Tracking adipose-derived mesenchymal stromal cells in the eye: Integrating IVIS imaging and Alu PCR for enhanced detection of human cells

Introduction: Cell transplantation finds broad applications in medical science, with applications ranging from stem cell therapies to cancer research. Despite its widespread use, inherent risks such as tumor formation and immune rejection necessitate a comprehensive understanding of transplanted cell dynamics. Thus, tracing cellular behavior is a critical aspect of medical research, particularly in the context of cell transplantation. The capacity to precisely monitor and evaluate the behavior of transplanted cells over time is essential for evaluating therapeutic effectiveness, safety profiles, and long-term consequences. Traditional imaging approaches, like Z-stack and overlay images, present challenges due to limitations in sample size, determining cell location and migration, and only observing the one moment of the therapeutical application. However, recent advancements in imaging technologies have significantly improved our ability to trace cellular behavior in vivo. Bioluminescence imaging (BLI) has emerged as a powerful tool for non-invasive, real-time monitoring of cell survival, proliferation, and distribution in animal models. The in vivo imaging system (IVIS) for instance, focuses on its non-invasive nature and versatile applications in real-time investigations. Genetically modified cells express luciferase, allowing for the detection of light emission when luciferin is administered. BLI offers high sensitivity and the ability to track cells over extended periods, providing crucial information about cell engraftment and persistence. Method: Transfecting human adipose mesenchymal stem cells (adMSCs) with a lentiviral vector encoding firefly luciferase under the CAG promoter (CAG-ffLuc-cp156), which allows to establish a comprehensive understanding of adMSC behavior, distribution, and therapeutic safety, addressing a critical obstacle in the clinical evaluation of stem cell applications. The study tracked transfected adMSCs over seven days, with subsequent analysis of human DNA distribution by Alu-PCR. Result: Data indicates adMSCs disappear from the recipient by day 7, corroborated by the absence of human DNA in tested organs. The primary objective is to present a methodology for subconjunctival delivery, investigating the biodistribution and migration of adMSCs post-injection, with potential implications for various cell therapies. Conclusion: This study provides a valuable methodology for investigating cell behavior post-injection, contributing to the optimization of cell therapies for clinical applications. Furthermore, it highlights the safety of applying adMSCs with relatively low potential of tumorgenicity.