Transcription shifts in gut bacteria shared between mothers and their infants

The impact of gestational diabetes on functional capacity of the infant gut microbiome is modest and transient

Gestational diabetes mellitus (GDM) is a metabolic complication that manifests as hyperglycemia during the later stages of pregnancy. In high resource settings, careful management of GDM limits risk to the pregnancy, and hyperglycemia typically resolves after birth. At the same time, previous studies have revealed that the gut microbiome of infants born to mothers who experienced GDM exhibit reduced diversity and reduction in the abundance of several key taxa, including Lactobacillus. What is not known is what the functional consequences of these changes might be. In this case control study, we applied 16S rRNA sequence surveys and metatranscriptomics to profile the gut microbiome of 30 twelve-month-old infants - 16 from mothers with GDM, 14 from mothers without - to examine the impact of GDM during pregnancy. Relative to the mode of delivery and sex of the infant, maternal GDM status had a limited impact on the structure and function of the developing microbiome. While GDM samples were associated with a decrease in alpha diversity, we observed no effect on beta diversity and no differentially abundant taxa. Further, while the mode of delivery and sex of infant affected the expression of multiple bacterial pathways, much of the impact of GDM status on the function of the infant microbiome appears to be lost by twelve months of age. These data may indicate that, while mode of delivery appears to impact function and diversity for longer than anticipated, GDM may not have persistent effects on the function nor composition of the infant gut microbiome.

Understanding human health through metatranscriptomics

Metatranscriptomics has revolutionized our ability to explore and understand transcriptional programs in microbial communities. Moreover, it has enabled us to gain deeper and more specific insight into the microbial activities in human gut, respiratory, oral, and vaginal communities. Perhaps the most important contribution of metatranscriptomics arises, however, from the analyses of disease-associated communities. We review the advantages and disadvantages of metatranscriptomics analyses in understanding human health and disease. We focus on human tissues low in microbial biomass and conditions associated with dysbiotic microbiota. We conclude that a more widespread use of metatranscriptomics and increased knowledge on microbe activities will uncover critical interactions between microbes and host in human health and provide diagnostic basis for culturing-independent, direct functional pathogen identification.

A narrative review of the functional components of human breast milk and their potential to modulate the gut microbiome, the consideration of maternal and child characteristics, and confounders of breastfeeding, and their impact on risk of obesity later in life

Nutritional exposure and, therefore, the metabolic environment during early human development can affect health later in life. This can go beyond the nutrients consumed; there is evidence that the development and modulation of the gut microbiome during early life can affect human growth, development, and health, and the gut microbiome is associated with the risk of obesity later in life. The primary aim of this review was to evaluate existing evidence, to identify the components of human breast milk, which may modulate the gut microbiome, and to assess the impact of the gut microbiome on the risk of becoming obese later in life. This review also considers maternal and child characteristics, and confounders of breastfeeding and how they impact on the infant gut microbiome. Current evidence supports a positive association between fecal, branched short-chain fatty acids and human milk oligosaccharide diversity and a gut microbiome associated with better metabolic health. A negative correlation was found between microbiome diversity and human milk oligosaccharide evenness, which was associated with a greater fat mass and percentage of fat. The components of human breast milk, including oligosaccharides, probiotics, milk fat globule membrane, and adiponectin, were hypothesized to positively influence infant growth and body weight by modulating the microbial diversity and composition of the gut. Maternal diet, timing and duration of breast feeding, and the mode of delivery were all shown to affect the human milk microbiota. However, more experimental studies with long follow-up are required to shed light on the governing mechanisms linking breast milk components with a diverse infant microbiome and healthier body weight later in life.

Maternal weight and gestational diabetes impacts on child health

PURPOSE OF REVIEW

To review recent evidence linking maternal body mass index and gestational diabetes mellitus (GDM) with offspring health outcomes.

RECENT FINDINGS

It is now established that the rising prevalences of maternal obesity and GDM are both making substantial contributions to the growing burden of childhood obesity and associated disorders. Strengthening evidence also links maternal obesity with increased offspring risks of cardiovascular disease, nonalcoholic fatty liver disease, lower respiratory tract infections during infancy, wheezing illnesses, asthma and attention deficit hyperactivity disorder during childhood, and with higher risks of psychiatric disorders and colorectal cancer in adulthood. GDM has been associated with increased offspring risks of cardiovascular disease, childhood wheeze/asthma (but not allergic sensitization), and with high refractive error, attention deficit hyperactivity and psychiatric disorders from childhood onwards.

SUMMARY

The long-term consequences of maternal obesity and GDM for the offspring in childhood and later adult life present major challenges for public health across the life course and for future generations. Tackling these challenges requires a systems-based approach to support achieving a healthy weight in young people prior to conception, alongside new insights into population based preventive measures against gestational diabetes.