Decreased Serum Brain-Derived Neurotrophic Factor Levels in Elderly Korean with Dementia

Abstract

ObjectiveThe primary purpose of this study was to investigate the differences in the serum brain-derived neurotrophic factor (BDNF) level between elderly Korean people over 65 years with and without dementia.Methods171 individuals over 65 years were enrolled in this study. Screening for cognitive impairments was carried out using the Mini-Mental Status Examination-Korean version (MMSE-KC). One hundred thirty-two subjects scored below 1.5 standard deviations (SD) of the mean MMSE-KC score, and these were evaluated using the Consortium to Establish a Registry for Alzheimer's Disease, Korean version (CERAD-K) and the Geriatric Depression Scale (GDS). The Clinical Dementia Rating Scale (CDRS) and the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) diagnostic criteria were used for further evaluation. Subjects with a CDRS score of 1 or higher were classified as having Alzheimer's disease (AD), and subjects with a CDRS score of 0.5 were classified as having a mild cognitive impairment (MCI). Subjects with a CDRS score of 0 were classified as having aging-associated cognitive decline (AACD). Serum BDNF levels were analyzed using the enzyme-linked immunosorbent assay (ELISA) method.ResultsThe serum BDNF levels were significantly lower in the subjects with MCI and AD compared with the healthy controls (p<0.01). A significant correlation was found between the total MMSE-KC score and serum BDNF level (r=0.295; p<0.01). However, no significant correlation was observed between the severity of MMSE-KC and the total GDS score. A significant difference was found in the total score of GDS between the AACD group and subjects with AD (p<0.05).ConclusionThis study suggested that BDNF might be involved in the pathophysiology of cognitive decline in elderly people.

The involvement of BDNF, NGF and GDNF in aging and Alzheimer's disease

“…Another studies have shown BDNF levels diminished in AD patients as compared to controls [32][33][34][35][36][37]. Lee (2009) also observed a BDNF levels decrease in both AD and MCI patients [38]. Other results showed increase in the BDNF levels in these patients.…”

Alzheimer’s Disease and Diabetes

“…This indicates that decreased insulin signaling resulting in reduced BDNF production may be a contributing factor in AD development. In accordance, AD patients have decreased serum BDNF concentrations compared to healthy, elderly subjects [237][238][239][240][241] while reduced BDNF levels were associated with decreased cognitive performance in healthy individuals [242].…”

Depression and Brain-derived Neurotrophic Factor Levels in Alzheimer's Disease

“…The results from the previous study, however, were limited by the small number of AD patients assessed (N = 11). Another study found no difference in BDNF levels when comparing severely depressed patients with those not severely depressed [13]. That study compared patients with age associated cognitive decline, MCI and AD and used 20 as the cutoff for severe depression.…”

“…In one such study, a negative correlation between BDNF serum concentrations and level of depression as measured by the Geriatric Depression Scale has been reported [12]. In contrast, a study of elderly Korean AD patients found no differences in serum BDNF levels between subjects scoring high on the GDS (≥20) and those scoring low on the GDS [13]. The current study investigated the relationship between serum BDNF concentrations and level of depression as measured by the GDS in a sample of Alzheimer's patients to help clarify this relationship.…”