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Holland OJ, Hickey AJR, Alvsaker A, Moran S, Hedges C, Chamley LW, Perkins AV. Changes in mitochondrial respiration in the human placenta over gestation. Placenta 2017; 57:102-112. [PMID: 28863998 DOI: 10.1016/j.placenta.2017.06.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/24/2017] [Accepted: 06/14/2017] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Placental mitochondria are subjected to micro-environmental changes throughout gestation, in particular large variations in oxygen. How placental mitochondrial respiration adapts to changing oxygen concentrations remains unexplored. Additionally, placental tissue is often studied in culture; however, the effect of culture on placental mitochondria is unclear. MATERIAL AND METHODS Placental tissue was obtained from first trimester and term (laboured and non-laboured) pregnancies, and selectively permeabilized to access mitochondria. Respirometry was used to compare respiration states and substrate use in mitochondria. Additionally, explants of placental tissue were cultured for four, 12, 24, 48, or 96 h and respiration measured. RESULTS Mitochondrial respiration decreased at 11 weeks compared to earlier gestations (p = 0.05-0.001), and mitochondrial content increased at 12-13 weeks compared to 7-10 weeks (p = 0.042). In term placentae, oxidative phosphorylation (OXPHOS) through mitochondrial complex IV (p < 0.001), the relative proportion of OXPHOS CI (p < 0.001), the total capacity of the respiratory system (p = 0.003), and mitochondrial content (p < 0.001) were higher compared to first trimester. Respiration was increased (p ≤ 0.006-0.001) in laboured compared to non-laboured placenta. After four hours of culture, respiration was depressed compared to fresh tissue from the same placenta and continued to decline with time in culture. Markers of apoptosis were increased, while markers of autophagy, mitochondrial biogenesis, and mitochondrial membrane potential were decreased after four hours of culture. DISCUSSION Respiration and mitochondrial content alter over gestation/with labour. Decreased respiration at 11 weeks and increased mitochondrial content at 12-13 weeks may relate to onset of maternal blood flow, and increased respiration as a result of labour may be an adaptation to ischaemia-reperfusion. At term, mitochondria were more susceptible to changes in respiratory function relative to first trimester when cultured in vitro, perhaps reflecting changes in metabolic demands as gestation progresses. Metabolic plasticity of placental mitochondria has relevance to placenta-mediated diseases.
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Affiliation(s)
- Olivia J Holland
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport, Queensland, Australia.
| | - Anthony J R Hickey
- School of Biological Sciences, Faculty of Sciences, The University of Auckland, New Zealand
| | - Anna Alvsaker
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport, Queensland, Australia
| | - Stephanie Moran
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport, Queensland, Australia
| | - Christopher Hedges
- School of Biological Sciences, Faculty of Sciences, The University of Auckland, New Zealand
| | - Lawrence W Chamley
- Department of Obstetrics and Gynaecology, The University of Auckland, New Zealand
| | - Anthony V Perkins
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Southport, Queensland, Australia
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Malek A, Sager R, Altermatt HJ, Gaeng D, Leiser R, Schneider H. Glucose Consumption and Lactate Production of Human Placental Tissue Under Different Conditions of In Vitro Incubation. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/107155769600300303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | | | | | | | | | - Henning Schneider
- Departments of Obstettrics and Gynecology and Pathology, University of Berne, Berne, Switzerland; Department of Veterinary Anatomy, University of Giessen, Giessen, Germany
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Samson J, Mari G, Dick E, Hubbard G, Ferry R, Schlabritz-Loutsevitch N. The morphometry of materno-fetal oxygen exchange barrier in a baboon model of obesity. Placenta 2011; 32:845-51. [PMID: 21872927 PMCID: PMC3304583 DOI: 10.1016/j.placenta.2011.07.083] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 07/21/2011] [Accepted: 07/22/2011] [Indexed: 12/21/2022]
Abstract
INTRODUCTION More than one-fourth of U.S. women are overweight; more than one-third are obese. Maternal obesity has been linked to an increased incidence of stillbirths, fetal macrosomia, fetal intrauterine growth restriction and pre-eclampsia. The placenta plays a key role in the nutrients and oxygen supply to the fetus. The data about structural changes in the placental villous membrane (VM), a major component of the feto-maternal nutrient and oxygen exchange barrier, during obesity are sparse and inconsistent. Our objective was to evaluate the morphometric changes in the placental exchange barrier in a baboon model of obesity. MATERIALS AND METHODS The previously described baboon model of maternal obesity was studied. We compared 4 obese to 4 non-obese baboons. Placental stereology with the use of transmission electron microscopy was performed to estimate VM oxygen diffusing capacities and morphometry. RESULTS The specific placental oxygen diffusing capacities per unit of fetal weight were similar in baboons and humans. Maternal leptin concentrations correlated negatively with placental basement membrane thickness (r = -0.78, p < 0.05), while fetal leptin levels correlated negatively with endothelial thickness of fetal capillaries (r = -0.78, p < 0.05). The total and specific villous membrane oxygen diffusing capacities were not different between the two groups. CONCLUSION To the best of our knowledge this is the first report of placental oxygen diffusing capacities and placental ultrastructural changes in a baboon model of obesity. Previously reported placental inflammation in maternal obesity is not associated with changes in the VM diffusing capacities and ultrastructure.
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Affiliation(s)
- J.E. Samson
- Department of Obstetrics and Gynecology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - G. Mari
- Department of Obstetrics and Gynecology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - E.J. Dick
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - G.B. Hubbard
- Department of Pathology, University of Texas Health Science Center, San Antonio, TX, USA
| | - R.J. Ferry
- Division of Pediatric Endocrinology and Metabolism, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA
- Division of Pediatric Endocrinology, Department of Pediatrics, Le Bonheur Children's Hospital, Memphis, TN, USA
- St. Jude Children's Research Hospital, Memphis, TN, USA
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Tissot van Patot M, Valdez M, Becky V, Cindrova-Davies T, Johns J, Zwerdling L, Jauniaux E, Burton G. Impact of Pregnancy at High Altitude on Placental Morphology in Non-native Women With and Without Preeclampsia. Placenta 2009; 30:523-8. [DOI: 10.1016/j.placenta.2009.04.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 03/31/2009] [Accepted: 04/02/2009] [Indexed: 11/29/2022]
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Babischkin JS, Burleigh DW, Mayhew TM, Pepe GJ, Albrecht ED. Developmental regulation of morphological differentiation of placental villous trophoblast in the baboon. Placenta 2001; 22:276-83. [PMID: 11286563 DOI: 10.1053/plac.2000.0621] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The present study determined whether morphological differentiation of placental villous cytotrophoblasts into syncytiotrophoblast during primate pregnancy was developmentally regulated and whether oestrogen has a role in this process. Placental volumetric composition of the cytotrophoblast and syncytiotrophoblast was determined by the test-point counting method on days 45-54, 60, 100, and 170 of gestation (term=184 days) in untreated baboons, on day 60 after placental oestrogen production was prematurely elevated by administration of aromatizable androstenedione or oestradiol, and on day 170 after oestrogen production was suppressed by administration of aromatase inhibitor CGS 20267. Cytotrophoblast and syncytiotrophoblast volumes and oestrogen levels increased (P< 0.01) with advancing gestation. Due to the rise in syncytiotrophoblast volume (12-fold) exceeded that of the cytotrophoblast (threefold), the mean (sem) ratio of syncytiotrophoblast and cytotrophoblast volumes increased (P< 0.001) from 3.4 (0.5) ml on day 60 to 12.1 (2.8) ml on day 170. Androstenedione administration elevated serum oestradiol levels threefold (P< 0.01) and increased the ratio of syncytiotrophoblast: cytotrophoblast volumes on day 60 by 50 per cent (P< 0.03) to that normally observed on day 100. However, the ratio of trophoblast volumes was unaltered in oestradiol-treated and CGS 20267-treated baboons. It is concluded that there is a developmental increase in morphological differentiation of the placental villous trophoblast during primate pregnancy and that androstenedione potentially via its conversion to oestrogen has a role in this process.
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Affiliation(s)
- J S Babischkin
- Department of Obstetrics, Center for Studies in Reproduction, The University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Hoggard N, Crabtree J, Allstaff S, Abramovich DR, Haggarty P. Leptin secretion to both the maternal and fetal circulation in the ex vivo perfused human term placenta. Placenta 2001; 22:347-52. [PMID: 11286571 DOI: 10.1053/plac.2001.0628] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The contribution of placental leptin, if any, to both the fetal and maternal circulation and its role in pregnancy remains to be determined. In an experiment to investigate this, 27 placentae from term pregnancies were perfused ex vivo (gestational age=39.5 s.d. 1.2; range=38-42 weeks: fetal weight=3285 s.d. 482; range=2480-4420; birthweight centile range=4th to the 98th) at both the maternal and fetal interface. Placental leptin was exported into both the maternal and fetal circulations. The log leptin production by the maternal side of the placenta was significantly greater (P=0.001) than that for the fetal side (5.193 s.d.1.049 versus 4.387 s.d. 0.768 ng/placenta/min). There was no significant relationship between maternal and fetal log leptin production and maternal body mass index, birthweight, birthweight centile, ponderal index or gestational age or with cord blood pO(2), pCO(2) and pH. There was however, a significant increase in the maternal log leptin production with increasing fetal to placental weight ratio (P=0.017; r(2)=20.7 per cent) but no corresponding relationship for fetal leptin production. It is proposed that such a mechanism would allow the placenta to modulate fat supply to the fetus in response to the fetal demand relative to placental supply.
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Affiliation(s)
- N Hoggard
- ACERO, Department of Molecular Physiology, Rowett Research Institute, Aberdeen, Scotland, UK.
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Abstract
The human placenta in vivo consumes large amounts of oxygen. After delivery the placenta is exposed to anoxia and under in vitro experimental conditions oxygen consumption is only a fraction of in vivo estimates. In spite of a reduced oxygen supply, structural and functional integrity of the tissue is surprisingly well preserved. Special metabolic adjustments in the sense of 'partial metabolic arrest' may be the explanation for a remarkable survival capacity of placental tissue and reduction of protein synthesis seems to be an important component of metabolic slowdown. The potential significance of this special feature of placental metabolism for the in vivo situation is discussed.
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Affiliation(s)
- H Schneider
- Department of Obstetrics and Gynecology, Inselspital-Universität Bern, Switzerland
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Kosanke G, Kadyrov M, Korr H, Kaufmann P. Maternal anemia results in increased proliferation in human placental villi. Placenta 1998. [DOI: 10.1016/s0143-4004(98)80024-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
The increasing practice of preterm delivery in the fetal interest for conditions such as pre-eclampsia or intrauterine growth restriction (IUGR) has provided an opportunity to study placental structure in pregnancies with prenatal evidence of fetal compromise. These data suggest that the origin of fetal hypoxia in IUGR with absent end-diastolic flow in the umbilical arteries is due to a failure of oxygen transport from intervillous space to umbilical vein. Failure of the fetoplacental circulation to extract oxygen from the intervillous space under such circumstances means intervillous PO2 is closer to maternal arterial values than under physiological conditions. Correspondingly the placental villi are chronically exposed to a higher oxygen tension than under normal circumstances--the term ¿hyperoxia', relative to normal intraplacental oxygenation, is proposed to describe this situation. Both the trophoblast and villous core react to increased oxygen despite fetal hypoxia. These results challenge the generally accepted concept of ¿placental hypoxia' in all circumstances where fetal hypoxia might arise. Therefore three categories are proposed for the origins of fetal hypoxia: (1) preplacental hypoxia; (2) uteroplacental hypoxia; and (3) postplacental hypoxia. Examples for these three disease states are listed in this review and the structural reaction patterns of placental villi to these differences in oxygenation are discussed.
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Affiliation(s)
- J C Kingdom
- Department of Obstetrics and Gynaecology, University College London Medical School, UK
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Abstract
The new stereology permits the objective, quantitative description of morphology by efficient and design-based methods. Applications to placentas in normal and abnormal pregnancies have proved of great value for challenging earlier misconceptions and interpreting better the processes of growth, morphogenesis, adaptation, and functioning at the whole-organ level. This contribution reviews the essential features of the stereological approach, identifies useful structural quantities, and provides examples of their application in various experiments of nature. We focus particularly on normal gestation and the effects of pregnancies associated with high altitude, maternal diabetes mellitus, preeclampsia, and maternal smoking.
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Affiliation(s)
- T M Mayhew
- Department of Human Anatomy & Cell Biology, Queen's Medical Centre, University of Nottingham, United Kingdom
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11
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Abstract
Paraffin-embedded histological material was examined from 10 placentae from uncomplicated pregnancies at high altitude (3000 m). This was compared with material from 10 placentae delivered at low altitude (500 m). The sample groups were matched for maternal age, gestational age and parity. Within terminal and intermediate villi the volume-weighted mean cytotrophoblast cell volume did not significantly change at high altitude (754.1 microm3 at low altitude versus 796 microm3 at high altitude). The fractional volume of the villi occupied by cytotrophoblastic cells and their nuclei number per 10000 microm3 of villous tissue were significantly greater in placenta from high altitude (3.17 and 1.86 per cent, respectively) than those from low altitude (1.05 and 0.79 per cent, respectively) (P<0.0004 and P<0.0058, respectively). No significant differences in either fractional volume of the syncytiotrophoblast or its nuclei number per 10000 microm3 of villous tissue were observed between placentae from high (26.01 and 11.6 per cent, respectively) and low altitude (26.33 and 11.89 per cent, respectively). These results suggest an increase in the number of cytotrophoblastic cells at high altitudes without any changes in their volume. Exposure to hypobaric hypoxia is thought to be the principal aetiological factor.
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Affiliation(s)
- K Z Ali
- Anatomy Department, College of Medicine, King Saud University, Abha Branch, Saudi Arabia
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Kanayama N, Tsujimura R, She L, Maehara K, Terao T. Cold-induced stress stimulates the sympathetic nervous system, causing hypertension and proteinuria in rats. J Hypertens 1997; 15:383-9. [PMID: 9211173 DOI: 10.1097/00004872-199715040-00009] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To determine whether cold-stress stimulation of the soles of the paws would produce a preeclampsia-like syndrome in rats. METHODS Pregnant or nonpregnant rats were kept in 0 degree C floor and 23 degrees C room temperature cages (the cold-stressed group) or in 23 degrees C floor and 23 degrees C room temperature cages (the control group) for 2 weeks. Their blood pressure, proteinuria, and plasma catecholamines were measured, and histologic studies were performed on all groups. RESULTS There were no significant differences in systolic blood pressure between the two groups during the first week of the experimental period; however, during the last week of gestation the blood pressure of the cold-stressed group did not fall and was significantly higher than that of the control group. A significant increase in urinary protein excretion was observed in the cold-stimulated pregnant rats, in contrast to the control rats. The concentrations of norepinephrine and epinephrine in the cold-stressed pregnant rats were markedly higher than those in the control rats. A decrease in trophoblast invasion, congestion, and fibrinoid deposits of the labyrinth were observed in the cold-stressed rats. A marked increase in subendothelial fibrinoid deposits in the glomerular capillary was found only in the cold-stressed pregnant rats. The blood pressure, biochemical parameters, and histologic findings in the nonpregnant rats were almost the same as those in the pregnant rats. CONCLUSION Chronic local cold stimulation of the soles of the paws induces preeclampsia-like phenomena in pregnant and nonpregnant rats, and this model suggests that the cause of preeclampsia is involved in chronic stimulation of the sympathetic nerve.
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Affiliation(s)
- N Kanayama
- Department of Obstetrics and Gynecology, Hamamatsu University School of Medicine, Japan
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Genbacev O, Joslin R, Damsky CH, Polliotti BM, Fisher SJ. Hypoxia alters early gestation human cytotrophoblast differentiation/invasion in vitro and models the placental defects that occur in preeclampsia. J Clin Invest 1996; 97:540-50. [PMID: 8567979 PMCID: PMC507049 DOI: 10.1172/jci118447] [Citation(s) in RCA: 404] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
During normal human pregnancy a subpopulation of fetal cytotrophoblast stem cells differentiate and invade the uterus and its arterioles. In the pregnancy disease preeclampsia, cytotrophoblast differentiation is abnormal and invasion is shallow. Thus, the placenta is relatively hypoxic. We investigated whether lowering oxygen tension affects cytotrophoblast differentiation and invasion. Previously we showed that when early gestation cytotrophoblast stem cells are cultured under standard conditions (20% O2) they differentiate/invade, replicating many aspects of the in vivo process. Specifically, the cells proliferate at a low rate and rapidly invade extracellular matrix (ECM) substrates, a phenomenon that requires switching their repertoire of integrin cell-ECM receptors, which are stage-specific antigens that mark specific transitions in the differentiation process. In this study we found that lowering oxygen tension to 2% did not change many of the cells' basic processes. However, there was a marked increase in their incorporation of [3H]thymidine and 5-bromo-2'-deoxyuridine (BrdU). Moreover, they failed to invade ECM substrates, due at least in part to their inability to completely switch their integrin repertoire. These changes mimic many of the alterations in cytotrophoblast differentiation/invasion that occur in preeclampsia, suggesting that oxygen tension plays an important role in regulating these processes in vivo.
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Affiliation(s)
- O Genbacev
- Department of Stomatology, University of California San Francisco 94143-0512, USA
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Mayhew TM, Simpson RA. Quantitative evidence for the spatial dispersal of trophoblast nuclei in human placental villi during gestation. Placenta 1994; 15:837-44. [PMID: 7886024 DOI: 10.1016/s0143-4004(05)80185-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A common assertion in the literature is that Langhans cells in placental villi decline in number during gestation but this is a misinterpretation which may be caused by the greater growth of villous surface area compared with trophoblast volume. To test this possibility, human placentae were collected at 12-41 weeks of gestation for a cross-sectional study on the packing density of nuclei within villous trophoblast. Numbers of nuclei in the cyto- and syncytiotrophoblast were estimated using a design-based stereological device, the physical disector (parallel pairs of sections). Surface areas were estimated in order to assess the overall growth of villous arborizations. Packing densities of nuclei were calculated and expressed as numbers/1000 microns 2 of villous surface. Densities decreased during gestation and this can be explained by expansion of villous surface area and thinning of trophoblast. The biggest drop in packing density of cytotrophoblast nuclei (30 per cent) occurred between 17-21 and 22-26 weeks and this period coincided with the largest changes in villous surface area (62 per cent increase) and trophoblast thickness (30 per cent decrease). Results are consistent with the notion of an epithelial proliferative unit of constant volume and comprising about nine syncytiotrophoblast nuclei per Langhans cell.
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Affiliation(s)
- T M Mayhew
- Department of Human Morphology, University of Nottingham, Queen's Medical Centre, UK
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Karimu AL, Burton GJ. Compliance of the human placental villus membrane at term: The concept of the fetoplacental unit as an autoregulating gas exchange system. Placenta 1994. [DOI: 10.1016/s0143-4004(05)80372-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Karimu AL, Burton GJ. The effects of maternal vascular pressure on the dimensions of the placental capillaries. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1994; 101:57-63. [PMID: 8297870 DOI: 10.1111/j.1471-0528.1994.tb13011.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The study sought stereological evidence for the sluice flow phenomenon in the human term placenta. DESIGN Two series of experiments were conducted on caesarean delivered placentae. In both, two fetal arteries were cannulated and perfused. In the first series, five placentae were perfusion-fixed under arterial pressures of 40 mmHg and 60 mmHg, and an external pressure of 10 mmHg in the intervillous space. In the second series, five placentae were perfusion-fixed at arterial pressures of 70 mmHg and 90 mmHg with an external pressure of 30 mmHg. Stereological estimates relating to the size of the capillaries and the thickness of the villous membrane were then made. RESULTS In each series, as the arterial pressure rose, there was an increase in the volume fraction and surface area of the fetal capillaries, and a concomitant decrease in the mean thickness of the villous membrane. These changes were negated as the external pressure rose, indicating the importance of the pressure differential between the capillary lumen and the intervillous space in determining the dimensions of the fetal capillaries. CONCLUSIONS The study demonstrated that placental capillaries are elastic and hence deformable. If a sufficiently high pressure is generated in the intervillous space, they may therefore be compressed. This may explain the increase in umbilical vascular resistance demonstrated by doppler studies in pregnant women scanned in the supine position. In this situation the venous drainage from the intervillous space is believed to be impeded by the gravid uterus compressing the inferior vena cava.
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Affiliation(s)
- A L Karimu
- Department of Anatomy, University of Cambridge, UK
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Zhou Y, Chiu K, Brescia RJ, Combs CA, Katz MA, Kitzmiller JL, Heilbron DC, Fisher SJ. Increased depth of trophoblast invasion after chronic constriction of the lower aorta in rhesus monkeys. Am J Obstet Gynecol 1993; 169:224-9. [PMID: 8333462 DOI: 10.1016/0002-9378(93)90172-f] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Our purpose was to investigate whether a reduction in uteroplacental perfusion pressure would produce changes in trophoblast-uterine interactions at the cellular level. STUDY DESIGN Strictures were placed around the abdominal aortas of rhesus monkeys at 116 +/- 7 days of pregnancy to reduce uteroplacental perfusion pressure. Placental bed biopsy specimens were obtained at cesarean section, and cytotrophoblasts were identified by means of an anticytokeratin antibody. RESULTS In monkeys without aortic strictures, interstitial trophoblast invasion was restricted to the outer half of the endometrium. Endovascular trophoblast invasion involved the entire endometrial portion of uterine vessels and extended through the subjacent half of their myometrial segments. In seven of nine monkeys with aortic strictures the depth of interstitial trophoblast invasion was substantially increased and extended throughout the entire decidua and at least a portion of the myometrium. In contrast, the pattern of endovascular trophoblast invasion was identical to that observed in the placental beds of control animals. CONCLUSION These results suggest that uteroplacental perfusion pressure or oxygen content may be important physiologic factors controlling the depth of interstitial cytotrophoblast invasion.
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Affiliation(s)
- Y Zhou
- Department of Stomatology, University of California, San Francisco 94143-0512
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Kay HH, Hawkins SR, Wang Y, Mika DE, Ribeiro AA, Spicer LD. Phosphorus 31 magnetic resonance spectroscopy of perifused human placental villi under varying oxygen concentrations. Am J Obstet Gynecol 1993; 168:246-52. [PMID: 8420335 DOI: 10.1016/s0002-9378(12)90921-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Initial phosphorus magnetic resonance spectroscopy observations on the oxygen metabolism of placental villi from normal term pregnancies are described. STUDY DESIGN Villi were suspended in medium and perifused within a custom-designed 30 mm nuclear magnetic resonance probe in a superconducting vertical nuclear magnetic resonance magnet where pH, temperature, and oxygenation were monitored. RESULTS Phosphorus resonances were observed from adenosine triphosphate, phosphomonoesters. inorganic phosphate, and phosphodiesters. No phosphocreatine signal was observed. The placental villus tissue responded to an increase in oxygen concentration of the perifusate with a rise in the adenosine triphosphate level and a concomitant decline in the inorganic phosphate and the phosphomonoester signals. CONCLUSION The changes observed reflect continuing dynamic glycolysis and oxidative phosphorylation. The absence of a phosphocreatine peak suggests that aerobic pathways not driven by creatine kinase are important for placental metabolism. Our system demonstrates dynamic oxygen metabolism in perifused viable placental villus tissue by means of magnetic resonance spectroscopy.
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Affiliation(s)
- H H Kay
- Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC 27710
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Jackson MR, Mayhew TM, Boyd PA. Quantitative description of the elaboration and maturation of villi from 10 weeks of gestation to term. Placenta 1992; 13:357-70. [PMID: 1438084 DOI: 10.1016/0143-4004(92)90060-7] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Stereological methods have been applied to a cross-sectional sample of human placentae collected at 10-41 weeks of gestation in order to provide a quantitative description of the growth and maturation of villi. Random tissue sections were analysed to derive volumes, surface areas, lengths, diameters and membrane thicknesses for villi and their fetal capillaries. Expansion of the total volume and surface area of villi can be explained by a dramatic linear growth of terminal villi which begins at about the middle of the second trimester. Growth of intermediate villi also occurs but to a more limited extent. Linear growth is accompanied by villous maturation which involves increases in the relative volume of capillaries and in villous capillarization coupled with decreases in villous diameter, capillary diameter and harmonic thickness of the villous membrane. These findings confirm that placental growth and development depend greatly on growth and maturation of terminal villi. They do not confirm sinusoidal dilation of fetal vessels as a generalized phenomenon. They also support the contention that changes in effective diffusion distances across the villous membrane have real adaptive significance.
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Affiliation(s)
- M R Jackson
- Department of Human Anatomy, University of Oxford, UK
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Burton GJ, Palmer ME. Development of the chick chorioallantoic capillary plexus under normoxic and normobaric hypoxic and hyperoxic conditions: a morphometric study. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1992; 262:291-8. [PMID: 1640200 DOI: 10.1002/jez.1402620309] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Fertile eggs from the domestic fowl were incubated under normobaric normoxic (21% O2), hypoxic (14% O2), and hyperoxic (40% O2) conditions in order to examine the influence of the prevailing oxygen level on the growth and maturation of the chorioallantoic membrane. Eggs were sampled at regular stages throughout incubation for morphometric analysis. Under normoxic conditions, maturation of the capillary plexus occurred in two distinct stages, both of which contributed to a reduction in the thickness of the air-blood barrier. Between days 6 and 10, the capillaries sprouted and fused to form a dense plexus. Subsequently, between days 10 and 14, this plexus invaginated into the chorionic epithelium. Differentiation of the chorioallantoic membrane appeared maximal by the end of this period. Hypoxia resulted in diminished growth of the embryo and chorioallantoic membrane, but in accelerated maturation of the capillary plexus. Hyperoxia had a less marked effect but appeared to retard the final invagination of the plexus, resulting in a thicker air-blood barrier.
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Affiliation(s)
- G J Burton
- Department of Anatomy, Cambridge, United Kingdom
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21
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Ong PJ, Burton GJ. Thinning of the placental villous membrane during maintenance in hypoxic organ culture: structural adaptation or syncytial degeneration? Eur J Obstet Gynecol Reprod Biol 1991; 39:103-10. [PMID: 2050250 DOI: 10.1016/0028-2243(91)90072-s] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This study was undertaken in order to reinvestigate claims that the human placenta is able to adapt structurally under hypoxic stress so as to facilitate materno-fetal oxygen exchange. The results confirmed that thinning of the villous membrane does occur after maintenance for 10 h in an atmosphere of 6% oxygen, and that this effect is partially reversed by maintenance for a further 10 h under normoxic conditions (21% O2). However, throughout these experiments the values for both the arithmetic and the harmonic mean thicknesses of the villous membrane altered in an identical fashion. This indicates that the thinning observed was not the result of redistribution of the syncytiotrophoblast around the villous surface, with movement away from the sites of the fetal capillaries as previously postulated. Rather, it must have been caused by a reduction in the total mass of the syncytium, resulting from either involution and partial degeneration of its organelles, or some form of fluid-shift phenomenon. Whatever the cause, these effects were only partially reversed after further culture for 10 h in well-oxygenated conditions. Thus whilst there is an accumulating body of evidence to suggest that the placenta can adapt structurally to hypoxia in vivo, it is apparent that the in vitro organ culture system is not a suitable model with which to investigate the process.
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Affiliation(s)
- P J Ong
- Department of Anatomy, University of Cambridge, U.K
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22
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Feneley MR, Burton GJ. Villous composition and membrane thickness in the human placenta at term: a stereological study using unbiased estimators and optimal fixation techniques. Placenta 1991; 12:131-42. [PMID: 1871071 DOI: 10.1016/0143-4004(91)90017-a] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The aim of this study was to obtain unbiased estimates of in vivo villous composition and membrane thickness in the human placenta at term. By taking biopsies of the placenta 1 min after separation during caesarean section, and at regular intervals thereafter, it was possible to extrapolate back to the time zero values. It was estimated that at term intermediate and terminal villi are composed of 25.3 per cent trophoblast, 36.2 per cent stromal core and 37.1 per cent fetal capillaries. The villous membrane, defined as the outer surface of the syncytiotrophoblast (excluding the microvilli) to the inner surface of the capillary endothelium, was estimated to have an arithmetic mean thickness of 4.53 microns and a harmonic mean thickness of 3.65 microns. Villous composition and membrane thickness were found to change rapidly after delivery, despite the umbilical cord remaining clamped, and these changes were believed to be predominantly due to leakage of fetal blood or plasma from sites of damage to the villous tree caused at the time of delivery. These estimates do not, and indeed cannot, take into account the fact that the villi sampled have been removed from their uterine environment, and thus from the influences of the maternal and fetal blood pressures. However, they are free from methodological errors that have detracted from previous studies, and thus allow the morphometric diffusing capacity of the placenta at term to be calculated more accurately. They also provide baseline data against which measurements obtained from pathological pregnancies can be compared.
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Affiliation(s)
- M R Feneley
- Department of Anatomy, University of Cambridge, UK
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Mayhew TM, Jackson MR, Haas JD. Oxygen diffusive conductances of human placentae from term pregnancies at low and high altitudes. Placenta 1990; 11:493-503. [PMID: 2290801 DOI: 10.1016/s0143-4004(05)80195-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A morphometric model of oxygen diffusion is employed to calculate the partial, total and specific conductances of human placentae from low- and high-altitude term pregnancies. Placentae were obtained from indigenous and non-indigenous populations and the diffusion pathway dissected into six tissue compartments. Birthweights were reduced at high altitude but were greater in natives versus non-natives. The altitudinal differences were associated with changes in placental diffusive conductances. The partial conductance of the villous trophoblast was conserved but the conductance on the maternal side was increased as was the conductance of the villous stroma. Fetal conductances were conserved (plasma) or diminished (erythrocytes). We conclude that birthweights are reduced at high altitude despite the attempts to increase the total placental diffusive conductance for oxygen. The mechanisms underlying these adaptations are discussed.
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Affiliation(s)
- T M Mayhew
- School of Biomedical Sciences, Division of Anatomy, Marischal College, University of Aberdeen, UK
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