Amniotic gas values and acid-base status during acute maternal hyperoxemia and hypoxemia in the early fetal sheep

Jauniaux, Eric; Kiserud, Torvid; Ozturk, Ozkan; West, Daniel; Hanson, Mark A.

doi:10.1067/mob.2000.103937

Cited by 9 publications

(6 citation statements)

References 28 publications

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“…Maternal blood volume, cardiac output, and heart rate are increased early in pregnancy, but blood pressure is normally decreased, starting in the second trimester, as a result of decreased resistance in the peripheral vasculature [18]. Placental oxygen tension is low in the beginning of pregnancy [19], but PO 2 increases around weeks 10–12 of pregnancy as intervillous blood flow increases and supplies the placenta with oxygen and nutrient delivery [20, 21]. …”

Section: Preeclampsia Is Associated With Placental Ischemiamentioning

confidence: 99%

Placental Ischemia and Resultant Phenotype in Animal Models of Preeclampsia

et al. 2016

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Preeclampsia is new onset (or worsening of preexisting) hypertension that occurs during pregnancy. It is accompanied by chronic inflammation, intrauterine growth restriction, elevated anti-angiogenic factors, and can occur with or without proteinuria. Although the exact etiology is unknown, it is thought that preeclampsia begins early in gestation with reduced uterine spiral artery remodeling leading to decreased vasculogenesis of the placenta as the pregnancy progresses. Soluble factors, stimulated by the ischemic placenta, shower the maternal vascular endothelium and are thought to cause endothelial dysfunction and to contribute to the development of hypertension during pregnancy. Due to the difficulty in studying such soluble factors in pregnant women, various animal models have been designed. Studies from these models have contributed to a better understanding of how factors released in response to placental ischemia may lead to increased blood pressure and reduced fetal weight during pregnancy. This review will highlight various animal models and the major findings indicating the importance of placental ischemia to lead to the pathophysiology observed in preeclamptic patients.

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Section: Preeclampsia Is Associated With Placental Ischemiamentioning

confidence: 99%

Placental Ischemia and Resultant Phenotype in Animal Models of Preeclampsia

et al. 2016

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“…During the pre-implantation period, the oxygen tensions were about 60 mmHg in oviducts of rabbits (Mastroianni and Jones, 1965), but less than 10 mmHg in uterus of rhesus monkeys (Maas et al, 1976), 5–50 and 25–50 mmHg in uterus of the hamsters and rats (Kaufman and Mitchell, 1990). After the implantation of embryos the oxygen tension in amniotic fluid was 10.9 ± 1.0 mmHg in the early gestation and 11.6 ± 0.7 mmHg in mid gestation of sheep (Jauniaux et al, 2000). During the late gestation, although the onset of placental gas exchange establishes, the P O2 values for umbilical artery, vein, and amniotic fluid are still constrained below maternal venous levels (23, 30, and 12 mmHg, respectively; Eskes et al, 1983; Yeomans et al, 1985; Rurak et al, 1987; Jauniaux et al, 2000).…”

Section: Oxygen Niche During Embryonic and Adult Neurogenesismentioning

confidence: 99%

“…After the implantation of embryos the oxygen tension in amniotic fluid was 10.9 ± 1.0 mmHg in the early gestation and 11.6 ± 0.7 mmHg in mid gestation of sheep (Jauniaux et al, 2000). During the late gestation, although the onset of placental gas exchange establishes, the P O2 values for umbilical artery, vein, and amniotic fluid are still constrained below maternal venous levels (23, 30, and 12 mmHg, respectively; Eskes et al, 1983; Yeomans et al, 1985; Rurak et al, 1987; Jauniaux et al, 2000). In summary, the whole process of embryonic development is under the low-oxygen concentration.…”

Section: Oxygen Niche During Embryonic and Adult Neurogenesismentioning

confidence: 99%

Oxygen, a Key Factor Regulating Cell Behavior during Neurogenesis and Cerebral Diseases

Zhang¹,

Zhu²,

Fan³

2011

Front. Mol. Neurosci.

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Oxygen is vital to maintain the normal functions of almost all the organs, especially for brain which is one of the heaviest oxygen consumers in the body. The important roles of oxygen on the brain are not only reflected in the development, but also showed in the pathological processes of many cerebral diseases. In the current review, we summarized the oxygen levels in brain tissues tested by real-time measurements during the embryonic and adult neurogenesis, the cerebral diseases, or in the hyperbaric/hypobaric oxygen environment. Oxygen concentration is low in fetal brain (0.076–7.6 mmHg) and in adult brain (11.4–53.2 mmHg), decreased during stroke, and increased in hyperbaric oxygen environment. In addition, we reviewed the effects of oxygen tensions on the behaviors of neural stem cells (NSCs) in vitro cultures at different oxygen concentration (15.2–152 mmHg) and in vivo niche during different pathological states and in hyperbaric/hypobaric oxygen environment. Moderate hypoxia (22.8–76 mmHg) can promote the proliferation of NSCs and enhance the differentiation of NSCs into the TH-positive neurons. Next, we briefly presented the oxygen-sensitive molecular mechanisms regulating NSCs proliferation and differentiation recently found including the Notch, Bone morphogenetic protein and Wnt pathways. Finally, the future perspectives about the roles of oxygen on brain and NSCs were given.

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“…During pregnancy and parturition, oxygen levels and its transport have to be constantly adjusted. At the time of implantation and early pregnancy, the oxygen level in the uterus is low (Jauniaux et al 2000). This early pregnancy hypoxic environment is optimal for embryo development, because it keeps a low level of metabolism and thereby minimizes the production of reactive oxygen species, as well as providing a beneficial effect on early placental development (Charnock-Jones 2002).…”

Section: Spontaneous Labour and Vaginal Deliverymentioning

confidence: 99%

“…Oxygen tension in the placenta continues to rise during the second trimester, in order to support the rapid fetal growth (Carter 2000) and then it decreases until term (Soothill et al 1986). The increased expression of key antioxidant enzymes and improvement of their activities helps the placenta adapt its defences to suit the hyperoxic conditions (Jauniaux et al 2000).…”

Section: Spontaneous Labour and Vaginal Deliverymentioning

confidence: 99%

Low abundance plasma proteins in labour

Wang¹,

Heesom²,

Phillips³

et al. 2012

Reproduction

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Every year, millions of births worldwide are complicated by prematurity or difficult post-term deliveries, resulting in a high incidence of perinatal mortality and morbidity. Our poor understanding of human parturition is a key reason for our inability to improve the management of preterm and post-term birth. In this study, we used proteomic techniques to look into protein changes in placental blood plasma obtained from women before or after spontaneous or induced labour, with vaginal or caesarean section deliveries. Our aim was to understand the basic mechanisms of human parturition regardless of whether the signals that trigger labour are of maternal and/or fetal origin. We found proteins from 33 genes with significantly altered expression profiles in relation to mode of labour and delivery. Most changes in labour occurred in proteins associated with 'immune and defence responses'. Although the signal transduction and regulation of these pathways varied among modes of delivery, hepatocyte nuclear factor 1 homeobox A emerged as a shared protein in the mechanism of labour. Moreover, several apolipoproteins such as apolipoprotein A-IV and APOE were found to change with labour, and these changes were also confirmed in maternal plasma. This study has identified significant protein changes in placental intervillous plasma with labour and has revealed several pathways related to human parturition.

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Amniotic gas values and acid-base status during acute maternal hyperoxemia and hypoxemia in the early fetal sheep

Cited by 9 publications

References 28 publications

Placental Ischemia and Resultant Phenotype in Animal Models of Preeclampsia

Placental Ischemia and Resultant Phenotype in Animal Models of Preeclampsia

Oxygen, a Key Factor Regulating Cell Behavior during Neurogenesis and Cerebral Diseases

Low abundance plasma proteins in labour

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