To determine the utility of 8,12-isoprostaneF2α-VI (iP), a specific and sensitive index of lipid peroxidation, as a biomarker for dementia in Parkinson disease (PD).Background
iP is a member of the F2-isoprostanes family that has been shown to be promising biomarker for Alzheimer disease. However, iP levels have not been studied in patients with clinical diagnosis of PD or Parkinson disease with dementia (PDD).Methods
PD and PDD patient plasma and urine iP levels were compared with age-matched and sex-matched controls. Clinical measures including demographics and tests of motor function, affect, and cognition were assessed and compared with iP levels.Results
There were no differences in plasma iP levels between PD subjects and controls (299 vs. 306 pg/mL; P=0.6). Urine iP levels were higher in cases than controls (2.8 vs. 2.1 ng/mg Cr; P=0.003), but levels were lower than those seen in Alzheimer disease patients in prior studies. Within PD subjects, there was no association of iP levels in either the plasma or urine with performance on any clinical measure.Conclusions
Plasma and urine iP levels do not seem to be substantially elevated in PD and are not associated with severity of cognitive impairment in PDD.