RESUMO
Oxysterols are important for cholesterol homeostasis in the brain and may be affected in neurodegenerative diseases. The levels of the brain-derived oxysterol 24S-hydroxycholesterol (24S-OH) have been reported to be markedly reduced in the circulation of patients with Parkinson's disease (PD) (Lee et al., Antioxid. Redox Signal. 11 (2009) 407-420). The finding is surprising in view of the fact that other neurodegenerative diseases are associated with relatively modest effects on the circulating levels of 24S-OH. We determined the plasma and cerebrospinal fluid (CSF) levels of 24S-OH and 27-hydroxycholesterol (27-OH) in patients with PD with different disease duration using a highly accurate method based on isotope dilution-mass spectrometry. All the patients had plasma levels of the different oxysterols within the normal range. When analyzing CSF, 10% of the PD patients were found to have levels of 24S-OH above the cut-off level and interestingly there was a significant correlation between levels of 24S-OH in CSF and duration of the disease (r=0.40, P<0.05). The CSF level of 27-OH was found to be above the cut-off level in 10% of the patients, indicating a defect blood-brain barrier function. There was no correlation between levels of 27-OH in CSF and duration of the disease. These data indicates that oxysterol levels in CSF may be of value to follow disease progression.