Evening and morning plasma levels of protein S100B in patients with obstructive sleep apnea

Responsible for sleep brain perfusion changes, obstructive sleep apnea (OSA) constitutes a cardiovascular risk. To find out about any diffuse damage to the brain tissue, we studied the S100B protein, whose serum level is known to rise in stroke and craniocerebral trauma.

60 men (mean age 51.7+/-11.8 years) referred to us for OSA without any major comorbidity were examined polygraphically. S100B was determined with electrochemiluminiscence immunoassay (ECLIA) from evening and morning blood samples.

All sixty men were diagnosed with OSA. The difference between the evening level of S100B 0.068+/-0.030 microg/l and the morning level 0.059+/-0.029 microg/l was significant (p=0.0004). Patients with mild OSA were found to have the evening S100B 0.063+/-0.023 microg/l, the morning level 0.042+/-0.012 microg/l, the difference being significant (p=0.00051). In moderate OSA the difference between the evening -0.070+/-0.017 microg/l and morning levels -0.055+/-0.025 microg/l was less significant (p=0.043). In severe OSA no difference was found between the evening and morning concentrations of S100B (0.070+/-0.036 microg/l and 0.070+/-0.031 microg/l respectively). The difference between the evening and morning S100B levels correlated negatively with AHI and ODI and positively with basal saturation and average minimal oxygen saturation.

Sleep with signs of severe OSA influences S100B protein release.