Level of S100B protein, neuron specific enolase, orexin A, adiponectin and insulin-like growth factor in serum of pediatric patients suffering from sleep disorders with or without epilepsy.

BACKGROUND Paroxysmal sleep disorders in children are important from both pathophysiological and clinical point of view. Correct diagnosis is crucial for further management. The aim of the present study was to identify peripheral markers of paroxysmal sleep disorders in children, which could improve diagnostics of these disorders. We compared serum levels of several putative biomarkers of neurological disorders, such as S100B protein, neuron specific enolase (NSE), orexin A, adiponectin, and insulin-like growth factor 1 (IGF-1) in pediatric patients suffering from sleep disturbances with those who additionally to parasomnia revealed also epilepsy. METHODS Fifty six children from 1 month to 18 years of age hospitalized in the Pediatric Neurology Clinic, Chair of Children and Adolescent Neurology, participated in this study. Polysomnographic diagnostics was indicated due to sleep disturbances. Examination was performed with the use of polysomnography and videoelectroencephalography Grass device. Blood samples were taken before registration of sleep, after 2.5 h of sleep or 0.5 h after occurrence of clinical seizures. Concentrations of S100B protein, NSE, orexin A, adiponectin, and IGF-1 were measured by specific ELISA methods. RESULTS The obtained data showed that serum S100B level was significantly increased in children with epilepsy and clinical seizure attacks as compared to patients with parasomnia only. Atendency to enhanced serum S100B level was also seen in epileptic children without clinical seizures during polysomnographic recording. The level of orexin A was significantly decreased in epileptic children without seizures as compared to the hormone level in parasomnic patients, but was elevated in patients who experienced seizures during polysomnographic examination. As S100B is regarded to be a marker of blood brain barrier leakage and astrocyte damage, the data suggest an increase in BBB permeability in epileptic children, especially during seizure fits. Furthermore, the enhanced S100B serum level without changes in NSE activity may be interpreted rather as an evidence of the elevated secretion of this protein during seizures than of the damage of brain tissue. In contrast to S100B and orexin A level, serum concentration of adiponectin and IGF-1 as well as NSE activity did not significantly differ between the studied groups. CONCLUSION Out of the five putative biomarkers measured, blood concentration of S100B and orexin A may be helpful in differentiating parasomnic pediatric patients with and without epilepsy.