Discipline: Biological Sciences
Subcategory: Physiology and Health
Joshua Cotton - Tougaloo College
Co-Author(s): Sydney Murphy, University of Mississippi Medical Center
Preeclampsia is a pregnancy specific disease that is characterized as hypertension and/or new-onset proteinuria and visual/cerebral disturbances after the 20th week of pregnancy. A substantial amount of evidence suggests that abnormal spiral artery remodeling resulting in placental ischemia/hypoxia is the initiating event in the disease process, however, the factors contributing to the reduced vascular remodeling are unknown. The placenta serves as an interface between the mother and the growing fetus ensuring proper nutrient and oxygen delivery. The uterine spiral arteries play a pivotal role in nutrient delivery and undergo remodeling into large, dilated vessels. Incomplete remodeling of the maternal spiral arteries, thought to result from shallow trophoblast invasion, is hypothesized as the key feature triggering preeclampsia. However, the factors involved in the abnormal placental vascular remodeling are currently unknown and therefore a better understanding of the factors contributing to the incomplete remodeling is key to understanding the etiology of preeclampsia. One of the major metabolites of the cytochrome P450 (CYP450) pathway, 20-hydroxyeicosatetraenoic acid (20-HETE), is reported to contribute to migration and proliferation of vascular smooth muscle cells (VSMC) in vitro. AA metabolism is reported to be altered within the preeclamptic placenta, suggesting alterations in the delicate balance of the metabolism of AA could play an important role in the altered vascular remodeling seen in preeclampsia. Placentas and kidneys were harvested from pregnant female rats on Day 19 of pregnancy, quickly frozen in liquid nitrogen, and stored in -80C. Microsomes and proteins were isolated from both placenta and kidneys for western blotting and measurement of eicosanoid production by mass spectrometry. The arachidonic acid-cytochrome P450 metabolite profile is different between pregnant rat strains. Specifically, 20-HETE production is elevated in the kidney and placenta of CYP4A1 Tg pregnant rats during late gestation. Results: 20-HETE production was increased in the renal cortex of CYP4A1 Transgenic rats on gestational day 19 compared to Sprague Dawley (SD) and Dahl SSJr rats (A). Total HETEs were increased in CYP4A1 Tg pregnant rats. 20-HETE production was increased in the renal outer medulla of CYP4A1 Transgenic rats on gestational day 19 compared to Sprague Dawley (SD) and Dahl SSJr rats (A). Total HETEs were increased in CYP4A1 Tg pregnant rats.
Future directions include: Measure maternal blood pressure and proteinuria increase Ns in each group. Histological analysis of localization of CYP4A and trophoblast cells. Measure metabolites of the cyclooxygenase and lipoxygenase pathways.
Funder Acknowledgement(s): National Institues of Health
Faculty Advisor: Sydney Murphy, firstname.lastname@example.org
Role: I was responsible for western blotting and reading papers that were close to the experiments that we were conducting. I was also responsible for homogenizations and cytokeratin staining.