Serial brain FDG-PET and IMZ-SPECT following intracerebral MSC transplantation in patients with subacute ischemic stroke

Ischemic stroke is a leading cause of mortality and long-term neurological disability worldwide, and cell-based therapies represent a promising approach. Although clinical studies have reported favorable outcomes following cell transplantation, the effects on host neuronal integrity remain incompletely understood. This study investigated temporal and spatial changes in fluorodeoxyglucose positron emission tomography (FDG-PET) and 123I-iomazenil single-photon emission computed tomography (IMZ-SPECT) after intracerebral cell transplantation in patients with subacute ischemic stroke and examined their relationship with functional recovery. Seven adults with severe post-stroke disability underwent autologous mesenchymal stromal cell (HUNS001-01) transplantation 47-64 days after stroke onset. Brain FDG-PET and IMZ-SPECT were performed preoperatively and at 1, 3, and 12 months post-transplantation. Regions of interest were first manually set in the ipsilateral cortex where the 12-month postoperative-to-preoperative standard uptake value ratio seems increased, and followed by quantitative measurement. Five of seven patients demonstrated 5% or more increase of FDG-PET and/or IMZ-SPECT uptake in peri-infarct cortical regions, predominantly within the frontal or temporal cortex. Transplanted cells localized either within metabolically enhanced regions or in anatomically remote areas. FDG-PET and IMZ-SPECT changes were strongly interacted in each other and were associated with functional improvement. Overall, improvement of glucose metabolism and synaptic density/viability were observed in patient with subacute ischemic stroke, which may have been attributable to cell transplantation.Trial registration: UMIN000026130.