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Today, The Visible Embryo is linked to over 600 educational institutions and is viewed by more than 1 million visitors each month. The field of early embryology has grown to include the identification of the stem cell as not only critical to organogenesis in the embryo, but equally critical to organ function and repair in the adult human. The identification and understanding of genetic malfunction, inflammatory responses, and the progression in chronic disease, begins with a grounding in primary cellular and systemic functions manifested in the study of the early embryo.

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Pregnancy Timeline by SemestersFetal liver is producing blood cellsHead may position into pelvisBrain convolutions beginFull TermWhite fat begins to be madeWhite fat begins to be madeHead may position into pelvisImmune system beginningImmune system beginningPeriod of rapid brain growthBrain convolutions beginLungs begin to produce surfactantSensory brain waves begin to activateSensory brain waves begin to activateInner Ear Bones HardenBone marrow starts making blood cellsBone marrow starts making blood cellsBrown fat surrounds lymphatic systemFetal sexual organs visibleFinger and toe prints appearFinger and toe prints appearHeartbeat can be detectedHeartbeat can be detectedBasic Brain Structure in PlaceThe Appearance of SomitesFirst Detectable Brain WavesA Four Chambered HeartBeginning Cerebral HemispheresFemale Reproductive SystemEnd of Embryonic PeriodEnd of Embryonic PeriodFirst Thin Layer of Skin AppearsThird TrimesterSecond TrimesterFirst TrimesterFertilizationDevelopmental Timeline
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Home | Pregnancy Timeline | News Alerts |News Archive Sep 20, 2013

 

Women who smoke during pregnancy have been found to have as much as
a 33 percent lower rate of preeclampsia for reasons that are unclear. 

This study, the first to look at the effects of carbon monoxide (CO) on the placenta in mice, found that exposing the animals to inhalable CO increased blood flow and vascular growth
in the developing placenta, created more, bigger, and stronger connections to the uterus,
a process that provides more oxygen and nutrients to the fetus. ).






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Carbon monoxide effective preeclampsia treatment, (?) prevention

Preeclampsia (PE) is a high blood pressure disorder that occurs during pregnancy which can cause illness or death for the fetus and mother. There is currently no cure except to deliver the fetus, perhaps prematurely, or removal of the placenta.

Women who smoke during pregnancy have been found to have as much as a 33 percent lower rate of preeclampsia for reasons that are unclear. A new study using an animal model to mimic key effects of PE in humans, and led by Graeme Smith of Queen's University, Canada, may help explain the lower incidence of PE in some smokers.

The study also suggests a therapy that could offer similar protection against PE with none of smoking's well-known risks.

The article "Chronic Carbon Monoxide Inhalation During Pregnancy Augments Uterine Artery Blood Flow and Uteroplacental Vascular Growth in Mice," appears in the Articles in PresS edition of the American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology, published by the American Physiological Society. It is available online at http://bit.ly/18tQcyL.

Background
Research has found that, compared with that of healthy pregnant women, the breath of women who are diagnosed with PE contains significantly lower levels of carbon monoxide (CO), one of the combustible elements in cigarettes and which is not present in smokeless tobacco. Although toxic at high levels, low levels of CO are produced naturally by the body and have positive effects.


This study, the first to look at the effects of CO on the placenta in mice, found that exposing the animals to inhalable CO increased blood flow and vascular growth in the developing placenta, created more, bigger, and stronger connections to the mother's uterus, a process that provides more oxygen and nutrients to the fetus.

And, since PE is a multifaceted disorder that begins with abnormal placental development before progressing to maternal disease, the results also suggest the possibility of preventing or treating early PE in humans with controlled CO dosages.


Methodology
Beginning on gestation day, pregnant female mice were placed in a sealed chamber with as much food and water as they wanted and exposed to CO, either chronically or acutely twice during gestation, at levels that allowed mouse CO blood levels to reach levels comparable to a one-pack-per-day female smoker.

Maternal weight, live fetuses, fetal resorptions, and implantation sites were compared to control mice.

Doppler analysis was performed on day 5 (baseline), 10 (when placental structure has formed and blood begins to cross the placenta to the fetus), and 14 (when blood velocity is well-established and fetal vasculature begins). Mice were then anesthetized and a cast was made of the entire uterus and blood vessels, then mounted and three-dimensionally imaged by micro-CT.

Results
Exposure to CO either continuously or in specific doses did not affect maternal weight (used as a measure of health) or litter size. Compared to controls, CO exposure did lead to increased vessel diameter, a significant increase in the number of radial artery branches, and significantly higher maternal blood flow.

Importance of the Findings


The study, according to Dr. Smith, confirms for the first time in vivo [live pregnancy] carbon monoxide (CO) has a beneficial effect at the placental level.

It also provides an explanation for the lower incidence of PE among smokers, whose CO levels are higher.

Positive changes in placental development in mice breathing additional CO – and earlier studies in the Smith lab showing these levels of CO had no negative effect on the developing fetus — suggest a potential role for CO inhalations in preventing PE in patients at risk (perhaps because of severe PE in a previous pregnancy) or in attenuating early stage PE, preventing abnormal placental development from progressing to maternal disease.


Abstract
End- tidal breath carbon monoxide (CO) is abnormally low in women with preeclampsia (PE), while women smoking during pregnancy have shown an increase in CO levels and a 33% lower incidence of PE. This effect may be in part due to lowered sFLT1 plasma levels in smokers, and perhaps low- level CO inhalation can attenuate the development of PE in high risk women. Our previous work showed maternal chronic CO exposure (< 300ppm) throughout gestation had no maternal or fetal deleterious effects in mice. Our current study evaluated the uteroplacental vascular effects in CD-1 maternal mice who inhaled CO (250ppm) both chronically, gestation day (GD) 0.5 to 18.5, and acutely, 2.5hrs on each of GD 10.5 and 14.5. We demonstrated, using micro-ultrasound measurements of blood velocity and micro-computed tomography imaging of the uteroplacental vasculature, that chronic maternal exposure to CO doubled uterine artery blood flow and augmented uteroplacental vascular diameters and branching. This finding may be of benefit to women with PE, as they exhibit uteroplacental vascular compromise. The ratio of VEGF protein to its FLT1 receptor was increased in the placenta suggesting a shift to a more angiogenic state, however maternal circulating levels of VEGF, sFLT1, and their ratio were not significantly changed. Doppler blood velocities in the maternal uterine artery and fetal umbilical artery and vein were unaltered. This study provides in vivo evidence that chronic inhalation of 250ppm CO throughout gestation augments uterine blood flow and uteroplacental vascular growth, changes that may protect against the subsequent development of preeclampsia.

Study Team
In addition to Dr. Smith, the study team consisted of Carolina Venditti, Casselman and Malia SQ Murphy, also of Queen's University; S. Lee Adamson of Mount Sinai Hospital, Toronto, and the University of Toronto; and John G. Sled of the Hospital for Sick Children's Mouse Imaging Centre and the University of Toronto.

Physiology is the study of how molecules, cells, tissues, and organs function in health and disease. Established in 1887, the American Physiological Society (APS) was the first US society in the biomedical sciences field. The Society represents more than 11,000 members and publishes 14 peer-reviewed journals with a worldwide readership.

Original press releas: http://www.the-aps.org/mm/hp/Audiences/Public-Press/For-the-Press/releases/13/28.html