When a Neonate Is Born, So Is a Microbiota

Exploring Maternal Diet-Epigenetic-Gut Microbiome Crosstalk as an Intervention Strategy to Counter Early Obesity Programming

Alterations in a mother's metabolism and endocrine system, due to unbalanced nutrition, may increase the risk of both metabolic and non-metabolic disorders in the offspring's childhood and adulthood. The risk of obesity in the offspring can be determined by the interplay between maternal nutrition and lifestyle, intrauterine environment, epigenetic modifications, and early postnatal factors. Several studies have indicated that the fetal bowel begins to colonize before birth and that, during birth and nursing, the gut microbiota continues to change. The mother's gut microbiota is primarily transferred to the fetus through maternal nutrition and the environment. In this way, it is able to impact the establishment of the early fetal and neonatal microbiome, resulting in epigenetic signatures that can possibly predispose the offspring to the development of obesity in later life. However, antioxidants and exercise in the mother have been shown to improve the offspring's metabolism, with improvements in leptin, triglycerides, adiponectin, and insulin resistance, as well as in the fetal birth weight through epigenetic mechanisms. Therefore, in this extensive literature review, we aimed to investigate the relationship between maternal diet, epigenetics, and gut microbiota in order to expand on current knowledge and identify novel potential preventative strategies for lowering the risk of obesity in children and adults.

Fusobacterium nucleatum: An Overview of Evidence, Demi-Decadal Trends, and Its Role in Adverse Pregnancy Outcomes and Various Gynecological Diseases, including Cancers

Gynecological and obstetric infectious diseases are crucial to women's health. There is growing evidence that links the presence of Fusobacterium nucleatum (F. nucleatum), an anaerobic oral commensal and potential periodontal pathogen, to the development and progression of various human diseases, including cancers. While the role of this opportunistic oral pathogen has been extensively studied in colorectal cancer in recent years, research on its epidemiological evidence and mechanistic link to gynecological diseases (GDs) is still ongoing. Thus, the present review, which is the first of its kind, aims to undertake a comprehensive and critical reappraisal of F. nucleatum, including the genetics and mechanistic role in promoting adverse pregnancy outcomes (APOs) and various GDs, including cancers. Additionally, this review discusses new conceptual advances that link the immunomodulatory role of F. nucleatum to the development and progression of breast, ovarian, endometrial, and cervical carcinomas through the activation of various direct and indirect signaling pathways. However, further studies are needed to explore and elucidate the highly dynamic process of host-F. nucleatum interactions and discover new pathways, which will pave the way for the development of better preventive and therapeutic strategies against this pathobiont.

Mind over Microbes: Investigating the Interplay between Lifestyle Factors, Gut Microbiota, and Brain Health

BACKGROUND

The gut microbiota (GM) of the human body comprises several species of microorganisms. This microorganism plays a significant role in the physiological and pathophysiological processes of various human diseases.

METHODS

The literature review includes studies that describe causative factors that influence GM. The GM is sensitive to various factors like circadian rhythms, environmental agents, physical activity, nutrition, and hygiene that together impact the functioning and composition of the gut microbiome. This affects the health of the host, including the psycho-neural aspects, due to the interconnectivity between the brain and the gut. Hence, this paper examines the relationship of GM with neurodegenerative disorders in the context of these aforesaid factors.

CONCLUSION

Future studies that identify the regulatory pathways associated with gut microbes can provide a causal link between brain degeneration and the gut at a molecular level. Together, this review could be helpful in designing preventive and treatment strategies aimed at GM, so that neurodegenerative diseases can be treated.

Rural Versus Urban Mothers' Microbiome Difference and Its Effect on Neonates: A Systematic Review

The growth and development of microorganisms are stimulated by external stimuli. Urbanization has changed the macroenvironment and individual microenvironmental factors such as smoking, alcohol, and diet, which can alter the microbiota and influence disease in the mother and child. However, the microbiome difference between rural and urban mothers and its effect on neonates have received little attention, as per sources; we have not found any systematic review. This review determined the microbiome difference between rural and urban mothers and its effect on neonates. Five studies selected based on inclusion/exclusion criteria were retrieved from PubMed, Scopus, and Embase databases, and evidence-based comparisons were made to establish the microbiome difference in rural and urban mothers and its effect on neonates. The study findings indicate that microbiome development in newborns is hindered by urbanization. Infants born to urban mothers have reduced microbial diversity, thereby having decreased protective immunity.

The source of microbial transmission influences niche colonization and microbiome development

Early life microbial colonizers shape and support the immature vertebrate immune system. Microbial colonization relies on the vertical route via parental provisioning and the horizontal route via environmental contribution. Vertical transmission is mostly a maternal trait making it hard to determine the source of microbial colonization in order to gain insight into the establishment of the microbial community during crucial development stages. The evolution of unique male pregnancy in pipefishes and seahorses enables the disentanglement of both horizontal and vertical transmission, but also facilitates the differentiation of maternal versus paternal provisioning ranging from egg development, to male pregnancy and early juvenile development. Using 16S rRNA amplicon sequencing and source-tracker analyses, we revealed how the distinct origins of transmission (maternal, paternal and horizontal) shaped the juvenile internal and external microbiome establishment in the broad-nosed pipefish Syngnathus typhle. Our data suggest that transovarial maternal microbial contribution influences the establishment of the juvenile gut microbiome whereas paternal provisioning mainly shapes the juvenile external microbiome. The identification of juvenile key microbes reveals crucial temporal shifts in microbial development and enhances our understanding of microbial transmission routes, colonization dynamics and their impact on lifestyle evolution.

Maternal transmission of bacterial microbiota during embryonic development in a viviparous lizard

IMPORTANCE

We investigated the presence and diversity of bacteria in the embryos of the viviparous lizard Sceloporus grammicus and their amniotic environment. We compared this diversity to that found in the maternal intestine, mouth, and cloaca. We detected bacterial DNA in the embryos, albeit with a lower bacterial species diversity than found in maternal tissues. Most of the bacterial species detected in the embryos were also found in the mother, although not all of them. Interestingly, we detected a high similarity in the composition of bacterial species among embryos from different mothers. These findings suggest that there may be a mechanism controlling the transmission of bacteria from the mother to the embryo. Our results highlight the possibility that the interaction between maternal bacteria and the embryo may affect the development of the lizards.

Microbial Dysbiosis and Male Infertility: Understanding the Impact and Exploring Therapeutic Interventions

The human microbiota in the genital tract is pivotal for maintaining fertility, but its disruption can lead to male infertility. This study examines the relationship between microbial dysbiosis and male infertility, underscoring the promise of precision medicine in this field. Through a comprehensive review, this research indicates microbial signatures associated with male infertility, such as altered bacterial diversity, the dominance of pathogenic species, and imbalances in the genital microbiome. Key mechanisms linking microbial dysbiosis to infertility include inflammation, oxidative stress, and sperm structural deterioration. Emerging strategies like targeted antimicrobial therapies, probiotics, prebiotics, and fecal microbiota transplantation have shown potential in adjusting the genital microbiota to enhance male fertility. Notably, the application of precision medicine, which customizes treatments based on individual microbial profiles and specific causes of infertility, emerges as a promising approach to enhance treatment outcomes. Ultimately, microbial dysbiosis is intricately linked to male infertility, and embracing personalized treatment strategies rooted in precision medicine principles could be the way forward in addressing infertility associated with microbial factors.

The Influence of Ketogenic Diet on Gut Microbiota: Potential Benefits, Risks and Indications

The ketogenic diet (KD) restricts carbohydrate consumption, leading to an increase in ketone bodies, such as acetoacetate, β-hydroxybutyrate, and acetone, which are utilized as energy substrates. This dietary approach impacts several biochemical processes, resulting in improved clinical management of various disorders, particularly in childhood. However, the exact mechanisms underlying the efficacy of KD remain unclear. Interestingly, KD may also impact the gut microbiota, which plays a pivotal role in metabolism, nutrition, and the development of the immune and nervous systems. KD has gained popularity for its potential benefits in weight loss, blood sugar control, and certain neurological conditions. This narrative review sums up KD-related studies published over 30 years. While short-term studies have provided valuable insights into the effects of KD on the gut microbiota, persistent uncertainties surround its long-term efficacy and potential for inducing dysbiosis. The significant influence of KD on epigenetic mechanisms, intracellular pathways, and gut microbial composition underscores its potential as a therapeutic choice. However, a judicious consideration of the potential risks associated with the strict adherence to a low-carbohydrate, high-fat, and high-protein regimen over prolonged periods is imperative. As KDs gain popularity among the adolescent and young adult demographic for weight management, it becomes imperative to undertake additional research to comprehensively assess their impact on nutritional status and gut microbiota, ensuring a holistic and sustainable approach to medical nutrition.

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.

Pre- and Postnatal Determinants Shaping the Microbiome of the Newborn in the Opinion of Pregnant Women from Silesia (Poland)

Pre- and postnatal factors influence the formation of the newborn's microbiome as early as birth and the intrauterine period has a substantial impact on the composition of the baby's gastrointestinal microbiota and its subsequent development. This study intends to measure pregnant women's knowledge of the importance of microbiota for the health of the newborn. The sample was selected based on defined inclusion and exclusion criteria. The assessment of women's knowledge was assessed by the Kolmogorov-Smirnov and Kruskal-Wallis statistical tests. This study population comprised 291 adult pregnant women with a mean age of 28.4 ± 4.7 years. A total of 34% (n = 99), 35% (n = 101), and 31.3% (n = 91) were at the 1-3 trimester, respectively. The results showed that 36.4% of the women were aware that the intrauterine period changes the makeup of the gastrointestinal microbiota, whereas 5.8% exhibited awareness of the composition of the child's normal gut microbiota. Most of the women surveyed-(72.1%)-know that colonization of the tract occurs as early as the birth period. Women with student status (those who will pursue higher education in the future) and those who had given birth to the most children exhibited higher levels of knowledge.

Regulative development as a model for origin of life and artificial life studies

Using the formal framework of the Free Energy Principle, we show how generic thermodynamic requirements on bidirectional information exchange between a system and its environment can generate complexity. This leads to the emergence of hierarchical computational architectures in systems that operate sufficiently far from thermal equilibrium. In this setting, the environment of any system increases its ability to predict system behavior by "engineering" the system towards increased morphological complexity and hence larger-scale, more macroscopic behaviors. When seen in this light, regulative development becomes an environmentally-driven process in which "parts" are assembled to produce a system with predictable behavior. We suggest on this basis that life is thermodynamically favorable and that, when designing artificial living systems, human engineers are acting like a generic "environment".

Identification of Novel Biomarkers in Late Preterm Neonates with Respiratory Distress Syndrome (RDS) Using Urinary Metabolomic Analysis

Urine metabolomics is gaining traction as a means of identifying metabolic signatures associated with health and disease states. Thirty-one (31) late preterm (LP) neonates admitted to the neonatal intensive care unit (NICU) and 23 age-matched healthy LPs admitted to the maternity ward of a tertiary hospital were included in the study. Proton nuclear magnetic resonance (¹H NMR) spectroscopy was employed for urine metabolomic analysis on the 1st and 3rd days of life of the neonates. The data were analyzed using univariate and multivariate statistical analysis. A unique metabolic pattern of enhanced metabolites was identified in the NICU-admitted LPs from the 1st day of life. Metabolic profiles were distinct in LPs presenting with respiratory distress syndrome (RDS). The discrepancies likely reflect differences in the gut microbiota, either due to variations in nutrient intake or as a result of medical interventions, such as the administration of antibiotics and other medications. Altered metabolites could potentially serve as biomarkers for identifying critically ill LP neonates or those at high risk for adverse outcomes later in life, including metabolic risks. The discovery of novel biomarkers may uncover potential targets for drug discovery and optimal periods for effective intervention, offering a personalized approach.

Is there a placental microbiota? A critical review and re-analysis of published placental microbiota datasets

The existence of a placental microbiota is debated. The human placenta has historically been considered sterile and microbial colonization was associated with adverse pregnancy outcomes. Yet, recent DNA sequencing investigations reported a microbiota in typical human term placentas. However, this detected microbiota could represent background DNA or delivery-associated contamination. Using fifteen publicly available 16S rRNA gene datasets, existing data were uniformly re-analyzed with DADA2 to maximize comparability. While Amplicon Sequence Variants (ASVs) identified as Lactobacillus, a typical vaginal bacterium, were highly abundant and prevalent across studies, this prevalence disappeared after applying likely  DNA contaminant removal to placentas from term cesarean deliveries. A six-study sub-analysis targeting the 16S rRNA gene V4 hypervariable region demonstrated that bacterial profiles of placental samples and technical controls share principal bacterial ASVs and that placental samples clustered primarily by study origin and mode of delivery. Contemporary DNA-based evidence does not support the existence of a placental microbiota.ImportanceEarly-gestational microbial influences on human development are unclear. By applying DNA sequencing technologies to placental tissue, bacterial DNA signals were observed, leading some to conclude that a live bacterial placental microbiome exists in typical term pregnancy. However, the low-biomass nature of the proposed microbiome and high sensitivity of current DNA sequencing technologies indicate that the signal may alternatively derive from environmental or delivery-associated bacterial DNA contamination. Here we address these alternatives with a re-analysis of 16S rRNA gene sequencing data from 15 publicly available placental datasets. After identical DADA2 pipeline processing of the raw data, subanalyses were performed to control for mode of delivery and environmental DNA contamination. Both environment and mode of delivery profoundly influenced the bacterial DNA signal from term-delivered placentas. Aside from these contamination-associated signals, consistency was lacking across studies. Thus, placentas delivered at term are unlikely to be the original source of observed bacterial DNA signals.

The Metabolome and the Gut Microbiota for the Prediction of Necrotizing Enterocolitis and Spontaneous Intestinal Perforation: A Systematic Review

Necrotizing enterocolitis (NEC) is the most devastating gastrointestinal emergency in preterm neonates. Research on early predictive biomarkers is fundamental. This is a systematic review of studies applying untargeted metabolomics and gut microbiota analysis to evaluate the differences between neonates affected by NEC (Bell’s stage II or III), and/or by spontaneous intestinal perforation (SIP) versus healthy controls. Five studies applying metabolomics (43 cases, 95 preterm controls) and 20 applying gut microbiota analysis (254 cases, 651 preterm controls, 22 term controls) were selected. Metabolomic studies utilized NMR spectroscopy or mass spectrometry. An early urinary alanine/histidine ratio >4 showed good sensitivity and predictive value for NEC in one study. Samples collected in proximity to NEC diagnosis demonstrated variable pathways potentially related to NEC. In studies applying untargeted gut microbiota analysis, the sequencing of the V3−V4 or V3 to V5 regions of the 16S rRNA was the most used technique. At phylum level, NEC specimens were characterized by increased relative abundance of Proteobacteria compared to controls. At genus level, pre-NEC samples were characterized by a lack or decreased abundance of Bifidobacterium. Finally, at the species level Bacteroides dorei, Clostridium perfringens and perfringens-like strains dominated early NEC specimens, whereas Clostridium butyricum, neonatale and Propionibacterium acnei those at disease diagnosis. Six studies found a lower Shannon diversity index in cases than controls. A clear separation of cases from controls emerged based on UniFrac metrics in five out of seven studies. Importantly, no studies compared NEC versus SIP. Untargeted metabolomics and gut microbiota analysis are interrelated strategies to investigate NEC pathophysiology and identify potential biomarkers. Expression of quantitative measurements, data sharing via biorepositories and validation studies are fundamental to guarantee consistent comparison of results.

Hypertension and renal disease programming: focus on the early postnatal period

The developmental origin of hypertension and renal disease is a concept highly supported by strong evidence coming from both human and animal studies. During development there are periods in which the organs are more vulnerable to stressors. Such periods of susceptibility are also called 'sensitive windows of exposure'. It was shown that as earlier an adverse event occurs; the greater are the consequences for health impairment. However, evidence show that the postnatal period is also quite important for hypertension and renal disease programming, especially in rodents because they complete nephrogenesis postnatally, and it is also important during preterm human birth. Considering that the developing kidney is vulnerable to early-life stressors, renal programming is a key element in the developmental programming of hypertension and renal disease. The purpose of this review is to highlight the great number of studies, most of them performed in animal models, showing the broad range of stressors involved in hypertension and renal disease programming, with a particular focus on the stressors that occur during the early postnatal period. These stressors mainly include undernutrition or specific nutritional deficits, chronic behavioral stress, exposure to environmental chemicals, and pharmacological treatments that affect some important factors involved in renal physiology. We also discuss the common molecular mechanisms that are activated by the mentioned stressors and that promote the appearance of these adult diseases, with a brief description on some reprogramming strategies, which is a relatively new and promising field to treat or to prevent these diseases.

Urine Metabolomic Profile of Breast- versus Formula-Fed Neonates Using a Synbiotic-Enriched Formula

The aim of this study was to compare the urine metabolic fingerprint of healthy neonates exclusively breastfed with that of neonates fed with a synbiotic-enriched formula (Rontamil^® Complete 1) at four time points (the 3rd and 15th days of life and the 2nd and 3rd months). The determination of urine metabolic fingerprint was performed using NMR metabolomics. Multivariate data analyses were performed with SIMCA-P 15.0 software and R language. Non-distinct profiles for both groups (breastfeeding and synbiotic formula) for the two first time points (3rd and 15th days of life) were detected, whereas after the 2nd month of life, a discrimination trend was observed between the two groups, which was further confirmed at the 3rd month of life. A clear discrimination of the synbiotic formula samples was evident when comparing the metabolites taken in the first days of life (3rd day) with those taken in the 2nd and 3rd months of life. In both cases, OPLS-DA models explained more than 75% of the metabolic variance. Non-distinct metabolomic profiles were obtained between breastfed and synbiotic-formula-fed neonates up to the 15th day of life. Discrimination trends were observed only after the 2nd month of the study, which could be attributed to breastfeeding variations and the consequent dynamic profile of urine metabolites compared to the stable ingredients of the synbiotic formula.

Biomolecular Mechanisms of Autoimmune Diseases and Their Relationship with the Resident Microbiota: Friend or Foe?

The use of innovative approaches to elucidate the pathophysiological mechanisms of autoimmune diseases, as well as to further study of the factors which can have either a positive or negative effect on the course of the disease, is essential. In this line, the development of new molecular techniques and the creation of the Human Genome Program have allowed access to many more solutions to the difficulties that exist in the identification and characterization of the microbiome, as well as changes due to various factors. Such innovative technologies can rekindle older hypotheses, such as molecular mimicry, allowing us to move from hypothesis to theory and from correlation to causality, particularly regarding autoimmune diseases and dysbiosis of the microbiota. For example, Prevotella copri appears to have a strong association with rheumatoid arthritis; it is expected that this will be confirmed by several scientists, which, in turn, will make it possible to identify other mechanisms that may contribute to the pathophysiology of the disease. This article seeks to identify new clues regarding similar correlations between autoimmune activity and the human microbiota, particularly in relation to qualitative and quantitative microbial variations therein.

Effect of invasive mechanical ventilation on the diversity of the pulmonary microbiota

Pulmonary microbial diversity may be influenced by biotic or abiotic conditions (e.g., disease, smoking, invasive mechanical ventilation (MV), etc.). Specially, invasive MV may trigger structural and physiological changes in both tissue and microbiota of lung, due to gastric and oral microaspiration, altered body posture, high O2 inhalation-induced O2 toxicity in hypoxemic patients, impaired airway clearance and ventilator-induced lung injury (VILI), which in turn reduce the diversity of the pulmonary microbiota and may ultimately lead to poor prognosis. Furthermore, changes in (local) O2 concentration can reduce the diversity of the pulmonary microbiota by affecting the local immune microenvironment of lung. In conclusion, systematic literature studies have found that invasive MV reduces pulmonary microbiota diversity, and future rational regulation of pulmonary microbiota diversity by existing or novel clinical tools (e.g., lung probiotics, drugs) may improve the prognosis of invasive MV treatment and lead to more effective treatment of lung diseases with precision.

In Vitro Gut Fermentation of Whey Protein Hydrolysate: An Evaluation of Its Potential Modulation on Infant Gut Microbiome

Whey protein and its hydrolysate are ubiquitously consumed as nutritional supplements. This study aimed to evaluate the potential effect of whey protein hydrolysate (WPH) on the infant gut microbiome, which is more variable than that of adults. Colonic fermentation was simulated through a static digestion model and fecal culture fermentation, using feces from normal infants aged from 1−3 years old. During in vitro gut fermentation, measurements of short-chain fatty acids (SCFA) concentrations and 16S rRNA amplicon sequencing were performed. Additionally, the growth curves of cultivated probiotics were analyzed to evaluate the prebiotic potential of WPH. Besides the decline of pH in fermentation, the addition of WPH induced a significant increase in the SCFA production and also the relative abundance of Proteobacteria, Bacteroides, and Streptococcus (p < 0.05). The lower ratio of Firmicutes/Bacteroidetes in WPH-supplemented samples indicated the positive modulation of WPH on the gut microbiota, which could benefit the energy balance and metabolism of infants. The stimulation effect of WPH on the probiotics (particularly Lactobacillus acidophilus NCFM) during cultivation implied the prebiotic potential as well. Our findings shed light on WPH as a valuable dietary supplement with not only enriched resources of essential amino acids but also the potential to restore the infant gut microbiome.

The Maternal–Fetal Gut Microbiota Axis: Physiological Changes, Dietary Influence, and Modulation Possibilities

The prenatal period and the first years of life have a significant impact on the health issues and life quality of an individual. The appropriate development of the immune system and the central nervous system are thought to be major critical determining events. In parallel to these, establishing an early intestinal microbiota community is another important factor for future well-being interfering with prenatal and postnatal developmental processes. This review aims at summarizing the main characteristics of maternal gut microbiota and its possible transmission to the offspring, thereby affecting fetal and/or neonatal development and health. Since maternal dietary factors are potential modulators of the maternal–fetal microbiota axis, we will outline current knowledge on the impact of certain diets, nutritional factors, and nutritional modulators during pregnancy on offspring’s microbiota and health.

Impact of Contaminants on Microbiota: Linking the Gut-Brain Axis with Neurotoxicity

Over the last years, research has focused on microbiota to establish a missing link between neuronal health and intestine imbalance. Many studies have considered microbiota as critical regulators of the gut–brain axis. The crosstalk between microbiota and the central nervous system is mainly explained through three different pathways: the neural, endocrine, and immune pathways, intricately interconnected with each other. In day-to-day life, human beings are exposed to a wide variety of contaminants that affect our intestinal microbiota and alter the bidirectional communication between the gut and brain, causing neuronal disorders. The interplay between xenobiotics, microbiota and neurotoxicity is still not fully explored, especially for susceptible populations such as pregnant women, neonates, and developing children. Precisely, early exposure to contaminants can trigger neurodevelopmental toxicity and long-term diseases. There is growing but limited research on the specific mechanisms of the microbiota–gut–brain axis (MGBA), making it challenging to understand the effect of environmental pollutants. In this review, we discuss the biological interplay between microbiota–gut–brain and analyse the role of endocrine-disrupting chemicals: Bisphenol A (BPA), Chlorpyrifos (CPF), Diethylhexyl phthalate (DEHP), and Per- and polyfluoroalkyl substances (PFAS) in MGBA perturbations and subsequent neurotoxicity. The complexity of the MGBA and the changing nature of the gut microbiota pose significant challenges for future research. However, emerging in-silico models able to analyse and interpret meta-omics data are a promising option for understanding the processes in this axis and can help prevent neurotoxicity.

Metabolomic profiles and microbiota of GDM offspring: The key for future perspective?

Gestational diabetes mellitus (GDM), or any degree of glucose intolerance recognized for the first time during pregnancy, is one of the diseases that most frequently aggravates the course of gestation. Missed or late diagnosis and inadequate treatment are associated with high maternal and fetal morbidity, with possible short- and long-term repercussions. Estimates on the prevalence of GDM are alarming and increasing by about 30% in the last 10-20 years. In addition, there is the negative influence of the SARS-CoV-2 emergency on the glycemic control of pregnant women, making the matter increasingly topical. To date, knowledge on the metabolic maturation of newborns is still incomplete. However, in light of the considerable progress of the theory of "developmental origins of health and disease," the relevant role of the intrauterine environment cannot be overlooked. In fact, due to the high plasticity of the early stages of development, some detrimental metabolic alterations during fetal growth, including maternal hyperglycemia, are associated with a higher incidence of chronic diseases in adult life. In this context, metabolomic analysis which allows to obtain a detailed phenotypic portrait through the dynamic detection of all metabolites in cells, tissues and different biological fluids could be very useful for the early diagnosis and prevention of complications. Indeed, if the diagnostic timing is optimized through the identification of specific metabolites, the detailed understanding of the altered metabolic pathway could also allow better management and more careful monitoring, also from a nutritional profile, of the more fragile children. In this context, a further contribution derives from the analysis of the intestinal microbiota, the main responsible for the fecal metabolome, given its alteration in pregnancies complicated by GDM and the possibility of transmission to offspring. The purpose of this review is to analyze the available data regarding the alterations in the metabolomic profile and microbiota of the offspring of mothers with GDM in order to highlight future prospects for reducing GDM-related complications in children of mothers affected by this disorder.

Reconstitution and Transmission of Gut Microbiomes and Their Genes between Generations

Microbiomes are transmitted between generations by a variety of different vertical and/or horizontal modes, including vegetative reproduction (vertical), via female germ cells (vertical), coprophagy and regurgitation (vertical and horizontal), physical contact starting at birth (vertical and horizontal), breast-feeding (vertical), and via the environment (horizontal). Analyses of vertical transmission can result in false negatives (failure to detect rare microbes) and false positives (strain variants). In humans, offspring receive most of their initial gut microbiota vertically from mothers during birth, via breast-feeding and close contact. Horizontal transmission is common in marine organisms and involves selectivity in determining which environmental microbes can colonize the organism's microbiome. The following arguments are put forth concerning accurate microbial transmission: First, the transmission may be of functions, not necessarily of species; second, horizontal transmission may be as accurate as vertical transmission; third, detection techniques may fail to detect rare microbes; lastly, microbiomes develop and reach maturity with their hosts. In spite of the great variation in means of transmission discussed in this paper, microbiomes and their functions are transferred from one generation of holobionts to the next with fidelity. This provides a strong basis for each holobiont to be considered a unique biological entity and a level of selection in evolution, largely maintaining the uniqueness of the entity and conserving the species from one generation to the next.

Human Milk, More Than Simple Nourishment

Human breast milk not only has nutritional properties but also holds a functional role. It contains various bioactive factors (lactoferrin, lysozyme, leukocytes, immunoglobulins, cytokines, hormones, human milk oligosaccharides, microbiome, microRNAs and stem cells) shown to contribute to several short- and long-term health outcomes. Some of these factors appear to be involved in the infant's neuro-cognitive development, anti-oncogenic processes, cellular communication and differentiation. Furthermore, breast milk is increasingly recognized to have dynamic characteristics and to play a fundamental role in the cross-talking mother-neonate. This narrative review aims to provide a summary and an update on these bioactive substances, exploring their functions mainly on immunomodulation, microbiome and virome development. Although the knowledge about breast milk potentiality has significantly improved, leading to discovering unexpected functions, the exact mechanisms with which breast milk exercises its bioactivity have not been completely clarified. This can represent a fertile ground for exploring and understanding the complexity behind these functional elements to develop new therapeutic strategies.

The reproductive tract microbiota in pregnancy

The reproductive tract microbiota plays a crucial role in maintenance of normal pregnancy and influences reproductive outcomes. Microbe–host interactions in pregnancy remain poorly understood and their role in shaping immune modulation is still being uncovered. In this review, we describe the composition of vaginal microbial communities in the reproductive tract and their association with reproductive outcomes. We also consider strategies for manipulating microbiota composition by using live biotherapeutics, selective eradication of pathogenic bacteria with antibiotics and vaginal microbiota transplantation. Finally, future developments in this field and the need for mechanistic studies to explore the functional significance of reproductive tract microbial communities are highlighted.

Breast Milk and COVID-19: From Conventional Data to "Omics" Technologies to Investigate Changes Occurring in SARS-CoV-2 Positive Mothers

In this context of COVID-19 pandemic, great interest has been aroused by the potential maternal transmission of SARS-CoV-2 by transplacental route, during delivery, and, subsequently, through breastfeeding. Some open questions still remain, especially regarding the possibility of finding viable SARS-CoV-2 in breast milk (BM), although this is not considered a worrying route of transmission. However, in BM, it was pointed out the presence of antibodies against SARS-CoV-2 and other bioactive components that could protect the infant from infection. The aim of our narrative review is to report and discuss the available literature on the detection of anti-SARS-CoV-2 antibodies in BM of COVID-19 positive mothers, and we discussed the unique existing study investigating BM of SARS-CoV-2 positive mothers through metabolomics, and the evidence regarding microbiomics BM variation in COVID-19. Moreover, we tried to correlate metabolomics and microbiomics findings in BM of positive mothers with potential effects on breastfed infants metabolism and health. To our knowledge, this is the first review summarizing the current knowledge on SARS-CoV-2 effects on BM, resuming both "conventional data" (antibodies) and "omics technologies" (metabolomics and microbiomics).

Microbial Contamination in Hospital Environment Has the Potential to Colonize Preterm Newborns' Nasal Cavities

Infants born before 28 weeks are at risk of contracting healthcare-associated infections (HAIs), which could be caused by pathogens residing on contaminated hospital surfaces. In this longitudinal study, we characterized by NGS the bacterial composition of nasal swabs of preterm newborns, at the time of birth and after admission to the Neonatal Intensive Care Unit (NICU), comparing it with that of the environmental wards at the time of delivery and during the hospitalization. We characterized the resistome on the samples too. The results showed that environmental microorganisms responsible for HAIs, in particular Staphylococcus spp., Streptococcus spp., Escherichia-Shigella spp., and K. pneumoniae, were detected in higher percentages in the noses of the babies after 13 days of hospitalization, in terms of the number of colonized patients, microorganism amount, and relative abundance. The analysis of nasal bacteria resistome evidenced the absence of resistance genes at the time of birth, some of which appeared and increased after the admission in the NICU. These data suggest that hospital surface microbiota might be transported to respiratory mucosae or other profound tissues. Our study highlights the importance of a screening that allows characterizing the microbial profile of the environment to assess the risk of colonization of the newborn.

Brown Adipose Tissue: New Challenges for Prevention of Childhood Obesity. A Narrative Review

Pediatric obesity remains a challenge in modern society. Recently, research has focused on the role of the brown adipose tissue (BAT) as a potential target of intervention. In this review, we revised preclinical and clinical works on factors that may promote BAT or browning of white adipose tissue (WAT) from fetal age to adolescence. Maternal lifestyle, type of breastfeeding and healthy microbiota can affect the thermogenic activity of BAT. Environmental factors such as exposure to cold or physical activity also play a role in promoting and activating BAT. Most of the evidence is preclinical, although in clinic there is some evidence on the role of omega-3 PUFAs (EPA and DHA) supplementation on BAT activation. Clinical studies are needed to dissect the early factors and their modulation to allow proper BAT development and functions and to prevent onset of childhood obesity.