Cerebral and Extracranial Neurodegeneration are Strongly Coupled in Parkinson's Disease

In idiopathic Parkinson's disease (PD), a generalized Lewy body type-degeneration in the brain as well as extracranial organs was identified. It is unclear, whether cerebral and extracranial Lewy body type-degeneration in PD are coupled or not. To address this question, cerebral [(123)I]FP-CIT SPECT - to quantify cerebral nigrostriatal dopaminergic degeneration - and myocardial [(123)I]MIBG scintigraphy - to quantify extracranial myocardial sympathetic degeneration - were performed in 95 PD patients and 20 healthy controls. At each Hoehn and Yahr stage separately, myocardial MIBG uptake correlated significantly with striatal FP-CIT uptake. No such correlation was found in the controls. Cerebral and extracranial Lewy body type-degeneration in PD do not develop independently from each other but develop in a strongly coupled manner. Obviously cerebral and extracranial changes are driven by at least similar pathomechanisms. Our findings in controls contradict a physiological correlation between nigrostriatal dopaminergic and myocardial sympathetic function.