Sera from young and older humans equally sustain proliferation and differentiation of human myoblasts

Abstract

Please cite this article as: George, Tomasz, Velloso, Cristiana P., Alsharidah, Mansour, Lazarus, Norman R., Harridge, Stephen D.R., Sera from young and older humans equally sustain proliferation and differentiation of human myoblasts, Experimental Gerontology (2010Gerontology ( ), doi: 10.1016Gerontology ( /j.exger.2010 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Running title: Ageing serum and human satellite cell behaviour A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractUsing a human primary muscle cell culture model the behavior of myoblasts (satellite cells) cultured in human serum obtained from either young or elderly individuals was studied. Serum was obtained from a total of 13 young (7 male and 6 females aged, 23-36 years) and 9 elderly (4 male and 5 females aged 69-84 years) subjects and used in a number of experiments. Myoblasts were extracted from human muscle biopsy samples taken from the vastus lateralis. In the first experiment myoblasts were isolated immediately after extraction from the biopsy in media containing human sera to examine its effects on the onset and progression of Ki67 and desmin expression. No effect of the age of the serum was observed at 3, 5 or 7 days of proliferation. In addition, cells that had been expanded initially in optimum myoblast growth medium (GM, containing foetal calf serum and additional growth factors) prior to culture in medium containing 15% human serum were studied. The proportion of proliferating muscle cells co expressing desmin and Ki67 antigens after 46 hours was again similar in the young and old serum conditions. Culturing these myoblasts in media containing 2% human serum to study their fusion and differentiation also resulted in no difference between young and old serum conditions in terms of the percentage of nuclei inside myosin heavy chain positive myotubes. Despite the variability of different samples of myoblasts, the age of the serum has no affect on the expression of any measured index.

The influence of systemic inflammation on skeletal muscle in physically active elderly women

“…The rejuvenating action of young serum can be partly explained by the low systemic inflammatory status of young adults compared to older adults. It has previously been shown that myoblasts from young and old have similar myogenic behavior (Alsharidah et al 2013;George et al 2010) and that the age of the serum donor has no significant effect on the proliferative potential of myoblasts (Alsharidah et al 2013;George et al 2010), which together with our data suggests that the Fig. 4 The effect of exogenous CRP on the proportion of desmin+Ki-67+myoblasts at 12, 48, and 96 h of proliferation.…”

“…The influence of the systemic environment on skeletal muscle has been supported by the seminal work conducted by Conboy and collaborators who used a parabiotic model in mice to show an improvement of the regenerative capacity of injured old skeletal muscle exposed to a youthful systemic milieu (Conboy et al 2005). It has been shown that human myoblasts obtained from young and old donors have similar myogenic behavior (Alsharidah et al 2013;George et al 2010). However, the exposure of myogenic cells from old mice to serum from young mice induces an enhancement of the proliferative capacity (Conboy et al 2005).…”

“…Similar findings were reported in two other studies using human myogenic cells (Barberi et al 2013;Carlson et al 2009), indicating that the aged systemic environment can be the cause of the age-related decline in the proliferative rate of myoblasts. However, the chronological age of serum donors per se might not explain the deleterious effects of the systemic environment on myogenic cells as it has been shown that the ability of human myoblasts to proliferate is not impaired by culture in an aged milieu (George et al 2010). Therefore, we hypothesized that the level of systemic inflammation in elderly is an important factor able to influence skeletal muscle mass and the proliferative rate of myoblasts.…”

Reduction of myoblast differentiation following multiple population doublings in mouse C2C12 cells: A model to investigate ageing?

“…Indeed, parabiotic murine pairing studies have illustrated that a young systemic environment can fully rejuvenate the muscular phenotype of old mice [Conboy et al, 2005]. However, in light of recent evidence indicating increased expression of S100B (a negative regulator of differentiation) and reduced expression of RAGE (enhances differentiation) is important in the degenerative phenotypes observed in cells isolated from old versus young human muscle biopsies [Beccafico et al, 2010], and together with data illustrating that serum taken from young humans is unable to change the capacity of muscle cells isolated from elderly individuals to proliferate or differentiate [George et al, 2010], raises the question of the potential role of myoblast contribution to muscle regeneration across the lifespan.…”

Primary human muscle precursor cells obtained from young and old donors produce similar proliferative, differentiation and senescent profiles in culture

“…Biopsies were carried out as previously described (George et al, 2010). Muscle samples were obtained from the vastus lateralis muscle using the needle muscle biopsy technique (Bergstr€ om, 1962).…”