Gut microbiome in the first 1000 days and risk for childhood food allergy.

OBJECTIVE: To summarize recent data on the association between gut microbiome composition and food allergy (FA) in early childhood and highlight potential host-microbiome interactions that reinforce or abrogate oral tolerance. DATA SOURCES: PubMed search of English-language articles related to FA, other atopic disease, and the gut microbiome in pregnancy and early childhood. STUDY SELECTIONS: Human studies published after 2015 assessing the relationship between the gut bacteriome and virome in the first 2 years of life and FA or food sensitization development in early childhood were prioritized. Additional human studies conducted on the prenatal gut microbiome or other atopic diseases and preclinical studies are also discussed. RESULTS: Children who developed FA harbored lower abundances of Bifidobacterium and Clostridia species and had a less mature microbiome during infancy. The early bacterial microbiome protects against FA through production of anti-inflammatory metabolites and induction of T regulatory cells and may also affect FA risk through a role in trained immunity. Infant enteric phage communities are related to childhood asthma development, though no data are available for FA. Maternal gut microbiome during pregnancy is associated with childhood FA risk, potentially through transplacental delivery of maternal bacterial metabolites, though human studies are lacking. CONCLUSION: The maternal and infant microbiomes throughout the first 1000 days of life influence FA risk through a number of proposed mechanisms. Further large, longitudinal cohort studies using taxonomic, functional, and metabolomic analysis of the bacterial and viral microbiomes are needed to provide further insight on the host-microbe interactions underlying FA pathogenesis in childhood.

Sex-specific biobehavioral regulation of persistent inflammatory pain by alcohol.

BACKGROUND: Although a large percentage of chronic pain patients consume alcohol to manage their pain, there is a significant gap in knowledge regarding the mechanisms underlying the antinociceptive effects of alcohol. METHODS: To determine the longitudinal analgesic effects of alcohol, we utilized the complete Freund's adjuvant (CFA) model of inflammatory pain in adult female and male Wistar rats. Both somatic and negative motivational aspects of pain were measured using the electronic von Frey (mechanical nociception) system, thermal probe test (thermal nociception), and mechanical conflict avoidance task (pain avoidance-like behavior). Tests were conducted at baseline and 1 and 3 weeks following intraplantar CFA or saline administration. At both time points post-CFA, animals were treated with each of three doses of alcohol (intraperitoneal; 0, 0.5, and 1.0 g/kg) over separate days in a Latin square design. RESULTS: Alcohol produced dose-dependent mechanical analgesia and antihyperalgesia in females but only antihyperalgesia in males. Although alcohol continued to attenuate CFA-induced decreases in both thermal and mechanical nociceptive thresholds between 1 and 3 weeks post-CFA, it appeared less effective at increasing thresholds 3 weeks after CFA induction. CONCLUSIONS: These data suggest that individuals may develop tolerance to alcohol's ability to alleviate both somatic and negative motivational symptoms of chronic pain over time. We also discovered sex-specific neuroadaptations in protein kinase A-dependent phosphorylation of GluR1 subunits and extracellular signal-regulated kinase (ERK 1/2) phosphorylation in nociceptive brain centers of animals receiving an alcohol challenge 1 week post-CFA. Together, these findings illustrate a sex-specific regulation of behavioral and neurobiological indices of persistent pain by alcohol.

Agmatine reduces alcohol drinking and produces antinociceptive effects in rodent models of alcohol use disorder.

Alcohol use disorder (AUD) is a chronic, relapsing disorder characterized by an escalation of drinking and the emergence of negative affective states over time. Within this framework, alcohol may be used in excessive amounts to alleviate withdrawal-related symptoms, such as hyperalgesia. Future effective therapeutics for AUD may need to exhibit the ability to reduce drinking as well as to alleviate co-morbid conditions such as pain, and to take mechanistic sex differences into consideration. Agmatine is an endogenous neuromodulator that has been previously implicated in the regulation of reward and pain processing. In the current set of studies, we examined the ability of agmatine to reduce escalated ethanol drinking in complementary models of AUD where adult male and female mice and rats were made dependent via chronic, intermittent ethanol vapor exposure (CIE). We also examined the ability of agmatine to modify thermal and mechanical sensitivity in alcohol-dependent male and female rats. Agmatine reduced alcohol drinking in a dose-dependent fashion, with somewhat greater selectivity in alcohol-dependent female mice (versus non-dependent female mice), but equivalent efficacy across male mice and both groups of male and female rats. In mice and female rats, this efficacy did not extend to sucrose drinking, indicating some selectivity for ethanol reinforcement. Female rats made dependent on alcohol demonstrated significant hyperalgesia symptoms, and agmatine produced dose-dependent antinociceptive effects across both sexes. While additional mechanistic studies into agmatine are necessary, these findings support the broad-based efficacy of agmatine to treat co-morbid excessive drinking and pain symptoms in the context of AUD.

Gut microbiome and breast-feeding: Implications for early immune development.

Establishment of the gut microbiome during early life is a complex process with lasting implications for an individual's health. Several factors influence microbial assembly; however, breast-feeding is recognized as one of the most influential drivers of gut microbiome composition during infancy, with potential implications for function. Differences in gut microbial communities between breast-fed and formula-fed infants have been consistently observed and are hypothesized to partially mediate the relationships between breast-feeding and decreased risk for numerous communicable and noncommunicable diseases in early life. Despite decades of research on the gut microbiome of breast-fed infants, there are large scientific gaps in understanding how human milk has evolved to support microbial and immune development. This review will summarize the evidence on how breast-feeding broadly affects the composition and function of the early-life gut microbiome and discuss mechanisms by which specific human milk components shape intestinal bacterial colonization, succession, and function.

Biomarkers of Development of Immunity and Allergic Diseases in Farming and Non-farming Lifestyle Infants: Design, Methods and 1 Year Outcomes in the "Zooming in to Old Order Mennonites" Birth Cohort Study.

Traditional farming lifestyle has been shown to be protective against asthma and allergic diseases. The individual factors that appear to be associated with this "farm-life effect" include consumption of unpasteurized farm milk and exposure to farm animals and stables. However, the biomarkers of the protective immunity and those associated with early development of allergic diseases in infancy remain unclear. The "Zooming in to Old Order Mennonites (ZOOM)" study was designed to assess the differences in the lifestyle and the development of the microbiome, systemic and mucosal immunity between infants born to traditional farming lifestyle at low risk for allergic diseases and those born to urban/suburban atopic families with a high risk for allergic diseases in order to identify biomarkers of development of allergic diseases in infancy. 190 mothers and their infants born to Old Order Mennonite population protected from or in Rochester families at high risk for allergic diseases were recruited before birth from the Finger Lakes Region of New York State. Questionnaires and samples are collected from mothers during pregnancy and after delivery and from infants at birth and at 1-2 weeks, 6 weeks, 6, 12, 18, and 24 months, with 3-, 4-, and 5-year follow-up ongoing. Samples collected include maternal blood, stool, saliva, nasal and skin swabs and urine during pregnancy; breast milk postnatally; infant blood, stool, saliva, nasal and skin swabs. Signs and symptoms of allergic diseases are assessed at every visit and serum specific IgE is measured at 1 and 2 years of age. Allergic diseases are diagnosed by clinical history, exam, and sensitization by skin prick test and/or serum specific IgE. By the end of the first year of life, the prevalence of food allergy and atopic dermatitis were higher in ROC infants compared to the rates observed in OOM infants as was the number of infants sensitized to foods. These studies of immune system development in a population protected from and in those at risk for allergic diseases will provide critical new knowledge about the development of the mucosal and systemic immunity and lay the groundwork for future studies of prevention of allergic diseases.

Microbial Interrelationships across Sites of Breastfeeding Mothers and Infants at 6 Weeks Postpartum.

Infancy is a critical life stage for the establishment of the gut microbiome. Human milk contains a unique microbial ecosystem that serves as a continuous source of commensal bacteria for the infant. However, the origin of the human milk microbiota, how it is influenced by breastfeeding exclusivity, and its role in infant gut microbiota assembly are not clear. To interrogate these questions, we examined the relationships among fecal, oral, breast skin, and human milk microbiota of 33 exclusively breastfeeding (EBF) and mixed-feeding (MF; human milk + infant formula) mother-infant pairs at 6 weeks postpartum. Here, we show that MF infants have a significantly more diverse oral microbiome comprised of lower relative abundances of Streptococcus and Gemella and higher abundances of Veillonella. Using both SourceTracker2 and FEAST, we demonstrate breast skin and infant saliva as the principal contributing sources to the human milk microbiota. Of the sampled sites, human milk and maternal stool were predicted to contribute the largest fraction to the infant fecal microbiome, but the majority of the community was estimated to arise from unknown sources. Lastly, we identified twenty-one significant co-occurrence relationships between bacteria in human milk and on other maternal and infant body sites. These results demonstrate several unique microbial interrelationships between breastfeeding dyads, providing insight into potential mechanisms of microbial assembly in early life.

Predictors and biomarkers of food allergy and sensitization in early childhood.

OBJECTIVE: To review existing literature on the early risk factors for and biomarkers of food allergy (FA) and food sensitization (FS) and highlight opportunities for future research that will further the understanding of FA pathogenesis in infancy and toddlerhood. DATA SOURCES: PubMed search of English-language articles related to FA and atopic disease. STUDY SELECTIONS: Human studies with outcomes related to FA, FS, and other atopic disease in childhood were selected and reviewed. Studies published after 2015 were prioritized. RESULTS: The prevalence of FA has greatly increased in recent decades and is now a global public health concern. A complex network of early life risk factors has been associated with development of FA and FS in childhood. Food allergy has a genetic component, but recent evidence suggests that interactions between risk alleles and other environmental exposures are important for disease pathogenesis, potentially through epigenetic mechanisms. Lifestyle factors, such as delivery mode, antibiotic use, and pet exposure also influence FA risk, which may be through their effect on the early life gut microbiome. How these early life risk factors, along with route and timing of antigen exposure, collectively target the developing immune system remains an ongoing and important area of study. CONCLUSION: The current body of evidence emphasizes the first 1000 days of life as a critical period for FA development. More observational studies and adequately powered clinical trials spanning early pregnancy through childhood are needed to identify novel biomarkers and risk factors that can predict susceptibility toward or protection against FA.

Pretreatment Adherence to a Priori-Defined Dietary Patterns Is Associated with Decreased Nutrition Impact Symptom Burden in Head and Neck Cancer Survivors.

Dietary intake is understood to contribute to nutrition impact symptoms (NIS) in patients with head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to evaluate the performance of four a priori-defined diet quality indices on the presence of NIS 1 year following diagnosis using data on 323 participants from the University of Michigan Head and Neck Specialized Program of Research Excellence (UM-SPORE). Pretreatment dietary intake was measured before treatment initiation using a food frequency questionnaire. NIS were measured along seven subdomains. Multivariable binary logistic regression models were constructed to evaluate relationships between pretreatment scores on a priori-defined diet quality indices (AHEI-2010, aMED, DASH, and a low-carbohydrate score) and the presence of individual symptoms in addition to a composite "symptom summary score" 1-year postdiagnosis. There were several significant associations between different indices and individual NIS. For the symptom summary score, there were significant inverse associations observed for aMED (ORQ5-Q1: 0.36, 95% CI: 0.14-0.88, ptrend = 0.04) and DASH (ORQ5-Q1: 0.38, 95% CI: 0.15-0.91, ptrend = 0.02) and the presence of NIS 1-year postdiagnosis. Higher adherence to the aMED and DASH diet quality indices before treatment may reduce NIS burden at 1-year postdiagnosis.

Microbiome Composition in Pediatric Populations from Birth to Adolescence: Impact of Diet and Prebiotic and Probiotic Interventions.

Diet is a key regulator of microbiome structure and function across the lifespan. Microbial colonization in the first year of life has been actively researched; however, studies during childhood are sparse. Herein, the impact of dietary intake and pre- and probiotic interventions on microbiome composition of healthy infants and children from birth to adolescence is discussed. The microbiome of breastfed infants has lower microbial diversity and richness, higher Proteobacteria, and lower Bacteroidetes and Firmicutes than those formula-fed. As children consume more complex diets, associations between dietary patterns and the microbiota emerge. Like adults, the microbiota of children consuming a Western-style diet is associated with greater Bacteroidaceae and Ruminococcaceae and lower Prevotellaceae. Dietary fibers and pre- or/and probiotics have been tested to modulate the gut microbiota in early life. Human milk oligosaccharides and prebiotics added to infant formula are bifidogenic and decrease pathogens. In children, prebiotics, such as inulin, increase Bifidobacterium abundance and dietary fibers reduce fecal pH and increase alpha diversity and calcium absorption. Probiotics have been administered to the mother during pregnancy and breastfeeding or directly to the infant/child. Findings on maternal probiotic administration on bacterial taxa are inconsistent. When given directly to the infant/child, some changes in individual taxa are observed, but rarely is overall alpha or beta diversity affected. Cesarean-delivered infants appear to benefit to a greater degree than those born vaginally. Infancy and childhood represent an opportunity to beneficially manipulate the microbiome through dietary or prebiotic interventions, which has the potential to affect both short- and long-term health outcomes.

Sources of Information and Support for Breastfeeding: Alignment with Centers for Disease Control and Prevention Strategies.

BACKGROUND AND OBJECTIVES: Research consistently supports health benefits of breastfeeding; however, rates in the United States remain below Healthy People 2020 goals. To increase breastfeeding, information and support are needed from multiple sources. Given differences in breastfeeding rates by demographic characteristics, sources of information and support may also differ. In addition, recent research suggests potential differences in health outcomes related to feeding method (direct breastfeeding only, feeding expressed human milk, combination-feeding with formula). This study examined (1) information and support received within Centers for Disease Control and Prevention (CDC)-defined strategies for supporting breastfeeding mothers, (2) differences in rates of information and support received by demographics, and (3) associations with feeding method at 6 weeks postpartum. MATERIALS AND METHODS: A sample of 447 women participating in the Synergistic Theory Research Obesity and Nutrition Group (STRONG) Kids 2 study completed surveys with questions from the CDC Survey on Infant Feeding Practices II related to sources of information and support for breastfeeding and breast pump use, and about demographics and feeding method at 6 weeks postpartum. RESULTS: Frequencies of supports received within each category indicate that professional supports were the most pervasive, followed by support from friends and relatives. However, women at greater risk for breastfeeding cessation (lower education, Women, Infants, and Children participants, single mothers) received information and support at lower rates. Education and information support was the only source significantly associated with feeding method. CONCLUSION: New approaches are needed to increase efficacy of information delivery, especially for at-risk populations, to better meet CDC recommendations.

The role of early life nutrition in the establishment of gastrointestinal microbial composition and function.

The development of the human infant intestinal microbiota is a sequential process that begins in utero and continues during the first 2 to 3 years of life. Microbial composition and diversity are shaped by host genetics and multiple environmental factors, of which diet is a principal contributor. An understanding of this process is of clinical importance as the microbiota acquired in early life influence gastrointestinal, immune and neural development, and reduced microbial diversity or dysbiosis during infancy is associated with disorders in infancy and later childhood. The goal of this article was to review the published literature that used culture-independent methods to describe the development of the gastrointestinal microbiota in breast- and formula-fed human infants as well as the impact of prebiotic and probiotic addition to infant formula, and the addition of solid foods.

Assessing appetitive choice discrimination learning in zebrafish.

Within the last decade, the zebrafish (Danio rerio) has emerged as an important vertebrate model in developmental biology and medicine for problems typically associated with humans. However, where behavioral assays are needed, the utility of the zebrafish model has been limited by the narrow range of procedures so far developed to investigate zebrafish learning. The purpose of this study was to further develop and test procedures to study appetitive choice discrimination learning in zebrafish. Zebrafish were conditioned to swim into one of three chambers for food reinforcement. The correct (S+) chamber on a trial was signaled by the presence of a light stimulus in the chamber; the two negative (S-) chambers were dark. Each of the 15 fish tested learned the discrimination to a criterion of 80% correct in both of two consecutive sessions. Tests for stimulus control showed that discriminative behavior was indeed under the control of the S+ discriminandum. These results were discussed in relation to the recent report of zebrafish discrimination learning in a two-alternative task, and the importance of examining individual zebrafish learning curves.