Equine Uteroplacental Metabolism at Mid‐ and Late Gestation

Fowden, Abigail L.; Forhead, Alison J.; White, Kate; Taylor, Polly

doi:10.1111/j.1469-445x.2000.02067.x

Cited by 29 publications

(17 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, few animal studies have been published about the influence of gestational age on the V O 2 of uteroplacental and fetal tissues in vivo. These studies report different conclusions: in pregnant ponies, both uteroplacental and per-kilogram fetus uptakes of oxygen did not seem to change from mid-to late gestation (17). In sheep the fetal oxygen uptake per kilogram was instead increased at the end of gestation (2).…”

Section: Limitationsmentioning

confidence: 74%

Placental mitochondrial content and function in intrauterine growth restriction and preeclampsia

Mandò

Palma

Stampalija

et al. 2014

American Journal of Physiology-Endocrinology and Metabolism

166

132

View full text Add to dashboard Cite

Intrauterine growth restriction (IUGR) and pregnancy hypertensive disorders such as preeclampsia (PE) associated with IUGR share a common placental phenotype called “placental insufficiency”, originating in early gestation when high availability of energy is required. Here, we assess mitochondrial content and the expression and activity of respiratory chain complexes (RCC) in placental cells of these pathologies. We measured mitochondrial (mt)DNA and nuclear respiratory factor 1 ( NRF1) expression in placental tissue and cytotrophoblast cells, gene and protein expressions of RCC (real-time PCR and Western blotting) and their oxygen consumption, using the innovative technique of high-resolution respirometry. We analyzed eight IUGR, six PE, and eight uncomplicated human pregnancies delivered by elective cesarean section. We found lower mRNA levels of complex II, III, and IV in IUGR cytotrophoblast cells but no differences at the protein level, suggesting a posttranscriptional compensatory regulation. mtDNA was increased in IUGR placentas. Both mtDNA and NRF1 expression were instead significantly lower in their isolated cytotrophoblast cells. Finally, cytotrophoblast RCC activity was significantly increased in placentas of IUGR fetuses. No significant differences were found in PE placentas. This study provides genuine new data into the complex physiology of placental oxygenation in IUGR fetuses. The higher mitochondrial content in IUGR placental tissue is reversed in cytotrophoblast cells, which instead present higher mitochondrial functionality. This suggests different mitochondrial content and activity depending on the placental cell lineage. Increased placental oxygen consumption might represent a limiting step in fetal growth restriction, preventing adequate oxygen delivery to the fetus.

show abstract

Section: Limitationsmentioning

confidence: 74%

Placental mitochondrial content and function in intrauterine growth restriction and preeclampsia

Mandò

Palma

Stampalija

et al. 2014

American Journal of Physiology-Endocrinology and Metabolism

166

132

View full text Add to dashboard Cite

show abstract

“… Data derived from Comline & Silver, ; Reynolds et al., ; Ferrell, ; Fowden & Silver, ; DiGiacomo & Hay, ; Fowden et al., ; Fowden, Forhead et al., ; Fowden, Taylor et al Aldoretta & Hay, . …”

Section: Oxygenmentioning

confidence: 99%

“…Oxygen consumption by the combined uteroplacental tissues increases by 25–50% between mid‐gestation and late gestation in sheep and horses but not in pigs when expressed per kg wet weight (Bell, Kennaugh, Battaglia, Makowski, & Meschia, ; Fowden, Forhead, White, & Taylor, ; Fowden, Taylor, White, & Forhead, ; Molina, Meschia, Battaglia, & Hay, ; Reynolds, Ford, & Ferrell, ). In contrast, when values are calculated per gram dry weight of placenta alone, there is little change in placental O 2 consumption during the second‐half of gestation in sheep (Vatnick & Bell, ).…”

Section: Oxygenmentioning

confidence: 99%

“…Consequently, the amount of O 2 consumed by the uteroplacental tissues as a proportion of the total uterine O 2 uptake alters with gestational age depending on the species. For instance, in sheep, the percentage of uterine O 2 uptake used by the uteroplacental tissues decreases from 80% to 40–45% between mid‐gestation and late gestation, whereas, in horses and pigs, this percentage remains at 55% and 65%, respectively, throughout the second‐half of gestation (Bell et al., ; Fowden, Forhead et al., ; Fowden, Taylor et al. ; Molina et al., ; Reynolds et al., ).…”

Section: Oxygenmentioning

confidence: 99%

See 1 more Smart Citation

Placental metabolism: substrate requirements and the response to stress

Vaughan

Fowden

2016

Reprod Domestic Animals

View full text Add to dashboard Cite

The placenta is a dynamic, metabolically active organ with significant nutrient and energy requirements for growth, nutrient transfer and protein synthesis. It uses a range of substrates to meet its energy needs and has a higher rate of oxygen (O 2 ) consumption than many other foetal and adult tissues. Placental metabolism varies with species and alters in response to a range of nutritional and endocrine signals of adverse environmental conditions. The placenta integrates these signals and adapts its metabolic phenotype to help maintain pregnancy and to optimize offspring fitness by diversifying the sources of carbon and nitrogen available for energy production, hormone synthesis and foeto-placental growth. The metabolic response of the placenta to adversity depends on the nature, severity and duration of the stressful challenge and on whether the insult is maternal, placental or foetal in origin. This review examines placental metabolism and its response to stresses common in pregnancy with particular emphasis on farm species like the sheep. It also considers the consequences of changes in placental metabolism for the supply of O 2 and nutrients to the foetus.

show abstract

“…Uteroplacental uptakes of the specific progestagens from, or their outputs into, the umbilical and uterine circulations were calculated by the Fick principle as the product of umbilical or uterine plasma flow and the venous-arterial (V-A) or arterial-venous (A-V) concentration difference in each progestagen across the respective circulation as defined by the following equations [16]:…”

Section: Calculationsmentioning

confidence: 99%

Ontogeny of Uteroplacental Progestagen Production in Pregnant Mares During the Second Half of Gestation1

Ousey

Forhead

Rossdale

et al. 2003

Biology of Reproduction

View full text Add to dashboard Cite

In pregnant mares during late gestation, little, if any, progesterone (P 4 ) is found in the maternal circulation. Hence, quiescence of the equine uterus is believed to be maintained by metabolites of pregnenolone and P 4 known as progestagens, which are produced by the uteroplacental tissues. However, little is known about the ontogeny, distribution, or actual rates of uteroplacental progestagen production in pregnant mares and their fetuses during the second half of pregnancy. Therefore, the present study measured the rates of uteroplacental uptake and output of eight specific progestagens in chronically catheterized, pregnant pony mares from 180 days to term. No significant uteroplacental uptake of any of the eight individual progestagens was observed from the uterine circulation. In contrast, significant uteroplacental uptake was observed for five of the eight individual progestagens from the umbilical circulation, and the uptakes increased toward term. The major uteroplacental progestagen outputs were 5␣-pregnane-3,20-dione (5␣DHP) and 20␣-hydroxy-5␣-pregnan-3-one (20␣5P). These were released into both the umbilical and uterine circulations at rates that increased toward term. The majority of the total uteroplacental 20␣5P output was distributed into the uterine circulation at all gestational ages studied. In contrast, distribution of the total uteroplacental 5␣DHP output switched from preferential delivery into the uterine circulation before 220 days of gestation to release predominantly into the umbilical circulation after 260 days. These findings demonstrate that uteroplacental progestagen production changes during the second half of gestation, which may have important implications for the maintenance of pregnancy and the onset of labor in the mare. placenta, pregnancy, progesterone, steroid hormones

show abstract

Equine Uteroplacental Metabolism at Mid‐ and Late Gestation

Cited by 29 publications

References 16 publications

Placental mitochondrial content and function in intrauterine growth restriction and preeclampsia

Placental mitochondrial content and function in intrauterine growth restriction and preeclampsia

Placental metabolism: substrate requirements and the response to stress

Ontogeny of Uteroplacental Progestagen Production in Pregnant Mares During the Second Half of Gestation1

Contact Info

Product

Resources

About