Koji Yazawa

Osaka City University, Ōsaka, Ōsaka, Japan

Are you Koji Yazawa?

Claim your profile

Publications (58)128.15 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background. In addition to its abundance and easy accessibility, adipose tissue yields more potent immunoregulatory stem cells (adipose tissue-derived stem cells, ADSCs) than does bone marrow. However, the beneficial effects of ADSCs on alloreactivity are scarcely known. This study evaluated the beneficial effects of ADSCs in rat kidney transplantation and analyzed the underlying molecular mechanism. Methods. Dark Agouti rat kidneys were transplanted into Lewis rats. Autologous ADSCs (2 x 10(6)) were injected through the left renal artery of the donors before the nephrectomy (ADSCs group). Graft survival, histologic changes, and the expression of several cytokines and proteins were assessed. In an in vitro experiment, the immunosuppressive capacity of ADSCs was tested in a mixed lymphocyte reaction. Results. Histologic findings of the ADSCs group revealed a reduced rejection grade, whereas the number of infiltrated CD4(+)/CD8(+) T cells was also significantly decreased as compared to the control. Relative to these findings, injection of ADSCs led to a significantly prolonged mean graft survival compared with the control. In vitro, autologous ADSCs dose-dependently suppressed alloreactive lymphocytes. Moreover, ADSCs increased the level of tumor necrosis factor-inducible gene 6 protein (TSG-6) in mixed lymphocyte reaction, which has an anti-inflammatory capacity. Recombinant TSG-6 markedly suppressed alloreactive T cells through downregulating CD44, which may lead to the suppression of T-cell activation and infiltration into allografts. Conclusion. Our findings clearly showed that ADSCs attenuated acute rejection by secreting TSG-6 as well as through direct cell interaction. These findings contribute to the clinical application of these cells in solid organ transplantation.
    Transplantation 06/2014; 98(3). DOI:10.1097/TP.0000000000000230 · 3.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Context:Vitamin D, often deficient in kidney transplant (KTx) recipients, has potential immunomodulatory effects.Objective:This study aimed to evaluate whether vitamin D status affects the rate of decline in kidney allograft function.Design, Setting, and Patients:The study included a prospective cohort of 264 ambulatory KTx recipients at a Japanese single center.Main Outcome Measures:We measured the baseline 25-hydroxyvitamin D (25D) concentration and examined its association with annual decline in estimated glomerular filtration rate (eGFR). Secondary outcome was rescue treatment with intravenous methylprednisolone (IV-MP) as an index of rejection episodes.Results:The mean serum 25D concentration was 17.1 (SD, 6.5) ng/mL, and 68.4% patients had vitamin D inadequacy or deficiency. Time after KTx was a significant effect modifier for the association of serum 25D concentration with annual eGFR change and need for IV-MP (P for interaction <0.1). We divided patients according to the median time after KTx (10 years) and found that low vitamin D was significantly associated with a rapid eGFR decline at <10 years after KTx, but not at ≥10 years after KTx. The same was true for rescue treatment with IV-MP. Overall, propensity score matching showed independent associations of low vitamin D with both outcomes. Stratified matching confirmed pronounced associations at <10 years after KTx.Conclusions:Vitamin D deficiency predicts a rapid decline in eGFR and need for IV-MP at <10 years after KTx. Future studies are warranted to evaluate the clinical efficacy of vitamin D supplementation.
    The Journal of Clinical Endocrinology and Metabolism 11/2013; 99(2). DOI:10.1210/jc.2013-2421 · 6.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 67-year-old man visited an urological clinic with a chief complaint of urination pain. Cystourethroscopy and magnetic resonance imaging (MRI) examination revealed a bladder tumor (cT3bN0M0). Marked leukocytosis and respiratory distress with pleural effusion appeared. Pulse steroid therapy improved the general condition partially. The patient was sent to our hospital for further examination. Serum granulocyte colony-stimulating factor (G-CSF) and interleukin-6 (IL-6) were high and the pathological findings of bladder tumor obtained by transurethral resection (TUR) revealed an urothelial carcinoma that produced G-CSF and IL-6. Neoadjuvant systemic chemotherapy was performed along with use of steroid and sivelestat, which ameliorated the respiratory distress. After three courses of systemic chemotherapy, serum G-CSF and IL-6 normalized and cystoprostatectomy was performed. The patient has been in good health at 20 months after the surgery with no evidence of recurrence.
    Hinyokika kiyo. Acta urologica Japonica 07/2013; 59(7):443-7.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The main objective of this study was to assess cardiac death (CD) kidney grafts before transplantation to determine whether blood oxygen level-dependent (BOLD) and diffusion MRI techniques can predict damage to these grafts after transplantation. We assessed CD kidney tissue by BOLD and diffusion MRI. We also examined pathological and gene expression changes in CD kidney grafts before and after transplantation. Although there was significantly more red cell congestion (RCC) in the inner stripe of the outer medulla (IS) in both 1 h after cardiac death (CD1h) and CD2h kidneys destined for grafts before transplantation compared with CD0h (p<0.05), CD2h, but not CD1h, kidney grafts had significantly different RCC in the IS 2 days after transplantation (p<0.05). Consistent with these pathological findings, tissue plasminogen activator (tPA) gene expression was increased only in the cortex and medulla of CD2h kidney grafts after transplantation. BOLD MRI successfully and non-invasively imaged and quantified RCC in the IS in both CD1h and CD2h kidney grafts (p<0.05). Diffusion MRI also non-invasively assessed increased the apparent diffusion coefficient in the IS and decreased it in the outer stripe (OS) of CD2h grafts, in concordance with interstitial edema in the IS and tubule cellular edema in the OS. These two types of edema in the outer medulla could explain the prolonged RCC in the IS only of CD2h kidney grafts, creating part of a vicious cycle inhibiting red cells coming out of capillary vessels in the IS. Perfusion with University of Wisconsin solution before MRI measurements did not diminish the difference in tissue damage between CD1h and CD2h kidney grafts. BOLD and diffusion MRI, which are readily available non-invasive tools for evaluating CD kidney grafts tissue damage, can predict prolonged organ damage, and therefore the outcome, of transplanted CD kidney grafts.
    PLoS ONE 05/2013; 8(5):e63573. DOI:10.1371/journal.pone.0063573 · 3.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Mesenchymal stem cells (MSCs) are an attractive therapeutic cell source fortreating renal diseases. MSCs administration has been shown to improve renalfunction, although underlying mechanisms are incompletely understood. We recentlyshowed that allogenic fetal membrane-derived MSCs (FM-MSCs), which are availablenon-invasively in large amounts, had renoprotective effect in an experimentalglomerulonephritis model. Here, we investigated whether allogenic FM-MSCsadministration could protect kidneys from ischemia/reperfusion (I/R) injury.Lewis rats were subjected to right nephrectomy and left renal I/R injury byclamping left renal artery as acute kidney injury (AKI) model. After declamping FMMSCs(5x105 cells) obtained from major histocompatibility complex (MHC) mismatched-ACI rats were intravenously administered.I/R injured rats exhibited increased serum creatinine and BUN, whereas FMMSCsadministration significantly ameliorated renal function. Histological analysisrevealed that FM-MSCs administration significantly suppressed tubular apoptosis andinfiltration of macrophages and T cells. Administration of FM-MSCs mainly homed intolung, but increased serum IL-10 levels. Of interest is that renoprotective effects of FMMSCswere abolished by using anti-IL-10 neutralization antibody, suggesting that IL-10 would be one of the candidate factors to protect rat kidney from I/R injury in thismodel. We concluded that allogenic FM-MSCs transplantation is a potent therapeuticstrategy for the treatment of AKI.
    Cell Transplantation 04/2013; 23(7). DOI:10.3727/096368913X665594 · 3.57 Impact Factor
  • The Journal of Urology 04/2013; 189(4):e865. DOI:10.1016/j.juro.2013.02.2019 · 3.75 Impact Factor
  • Transplantation 11/2012; 94(10S):445. DOI:10.1097/00007890-201211271-00842 · 3.78 Impact Factor
  • Transplantation 11/2012; 94(10S):1082-1083. DOI:10.1097/00007890-201211271-02145 · 3.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Nonadherence to treatment regimens for immunosuppressive agents is one of the major risk factors for allograft failure in kidney transplant recipients. The aim of this study was to estimate the relative effect of daily dosing on treatment adherence, not to identify how patients are non-adherent, in long-term kidney transplant recipients. METHODS: In January 2009, a cross-sectional, anonymous, and voluntary questionnaire survey was given to kidney transplant recipients who regularly visited Inoue Hospital. A self-reporting questionnaire underestimates nonadherence, but we reasoned that the effect of the dosing regimen should be estimated with relative accuracy by using the generalized ordered logit/partial proportional hazard odds model given that the distribution patterns in the degree of nonadherence have been shown to be similar with other measures. RESULTS: Of 336 eligible patients, 312 (92.9 %) participated in this study. Two hundred seventy-four patients (87.8 %) were more than 3 years post-transplant. Univariate analysis revealed that a single daily dose was significantly associated with better adherence. After controlling for age, sex, time since transplantation, and the number of prescribed drugs, the effect of a single daily dose still remained significant [odds ratio, 0.40 (95 % confidence interval, 0.19-0.81); p = 0.011]. Several sensitivity analyses yielded similar results. CONCLUSIONS: To our knowledge, this is the first report that, in long-term kidney transplant recipients, a single daily regimen-one of few modifiable factors-might improve treatment adherence and allograft survival.
    Clinical and Experimental Nephrology 10/2012; DOI:10.1007/s10157-012-0713-4 · 1.71 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Posttransplant malignancy (PTM) is a limiting factor both for patient and allograft survival in kidney transplant recipients (KTRs). We hypothesized that active vitamin D compounds (AVD) could reduce PTM development in KTRs. Ambulatory KTRs in a Japanese prospective cohort were followed from August 2007 to November 2010. The outcome of interest was newly diagnosed PTM. A propensity score (PS) of having received AVDs was estimated using 26 clinically relevant factors. We used the Cox proportional hazards model with stratification by PS tertiles on the assumption that baseline hazard functions differ among tertiles. As sensitivity analyses, we used inverse probability weighting and PS matching. Among 218 participants, the median age was 50 (interquartile range [IQR], 40 to 59) years, 63.3% were male, median time since transplantation was 11.2 (IQR, 5.2 to 17.1) years, and mean estimated GFR was 41.3 (SD, 15.6) mL/min per 1.73 m(2). At baseline, 42.2% had been treated with AVDs mainly for glucocorticoid-induced osteoporosis. AVDs used were calcitriol (58.7%) and alfacalcidol (41.3%). During follow-up, PTM developed in 5.4% of 92 AVD users and 8.7% of 126 nonusers. Poor vitamin D status was common in the participants, but the serum 25-hydroxyvitamin D level was not significantly associated with PTM in Cox regression analysis. After stratifying patients by PS tertiles, we found that AVDs were significantly associated with a lower risk of PTM (HR 0.25 [0.07 to 0.82]). Sensitivity analyses yielded similar results. AVDs are potential chemopreventive agents against PTM in KTRs. Cancer Prev Res; 5(10); 1229-35. ©2012 AACR.
    Cancer Prevention Research 08/2012; 5(10):1229-35. DOI:10.1158/1940-6207.CAPR-12-0218 · 5.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background Recent studies have identified T cells and natural killer T (NKT) cells as important mediators in renal ischemia-reperfusion (I/R) injury. The recruitment of these cells is induced by chemotaxis factors. We investigated the effects of blocking CXCR3 and CCR5 by an antagonist (TAK) using a rat renal I/R injury model.Methods The Sprague-Dawley rats were either subjected to sham operation or left renal occlusion for 45 min followed by reperfusion and contralateral nephrectomy. The control or TAK groups were, respectively, injected phosphate-buffered saline or TAK at 30 min prior to clamp. Serum creatinine, tubular injury, chemokines expression and infiltrating cells were assessed.ResultsTAK treatment significantly suppressed the elevation in serum creatinine (sham 0.40 ± 0.05 mg/dL, control 2.86 ± 0.67 mg/dL, TAK 1.60 ± 0.73 mg/dL) and resulted in a lower tubular injury score compared with the control group (sham 0, control 4.8 ± 0.3, TAK 3.3 ± 1). The mRNA expression of chemokines that bind to CXCR3 and CCR5 in the post-ischemic kidneys was elevated at 1 h after reperfusion in each group. Moreover, the infiltration of CD4+ T cells and CD8+ NKT cells in the control group increased compared with the sham group and TAK injection significantly suppressed the number of CD4+ T cells (sham 13.5 ± 3.5 × 10(4) cells, control 28.9 ± 15.4 × 10(4) cells, TAK 11.8 ± 3.5 × 10(4) cells) and the number of CD8+ NKT cells (sham 11.7 ± 5.4 × 10(4) cells, control 30.1 ± 8.6 × 10(4) cells, TAK 11.8 ± 2.9 × 10(4) cells).Conclusions These findings suggest that the blocking of CXCR3 and CCR5 suppress the infiltration of T cells and NKT cells and have a protective effect on kidneys that are injured by I/R.
    Nephrology Dialysis Transplantation 08/2012; DOI:10.1093/ndt/gfs360 · 3.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: The tissue-protective effects of erythropoietin (EPO) have been extensively investigated, and EPO administration can raise the hemoglobin (Hb) concentration. Recently, we reported that carbamylated erythropoietin (CEPO) protected kidneys from ischemia-reperfusion injury as well as EPO. METHODS: To investigate the clinical applications of CEPO, we next evaluated the long-term therapeutic effect of CEPO using a tubulointerstitial model rat. We randomized remnant kidney model rats to receive saline, EPO, or CEPO for 8 weeks. RESULTS: CEPO- and EPO-treated rats had improved serum creatinine levels compared with saline-treated remnant kidney model rats, although the Hb level was significantly increased in EPO-treated rats. Two-photon microscopy revealed that EPO/CEPO significantly ameliorated tubular epithelial cell damage assessed by endocytosis. In addition, CEPO or EPO protected endothelial cells with a sustained blood flow rate. EPO or CEPO suppressed the number of TUNEL-positive apoptotic cells with weak αSMA staining. Furthermore, PCR analysis demonstrated that TGF-β and type I collagen expression was attenuated in EPO- or CEPO-treated rats, accompanied by a significant decrease in interstitial fibrosis. CONCLUSION: We established a long-term therapeutic approach to protect tubulointerstitial injury with CEPO, and thus, the therapeutic value of this approach warrants further attention and preclinical studies.
    Clinical and Experimental Nephrology 06/2012; 16(6). DOI:10.1007/s10157-012-0647-x · 1.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Renal ischemia-reperfusion (I/R) injury is unavoidable in kidney transplantation and frequently influences both short- and long-term allograft survival rates. One of the major events in I/R injury is the generation of cytotoxic oxygen radicals. Recently, hydrogen gas has been reported to display antioxidant properties and protective effects against organ dysfunction induced by various I/R injuries. We investigated whether hydrogen-rich University of Wisconsin (HRUW) solution attenuates renal cold I/R injury. We prepared HRUW solution by a novel method involving immersion of centrifuge tubes containing UW solution into hydrogen-saturated water. Hydrogen readily permeates through the centrifuge tubes, and thus, the hydrogen concentration of the UW solution gradually increases in a time-dependent manner. Syngeneic rat kidney transplantation was performed, and the animals were divided into three groups: recipients with nonpreserved grafts (control group), recipients with grafts preserved in UW solution for 24 to 48 hr (UW group), and recipients with grafts preserved in HRUW solution for 24 to 48 hr (HRUW group). In the early phases, HRUW solution decreased oxidative stress, tubular apoptosis, and interstitial macrophage infiltration in the kidney grafts. Consequently, HRUW solution improved renal function and prolonged recipient survival rate compared with simple cold storage using UW solution. Histopathologically, HRUW treatment alleviated tubular injury and suppressed development of interstitial fibrosis. HRUW solution improved graft function and prolonged graft survival compared with simple cold storage using UW solution by protecting tubular epithelial cells from inflammation and apoptosis. Our new method of organ preservation is a groundbreaking, safe, and simple strategy that may be applied in the clinical setting.
    Transplantation 06/2012; 94(1):14-21. DOI:10.1097/TP.0b013e318255f8be · 3.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Two siblings with autosomal recessive Alport syndrome (ARAS) obtained renal transplants from their consanguineous parents. Their COL4A3 mRNA transcripts were disrupted by a 139 bp intronic sequence between exon 48 and 49, which was derived from an antisense Alu element in this intron. The new amino acid sequence from the cryptic exon was terminated by a stop codon at the 1511th codon, resulting in the loss of 76 % α3(IV)NC1. This is the first case report of kidney transplantations between ARAS-homozygous siblings and their heterozygous parents. The brother experienced acute rejection just after transplantation and post-transplantation anti-glomerular basement membrane (GBM) nephritis, whereas the sister has experienced no problems to date. The anti-GBM nephritis could have resulted from the acute rejection. The COL4A3 gene heterozygous mutated parents, who are possibly at risk for thin basement membrane disease, have maintained their renal functions without urinary abnormalities after renal transplantation to date.
    05/2012; 2(1). DOI:10.1007/s13730-012-0049-7
  • The Journal of Urology 04/2012; 187(4):e914-e915. DOI:10.1016/j.juro.2012.02.2445 · 3.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The introduction of cyclosporine (CsA) has improved graft survival, but it causes nephropathy, which limits its clinical utility. Recently, we reported that carbamylated erythropoietin (CEPO) protected kidneys from ischemia reperfusion injury as well as EPO. To investigate the clinical applications of CEPO, we next evaluated the long-term therapeutic effect of CEPO using a CsA-induced nephropathy model. CsA caused renal dysfunction, while EPO/CEPO administration significantly improved renal function. EPO treatment significantly increased Hb concentration, while CEPO treatment neither enhanced nor reduced Hb concentration. CsA treatment induced tubular apoptosis, while EPO/CEPO administration inhibited it and increased PI3 kinase activation and Akt phosphorylation. In parallel, morphological assessment revealed that EPO/CEPO significantly reduced CsA-induced interstitial fibrosis and inhibited interstitial macrophage infiltration. In addition, real-time RT-PCR demonstrated that cortical mRNA levels of TGF-β1 and type I collagen were suppressed in the EPO/CEPO group. These results suggest a new therapeutic approach using CEPO to protect kidneys from CsA-induced nephropathy.
    Cell Transplantation 03/2012; 21(2-3):571-80. DOI:10.3727/096368911X605501 · 3.57 Impact Factor
  • European Urology Supplements 02/2012; 11(1):e214. DOI:10.1016/S1569-9056(12)60211-5 · 3.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The chemokine receptors CCR5 and CXCR3 are expressed by T cells and macrophages. We examined effects of a CCR5/CXCR3 antagonist (TAK), with a particular focus on the role of macrophages, in a rat kidney transplant model. Dark Agouti rat kidneys were transplanted into Lewis rats. The recipients were treated daily with a 10 mg/kg TAK on posttransplant days 0 to 14 and/or 2 mg/kg of cyclosporine A (CsA) on days 0 to 5. Graft survival, histological changes, and the expression of chemokines and chemokine receptors on T cells and macrophages were studied. Treatment with TAK alone suppressed CD4+T cell infiltration and slightly prolonged graft survival. The expressions of both CCR5 and CXCR3, and activated macrophage-associated cytokines and chemokines, were significantly increased on macrophages that had been separated from rejecting kidneys, compared with those from spleens. However, these upregulations were decreased in macrophages from kidneys that had been treated with TAK. Immunohistochemistry also showed that macrophages infiltrating tubules of rejecting kidney expressed both receptors. In the CsA alone group, macrophages were the dominant infiltrating cells, and all allografts were rejected within 10 days. A combined therapy involving CsA and TAK resulted in decreased macrophage infiltration, and graft survival was substantially prolonged. The levels of activated macrophage-associated cytokines and chemokines were also decreased. The dual blocking of CCR5/CXCR3 can be useful in decreasing rejection, with or without CsA. This mechanism acts, not only to block T-cell recruitment to a kidney graft but to suppress the infiltration of macrophages as well.
    Transplantation 11/2011; 93(1):24-31. DOI:10.1097/TP.0b013e31823aa585 · 3.78 Impact Factor
  • The Journal of Urology 04/2011; 185(4). DOI:10.1016/j.juro.2011.02.2488 · 3.75 Impact Factor
  • The Journal of Urology 04/2011; 185(4). DOI:10.1016/j.juro.2011.02.2492 · 3.75 Impact Factor

Publication Stats

290 Citations
128.15 Total Impact Points


  • 2001–2014
    • Osaka City University
      • Department of Urology
      Ōsaka, Ōsaka, Japan
  • 2011–2013
    • Osaka University
      Suika, Ōsaka, Japan
  • 2006–2008
    • Osaka General Medical Center
      Ōsaka, Ōsaka, Japan
  • 2003
    • Kanazawa University
      Kanazawa, Ishikawa, Japan
  • 1998–2000
    • Hyogo Prefectural Amagasaki Hospital
      Amagasaki, Hyōgo, Japan