Original articleAging is associated with decreased maximal life span and accelerated senescence of bone marrow stromal cells,☆
Introduction
Several clinical and histomorphometric studies have demonstrated that aging is associated with decreased bone mass and that decreased bone formation is an important pathogenetic factor [1], [2], [3]. However, the cellular and molecular mechanisms underlying decreased bone formation are not known in detail. Osteoblasts (the bone-forming cells) are recruited continuously from stem and osteoprogenitor cells in the bone marrow during the bone formation phase of skeletal remodeling [3]. While the identity of these stem cells has not been determined, it is generally accepted that they are present in bone marrow stromal cells (MSC) based on their ability for extensive cellular proliferation and multipotentiality [4], [5], [6].
Depletion of stem cells has been suggested to contribute to a large number of degenerative diseases of brain, liver, skin, and bone marrow [7]. Previous studies examining age-related effects on the size of the osteoprogenitor cell population in bone marrow have yielded variable results. Some studies in rodents and humans reported an age-related decrease in the number of osteoprogenitor cells [8], [9], [10], [11], [12] while other studies found no effects or an age-related increase [13], [14], [15], [16]. We have previously examined the number of osteoprogenitor cells generated in Stro-1 purified MSC cultures from a large number of normal healthy young and old donors as well as patients with osteoporosis [17]. We found maintenance of the number and the proliferative capacity of osteoprogenitor cells with aging and in patients with osteoporosis. However, this study examined the proliferative capacity of the cells in short-term cultures (2 weeks).
Long-term in vitro culture of normal diploid cells (the so-called Hayflick model of cellular senescence) has been employed extensively in the field of biogerontology to identify the cellular mechanisms of age-related impairment of functions [18], [19], [20]. In this model, cultured cells exhibit arrest of proliferation after a variable number of population doublings (PD) and characteristic biochemical and molecular changes that are dependent on the age of the donor [21], [22], [23] and on disease condition [24]. We have also, previously, employed this model to study the senescence phenotype of human osteoblasts derived from trabecular bone explants [25], [26], [27]. In the current study, we characterized the long-term in vitro growth and biological characteristics of MSC cultures obtained from both young and old healthy donors.
Section snippets
Study population
Eleven individuals participated in the study: six young adults (four females and two males) aged 18–29 years and five elderly women aged 66–81 years. The participants were recruited from the local community and they had no history of concurrent illness or intake of medication that could affect bone metabolism. The study was conducted according to the ethical guidelines of the Declaration of Helsinki and was approved by the Regional Scientific-Ethical Committee. All participants signed an
Long-term culture of human MSC
Long-term growth of MSC showed characteristics typical of the Hayflick model of cellular aging known from other diploid cells including osteoblasts [25]. Fig. 1 is a plot of MSC growth as a percentage of life span completed versus time of growth allowing comparison of the results between different cell strains. Life span of MSC can be divided into three phases depending on their in vitro age: a phase of rapid cell growth (phase 1: <50% of life span completed) followed by a phase of reduced
Discussion
The present study demonstrates that MSC exhibit the characteristics typical of the Hayflick model of cellular senescence with a limited life span, telomere shortening, accumulation of SA β-gal+ cells, and impairment of functions. Furthermore, cells obtained from elderly donors exhibited decreased proliferation potential and accelerated senescence compared with cells obtained from younger donors.
We found clear differences in the growth pattern of MSC obtained from young and old donors with a
Acknowledgements
We thank Dr. Frederik Dagnaes-Hansen for assistance with animal experiments, Claus Bischoff for assistance, with telomere experiments, and Lotte Sørensen for technical assistance.
References (52)
- et al.
Age- and sex-related changes in iliac cortical bone mass and remodeling
Bone
(1993) - et al.
Thickness of bone formed at remodeling sites in normal human iliac trabecular bonevariations with age and sex
Metab Bone Dis Relat Res
(1983) - et al.
Stem cells and agingexpanding the possibilities
Mech Ageing Dev
(2001) - et al.
The number of fibroblastic colonies formed from bone marrow is decreased and the in vitro proliferation rate of trabecular bone cells increased in aged rats
Bone
(1992) - et al.
Effects of donor age on osteogenic cells of rat bone marrow in vitro
Mech Ageing Dev
(1990) - et al.
An in vitro analysis of murine hemopoietic fibroblastoid progenitors and fibroblastoid cell function during aging
Mech Ageing Dev
(1983) From cells to organismscan we learn about aging from cells in culture?
Exp Gerontol
(2001)- et al.
The serial cultivation of human diploid cell strains
Exp Cell Res
(1961) Ageing—a biological perspective
Mol Aspects Med
(1995)- et al.
Telomere shortening during aging of human osteoblasts in vitro and leukocytes in vivolack of excessive telomere loss in osteoporotic patients
Mech Ageing Dev
(1999)
Rapidly forming apatitic mineral in an osteoblastic cell line (UMR 106-01 BSP)
J Biol Chem
Variations in the stromal cell population of human bone marrow during aging
Mech Ageing Dev
In vivo loss of telomeric repeats with age in humans
Mutat Res
Identification of mesenchymal stem/progenitor cells in human first-trimester fetal blood, liver, and bone marrow
Blood
Bone Forming Cells in Clinical Conditions
Bone marrow stromal cellscharacterization and clinical application
Crit Rev Oral Biol Med
Multilineage potential of adult human mesenchymal stem cells
Science
Isolation and characterization of osteoblast precursor cells from human bone marrow
J Bone Miner Res
Age-related changes in osteogenic stem cells in mice
J Bone Miner Res
Age-related osteogenic potential of mesenchymal stromal stem cells from human vertebral bone marrow
J Bone Miner Res
Bone progenitor cell deficits and the age-associated decline in bone repair capacity
Calcif Tissue Int
Number of osteoprogenitor cells in human bone marrow markedly decreases after skeletal maturation
J Bone Miner Metab
Skeletal progenitor cells and ageing human populations
Clin Sci (Colch)
Stromal colonies from mouse marrowcharacterization of cell types, optimization of plating efficiency and its effect on radiosensitivity
J Cell Sci
Number and proliferative capacity of osteogenic stem cells are maintained during aging and in patients with osteoporosis
J Bone Miner Res
The effect of donor age on the in vitro life span of cultured human arterial smooth-muscle cells
In Vitro
Cited by (1036)
Dietary supplementation with nacre reduces cortical bone loss in aged female mice
2023, Experimental GerontologyiPSC-derived mesenchymal stem cells attenuate cerebral ischemia-reperfusion injury by inhibiting inflammatory signaling and oxidative stress
2023, Molecular Therapy Methods and Clinical DevelopmentAnti-aging effects of the pistachio extract on mesenchymal stem cells proliferation and telomerase activity
2023, Archives of Gerontology and GeriatricsAging – What it is and how to measure it
2023, Mechanisms of Ageing and DevelopmentComparison of stem cell characteristics between perichondral-derived stem cells and periosteal stem cells in postnatal rats
2023, Medicine in Novel Technology and Devices
- ☆
☆ This work was supported by grants from Danish Medical Research Council, Novo Nordisk Foundation, Danish Center for Stem Cell Research, Karen Elise Jensen's Foundation, and Albani Foundation.☆,☆☆
- *
These authors contributed equally to this work.