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Background & Aims: The health benefit of human milk (HM) for preterm infant development is known but the role of human milk oligosaccharides (HMOs) contained in HM remains underexplored. We explored the relationship between exposure to HMOs contained in mother's milk and growth and neurodevelopment at 2-years corrected age in preterm infants., Methods: Exclusively breastfed preterm infants born between 27 and 34 weeks of gestation were enrolled in a monocentric prospective observational study, LACTACOL. Samples of breast milk were collected once a week for 7 weeks after birth. HMOs and sialic acid were measured by liquid chromatography. Age and Stages questionnaire (ASQ) version 2 was used to assess 2-year neurodevelopmental outcome. We analyzed the relationship between HMO content and (i) infant neurodevelopment at 2-years, and (ii) growth outcome at discharge and at 2 years. A secondary analysis was performed among Secretor(+) Lewis(+) mothers. Only associations with a false discovery rate of 10% or less according to the Benjamini-Hochberg procedure were considered significant., Results: 137 preterm infants (mean gestational age of 31.3 ± 1.7 weeks, mean birth weight of 1494 g ± 336 g) born to 117 mothers (mean age of 30.8 ± 5.0 years) were enrolled. Total HMOs and most individual HMOs and sialic acid concentrations decreased with advancing postnatal age, except for lacto-N-fucopentaose-III and 3-fucosyllactose, which increased. Total HMOs were positively correlated with neonatal length growth (adjusted p = 0.012). Neither total HMOs nor any individual HMO correlated with ASQ score in the overall cohort. However, lacto-N-fucopentaose-III (LNFP-III) was significantly associated with total ASQ score (adjusted p ≤ 0.015) among the 104 infants born to Secretor(+) Lewis(+) mothers., Conclusions: In this exploratory study in very preterm infants, total HMOs and most individual HMOs, except LNFP-III, decreased with advancing postnatal age. Neither the concentration of total HMOs nor that of any individual HMO were associated with ASQ score at 2 years, except for LNFP-III in Secretor(+) Lewis(+) mothers., Competing Interests: Conflict of interest Rozé, Boquien, Darmaun, Simon, Moyon, Billard have no conflict of interest to declare., (Copyright © 2022 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Pain-related functional gastrointestinal disorders (FGIDs) are characterized by visceral hypersensitivity (VHS) associated with alterations in the microbiota-gut-brain axis. Since human milk oligosaccharides (HMOs) modulate microbiota, gut and brain, we investigated whether HMOs impact VHS, and explored the role of gut microbiota. To induce VHS, C57BL/6JRj mice received hourly water avoidance stress (WAS) sessions for 10 d, or antibiotics (ATB) for 12 d. Challenged and unchallenged (Sham) animals were fed AIN93M diet (Cont) or AIN93M containing 1% of a 6-HMO mix (HMO6). VHS was assessed by monitoring the visceromotor response to colorectal distension. Fecal microbiome was analyzed by shotgun metagenomics. The effect of HMO6 sub-blends on VHS and nociceptive pathways was further tested using the WAS model. In mice fed Cont, WAS and ATB increased the visceromotor response to distension. HMO6 decreased WAS-mediated electromyographic rise at most distension volumes and overall Area Under Curve (AUC=6.12±0.50 in WAS/HMO6 vs. 9.46±0.50 in WAS/Cont; P<.0001). In contrast, VHS in ATB animals was not improved by HMO6. In WAS, HMO6 promoted most microbiota taxa and several functional pathways associated with low VHS and decreased those associated with high VHS. Among the sub-blends, 2'FL+DFL and LNT+6'SL reduced visceromotor response close to Sham/Cont values and modulated serotoninergic and CGRPα-related pathways. This research further substantiates the capacity of HMOs to modulate the microbiota-gut-brain communication and identifies mitigation of abdominal pain as a new HMO benefit. Ultimately, our findings suggest the value of specific HMO blends to alleviate pain associated FGIDs such as infantile colic or Irritable Bowel Syndrome., (Copyright © 2021. Published by Elsevier Inc.)

Background: Excessive and inconsolable crying behavior in otherwise healthy infants (a condition called infant colic (IC)) is very distressing to parents, may lead to maternal depression, and in extreme cases, may result in shaken baby syndrome. Despite the high prevalence of this condition (20% of healthy infants), the underlying neural mechanisms of IC are still unknown., Methods: By employing the latest magnetic resonance imaging (MRI) techniques in newborns, we prospectively investigated whether newborns' early brain responses to a sensory stimulus (smell) is associated with a subsequent crying behavior., Results: In our sample population of 21 healthy breastfed newborns, those who developed IC at 6 weeks exhibited brain activation and functional connectivity in primary and secondary olfactory brain areas that were distinct from those in babies that did not develop IC. Different activation in brain regions known to be involved in sensory integration was also observed in colicky babies. These responses measured shortly after birth were highly correlated with the mean crying time at 6 weeks of age., Conclusions: Our results offer novel insights into IC pathophysiology by demonstrating that, shortly after birth, the central nervous system of babies developing IC has already greater reactivity to sensory stimuli than that of their noncolicky peers., Impact: Shortly after birth, the central nervous system of colicky infants has a greater sensitivity to olfactory stimuli than that of their noncolicky peers. This early sensitivity explains as much as 48% of their subsequent crying behavior at 6 weeks of life. Brain activation patterns to olfactory stimuli in colicky infants include not only primary olfactory areas but also brain regions involved in pain processing, emotional valence attribution, and self-regulation. This study links earlier findings in fields as diverse as gastroenterology and behavioral psychology and has the potential of helping healthcare professionals to define strategies to advise families.

Differences in vitamin and carotenoids content of human milk (HM) produced for infants born at term and preterm is poorly understood. In this study, HM was collected weekly for four and two months post-partum for preterm and term groups, respectively. Nutrients of interest, from single full breast expressions were measured by liquid chromatography coupled with mass spectrometry. Microbiological assay was employed for vitamin B 12 . When compared at equivalent post-partum age, vitamins B 1 , B 2 , B 6 , and B 9 were significantly higher in preterm than in term HM, but only during the first two weeks. No significant differences were observed for A, E, B 3 and B 12 between groups. Lycopene was the only carotenoid exhibiting a significant higher concentration in term than in preterm HM between weeks 1 and 4 post-partum. When compared at equivalent post-menstrual age, preterm milk was significantly higher for vitamins B 1 , B 2 , B 3 , B 6 and B 9 and lower levels of vitamins A, E, β-carotene, β-cryptoxanthin, lutein, zeaxanthin and lycopene compared to their term counterparts. These results suggest that preterm breastfed infants at term equivalent age may receive lower amounts of these micronutrients than breast-fed term neonates, possibly highlighting the need to supplement or fortify their nutritional intake with vitamins and carotenoids. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT #02052245., (Copyright © 2020 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Breastfeeding is integral in the proper maturation of the intestinal barrier and protection against inflammatory diseases. When human milk (HM) is not available, supplementation with HM bioactives like Human Milk Oligosaccharides (HMOs) may help in providing breastfeeding barrier-protective benefits. An increasing HMO variety is becoming industrially available, enabling approaching the HMO complexity in HM. We aimed at assessing the impact of blends of available HMOs on epithelial barrier function in vitro. The capacity of individual [2'-Fucosyllactose (2'FL), Difucosyllactose, Lacto-N-tetraose, Lacto-N-neotetraose, 3'-Siallylactose and 6'-Siallylactose] or varying combinations of 3, 5 and 6 HMOs to modulate fluorescein-isothiocyanate (FITC)-labelled Dextran 4 KDa (FD4) translocation and/or transepithelial resistance (TEER) was characterized in Caco-2: HT29- methotrexate (MTX) cell line monolayers before and after an inflammatory challenge with TNF-α and IFN-γ. The six HMO blend (HMO6) dose-dependently limited the cytokine-induced FD4 translocation and TEER decrease and increased TEER values before challenge. Similarly, 3 and 5 HMO blends conferred a significant protection against the challenge, with 2'FL, one of the most abundant but most variable oligosaccharides in HM, being a key contributor. Overall, our results suggest differential ability of specific HMOs in modulating the intestinal barrier and support the potential of supplementation with combinations of available HMOs to promote gut health and protect against intestinal inflammatory disorders.

An adequate mineral supply to preterm infants is essential for normal growth and development. This study aimed to compare the mineral contents of human milk (HM) from healthy mothers of preterm (28-32 weeks) and full term (>37 weeks) infants. Samples were collected weekly for eight weeks for the term group ( n = 34) and, biweekly up to 16 weeks for the preterm group ( n = 27). Iron, zinc, selenium, copper, iodine, calcium, magnesium, phosphorus, potassium, and sodium were quantitatively analyzed by Inductively Coupled Plasma-Mass Spectrometry. The mineral contents of both HM showed parallel compositional changes over the period of lactation, with occasional significant differences when compared at the same postpartum age. However, when the comparisons were performed at an equivalent postmenstrual age, preterm HM contained less zinc and copper from week 39 to 48 ( p < 0.002) and less selenium from week 39 to 44 ( p < 0.002) than term HM. This translates into ranges of differences (min-max) of 53% to 78%, 30% to 72%, and 11% to 33% lower for zinc, copper, and selenium, respectively. These data provide comprehensive information on the temporal changes of ten minerals in preterm HM and may help to increase the accuracy of the mineral fortification of milk for preterm consumption., Competing Interests: All authors, except L.B., J.-F.T., and C.J.F.F., are Nestlé employees.

Background: Proteins are major contributors to the beneficial effects of human milk (HM) on preterm infant health and development. Alpha-lactalbumin, lactoferrin, serum albumin and caseins represent approximately 85% of the total HM protein. The temporal changes of these proteins in preterm (PT) HM and its comparison with term (T) HM is poorly characterized., Aims: To quantify and compare the temporal changes of the major proteins in PT HM and T HM., Methods: HM was collected for 4 months postpartum at 12 time points for PT HM (gestational age 28 0/7-32 6/7 weeks; 280 samples) and for 2 months postpartum at 8 time points for T HM (gestational age 37 0/7-41 6/7 weeks; 220 samples). Proteins were measured with a micro-fluidic LabChip system., Results: Casein, alpha-lactalbumin and lactoferrin decreased with advancing stages of lactation in PT and T HM, whereas serum albumin remained stable. Only marginal differences between PT and T HM were observed for alpha-lactalbumin during postpartum weeks 3-5 and for serum albumin at the first week. However, a comparison of HM provided to preterm and term infants at the same postmenstrual ages revealed that alpha-lactalbumin contents were significantly lower in PT HM than in T HM during the 39-48 postmenstrual weeks., Conclusions: This study provides comprehensive information of the longitudinal changes of major proteins in PT and T HM, and suggests limited availability of alpha-lactalbumin, a nutritionally important protein, in breastfed PT infants after reaching the term corrected age. This information may be important to optimize HM protein fortification, although its biological relevance needs to be confirmed by intervention studies., Clinical Trial Registry: ClinicalTrials.gov (NCT02052245), https://clinicaltrials.gov/ct2/show/NCT02052245., (Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Background: Mother's own milk is the optimal source of nutrients and provides numerous health advantages for mothers and infants. As they have supplementary nutritional needs, very preterm infants may require fortification of human milk (HM). Addressing HM composition and variations is essential to optimize HM fortification strategies for these vulnerable infants., Aims: To analyze and compare macronutrient composition in HM of mothers lactating very preterm (PT) (28 0/7 to 32 6/7 weeks of gestational age, GA) and term (T) infants (37 0/7 to 41 6/7 weeks of GA) over time, both at similar postnatal and postmenstrual ages, and to investigate other potential factors of variations., Methods: Milk samples from 27 mothers of the PT infants and 34 mothers of the T infants were collected longitudinally at 12 points in time during four months for the PT HM and eight points in time during two months for the T HM. Macronutrient composition (proteins, fat, and lactose) and energy were measured using a mid-infrared milk analyzer, corrected by bicinchoninic acid (BCA) assay for total protein content., Results: Analysis of 500 HM samples revealed large inter- and intra-subject variations in both groups. Proteins decreased from birth to four months in the PT and the T HM without significant differences at any postnatal time point, while it was lower around term equivalent age in PT HM. Lactose content remained stable and comparable over time. The PT HM contained significantly more fat and tended to be more caloric in the first two weeks of lactation, while the T HM revealed higher fat and higher energy content later during lactation (three to eight weeks). In both groups, male gender was associated with more fat and energy content. The gender association was stronger in the PT group, and it remained significant after adjustments., Conclusion: Longitudinal measurements of macronutrients compositions of the PT and the T HM showed only small differences at similar postnatal stages in our population. However, numerous differences exist at similar postmenstrual ages. Male gender seems to be associated with a higher content in fat, especially in the PT HM. This study provides original information on macronutrient composition and variations of HM, which is important to consider for the optimization of nutrition and growth of PT infants., Competing Interests: C.L.G.-R., C.A.D.C., M.-C.C.-C., S.K.T., and M.A. are all employees of Nestec Ltd.; C.J.F.F., L.B. and J.-F.T. declare no conflict of interest.

Human milk oligosaccharides (HMOs) are a major component of human milk, and play an important role in protecting the infant from infections. Preterm infants are particularly vulnerable, but have improved outcomes if fed with human milk. This study aimed to determine if the HMO composition of preterm milk differed from that of term milk at equivalent stage of lactation and equivalent postmenstrual age. In all, 22 HMOs were analyzed in 500 samples of milk from 25 mothers breastfeeding very preterm infants (< 32 weeks of gestational age, < 1500g of birthweight) and 28 mothers breastfeeding term infants. The concentrations of most HMOs were comparable at equivalent postpartum age. However, HMOs containing α-1,2-linked fucose were reduced in concentration in preterm milk during the first month of lactation. The concentrations of a number of sialylated oligosaccharides were also different in preterm milk, in particular 3'-sialyllactose concentrations were elevated. At equivalent postmenstrual age, the concentrations of a number of HMOs were significantly different in preterm compared to term milk. The largest differences manifest around 40 weeks of postmenstrual age, when the milk of term infants contains the highest concentrations of HMOs. The observed differences warrant further investigation in view of their potential clinical impact., Competing Interests: S.A., C.A.D.C., N.S., A.B., M.A., and C.L.G.R. are all employees of Nestec Ltd. L.B., J.F.T. and C.J.F.F. declare no conflict of interest.

Gastrointestinal tolerance and fat and calcium (Ca) absorption are different between breast-fed (BF) and formula-fed (FF) infants. Certain components and/or structural particularities in human milk (HM), can contribute to favorable outcomes in BF infants. In HM, the long-chain saturated fatty acid (LCSFA) palmitic acid has a different stereospecific distribution (sn-2 position) compared to most infant formula (IF) (primarily sn-1, 3 positions), which may contribute to unfavorable outcomes. Evidence suggests palmitic acid is important in the formation of stool FA-mineral (or FA-Ca) soaps, associated with harder stools in FF infants. Partial replacement by structured palmitic acid-rich triacylglycerols (TAGs) promotes palmitic acid absorption. However, evidence for stool softening, improved fat absorption and reduced Ca excretion in stools is inconsistent. IFs with less palmitic acid can improve fat and Ca absorption, and stool consistency. The presence of other LCSFAs (myristic and stearic acids) in sn-1, 3 positions may also contribute to reduced absorption of fat and Ca, and stool hardness, in FF infants. Nevertheless, little attention has been given to modifying these other LCSFAs in IF. We review literature comparing the effect of HM and IF with different lipid compositions on stool patterns and/or fat and Ca absorption in healthy, term infants. Based on available data, we estimate a maximum level for sn-1, 3 LCSFAs of 13% of TAGs, under which fat and Ca absorption and stool consistency are improved. IF designed according to this threshold could efficiently improve nutrient absorption and stool patterns in healthy infants who cannot be breast-fed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: The pathophysiology of infantile colic is poorly understood, though various studies report gut microbiota dysbiosis in colicky infants. We aimed to test the hypothesis that colic-related dysbiosis is associated with visceral hypersensitivity triggered by an altered luminal milieu., Methods: Fecal samples from seven colicky and seven non-colicky infants were studied. Fecal supernatants (FS) were infused into the colons of C57/Bl6 mice (n=10/specimen). Visceral sensitivity was subsequently assessed in the animals by recording their abdominal muscle response to colorectal distension (CRD) by electromyography (EMG). Serine and cysteine protease activities were assessed in FS with specific substrates. Infant fecal microbiota composition was analyzed by DNA extraction and 16S rRNA gene pyrosequencing., Key Results: FS from colicky infants triggered higher EMG activity than FS from non-colicky infants in response to both the largest CRD volumes and overall, as assessed by the area under the curve of the EMG across all CRD volumes. Infant crying time strongly correlated with mouse EMG activity. Microbiota richness and phylogenetic diversity were increased in the colicky group, without showing prominent microbial composition alterations. Only Bacteroides vulgatus and Bilophila wadsworthia were increased in the colicky group. Bacteroides vulgatus abundance positively correlated with visceral sensitivity. No differences were found in protease activities., Conclusions & Inferences: Luminal contents from colicky infants trigger visceral hypersensitivity, which may explain the excessive crying behavior of these infants. Additional studies are required to determine the nature of the compounds involved, their mechanism of action, and the potential implications of intestinal microbiota in their generation., (© 2016 John Wiley & Sons Ltd.)

The gut barrier plays a crucial role by spatially compartmentalizing bacteria to the lumen through the production of secreted mucus and is fortified by the production of secretory IgA (sIgA) and antimicrobial peptides and proteins. With the exception of sIgA, expression of these protective barrier factors is largely controlled by innate immune recognition of microbial molecular ligands. Several specialized adaptations and checkpoints are operating in the mucosa to scale the immune response according to the threat and prevent overreaction to the trillions of symbionts inhabiting the human intestine. A healthy microbiota plays a key role influencing epithelial barrier functions through the production of short-chain fatty acids (SCFAs) and interactions with innate pattern recognition receptors in the mucosa, driving the steady-state expression of mucus and antimicrobial factors. However, perturbation of gut barrier homeostasis can lead to increased inflammatory signaling, increased epithelial permeability, and dysbiosis of the microbiota, which are recognized to play a role in the pathophysiology of a variety of gastrointestinal disorders. Additionally, gut-brain signaling may be affected by prolonged mucosal immune activation, leading to increased afferent sensory signaling and abdominal symptoms. In turn, neuronal mechanisms can affect the intestinal barrier partly by activation of the hypothalamus-pituitary-adrenal axis and both mast cell-dependent and mast cell-independent mechanisms. The modulation of gut barrier function through nutritional interventions, including strategies to manipulate the microbiota, is considered a relevant target for novel therapeutic and preventive treatments against a range of diseases. Several biomarkers have been used to measure gut permeability and loss of barrier integrity in intestinal diseases, but there remains a need to explore their use in assessing the effect of nutritional factors on gut barrier function. Future studies should aim to establish normal ranges of available biomarkers and their predictive value for gut health in human cohorts., (Copyright © 2017 the American Physiological Society.)

Adequate nutrition is important for neurodevelopmental outcomes in preterm-born infants. In this review, we aim to summarize the current knowledge on nutritional interventions initiated during the hospital stay targeting brain and cognitive development benefits in preterm human infants. Studies can broadly be split in general dietary intervention studies and studies investigating specific nutrients or nutritional supplements. In general, mother's breast milk was reported to be better for preterm infants' neurodevelopment compared to infant formula. The differences in methodologies make it difficult to conclude any effects of interventions with individual nutrients. Only protein and iron level studies showed some consistent findings regarding optimal doses; however, confirmatory studies are needed. This review does not support some widely accepted associations, such as that between long-chain polyunsaturated fatty acid supplementation and visual development. Clear nutritional recommendations cannot be made based on this review. However, the type of infant nutrition (i.e., breast milk versus formula or donor milk), the timing of the nutritional intervention, and the dose of the nutrient/supplement have been found to be relevant factors in determining the success of nutritional intervention studies in preterm infants.

Objectives: Microbiota modulation by probiotics in infants born by cesarean (C)-section is poorly understood. We aimed at assessing the response of C-section-delivered infant microbiota to a formula containing Lactobacillus reuteri Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSM) 17938 and comparing it with that of vaginally delivered infants., Methods: Infants delivered by C-section (C) and vaginally (V) were randomized to receive either control formula (CCt, n = 10; VCt, n = 10) or the same formula containing L reuteri (CLr, n = 11; VLr, n = 9) within 72 hours following birth. Stool samples were collected at 2 weeks and 4 months of age. Microbial DNA was extracted, amplified, and pyrosequenced., Results: The phylogenetic profiles of the CLr, VCt, and VLr microbiota were not significantly different at any age but diverged from that of CCt at 2 weeks. Compared with VCt, CCt displayed lower Bifidobacterium and higher Enterobacter, unclassified Enterobacteriaceae, Enterococcus, Clostridium, and unclassified Clostridiaceae relative abundance at 2 weeks, as well as lower Collinsella and higher Enterococcus and Coprococcus abundance at 4 months. The level of most of these taxa was not significantly different between the CLr and the vaginal-delivery groups. Compared with VCt, the only difference observed in VLr microbiota was higher Lactobacillus at the 2 study ages and Coprococcus at 4 months., Conclusions: Our results show that a formula containing L reuteri DSM 17938 does not essentially alter the microbiota in vaginally born infants. In C-section-delivered infants, however, this strain seems to play the role of keystone species by modulating the early development of the microbiota toward the composition found after vaginal delivery.

Human breast milk (BM) amino acid (AA) composition may be impacted by lactation stage or factors related to geographical location. The present cross-sectional study is aimed at assessing the temporal changes of BMAA over lactation stages in a large cohort of urban mothers in China. Four hundred fifty BM samples, collected in three Chinese cities covering eight months of lactation were analyzed for free (FAA) and total (TAA) AA by o-phthalaldehyde/ fluorenylmethylchloroformate (OPA/FMOC) derivatization. Concentrations and changes over lactation were aligned with previous reports. Both the sum and the individual TAA values significantly decreased during the first periods of lactation and then generally leveled off. Leucine and methionine were respectively the most and the least abundant indispensable amino acids across all the lactation stages, whereas glutamic acid + glutamine (Glx) was the most and cystine the least abundant dispensable AA. The contribution of FAA to TAA levels was less than 2%, except for free Glx, which was the most abundant FAA. In conclusion, the AA composition of the milk from our cohort of urban Chinese mothers was comparable to previous studies conducted in other parts of the world, suggesting that this is an evolutionary conserved trait largely independent of geographical, ethnic, or dietary factors., Competing Interests: Conflicts of InterestThis study was funded by Nestlé Nutrition Institute, China and Nestlé Research Centre, Beijing, China. C.L.G.R., M.A., L.G.K., G.V.P., and S.K.T. were all employees of Nestec Ltd. when this work was completed. Y.Z. and P.W. report grants from Nestle Research Center and Nestle Nutrition Institute China during the conduct of the study.

Human breast milk (BM) protein composition may be impacted by lactation stage or factors related to geographical location. The present study aimed at assessing the temporal changes of BM major proteins over lactation stages and the impact of mode of delivery on immune factors, in a large cohort of urban mothers in China. 450 BM samples, collected in three Chinese cities, covering 8 months of lactation were analyzed for α-lactalbumin, lactoferrin, serum albumin, total caseins, immunoglobulins (IgA, IgM and IgG) and transforming growth factor (TGF) β1 and β2 content by microfluidic chip- or ELISA-based quantitative methods. Concentrations and changes over lactation were aligned with previous reports. α-lactalbumin, lactoferrin, IgA, IgM and TGF-β1 contents followed similar variations characterized by highest concentrations in early lactation that rapidly decreased before remaining stable up to end of lactation. TGF-β2 content displayed same early dynamics before increasing again. Total caseins followed a different pattern, showing initial increase before decreasing back to starting values. Serum albumin and IgG levels appeared stable throughout lactation. In conclusion, BM content in major proteins of urban mothers in China was comparable with previous studies carried out in other parts of the world and C-section delivery had only very limited impact on BM immune factors.

The intestinal microbiota is a key determinant of gut homeostasis, which is achieved, in part, through regulation of antimicrobial peptide secretion. The aim of this study was to determine the efficiency by which members of the intestinal microbiota induce the antimicrobial peptide REGIII and to elucidate the underlying pathways. We showed that germfree mice have low levels of REGIII-γ in their ileum and colon compared to mice with different intestinal microbiota backgrounds. Colonization with a microbiota of low diversity (altered Schaedler flora) did not induce the expression of REGIII-γ as effectively as a complex community (specific pathogen free). Monocolonization with the probiotic Bifidobacterium breve, but not with the nonprobiotic commensal Escherichia coli JM83, upregulated REGIII-γ expression. Induction of REGIII-γ by B. breve was abrogated in mice lacking MyD88 and Ticam1 signaling. Both live and heat-inactivated B. breve but not spent culture medium from B. breve induced the expression of REGIII-α, the human ortholog and homolog of REGIII-γ, in human colonic epithelial cells (Caco-2). Taken together, the results suggest that REGIII-γ expression in the intestine correlates with the richness of microbiota composition. Also, specific bacteria such as Bifidobacterium breve NCC2950 effectively induce REGIII production in the intestine via the MyD88-Ticam1 pathway. Treatment with this probiotic may enhance the mucosal barrier and protect the host from infection and inflammation.

Background: The intestinal microbiota regulates key host functions. It is unknown whether modulation of the microbiota can affect a genetically determined host phenotype. Polymorphisms in the Nucleotide oligomerization domain (Nod)-like receptor family confer genetic risk for inflammatory bowel disease (IBD). We investigated whether the intestinal microbiota and the probiotic strain Bifidobacterium breve NCC2950 affect intestinal barrier function and responses to intestinal injury in Nod1(-/-); Nod2(-/-) mice., Methods: Specific pathogen-free (SPF) Nod1(-/-); Nod2(-/-) mice and mice gnotobiotically derived with altered Schaedler flora (ASF) biota were used. SPF Nod1(+/-); Nod2(+/-) littermates (generated by crossing SPF Nod1(-/-); Nod2(-/-) and germ-free C57BL/6 mice) and ASF Nod1(+/-); Nod2(+/-) mice were used as controls. SPF mice were gavaged daily with 10(9) -CFU B. breve for 14 days before colitis induction. Denaturing gradient gel electrophoresis (DGGE) and real-time polymerase chain reaction (PCR) were used to assess microbiota composition. Intestinal permeability was assessed by in vitro and in vivo techniques. Expressions of epithelial apical junction proteins, mucin, and antimicrobial proteins were assessed by quantitative reverse-transcription PCR (qRT-PCR) and immunofluorescence. Responses to intestinal injury were investigated using an acute experimental model of colitis., Results: Under SPF conditions, Nod1(-/-); Nod2(-/-) mice had increased paracellular permeability, decreased E-cadherin, and lower colonic antimicrobial RegIII-γ expression compared to Nod1(+/-); Nod2(+/-) littermate controls. These changes were associated with increased susceptibility to colitis. ASF colonization or B. breve supplementation normalized RegIII-γ expression and decreased susceptibility to dextran sodium sulfate (DSS) colitis in Nod1(-/-); Nod2(-/-) mice., Conclusions: The intestinal microbiota influences colitis severity in Nod1(-/-); Nod2(-/-) mice. The results suggest that colonization strategies with defined commensals or exogenous specific probiotic therapy may prevent intestinal inflammation in a genetically predisposed host., (Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.)

In this study, we assessed the effect of administering the antibiotic amoxicillin to rat pups on the immune response to orally fed ovalbumin (OVA). We first established that amoxicillin administration durably altered the gut microbiota of these animals. In parallel, we observed that the induction of the specific humoral response to ovalbumin was impaired when it occurred during antibiotic administration to the rat pups. We also examined the consequences of those observations on further allergic reactions. Amoxicillin administration had no significant impact on subsequent sensitization to OVA, as nonexacerbated systemic allergic responses were induced in antibiotic-treated animals. However, increased rat mast cell protease II levels and higher mast cell numbers were detected in their small intestines, independently of the antigen administration. Globally, our data suggest that antibiotic administration early in life negatively affects the specific immune response to a luminal antigen when it is first introduced during antibiotic administration. The increased mast cell numbers and mediator concentrations in the intestinal mucosae of the antibiotic-treated animals may testify to the early stages of an altered immune system homeostasis.