levels of TNF-α or IL-6 was found after oral or intraperitoneal administration of taurine. Treatment with taurine significantly decreased the IgG (p < 0.001) and IgE anti Beta-Lg levels (p < 0.05). Conclusions: These results have for the first time provided evidence that pre-treatment with taurine appears to prevent intestinal damage induced by Beta-Lg

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Taurine administration prevents the intestine from the damage induced by beta-lactoglobulin sensitization in a murine model of food allergy.

BACKGROUND: Allergy to cow's milk proteins has often been associated with dysfunction of the intestinal mucosa caused by chronic inflammation in infants. This study evaluated the protective effect of taurine on intestinal damage induced by beta-lactoglobulin (ß-Lg) in Balb/c mice used as an animal model of allergy to cow's milk proteins. METHODS: Balb/c mice were treated with taurine administered orally by gavage (3mmol/kg/day) or intraperitoneally (100mg/kg/day) for two weeks, then sensitized intraperitoneally with ß-Lg. The electrophysiological parameters: active ion transport of chloride (Short-circuit current: Isc) and the passive ion permeability (Conductance: G) were measured ex vivo in Ussing chamber by intestine challenge with ß-Lg. Histological study was used to assess gut inflammation. Serum levels of TNF-α and IL-6 were measured. Serum IgG and IgE anti-ß-Lg were determined by ELISA. RESULTS: Compared with sensitized mice, ß-Lg challenge of intestinal epithelium of taurine-pre-treated mice in Ussing chamber did not influence the intensity of Isc, nor produce any changes in the G, reflecting a reduction in the secretory response and epithelial permeability. Histological and morphometric analysis showed that taurine reduced the intestinal damage and limited intestine retraction caused by ß-Lg sensitization. No statistically significant difference in the serum levels of TNF-α or IL-6 was found after oral or intraperitoneal administration of taurine. Treatment with taurine significantly decreased the IgG (p<0.001) and IgE anti ß-Lg levels (p<0.05). CONCLUSIONS: These results have for the first time provided evidence that pre-treatment with taurine appears to prevent intestinal damage induced by ß-Lg.

[Anti-obesogenic effect of apple cider vinegar in rats subjected to a high fat diet]. / Effet anti-obésogène du vinaigre de cidre de pomme chez le rat soumis à un régime hyperlipidique.

AIM OF THE STUDY: The search of new anti-obesogenic treatments based on medicinal plants without or with minimal side effects is a challenge. In this context, the present study was conducted to evaluate the anti-obesogenic effect of apple cider vinegar (ACV) in Wistar rats subjected to a high fat diet. MATERIALS AND METHODS: Eighteen male Wistar rats (140±5g) were divided into 3 three equal groups. A witness group submitted to standard laboratory diet and two groups subjected to a high fat diet (cafeteria diet); one receives a daily gavage of apple cider vinegar (7mL/kg/d) for 30 days. Throughout the experiment monitoring the nutritional assessment, anthropometric and biochemical parameters is achieved. RESULTS: In the RCV vs RC group, we observed a highly significant decrease (P<0.001) in body weight and food intake. On the other hand, the VCP decreases very significantly different anthropometric parameters: BMI (P<0.01), chest circumference and abdominal circumference (P<0.001), decreases serum glucose levels (26.83%) and improves the serum lipid profile by reducing plasma levels of total cholesterol (34.29%), TG (51.06%), LDL-c (59.15%), VLDL (50%) and the total lipid (45.15%), and increasing HDL-c (39.39%), thus offering protection against oatherogenic risk (61.62%). CONCLUSION: This preliminary study indicates that the metabolic disorders caused by high fat diet (cafeteria) are thwarted by taking apple cider vinegar which proves to have a satiating effect, antihyperlipidemic and hypoglycemic effects, and seems prevent the atherogenic risk.

Protective effect of Enterococcus faecalis DAPTO 512 on the intestinal tract and gut mucosa: milk allergy application.

The allergenicity of ß-lactoglobulin (ß-Lg) was studied by using Ussing chamber in a murine model of ß-Lg allergy supplemented with hydrolysates obtained after fermentation of milk for 48 h at 37 (°)C with Enterococcus faecalis DAPTO 512, isolated from cow milk and identified by 16S rDNA sequence analysis. Balb/c mice were sensitised intraperitoneally with ß-Lg. Three groups of mice were formed: group 1, composed of naive mice used as control received only NaCl; group 2, positive control composed of mice sensitised intraperitoneally with ß-Lg; group 3, formed by mice which were given hydrolysates of 48 h then sensitised with ß-Lg. After 48 h of fermentation ß-casein and ß-Lg were degraded by E. faecalis DAPTO 512. ß-Lg immunisation was associated with strong IgG and IgE production in case of positive controls and a significant increase in short current circuit (Isc) and high conductance (G) responses were observed. The control and the hydrolysate groups showed a significant decrease in the production of IgG and IgE anti ß-Lg compared to the positive control. The allergenic potential of ß-Lg was markedly reduced in the group that received hydrolysates (Isc and G remained unchanged after intestine challenge with ß-Lg). The histological scrutiny showed villi atrophy, lymphocyte hyperplasia and a significant chorion detachment in the positive control group. In the group administered with hydrolysates of fermented milk, inflammatory signs were lower, the villi were long and thin and lymphocytes were less dense. The results showed that feeding of milk fermented with E. faecalis DAPTO 512 during 18 days prior to ß-Lg allergy induction exerts a protecting effect on the murine intestine and induces a significant decrease in the ß-Lg allergenicity.

Impact of gamma-radiation on antigenic properties of cow's milk beta-lactoglobulin.

This study evaluated the effects of gamma-radiation on the antigenic properties of beta-lactoglobulin in cow's milk. Liquid and lyophilized samples of cow's milk and whey were irradiated with gamma-cells (60Co) at dose levels of 3, 5, and 10 kGy, at room temperature in the presence of air. Effects of treatment on proteins were monitored by Lowry's method, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and enzyme-linked immunosorbent assay. Radiation did not affect the molecular-weight distributions of proteins, but it did reduce their solubility. Furthermore, results showed that irradiation at 10 kGy increased the recognition of milk and whey powders by anti-beta-lactoglobulin (beta-Lg) rabbit immunoglobulin G, with the other samples remaining antigenically stable. These results indicate that gamma-rays do not reduce cow's milk beta-lactoglobulin antigenicity.

Jejunal response to beta-lactoglobulin in infants with cow's milk allergy.

Weaning is a transient period of life during which maternal proteins are replaced by foreign proteins. Concomitantly, in early postnatal life, both digestive and immune systems undergo a maturation process. Allergy to cow's milk protein may develop in human infants during weaning, determining digestive, respiratory, cutaneous or systemic symptoms. We studied the intestinal response to bovine milk beta-lactoglobulin (beta-LG) in infants with cow's milk allergy, first during the active phase, and then during the symptom-free stage. During the active phase, transepithelial transport of the beta-LG across the intestinal epithelial layer stimulated the sensitized subepithelial immune cells. This stimulation induced a rise in short-circuit current suggestive of an electrogenic chloride secretion and impaired protein handling by the epithelium. These findings underline the dual role of the epithelial layer in intestinal function: on one hand, it takes an active part in allowing dietary antigens to stimulate the submucosal system, and on the other hand becomes the target for mediators involved in food allergy.

Transport of beta-lactoglobulin across rabbit ileum in vitro.

Intestinal transepithelial transport constitutes a major limiting step in the transfer of food protein antigens to the blood. This transport was studied in isolated rabbit ileum in Ussing chamber in vitro for the milk protein antigen beta-lactoglobulin (beta-Lg). The transepithelial passage of beta-Lg was measured by enzyme-linked immunosorbent assay (ELISA) and radiolabeled protein transfer and compared with that of the nonmetabolizable marker polyethylene glycol (PEG)-4000. When 1 mg/ml of beta-[14C]Lg or [3H]PEG was added to the mucosal side of the tissue, the total uptake, measured as the transfer of radiolabeled material across the ileum, was significantly higher for beta-Lg than for PEG (5.46 +/- 1.75 vs. 1.43 +/- 0.26 micrograms.h-1.cm-2). Measured by ELISA, 6-9% of the total amount of beta-Lg transported was absorbed in an intact antigenic form. This transport of intact beta-Lg was inhibited by the metabolic inhibitors 50 mM 2-deoxyglucose and 1 mM azide added simultaneously, was reduced by the microtubule assembly inhibitor 0.05 mM colchicine, and was enhanced by 20 mM ammonia, which inhibits lysosomal proteolytic activity. These results indicate that beta-Lg is efficiently absorbed by the intestinal mucosa of adult animals, partly in intact antigenic form and that beta-Lg transport is probably transcellular, as observed for other proteins. The finding that beta-Lg is absorbed in intact antigenic form agrees with other reports implying that beta-Lg is the main factor responsible for milk protein immunoreactivity and intolerance.

Permeability of milk protein antigens across the intestinal epithelium in vitro.

Degradations by proteolytic enzymes and intestinal epithelial permeability represent two major drawbacks to the transfer of food protein antigens to blood. These steps were studied in vitro for the milk protein antigens beta-lactoglobulin (beta-Lg), alpha-Lactalbumin (alpha-La) and beta-casein (beta-cas). Pepsin-trypsin hydrolysis and permeability in isolated rabbit ileum in Ussing chamber were suited by ELISA and radiolabelled-protein measurement. Pepsin-trypsin hydrolysis showed an increasing resistance in the order beta-cas less than alpha-La less than beta-Lg. The rate of absorption of the antigenic proteins by isolated rabbit ileum was in the same order, and the rate of absorption of the whole proteins (degraded and antigenic forms) was significantly higher for beta-Lg than for alpha-La and beta-cas. These results suggest a selective intestinal permeability for milk protein antigens. This selectivity is probably important in the mechanism of food protein sensitization via the oral route.

Behaviour of digestive enzymes in the pancreatic juice and pancreas of rats fed on a low-protein diet (3 p. 100 of cereal protein) then on a balanced diet (23.5 p. 100 of mixed protein).

The aim of this study in the rat was to determine the effect of a low-protein diet (3 p. 100 cereal protein) and balanced refeeding (23.5 p. 100 mixed protein) on the activity of some pancreatic digestive enzymes and the amount of their secretion. Parallel studies were carried out on the pancreas and its exocrine secretion. 1) With a low-protein diet (21 days), there was a decrease in the amounts of bile and pancreatic juice secreted. During balanced refeeding (18 days), the amount of bile secreted returned to normal and, although that of the juice increased, it was less than the amount secreted by the reference lot. 2) Body and pancreatic weights decreased slightly with the low-protein diet. The protein content and mitotic ability of the pancreas declined. However, during balanced refeeding, the ponderal weight of the pancreas returned to normal more rapidly than that of the overall organism. Pancreatic protein content and mitotic ability also augmented. 3) The low-protein diet produced an overall decrease in enzyme activity in the pancreas and in the juice. However, in the absence of any dietary stimulation, these activities were not affected proportionally in the same way as the pancreas and its exocrine secretion. Nevertheless, no disturbance in the digestion and absorption of the ration was observed. 4) During balanced refeeding, enzyme activities increased to different levels in the juice and the pancreas but after 18 days total enzyme activity had not been entirely recovered. 5) Enzyme activity varied widely, especially during the first 48 hrs of malnutrition and the first 36 hrs of refeeding.