Cardiac sympathetic impairment parallels nigrostriatal degeneration in Probable Dementia with Lewy Bodies
QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING
Authors: Camacho, V.; Marquie, M.; Lleo, A.; Alves, L.; Artigas, C.; Flotats, A.; Duch, J.; Blesa, R.; Gomez-Isla, T.; Carrio, I.; Estorch, M.
Abstract
Aim. Dementia with Lewy Bodies (DLB) must be distinguished from other types of dementia because of important differences in patient management and outcome. Both reduction in cardiac I-123-metaiodobenzilguanidine (MIBG) uptake and decreased I-123-FP-CIT binding in basal ganglia have been described in DLB. The aim of this study was to assess the relationship between cardiac sympathetic activity and nigrostriatal degeneration in patients with probable DLB. Methods. Twenty-eight patients (15 males; mean age 77 years, range 64-88 years) with clinical international criteria of probable DLB were included in the study. All patients underwent a cardiac MIBG scintigraphy and a FP-CIT SPECT. Global cardiac MIBG uptake was semiquantified by means of heart-to-mediastinum ratio (HMR) (normal >1.56). FP-CIT binding in basal ganglia was calculated and compared with an age-matched control group. The relation between cardiac MIBG uptake and FP-CIT uptake in basal ganglia, and the relationship of these two techniques with distinctive symptoms of DLB, features of past medical history and data from the neuropsychological examination were assessed. Results. Cardiac MIBG uptake was decreased in 23 of 28 patients (HMR=1.32, range 0.95-1.85). The FP-CIT binding in basal ganglia was significantly lower than in control group (2.01+/-0.5 vs 2.62+/-0.2, P<0.05). All patients with reduced cardiac HMR showed decreased FP-CIT binding in basal ganglia. There was a positive correlation between the HMR and specific binding ratio of striatum (P<0.01). A high correlation between FP-CIT SPECT and the presence of parkinsonism also was found. No correlation between cardiac MIBG uptake and demographic, clinical or neuropsychological data was found. Conclusions. In probable DLB cardiac MIBG uptake and FP-CIT binding in basal ganglia are reduced. The positive correlation between both measures suggests that cardiac sympathetic degeneration and nigrostriatal degeneration parallel similarly in patients with probable DLB.
Distinct beta-catenins mediate adhesion and signalling functions in C-elegans
NATURE
Authors: Korswagen, HC; Herman, MA; Clevers, HC
Abstract
In flies and vertebrates, Armadillo/beta-catenin forms a complex with Tcf/Lef-1 transcription factors, serving as an essential coactivator to mediate Wnt signalling. It also associates with cadherins to mediate adhesion. In Caenorhabditis elegans, three putative beta-catenin homologues have been identified: WRM-1, BAR-1 and HMP-2. WRM-1 and the Tcf homologue POP-1 mediate Wnt signalling by a mechanism that has challenged current views of the Wnt pathway(1-3). Here we show that BAR-1 is the only beta-catenin homologue that interacts directly with POP-1. BAR-1 mediates Wnt signalling by forming a BAR-1/POP-1 bipartite transcription factor that activates expression of Wnt target genes such as the Hox gene mab-5. HMP-2 is the only beta-catenin homologue that interacts with the single cadherin of C. elegans, HMR-1. We conclude that a canonical Wnt pathway exists in C. elegans. Furthermore, our analysis shows that the functions of C. elegans beta-catenins in adhesion and in signalling are performed by separate proteins.