Lu Xiaomei, Proctor Steve J, Dickinson Anne M
Haematological Sciences, School of Clinical & Laboratory Sciences, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
Cell Transplant. 2008;17(12):1423-8. doi: 10.3727/096368908787648155.
Endothelial progenitor cells (EPCs) has been shown to be present in umbilical cord blood (UCB) in addition to hematopoietic stem cells. Cryopreservation is the accepted method for long-term storage of UCB. However, whether EPCs can be derived from cryopreserved UCB samples is unclear. The aim of this study was to investigate the differentiation potential of EPCs from cryopreserved CB samples. CD34+ cells were isolated from fresh or frozen and thawed UCB using magnetic beads. Cells were then cultured on fibronectin-coated plates containing endothelial differentiation medium. After 4-5 weeks in culture, endothelial-like cells were generated from fresh UCB samples, but not cryopreserved UCB samples. Examining this further, both fresh and frozen/thawed UCB MNCs were stained with Annexin V-PE and 7-actinomycin D (7-AAD) using flow cytometry. We found that there were a significant number of apoptotic cells in cryopreserved UCB samples compared to fresh UCB samples. In conclusion, cryopreservation induced UCB cell apoptosis and impaired EPC differentiation.
除造血干细胞外，内皮祖细胞（EPCs）已被证明存在于脐带血（UCB）中。冷冻保存是脐带血长期储存的公认方法。然而，尚不清楚能否从冷冻保存的脐带血样本中获得内皮祖细胞。本研究的目的是调查冷冻保存的脐带血样本中内皮祖细胞的分化潜能。使用磁珠从新鲜或冷冻解冻的脐带血中分离出CD34+细胞。然后将细胞接种在含有内皮分化培养基的纤连蛋白包被的培养板上。培养4-5周后，新鲜脐带血样本产生了内皮样细胞，但冷冻保存的脐带血样本未产生。进一步研究发现，使用流式细胞术对新鲜和冷冻/解冻的脐带血单个核细胞（MNCs）进行膜联蛋白V-PE和7-放线菌素D（7-AAD）染色。我们发现，与新鲜脐带血样本相比，冷冻保存的脐带血样本中有大量凋亡细胞。总之，冷冻保存诱导脐带血细胞凋亡并损害内皮祖细胞分化。
