The present study was designed to test the concept that platelets release a humoral factor that plays a regulatory role in megakaryopoiesis. The results showed that, among various hematoregulatory cytokines examined, transforming growth factor-β1 (TGF-β1) was by far the most potent enhancer of mRNA expression of bone marrow stromal thrombopoietin (TPO), a commitment of lineage specificity. The TPO, in turn, induced TGF-β receptors I and II on megakaryoblasts at the midmegakaryopoietic stage; at this stage, TGF-β1 was able to arrest the maturation of megakaryocyte colony-forming units (CFU-Meg). This effect was relatively specific when compared with its effect on burst-forming unit-erythroid (BFU-E) or colony-forming unit–granulocyte-macrophage (CFU-GM). In patients with idiopathic thrombocytopenic purpura (ITP), the levels of both TGF-β1 and stromal TPO mRNA were correlatively increased and an arrest of megakaryocyte maturation was observed. These in vivo findings are in accord with the aforementioned in vitro results. Thus, the results of the present investigation suggest that TGF-β1 is one of the pathophysiological feedback regulators of megakaryopoiesis.
Central venous catheter-related blood stream infections (CR-BSIs) are a serious complication in patients with hematological malignancies. However, it remains unclear whether there is a difference in the rate of CR-BSI associated with the conventional type of central venous catheters (cCVCs) and peripherally inserted CVCs (PICCs) in such patients. To address this question, we retrospectively investigated the incidence of CR-BSIs associated with PICCs versus cCVCs in patients with hematological malignancies. We used PICCs in all consecutive patients requiring CVC placement between February 2009 and February 2013. We compared the CR-BSI rate in patients with PICCs with that in patients with cCVCs treated between September 2006 and January 2009 (control group). Eighty-four patients received PICCs and 85 received cCVCs. The most common reason for removal due to catheter-related complications was CR-BSI. The CR-BSI rate in the PICC group was significantly lower than that in the cCVC group (PICCs: 1.23/1000 catheter days; cCVCs: 5.30/1000 catheter days; P < 0.01). Catheter-related complications other than CR-BSIs occurred at an extremely low rate in the PICC group. The median catheter-related complication-free survival duration was significantly longer in the PICC group than in the cCVC group. Our study shows that PICCs are useful in patients with hematological malignancies.
Acute graft-versus-host diseases (GVHD) is a major cause of morbidity and mortality in patients undergoing allogeneic bone marrow transplantation (BMT). T helper 1 (Th1)-type cytokines such as interferon-gamma or tumor necrosis factor-alpha have been implicated in the pathogenesis of acute GVHD. TAK-603 is a new quinoline derivative, which is now in clinical trials for use as a disease-modifying antirheumatic drug. In preclinical studies, it inhibited delayed-type hypersensitivity, but not Arthus-type reaction, in mice, and selectively suppressed Th1 cytokine production. Thus, the present study was designed to investigate whether the Th1 inhibitor (TAK-603) ameliorates lethal acute GVHD in a mouse model. Administration of TAK-603 into BALB/c mice given 10 Gy total body irradiation followed by transplantation of bone marrow and spleen cells from C57BL/6 mice markedly reduced the mortality in association with minimal signs of GVHD pathology in the liver, intestine, and skin. TAK-603 reduced not only the production of Th1-type cytokines, but also the proportion of Th1 cells in CD4(+) helper T cells in this GVHD mouse model. These results suggest that TAK-603 could be a potent therapeutic agent for acute lethal GVHD.
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