Two distinct degenerative types of nigrostriatal dopaminergic neuron in the early stage of parkinsonian disorders

Tomoya Kawazoe; Keizo Sugaya; Yasuhiro Nakata; Masato Okitsu; Kazushi Takahashi

doi:10.1016/j.prdoa.2024.100242

Two distinct degenerative types of nigrostriatal dopaminergic neuron in the early stage of parkinsonian disorders

Clin Park Relat Disord. 2024 Feb 15:10:100242. doi: 10.1016/j.prdoa.2024.100242. eCollection 2024.

Authors

Tomoya Kawazoe¹, Keizo Sugaya¹, Yasuhiro Nakata², Masato Okitsu¹, Kazushi Takahashi¹

Affiliations

¹ Department of Neurology, Tokyo Metropolitan Neurological Hospital (TMNH), Tokyo, Japan.
² Department of Neuroradiology, TMNH, Tokyo, Japan.

Abstract

Introduction: The present study characterized the degeneration of nigrostriatal dopaminergic neurons in the early stages of parkinsonian disorders using integrative neuroimaging analysis with neuromelanin-sensitive MRI and ¹²³I-FP-CIT dopamine transporter (DAT) SPECT.

Methods: Thirty-one, 30, and 29 patients with progressive supranuclear palsy (PSP), corticobasal syndrome (CBS) with abnormal specific binding ratio (SBR) in either hemisphere (mean ± 2SD), and parkinsonism-predominant multiple system atrophy (MSA-P), respectively, were enrolled. Neuromelanin-related contrast (NRC) in the substantia nigra (NRC_SN) and locus coeruleus (NRC_LC) and the SBR of DAT SPECT were measured. All the patients underwent both examinations simultaneously within five years after symptom onset. After adjusting for interhemispheric asymmetry on neuromelanin-related MRI contrast using the Z-score, linear regression analysis of the NRC_SN and SBR was performed for the most- and least-affected hemispheres, as defined by the interhemispheric differences per variable (SBR, NRC_SN, standardized [SBR + NRC_SN]) in each patient.

Results: Although the variables did not differ significantly between PSP and CBS, a significant correlation was found for CBS in the most-affected hemisphere for all the definitions, including the clinically defined, most-affected hemisphere. No significant correlation was found between the NRC_SN and SBR for any of the definitions in either PSP or MSA-P.

Conclusion: Together with the findings of our previous study of dementia with Lewy bodies (DLB) and Parkinson's disease (PD), the present findings indicated that neural degeneration in the disorders examined may be categorized by the significance of the NRC_SN-SBR correlation in PD and CBS and its non-significance in DLB, PSP, and MSA-P.

Keywords: Corticobasal degeneration; Dopamine transporter SPECT; Multiple system atrophy; Neuromelanin-sensitive MRI; Nigrostriatal dopaminergic degeneration; Progressive supranuclear palsy.