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Scott AK, Fodera DM, Yang P, Arter A, Hines AM, Kolluru SS, Zambuto SG, Myers KM, Kamilov US, Odibo AO, Oyen ML. Bioengineering approaches for patient-specific analysis of placenta structure and function. Placenta 2024:S0143-4004(24)00615-5. [PMID: 39153938 DOI: 10.1016/j.placenta.2024.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 07/30/2024] [Accepted: 08/06/2024] [Indexed: 08/19/2024]
Abstract
The leading cause of perinatal mortality is fetal growth restriction (FGR), defined as in utero fetal growth below the 10th percentile. Insufficient exchange of oxygen and nutrients at the maternal-fetal interface is associated with FGR. This transport occurs through the vasculature of the placenta, particularly in the terminal villi, where the vascular membranes have a large surface area and are the thinnest. Altered structure of the placenta villi is thought to contribute to decreased oxygen exchange efficiency, however, understanding how the three-dimensional microstructure and properties decrease this efficiency remains a challenge. Here, a novel, multiscale workflow is presented to quantify patient-specific biophysical properties, 3D structural features, and blood flow of the villous tissue. Namely, nanoindentation, optical coherence tomography, and ultrasound imaging were employed to measure the time-dependent material properties of placenta tissue, the 3D structure of villous tissue, and blood flow through the villi to characterize the microvasculature of the placenta at increasing length scales. Quantifying the biophysical properties, the 3D architecture, and blood flow in the villous tissue can be used to infer changes in maternal-fetal oxygen transport at the villous membrane. Overall, this multiscale understanding will advance knowledge of how microvascular changes in the placenta ultimately lead to FGR, opening opportunities for diagnosis and intervention.
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Affiliation(s)
- Adrienne K Scott
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Women's Health Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Regenerative Medicine, Washington University in St. Louis, St. Louis MO, USA
| | - Daniella M Fodera
- Department of Biomedical Engineering, Columbia University, New York NY, USA
| | - Patrick Yang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Women's Health Engineering, Washington University in St. Louis, St. Louis MO, USA
| | - Abigail Arter
- Department of Obstetrics and Gynecology, Washington University School of Medicine in St. Louis, St. Louis MO, USA
| | - Amelia M Hines
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Women's Health Engineering, Washington University in St. Louis, St. Louis MO, USA
| | - Samyuktha S Kolluru
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Women's Health Engineering, Washington University in St. Louis, St. Louis MO, USA
| | - Samantha G Zambuto
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Women's Health Engineering, Washington University in St. Louis, St. Louis MO, USA; Department of Obstetrics and Gynecology, Washington University School of Medicine in St. Louis, St. Louis MO, USA
| | - Kristin M Myers
- Department of Mechanical Engineering, Columbia University, New York NY, USA
| | - Ulugbek S Kamilov
- Department of Computer Science & Engineering, Washington University in St. Louis, St. Louis MO, USA; Department of Electrical & Systems Engineering, Washington University in St. Louis, St. Louis MO, USA
| | - Anthony O Odibo
- Department of Obstetrics and Gynecology, Washington University School of Medicine in St. Louis, St. Louis MO, USA
| | - Michelle L Oyen
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Women's Health Engineering, Washington University in St. Louis, St. Louis MO, USA; Center for Regenerative Medicine, Washington University in St. Louis, St. Louis MO, USA; Department of Obstetrics and Gynecology, Washington University School of Medicine in St. Louis, St. Louis MO, USA.
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2
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Roberts JM. Preeclampsia epidemiology(ies) and pathophysiology(ies). Best Pract Res Clin Obstet Gynaecol 2024; 94:102480. [PMID: 38490067 DOI: 10.1016/j.bpobgyn.2024.102480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/14/2023] [Accepted: 02/05/2024] [Indexed: 03/17/2024]
Abstract
Preeclampsia/eclampsia was first described 2000 years ago. Concepts guiding diagnosis have changed over time making longitudinal studies challenging. Similarly, concepts of pathophysiology have evolved from eclampsia as a pregnancy seizure disorder to preeclampsia as a hypertensive and renal disorder to our current concept of a preeclampsia as a pregnancy specific, multisystemic inflammatory disorder. Although preeclampsia is pregnancy specific and many pathophysiologic findings begin to resolve with delivery, its impact extends beyond pregnancy. The risk of cardiovascular and neurological disease is increased after pregnancy in women who have had preeclampsia. The disorder is not a disease, but a syndrome and emerging data indicate multiple pathways to the syndrome. It is likely that our failure to have a major impact on prediction and prevention despite a large increase in understanding is due to the existence of multiple subtypes of preeclampsia. This concept should guide future research.
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Affiliation(s)
- James M Roberts
- Obstetrics Gynecology and Reproductive Sciences, Epidemiology and Clinical and Translational Research University of Pittsburgh, 10 Georgian Place, Pittsburgh, PA, 15215, United States.
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3
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Scioscia M, Siwetz M, Robillard PY, Brizzi A, Huppertz B. Placenta and maternal endothelium during preeclampsia: Disruption of the glycocalyx explains increased inositol phosphoglycans and angiogenic factors in maternal blood. J Reprod Immunol 2023; 160:104161. [PMID: 37857160 DOI: 10.1016/j.jri.2023.104161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/10/2023] [Accepted: 10/04/2023] [Indexed: 10/21/2023]
Abstract
The etiology of the pregnancy syndrome preeclampsia is still unclear, while most hypotheses center on the placenta as the major contributor of the syndrome. Especially changes of the placental metabolism, including the use of glucose to produce energy, are important features. As an example, inositol phosphoglycan P-type molecules, second messengers involved in the glucose metabolism of all cells, can be retrieved from maternal urine of preeclamptic women, even before the onset of clinical symptoms. Alterations in the placental metabolism may subsequently lead to negative effects on the plasma membrane of the placental syncytiotrophoblast. This in turn may have deleterious effects on the glycocalyx of this layer and a disruption of this layer in all types of preeclampsia. The interruption of the glycocalyx in preeclampsia may result in changes of inositol phosphoglycan P-type signaling pathways and the release of these molecules as well as the release of soluble receptors such as sFlt-1 and sEndoglin. The release of placental factors later affects the maternal endothelium and disrupts the endothelial glycocalyx as well. This in turn may pave the way for edema, endothelial dysfunction, coagulation, all typical symptoms of preeclampsia.
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Affiliation(s)
- Marco Scioscia
- Department of Obstetrics and Gynecology, Mater Dei Hospital, Via SF Hahnemann 10, 70125 Bari, Italy.
| | - Monika Siwetz
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Pierre-Yves Robillard
- Centre d'Études Périnatales Océan Indien, Centre Hospitalier Universitaire Sud Réunion, Saint-Pierre, La Réunion, France; Service de Néonatologie, Centre Hospitalier Universitaire Sud Réunion, Saint-Pierre, La Réunion, France, Centre Hospitalier Universitaire Sud Réunion, Saint-Pierre, La Réunion, France
| | - Agostino Brizzi
- General and Locoregional Anesthesia Department, Santa Maria Clinic, Via A de Ferrariis, 22, 70124 Bari, Italy
| | - Berthold Huppertz
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
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4
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May RW, Maso Talou GD, Clark AR, Mynard JP, Smolich JJ, Blanco PJ, Müller LO, Gentles TL, Bloomfield FH, Safaei S. From fetus to neonate: A review of cardiovascular modeling in early life. WIREs Mech Dis 2023:e1608. [DOI: 10.1002/wsbm.1608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 01/31/2023] [Accepted: 03/03/2023] [Indexed: 04/03/2023]
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Covarrubias A, Aguilera-Olguín M, Carrasco-Wong I, Pardo F, Díaz-Astudillo P, Martín SS. Feto-placental Unit: From Development to Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1428:1-29. [PMID: 37466767 DOI: 10.1007/978-3-031-32554-0_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The placenta is an intriguing organ that allows us to survive intrauterine life. This essential organ connects both mother and fetus and plays a crucial role in maternal and fetal well-being. This chapter presents an overview of the morphological and functional aspects of human placental development. First, we describe early human placental development and the characterization of the cell types found in the human placenta. Second, the human placenta from the second trimester to the term of gestation is reviewed, focusing on the morphology and specific pathologies that affect the placenta. Finally, we focus on the placenta's primary functions, such as oxygen and nutrient transport, and their importance for placental development.
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Affiliation(s)
- Ambart Covarrubias
- Health Sciences Faculty, Universidad San Sebastián, Concepción, Chile
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Group of Research and Innovation in Vascular Health (GRIVAS Health), Chillán, Chile
| | - Macarena Aguilera-Olguín
- Biomedical Research Centre, School of Medicine, Universidad de Valparaíso, Viña del Mar, Chile
- Cellular Signalling and Differentiation Laboratory (CSDL), Medicine and Science Faculty, Universidad San Sebastián, Santiago, Chile
| | - Ivo Carrasco-Wong
- Cellular Signalling and Differentiation Laboratory (CSDL), School of Medical Technology, Medicine and Science Faculty, Universidad San Sebastián, Santiago, Chile
| | - Fabián Pardo
- Metabolic Diseases Research Laboratory, Interdisciplinary Centre of Territorial Health Research (CIISTe), Biomedical Research Center (CIB), San Felipe Campus, School of Medicine, Faculty of Medicine, Universidad de Valparaíso, San Felipe, Chile
| | - Pamela Díaz-Astudillo
- Biomedical Research Centre, School of Medicine, Universidad de Valparaíso, Viña del Mar, Chile
| | - Sebastián San Martín
- Biomedical Research Centre, School of Medicine, Universidad de Valparaíso, Viña del Mar, Chile.
- Group of Research and Innovation in Vascular Health (GRIVAS Health), Chillan, Chile.
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Zhou Q, Schirrmann K, Doman E, Chen Q, Singh N, Selvaganapathy PR, Bernabeu MO, Jensen OE, Juel A, Chernyavsky IL, Krüger T. Red blood cell dynamics in extravascular biological tissues modelled as canonical disordered porous media. Interface Focus 2022; 12:20220037. [PMID: 36325194 PMCID: PMC9560785 DOI: 10.1098/rsfs.2022.0037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/07/2022] [Indexed: 12/17/2022] Open
Abstract
The dynamics of blood flow in the smallest vessels and passages of the human body, where the cellular character of blood becomes prominent, plays a dominant role in the transport and exchange of solutes. Recent studies have revealed that the microhaemodynamics of a vascular network is underpinned by its interconnected structure, and certain structural alterations such as capillary dilation and blockage can substantially change blood flow patterns. However, for extravascular media with disordered microstructure (e.g. the porous intervillous space in the placenta), it remains unclear how the medium's structure affects the haemodynamics. Here, we simulate cellular blood flow in simple models of canonical porous media representative of extravascular biological tissue, with corroborative microfluidic experiments performed for validation purposes. For the media considered here, we observe three main effects: first, the relative apparent viscosity of blood increases with the structural disorder of the medium; second, the presence of red blood cells (RBCs) dynamically alters the flow distribution in the medium; third, symmetry breaking introduced by moderate structural disorder can promote more homogeneous distribution of RBCs. Our findings contribute to a better understanding of the cell-scale haemodynamics that mediates the relationship linking the function of certain biological tissues to their microstructure.
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Affiliation(s)
- Qi Zhou
- School of Engineering, Institute for Multiscale Thermofluids, Edinburgh, UK
| | - Kerstin Schirrmann
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - Eleanor Doman
- Department of Mathematics, The University of Manchester, Manchester, UK
| | - Qi Chen
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - Naval Singh
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - P. Ravi Selvaganapathy
- Department of Mechanical Engineering, School of Biomedical Engineering, McMaster University, Hamilton, Canada
| | - Miguel O. Bernabeu
- Centre for Medical Informatics, The University of Edinburgh, Edinburgh, UK
- The Bayes Centre, The University of Edinburgh, Edinburgh, UK
| | - Oliver E. Jensen
- Department of Mathematics, The University of Manchester, Manchester, UK
| | - Anne Juel
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - Igor L. Chernyavsky
- Department of Mathematics, The University of Manchester, Manchester, UK
- Maternal and Fetal Health Research Centre, School of Medical Sciences, The University of Manchester, Manchester, UK
| | - Timm Krüger
- School of Engineering, Institute for Multiscale Thermofluids, Edinburgh, UK
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Mekler T, Plitman Mayo R, Weissmann J, Marom G. Impact of tissue porosity and asymmetry on the oxygen uptake of the human placenta: A numerical study. Placenta 2022; 129:15-22. [PMID: 36183458 DOI: 10.1016/j.placenta.2022.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/17/2022] [Accepted: 09/14/2022] [Indexed: 12/14/2022]
Abstract
INTRODUCTION This study proposes a computational fluid dynamics model of a human placenta's independent exchange unit (placentome) to assess the effect that the inner villi distribution and decidual veins (DVs) location and number, have on the oxygen uptake. METHODS The internal placentome porosity distribution was altered in symmetric morphology, while asymmetry was introduced by varying the location and number of DVs. The DV asymmetry was introduced by either displacing them circumferentially, thereby changing the angle between them, or by adding DVs in the inlet cross-section. The results were analyzed by the changes in the normalized oxygen mass fraction and the oxygen uptake. RESULTS Oxygenated blood was shown to be delivered deeper into the placentome when the area of non-homogeneous porosity was larger. The largest oxygen uptake was achieved in the asymmetric model with the smallest angle distance between the DVs, where a 10% decrease relative to the farthest case was obtained. Placing DVs adjacent to the spiral artery opening enhanced the drainage of oxygenated blood. DISCUSSION This study demonstrates the importance of the local porosity distribution for the proper perfusion of the intervillous space and proposes a novel approach to improve our understanding of the role of the DVs in placental oxygen uptake.
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Affiliation(s)
- Tirosh Mekler
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv, 6997801, Israel.
| | - Romina Plitman Mayo
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
| | - Jonathan Weissmann
- Department of Biomedical Engineering, The Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv, 6997801, Israel.
| | - Gil Marom
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv, 6997801, Israel.
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Stathoulopoulos A, Passos A, Balabani S. Flows of healthy and hardened RBC suspensions through a micropillar array. Med Eng Phys 2022; 107:103874. [DOI: 10.1016/j.medengphy.2022.103874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/29/2022] [Accepted: 08/09/2022] [Indexed: 11/25/2022]
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Redman CW, Staff AC, Roberts JM. Syncytiotrophoblast stress in preeclampsia: the convergence point for multiple pathways. Am J Obstet Gynecol 2022; 226:S907-S927. [PMID: 33546842 DOI: 10.1016/j.ajog.2020.09.047] [Citation(s) in RCA: 130] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/14/2020] [Accepted: 09/19/2020] [Indexed: 12/29/2022]
Abstract
Preeclampsia evolves in 2 stages: a placental problem that generates signals to the mother to cause a range of responses that comprise the second stage (preeclampsia syndrome). The first stage of early-onset preeclampsia is poor placentation, which we here call malplacentation. The spiral arteries are incompletely remodeled, leading to later placental malperfusion, relatively early in the second half of pregnancy. The long duration of the first stage (several months) is unsurprisingly associated with fetal growth restriction. The first stage of late-onset preeclampsia, approximately 80% of total cases, is shorter (several weeks) and part of a process that is common to all pregnancies. Placental function declines as it outgrows uterine capacity, with increasing chorionic villous packing, compression of the intervillous space, and fetal hypoxia, and causes late-onset clinical presentations such as "unexplained" stillbirths, late-onset fetal growth restriction, or preeclampsia. The second stages of early- and late-onset preeclampsia share syncytiotrophoblast stress as the most relevant feature that causes the maternal syndrome. Syncytiotrophoblast stress signals in the maternal circulation are probably the most specific biomarkers for preeclampsia. In addition, soluble fms-like tyrosine kinase-1 (mainly produced by syncytiotrophoblast) is the best-known biomarker and is routinely used in clinical practice in many locations. How the stress signals change over time in normal pregnancies indicates that syncytiotrophoblast stress begins on average at 30 to 32 weeks' gestation and progresses to term. At term, syncytiotrophoblast shows increasing markers of stress, including apoptosis, pyroptosis, autophagy, syncytial knots, and necrosis. We label this phenotype the "twilight placenta" and argue that it accounts for the clinical problems of postmature pregnancies. Senescence as a stress response differs in multinuclear syncytiotrophoblast from that of mononuclear cells. Syncytiotrophoblast irreversibly acquires part of the senescence phenotype (cell cycle arrest) when it is formed by cell fusion. The 2 pathways converge on the common pathologic endpoint, syncytiotrophoblast stress, and contribute to preeclampsia subtypes. We highlight that the well-known heterogeneity of the preeclampsia syndrome arises from different pathways to this common endpoint, influenced by maternal genetics, epigenetics, lifestyle, and environmental factors with different fetal and maternal responses to the ensuing insults. This complexity mandates a reassessment of our approach to predicting and preventing preeclampsia, and we summarize research priorities to maximize what we can learn about these important issues.
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The etiology of preeclampsia. Am J Obstet Gynecol 2022; 226:S844-S866. [PMID: 35177222 PMCID: PMC8988238 DOI: 10.1016/j.ajog.2021.11.1356] [Citation(s) in RCA: 174] [Impact Index Per Article: 87.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/17/2021] [Accepted: 11/18/2021] [Indexed: 02/08/2023]
Abstract
Preeclampsia is one of the "great obstetrical syndromes" in which multiple and sometimes overlapping pathologic processes activate a common pathway consisting of endothelial cell activation, intravascular inflammation, and syncytiotrophoblast stress. This article reviews the potential etiologies of preeclampsia. The role of uteroplacental ischemia is well-established on the basis of a solid body of clinical and experimental evidence. A causal role for microorganisms has gained recognition through the realization that periodontal disease and maternal gut dysbiosis are linked to atherosclerosis, thus possibly to a subset of patients with preeclampsia. The recent reports indicating that SARS-CoV-2 infection might be causally linked to preeclampsia are reviewed along with the potential mechanisms involved. Particular etiologic factors, such as the breakdown of maternal-fetal immune tolerance (thought to account for the excess of preeclampsia in primipaternity and egg donation), may operate, in part, through uteroplacental ischemia, whereas other factors such as placental aging may operate largely through syncytiotrophoblast stress. This article also examines the association between gestational diabetes mellitus and maternal obesity with preeclampsia. The role of autoimmunity, fetal diseases, and endocrine disorders is discussed. A greater understanding of the etiologic factors of preeclampsia is essential to improve treatment and prevention.
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11
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Clark AR, Lee TC, James JL. Computational modeling of the interactions between the maternal and fetal circulations in human pregnancy. WIREs Mech Dis 2020; 13:e1502. [PMID: 32744412 DOI: 10.1002/wsbm.1502] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022]
Abstract
In pregnancy, fetal growth is supported by its placenta. In turn, the placenta is nourished by maternal blood, delivered from the uterus, in which the vasculature is dramatically transformed to deliver this blood an ever increasing volume throughout gestation. A healthy pregnancy is thus dependent on the development of both the placental and maternal circulations, but also the interface where these physically separate circulations come in close proximity to exchange gases and nutrients between mum and baby. As the system continually evolves during pregnancy, our understanding of normal vascular anatomy, and how this impacts placental exchange function is limited. Understanding this is key to improve our ability to understand, predict, and detect pregnancy pathologies, but presents a number of challenges, due to the inaccessibility of the pregnant uterus to invasive measurements, and limitations in the resolution of imaging modalities safe for use in pregnancy. Computational approaches provide an opportunity to gain new insights into normal and abnormal pregnancy, by connecting observed anatomical changes from high-resolution imaging to function, and providing metrics that can be observed by routine clinical ultrasound. Such advanced modeling brings with it challenges to scale detailed anatomical models to reflect organ level function. This suggests pathways for future research to provide models that provide both physiological insights into pregnancy health, but also are simple enough to guide clinical focus. We the review evolution of computational approaches to understanding the physiology and pathophysiology of pregnancy in the uterus, placenta, and beyond focusing on both opportunities and challenges. This article is categorized under: Reproductive System Diseases >Computational Models.
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Affiliation(s)
- Alys R Clark
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Tet Chuan Lee
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Joanna L James
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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12
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Dellschaft NS, Hutchinson G, Shah S, Jones NW, Bradley C, Leach L, Platt C, Bowtell R, Gowland PA. The haemodynamics of the human placenta in utero. PLoS Biol 2020; 18:e3000676. [PMID: 32463837 PMCID: PMC7255609 DOI: 10.1371/journal.pbio.3000676] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/27/2020] [Indexed: 12/12/2022] Open
Abstract
We have used magnetic resonance imaging (MRI) to provide important new insights into the function of the human placenta in utero. We have measured slow net flow and high net oxygenation in the placenta in vivo, which are consistent with efficient delivery of oxygen from mother to fetus. Our experimental evidence substantiates previous hypotheses on the effects of spiral artery remodelling in utero and also indicates rapid venous drainage from the placenta, which is important because this outflow has been largely neglected in the past. Furthermore, beyond Braxton Hicks contractions, which involve the entire uterus, we have identified a new physiological phenomenon, the ‘utero-placental pump’, by which the placenta and underlying uterine wall contract independently of the rest of the uterus, expelling maternal blood from the intervillous space. MRI provides important new insights into the function of the human placenta, revealing slow net flow and high, uniform oxygenation in healthy pregnancies, detecting changes that will lead to compromised oxygen delivery to the fetus in preeclampsia, and identifying a new physiological phenomenon, the ‘utero-placental pump’.
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Affiliation(s)
- Neele S. Dellschaft
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
- National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - George Hutchinson
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
- National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - Simon Shah
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
- National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - Nia W. Jones
- Department of Child Health, Obstetrics and Gynaecology, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Chris Bradley
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
- National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - Lopa Leach
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Craig Platt
- Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, United Kingdom
| | - Richard Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
- National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - Penny A. Gowland
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
- National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham, United Kingdom
- * E-mail:
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Erlich A, Nye GA, Brownbill P, Jensen OE, Chernyavsky IL. Quantifying the impact of tissue metabolism on solute transport in feto-placental microvascular networks. Interface Focus 2019; 9:20190021. [PMID: 31485311 PMCID: PMC6710657 DOI: 10.1098/rsfs.2019.0021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2019] [Indexed: 12/19/2022] Open
Abstract
The primary exchange units in the human placenta are terminal villi, in which fetal capillary networks are surrounded by a thin layer of villous tissue, separating fetal from maternal blood. To understand how the complex spatial structure of villi influences their function, we use an image-based theoretical model to study the effect of tissue metabolism on the transport of solutes from maternal blood into the fetal circulation. For solute that is taken up under first-order kinetics, we show that the transition between flow-limited and diffusion-limited transport depends on two new dimensionless parameters defined in terms of key geometric quantities, with strong solute uptake promoting flow-limited transport conditions. We present a simple algebraic approximation for solute uptake rate as a function of flow conditions, metabolic rate and villous geometry. For oxygen, accounting for nonlinear kinetics using physiological parameter values, our model predicts that villous metabolism does not significantly impact oxygen transfer to fetal blood, although the partitioning of fluxes between the villous tissue and the capillary network depends strongly on the flow regime.
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Affiliation(s)
- Alexander Erlich
- School of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Gareth A. Nye
- Maternal and Fetal Health Research Centre, Division of Developmental Biology and Medicine, School of Medical Sciences, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
- Chester Medical School, University of Chester, Chester CH1 4AR, UK
| | - Paul Brownbill
- Maternal and Fetal Health Research Centre, Division of Developmental Biology and Medicine, School of Medical Sciences, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
| | - Oliver E. Jensen
- School of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Igor L. Chernyavsky
- School of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Maternal and Fetal Health Research Centre, Division of Developmental Biology and Medicine, School of Medical Sciences, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK
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14
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Turk EA, Stout JN, Ha C, Luo J, Gagoski B, Yetisir F, Golland P, Wald LL, Adalsteinsson E, Robinson JN, Roberts DJ, Barth WH, Grant PE. Placental MRI: Developing Accurate Quantitative Measures of Oxygenation. Top Magn Reson Imaging 2019; 28:285-297. [PMID: 31592995 PMCID: PMC7323862 DOI: 10.1097/rmr.0000000000000221] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The Human Placenta Project has focused attention on the need for noninvasive magnetic resonance imaging (MRI)-based techniques to diagnose and monitor placental function throughout pregnancy. The hope is that the management of placenta-related pathologies would be improved if physicians had more direct, real-time measures of placental health to guide clinical decision making. As oxygen alters signal intensity on MRI and oxygen transport is a key function of the placenta, many of the MRI methods under development are focused on quantifying oxygen transport or oxygen content of the placenta. For example, measurements from blood oxygen level-dependent imaging of the placenta during maternal hyperoxia correspond to outcomes in twin pregnancies, suggesting that some aspects of placental oxygen transport can be monitored by MRI. Additional methods are being developed to accurately quantify baseline placental oxygenation by MRI relaxometry. However, direct validation of placental MRI methods is challenging and therefore animal studies and ex vivo studies of human placentas are needed. Here we provide an overview of the current state of the art of oxygen transport and quantification with MRI. We suggest that as these techniques are being developed, increased focus be placed on ensuring they are robust and reliable across individuals and standardized to enable predictive diagnostic models to be generated from the data. The field is still several years away from establishing the clinical benefit of monitoring placental function in real time with MRI, but the promise of individual personalized diagnosis and monitoring of placental disease in real time continues to motivate this effort.
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Affiliation(s)
- Esra Abaci Turk
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children’s Hospital, MA, USA
| | - Jeffrey N. Stout
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children’s Hospital, MA, USA
| | - Christopher Ha
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children’s Hospital, MA, USA
| | - Jie Luo
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Borjan Gagoski
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children’s Hospital, MA, USA
| | - Filiz Yetisir
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children’s Hospital, MA, USA
| | - Polina Golland
- Computer Science and Artificial Intelligence Laboratory (CSAIL), Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Lawrence L. Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Elfar Adalsteinsson
- Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology, Cambridge, MA, United States
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Julian N. Robinson
- Department of Obstetrics and Gynecology, Brigham and Women’s Hospital, Boston, USA
| | | | - William H. Barth
- Maternal-Fetal Medicine, Obstetrics and Gynecology, Massachusetts General Hospital, Boston, MA, USA
| | - P. Ellen Grant
- Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children’s Hospital, MA, USA
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15
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Almendros I, Martínez-Ros P, Farré N, Rubio-Zaragoza M, Torres M, Gutiérrez-Bautista ÁJ, Carrillo-Poveda JM, Sopena-Juncosa JJ, Gozal D, Gonzalez-Bulnes A, Farré R. Placental oxygen transfer reduces hypoxia-reoxygenation swings in fetal blood in a sheep model of gestational sleep apnea. J Appl Physiol (1985) 2019; 127:745-752. [PMID: 31369330 DOI: 10.1152/japplphysiol.00303.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Obstructive sleep apnea (OSA), characterized by events of hypoxia-reoxygenation, is highly prevalent in pregnancy, negatively affecting the gestation process and particularly the fetus. Whether the consequences of OSA for the fetus and offspring are mainly caused by systemic alterations in the mother or by a direct effect of intermittent hypoxia in the fetus is unknown. In fact, how apnea-induced hypoxemic swings in OSA are transmitted across the placenta remains to be investigated. The aim of this study was to test the hypothesis, based on a theoretical background on the damping effect of oxygen transfer in the placenta, that oxygen partial pressure (Po2) swings resulting from obstructive apneas mimicking OSA are mitigated in the fetal circulation. To this end, four anesthetized ewes close to term pregnancy were subjected to obstructive apneas consisting of 25-s airway obstructions. Real-time Po2 was measured in the maternal carotid artery and in the umbilical vein with fast-response fiber-optic oxygen sensors. The amplitudes of Po2 swings in the umbilical vein were considerably smaller [3.1 ± 1.0 vs. 21.0 ± 6.1 mmHg (mean ± SE); P < 0.05]. Corresponding estimated swings in fetal and maternal oxyhemoglobin saturation tracked Po2 swings. This study provides novel insights into fetal oxygenation in a model of gestational OSA and highlights the importance of further understanding the impact of sleep-disordered breathing on fetal and offspring development.NEW & NOTEWORTHY This study in an airway obstruction sheep model of gestational sleep apnea provides novel data on how swings in oxygen partial pressure (Po2) translate from maternal to fetal blood. Real-time simultaneous measurement of Po2 in maternal artery and in umbilical vein shows that placenta transfer attenuates the magnitude of oxygenation swings. These data prompt further investigation of the extent to which maternal apneas could induce similar direct oxidative stress in fetal and maternal tissues.
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Affiliation(s)
- Isaac Almendros
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain.,Institut d'Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
| | - Paula Martínez-Ros
- Animal Production and Health Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain
| | - Nuria Farré
- Department of Cardiology, Hospital del Mar, Barcelona, Spain.,Heart Diseases Biomedical Research Group, Hospital del Mar Medical Research Institute, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mónica Rubio-Zaragoza
- Bioregenerative Medicine and Applied Surgery Research Group, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain.,García Cugat Foundation for Biomedical Research, Barcelona, Spain
| | - Marta Torres
- CIBER de Enfermedades Respiratorias, Madrid, Spain.,Servei de Pneumologia, Hospital Clínic, Barcelona, Spain
| | - Álvaro J Gutiérrez-Bautista
- Anaesthesia Unit, Veterinary Teaching Hospital, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain
| | - José M Carrillo-Poveda
- Bioregenerative Medicine and Applied Surgery Research Group, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain.,García Cugat Foundation for Biomedical Research, Barcelona, Spain
| | - Joaquín J Sopena-Juncosa
- Bioregenerative Medicine and Applied Surgery Research Group, Animal Medicine and Surgery Department, Veterinary Faculty, Universidad Cardenal Herrera-CEU Universities, Valencia, Spain.,García Cugat Foundation for Biomedical Research, Barcelona, Spain
| | - David Gozal
- Department of Child Health, University of Missouri School of Medicine, Columbia, Missouri
| | - Antonio Gonzalez-Bulnes
- Department of Animal Reproduction, Deputy Directorate General of Research and Technology-Spanish National Institute for Agricultural and Food Research and Technology, Madrid, Spain
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain.,Institut d'Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
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16
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Jensen OE, Chernyavsky IL. Blood flow and transport in the human placenta. ANNUAL REVIEW OF FLUID MECHANICS 2019; 51:25-47. [PMID: 38410641 PMCID: PMC7615669 DOI: 10.1146/annurev-fluid-010518-040219] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
The placenta is a multi-functional organ that exchanges blood gases and nutrients between a mother and her developing fetus. In humans, fetal blood flows through intricate networks of vessels confined within villous trees, the branches of which are bathed in pools of maternal blood. Fluid mechanics and transport processes play a central role in understanding how these elaborate structures contribute to the function of the placenta, and how their disorganization may lead to disease. Recent advances in imaging and computation have spurred significant advances in simulations of fetal and maternal flows within the placenta, across a range of lengthscales. Models describe jets of maternal blood emerging from spiral arteries into a disordered and deformable porous medium, and solute uptake by fetal blood flowing through elaborate three-dimensional capillary networks. We survey recent developments and emerging challenges in modeling flow and transport in this complex organ.
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Affiliation(s)
| | - Igor L. Chernyavsky
- School of Mathematics, University of Manchester, UK
- Maternal and Fetal Health Research Centre, Division of Developmental
Biology & Medicine, School of Medical Sciences, Faculty of Biology, Medicine
& Health, University of Manchester, UK
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17
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Advances in Human Placental Biomechanics. Comput Struct Biotechnol J 2018; 16:298-306. [PMID: 30181841 PMCID: PMC6120428 DOI: 10.1016/j.csbj.2018.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/06/2018] [Accepted: 08/12/2018] [Indexed: 11/21/2022] Open
Abstract
Pregnancy complications are a major clinical concern due to the related maternal and fetal morbidity. Many are caused through defective placentation, but research into placental function is difficult, principally because of the ethical limitations associated with the in-vivo organ and the difficulty of extrapolating animal models. Perfused by two separate circulations, the maternal and fetal bloodstreams, the placenta has a unique structure and performs multiple complex functions. Three-dimensional imaging and computational modelling are becoming popular tools to investigate the morphology and physiology of this organ. These techniques bear the potential for better understanding the aetiology and development of placental pathologies, however, their full potential is yet to be exploited. This review aims to summarize the recent insights into placental structure and function by employing these novel techniques.
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18
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Mirbod P. Analytical model of the feto-placental vascular system: consideration of placental oxygen transport. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180219. [PMID: 29765697 PMCID: PMC5936962 DOI: 10.1098/rsos.180219] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 03/13/2018] [Indexed: 06/08/2023]
Abstract
The placenta is a transient vascular organ that enables nutrients and blood gases to be exchanged between fetal and maternal circulations. Herein, the structure and oxygen diffusion across the trophoblast membrane between the fetal and maternal red blood cells in the feto-placental vasculature system in both human and mouse placentas are presented together as a functional unit. Previous models have claimed that the most efficient fetal blood flow relies upon structures containing a number of 'conductive' symmetrical branches, offering a path of minimal resistance that maximizes blood flow to the terminal villi, where oxygen diffusion occurs. However, most of these models have disregarded the actual descriptions of the exchange at the level of the intermediate and terminal villi. We are proposing a 'mixed model' whereby both 'conductive' and 'terminal' villi are presumed to be present at the end of single (in human) or multiple (in mouse) pregnancies. We predict an optimal number of 18 and 22 bifurcation levels in the human and the mouse placentas, respectively. Wherever possible, we have compared our model's predictions with experimental results reported in the literature and found close agreement between them.
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Affiliation(s)
- Parisa Mirbod
- Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, USA
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19
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Perazzolo S, Lewis R, Sengers B. Modelling the effect of intervillous flow on solute transfer based on 3D imaging of the human placental microstructure. Placenta 2017; 60:21-27. [DOI: 10.1016/j.placenta.2017.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/29/2017] [Accepted: 10/10/2017] [Indexed: 01/05/2023]
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20
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Shah RG, Salafia CM, Girardi T, Merz GS. Villus packing density and lacunarity: Markers of placental efficiency? Placenta 2016; 48:68-71. [PMID: 27871475 DOI: 10.1016/j.placenta.2016.09.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 09/05/2016] [Accepted: 09/28/2016] [Indexed: 11/28/2022]
Abstract
We evaluate, in routine H&E histology slides, villus quantity in a given area (villous packing density, VPD) and the pattern or "gappiness" of villous distribution (lacunarity), and test for correlations with a proxy for fetoplacental metabolic rate, β calculated as (ln (placental weight)/ln (birthweight)) from Kleiber's law [1]. Three ∼4.3 mm2 images each were obtained from 88 term placentas. Ranges of VPD and lacunarity were each correlated with β (r = 0.31, p = 0.003, r = 0.23, p = 0.03 and respectively). The relationship between β and within-placenta variation in VPD and lacunarity highlights the need to study not merely the mean but the variance of villous geometries and spatial distributions.
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Affiliation(s)
- R G Shah
- Placental Analytics, LLC, New Rochelle, NY, USA
| | - C M Salafia
- Placental Analytics, LLC, New Rochelle, NY, USA; Institute for Basic Research, Staten Island, NY, USA.
| | - T Girardi
- Placental Analytics, LLC, New Rochelle, NY, USA
| | - G S Merz
- Institute for Basic Research, Staten Island, NY, USA
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21
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Pearce P, Brownbill P, Janáček J, Jirkovská M, Kubínová L, Chernyavsky IL, Jensen OE. Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries. PLoS One 2016; 11:e0165369. [PMID: 27788214 PMCID: PMC5082864 DOI: 10.1371/journal.pone.0165369] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 10/11/2016] [Indexed: 11/29/2022] Open
Abstract
During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations.
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Affiliation(s)
- Philip Pearce
- School of Mathematics, University of Manchester, Manchester, M13 9PL, United Kingdom
- * E-mail:
| | - Paul Brownbill
- Maternal and Fetal Health Research Centre, Institute of Human Development, University of Manchester, Manchester, United Kingdom
- Maternal and Fetal Health Research Centre, St. Mary’s Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, United Kingdom
| | - Jiří Janáček
- Department of Biomathematics, Institute of Physiology, v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Marie Jirkovská
- Institute of Histology and Embryology, First Faculty of Medicine, Charles University, Albertov 4, CZ-12801 Prague 2, Czech Republic
| | - Lucie Kubínová
- Department of Biomathematics, Institute of Physiology, v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Igor L. Chernyavsky
- School of Mathematics, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Oliver E. Jensen
- School of Mathematics, University of Manchester, Manchester, M13 9PL, United Kingdom
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22
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Perazzolo S, Lewis RM, Sengers BG. Modelling nutrient transfer based on 3D imaging of the human placental microstructure. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:5953-5956. [PMID: 28269608 DOI: 10.1109/embc.2016.7592084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Impaired transfer of nutrients from mother to fetus can affect pregnancy outcomes. The placenta has a complex microstructure, including the maternal intervillous space and fetal capillaries. Previous computational models of placental transfer either assumed a simplified idealized local geometry or were based on 2D imaging. In this study, we present a novel 3D computational model to assess the placental transfer of nutrients at the microscale in interaction with the maternal flow environment. A stack of confocal microscopy images of the placental terminal villi was collected and reconstructed. The 3D simulation framework was tested for the transport of oxygen. Preliminary results identified local stagnant zones, as well as areas of high nutrient transfer into the fetal capillaries in the most exposed branches of the villi as a result of better perfusion, combined with a smaller thickness of the tissue barrier. Overall, the current model may serve as a tool for assessing pregnancy conditions affected by inefficient nutrient transfer due to altered microscale placental morphology.
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23
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Lin M, Mauroy B, James JL, Tawhai MH, Clark AR. A multiscale model of placental oxygen exchange: The effect of villous tree structure on exchange efficiency. J Theor Biol 2016; 408:1-12. [PMID: 27378004 DOI: 10.1016/j.jtbi.2016.06.037] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 06/29/2016] [Accepted: 06/30/2016] [Indexed: 11/29/2022]
Abstract
The placenta is critical to fetal health during pregnancy as it supplies oxygen and nutrients to maintain life. It has a complex structure, and alterations to this structure across spatial scales are associated with several pregnancy complications, including intrauterine growth restriction (IUGR). The relationship between placental structure and its efficiency as an oxygen exchanger is not well understood in normal or pathological pregnancies. Here we present a computational framework that predicts oxygen transport in the placenta which accounts for blood and oxygen transport in the space around a placental functional unit (the villous tree). The model includes the well-defined branching structure of the largest villous tree branches, as well as a smoothed representation of the small terminal villi that comprise the placenta's gas exchange interfaces. The model demonstrates that oxygen exchange is sensitive to villous tree geometry, including the villous branch length and volume, which are seen to change in IUGR. This is because, to be an efficient exchanger, the architecture of the villous tree must provide a balance between maximising the surface area available for exchange, and the opposing condition of allowing sufficient maternal blood flow to penetrate into the space surrounding the tree. The model also predicts an optimum oxygen exchange when the branch angle is 24 °, as villous branches and TBs are spread out sufficiently to channel maternal blood flow deep into the placental tissue for oxygen exchange without being shunted directly into the DVs. Without concurrent change in the branch length and angles, the model predicts that the number of branching generations has a small influence on oxygen exchange. The modelling framework is presented in 2D for simplicity but is extendible to 3D or to incorporate the high-resolution imaging data that is currently evolving to better quantify placental structure.
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Affiliation(s)
- Mabelle Lin
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
| | - Benjamin Mauroy
- Laboratoire J. A. Dieudonné - UMR CNRS 7351, Université de Nice-Sophia Antipolis, Nice, France.
| | - Joanna L James
- Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, University of Auckland, New Zealand.
| | - Merryn H Tawhai
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
| | - Alys R Clark
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
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24
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Brownbill P, Chernyavsky I, Bottalico B, Desoye G, Hansson S, Kenna G, Knudsen LE, Markert UR, Powles-Glover N, Schneider H, Leach L. An international network (PlaNet) to evaluate a human placental testing platform for chemicals safety testing in pregnancy. Reprod Toxicol 2016; 64:191-202. [PMID: 27327413 DOI: 10.1016/j.reprotox.2016.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 05/23/2016] [Accepted: 06/07/2016] [Indexed: 12/14/2022]
Abstract
The human placenta is a critical life-support system that nourishes and protects a rapidly growing fetus; a unique organ, species specific in structure and function. We consider the pressing challenge of providing additional advice on the safety of prescription medicines and environmental exposures in pregnancy and how ex vivo and in vitro human placental models might be advanced to reproducible human placental test systems (HPTSs), refining a weight of evidence to the guidance given around compound risk assessment during pregnancy. The placental pharmacokinetics of xenobiotic transfer, dysregulated placental function in pregnancy-related pathologies and influx/efflux transporter polymorphisms are a few caveats that could be addressed by HPTSs, not the specific focus of current mammalian reproductive toxicology systems. An international consortium, "PlaNet", will bridge academia, industry and regulators to consider screen ability and standardisation issues surrounding these models, with proven reproducibility for introduction into industrial and clinical practice.
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Affiliation(s)
- Paul Brownbill
- Maternal and Fetal Health Research Centre, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK; Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
| | - Igor Chernyavsky
- School of Mathematics, University of Manchester, Manchester, UK.
| | - Barbara Bottalico
- Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Lund University, Lund, Sweden,.
| | - Gernot Desoye
- Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria.
| | - Stefan Hansson
- Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Lund University, Lund, Sweden,.
| | | | - Lisbeth E Knudsen
- Department of Public Health, Faculty Of Health Sciences, University of Copenhagen, Denmark.
| | - Udo R Markert
- Placenta-Labor Laboratory, Department of Obstetrics, Friedrich Schiller University, D-07740, Jena, Germany.
| | - Nicola Powles-Glover
- Reproductive, Development and Paediatric Centre of Excellence, AstraZeneca, Mereside, Alderley Park, Alderley Edge SK10 4TG, UK.
| | - Henning Schneider
- Department of Obstetrics and Gynecology, Inselspital, University of Bern, Switzerland.
| | - Lopa Leach
- Molecular Cell Biology & Development, School of Life Sciences, Faculty of Medicine & Health Sciences, University of Nottingham, UK.
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25
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Panitchob N, Widdows KL, Crocker IP, Johnstone ED, Please CP, Sibley CP, Glazier JD, Lewis RM, Sengers BG. Computational modelling of placental amino acid transfer as an integrated system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1451-61. [PMID: 27045077 PMCID: PMC4884669 DOI: 10.1016/j.bbamem.2016.03.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/22/2016] [Accepted: 03/31/2016] [Indexed: 01/31/2023]
Abstract
Placental amino acid transfer is essential for fetal development and its impairment is associated with poor fetal growth. Amino acid transfer is mediated by a broad array of specific plasma membrane transporters with overlapping substrate specificity. However, it is not fully understood how these different transporters work together to mediate net flux across the placenta. Therefore the aim of this study was to develop a new computational model to describe how human placental amino acid transfer functions as an integrated system. Amino acid transfer from mother to fetus requires transport across the two plasma membranes of the placental syncytiotrophoblast, each of which contains a distinct complement of transporter proteins. A compartmental modelling approach was combined with a carrier based modelling framework to represent the kinetics of the individual accumulative, exchange and facilitative classes of transporters on each plasma membrane. The model successfully captured the principal features of transplacental transfer. Modelling results clearly demonstrate how modulating transporter activity and conditions such as phenylketonuria, can increase the transfer of certain groups of amino acids, but that this comes at the cost of decreasing the transfer of others, which has implications for developing clinical treatment options in the placenta and other transporting epithelia. First computational model of placental amino acid transfer as an integrated system Increased activity of a transporter does not mean increased transfer to the fetus. Increasing transfer of certain amino acids can reduce the transfer of others. Amino acid composition as well as concentration determines transfer to the fetus. Modelling of phenylketonuria suggests inhibition by excess maternal phenylalanine.
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Affiliation(s)
- N Panitchob
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, UK
| | - K L Widdows
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - I P Crocker
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - E D Johnstone
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - C P Please
- Mathematical Institute, Oxford University, Oxford, UK
| | - C P Sibley
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - J D Glazier
- Maternal & Fetal Health Research Centre, Institute of Human Development, University of Manchester, UK; St. Mary's Hospital & Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - R M Lewis
- Faculty of Medicine, University of Southampton, UK; Institute for Life Sciences, University of Southampton, UK
| | - B G Sengers
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, UK; Institute for Life Sciences, University of Southampton, UK.
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26
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Serov AS, Salafia C, Grebenkov DS, Filoche M. The role of morphology in mathematical models of placental gas exchange. J Appl Physiol (1985) 2015; 120:17-28. [PMID: 26494446 DOI: 10.1152/japplphysiol.00543.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/08/2015] [Indexed: 02/07/2023] Open
Abstract
The performance of the placenta as a gas exchanger has a direct impact on the future health of the newborn. To provide accurate estimates of respiratory gas exchange rates, placenta models need to account for both the physiology of exchange and the organ morphology. While the former has been extensively studied, accounting for the latter is still a challenge. The geometrical complexity of placental structure requires use of carefully crafted approximations. We present here the state of the art of respiratory gas exchange placenta modeling and demonstrate the influence of the morphology description on model predictions. Advantages and shortcomings of various classes of models are discussed, and experimental techniques that may be used for model validation are summarized. Several directions for future development are suggested.
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Affiliation(s)
- A S Serov
- Physique de la Matière Condensée, Centre National de la Recherche Scientifique, Ecole Polytechnique, Palaiseau, France; and
| | - C Salafia
- Placental Analytics, LLC, Larchmont, New York
| | - D S Grebenkov
- Physique de la Matière Condensée, Centre National de la Recherche Scientifique, Ecole Polytechnique, Palaiseau, France; and
| | - M Filoche
- Physique de la Matière Condensée, Centre National de la Recherche Scientifique, Ecole Polytechnique, Palaiseau, France; and
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Serov AS, Salafia CM, Filoche M, Grebenkov DS. Analytical theory of oxygen transport in the human placenta. J Theor Biol 2015; 368:133-44. [PMID: 25580015 DOI: 10.1016/j.jtbi.2014.12.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 12/23/2014] [Indexed: 11/18/2022]
Abstract
We propose an analytical approach to solving the diffusion-convection equations governing oxygen transport in the human placenta. We show that only two geometrical characteristics of a placental cross-section, villi density and the effective villi radius, are needed to predict fetal oxygen uptake. We also identify two combinations of physiological parameters that determine oxygen uptake in a given placenta: (i) the maximal oxygen inflow of a placentone if there were no tissue blocking the flow and (ii) the ratio of transit time of maternal blood through the intervillous space to oxygen extraction time. We derive analytical formulas for fast and simple calculation of oxygen uptake and provide two diagrams of efficiency of oxygen transport in an arbitrary placental cross-section. We finally show that artificial perfusion experiments with no-hemoglobin blood tend to give a two-orders-of-magnitude underestimation of the in vivo oxygen uptake and that the optimal geometry for such setup alters significantly. The theory allows one to adjust the results of artificial placenta perfusion experiments to account for oxygen-hemoglobin dissociation. Combined with image analysis techniques, the presented model can give an easy-to-use tool for prediction of the human placenta efficiency.
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Affiliation(s)
- A S Serov
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France.
| | - C M Salafia
- Placental Analytics LLC, 93 Colonial Avenue, Larchmont, New York 10538, USA
| | - M Filoche
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France
| | - D S Grebenkov
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France
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