Reduced oxygen tension attenuates differentiation capacity of human mesenchymal stem cells and prolongs their lifespan

Abstract

SummaryMesenchymal stem cells (MSC) are capable of differentiating into bone, fat, cartilage, tendon and other organ progenitor cells. Despite the abundance of MSC within the organism, little is known about their in vivo properties or about their corresponding in vivo niches. We therefore isolated MSC from spongy (cancellous) bone biopsies of healthy adults. When compared with the surrounding marrow, a fourfold higher number of colony-forming units was found within the tight meshwork of trabecular bone surface. At these sites, oxygen concentrations range from 1% to 7%. In MSC cultured at oxygen as low as 3%, rates for cell death and hypoxia-induced gene transcription remained unchanged, while in vitro proliferative lifespan was significantly increased, with about 10 additional population doublings before reaching terminal growth arrest. However, differentiation capacity into adipogenic progeny was diminished and no osteogenic differentiation was detectable at 3% oxygen. In turn, MSC that had previously been cultured at 3% oxygen could subsequently be stimulated to successfully differentiate at 20% oxygen. These data support our preliminary finding that primary MSC are enriched at the surface of spongy bone. Low oxygen levels in this location provide a milieu that extends cellular lifespan and furthermore is instructive for the stemness of MSC allowing proliferation upon stimulation while suppressing differentiation.

Use of poly(DL-lactide-ε-caprolactone) membranes and mesenchymal stem cells from the Wharton's jelly of the umbilical cord for promoting nerve regeneration in axonotmesis: In vitro and in vivo analysis

“…Our results obtained from the in vitro testing of this cellular system show that during 96 h expansion, the undiffer-entiated HMSCs consumed glucose and produce, as expected, high concentration of lactate as a metabolic sub-product which is consistent with the Warburg effect and glycolysis stimulation. It was also described that MSCs do not require oxidative phosphor-ylation to survive ( Dos Funes et al, 2007) instead, hypoxia prolongs the lifespan of these cells, increases their proliferative capacity and reduces differentiation ( Fehrer et al, 2007). Several studies in recent years investigated the biological activity of HMSCs and their in vitro differentiation in neuroglial-like cells Mitchell et al, 2003).…”

Hypoxic reprograming of H3K27me3 and H3K4me3 at the INK4A locus

“…Mild hypoxia (1.5% and 3% O 2 ) prevented cellular senescence in mouse embryonic fibroblasts, human mesenchymal stem cells, and human fibroblasts but enhanced cell proliferation [31][32][33]. However, the correlation between hypoxia and senescence is controversial.…”

Controversial issue: Is it safe to employ mesenchymal stem cells in cell-based therapies?

“…In 1961, Hayflick and Moorhead discovered that in vitro, human skin fibroblasts undergo only a limited number of population doublings (termed Hayflick limit), and that this number decreased with increasing donor age (Hayflick and Moorhead, 1961). Similar to other human diploid cells, MSC exhibit replicative senescence in vitro, as demonstrated by a number of investigators (Fehrer et al, 2007;Kern et al, 2006;Stenderup et al, 2003;Stenderup et al, 2004;Stolzing et al, 2008). The in vitro senescent phenotype includes the following characteristic features: (i) irreversible arrest of cell division (in contrast to quiescence, where this lock is reversible), (ii) resistance to apoptotic death, and (iii) the excretion of molecules normally secreted during wound repair and infection, such as inflammatory cytokines, proteases and growth factors, the latter having detrimental consequences for the surrounding tissue (Campisi, 2001).…”

“…The in vitro senescent phenotype includes the following characteristic features: (i) irreversible arrest of cell division (in contrast to quiescence, where this lock is reversible), (ii) resistance to apoptotic death, and (iii) the excretion of molecules normally secreted during wound repair and infection, such as inflammatory cytokines, proteases and growth factors, the latter having detrimental consequences for the surrounding tissue (Campisi, 2001). Some, but not all of these characteristics have also been described for MSC cultures (Fehrer et al, 2007;Kern et al, 2006;Stenderup et al, 2003;Stenderup et al, 2004;Stolzing et al, 2008)…”