Signs of Chronic Hypoxia Suggest a Novel Pathophysiological Event in α-Synucleinopathies.

BACKGROUND Multiple system atrophy (MSA) and Parkinson's disease (PD) patients develop respiratory and cardiovascular disturbances including obstructive sleep apnea, orthostatic hypotension, and nocturnal stridor. We hypothesized that, associated with these respiratory and cardiovascular disturbances, hypoxic events may occur in MSA and PD brains that may play a role in disease progression. The objective of this study was to evaluate the presence of hypoxia in nonneurological controls and PD and MSA patients. METHODS Molecular levels of hypoxia markers were measured in postmortem brain tissue from controls and PD and MSA cases. RESULTS MSA brain showed signs of chronic hypoxia characterized by the significant accumulation of the hypoxic marker HIF2α as compared to PD patients and controls. We detected no differences between MSA subtypes. Signs of hypoxia were also observed in PD patients with a clinical presentation similar to the MSA cases. CONCLUSIONS The results obtained from this study suggest a new alternative pathway associated with α-synucleinopathies that may contribute to the pathogenesis of these disorders. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC. on behalf of International Parkinson and Movement Disorder Society.