Sex differences in cerebral energy metabolism in Parkinson's disease: A phosphorus magnetic resonance spectroscopic imaging study

Objective: To test the hypothesis that there are sex differences in cerebral energy metabolism in Parkinson's disease (PD). Methods: Phosphorus magnetic resonance spectroscopy (³¹P MRS) was used to determine high-energy phosphate (phosphocreatine and ATP) and low-energy phosphate (free phosphate) levels in the striatum and temporoparietal cortical gray matter (GM) in 10 men and 10 women with PD, matched for age at onset, disease duration, and UPDRS scores. Results: In the hemisphere more affected by PD, both ATP and high energy phosphate (HEP: phosphocreatine+ATP) content in striatum was 15% lower in men versus women with PD (p=.050 and p=.048, respectively). Similar decreases by 16% in ATP (p=.023) and 12% in HEP (p=.046) were observed in GM in men versus women with PD. In contrast, there were no detectable sex differences in ATP or HEP in healthy age-matched controls. Conclusions: Men with PD have lower levels of ATP and high energy phosphate than women in brain regions affected by PD. These findings suggest that there may be a greater burden of mitochondrial dysfunction in PD in men versus women with PD.