Faecal SIgA secretion in infants fed on pre- or probiotic infant formula

Secretory immunoglobulin A (SIgA) plays an important role in the defence of the gastrointestinal tract. The level of faecal SIgA antibody is associated with increased neutralization and clearance of viruses. Formula-fed infants who lack the transfer of protective maternal SIgA from breast milk may benefit from strategies to support maturation of humoral immunity and endogenous production of SIgA. We aimed at studying the effects of standard, prebiotic and probiotic infant formulas on the faecal SIgA levels. At birth, infants of whom the mother had decided not to breastfeed were allocated to one of three formula groups in a randomized, double-blind fashion. Nineteen infants received standard infant formula; 19 received prebiotic formula containing a specific mixture of 0.6 g galacto-oligosaccharides (GOS)/fructo-oligosaccharides (FOS)/100 ml formula and 19 received probiotic formula containing 6.0 × 109 cfu Bifidobacterium animalis/100 ml formula. Faecal samples were taken on postnatal day 5, day 10, wk 4 and every 4 wk thereafter until wk 32. SIgA in faeces was determined by an enzyme-linked immunosorbent assay. During the intervention, infants fed on prebiotic formula showed a trend towards higher faecal SIgA levels compared with the standard formula-fed infants reaching statistical significance at the age of 16 wk. In contrast, infants fed on the probiotic formula showed a highly variable faecal SIgA concentration with no statistically significant differences compared with the standard formula group. Formula-fed infants may benefit from infant formulas containing a prebiotic mixture of GOS and FOS because of the observed clear tendency to increase faecal SIgA secretion. Adding viable B. animalis strain Bb-12 to infant formula did not reveal any sign for such a trend. Secretory immunoglobulin A (SIgA) is one of the most abundant immunoglobulin in the human body and is the predominant immunoglobulin in mucosal surfaces. SIgA plays a key role in the gastrointestinal defence mechanism against dietary and microbial antigens. It inhibits adherence and invasion of potentially harmful antigens into mucosal tissues and neutralizing toxins and virulence factors from microbial pathogens (1). It is well established that the level of faecal SIgA antibody correlates with higher virus-neutralizing capacity and increased viral clearance (2). IgA deficiency in humans is one of the most common immunodeficiencies and is associated with frequent gastrointestinal infections (3). There is accumulating evidence that the intestinal SIgA production is highly influenced by the intestinal microflora. Indeed, the development of the IgA-producing plasmablasts (intermediate stage of the development of a B-lymphocyte into IgA-producing plasma cell) in the intestinal mucosa seems to be affected by components of the intestinal microflora (4). During the first few weeks after birth, the mucosal humoral immunity is not in a mature state. Passive immunity in this phase is provided by breast milk, which contains high levels of SIgA and antimicrobial peptides. SIgA in breast milk are mainly directed against the mother's previous and current gut microflora (5). Breast milk SIgA protects the maternal mammary gland against mastitis, protects the neonatal mucosa against early exposure to microbes and limits bacterial translocation. In breast milk, SIgA levels are highest during the first days after birth (human colostrum contains 2¿5 mg SIgA/ml) and then gradually decrease to 0.5¿1 mg/ml (6). Although many factors may influence SIgA survival in the large intestine, measuring SIgA levels in faeces gives a good representation of the amount available in the colon (7). In the first 2¿4 wk of life, the concentration of IgA in faeces of breast-fed infants is substantially higher compared to that found in formula-fed infants in whom SIgA is basically undetectable (8). Between 4 wk and 6 months of life, faecal IgA concentrations in both breast-fed and formula-fed infants converge towards similar levels. At age 1¿2 yr, when weaning is completed, the production of SIgA reaches adult levels (9). It is generally recognized that intestinal microflora may play an active role in the ontogeny of the newborn's immune response. Studies performed in germ-free animals showed that colonization leads to the development of the gut-associated lymphoid tissue, including SIgA secretion in the intestine (10, 11). Moreau and Baforiau-Routhiau have shown that in particular bifidobacteria in the infant's intestine are important for the synthesis of IgA against viral enteropathogens. Therefore, they suggested that foods promoting bifidobacteria in the intestine could be instrumental in stimulating endogenous SIgA production and hence promote resistance in infants (12). Although the mechanism of immune stimulation by bifidobacteria is largely unknown, it is thought that the cell walls of Gram-positive bacteria, which are rich in peptidoglycans, may play a role. Both prebiotics and probiotics change the intestinal microflora by increasing the numbers of bifidobacteria and lactobacilli. Bifidobacteria and lactobacilli have various beneficial effects in health and disease, including maintenance of intestinal barrier integrity and mucoprotection, stimulation of protective immune responses and protection against harmful pathogens. During the last decade, interest on the immune effects of probiotics has increased markedly. Experimental studies showed that probiotics have strain-specific effects on immunity, for instance in the prevention or treatment of allergic disease. The reported effects of probiotics include enhancement of gut barrier function and induction of regulatory and pro-inflammatory immune responses (13). Additionally, several studies reported that supplementation of food with prebiotics or probiotics can increase SIgA response to viruses and bacteria. However, most of these studies were performed in animals or in vitro and the mechanisms for this immune stimulation are largely unknown (14¿18). As infants not receiving breast milk have lower SIgA levels during the first months of life, they would potentially benefit from strategies to support maturation and production of mucosal SIgA. Therefore, we studied the effects of infant formula with added probiotics or prebiotics on the faecal SIgA levels in infants. We hypothesized that infants on probiotics or prebiotics will have higher levels of total faecal SIgA compared with infants fed on a standard, unsupplemented infant formul

A casein hydrolysate based formulation attenuates obesity and associated non-alcoholic fatty liver disease and atherosclerosis in LDLr-/-.Leiden mice

Background: Obesity frequently associates with the development of non-alcoholic fatty liver disease (NAFLD) and atherosclerosis. Chronic inflammation in white adipose tissue (WAT) seems to be an important driver of these manifestations. Objective: This study investigated a combination of an extensively hydrolyzed casein (eHC), docosahexaenoic acid (DHA), arachidonic acid (ARA), and Lactobacillus Rhamnosus GG (LGG) (together referred to as nutritional ingredients, NI) on the development of obesity, metabolic risk factors, WAT inflammation, NAFLD and atherosclerosis in high-fat diet-fed LDLr-/-.Leiden mice, a model that mimics disease development in humans. Methods: LDLr-/-.Leiden male mice (n = 15/group) received a high-fat diet (HFD, 45 Kcal%) for 21 weeks with or without the NI (23.7% eHC, 0.083% DHA, 0.166% ARA; all w/w and 1x109 CFU LGG gavage 3 times/week). HFD and HFD+NI diets were isocaloric. A low fat diet (LFD, 10 Kcal%) was used for reference. Body weight, food intake and metabolic risk factors were assessed over time. At week 21, tissues were analyzed for WAT inflammation (crown-like structures), NAFLD and atherosclerosis. Effects of the individual NI components were explored in a follow-up experiment (n = 7/group). Results: When compared to HFD control, treatment with the NI strongly reduced body weight to levels of the LFD group, and significantly lowered (P<0.01) plasma insulin, cholesterol, triglycerides, leptin and serum amyloid A (P<0.01). NI also reduced WAT mass and inflammation. Strikingly, NI treatment significantly reduced macrovesicular steatosis, lobular inflammation and liver collagen (P<0.05), and attenuated atherosclerosis development (P<0.01). Of the individual components, the effects of eHC were most pronounced but could not explain the entire effects of the NI formulation. Conclusions: A combination of eHC, ARA, DHA and LGG attenuates obesity and associated cardiometabolic diseases (NAFLD, atherosclerosis) in LDLr-/-.Leiden mice. The observed reduction of inflammation in adipose tissue and in the liver provides a rationale for these comprehensive health effects

Arachidonic acid/docosahexaenoic acid-supplemented diet in early life reduces body weight gain, plasma lipids, and adiposity in later life in ApoE*3 Leiden mice

Scope: This study addresses whether early life arachidonic acid (ARA)/docosahexaenoic acid (DHA) supplementation or eicosapentaenoic acid (EPA)/DHA (Omacor) supplementation affects body weight gain, lipid metabolism, and adipose tissue quantity and quality in later life in ApoE*3Leiden-transgenic mice, a humanized model for hyperlipidemia and mild obesity. Methods and results: Four-week-old male ApoE*3Leiden mice were fed chow diet with or without a mixture of ARA (0.129 wt%) and DHA (0.088 wt%) or Omacor (0.30 wt% EPA, 0.25 wt% DHA). At age 12 weeks, mice were fed high-fat/high-carbohydrate (HFHC) diet without above supplements until age 20 weeks. Control mice received chow diet throughout the study. Mice receiving ARA/DHA gained less body weight compared to control and this effect was sustained when fed HFHC. Omacor had no significant effect on body weight gain. Plasma cholesterol and triglycerides were significantly lowered by both supplementations. At 20 weeks, epididymal fat mass was less in ARA/DHA-supplemented mice, while Omacor had no significant effect on fat mass. Both ARA/DHA and Omacor reduced inguinal adipocyte cell size; only ARA/DHA significantly reduced epididymal macrophage infiltration. Conclusion: This study shows that early life ARA/DHA, but not Omacor supplementation improves body weight gain later in life. ARA/DHA and to a lesser extentOmacor both improved adipose tissue quality

Neonatal supplementation of processed supernatant from Lactobacillus rhamnosus GG improves allergic airway inflammation in mice later in life

Background: Oral supplementation with probiotic bacteria can protect against the development of allergic and inflammatory diseases. Objective: The aim of this study was to investigate potential immunomodulatory and allergy-protective effects of processed Lactobacillus rhamnosus GG (LGG)-derived supernatants early in life in neonatal mice. Methods: In vitro, RAW264.7 mouse macrophages were stimulated with viable LGG, LGG-derived supernatants, prepared from different growth phases, and different size fractions thereof, and pro- and anti-inflammatory cytokine production was analysed. Supernatant fractions were also treated with protease, DNAse or carbohydrate-digesting enzymes to define the nature of immunomodulatory components. In vivo, neonatal Balb/c mice were orally supplemented with differentially processed LGG supernatants. Starting at 4 weeks of age, a protocol of ovalbumin-induced acute allergic airway inflammation was applied and protective effects of processed LGG supernatants were assessed. Results: Incubation of RAW264.7 cells with LGG-derived supernatants significantly increased TNFα and IL-10 production. These effects were not restricted to a particular molecular size fraction. Treatment with protease, but not with DNAse or carbohydrate-digesting enzymes, completely abolished the immunomodulatory activities. Incubation of TLR/NOD-transfected cells with LGG-derived supernatants revealed that recognition and signalling of bioactive components is mediated by TLR2 and NOD2. In vivo supplementation of newborn mice with processed LGG-derived supernatants resulted in pronounced protective effects on the allergic inflammatory response as reflected by reduced eosinophil numbers, modified T helper cell cytokine production, significantly less lung inflammation and reduced goblet cell numbers in comparison with sham-treated controls. Conclusion: LGG-derived supernatants exert immunomodulatory activities, and neonatal administration of specifically processed supernatants may provide an alternative to viable probiotics in reducing allergic inflammatory responses. © 2012 Blackwell Publishing Ltd

Early intake of long-chain polyunsaturated fatty acids preserves brain structure and function in diet-induced obesity

Vascular Surger

Infant milk formulas differ regarding their allergenic activity and induction of T-cell and cytokine responses

Background: Several hydrolyzed cow&apos;s milk (CM) formulas are available for avoidance of allergic reactions in CM-allergic children and for prevention of allergy development in high-risk infants. Our aim was to compare CM formulas regarding the presence of immunoreactive CM components, IgE reactivity, allergenic activity, ability to induce T-cell proliferation, and cytokine secretion. Methods: A blinded analysis of eight CM formulas, one nonhydrolyzed, two partially hydrolyzed (PH), four extensively hydrolyzed (EH), and one amino acid formula, using biochemical techniques and specific antibody probes was conducted. IgE reactivity and allergenic activity of the formulas were tested with sera from CM-allergic patients (n = 26) in RAST-based assays and with rat basophils transfected with the human FcεRI, respectively. The induction of T-cell proliferation and the secretion of cytokines in Peripheral blood mononuclear cell (PBMC) culture from CM allergic patients and nonallergic individuals were assessed. Results: Immune-reactive α-lactalbumin and β-lactoglobulin were found in the two PH formulas and casein components in one of the EH formulas. One PH formula and the EH formula containing casein components showed remaining IgE reactivity, whereas the other hydrolyzed formulas lacked IgE reactivity. Only two EH formulas and the amino acid formula did not induce T-cell proliferation and proinflammatory cytokine release. The remaining formulas varied regarding the induction of Th2, Th1, and proinflammatory cytokines. Conclusion: Our results show that certain CM formulas without allergenic and low proinflammatory properties can be identified and they may also explain different outcomes obtained in clinical studies using CM formulas. © 2016 The Authors. Allergy Published by John Wiley &amp; Sons Ltd

Visualization of clustered IgE epitopes on α-lactalbumin

Background: α-Lactalbumin (α-La) is a major cow&apos;s milk (CM) allergen responsible for allergic reactions in infants. Objective: We performed molecular, structural, and immunologic characterization of α-La. Methods: Recombinant α-lactalbumin (rα-La) was expressed in Escherichia coli, purified to homogeneity, and characterized by means of mass spectrometry and circular dichroism, and its allergenic activity was studied by using microarray technology, as well as in a basophil histamine release assay. IgE epitope mapping was performed with synthetic peptides. Results: According to circular dichroism analysis, rα-La represented a folded protein with a high thermal stability and refolding capacity. rα-La reacted with IgE antibodies from 57.6% of patients with CM allergy (n = 66) and induced the strongest basophil degranulation with sera from patients with CM allergy who had exhibited gastrointestinal symptoms or severe systemic reactions on CM exposure. rα-La contained sequential and conformational IgE epitopes. Superposition of IgE-reactive peptides onto the 3-dimensional structure of α-La revealed a close vicinity of the N- and C-terminal peptides within a surface-exposed patch. Conclusions: rα-La can be used for the diagnosis of patients with severe allergic reactions to CM and serves as a paradigmatic tool for the development of therapeutic strategies for CM allergy. © 2010 American Academy of Allergy, Asthma &amp; Immunology