Parental dietary fat intake alters offspring microbiome and immunity

Virus Infections and Host Metabolism-Can We Manage the Interactions?

When viruses infect cells, they almost invariably cause metabolic changes in the infected cell as well as in several host cell types that react to the infection. Such metabolic changes provide potential targets for therapeutic approaches that could reduce the impact of infection. Several examples are discussed in this review, which include effects on energy metabolism, glutaminolysis and fatty acid metabolism. The response of the immune system also involves metabolic changes and manipulating these may change the outcome of infection. This could include changing the status of herpesviruses infections from productive to latency. The consequences of viral infections which include coronavirus disease 2019 (COVID-19), may also differ in patients with metabolic problems, such as diabetes mellitus (DM), obesity, and endocrine diseases. Nutrition status may also affect the pattern of events following viral infection and examples that impact on the pattern of human and experimental animal viral diseases and the mechanisms involved are discussed. Finally, we discuss the so far few published reports that have manipulated metabolic events in-vivo to change the outcome of virus infection. The topic is expected to expand in relevance as an approach used alone or in combination with other therapies to shape the nature of virus induced diseases.

Evidence for maternal diet-mediated effects on the offspring microbiome and immunity: implications for public health initiatives

Diets rich in saturated fats have become a staple globally. Fifty percent of women of childbearing age in the United States are obese or overweight, with diet being a significant contributor. There is increasing evidence of the impact of maternal high-fat diet on the offspring microbiome. Alterations of the neonatal microbiome have been shown to be associated with multiple morbidities, including the development of necrotizing enterocolitis, atopy, asthma, metabolic dysfunction, and hypertension among others. This review provides an overview of the recent studies and mechanisms being examined on how maternal diet can alter the immune response and microbiome in offspring and the implications for directed public health initiatives for women of childbearing age. IMPACT: Maternal diet is important in shaping the offspring microbiome and neonatal immune system. Reviews the current literature in the field and suggests potential mechanisms and areas of research to be targeted. Highlights the current scope of our knowledge of ideal nutrition during pregnancy and consideration for enhanced public health initiatives to promote well-being of the future generation.

Microbiome and Gestational Diabetes: Interactions with Pregnancy Outcome and Long-Term Infant Health

Microbiota composition is progressively being connected to different physiologic effects, such as glucose metabolism, and also to different pathologies, such as gestational diabetes mellitus (GDM). GDM is a public health concern that affects an important percentage of pregnancies and is correlated with many adverse maternal and neonatal outcomes. An increasing number of studies are showing some connections between specific microbial composition of the gut microbiota and development of GDM and adverse outcomes in mothers and neonates. The aim of this review is to analyze the available data on microbial changes that characterize healthy pregnancies and pregnancies complicated by GDM and to understand the correlation of these changes with adverse maternal outcomes; this review will also discuss the consequences of these maternal gut microbiome alterations on neonatal microbiota composition and neonatal long-term outcomes.

Maternal Sweeteners Intake Modulates Gut Microbiota and Exacerbates Learning and Memory Processes in Adult Male Offspring

Background: There is increasing evidence that gut microbiota in offspring is derived in part from maternal environment such as diet. Thus, sweeteners intake including caloric or non-caloric during perinatal period can induce gut dysbiosis and program the offspring to develop cognitive problems later in life. Objective: To determine the effect of maternal high-sweeteners intake during gestation and lactation on gut microbiota shifts in adult male offspring rats and the impact on cognitive dysfunction. Methods: Thirty-four male pups from dams fed standard diet (Control-C, n = 10), high-sucrose diet (HS-C, n = 11), high-honey diet (Ho-C, n = 8), and high-stevia diet (HSt-C, n = 5) were fed standard diet after weaning, and body weight and food intake were recorded once a week for 26 weeks. Learning and memory tests were performed at week 23 of life using the Barnes maze. Fecal samples from the breastfeeding and adulthood periods were collected and analyzed by sequencing the 16S rRNA V3-V4 region of gut microbiota. Results: Maternal high-sucrose and stevia diets programmed the male offspring, and changes in microbial diversity by Shannon index were observed after weaning (p < 0.01). Furthermore, maternal high-stevia diet programming lasted into adulthood. The increase of Firmicutes abundance and the decrease in phylum Bacteroidetes were significant in HS-C and HSt-C groups. This led to an increase in the Firmicutes/Bacteroidetes index, although only in HS-C group was statistically significant (p < 0.05). Of note, the downstream gram-negative Bacteroidales and the upregulation of the gram-positive Clostridiales abundance contribute to cognitive dysfunction. Conclusion: These results suggest that dams fed a high-sucrose and stevia diets during gestation and lactation favor a deficient memory performance in adult male offspring rats through shifts gut microbiota diversity and relative abundance at several taxa.

Maternal sitagliptin treatment attenuates offspring glucose metabolism and intestinal proinflammatory cytokines IL-6 and TNF-α expression in male rats

Increasing evidence shows that maternal overnutrition may increase the risk of diabetes in offspring. We hypothesized that maternal sitagliptin intervention may improve glucose intolerance through gut targeting. Female Sprague-Dawley (SD) rats were fed a normal diet (ND) or a high-fat diet (HFD) for 4 weeks before mating. ND pregnant rats were divided into two subgroups: ND group (ND alone) and the ND-sitagliptin group (ND combined with 10 mg/kg/day sitagliptin treatment). HFD pregnant rats were randomized to one of two groups: HFD group (HFD alone) and the HFD-sitagliptin group (HFD combined with 10 mg/kg/day sitagliptin treatment) during pregnancy and lactation. Glucose metabolism was assessed in offspring at weaning. Intestinal gene expression levels were investigated. Maternal sitagliptin intervention moderated glucose intolerance and insulin resistance in male pups. Moreover, maternal sitagliptin treatment inhibited offspring disordered intestinal expression of proinflammatory markers, including interleukin-6 (Il6), ll1b, and tumor necrosis factor (Tnf), at weaning and reduced intestinal IL-6, TNF-α expression by immunohistochemical staining and serum IL-6, TNF-α levels. However, maternal sitagliptin intervention did not affect offspring serum anti-inflammatory cytokine IL-10 level. Our results are the first to show that maternal sitagliptin intervention moderated glucose metabolism in male offspring. It may be involved with moderating intestinal IL-6 and TNF-α expression in male rat offspring.

Maternal Linoleic Acid Overconsumption Alters Offspring Gut and Adipose Tissue Homeostasis in Young but Not Older Adult Rats

Maternal n-6 polyunsaturated fatty acids (PUFA) consumption during gestation and lactation can predispose offspring to the development of metabolic diseases such as obesity later in life. However, the mechanisms underlying the potential programming effect of n-6 PUFA upon offspring physiology are not yet all established. Herein, we investigated the effects of maternal and weaning linoleic acid (LA)-rich diet interactions on gut intestinal and adipose tissue physiology in young (3-month-old) and older (6-month-old) adult offspring. Pregnant rats were fed a control diet (2% LA) or an LA-rich diet (12% LA) during gestation and lactation. At weaning, offspring were either maintained on the maternal diet or fed the other diet for 3 or 6 months. At 3 months of age, the maternal LA-diet favored low-grade inflammation and greater adiposity, while at 6 months of age, offspring intestinal barrier function, adipose tissue physiology and hepatic conjugated linoleic acids were strongly influenced by the weaning diet. The maternal LA-diet impacted offspring cecal microbiota diversity and composition at 3 months of age, but had only few remnant effects upon cecal microbiota composition at 6 months of age. Our study suggests that perinatal exposure to high LA levels induces a differential metabolic response to weaning diet exposure in adult life. This programming effect of a maternal LA-diet may be related to the alteration of offspring gut microbiota.

Supplementation with a prebiotic (polydextrose) in obese mouse pregnancy improves maternal glucose homeostasis and protects against offspring obesity

OBJECTIVES

We hypothesised that maternal diet-induced-obesity has adverse consequences for offspring energy expenditure and susceptibility to obesity in adulthood, and that the prebiotic polydextrose (PDX) would prevent the consequences of programming by maternal obesity.

METHODS

Female mice were fed a control (Con) or obesogenic diet (Ob) for 6 weeks prior to mating and throughout pregnancy and lactation. Half the obese dams were supplemented with 5% PDX (ObPDX) in drinking water throughout pregnancy and lactation. Offspring were weaned onto standard chow. At 3 and 6 months, offspring energy intake (EI) and energy expenditure (EE by indirect calorimetry) were measured, and a glucose-tolerance test performed. Offspring of control (OffCon), obese (OffOb) and PDX supplemented (OffObP) dams were subsequently challenged for 3 weeks with Ob, and energy balanced reassessed. Potential modifiers of offspring energy balance including gut microbiota and biomarkers of mitochondrial activity were also evaluated.

RESULTS

Six-month-old male OffOb demonstrated increased bodyweight (BW, P < 0.001) and white adipose tissue mass (P < 0.05), decreased brown adipose tissue mass (BAT, P < 0.01), lower night-time EE (P < 0.001) versus OffCon, which were prevented in OffObP. Both male and female OffOb showed abnormal glucose-tolerance test (peak [Glucose] P < 0.001; AUC, P < 0.05) which was prevented by PDX. The Ob challenge resulted in greater BW gain in both male and female OffOb versus OffCon (P < 0.05), also associated with increased EI (P < 0.05) and reduced EE in females (P < 0.01). OffObP were protected from accelerated BW gain on the OB diet compared with controls, associated with increased night-time EE in both male (P < 0.05) and female OffObP (P < 0.001). PDX also prevented an increase in skeletal muscle mtDNA copy number in OffOb versus OffCon (P < 0.01) and increased the percentage of Bacteroides cells in faecal samples from male OffObP relative to controls.

CONCLUSIONS

Maternal obesity adversely influences adult offspring energy balance and propensity for obesity, which is ameliorated by maternal PDX treatment with associated changes in gut microbiota composition and skeletal muscle mitochondrial function.

Developmental programming of peripheral diseases in offspring exposed to maternal obesity during pregnancy

Obesity is an increasing global health epidemic that affects all ages, including women of reproductive age. During pregnancy, maternal obesity is associated with adverse pregnancy outcomes that lead to complications for the mother. In addition, maternal obesity can increase the risk of poor perinatal outcomes for the infant due to altered development. Recent research has investigated the effects of maternal obesity on peripheral organ development and health in later life in offspring. In this review, we have summarized studies that investigated the programming effects of maternal obesity before and during pregnancy on metabolic, cardiovascular, immune, and microbiome perturbations in offspring. Epidemiological studies investigating the effects of maternal obesity on offspring development can be complex due to other copathologies and genetic diversity. Animal studies have provided some insights into the specific mechanisms and pathways involved in programming peripheral disease risk. The effects of maternal obesity during pregnancy on offspring development are often sex specific, with sex-specific changes in placental transport and function suggestive that this organ is likely to play a central role. We believe that this review will assist in facilitating future investigations regarding the underlying mechanisms that link maternal obesity and offspring disease risk in peripheral organs.

Maternal obesity increases offspring's mammary cancer recurrence and impairs tumor immune response

Over 50% of women at a childbearing age in the United States are overweight or obese, and this can adversely affect their offspring. We studied if maternal obesity-inducing high fat diet (HFD) not only increases offspring's mammary cancer risk but also impairs response to antiestrogen tamoxifen. Female rat offspring of HFD and control diet-fed dams, in which estrogen receptor-positive (ER+) mammary tumors were induced with the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA), exhibited similar initial responses to antiestrogen tamoxifen. However, after tamoxifen therapy was completed, almost all (91%) tumors recurred in HFD offspring, compared with only 29% in control offspring. The increase in local mammary tumor recurrence in HFD offspring was linked to an increase in the markers of immunosuppression (Il17f, Tgfβ1, VEGFR2) in the tumor microenvironment (TME). Protein and mRNA levels of the major histocompatibility complex II (MHC-II), but not MHC-I, were reduced in the recurring DMBA tumors of HFD offspring. Further, infiltration of CD8+ effector T cells and granzyme B+ (GZMB+) cells were lower in their recurring tumors. To determine if maternal HFD can pre-program similar changes in the TME of allografted E0771 mammary tumors in offspring of syngeneic mice, flow cytometry analysis was performed. E0771 mammary tumor growth was significantly accelerated in the HFD offspring, and a reduction in the numbers of GZMB and non-significant reduction of interferon γ (IFNγ) secreting CD8+ T cells in the TME was seen. Thus, consumption of a HFD during pregnancy increases susceptibility of the female rat and mouse offspring to tumor immune suppression and mammary tumor growth and recurrence.

Developmental Programming of NAFLD by Parental Obesity

The surge of obesity across generations has become an increasingly relevant issue, with consequences for associated comorbidities in offspring. Data from longitudinal birth cohort studies support an association between maternal obesity and offspring nonalcoholic fatty liver disease (NAFLD), suggesting that perinatal obesity or obesogenic diet exposure reprograms offspring liver and increases NAFLD susceptibility. In preclinical models, offspring exposed to maternal obesogenic diet have increased hepatic steatosis after diet-induced obesity; however, the implications for later NAFLD development and progression are still unclear. Although some models show increased NAFLD incidence and progression in offspring, development of nonalcoholic steatohepatitis with fibrosis may be model dependent. Multigenerational programming of NAFLD phenotypes occurs after maternal obesogenic diet exposure; however, the mechanisms for such programming remain poorly understood. Likewise, emerging data on the role of paternal obesity in offspring NAFLD development reveal incomplete mechanisms. This review will explore the impact of parental obesity and obesogenic diet exposure on offspring NAFLD and areas for further investigation, including the impact of parental diet on disease progression, and consider potential interventions in preclinical models.

Paternal weight of ducks may have an influence on offspring' small intestinal function and cecal microorganisms

Background

In animals, many factors affect the small intestinal function and cecal microorganisms, including body weight and genetic background. However, whether paternal weight impacts the small intestinal function and cecal microorganisms remains unknown to date. The current study used Nonghua sheldrake to estimate the effect of paternal weight on the intestine of the offspring by evaluating differences in small intestinal morphology, digestive enzyme activity, and cecal microorganisms between the offspring of male parents with high body weight (group H) and that of male parents with low body weight (group L).

Results

The results of the analysis of small intestinal morphology showed that the villus height of the jejunum of group H ducks was higher than that of group L ducks, and the difference was significant for ducks at 10 weeks of age. Moreover, the villus height/crypt depth of the duodenum in group H significantly exceeded that of group L at a duck age of 2 weeks. The amylase activity in the jejunum content of group H exceeded that of group L at 5 and 10 weeks of age. Furthermore, the proportion of the Firmicutes to Bacteroidetes was significantly higher in group H (duck age of 2 weeks). Among the genera with a relative abundance exceeding 1%, the relative abundances of genera Desulfovibrio, Megamonas, Alistipes, Faecalibacterium, and Streptococcus observed in group H were significantly different between group H and group L.

Conclusions

For the first time, this study identifies the effect of paternal weight on offspring small intestinal function and cecal microorganisms. Consequently, this lays a foundation for further research on the relationship between male parents and offspring intestinal function.

A dietary intervention to improve the microbiome composition of pregnant women with Crohn's disease and their offspring: The MELODY (Modulating Early Life Microbiome through Dietary Intervention in Pregnancy) trial design

Crohn's disease (CD), a type of inflammatory bowel disease (IBD), is a chronic condition of the gastrointestinal tract that is caused by the loss of mucosal tolerance towards the commensal bacteria resulting in inflammatory responses. It has long been postulated that the gut microbiota, a complex and dynamic population of microorganisms, plays a key role in the pathogenesis of IBD. Maternal diagnosis of IBD has been identified as the greatest risk factor for IBD in offspring increasing the odds of developing the disease >4.5-fold. Moreover, babies born to mothers with IBD have demonstrated reduced gut bacterial diversity. There is accumulating evidence that the early life microbiota colonization is informed by maternal diet within the 3rd trimester of pregnancy. While babies born to mothers with IBD would pose an ideal cohort for intervention, no primary prevention measures are currently available. Therefore, we designed the MELODY (Modulating Early Life Microbiome through Dietary Intervention in Pregnancy) trial to test whether the IBD-AID™ dietary intervention during the last trimester of pregnancy can beneficially shift the microbiome of CD patients and their babies, thereby promoting a strong, effective immune system during a critical time of the immune system development. We will also test if favorable changes in the microbiome can lead to a reduced risk of postpartum CD relapse and lower mucosal inflammation in the offspring. This study will help create new opportunities to foster a healthy microbiome in the offspring at high risk of other immune-mediated diseases, potentially reducing their risk later in life.

Early-Life Gut Microbiome-The Importance of Maternal and Infant Factors in Its Establishment

The early-life microbiome is gaining appreciation as a major influencer in human development and long-term health. Multiple factors are known to influence the initial colonization, development, and function of the neonatal gut microbiome. In addition, alterations in early-life gut microbial composition is associated with several chronic health conditions such as obesity, asthma, and allergies. In this review, we focus on both maternal and infant factors known to influence early-life gut colonization. Also reviewed is the important role of infant feeding, including evidence-based strategies for maternal and infant supplementation with the goal to protect and/or restore the infant gut microbiome.

Prenatal and postnatal determinants in shaping offspring's microbiome in the first 1000 days: study protocol and preliminary results at one month of life

BACKGROUND

Fetal programming during in utero life defines the set point of physiological and metabolic responses that lead into adulthood; events happening in "the first 1,000 days" (from conception to 2-years of age), play a role in the development of non-communicable diseases (NCDs). The infant gut microbiome is a highly dynamic organ, which is sensitive to maternal and environmental factors and is one of the elements driving intergenerational NCDs' transmission. The A.MA.MI (Alimentazione MAmma e bambino nei primi MIlle giorni) project aims at investigating the correlation between several factors, from conception to the first year of life, and infant gut microbiome composition. We described the study design of the A.MA.MI study and presented some preliminary results.

METHODS

A.MA.MI is a longitudinal, prospective, observational study conducted on a group of mother-infant pairs (n = 60) attending the Neonatal Unit, Fondazione IRCCS Policlinico San Matteo, Pavia (Italy). The study was planned to provide data collected at T0, T1, T2 and T3, respectively before discharge, 1,6 and 12 months after birth. Maternal and infant anthropometric measurements were assessed at each time. Other variables evaluated were: pre-pregnancy/gestational weight status (T0), maternal dietary habits/physical activity (T1-T3); infant medical history, type of feeding, antibiotics/probiotics/supplements use, environment exposures (e.g cigarette smoking, pets, environmental temperature) (T1-T3). Infant stool samples were planned to be collected at each time and analyzed using metagenomics 16S ribosomal RNA gene sequence-based methods.

RESULTS

Birth mode (cesarean section vs. vaginal delivery) and maternal pre pregnancy BMI (BMI < 25 Kg/m² vs. BMI ≥ 25 Kg/m²), significant differences were found at genera and species levels (T0). Concerning type of feeding (breastfed vs. formula-fed), gut microbiota composition differed significantly at genus and species level (T1).

CONCLUSION

These preliminary and explorative results confirmed that pre-pregnancy, mode of delivery and infant factors likely impact infant microbiota composition at different levels.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04122612.

Intergenerational Transmission of Diet-Induced Obesity, Metabolic Imbalance, and Osteoarthritis in Mice

OBJECTIVE

Obesity and osteoarthritis (OA) are 2 major public health issues affecting millions of people worldwide. Whereas parental obesity affects the predisposition to diseases such as cancer or diabetes in children, transgenerational influences on musculoskeletal conditions such as OA are poorly understood. This study was undertaken to assess the intergenerational effects of a parental/grandparental high-fat diet on the metabolic and skeletal phenotype, systemic inflammation, and predisposition to OA in 2 generations of offspring in mice.

METHODS

Metabolic phenotype and predisposition to OA were investigated in the first and second (F1 and F2) generations of offspring (n = 10-16 mice per sex per diet) bred from mice fed a high-fat diet (HFD) or a low-fat control diet. OA was induced by destabilizing the medial meniscus. OA, synovitis, and adipose tissue inflammation were determined histologically, while bone changes were measured using micro-computed tomography. Serum and synovial cytokines were measured by multiplex assay.

RESULTS

Parental high-fat feeding showed an intergenerational effect, with inheritance of increased weight gain (up to 19% in the F1 generation and 9% in F2), metabolic imbalance, and injury-induced OA in at least 2 generations of mice, despite the fact that the offspring were fed the low-fat diet. Strikingly, both F1 and F2 female mice showed an increased predisposition to injury-induced OA (48% higher predisposition in F1 and 19% in F2 female mice fed the HFD) and developed bone microarchitectural changes that were attributable to parental and grandparental high-fat feeding.

CONCLUSION

The results of this study reveal a detrimental effect of parental HFD and obesity on the musculoskeletal integrity of 2 generations of offspring, indicating the importance of further investigation of these effects. An improved understanding of the mechanisms involved in the transmissibility of diet-induced changes through multiple generations may help in the development of future therapies that would target the effects of obesity on OA and related conditions.

The role of maternal diet on offspring gut microbiota development: A review

In offspring, an adequate maternal diet is important for neurodevelopment. One mechanism by which maternal diet impacts neurodevelopment is through its dynamic role in the development of the gut microbiota. Communication between the gut, and its associated microbiota, and the brain is facilitated by the vagus nerve, in addition to other routes. Currently, the mechanisms through which maternal diet impacts offspring microbiota development are not well-defined. Therefore, this review aims to investigate the relationship between maternal diet during pregnancy and offspring microbiota development and its impact on neurodevelopment. Both human and animal model studies were reviewed to understand the impact of maternal diet on offspring microbiota development and potential consequences on neurodevelopment. In the period after birth, as reported in both human and model system studies, maternal diet impacts offspring bacterial colonization (e.g., decreased presence of Lactobacillus reuteri as a result of a high-fat maternal diet). It remains unknown whether these changes persist into adulthood and whether they impact vulnerability to disease. Therefore, further long-term studies are required in both human and model systems to study these changes. Our survey of the literature indicates that maternal diet influences early postnatal microbiota development, which in turn, may serve as a mechanism through which maternal diet impacts neurodevelopment.

Naturally-diverse airborne environmental microbial exposures modulate the gut microbiome and may provide anxiolytic benefits in mice

Growing epidemiological evidence links natural green space exposure with a range of health benefits, including for mental health. Conversely, greater urbanisation associates with increased risk of mental health disorders. Microbiomes are proposed as an important but understudied link that may help explain many green space-human health associations. However, there remains a lack of controlled experimental evidence testing possible beneficial effects from passive exposure to natural biodiversity via airborne microbiota. Previous mouse model studies have used unrealistic environmental microbial exposures-including excessive soil and organic matter contact, feed supplements and injections-to demonstrate host microbiota, immune biomarker, and behavioural changes. Here, in a randomised controlled experiment, we demonstrate that realistic exposures to trace-level dust from a high biodiversity soil can change mouse gut microbiota, in comparison to dust from low biodiversity soil or no soil (control) (n = 54 total mice, comprising 3 treatments × 18 mice, with 9 females + 9 males per group). Furthermore, we found a nominal soil-derived anaerobic spore-forming butyrate-producer, Kineothrix alysoides, was supplemented to a greater extent in the gut microbiomes of high biodiversity treatment mice. Also, increasing relative abundance of this rare organism correlated with reduced anxiety-like behaviour in the most anxious mice. Our results point to an intriguing new hypothesis: that biodiverse soils may represent an important supplementary source of butyrate-producing bacteria capable of resupplying the mammalian gut microbiome, with potential for gut health and mental health benefits. Our findings have potential to inform cost-effective population health interventions through microbiome-conscious green space design and, ultimately, the mainstreaming of biodiversity into health care.

Review: Impact of food, gut-brain signals and metabolic status on brain activity in the pig model: 10 years of nutrition research using in vivo brain imaging

The purpose of this review is to offer a panorama on 10 years of nutrition research using in vivo brain imaging in the pig model. First, we will review some work describing the brain responses to food signals, including basic tastants such as sweet and bitter at both oral and visceral levels, as well as conditioned preferred and aversive flavours. Second, we will have a look at the impact of weight gain and obesity on brain metabolism and functional responses, drawing the parallel with obese human patients. Third, we will evoke the concept of the developmental origins of health and diseases, and how the pig model can shed light on the importance of maternal nutrition during gestation and lactation for the development of the gut-brain axis and adaptation abilities of the progeny to nutritional environments. Finally, three examples of preventive or therapeutic strategies will be introduced: the use of sensory food ingredients or pre-, pro-, and postbiotics to improve metabolic and cognitive functions; the implementation of chronic vagus nerve stimulation to prevent weight gain and glucose metabolism alterations; and the development of bariatric surgery in the pig model for the understanding of its complex mechanisms at the gut-brain level. A critical conclusion will brush the limitations of neurocognitive studies in the pig model and put in perspective the rationale and ethical concerns underlying the use of pig experimentation in nutrition and neurosciences.

Potential Role of Gut Microbiota in Induction and Regulation of Innate Immune Memory

The gut microbiota significantly regulates the development and function of the innate and adaptive immune system. The attribute of immunological memory has long been linked only with adaptive immunity. Recent evidence indicates that memory is also present in the innate immune cells such as monocytes/macrophages and natural killer cells. These cells exhibit pattern recognition receptors (PRRs) that recognize microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs) expressed by the microbes. Interaction between PRRs and MAMPs is quite crucial since it triggers the sequence of signaling events and epigenetic rewiring that not only play a cardinal role in modulating the activation and function of the innate cells but also impart a sense of memory response. We discuss here how gut microbiota can influence the generation of innate memory and functional reprogramming of bone marrow progenitors that helps in protection against infections. This article will broaden our current perspective of association between the gut microbiome and innate memory. In the future, this knowledge may pave avenues for development and designing of novel immunotherapies and vaccination strategies.

Microbiome Big-Data Mining and Applications Using Single-Cell Technologies and Metagenomics Approaches Toward Precision Medicine

With the development of high-throughput sequencing technologies as well as various bioinformatics analytic tools, microbiome is not a “microbial dark matter” anymore. In this review, we first summarized the current analytical strategies used for big-data mining such as single-cell sequencing and metagenomics. We then provided insights into the integration of these strategies, showing significant advantages in fully describing microbiome from multiple aspects. Moreover, we discussed the correlation between gut microbiome with host organs and diseases, confirming the importance of big-data mining in clinical practices. We finally proposed new ideas about the trend of big-data mining in microbiome using multi-omics approaches and single-cell sequencing. The integration of multi-omics approaches and single-cell sequencing can provide full understanding of microbiome at both macroscopic level and microscopic level, thus contributing to precision medicine.

Influence of maternal microbiota during pregnancy on infant immunity

Microbiota from various maternal sites, including the gut, vagina and breast milk, are known to influence colonization in infants. However, emerging evidence suggests that these sites may exert their influence prior to delivery, in turn influencing fetal immune development. The dogma of a sterile womb continues to be challenged. Regardless, there is convincing evidence that the composition of the maternal gut prior to delivery influences neonatal immunity. Therefore, while the presence and function of placental microbiome is not clear, there is consensus that the gut microbiota during pregnancy is a critical determinant of offspring health. Data supporting the notion of bacterial translocation from the maternal gut to extra-intestinal sites during pregnancy are emerging, and potentially explain the presence of bacteria in breast milk. Much evidence suggests that the maternal gut microbiota during pregnancy potentially determines the development of atopy and autoimmune phenotypes in offspring. Here, we highlight the role of the maternal microbiota prior to delivery on infant immunity and predisposition to diseases. Moreover, we discuss potential mechanisms that underlie this phenomenon.

Maternal Obesity and Offspring Long-Term Infectious Morbidity

Obesity is a leading cause of morbidity world-wide. Maternal obesity is associated with adverse perinatal outcomes. Furthermore, Obesity has been associated with increased susceptibility to infections. The purpose of this study was to evaluate long-term pediatric infectious morbidity of children born to obese mothers. This population-based cohort analysis compared deliveries of obese (maternal pre-pregnancy BMI ≥ 30 kg/m²) and non-obese patients at a single tertiary medical center. Hospitalizations of the offspring up to the age of 18 years involving infectious morbidities were evaluated according to a predefined set of ICD-9 codes. A Kaplan–Meier survival curve was used to compare cumulative hospitalization incidence between the groups and Cox proportional hazards model was used to control for possible confounders. 249,840 deliveries were included. Of them, 3399 were children of obese mothers. Hospitalizations involving infectious morbidity were significantly more common in children born to obese mothers compared with non-obese patients (12.5% vs. 11.0%, p < 0.01). The Kaplan–Meier survival curve demonstrated a significantly higher cumulative incidence of infectious-related hospitalizations in the obese group (log rank p = 0.03). Using the Cox regression model, maternal obesity was found to be an independent risk factor for long-term infectious morbidity of the offspring (adjusted HR = 1.125, 95% CI 1.021–1.238, p = 0.017).

Impact of pregravid obesity on maternal and fetal immunity: Fertile grounds for reprogramming

Maternal pregravid obesity results in several adverse health outcomes during pregnancy, including increased risk of gestational diabetes, preeclampsia, placental abruption, and complications at delivery. Additionally, pregravid obesity and in utero exposure to high fat diet have been shown to have detrimental effects on fetal programming, predisposing the offspring to adverse cardiometabolic, endocrine, and neurodevelopmental outcomes. More recently, a deeper appreciation for the modulation of offspring immunity and infectious disease-related outcomes by maternal pregravid obesity has emerged. This review will describe currently available animal models for studying the impact of maternal pregravid obesity on fetal immunity and review the data from clinical and animal model studies. We also examine the burden of pregravid obesity on the maternal-fetal interface and the link between placental and systemic inflammation. Finally, we discuss future studies needed to identify key mechanistic underpinnings that link maternal inflammatory changes and fetal cellular reprogramming events.

Microbiota signatures relating to reduced memory and exploratory behaviour in the offspring of overweight mothers in a murine model

An elevated number of women of reproductive age are overweight, predisposing their offspring to metabolic and neuropsychiatric disorders. Gut microbiota is influenced by maternal factors, and has been implicated in the pathogenesis of neurodegenerative diseases. Our aim was to explore the effects of maternal high-fat feeding on the relationship linking gut microbiota and cognitive development in the offspring. Murine offspring born to dams undergoing normal diet (NDm) and high-fat diet (HFDm) were studied at 1 or 6 months of age to assess cognitive function by Y-maze test, cerebral glucose metabolism and insulin sensitivity by Positron Emission Tomography, brain density by Computed Tomography, microbiota profile (colon, caecum) and inferred metabolic pathways (KEGG analysis) by 16S ribosomal RNA sequencing. From 3 weeks post-weaning, mice born to HFDm developed hyperphagia and overweight, showing reduction in memory and exploratory behaviour, and brain insulin resistance in adulthood. We identified a panel of bacteria characterizing offspring born to HFD dams from early life, and correlating with dysfunction in memory and exploratory behaviour in adults (including Proteobacteria phylum, Parabacteroides and unclassified Rikenellaceae genera). Microbiota-derived metabolic pathways involved in fatty acid, essential aminoacid and vitamin processing, sulphur metabolism, glutaminergic activation and Alzheimer’s disease were differently present in the HFDm and NDm offspring groups. Our results document tight relationships between gut dysbiosis and memory and behavioural impairment in relation to maternal HFD. Persistent bacterial signatures induced by maternal HFD during infancy can influence cognition during adulthood, opening the possibility of microbiota-targeted strategies to contrast cognitive decline.

Maternal metabolic, immune, and microbial systems in late pregnancy vary with malnutrition in mice

Malnutrition is a global threat to pregnancy health and impacts offspring development. Establishing an optimal pregnancy environment requires the coordination of maternal metabolic and immune pathways, which converge at the gut. Diet, metabolic, and immune dysfunctions have been associated with gut dysbiosis in the nonpregnant individual. In pregnancy, these states are associated with poor pregnancy outcomes and offspring development. However, the impact of malnutrition on maternal gut microbes, and their relationships with maternal metabolic and immune status, has been largely underexplored. To determine the impact of undernutrition and overnutrition on maternal metabolic status, inflammation, and the microbiome, and whether relationships exist between these systems, pregnant mice were fed either a normal, calorically restricted (CR), or a high fat (HF) diet. In late pregnancy, maternal inflammatory and metabolic biomarkers were measured and the cecal microbiome was characterized. Microbial richness was reduced in HF mothers although they did not gain more weight than controls. First trimester weight gain was associated with differences in the microbiome. Microbial abundance was associated with altered plasma and gut inflammatory phenotypes and peripheral leptin levels. Taxa potentially protective against elevated maternal leptin, without the requirement of a CR diet, were identified. Suboptimal dietary conditions common during pregnancy adversely impact maternal metabolic and immune status and the microbiome. HF nutrition exerts the greatest pressures on maternal microbial dynamics and inflammation. Key gut bacteria may mediate local and peripheral inflammatory events in response to maternal nutrient and metabolic status, with implications for maternal and offspring health.

Role of dietary lipids in food allergy

The prevalence of food allergy is raising in industrialized countries, but the mechanisms behind this increased incidence are not fully understood. Environmental factors are believed to play a role in allergic diseases, including lifestyle influences, such as diet. There is a close relationship between allergens and lipids, with many allergenic proteins having the ability to bind lipids. Dietary lipids exert pro-inflammatory or anti-inflammatory functions on cells of the innate immunity and influence antigen presentation to cells of the adaptive immunity. In addition to modifying the immunostimulating properties of proteins, lipids also alter their digestibility and intestinal absorption, changing allergen bioavailability. This study provides an overview of the role of dietary lipids in food allergy, taking into account epidemiological information, as well as results of mechanistic investigations using in vivo, ex vivo and in vitro models. The emerging link among high-fat diets, obesity, and allergy is also discussed.

Early-life undernutrition reprograms CD4+ T-cell glycolysis and epigenetics to facilitate asthma

BACKGROUND

Exposure to early-life undernutrition is closely related to higher risks of adverse immunologic outcomes in adulthood. Although it has been suggested that asthma has its origins in early life, its underlying mechanisms remain largely unknown.

OBJECTIVE

We characterized the effects of early-life undernutrition on T lymphocytes, which play a pivotal role in immune diseases, and we investigated whether this contributes to susceptibility to asthma in adulthood.

METHODS

Pregnant mice were fed a protein restriction diet (PRD) to establish an early-life undernutrition model. Naive CD4⁺ T cells (CD4⁺CD62L^hiCD44^-) from offspring were used throughout the study. T_H2 differentiation was examined by using fluorescence-activated cell sorting and ELISA under T_H2-polarized conditions in vitro and through ovalbumin-induced experimental asthma in vivo. T-cell metabolism was measured with a Seahorse XF96 Analyzer. DNA methylation levels were measured by using bisulfite sequencing.

RESULTS

PRD CD4⁺ T cells displayed increased activation and proliferation and were prone to differentiate into T_H2 cells both in vitro and in vivo, leading to susceptibility to experimental asthma. Mechanistically, early-life undernutrition upregulated mechanistic target of rapamycin 1-dependent glycolysis and induced conserved noncoding DNA sequence 1 DNA hypomethylation in the T_H2 cytokine locus of CD4⁺ T cells. Glycolysis blockades undermined increased T_H2 skewing and alleviated experimental asthma in PRD mice.

CONCLUSION

Early-life undernutrition induced mechanistic target of rapamycin 1-dependent glycolysis upregulation and T_H2 cytokine locus hypomethylation in CD4⁺ T cells, resulting in increased T-cell activation, proliferation, and T_H2 skewing and further susceptibility to experimental asthma.

The effects of gut microbiota on metabolic outcomes in pregnant women and their offspring

Metabolic diseases such as gestational diabetes mellitus and obesity during pregnancy have become severe health issues due to adverse pregnant outcomes in recent years. Maternal metabolic disorders can influence the long-term health of mothers and their offspring. Current evidence demonstrated that gut microbiota plays a crucial role in metabolic dysfunction during gestation. Maternal status is associated with alterations in the compositions and diversity of the intestinal microbiota community during gestation. Antibiotic treatments may disturb the gut microbiota of pregnant women, and scientific probiotic and prebiotic supplements have positive effects on mothers and their offspring. This review discusses the role of gut microbiota on metabolic outcomes in pregnant women and their offspring, and further illustrates the impact of interventions on metabolic disorders in pregnancy. Our study may provide a novel target for health management during pregnancy.

You are what you eat: diet, health and the gut microbiota

Since the renaissance of microbiome research in the past decade, much insight has accumulated in comprehending forces shaping the architecture and functionality of resident microorganisms in the human gut. Of the multiple host-endogenous and host-exogenous factors involved, diet emerges as a pivotal determinant of gut microbiota community structure and function. By introducing dietary signals into the nexus between the host and its microbiota, nutrition sustains homeostasis or contributes to disease susceptibility. Herein, we summarize major concepts related to the effect of dietary constituents on the gut microbiota, highlighting chief principles in the diet-microbiota crosstalk. We then discuss the health benefits and detrimental consequences that the interactions between dietary and microbial factors elicit in the host. Finally, we present the promises and challenges that arise when seeking to incorporate microbiome data in dietary planning and portray the anticipated revolution that the field of nutrition is facing upon adopting these novel concepts.

Impacts of Diet and Exercise on Maternal Gut Microbiota Are Transferred to Offspring

Background: It is well established that maternal exercise during pregnancy improves metabolic outcomes associated with obesity in mothers and offspring, however, its effects on the gut microbiota of both mother and offspring, are unknown. Here, we investigated whether wheel running exercise prior to and during pregnancy and prolonged feeding of an obesogenic diet were associated with changes in the gut microbiomes of Sprague-Dawley rat dams and their offspring. Female rats were fed either chow or obesogenic diet, and half of each diet group were given access to a running wheel 10 days before mating until delivery, while others remained sedentary. 16S rRNA gene amplicon sequencing was used to assess gut microbial communities in dams and their male and female offspring around the time of weaning. Results: Statistical analyses at the operational taxonomic unit (OTU) level revealed that maternal obesogenic diet decreased gut microbial alpha diversity and altered abundances of bacterial taxa previously associated with obesity such as Bacteroides and Blautia in dams, and their offspring of both sexes. Distance based linear modeling revealed that the relative abundances of Bacteroides OTUs were associated with adiposity measures in both dams and offspring. We identified no marked effects of maternal exercise on the gut microbiota of obesogenic diet dams or their offspring. In contrast, maternal exercise decreased gut microbial alpha diversity and altered the abundance of 88 microbial taxa in offspring of control dams. Thirty of these taxa were altered in a similar direction in offspring of sedentary obesogenic vs. control diet dams. In particular, the relative abundances of Oscillibacter OTUs were decreased in offspring of both exercised control dams and sedentary obesogenic diet dams, and associated with blood glucose concentrations and adiposity measures. Analyses of predicted bacterial metabolic pathways inferred decreased indole alkaloid biosynthesis in offspring of both obesogenic diet and exercised control dams. Conclusions: Our data suggest that maternal exercise prior to and during pregnancy resulted in gut dysbiosis in offspring of control dams. Importantly, alterations in the maternal gut microbiota by obesogenic diet or obesity were transferred to their offspring.

Maternal High Fat Diet Alters Gut Microbiota of Offspring and Exacerbates DSS-Induced Colitis in Adulthood

Background: Accumulating evidence shows that high fat diet is closely associated with inflammatory bowel disease. However, the effects and underlying mechanisms of maternal high fat diet (MHFD) on the susceptibility of offspring to colitis in adulthood lacks confirmation.

Methods: C57BL/6 pregnant mice were given either a high fat (60 E% fat, MHFD group) or control diet [10 E% fat, maternal control diet (MCD) group] during gestation and lactation. The intestinal development, mucosal barrier function, microbiota, and mucosal inflammation of 3-week old offspring were assessed. After weaning all mice were fed a control diet until 8 weeks of age when the microbiota was analyzed. Offspring were also treated with 2% DSS solution for 5 days and the severity of colitis was assessed.

Results: The offspring in MHFD group were significantly heavier than those in MCD group only at 2–4 weeks of age, while no differences were found in the body weight between two groups at other measured time points. Compared with MCD group, MHFD significantly inhibited intestinal development and disrupted barrier function in 3-week old offspring. Although H&E staining showed no obvious microscopic inflammation in both groups of 3-week old offspring, increased production of inflammatory cytokines indicated low-grade inflammation was induced in MHFD group. Moreover, fecal analysis of the 3-week old offspring indicated that the microbiota compositions and diversity were significantly changed in MHFD group. Interestingly after 5 weeks consumption of control diet in both groups, the microbiota composition of offspring in MHFD group was still different from that in MCD group, although the bacterial diversity was partly recovered at 8 weeks of age. Finally, after DSS treatment in 8-week old offspring, MHFD significantly exacerbated the severity of colitis and increased the production of proinflammatory cytokine.

Conclusions: Our data reveal that MHFD in early life can inhibit intestinal development, induce dysbiosis and low-grade inflammation and lead to the disruption of intestinal mucosal barrier in offspring, and enhance DSS-induced colitis in adulthood.

Developmental Programming of Obesity and Diabetes in Mouse, Monkey, and Man in 2018: Where Are We Headed?

Childhood obesity and its comorbidities continue to accelerate across the globe. Two-thirds of pregnant women are obese/overweight, as are 20% of preschoolers. Gestational diabetes mellitus (GDM) is escalating, affecting up to 1 in 5 pregnant women. The field of developmental origins of health and disease has begun to move beyond associations to potential causal mechanisms for developmental programming. Evidence across species compellingly demonstrates that maternal obesity, diabetes, and Western-style diets create a long-lasting signature on multiple systems, including infant stem cells, the early immune system, and gut microbiota. Such exposures accelerate adipogenesis, disrupt mitochondrial metabolism, and impair energy sensing, affecting neurodevelopment, liver, pancreas, and skeletal muscle. Attempts to prevent developmental programming have met with very limited success. A challenging level of complexity is involved in how the host genome, metabolome, and microbiome throughout pregnancy and lactation increase the offspring's risk of metabolic diseases across the life span. Considerable gaps in knowledge include the timing of exposure(s) and permanence or plasticity of the response, encompassing effects from both maternal and paternal dysmetabolism. Basic, translational, and human intervention studies targeting pathways that connect diet, microbiota, and metabolism in mothers with obesity/GDM and their infants are a critical unmet need and present new challenges for disease prevention in the next generation.

The Impact of Diet on Immunity and Respiratory Diseases

The Western world has witnessed a tremendous increase in the occurrence of allergy and autoimmunity in the second half of the 20th century. Extensive efforts have been made to explain this phenomenon and various hypotheses have been formulated. Among them, two concepts have attracted the most attention: the "hygiene hypothesis," identifying the reduced exposure to environmental microorganisms as a driving force behind the observed epidemiological trends; and the "diet hypotheses," pointing to the importance of changes in our dietary habits. In this review, we discuss the interplay between the Western diet, microbiota, and inflammatory conditions, with particular emphasis on respiratory diseases. This is followed by an in-depth overview of the immunomodulatory potential of different dietary fatty acids. We conclude by identifying the outstanding questions, which, if answered, could shed further light on the impact of dietary habits on immunity and interconnect it with postulates proposed by the hygiene hypothesis. Linking these two concepts will be an important step towards understanding how Western lifestyle shapes disease susceptibility.

Disruption of maternal gut microbiota during gestation alters offspring microbiota and immunity

BACKGROUND

Early life microbiota is an important determinant of immune and metabolic development and may have lasting consequences. The maternal gut microbiota during pregnancy or breastfeeding is important for defining infant gut microbiota. We hypothesized that maternal gut microbiota during pregnancy and breastfeeding is a critical determinant of infant immunity. To test this, pregnant BALB/c dams were fed vancomycin for 5 days prior to delivery (gestation; Mg), 14 days postpartum during nursing (Mn), or during gestation and nursing (Mgn), or no vancomycin (Mc). We analyzed adaptive immunity and gut microbiota in dams and pups at various times after delivery.

RESULTS

In addition to direct alterations to maternal gut microbial composition, pup gut microbiota displayed lower α-diversity and distinct community clusters according to timing of maternal vancomycin. Vancomycin was undetectable in maternal and offspring sera, therefore the observed changes in the microbiota of stomach contents (as a proxy for breastmilk) and pup gut signify an indirect mechanism through which maternal intestinal microbiota influences extra-intestinal and neonatal commensal colonization. These effects on microbiota influenced both maternal and offspring immunity. Maternal immunity was altered, as demonstrated by significantly higher levels of both total IgG and IgM in Mgn and Mn breastmilk when compared to Mc. In pups, lymphocyte numbers in the spleens of Pg and Pn were significantly increased compared to Pc. This increase in cellularity was in part attributable to elevated numbers of both CD4+ T cells and B cells, most notable Follicular B cells.

CONCLUSION

Our results indicate that perturbations to maternal gut microbiota dictate neonatal adaptive immunity.

Maternal omega-3 fatty acids regulate offspring obesity through persistent modulation of gut microbiota

BACKGROUND

The early-life gut microbiota plays a critical role in host metabolism in later life. However, little is known about how the fatty acid profile of the maternal diet during gestation and lactation influences the development of the offspring gut microbiota and subsequent metabolic health outcomes.

RESULTS

Here, using a unique transgenic model, we report that maternal endogenous n-3 polyunsaturated fatty acid (PUFA) production during gestation or lactation significantly reduces weight gain and markers of metabolic disruption in male murine offspring fed a high-fat diet. However, maternal fatty acid status appeared to have no significant effect on weight gain in female offspring. The metabolic phenotypes in male offspring appeared to be mediated by comprehensive restructuring of gut microbiota composition. Reduced maternal n-3 PUFA exposure led to significantly depleted Epsilonproteobacteria, Bacteroides, and Akkermansia and higher relative abundance of Clostridia. Interestingly, offspring metabolism and microbiota composition were more profoundly influenced by the maternal fatty acid profile during lactation than in utero. Furthermore, the maternal fatty acid profile appeared to have a long-lasting effect on offspring microbiota composition and function that persisted into adulthood after life-long high-fat diet feeding.

CONCLUSIONS

Our data provide novel evidence that weight gain and metabolic dysfunction in adulthood is mediated by maternal fatty acid status through long-lasting restructuring of the gut microbiota. These results have important implications for understanding the interaction between modern Western diets, metabolic health, and the intestinal microbiome.

A gut feeling: Microbiome-brain-immune interactions modulate social and affective behaviors

The expression of a wide range of social and affective behaviors, including aggression and investigation, as well as anxiety- and depressive-like behaviors, involves interactions among many different physiological systems, including the neuroendocrine and immune systems. Recent work suggests that the gut microbiome may also play a critical role in modulating behavior and likely functions as an important integrator across physiological systems. Microbes within the gut may communicate with the brain via both neural and humoral pathways, providing numerous avenues of research in the area of the gut-brain axis. We are now just beginning to understand the intricate relationships among the brain, microbiome, and immune system and how they work in concert to influence behavior. The effects of different forms of experience (e.g., changes in diet, immune challenge, and psychological stress) on the brain, gut microbiome, and the immune system have often been studied independently. Though because these systems do not work in isolation, it is essential to shift our focus to the connections among them as we move forward in our investigations of the gut-brain axis, the shaping of behavioral phenotypes, and the possible clinical implications of these interactions. This review summarizes the recent progress the field has made in understanding the important role the gut microbiome plays in the modulation of social and affective behaviors, as well as some of the intricate mechanisms by which the microbiome may be communicating with the brain and immune system.

Intake of Bifidobacterium longum and Fructo-oligosaccharides prevents Colorectal Carcinogenesis

INTRODUCTION

We aimed to investigate the effects of intake of yogurt containing Bifidobacterium longum (BB536-y) and fructo-oligosaccharides (FOS) in preventing colorectal carcinogenesis in healthy subjects, and the preventive effects of short-chain fatty acids (SCFA), whose production was enhanced by the intake of BB536-y and FOS, in human colon cancer cell lines.

MATERIALS AND METHODS

The subjects were 27 healthy persons who were divided into a group taking yogurt containing BB536 (BB536-y group; n = 14) and a group taking yogurt containing BB536 and FOS (BB536-y with FOS group; n = 13) once a day for 5 weeks. The feces were sampled before and after the intake to analyze the amount of SCFA in the feces and the profile of intestinal flora, such as putrefactive bacteria and Bacteroides fragilis enterotoxin (ETBF). Subsequently, human colon cancer cell lines (DLD-1 cells, WirDr cells) were cultured in the presence of SCFA (butyric acid, isobutyric acid, acetic acid) in order to evaluate the cell growth-inhibitory activity of SCFA (WST-8 assay) by calculating the IC50 value from the dose-response curve.

RESULTS

Intake of BB536-y increased the total amount of SCFA in the feces and significantly suppressed the detection rate of ETBF and growth of putrefactive bacteria. Intake of BB536-y with FOS was associated with a higher Bifidobacterium detection rate than that of BB536-y alone. The contents of butyric acid, isobutyric acid, and acetic acid, namely, of SCFA, were also decreased. Analysis of the results of culture of DLD-1 cells and WirDr cells in the presence of butyric acid, isobutyric acid, and acetic acid revealed that each of the substances showed significant cell growth-inhibitory activity, with the activity being the highest for butyric acid, followed by that for isobutyric acid and acetic acid.

CONCLUSION

These findings suggest that intake of both BB536-y and BB536-y with FOS prevents colorectal carcinogenesis.How to cite this article: Ohara T, Suzutani T. Intake of Bifidobacterium longum and Fructo-oligosaccharides prevents Colorectal Carcinogenesis. Euroasian J Hepato-Gastroenterol 2018;8(1):11-17.

Maternal high fat diet and its consequence on the gut microbiome: A rat model

The biological changes that occur during pregnancy in the female mammal include shifts in hormonal regulation in preparation for parturition and lactation, and changes in energy metabolism. In women, studies have also shown that during pregnancy there is a reduction in bacterial species richness in the gut. In the current experiment rats were used to model the interaction of diet, reproductive status, and intestinal bacterial microbiota during pregnancy and lactation. In Experiment 1 rats were exposed to either standard chow or high-fat chow (60%) and were divided into two groups: unmated (NULL) or mated (RE). In Experiment 2, both NULL and RE rats were exposed to high-fat chow for a 30-day period. High-throughput sequencing of the 16S rRNA gene revealed that pregnancy impacted the gut microbiota in a similar manner to humans. The impact of reproductive status on microbiota composition, however, was stronger in rats fed a high-fat (HF) diet. Diet-induced changes replicated some of the changes observed in humans, such as increasing the Firmicutes/Bacteroidetes ratio. However, in contrast to humans, pregnancy in rats did not increase β-diversity between microbiota from different animals. These results indicate that during pregnancy in rats, the gut microbiota is altered in a similar manner to that which occurs in women, and that these changes are further exaggerated by exposure to a HF diet. Thus, the rat may allow modelling the effects of consumption of HF food during pregnancy and enable future studies to determine the risks of HF diets during pregnancy and its consequences on the offspring.

Deficiency of essential dietary n-3 PUFA disrupts the caecal microbiome and metabolome in mice

n-3 PUFA are lipids that play crucial roles in immune-regulation, cardio-protection and neurodevelopment. However, little is known about the role that these essential dietary fats play in modulating caecal microbiota composition and the subsequent production of functional metabolites. To investigate this, female C57BL/6 mice were assigned to one of three diets (control (CON), n-3 supplemented (n3+) or n-3 deficient (n3-)) during gestation, following which their male offspring were continued on the same diets for 12 weeks. Caecal content of mothers and offspring were collected for 16S sequencing and metabolic phenotyping. n3- male offspring displayed significantly less % fat mass than n3+ and CON. n-3 Status also induced a number of changes to gut microbiota composition such that n3- offspring had greater abundance of Tenericutes, Anaeroplasma and Coriobacteriaceae. Metabolomics analysis revealed an increase in caecal metabolites involved in energy metabolism in n3+ including α-ketoglutaric acid, malic acid and fumaric acid. n3- animals displayed significantly reduced acetate, butyrate and total caecal SCFA production. These results demonstrate that dietary n-3 PUFA regulate gut microbiota homoeostasis whereby n-3 deficiency may induce a state of disturbance. Further studies are warranted to examine whether these microbial and metabolic disturbances are causally related to changes in metabolic health outcomes.

Maternal Pregravid Obesity Remodels the DNA Methylation Landscape of Cord Blood Monocytes Disrupting Their Inflammatory Program

Prepregnancy maternal obesity is associated with adverse outcomes for the offspring, including increased incidence of neonatal bacterial sepsis and necrotizing enterocolitis. We recently reported that umbilical cord blood (UCB) monocytes from babies born to obese mothers generate a reduced IL-6/TNF-α response to TLR 1/2 and 4 ligands compared to those collected from lean mothers. These observations suggest altered development of the offspring's immune system, which in turn results in dysregulated function. We therefore investigated transcriptional and epigenetic differences within UCB monocytes stratified by prepregnancy maternal body mass index. We show that UCB monocytes from babies born to obese mothers generate a dampened response to LPS stimulation compared with those born to lean mothers, at the level of secreted immune mediators and transcription. Because gene expression profiles of resting UCB monocytes from both groups were comparable, we next investigated the role of epigenetic differences. Indeed, we detected stark differences in methylation levels within promoters and regulatory regions of genes involved in TLR signaling in resting UCB monocytes. Interestingly, the DNA methylation status of resting cells was highly predictive of transcriptional changes post-LPS stimulation, suggesting that cytosine methylation is one of the dominant mechanisms driving functional inadequacy in UCB monocytes obtained from babies born to obese mothers. These data highlight a potentially critical role of maternal pregravid obesity-associated epigenetic changes in influencing the function of an offspring's monocytes at birth. These findings further our understanding of mechanisms that explain the increased risk of infection in neonates born to mothers with high prepregnancy body mass index.

Maternal modifiers of the infant gut microbiota: metabolic consequences

Transmission of metabolic diseases from mother to child is multifactorial and includes genetic, epigenetic and environmental influences. Evidence in rodents, humans and non-human primates support the scientific premise that exposure to maternal obesity or high-fat diet during pregnancy creates a long-lasting metabolic signature on the infant innate immune system and the juvenile microbiota, which predisposes the offspring to obesity and metabolic diseases. In neonates, gastrointestinal microbes introduced through the mother are noted for their ability to serve as direct inducers/regulators of the infant immune system. Neonates have a limited capacity to initiate an immune response. Thus, disruption of microbial colonization during the early neonatal period results in disrupted postnatal immune responses that highlight the neonatal period as a critical developmental window. Although the mechanisms are poorly understood, increasing evidence suggests that maternal obesity or poor diet influences the development and modulation of the infant liver and other end organs through direct communication via the portal system, metabolite production, alterations in gut barrier integrity and the hematopoietic immune cell axis. This review will focus on how maternal obesity and dietary intake influence the composition of the infant gut microbiota and how an imbalance or maladaptation in the microbiota, including changes in early pioneering microbes, might contribute to the programming of offspring metabolism with special emphasis on mechanisms that promote chronic inflammation in the liver. Comprehension of these pathways and mechanisms will elucidate our understanding of developmental programming and may expand the avenue of opportunities for novel therapeutics.

Maternal treatment with short-chain fatty acids modulates the intestinal microbiota and immunity and ameliorates type 1 diabetes in the offspring

We recently hypothesized that the intestinal microbiota and the innate immune system play key roles in the mechanism of Kilham Rat Virus-induced type 1 diabetes in the LEW1.WR1 rat. We used this animal model to test the hypothesis that maternal therapy with short-chain fatty acids can modulate the intestinal microbiota and reverse virus-induced proinflammatory responses and type 1 diabetes in rat offspring. We observed that administration of short-chain fatty acids to rat breeders via drinking water prior to pregnancy and further treatment of the offspring with short-chain fatty acids after weaning led to disease amelioration. In contrast, rats that were administered short-chain fatty acids beginning at weaning were not protected from type 1 diabetes. Short-chain fatty acid therapy exerted a profound effect on the intestinal microbiome in the offspring reflected by a reduction and an increase in the abundances of Firmicutes and Bacteroidetes taxa, respectively, on day 5 post-infection, and reversed virus-induced alterations in certain bacterial taxa. Principal component analysis and permutation multivariate analysis of variance tests further revealed that short-chain fatty acids induce a distinct intestinal microbiota compared with uninfected animals or rats that receive the virus only. Short-chain fatty acids downregulated Kilham Rat Virus-induced proinflammatory responses in the intestine. Finally, short-chain fatty acids altered the B and T cell compartments in Peyer’s patches. These data demonstrate that short-chain fatty acids can reshape the intestinal microbiota and prevent virus-induced islet autoimmunity and may therefore represent a useful therapeutic strategy for disease prevention.

The prenatal gut microbiome: are we colonized with bacteria in utero?

The colonization of the gut with microbes in early life is critical to the developing newborn immune system, metabolic function and potentially future health. Maternal microbes are transmitted to offspring during childbirth, representing a key step in the colonization of the infant gut. Studies of infant meconium suggest that bacteria are present in the foetal gut prior to birth, meaning that colonization could occur prenatally. Animal studies have shown that prenatal transmission of microbes to the foetus is possible, and physiological changes observed in pregnant mothers indicate that in utero transfer is likely in humans as well. However, direct evidence of in utero transfer of bacteria in humans is lacking. Understanding the timing and mechanisms involved in the first colonization of the human gut is critical to a comprehensive understanding of the early life gut microbiome. This review will discuss the evidence supporting in utero transmission of microbes from mother to infants. We also review sources of transferred bacteria, physiological mechanisms of transfer and modifiers of maternal microbiomes and their potential role in early life infant health. Well-designed longitudinal birth studies that account for established modifiers of the gut microbiome are challenging, but will be necessary to confirm in utero transfer and further our knowledge of the prenatal microbiome.

Association of Childhood Obesity and the Immune System: A Systematic Review of Reviews

The growing prevalence of childhood obesity has become a serious health problem over the past decades. As the immune system is greatly affected by excess weight, in this review of reviews, we discuss the findings of review articles about the relationship between childhood/maternal obesity and children's immune system. We searched English-language articles in PubMed, Scopus, ISI Thomson Reuters, and Google Scholar databases. All relevant reviews, either systematic or narrative, were retrieved. Then their quality was assessed by using the Assessment of Multiple Systematic Reviews and International Narrative Systematic Assessment tools, respectively. In the final step, 26 reviews were included. Our review suggests that childhood obesity is associated with extensive changes in the serum levels of inflammatory and anti-inflammatory cytokines and proteins, as well as the number of immune cells and their behavior. Therefore, it might cause or exacerbate diseases such as asthma, allergy, atopic dermatitis (AD), and obstructive sleep apnea syndrome. Moreover, childhood obesity may reduce the immune system responsiveness to vaccines and microorganisms. Furthermore, studies suggest that maternal obesity increases the risk of asthma in offspring. Future studies are needed to determine different associations of childhood obesity with allergy, atophic dermatitis, and autoimmune diseases.

Diet Hypotheses in Light of the Microbiota Revolution: New Perspectives

From an evolutionary standpoint, allergy has only recently emerged as a significant health problem. Various hypotheses were proposed to explain this, but they all indicated the importance of rapid lifestyle changes, which occurred in industrialized countries in the last few decades. In this review, we discuss evidence from epidemiological and experimental studies that indicate changes in dietary habits may have played an important role in this phenomenon. Based on the example of dietary fiber, we discuss molecular mechanisms behind this and point towards the importance of diet-induced changes in the microbiota. Finally, we reason that future studies unraveling mechanisms governing these changes, along with the development of better tools to manipulate microbiota composition in individuals will be crucial for the design of novel strategies to combat numerous inflammatory disorders, including atopic diseases.

Maternal obese-type gut microbiota differentially impact cognition, anxiety and compulsive behavior in male and female offspring in mice

Maternal obesity is known to predispose offspring to metabolic and neurodevelopmental abnormalities. While the mechanisms underlying these phenomena are unclear, high fat diets dramatically alter intestinal microbiota, and gut microbiota can impact physiological function. To determine if maternal diet-induced gut dysbiosis can disrupt offspring neurobehavioral function, we transplanted high fat diet- (HFD) or control low fat diet-associated (CD) gut microbiota to conventionally-housed female mice. Recipient mice were then bred and the behavioral phenotype of male and female offspring was tracked. While maternal behavior was unaffected, neonatal offspring from HFD dams vocalized less upon maternal separation than pups from CD dams. Furthermore, weaned male offspring from HFD dams had significant and selective disruptions in exploratory, cognitive, and stereotypical/compulsive behavior compared to male offspring from CD dams; while female offspring from HFD dams had increases in body weight and adiposity. 16S metagenomic analyses confirmed establishment of divergent microbiota in CD and HFD dams, with alterations in diversity and taxonomic distribution throughout pregnancy and lactation. Likewise, significant alterations in gut microbial diversity and distribution were noted in offspring from HFD dams compared to CD dams, and in males compared to females. Regression analyses of behavioral performance against differentially represented taxa suggest that decreased representation of specific members of the Firmicutes phylum predict behavioral decline in male offspring. Collectively, these data establish that high fat diet-induced maternal dysbiosis is sufficient to disrupt behavioral function in murine offspring in a sex-specific manner. Thus these data reinforce the essential link between maternal diet and neurologic programming in offspring and suggest that intestinal dysbiosis could link unhealthy modern diets to the increased prevalence of neurodevelopmental and childhood disorders.

The Role of the Immune System in Metabolic Health and Disease

In addition to the immune system's traditional roles of conferring anti-infectious and anti-neoplastic protection, it has been recently implicated in the regulation of systemic metabolic homeostasis. This cross-talk between the immune and the metabolic systems is pivotal in promoting "metabolic health" throughout the life of an organism and plays fundamental roles in its adaptation to ever-changing environmental makeups and nutritional availability. Perturbations in this intricate immune-metabolic cross-talk contribute to the tendency to develop altered metabolic states that may culminate in metabolic disorders such as malnutrition, obesity, type 2 diabetes mellitus (T2DM), and other features of the metabolic syndrome. Regulators of immune-metabolic interactions include host genetics, nutritional status, and the intestinal microbiome. In this Perspective, we highlight current understanding of immune-metabolism interactions, illustrate differences among individuals and between populations in this respect, and point toward future avenues of research possibly enabling immune harnessing as means of personalized treatment for common metabolic disorders.