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Yu K, Rodriguez M, Paul Z, Gordon E, Gu T, Rice K, Triplett EW, Keller-Wood M, Wood CE. Transfer of oral bacteria to the fetus during late gestation. Sci Rep 2021; 11:708. [PMID: 33436911 PMCID: PMC7804304 DOI: 10.1038/s41598-020-80653-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022] Open
Abstract
The fetus develops in a privileged environment, as the placenta serves as both a gateway for nutrients and a barrier for pathogen transfer to the fetus. Regardless, recent evidence suggests the presence of bacterial DNA in both placenta and fetus, and we have reported that DNA and protein from small numbers of bacteria gain access to the fetus from the maternal bloodstream. Other routes of environmental bacterial transfer from the mother to fetus remain unknown, as well as the physiological relevance of their presence. In these experiments, we examine multiple routes by which bacterial cellular components can enter the fetus and the fetal response to influx of bacterial DNA and protein. We inoculated maternal sheep with genetically-labeled S. aureus (Staphylococcus aureus) using three routes: intravenously, orally, and intra-vaginally. The inoculum did not produce sepsis or fever in the ewes, therefore mimicking incidental exposure to bacteria during pregnancy. 3-5 days post inoculation, we assessed the presence of bacterial components in the fetal tissues and analyzed fetal brain tissue to identify any alterations in gene expression. Our results demonstrate that components of bacteria that were introduced into the maternal mouth were detected in the fetal brain and that they stimulated changes in gene expression. We conclude that an oral route of transmission is relevant for transfer of bacterial cellular components to the fetus.
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Affiliation(s)
- Kevin Yu
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1345 Center Drive, Room M552, Gainesville, FL, 32610, USA
| | - Michelle Rodriguez
- Department of Microbiology and Cell Science, University of Florida Institute of Food and Agricultural Sciences, Gainesville, USA
| | - Zubin Paul
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1345 Center Drive, Room M552, Gainesville, FL, 32610, USA
| | - Elizabeth Gordon
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1345 Center Drive, Room M552, Gainesville, FL, 32610, USA
| | - Tongjun Gu
- Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, USA
| | - Kelly Rice
- Department of Microbiology and Cell Science, University of Florida Institute of Food and Agricultural Sciences, Gainesville, USA
| | - Eric W Triplett
- Department of Microbiology and Cell Science, University of Florida Institute of Food and Agricultural Sciences, Gainesville, USA
| | - Maureen Keller-Wood
- Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, USA
| | - Charles E Wood
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, 1345 Center Drive, Room M552, Gainesville, FL, 32610, USA.
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Bennet L, Ikeda T, Llanos AJ, Nijhuis J, Gunn AJ. Challenges and controversies in perinatal physiology. J Physiol 2019; 596:5485-5489. [PMID: 30499159 DOI: 10.1113/jp276299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- L Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
| | - T Ikeda
- Department of Obstetrics and Gynaecology, Mie University, Mie Prefecture, Japan
| | - A J Llanos
- Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - J Nijhuis
- Department of Obstetrics and Gynaecology, Maastricht University, Maastricht, The Netherlands
| | - A J Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, University of Auckland, Auckland, New Zealand
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Wood CE, Keller-Wood M. Current paradigms and new perspectives on fetal hypoxia: implications for fetal brain development in late gestation. Am J Physiol Regul Integr Comp Physiol 2019; 317:R1-R13. [PMID: 31017808 DOI: 10.1152/ajpregu.00008.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The availability of oxygen to the fetus is limited by the route taken by oxygen from the atmosphere to fetal tissues, aided or diminished by pregnancy-associated changes in maternal physiology and, ultimately, a function of atmospheric pressure and composition of the mother's inspired gas. Much of our understanding of the fetal physiological response to hypoxia comes from experiments designed to elucidate the cardiovascular and endocrine responses to transient hypoxia. Complementing this work is equally impactful research into the origins of intrauterine growth restriction in which animal models designed to restrict the transfer of oxygen from the maternal to the fetal circulation were used. A common assumption has been that outcomes measured after a period of hypoxia are related to cellular deprivation of oxygen and reoxygenation: an assumption based on a focus on what we can see "under the streetlights." Recent studies demonstrate that availability of oxygen may not tell the whole story. Transient hypoxia in the fetal sheep stimulates transcriptomics responses that mirror inflammation. This response is accompanied by the appearance of bacteria in the fetal brain and other tissues, likely resulting from a hypoxia-stimulated release of bacteria from the placenta. The appearance of bacteria in the fetus after transient hypoxia complements the recent discovery of bacterial DNA in the normal human placenta and in the tissues of fetal sheep. An understanding of the mechanism of the physiological, cellular, and molecular responses to hypoxia requires an appreciation of stimuli other than cellular oxygen deprivation: stimuli that we would have never known about without looking "between the streetlights," illuminating direct responses to the manipulated variables.
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Affiliation(s)
- Charles E Wood
- Department of Physiology and Functional Genomics, University of Florida College of Medicine , Gainesville, Florida
| | - Maureen Keller-Wood
- Department of Pharmacodynamics, University of Florida College of Pharmacy , Gainesville, Florida
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