Research Reports - Associations between brain-derived neurotrophic factor, memory impairment, functional cognition, and depressive symptoms following TBI
Neurorehabil Neural Repair. 2015 Aug 13. pii: 1545968315600525. [Epub ahead of
Failla MD(1), Juengst SB(2), Arenth PM(2), Wagner AK(3).
BACKGROUND: Traumatic brain injury (TBI) often leads to mood and cognitive
complications, affecting functional recovery. Understanding neurobiological
alterations common in post-TBI depression (PTD) and cognition may identify novel
biomarkers for TBI complications. Brain-derived neurotrophic factor (BDNF) is a
likely target based on evidence of reduced BDNF signaling in experimental TBI and
depression models and its role in learning and memory.
OBJECTIVE: To evaluate BDNF as a biomarker for PTD, cognitive impairment, and
functional cognition in a prospective cohort with severe TBI.
METHODS: Participants with TBI (n = 113) were evaluated for PTD (Patient Health
Questionnaire-9 [PHQ-9]), cognitive impairment (cognitive composite score), and
functional cognition (Functional Independence Measure-Cognition, FIM-Cog). BDNF
levels were measured in cerebrospinal fluid and serum at 0 to 6 days postinjury
and in serum at 6 and 12 months postinjury.
RESULTS: Serum BDNF was reduced after TBI versus controls at all time points.
Acute serum BDNF positively correlated with memory composites (6 months: r =
0.43, P = .019, n = 30; 12 months: r = 0.53, P = .005, n = 26) and FIM-Memory
scores (6 months: r = 0.35, P = .019, n = 45; 12 months: r = 0.38, P = .018, n =
38). Acute serum BDNF negatively correlated with 12-month PHQ-9 scores (r =
-0.38; P = .044; n = 29). At 12 months, chronic serum BDNF tended to be lower in
participants with PTD (P = .07) and correlated with PHQ-9 scores (r = -0.41; P =
.019; n = 32).
CONCLUSIONS: Acute BDNF associations with memory recovery may implicate
hippocampal damage/degeneration. Comparatively, BDNF associations with PTD status
were not as strong as associations with PTD severity. Further investigation may
delineate longitudinal BDNF patterns, and BDNF responsive treatments, reflecting
mood and cognitive recovery following TBI.