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Member of: Barrett, The Honors College Thesis/Creative Project Collection

Cognitive efficacy of three bioidentical, endogenously circulating estrogens given as hormone therapy: Extending prior findings and navigating into unchartered territory

Description

Women are now living longer than ever before, yet the age of spontaneous menopause has remained stable. This results in an increasing realization of the need for an effective treatment of cognitive and physiological menopausal and post-menopausal symptoms. The most common estrogen component of hormone therapy, conjugated equine estrogens (CEE; Premarin) contains many estrogens that are not endogenous to the human body, and that may or may not be detrimental to cognition (Campbell and Whitehead, 1977; Engler-Chiurazzi et al., 2011; Acosta et al., 2010). We propose the use of a novel treatment option in the form of a naturally-circulating (bioidentical) estrogen called estriol. Due to estriol’s observed positive effects on synaptic functioning and neuroprotective effects in the hippocampus (Ziehn et al., 2012; Goodman et al., 1996), a brain structure important for spatial learning and memory, estriol is promising as a hormone therapy option that may attenuate menopausal- and age- related memory decline. In the current study, we administered one of the three bioidentical estrogens (17β-Estradiol, 4.0 µg/day; Estrone, 8.0 µg/day; Estriol, 8.0 µg/day) or the vehicle polyethylene glycol by subcutaneous osmotic pump to ovariectomized Fisher-344 rats. We compared these groups to each other using a battery of spatial learning tasks, including the water radial-arm maze (WRAM), Morris water maze (MM), and delayed-match-to-sample maze (DMS). We found that all estrogens impaired performance on the WRAM compared to vehicle, while 17β-estradiol administration improved overnight forgetting performance for the MM. The estriol group showed no cognitive enhancements relative to vehicle; however, there were several factors indicating that both our estriol and estradiol doses were too high, so future studies should investigate whether lower doses of estriol may be beneficial to cognition.

ContributorsStonebarger, Gail Ashley (Author) / Bimonte-Nelson, Heather (Thesis director) / Knight, George (Committee member) / Engler-Chiurrazzi, Elizabeth (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)

Created2015-05

The Importance of Studying Interactions With Ovarian Hormones: Implications for Depressive Symptoms in Premenopausal and Menopausal Women

Description

The relevance of depression in the clinical realm is well known, as it is one of the most common mental disorders in the United States. Clinical depression is the leading cause of disease for women worldwide. The sex difference in depression and anxiety has guided the research of not just recent studies but older studies as well, supporting the theory that gonadal hormones are associated with the mechanisms of emotional cognition. The scientific literature points towards a clear correlative relationship between gonadal hormones, especially estrogens, and emotion regulation. This thesis investigates the neural pathways that have been indicated to regulate mood and anxiety. Currently, the research points to the hypothalamic-pituitary-adrenal axis, which regulates the stress response through its ultimate secretion of cortisol through the adrenal cortex, and its modulated response when exposed to higher levels of estrogen. Another mechanism that has been investigated is the interaction of estrogen and the serotonergic system, which is noteworthy because the serotonergic system is known for its importance in mood regulation. However, it is important to note that the research seeking to determine the neurobiological underpinnings of estrogen and the serotonergic system is not expansive. Future research should focus on determining the direct relationship between cortisol hypersecretion and estrogens, the specific neurobiological effects of serotonergic receptor subtypes on the antidepressant actions of estrogens, and the simultaneous effects of the stress and serotonergic systems on depressive symptoms.

ContributorsArroyo, Mariana (Author) / Bimonte-Nelson, Heather (Thesis director) / Jurutka, Peter (Committee member) / School of International Letters and Cultures (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)

Created2021-05

The Gender Differences in Heart Disease and the Cardiovascular Benefits of Estrogen

Description

Heart disease is the number one killer of men and women in the world. The incidence of cardiovascular disease is known to be much higher in men than women until around the ages of 60-75 years, when the occurrence of the disease becomes approximately equal in both sexes. Additionally, the occurrence of heart disease is significantly lower in premenopausal women than postmenopausal women. Since men have a higher risk for heart disease than women until 10-15 years after the average age of menopause and postmenopausal women have a higher risk of cardiovascular disease than premenopausal women, it is hypothesized that endogenous estrogen exposure throughout the fertile period of a woman's life postpones the onset of cardiovascular disease. Research shows estrogen has beneficial effects on the cardiovascular system by regulating multiple metabolic processes including lipid metabolism, vasodilation, nitric oxide synthesis, cytochrome c apoptosis, and mitochondrial antioxidant production. Though estrogen has been found to have cardiovascular benefits on individual metabolic processes, the treatment of synthetic estrogen on postmenopausal women and men to reduce the overall risk of heart disease is very controversial. The controversy of synthetic estrogen is partially due to the fact that most studies done using estrogen replacement therapy on postmenopausal women and men resulted in either no effects or harmful effects on the cardiovascular system. Hormone replacement therapy has also been associated with a higher risk of multiple medical conditions, especially venous thromboembolism and breast cancer. This review will explore these topics and consider the costs and benefits of estrogen replacement therapy.

ContributorsWeng, Tina Savanna (Author) / Hyatt, J.P. (Thesis director) / Kingsbury, Jeffrey (Committee member) / Dean, The College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)

Created2019-05