Human Muscle Precursor Cell Regeneration in the Mouse Host Is Enhanced by Growth Factors

Abstract

The aim of this study was to optimize human muscle formation in vivo from implanted human muscle precursor cells. We transplanted donor muscle precursor cells (MPCs) prepared from postnatal or fetal human muscle into immunodeficient host mice and showed that irradiation of host muscle significantly enhanced muscle formation by donor cells. The amount of donor muscle formed in cryodamaged host muscle was increased by exposure of donor cells to growth factors before their implantation into injured host muscle. Insulin-like growth factor type I (IGF-I) significantly increased the amount of muscle formed by postnatal human muscle cells, but not by fetal human MPCs. However, treatment of fetal muscle cells with IGF-I, in combination with basic fibroblast growth factor and plasmin, significantly increased the amount of donor muscle formed. In vivo, human MPCs formed mosaic human-mouse muscle fibers, in which each human myonucleus was associated with a zone of human sarcolemmal protein spectrin.

Cell Transplantation and “Stem Cell Therapy” in the Treatment of Myopathies: Many Promises in Mice, Few Realities in Humans

“…We observed abundant human-derived satellite cells in mouse muscles one month after the transplantation of myoblasts cultured from adult humans [35] (Figure 4). These human-derived satellite cells explain the presence of donorderived muscle-precursor cells evidenced in experiments of culture and retransplantation in immunodeficient mice [35] and confirm preliminary observations suggesting that some human nuclei in isolated human/mouse hybrid myofibers were satellite cells [36]. Human fetal myoblasts also produced mononucleated muscle-precursor cells following transplantation in immunodeficient mice [37].…”

“…Another possibility (more accessible to laboratories that do not have access to irradiation equipment) is cryodamage. In this case, freezing the recipient muscles combines myofiber necrosis with killing the recipient's satellite cells, and it was used in mice as a pretreatment to increase the engraftment of the implanted myogenic cells [21,22,36,38].…”

Mouse Regenerating Myofibers Detected as False-Positive Donor Myofibers with Anti-Human Spectrin

“…Tibialis anterior muscles were cryoinjured, or irradiated with 18 Gy 3 days before cryoinjury and grafting as described previously (Brimah et al, 2004;Boldrin et al, 2012). Into some of these cryoinjured host muscles, either 1 · 10 6 donor human myoblasts, derived from a 2-year-old male patient with DMD, or 5 · 10 5 human skeletal muscle-derived CD133 + cells derived from the paraspinal muscle of a 16-year-old male with adolescent idiopathic scoliosis, or no cells, were grafted.…”

“…Human cells are routinely injected into immune-deficient mouse models of muscular dystrophy, such as the mdx4 cv and mdx5 cv models bred into the NSG or NOD/Rag1 null background (Darabi et al, 2012;Goudenege et al, 2012;; or into immunedeficient mice in which the recipient muscle has been damaged with cardiotoxin or by cryoinjury before injection (Cooper et al, 2001(Cooper et al, , 2003Brimah et al, 2004;Ehrhardt et al, 2007;Crisan et al, 2008;Negroni et al, 2009;Meng et al, 2010Meng et al, , 2011. After transplantation, the presence of engrafted human cells is detected via immunofluorescence staining using antibodies that recognize human, but not mouse, proteins.…”

Are Human and Mouse Satellite Cells Really the Same?

“…In vitro expansion of donor mouse (Montarras et al 2005) and chicken satellite cells (O'Neill and Stockdale 1972) for only a short time significantly reduces the number of muscle fibers they form in vivo, probably because they commence myogenic differentiation. Similar to mouse, the regenerative capacity of human mpc is reduced after they have been expanded in vitro (Cooper et al 2003;Brimah et al 2004), which may be as a result of senescence during the culture period (Decary et al 1996). This suggests that expansion of both mouse and human mpc in vitro may cause stem-like properties to be outweighed and therefore lost.…”