Brain-Derived Neurotrophic Factor as a Clinical Biomarker in Predicting the Development of Post-Stroke Depression: A Review of Evidence

Abstract

Studying the relationship between brain-derived neurotrophic factor (BDNF) and post-stroke depression (PSD) may help determine the potential for depression in stroke patients at the earliest stage possible. Current research has identified changes in BDNF levels in PSD patients. Thus, this article was intended as a review of evidence with respect to changes in the expression of BDNF in patients with PSD by integrating extant findings. We conducted a search in the electronic databases PubMed, EMBASE, and PsycINFO (all records from January 1, 2000, through October 20, 2020) using keywords: “brain-derived neurotrophic factor OR BDNF,” “post-stroke depression OR PSD,” “expression level,” “association,” and “relationship.” Returned articles were considered for inclusion in this review if they were empirical studies investigating the association between BDNF expression and PSD. Seven original papers were selected for review and revealed inconsistent findings. Five out of seven studies reported a significant decrease in BDNF levels in PSD patients at a certain stage (most likely the early stage) of stroke after admission, whereas the other two showed contrasting findings. Overall, this review reveals associations between changes in serum BDNF levels and depression following stroke. Whether serum BDNF levels, especially in the early phase of stroke, can be a potentially effective biomarker for predicting the risk of subsequent PSD development is still open to debate.

Microglia Involves in the Immune Inflammatory Response of Poststroke Depression: A Review of Evidence

“…It binds to tyrosine kinase receptor B (TrkB) and plays a crucial neurotrophic role [58][59][60][61]. Its functions include nourishing damaged neurons, regulating neural plasticity, depicting a vital role in the survival, differentiation, growth, and postinjury repair of neurons, and participating in the initiation and development of depression, regarded as a landmark indicator for the diagnosis of depression [62,63]. Many studies have revealed that the expression of BDNF and its high-affinity receptor TrkB protein in the thalamus decrease after PSD, indicating PSD occurrence is tightly associated with BDNF level, and the lesser the production of BDNF, the more likely PSD will occur [64,65].…”

Factors Affecting Post-Stroke Depression in Acute Ischemic Stroke Patients after 3 Months

“…The association between neurotransmitters and PSD has not yet been clearly demonstrated. The results of previous studies on the association between a reduction in BDNF and PSD development are contradictory [16]. Among seven studies investigating the association between BDNF and the pathogenesis of PSD, five confirmed a significant association between them, but two studies could not.…”

“…Among seven studies investigating the association between BDNF and the pathogenesis of PSD, five confirmed a significant association between them, but two studies could not. Additionally, even the five studies that confirmed the association observed the association only in the early stage of stroke in most cases [16]. From the psychological and social perspectives, depression occurs due to physical discomfort and maladaptation to it [17,18], and the patient's sex is also associated with the development of PSD [19].…”

“…Thus, the possibility of early intervention to alleviate depression is less likely. The cumulative proportion of patients with PSD within five years from the onset of stroke is 39-52% [16].…”

Elevated Serum Cortisol Levels in Patients with Focal Epilepsy, Depression, and Comorbid Epilepsy and Depression

“…BDNF and cortisol are believed to be biomarkers of MDD [ 34 , 62 ], in particular, serum cortisol and mature BDNF are among the specific biomarkers with a potential on the evaluation of MDD chronicity [ 63 ]. Current research has identified associations between changes in serum BDNF levels and post-stroke depression [ 64 ]. In our study, serum BDNF was reduces in both groups with epilepsy, PWE, and PWCED; in the PWMDD group, the decrease showed a statistically significant trend, the mean value being similar to that of two groups with epilepsy.…”