Cerebrospinal Fluid Free Fatty Acid Levels Are Associated with Stroke Subtypes and Severity in Chinese Patients with Acute Ischemic Stroke.

OBJECTIVE: To assess the clinical significance of cerebrospinal fluid (CSF) free fatty acid (FFA) levels in Chinese patients with acute ischemic stroke. METHODS: From December 2011 to October 2014, all patients with first-ever acute ischemic stroke were recruited to participate in the study. CSF levels of FFAs were assayed at 4 time points, and severity of stroke was evaluated with the National Institutes of Health Stroke Scale (NIHSS) score on admission. RESULTS: Median CSF FFA levels were significantly (P < 0.0001) higher in patients with stroke compared with control subjects. CSF FFA levels reflected the disease severity of acute ischemic stroke. There were significant positive associations between CSF FFA levels and NIHSS scores (r = 0.424, P < 0.0001) and infarct volume (r = 0.289, P < 0.0001). CSF FFA levels in patients with cardioembolic (CE) stroke were significantly higher compared with patients with non-CE stroke (0.34 mmol/L [interquartile range, 0.26-0.42] vs. 0.14 mmol/L [interquartile range, 0.08-0.23]; P < 0.0001). Based on the receiver operating characteristic curve, the optimal cutoff value of CSF FFA levels as an indicator for the diagnosis of CE stroke was projected to be 0.22 mmol/L, which yielded a sensitivity of 83.3% and a specificity of 75.3%, and the area under the curve was 0.873 (95% confidence interval, 0.810-0.935). CONCLUSIONS: CSF FFA levels at the time of admission were associated with stroke severity and lesion volumes. In addition, CE stroke can be distinguished from other stroke etiologies by measuring CSF FFA levels very early.

Kynurenic acid in brain and cerebrospinal fluid of fetal, newborn, and adult sheep and effects of placental embolization.

Concentrations of the endogenous glutamate receptor antagonist kynurenic acid (KA) were measured in various brain regions and in cisternal cerebrospinal fluid of fetal, newborn, and adult sheep. KA concentrations were significantly higher in the fetal brain and cerebrospinal fluid at 90 and 140 d gestation compared with postnatal ages. In fetuses of 132-139 d gestation, KA concentrations in cerebrospinal fluid collected by drainage from an indwelling cisternal catheter increased significantly after infusion of the organic acid transport inhibitor probenecid (100 or 200 mg/kg, i.v.) indicating active transport of KA out of the fetal brain. In fetuses in which the umbilical circulation had been chronically restricted from 120 to 140 d gestation by partial embolization of the placenta, plasma concentrations of the KA precursor kynurenine were significantly lower than in control fetuses, and KA concentrations in the hypothalamus and hippocampus were significantly reduced; other brain regions were not affected. These results indicate that the production of KA is higher in the fetal brain compared with the newborn and adult brain. Because KA diminishes the risk of excitotoxic neuronal damage under hypoxic-ischemic conditions, the high levels of KA in the brain before birth may have a neuroprotective function. The decrease of KA concentrations in the hypothalamus and hippocampus after umbilical embolization suggests that, after chronic hypoxia in utero, these regions of the brain may become more vulnerable to subsequent episodes of acute hypoxia or ischemia encountered in late gestation or during parturition.