Evaluation of the efficiency of hydrolyzed whey formula to prevent cow's milk allergy in the BALB/c mouse model.

BACKGROUND: Partially hydrolyzed milk formulas have been proposed for primary prevention in at-risk infants, but evidence of their efficiency and elucidation of the underlying mechanisms are still lacking. Thanks to a Th2-biased mouse model mimicking at-risk patients, we aimed to assess the potency of a partially hydrolyzed whey formula (pHWF) to induce oral tolerance thus preventing further cow's milk (CM) allergy. METHODS: BALB/c mice were gavaged with pHWF, standard milk formula (SF), or vehicle only (PBS+). All mice were then orally sensitized to CM using cholera toxin and further chronically exposed to CM. Humoral (IgE, IgG1, IgG2a) and cellular (Th2/Th1/Th17 cytokine secretion; frequency of CD4+GATA3+ and CD4+CD25+Foxp3+ T cells in the spleen) responses against ß-lactoglobulin (BLG) and whole caseins (CAS) were assessed, as well as a marker of elicitation of allergic reaction (mMCP-1) released after an oral challenge with CM. RESULTS: All markers of sensitization and of allergic reaction were evidenced in the PBS+ mice and were significantly enhanced upon chronic exposure. Gavage with SF totally and durably prevented sensitization and elicitation of the allergic reaction. Conversely, pre-treatment with pHWF only reduced BLG-specific sensitization (IgE, Th2 cytokines), with no significant effect on sensitization to caseins. However, pHWF pre-treatment significantly reduced mMCP-1 concentration in plasma after CM challenges. CD4+CD25+Foxp3+ Treg cell frequency could not be correlated with tolerance efficiency. CONCLUSION: Partially hydrolyzed whey formula only partially prevents the further development of CM allergy in this Th2-biased model. A hydrolysate from both whey and casein fractions may be more efficient.

Preventive effects of royal jelly against anaphylactic response in a murine model of cow's milk allergy.

CONTEXT: Royal jelly (RJ) has long been used to promote human health. OBJECTIVE: The current study investigated the preventive effects of RJ against the development of a systemic and intestinal immune response in mice allergic to cow's milk proteins. MATERIALS AND METHODS: Balb/c mice treated orally for seven days with RJ at doses of 0.5, 1 and 1.5 g/kg were sensitized intraperitoneally with ß-lactoglobulin (ß-Lg). Serum IgG and IgE anti-ß-Lg were determined by an enzyme-linked immunosorbent assay (ELISA). Plasma histamine levels, symptom scores and body temperature were determined after in vivo challenge to ß-Lg. Jejunums were used for assessment of local anaphylactic responses by an ex vivo study in Ussing chambers and morphologic changes by histological analysis. RESULTS: RJ significantly decreased serum IgG (31.15-43.78%) and IgE (64.28-66.6%) anti-ß-Lg and effectively reduced plasma histamine level (66.62-67.36%) (p < 0.001) at all the doses tested. Additionally, no clinical symptoms or body temperature drops were observed in RJ-pretreated mice. Interestingly, RJ significantly reduced (p < 0.001) intestinal dysfunction by abolishing the secretory response (70.73-72.23%) induced by sensitization and prevented length aberrations of jejunal villi by 44.32-59.01% (p < 0.001). DISCUSSION AND CONCLUSIONS: We speculate that using RJ may help prevent systemic and anaphylactic response in allergic mice. These effects may be related to its inhibitory effects on the degranulation of mast cells.

Effect of tartrazine on digestive enzymatic activities: in vivo and in vitro studies.

Tartrazine (E102) is a synthetic food coloring, which belongs to the class of mono azo dyes and is known to cause numerous health problems. The current research aimed to evaluate the effect of this food dye on the enzymatic activity of amylase, lipase and proteases after a subchronic ingestion in Swiss mice. Additionally, an in vitro digestion model was used to highlight the relationship between the probable toxicity of tartrazine and the nature of the food ingested. The results show that there were no adverse effects of tartrazine on the body weight gain, and on amylase or lipase activities. However, in the high dose of tartrazine (0.05%) group, a significant decrease in trypsin and chymotrypsin enzymatic activities were observed. Regarding the in vitro digestion model, our findings show that there were no changes in the trypsin and chymotrypsin enzymatic activities either using 7.5 or 75 mg of tartrazine mixed with rice, butter or milk. We conclude that excessive consumption of tartrazine appears to alter the enzymatic activity of proteases in vivo which may have deleterious consequences on digestion. Even thought the dose close to the acceptable daily intake does not affect those activities, a strict control of tartrazine dose in high-consumption foods especially among children is an indispensable task.

Evaluating the Probiotic Potential of Lactobacillus plantarum Strains from Algerian Infant Feces: Towards the Design of Probiotic Starter Cultures Tailored for Developing Countries.

Lactobacilli naturally present in the neonatal gut are believed to be beneficial for the human hosts and are investigated as potential probiotics. In this study, we aimed to characterize six Lactobacillus plantarum strains derived from the feces of a breast-fed infant, for the development of new probiotic cultures. Our attention was focused on L. plantarum in reason of the presence, within such species, of both pro-technological and probiotic strains, i.e., a combination of particular interest to design tailored probiotic starter cultures for developing countries. The bacterial isolates exhibiting lactobacilli-like phenotypic characteristics were identified as members of the L. plantarum group by 16S rRNA gene sequencing, and their diversity was evaluated by randomly amplified polymorphic DNA (RAPD) PCR patterns. The selected strains were screened for probiotic potential through in vitro tests. Firstly, bacterial survival was evaluated in an in vitro system simulating the human oro-gastrointestinal tract, using also milk as a carrier matrix. Besides, physiological traits such as antibiotic susceptibility, antimicrobial activity against selected enteric pathogens, and adhesion to abiotic surfaces and to gastric mucin were studied. Considering the resistance to simulated gastrointestinal digestion and the results from the biofilm and mucin adhesion tests, a strain-denominated L. plantarum LSC3 was selected for further evaluation of in vitro adhesion ability to intestinal mucosa and immunomodulatory activities. L. plantarum LSC3 was able to adhere efficiently to human enterocyte-like cells (Caco-2 cells), and decreased IL-8 transcription while increasing IL-10 mRNA level, as revealed by transcriptional analysis on LPS-stimulated human (THP-1) macrophages. Our results highlight that L. plantarum LSC3 fulfills major in vitro probiotic criteria as well as interesting immunostimulatory properties, and thus may be a promising candidate for further in vivo studies aiming at the development of novel probiotic starter cultures.

Sulfanilic acid increases intracellular free-calcium concentration, induces reactive oxygen species production and impairs trypsin secretion in pancreatic AR42J cells.

We studied the effects of the tartrazine-metabolite sulfanilic acid on the physiology of pancreatic AR42J cells. Sulfanilic acid (1 µM-1 mM) induced a slow and progressive increase in intracellular free-calcium concentration that reached a plateau. The effect of sulfanilic acid was not concentration-dependent. Stimulation of cells with thapsigargin (1 µM) after treatment with sulfanilic acid (1 mM) induced a smaller Ca2+ response compared with that obtained with thapsigargin alone. Sulfanilic acid induced a concentration-dependent production of reactive oxygen species; however, this effect was not Ca2+-dependent. Depolarization of mitochondrial membrane potential was observed at the concentration of 1 mM sulfanilic acid. In the presence of the compound a decrease in the GSH/GSSG ratio was observed. A decrease in the expression of superoxide dismutase 2 was noted. Finally, stimulation of cells with CCK-8 led to a concentration-dependent increase of trypsin secretion that was impaired by pretreatment of cells with sulfanilic acid. Preincubation of cells with the antioxidant melatonin (100 µM) reduced the effect of sulfanilic acid on trypsin secretion. We conclude that sulfanilic acid might induce oxidative stress, which could alter Ca2+ signaling and enzyme secretion in pancreatic AR42J cells. This creates a situation potentially leading to damage of the exocrine pancreas.

Parenteral immunization to beta-lactoglobulin modifies the intestinal structure and mucosal electrical parameters in rabbit.

Systemic and local immune responses and the intestinal structure were examined in parenterally beta-Lg-sensitized rabbits. Immunization led to high IgG titers against beta-Lg. In a Ussing chamber, a sensitized ileum had a higher short-circuit current (Isc) and potential difference (PD) than a control following in vitro beta-Lg challenge. Histological study indicated that presence of the sensitizing antigen affected and considerably modified the structure of the intestinal mucosa in sensitized rabbits when compared to controls. These alterations were revealed by active atrophy and marked infiltration of the lymphocytes. These findings indicate that antigen exposure results in morphological changes and abnormalities affecting the transport of water and electrolytes. This study provides a clearer understanding of the physiopathological mechanisms of allergy to cow's milk protein.