In vivo analysis of neuroinflammation in the late chronic phase after experimental XXXX .

@entity1 @entity32 @entity19943 @entity64 @entity2806 @entity63 @entity2500 @entity39 @entity469 @entity11654 @entity22577 @entity35 @entity9212 @entity130
BACKGROUND AND PURPOSE: In vivo imaging of inflammatory processes is a valuable tool in @entity64 research. We here investigated the combination of two imaging modalities in the chronic phase after @entity2806 : magnetic resonance imaging (MRI) using intravenously applied ultra small supraparamagnetic iron oxide particles (USPIO), and positron emission tomography (PET) with the tracer [(11)C] @entity19943 . METHODS: @entity35 were subjected to permanent @entity2500 (pMCAO) by the macrosphere model and monitored by MRI and PET for 28 or 56days, followed by immunohistochemical endpoint analysis. To our knowledge, this is the first study providing USPIO-MRI data in the chronic phase up to 8weeks after @entity64 . RESULTS: Phagocytes with internalized USPIOs induced @entity9212 (   ) signal alterations in the brain. Combined analysis with [(11)C] @entity19943 -PET allowed quantification of phagocytic activity and other neuroinflammatory processes. From 4weeks after induction of @entity63 , @entity32 was dominated by phagocytes. Immunohistochemistry revealed colocalization of @entity11654 + microglia with [(11)C] @entity19943 and @entity22577 / @entity469 with USPIOs. USPIO-related iron was distinguished from alternatively deposited iron by assessing MRI before and after USPIO application. Tissue affected by non-phagocytic @entity32 during the first week mostly remained in a viably vital but remodeled state after 4 or 8weeks, while phagocytic activity was associated with @entity130 and @entity39 accordingly. CONCLUSIONS: We conclude that the combined approach of USPIO-MRI and [(11)C] @entity19943 -PET allows to observe post- @entity64 inflammatory processes in the living animal in an intraindividual and longitudinal fashion, predicting long-term tissue fate. The non-invasive imaging methods do not affect the immune system and have been applied to @entity1 subjects before. Translation into clinical applications is therefore feasible.
