The impact of low-dose busulfan on clonal dynamics in nonhuman primates
The impact of low-dose busulfan on clonal dynamics in nonhuman primates
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DOI：
10.1182/blood-2003-08-2935
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发表时间：
2004-09-01
期刊：
影响因子：
20.3
通讯作者：
Dunbar, CE
中科院分区：
文献类型：
--
作者：
Kuramoto, K;Follman, D;Dunbar, CE
了解个体多能造血干细胞（HSC）的数量和对血液谱系形成的贡献对于基因治疗和干细胞移植具有重要的临床意义。我们已经能够有效地标记恒河猴的长期再生干细胞和祖细胞与逆转录病毒载体，并跟踪其在体内的贡献造血使用线性扩增介导的聚合酶链反应（LAM-PCR）插入位点分析技术。我们评估了白消安对单个逆转录病毒标记克隆造血作用的影响。有2只猕猴在2年前接受了逆转录病毒转导的CD 34（+）细胞移植，然后用4 mg/kg白消安治疗。尽管外周血细胞计数仅受到短暂和轻度抑制，但有助于粒细胞产生的单个干细胞/祖细胞克隆的数量急剧减少，第一只猴子减少了80%，第二只猴子减少了60%。在对T细胞有贡献的克隆上也看到了类似的影响。第一只猴子在白消安给药后5个月，第二只猴子在3个月时，克隆数逐渐恢复到基线水平，并且在两只动物中保持稳定超过一年。用插入位点特异性引物跟踪单个克隆表明，在白消安之前有助于造血的克隆占这种恢复的大部分，但是一些以前未检测到的克隆在这个恢复阶段开始做出贡献。这些结果表明，即使是低剂量白消安显着影响干细胞和祖细胞的动力学。造血的克隆多样性显着下降后，即使是一个单一的，临床耐受性良好的关闭白消安，缓慢，但几乎完全恢复在接下来的几个月，这表明真正的长期再生干细胞没有永久删除。然而，许多克隆的长时间抑制表明，如果移植的HSC能够在这段时间内植入和增殖，则移植的HSC可能具有显著的竞争优势，并支持该药物在非清髓性方案中的使用（C）2004由美国血液学学会。
An understanding of the number and contribution of individual pluripotent hematopoietic stem cells (HSCs) to the formation of blood lineages has important clinical implications for gene therapy and stem cell transplantation. We have been able to efficiently mark rhesus macaque long-term repopulating stem and progenitor cells with retroviral vectors, and track their in vivo contributions to hematopoiesis using the linear amplification mediated-polymerase chain reaction (LAM-PCR) technique of insertion site analysis. We assessed the impact of busulfan on contributions of individual retrovirally marked clones to hematopoiesis. There were 2 macaques that received transplants of retrovirally transduced CD34(+) cells 2 years previously that were then treated with 4 mg/kg busulfan. Despite only transient and mild suppression of peripheral blood counts, the numbers of individual stem/progenitor clones contributing to granulocyte production decreased dramatically, by 80% in the first monkey and by 60% in the second monkey. A similar impact was seen on clones contributing to T cells. The clone numbers recovered gradually back toward baseline by 5 months following busulfan in the first monkey and by 3 months in the second monkey, and have remained stable for more than one year in both animals. Tracking of individual clones with insertion-site-specific primers suggested that clones contributing to hematopoiesis prior to busulfan accounted for the majority of this recovery, but that some previously undetected clones began to contribute during this recovery phase. These results indicate that even low-dose busulfan significantly affects stem and progenitor cell dynamics. The clonal diversity of hematopoiesis was significantly decreased after even a single, clinically well-tolerated close of busulfan, with slow but almost complete recovery over the next several months, suggesting that true long-term repopulating stem cells were not permanently deleted. However, the prolonged period of suppression of many clones suggests that transplanted HSCs may have a marked competitive advantage if they can engraft and proliferate during this time period, and supports the use of this agent in nonmyeloablative regimens (C) 2004 by The American Society of Hematology.