Syntaxin-1a and SNAP-25 Expression Level is Increased in the Blood Samples of Ischemic Stroke Patients.

The interest in peripheral blood biomarkers is growing exponentially in several neurological disorders including Ischemic Stroke (IS). The identification of neurological biochemical signs through blood sample analyses would be revolutionary allowing a better pathology diagnosis giving also information on potential recovery after specific treatments. Indeed, the increased permeability of the blood-brain barrier, following a brain infarct, allows the detection of synaptic proteins in the blood flow. In this work, we analyzed the expression levels of two synaptic proteins belonging to the Soluble N-ethylmaleimide-Sensitive Fusion Protein Attachment Protein Receptor (SNARE) family, Syntaxin (STX)-1a and Synaptosomal Associated Protein, 25 kDa (SNAP-25), in Peripheral Blood Mononuclear Cell (PBMC), serum and in Neuronal Derived Extracellular vesicles (NDEs) of IS patients, age and sex matched healthy control (HC) and younger HC (Y-HC). Interestingly, we found, for the first time, that STX-1a protein is present in the cytoplasm of PBMC. Moreover, both protein, STX-1a and SNAP-25, levels were significantly augmented in all IS patient’s blood fractions (serum, PBMCs and NDEs) compared to control subjects. Interestingly, the STX-1a blood levels always correlated with the IS clinical scales National Institutes of Health Stroke Scale (NIH-SS) and the modified Barthel Index (BI). These results prompted us to speculate that STX-1a and SNAP-25 hematic fluctuations depict the brain damage after an ischemic attack and that their hematic detection could represent a novel and accessible IS biomarkers.