Prenatal administration of Lactobacillus rhamnosus has no effect on the diversity of the early infant gut microbiota

The Role of Diet and Nutritional Interventions for the Infant Gut Microbiome

The infant gut microbiome plays a key role in the healthy development of the human organism and appears to be influenced by dietary practices through multiple pathways. First, maternal diet during pregnancy and infant nutrition significantly influence the infant gut microbiota. Moreover, breastfeeding fosters the proliferation of beneficial bacteria, while formula feeding increases microbial diversity. The timing of introducing solid foods also influences gut microbiota composition. In preterm infants the gut microbiota development is influenced by multiple factors, including the time since birth and the intake of breast milk, and interventions such as probiotics and prebiotics supplementation show promising results in reducing morbidity and mortality in this population. These findings underscore the need for future research to understand the long-term health impacts of these interventions and for further strategies to enrich the gut microbiome of formula-fed and preterm infants.

Multi-strain probiotics during pregnancy in women with obesity influence infant gut microbiome development: results from a randomized, double-blind placebo-controlled study

Probiotics have been described to influence host health and prevent the risk of obesity by gut microbiome (GM) modulation. In a randomized double-blinded placebo-controlled feasibility study, we investigated whether Vivomixx® multi-strain probiotics administered to 50 women with obesity during pregnancy altered the GM composition and perinatal health outcomes of their infants up to 9 months after birth. The mothers and infants were followed up with four visits after birth: at 3 d, and at 3, 6, and 9 months after delivery. The infants were monitored by anthropometric measurements, fecal sample analysis, and questionnaires regarding health and diet.The study setup after birth was feasible, and the women and infants were willing to participate in additional study visits and collection of fecal samples during the 9-month follow-up. In total, 47 newborns were included for microbiome analysis.Maternal prenatal Vivomixx® administration did not alter infant GM diversity nor differential abundance, and the probiotic strains were not vertically transferred. However, the infant GM exhibited a decreased prevalence of the obesity-associated genera, Collinsella, in the probiotic group and of the metabolic health-associated Akkermansia in the placebo group, indicating that indirect community-scale effects of Vivomixx® on the GM of the mothers could be transferred to the infant.Moreover, 3 d after birth, the GM of the infant was influenced by mode of delivery and antibiotics administered during birth. Vaginally delivered infants had increased diversity and relative abundance of the metabolic health-associated Bifidobacterium and Bacteroides while having a decreased relative abundance of Enterococcus compared with infants delivered by cesarean section. Maternal antibiotic administration during birth resulted in a decreased relative abundance of Bifidobacteriumin the GM of the infants. In conclusion, this study observed potential effects on obesity-associated infant GM after maternal probiotic supplementation.

Effects of maternal probiotic supplementation on breast milk microbiome and infant gut microbiome and health: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The early-life microbiome is formed during the perinatal period and is critical for infants' lifelong health. This is established by maternal-infant microbiome crosstalk, which is mediated by the breast milk microbiome. The milk microbiome is dependent on the maternal gut microbiome, suggesting that it could potentially be restored through oral probiotic supplements. Therefore, we conducted this systematic review and meta-analysis to summarize the effect of maternal probiotic supplements on breast milk and infant gut microbiome composition and on infant health.

DATA SOURCES

The PubMed, EMBASE, Web of Science, Scopus, CINAHL, and Science Direct databases were searched until December 15, 2022.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials following the population, intervention, comparison, and outcome (population: pregnant or lactating women; intervention: probiotics; control: placebo or follow-up; outcome: breast milk and infant gut microbiome composition and infant health) principles were included.

METHODS

Using a random effect model, the standard mean difference, risk difference, and risk ratio with 95% confidence interval were used to measure each outcome. All analyses were conducted using the intention-to-treat approach. Heterogeneity was evaluated using I2 statistics.

RESULTS

The final data set included 24 randomized controlled trials with a total of 2761 mothers and 1756 infants. The overall effect of probiotics on the beneficial bacteria detection rate in breast milk had a risk difference of 24% (95% confidence interval, 0.1-0.37; P<.001; I2=91.12%). The pooled mean beneficial and pathogenic bacteria abundance in breast milk had a standard mean difference of 1.22 log10 colony forming units/mL (95% confidence interval, 0.48-1.97; P<.001; I2=95.51%) and -1.05 log10 colony forming unites/mL (95% confidence interval, -1.99 to -0.12; P=.03; I2=96.79%), respectively. The overall abundance of beneficial bacteria in the infant gut had a standard mean difference of 0.89 log10 colony forming units/g (95% confidence interval, 0.22-1.56; P=.01; I2=95.01%). It also controlled infant weight gain (standard mean difference, -0.49 kg/equivalent age; 95% confidence interval, -0.82 to -0.17; P<.001; I2=0.00%) and decreased the occurrence of infantile colic (risk ratio, 0.30; 95% confidence interval, 0.16-0.57; P<.001; I2=0.00%).

CONCLUSION

Maternal probiotic supplements effectively orchestrate the breast milk and infant gut microbiome with a wide range of clinical benefits and safety. Lactobacillus, Bifidobacterium, Streptococcus thermophilus, and S. boulardii can be used as maternal supplements to promote infant health.

Probiotic supplementation during pregnancy alters gut microbial networks of pregnant women and infants

BACKGROUND

Probiotic supplementation has been popular and widespread, yet we still lack a comprehensive understanding of how probiotic supplementation during pregnancy affects the gut microbial networks of pregnant women and infants. In this study, we firstly used network analysis to compare the gut microbiota of pregnant women with and without probiotic supplementation, as well as their infants.

METHODS

Thirty-one pairs of healthy pregnant women and infants were recruited and randomly divided into the probiotic group (15 mother-infant pairs) and the control group (16 mother-infant pairs). Pregnant women in the probiotic group consumed combined probiotics from 32 weeks to delivery. Fecal samples were collected from pregnant women and infants at several time points. Gut microbiota was evaluated using 16S rRNA gene sequencing. Intestinal microbial network and topological properties were performed using the molecular ecological network analysis.

RESULTS

No significant difference was found between the probiotic and control groups on the microbial alpha and beta diversity. As the gestational age increased, the total links, average degree, average clustering coefficient, robustness, and the proportion of positive correlations were increased in pregnant women with probiotics administration. In contrast, these indices were decreased in infants in the probiotic group.

CONCLUSION

Probiotic supplement does not change the microbial diversity of pregnant women and infants, but significantly alters the intestinal microbial network structure and properties. Although pregnant women have more complicated and stable networks after probiotic administration, their infants have less stable networks.

Probiotics as Adjuvants in Vaccine Strategy: Is There More Room for Improvement?

Background. It has been recognized that microbiota plays a key role in shaping immune system maturation and activity. Since probiotic administration influences the microbiota composition and acts as a biological response modifier, the efficacy of an adjuvant for boosting vaccine-specific immunity is investigated. Methods. A review of the literature was performed, starting from the mechanisms to laboratory and clinical evidence. Results. The mechanisms, and in vitro and animal models provide biological plausibility for microbiota use. Probiotics have been investigated as adjuvants in farm conditions and as models to understand their potential in human vaccinations with promising results. In human studies, although probiotics were effective in ameliorating seroconversion to vaccines for influenza, rotavirus and other micro-organisms, the results for clinical use are still controversial, especially in particular settings, such as during the last trimester of pregnancy. Conclusion. Although this topic remains controversial, the use of probiotics as adjuvant factors in vaccination represents a strategic key for different applications. The available data are deeply influenced by heterogeneity among studies in terms of strains, timing and duration of administration, and patients. Although these do not allow us to draw definitive conclusions, probiotics as adjuvants in vaccination should be considered in future studies, especially in the elderly and in children, where vaccine effectiveness and duration of immunization really matter.

Impact of Maternal Nutritional Supplementation during Pregnancy and Lactation on the Infant Gut or Breastmilk Microbiota: A Systematic Review

Recent evidence indicates that maternal dietary intake, including dietary supplements, during pregnancy and lactation may alter the infant gut or breastmilk microbiota, with implications for health outcomes in both the mother and infant. To review the effects of maternal nutritional supplementation during pregnancy and lactation on the infant gut or breastmilk microbiota a systematic literature search was conducted. A total of 967 studies published until February 2020 were found, 31 were eligible and 29 randomized control trials were included in the qualitative synthesis. There were 23 studies that investigated the effects of probiotic supplementation, with the remaining studies investigating vitamin D, prebiotics or lipid-based nutrient supplements (LNS). The effects of maternal nutritional supplementation on the infant gut microbiota or breastmilk microbiota were examined in 21 and 12 studies, respectively. Maternal probiotic supplementation during pregnancy and lactation generally resulted in the probiotic colonization of the infant gut microbiota, and although most studies also reported alterations in the infant gut bacterial loads, there was limited evidence of effects on bacterial diversity. The data available show that maternal probiotic supplementation during pregnancy or lactation results in probiotic colonization of the breastmilk microbiota. There were no observed effects between probiotic supplementation and breastmilk bacterial counts of healthy women, however, administration of Lactobacillus probiotic to nursing women affected by mastitis was associated with significant reductions in breastmilk Staphylococcal loads. Maternal LNS supplementation during pregnancy and lactation increased bacterial diversity in the infant gut, whilst vitamin D and prebiotic supplementation did not alter either infant gut bacterial diversity or counts. Heterogeneity in study design precludes any firm conclusions on the effects of maternal nutritional supplementation during pregnancy and lactation on the infant gut or breastmilk microbiota, warranting further research.

Maternal exposures and the infant gut microbiome: a systematic review with meta-analysis

Early life, including the establishment of the intestinal microbiome, represents a critical window of growth and development. Postnatal factors affecting the microbiome, including mode of delivery, feeding type, and antibiotic exposure have been widely investigated, but questions remain regarding the influence of exposures in utero on infant gut microbiome assembly. This systematic review aimed to synthesize evidence on exposures before birth, which affect the early intestinal microbiome. Five databases were searched in August 2019 for studies exploring pre-pregnancy or pregnancy 'exposure' data in relation to the infant microbiome. Of 1,441 publications identified, 76 were included. Factors reported influencing microbiome composition and diversity included maternal antibiotic and probiotic uses, dietary intake, pre-pregnancy body mass index (BMI), gestational weight gain (GWG), diabetes, mood, and others. Eleven studies contributed to three meta-analyses quantifying associations between maternal intrapartum antibiotic exposure (IAP), BMI and GWG, and infant microbiome alpha diversity (Shannon Index). IAP, maternal overweight/obesity and excessive GWG were all associated with reduced diversity. Most studies were observational, few included early recruitment or longitudinal follow-up, and the timing, frequency, and methodologies related to stool sampling and analysis were variable. Standardization and collaboration are imperative to enhance understanding in this complex and rapidly evolving area.

Can a probiotic supplement in pregnancy result in transfer to the neonatal gut: A systematic review

INTRODUCTION

The establishment of the neonatal gut microbiome is a crucial step that may have lifelong health implications. We aimed to systematically review evidence on maternal probiotic supplementation during pregnancy and vertical transfer of the corresponding strain to the infant gut.

MATERIAL AND METHODS

Medline, CINAHL, Embase, Web of Science, and OVID were searched from inception to September 2018. Studies of maternal probiotic supplementation for a minimum duration of 2 weeks and analyses of neonatal stool samples were included. The primary outcome was presence of the specific probiotic strain in the infant stool. Electronic databases were searched for relevant studies and references were cross-checked. Risk of bias among included studies was assessed and data were extracted independently by two authors.

RESULTS

Three studies were included in the review. Only one study was identified involving prenatal maternal probiotic supplementation alone. Neonatal colonization with the maternally administered probiotic was not demonstrated but supplementation with the probiotic influenced levels of a bacterial strain other than that found in the probiotic product. The other two studies identified included both prenatal and postnatal supplementation of either mother or infant. All three studies reported employing strain-specific isolation methodology to isolate the supplemented bacterial strain in infant stool but none used whole metagenome shotgun sequencing.

CONCLUSIONS

Few studies investigating transfer of a specific probiotic bacterial strain from mother to infant were identified, showing inconclusive evidence of vertical transfer.

The distribution characteristics of intestinal microbiota in children with community-acquired pneumonia under five Years of age

Pneumonia is the leading cause of morbidity and mortality in children under five years of age worldwide. Over the past decades, studies have shown that the upper respiratory pathogens are closely related to the occurrence of pneumonia. However, the co-occurrence of gut microbiome dysbiosis may have clinical manifestation in the prognosis of childhood pneumonia. The aim of the present study is to investigate the differences in gut microbial communities between children's diagnosed community-acquired pneumonia (CAP) under five compared to healthy controls in Inner Mongolia. Fecal samples were collected from children with CAP and healthy controls (<5 years old) and the genomic microbiome 16S rRNA was amplified using the hypervariable V4 region and subjected to MiSeq Illumina sequencing, and then analyzed for microbiota composition and phenotype. Finally functional profiling was performed by KEGG pathways analyses. Our results revealed a gut microbiota dysbiosis in children with CAP. Distinct gut microbiome composition and structure were associated with childhood CAP between two age categories compared to healthy controls. In addition, the phylogenic phenotype's prediction was found to be significantly different between the groups. The prominent genera in age group of 0-3 were Bifidobacterium and Enterococcus. On the contrary, Escherichia-Shigella, Prevotella, Faecalibacterium and Enterobacter were remarkably decreased in most of the fecal samples from CAP patients in age group of 0-3 compared to the control. At the genus level, the CAP children in the age group of 4-5 showed an increase in the abundance of Escherichia/Shigella, Bifidobacterium, Streptococcus and Psychrobacter and, a decrease in the abundance of Faecalibacterium, Bacteroides, Lachnospiraceae and Ruminococcus compared with the matched healthy controls. Moreover, CAP children in both age groups exhibited distinct profiles in the KEGG functional analysis. Our data revealed that the gut microbiota differ between CAP patients and health children and certain gut microbial species are associated with CAP. Further research to identify specific microbial species which may contribute to the development CAP are merited. In addition, rectification of microbiota dysbiosis may provide supplemental benefits for treatment of the childhood CAP.

Pre- and probiotics for allergy prevention: time to revisit recommendations?

Reduced intensity and diversity of microbial exposure is considered a major factor driving abnormal postnatal immune maturation and increasing allergy prevalence, particularly in more affluent regions. Quantitatively, the largest important source of early immune-microbial interaction, the gut microbiota, is of particular interest in this context, with variations in composition and diversity in the first months of life associated with subsequent allergy development. Attempting to restore the health consequences of the 'dysbiotic drift' in modern society, interventions modulating gut microbiota for allergy prevention have been evaluated in several randomized placebo-controlled trials. In this review, we provide an overview of these trials and discuss recommendations from international expert bodies regarding prebiotic, probiotic and synbiotic interventions. Recent guidelines from the World Allergy Organization recommend the use of probiotics for the primary prevention of eczema in pregnant and breastfeeding mothers of infants at high risk for developing allergy and in high-risk infants. It is however stressed that these recommendations are conditional, based on very low-quality evidence and great heterogeneity between studies, which also impedes specific and practical advice to consumers on the most effective regimens. We discuss how the choice of probiotic strains, timing and duration of administration can critically influence the outcome due to different effects on immune modulation and gut microbiota composition. Furthermore, we propose strategies to potentially improve allergy-preventive effects and enable future evidence-based implementation.

Dietary primary prevention of allergic diseases in children: the Philippine guidelines

Allergic diseases, such as asthma, allergic rhinitis, eczema, and food allergy, are preventable diseases. Primary prevention strategies of allergic diseases have been in scrutiny. Effective prevention strategies maybe started prenatally, postnatally, during infancy, and even during childhood. These guidelines have been prepared by the Philippine Society of Allergy, Asthma and Immunology and the Philippine Society for Pediatric Gastroenterology, Hepatology and Nutrition. They aim to provide evidence-based recommendations for the dietary primary prevention of allergic diseases in children. The primary audience of these guidelines is all healthcare practitioners who manage patients with potential allergic conditions. These guidelines are based on an exhaustive review of evidences, mostly systematic reviews, randomized controlled trials, and cohort studies. However, there are still many gaps in the evidence of dietary primary prevention of allergic diseases.

Intervention strategies for cesarean section-induced alterations in the microbiota-gut-brain axis

Microbial colonization of the gastrointestinal tract is an essential process that modulates host physiology and immunity. Recently, researchers have begun to understand how and when these microorganisms colonize the gut and the early-life factors that impact their natural ecological establishment. The vertical transmission of maternal microbes to the offspring is a critical factor for host immune and metabolic development. Increasing evidence also points to a role in the wiring of the gut-brain axis. This process may be altered by various factors such as mode of delivery, gestational age at birth, the use of antibiotics in early life, infant feeding, and hygiene practices. In fact, these early exposures that impact the intestinal microbiota have been associated with the development of diseases such as obesity, type 1 diabetes, asthma, allergies, and even neurodevelopmental disorders. The present review summarizes the impact of cesarean birth on the gut microbiome and the health status of the developing infant and discusses possible preventative and restorative strategies to compensate for early-life microbial perturbations.

The influence of dietary immunomodulatory factors on development of food allergy in children

In the last few years many studies have been conducted on the role of dietary and environmental factors in the prevention of allergic diseases among children. Many studies have shown that the diet of pregnant women and children in their early postnatal life, rich in antioxidants, vitamin D, and fatty acids is beneficial as it reduces the risk of allergy in their future life. Moreover, there are many reports about the main role of gut microbiota and probiotics in the allergy prevention, what can indicate new ways of procedures in allergic diseases.

Can probiotics benefit children with autism spectrum disorders?

Children with autism are commonly affected by gastrointestinal problems such as abdominal pain, constipation and diarrhea. In recent years, there has been a growing interest in the use of probiotics in this population, as it hypothetically may help to improve bowel habits and the behavioral and social functioning of these individuals. The gut microbiome plays an important role in the pathophysiology of organic as well as functional gastrointestinal disorders. Microbial modification with the use of antibiotics, probiotics, and fecal transplantation have been effective in the treatment of conditions such as recurrent Clostridium difficile infection, pouchitis, and irritable bowel syndrome. The present review presents a number of reported clinical, immunological and microbiome-related changes seen in children with autism compared to normally developed children. It also discusses gut inflammation, permeability concerns, and absorption abnormalities that may contribute to these problems. Most importantly, it discusses evidence, from human and animal studies, of a potential role of probiotics in the treatment of gastrointestinal symptoms in children with autism.

Microbial transmission from mothers with obesity or diabetes to infants: an innovative opportunity to interrupt a vicious cycle

Maternal obesity and diabetes dramatically increase the long-term risk for obesity in the next generation, and pregnancy and lactation may be critical periods at which to aim primary prevention to break the obesity cycle. It is becoming increasingly clear that the gut microbiome in newborns and infants plays a significant role in gut health and therefore child development. Alteration of the early infant gut microbiome has been correlated with the development of childhood obesity and autoimmune conditions, including asthma, allergies and, more recently, type 1 diabetes. This is likely to be due to complex interactions between mode of delivery, antibiotic use, maternal diet, components of breastfeeding and a network of regulatory events involving both the innate and adaptive immune systems within the infant host. Each of these factors are critical for informing microbiome development and can affect immune signalling, toxin release and metabolic signals, including short-chain fatty acids and bile acids, that regulate appetite, metabolism and inflammation. In several randomised controlled trials, probiotics have been administered with the aim of targeting the microbiome during pregnancy to improve maternal and infant health but the findings have often been confounded by mode of delivery, antibiotic use, ethnicity, infant sex, maternal health and length of exposure. Understanding how nutritional exposure, including breast milk, affects the assembly and development of both maternal and infant microbial communities may help to identify targeted interventions during pregnancy and in infants born to mothers with obesity or diabetes to slow the transmission of obesity risk to the next generation. The aim of this review is to discuss influences on infant microbiota colonisation and the mechanism(s) underlying how alterations due to maternal obesity and diabetes may lead to increased risk of childhood obesity.

Probiotics for allergy prevention

Probiotics, given either as a supplement or in infant foods, have been evaluated in randomised controlled trials for allergy prevention. Here, the aim is to give an overview of the results from these primary prevention studies and to discuss current strategies. In most studies, single strains or a mixture of strains of lactic acid bacteria and bifidobacteria have been used--prenatally, postnatally or perinatally. Several meta-analyses have reported a moderate benefit of probiotics for eczema prevention, and the most consistent effect has been observed with a combined perinatal intervention in infants at high risk of allergic disease due to familial predisposition. In a recent meta-analysis, the use of multi-strain probiotics appeared to be most effective for eczema prevention. No preventive effect has been shown for other allergic manifestations. As long-term follow-up data on later onset allergic conditions (asthma and allergic rhinitis) are available only from a few of the initiated studies, reports from ongoing follow-up studies that are adequately powered to examine long-term outcomes are anticipated to provide more insight. Arguably, the differences in many aspects of study design and the use of different probiotic strains and combinations have made direct comparison difficult. To date, expert bodies do not generally recommend probiotics for allergy prevention, although the World Allergy Organization (WAO) in their recently developed guidelines suggests considering using probiotics in pregnant women, during breastfeeding and/or to the infant if at high risk of developing allergic disease (based on heredity). However, in concordance with other expert bodies, the WAO guideline panel stressed the low level of evidence and the need for adequately powered randomised controlled trials and a more standardised approach before clinical recommendations on specific strains, dosages and timing can be given.

Microbial influences on hormesis, oncogenesis, and therapy: A review of the literature

Utilization of environmental stimuli for growth is the main factor contributing to the evolution of prokaryotes and eukaryotes, independently and mutualistically. Epigenetics describes an organism's ability to vary expression of certain genes based on their environmental stimuli. The diverse degree of dose-dependent responses based on their variances in expressed genetic profiles makes it difficult to ascertain whether hormesis or oncogenesis has or is occurring. In the medical field this is shown where survival curves used in determining radiotherapeutic doses have substantial uncertainties, some as large as 50% (Barendsen, 1990). Many in-vitro radiobiological studies have been limited by not taking into consideration the innate presence of microbes in biological systems, which have either grown symbiotically or pathogenically. Present in-vitro studies neglect to take into consideration the varied responses that commensal and opportunistic pathogens will have when exposed to the same stimuli and how such responses could act as stimuli for their macro/microenvironment. As a result many theories such as radiation carcinogenesis explain microscopic events but fail to describe macroscopic events (Cohen, 1995). As such, this review shows how microorganisms have the ability to perturb risks of cancer and enhance hormesis after irradiation. It will also look at bacterial significance in the microenvironment of the tumor before and during treatment. In addition, bacterial systemic communication after irradiation and the host's immune responses to infection could explain many of the phenomena associated with bystander effects. Therefore, the present literature review considers the paradigms of hormesis and oncogenesis in order to find a rationale that ties them all together. This relationship was thus characterized to be the microbiome.

Does Maternal Perinatal Probiotic Supplementation Alter the Intestinal Microbiota of Mother and Child?

OBJECTIVES

Maternal probiotic supplementation has been shown to prevent the development of atopic dermatitis in the offspring. We aimed to investigate whether probiotics in pregnant and breast-feeding mothers altered the colonization pattern and the diversity of the mothers' and children's intestinal microbiota.

METHODS

In a randomized, double-blind trial, women received probiotic milk or placebo from 36 weeks of gestation up to 3 months postnatally while breast-feeding. The probiotic milk contained Lactobacillus rhamnosus GG, L acidophilus La-5, and Bifidobacterium animalis subsp. lactis Bb-12. Stool samples were collected from the mothers at 30 to 36 weeks of gestation and 3 months after birth, and from the child at age 10 days, 3 months, 1 year, and 2 years, and bacteria were analyzed by quantitative polymerase chain reaction. Additionally, stool samples from 3-month-old and 2-year-old children were characterized using 16S ribosomal RNA gene deep sequencing to estimate the bacterial classes and genera, and the α- and β-diversity.

RESULTS

Three months after birth, both the prevalence and the relative abundance of the administered probiotic bacteria were significantly increased among the mothers in the probiotic group compared with among those in the placebo group. Only the Lactobacillus rhamnosus GG bacteria colonized the children at 10 days and at 3 months of age. There were no significant differences in the abundance of the administered probiotic bacteria between the groups at 1 and 2 years of age. For the bacterial classes and genera, and α- and β-diversity, there were no significant differences between the groups.

CONCLUSIONS

Different probiotic bacteria seem to have different ability to transfer from the mother to the child. We found no evidence that the probiotics altered the microbial composition or α- and β-diversity of the children.

The infant microbiome development: mom matters

The infant microbiome plays an essential role in human health and its assembly is determined by maternal-offspring exchanges of microbiota. This process is affected by several practices, including Cesarean section (C-section), perinatal antibiotics, and formula feeding, that have been linked to increased risks of metabolic and immune diseases. Here we review recent knowledge about the impacts on infant microbiome assembly, discuss preventive and restorative strategies to ameliorate the effects of these impacts, and highlight where research is needed to advance this field and improve the health of future generations.

Lactobacilli and Bifidobacteria enhance mucosal B cell responses and differentially modulate systemic antibody responses to an oral human rotavirus vaccine in a neonatal gnotobiotic pig disease model

B cells play a key role in generation of protective immunity against rotavirus infection, a major cause of gastroenteritis in children. Current RV vaccines are less effective in developing countries compared to developed countries. Commensals/probiotics influence mucosal immunity, but the role of early gut colonizing bacteria in modulating intestinal B cell responses to RV vaccines is largely unknown. We co-colonized neonatal gnotobiotic pigs, the only animal model susceptible to HRV diarrhea, with 2 dominant bacterial species present in the gut of breastfed infants, Lactobacillus rhamnosus strain GG and Bifidobacterium animalis lactis Bb12 to evaluate their impact on B cell responses to an attenuated (Att) human rotavirus (HRV) Wa strain vaccine. Following HRV challenge, probiotic-colonized, AttHRV vaccinated piglets had significantly lower fecal scores and reduced HRV shedding titers compared to uncolonized, AttHRV vaccinated pigs. The reduction in HRV diarrhea was significantly correlated with higher intestinal IgA HRV antibody titers and intestinal HRV-specific IgA antibody secreting cell (ASC) numbers in probiotic-colonized, AttHRV vaccinated pigs compared to uncolonized, vaccinated pigs. The significantly higher small intestinal HRV IgA antibody responses coincided with higher IL-6, IL-10 and APRIL responses of ileal mononuclear cells (MNCs) and the immunomodulatory effects of probiotics genomic DNA on TGF-β and IL-10 responses. However, serum RV IgG antibody titers and total IgG titers were significantly lower in probiotic-colonized, AttHRV vaccinated pigs compared to uncolonized, vaccinated pigs, both pre- and post-challenge. In summary, LGG and Bb12 beneficially modulated intestinal B cell responses to HRV vaccine.

Towards a better understanding of Lactobacillus rhamnosus GG--host interactions

Lactobacillus rhamnosus GG (LGG) is one of the most widely used probiotic strains. Various health effects are well documented including the prevention and treatment of gastro-intestinal infections and diarrhea, and stimulation of immune responses that promote vaccination or even prevent certain allergic symptoms. However, not all intervention studies could show a clinical benefit and even for the same conditions, the results are not univocal. Clearly, the host phenotype governed by age, genetics and environmental factors such as the endogenous microbiota, plays a role in whether individuals are responders or non-responders. However, we believe that a detailed knowledge of the bacterial physiology and the LGG molecules that play a key role in its host-interaction capacity is crucial for a better understanding of its potential health benefits. Molecules that were yet identified as important factors governing host interactions include its adhesive pili or fimbriae, its lipoteichoic acid molecules, its major secreted proteins and its galactose-rich exopolysaccharides, as well as specific DNA motifs. Nevertheless, future studies are needed to correlate specific health effects to these molecular effectors in LGG, and also in other probiotic strains.

Excess body weight during pregnancy and offspring obesity: potential mechanisms

The rates of child and adult obesity have increased in most developed countries over the past several decades. The health consequences of obesity affect both physical and mental health, and the excess body weight can be linked to an elevated risk for developing type 2 diabetes, cardiovascular problems, and depression. Among the factors that can influence the development of obesity are higher infant weights and increased weight gain, which are associated with higher risk for excess body weight later in life. In turn, mother's excess body weight during and after pregnancy can be linked to the risk for offspring overweight and obesity through dietary habits, mode of delivery and feeding, breast milk composition, and through the influence on infant gut microbiota. This review considers current knowledge of these potential mechanisms that threaten to create an intergenerational cycle of obesity.

Probiotics and prebiotics in preventing food allergy and eczema

PURPOSE OF REVIEW

To describe the current literature on clinical trials of probiotics for eczema and food allergy prevention in view of recent new approaches and long-term follow-ups.

RECENT FINDINGS

Attempting allergy prevention by probiotic administration has been most successful when assessing atopic eczema, the most prevalent allergic disease at an early age. More than half of the published studies demonstrate a decrease in eczema prevalence until 2 years, whereas the remaining studies fail to show an effect. Effects have been most consistent with combined prenatal and direct postnatal supplementation of the infant and appear strain-specific, with Lactobacillus rhamnosus most often showing an effect. Prenatal-only and postnatal-only studies often fail to show effects. Recent long-time follow-ups have shown promising but not consistent results. A very recent follow-up of a large well conducted cohort shows that long-term effects of eczema prevention persists until age 4 and prevention of respiratory allergies might also be possible.

SUMMARY

Prevention of eczema with probiotics seem to work until age 2 years and extended effects until 4 years have been shown in high-risk for allergy cohorts. Effects are strain-specific, with L. rhamnosus showing the most consistent effects especially when combining pre and postnatal administration.

Regulation of Intestinal Immune Responses through TLR Activation: Implications for Pro- and Prebiotics

The intestinal mucosa is constantly facing a high load of antigens including bacterial antigens derived from the microbiota and food. Despite this, the immune cells present in the gastrointestinal tract do not initiate a pro-inflammatory immune response. Toll-like receptors (TLRs) are pattern recognition receptors expressed by various cells in the gastrointestinal tract, including intestinal epithelial cells (IEC) and resident immune cells in the lamina propria. Many diseases, including chronic intestinal inflammation (e.g., inflammatory bowel disease), irritable bowel syndrome (IBS), allergic gastroenteritis (e.g., eosinophilic gastroenteritis and allergic IBS), and infections are nowadays associated with a deregulated microbiota. The microbiota may directly interact with TLR. In addition, differences in intestinal TLR expression in health and disease may suggest that TLRs play an essential role in disease pathogenesis and may be novel targets for therapy. TLR signaling in the gut is involved in either maintaining intestinal homeostasis or the induction of an inflammatory response. This mini review provides an overview of the current knowledge regarding the contribution of intestinal epithelial TLR signaling in both tolerance induction or promoting intestinal inflammation, with a focus on food allergy. We will also highlight a potential role of the microbiota in regulating gut immune responses, especially through TLR activation.

Evidence of preventive effect of probiotics and prebiotics for infantile eczema

PURPOSE OF REVIEW

Infantile eczema, and in particular atopic dermatitis are, in many children, the first manifestation of their predisposition to an atopic disease. Among existing prevention strategies, supplementation with probiotics and prebiotics belong to the most promising beneficial interventions. Highlighting the most recent literature, we review here the most recent studies on probiotics and prebiotics and hypothesize on the most efficient intervention strategies.

RECENT FINDINGS

Various probiotics and prebiotics, either alone or in combinations, have been administered, in general, during the late phase of pregnancy and up to 6 months of age. In general, a combination of probiotics and prebiotics given from pregnancy until early infancy has a higher potential for protecting the infant from developing early manifestations of eczema than short administration of one specific microorganism.

SUMMARY

The effect of probiotics and prebiotic supplementations on early manifestations of atopy such as infantile eczema are conflicting. Nevertheless, prevention strategies should aim for an enhanced efficacy by addressing not only interventions on the microbiota, but by combining them to other interventions, for example, to those aiming at actively inducing antigen-specific tolerance.

Probiotic milk consumption in pregnancy and infancy and subsequent childhood allergic diseases

BACKGROUND

Whether probiotics, which can influence the microbiome, prevent infant eczema or allergic disease remains an open question. Most studies have focused on high-risk infants.

OBJECTIVES

We sought to assess whether consumption of probiotic milk products protects against atopic eczema, rhinoconjunctivitis, and asthma in early childhood in a large population-based pregnancy cohort (the Norwegian Mother and Child Cohort study).

METHODS

We examined associations between consumption of probiotic milk products in pregnancy and infancy with questionnaire-reported atopic eczema, rhinoconjunctivitis, and asthma in 40,614 children. Relative risks (RRs) were calculated by using general linear models adjusted for potential confounders.

RESULTS

Consumption of probiotic milk in pregnancy was associated with a slightly reduced relative risk (RR) of atopic eczema at 6 months (adjusted RR, 0.94; 95% CI, 0.89-0.99) and of rhinoconjunctivitis between 18 and 36 months (adjusted RR, 0.87; 95% CI, 0.78-0.98) compared with no consumption during pregnancy. Maternal history of allergic disease did not notably influence the associations. When both the mother (during pregnancy) and infant (after 6 months of age) had consumed probiotic milk, the adjusted RR of rhinoconjunctivitis was 0.80 (95% CI, 0.68-0.93) relative to no consumption by either. Probiotic milk consumption was not associated with asthma at 36 months.

CONCLUSIONS

In this population-based cohort consumption of probiotic milk products was related to a reduced incidence of atopic eczema and rhinoconjunctivitis, but no association was seen for incidence of asthma by 36 months of age.

Recent advances on diagnosis and management of childhood asthma and food allergies

The epidemic of childhood allergic disorders has been associated to the decline of infectious disease. However, exposure to many triggers (airborne viruses, tobacco smoke, pollution, indoor allergens, etc.) contribute to the disease. Breast feeding practices, nutrition, dietary and obesity also play a multifaceted role in shaping the observed worldwide trends of childhood allergies. Guidelines for treatment are available, but their implementation is suboptimal. Then developed countries are slowing learning integrating the development of suitable guidelines with implementation plans. Awareness, psychosocial and family factors strongly influence asthma and food allergy control. Moreover, monitoring tools are necessary to facilitate self-management. By taking into consideration these and many other pragmatic aspects, national public health programs to control the allergic epidemic have been successful in reducing its impact and trace the need for future research in the area.

Meta-analysis of probiotics and/or prebiotics for the prevention of eczema

OBJECTIVE

The efficacy of probiotics and/or prebiotics for preventing eczema in infants remains unclear. This meta-analysis evaluated published studies on pro/prebiotics for eczema prevention, investigating bacterial strain efficacy and changes to the allergy status of the children involved.

METHODS

Randomized, double-blind, placebo-controlled trials were analysed, irrespective of bacterial strains used in the pro/prebiotics. Studies of pregnant women, nursing mothers and infants receiving pro/prebiotics were included. All infant participants were assessed within 2 years of birth. Incidences of eczema and systemic sensitization were measured by weighted relative risk ratios (RRR).

RESULTS

The 14 studies on probiotics had a pooled RRR of 0.69 (95% confidence interval [CI]: 0.62, 0.78). Three studies on prebiotic consumption showed a RRR of 0.80 (95% CI: 0.54, 1.18). One study of mixed pro/prebiotic (synbiotic) strains found a RRR ratio of 0.81 (95% CI: 0.66, 0.99). No consistent sensitization changes were found. Only the combination of nonspore lactobacilli and bifidobacteria reduced the incidence of eczema.

CONCLUSION

This meta-analysis found that probiotics or synbiotics may reduce the incidence of eczema in infants aged <2 years. Systemic sensitization did not change following probiotic administration.

Probiotics and food allergy

The exact prevalence of food allergy in the general population is unknown, but almost 12% of pediatric population refers a suspicion of food allergy. IgE mediated reactions to food are actually the best-characterized types of allergy, and they might be particularly harmful especially in children. According to the "hygiene hypothesis" low or no exposure to exogenous antigens in early life may increase the risk of allergic diseases by both delaying the development of the immune tolerance and limiting the Th2/Th1 switch. The critical role of intestinal microbiota in the development of immune tolerance improved recently the interest on probiotics, prebiotics, antioxidants, polyunsaturated fatty acid, folate and vitamins, which seem to have positive effects on the immune functions.Probiotics consist in bacteria or yeast, able to re-colonize and restore microflora symbiosis in intestinal tract. One of the most important characteristics of probiotics is their safety for human health. Thanks to their ability to adhere to intestinal epithelial cells and to modulate and stabilize the composition of gut microflora, probiotics bacteria may play an important role in the regulation of intestinal and systemic immunity. They actually seem capable of restoring the intestinal microbic equilibrium and modulating the activation of immune cells.Several studies have been recently conducted on the role of probiotics in preventing and/or treating allergic disorders, but the results are often quite contradictory, probably because of the heterogeneity of strains, the duration of therapy and the doses administered to patients. Therefore, new studies are needed in order to clarify the functions and the utility of probiotics in food allergies and ion other types of allergic disorders.

Reduced gut microbial diversity in early life is associated with later development of eczema but not atopy in high-risk infants

BACKGROUND

Alterations in intestinal microflora have been linked to the development of allergic disease. Recent studies suggest that healthy infant immune development may depend on the establishment of a diverse gut microbiota rather than the presence or absence of specific microbial strains.

OBJECTIVES

We investigated the relationship between diversity of gut microbiota in the early postnatal period and subsequent development of eczema and atopy in the first year of life.

METHODS

Fecal samples were collected 1 wk after birth from 98 infants at high risk of allergic disease, who were followed prospectively to age 12 months. Fecal microbial diversity was assessed by terminal restriction fragment length polymorphism (T-RFLP) using restriction enzymes Sau96I and AluI, with a greater number of peaks representing greater diversity of bacterial communities.

RESULTS

Microbial diversity at day 7 was significantly lower in infants with eczema at age 12 months as compared to infants without eczema (AluI mean number of peaks 13.1 vs. 15.5, p = 0.003, 95% CI for difference in means -3.9, -0.8; Sau96I 14.7 vs. 17.2, p = 0.03, 95% CI -4.9, -0.3). No differences were observed for atopic compared to non-atopic infants, or infants with two allergic parents compared to those with one or no allergic parent.

CONCLUSIONS

A more diverse intestinal microbiota in the first week of life is associated with a reduced risk of subsequent eczema in infants at increased risk of allergic disease. Interventions that enhance microbial diversity in early life may provide an effective means for the prevention of eczema in high-risk infants.

Can nutritional modulation of maternal intestinal microbiota influence the development of the infant gastrointestinal tract?

The gastrointestinal microbiota plays an important role in maintaining host health by preventing the colonization of pathogens, fermenting dietary compounds, and maintaining normal mucosal immunity. Particularly in early life, the composition of the microbiota profoundly influences the development and maturation of the gastrointestinal tract (GIT) mucosa, which may affect health in later life. Therefore, strategies to manipulate the microbiota during infancy may prevent the development of some diseases later in adult life. Earlier research suggested that term fetuses are sterile and that the initial bacterial colonization of the newborn GIT occurs only after the baby transits through the birth canal. However, recent studies have demonstrated that the colonization and/or contact of the fetus with the maternal GIT microbiota may start in utero. After vaginal birth, the colonization of the neonate GIT continues through contact with maternal feces and vaginal bacteria, leading to a relatively simple microbial community that is influenced by feeding type (breast vs. formula feeding). Maternal GIT microbiota, vaginal microbiota, and breast milk composition are influenced by maternal diet. Alterations of the maternal GIT microbiota composition via supplementation with probiotics and prebiotics have been shown; however, transfer of these benefits to the offspring remains to be demonstrated. This review focuses on the influence of maternal GIT microbiota during the pre- and postpartum periods on the colonization of the infant GIT. In particular, it examines the manipulation of the maternal GIT microbiota composition through the use of probiotics and/or prebiotics and subsequent consequences for the health of the offspring.

A randomized trial of Lactobacillus plantarum CJLP133 for the treatment of atopic dermatitis

BACKGROUND

There have been considerable disagreements regarding the therapeutic effects of probiotics in atopic dermatitis (AD). We performed this study to examine whether the oral administration of Lactobacillus plantarum CJLP133 improves pediatric AD.

METHODS

In a randomized, double-blind, placebo-controlled study, either L. plantarum CJLP133 at a dosage of 0.5 × 10(10) colony-forming units or placebo in children aged 12 months to 13 yr was given twice a day for 12 wk. SCOring of Atopic Dermatitis (SCORAD) scores, eosinophil counts, serum total IgE, and cytokines were evaluated.

RESULTS

Forty-four of 58 patients in the probiotic group and 39 of 60 patients in the placebo group completed the study. The SCORAD score at week 14 was lower in the probiotic group than in the placebo group (p = 0.044). The mean change in the SCORAD score from weeks 2 to 14 was 9.1 in the probiotic group, which was greater than the mean change of 1.8 in the placebo group (p = 0.004). No statistical differences in the total use of topical corticosteroids were found between two groups (p = 0.815). In the probiotic group, the total eosinophil count was significantly lower at the end of the intervention compared to the baseline measurements (p = 0.023). Logarithmic IFN-γ and IL-4 were significantly decreased by the end of the intervention compared to baseline measurements in the probiotic group (p < 0.001 and 0.049).

CONCLUSIONS

Our results suggest that supplementation with probiotic L. plantarum CJLP133 is beneficial in the treatment of pediatric AD.

Microbial ecology and host-microbiota interactions during early life stages

The role of human microbiota has been redefined during recent years and its physiological role is now much more important than earlier understood. Intestinal microbial colonization is essential for the maturation of immune system and for the developmental regulation of the intestinal physiology. Alterations in this process of colonization have been shown to predispose and increase the risk to disease later in life. The first contact of neonates with microbes is provided by the maternal microbiota. Moreover, mode of delivery, type of infant feeding and other perinatal factors can influence the establishment of the infant microbiota. Taken into consideration all the available information it could be concluded that the exposure to the adequate microbes early in gestation and neonatal period seems to have a relevant role in health. Maternal microbial environment affects maternal and fetal immune physiology and, of relevance, this interaction with microbes at the fetal-maternal interface could be modulated by specific microbes administered to the pregnant mother. Indeed, probiotic interventions aiming to reduce the risk of immune-mediated diseases may appear effective during early life.