Long-term exposure from perinatal life to food-grade TiO2 alters intestinal homeostasis and predisposes to food allergy in young mice.

BACKGROUND: Food allergy (FA) is an inappropriate immunological response to food proteins resulting from an impaired induction of oral tolerance. Various early environmental factors can affect the establishment of intestinal homeostasis, predisposing to FA in early life. In this context, we aimed to assess the effect of chronic perinatal exposure to food-grade titanium dioxide (fg-TiO2 ), a common food additive. METHODS: Dams were fed a control versus fg-TiO2 -enriched diet from preconception to weaning, and their progeny received the same diet at weaning. A comprehensive analysis of baseline intestinal and systemic homeostasis was performed in offspring 1 week after weaning by assessing gut barrier maturation and microbiota composition, and local and systemic immune system and metabolome. The effect of fg-TiO2 on the susceptibility of progeny to develop oral tolerance versus FA to cow's milk proteins (CMP) was performed starting at the same baseline time-point, using established models. Sensitization to CMP was investigated by measuring ß-lactoglobulin and casein-specific IgG1 and IgE antibodies, and elicitation of the allergic reaction by measuring mouse mast cell protease (mMCP1) in plasma collected after an oral food challenge. RESULTS: Perinatal exposure to fg-TiO2 at realistic human doses led to an increased propensity to develop FA and an impaired induction of oral tolerance only in young males, which could be related to global baseline alterations in intestinal barrier, gut microbiota composition, local and systemic immunity, and metabolism. CONCLUSIONS: Long-term perinatal exposure to fg-TiO2 alters intestinal homeostasis establishment and predisposes to food allergy, with a clear gender effect.

Route of Sensitization to Peanut Influences Immune Cell Recruitment at Various Mucosal Sites in Mouse: An Integrative Analysis.

Symptom occurrence at the first ingestion suggests that food allergy may result from earlier sensitization via non-oral routes. We aimed to characterize the cellular populations recruited at various mucosal and immune sites after experimental sensitization though different routes. BALB/cJ mice were exposed to a major allergenic food (peanut) mixed with cholera toxin via the intra-gastric (i.g.), respiratory, cutaneous, or intra-peritoneal (i.p.) route. We assessed sensitization and elicitation of the allergic reaction and frequencies of T cells, innate lymphoid cells (ILC), and inflammatory and dendritic cells (DC) in broncho-alveolar lavages (BAL), lungs, skin, intestine, and various lymph nodes. All cellular data were analyzed through non-supervised and supervised uni/multivariate analysis. All exposure routes, except cutaneous, induced sensitization, but intestinal allergy was induced only in i.g.- and i.p.-exposed mice. Multivariate analysis of all cellular constituents did not discriminate i.g. from control mice. Conversely, respiratory-sensitized mice constituted a distinct cluster, characterized by high local inflammation and immune cells recruitment. Those mice also evidenced changes in ILC frequencies at distant site (intestine). Despite absence of sensitization, cutaneous-exposed mice evidenced comparable changes, albeit less intense. Our study highlights that the initial route of sensitization to a food allergen influences the nature of the immune responses at various mucosal sites. Interconnections of mucosal immune systems may participate in the complexity of clinical manifestations as well as in the atopic march.

Prenatal air pollution exposure to diesel exhaust induces cardiometabolic disorders in adulthood in a sex-specific manner.

BACKGROUND: Results from observational and experimental studies indicate that exposure to air pollutants during gestation reduces birth weight, whereas little is known on potential cardiometabolic consequences for the offspring at adulthood. OBJECTIVES: Our aim was to evaluate the long-term effects of gestational exposure to diesel engine exhaust (DE) on adult offspring phenotype in a rabbit model. METHODS: The protocol was designed to mimic human exposure in large European cities. Females rabbits were exposed to diluted (1 mg/m3) DE (exposed, n = 9) or clean air (controls, n = 7), from 3 days after mating, 2 h/d and 5 d/wk in a nose-only inhalation system throughout gestation (gestation days 3-27). After birth and weaning, 72 offspring (47 exposed and 25 controls) were raised until adulthood (7.5 months) to evaluate their cardio-metabolic status, including the monitoring of body weight and food intake, fasting biochemistry, body composition (iDXA), cardiovascular parameters and glucose tolerance. After a metabolic challenge (high fat diet in males and gestation in females), animals were euthanized for postmortem phenotyping. RESULTS: Sex-specific responses to maternal exposure were observed in adult offspring. Age-related increases in blood pressure (p = 0.058), glycaemia (p = 0.029), and perirenal fat mass (p = 0.026) as well as reductions in HDL-cholesterol (p = 0.025) and fat-to-body weight ratio (p = 0.011) were observed in exposed males, suggesting a metabolic syndrome. Almost only trends were observed in exposed females with higher triglycerides and decreased bone density compared to control females. Metabolic challenges triggered or amplified some biological responses, especially in females. CONCLUSIONS: In utero exposure to air pollution predisposed rabbit offspring to cardiometabolic disorders in a sex-specific manner.

Sensitization Potency of Sunflower Seed Protein in a Mouse Model: Identification of 2S-Albumins More Allergenic Than SFA-8.

SCOPE: Food allergy to sunflower seed (SFS) protein is not frequent and only non-specific lipid transfert protein (nsLTP) Hel a 3 is officially recognized as a food allergen. Out of the eleven seed storage 2S-albumins (SESA) detected in SFS, only SFA-8 allergenicity has been investigated so far. The study aimed then to evaluate SFS protein allergenicity and particularly, to compare the sensitization potency of SESA in a mouse model. METHODS AND RESULTS: The most abundant SESA and nsLTP were isolated from SFS through a combination of chromatographic methods. Purified proteins were then used to measure specific IgG1 and IgE responses in BALB/c mice orally sensitized to different SFS protein isolates. The study, thus, confirmed the allergenicity of SFA-8 and Hel a 3 but mice were also highly sensitized to other SESA such as SESA2-1 or SESA20-2. Furthermore, competitive inhibition of IgE-binding revealed that SFA-8 IgE-reactivity was due to cross-reactivity with other SESA. 11S-globulins were weakly immunogenic and were rapidly degraded in an in vitro model of gastroduodenal digestion. In contrast, Hel a 3, SESA2-1 and SFA-8 were more resistant to proteolysis and gastroduodenal digestion did not affect their IgE-reactivity. CONCLUSIONS: SESA2-1 or SESA20-2 were more potent allergens than SFA-8 in this mouse model. Allergenicity of SESA must be now confirmed in SFS-allergic patients.

Administration of Extensive Hydrolysates From Caseins and Lactobacillus rhamnosus GG Probiotic Does Not Prevent Cow's Milk Proteins Allergy in a Mouse Model.

Background: Early nutrition may influence the development of food allergies later in life. In the absence of breastfeeding, hydrolysates from cow's milk proteins (CMP) were indicated as a prevention strategy in at risk infants, but their proof of effectiveness in clinical and pre-clinical studies is still insufficient. Thanks to a validated mouse model, we then assessed specific and nonspecific preventive effects of administration of extensive hydrolysates from caseins (eHC) on the development of food allergy to CMP. The additional nonspecific effect of the probiotic Lactobacillus GG (LGG), commonly used in infant formula, was also assessed. Methods: Groups of young BALB/cByJ female mice were pretreated by repeated gavage either with PBS (control mice), or with PBS solution containing non-hydrolyzed milk protein isolate (MPI), eHC or eHC+LGG (eq. of 10 mg of protein/gavage). All mice were then experimentally sensitized to CMP by gavage with whole CM mixed with the Th2 mucosal adjuvant Cholera toxin. All mice were further chronically exposed to cow's milk. A group of mice was kept naïve. Sensitization to both caseins and to the non-related whey protein ß-lactoglobulin (BLG) was evaluated by measuring specific antibodies in plasma and specific ex vivo Th2/Th1/Th17 cytokine secretion. Elicitation of the allergic reaction was assessed by measuring mMCP1 in plasma obtained after oral food challenge (OFC) with CMP. Th/Treg cell frequencies in gut-associated lymphoid tissue and spleen were analyzed by flow cytometry at the end of the protocol. Robust statistical procedure combining non-supervised and supervised multivariate analyses and univariate analyses, was conducted to reveal any effect of the pretreatments. Results: PBS pretreated mice were efficiently sensitized and demonstrated elicitation of allergic reaction after OFC, whereas mice pretreated with MPI were durably protected from allergy to CMP. eHC+/-LGG pretreatments had no protective effect on sensitization to casein (specific) or BLG (non-specific), nor on CMP-induced allergic reactions. Surprisingly, eHC+LGG mice demonstrated significantly enhanced humoral and cellular immune responses after sensitization with CMP. Only some subtle changes were evidenced by flow cytometry. Conclusion: Neither specific nor nonspecific preventive effects of administration of casein-derived peptides on the development of CMP food allergy were evidenced in our experimental setup. Further studies should be conducted to delineate the mechanisms involved in the immunostimulatory potential of LGG and to clarify its significance in clinical use.

Maternal exposure to diluted diesel engine exhaust alters placental function and induces intergenerational effects in rabbits.

BACKGROUND: Airborne pollution is a rising concern in urban areas. Epidemiological studies in humans and animal experiments using rodent models indicate that gestational exposure to airborne pollution, in particular diesel engine exhaust (DE), reduces birth weight, but effects depend on exposure duration, gestational window and nanoparticle (NP) concentration. Our aim was to evaluate the effects of gestational exposure to diluted DE on feto-placental development in a rabbit model. Pregnant females were exposed to diluted (1 mg/m(3)), filtered DE (NP diameter ≈ 69 nm) or clean air (controls) for 2 h/day, 5 days/week by nose-only exposure (total exposure: 20 days in a 31-day gestation). RESULTS: DE exposure induced early signs of growth retardation at mid gestation with decreased head length (p = 0.04) and umbilical pulse (p = 0.018). Near term, fetal head length (p = 0.029) and plasma insulin and IGF1 concentrations (p = 0.05 and p = 0.019) were reduced. Placental function was also affected, with reduced placental efficiency (fetal/placental weight) (p = 0.049), decreased placental blood flow (p = 0.009) and fetal vessel volume (p = 0.002). Non-aggregated and "fingerprint" NP were observed at various locations, in maternal blood space, in trophoblastic cells and in the fetal blood, demonstrating transplacental transfer. Adult female offspring were bred with control males. Although fetoplacental biometry was not affected near term, second generation fetal metabolism was modified by grand-dam exposure with decreased plasma cholesterol (p = 0.008) and increased triglyceride concentrations (p = 0.015). CONCLUSIONS: Repeated daily gestational exposure to DE at levels close to urban pollution can affect feto-placental development in the first and second generation.

Bimanual coordination with three hands: is the mirror hand of any help?

The mirror paradigm has been used extensively both as a research tool for studying kinesthesia in healthy individuals and as a therapeutic tool for improving recovery and/or alleviating symptoms in patients. The present study of healthy participants assessed the contribution of the mirror paradigm to motor control in a bimanual coordination task performed under sensorimotor disturbance conditions. In Experiment 1, the participants were required to produce symmetrical circles with both hands/arms at the same time. In Experiment 2, the task consisted of synchronous extension-flexion movements of both arms in the sagittal plane. These tasks were performed under four different visual conditions: (i) mirror vision (i.e. with the non-dominant arm reflected in a mirror--the third hand--and the dominant arm hidden), (ii) full vision (i.e. both arms visible), (iii) with only the non-dominant arm visible and (iv) with the eyes closed. In Experiments 1 and 2, sensorimotor disturbance was applied to the participant's dominant arm by co-vibrating antagonistic muscles (the biceps and the triceps). In the complex circle drawing task, bimanual performance was better in the mirror condition than when participants saw their non-dominant arm only. However, motor performance in the mirror vision condition was little better than in the eyes closed condition, regardless of whether or not sensorimotor disturbance was applied. In Experiment 2, there were no differences between the "eyes closed" and "mirror vision" conditions. Although mirror reflection of one arm has been shown to induce consistent, vivid, perceptual illusions (kinesthetic illusion), our results suggest that it is less effective in modulating motor behavior.

Effects of alpha-linolenic acid vs. docosahexaenoic acid supply on the distribution of fatty acids among the rat cardiac subcellular membranes after a short- or long-term dietary exposure.

BACKGROUND: Previous work showed that the functional cardiac effect of dietary alpha-linolenic acid (ALA) in rats requires a long feeding period (6 months), although a docosahexaenoic (DHA) acid-supply affects cardiac adrenergic response after 2 months. However, the total cardiac membrane n-3 polyunsaturated fatty acid (PUFA) composition remained unchanged after 2 months. This delay could be due to a specific reorganization of the different subcellular membrane PUFA profiles. This study was designed to investigate the evolution between 2 and 6 months of diet duration of the fatty acid profile in sarcolemmal (SL), mitochondrial (MI), nuclear (NU) and sarcoplasmic reticulum (SR) membrane fractions. METHODS: Male Wistar rats were randomly assigned to 3 dietary groups (n = 10/diet/period), either n-3 PUFA-free diet (CTL), or ALA or DHA-rich diets. After 2 or 6 months, the subcellular cardiac membrane fractions were separated by differential centrifugations and sucrose gradients. Each membrane profile was analysed by gas chromatography (GC) after lipid extraction. RESULTS: As expected the n-3 PUFA-rich diets incorporated n-3 PUFA instead of n-6 PUFA in all the subcellular fractions, which also exhibited individual specificities. The diet duration increased SFA and decreased PUFA in SL, whereas NU remained constant. The SR and MI enriched in n-3 PUFA exhibited a decreased DHA level with ageing in the DHA and CTL groups. Conversely, the n-3 PUFA level remained unchanged in the ALA group, due to a significant increase in docosapentaenoic acid (DPA). N-3 PUFA rich diets lead to a better PUFA profile in all the fractions and significantly prevent the profile modifications induced by ageing. CONCLUSION: With the ALA diet the n-3 PUFA content, particularly in SR and SL kept increasing between 2 and 6 months, which may partly account for the delay to achieve the modification of adrenergic response.