Optimizing Techniques for Tracking Transplanted Stem Cells In Vivo

Authors

  • Timothy R. Brazelton,

    1. Baxter Laboratory in Genetic Pharmacology, Department of Microbiology and Immunology and Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, California, USA
    2. Department of Surgery, The Children's Hospital of Philadelphia, The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
    Search for more papers by this author
  • Helen M. Blau Ph.D.

    Corresponding author
    1. Baxter Laboratory in Genetic Pharmacology, Department of Microbiology and Immunology and Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, California, USA
    • Stanford University School of Medicine, 269 W. Campus Drive, Stanford, California 94305-5175, USA. Telephone: 650-723-6209; Fax: 650-736-0080
    Search for more papers by this author

Abstract

The potential for bone marrow–derived cells (BMDCs) to contribute to nonhematopoietic tissues has generated considerable debate in recent years. Causes for the controversies include disparities in the techniques used to track engraftment of BMDCs, inappropriate tissue preparation, a lack of appropriate positive and negative controls, and basic misunderstandings about how to properly collect and interpret images from epifluorescent and confocal microscopes. Our laboratory was among the first to use bone marrow transplants from transgenic mice constitutively expressing enhanced green fluorescent protein (GFP) to study the ability of BMDCs to give rise to nonhematopoietic tissue types, a system that is now in widespread use. During our 6 years of experience using GFP, as well as beta-galactosidase and the Y chromosome, to track BMDCs in vivo, we have identified many difficulties and have developed techniques to resolve them. We discuss several of these methods, and, in particular, we describe ratiometric analysis techniques for improving detection of transplanted cells derived from genetically modified bone marrow. Finally, to help resolve reported discrepancies regarding the frequency with which BMDCs contribute to skeletal myofibers, we demonstrate that the pattern of highly autofluorescent myofibers in skeletal muscle is clearly distinct from that of GFP-expressing myofibers and describe how unambiguous conclusions can be drawn from such data.

Ancillary