Extended AmplificationIn Vitroand Replicative Senescence: Key Factors Implicated in the Success of Human Myoblast Transplantation

Abstract

The limited success of human myoblast transplantation has been related to immune rejection, poor survival, and limited spread of injected myoblasts after transplantation. An important issue that has received little attention, but is nevertheless of fundamental importance in myoblast transplantation protocols, is the proliferative capacity of human satellite cells. Previous studies from our laboratory have demonstrated that the maximum number of divisions that a population of satellite cells can make decreases with age during the first two decades of life then stabilizes in adulthood. These observations indicate that when satellite cells are used as vectors in myoblast transplantation protocols it is important to consider donor age and the number of divisions that the cells have made prior to transplantation as limiting factors in obtaining an optimal number of donor derived muscle fibers. In this study, myoblasts derived from donors of different ages (newborn, 17 years old, and 71 years old) were isolated and amplified in culture. Their potential to participate in in vivo muscle regeneration in RAG2(-/-)/gamma(c)/C5 triple immunodeficient hosts after implantation was evaluated at 4 and 8 weeks postimplantation. Our results demonstrate that prolonged amplification in culture and the approach to replicative senescence are both important factors that may condition the success of myoblast transplantation protocols.

In Vivo Myogenic Potential of Human CD133+ Muscle-derived Stem Cells: A Quantitative Study

“…The number of human fiber profiles is higher than that obtained with bona fide human satellite cells presenting already a high regenerative capacity. 42 However, these satellite cells were isolated from a very young donor and have been extensively expanded after their isolation. Therefore, we also assessed the regenerative potential of CD133 + cells as compared to satellite cells freshly isolated from a 15-year-old donor, which would match the age range of the CD133 + cell donors: the regenerative potential of the 15-year-old donor primary culture was even lower than that of the control satellite cells isolated from the 5-day-old infant muscle, and therefore much lower than that of CD133 + cells.…”

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.…”

The satellite cell as a companion in skeletal muscle plasticity:currency, conveyance, clue, connector and colander

“…In muscular dystrophies, one concern about therapies that may increase muscle cell proliferation is that the replicative potential of satellite cells will become exhausted. Telomere shortening occurs on chromosomes as cells undergo numerous proliferative events, notable in DMD cells in culture (Cooper et al, 2003;Renault et al, 2002;Thornell et al, 2003), and it is well-established by modeling in cultures of muscle cells (derived from satellite cells) and single muscle fibres, that a gradual loss of proliferative capacity occurs with age and muscular dystrophy (Bockhold et al, 1998;Cooper et al, 2003;Jejurikar and Kuzon, Jr, 2003;Lagord et al, 1998;Renault et al, 2002). This 'bankruptcy' was demonstrated in vivo by experiments using repetitive muscle damage protocols that approached 50 events, exhausting the ability of satellite cells to proliferate and regenerate new muscle (Luz et al, 2002).…”