Biomedical subjects

Ken Toba

Publications and source records attributed to Ken Toba.

At least 19 recordsLinked to original sources

PubMed2006

Hydrodynamic-based delivery of an interleukin-22-Ig fusion gene ameliorates experimental autoimmune myocarditis in rats.

IL-22 is one of several cytokines with limited homology to IL-10. However, the biological activities of IL-22 are mostly unknown. The purpose of this study was to evaluate the effect of IL-22 on rat experimental autoimmune myocarditis (EAM) and elucidate an aspect of the biological activities of IL-22. Rats were immunized on day 0; IL-22-Ig-treated rats were injected with pCAGGS-IL-22-Ig and control rats with pCAGGS-Ig using hydrodynamics-based gene delivery on day 1 or day 6. IL-22-Ig gene therapy administered on day 1 or day 6 after immunization was effective in controlling EAM as monitored by the heart weight to body weight ratio, and the myocarditis area in rats was sacrificed on day 17. Examination of the expression of IL-22-related genes in purified cells from EAM hearts suggested that IL-22-Ig acting target cells were noncardiomyocytic (NC) noninflammatory cells such as fibroblasts, smooth muscle cells, and endothelial cells. Therefore, we examined the effect of rIL-22 or serum containing IL-22-Ig on the expression of immune-relevant genes in IL-1-stimulated NC cells cultured from EAM hearts. Results showed that the expression of immunologic molecules (PGE synthase, cyclooxygenase-2, MIP-2, MCP-1, IL-6, and cytokine-induced neutrophil chemoattractant-2) in IL-1-stimulated NC cells was significantly decreased by rIL-22 or serum containing IL-22-Ig. EAM was suppressed by hydrodynamics-based delivery of plasmid DNA encoding IL-22-Ig, and the reason for this effectiveness may be that IL-22 suppressed gene expression of PG synthases, IL-6, and chemokines in activated NC noninflammatory cells.

Animals↗

PubMed2006

Cardioprotective effects of recombinant human erythropoietin in rats with experimental autoimmune myocarditis.

Erythropoietin (EPO) has been known to have cytoprotective effects on several types of tissues, presumably through modulation of apoptosis and inflammation. The effect of EPO on myocardial inflammation, however, has not yet been clarified. We investigated the cardioprotective effects of EPO in rats with experimental autoimmune myocarditis (EAM). Seven-week-old Lewis rats immunized with cardiac myosin were treated either with EPO or vehicle and were examined on day 22. EPO attenuated the functional and histological severity of EAM along with suppression of mRNAs of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 in the hearts as well as a reduction of apoptotic cardiomyocytes. The EPO receptor (EPO-R) was upregulated in the myocardium of EAM compared with that of healthy rats. These results may suggest that EPO ameliorated the progression of EAM by modulating myocardial inflammation and apoptosis.

Animals↗

PubMed2006

Erythroid cells play essential roles in angiogenesis by bone marrow cell implantation.

Bone marrow cell implantation (BMI) has been utilized to treat patients with limb and heart ischemia. BMI provides angiogenic precursors and angiogenic cytokine-producing cells, especially erythroid cells. In this study, we induced in vitro angiogenesis cultures and in vivo BMI simulation using a murine limb ischemia model to examine the role of erythroid cells and the effect of erythropoietin (EPO). Human erythroid colonies (BFU-e) induced capillary networks around the colonies in vitro. Erythroid cells in human bone marrow produced vascular endothelial growth factor and placental growth factor. The angiogenic effects of erythroid cells were further amplified in the presence of EPO. Limb-ischemic mice were treated with BMI +/- EPO, and limb survival, blood flow recovery, and muscle histology were analyzed. Treatment with whole bone marrow cells + EPO significantly improved limb survival and blood flow. The cumulative effects of EPO on BMI induced and increase in capillary number and artery enlargement. Erythroid cells were essential for the in vivo effects of BMI, and CD14-positive cells supported the biological effects. In addition to the direct effect of EPO on angiogenesis, EPO showed indirect effect on angiogenesis through amplifying the angiogenic effects by erythroid cells supported by CD14-positive cells.

Adult↗

PubMed2005

Expression of immunological molecules by cardiomyocytes and inflammatory and interstitial cells in rat autoimmune myocarditis.

BACKGROUND: In a heart with myocarditis, there are cardiomyocytes, inflammatory cells, and non-inflammatory interstitial cells. Immunological molecules are thought to influence not only inflammatory cells but also cardiac function and remodeling. Whatever their origin, the cells they target and the intercellular crosstalk they mediate remain unclear. Here, we examined native gene expression of immunological molecules in normal and rat experimental autoimmune myocarditis (EAM) 18 and 90 days after immunization, using real time RT-PCR in cardiomyocytes, CD11b(+) cells, alphabetaT cells and non-cardiomyocytic non-inflammatory (NCNI) cells. METHODS AND RESULTS: Cells were isolated by collagenase perfusion on a Langendorff apparatus and purified by passing through a stainless-steel sieve followed by magnetic bead column separation using appropriate monoclonal antibodies. Most immunological molecules were expressed in inflammatory cells. However, some were expressed in NCNI cells or cardiomyocytes. Interestingly, most of interleukin (IL)-10, monocyte chemoattractant protein (MCP)-1, or tumor necrosis factor (TNF)-alpha receptor were found in NCNI cells and most of fractalkine were found in NCNI cells and cardiomyocytes. Moreover, TNF-alpha significantly upregulated fractalkine and MCP-1 mRNA in cultivated cells from EAM hearts. CONCLUSION: In the rat experimental myocarditis heart, inflammatory cells express many immunological molecules. Some of them are thought to influence NCNI cells or cardiomyocytes directly via receptors on these cell types. It is further suggested that fractalkine, IL-10, and MCP-1 expressed in NCNI cells or cardiomyocytes regulate inflammatory cells.

Animals↗

PubMed2005

Effect of hydrodynamics-based gene delivery of plasmid DNA encoding interleukin-1 receptor antagonist-Ig for treatment of rat autoimmune myocarditis: possible mechanism for lymphocytes and noncardiac cells.

BACKGROUND: Interleukin-1 (IL-1) is a powerful and important cytokine in myocarditis. The purpose of this study was to evaluate the effect and possible mechanism of hydrodynamics-based delivery of the IL-1 receptor antagonist (IL-1RA)-immunoglobulin (Ig) gene for treatment of rat experimental autoimmune myocarditis (EAM). METHODS AND RESULTS: On the day after immunization, rats were transfected with either pCAGGS encoding IL-1RA-Ig or pCAGGS encoding Ig alone. On day 17, IL-1RA-Ig gene therapy was effective in controlling EAM, as monitored by a decreased ratio of heart weight to body weight, reduced myocarditis areas, reduced gene expression of atrial natriuretic peptide in hearts, and improved cardiac function in echocardiographic and hemodynamic parameters. Examination of the expression of IL-1-related genes in purified cells from EAM hearts suggested that ectopic IL-1RA-Ig-acting target cells were alphabetaT cells and noncardiomyocytic noninflammatory cells such as fibroblasts, smooth muscle cells, and endothelial cells. Therefore, we examined the effect of serum containing IL-1RA-Ig on the expression of immune-relevant genes within noncardiomyocytic cells cultured from EAM hearts or concanavalin A-stimulated lymphocytes derived from lymph nodes in EAM-affected rats. The expression of immunologic molecules (prostaglandin E synthase, cyclooxygenase-2, and IL-1beta) in cultivated noncardiomyocytic cells and Th1 cytokines (IL-2 and IFN-gamma) in lymphocytes was significantly decreased by the serum containing IL-1RA-Ig. CONCLUSIONS: EAM was suppressed by hydrodynamics-based delivery of plasmid DNA encoding IL-1RA-Ig. In addition, IL-1RA-Ig suppressed gene expression of prostaglandin synthases and IL-1 in noncardiomyocytic cells and Th1 cytokines in lymphocytes.

Animals↗

PubMed2005

Persistence of various chromosomal aberrations in recipient cells during complete remission after bone marrow transplantation followed by graft rejection.

A 16-year-old boy in a second remission of acute lymphoblastic leukemia (ALL) had undergone transplantation of bone marrow from an unrelated donor. The conditioning regimen consisted of high-dose cytarabine, etoposide and 12 Gy of total-body irradiation. Although the donor marrow was rejected, hematopoiesis by the recipient himself recovered and he has remained in complete remission for more than 8 years after stem cell transplantation (SCT). Bone marrow karyotype analysis 1 month after SCT showed random chromosomal aberrations. Although complete remission was maintained, various chromosomal aberrations were detected in marrow cells, and in peripheral blood cells under phytohemagglutinin stimulation over 8 years. Moreover, a clone including del(20)(q11) appeared in marrow cells 7 months after SCT and thereafter was also detected 5 years later in the peripheral blood. This persistence of various chromosomal aberrations and a stable clone without evolution to myelodysplastic syndrome or leukemia support the multi step theory of leukemogenesis.

Adolescent↗

PubMed2005

The effect of hydrodynamics-based delivery of an IL-13-Ig fusion gene for experimental autoimmune myocarditis in rats and its possible mechanism.

Interleukin (IL)-13 is a pleiotropic cytokine secreted by activated Th2 T lymphocytes. Th1 cytokines are assumed to exacerbate and Th2 cytokines to ameliorate rat experimental autoimmune myocarditis (EAM). Here, we examined the effect of IL-13 on EAM, using a hydrodynamics-based delivery of an IL-13-Ig fusion gene, as well as the possible mechanism of its effect. Rats were immunized on day 0, and IL-13-Ig-treated rats were injected with pCAGGS-IL-13-Ig, and control rats with pCAGGS-Ig, on day 1 or 7. On day 17, the IL-13-Ig gene therapy was effective in controlling EAM as monitored by a decreased heart weight/body weight ratio, by reduced myocarditis and by reduced atrial natriuretic peptide mRNA in the heart, as a heart failure marker. On the basis of IL-13 receptor mRNA expression in separated cells from EAM hearts, we proposed that IL-13-Ig target cells were CD11b(+) cells and non-cardiomyocytic noninflammatory (NCNI) cells, such as fibroblasts, smooth muscle or endothelial cells. IL-13-Ig inhibited expression of the genes for prostaglandin E synthase, cyclooxygenase-2, inducible nitric oxide synthase, IL-1beta and TNF-alpha in cultivated cells from EAM hearts, while it enhanced expression of the IL-1 receptor antagonist gene. We conclude that IL-13-Ig ameliorates EAM and suppose that its effectiveness may be due to the influence on these immunologic molecules in CD11b(+) and NCNI cells.

Animals↗

PubMed2005

In vitro effect of cyclosporin A, mitomycin C and prednisolone on cell kinetics in cultured human umbilical vein endothelial cells.

INTRODUCTION: Vascular endothelial cell damage plays an important role in microvascular thrombogenesis. In vivo administration of cyclosporin A or mitomycin C sometimes results in thrombotic microangiopathy in patients. MATERIALS AND METHODS: The effects of cyclosporin A, mitomycin C and/or prednisolone on the cell cycle in cultured human umbilical vein endothelial cells were investigated to evaluate drug-induced endothelial cell damage and the protective effect of prednisolone on endothelial cells against the damage by cyclosporin A or mitomycin C in vitro. RESULTS: The addition of cyclosporin A to cultures caused proliferation arrest in the G1-phase in a dose-dependent manner, while mitomycin C inhibited DNA synthesis, which resulted in cell cycle arrest and inhibition of BrdUrd incorporation in the S-phase. The administration of prednisolone also caused cell cycle arrest in the G1 by itself, and protected the cells from the damage caused by mitomycin C. The inhibitory effects of cyclosporin A and prednisolone on the cell cycle were reversible, while mitomycin C was not. The highly phosphorylated retinoblastoma protein expressed in human umbilical vein endothelial cells decreased in the presence of mitomycin C. Soluble thrombomodulin levels in the culture supernatant were elevated by the addition of cyclosporin A. CONCLUSION: These effects of the drugs may cause the cell cycle arrest and the prolonged repair of damaged endothelial cells in patients.

Blotting, Western↗

PubMed2004

Sensitive measurement of fragmented red cell population using flow cytometry, and its application for estimating thrombotic microangiopathy after stem cell transplantation.

BACKGROUND: Thrombotic microangiopathy (TMA) is one of the lethal complications after hematopoietic stem cell transplantation (SCT). The levels of fragmented red cells (FRCs), thrombomodulin (TM), and factor VIII-related antigen in the blood are the most important markers for estimating TMA. However, the FRC level has been measured by using microscopy and the naked eye; therefore, an improvement in technology to objectively count FRC is necessary. METHODS: We established a novel technique to sensitively measure FRC as glycophorin A dull-positive small particles using a flow cytometer and estimated its reliability in patients treated with SCT. The blood level of FRC was compared with other clinical data in 257 blood samples in 16 clinical courses after SCT of 15 patients. RESULTS: Sorted glycophorin A dull-positive small particles morphologically showed FRC. Measured FRC percentage had a weak correlation with serum levels of lactate dehydrogenase (LDH) and total bilirubin but not with TM level, whereas TM showed a weak correlation with the levels of aspartate aminotransferase and LDH. In a patient with fulminant TMA, decrement of the FRC level led to improvement in liver parameters after treatment, presumably due to the rapid clearance of FRC, and increased simultaneously with the levels of LDH and bilirubin by the TMA recurrence. CONCLUSIONS: Levels of FRC percentage and TM were independent parameters of TMA. This novel technique may be used as a standard methodology in diagnosing TMA.

Adolescent↗

PubMed2004

Simultaneous expression of CD13, CD22 and CD25 is related to the expression of Fc epsilon R1 in non-lymphoid leukemia.

Like CD19 or CD56, CD22 in non-lymphoid leukemia has been considered an aberrantly expressed antigen. CD22 had been believed to be restricted to B lymphoid, however, it was also found to be expressed in human basophils. Mature basophils are unique granulocytes expressing CD13, CD22 and CD25. To estimate whether the expression of CD22 in non-lymphoid leukemia is aberrant or related to basophilic character, we analyzed 108 patients with primary and secondary leukemia. Among non-lymphoid leukemias, surface CD22 expression was more frequently observed in peroxidase-negative AML and secondary leukemia, and was usually observed simultaneously with CD13 and CD25. Samples obtained from 17 cases were further analyzed, and all the Fc epsilon R1-positive cases were observed in peroxidase-negative AML and secondary non-lymphoid leukemia, and mostly expressed CD13, CD22 and CD25. Therefore, surface CD22 expression in non-lymphoid leukemia was thought to relate to basophilic phenotype in some cases. Like CD22, some of the so-called aberrantly expressed antigens may not actually be aberrant, but are expressed in a stage of differentiation and maturation of progenitors. Moreover, CD22 may be one of target molecules for treatment of CD22-positive, poorly prognostic leukemia.

Adolescent↗

PubMed2004

Induction of T cell anergy by the treatment with IL-10-treated dendritic cells.

In order to apply for reducing graft versus host disease in allogeneic stem cell transplantation, the study concerning the induction of specific T cell anergy was designed. Normal allogeneic lymphocytes, which were co-cultured with IL-10-treated immature dendritic cells in the first mixed leukocyte culture (MLC), were cultured with mature dendritic cells of the same origin as IL-10-treated immature dendritic cells in the second MLC. By co-culturing with IL-10-treated immature dendritic cells, the response of normal lymphocytes to mature dendritic cells cultured from the same individual as that of IL-10-treated dendritic cells was markedly reduced, compared with the lymphocytes cultured with non-treated dendritic cells or IL-10-treated dendritic cells from a third party individual. The present study demonstrated that antigen specific T cell anergy was generated by priming allogeneic lymphocytes with IL-10-treated immature dendritic cells. These data suggested the applicability of IL-10-treated recipient dendritic cells for the induction of recipient cell-specific donor T cell anergy in donor graft.

Clonal Anergy↗

PubMed2004

Clinical application of bone marrow implantation in patients with arteriosclerosis obliterans, and the association between efficacy and the number of implanted bone marrow cells.

BACKGROUND: There have been a number of recent reports on the use of autologous bone marrow implantation (BMI) in the treatment of peripheral arterial disease, with a clinical response rate of approximately 70%. However, the factors that influence efficacy have not yet been clarified. We have analyzed the relationship between the number of implanted bone marrow cells and the clinical efficacy of BMI. METHODS AND RESULTS: Eight patients with arteriosclerosis obliterans were treated with BMI. Bone marrow was aspirated from the ilium (500-1,000 ml), the mononuclear cells were separated and then were implanted. The clinical effectiveness of BMI was evaluated by assessing changes in the ankle-brachial pressure index (ABI) and the transcutaneous oxygen pressure (TcO2) between the pre-treatment baseline, with follow-up testing at 4 weeks. These changes were defined as DeltaABI and DeltaTcO2. The mean number of CD34-positive cells was 1.04+/-0.60 x10(6) /kg body weight. There was a strong correlation between the number of CD34-positive cells and DeltaABI (r=0.754, p=0.028). CONCLUSIONS: It is likely that the number of implanted CD34-positive cells is one of the primary factors that influence the clinical efficacy of BMI.

Aged↗

PubMed2004

Human dendritic cells mediate anti-tumor activity against hematopoietic tumor cells without direct contact and Fas/FasL killing pathway.

During maturation, the capacity of dendritic cells (DCs) to uptake and process antigens becomes diminished while the expression of MHC molecules and costimulatory molecules is up-regulated. These phenotypic changes make DCs potent antigen presenting cells with the ability to initiate and modulate immune responses. Recent findings have shown that DCs can mediate direct cytotoxicity toward tumor cells. Here, we investigated the effect of monocyte derived DC (moDC) on hematopoietic tumor cells by assessing the uptake of [methyl-3H]thymidine (3H-TdR), JAM test (radiometric assay for DNA fragmentation) and 51Cr-release assay. We found that moDCs significantly inhibited the growth of 6 tumor cell lines and stimulated another 4 cell lines independently of the expression of Fas protein. MoDCs also inhibited the proliferation of tumor cells in transwell culture, including two cell lines that were driven to proliferate by direct contact with moDCs. Apoptosis, but not cytolysis, was detected in all the cell lines inhibited by moDCs. In contrast, no cytostatic or cytotoxic effect was detected on K562 cells (chronic myeloid leukemia) and BY94 cells (sporadic Burkitt's lymphoma). The inhibitory activity of moDCs on Fas-expressing tumor cells fully persisted after the neutralization of FasL. Accordingly, there was no detection of FasL protein or FasL mRNA expression in moDC. These results suggest that moDCs can mediate a direct anti-tumor activity against hematopoietic tumor cells through cytostasis in absence of contact or through apoptosis without triggering the Fas/FasL pathway.

Apoptosis↗

PubMed2003

The effects of STI571 on antigen presentation of dendritic cells generated from patients with chronic myelogenous leukemia.

Chronic myelogenous leukemia is caused by the acquisition of the reciprocal (9;22)(q34;q11) chromosomal translocation in hematopoietic stem cells. The fusion protein showed higher and aberrant tyrosine kinase activity. The inhibition of the tyrosine kinase activity of the protein represents a specific therapeutic strategy for bcr/abl-expressing leukemias. STI571 is a compound of the 2-phenylaminopyrimidine class that selectively inhibits the tyrosine kinase activity of the Abl protein tyrosine kinase. In this study, we evaluated the effects of STI571 on antigen presentation of dendritic cells generated from the patients with CML. The data showed that by the addition of STI571 the dendritic cells derived from CML clone showed an increased expression of CD1a, CD83, CD80 and CD86 by flow cytometry analysis and showed more intense abilities of allogeneic antigen presentation by mixed leukocyte culture, compared with the control cells without STI571. Our results suggested that STI571 not only has a direct cytotoxic effect on bcr-abl gene rearranged cells but also an indirect effect associated with increased anti-leukemic immunological function due to an intensified antigen presentation.

Antigen Presentation↗

PubMed2003

Fc epsilon RI and CD22 mRNA are expressed in early B-lineage and myeloid leukemia cell lines.

CD22, one of the important markers for diagnosing B-lineage acute leukemia, was expressed in mature basophil granulocytes. We then investigated the expression of CD22 and other B cell- and basophil-related molecules in 25 human acute leukemia cell lines to find the phenotype of the virtual common progenitor of B and myeloid lineage. Surface and cytoplasmic expressions of antigens were analyzed using a flow cytometer and an essential antibody panel used for diagnosing acute leukemia as well as cytokine receptors and basophil-related enzymes. Messenger RNA expression of Fc epsilon R1 and CD22 was also analyzed. Peroxidase-positive and -negative myeloid leukemias showed eosinophil- and basophil-type expression of enzymes, respectively. Early myeloid and B-lineage cells expressed basically similar combinations of cytokine receptors and various combinations of mRNA listed above, while T-lineage cells did not. The virtual common progenitor of B and myeloid lineage cells may be defined as immature cells simultaneously expressing B and basophil phenotypes.

Acute Disease↗

PubMed2003

Masked MLL gene rearrangement was disclosed in the clinical course and sequential development of chromosome abnormality in a patient with therapy related acute myelogenous leukemia.

Therapy related acute myelogenous leukemia in a 55-year-old Japanese woman is described. She had been treated for a diagnosis of non-Hodgkin's lymphoma 2 years before the onset of the secondary leukemia. She was diagnosed as AML (FAB: M2) with monosomy 7, and successfully treated by an intensive combination chemotherapy followed by an autologous peripheral blood stem cell transplantation. The disease relapsed shortly after the treatment, and the karyotype analysis revealed a complex abnormality accompanied with t(9;11)(p22;q23), however, monosomy 7 was absent. Southern blotting analysis was performed, and MLL rearrangement was evident in both the bone marrow samples obtained at that time and the cryopreserved marrow cells obtained at the onset of the disease. The bone marrow sample stored in a Carnoy solution at the onset was further analyzed, and three karyotype panels showing 45,XX, -7, t(9;11)(p22;q23) were found. Like this situation, a masked MLL rearrangement may have existed in some cases with hematopoietic malignancies, and appear to be disclosed in the clinical course.

Cell Transformation, Neoplastic↗

PubMed2003

Onset of hepatic erythropoiesis after malarial infection in mice.

Plasmodium yoelii-infected erythrocytes were injected into mice with or without 6.5 Gy irradiation. This irradiation suppressed erythropoiesis and induced severe immunosuppression. However, these mice showed a rather delayed infection, suggesting that fresh erythrocytes may become malarial targets. In other words, malarial infection did not persist without newly generated erythrocytes in mice. We then examined erythropoiesis in the liver and bone marrow of mice with malaria. Surprisingly, erythropoiesis began in the liver. At this time, the serum level of erythropoietin (EPO) was prominently elevated and the EPO mRNA also became detectable in the kidney. Many clusters of red blood cells appeared de novo in the parenchymal space of the liver. These results revealed that malarial infection had a potential to induce the onset of hepatic erythropoiesis in mice.

Animals↗

PubMed2003

Long-term production of pre-existing alloantibodies to E and c after allogenic BMT in a patient with aplastic anemia resulting in delayed hemolytic anemia.

BACKGROUND: Delayed hemolysis mediated by long-term production of pre-existing recipient-derived antibodies directed against donor RBC antigens after allogenic BMT is an unusual complication of hematopoietic transplantation. CASE REPORT: A 26-year-old man with aplastic anemia had pre-existing alloantibodies to E and c. He received BMT from a donor, whose Rh phenotype was E+, c+. From about 1 month after the transplant, he showed mild hemolysis due to the antibodies. RESULTS: The patient was typed as group B, CCDee and had anti-E and c alloantibodies before BMT. The donor was typed as group O, ccDEE. Although MNCs from the donor marrow were infused into the patient, DAT became positive on Day 21, and the patient-origin antibodies remained detectable by both DAT and IAT even 20 months after BMT. However, immunomagnetically isolated peripheral circulating B cells were 100 percent donor origin. The patient received prednisolone from Day 221, and thereafter, the signs of hemolysis disappeared. CONCLUSION: It is likely that the long-term production of alloantibodies is due to the existence of long-lived recipient plasma cells, which survive the conditioning regimen. This case suggests that patients with pre- existing alloantibodies that do not belong to the ABO system should be carefully followed up after BMT.

ABO Blood-Group System↗