Circulating brain-derived neurotrophic factor as a potential biomarker in stroke: a systematic review and meta-analysis

Abstract

Background Stroke, an acute cerebrovascular event, is a leading cause of disability, placing a significant psycho-socioeconomic burden worldwide. The adaptation and reorganization process following any neuronal damage is regarded as neuroplasticity. Among many factors believed to attribute to this process, Brain-derived Neurotrophic Factor (BDNF) is a neurotrophin coordinating neuroplasticity after various neurological disorders such as stroke. Methods We conducted a systematic search in the main electronic medical databases in January 2021. Primarily we want to compare BDNF levels between patients with stroke and healthy controls (HC). Additional aims included investigation of (1) longitudinal changes in the BDNF levels post-stroke, (2) effects of physical training, (3) repeated transcranial magnetic stimulation (rTMS), and presence of depression on BDNF levels in patients with stroke. Results Among 6243 reviewed records from PubMed, Web of Science, and Scopus, 62 studies were eligible for inclusion in our systematic review. Subjects with stroke, n = 1856, showed lower BDNF levels compared to HC, n = 1191 (SMD [95%CI] = − 1.04 [− 1.49 to − 0.58]). No significant difference was detected in the level of BDNF through time points past stroke. BDNF levels were lower in the patients with depression compared to non-depressed subjects (SMD [95%CI] = − 0.60 [− 1.10 to − 0.10]). Physical training had an immediate positive effect on the BDNF levels and not statistically significant effect in the long term; SMD [95%CI] = 0.49 [0.09 to 0.88]) and SMD [95%CI] = 0.02 [− 0.43 to 0.47]). Lastly, rTMS showed no effect on the level of BDNF with 0.00 SMD. Conclusions Our study confirms that stroke significantly decreases the level of BDNF in various domains such as cognition, affect, and motor function. As BDNF is the major representative of neuroplasticity within nervous system, it is believed that stroke has a significant impact on the CNS regeneration, which is permanent if left untreated. This effect is intensified with coexisting conditions such as depression which further decrease the BDNF level but the net impact yet needs to be discovered. We also conclude that exercise and some interventions such as different medications could effectively reverse the damage but further studies are crucial to reach the exact modality and dosage for their optimal effect.

JNK pathway‐associated phosphatase in acute ischemic stroke patients: Its correlation with T helper cells, clinical properties, and recurrence risk

“… 5 , 6 In order to extend treatment application and improve AIS management, there is a need to find out novel biomarkers to assist identify early and monitoring of the prognosis of AIS patients. 7 , 8 , 9 …”

“…In addition, due to the narrow therapeutic time window that limits the therapeutic application, only a minority of AIS patients benefit from the timely effective AIS treatment methods 5,6 . In order to extend treatment application and improve AIS management, there is a need to find out novel biomarkers to assist identify early and monitoring of the prognosis of AIS patients 7–9 …”

Effect of Exercise on Brain-Derived Neurotrophic Factor in Stroke Survivors: A Systematic Review and Meta-Analysis

“…7 A meta-analysis demonstrated a program of aerobic exercise increased BDNF concentration, but only one study examined stroke survivors, and nonaerobic exercise interventions were excluded. 8 While another demonstrated acute effects of physical training on BDNF concentration, 9 it remains unclear how exercise training parameters (ie, intensity and mode) influence BDNF concentration poststroke. There is currently no systematic review demonstrating the effects of resistance training on BDNF concentration poststroke, and studies have produced variable results in healthy adults.…”

A meta-analysis on the role of brain-derived neurotrophic factor in Parkinson’s disease patients

“…[99][100][101][102][103] A previous meta-analysis similarly showed that BDNF had favorable advantages in treating PD and reducing PD with depression. [104][105][106][107][108][109][110] To determine whether age and ethnicity are connected to the outcomes of our study, well-conducted randomized controlled trials are needed.…”