Assessment of a nuclear affinity labeling method for tracking implanted mesenchymal stem cells.

Area of Science:

• Cardiovascular Research
• Stem Cell Biology
• Regenerative Medicine

Background:

• Mesenchymal stem cells (MSCs) show therapeutic potential but their fate after in vivo application is unclear.
• Varied cell labeling and administration methods contribute to discrepancies in MSC research.
• A reliable tracking method is needed for MSC myocardial implantation in large animal models.

Purpose of the Study:

• To evaluate different mesenchymal stem cell (MSC) labeling methods for tracking in a large animal cardiac model.
• To determine the viability, proliferation, differentiation potential, and gene expression of labeled MSCs.
• To assess the in vivo distribution and fate of MSCs after myocardial implantation.

Main Methods:

• Experimented with adenovirus-mediated enhanced green fluorescence protein (EGFP) and beta-galactosidase (LacZ) expression, and DAPI nuclear staining for MSC labeling.
• Administered labeled porcine MSCs via intramuscular and intracoronary routes in a large animal model.
• Utilized optimized live cell labeling for bright, nucleus-confined blue fluorescence and performed histological analysis.

Main Results:

• DAPI nuclear staining proved to be a reliable stem cell tracking marker for myocardial implantation.
• DAPI-labeled MSCs maintained viability, ceased proliferation, showed increased differentiation potential, and enhanced CXCR4/SDF1 expression.
• Approximately 2% of administered MSCs were localized in the heart 2 weeks post-coronary infusion, primarily in the interstitium, indicating migration across endothelium.

Conclusions:

• DAPI is a suitable and reliable marker for tracking mesenchymal stem cells (MSCs) in cardiac applications.
• Labeled MSCs retain essential biological functions, including migration and response to injury signals.
• Further research is needed to understand the long-term fate and therapeutic efficacy of MSCs in myocardial repair.