Dynamic tracking of human umbilical cord mesenchymal stem cells (hUC-MSCs) following intravenous administration in mice model

In the past decades, human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) have sparked interest in cellular therapy due to their immunomodulatory properties. Nevertheless, the fate of hUC-MSCs in the body remains poorly understood. This study aimed to investigate the biodistribution, homing and clearance of systemically administered hUC-MSCs in healthy BALB/c mice model. hUC-MSCs were labelled with GFP-Luc2 protein, followed by characterisation with flow cytometry. Upon intravenous infusion of transduced hUC-MSCs into the healthy BALB/c mice, the cells were dynamically monitored through the bioluminescent imaging (BLI) approach. Transduction of hUC-MSCs with GFP-Luc2 not only preserved the characteristics of MSCs, but also allowed live monitoring of transduced cells in the mice model. Upon systemic administration, BLI showed that transduced hUC-MSCs first localised predominantly in the lungs of healthy BALB/c mice and mainly remained in the lungs for up to 3 days before eventually cleared from the body. At terminal sacrifice, plasma chemistry biomarkers remained unchanged except for C-peptide levels, which were significantly reduced in the hUC-MSCs group. Histopathological findings further revealed that hUC-MSCs infusion did not cause any adverse effects and toxicity to lung, liver and heart tissues. Collectively, systemically administrated hUC-MSCs was safe and demonstrated dynamic homing capacity before eventually disappearing from the body. •GFP-Luc2-lentiviral transduction did not alter hUC-MSCs basic characteristics.•GFP-Luc2-transduced hUC-MSCs allowed dynamic monitoring in mice model.•HUC-MSCs mainly localised in the lungs up to 3 days before cleared from the body.•Intravenously infused hUC-MSCs did not cause any adverse events or toxicity in mice.