Cell Therapy for Ischemic Stroke with Nanoparticle-Labeled 293T Cells and Bone Marrow-Derived Mesenchymal Stem Cells: A Feasibility Study.

Background/Objectives: Stroke remains the second leading cause of death worldwide, and cell therapy is among the most actively investigated strategies for its treatment. Recent transcriptomic evidence has revealed that 293T cells-the most widely used transient transfection model-possess a neural crest/neuronal lineage, making them a candidate for acute neural tissue engineering. Methods: We implanted iron oxide nanoparticle-labeled 293T cells (293T-ION) into an ischemic rat brain and monitored them longitudinally by 7T MRI, using ION-labeled bone marrow-derived mesenchymal stem cells (rMSC-ION) as a direct comparison. Functional recovery was assessed via mNSS and corner test scores, and infarct size was quantified by MRI. Results: 293T-ION cells showed no migration throughout the 40-day observation period, and functional recovery plateaued early compared with the progressive improvement seen with rMSC-ION. 293T cell implantation provoked pronounced, localized CD68-positive microglial hyperactivation at both implantation and ischemic sites, without migration toward the choroid plexus (CP). In contrast, rMSC-ION actively migrated to the CP and drove superior neuroplasticity marker expression (Ki67, Nestin, NeuN). Conclusions: 293T cells produce transient localized microglial activation and limited brain plasticity, whereas rMSCs drive sustained neurorestoration. Synergistic co-administration of these cell types may represent a future therapeutic strategy bridging hyper-acute and chronic recovery phases.