Serum Sphingosine 1-Phosphate (S1P): A Novel Diagnostic Biomarker in Early Acute Ischemic Stroke

Background: Sphingosine 1-phosphate (S1P) is a lipid metabolite that mediates various physiological processes, including vascular endothelial cell function, inflammation, coagulation/thrombosis, and angiogenesis. As a result, S1P may contribute to the pathogenesis of stroke. Objective: This study aimed to evaluate the diagnostic value of serum S1P in acute stroke. Method: A total of 72 patients with ischemic stroke, 36 patients with hemorrhagic stroke, and 65 controls were enrolled. Serum S1P was detected by enzyme-linked immunosorbent assay (ELISA). Results: Receiver operating characteristic curve analysis demonstrated that serum S1P could discriminate ischemic stroke from hemorrhagic stroke in both total population and subgroup analyses of samples obtained within 24 h of symptom onset (subgroup _{< 24h}) (area under curve, AUC_Total = 0.64, P = 0.017; AUC_{Subgroup < 24h} = 0.91, P < 0.001) and controls (AUC_Total = 0.62, P = 0.013; AUC_{Subgroup <24h} = 0.83, P < 0.001). Furthermore, S1P showed higher efficacy than high-density lipoprotein cholesterol (HDL-C) in discriminating ischemic stroke from controls in the total population (P _S1P = 0.013, P _HDL-C = 0.366) and in the subgroup analysis (i.e., <24 h; P _S1P < 0.001, P _HDL-C = 0.081). Additionally, lower serum S1P was associated with cervical artery plaques (P = 0.021) in controls and with dyslipidemia (P = 0.036) and milder neurological impairment evaluated by the National Institute of Health Stroke Scale (NIHSS, P = 0.047) in the ischemic stroke group. Conclusions: The present study preliminarily investigated the diagnostic value of serum S1P in acute stroke. Decreased serum S1P may become a potential biomarker for early acute ischemic stroke and can indicate disease severity.