Acute Ischemic Stroke Diagnostic Biomarkers: Brain-Derived Neurotrophic Factor (BDNF) and Its Correlation with Lipid Profiles in Acute Ischemic Stroke Patients

Background: Brain-derived neurotrophic factor (BDNF) interacts with tropomyosin-related kinase B (TrkB) to promote neuronal growth, survival, differentiation, neurotransmitter release, and synaptic plasticity. Elevated levels of BDNF in the central nervous system and blood are linked with several neurodegenerative diseases.
Study Aim: The research aims to understand whether BDNF levels correlate with lipid profile changes in AIS and to assess BDNF's potential as a diagnostic biomarker for AIS.
Methods: The study involved two parts.
The first part assessed the correlation between plasma BDNF levels and lipid profiles, including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C), in 90 AIS patients at the stroke center between July 2014 to September 2019. Patients qualified for the study if they had no history of psychiatric or neurological disorders and were experiencing their first-ever AIS, as diagnosed by a neurologist. Data was collected from their medical records, standardized structured questionnaire interviews, and brain imaging. A logistic regression analysis was conducted to assess the relationship between BDNF and lipid profiles, utilizing odds ratios and 95% confidence intervals. The categorization of higher and lower BDNF levels was based on the median value of 3.227 ng/ml. BDNF levels were measured using an enzyme-linked immunosorbent assay.
The second part evaluated the diagnostic accuracy of plasma BDNF levels in distinguishing new-onset AIS patients from individuals without AIS. A total of 90 AIS patients (61% male, with a mean age of 67.7 ± 12.88) were recruited consecutively in a stroke unit, and each patient was paired with two age- and gender-matched controls. A receiver operating characteristic curve (ROC) analysis and an area under the ROC curve (AUC) analysis were applied. Sensitivity and a function of 1-specificity were used to measure the accuracy of BDNF for discriminating AIS patients from the normal controls.
Results:
In the first part, the study found that the high BDNF group (≥3.227ng/ml) had significantly higher levels of Hemoglobin A1C, TG, the ratios of TC/HDL-C, LDL-C/HDL-C, and TG/HDL-C, and a higher percentage of hyperlipidemia (60%), as well as a lower level of HDL-C. We found a significant correlation between elevated plasma BDNF levels and lipid profiles in AIS patients. The OR for TG/HDL-C was 1.903 (95% CI: 1.187-3.051), for TC/HDL-C was 1.975 (95% CI: 1.188-3.284), and for LDL-C/HDL-C was 2.032 (95% CI: 1.113-3.711).
In the second part, the study found that individuals with AIS patients exhibited significantly higher levels of BDNF, blood pressure, Hemoglobin A1c, white blood cells, and creatinine levels compared to a control group. The plasma levels of BDNF can significantly discriminate AIS patients from healthy individuals (AUC 0.76), with sensitivity and specificity of 73% and 73.3% respectively.
Conclusion: BDNF may play a role in lipid metabolism and serve as an indicator of lipid profile status in AIS patients. It also has potential as a biomarker for AIS risk stratification and early diagnosis. The findings suggest the need for further research to explore the clinical utility of BDNF in stroke-related healthcare.