Elevation in circulating YKL-40 concentration in patients with cerebrovascular disease

YKL-40 is a novel inflammatory protein. Elevated serum levels of YKL-40 have been reported in patients with atherosclerosis and other cardiovascular diseases, but the circulating profile of YKL-40 in patients with cerebrovascular disease has been less investigated. This prospective observational study aimed to determine serum levels of YKL-40 in patients with different subtypes and severities of cerebrovascular disease. Eighty patients with acute ischemic stroke, 30 patients with acute hemorrhagic stroke, 15 patients with transient ischemic attack (TIA) and 18 age- and gender-matched healthy control subjects were recruited. Blood was sampled. Serum levels of YKL-40 were measured by ELISA. In healthy control subjects, serum levels of YKL-40 were 43.09 +/- 31.41 ng/ml, significantly lower than those in patients with acute ischemic stroke (178.58 +/- 127.78 ng/ml), hemorrhagic stroke (105.32 +/- 87.35 ng/ml) and TIA (148.09 +/- 108 ng/ml) respectively (p<0.05). When the 80 acute ischemic stroke cases were stratified into four Oxfordshire Community Stroke subtypes, serum levels of YKL-40 were significantly higher in patients with total anterior (n=16), partial anterior (n=25) and posterior (n=12) circulation infarctions respectively than in those with lacunar (n=27) infarction (p<0.05). Moreover, 63 of 80 patients with acute ischemic stroke survived. Circulating levels of YKL-40 in these stroke survivors were associated with the United States National Institutes of Health Stroke Scale (NIHSS) scores of neurological deficit. In summary, serum levels of YKL-40 were elevated in patients with cerebrovascular disease in lesion subtype- and severity-dependent manners. These observations suggest a potential for YKL-40 as a diagnostic/prognostic biomarker for cerebrovascular disease.