Public Defence: Oddrun Kristiansen

Master of Clinical Nutrition Oddrun Kristiansen at Institute of Clinical Medicine will be defending the thesis “Nutritional environment of the unborn child: The role of the human placenta in the maternal-fetal interaction; A study of uncomplicated pregnancies” for the degree of PhD (Philosophiae Doctor).

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Photo: Kari Bye, DUGG foto

Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.

Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Professor Teri Hernandez, University of Colorado, USA
  • Second opponent: Senior Consultant Agnethe Lund, Haukeland University Hospital
  • Third member and chair of the evaluation committee: Professor II Rune Svenningsen, University of Oslo

Chair of the Defence

Associate Professor Meryam Sugulle, University of Oslo

Principal Supervisor

Professor II Trond Melbye Michelsen, University of Oslo

Summary

The placenta regulates the fetal nutrient supply, which further influences fetal long-term health. Therefore, an insight into the placental function can be a key to improving the future health of the fetus, e.g., reducing the risk of obesity. Still, the placenta is regarded as the least understood of the human organs.

The objective of the thesis was to investigate human placental function in healthy, uncomplicated pregnancies. In paper 1, we aimed to investigate the placental transfer of taurine, an amino acid essential for the fetus, and the placental expression of the rate-limiting enzyme for taurine synthesis, cysteine sulfinic acid decarboxylase (CSAD). In paper 2, we explored the role of potential mediators in the association between maternal weight status (maternal body mass index [BMI] and gestational weight gain) and neonatal size (birthweight and neonatal fat mass). In paper 3, we aimed to investigate the association between maternal BMI and placental weight (PW).

Using the “4-vessel sampling method”, blood samples were collected from maternal and fetal circulations during planned cesarean sections. Blood flow measurements (Doppler ultrasound) were performed, and placental tissue samples were collected.  Data from the longitudinal STORK cohort was included in one paper.

Unexpectedly, we found that the placenta released taurine to both maternal and fetal circulations. Furthermore, CSAD gene expression was observed, suggesting placental taurine synthesis. The PW was a dominant mediator of maternal weight status in its association with neonatal size. The positive association between BMI and PW was found to plateau among overweight (BMI≥25 kg▪m^-2). A potential explanation was the effect of the adipose tissue hormone leptin, which was included in the analyses, indicating a placental-adipose tissue interaction. Finally, they observed a potential shift of placental insulin-signaling from the maternal to the fetal side of the placenta throughout gestation.

Additional information

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Published Dec. 2, 2022 10:31 AM - Last modified Dec. 14, 2022 1:51 PM