Hepatic Mitochondrial Dysfunction and Immune Response in a Murine Model of Peanut Allergy.

BACKGROUND: Evidence suggests a relevant role for liver and mitochondrial dysfunction in allergic disease. However, the role of hepatic mitochondrial function in food allergy is largely unknown. We aimed to investigate hepatic mitochondrial dysfunction in a murine model of peanut allergy. METHODS: Three-week-old C3H/HeOuJ mice were sensitized by the oral route with peanut-extract (PNT). We investigated: 1. the occurrence of effective sensitization to PNT by analysing acute allergic skin response, anaphylactic symptoms score, body temperature, serum mucosal mast cell protease-1 (mMCP-1) and anti-PNT immunoglobulin E (IgE) levels; 2. hepatic involvement by analysing interleukin (IL)-4, IL-5, IL-13, IL-10 and IFN-γ mRNA expression; 3. hepatic mitochondrial oxidation rates and efficiency by polarography, and hydrogen peroxide (H₂O₂) yield, aconitase and superoxide dysmutase activities by spectrophotometry. RESULTS: Sensitization to PNT was demonstrated by acute allergic skin response, anaphylactic symptoms score, body temperature decrease, serum mMCP-1 and anti-peanut IgE levels. Liver involvement was demonstrated by a significant increase of hepatic Th2 cytokines (IL-4, IL-5 and IL-13) mRNA expression. Mitochondrial dysfunction was demonstrated by lower state 3 respiration rate in the presence of succinate, decreased fatty acid oxidation in the presence of palmitoyl-carnitine, increased yield of ROS proven by the inactivation of aconitase enzyme and higher H₂O₂ mitochondrial release. CONCLUSIONS: We provide evidence of hepatic mitochondrial dysfunction in a murine model of peanut allergy. These data could open the way to the identification of new mitochondrial targets for innovative preventive and therapeutic strategies against food allergy

Bugs for atopy: the Lactobacillus rhamnosus GG strategy for food allergy prevention and treatment in children

Food allergy (FA) is a major health issue for children living in Western countries. At this time the only proven treatment for FA is elimination of offender antigen from the diet. It is becoming clear that the development of gut microbiota exerts a profound influence on immune system maturation and tolerance acquisition. Increasing evidence suggests that perturbations in gut microbiota composition of infants are implicated in the pathogenesis of FA. These findings have unveiled new strategies to prevent and treat FA using probiotics bacteria or bacterial substance to limit T-helper (Th)/Th2 bias, which changes during the disease course. Selected probiotics administered during infancy may have a role in the prevention and treatment of FA. Lactobacillus rhamnosus GG (LGG) is the most studied probiotic in this field. Administration of LGG in early life have a role in FA prevention. Preliminary evidence shows that LGG accelerates oral tolerance acquisition in cow's milk allergic infants. We are understanding the mechanisms elicited by LGG and metabolites in influencing food allergen sensitization. A deeper definition of these mechanisms is opening the way to new immunotherapeutics for children affected by FA that can efficiently limit the disease burden

Breast milk butyrate as protective factor against food allergy

Conflicting evidences suggest a role for breast milk as pro- tective factor against food allergy. The major short chain fatty acids, butyrate produced by gut microbiota exerts positive effect on immune system. We aimed to see whether butyrate concen- tration in human milk is able to prevent food allergy in an animal model of cow milk allergy. Mature breast milk butyrate concentration from 40 healthy women (aged 21–42 yrs) was assessed by gas chromatography. 4- Week-old female C3H/HeOuJ mice were sensitized by oral route with -lactoglobulin (BLG, 20 mg) plus cholera toxin (CT, 10 g) as an adjuvant in the presence or absence of butyrate. Acute aller- gic skin response,anaphylactic symptom score, body temperature, intestinal permeability, anti-BLG IgE, IL-4 and IL-10 production were assessed soon after oral challenge. Mean butyrate concen- tration in breast milk was 0.75 mM (SD ± 0.15). Based on this concentration a daily dose of 30 mg/kg body weight was calculated. The same butyrate concentration was able to significantly prevent acute allergic skin response, anaphylactic symptom score, body temperature decrease, intestinal permeability increase, anti-BLG IgE, IL-4 and IL-10 production in CMA animal model (p < .05). Our data suggest a pivotal role for butyrate as an effective human milk component in food allergy prevention

Diagnosing and Treating Food Allergy

t Food allergy (FA) is defined as an abnormal immunological reaction to food proteins. Over 90 % of FAs in childhood are caused by eight foods: cow’s milk, hen’s egg, soy, peanuts, tree nuts, wheat, fish and shellfish. The diagnostic work up for a child with suspected FA includes detailed medical history, physical examination, FA screening tests and response to elimination diet and to oral food challenge. Sometimes additional diagnostic tools to explore intestinal damage and function could be adopted. Currently, the only treatment for FA relies on strict elimination diets supervised by the nutritionist. Main new therapeutic strategies for FA include allergen-specific (oral, sublingual, epicutaneous, subcutaneous immunotherapy and heat treatment of food) and nonallergen-specific therapies (humanized monoclonal antibodies, anti-IgE and anti-IL5, probiotics). An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the child’s nutritional status and growt

Extensively hydrolyzed casein formula alone or with L. rhamnosus GG reduces β-lactoglobulin sensitization in mice

Background: Extensively hydrolyzed casein formula (EHCF) has been proposed for the prevention and is commonly used for the treatment of cow's milk allergy (CMA). The addition of the probiotic Lactobacillus rhamnosus GG (LGG) to EHCF may induce faster acquisition of tolerance to cow's milk. The mechanisms underlying this effect are largely unexplored. We investigated the effects of EHCF alone or in combination with LGG on β-lactoglobulin (BLG) sensitization in mice. Methods: Three-week-old C3H/HeOuJ mice were sensitized by oral administration of BLG using cholera toxin as adjuvant at weekly intervals for 5 weeks (sensitization period). Two experimental phases were conducted: (i) EHCF or EHCF+LGG given daily, starting 2 weeks before the sensitization period and then given daily for 5 weeks and (ii) EHCF or EHCF+LGG given daily for 4 weeks, starting 1 week after the sensitization period. Diet free of cow's milk protein was used as control. Acute allergic skin response, anaphylactic symptom score, body temperature, intestinal permeability, anti-BLG serum IgE, and interleukin (IL)-4, IL-5, IL-10, IL-13, IFN-γ mRNA expression were analyzed. Peptide fractions of EHCF were characterized by reversed-phase (RP)-HPLC, MALDI-TOF mass spectrometry, and nano-HPLC/ESI-MS/MS. Results: Extensively hydrolyzed casein formula administration before or after BLG-induced sensitization significantly reduced acute allergic skin reaction, anaphylactic symptom score, body temperature decrease, intestinal permeability increase, IL-4, IL-5, IL-13, and anti-BLG IgE production. EHCF increased expression of IFN-γ and IL-10. Many of these effects were significantly enhanced by LGG supplementation. The peptide panels were similar between the two study formulas and contained sequences that could have immunoregulatory activities. Conclusions: The data support dietary intervention with EHCF for CMA prevention and treatment through a favorable immunomodulatory action. The observed effects are significantly enhanced by LGG supplementation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Lt

Butyrate as bioactive human milk protective component against food allergy

Background: Food allergy (FA) is a growing health problem worldwide. Effective strategies are advocated to limit the disease burden. Human milk (HM) could be considered as a protective factor against FA, but its mechanisms remain unclear. Butyrate is a gut microbiota-derived metabolite able to exert several immunomodulatory functions. We aimed to define the butyrate concentration in HM, and to see whether the butyrate concentration detected in HM is able to modulate the mechanisms of immune tolerance. Methods: HM butyrate concentration from 109 healthy women was assessed by GS-MS. The effect of HM butyrate on tolerogenic mechanisms was assessed in in vivo and in vitro models. Results: The median butyrate concentration in mature HM was 0.75&nbsp;mM. This butyrate concentration was responsible for the maximum modulatory effects observed in all experimental models evaluated in this study. Data from mouse model show that in basal condition, butyrate up-regulated the expression of several biomarkers of gut barrier integrity, and of tolerogenic cytokines. Pretreatment with butyrate significantly reduced allergic response in three animal models of FA, with a stimulation of tolerogenic cytokines, inhibition of Th2 cytokines production and a modulation of oxidative stress. Data from human cell models show that butyrate stimulated human beta defensin-3, mucus components and tight junctions expression in human enterocytes, and IL-10, IFN-γ and FoxP3 expression through epigenetic mechanisms in PBMCs from FA children. Furthermore, it promoted the precursors of M2 macrophages, DCs and regulatory T cells. Conclusion: The study's findings suggest the importance of butyrate as a pivotal HM compound able to protect against FA

Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants.

Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow's milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. Our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut