Role of postnatal acquisition of the intestinal microbiome in the early development of immune function

Food-derived bioactive peptides potentiating therapeutic intervention in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects the joints of the human body and is projected to have a prevalence age-standardized rate of 1.5 million new cases worldwide by 2030. Several conventional and non-conventional preventive and therapeutic interventions have been suggested but they have their side effects including nausea, abdominal pain, liver damage, ulcers, heightened blood pressure, coagulation, and bleeding. Interestingly, several food-derived peptides (FDPs) from both plant and animal sources are increasingly gaining a reputation for their potential in the management or therapy of RA with little or no side effects. In this review, the concept of inflammation, its major types (acute and chronic), and RA identified as a chronic type were discussed based on its pathogenesis and pathophysiology. The conventional treatment options for RA were briefly outlined as the backdrop of introducing the FDPs that potentiate therapeutic effects in the management of RA.

A toxic environment selects for specialist microbiome in poison frogs

Shifts in microbiome community composition can have large effects on host health. It is therefore important to understand how perturbations, like those caused by the introduction of exogenous chemicals, modulate microbiome community composition. In poison frogs within the family Dendrobatidae, the skin microbiome is exposed to the alkaloids that the frogs sequester from their diet and use for defense. Given the demonstrated antimicrobial effects of these poison frog alkaloids, these compounds may be structuring the skin microbial community. To test this, we first characterized microbial communities from chemically defended and closely related non-defended frogs from Ecuador. Then we conducted a laboratory experiment to monitor the effect of the alkaloid decahydroquinoline (DHQ) on the microbiome of a single frog species. In both the field and lab experiments, we found that alkaloid-exposed microbiomes are more species rich and phylogenetically diverse, with an increase in rare taxa. To better understand the strain-specific behavior in response to alkaloids, we cultured microbial strains from poison frog skin and found the majority of strains exhibited either enhanced growth or were not impacted by the addition of DHQ. Additionally, stable isotope tracing coupled to nanoSIMS suggests that some of these strains are able to metabolize DHQ. Taken together, these data suggest that poison frog chemical defenses open new niches for skin-associated microbes with specific adaptations, including the likely metabolism of alkaloids, that enable their survival in this toxic environment. This work helps expand our understanding of how exposure to exogenous compounds like alkaloids can impact host microbiomes.

The Nonbacterial Microbiome: Fungal and Viral Contributions to the Preterm Infant Gut in Health and Disease

The intestinal microbiome is frequently implicated in necrotizing enterocolitis (NEC) pathogenesis. While no particular organism has been associated with NEC development, a general reduction in bacterial diversity and increase in pathobiont abundance has been noted preceding disease onset. However, nearly all evaluations of the preterm infant microbiome focus exclusively on the bacterial constituents, completely ignoring any fungi, protozoa, archaea, and viruses present. The abundance, diversity, and function of these nonbacterial microbes within the preterm intestinal ecosystem are largely unknown. Here, we review findings on the role of fungi and viruses, including bacteriophages, in preterm intestinal development and neonatal intestinal inflammation, with potential roles in NEC pathogenesis yet to be determined. In addition, we highlight the importance of host and environmental influences, interkingdom interactions, and the role of human milk in shaping fungal and viral abundance, diversity, and function within the preterm intestinal ecosystem.

"The Yak"-A remarkable animal living in a harsh environment: An overview of its feeding, growth, production performance, and contribution to food security

Yaks play an important role in the livelihood of the people of the Qinghai-Tibet Plateau (QTP) and contribute significantly to the economy of the different countries in the region. Yaks are commonly raised at high altitudes of ~ 3,000-5,400 m above sea level. They provide many important products, namely, milk, meat, fur, and manure, as well as social status, etc. Yaks were domesticated from wild yaks and are present in the remote mountains of the QTP region. In the summer season, when a higher quantity of pasture is available in the mountain region, yaks use their long tongues to graze the pasture and spend ~ 30-80% of their daytime grazing. The remaining time is spent walking, resting, and doing other activities. In the winter season, due to heavy snowfall in the mountains, pasture is scarce, and yaks face feeding issues due to pasture scarcity. Hence, the normal body weight of yaks is affected and growth retardation occurs, which consequently affects their production performance. In this review article, we have discussed the domestication of yaks, the feeding pattern of yaks, the difference between the normal and growth-retarded yaks, and also their microbial community and their influences. In addition, blood biochemistry, the compositions of the yaks' milk and meat, and reproduction are reported herein. Evidence suggested that yaks play an important role in the daily life of the people living on the QTP, who consume milk, meat, fur, use manure for fuel and land fertilizer purposes, and use the animals for transportation. Yaks' close association with the people's well-being and livelihood has been significant.

The Effectiveness of Kangaroo Mother Care (KMC) on attachment of mothers with premature infants

Objective

Attachment is a socio-emotional relationship between the mother and infant that increases the probability of a preterm infant's survival. This study aimed to evaluate the effectiveness of Kangaroo Mother Care (KMC) on maternal attachments of mothers with premature infants.

Study design

This quasi-experimental study was performed on 100 mothers of premature infants who were admitted to neonatal intensive care units. A questionnaire comprising demographic information and the Maternal Attachment Scale were used as data collection tools. All data analysis was performed using SPSS software version 25. Significant level is considered P < 0.05.

Results

After the intervention, the levels of maternal attachment of mothers in the intervention group were significantly higher than in the control group (47.7 ± 2.9vs. 40.4 ± 5.4, P = 0.003). After the intervention, the infants in the intervention group has a significantly higher number of breastfeeding than the control group (10.6 ± 1.8 vs. 8.2 ± 1.6, P = 0.000). Moreover, the infant of the intervention group had a statistically significant higher weight at discharge time (2164.4 ± 481.1 vs. 1965.2 ± 372, P = 0.042).

Conclusion

The results of the present study showed that Kangaroo Mother Care can be used to improve the maternal attachments in mothers with premature infants. It improves the breastfeeding and weight gain status in infants as well.

Aberrant newborn T cell and microbiota developmental trajectories predict respiratory compromise during infancy

Neonatal immune-microbiota co-development is poorly understood, yet age-appropriate recognition of - and response to - pathogens and commensal microbiota is critical to health. In this longitudinal study of 148 preterm and 119 full-term infants from birth through one year of age, we found that postmenstrual age or weeks from conception is a central factor influencing T cell and mucosal microbiota development. Numerous features of the T cell and microbiota functional development remain unexplained; however, by either age metric and are instead shaped by discrete perinatal and postnatal events. Most strikingly, we establish that prenatal antibiotics or infection disrupt the normal T cell population developmental trajectory, influencing subsequent respiratory microbial colonization and predicting respiratory morbidity. In this way, early exposures predict the postnatal immune-microbiota axis trajectory, placing infants at later risk for respiratory morbidity in early childhood.

The Change of Cytokines and Gut Microbiome in Preterm Infants for Bronchopulmonary Dysplasia

Background

Bronchopulmonary dysplasia (BPD) is a devastating form of chronic lung disease that develops in preterm infants. BPD is speculated to arise from abnormal inflammatory responses, which is related to the composition of commensal microbiota, leading us to hypothesize that BPD susceptibility could be influenced by gut microbiota through inflammatory responses. This study is aimed to detect cytokines and the differences in fecal gut microbial composition in the BPD patients.

Methods

Between June 2018 and June 2020, preterm infants born at gestational age ≤30 weeks were recruited. The clinical data of infant characteristics were collected. On days 3–7 and 14–28 after birth, fresh stool samples and serum were collected. The gut microbiota composition between the BPD group and controls was detected by 16S rRNA sequencing. On days 3–7 and days 14–28, ten cytokines including IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, IFN-γ, and TNF-α were detected in the serum.

Results

This study enrolled 38 preterm infants; the number of preterm infants in the BPD group and control group was, respectively, 18 and 20. The gestational age (27.4 ± 1.5 weeks vs. 29.5 ± 0.9 weeks, p = 0.000) and birth weight (971 ± 240 g vs. 1262 ± 335 g, p = 0.000) of the BPD group were lower than those of the control group. The present study found that the BPD group had high levels of IL-1β, IL-4, IL-6, IL-8, and TNF-α, whereas IL-10 was decreased. The Shannon diversity index of the BPD group was lower. The relative abundances of Proteobacteria in BPD group increased significantly from days 3–7 to days 14–28, while the Firmicutes was decreased. On days 14–28, the relative abundances of Proteobacteria in BPD group were significantly higher than those in the control group, while the Firmicutes was lower.

Conclusion

Bronchopulmonary dysplasia could be influenced by gut microbiota through inflammatory responses. More studies are needed to explore the imbalance of cytokines and microbiome in BPD infants and whether it could be reversed by probiotics. This study provided a novel perspective for treating BPD.

Association Between Gastrointestinal Symptoms and Depression in a Representative Sample of Adults in the United States: Findings From National Health and Nutrition Examination Survey (2005-2016)

BACKGROUND

The microbiome's role in the etiology of depression has been a topic of many recent investigations. Findings suggest that dysbiosis, which describes a general disturbance in the gut microbiome, underlies negative gastrointestinal symptoms and is implicated in depression. We studied associations between gastrointestinal symptoms and depressive symptoms at a population level using cross-sectional data from the National Health and Nutrition Examination Survey (2005-2016, n = 36,287). We hypothesized that the odds of depressive symptoms would be significantly higher in those showing signs of gastrointestinal distress.

METHODS

We analyzed 31,191 adults participating in the National Health and Nutrition Examination Survey from 2005-2016. Outcomes included presence of mucus or liquid in bowel leakage and stomach illness in the past month, diarrhea in the past year, and number of weekly bowel movements. The survey (and thus, our analyses) does not include microbiome samples, only self-reported gastrointestinal symptoms. Depressive symptoms were measured using the Patient Health Questionnaire. Moderate, moderately severe, and severe scores were coded as a positive outcome.

RESULTS

Compared to those without depressive symptoms, those with moderate-to-severe depressive symptoms had elevated odds of bowel mucus (odds ratio = 2.78; 95% confidence interval = 1.82-4.24), bowel liquid (odds ratio = 2.16; 95% confidence interval = 1.63-2.86), stomach illness (odds ratio = 1.82; 95% confidence interval = 1.31-2.53), diarrhea (sometimes vs. never odds ratio = 1.72; 95% confidence interval = 1.30-2.29), and constipation (sometimes vs. never odds ratio = 2.76; 95% confidence interval = 2.11-3.62). Overall, those with gastrointestinal symptoms were significantly more likely to have depressive symptoms.

CONCLUSIONS

While the intricacies of the brain-gut axis are being investigated at the molecular level, these population data provide further evidence for the association between depressive symptoms and signs of dysbiosis, which may inform health care providers' patient interactions.

Temporal airway microbiome changes related to ventilator-associated pneumonia in children

We sought to determine whether temporal changes in the lower airway microbiome are associated with ventilator-associated pneumonia (VAP) in children.Using a multicentre prospective study of children aged 31 days to 18 years requiring mechanical ventilation support for >72 h, daily tracheal aspirates were collected and analysed by sequencing of the 16S rRNA gene. VAP was assessed using 2008 Centers for Disease Control and Prevention paediatric criteria. The association between microbial factors and VAP was evaluated using joint longitudinal time-to-event modelling, matched case-control comparisons and unsupervised clustering.Out of 366 eligible subjects, 66 (15%) developed VAP at a median of 5 (interquartile range 3-5) days post intubation. At intubation, there was no difference in total bacterial load (TBL), but Shannon diversity and the relative abundance of Streptococcus, Lactobacillales and Prevotella were lower for VAP subjects versus non-VAP subjects. However, higher TBL on each sequential day was associated with a lower hazard (hazard ratio 0.39, 95% CI 0.23-0.64) for developing VAP, but sequential values of diversity were not associated with VAP. Similar findings were observed from the matched analysis and unsupervised clustering. The most common dominant VAP pathogens included Prevotella species (19%), Pseudomonas aeruginosa (14%) and Streptococcus mitis/pneumoniae (10%). Mycoplasma and Ureaplasma were also identified as dominant organisms in several subjects.In mechanically ventilated children, changes over time in microbial factors were marginally associated with VAP risk, although these changes were not suitable for predicting VAP in individual patients. These findings suggest that focusing exclusively on pathogen burden may not adequately inform VAP diagnosis.

Primary Human Dendritic Cells and Whole-Blood Based Assays to Evaluate Immuno-Modulatory Properties of Heat-Killed Commensal Bacteria

There is mounting evidence that the microbiome plays a critical role in training and maturation of the host immune system. Pre-clinical and clinical studies have shown that microbiome perturbation is correlated with sub-optimal host responses to vaccines and cancer immunotherapy. As such, identifying species of commensal bacteria capable of modulating immunological outcomes is of considerable interest. Currently, the lack of reliable primary immune cell-based assays capable of differentiating immuno-modulatory properties of various commensal bacteria is a major limitation. Here, we demonstrate that primary human monocyte-derived dendritic cells (MoDC) are capable of stratifying different strains of live and heat-killed commensal bacteria in an in vitro culture system. Specifically, heat-killed bacterial strains were able to differentially modulate co-stimulation/maturation markers CD80, CD83, and HLA-DR, as well as cytokine/chemokine signatures, such as IL-1b, MIP-1a, and TNFa in primary human MoDC. We further validated our observations using the TruCulture^® (Myriad RBM, Inc., Austin, TX, USA) whole-blood ex vivo culture system. Using this ex vivo system allowed us to measure immune-altering effects of commensal bacteria in primary human whole-blood. As such, we report that both these primary in vitro and ex vivo systems are robust and enable identification, stratification, and differentiation of various commensal bacteria as potential modulators of host immunity.

Perinatal treatment of parents with the broad-spectrum antibiotic enrofloxacin aggravates contact sensitivity in adult offspring mice

BACKGROUND

Antibiotics, while eliminating pathogens, also partially deplete commensal bacteria. Antibiotic-induced dysbiosis may contribute to the observed rise in "immune-mediated" diseases, including autoimmunity and allergy. The aim of this study is to investigate the impact of perinatal antibiotic treatment on T cell-mediated immune response in adult mice.

METHODS

Oral treatment with broad-spectrum antibiotic enrofloxacin during gestation and breastfeeding or breastfeeding or gestation alone was used to evaluate whether antibiotic exposure early in life could modulate contact sensitivity (CS) in adult mice.

RESULTS

Here, we demonstrated that enrofloxacin treatment during gestation and breastfeeding, but not during pregnancy or breastfeeding alone, aggravated CS reaction in adult mice measured by ear swelling. These data correlate with increased myeloperoxidase (MPO) activity in the ear extracts and elevated production of IL-6 and IL-17A by auricular lymph node cells (ELNC) and was not influenced by food consumption and body weight. In each dosing regimen, enrofloxacin treatment reduced the relative abundance of Enterococcus spp. but did not influence the relative abundances of Lactobacillus, Clostridium cluster XIVa, XIVab, I, Bacteroidetes, and segmented filamentous bacteria (SFB). However, prolonged enrofloxacin-treatment during both gestation and breastfeeding decreased the relative abundance of Clostridium cluster IV.

CONCLUSION

These data show that long-term perinatal enrofloxacin treatment induces intestinal dysbiosis, characterized by decreased levels of anti-inflammatory Clostridium cluster IV, and alters T cell-dependent immune responses, enhancing CS reaction in adult mice.

A prebiotic-enhanced lipid-based nutrient supplement (LNSp) increases Bifidobacterium relative abundance and enhances short-chain fatty acid production in simulated colonic microbiota from undernourished infants

Undernutrition remains a public health problem in the developing world with an attributable under-five death proportion of 45%. Lower gut microbiota diversity and poor metabolic output are associated with undernutrition and new therapeutic paths may come from steering gut microbiota composition and functionality. Using a dynamic gut model, the Simulator of Human Intestinal Microbial Ecosystem (SHIME®), we investigated the effect of a lipid-based nutrient supplement enriched with prebiotics (LNSp), compared to LNS alone and control treatment, on the composition and metabolic functionality of fecal microbiota from three infants suffering from undernutrition. LNS elicited a significant increase in acetate and branched-chain fatty acid production, and a higher relative abundance of the genera Prevotella, Megasphaera, Acinetobacter, Acidaminococcus and Pseudomonas. In contrast, LNSp treatment resulted in a significant 9-fold increase in Bifidobacterium relative abundance and a decrease in that of potential pathogens and detrimental bacteria such as Enterobacteriaceae spp. and Bilophila sp. Moreover, the LNSp treatment resulted in a significantly higher production of acetate, butyrate and propionate, as compared to control and LNS. Our results suggest that provision of prebiotic-enhanced LNS to undernourished children could be a possible strategy to steer the microbiota toward a more beneficial composition and metabolic activity. Further in vivo investigations are needed to assess these effects and their repercussion on nutritional status.

The increased susceptibility to airway infections after preterm birth does not persist into adolescence

INTRODUCTION

Preterm birth is associated with increased risk of airway infections in childhood, more frequent purchase of prescription antibiotics and hospital admissions for airway infections. With this study, we aimed to investigate whether this association persists into adolescence.

METHODS

We conducted a longitudinal observational register-based study of a national cohort of all infants born in Denmark in 1992-2007. We used purchase of antibiotics, including penicillins and macrolides, and hospital admissions as proxies for milder and more severe forms of airway infections respectively in 1995-2010. Associations between gestational age (GA), age, year and repeated cross-sectional evaluations of antibiotic purchase and hospital admissions were explored by logistic regression analyses.

RESULTS

We included 1,043,411 children in our study population. We found a statistically significant association between GA and prescription of antibiotics as well as hospital admissions due to airway infections. In the youngest age groups, children with higher GA had lower adjusted mean rates of prescribed antibiotics for airway infections, but from the age of 10-11 years the opposite trend was noted in what appears to be a dose-response relationship. During childhood, we found an inverse dose-response relationship where ex-preterms with GA 23-27 at age 4-5 years had twice the odds of hospital admission compared to children in the same age group born at term. During adolescence, these higher odds diminished and appeared equivalent among teenagers born at term and preterm. We only found statistically significant interactions between gestational age and age.

CONCLUSION

We confirmed that preterm birth is associated with higher rates of prescribed antibiotics and higher odds of hospitalization for airway infections during childhood. However, in adolescence we found that there was no increase in hospital admissions for airway infections among ex-preterms, whereas adolescents with low GA actually appeared to purchase less prescribed antibiotics. Whether this trend persists into adulthood and the physiological explanation therefor remains to be investigated.

The Role of Glycosaminoglycans in Protection from Neonatal Necrotizing Enterocolitis: A Narrative Review

Necrotizing enterocolitis, a potentially fatal intestinal inflammatory disorder affecting primarily premature infants, is a significant cause of morbidity and mortality in neonates. While the etiology of the disease is, as yet, unknown, a number of risk factors for the development of necrotizing enterocolitis have been identified. One such risk factor, formula feeding, has been shown to contribute to both increased incidence and severity of the disease. The protective influences afforded by breastfeeding are likely attributable to the unique composition of human milk, an extremely potent, biologically active fluid. This review brings together knowledge on the pathogenesis of necrotizing enterocolitis and current thinking on the instrumental role of one of the more prominent classes of bioactive components in human breast milk, glycosaminoglycans.

Maternal Obesity as a Risk Factor for Brain Development and Mental Health in the Offspring

Maternal obesity plays a key role in the health trajectory of the offspring. Although research on this topic has largely focused on the potential of this condition to increase the risk for child obesity, it is becoming more and more evident that it can also significantly impact cognitive function and mental health. The mechanisms underlying these effects are starting to be elucidated and point to the placenta as a critical organ that may mediate changes in the response to stress, immune function and oxidative stress. Long-term effects of maternal obesity may rely upon epigenetic changes in selected genes that are involved in metabolic and trophic regulations of the brain. More recent evidence also indicates the gut microbiota as a potential mediator of these effects. Overall, understanding cause-effect relationships can allow the development of preventive measures that could rely upon dietary changes in the mother and the offspring. Addressing diets appears more feasible than developing new pharmacological targets and has the potential to affect the multiple interconnected physiological pathways engaged by these complex regulations, allowing prevention of both metabolic and mental disorders.

Matrotrophic viviparity constrains microbiome acquisition during gestation in a live-bearing cockroach, Diploptera punctata

The vertical transmission of microbes from mother to offspring is critical to the survival, development, and health of animals. Invertebrate systems offer unique opportunities to conduct studies on microbiome-development-reproduction dynamics since reproductive modes ranging from oviparity to multiple types of viviparity are found in these animals. One such invertebrate is the live-bearing cockroach, Diploptera punctata. Females carry embryos in their brood sac, which acts as the functional equivalent of the uterus and placenta. In our study, 16S rRNA sequencing was used to characterize maternal and embryonic microbiomes as well as the development of the whole-body microbiome across nymphal development. We identified 50 phyla and 121 classes overall and found that mothers and their developing embryos had significantly different microbial communities. Of particular interest is the notable lack of diversity in the embryonic microbiome, which is comprised exclusively of Blattabacteria, indicating microbial transmission of only this symbiont during gestation. Our analysis of postnatal development reveals that significant amounts of non-Blattabacteria species are not able to colonize newborn D. punctata until melanization, after which the microbial community rapidly and dynamically diversifies. While the role of these microbes during development has not been characterized, Blattabacteria must serve a critical role providing specific micronutrients lacking in milk secretions to the embryos during gestation. This research provides insight into the microbiome development, specifically with relation to viviparity, provisioning of milk-like secretions, and mother-offspring interactions during pregnancy.

Gut Microbiota and IL-17A: Physiological and Pathological Responses

IL-17A is a cytokine which is produced by several immune and non-immune cells. The cytokine plays dual roles from protection from microbes and protection from pro-inflammatory based diseases to induction of the pro-inflammatory based diseases. The main mechanisms which lead to the controversial roles of IL-17A are yet to be clarified. Gut microbiota (GM) are the resident probiotic bacteria in the gastrointestinal tracts which have been introduced as a plausible regulator of IL-17A production and functions. This review article describes the recent information regarding the roles played by GM in determination of IL-17A functions outcome.

The Lung Microbiome and Its Role in Pneumonia

The use of next-generation sequencing and multiomic analysis reveals new insights on the identity of microbes in the lower airways blurring the lines between commensals and pathogens. Microbes are not found in isolation; rather they form complex metacommunities where microbe-host and microbe-microbe interactions play important roles on the host susceptibility to pathogens. In addition, the lower airway microbiota exert significant effects on host immune tone. Thus, this review highlights the roles that microbes in the respiratory tract play in the development of pneumonia.

Rheumatoid arthritis (RA) and cardiovascular disease

Patients with rheumatoid arthritis (RA) suffer cardiovascular events 1.5-2 fold than the general population, and cardiovascular (CV) events are leading cause of death in patients with RA. It is known that patients with RA have endothelial dysfunction, related with impaired function of endothelial progenitor cells (EPCs). The mechanistic pathways leading to endothelial function are complicated, but understanding these mechanisms may open new frontiers of management and therapies to patients suffering from atherosclerosis. Inflammation is a key factor in atherosclerosis, including endothelial function, plaque stabilization and post infarct remodeling; thus, inhibition of TNF-α may affect the inflammatory burden and plaque vulnerability leading to less cardiovascular events and myocardial infarctions. An aggressive management of inflammation may lead to a significant improvement in the clinical cardiovascular outcome of patients with RA. The clinical evidence that showed a reduced risk of CV events following treatment with anti-inflammatory agents may suggest a new approach to treat atherosclerosis, i.e., inhibition of inflammation using biological medications that were primarily aimed to treat the high scale inflammation of RA and other autoimmune-inflammatory diseases, but may be useful also to prevent progression of atherosclerosis.

Prenatal complications are associated with the postnatal airway host response and microbiota in intubated preterm infants

PURPOSE

To prospectively examine the relationship between prenatal events, postnatal airway host response and microbiota, and clinical outcomes.

MATERIALS AND METHODS

Tracheal aspirates collected at seven days of age from 71 mechanically ventilated infants (median gestational age (GA), 25 weeks [range 23-28]) were simultaneously processed for a 12-plex protein assay and bacterial identification by 16S rRNA sequencing. Phenotypes were determined by unsupervised clustering of the protein analytes. Subject characteristics, microbial communities and clinical factors and outcomes were compared across the phenotype groups.

RESULTS

Three clusters were identified: 1 (high protein levels), 2 (high proinflammatory proteins and low anti-inflammatory proteins), and 3 (low protein levels), respectively. Antenatal hemorrhage was most common in cluster 1, while chorioamnionitis characterized cluster 2 and preeclampsia was most prevalent in cluster 3, which was characterized by a predominance of Staphylococcus and relative absence of Ureaplasma. There were higher rates of adverse clinical outcomes in cluster 1.

CONCLUSIONS

Airway protein profiles in seven days old mechanically ventilated preterm infants are associated with important antenatal events and unique airway microbial communities. These relationships may reveal new mechanisms by which antenatal events impact the course and outcomes of preterm infants.

Follow up on atopy and the gastrointestinal tract - a review of a common association 2018

Primary atopic disorders can be classified as heritable genetic disorders presenting with deregulated pathogenic allergic effector responses irrespective of sensitization. In the last decade, there are parallel rises in the burden of atopic and gastrointestinal (GI) diseases. Areas covered: There is increasing recognition of an association between atopy and GI disease through immune dysregulation, the microbiome and shared genetic pathways. Since the first article on atopy and the GI tract in 2014 in this journal, many more studies have shed light on the shared pathways in these diseases, particularly in the field of eosinophilic GI disease, functional GI disorders, and inflammatory bowel disease. Expert opinion: Understanding the links with common mechanisms in atopy and GI diseases that may lead to better targeting of treatment through manipulation of immune mechanisms, the microbiome, genetics, food allergens and specific GI diseases such as inflammatory bowel disease, functional GI disorders.

The Preterm Gut Microbiota: An Inconspicuous Challenge in Nutritional Neonatal Care

The nutritional requirements of preterm infants are unique and challenging to meet in neonatal care, yet crucial for their growth, development and health. Normally, the gut microbiota has distinct metabolic capacities, making their role in metabolism of dietary components indispensable. In preterm infants, variation in microbiota composition is introduced while facing a unique set of environmental conditions. However, the effect of such variation on the microbiota's metabolic capacity and on the preterm infant's growth and development remains unresolved. In this review, we will provide a holistic overview on the development of the preterm gut microbiota and the unique environmental conditions contributing to this, in addition to maturation of the gastrointestinal tract and immune system in preterm infants. The role of prematurity, as well as the role of human milk, in the developmental processes is emphasized. Current research stresses the early life gut microbiota as cornerstone for simultaneous development of the gastrointestinal tract and immune system. Besides that, literature provides clues that prematurity affects growth and development. As such, this review is concluded with our hypothesis that prematurity of the gut microbiota may be an inconspicuous clinical challenge in achieving optimal feeding besides traditional challenges, such as preterm breast milk composition, high nutritional requirements and immaturity of the gastrointestinal tract and immune system. A better understanding of the metabolic capacity of the gut microbiota and its impact on gut and immune maturation in preterm infants could complement current feeding regimens in future neonatal care and thereby facilitate growth, development and health in preterm infants.

Association between Psychosocial Stress and Fecal Microbiota in Pregnant Women

Maternal prenatal psychosocial stress is associated with altered child emotional and behavioral development. One potential underlying mechanism is that prenatal psychosocial stress affects child outcomes via the mother's, and in turn the child's, intestinal microbiota. This study investigates the first step of this mechanism: the relation between psychosocial stress and fecal microbiota in pregnant mothers. Mothers (N = 70) provided a late pregnancy stool sample and filled in questionnaires on general and pregnancy-specific stress and anxiety. Bacterial DNA was extracted and analysed by Illumina HiSeq sequencing of PCR-amplified 16 S ribosomal RNA gene fragments. Associations between maternal general anxiety and microbial composition were found. No associations between the other measured psychosocial stress variables and the relative abundance of microbial groups were detected. This study shows associations between maternal pregnancy general anxiety and microbial composition, providing first evidence of a mechanism through which psychological symptoms in pregnancy may affect the offspring.

Antibiotics and autoimmune and allergy diseases: Causative factor or treatment?

The newborn infant emerges from an almost sterile environment into a world of bacteria. Bacteria colonize the infant's skin, lungs, and, of most importance, the gut. The process of bacterial colonization is coordinated, and each body niche acquires a unique composition of bacteria. In the gut, most bacteria belong to the Firmicutes and Bacteroidetes phyla, while Actinobacteria and Proteobacteria are far less abundant. Some of these bacteria possess strong immunoregulatory properties. Bacterial colonization is essential to skew the newborn's immune response away from the allergy-favoring Type-2 response towards a Type-1 immune response, which is essential for pathogen elimination. Imbalance between Type 1 and Type 2 responses, however, can promote autoimmunity. In addition, the microbiota shapes immune responses in adults. Autoimmune and allergic diseases are commonly associated with an altered composition of resident bacteria, which is known as dysbiosis. Perhaps the most common cause of disruption and alteration of the bacterial colonization of newborns is the use of antibiotics. It is not known whether the dysbiosis precedes or is the consequence of allergic and autoimmune disorders, and whether antibiotics can be a trigger for these disorders, depending on the type of antibiotic used and the maturity of immune system. In this review, we discuss the development of the microbiota in different body niches and their immunomodulatory potential. We evaluate the impact of antibiotics, both in mice and in humans, on microbial communities and how that may impact the development and manifestation of diseases through all stages of life: the prenatal period, childhood, and adulthood.

Are cortisol concentrations in human breast milk associated with infant crying?

The present longitudinal study is the first to investigate the association between human breast milk cortisol and infant crying over the first three months of life. Higher concentrations of breast milk cortisol were expected to be differentially associated with fussing and crying in boys and girls. At 2, 6, and 12 weeks of infant age, mothers (N = 70) collected a morning sample of their milk and kept a 3‐day diary to measure infant fussing and crying. Cortisol was extracted and quantified from milk samples. Results showed that breast milk cortisol concentrations increased from 2 weeks through 12 weeks of infant age. Milk cortisol was unrelated to the total duration, frequency, and bout length of infant fussing and crying for both boys and girls. Directions for future research aiming to extend our knowledge on the biology of milk cortisol in relation to infant behavior and development are discussed.

Short-term Oral Antibiotics Treatment Promotes Inflammatory Activation of Colonic Invariant Natural Killer T and Conventional CD4+ T Cells

The gut mucosa is continuously exposed to a vast community of microorganisms, collectively defined as microbiota, establishing a mutualistic relationship with the host and contributing to shape the immune system. Gut microbiota is acquired at birth, and its composition is relatively stable during the entire adult life. Intestinal dysbiosis, defined as a microbial imbalance of gut bacterial communities, can be caused by several factors, including bacterial infections and antibiotic use, and has been associated with an increased risk to develop or exacerbate immune-mediated pathologies, such as allergic reactions, asthma, and inflammatory bowel diseases. Still, the mechanisms by which antibiotic-induced gut dysbiosis may lead to development of mucosal inflammation are still matter of debate. To this end, we aimed to evaluate the impact of antibiotic treatment on phenotype and functions of intestinal immune cell populations, including invariant natural killer T (iNKT) cells, a subset of lipid-specific T cells profoundly influenced by alterations on the commensal microbiota. To this aim, a cocktail of broad-spectrum antibiotics was administered for 2 weeks to otherwise healthy mice before re-colonization of the intestinal microbial community with oral gavage of eubiotic or dysbiotic mucosa-associated bacteria and luminal colonic content, followed or not by intestinal inflammation induction. Here. we showed that short-term antibiotic treatment alters frequency and functions of intestinal iNKT cells, even in the absence of intestinal inflammation. The presence of a dysbiotic microbiota after antibiotic treatment imprints colonic iNKT and CD4⁺ T cells toward a pro-inflammatory phenotype that collectively contributes to aggravate intestinal inflammation. Nonetheless, the inflammatory potential of the dysbiotic microbiota decreases over time opening the possibility to temporally intervene on the microbial composition to re-equilibrate dysbiosis, thus controlling concomitantly mucosal immune T cell activations.

IL-17 in neonatal health and disease

Over the last few years, scientific interest in the cytokine IL-17A has intensified as its role in human health and disease has been elucidated. Discovered almost a quarter century ago, IL-17A is known to have poor biologic activity when acting alone, but attains robust actions when working synergistically with potent mediators of proinflammatory immune responses, such as IL-6 and IL-8. IL-17A is produced by specialized innate immune cells that protect host barriers from the outside world. Like sentries, these innate immune cells can "sound the alarm" through increased production of IL-17A, causing activation and recruitment of primed neutrophils and monocytes when pathogens escape initial host defenses. In this way, IL-17A promulgates mechanisms responsible for pathogen death and clearance. However, when IL-17A pathways are triggered during fetal development, due to chorioamnionitis or in utero inflammatory conditions, IL-17A can instigate and/or exacerbate fetal inflammatory responses that increase neonatal morbidities and mortality associated with common neonatal conditions such as sepsis, bronchopulmonary dysplasia (BPD), patent ductus arteriosus (PDA), and necrotizing enterocolitis (NEC). This review details the ontogeny of IL-17A in the fetus and newborn, discusses how derangements in its production can lead to pathology, and describes known and evolving therapies that may attenuate IL-17A-mediated human conditions.

Ventilator-Associated Pneumonia in Critically Ill Children: A New Paradigm

Ventilator-associated pneumonia (VAP) is a serious complication of critical illness. Surveillance definitions have undergone revisions for more objective and consistent reporting. The 1 organism-1 disease paradigm for microbial involvement may not adequately apply to many cases of VAP, in which pathogens are introduced to a pre-existing and often complex microbial community that facilitates or hinders the potential pathogen, consequently determining whether progression to VAP occurs. As omics technology is applied to VAP, a paradigm is emerging incorporating simultaneous assessments of microbial populations and their activity, as well as the host response, to personalize prevention and treatment.

Maternal late pregnancy anxiety and stress is associated with children's health: a longitudinal study

AIM

Maternal prenatal anxiety and stress (PNS) have been positively associated to physical health prob lems in offspring in the first year of life. Whether these associations are transient, persistent, or even progressive over time, is as yet unknown. The goal of this study is to investigate associations between late pregnancy PNS and child health from 18 months to age 6.

METHODS

Mothers were recruited in late pregnancy, and had uncomplicated, singleton pregnancies without physical health problems. Around week 37 of pregnancy, mothers reported on their PNS by means of questionnaires, and provided saliva for determination of circadian cortisol concentrations. Children's illnesses in the preceding year were assessed using maternal reports at 30, 48, 60, and 72 months. Antibiotic use was obtained from medical records between one and six years. Multilevel models (N¼174) showed a positive relation between maternal prenatal general and pregnancy-specific anxiety during late pregnancy and offspring respiratory illnesses and symptoms. Interaction effects with time indicated that more PNS was related to more respiratory illnesses until toddlerhood, but not later in life. Furthermore, maternal prenatal cortisol concentrations were related to child digestive illnesses. A steeper maternal cortisol decline over the day was related to more child digestive illnesses, until around three years of age. Finally, children of mothers who suffered more from daily hassles during pregnancy received more antibiotics between one and six years of age. PNS was not related to general and skin illnesses.

CONCLUSION

Summarizing, this study showed that late pregnancy anxiety and cortisol was associated with children's respiratory and digestive illnesses till the age of 3.0-3.5 years. Additionally, more daily hassles were related to more prescribed antibiotics between one and six years. These findings point in the direction of possible effects of PNS persisting beyond the first year of life and into toddlerhood, but disappearing at older ages.

Effectiveness of skin-to-skin contact versus care-as-usual in mothers and their full-term infants: study protocol for a parallel-group randomized controlled trial

BACKGROUND

Twenty-to-forty percent of women experience postpartum depressive symptoms, which can affect both the mother and infant. In preterm infants, daily skin-to-skin contact (SSC) between the mother and her infant has been shown to decrease maternal postpartum depressive symptoms. In full-term infants, only two studies investigated SSC effects on maternal depressive symptoms and found similar results. Research in preterm infants also showed that SSC improves other mental and physical health outcomes of the mother and the infant, and improves the quality of mother-infant relationship. This randomized controlled trial will investigate the effects of a SSC intervention on maternal postpartum depressive symptoms and additional outcomes in mothers and their full-term infants. Moreover, two potential underlying mechanisms for the relation between SSC and the maternal and infant outcomes will be examined, namely maternal oxytocin concentrations and infant intestinal microbiota.

METHODS/DESIGN

Design: A parallel-group randomized controlled trial.

PARTICIPANTS

116 mothers and their full-term infants.

INTERVENTION

Mothers in the SSC condition will be requested to provide daily at least one continuous hour of SSC to their infant. The intervention starts immediately after birth and lasts for 5 weeks. Mothers in the control condition will not be requested to provide SSC. Maternal and infant outcomes will be measured at 2 weeks, 5 weeks, 12 weeks and 1 year after birth.

PRIMARY OUTCOME

maternal postpartum depressive symptoms. Secondary maternal outcomes: mental health (anxiety, stress, traumatic stress following child birth, sleep quality), physical health (physical recovery from the delivery, health, breastfeeding, physiological stress), mother-infant relationship (mother-infant bond, quality of maternal caregiving behavior). Secondary infant outcomes: behavior (fussing and crying, sleep quality), physical health (growth and health, physiological stress), general development (regulation capacities, social-emotional capacities, language, cognitive and motor capacities). Secondary underlying mechanisms: maternal oxytocin concentrations, infant intestinal microbiota.

DISCUSSION

As a simple and cost-effective intervention, SSC may benefit both the mother and her full-term infant in the short-and long-term. Additionally, if SSC is shown to be effective in low-risk mother-infant dyads, then thought could be given to developing programs in high-risk samples and using SSC in a preventive manner.

TRIAL REGISTRATION

NTR5697 ; Registered on March 13, 2016.

The influence of the commensal microbiota on distal tumor-promoting inflammation

Commensal microbes inhabit barrier surfaces, providing a first line of defense against invading pathogens, aiding in metabolic function of the host, and playing a vital role in immune development and function. Several recent studies have demonstrated that commensal microbes influence systemic immune function and homeostasis. For patients with extramucosal cancers, or cancers occurring distal to barrier surfaces, the role of commensal microbes in influencing tumor progression is beginning to be appreciated. Extrinsic factors such as chronic inflammation, antibiotics, and chemotherapy dysregulate commensal homeostasis and drive tumor-promoting systemic inflammation through a variety of mechanisms, including disruption of barrier function and bacterial translocation, release of soluble inflammatory mediators, and systemic changes in metabolic output. Conversely, it has also been demonstrated that certain immune therapies, immunogenic chemotherapies, and checkpoint inhibitors rely on the commensal microbiota to facilitate anti-tumor immune responses. Thus, it is evident that the mechanisms associated with commensal microbe facilitation of both pro- and anti-tumor immune responses are context dependent and rely upon a variety of factors present within the tumor microenvironment and systemic periphery. The goal of this review is to highlight the various contexts during which commensal microbes orchestrate systemic immune function with a focus on describing possible scenarios where the loss of microbial homeostasis enhances tumor progression.

Airway Microbial Community Turnover Differs by BPD Severity in Ventilated Preterm Infants

Preterm birth exposes the developing lung to an environment with direct exposure to bacteria, often facilitated by endotracheal intubation. Despite evidence linking bacterial infections to the pathogenesis of bronchopulmonary dysplasia (BPD), systematic studies of airway microbiota are limited. The objective was to identify specific patterns of the early respiratory tract microbiome from tracheal aspirates of mechanically ventilated preterm infants that are associated with the development and severity of BPD. Infants with gestational age ≤34 weeks, and birth weight 500-1250g were prospectively enrolled. Mechanically ventilated infants had tracheal aspirate samples collected at enrollment, 7, 14, and 21 days of age. BPD was determined by modified NIH criteria with oxygen reduction tests; infants without BPD were excluded due to low numbers. Aspirates were processed for bacterial identification by 16S rRNA sequencing, and bacterial load by qPCR. Cross-sectional analysis was performed using 7 day samples and longitudinal analysis was performed from subjects with at least 2 aspirates. Microbiome analysis was performed on tracheal aspirates from 152 infants (51, 49, and 52 with mild, moderate, and severe BPD, respectively). Seventy-nine of the infants were included in the cross-sectional analysis and 94 in the longitudinal. Shannon Diversity, bacterial load, and relative abundance of individual taxa were not strongly associated with BPD status. Longitudinal analysis revealed that preterm infants who eventually developed severe BPD exhibited greater bacterial community turnover with age, acquired less Staphylococcus in the first days after birth, and had higher initial relative abundance of Ureaplasma. In conclusion, longitudinal changes in the airway microbial communities of mechanically ventilated preterm infants may be associated with BPD severity, whereas cross-sectional analysis of airway ecology at 7 days of age did not reveal an association with BPD severity. Further evaluation is necessary to determine whether the observed longitudinal changes are causal or in response to clinical management or other factors that lead to BPD.

Reactivation of dormant anti-tumor immunity - a clinical perspective of therapeutic immune checkpoint modulation

In favor of their outgrowth, cancer cells must resist immune surveillance and edit the immune response. Cancer immunoediting is characterized by fundamental changes in the cellular composition and the inflammatory cytokine profiles in the microenvironment of the primary tumor and metastatic niches, with an ever increasing complexity of interactions between tumor cells and the immune system. Recent data suggest that genetic instability and immunoediting are not necessarily disparate processes. Increasing mutational load may be associated with multiple neoepitopes expressed by the tumor cells and thus increased chances for the immune system to recognize and combat these cells. At the same time the immune system is more and more suppressed and exhausted by this process. Consequently, immune checkpoint modulation may have the potential to be most successful in genetically highly altered and usually extremely unfavorable types of cancer. Moreover, the fact that epitopes recognized by the immune system are preferentially encoded by passenger gene mutations opens windows of synergy in targeting cancer-specific signaling pathways by small molecules simultaneously with antibodies modifying T-cell activation or exhaustion.

This review covers some aspects of the current understanding of the immunological basis necessary to understand the rapidly developing therapeutic endeavours in cancer treatment, the clinical achievements made, and raises some burning questions for translational research in this field.

Development of an Antigen-driven Colitis Model to Study Presentation of Antigens by Antigen Presenting Cells to T Cells

Inflammatory bowel disease (IBD) is a chronic inflammation which affects the gastrointestinal tract (GIT). One of the best ways to study the immunological mechanisms involved during the disease is the T cell transfer model of colitis. In this model, immunodeficient mice (RAG(-/-) recipients) are reconstituted with naive CD4(+) T cells from healthy wild type hosts. This model allows examination of the earliest immunological events leading to disease and chronic inflammation, when the gut inflammation perpetuates but does not depend on a defined antigen. To study the potential role of antigen presenting cells (APCs) in the disease process, it is helpful to have an antigen-driven disease model, in which a defined commensal-derived antigen leads to colitis. An antigen driven-colitis model has hence been developed. In this model OT-II CD4(+) T cells, that can recognize only specific epitopes in the OVA protein, are transferred into RAG(-/-) hosts challenged with CFP-OVA-expressing E. coli. This model allows the examination of interactions between APCs and T cells in the lamina propria.

Randomised controlled trial testing the effect of cotrimoxazole prophylaxis on morbidity and mortality outcomes in breastfed HIV-exposed uninfected infants: study protocol

INTRODUCTION

No randomised controlled trial (RCT) has examined the efficacy of cotrimoxazole (CTX) prophylaxis in HIV-exposed uninfected (HEU) infants during the breastfeeding period, in this new era of effective prevention of mother-to-child transmission (PMTCT) prophylaxis. The efficacy of CTX prophylaxis has presently been demonstrated only in HIV-infected children. The absence of proven benefits in HEU breastfed infants associated with infectious diseases justifies an RCT as proposed. Herewith lies the rationale for conducting the proposed study.

METHODS

A partially blinded RCT is proposed to evaluate the efficacy of CTX prophylaxis administered from 6 weeks of age to HEU infants receiving a PMTCT regimen. A non-inferiority design will be used, randomising 1298 infants to receive CTX or not to receive CTX. Participants will be reviewed at the following time points: 6 weeks (enrolment and randomisation), 10 weeks, 14 weeks, 4 months and monthly thereafter until 12 months of age. They will be evaluated for anthropometric growth, interval illness, CTX adherence, signs and symptoms of study drug toxicity, concomitant medication use, breastfeeding status and HIV infection status. The study will compare the incidence of grade 3 and grade 4 common childhood illnesses (focusing on pneumonia and diarrhoea) and all-cause mortality until 12 months of age. In a subset of participants, we will compare grade 3 and grade 4 haemoglobin and alanine aminotransferase results as well as investigate gut integrity.

ETHICS AND DISSEMINATION

The study has ethical approval from the University of KwaZulu-Natal Biomedical Research Ethics Committee (BFC212/13).

TRIAL REGISTRATION NUMBERS

PACTR201311000621110 and DOH-27-0614-4728; Pre-results.

Engineering Human Microbiota: Influencing Cellular and Community Dynamics for Therapeutic Applications

The complex relationship between microbiota, human physiology, and environmental perturbations has become a major research focus, particularly with the arrival of culture-free and high-throughput approaches for studying the microbiome. Early enthusiasm has come from results that are largely correlative, but the correlative phase of microbiome research has assisted in defining the key questions of how these microbiota interact with their host. An emerging repertoire for engineering the microbiome places current research on a more experimentally grounded footing. We present a detailed look at the interplay between microbiota and host and how these interactions can be exploited. A particular emphasis is placed on unstable microbial communities, or dysbiosis, and strategies to reestablish stability in these microbial ecosystems. These include manipulation of intermicrobial communication, development of designer probiotics, fecal microbiota transplantation, and synthetic biology.

Antibiotics and the Human Gut Microbiome: Dysbioses and Accumulation of Resistances

The human microbiome is overly exposed to antibiotics, due, not only to their medical use, but also to their utilization in farm animals and crops. Microbiome composition can be rapidly altered by exposure to antibiotics, with potential immediate effects on health, for instance through the selection of resistant opportunistic pathogens that can cause acute disease. Microbiome alterations induced by antibiotics can also indirectly affect health in the long-term. The mutualistic microbes in the human body interact with many physiological processes, and participate in the regulation of immune and metabolic homeostasis. Therefore, antibiotic exposure can alter many basic physiological equilibria, promoting long-term disease. In addition, excessive antibiotic use fosters bacterial resistance, and the overly exposed human microbiome has become a significant reservoir of resistance genes, contributing to the increasing difficulty in controlling bacterial infections. Here, the complex relationships between antibiotics and the human microbiome are reviewed, with focus on the intestinal microbiota, addressing (1) the effects of antibiotic use on the composition and function of the gut microbiota, (2) the impact of antibiotic-induced microbiota alterations on immunity, metabolism, and health, and (3) the role of the gut microbiota as a reservoir of antibiotic resistances.

Postnatal Infections and Immunology Affecting Chronic Lung Disease of Prematurity

Premature infants suffer significant respiratory morbidity during infancy with long-term negative consequences on health, quality of life, and health care costs. Enhanced susceptibility to a variety of infections and inflammation play a large role in early and prolonged lung disease following premature birth, although the mechanisms of susceptibility and immune dysregulation are active areas of research. This article reviews aspects of host-pathogen interactions and immune responses that are altered by preterm birth and that impact chronic respiratory morbidity in these children.

Analysis of composition of microbiomes: a novel method for studying microbial composition

Background

Understanding the factors regulating our microbiota is important but requires appropriate statistical methodology. When comparing two or more populations most existing approaches either discount the underlying compositional structure in the microbiome data or use probability models such as the multinomial and Dirichlet-multinomial distributions, which may impose a correlation structure not suitable for microbiome data.

Objective

To develop a methodology that accounts for compositional constraints to reduce false discoveries in detecting differentially abundant taxa at an ecosystem level, while maintaining high statistical power.

Methods

We introduced a novel statistical framework called analysis of composition of microbiomes (ANCOM). ANCOM accounts for the underlying structure in the data and can be used for comparing the composition of microbiomes in two or more populations. ANCOM makes no distributional assumptions and can be implemented in a linear model framework to adjust for covariates as well as model longitudinal data. ANCOM also scales well to compare samples involving thousands of taxa.

Results

We compared the performance of ANCOM to the standard t-test and a recently published methodology called Zero Inflated Gaussian (ZIG) methodology (1) for drawing inferences on the mean taxa abundance in two or more populations. ANCOM controlled the false discovery rate (FDR) at the desired nominal level while also improving power, whereas the t-test and ZIG had inflated FDRs, in some instances as high as 68% for the t-test and 60% for ZIG. We illustrate the performance of ANCOM using two publicly available microbial datasets in the human gut, demonstrating its general applicability to testing hypotheses about compositional differences in microbial communities.

Conclusion

Accounting for compositionality using log-ratio analysis results in significantly improved inference in microbiota survey data.

Maternal prenatal stress is associated with the infant intestinal microbiota

Maternal prenatal stress has been often associated with infant physical development and health, as well as psychological functioning and behavior. However, the mechanisms underlying these relations remain elusive. The goal of the present study was to prospectively investigate the development of the intestinal microbiota as a potential pathway linking maternal prenatal stress and infant health. The development of the infant intestinal microbiota was followed over the first 110 days after birth in a healthy cohort of 56 vaginally born Dutch infants. Additionally, the relation between infant intestinal microbiota and gastrointestinal and allergic symptoms was examined. Results showed that maternal prenatal stress, i.e., either reported stress or elevated basal maternal salivary cortisol concentrations or both, was strongly and persistently associated with the infants' microbiota composition as determined by a phylogenetic microarray. Infants of mothers with high cumulative stress (i.e., high reported stress and high cortisol concentrations) during pregnancy had significantly higher relative abundances of Proteobacterial groups known to contain pathogens (related to Escherichia, Serratia, and Enterobacter), and lower relative abundances of lactic acid bacteria (i.e., Lactobacillus, Lactoccus, Aerococcus) and Bifidobacteria, altogether characteristics of a potentially increased level of inflammation. Furthermore, this aberrant colonization pattern was related to more maternally reported infant gastrointestinal symptoms and allergic reactions. In conclusion, clear links were found between maternal prenatal stress and the infant intestinal microbiota and health. Although causality cannot be concluded, the results suggest a possible mechanism by which maternal prenatal stress influences the offspring development. These results suggest a potential for bacterial interventions to enhance offspring health and development in pregnant women with stress.

Pathogenesis of necrotizing enterocolitis: modeling the innate immune response

Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in premature infants. The pathophysiology is likely secondary to innate immune responses to intestinal microbiota by the premature infant's intestinal tract, leading to inflammation and injury. This review provides an updated summary of the components of the innate immune system involved in NEC pathogenesis. In addition, we evaluate the animal models that have been used to study NEC with regard to the involvement of innate immune factors and histopathological changes as compared to those seen in infants with NEC. Finally, we discuss new approaches to studying NEC, including mathematical models of intestinal injury and the use of humanized mice.

Early development of the gut microbiota and immune health

In recent years, the increase in human microbiome research brought about by the rapidly evolving “omic” technologies has established that the balance among the microbial groups present in the human gut, and their multipronged interactions with the host, are crucial for health. On the other hand, epidemiological and experimental support has also grown for the ‘early programming hypothesis’, according to which factors that act in utero and early in life program the risks for adverse health outcomes later on. The microbiota of the gut develops during infancy, in close interaction with immune development, and with extensive variability across individuals. It follows that the specific process of gut colonization and the microbe-host interactions established in an individual during this period have the potential to represent main determinants of life-long propensity to immune disease. Although much remains to be learnt on the progression of events by which the gut microbiota becomes established and initiates its intimate relationships with the host, and on the long-term repercussions of this process, recent works have advanced significatively in this direction.

Dietary intervention rescues maternal obesity induced behavior deficits and neuroinflammation in offspring

Obesity induces a low-grade inflammatory state and has been associated with behavioral and cognitive alterations. Importantly, maternal environmental insults can adversely impact subsequent offspring behavior and have been linked with neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (AHDH). It is unknown if maternal obesity significantly alters offspring sociability, a key ASD feature, and if altering maternal diet will provide an efficacious intervention paradigm for behavioral deficits. Here we investigated the impact of maternal high fat diet (HFD) and maternal dietary intervention during lactation on offspring behavior and brain inflammation in mice. We found that maternal HFD increased anxiety and decreased sociability in female offspring. Additionally, female offspring from HFD-fed dams also exhibited increased brain IL-1β and TNFα and microglial activation. Importantly, maternal dietary intervention during lactation was sufficient to alleviate social deficits and brain inflammation. Maternal obesity during gestation alone was sufficient to increase hyperactivity in male offspring, a phenotype that was not ameliorated by dietary intervention. These data suggest that maternal HFD acts as a prenatal/perinatal insult that significantly impacts offspring behavior and inflammation and that dietary intervention during lactation may be an easily translatable, efficacious intervention to offset some of these manifestations.

The lung may play a role in the pathogenesis of rheumatoid arthritis

Multiple studies have identified strong associations between the lung and rheumatoid arthritis (RA). Such studies identify a high prevalence of lung disease, both airways and parenchymal disease, in subjects with clinically classifiable RA. It has been suggested that lung disease in RA results from targeting of the lung from circulating autoimmunity or other factors such as medications. However, findings that lung disease, specifically inflammatory airways disease, and lung generation of autoimmunity can be present before the onset of joint symptoms suggest that immune reactions in the lung may be involved in the initial development of RA-related autoimmunity. Herein we review these issues in detail, as well as outline a potential research agenda to understand the natural history of lung involvement in RA and its relation to the overall pathogenesis of RA.

Consumption of acidic water alters the gut microbiome and decreases the risk of diabetes in NOD mice

Infant formula and breastfeeding are environmental factors that influence the incidence of Type 1 Diabetes (T1D) as well as the acidity of newborn diets. To determine if altering the intestinal microbiome is one mechanism through which an acidic liquid plays a role in T1D, we placed non-obese diabetic (NOD)/ShiLtJt mice on neutral (N) or acidified H2O and monitored the impact on microbial composition and diabetes incidence. NOD-N mice showed an increased development of diabetes, while exhibiting a decrease in Firmicutes and an increase in Bacteroidetes, Actinobacteria, and Proteobacteria from as early as 2 weeks of age. NOD-N mice had a decrease in the levels of Foxp3 expression in CD4(+)Foxp3(+) cells, as well as decreased CD4(+)IL17(+) cells, and a lower ratio of IL17/IFNγ CD4+ T-cells. Our data clearly indicates that a change in the acidity of liquids consumed dramatically alters the intestinal microbiome, the presence of protective Th17 and Treg cells, and the incidence of diabetes. This data suggests that early dietary manipulation of intestinal microbiota may be a novel mechanism to delay T1D onset in genetically pre-disposed individuals.

Use of the cockroach antigen model of acute asthma to determine the immunomodulatory role of early exposure to gastrointestinal infection

The increased incidence of asthma over the last 50 years in developed countries has been associated with a decrease in infections acquired early in childhood. These early infections are thought to shape subsequent immune responses. Although there have been multiple clinical associations between gastrointestinal infections and decreased asthma incidence, it has been difficult to move beyond a simple correlation when studying human patients. This section describes an acute asthma model in C57BL/6 mice designed to specifically evaluate the effect of prior gastric Helicobacter colonization and inflammation in a murine model of cockroach allergen-induced asthma.

When and where does inflammation begin in rheumatoid arthritis?

PURPOSE OF REVIEW

The cause of rheumatoid arthritis (RA), as well as the timing and anatomic site at which RA-related autoimmunity is initiated, is currently unknown. An improved understanding of the initial steps in the development of RA would provide insights into disease pathogenesis that could ultimately lead to more effective treatments and/or novel preventive strategies in RA.

RECENT FINDINGS

Systemic inflammation and autoimmunity in RA begin long before the onset of detectable joint inflammation. Emerging data suggest that RA-related autoimmunity may be initiated at a mucosal site years before the onset of joint symptoms. The candidate sites of origin include the oral, lung and gastrointestinal mucosa, as data consistent with this hypothesis have been generated for each location. Individual patients may undergo initiation events at unique sites, but still converge on similar joint findings as the disease process evolves.

SUMMARY

Investigations are needed to determine when and where RA begins, including comprehensive prospective studies of individuals in the preclinical period of RA that can provide insight into the relationship between mucosal inflammation, RA-related autoantibody generation and subsequent joint inflammation in RA.

TGF-β2, a protective intestinal cytokine, is abundant in maternal human milk and human-derived fortifiers but not in donor human milk

OBJECTIVE

This study compared cytokines (in particular transforming growth factor [TGF]-β2) and lactoferrin in maternal human milk (MHM), human-derived milk fortifier (HDMF), and donor human milk (DHM).

MATERIALS AND METHODS

MHM was randomly collected from breastfeeding mothers who had no infectious illness at the time of milk expression. HDMF and DHM were products derived from human milk processed by Holder pasteurization. MHM samples were collected at different times (early/late) and gestations (preterm/term). Lactoferrin was analyzed by western blotting, and cytokines were quantified using commercial enzyme-linked immunosorbent assays. Significance was determined using analysis of variance.

RESULTS

In the 164 samples analyzed, TGF-β2 concentrations in HDMF and preterm MHM (at all collection times) were fivefold higher than in DHM (p<0.05). Early preterm MHM had levels of interleukin (IL)-10 and IL-18, 11-fold higher than DHM (p<0.05). IL-6 in DHM was 0.3% of the content found in MHM. IL-18 was fourfold higher in early MHM versus late MHM regardless of gestational age (p<0.05). Lactoferrin concentration in DHM was 6% of that found in MHM.

CONCLUSIONS

Pasteurization decreases concentrations of most cytokines and lactoferrin in DHM. TGF-β2, a protective intestinal cytokine, has comparable concentrations in HDMF to MHM despite pasteurization.

The role of the microbiome in rheumatic diseases

There is a growing understanding of the mechanisms by which the influence of the microbiota projects beyond sites of primary mucosal occupation to other human body systems. Bacteria present in the intestinal tract exert a profound effect on the host immune system, both locally and at distant sites. The oral cavity has its own characteristic microbiota, which concentrates in periodontal tissues and is in close association with a permeable epithelium. In this review we examine evidence which supports a role for the microbiome in the aetiology of rheumatic disease. We also discuss how changes in the composition of the microbiota, particularly within the gastrointestinal tract, may be affected by genetics, diet, and use of antimicrobial agents. Evidence is presented to support the theory that an altered microbiota is a factor in the initiation and perpetuation of inflammatory diseases, including rheumatoid arthritis (RA), spondyloarthritis (SpA), and inflammatory bowel disease (IBD). Mechanisms through which the microbiota may be involved in the pathogenesis of these diseases include altered epithelial and mucosal permeability, loss of immune tolerance to components of the indigenous microbiota, and trafficking of both activated immune cells and antigenic material to the joints. The potential to manipulate the microbiome, by application of probiotics and faecal microbial transplant (FMT), is now being investigated. Both approaches are in their infancy with regard to management of rheumatic disease but their potential is worthy of consideration, given the need for novel therapeutic approaches, and the emerging recognition of the importance of microbial interactions with human hosts.