The etiology of many gestational disorders is still unknown. However, insufficient trans-placental passage of nutrients and wastes due to poor placentation is characteristic of several pathologies and may be due, in part, to altered function of placental mitochondria. Mitochondrial activity is essential in pregnancy because it sustains the metabolic activity of the placenta throughout gestation. Exposure to stressors that perturb processes governing placentation, including maternal drug use, can negatively impact fetal development.
Cannabis use is prevalent during pregnancy. The psychoactive constituent, delta-9-tetrahydrocannbinol (THC), can cross the placenta to affect placental and fetal physiology. Importantly, cannabinoid receptors have been reported on trophoblast cells, and on mitochondria which are abundant in placentae. It has been reported that THC may target the mitochondria in various tissue types, including placental tissue, and alter its function. However, few studies have addressed the physiological control of mitochondria within the placenta, an organ that is critical for fetal growth and pregnancy maintenance.
I investigated the role of mitochondria in trophoblast differentiation and syncytialization using rotenone, a complex I inhibitor. Subsequently, I investigated the role of THC on two important aspects of placentation – invasion and syncytialization – using placental trophoblast cells HTR8/SVneo and BeWo, respectively. In response to rotenone and THC, there was increased ROS production, oxidative stress, and altered transcriptional markers favouring mitochondrial fragmentation. Treatment with 20µM THC for 48 hours led to reduced mitochondrial respiration, ATP production and loss of mitochondrial membrane polarity. Critically, these THC-induced mitochondrial changes occurred concomitant with evidence of reduced trophoblast invasion and syncytialization. Furthermore, THC exposure reduced levels of human chorionic gonadotropin, human placental lactogen and insulin-like growth factor 2, which are growth factors necessary for fetal development. Placental mitochondrial dysfunction, particularly when THC-induced, may be critical in a range of gestational disorders which have important implications for maternal and fetal/offspring health. / Dissertation / Doctor of Philosophy (Medical Science) / Cannabis is commonly used by pregnant women. Fetal exposure to cannabis and its components can impair fetal growth and neurological development. These negative fetal outcomes may be the result of poor placental formation, due to placental cell exposure to cannabis and its psychoactive component, delta-9-tetrahydrocannabinol (THC). Importantly, THC can also target intracellular organelles, like the mitochondria which are known as the “powerhouses” of the cell. Few studies have investigated the direct effects of THC on placental development. The purpose of this study was to determine how THC exposure to placental cells may alter their function. We found that THC impaired processes that allow placental attachment to the uterus and form a protective barrier, and compromised mitochondrial function, which are important for placental formation. These findings serve to inform scientists and doctors, thus stimulating the creation of new ideas and methods to further explore the impact of THC on pregnancy outcomes.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25870 |
| Date | January 2020 |
| Creators | Walker, O'Llenecia |
| Contributors | Raha, Sandeep |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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