Serum brain-derived neurotrophic factor level in elderly women depression: a community-based study

Associations between inflammatory and neurological markers with quality of life and well-being in older adults

OBJECTIVES

Stressful experiences, poor self-rated health, and negative emotional states have been implicated with higher levels of inflammatory markers and lower levels of neurotrophic factors in some healthy adults and clinical populations, but these relationships are unclear in the elderly. This study aimed to identify the associations between systemic inflammatory and neurological markers with well-being and health-related quality of life (HR-QoL) in independently living elderly people.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

A total of 268 men and women aged ≥65 years living independently in retirement communities in Melbourne, Australia.

MEASURES

Questionnaires were used to assess HR-QoL [Short Form (SF)-36 version 2] and well-being (Personal Wellbeing Index). Serum inflammatory cytokines [interleukin (IL)-4, IL-6, IL-1β, IL-8, IL-10, tumor necrosis factor (TNF)-α, and high sensitive C-reactive protein (hs-CRP)] were standardised to Z-scores and used to calculate pro- and anti-inflammatory composite score and an overall composite inflammatory index. Plasma levels of the neurological markers amyloid β (1-40) and amyloid β (1-42), brain derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF), were also assessed.

RESULTS

No significant associations were found between any inflammatory or neurological marker with HR-OoL or well-being, with the exception that lower perceptions of the HR-QoL vitality subscale were associated with higher levels of hs-CRP [unstandardized beta-coefficient (β): -1.50; 95% CI: -2.53, -0.46; P = 0.004] and Z-scores in the pro-inflammatory composite score (β = -2.06; 95% CI: -3.49, -0.62; P = 0.005).

CONCLUSIONS/IMPLICATIONS

In elderly people residing in independent living retirement communities, there was no consistent evidence indicating that circulating inflammatory or neurological markers were associated with the key physical or mental HR-QoL domains or overall well-being. This suggests that these biomarkers may not be effective predictors in relatively healthy communities, and may be more beneficial in frail or clinical populations. Clinical Trials registry: Australian New Zealand Clinical Trials Registry (ACTRN12613001161718). http://www.anzctr.org.au/.

Low brain-derived neurotrophic factor levels in post-mortem brains of older adults with depression and dementia in a large clinicopathological sample

BACKGROUND

Disturbances in peripheral brain-derived neurotrophic factor (BDNF) have been reported in major depressive disorder (MDD). However, there are no studies measuring BDNF levels directly in post-mortem brains of older subjects with MDD and dementia. We aimed to verify if brain BDNF levels were lower in older adults with lifetime history of MDD with and without dementia.

METHODS

BDNF levels of post-mortem brains from 80 community-dwelling older individuals with lifetime MDD with and without dementia were compared with levels from 80 controls without lifetime MDD. Participants with no reliable close informant, or with prolonged agonal state were excluded. Lifetime MDD was defined as at least one previous episode according to the Structured Clinical Interview for DSM (SCID).

RESULTS

BDNF levels were lower in the MDD group with dementia than in participants with dementia and without MDD as confirmed by multivariate analysis adjusted for clinical and cardiovascular risk factors (ß = -0.106, 95%CI = -0.204; -0.009, p = 0.034). No difference was found in the group with MDD without dementia compared with their controls.

LIMITATIONS

The retrospective assessment of a lifetime history of depression may be subject to information bias and this study only establishes a cross-sectional association between lifetime history of MDD and lower levels of BDNF in patients with dementia.

CONCLUSIONS

In this community sample of older individuals, lower brain BDNF levels were found in cases with both lifetime MDD and dementia. Low BDNF levels could be a moderator to accelerated brain aging observed in MDD with dementia.

Serum brain-derived neurotrophic factor predicting reduction in pulse pressure after a one-hour rest in nurses working night shifts

Night shift work is associated with cardiovascular disease and central nervous system disorders in female nurses. Brain-derived neurotrophic factor (BDNF) exerts protective effects on neural and endothelial functions. This study examined the association between serum BDNF levels and pulse pressure after rest in female nurses working night shifts. In this study, blood samples were collected for BDNF measurement after a night shift when nurses had been working night shifts for three continuous weeks. Blood pressure was assessed before and after a one-hour morning rest within a week of resuming the night shift after one month without any night shift work. The pulse pressure of nurses (n = 48, age 29 ± 5 years) was significantly reduced (from 43 ± 7 to 41 ± 6 mmHg, P = 0.003) after rest, and serum BDNF were significantly and inversely correlated with pulse pressure changes (r = −0.435, P = 0.002). Higher serum BDNF was an independent factor for greater reduction in pulse pressure (95%CI = −0.609 ‒ −0.174, P = 0.001). Using a receiver operating characteristic curve analysis, serum BDNF >20.6 ng/mL predicted a pulse pressure reduction after a one-hour rest (sensitivity 66.7%, specificity 77.8%). In conclusion, higher serum BDNF predicted greater recovery of pulse pressure after a one-hour rest in female nurses after night shift work.

Antidepressive and BDNF effects of enriched environment treatment across ages in mice lacking BDNF expression through promoter IV

Reduced promoter IV-driven expression of brain-derived neurotrophic factor (BDNF) is implicated in stress and major depression. We previously reported that defective promoter IV (KIV) caused depression-like behavior in young adult mice, which was reversed more effectively by enriched environment treatment (EET) than antidepressants. The effects of promoter IV-BDNF deficiency and EET over the life stages remain unknown. Since early-life development (ED) involves dynamic epigenetic processes, we hypothesized that EET during ED would provide maximum antidepressive effects that would persist later in life due to enhanced, long-lasting BDNF induction. We tested this hypothesis by determining EET effects across three life stages: ED (0-2 months), young adult (2-4 months), and old adult (12-14 months). KIV mice at all life stages showed depression-like behavior in the open-field and tail-suspension tests compared with wild-type mice. Two months of EET reduced depression-like behavior in ED and young adult, but not old adult mice, with the largest effect in ED KIV mice. This effect lasted for 1 month after discontinuance of EET only in ED mice. BDNF protein induction by EET in the hippocampus and frontal cortex was also the largest in ED mice and persisted only in the hippocampus of ED KIV mice after discontinuance of EET. No gender-specific effects were observed. The results suggest that defective promoter IV causes depression-like behavior, regardless of age and gender, and that EET during ED is particularly beneficial to individuals with promoter IV-BDNF deficiency, while additional treatment may be needed for older adults.

Serum BDNF levels before and after the development of mood disorders: a case-control study in a population cohort

Serum levels of brain-derived neurotrophic factor (BDNF) are low in major depressive disorder (MDD), and were recently shown to decrease in chronic depression, but whether this is a trait or state marker of MDD remains unclear. We investigated whether serum BDNF levels decrease before or after the developments of MDD and other mood disorders through a case-control study nested in a cohort of 1276 women aged 75-84 years in 2008. Psychiatrists using the Structured Clinical Interview for DSM-IV identified incident cases of mood disorders at follow-up surveys in 2010 and 2012: 28 of MDDs, 39 of minor depressive disorders (minDDs) and 8 of minor depressive episodes with a history of major depressive episodes (minDEs with MDE history). A total of 106 representative non-depressed controls were also identified in the 2012 follow-up. We assayed BDNF levels in preserved sera of cases and controls at baseline and at follow-up. Serum BDNF levels at baseline in cases of MDD, minDD or minDE with MDE history were no lower than those in controls. The decrease in the serum BDNF level from baseline to follow-up was greater in cases of MDD or minDE with MDE history than in controls or cases of minDD. These results show that serum BDNF levels are not a trait marker of MDD in old women but appeared to be a state marker. The different changes in BDNF levels among diagnostic groups suggest that MDD has a pathophysiologic relation to minDE with MDE history, rather than to minDD.