Influence of maternal microbiota during pregnancy on infant immunity

Microbiome in Female Reproductive Health: Implications for Fertility and Assisted Reproductive Technologies

The microbiome plays a critical role in the process of conception and the outcomes of pregnancy. Disruptions in microbiome homeostasis in women of reproductive age can lead to various pregnancy complications, which significantly impact maternal and fetal health. Recent studies have associated the microbiome in the female reproductive tract (FRT) with assisted reproductive technology (ART) outcomes, and restoring microbiome balance has been shown to improve fertility in infertile couples. This review provides an overview of the role of the microbiome in female reproductive health, including its implications for pregnancy outcomes and ARTs. Additionally, recent advances in the use of microbial biomarkers as indicators of pregnancy disorders are summarized. A comprehensive understanding of the characteristics of the microbiome before and during pregnancy and its impact on reproductive health will greatly promote maternal and fetal health. Such knowledge can also contribute to the development of ARTs and microbiome-based interventions.

In Utero Exposure to Antibiotics and Risk of Serious Infections in the First Year of Life

INTRODUCTION AND OBJECTIVE

Given the high prevalence of antibiotic prescription during pregnancy in France and previous studies suggesting an increased risk of infection in offspring with such exposures, our study aimed to investigate the association between prenatal exposure to systemic antibiotics and serious infections in full-term infants during their first year of life.

METHODS

We conducted a retrospective population-based cohort study on singleton, full-term liveborn non-immunocompromised infants, using the French National Health Data System (SNDS) between 2012 and 2021. Systemic antibiotic dispensing in ambulatory care settings during pregnancy defined the exposure. Outcomes concerned serious infections (i.e., infections requiring hospitalization) in offspring identified between 3 and 12 months of life, hence excluding infections of maternal origin. Adjusted odds ratios (aORs) were estimated using logistic regression with multivariate models to control for potential confounders.

RESULTS

Of 2,836,630 infants included, 39.6% were prenatally exposed to systemic antibiotics. Infants prenatally exposed to antibiotics had a higher incidence of serious infections compared with unexposed infants {aOR 1.12 [95% confidence interval (95% CI) 1.11-1.13]}. Similar associations were observed according to the timing of exposure during pregnancy, antibiotic class, and site of infections. The strongest association was observed when infants were prenatally exposed to three or more antibiotic courses during pregnancy [aOR 1.21 (95% CI 1.19-1.24)]. Limitations include residual confounders, such as genetic susceptibility to infections and the role of the underlying pathogen agent.

CONCLUSION

Prenatal exposure to systemic antibiotics is very common and is associated with a weak yet significant associations with subsequent serious infectious events during the first year of life. While our study revealed associations, it is important to note that causation cannot be established, given the acknowledged limitations, including potential confounding by indication.

Women health and microbiota: Different aspects of well-being

In this editorial, we comment on the article by Marano et al recently published in the World Journal of Gastroenterology 2023; 29 (45): 5945-5952. We focus on the role of gut microbiota (GM) in women's health, highlighting the need to thoroughly comprehend the sex differences in microbiota. Together, the host and GM support the host's health. The microbiota components consist of viruses, bacteria, fungi, and archaea. This complex is an essential part of the host and is involved in neurological development, metabolic control, immune system dynamics, and host dynamic homeostasis. It has been shown that differences in the GM of males and females can contribute to chronic diseases, such as gastrointestinal, metabolic, neurological, cardiovascular, and respiratory illnesses. These differences can also result in some sex-specific changes in immunity. Every day, research on GM reveals new and more expansive frontiers, offering a wealth of innovative opportunities for preventive and precision medicine.

Composition and interaction of maternal microbiota with immune mediators during pregnancy and their outcome: A narrative review

The connection between maternal microbiota and infant health has been greatly garnered interest for therapeutic purposes. The early resident microbiota perpetually exhibits much more flexibility as compared to that of the adults, and therefore, constant need of understanding the infant as well as maternal microbiota and their implications however has increased. In this review, we focus mainly on the diversity of overall maternal microbiota including the gut, vaginal, colostrum microbiota and how inflammatory markers fluctuate throughout the normal pregnancy as well in pregnancy with complications. The maternal body undergoes a cascade of physiological changes including hormonal, immunological and metabolic events to support the fetal development. These changes at the time of pregnancy have been correlated with alteration in the composition and diversity of maternal microbiota. Along with alteration in microbiome, the levels of circulatory cytokines fluctuate by complex network of inflammation, in order to prevent the fetal allograft throughout the pregnancy. The dynamic relationship of gut microbiota with the host and its immune system allows one to have greater insights of their role in pregnancy and newborn's health. Emerging evidence suggests that the vertical transmission of bacterial community from mother to newborn may begin in-utero which contributes in developing the immune system and infant gut microbiota.

Maternal Prenatal Infections and Biliary Atresia in Offspring

Importance

Investigations into the association of antepartum maternal infections with the pathogenesis of biliary atresia (BA) in human offspring are insufficient.

Objective

To examine the association between prenatal infections in mothers and the development of BA in their offspring.

Design, Setting, and Participants

This population-based case-control study obtained administrative data from the Taiwan National Health Insurance Research Database with linkage to the Taiwan Maternal and Child Health Database, capturing demographic and medical information on nearly all 23 million of the Taiwan population. The cohort comprised 2 905 978 singleton live births among mother-infant dyads between January 1, 2004, and December 31, 2020, in Taiwan. The case group of infants with BA was identified from use of International Classification of Diseases diagnostic codes for BA and subsequent Kasai procedure or liver transplant. The control group was randomly selected from infants without BA, representing approximately 1 in 1000 study population. Data analyses were performed from May 1 to October 31, 2023.

Exposure

Prenatal maternal infections, including intestinal infection, influenza, upper airway infection, pneumonia, soft-tissue infection, and genitourinary tract infection.

Main Outcomes and Measures

The main outcome was exposure to prenatal maternal infections. Inverse probability weighting analysis was performed by building a logistic regression model to estimate the probability of the exposure observed for a particular infant and using the estimated probability as a weight in subsequent analyses. The weighted odds ratio (OR) estimated by logistic regressions was then used to assess the risk of BA in offspring after prenatal maternal infections.

Results

Among the mother-infant dyads included, 447 infants with BA were cases (232 females [51.9%]) and 2912 infants without BA were controls (1514 males [52.0%]). The mean (SD) maternal age at childbirth was 30.7 (4.9) years. Offspring exposed to prenatal intestinal infection (weighted OR, 1.46; 95% CI, 1.17-1.82) and genitourinary tract infection (weighted OR, 1.22; 95% CI, 1.05-1.41) in mothers exhibited a significantly higher risk of BA. Furthermore, maternal intestinal infection (weighted OR, 6.05; 95% CI, 3.80-9.63) and genitourinary tract infection (weighted OR, 1.55; 95% CI, 1.13-2.11) that occurred during the third trimester were associated with an increased risk of BA in offspring.

Conclusions and Relevance

Results of this case-control study indicate an association between prenatal intestinal infection and genitourinary tract infection in mothers and BA occurrence in their offspring. Further studies are warranted to explore the underlying mechanisms of this association.

Bifidobacterium infantis supplementation versus placebo in early life to improve immunity in infants exposed to HIV: a protocol for a randomized trial

INTRODUCTION

Infants who are born from mothers with HIV (infants who are HIV exposed but uninfected; iHEU) are at higher risk of morbidity and display multiple immune alterations compared to infants who are HIV-unexposed (iHU). Easily implementable strategies to improve immunity of iHEU, and possibly subsequent clinical health outcomes, are needed. iHEU have altered gut microbiome composition and bifidobacterial depletion, and relative abundance of Bifidobacterium infantis has been associated with immune ontogeny, including humoral and cellular vaccine responses. Therefore, we will assess microbiological and immunological phenotypes and clinical outcomes in a randomized, double-blinded trial of B. infantis Rosell®-33 versus placebo given during the first month of life in South African iHEU.

METHODS

This is a parallel, randomised, controlled trial. Two-hundred breastfed iHEU will be enrolled from the Khayelitsha Site B Midwife Obstetric Unit in Cape Town, South Africa and 1:1 randomised to receive 8 × 109 CFU B. infantis Rosell®-33 daily or placebo for the first 4 weeks of life, starting on day 1-3 of life. Infants will be followed over 36 weeks with extensive collection of meta-data and samples. Primary outcomes include gut microbiome composition and diversity, intestinal inflammation and microbial translocation and cellular vaccine responses. Additional outcomes include biological (e.g. gut metabolome and T cell phenotypes) and clinical (e.g. growth and morbidity) outcome measures.

DISCUSSION

The results of this trial will provide evidence whether B. infantis supplementation during early life could improve health outcomes for iHEU.

ETHICS AND DISSEMINATION

Approval for this study has been obtained from the ethics committees at the University of Cape Town (HREC Ref 697/2022) and Seattle Children's Research Institute (STUDY00003679).

TRIAL REGISTRATION

Pan African Clinical Trials Registry Identifier: PACTR202301748714019.

CLINICAL

TRIALS

gov: NCT05923333.

PROTOCOL VERSION

Version 1.8, dated 18 July 2023.

Linking Migraine to Gut Dysbiosis and Chronic Non-Communicable Diseases

In the world, migraine is one of the most common causes of disability in adults. To date, there is no a single cause for this disorder, but rather a set of physio-pathogenic triggers in combination with a genetic predisposition. Among the factors related to migraine onset, a crucial role seems to be played by gut dysbiosis. In fact, it has been demonstrated how the intestine is able to modulate the central nervous system activities, through the gut-brain axis, and how gut dysbiosis can influence neurological pathologies, including migraine attacks. In this context, in addition to conventional pharmacological treatments for migraine, attention has been paid to an adjuvant therapeutic strategy based on different nutritional approaches and lifestyle changes able to positively modulate the gut microbiota composition. In fact, the restoration of the balance between the different gut bacterial species, the reconstruction of the gut barrier integrity, and the control of the release of gut-derived inflammatory neuropeptides, obtained through specific nutritional patterns and lifestyle changes, represent a possible beneficial additive therapy for many migraine subtypes. Herein, this review explores the bi-directional correlation between migraine and the main chronic non-communicable diseases, such as diabetes mellitus, arterial hypertension, obesity, cancer, and chronic kidney diseases, whose link is represented by gut dysbiosis.

The Maternal Microbiome and Gestational Diabetes Mellitus: Cause and Effect

Gestational diabetes mellitus (GDM) is a growing public health concern that affects many pregnancies globally. The condition is associated with adverse maternal and neonatal outcomes including gestational hypertension, preeclampsia, placental abruption, preterm birth, stillbirth, and fetal growth restriction. In the long-term, mothers and children have an increased risk of developing metabolic diseases such as type 2 diabetes and cardiovascular disease. Accumulating evidence suggest that alterations in the maternal microbiome may play a role in the pathogenesis of GDM and adverse pregnancy outcomes. This review describes changes in the maternal microbiome during the physiological adaptations of pregnancy, GDM and adverse maternal and neonatal outcomes. Findings from this review highlight the importance of understanding the link between the maternal microbiome and GDM. Furthermore, new therapeutic approaches to prevent or better manage GDM are discussed. Further research and clinical trials are necessary to fully realize the therapeutic potential of the maternal microbiome and translate these findings into clinical practice.

The Impact of Maternal Gut Microbiota during Pregnancy on Fetal Gut-Brain Axis Development and Life-Long Health Outcomes

Gut microbiota plays a critical role in physiological regulation throughout life and is specifically modified to meet the demands of individual life stages and during pregnancy. Maternal gut microbiota is uniquely adapted to the pregnancy demands of the mother and the developing fetus. Both animal studies in pregnant germ-free rodents and human studies have supported a critical association between the composition of maternal microbiota during pregnancy and fetal development. Gut microbiota may also contribute to the development of the fetal gut-brain axis (GBA), which is increasingly recognized for its critical role in health and disease. Most studies consider birth as the time of GBA activation and focus on postnatal GBA development. This review focuses on GBA development during the prenatal period and the impact of maternal gut microbiota on fetal GBA development. It is hypothesized that adaptation of maternal gut microbiota to pregnancy is critical for the GBA prenatal development and maturation of GBA postnatally. Consequently, factors affecting maternal gut microbiota during pregnancy, such as maternal obesity, diet, stress and depression, infection, and medication, also affect fetal GBA development and are critical for GBA activity postnatally. Altered maternal gut microbiota during gestation has been shown to have long-term impact postnatally and multigenerational effects. Thus, understanding the impact of maternal gut microbiota during pregnancy on fetal GBA development is crucial for managing fetal, neonatal, and adult health, and should be included among public health priorities.

Association between prenatal antibiotic exposure and autism spectrum disorder among term births: A population-based cohort study

BACKGROUND

Prenatal antibiotic exposure induces changes in the maternal microbiome, which could influence the development of the infant's microbiome-gut-brain axis.

OBJECTIVES

We assessed whether prenatal antibiotic exposure is associated with an increased risk of autism spectrum disorder (ASD) in offspring born at term.

METHODS

This population-based retrospective cohort study included everyone who delivered a live singleton-term infant in British Columbia, Canada between April 2000 and December 2014. Exposure was defined as filling antibiotic prescriptions during pregnancy. The outcome was an ASD diagnosis from the British Columbia Autism Assessment Network, with a follow-up to December 2016. To examine the association among pregnant individuals treated for the same indication, we studied a sub-cohort diagnosed with urinary tract infections. Cox proportional hazards models were used to estimate unadjusted and adjusted hazard ratios (HR). The analysis was stratified by sex, trimester, cumulative duration of exposure, class of antibiotic, and mode of delivery. We ran a conditional logistic regression of discordant sibling pairs to control for unmeasured environmental and genetic confounding.

RESULTS

Of the 569,953 children included in the cohort, 8729 were diagnosed with ASD (1.5%) and 169,922 were exposed to prenatal antibiotics (29.8%). Prenatal antibiotic exposure was associated with an increased risk of ASD (HR 1.10, 95% confidence interval [CI] 1.05, 1.15), particularly for exposure during the first and second trimesters (HR 1.11, 95% CI 1.04, 1.18 and HR 1.09, 95% CI 1.03, 1.16, respectively), and exposure lasting ≥15 days (HR 1.13, 95% CI 1.04, 1.23). No sex differences were observed. The association was attenuated in the sibling analysis (adjusted odds ratio 1.04, 95% CI 0.92, 1.17).

CONCLUSIONS

Prenatal antibiotic exposure was associated with a small increase in the risk of ASD in offspring. Given the possibility of residual confounding, these results should not influence clinical decisions regarding antibiotic use during pregnancy.

Whole-body microbiota of newborn calves and their response to prenatal vitamin and mineral supplementation

Early life microbial colonization and factors affecting colonization patterns are gaining interest due to recent developments suggesting that early life microbiome may play a role in Developmental Origins of Health and Disease. In cattle, limited information exists on the early microbial colonization of anatomical sites involved in bovine health beyond the gastrointestinal tract. Here, we investigated 1) the initial microbial colonization of seven different anatomical locations in newborn calves and 2) whether these early life microbial communities and 3) serum cytokine profiles are influenced by prenatal vitamin and mineral (VTM) supplementation. Samples were collected from the hoof, liver, lung, nasal cavity, eye, rumen (tissue and fluid), and vagina of beef calves that were born from dams that either received or did not receive VTM supplementation throughout gestation (n = 7/group). Calves were separated from dams immediately after birth and fed commercial colostrum and milk replacer until euthanasia at 30 h post-initial colostrum feeding. The microbiota of all samples was assessed using 16S rRNA gene sequencing and qPCR. Calf serum was subjected to multiplex quantification of 15 bovine cytokines and chemokines. Our results indicated that the hoof, eye, liver, lung, nasal cavity, and vagina of newborn calves were colonized by site-specific microbiota, whose community structure differed from the ruminal-associated communities (0.64 ≥ R² ≥ 0.12, p ≤ 0.003). The ruminal fluid microbial community was the only one that differed by treatment (p < 0.01). However, differences (p < 0.05) by treatment were detected in microbial richness (vagina); diversity (ruminal tissue, fluid, and eye); composition at the phylum and genus level (ruminal tissue, fluid, and vagina); and in total bacterial abundance (eye and vagina). From serum cytokines evaluated, concentration of chemokine IP-10 was greater (p = 0.02) in VTM calves compared to control calves. Overall, our results suggest that upon birth, the whole-body of newborn calves are colonized by relatively rich, diverse, and site-specific bacterial communities. Noticeable differences were observed in ruminal, vaginal, and ocular microbiota of newborn calves in response to prenatal VTM supplementation. These findings can derive future hypotheses regarding the initial microbial colonization of different body sites, and on maternal micronutrient consumption as a factor that may influence early life microbial colonization.

COVID-19 and Pregnancy: An Updated Review about Evidence-Based Therapeutic Strategies

The COVID-19 pandemic posed a significant challenge for clinicians in managing pregnant women, who were at high risk of virus transmission and severe illness. While the WHO declared in May 2023 that COVID-19 is no longer a public health emergency, it emphasized that it remains a global health threat. Despite the success of vaccines, the possibility of new pandemic waves due to viral mutations should be considered. Ongoing assessment of the safety and effectiveness of pharmacological therapies is crucial in clinical practice. This narrative review summarizes the evidence-based therapeutic strategies for pregnant women with COVID-19, considering over three years of pandemic experience. The review discusses the safety and effectiveness of various drug regimens (antivirals, anticoagulants, corticosteroids, immunoglobulins, monoclonal antibodies, and therapeutic gases) and procedures (prone positioning and extracorporeal membrane oxygenation). Drugs with contraindications, inefficacy during pregnancy, or unknown adverse effects were excluded from our evaluation. The aim is to provide healthcare professionals with a comprehensive guide for managing pregnant women with COVID-19 based on lessons learned from the pandemic outbreak.

Prematurely delivering mothers show reductions of lachnospiraceae in their gut microbiomes

BACKGROUND

Preterm birth is the leading cause of perinatal morbidity and mortality. Despite evidence shows that imbalances in the maternal microbiome associates to the risk of preterm birth, the mechanisms underlying the association between a perturbed microbiota and preterm birth remain poorly understood.

METHOD

Applying shotgun metagenomic analysis on 80 gut microbiotas of 43 mothers, we analyzed the taxonomic composition and metabolic function in gut microbial communities between preterm and term mothers.

RESULTS

Gut microbiome of mothers delivering prematurely showed decreased alpha diversity and underwent significant reorganization, especially during pregnancy. SFCA-producing microbiomes, particularly species of Lachnospiraceae, Ruminococcaceae, and Eubacteriaceae, were significantly depleted in preterm mothers. Lachnospiraceae and its species were the main bacteria contributing to species' differences and metabolic pathways.

CONCLUSION

Gut microbiome of mothers delivering prematurely has altered and demonstrates the reduction of Lachnospiraceae.

Impact of the mother's gut microbiota on infant microbiome and brain development

The link between the gut microbiome and health has recently garnered considerable interest in its employment for medicinal purposes. Since the early microbiota exhibits more flexibility compared to that of adults, there is a considerable possibility that altering it will have significant consequences on human development. Like genetics, the human microbiota can be passed from mother to child. This provides information on early microbiota acquisition, future development, and prospective chances for intervention. The succession and acquisition of early-life microbiota, modifications of the maternal microbiota during pregnancy, delivery, and infancy, and new efforts to understand maternal-infant microbiota transmission are discussed in this article. We also examine the shaping of mother-to-infant microbial transmission, and we then explore possible paths for future research to advance our knowledge in this area.

Programming Factors of Neonatal Intestinal Dysbiosis as a Cause of Disease

The intestinal microbiota consists of trillions of bacteria, viruses, and fungi that achieve a perfect symbiosis with the host. They perform immunological, metabolic, and endocrine functions in the body. The microbiota is formed intrauterine. Dysbiosis is a microbiome disorder characterized by an imbalance in the composition of the microbiota, as well as changes in their functional and metabolic activities. The causes of dysbiosis include improper nutrition in pregnant women, hormone therapy, the use of drugs, especially antibiotics, and a lack of exposure to the mother’s vaginal microbiota during natural birth. Changes in the intestinal microbiota are increasingly being identified in various diseases, starting in the early neonatal period into the adult period. Conclusions: In recent years, it has become more and more obvious that the components of the intestinal microbiota are crucial for the proper development of the immune system, and its disruption leads to disease.

Effects of prenatal antibiotic treatment on early infant health: a retrospective study in a rural health facility in Ghana

Background

Infant mortality remains a major developmental challenge in many low-income countries. Epidemiological evidence suggests that infant acquisition of maternal microbiome is essential for programming of immunity and metabolism. As such, irrational maternal antibiotic use may affect infant health.

Objectives

The aim of the study was to determine the effects of prenatal antibiotic use on early postnatal life (90 days) in a low-income community in Ghana.

Methodology

The study was a retrospective study of 412 mother-baby pair medical records in a low-income community in rural Ghana.

Results

During the ninety-day period, the prevalence and relative risk of neonatal sepsis, respiratory disorders, and dermatitis were significantly higher in infants treated prenatally with antibiotics compared to untreated infants. Prenatal antibiotic treatment was not significantly associated with the risk of developing neonatal jaundice and conjunctivitis. However, prenatally antibiotic exposed infants were three times likely to visit the hospital for a non-scheduled/non-review treatment within the first 90 days compared to unexposed babies.

Conclusions

Intrapartum antibiotic treatment is associated with poor early infant health. Rationalizing antibiotic use during pregnancy may contribute to reducing infant mortality.

Liver Microbiome in Healthy Rats: The Hidden Inhabitants of Hepatocytes

The tumor and tissue microbiota of human beings have recently been investigated. Gut permeability is known as a possible resource for the positive detection of tissue bacteria. Herein, we report that microbiota were detected in high abundance in the hepatocytes of healthy rats and that they were shared with the gut microbiota to an extent. We assessed male Sprague Dawley (SD) rats for the 16S ribosomal ribonucleic acid (rRNA) gene. After the rats were sacrificed by blood drainage from the portal vein, we extracted total deoxyribonucleic acid (DNA) from their ileal and colonic contents and liver tissues. The V3–V4 region of the 16S rRNA gene was amplified by polymerase chain reaction (PCR) and sequenced using an Illumina HiSeq 2500 platform. Sequences were assigned taxonomically by the SILVA database. We also detected bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA) in situ using immunofluorescence (IF) and western blotting and the 16S rRNA gene using fluorescent in situ hybridization (FISH). In the livers of six rats, we detected $\mathrm{54,867.50}\pm 6450.03$ effective tags of the 16S rRNA gene and clustered them into 1003 kinds of operational taxonomic units (OTUs; $805.67\pm 70.14$ , 729–893). Rats showed conservation of bacterial richness, abundance, and evenness. LPS and the 16S rRNA gene were detected in the nuclei of hepatocytes. The main function composition of the genomes of annotated bacteria was correlated with metabolism ( $79.92\pm 0.24\%$ ). Gram negativity was about 1.6 times higher than gram positivity. The liver microbiome was shared with both the small and large intestines but showed significantly higher richness and evenness than the gut microbiome, and the β-diversity results showed that the liver microbiome exhibited significantly higher similarity than the small and large intestines ( $P<0.05$ ). Our results suggest that the bacteria in the liver microbiome are hidden intracellular inhabitants in healthy rat livers.

Protective Effect of Vegan Microbiota on Liver Steatosis Is Conveyed by Dietary Fiber: Implications for Fecal Microbiota Transfer Therapy

Fecal microbiota transfer may serve as a therapeutic tool for treating obesity and related disorders but currently, there is no consensus regarding the optimal donor characteristics. We studied how microbiota from vegan donors, who exhibit a low incidence of non-communicable diseases, impact on metabolic effects of an obesogenic diet and the potential role of dietary inulin in mediating these effects. Ex-germ-free animals were colonized with human vegan microbiota and fed a standard or Western-type diet (WD) with or without inulin supplementation. Despite the colonization with vegan microbiota, WD induced excessive weight gain, impaired glucose metabolism, insulin resistance, and liver steatosis. However, supplementation with inulin reversed steatosis and improved glucose homeostasis. In contrast, inulin did not affect WD-induced metabolic changes in non-humanized conventional mice. In vegan microbiota-colonized mice, inulin supplementation resulted in a significant change in gut microbiota composition and its metabolic performance, inducing the shift from proteolytic towards saccharolytic fermentation (decrease of sulfur-containing compounds, increase of SCFA). We found that (i) vegan microbiota alone does not protect against adverse effects of WD; and (ii) supplementation with inulin reversed steatosis and normalized glucose metabolism. This phenomenon is associated with the shift in microbiota composition and accentuation of saccharolytic fermentation at the expense of proteolytic fermentation.

Maternal diet associated with infants' intestinal microbiota mediated by predominant long-chain fatty acid in breast milk

Introduction

Long-chain fatty acids in breast milk are affected by the mother's diet and play an important role in the growth, development, and immune construction of infants. This study aims to explore the correlation between maternal diet, breast milk fatty acids (FAs), and the infant intestinal flora.

Methods

We enrolled 56 paired mothers and their infants; both breast milk samples and infants' fecal samples were collected to determine the long-chain FA content of breast milk by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS), and metagenomic technology was applied to determine the microbial composition of infant feces. The maternal diet was also investigated using a 24-h dietary recall.

Results

The results indicated that the fat contribution rates of edible oils in the maternal diet are significantly positively correlated with the contents of certain long-chain fatty acids (C16:0, C18:1, C16:1, and C22:4) in breast milk, which mainly regulate the abundance of Lacticaseibacillus rhamnosus, Lacticaseibacillus fermentum, and Lacticaseibacillus paracasei in the infant gut. Through KEGG pathway analysis, our data revealed that the long-chain FAs in different groups of breast milk were significantly correlated with the pathways of biotin metabolism, glycerolipid metabolism, and starch and sucrose metabolism.

Discussion

The results of this study suggest a pathway in which the diets of lactating mothers may affect the composition of the infant intestinal microbiota by influencing breast milk FAs and then further regulating infant health.

Risk-Benefit Balance Associated With Obstetric, Neonatal, and Child Outcomes After Metabolic and Bariatric Surgery

Importance

Metabolic and bariatric surgery (MBS) is the most efficient therapeutic option for severe obesity. Most patients who undergo MBS are women of childbearing age. Data in the scientific literature are generally of a low quality due to a lack of well-controlled prospective trials regarding obstetric, neonatal, and child outcomes.

Objective

To assess the risk-benefit balance associated with MBS around obstetric, neonatal, and child outcomes.

Design, Setting, and Participants

The study included 53 813 women on the French nationwide database who underwent an MBS procedure and delivered a child between January 2012 and December 2018. Each women was their own control by comparing pregnancies before and after MBS.

Exposures

The women included were exposed to either gastric bypass or sleeve gastrectomy.

Main Outcomes and Measures

The study team first compared prematurity and birth weights in neonates born before and after maternal MBS with each other. Then they compared the frequencies of all pregnancy and child diagnoses in the first 2 years of life before and after maternal MBS with each other.

Results

A total of 53 813 women (median [IQR] age at surgery, 30 [26-35] years) were included, among 3686 women who had 1 pregnancy both before and after MBS. The study team found a significant increase in the small-for-gestational-age neonate rate after MBS (+4.4%) and a significant decrease in the large-for-gestational-age neonate rate (-12.6%). The study team highlighted that compared with pre-MBS births, after MBS births had fewer occurrences of gestational hypertension (odds ratio [OR], 0.16; 95% CI, 0.10-0.23) and gestational diabetes for the mother (OR, 0.39; 95% CI, 0.34-0.45), as well as fewer birth injuries to the skeleton (OR, 0.27; 95% CI, 0.11-0.60), febrile convulsions (OR, 0.39; 95% CI, 0.21-0.67), viral intestinal infections (OR, 0.56; 95% CI, 0.43-0.71), or carbohydrate metabolism disorders in newborns (OR, 0.54; 95% CI 0.46-0.63), but an elevated respiratory failure rate (OR, 2.42; 95% CI, 1.76-3.36) associated with bronchiolitis.

Conclusions and Relevance

The risk-benefit balance associated with MBS is highly favorable for pregnancies and newborns but may cause an increased risk of respiratory failure associated with bronchiolitis. Further studies are needed to better assess the middle- and long-term benefits and risks associated with MBS.

Microbial composition of egg component and its association with hatchability of laying hens

The internal quality of eggs is critical for human consumption and embryonic development. However, microorganisms inside eggs have not been thoroughly investigated for their roles in determining the egg's internal quality. Here, a total of 21 hens were selected from more than 1,000 chickens based on their hatching results and were divided into high- and low-hatchability groups. Then, we collected 72 eggs from these 21 hens to obtain egg whites and yolks, including 54 fresh eggs and 18 eggs after 12 days of incubation. We characterized the microbial composition of egg yolks and whites, the microbial change along incubation, and differences in microbial abundance between the high- and low-hatchability groups. The results indicated that egg whites are not sterile. Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes were the dominant phyla in egg yolk and white. There was a large difference in the microbial composition between egg whites and yolks, and this difference increased after 12 days of incubation. Egg whites have lower microbial diversity than egg yolks owing to the presence of antibacterial substances such as lysozyme in the egg white. After a 12-day incubation, the microbial diversity decreased in egg whites but increased slightly in egg yolks. Meanwhile, the microbes in egg white can migrate to egg yolk during incubation. Additionally, Genus Muribaculaceae was identified as a biomarker in egg yolks incubated for 12 days and was more often detected in healthy groups. On the contrary, more genus Rothia were found in the fresh egg yolk of the low hatchability groups and was considered to have low virulence. These findings shed light on the composition and differences in microbiota between egg yolks and whites and may open new avenues for studying embryonic development in chickens.

Shared and Non-Shared sIgA-Coated and -Uncoated Bacteria in Intestine of Mother–Infant Pairs

The infant gut microbiota is critical for promoting and maintaining early-life health. The study aimed to analyze the composition of sIgA-coated and sIgA-uncoated bacterial communities at genus level and lactobacilli and bifidobacterial communities at species level in human breast milk (HBM) and infant and maternal feces. Eleven pregnant women were recruited successfully. HBM; infant feces during colostrum, transition, and mature stages; and maternal feces within the mature stage were collected. sIgA-coated and sIgA-uncoated bacteria were separated with magnetic-activated cell sorting. Then, 16S rRNA sequencing, bifidobacterial groEL gene sequencing, and lactobacilli groEL gene sequencing were performed to analyze the bacterial community. PCoA revealed that the compositions of sIgA-coated and sIgA-uncoated bacteria were different among HBM and infant and maternal feces. Higher relative abundance of sIgA-uncoated Bifidobacterium was found in the three lactation stages in infant feces compared to the corresponding HBM, and a higher relative abundance of sIgA-uncoated Faecalibacterium was found in maternal feces compared to HBM and infant feces. For bifidobacterial community, sIgA-coated and sIgA-uncoated B. longum subsp. infantis and B. pseudocatenulatum was dominant in infant feces and maternal feces, respectively. The relative abundance of sIgA-uncoated B. longum subsp. infantis was significantly higher in infant feces compared to that in maternal feces. For the Lactobacillus community, L. paragasseri and L. mucosae were dominant in infant and maternal feces, respectively. HBM and infant and maternal feces showed distinct diversity and composition of both sIgA-coated and sIgA-uncoated bacteria at genus level. Infant and maternal feces showed similar composition of Bifidobacterium at species level. The same Bifidobacterium species could be detected both in sIgA-coated and -uncoated form. This article provided deeper understanding on the microbiota profile in HBM and infant and maternal feces.

The Effects of Probiotics, Prebiotics and Synbiotics in Non-Alcoholic Fat Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH): A Systematic Review

Modifications in the microbiota caused by environmental and genetic reasons can unbalance the intestinal homeostasis, deregulating the host’s metabolism and immune system, intensifying the risk factors for the development and aggravation of non-alcoholic fat liver disease (NAFLD). The use of probiotics, prebiotics and synbiotics have been considered a potential and promising strategy to regulate the gut microbiota and produce beneficial effects in patients with liver conditions. For this reason, this review aimed to evaluate the effectiveness of probiotics, prebiotics, and symbiotics in patients with NAFLD and NASH. Pubmed, Embase, and Cochrane databases were consulted, and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines were followed. The clinical trials used in this study demonstrated that gut microbiota interventions could improve a wide range of markers of inflammation, glycemia, insulin resistance, dyslipidemia, obesity, liver injury (decrease of hepatic enzymes and steatosis and fibrosis). Although microbiota modulators do not play a healing role, they can work as an important adjunct therapy in pathological processes involving NAFLD and its spectrums, either by improving the intestinal barrier or by preventing the formation of toxic metabolites for the liver or by acting on the immune system.

Intersections of the microbiome and early neurodevelopment

Our resident microbes influence nearly all aspects of our biological systems. In particular, the maternal and early life microbiota is uniquely positioned to influence the development of the nervous system, and alterations to the gut microbiota, or dysbiosis, during this critical time in early life can have long-lasting negative effects on health. The question of how the maternal and early life microbiota shapes neurodevelopment is the topic of numerous investigations. Here, we discuss two possible, but not necessarily independent, hypotheses: (1) the maternal microbiota during pregnancy regulates the metabolites that are important for fetal development, (2) maternal microbiota seeded to offspring at birth and early postnatal days programs offspring immune and brain development, and regulates key molecules for postnatal brain development. In this chapter, we provide an overview of the impact of the microbiota on brain and behavior, introduce the maternal gut and vaginal microbiome during pregnancy, and discuss current understandings of microbiome in the context of developmental origins of health and disease. We consider novel translational insights that harness the multitude of microbes and microbial metabolites for prevention or treatment of neurological disorders.

Pregnancy as a Fundamental Determinant of Child Health: a Review

PURPOSE OF REVIEW

Maternal conditions and exposures during pregnancy including over- and undernutrition are associated with poor childbirth outcomes, growth, development and chronic childhood diseases. We examined contemporary pregnancy-related determinants of child health.

RECENT FINDINGS

While maternal undernutrition remains a major contributor to low birth weight, maternal obesity affects foetal growth, birth weight, survival and is associated with childhood obesity, asthma and autistic spectrum disorders. Emerging evidence suggests that epigenetic changes, the prenatal microbiome and maternal immune activation (MIA), a neuroinflammatory process induced by diet and other exposures cause foetal programming resulting in these chronic childhood diseases. Maternal diet is potentially a modifiable risk factor for controlling low birth weight, obesity and chronic disease in childhood. Further studies are warranted to refine guidance on dietary restriction and physical activity during pregnancy and determine how MIA and prenatal microbiota can be applied to control childhood diseases arising from programming.

Nutrition and Immunity in Perinatal Hypoxic-Ischemic Injury

Perinatal hypoxia ischaemia (PHI), acute and chronic, may be associated with considerable adverse outcomes in the foetus and neonate. The molecular and cellular mechanisms of injury and repair associated with PHI in the perinate are not completely understood. Increasing evidence is mounting for the role of nutrients and bioactive food components in immune development, function and repair in PHI. In this review, we explore current concepts around the neonatal immune response to PHI with a specific emphasis on the impact of nutrition in the mother, foetus and neonate.

Brief Hydromorphone Exposure During Pregnancy Sufficient to Induce Maternal and Neonatal Microbial Dysbiosis

Prenatal opioid exposure is associated with significantly adverse medical, developmental, and behavioral outcomes in offspring, though the underlying mechanisms driving these impairments are still unclear. Accumulating evidence implicates gut microbial dysbiosis as a potential modulator of these adverse effects. However, how opioid exposure during pregnancy alters the maternal and neonatal microbiome remain to be elucidated. Here, we utilize a murine model of brief hydromorphone exposure during pregnancy (gestation day 11-13; i.p.; 10 mg/kg) to examine its impact on the maternal and neonatal microbiome. Fecal samples were collected at various timepoints in dams (4 days post hydromorphone exposure, birth, and weaning) and offspring (2, 3, and 5 weeks) to interrogate longitudinal changes in the microbiome. Stomach contents at 2 weeks were also collected as a surrogate for breastmilk and microbial analysis was performed using 16S rRNA sequencing. Alongside alterations in the maternal gut microbial composition, offspring gut microbiota exhibited distinct communities at 2 and 3 weeks. Furthermore, functional profiling of microbial communities revealed significant differences in microbial community-level phenotypes gram-negative, gram-positive, and potentially pathogenic in maternal and/or neonatal hydromorphone exposed groups compared with controls. We also observed differences in stomach microbiota in opioid-exposed vs non-exposed offspring, which suggests breast milk may also play a role in shaping the development of the neonatal gut microbiota. Together, we provide evidence of maternal and neonatal microbial dysbiosis provoked even with brief hydromorphone exposure during pregnancy.

Food Protein-Induced Allergic Proctocolitis: The Effect of Maternal Diet During Pregnancy and Breastfeeding in a Mediterranean Population

Background

The aim of the current investigation was to explore the association of food protein-induced allergic proctocolitis (FPIAP) with the maternal diet during pregnancy and breastfeeding in Greek infants.

Methods

A multicenter retrospective case-control study was conducted in 6 regions in Greece, with 96 mothers of infants with and 141 mothers of infants without a history of FPIAP. Maternal dietary habits during pregnancy and breastfeeding were evaluated with the following validated questionnaires: (a) The Mediterranean Diet Score and (b) The Mediterranean Oriented Culture-Specific Semi-Quantitative Food Frequency Questionnaire.

Results

FPIAP was associated with cow's milk (83.6%), egg (7.3%), wheat (6.4%), and beef (6.4%) in the maternal diet. Adherence to Mediterranean Diet was similar among the mothers. Mothers of FPIAP infants consumed more vegetables. Elastic net prediction models showed that, in this Mediterranean population, increased consumption during pregnancy and lactation of common allergens, whole grain products, homemade food, fish and shellfish, and fruits was associated with a decreased risk of FPIAP. Conversely, a high intake of vegetables, sugar and total fat, and non-stick/grilled cooking, were associated with increased risk of FPIAP, as was a high intake of salt and white flour during lactation only.

Conclusions

Components of a maternal Mediterranean Diet may protect against FPIAP when traditional cooking methods are adopted and fish, fruit, and whole wheat products are consumed frequently during pregnancy and breastfeeding.

Microorganisms in the reproductive system and probiotic's regulatory effects on reproductive health

The presence of microbial communities in the reproductive tract has been revealed, and this resident microbiota is involved in the maintenance of health. Intentional modulation via probiotics has been proposed as a possible strategy to enhance reproductive health and reduce the risk of diseases. The male seminal microbiota has been suggested as an important factor that influences a couple’s health, pregnancy outcomes, and offspring health. Probiotics have been reported to play a role in male fertility and to affect the health of mothers and offspring. While the female reproductive microbiota is more complicated and has been identified in both the upper and lower reproductive systems, they together contribute to health maintenance. Probiotics have shown regulatory effects on the female reproductive tract, thereby contributing to homeostasis of the tract and influencing the health of offspring. Further, through transmission of bacteria or through other indirect mechanisms, the parent’s reproductive microbiota and probiotic intervention influence infant gut colonization and immunity development, with potential health consequences. In vitro and in vivo studies have explored the mechanisms underlying the benefits of probiotic administration and intervention, and an array of positive results, such as modulation of microbiota composition, regulation of metabolism, promotion of the epithelial barrier, and improvement of immune function, have been observed. Herein, we review the state of the art in reproductive system microbiota and its role in health and reproduction, as well as the beneficial effects of probiotics on reproductive health and their contributions to the prevention of associated diseases.

Maternal Influences and Intervention Strategies on the Development of Food Allergy in Offspring

Food allergies and other immune-mediated diseases have become serious health concerns amongst infants and children in developed and developing countries. The absence of available cures limits disease management to allergen avoidance and symptomatic treatments. Research has suggested that the presence of maternal food allergies may expose the offspring to genetic predisposition, making them more susceptible to allergen sensitization. The following review has focused on epidemiologic studies regarding maternal influences of proneness to develop food allergy in offspring. The search strategy was "food allergy OR maternal effects OR offspring OR prevention". A systematically search from PubMed/MEDLINE, Science Direct and Google Scholar was conducted. Specifically, it discussed the effects of maternal immunity, microbiota, breastfeeding, genotype and allergy exposure on the development of food allergy in offspring. In addition, several commonly utilized prenatal and postpartum strategies to reduce food allergy proneness were presented, including early diagnosis of high-risk infants and various dietary interventions.

Novel Potential Biomarkers for Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is the main risk factor for vision-threatening disease in premature infants with low birth weight. An accumulating number of independent studies have focused on ROP pathogenesis and have demonstrated that laser photocoagulation therapy and/or anti-VEGF treatment are effective. However, early diagnosis of ROP is still critical. At present, the main method of ROP screening is based on binocular indirect ophthalmoscopy. However, the judgment of whether ROP occurs and whether treatment is necessary depends largely on ophthalmologists with a great deal of experience. Therefore, it is essential to develop a simple, accurate and effective diagnostic method. This review describes recent findings on novel biomarkers for the prediction, diagnosis and prognosis of ROP patients. The novel biomarkers were separated into the following categories: metabolites, cytokines and growth factors, non-coding RNAs, iconography, gut microbiota, oxidative stress biomarkers, and others. Biomarkers with high sensitivity and specificity are urgently needed for the clinical applications of ROP. In addition, using non-invasive or minimally invasive methods to obtain samples is also important. Our review provides an overview of potential biomarkers of ROP.

Does the Fetus Limit Antibiotic Treatment in Pregnant Patients with COVID-19?

During pregnancy, there is a state of immune tolerance that predisposes them to viral infection, causing maternal-fetal vulnerability to the adverse effects of COVID-19. Bacterial coinfections significantly increase the mortality rate for COVID-19. However, it is known that all drugs, including antibiotics, will enter the fetal circulation in a variable degree despite the role of the placenta as a protective barrier and can cause teratogenesis or other malformations depending on the timing of exposure to the drug. Also, it is important to consider the impact of the indiscriminate use of antibiotics during pregnancy can alter both the maternal and fetal-neonatal microbiota, generating future repercussions in both. In the present study, the literature for treating bacterial coinfections in pregnant women with COVID-19 is reviewed. In turn, we present the findings in 50 pregnant women hospitalized diagnosed with SARS-CoV-2 without previous treatment with antibiotics; moreover, a bacteriological culture of sample types was performed. Seven pregnant women had coinfection with Staphylococcus haemolyticus, Staphylococcus epidermidis, Streptococcus agalactiae, Escherichia coli ESBL +, biotype 1 and 2, Acinetobacter jahnsonii, Enterococcus faecium, and Clostridium difficile. When performing the antibiogram, resistance to multiple drugs was found, such as macrolides, aminoglycosides, sulfa, dihydrofolate reductase inhibitors, beta-lactams, etc. The purpose of this study was to generate more scientific evidence on the better use of antibiotics in these patients. Because of this, it is important to perform an antibiogram to prevent abuse of empirical antibiotic treatment with antibiotics in pregnant women diagnosed with SARS-CoV-2.

Contribution of Gut Microbiota to Immune Tolerance in Infants

The prevalence of food allergy has increased in recent years, especially among the pediatric population. Differences in the gut microbiota composition between children with FA and healthy children have brought this topic into the spotlight as a possible explanation for the increase in FA. The gut microbiota characteristics are acquired through environmental interactions starting early in life, such as type of delivery during birth and breastfeeding. The microbiota features may be shaped by a plethora of immunomodulatory mechanisms, including a predominant role of Tregs and the transcription factor FOXP3. Additionally, a pivotal role has been given to vitamin A and butyrate, the main anti-inflammatory metabolite. These observations have led to the study and development of therapies oriented to modifying the microbiota and metabolite profiles, such as the use of pre- and probiotics and the determination of their capacity to induce tolerance to allergens that are relevant to FA. To date, evidence supporting these approaches in humans is scarce and inconclusive. Larger cohorts and dose-titration studies are mandatory to evaluate whether the observed changes in gut microbiota composition reflect medical recovery and increased tolerance in pediatric patients with FA. In this article, we discuss the establishment of the microbiota, the immunological mechanisms that regulate the microbiota of children with food allergies, and the evidence in research focused on its regulation as a means to achieve tolerance to food allergens.

Establishment of tissue-resident immune populations in the fetus

The immune system establishes during the prenatal period from distinct waves of stem and progenitor cells and continuously adapts to the needs and challenges of early postnatal and adult life. Fetal immune development not only lays the foundation for postnatal immunity but establishes functional populations of tissue-resident immune cells that are instrumental for fetal immune responses amidst organ growth and maturation. This review aims to discuss current knowledge about the development and function of tissue-resident immune populations during fetal life, focusing on the brain, lung, and gastrointestinal tract as sites with distinct developmental trajectories. While recent progress using system-level approaches has shed light on the fetal immune landscape, further work is required to describe precise roles of prenatal immune populations and their migration and adaptation to respective organ environments. Defining points of prenatal susceptibility to environmental challenges will support the search for potential therapeutic targets to positively impact postnatal health.

The relationship between human milk, a functional nutrient, and microbiota

The intestinal microbiota begins to take shape in the mother's womb, changes depending on many factors. It is known that the intestinal microbiota has an important role in the maturation of the immune system, also in the prevention of diseases that occur in newborn, childhood, adulthood. Nutrition is the main factor on the development of microbiota in infants after birth. The microbiota compositions of breastfed infants are different from formula-fed infants. Breast milk oligosaccharides play an important role in the development of infants' microbiota. The higher number of Bifidobacterium species and lower α and β diversity in breastfed infants are considered protective. A dysbiosis occurring in the microbiota can cause adverse effects on health. Human milk oligosaccharides also have protective effects on the microbiota. These protective effects are to promote the growth of intestinal microbiota, prevent the adhesion of viruses to the colon, promote the growth of Bifidobacterium with its prebiotic effect. Short-chain fatty acids resulting from their digestion, also have protective effects. Another component that shapes the gut microbiota is HM glycoproteins. The aim of this study is to examine the effect of breast milk on the development of microbiota, to present the results by scanning the literature.

Inherent maternal type 2 immunity: Consequences for maternal and offspring health

An inherent elevation in type 2 immunity is a feature of maternal and offspring immune systems. This has diverse implications for maternal and offspring biology including influencing success of pregnancy, offspring immune development and maternal and offspring ability to control infection and diseases such as allergies. In this review we provide a broad insight into how this immunological feature of pregnancy and early life impacts both maternal and offspring biology. We also suggest how understanding of this axis of immune influence is and may be utilised to improve maternal and offspring health.

Prevention of Atopic Dermatitis in Mice by Lactobacillus Reuteri Fn041 Through Induction of Regulatory T Cells and Modulation of the Gut Microbiota

SCOPE

The development of atopic dermatitis (AD) in infants is closely related to the lagging development of intestinal microbiota, including that inoculated by breast milk bacteria, and immune development. Lactobacillus reuteri Fn041 is a secretory immunoglobulin A (sIgA) -coated bacterium derived from human milk.

METHODS AND RESULTS

We intervened with L. reuteri Fn041 in maternal and offspring BALB/C mice during late gestation and lactation and after weaning of the pups, respectively. AD was then induced with MC903. L. reuteri Fn041 significantly suppressed AD symptoms such as skin swelling, mast cell and eosinophil infiltration. This effect was attributed to the regulation of the systemic Th1 and Th2 cytokine ratios and the promotion of CD4⁺ CD25⁺ Foxp3⁺ regulatory T cell proliferation in mesenteric lymph nodes. It is also associated with the regulation of intestinal microbiota, particularly promoting Lactobacillus and Akkermansia.

CONCLUSIONS

Our study strengthens the understanding that breast milk-derived sIgA coated potential probiotics are involved in the development of infant intestinal microbiota, thus promoting immune development and preventing allergic diseases, and expanding the knowledge of breast milk sIgA and bacterial interactions on infant immune development. This article is protected by copyright. All rights reserved.

Insights into the role of vaginal microbiome in women's health

The vaginal microbiome is a complex and dynamic microecosystem that fluctuates continually throughout a woman's life. Lactobacillus, a bacterium that possesses antibacterial properties dominates a healthy vaginal microbiome. Bacterial vaginosis is the most common vaginal disorder that has been linked with the dysbiosis of normal vaginal microbiota. Despite the importance of vaginal microbiome, little is known about functions it performs especially, how it helps in protecting the female reproductive tract. This knowledge gap is a significant impediment to the development of effective and feasible clinical treatments that might be required to improve women's health. Thus, a deeper understanding of the functional aspects and not just the composition of vaginal microbiome may aid in improving the diagnostics and treatment strategies. Recent advancement in molecular methods and computational biology have allowed researchers to acquire more knowledge about the vaginal microbiome. The use of metagenomics (culture-independent high-throughput technology) and bioinformatics tools have improved our understanding of the vaginal microbiome. In this review, we have attempted to explore the factors that may alter normal vaginal microbiota homeostasis such as age, sexual behavior, ethnicity, and hygiene, and so forth. We also discuss the role of probiotics in restoring healthy vaginal microbiome.

The significance of maternal asymptomatic bacteriuria during pregnancy on long-term offspring infectious hospitalizations

Asymptomatic bacteriuria (ASB) is a well-acknowledged infectious entity during pregnancy; yet its long-term implications are not well investigated. The present study aimed to test the association between maternal ASB during pregnancy and long-term offspring infectious hospitalizations. A population-based cohort analysis was conducted, comparing the incidence of long-term infectious-related hospitalizations of offspring born to mothers who were diagnosed with ASB during pregnancy, and those who did not have ASB. The study was conducted at a tertiary medical center and included all singleton deliveries between the years 1991 and 2014. Infectious morbidities were based on a predefined set of International Classification of Disease-9 codes. A Kaplan-Meier survival curve compared cumulative infectious hospitalization incidence between the groups, and a Cox regression model was used to adjust for confounding variables. During the study period, 212,984 deliveries met inclusion criteria. Of them, 5378 (2.5%) were diagnosed with ASB. As compared to offspring of non-ASB mothers, total long-term infectious hospitalizations were significantly higher among children to mothers who were diagnosed with ASB (13.1% vs. 11.1%, OR = 1.2, 95% CI 1.11-1.30, P ≤ 0.001). Likewise, a Kaplan-Meier curve demonstrated higher cumulative incidence of infectious hospitalizations among children born to mothers with ASB (log rank, P = 0.006). In the Cox regression model, while controlling for maternal age, diabetes mellitus, ethnicity, hypertensive disorders, and gestational age, maternal ASB was noted as an independent risk factor for long-term infectious morbidity in the offspring (adjusted HR = 1.1, 95% CI 1.01-1.17, P = 0.042). ASB during pregnancy increases offspring susceptibility to long-term infectious hospitalizations.

The gut-cardiovascular connection: new era for cardiovascular therapy

Our gut microbiome is constituted by trillions of microorganisms including bacteria, archaea and eukaryotic microbes. Nowadays, gut microbiome has been gradually recognized as a new organ system that systemically and biochemically interact with the host. Accumulating evidence suggests that the imbalanced gut microbiome contributes to the dysregulation of immune system and the disruption of cardiovascular homeostasis. Specific microbiome profiles and altered intestinal permeability are often observed in the pathophysiology of cardiovascular diseases. Gut-derived metabolites, toxins, peptides and immune cell-derived cytokines play pivotal roles in the induction of inflammation and the pathogenesis of dysfunction of heart and vasculature. Impaired crosstalk between gut microbiome and multiple organ systems, such as gut-vascular, heart-gut, gut-liver and brain-gut axes, are associated with higher cardiovascular risks. Medications and strategies that restore healthy gut microbiome might therefore represent novel therapeutic options to lower the incidence of cardiovascular and metabolic disorders.

Insights into epidemiologic assessments of the microbiome and challenges in identifying microbiome relationships with adverse pregnancy outcomes

Purpose of review

We describe different methods for microbiome assessment and analysis and highlight some of the challenges of using omics data in epidemiologic studies of adverse pregnancy outcomes.

Recent findings

Human microbiomes are dynamic and vary by ancestry and geography. The composition and dynamics of the vaginal microbiome has been associated with risk of preterm birth.

Summary

There are several different methods for characterizing the microbiome. Choice of method depends on the research question and resources available. Added to known challenges of conducting and analyzing epidemiologic studies are the unique challenges associated with microbiome detection and analysis. The resulting omics assessments of human microbial communities have great potential to identify prognostics, diagnostics and potentially therapeutics for adverse pregnancy outcomes.

Molecular Mechanism of Microbiota Metabolites in Preterm Birth: Pathological and Therapeutic Insights

Preterm birth (PTB) refers to the birth of infants before 37 weeks of gestation and is a challenging issue worldwide. Evidence reveals that PTB is a multifactorial dysregulation mediated by a complex molecular mechanism. Thus, a better understanding of the complex molecular mechanisms underlying PTB is a prerequisite to explore effective therapeutic approaches. During early pregnancy, various physiological and metabolic changes occur as a result of endocrine and immune metabolism. The microbiota controls the physiological and metabolic mechanism of the host homeostasis, and dysbiosis of maternal microbial homeostasis dysregulates the mechanistic of fetal developmental processes and directly affects the birth outcome. Accumulating evidence indicates that metabolic dysregulation in the maternal or fetal membranes stimulates the inflammatory cytokines, which may positively progress the PTB. Although labour is regarded as an inflammatory process, it is still unclear how microbial dysbiosis could regulate the molecular mechanism of PTB. In this review based on recent research, we focused on both the pathological and therapeutic contribution of microbiota-generated metabolites to PTB and the possible molecular mechanisms.

The role of CD71+ erythroid cells in the regulation of the immune response

Complex regulation of the immune response is necessary to support effective defense of an organism against hostile invaders and to maintain tolerance to harmless microorganisms and autoantigens. Recent studies revealed previously unappreciated roles of CD71⁺ erythroid cells (CECs) in regulation of the immune response. CECs physiologically reside in the bone marrow where erythropoiesis takes place. Under stress conditions, CECs are enriched in some organs outside of the bone marrow as a result of extramedullary erythropoiesis. However, the role of CECs goes well beyond the production of erythrocytes. In neonates, increased numbers of CECs contribute to their vulnerability to infectious diseases. On the other side, neonatal CECs suppress activation of immune cells in response to abrupt colonization with commensal microorganisms after delivery. CECs are also enriched in the peripheral blood of pregnant women as well as in the placenta and are responsible for the regulation of feto-maternal tolerance. In patients with cancer, anemia leads to increased frequency of CECs in the peripheral blood contributing to diminished antiviral and antibacterial immunity, as well as to accelerated cancer progression. Moreover, recent studies revealed the role of CECs in HIV and SARS-CoV-2 infections. CECs use a full arsenal of mechanisms to regulate immune response. These cells suppress proinflammatory responses of myeloid cells and T-cell proliferation by the depletion of ʟ-arginine by arginase. Moreover, CECs produce reactive oxygen species to decrease T-cell proliferation. CECs also secrete cytokines, including transforming growth factor β (TGF-β), which promotes T-cell differentiation into regulatory T-cells. Here, we comprehensively describe the role of CECs in orchestrating immune response and indicate some therapeutic approaches that might be used to regulate their effector functions in the treatment of human conditions.

Association and Occurrence of Bifidobacterial Phylotypes Between Breast Milk and Fecal Microbiomes in Mother-Infant Dyads During the First 2 Years of Life

Breast milk acts as an intermediary for the transfer of functionally important commensal bacteria from mother to infant, especially for Bifidobacterium that can colonize the infant gut. However, the vast majority of rRNA amplicon-based studies reported the conspicuous intercohort and interindividual variation for the prevalence of Bifidobacterium in breast milk. In order to elucidate whether Bifidobacterium phylotypes persistently co-occured at the species or strain level in mother–breast milk–infant triads, we analyzed collectively the next-generation sequencing (NGS) datasets of bacterial 16S rRNA gene and the Bifidobacterium-specific groEL gene from maternal feces, breast milk, and infant feces in a small yet very homogeneous cohort of 25 healthy Uyghur mother–infant pairs (lactation for 7–720 days) in Kashgar, Xinjiang, China. Overall, 16S rRNA gene analysis showed that microbiome in the newborn gut was closer to that of breast milk in the first 4 months of lactation, and subsequently showed an obvious trend of adulthood at 6–12 months. Based on the BLAST accurate taxonomic result of the representative sequences of all ASVs (amplicon sequencing variants), only three sets of ASVs could be clearly assigned into Bifidobacterium species, whereas the remaining eight sets of ASVs corresponded to four indefinite Bifidobacterium species group. By contrast, the groEL gene dataset was partitioned into 376 ASVs, at least belonging to 13 well-known Bifidobacterium species or subspecies, of which 15 ASVs, annotated to seven well-known Bifidobacterium species or subspecies, showed triadic synchronism in most 23 mother–infant pairs tested. However, several other rare bifidobacterial phylotypes, which were frequently encountered in animals, were found to display no correspondence of the presence between the three ecosystems of mother–infant pairs. Our test results were obviously to support the hypothesis that breast milk acts as an intermediary for the transfer of probiotic commensal bacteria from mother to infant, especially for endosymbiotic Bifidobacterium that can colonize the infant gut. Some oxygen-insensitive exogenous Bifidobacterium phylotypes with a cosmopolitan lifestyle may be indirectly transferred to breast milk and the infant’s intestinal tract through environmental contamination. Thus, the groEL gene proved to be a very effective target for the depth resolution of Bifidobacterium community by high-throughput sequencing technologies.

Impacts of ceftriaxone exposure during pregnancy on maternal gut and placental microbiota and its influence on maternal and offspring immunity in mice

This study aimed to investigate the association between microbiota found in the maternal gut and placenta, and whether ceftriaxone exposure during pregnancy could alter these microbiota, and consequently affect the immunity of the mothers and their offspring. The microbiota in the feces and placenta of the dams were comprehensively analyzed using16S rRNA sequencing. Furthermore, viable bacteria in the placentas and blood of pups were also isolated by plate cultivation then taxonomically identified in detail by clone sequencing. Serum cytokines collected from dams and pups were quantitatively profiled using Luminex. The spleen organ index of dams was significantly lower and the offspring serum interleukin-6 levels were significantly higher in ceftriaxone-treated mice compared with the control group. The maternal fecal microbiota community was drastically altered in ceftriaxone-treated mice with significantly decreased diversity, depletion of Bacteroidetes and the blooming of Tenericutes. However, the placenta microbiota was dominated by Proteobacteria especially characteristically by Ralstonia, which was distinct from the maternal gut microbiota, regardless of whether ceftriaxone treatment or not. Viable bacteria have been found in placenta and blood cultures. These results indicated that ceftriaxone exposure in pregnancy could dramatically alter maternal intestinal microbiota, which affected the immunity of the mothers and their offspring at least partly, characteristically by enhanced pro-inflammatory responses. This study also indicated that the placenta might harbor its own microbes and the microbes were distinct from maternal gut microbiota, which may not be affected by oral administration of ceftriaxone during pregnancy.