Search PubMed⌕ Search

Biomedical subjects

Masakazu Haneda

Publications and source records attributed to Masakazu Haneda.

At least 37 records · Page 2Linked to original sources
PubMed2005

Estrogen and raloxifene, a selective estrogen receptor modulator, ameliorate renal damage in db/db mice.

Despite the potentially protective effects of estrogen on bone and cardiovascular tissue as well as against kidney diseases, its effects on diabetic nephropathy are unknown. Here, we examined the therapeutic effectiveness of 17beta-estradiol and raloxifene, a selective estrogen receptor modulator, for preventing functional and histological alterations in the kidneys of db/db mice, a model of type 2 diabetes. In the first experiment, ovariectomized female db/db mice were treated with 17beta-estradiol for 8 weeks. The treatment significantly ameliorated albuminuria, attenuated weight gain, and reduced hyperglycemia in diabetic ovariectomized db/db mice. Histologically, the increases in mesangial area and the accumulation of fibronectin were significantly inhibited by 17beta-estradiol. In the second experiment, mice were administered vehicle or raloxifene hydrochloride (3 mg/kg/day) for 8 weeks. Raloxifene significantly reduced mesangial expansion and fibronectin accumulation in db/db mice, but in contrast to 17beta-estradiol, it failed to affect body weight or hyperglycemia. An in vitro experiment further demonstrated that raloxifene inhibited transforming growth factor beta-1-induced fibronectin transcription and AP-1 activity. Thus, our findings suggest that raloxifene, which lacks the harmful effects of estrogen, is useful for the treatment of diabetic nephropathy.

Animals↗
PubMed2005

MAPK/AP-1-dependent regulation of PAI-1 gene expression by TGF-beta in rat mesangial cells.

BACKGROUND: Receptor-regulated Smads and/or mitogen-activated protein kinases (MAPKs) are involved in transforming growth factor-beta (TGF-beta)-induced expression of various genes, including plasminogen activator inhibitor-1 (PAI-1). Because the sequence of the promoter region in rat PAI-1 gene differs from that in the human gene, we examined the mechanisms of TGF-beta-induced rat PAI-1 expression in rat mesangial cells. METHODS: TGF-beta1-induced PAI-1 and c-fos mRNA expressions were determined by Northern blot analysis. Activation of MAPKs and Smad proteins was evaluated by an immunoblot analysis. DNA binding activities of nuclear protein were examined by using an electrophoretic mobility shift assay (EMSA). The activities of PAI-1 promoter were measured by a luciferase reporter assay. RESULTS: Extracellular-regulated kinase (ERK) and c-Jun NH-terminal kinase (JNK) phosphorylation, c-fos mRNA expression, and activator protein-1 (AP-1) DNA binding activity stimulated by TGF-beta1 were completely suppressed by the ERK kinase (MEK) inhibitors. EMSA and reporter analysis revealed that an AP-1-like sequence located in the proximal region of the rat PAI-1 promoter was the target for TGF-beta1, and the disruption of this AP-1-like sequence suppressed basal and TGF-beta1-induced promoter activation. TGF-beta1 also stimulated nuclear translocation of Smads and binding to palindromic Smad binding element (SBE) located in the rat PAI-1 promoter, without being affected by MEK inhibitor. Point mutation and deletion of palindromic SBE did not affect TGF-beta1-induced rat PAI-1 promoter activity. Moreover, interferon-gamma (IFN-gamma) inhibited TGF-beta1-induced PAI-1 expression through selectively suppressing the ERK-AP-1 pathway. CONCLUSION: These results suggest that the essential requirement of MAPK/AP-1 activation for TGF-beta1-induced PAI-1 expression is unique to rat mesangial cells.

Animals↗
PubMed2005

Factors associated with frequent remission of microalbuminuria in patients with type 2 diabetes.

To estimate the frequency of remission/regression of microalbuminuria and to identify factors affecting such outcomes in Japanese patients with type 2 diabetes, we observed 216 patients with type 2 diabetes and microalbuminuria enrolled during an initial 2-year evaluation period for the next 6 years. Remission was defined as shift to normoalbuminuria and regression as a 50% reduction in urinary albumin excretion rate (AER) from one 2-year period to the next. Reduction of urinary AER was frequent, with a 6-year cumulative incidence of 51% (95% CI 42-60) for remission and 54% (45-63) for regression, whereas the frequency of progression to overt proteinuria was 28% (19-37). Microalbuminuria of short duration, the use of renin-angiotensin system-blocking drugs, and lower tertiles for HbA(1c) (<6.95%) and systolic blood pressure (<129 mmHg) were independently associated with remission or regression in the pooled logistic regression analysis. The results indicate that reduction in urinary AER occurs frequently in Japanese patients with type 2 diabetes. Early detection of microalbuminuria and a multifactorial control may result in improved outcomes for diabetic nephropathy and cardiovascular events.

Aged↗
PubMed2005

N-acetyl-seryl-aspartyl-lysyl-proline prevents renal insufficiency and mesangial matrix expansion in diabetic db/db mice.

We have previously reported that N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), which is a tetrapeptide hydrolyzed by ACE, inhibits the transforming growth factor-beta (TGF-beta)-induced expression of extracellular matrix proteins via inhibition of the Smad signaling in human mesangial cells. To test in vivo the antifibrotic efficacy of Ac-SDKP, we examined whether long-term Ac-SDKP treatment can prevent renal insufficiency and glomerulosclerosis in diabetic db/db mice. Diabetic db/db mice or nondiabetic db/m mice were treated with Ac-SDKP for 8 weeks using osmotic minipumps. The treatment with Ac-SDKP increased plasma Ac-SDKP concentrations by approximately threefold in both groups but did not affect the blood glucose levels. Histologically, the increased glomerular surface area, mesangial matrix expansion, and overproduction of extracellular matrix proteins in db/db mice were significantly inhibited by Ac-SDKP. Furthermore, Ac-SDKP treatment normalized the increased plasma creatinine value in db/db mice, whereas the albuminuria in Ac-SDKP-treated db/db mice was somewhat decreased as compared with nontreated db/db mice, although the difference was not statistically significant. In addition, the nuclear translocation of Smad3 was inhibited by Ac-SDKP. These results demonstrate that long-term Ac-SDKP treatment ameliorates renal insufficiency and glomerulosclerosis in db/db mice via inhibition of TGF-beta/Smad pathway, suggesting that Ac-SDKP could be useful in the treatment of diabetic nephropathy.

Animals↗
PubMed2005

[Revised criteria for the early diagnosis of diabetic nephropathy].

The Diabetic Nephropathy Committee recommends the use of revised criteria for the early diagnosis of diabetic nephropathy in Japan. The new criteria are as follows: 1) Urinary albumin should be determined by immunoassay using a morning spot urine sample in diabetic patients without proteinuria or with dipstick-positive(+ 1) proteinuria. 2) A urinary albumin-to-creatinine ratio ranging from 30 to 299 mg/ gCr in 2 or more of 3 specimens may be diagnosed as microalbuminuria. 3) Two alternatives, i.e. the urinary albumin excretion rate of 30-299 mg/24hr in 24hr urine collection or 20-199 microg/min in timed urine collection can be used to detect microalbuminuria. 4) Renal hypertrophy and elevated urinary type IV collagen may indicate the existence of diabetic renal disease. 5) Microalbuminuria originating in non-diabetic diseases should be excluded.

Albuminuria↗
PubMed2005

[Estimation of glomerular filtration rate by inulin clearance: comparison with creatinine clearance].

Inulin clearance (Cin) is widely believed to be the gold standard of the glomerular filtration rate (GFR). However, in Japan, Cin has not been officially recognized by the Ministry of Health, Labour and Welfare of Japan for clinical use. Creatinine clearance (Ccr) has been used to estimate the renal function of patients, but there have been many studies in which Ccr estimates were GFR falsely high because the metabolism and tubular excretion of creatinine widely varied according to the pathophysiological state of the patient. In the present study, we determined Cin and Ccr simultaneously in 116 adult patients with renal diseases and diabetic mellitus. The clearance study was performed by the modified Wesson's method. The inulin preparation was FFI-1010 (Fuji Yakuhin Co. Ltd.). Inulin in serum and urine was determined by the newly devised enzymatic assay (Toyobo Co. Ltd.), which is specific for inulin. The mean Cin was 35.0 +/- 14.4 ml/min/1.73 m2. The mean Ccr(the enzyme assay) was 63.6 +/- 24.1 ml/min/1.73 m2 and that of the kinetic Jaffe assay was 55.3 +/- 19.3 ml/min/1.73 m2. Mean Ccr/Cin was 1.93 +/- 0.73, 1.69 +/- 0.62, respectively. This ratio was significantly different(p < 0.05) in the degree of reduction of Cin, with values of 2.07 +/- 0.82 (Cin < 40 ml/min/1.73 m2) and 1.64 +/- 0.32(40 < Cin < 80 ml/min/1.73 m2), respectively. Only 8 patients were classified into the same degree of reduced renal function (the Guideline of Japanese Society of Nephrology). The findings of this study suggest that the GFR determined by Ccr could misjudge the renal function of patient and delay the administration of proper treatment of the patient. Introduction of Cin into the clinical field is necessary to avoid this delay.

Acute Disease↗
PubMed2004

Successful recovery of infective endocarditis-induced rapidly progressive glomerulonephritis by steroid therapy combined with antibiotics: a case report.

BACKGROUND: The mortality rate among patients with infective endocarditis, especially associated with the presence of complications or coexisting conditions such as renal failure and the use of combined medical and surgical therapy remains still high. Prolonged parenteral administration of a bactericidal antimicrobial agent or combination of agents is usually recommended, however, the optimal therapy for infective endocarditis associated with renal injury is not adequately defined. CASE PRESENTATION: Patient was a 24-years old man who presented to our hospital with fever, fatigue, and rapidly progressive glomerulonephritis. He had a history of ventricular septum defect (VSD). A renal biopsy specimen revealed crescentic glomerulonephritis and echocardiogram revealed VSD with vegetation on the tricuspid valve. Specimens of blood demonstrated Propionibacterium Acnes. The intensive antibiotic therapy with penicillin G was started without clinical improvement of renal function or resolution of fever over the next 7 days. After the short-term treatment of low dose of corticosteroid combined with continuous antibiotics, high fever and renal insufficiency were dramatically improved. CONCLUSION: Although renal function in our case worsened despite therapy with antibiotics, a short-term and low dose of corticosteroid therapy with antibiotics was able to recover renal function and the patient finally underwent tricuspid valve-plasty and VSD closure. We suggest that the patients with rapidly progressive glomerulonephritis associated with infective endocarditis might be treated with a short-term and low dose of corticosteroid successfully.

Adrenal Cortex Hormones↗
PubMed2004

Effect of central thyrotropin-releasing hormone on pancreatic blood flow in rats.

Central neuropeptides play a role in physiological regulation through the autonomic nervous system. Thyrotropin-releasing hormone (TRH) is a neuropeptide distributed throughout the central nervous system and acts as a neurotransmitter to regulate gastric and hepatic functions through vagal-cholinergic pathways. In this study, the central effect of TRH on pancreatic blood flow was investigated in urethane-anesthetized rats. Pancreatic blood flow was determined by laser Doppler flowmetery. After measurement of basal blood flow, a stable TRH analog, RX 77368 (1-50 ng) or saline was injected intracisternally. Pancreatic blood flow was observed for 120 min thereafter. In some experiments, pretreatment with atropine methyl nitrate (0.15 mg/kg, i.p.), NG-nitro-L-arginine-methyl ester (10 mg/kg, i.v.), or 6-hydroxydopamine (6-OHDA;180 mg/kg, i.p.), or subdiaphragmatic vagotomy was performed. Intracisternal injection of TRH analog dose-dependently increased pancreatic blood flow with a peak response occurring 30 min after injection. The stimulatory effect of TRH analog on pancreatic blood flow was blocked by vagotomy, atropine, and NG-nitro-L-arginine-methyl ester, but not by 6-hydroxydopamine. Intravenous administration of the TRH analog did not influence pancreatic blood flow in the same animal model. These results indicate that TRH acts in the central nervous system to stimulate pancreatic blood flow through vagal-cholinergic and nitric oxide-dependent pathways.

Animals↗
PubMed2004

Therapeutic efficacy of an angiotensin II receptor antagonist in patients with nonalcoholic steatohepatitis.

The therapeutic efficacy of angiotensin II receptor antagonist, losartan, was studied in patients with nonalcoholic steatohepatitis (NASH). Seven patients with both NASH and hypertension were treated with losartan (50 mg/d) for 48 weeks. Treatment with losartan resulted in a significant decrease in blood markers of hepatic fibrosis, plasma TGF-beta1 and serum ferritin concentration concurrently with an improvement in serum aminotransferase levels. Histological assessment showed improvement of hepatic necroinflammation in five patients, reduction of hepatic fibrosis in four patients, and disappearance of iron deposition in two patients. No side effect of treatment was noted at any time during the study. In conclusion, the present data raise the possibility that an angiotensin II receptor antagonist may be therapeutically efficacious for NASH.

Adult↗
PubMed2004

Antiproteinuric effect of candesartan cilexetil in Japanese subjects with type 2 diabetes and nephropathy.

The effect of the angiotensin II receptor blocker, candesartan cilexetil, on proteinuria was examined in a prospective, multicenter, randomized, double-blind study in Japanese subjects with type 2 diabetes. This study enrolled diabetic subjects with confirmed proteinuria into four groups for 12 weeks of treatment with placebo or candesartan cilexetil 2, 4, or 8 mg. The contribution of the angiotensin converting enzyme (ACE) gene polymorphism to the effect of candesartan cilexetil was also examined. In 127 subjects, candesartan cilexetil showed a dose-related reduction in proteinuria after 12 weeks of treatment (F = 9.45, P = 0.0013), with a 18.1% reduction in the 4-mg group, and a 5.8% reduction in the 8-mg group, in contrast to a 32.2% increase in the placebo group, and a 0.8% increase in the 2-mg group. These results indicate that candesartan cilexetil is useful in reducing proteinuria in diabetic subjects when compared with placebo. In addition, candesartan cilexetil seems to be effective in subjects with both the II and DD genotypes of the ACE gene.

Angiotensin Receptor Antagonists↗
PubMed2004

Peroxisome proliferator-activated receptor-gamma ligands inhibit TGF-beta 1-induced fibronectin expression in glomerular mesangial cells.

The thiazolidinedione (TZD) class of antidiabetic drugs, which are ligands for peroxisome proliferator-activated receptor (PPAR)-gamma, has been shown to possess potent anti-inflammatory and antineoplastic actions. Here, we show in mesangial cells that PPAR-gamma agonists inhibit fibronectin expression by transforming growth factor (TGF)-beta 1. TGF-beta 1 enhanced fibronectin mRNA expression, and this enhancement was abrogated by pretreatment with pioglitazone. Electrophoretic mobility shift assay identified that pioglitazone inhibited TGF-beta 1-induced DNA binding of activator protein-1 (AP-1). Pioglitazone inhibited AP-1 reporter activity but not Smad binding elements reporter activity without affecting TGF-beta 1-induced activation of mitogen-activated protein kinases (MAPKs) or Smad2. PPAR-gamma overexpression inhibited TGF-beta 1-induced fibronectin expression as well as the activation of AP-1. 15-Deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), a natural PPAR-gamma ligand, also inhibited TGF-beta1-induced fibronectin expression by suppressing AP-1 activation by TGF-beta 1. 15d-PGJ(2) inhibited the TGF-beta 1-induced MAPK activation. Dominant-negative PPAR-gamma (Delta PPAR-gamma) completely abrogated the inhibitory effect of pioglitazone and incompletely blocked its effect of 15d-PGJ(2) on TGF-beta 1-induced AP-1 reporter activity. Delta PPAR-gamma overexpression did not affect the inhibitory effect of 15d-PGJ(2) on TGF-beta 1-induced MAPK activation. In conclusion, pioglitazone inhibits TGF-beta 1-induced fibronectin expression by inhibiting AP-1 activation dependent on PPAR-gamma, while 15d-PGJ(2) acts through a dual mechanism independent of and dependent on PPAR-gamma activation in mouse mesangial cells.

Animals↗
PubMed2004

Cdx2 expression in pancreatic tumors: Relationship with prognosis of invasive ductal carcinomas.

We have previously reported that Caudal-related homeobox gene 2 (Cdx2) is a useful prognostic intestinal phenotypic marker for advanced gastric cancers. In this study, we examined Cdx2 expression and phenotype in pancreatic tumors. We evaluated 19 mucinous cystic tumors (MCTs), 17 intraductal papillary-mucinous tumors (IPMTs), and 41 invasive ductal carcinomas (IDCs) with regard to their gastrointestinal phenotype. The expression of Cdx2 was also assessed immunohistochemically. The lesions were phenotypically divided into 39 gastric (G type), 29 gastric and intestinal mixed (GI type), 3 intestinal (I type), and 6 null (N type) types, independent of the histopathological type. Most of the pancreatic tumors were thus judged to be the positive for gastric phenotypic members. Cdx2 nuclear staining demonstrated a close relation to the intestinal phenotypic expression in all three types (MCTs, IPMTs, and IDCs; p<0.05). In IDCs, Kaplan-Meier analysis of Cdx2 expression showed the Cdx2-positive group to have a significantly better outcome than their negative counterparts (p=0.015). In conclusion, our data suggest that Cdx2 might be necessary for intestinal phenotypic expression even in pancreatic tumor cells. In addition, Cdx2 expression in IDCs may be a novel prognostic marker for patient survival.

Aged↗