The Effects of Prolonged Stress and APOE Genotype on Memory and Cortisol in Older Adults

Abstract

Background-Chronic elevations in cortisol associated with prolonged stress have been associated with memory loss, as has the APOE-ε4 genotype. The combined effects of stress and APOE status on memory and cortisol in humans have not been studied.

ApoE2 Exaggerates PTSD-Related Behavioral, Cognitive, and Neuroendocrine Alterations

“…PTSD has also been associated with diminished hippocampal volume (Smith, 2005) and function (Shin et al, 2006). Stress can significantly affect memory, and evidence suggests that stress and APOE interact to affect memory (Peavy et al, 2007). We show that when challenged with a memory test immediately after a fear stress, mice with E2 demonstrate relative impairments in long-term hippocampus-dependent memory.…”

Comorbid Depression Is Associated with an Increased Risk of Dementia Diagnosis in Patients with Diabetes: A Prospective Cohort Study

“…Biologic effects of depression include hypothalamic pituitary axis dysregulation, which results in chronic elevation of glucocorticoid production, and impaired negative feedback. 4 High cortisol levels may damage brain regions involved in cognition, such as the hypothalamus, 35,36 as well as decrease neurogenesis in key brain areas 37 . Chronic and recurrent depression have been shown to be associated with hippocampal atrophy.…”

Lower morning to evening cortisol ratio is associated with cognitive impairment in men but not women: An analysis of 733 older subjects of the cross-sectional KORA-Age study

“…Previous studies have reported that MCI individuals showed increased cortisol levels compared to cognitively healthy subjects (Lee et al, 2007;Lind et al, 2007;Lupien et al, 1998) while others found no significant differences (Wolf et al, 2002). This is particularly important as MCI is an established risk factor for cognitive decline (Peavy et al, 2007). Subtypes of MCI have been associated with morphological and functional changes in certain brain structures (Qiu et al, 2009) which may modulate the HPA axis regulation, thus affecting circadian cortisol secretion (McEwen, 2008).…”