Mingfeng Zhao

Free iron catalyzes oxidative damage to hematopoietic cells/mesenchymal stem cells in vitro and suppresses hematopoiesis in iron overload patients.

Transfusional iron overload is of major concern in hematological disease. Iron‐overload‐related dyserythropoiesis and reactive oxygen species (ROS)‐related damage to hematopoietic stem cell (HSC) function are major setbacks in treatment for such disorders. We therefore aim to investigate the effect of iron overload on hematopoiesis in the patients and explore the role of ROS in iron‐induced oxidative damage in hematopoietic cells and microenvironment in vitro.

ROS-mediated iron overload injures the hematopoiesis of bone marrow by damaging hematopoietic stem/progenitor cells in mice

Iron overload, caused by hereditary hemochromatosis or repeated blood transfusions in some diseases, such as beta thalassemia, bone marrow failure and myelodysplastic syndrome, can significantly induce injured bone marrow (BM) function as well as parenchyma organ dysfunctions. However, the effect of iron overload and its mechanism remain elusive. In this study, we investigated the effects of iron overload on the hematopoietic stem and progenitor cells (HSPCs) from a mouse model. Our results showed that iron overload markedly decreased the ratio and clonogenic function of murine HSPCs by the elevation of reactive oxygen species (ROS). This finding is supported by the results of NAC or DFX treatment, which reduced ROS level by inhibiting NOX4 and p38MAPK and improved the long-term and multi-lineage engrafment of iron overload HSCs after transplantation. Therefore, all of these data demonstrate that iron overload injures the hematopoiesis of BM by enhancing ROS through NOX4 and p38MAPK. This will be helpful for the treatment of iron overload in patients with hematopoietic dysfunction.

Multiple Cytotoxic Factors Involved in IL-21 Enhanced Antitumor Function of CIK Cells Signaled through STAT-3 and STAT5b Pathways

BACKGROUND/OBJECTIVES Maintenance of cellular function in culture is vital for transfer and development following adoptive immunotherapy. Dual properties of IL-21 in activating T cells and reducing activation induced cell death led us to explore the mechanism of action of IL-21 enhanced proliferation and cytotoxic potential of CIK cells. METHOD CIK cells cultured from PBMCs of healthy subjects were stimulated with IL-21 and cellular viability and cytotoxicity to K562 cells were measured. To elucidate the mechanism of action of IL-21, mRNA expression of cytotoxic factors was assessed by RT-PCR and protein expression of significantly important cytotoxic factors and cytokine secretion were determined through flow cytometry and ELISA. Western blotting was performed to check the involvement of the JAK/STAT pathway following stimulation. RESULTS We found that IL-21 did not enhance in vitro proliferation of CIK cells, but did increase the number of cells expressing the CD3+/ CD56+ phenotype. Cytotoxic potential was increased with corresponding increase in perforin (0.9831±0.1265 to 0.7592±0.1457), granzyme B (0.4084±0.1589 to 0.7319±0.1639) and FasL (0.4015±0.2842 to 0.7381±0.2568). Interferon gamma and TNF-alpha were noted to increase (25.8±6.1 ng/L to 56.0±2.3 ng/L; and 5.64±0.61 μg/L to 15.14±0.93 μg/L, respectively) while no significant differences were observed in the expression of granzyme A, TNF-alpha and NKG2D, and NKG2D. We further affirmed that IL-21 signals through the STAT-3 and STAT- 5b signaling pathway in the CIK cell pool. CONCLUSION IL-21 enhances cytotoxic potential of CIK cells through increasing expression of perforin, granzyme B, IFN-gamma and TNF-alpha. The effect is brought about by the activation of STAT-3 and STAT-5b proteins.

Empirical antifungal treatment for diagnosed and undiagnosed invasive fungal disease in patients with hematologic malignancies

Abstract Background: Empirical antifungal therapy is effective in some patients with risk factors for invasive fungal disease (IFD) who do not qualify for the EORTC/MSG criteria for IFD, but who fail to respond to anti-bacterial and anti-viral therapy. Objective: This retrospective single-center study investigated the epidemiology of IFD and empirical antifungal therapy in patients with hematological malignancies. Methods: This study recruited 893 patients with hematologic malignancies who had failed to respond to anti-bacterial and anti-viral treatment and received antifungal therapy, but not for antifungal prophylaxis. Antifungal therapy regimens included amphotericin B, voriconazole, itraconazole and caspofungin. A total of 689 patients were diagnosed with proven, probable, or possible IFD, while 159 patients did not meet the EORTC/MSG criteria for IFD diagnosis but recovered with antifungal treatment, and 45 were excluded from having IFD. Effective treatment was defined as the disappearance or resolution of clinical symptoms of IFD. Results: Patients diagnosed with IFD underwent chemotherapy at a higher proportion, and had significantly higher neutrophil counts compared to those who did not qualify for the EORTC/MSG criteria for IFD but responded to antifungals. The mortality due to all causes within 3 months was significantly higher for patients diagnosed with proven IFD, compared with those who did not qualify for the EORTC/MSG criteria for IFD. There was no discontinuation reported due to adverse events of caspofungin. Conclusion: Empirical antifungal treatment could help save the lives of some patients with severe infections who are strongly suspected of having IFD.