I am a scientist specialized in mitochondria and genetics, but above all, I am just curious guy who loves learning new things.
Moms are so great that even their microbes are helpful!
In 10 seconds? Gut microbiota, the ensemble of microbes that live in our intestinal tract, is established during early childhood and external factors such as the type of birth and feeding method shape its composition, with life-long consequences on health.
So before birth there are no microbes in our gut? The fetal gastrointestinal tract is believed to be sterile before birth and the first exposure to microbes normally occurs during birth, when the baby passes through the mother’s birth canal being exposed to her vaginal microbes. Recent studies show that this first contact with maternal microbes is essential for adequate bacterial colonization of the gut and immune development, and children delivered by C-section have an increased risk for immune and metabolic disorders.
And how does the feeding method influence the microbiota? Breastmilk contains live microbes, that pass on to the baby colonizing his gut, along with metabolites, antibodies, immune cells and cytokines that stimulate the growth of “good” germs in the baby’s colon and protect him from pathogens. Thereby, breastmilk facilitates the proliferation of a well-balanced and diverse microbiota that will protect the baby against infection and immune-mediated diseases, such as asthma or inflammatory bowel disease.
If microbes are that important, what about antibiotics? Antibiotics are an important piece of today’s medicine and disease prevention, but the use of antibiotics too early in life can disrupt the microbiota, having long-term effects on the immune system and brain neurochemistry, because of the fragility of a developing infant’s gut microbiota. For instance, a recent study showed that low-dose penicillin in early life has long-term consequences on gut microbiota and behavior in adult mice. And even antibiotics given to the mother during birth can affect the baby’s microbiota.
But in some cases C-sections and antibiotics are necessary. Indeed, but fortunately breastfeeding modifies some of the negative effects of these interventions, normalizing the gut microbiota after some months. Nevertheless, in some cases breastfeeding is not an option, highlighting the need to improve formula milk to better imitate the beneficial characteristics of breast milk and help formula-fed infants develop a strong and protective gut microbiota.
Abstract: There is increasing concern about potential long-term effects of antibiotics on children's health. Epidemiological studies have revealed that early-life antibiotic exposure can increase the risk of developing immune and metabolic diseases, and rodent studies have shown that administration of high doses of antibiotics has long-term effects on brain neurochemistry and behaviour. Here we investigate whether low-dose penicillin in late pregnancy and early postnatal life induces long-term effects in the offspring of mice. We find that penicillin has lasting effects in both sexes on gut microbiota, increases cytokine expression in frontal cortex, modifies blood-brain barrier integrity and alters behaviour. The antibiotic-treated mice exhibit impaired anxiety-like and social behaviours, and display aggression. Concurrent supplementation with Lactobacillus rhamnosus JB-1 prevents some of these alterations. These results warrant further studies on the potential role of early-life antibiotic use in the development of neuropsychiatric disorders, and the possible attenuation of these by beneficial bacteria.
Pub.: 05 Apr '17, Pinned: 20 Sep '17
Abstract: Exposure of newborns to the maternal vaginal microbiota is interrupted with cesarean birthing. Babies delivered by cesarean section (C-section) acquire a microbiota that differs from that of vaginally delivered infants, and C-section delivery has been associated with increased risk for immune and metabolic disorders. Here we conducted a pilot study in which infants delivered by C-section were exposed to maternal vaginal fluids at birth. Similarly to vaginally delivered babies, the gut, oral and skin bacterial communities of these newborns during the first 30 d of life was enriched in vaginal bacteria-which were underrepresented in unexposed C-section-delivered infants-and the microbiome similarity to those of vaginally delivered infants was greater in oral and skin samples than in anal samples. Although the long-term health consequences of restoring the microbiota of C-section-delivered infants remain unclear, our results demonstrate that vaginal microbes can be partially restored at birth in C-section-delivered babies.
Pub.: 02 Feb '16, Pinned: 20 Sep '17
Abstract: Dysbiosis of the infant gut microbiota may have long‐term health consequences. This study aimed to determine the impact of maternal intrapartum antibiotic prophylaxis (IAP) on infant gut microbiota, and to explore whether breastfeeding modifies these effects.Prospective pregnancy cohort of Canadian infants born in 2010–2012: the Canadian Healthy Infant Longitudinal Development (CHILD) Study.General community.Representative sub‐sample of 198 healthy term infants from the CHILD Study.Maternal IAP exposures and birth method were documented from hospital records and breastfeeding was reported by mothers. Infant gut microbiota was characterised by Illumina 16S rRNA sequencing of faecal samples at 3 and 12 months.Infant gut microbiota profiles.In this cohort, 21% of mothers received IAP for Group B Streptococcus prophylaxis or pre‐labour rupture of membranes; another 23% received IAP for elective or emergency caesarean section (CS). Infant gut microbiota community structures at 3 months differed significantly with all IAP exposures, and differences persisted to 12 months for infants delivered by emergency CS. Taxon‐specific composition also differed, with the genera Bacteroides and Parabacteroides under‐represented, and Enterococcus and Clostridium over‐represented at 3 months following maternal IAP. Microbiota differences were especially evident following IAP with emergency CS, with some changes (increased Clostridiales and decreased Bacteroidaceae) persisting to 12 months, particularly among non‐breastfed infants.Intrapartum antibiotics in caesarean and vaginal delivery are associated with infant gut microbiota dysbiosis, and breastfeeding modifies some of these effects. Further research is warranted to explore the health consequences of these associations.Maternal #antibiotics during childbirth alter the infant gut #microbiome.
Pub.: 28 Sep '15, Pinned: 20 Sep '17
Abstract: The microbial communities colonizing the human gut are tremendously diverse and highly personal. The composition and function of the microbiota play important roles in human health and disease, and considerable research has focused on understanding the ecological forces shaping these communities. While it is clear that factors such as diet, genotype of the host, and environment influence the adult gut microbiota community composition, recent work has emphasized the importance of early-life assembly dynamics in both the immediate and long-term personalized nature of the gut microbiota. While the mature adult gut microbiota is believed to be relatively stable, the developing infant gut microbiota (IGM) is highly dynamic and prone to disruption by external factors, including antibiotic exposure. Studies have revealed both transient and persistent alterations to the adult gut microbiota community resulting from antibiotic treatment later in life. As antibiotics are routinely prescribed at a greater rate in the first years of life, the impact of these interventions on the developing IGM is emerging as a key research priority. In addition to understanding the impact of these disruptions on the infant gut microbial architecture and related host diseases, we need to understand the contribution of early life antibiotics to the selection of antibiotic resistance gene reservoirs in the microbiota, and their threat to successful treatment of infectious disease. Here we review the current understanding of the developmental progression of the IGM and the impact of antibiotic therapies on its composition and encoded reservoir of antibiotic resistance genes.
Pub.: 05 Aug '15, Pinned: 20 Sep '17
Abstract: Maintenance of intestinal homeostasis requires a healthy relationship between the commensal gut microbiota and the host immune system. Breast milk supplies the first source of antigen-specific immune protection in the gastrointestinal tract of suckling mammals, in the form of secretory IgA (SIgA). SIgA is transported across glandular and mucosal epithelial cells into external secretions by the polymeric Ig receptor (pIgR). Here, a breeding scheme with polymeric Ig receptor-sufficient and -deficient mice was used to study the effects of breast milk-derived SIgA on development of the gut microbiota and host intestinal immunity. Early exposure to maternal SIgA prevented the translocation of aerobic bacteria from the neonatal gut into draining lymph nodes, including the opportunistic pathogen Ochrobactrum anthropi. By the age of weaning, mice that received maternal SIgA in breast milk had a significantly different gut microbiota from mice that did not receive SIgA, and these differences were magnified when the mice reached adulthood. Early exposure to SIgA in breast milk resulted in a pattern of intestinal epithelial cell gene expression in adult mice that differed from that of mice that were not exposed to passive SIgA, including genes associated with intestinal inflammatory diseases in humans. Maternal SIgA was also found to ameliorate colonic damage caused by the epithelial-disrupting agent dextran sulfate sodium. These findings reveal unique mechanisms through which SIgA in breast milk may promote lifelong intestinal homeostasis, and provide additional evidence for the benefits of breastfeeding.
Pub.: 27 Feb '14, Pinned: 20 Sep '17
Abstract: The microbiota plays a fundamental role on the induction, training, and function of the host immune system. In return, the immune system has largely evolved as a means to maintain the symbiotic relationship of the host with these highly diverse and evolving microbes. When operating optimally, this immune system-microbiota alliance allows the induction of protective responses to pathogens and the maintenance of regulatory pathways involved in the maintenance of tolerance to innocuous antigens. However, in high-income countries, overuse of antibiotics, changes in diet, and elimination of constitutive partners, such as nematodes, may have selected for a microbiota that lack the resilience and diversity required to establish balanced immune responses. This phenomenon is proposed to account for some of the dramatic rise in autoimmune and inflammatory disorders in parts of the world where our symbiotic relationship with the microbiota has been the most affected.
Pub.: 01 Apr '14, Pinned: 20 Sep '17
Abstract: From birth to adulthood, the gut microbiota matures from a simple community dominated by a few major bacterial groups into a highly diverse ecosystem that provides both benefits and challenges to the host. Currently there is great interest in identifying environmental and host factors that shape the development of our gut microbiota. Breast milk is a rich source of maternal antibodies, which provide the first source of adaptive immunity in the newborn's intestinal tract. In this addendum, we summarize our recent data demonstrating that maternal antibodies in breast milk promote long-term intestinal homeostasis in suckling mice by regulating the gut microbiota and host gene expression. We also discuss important unanswered questions, future directions for research in this field, and implications for human health and disease.
Pub.: 09 Dec '14, Pinned: 20 Sep '17
Abstract: The microbiota "organ" is the central bioreactor of the gastrointestinal tract, populated by a total of 10(14) bacteria and characterized by a genomic content (microbiome), which represents more than 100 times the human genome. The microbiota plays an important role in child health by acting as a barrier against pathogens and their invasion with a highly dynamic modality, exerting metabolic multistep functions and stimulating the development of the host immune system, through well-organized programming, which influences all of the growth and aging processes. The advent of "omics" technologies (genomics, proteomics, metabolomics), characterized by complex technological platforms and advanced analytical and computational procedures, has opened new avenues to the knowledge of the gut microbiota ecosystem, clarifying some aspects on the establishment of microbial communities that constitute it, their modulation and active interaction with external stimuli as well as food, within the host genetic variability. With a huge interdisciplinary effort and an interface work between basic, translational, and clinical research, microbiologists, specialists in "-omics" disciplines, and clinicians are now clarifying the role of the microbiota in the programming process of several gut-related diseases, from the physiological symbiosis to the microbial dysbiosis stage, through an integrated systems biology approach.
Pub.: 16 Apr '14, Pinned: 20 Sep '17
Abstract: Breast milk contains a rich microbiota composed of viable skin and non-skin bacteria. The extent of the breast milk microbiota diversity has been revealed through new culture-independent studies using microbial DNA signatures. However, the extent to which the breast milk microbiota are transferred from mother to infant and the function of these breast milk microbiota for the infant are only partially understood. Here, we appraise hypotheses regarding the formation of breast milk microbiota, including retrograde infant-to-mother transfer and enteromammary trafficking, and we review current knowledge of mechanisms determining the extent of breast milk microbiota transfer from mother to infant. We highlight known functions of constituents in the breast milk microbiota-to enhance immunity, liberate nutrients, synergize with breast milk oligosaccharides to enhance intestinal barrier function, and strengthen a functional gut-brain axis. We also consider the pathophysiology of maternal mastitis with respect to a dysbiosis or abnormal shift in the breast milk microbiota. In conclusion, through a complex, highly evolved process in the early stages of discovery, mothers transfer the breast milk microbiota to their infants to impact infant growth and development.
Pub.: 07 Jan '14, Pinned: 20 Sep '17
Abstract: Newborns adjust to the extrauterine environment by developing intestinal immune homeostasis. Appropriate initial bacterial colonization is necessary for adequate intestinal immune development. An environmental determinant of adequate colonization is breast milk. Although the full-term infant is developmentally capable of mounting an immune response, the effector immune component requires bacterial stimulation. Breast milk stimulates the proliferation of a well-balanced and diverse microbiota, which initially influences a switch from an intrauterine TH2 predominant to a TH1/TH2 balanced response and with activation of T-regulatory cells by breast milk-stimulated specific organisms (Bifidobacteria, Lactobacillus, and Bacteroides). As an example of its effect, oligosaccharides in breast milk are fermented by colonic bacteria producing an acid milieu for bacterial proliferation. In addition, short-chain fatty acids in breast milk activate receptors on T-reg cells and bacterial genes, which preferentially mediate intestinal tight junction expression and anti-inflammation. Other components of breast milk (defensins, lactoferrin, etc.) inhibit pathogens and further contribute to microbiota composition. The breast milk influence on initial intestinal microbiota also prevents expression of immune-mediated diseases (asthma, inflammatory bowel disease, type 1 diabetes) later in life through a balanced initial immune response, underscoring the necessity of breastfeeding as the first source of nutrition.
Pub.: 14 Oct '14, Pinned: 20 Sep '17