Neurobionplus
Home About Journal AHEAD OF PRINT Current Issue Back Issues Instructions Submission Search Subscribe Blog    
Login 

Users Online: 1034 
Print this page  Email this page Small font sizeDefault font sizeIncrease font size 
 


 
 Table of Contents    
ORIGINAL ARTICLE  
Year : 2013  |  Volume : 47  |  Issue : 6  |  Page : 565-571
Osteogenic potentials of osteophytes in the cervical spine compared with patient matched bone marrow stromal cells


1 Department of Orthopaedics, The First Affiliated Hospital of Chongqing Medical University, 1, Youyi Road, Yuanjiagang Yuzhong District, Chongqing, China
2 Department of Orthopaedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan - 430030, China
3 Department of Orthopaedics, The First Affiliated Hospital of Chongqing Medical University, 1, Youyi Road, Yuanjiagang Yuzhong District, Chongqing; Department of Orthopaedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan - 430030, China

Click here for correspondence address and email

Date of Web Publication19-Nov-2013
 

   Abstract 

Background: Osteophytes that form adjacent to degenerated disc have osteogeic potential. Studies suggest that their formation is associated with mesenchymal precursors arising from the chondrosynovial junction. This study is aimed to determine the cellular aging and osteogenic differentiation potential of osteophyte-derived mesenchymal cells (oMSCs) when compared to patient-matched bone marrow stromal cells (bMSCs).
Materials and Methods: oMSCs and bMSCs were isolated from tissue samples during anterior cervical discectomy and fusion surgery. Extensive expansion of cell cultures was performed and early and late passage cells (P 4 and P 9 , respectively) were used to study cell senescence and telomerase activity. Furthermore, osteogenic differentiation was applied to detect their osteogenic capacity.
Results: The proliferation capacity of oMSCs in culture was superior to that of bMSCs and these cells readily underwent osteogenic differentiation. Our results showed that oMSCs had higher telomerase activity in late passages compared with bMSCs, although there was no significant difference in the telomerase activity in the early passages in either cell types. The telomerase activity was detectable only in early passage oMSCs and not in bMSCs.
Conclusions: Our results indicate that oMSCs retain a level of telomerase activity in vitro, which may account for the relatively greater longevity of these cells, compared to bMSCs. Furthermore, when compared to bMSCs, oMSCs maintained a higher proliferative capacity and the same osteogenic capacity, which may offer new insights of tissue formation.

Keywords: Cervical spine, mesenchymal stromal cells, osteogenesis, osteophyte, telomerase activity

How to cite this article:
Zhao P, Ni W, Jiang D, Xiong W, Li F, Luo W. Osteogenic potentials of osteophytes in the cervical spine compared with patient matched bone marrow stromal cells. Indian J Orthop 2013;47:565-71

How to cite this URL:
Zhao P, Ni W, Jiang D, Xiong W, Li F, Luo W. Osteogenic potentials of osteophytes in the cervical spine compared with patient matched bone marrow stromal cells. Indian J Orthop [serial online] 2013 [cited 2019 Nov 22];47:565-71. Available from: http://www.ijoonline.com/text.asp?2013/47/6/565/121579

   Introduction Top


Osteophytes are bony spur-like formations and are a distinctive feature of degenerative disc diseases. The function of osteophyte is not clear although it is regarded as the body's attempt to re-balance the load bearing of spine in order to recuperate the degenerated disc. Formation of osteophytes adjacent to a degenerated disc is often implicated to cause compression of the spinal cord and/or nerves. [1],[2]

Recently developed cervical interbody cages and plate- screw devices offer the advantages of decreasing segmental flexibility and promoting a load-sharing environment in cervical spine reconstruction. [3],[4] Advances in bone graft technology have led to investigation of various osteoinductive materials for their ability to regulate and enhance skeletal bone formation and repair. [5],[6] However, higher resorption rates and lower osteogenic potential frequently compromise their ability to promote successful spinal fusion. [7],[8]

As we know, osteophytes which cause compression are excised during spine surgery. If the osteophyte had the qualified osteogenic potential, then it could be used as bone formation material in cervical interbody fusion surgery. Studies involving the ultrastructure of osteophytes suggest that their formation is associated with mesenchymal precursors arising from the chondrosynovial junction [9] and it is regulated by a similar molecular mechanism of normal bone embryogenesis. Osteophytes have been found to consist of three different mesenchymal tissue regions, including endochondral bone formation within cartilage residues, intramembranous bone formation within fibrous tissue and bone formation within bone marrow spaces. The presence of bone and cartilage derived morphogenetic proteins in osteophytes indicates active bone formation. [10] All of these features provide evidence of involvement of mesenchymal cells in osteophyte formation; nevertheless, this involvement remains to be characterized.

We aim to determine the cellular aging and osteogenic differentiation potential of osteophyte-derived mesenchymal cells (oMSCs). As the mesenchymal cells that form bone marrow (bMSCs) have a central role in the regenerative medicine, we compare it with oMSCs from the same patient. Till date no studiess have comprehensively evaluated the oetsogenic properties of osteophytes in the cervical spine.


   Materials and Methods Top


Sample collection

Tissue samples were collected from six patients following informed consent. The patients were between 55 and 67 years of age group undergoing anterior cervical discectomy and fusion surgery (four males and two females). Osteophyte tissues were obtained around the uncovertebral articulations and the spur of the vertebral body (four for C5 and two for C4). Bone marrow was also collected from the same patients by bone marrow aspirate from the vertebral body. The sample collection was done in accordance with the terms of the Human Ethics Committees of our institution.

Cell isolation and in vitro expansion

The osteophyte tissues were placed aseptically in sterile containers with 10 ml of Hanks' buffer (GIBCO, Invitrogen Corporation, USA). Small pieces (2 mm thick and 2 × 4 mm [2] ) were dissected from the tissue for explant culture. [11],[12] Briefly, the tissue fragments were placed in six well plates with 2 ml of culture medium, low glucose Dulbecco modified Eagle medium (DMEM-LG; GIBCO, Invitrogen Corporation, USA) supplemented with 10% fetal bovine serum (FBS; HyClone, USA) and 1% penicillin and streptomycin (P/S) (GIBCO, Invitrogen Corporation, USA). The expanded cells were trypsinized and cultured in a T-75 flask for future characterization. The cell surface marker (mesenchymal/stromal stem cells: CD90, CD105 and CD73) were used to detect its mesenchymal and stromal origin with fluorescence-activated cell sorter (FACS). For each assay, 5 × 10 [5] cells were collected using 0.25% trypsin, fixed with 70% ice-cold ethanol and treated with 0.02 mg/ml RNase and EDTA. The DNA was stained with 0.1 mg/ml propidium iodide (PI). Cells were incubated in dark for 30 min and then filtered using 70 mm cell strainers. Samples were analyzed on an FACS (Becton Dickinson, San Jose, USA) and using the standard procedure of the Cell Quest software and the ModFitLT software version 3 (Becton Dickinson).

Isolation and culture of bone marrow-derived MSCs (bMSCs)were performed according to the previously published method in our lab. [13] Briefly, the suspension of gelatinous bone marrow was filtered through a 74 mm nylon mesh and then cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 1% penicillin, 100 mg/ml streptomycin and 10% fetal bovine serum (FBS) on 25 cm [2] plastic flasks in 37°C with 5% CO [2] . After 24 hrs, the nonadherent cells were removed by refreshing the medium and thereafter the medium was refreshed every 3-4 days. After 14 days, cells reached confluence.

Cell proliferation

To compare the capacity of cell proliferation between oMSCs and bMSCs, cell proliferation was conducted at the P 4 and P 9 using 3H leucine incorporation assay. [13] All experiments were performed in triplicate.

Cell senescence assay

Cytochemical staining for senescence associated b-galactosidase assay was performed using a b-galactosidase staining kit. Cells from P 4 and P 9 were seeded at a density of 2 × 10 [4] /well into four-well plates and allowed to attach overnight, then washed with PBS, fixed and incubated overnight at 37.8°C with X-gal chromogenic substrate at pH 6.0 according to manufacturer's protocol. The color development was observed under light microscope and the image was captured at 100× magnification. The percentage of stained cells as calculated from the averages from five MSC cultures from both early and late passages.

Telomerase activity assay

Telomerase activity in P 4 and P 9 oMSC and bMSC was assayed by a PCR-based assay designated telomere repeat amplification protocol (TRAP) (for telomeric repeated protocol) as telomerase assay kit (Dingguo, Inc., Beijing) described. In the TRAP assay, telomerase synthesized extension products then served as the templates for PCR amplification. The extended products were amplified for 35 cycles (94°C × 30 s, 55°C × 30 s, 72 °C ×1 min) after 3 min at 90°C. A typical assay gives several ladders with interval of 6 bp length DNA, reflecting the addition of one telomerase repeat unit. The size of ladders was representative of telomerase activity. Digital pictures were taken and analyzed using image analysis software (Genescan, ABI, USA). Relative gray value was used to reflect the DNA content of the ladder.

Osteogenic differentiation

Cells (oMSCs and bMSCs) in T-25 culture flask were cultured in growth medium (DMEM with10% FSC, 1% Penicillin-Streptomycin, 1% Glutamine) at 37°C in a 5% CO 2 humidified incubator. When cells were approximately 80-90% confluent, dissociation with Trypsin-EDTA was performed. Cells were replated in growth medium at 3 × 10 [3] cells/cm [2] in 6-well tissue culture plates with a medium volume of 2 mL per well. Cells were incubated at 37°C in a 5% CO 2 humidified incubator. We aspirated off the growth medium from each well and then added 2 mL osteogenic differentiation medium (DMEM with 10% FSC, 1% Penicillin-Streptomycin, 1% Glutamine, 50 μg/ml Ascorbate, 10 mmol/L β-Glycerophosphate, 10[8] mol/L Dexamethasone) after 24 hrs.

This medium was changed twice weekly for up to 3 weeks. Following 4% paraformaldehyde fixation, cell and matrix mineralization was detected by Alizarin red stain for calcium deposits.

Osteogenic assays

Cells were plated for osteogenic differentiation as above for up to 28 days, with medium changed three times per week. Samples were harvested in triplicate for the following assays. The alkaline phosphatase (ALP) activity in cell lysates was measured using SensoLyte pNPP Alkaline Phosphatase Assay Kit (AnaSpec, San Jose, CA) following the manufacturer's instructions and normalized to total protein content through the Bradford assay (Bio-Rad, Hercules, CA).

Semiquantitative polymerase chain reaction

We undertook reverse transcription-polymerase chain reaction (RT-PCR) of the following osteogenic genes: [14] Osteonectin and ALP [Table 1]. PCRs were performed in triplicate. Thermal cycle conditions were 50°C for 2 min, 95°C for 10 min, then 50 cycles at 95°C for 15 s and 60°C for 1 min. Amplifications were monitored with the ABI Prism 7000 Sequence Detection System (Applied Biosystems). Results were normalized against the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH).
Table 1: Design of primers and probes


Click here to view


Statistical analysis

The experiment was repeated three times. All data are represented as the Mean ± SD and statistical analysis was carried out employing the SPSS software package (Version 12.0). Data was analyzed using the independent-samples t test. (P < 0.05 was considered statistically significant).


   Results Top


Cell culture and morphology

Within 3 days, cells started to migrate out from the osteophyte tissues and these cells showed a spear-like morphology and divided actively [Figure 1]a-i. The cells were confluent within 3 weeks, yielding approximately 3 × 10 [5] cells from each piece of sample [Figure 1]a-ii. The osteophyte cells exhibited an attachment growth and acquired a fibroblast-like morphology when they were expanded after the first passage [Figure 1]a-iii. No obvious morphological difference could be detected between oMSCs [Figure 1]a-iii and bMSCs [Figure 1]a-iv after the first passage.
Figure 1: Characterization of oMSCs and bMSCs. (a) All MSC sources demonstrated a spindle-shaped morphology (100×). (i) oMSCs started to come off the tissue in 3 days; (ii) oMSCs were confluent within 3 weeks; (iii) oMSCs exhibited an attachment growth and acquired a fibroblast-like morphology when they were expanded after the first passage; (iv) bMSCs from the same patients after the first passage. (b) In the early passages, both oMSCs and bMSCs showed a similar proliferation rate with a similar increase in cell numbers over 7 days. (c) In the later passages, oMSCs showed a significant increase in cell numbers compared with bMSCs; *P<0.05 vs control

Click here to view


The proliferation capacity of osteophyte-derived mesenchymal cells

To assess the effect of extensive passaging on cell proliferation, the [3H] leucine incorporation assay was used to monitor cell proliferation. In an early passage (P 4 ), both oMSCs and bMSCs showed a similar proliferation rate with a similar increase in cell numbers over 7 days. At a later passage (P 9 ), oMSCs showed a significant increase in cell numbers compared with bMSCs (P < 0.05) from day 7 to day 21 [Figure 1]b and [Figure 1]c.

β-Galactosidase expression in osteophyte-derived mesenchymal cells and bone marrow stromal cells

β-Galactosidase staining in both oMSCs and bMSCs cultures increased with the number of passages [Figure 2]a. Interestingly, bMSCs showed significantly higher cell numbers with the expression of β-galactosidase compared to oMSCs in P 9 . The number of β-galactosidase-positive cells in early passage was low at 2-24% in oMSCs and 5-27% in bMSCs at P 4 culture; however, at P 9 β-galactosidase-positive cells increased to 12-37% in oMSCs and 58-90% in bMSCs [Figure 2]a. The percentage of β-galactosidase-positive cells in bMSCs was significantly higher than that in oMSCs. In bMSCs increase of β-galactosidase-positive cells in the late passage was correlated with the decrease of cell proliferation. There was a significant increase in cell proliferation in P 9 bMSCs compared with P 4 bMSCs and P 9 oMSCs.
Figure 2: The aging of the MSCs. (a) ß-Galactosidase expression in osteophyte-derived mesenchymal cells and bMSCs (P4 and P9). The percentage of ß-galactosidase-positive cells in bone marrow stromal cells was significantly higher than that in oMSCs. (b) The telomerase activity of MSCs. The extension ladders from bMSCs were less than that from oMSCs both in P4 and in P9 *P<0.05

Click here to view


Telomerase activity of marrow stromal cells

The telomerase activity of MSCs was determined by TRAP. The more and larger amplified products were, the higher telomerase activity. The extension ladders from bMSCs were less than that from oMSCs both in P 4 and in P 9 . Image analysis of digital pictures showed the extension products' relative gray value from bMSCs was lower than that from oMSCs (P < 0.05) [Figure 2]b. This suggests that cell passaging reduces the telomerase activity of MSCs.

Osteogenic differentiation assays by alizarin red stain

The results showed that the number of osteocytes, which were derived from oMSCs [Figure 3]a-i after 7d culture, were much higher than that from bMSCs [Figure 3]a-ii.
Figure 3: Markers for induced osteogenesis of osteophyte-derived mesenchymal cells. (a,b): Alizarin red stain for calcium deposits: the number of osteocytes, which were derived from oMSCs [Figure b] after 7d culture, was much higher than that from bMSCs [Figure a]. (c) The ALP activity by PNPP (P4 P9), the ALP activity were lower in cells from bMSCs group than that from the oMSCs group *P<0.05. Bar: 100 m

Click here to view


Osteogenic differentiation assays by the alkaline phosphatase activity

After induction with osteogenic inducer, the ALP activity, as markers of osteoblasts, were lower in cells from bMSCs group than that from oMSCs group (P < 0.05) [Figure 3]b. This indicates that cell from osteophytes have a bigger osteogenic differentiation capacity.

Osteogenic differentiation assays by semiquantitative polymerase chain reaction

When exposed to osteogenic medium over 28 days, oMSCs underwent more robust osteogenic differentiation, generating more extracellular mineralization than the other MSC types, as shown by more intense alizarin red staining [Figure 3]b and c. Two osteogenic genes were upregulated earlier (ALP) or more robustly (osteonectin) in oMSCs than in bMSCs. oMSCs demonstrated earlier expression of osteonectin and higher expression of ALP than bMSCs [Figure 4].
Figure 4: Osteogenic differentiation assays by reverse transcription-polymerase chain reaction. All two osteogenic genes were upregulated earlier (ALP) or more robustly (osteonectin) in oMSCs than in bMSCs. (a) mRNA expression of ALP and osteonectin. (b, c) image analysis of digital pictures of products relative gray value. *P<0.05

Click here to view



   Discussion Top


Osteophyte is a frequent cause of cervical spondylotic myelopathy and radiculopathy in people over the age of 50 years. [1],[2],[3],[4] Variations in stress and strain in the spinal structure adjacent to a degenerated disc may affect spinal stability, which lead to the formation of osteophytes. [15],[16] The osteophytes re-balance the load bearing surface of the cervical spine in order to recuperate the degenerated disc, with the aim to re-gain spinal stability. Unfortunately, osteophytes cause nerve compression (nerve roots and/or spinal cord) in the process of re-balancing. A discectomy followed by spinal fusion is considered the classic procedure in the treatment of symptomatic cervical spine pathology. Interbody cage with or without osteo-inductive materials (such as autogenous or allogenic bone, allogenic or ceramic materials and growth factors) is one of the choices for spinal fusion. [5],[6],[17],[18] High quality scaffolds with bMSCs are reasonable solutions for bone graft materials in recent basic research and have already been in clinical application. [18] In this study we evaluated the osteogenic differentiation potential of oMSCs, with the aims to verify its ability as an osteo-inductive material. We found that oMSCs were capable of retaining proliferative capacities at higher passage numbers when compared with patient-matched bMSCs. We further found that the proliferative potential of MSCs from bone marrow and osteophytes appeared to be closely linked to telomere length, which is controlled by telomerase activity. However, there was no statistical significance in oMSC proliferation between P 9 and P 4 , even though telomerase activity was significantly decreased in P 9 oMSCs. The significantly higher telomerase activity in the early passage oMSCs (P 4 ) may be responsible for the maintenance of proliferation in P 9 oMSCs. Previous studies have showed that stem cells in their niches have longer telomeres in comparison to their more differentiated counterparts. [19],[20] Our results, together with the previous studies, [12],[20] show the higher proliferating ability of OMSCs. This is good for quantity, but bad for quality in some way. Cell may be more prone to undergo malignant transformation in the proliferating process. Even though MSCs derived from healthy tissues do not appear to exhibit tumorigenic characteristics, [21] it remains unclear whether MSCs derived from diseased tissues, such as osteophytes, show adverse cytogenetic variation in comparison to MSCs from bone marrow. Previous studies showed that osteophyte tissues contain pools of MSCs which exhibit normal traits, enter senescence after extended in vitro culture and have a normal karyotype compared to bMSCs. [20] Furthermore, the aim of our research was to verify the utility of vertebral body spur transplantation; we did not need a vitro cellular proliferation. Previous work has suggested that chondrogenesis and osteogenesis during the formation of osteophyte tissue may be similar to that seen during normal bone development; [12],[22] hence, we assessed oMSC differentiation into cells of the osteophytes lineages. In contrast to a previous study showing that nonbone marrow-derived MSCs have a reduced differential capacity, [23] our study showed oMSCs differentiate in a manner similar to bMSCs and were able to form a denser cellular matrix during osteogenesis. In terms of osteogenic differentiation, oMSCs demonstrated similar differentiation capacities in comparison to bMSCs. Interestingly, in one bMSC sample during osteogenic differentiation, an absence of calcium deposition was noted, but it was present in the comparative oMSCs. We further confirmed lack of osteopontin expression in the bMSCs and positive expression in the same patient's oMSCs. It has been revealed that there may be an age-related decline in osteogenic potential in bMSCs. [24],[25],[26] Our results support the possibility that the differentiation potential oMSCs is not affected by age.

The concept of 'age-dependent' expression in cell cultures was very distinct, not only between passages, but also between cell sources. [27],[28] When compared to our previously reported results for cell proliferation, [12],[20] oMSCs appeared to have either more primitive cells or be somehow more resistant to aging. Various studies have indicated that cellular aging may be, in part, due to critical size telomere length that leads to replicative senescence. [29],[30],[31],[32] Evidence suggests that stem cells maintain longer telomeres relative to other cells within the tissue, such as in lingual mucosa, where in situ hybridization has revealed longer telomeres in the basal cells [33] and stem cell compartments of the skin, small intestine, cornea, testis and brain. [19]

In summary, we have isolated and characterized a cell population from osteophyte tissue in cervical spine. These osteophyte tissues contain pools of MSCs that exhibit normal traits. We noted that unlike bMSCs, these cells maintained their proliferative capacity at late passage and had a slightly higher osteogenic differential capacity, which indicates that these cells may offer an alternative to bMSCs in some way.

 
   References Top

1.Friedenberg ZB, Miller WT. Degenerative disc disease of the cervical spine. J Bone Joint Surg Am 1963;45:1171-8.  Back to cited text no. 1
[PUBMED]    
2.Lestini W, Wiesel S. The pathogenesis of cervical spondylosis. Clin Orthop Rel Res 1989;239:69-93.  Back to cited text no. 2
    
3.Wigfield CC, Nelson RJ. Nonautologousinterbody fusion materials in cervical spine surgery: How strong is the evidence to justify their use? Spine (Phila Pa 1976) 2001;26:687-94,  Back to cited text no. 3
    
4.Wilke HJ, Kettler A, Claes L. Primary stabilizing effect of interbody fusion devices for the cervical spine: An in vitro comparison between three different cage types and bone cement. Eur Spine J 2000;9:410-6.  Back to cited text no. 4
[PUBMED]    
5.Walsh W, Nicklin S, Loefler A, Yu Y, Arm D, Gillies M. Autologous growth factor gel (AGF) and spinal fusion. Orthop Res Soc Trans 2001;26:951.  Back to cited text no. 5
    
6.Zdeblick TA, Ghanayem AJ, Rapoff AJ, Swain C, Bassett T, Cooke ME. Cervical interbody fusion cages. An animal model with and without bone morphogenetic protein. Spine (Phila Pa 1976) 1998;23:758-66.  Back to cited text no. 6
    
7.Sandhu HS, Boden SD. Biologic enhancement of spinal fusion. Orthop Clin North Am 1998;29:621-31.  Back to cited text no. 7
[PUBMED]    
8.Walsh WR, Harrison J, Loefler A, Martin T, Van Sickle D, Brown MK. Mechanical and histologic evaluation of Collagraft in an ovine lumbar fusion model. Clin Orthop Relat Res 2000;375:258-66.  Back to cited text no. 8
    
9.Blom AB, van Lent PL, Holthuysen AE, van der Kraan PM, Roth J, van Rooijen N, et al. Synovial lining macrophages mediate osteophyte formation during experimental osteoarthritis. Osteoarthritis Cartilage 2004;12:627-35.  Back to cited text no. 9
[PUBMED]    
10.Zoricic S, I Maric, D Bobinac and S Vukicevic. Expression of bone morphogenetic proteins and cartilagederived morphogenetic proteins during osteophyte formation in humans. J Anat 2003;202:269-77.  Back to cited text no. 10
    
11.Nöth U, Osyczka AM, Tuli R, Hickok NJ, Danielson KG, Tuan RS. Multilineagemesenchymal differentiation potential of human trabecular bone-derived cells. J Orthop Res 2002;20:1060-9.  Back to cited text no. 11
    
12.Singh S, Jones BJ, Crawford R, Xiao Y. Characterization of a mesenchymal-like stem cell population from osteophyte tissue. Stem Cells Dev2008;17:245-54.  Back to cited text no. 12
[PUBMED]    
13.Wei L, Wei X, Jun Z, Zhong F, Wenjian CH, Yubo F, et al. Laminar shear stress delivers cell cycle arrest and anti-apoptosis to mesenchymal stem cells. Acta Biochim Biophys Sin (Shanghai) 2011;43:210-6.  Back to cited text no. 13
    
14.Cawthon RM. Telomere measurement by quantitative PCR. Nucleic Acids Res 2002;30:e47.  Back to cited text no. 14
[PUBMED]    
15.Buckwalter JA. Aging and degeneration of the human interverteral disc. Spine (Phila Pa 1976) 1955;20:1307-14.  Back to cited text no. 15
    
16.Ghosh P. Biology of the interverbral disc. Boca Raton, FL: CRC Press; 1988.  Back to cited text no. 16
    
17.Lowery GL, Kulkarni S, Pennisi AE. Use of autologous growth factors in lumbar spinal fusion. Bone 1999;25(2 Suppl):47S-50S.  Back to cited text no. 17
    
18.Marchesi DG. Spinal fusions: Bone and bone substitutes. Eur Spine J 2000;9:372-8.  Back to cited text no. 18
[PUBMED]    
19.Flores I, Canela A, Vera E, Tejera A, Cotsarelis G, Blasco MA. The longest telomeres: A general signature of adult stem cell compartments. Genes Dev 2008;22:654-67.  Back to cited text no. 19
[PUBMED]    
20.Singh S, Dhaliwal N, Crawford R, Xiao Y. Cellular senescence and longevity of osteophyte-derived mesenchymal stem cells compared to patient-matched bone marrow stromal cells. J Cell Biochem 2009;108:839-50.  Back to cited text no. 20
[PUBMED]    
21.Bernardo ME, Zaffaroni N, Novara F, Cometa AM, Avanzini MA, Moretta A, et al. Human bone marrow derived mesenchymal stem cells do not undergo transformation after long-term in vitro culture and do not exhibit telomere maintenance mechanisms. Cancer Res 2007;67:9142-9.  Back to cited text no. 21
[PUBMED]    
22.Alonge TO, Rooney P, Oni OO. The ultrastructure of the peri-articular osteophytes-an evaluation by scanning electron microscopy. West Afr J Med 2005;24:147-50.  Back to cited text no. 22
[PUBMED]    
23.Im GI, Shin YW, Lee KB. Do adipose tissue derived mesenchymal stem cells have the same osteogenic and chondrogenic potential as bone marrow-derived cells? Osteoarthritis Cartilage 2005;13:845-53.  Back to cited text no. 23
[PUBMED]    
24.D'Ippolito G, Schiller PC, Ricordi C, Roos BA, Howard GA. Age-related osteogenic potential of mesenchymal stromal stem cells from human vertebral bone marrow. J Bone Miner Res 1999;14:1115-22.  Back to cited text no. 24
[PUBMED]    
25.Mendes SC, Tibbe JM, Veenhof M, Bakker K, Both S, Platenburg PP, et al. Bone tissue-engineered implants using human bone marrow stromal cells: Effect of culture conditions and donor age. Tissue Eng 2002;8:911-20.  Back to cited text no. 25
[PUBMED]    
26.Mueller SM, Glowacki J. Age-related decline in the osteogenic potential of human bone marrow cells cultured in three-dimensional collagen sponges. J Cell Biochem 2001;82:583-90.  Back to cited text no. 26
[PUBMED]    
27.Dimri GP, Lee X, Basile G, Acosta M, Scott G, Roskelley C, et al. A biomarker that identifies senescent human cells in culture and in aging skin in vivo. Proc Natl Acad Sci USA 1995;92:9363-7.  Back to cited text no. 27
[PUBMED]    
28.Fehrer C, Brunauer R, Laschober G, Unterluggauer H. Reduced oxygen tension attenuates differentiation capacity of human mesenchymal stem cells and prolongs their lifespan. Aging Cell 2007;6:745-57.  Back to cited text no. 28
    
29.Yang Q. Cellular senescence, telomere recombination and maintenance. Cytogenet Genome Res 2008;122:211-8.  Back to cited text no. 29
[PUBMED]    
30.Britt-Compton B, Wyllie F, Rowson J, Capper R, Jones RE, Baird DM. Telomere dynamics during replicative senescence are not directly modulated by conditions of oxidative stress in IMR90 fibroblast cells. Biogerontology C 2009;10:683-93.  Back to cited text no. 30
    
31.Hanna CW, Bretherick KL, Gair JL, Fluker MR, Stephenson MD, Robinson WP. Telomere length and reproductive aging. Hum Reprod 2009;24:1206-11.  Back to cited text no. 31
[PUBMED]    
32.Wu YH, Cheng ML, Ho HY, Chiu DT, Wang TC. Telomerase prevents accelerated senescence in glucose-6-phosphate dehydrogenase (G6PD)-deficient human fibroblasts. J Biomed Sci 2009;16:18.  Back to cited text no. 32
[PUBMED]    
33.Aida J, Izumiyama-Shimomura N, Nakamura K, Ishikawa N, Poon SS, Kammori M, et al. Basal cells have longest telomeres measured by tissue Q-FISH method in lingual epithelium. Exp Gerontol 2008;43:833-9.  Back to cited text no. 33
[PUBMED]    

Top
Correspondence Address:
Wei Xiong
The First Affiliated Hospital Chongqing Medical University, 1 Youyi Rd Chongqing - 400016
China
Login to access the Email id

Source of Support: This work was supported by a grant from the National Natural Science Foundation of China (No. 30772206), Conflict of Interest: None


DOI: 10.4103/0019-5413.121579

Rights and Permissions


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1]

This article has been cited by
1 Age-related changes in osteometry, bone mineral density and osteophytosis of the lumbar vertebrae in Japanese macaques
Porrawee Pomchote
Primates. 2014;
[Pubmed] | [DOI]



 

Top
 
 
 
  Search
 
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  
 


 
    Abstract
   Introduction
    Materials and Me...
   Results
   Discussion
    References
    Article Figures
    Article Tables
 

 Article Access Statistics
    Viewed1751    
    Printed23    
    Emailed0    
    PDF Downloaded67    
    Comments [Add]    
    Cited by others 1    

Recommend this journal