DPA714 PET Imaging Shows That Inflammation of the Choroid Plexus Is Active in Chronic-Phase Intracerebral Hemorrhage

Purpose : Our aims were to investigate the presence of choroid plexus (CP) inflammation in chronic-phase intracerebral hemorrhage (ICH) patients and to characterize any inflammatory cells in the CP.Patients and Methods : An in vivo F-18-DPA714 PET study was undertaken in 22 chronic-phase ICH patients who were admitted to the First Affiliated Hospital of Fujian Medical University or Tianjin Medical University General Hospital from April 2017 to June 2020. Ten control participants with nonhemorrhagic central nervous system diseases were included. Choroid plexus F-18-DPA714 uptake was calculated as the average SUVR. To aid the interpretation of the F-18-DPA714 uptake results at the CP level, Cy5-DPA714 in vivo imaging and immunofluorescence staining were used to show the presence of CP inflammation in an ICH mouse model during the chronic phase (14 weeks after ICH). Then immunofluorescence staining against translocator protein and other specific biomarkers was used to characterize the cells present in the inflamed CP of ICH mice in the chronic phase.Results: PET imaging showed that CP DPA714 SUVRs in chronic-phase ICH patients were higher than in controls (mean CP SUVR +/- SD; ICH group: 1.05 +/- 0.35; control group: 0.81 +/- 0.21; P = 0.006). Immunofluorescence staining of the CP in ICH model mice identified a population of CD45(+) immune cells, peripheral monocyte-derived CD14(+) cells, CD68(+) phagocytes, and CD11b(+) resident microglia/macrophages expressing translocator protein, possibly contributing to the increased F-18-DPA714 uptake.Conclusions: Our study shows that CP DPA714 uptake in chronic-phase ICH patients was higher than that of participants with nonhemorrhagic central nervous system diseases, which means that CP inflammation is still active in chronic-phase ICH patients.