Martínez-Jaramillo G, Flores-Figueroa E, Gómez-Morales E, Sánchez-Valle E, Mayani H
Oncological Research Unit, Oncology Hospital, National Medical Center, IMSS, Mexico City, Mexico.
Am J Hematol. 2001 Nov;68(3):144-8. doi: 10.1002/ajh.1170.
We have previously shown that the levels of hematopoietic progenitors in long-term marrow cultures (LTMC) from patients with aplastic anemia (AA) are drastically reduced, as compared to normal LTMC. We have also reported that when LTMC from AA patients are supplemented with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) there is an increase in colony-forming cell (CFC) levels. However, such a stimulation is only transient and it is followed by an inhibition in CFC growth. Based on these observations, in the present study we have tested the hypothesis that the levels of tumor necrosis factor-alpha (TNF-alpha), an inhibitor of hematopoiesis, are increased in AA LTMC and that such levels are further increased after rhGM-CSF has been added to the cultures for several weeks. Accordingly, we have determined the levels of TNF-alpha in the supernatant of LTMC established from normal (n = 8) and AA (n = 6) bone marrow and in AA LTMC supplemented with rhGM-CSF (n = 6). At the time of culture initiation, TNF-alpha levels were below detection in all the samples analyzed. After 5 weeks of culture, TNF-alpha levels in normal LTMC were very low, with a median of 7.3 pg/mL. In contrast, AA LTMC contained higher levels of TNF-alpha (median of 49.6 pg/mL). In keeping with our hypothesis, addition of rhGM-CSF to AA LTMC resulted in a significant further increase of TNF-alpha levels (median of 135.4 pg/mL). Our results demonstrate an inverse correlation between reduced hematopoiesis in AA LTMC and increased levels of TNF-alpha in this culture system. Based on the results presented here, together with previous reports indicating that TNF-alpha is a potent inducer of apoptosis in hematopoietic progenitor cells, it seems reasonable to suggest that TNF-alpha is implicated in the pathophysiology of AA.
我们之前已经表明，与正常的长期骨髓培养物（LTMC）相比，再生障碍性贫血（AA）患者的长期骨髓培养物中造血祖细胞的水平大幅降低。我们还报告称，当给AA患者的LTMC补充重组人粒细胞 - 巨噬细胞集落刺激因子（rhGM - CSF）时，集落形成细胞（CFC）水平会增加。然而，这种刺激只是短暂的，随后CFC生长会受到抑制。基于这些观察结果，在本研究中我们测试了以下假设：造血抑制因子肿瘤坏死因子 - α（TNF - α）在AA LTMC中的水平升高，并且在向培养物中添加rhGM - CSF数周后，这种水平会进一步升高。因此，我们测定了从正常（n = 8）和AA（n = 6）骨髓建立的LTMC上清液以及补充了rhGM - CSF的AA LTMC（n = 6）中TNF - α的水平。在培养开始时，所有分析样本中的TNF - α水平均低于检测限。培养5周后，正常LTMC中的TNF - α水平非常低，中位数为7.3 pg/mL。相比之下，AA LTMC中TNF - α的水平更高（中位数为49.6 pg/mL）。与我们的假设一致，向AA LTMC中添加rhGM - CSF导致TNF - α水平显著进一步升高（中位数为135.4 pg/mL）。我们的结果表明，AA LTMC中造血减少与该培养系统中TNF - α水平升高之间存在负相关。基于此处呈现的结果，以及之前表明TNF - α是造血祖细胞凋亡的有效诱导剂的报告，认为TNF - α与AA的病理生理学有关似乎是合理的。
