Biomarkers and Depressive Symptoms in Older Women with and without Cognitive Impairment

A number of biological markers have been implicated in late life depression with inconsistent results. The present study examined the relationship between several serum based biomarkers and symptoms of depression in a sample of elderly women with AD or cognitively intact. Methods 171 females (58 with AD and 113 cognitively intact) were recruited from the Longitudinal Research Cohort of the Texas Alzheimer’s Research and Consortium (TARC). Stepwise regressions were conducted with GDS total and subscales and a panel of biomarkers (CRP, IL-10, IL-1α, TNF-α, ICAM-1, BDNF, and MIF). ApoE4 status was coded (carrier or non-carrier), and the results were analyzed by cognitive status (AD or controls). Results: None of the biomarkers significantly predicted total GDS score for AD cases, controls or sample as a whole. For the Controls, ICAM significantly predicted Dysphoria and level of Apathy. Among AD patients, MIF, ICAM, and CRP, were significantly associated with Apathy. MIF and ICAM were inversely associated with reported Apathy. CRP was positively associated with Apathy. CRP was also positively related to level of perceived Cognitive Impairment. Conclusions: The present study was one of the first to examine biomarkers related to depression symptoms in elderly women with AD and normal controls. For Controls ICAM alone predicted level of apathy. In the AD group, MIF, CRP, and ICAM were significantly associated with apathy. More research examining the relationship between biomarkers and depression is needed in older patients with and without cognitive impairment across genders.

Higher Groundwater Selenium Exposure Is Associated with Better Memory: A Project FRONTIER Study

Background: Exposure to elements in groundwater (toxic or beneficial) is commonplace yet, outside of lead and mercury, little research has examined the impact of many commonly occurring exposures on mental abilities during the aging process. Selenium has antioxidant properties as part of the glutathione peroxidase system and may have protective effects on memory abilities. Objectives: To investigate the relationship of groundwater selenium exposure to neuropsychological status. Method: Analysis of data from 484 participants (148 men and 336 women) of Project FRONTIER, a community-based participatory research study of the epidemiology of health issues of rural-dwelling adults and elders. Results: Estimated selenium exposure (current and long-term) was specifically related to memory functioning without relation to other neurocognitive domains. The significant, positive link between selenium and memory (Immediate and Delayed) scores held regardless of APOE4 status as well as when the sample was restricted to only those without cognitive dysfunction. Current selenium was also associated with significantly reduced risk of cognitive decline prospectively. Conclusions: Higher selenium levels were associated with better memory functioning as well as reduced risk of cognitive decline among this community-based sample. Given the antioxidant properties of selenium, and the well-documented link between oxidative stress and the development of cognitive dysfunction and Alzheimer’s disease, additional research is necessary to determine the utility of groundwater selenium monitoring as a potential population-wide prevention effort against Alzheimer’s disease.

Biomarkers and Depressive Symptoms in a Sample of Cognitively Intact and Alzheimer’s Disease Elderly Males

Serum-based biomarkers and GDS-30 score and subscales of depressive symptoms were examined in a cross-sectional sample of 81 elderly men drawn from the TARCC cohort. Measurements included neuropsychological assessment and serum. Thirty three patients met consensus diagnosis for probable AD and forty eight were cognitively intact. Although initial regression analysis of all subjects showed significant relationships between depression and specific biomarkers, analyses based on diagnosis indicated that none of the biomarkers were significantly associated with depression among the controls. Among AD males MIF was significantly associated with total GDS scores and subscales of dysphoria, meaninglessness, and cognitive impairment. TNF-α was significantly associated with the apathy in AD males. Higher levels of MIF were associated with less depression in AD men. TNF-α was positively associated with degree of apathy. This study suggests the importance of cognitive status, gender and subtypes of depression when investigating biomarkers and depression in the elderly.