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  • In vivo human molecular neu...
    Sala, Arianna; Caminiti, Silvia Paola; Presotto, Luca; Pilotto, Andrea; Liguori, Claudio; Chiaravalloti, Agostino; Garibotto, Valentina; Frisoni, Giovanni Battista; D'Amelio, Marcello; Paghera, Barbara; Schillaci, Orazio; Mercuri, Nicola; Padovani, Alessandro; Perani, Daniela

    Alzheimer's research & therapy, 11/2021, Letnik: 13, Številka: 1
    Journal Article, Web Resource

    Background Preclinical and pathology evidence suggests an involvement of brain dopamine (DA) circuitry in Alzheimer's disease (AD). We in vivo investigated if, when, and in which target regions 123IFP-CIT-SPECT regional binding and molecular connectivity are damaged along the AD course. Methods We retrospectively selected 16 amyloid-positive subjects with mild cognitive impairment due to AD (AD-MCI), 22 amyloid-positive patients with probable AD dementia (AD-D), and 74 healthy controls, all with available 123IFP-CIT-SPECT imaging. We tested whether nigrostriatal vs. mesocorticolimbic dopaminergic targets present binding potential loss, via MANCOVA, and alterations in molecular connectivity, via partial correlation analysis. Results were deemed significant at p < 0.05, after Bonferroni correction for multiple comparisons. Results We found significant reductions of 123IFP-CIT binding in both AD-MCI and AD-D compared to controls. Binding reductions were prominent in the major targets of the ventrotegmental-mesocorticolimbic pathway, namely the ventral striatum and the hippocampus, in both clinical groups, and in the cingulate gyrus, in patients with dementia only. Within the nigrostriatal projections, only the dorsal caudate nucleus showed reduced 123IFP-CIT binding, in both groups. Molecular connectivity assessment revealed a widespread loss of inter-connections among subcortical and cortical targets of the mesocorticolimbic network only (poor overlap with the control group as expressed by a Dice coefficient less than or equai to 0.25) and no alterations of the nigrostriatal network (high overlap with controls, Dice coefficient = 1). Conclusion Local- and system-level alterations of the mesocorticolimbic dopaminergic circuitry characterize AD, already in prodromal disease phases. These results might foster new therapeutic strategies for AD. The clinical correlates of these findings deserve to be carefully considered within the emergence of both neuropsychiatric symptoms and cognitive deficits. Keywords: Biomarker, Dopamine, Molecular connectivity, Substantia nigra, Ventral tegmental area