Parsch Dominik, Brümmendorf Tim H, Richter Wiltrud, Fellenberg Jörg
University of Heidelberg, Heidelberg, Germany.
Arthritis Rheum. 2002 Nov;46(11):2911-6. doi: 10.1002/art.10626.
To investigate the contribution of clinical ex vivo expansion protocols to replicative aging of human chondrocytes.
Primary human chondrocytes were cultured as monolayers after isolation from 7 articular cartilage specimens. Cells were passaged corresponding to 12-19 cell population doublings (cpd). Aliquots of the cells were collected from each passage and analyzed for telomere length and telomerase activity.
The rate of telomere shortening was heterogeneous, ranging from 147 to 431 bp/cpd (mean +/- SD 305 +/- 122). Telomerase activity was detected at various time points during passaging in 5 of 7 primary chondrocytes analyzed, but not in native human articular cartilage specimens. According to our data, an 8-10-fold ( approximately 3 cpd) ex vivo expansion of articular chondrocytes, as typically performed for transplantation procedures, leads to telomere erosion in the range of 900 bp. This is comparable with 30 years of aging based on the in vivo rate of telomere shortening of 30 bp/year recently found in chondrocytes.
If telomere shortening is an important determinant of aging in human articular cartilage, an additional telomere loss due to ex vivo expansion might affect the incidence or time of onset of age-related cartilage disorders. However, given the limited extent of expansion performed in the clinical setting to date, a significant telomere-mediated increase in the risk of malignant transformation or replicative exhaustion of the transplanted cells seems unlikely.
研究临床体外扩增方案对人软骨细胞复制性衰老的影响。
从7个关节软骨标本中分离出原代人软骨细胞，将其作为单层细胞进行培养。细胞传代至相当于12 - 19个细胞群体倍增（cpd）。从每次传代中收集细胞 aliquots，并分析其端粒长度和端粒酶活性。
端粒缩短速率存在异质性，范围为147至431 bp/cpd（平均值±标准差 305±122）。在分析的7个原代软骨细胞中的5个传代过程中的不同时间点检测到端粒酶活性，但在天然人关节软骨标本中未检测到。根据我们的数据，关节软骨细胞进行8 - 10倍（约3 cpd）的体外扩增（这是移植手术中通常进行的）会导致端粒侵蚀达900 bp左右。这与基于最近在软骨细胞中发现的每年30 bp的体内端粒缩短速率计算得出的30年衰老相当。
如果端粒缩短是人类关节软骨衰老的一个重要决定因素，那么由于体外扩增导致的额外端粒丢失可能会影响与年龄相关的软骨疾病的发生率或发病时间。然而，鉴于迄今为止临床环境中进行的扩增程度有限，移植细胞发生恶性转化风险或复制性耗竭因端粒介导而显著增加的可能性似乎不大。
