再生障碍性贫血病因学的新探索:异常免疫诱导骨髓间充质干细胞的过度脂肪化(英文)

A novel etiology of aplastic anemia:the uncontrolled adipogenic differentiation of mesenchymal stem cells in bone marrow induced by an abnormal immunological reaction

再生障碍性贫血(简称再障)是一种以血细胞减少为表现的疾病。骨髓脂肪过多且造血前体细胞减少是其显著骨髓病理学特征。本文解读和分析了与再障和脂肪细胞相关的论著和关键综述,旨在对骨髓脂肪细胞在再障发病中的作用进行初步探索。这些文献提示,再障相关性毒素和毒性药物,一般也具有诱导骨髓间充质干细胞向脂肪细胞分化的作用。再障的免疫治疗反应时间要远远长于典型免疫相关性血细胞减少症,表明异常免疫的靶细胞不仅仅是造血干/祖细胞,骨髓间充质干细胞也可能也受累。免疫抑制剂和雄激素治疗再障有效,二者也具有抑制骨髓间充质干细胞向脂肪细胞分化的作用。脂肪细胞分泌的很多细胞因子均有抑制骨髓造血作用,包括肿瘤坏死因子(TNF-α),白细胞介素6(IL-6)和干扰素γ(IFN-γ)。动物模型也证实,骨髓过度脂肪化可抑制造血。另外,获得性再生障碍性贫血一般被视作一种免疫介导的疾病,包括免疫细胞和分子介导造血干/祖细胞破坏导致骨髓造血衰竭。综上,骨髓内间充质干细胞向脂肪细胞过度分化可能是再障发病的新的病理学机制之一。

Aplastic anemia （AA） is a clinical syndrome manifested by cytopenia and the fatty replacement of the marrow with a near absence of hematopoietic precursor ceils. The present review explored the pathological roles of adipocytes in AA. The original articles and critical reviews selected were relevant to aplastic anemia, mesenchymal stem ceils and adipocytes. The following well-documented evidence demonstrates that over adipogenesis has negative effects on aplastic anemia. 1） Increasing evidence indicates that toxins and toxic drugs that can frequently lead to AA can concomitantly induce mesenchymal stem cells （MSCs） to undergo adipogenesis. 2） The response time of immunosuppressive therapy for AA is significantly longer than that of other immuno-related cytopenia disorders, such as immune thrombocytopenia, indicating that not only hematopoietic cells but also possibly MSCs are targeted by abnormal immune status in AA patients. 3） Both the immunosuppressive and androgen therapies used for AA can decrease the adipogenesis of MSCs in the marrow. 4） A number of myelosuppressive cytokines, including tumor necrosis factor （TNF-a）, interleukin 6 （IL-6） and interferon （IFN-y ）, can be produced by adipose tissue. Exorbitant adipogenesis can directly inhibit hematopoiesis in animal models. This novel etiological model is worthy of further corroboration via experiments. If this finding is valid, the therapeutic modality would undoubtedly shift from immune suppression to the combination of immune suppression and the interference of the pathway involved in the adipogenesis of MSCs. The findings suggest the uncontrolled adipogenic differentiation of mesenchymal stem ceils in bone marrow induced by an abnormal immunological reaction, which is a novel etiology of aplastic anemia.