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Susumu Ikehara

Publications and source records attributed to Susumu Ikehara.

At least 19 recordsLinked to original sources
PubMed2006

Effects of low-dose irradiation on enhancement of immunity by dendritic cells.

Low-doses of irradiation have been reported to have beneficial effects, particularly anti-tumor effects. In this paper, we show the effects of the low-dose irradiation on T cell activation induced by dendritic cells (DCs). DCs, which had been pre-irradiated at 0.02-1.0 Gy from a (137)Cs source, were cultured with allogeneic T cells, and the proliferation of T cells was then examined. The 0.05Gy-pre-irradiated DCs showed the highest proliferation capacity of T cells. The 0.05Gy-irradiation does not augment the expression of major histocompatibility complexes (MHCs) or costimulatory molecules on DCs, as with non-irradiated DCs or 1Gy-irradiated DCs, but does augment the production of IL-2, IL-12 and IFN-gamma DCs. These results suggest that the low-dose irradiation augments T cell-activation capacity through cytokine production by DCs, which might shift naïve helper T cells to Th1 cells.

Animals↗
PubMed2006

Isolation and characterization of hematopoietic progenitor cells in canine bone marrow.

For ultimate diagnoses of canine leukemia or malignant lymphoma, we sought to isolate hematopoietic progenitor cells (HPCs) from canine bone marrow (BM) using physiological phenotypes. Canine BM cells were separated by equilibrium discontinued density centrifugation, and HPCs, detected by in vitro colony formation, were significantly enriched in the relatively low density (LD) fraction. In flow cytometry, many CD34 or MHC class II expressing cells were detected in the LD fraction, but these were not significantly enriched. When the LD cells were separated, using a cell-sorting method, into cells with high affinity of wheat germ agglutinin (WGAhigh) and cells with WGAlow, almost all multipotent HPCs (MHPCs) and HPCs committed to myeloid lineage were found in the WGAhigh population. When the WGAhigh population was further stained for rhodamin 123, almost all MHPCs were included in the dull population (Rhlow), but not in the bright one (Rhhigh). Morphologically, most Rhlow cells were round, blastic cells containing a large nucleus with nucleoli and narrow cytoplasm. Based on these results, we suggest that all of the MHPCs in canine BM show the Rhlow WGAhigh LD phenotype, and may contain hematopoietic stem cells, which are the primitive HPCs.

Animals↗
PubMed2006

Transfer of accelerated presbycusis by transplantation of bone marrow cells from senescence-accelerated mice.

Until now, there has been no effective therapy for chronic sensorineural hearing impairment. This study investigated the role of bone marrow cells (BMCs) in cochlear dysfunction. BALB/c mice (2 months of age), a non-presbycusis-prone mouse strain, were lethally irradiated and then transplanted with BMCs from SAMP1 mice (2 months of age), a presbycusis-prone mouse strain. Acceleration of age-related hearing loss, early degeneration of spiral ganglion cells (SGCs) and impairment of immune function were observed in the recipient mice as well as in the SAMP1 mice. However, no spiral ganglion cells of donor (SAMP1) origin were detected in the recipient mice. These results indicated that accelerated presbycusis, cochlear pathology, and immune dysfunction of SAMP1 mice can be transferred to BALB/c recipient mice using allogeneic bone marrow transplantation (BMT). However, although the BMCs themselves cannot differentiate into the spiral ganglion cells (SGCs), they indirectly cause the degeneration of the SGCs. Further studies into the relationship between the inner ear cells and BMCs are required.

Aging↗
PubMed2006

Lin(-)CD34(-) bone marrow cells from adult mice can differentiate into neural-like cells.

Numerous studies have shown that some populations of bone marrow cells (BMCs) have the capacity to differentiate into neural cells, which is useful for repairing brain lesions. In this paper, we analyze neural differentiation features of lineage-negative/CD34-negative (Lin(-)CD34(-)) cells in the bone marrow of adult mice. The population of Lin(-)CD34(-) in BMCs was isolated by magnetic bead sorting and fluorescence-activated cell sorter (FACS) using specific lineage (CD4, CD8a, CD11b, CD45R, Gr-1 and TER-119) antibodies and CD34 antibody. First, we cultured Lin(-)CD34(-) BMCs in the presence of RNIF: vitamin A derivative retinoic acid (RA) and neural-inducing factors (platelet-derived growth factor BB (PDGF-BB), epidermal growth factor (EGF) and fibroblast growth factor-basic (FGF-b)). Analyses of RT-PCR and immunocytochemistry indicated that RNIF-treated Lin(-)CD34(-) BMCs expressed neural phenotypes as well as neurogenic transcription factors. When we implanted the Lin(-)CD34(-) BMCs isolated from enhanced green fluorescent protein (eGFP) transgenic mice into the subventricular zone (SVZ) of postnatal mice, eGFP-positive cells survived 3 weeks after the injection in the various brain regions, some of which expressed the neural phenotypes. Our data suggest that certain subsets in the CD34(-) populations of adult bone marrow could have the capacity to differentiate into neural cells in a suitable environment.

Animals↗
PubMed2006

The antioxidant role of a reagent, 2',7'-dichlorodihydrofluorescin diacetate, detecting reactive-oxygen species and blocking the induction of heme oxygenase-1 and preventing cytotoxicity.

Heme oxygenase-1 (HO-1) degrades heme into biliverdin, iron and CO. The enzyme participates in adaptive and protective responses to oxidative stress and various inflammatory stimuli, and is induced in response to reactive oxygen species (ROS). 2',7'-Dichlorodihydrofluorescin diacetate (DCFH-DA) is a common reagent used to detect ROS by the oxidation of 2',7'-dichlorodihydrofluorescin (DCFH) to fluorescent dichlorodihydrofluorescein. We previously found that rapid oxidation of DCFH occurred with heme-compounds as well as ROS [Ohashi, T. et al. (2002) FEBS Lett. 511, 21-27], and then examined the effect of DCFH-DA on the induction of HO-1 expression by arsenite, cadmium and hemin, which induce oxidative stress and cytotoxicity. We found suppression of the arsenite-, cadmium- and hemin-dependent induction of HO-1 with DCFH-DA. The suppression occurred at the transcriptional level since the promoter activity of the Maf-recognition site of the HO-1 gene decreased with the DCFH-DA treatment. DCFH abolished the phosphorylation of extracellular signal-regulated kinase, the nuclear translocation of a transcriptional activator Nrf2, and cell death. An antioxidant, N-acetylcysteine (NAC), also suppressed the induction by arsenite and cadmium, but not that by hemin, indicating that DCFH blocked a different site in the stress signal pathway from NAC. Considering that the oxidation of DCFH diminishes ROS generated by various stressors, our findings provide a potential strategy for protection of cells from toxic insults using DCFH-like molecules.

Acetylcysteine↗
PubMed2006

Generation of canine dendritic cells from peripheral blood monocytes without using purified cytokines.

Dendritic cells (DCs), which differentiate in vitro from peripheral blood monocytes (PBMOs) or bone marrow precursors, are a promising candidate for immunotherapy against cancer. The dog, which suffers common types of cancers along with humans, make an ideal large animal model for cancer studies. Monocyte-derived DCs in the dog have not been well characterized, however, since the appropriate condition for in vitro differentiation has not been established. To tackle this problem, we have developed a conditioned media by culturing T cells with immobilized anti-canine CD3 antibody, and sought to induce differentiation of DCs from PBMOs. When purified CD14+ PBMOs were cultured in the presence of 25% T cell conditioned medium (TCCM), the PBMOs increased size and had extended dendritic processes by day 12 of the culture. The cultured PBMOs were found to increase the expression of MHC class II and CD1a molecules, and significantly increased stimulatory activity for allogeneic T cells in the mixed leukocyte reaction. Moreover, the cells significantly increased their expression of IL-18 and IFN-gamma when stimulated with polyinosinic-polycytidylic acid (Poly (I:C)). The cells have a reduced phagocytic activity, which is a common defect in mature DCs. It follows from these results that TCCM does induce the differentiation of DCs from PBMOs.

Animals↗
PubMed2006

Treatment and transfer of emphysema by a new bone marrow transplantation method from normal mice to Tsk mice and vice versa.

We have recently established a new bone marrow transplantation (BMT) method in which bone marrow cells are injected into the intrabone marrow (IBM). In the present study, we used an animal model for emphysema (tight-skin [Tsk] mouse) to examine whether IBM-BMT could be used to treat emphysema in Tsk mice. IBM-BMT was carried out from C3H mice into Tsk mice (8-10 weeks old) that had already shown emphysema. Six months after transplantation, the lungs of all the Tsk mice treated with IBM-BMT [C3H-->Tsk] showed similar structures to those of normal mice, whereas the [Tsk-->Tsk] mice showed emphysema, as seen in age-matched Tsk mice. Next, we attempted to transfer emphysema from Tsk mice to C3H mice by IBM-BMT. Six months after IBM-BMT, the [Tsk-->C3H] mice showed emphysema. These results strongly suggest that emphysema in Tsk mice originates from defects of stem cells in the bone marrow.

Animals↗
PubMed2006

Mechanisms underlying acceleration of blood flow recovery in ischemic limbs by macrophage colony-stimulating factor.

Recently we reported that macrophage colony-stimulating factor (M-CSF) can mobilize endothelial progenitor cells (EPCs) from the bone marrow into the peripheral blood, resulting in an increase in the number of blood vessels and augmentation of blood flow in the ischemia-induced legs. M-CSF accelerates neovascularization of ischemic lesions resulting from the mobilization of EPCs. In the present paper, we analyze the mechanisms underling the mobilization of EPCs by M-CSF. M-CSF augments the production of vascular endothelial growth factor (VEGF) from the bone marrow cells, especially from myeloid lineage cells. In vivo administration of anti-VEGF antibody abrogates both the acceleration of the recovery of blood flow in the ischemia-induced limbs by M-CSF and the augmentation of the mobilization of EPCs induced by M-CSF. These results suggest that the M-CSF contributes to rapid recovery of blood flow in ischemic lesions by mobilization of EPCs from the bone marrow through augmentation of VEGF production in the bone marrow and that the VEGF is mainly produced by myeloid lineage cells.

Animals↗
PubMed2006

Establishment of animal models for three types of pancreatitis and analyses of regeneration mechanisms.

OBJECTIVES: To investigate the mechanisms underlying the onset and progress of pancreatitis, 3 animal models (chronic, acute, and severe pancreatitis) were established by double ligature of the pancreatic duct, injection with cerulein, or injection with cerulein + double ligature of the pancreatic duct. METHODS: We prepared a control and 3 experimental groups: group 1 (untreated control), group 2 (a chronic pancreatitis model; the pancreatic tail was exposed through a midline incision, and the pancreatic duct from this part was double-ligated), group 3 (an acute pancreatitis model; cerulein was intraperitoneally injected 7 times on day 0), and group 4 (a severe pancreatitis model; the double ligature of the pancreatic duct plus injection of cerulein). RESULTS: Kinetic observations of survival rate, relative pancreatic weight, and the macroscopical and microscopical diagnoses and observations of the changes in endocrine function clearly show that these 3 murine models of pancreatitis can serve as human models for chronic, acute, and severe pancreatitis. Furthermore, pancreas duodenum homeobox 1, cytokeratin 19, and Ki67 are expressed at the site of injury in the pancreas, resulting from the injection with cerulein and/or double ligature of the pancreatic ducts and indicating that there remains a tissue-regenerative capacity. CONCLUSIONS: These 3 mouse models could serve as human models for chronic, acute, and severe pancreatitis. Furthermore, cells of the epithelial lineage might participate in tissue regeneration in chronic, acute, and severe pancreatitis.

Amylases↗
PubMed2006

G-CSF and/or M-CSF accelerate differentiation of bone marrow cells into endothelial progenitor cells in vitro.

It has been reported that granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) can mobilize endothelial progenitor cells (EPCs) in bone marrow cells (BMCs) into peripheral blood (PB) in vivo. Previously, we also reported that macrophage-colony stimulating factor (M-CSF) can mobilize EPCs into PB, which results in the rapid recovery of blood flow in induced-ischemia limbs by augmenting the number of intramuscular capillaries in vivo. In the present study, we demonstrate that M-CSF and/or G-CSF can increase EPCs from lineage (CD3, B220, Gr-1, Mac-1, CD11c, Ter119, NK1.1 or CD31)-negative BMCs in vitro. Lineage-negative BMCs were cultured with or without M-CSF and/or G-CSF. Three days after culture with M-CSF and/or G-CSF, the number of Flk-1+/CD45-, Sca-1+/CD45-, CD31+/CD45- or CD146+/CD45- cells increased in comparison with no cytokines. When the cultured BMCs with or without G-CSF and/or M-CSF were intravenously injected into ischemia-induced hindlimbs of mice, the number of intramuscular capillaries in the ischemia-induced legs increased; BMCs cultured with G-CSF and/or M-CSF were more effective than those of cytokine non-treated BMCs. These results suggest that M-CSF and/or G-CSF can induce the differentiation of BMCs into EPCs, even in vitro.

Animals↗
PubMed2006

Synergistic effects of granulocyte-colony stimulating factor and macrophage-colony stimulating factor on recovery of donor hematopoietic cells in allogeneic bone marrow transplantation.

G-CSF and M-CSF are used clinically to augment hematopoiesis after bone marrow transplantation (BMT) and chemotherapy. In this paper, we examined the synergistic effect of G-CSF and M-CSF on hematopoietic recovery in allogeneic BMT as a model of human BMT. We performed BMT from eGFP-transgenic mice (C57BL/6 background; H-2b) into lethally-irradiated C3H (H-2k). From the day after BMT, G-CSF and/or M-CSF were injected for 5 consecutive days. Not only the numbers of day 12 CFU-S and spleen weight, but also white blood cell (WBC) counts in the peripheral blood (PB) and nuclear cells in the bone marrow (BM) increased in the mice treated with G-CSF and/or M-CSF 12 days after BMT. Moreover, the number of donor-type WBCs in the PB and donor-type nuclear cells in the BM also increased in the mice treated with G-CSF and/or M-CSF. The effects were pronounced when G-CSF and M-CSF were used together rather than independently. These results suggest that treatment with the combination of G-CSF and M-CSF has a synergistic effect on hematopoiesis in allogeneic BMT.

Animals↗
PubMed2005

Plasmacytoid dendritic cells of different origins have distinct characteristics and function: studies of lymphoid progenitors versus myeloid progenitors.

Plasmacytoid dendritic cells (pDCs) play a central role in host innate and adaptive immunity and are thought to be of lymphoid origin. However, in IL-7Ralpha-/- mice, which are deficient in T and B lymphocytes, pDCs are still found in lymphoid organs, which suggests that there is a lymphoid-independent pathway for the development of pDCs. Previous work has demonstrated that pDCs originate from both lymphoid and myeloid progenitors (MPs). However, it is not clear whether the function of pDCs is different relative to their origin. In an effort to compare the characteristics and functions between pDCs generated from different progenitors, we performed adoptive transfer studies using highly enriched populations of common lymphoid progenitors (CLPs) and MPs from the bone marrow of control mice and examined their potential and developmental kinetics for the generation of pDCs. Interestingly, although CLPs were polarized to generate pDCs, MPs were polarized to generate conventional dendritic cells and the kinetics of pDC generation from MPs was reached earlier than from CLPs. Furthermore, CLPs have the potential to generate more pDCs on a per cell basis. Moreover, MP-derived pDCs produce relatively higher levels of IFN-alpha than CLP-derived pDCs following CpG stimulation. These data indicate that MPs are multipotential and have the capacity to develop into not only myeloid cells, but also pDCs, which have distinct characteristics and function compared to that of lymphoid origin and, therefore, imply a more important role for MP-derived pDCs in conditions where the function of lymphoid progenitors is impaired or compromised.

Adoptive Transfer↗
PubMed2005

Characterization of mesenchymal stem cells isolated from mouse fetal bone marrow.

Mesenchymal stem cells (MSCs) are defined as cells that can differentiate into multiple mesenchymal lineage cells. MSCs have some features (surface molecules and cytokine production, etc.) common to so-called traditional bone marrow (BM) stromal cells, which have the capacity to support hemopoiesis. In the present study, we isolated murine MSCs (mMSCs) from the fetal BM using an anti-PA6 monoclonal antibody (mAb) that is specific for bone marrow stromal cells. The mMSCs, called FMS/PA6-P cells, are adherent, fibroblastic, and extensively expanded and have the ability to differentiate not only into osteoblasts and adipocytes but also into vascular endothelial cells. The FMS/PA6-P cells produce a broad spectrum of cytokines and growth factors closely related to hemopoiesis and show good hemopoiesis-supporting capacity both in vivo and in vitro, suggesting that they are a component of the hemopoietic stem cell niche in vivo. Interestingly, although the FMS/PA6-P cells express a high level of the PA6 molecule, which is reactive with anti-PA6 mAb, they gradually lose their ability to express this molecule during the course of differentiation into osteoblasts and adipocytes, indicating that the PA6 molecule might serve as a novel marker of mMSCs.

Adipocytes↗
PubMed2005

Long-term survival of bone marrow-derived retinal nerve cells in the retina.

Recently, we have demonstrated that bone marrow stem cells can differentiate into retinal nerve cells. In the present study, we show a new and efficient strategy for transplanting bone marrow stem cells into the retina. When bone marrow stem cells were injected into the vitreous cavity of untreated eyes, only very few cells were found in the retina 2 weeks after injection. In contrast, when laser photocoagulation was performed just before the injection of bone marrow stem cells, a large number of the injected cells survived 2 weeks after injection and the cells expressed neural cell-specific or retinal nerve cell-specific antigens. Moreover, we still detected bone marrow stem cell-derived retinal nerve cells in the retina 1 year after injection in the retina.

Analysis of Variance↗
PubMed2005

Appendix is a priming site in the development of ulcerative colitis.

AIM: The role of the appendix has been highlighted in the pathogenesis of ulcerative colitis (UC). The aims of this study were to elucidate the immuno-imbalances in the appendix of UC patients, and to clarify the role of the appendix in the development of UC. METHODS: Colonoscopic biopsy specimens of the appendix, transverse colon, and rectum were obtained from 86 patients with UC: active pancolitis (A-Pan; n = 15), active left-sided colitis (A-Lt; n = 25), A-Lt with appendiceal involvement (A-Lt/Ap; n = 10), inactive pancolitis (I-Pan; n = 14), and inactive left-sided colitis (I-Lt; n = 22), and from controls. In the isolated mucosal T cells, the CD4/CD8 ratio and proportion of activated CD4+ T cells were investigated, and compared with controls. RESULTS: In the appendix, the CD4/CD8 ratio significantly increased in A-Lt and A-Lt/Ap. The ratio in the appendix also tended to increase in A-Pan. In the rectum, the ratio significantly increased in all UC groups. In the appendix, the proportion of CD4+CD69+ (early activation antigen) T cells significantly increased in all UC groups. In the rectum, the proportion of CD4+CD69+ T cells significantly increased only in A-Pan. The proportion of CD4+HLA-DR+ (mature activation antigen) T cells significantly increased only in the rectum of A-Pan, but not in the other areas of any groups. CONCLUSION: The increased CD4/CD8 ratio and predominant infiltration of CD4+CD69+ T cells in the appendix suggest that the appendix is a priming site in the development of UC.

Adult↗
PubMed2005

Hepatocyte growth factor delivered by ultrasound-mediated destruction of microbubbles induces proliferation of cardiomyocytes and amelioration of left ventricular contractile function in Doxorubicin-induced cardiomyopathy.

At present, there is no curative strategy for advanced cardiomyopathy except for cardiac transplantation, which is not easily performed, mainly due to a shortage of donors. It has been reported that myocardial progenitor cells exist even in the postnatal heart, suggesting that myocardial progenitor cells could proliferate under some situations and might improve cardiac function in cardiomyopathy-induced hearts. In this study, recombinant human hepatocyte growth factor (rhHGF) was delivered using ultrasound-mediated destruction of microbubbles (UMDM) into the cardiomyopathy-induced heart by doxorubicin (20 mg/kg). Intravenous injection of rhHGF (IV-rhHGF) alone or UMDM alone failed to improve the morphology or the function of the cardiomyopathy-induced heart, but (IV-rhHGF + UMDM) treatment significantly improved the heart morphologically and functionally, and repetitive treatments of (IV-rhHGF + UMDM) enhanced the effects. The number of bromodeoxy-uridine-positive cardiomyocytes significantly increased in the (IV-rhHGF + UMDM)-treated hearts compared with the untreated hearts. Moreover, Sca-1+ myocardial progenitor cells express c-Met, a receptor for HGF. These results suggest that (IV-rhHGF + UMDM) treatment could morphologically and functionally improve the heart in the case of doxorubicin-induced cardiomyopathy through the proliferation of the myocardial progenitor cells.

Animals↗
PubMed2005

Treatment of senile osteoporosis in SAMP6 mice by intra-bone marrow injection of allogeneic bone marrow cells.

A substrain of the senescence-accelerated mouse, SAMP6 (senescence-accelerated mouse prone 6), spontaneously develops osteoporosis early in life. Therefore, this strain is a useful animal model for developing new strategies for the treatment of osteoporosis in humans. We succeeded in treating osteoporosis in SAMP6 mice after the onset of this disease, using a newly developed method of bone marrow transplantation (BMT): Allogeneic bone marrow cells obtained from normal mouse strains were directly injected into the bone marrow cavity of irradiated SAMP6 mice (intra-bone marrow BMT [IBM-BMT]). After the treatment with IBM-BMT, hematolymphoid cells were completely reconstituted by donor-derived cells, and bone marrow stromal cells were also found to be of donor origin. The treated SAMP6 mice showed histologically-normal trabecular bone. In addition, bone mineral density and urinary deoxypiridinoline, a hallmark of bone destruction, were normalized. When the message levels of cytokines (tumor necrosis factor alpha, interleukin-6 [IL-6], IL-11, and receptor activator of nuclear factor-kappa B ligand [RANKL]) were examined, IL-11, RANKL (from bone marrow stromal cells), and IL-6 (from osteoclasts), which regulate bone remodeling, were restored to levels similar to those in normal B6 mice. These findings indicate that not only the hemopoietic system but also the bone marrow microenvironment were normalized after IBM-BMT, resulting in an amelioration of the imbalance between bone absorption and formation.

Amino Acids↗