Kazuyoshi Okada

Dr. Kazuyoshi Okada


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
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HKHiroki Kobayashi
Hiroki Kobayashi
MAMasanori Abe
Masanori Abe
YYYoshinori Yoshida
Yoshinori Yoshida
HSHiroko Suzuki
Hiroko Suzuki
NMNoriaki Maruyama
Noriaki Maruyama
KOKazuyoshi Okada
Kazuyoshi Okada
Compared with glycated hemoglobin (HbA1c), glycated albumin (GA) is superior in estimating glycemic control in diabetic patients on hemodialysis (HD). However, the better index for assessment of glycemic control in diabetic patients on peritoneal dialysis (PD) and the impact of protein loss on GA are unknown. Twenty diabetic patients on HD were matched by age, sex, and baseline postprandial plasma glucose (PG) levels to 20 PD patients. PG, HbA1c, GA, and serum albumin levels were measured for six months. Protein loss in PD patients was estimated by measuring the protein concentration in the peritoneal dialysate and by 24 h urine collection. Although PG and HbA1c did not differ significantly between the groups, the PD group had significantly lower GA (17.8% versus 20.8%, p < 0.001) and GA/HbA1c ratio (2.95% versus 3.45%, p < 0.0001) than the HD group. Although the PG level correlated significantly with the GA levels in both groups, it was not correlated with the HbA1c levels in both groups. HbA1c level was negatively associated with erythropoiesis-stimulating agent (ESA) dose in both groups, whereas GA was not significantly associated with serum albumin, hemoglobin concentration, ESA dose, and protein loss. Multiple regression analysis identified GA as the only independent factor associated with PG in PD patients. Our results suggested that GA was not significantly associated with protein loss, hemoglobin, serum albumin, and ESA dose. Although GA might underestimate glycemic status, it provided a significantly better measure for estimating glycemic control than HbA1c, even in PD patients.

25 April 2016 in Diabetes Research and Clinical Practice
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Journal Article
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MAMasanori Abe
Masanori Abe
HTHiguchi Terumi
Higuchi Terumi
MMMasari Moriuchi
Masari Moriuchi
MOMasahiro Okamura
Masahiro Okamura
RTRitsukou Tei
Ritsukou Tei
KOKazuyoshi Okada
Kazuyoshi Okada
Saxagliptin is a dipeptidyl peptidase-4 inhibitor that was approved in Japan for the treatment of type 2 diabetes in 2013. We examined its efficacy and safety in Japanese hemodialysis patients with diabetic nephropathy. In this prospective, open-label, parallel-group study, Japanese hemodialysis patients were randomized to receive either oral saxagliptin (2.5mg/day) or usual care (control group) for 24weeks. Before randomization, patients received fixed doses of conventional antidiabetic drugs (oral drugs and/or insulin) for 8weeks; these drugs were continued during the study. Endpoints included changes in glycated albumin (GA), hemoglobin A1c (HbA1c), postprandial plasma glucose (PPG), and adverse events. Both groups included 41 patients. Mean GA, HbA1c, and PPG decreased significantly in the saxagliptin group (-3.4%, -0.6% [-7mmol/mol], and -38.3mg/dL, respectively; all P<0.0001) but not in the control group (0%, -0.1% [-1mmol/mol], and -3.7mg/dL, respectively) (P<0.0001, P<0.001, and P<0.0001, respectively). In saxagliptin-treated patients, the reduction in GA was significantly greater when saxagliptin was administered as monotherapy than in combination therapy (-4.2% vs. -3.0%, P=0.012) despite similar baseline values (24.5% vs. 23.3%). Reductions in GA, HbA1c, and PPG were greater in patients whose baseline values exceeded the median (23.8% for GA, 6.6% for HbA1c, and 180mg/dL for PPG). There were no adverse events associated with saxagliptin. Saxagliptin (2.5mg/day) was effective and well tolerated when used as monotherapy or combined with other antidiabetic drugs in Japanese hemodialysis patients with type 2 diabetes. UMIN000018445.

16 April 2015 in Stem Cell Research & Therapy
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Journal Article
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TMTakashi Maruyama
Takashi Maruyama
Noboru FukudaNoboru Fukuda
Noboru Fukuda
TMTaro Matsumoto
Taro Matsumoto
KKKoichiro Kano
Koichiro Kano
MEMorito Endo
Morito Endo
HKHiroshi Kawachi
Hiroshi Kawachi
Introduction: Implantation of mesenchymal stem cells (MSCs) has recently been reported to repair tissue injuries through anti-inflammatory and immunosuppressive effects. We established dedifferentiated fat (DFAT) cells that show identical characteristics to MSCs. Methods: We examined the effects of 106 of DFAT cells infused through renal artery or tail vein on monoclonal antibody (mAb) 1-22-3-induced glomerulonephritis (as an immunological type of renal injury) and adriamycin-induced nephropathy (as a non-immunological type of renal injury) in rats. The mAb 1-22-3-injected rats were also implanted with 106 of DFAT cells transfected with TSG-6 siRNA through tail vein. Results: Although DFAT cells transfused into blood circulation through the tail vein were trapped mainly in lungs without reaching the kidneys, implantation of DFAT cells reduced proteinuria and improved glomerulosclerosis and interstitial fibrosis. Implantation of DFAT cells through the tail vein significantly decreased expression of kidney injury molecule-1, collagen IV and fibronectin mRNAs, whereas nephrin mRNA expression was increased. Implantation of DFAT cells did not improve adriamycin-induced nephropathy, but significantly decreased the glomerular influx of macrophages, common leukocytes and pan T cells. However, the glomerular influx of helper T cells, was increased. Implantation of DFAT cells decreased expression of interleukin (IL)-6 and IL-12β mRNAs and increased expression of TNF-stimulated gene (TSG)-6 mRNA in renal cortex from mAb 1-22-3-injected rats. The basal level of TSG-6 protein was significantly higher in DFAT cells than in fibroblasts. Expression of TSG-6 mRNA in MCs cocultured with DFAT cells was significantly higher than in mesangial cells or DFAT cells alone. Systematic implantation of DFAT cells with TSG-6 siRNA through tail vein did not improve proteinuria, renal dysfunction and renal degeneration in the mAb 1-22-3-injected rats. Conclusion: Systematic implantation of DFAT cells effectively ameliorated mAb 1-22-3-induced glomerulonephritis through immunosuppressive effects accompanied by the suppression of macrophage infiltration and expression of IL-6, IL-10 and IL-12β, and increased production of serum and renal TSG-6 that improved the mAb 1-22-3-induced renal degeneration by the immunosuppressive effects of TSG-6. Thus DFAT cells will be suitable cell source for the treatment of immunological progressive renal diseases.

Verified
Journal Article
Open access
PDF file
TFTetsuya Furukawa
Tetsuya Furukawa
KOKazuyoshi Okada
Kazuyoshi Okada
MAMasanori Abe
Masanori Abe
RTRitsukou Tei
Ritsukou Tei
OOOsamu Oikawa
Osamu Oikawa
TMTakashi Maruyama
Takashi Maruyama
Continuous erythropoietin receptor activator (CERA) seems to maintain a stable hemoglobin (Hb) level because its half-life is longer than darbepoetin α (DA). Twenty chronic kidney disease (CKD) patients at the pre-dialysis stage who had been administered DA for over 24 weeks were randomly assigned to receive subcutaneous CERA or DA once every four weeks during 48 weeks. In both groups, the rate of achievement of target Hb level changed from 70% to 100% in weeks 0 to 48, with no significant difference between the groups. Compared with week 0, the Hb level was significantly increased from week 24 in the DA group and from week 8 in the CERA group. In addition, the reticulocyte count was significantly increased from week 4 in the CERA group compared with the DA group. There was no significant difference in the levels of estimated glomerular filtration rate and iron status between both groups. Because of the small number of patients in this study, only limited conclusions can be drawn. However, the results suggest that subcutaneous administration of DA or CERA once every four weeks to predialysis patients has similar effects on achievement of target Hb levels.