Fetal meconium does not have a detectable microbiota before birth

Kennedy, Katherine M.; Gerlach, Max; Adam, Thomas C.; Heimesaat, Markus M.; Rossi, Laura; Surette, Michael G.; Sloboda, Deborah M.; Braun, Thorsten

doi:10.1038/s41564-021-00904-0

Cited by 126 publications

(99 citation statements)

References 53 publications

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“…In a recent study, fecal meconium was collected before antibiotic administration during breech CSDs without labor and compared to standard VDs, first-pass meconium, and stool. It was found that the bacteria in the samples were most likely skin contaminants such as Staphylococcus epidermidis [17]. On the other hand, some authors still defend the hypothesis that the sterility of the human fetal intestine is not absolute, but both the number and diversity of bacteria are very low [18,19].…”

Section: Introductionmentioning

confidence: 99%

From Short- to Long-Term Effects of C-Section Delivery on Microbiome Establishment and Host Health

2021

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The establishment of gut microbiota has been proven to be impacted by several factors during pregnancy, delivery, and neonate periods. The body of evidence describing C-section delivery (CSD) as one of the most disruptive events during early life has expanded in recent years, concluding that CSD results in a drastic change in microbiota establishment patterns. When comparing the gut microbiota composition of CSD babies with vaginally delivered (VD) babies, the former show a microbiome that closely resembles that found in the environment and the mother’s skin, while VD babies show a microbiome more similar to the vaginal microbiome. Although these alterations of normal gut microbiota establishment tend to disappear during the first months of life, they still affect host health in the mid–long term since CSD has been correlated with a higher risk of early life infections and non-transmissible diseases, such as inflammatory diseases, allergies, and metabolic diseases. In recent years, this phenomenon has also been studied in other mammals, shedding light on the mechanisms involved in the effects of a CSD on host health. In addition, strategies to revert the disruptions in gut microbiomes caused by a CSD are currently in the process of development and evaluation. In this review, we discuss the recent advances in CSD research, from the alteration of gut microbiota establishment to the possible effects on host health during early life and development.

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Section: Introductionmentioning

confidence: 99%

From Short- to Long-Term Effects of C-Section Delivery on Microbiome Establishment and Host Health

2021

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“…Although the in utero microbial colonization hypothesis is still controversial, and many support the "sterile-womb hypothesis" that infant microbiome acquisition occurs only during and after birth (Perez-Muñoz et al, 2017;de Goffau et al, 2019;Kennedy et al, 2021), very recent studies provide convincing evidence to support the former hypothesis. Rackaityte and colleagues (2020) were able to culture viable bacteria (Micrococcaceae and Lactobacillus strains) from the human fetal intestine at mid-gestation.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the microbiota associated with 12-week-old bovine fetuses exposed to divergent in utero nutrition

Amat

Holman

Schmidt

et al. 2021

Preprint

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A recent study reported the existence of a diverse microbiota in 5-to-7-month-old calf fetuses, suggesting that colonization of the bovine gut with so-called 'pioneer' microbiota may begin during mid-gestation. In the present study, we investigated 1) the presence of microbiota in bovine fetuses at early gestation (12 weeks), and 2) whether the fetal microbiota is influenced by the maternal rate of gain or dietary supplementation with vitamins and minerals (VTM) during early gestation. Amniotic and allantoic fluids, and intestinal and placental (cotyledon) tissue samples obtained from fetuses (n = 33) on day 83 of gestation were processed for the assessment of fetal microbiota using 16S rRNA gene sequencing. The sequencing results revealed that a diverse and complex microbial community was present in each of these fetal compartments evaluated. Allantoic and amniotic fluids, and fetal intestinal and placenta microbiota each had distinctly different (0.047 ≥ R2 ≥ 0.019, P ≤ 0.031) microbial community structures. Allantoic fluid had a greater (P < 0.05) microbial richness (number of OTUs) (Mean 122) compared to amniotic fluid (84), intestine (63) and placenta (66). Microbial diversity (Shannon index) was similar for the intestinal and placental samples, and both were less diverse compared with fetal fluid microbiota (P < 0.05). Thirty-nine different archaeal and bacterial phyla were detected across all fetal samples, with Proteobacteria (55%), Firmicutes (16.2%), Acidobacteriota (13.6%) and Bacteroidota (5%) predominating. Among the 20 most relatively abundant bacterial genera, Acidovorax, Acinetobacter, Brucella, Corynebacterium, Enterococcus, Exiguobacterium and Stenotrophomonas differed by fetal sample type (P < 0.05). A total of 55 taxa were shared among the four different microbial communities. qPCR of bacteria in the intestine and placenta samples as well as scanning electron microscopy imaging of fetal fluids provided additional evidence for the presence of a microbiota in these samples. Minor effects of maternal rate of gain and VTM supplementation, and their interactions on microbial richness and composition were detected. Overall, the results of this study indicate that colonization with pioneer microbiota may occur during early gestation in bovine fetuses, and that that the maternal nutritional regime during gestation may influence the early fetal microbiota.

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“…Though the timing of fetal microbiome development is highly debated, convincing evidence suggests the fetus begins developing its microbiome during birth in the mouse and human and is generally compositionally similar to the maternal microbiome (Jiménez et al, 2008;Ferretti et al, 2018;Younge et al, 2019;Kennedy et al, 2021). During early life, the microbiome is critical for postnatal innate immune development as well as microglial maturation, which could affect how microglia respond in physiological and pathological conditions in adulthood (Erny et al, 2015;Gomez de Aguero et al, 2016;Matcovitch-Natan et al, 2016;Thion et al, 2018).…”

Section: Microbiome Influences On Microglia and Astrocyte Function In Healthmentioning

confidence: 99%

Modulation of Glial Function in Health, Aging, and Neurodegenerative Disease

Hanslik

Marino

Ulland

2021

Front. Cell. Neurosci.

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In the central nervous system (CNS), glial cells, such as microglia and astrocytes, are normally associated with support roles including contributions to energy metabolism, synaptic plasticity, and ion homeostasis. In addition to providing support for neurons, microglia and astrocytes function as the resident immune cells in the brain. The glial function is impacted by multiple aspects including aging and local CNS changes caused by neurodegeneration. During aging, microglia and astrocytes display alterations in their homeostatic functions. For example, aged microglia and astrocytes exhibit impairments in the lysosome and mitochondrial function as well as in their regulation of synaptic plasticity. Recent evidence suggests that glia can also alter the pathology associated with many neurodegenerative disorders including Alzheimer’s disease (AD) and Parkinson’s disease (PD). Shifts in the microbiome can impact glial function as well. Disruptions in the microbiome can lead to aberrant microglial and astrocytic reactivity, which can contribute to an exacerbation of disease and neuronal dysfunction. In this review, we will discuss the normal physiological functions of microglia and astrocytes, summarize novel findings highlighting the role of glia in aging and neurodegenerative diseases, and examine the contribution of microglia and astrocytes to disease progression.

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Fetal meconium does not have a detectable microbiota before birth

Cited by 126 publications

References 53 publications

From Short- to Long-Term Effects of C-Section Delivery on Microbiome Establishment and Host Health

From Short- to Long-Term Effects of C-Section Delivery on Microbiome Establishment and Host Health

Characterization of the microbiota associated with 12-week-old bovine fetuses exposed to divergent in utero nutrition

Modulation of Glial Function in Health, Aging, and Neurodegenerative Disease

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