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Papers - ITOH Hiroshi

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Relationship between Stage of Diabetic Retinopathy and Pulse Wave Velocity in Japanese Patients with Type 2 Diabetes

Tanaka, K., Kawai, T., Saisho, Y., Meguro, S., Harada, K., Satoh, Y., Kobayashi, K., Mizushima, K., Abe, T. and Itoh, H.

J Diabetes Res 2013 193514 2013

ISSN 2314-6745

Objectives. We investigated the relationship between the stage of diabetic retinopathy and pulse wave velocity (PWV). Methods. This was a cross-sectional study of 689 patients (406 men and 283 women) with type 2 diabetes who were admitted to our hospital from 2004 to 2007. Brachial-ankle pulse wave velocity (baPWV) was measured by an arterial pressure measurement device as PWV/ABI. Diagnosis of diabetic retinopathy was made by ophthalmologists based on the Davis classification: no diabetic retinopathy (NDR), simple retinopathy (SDR), pre-proliferative retinopathy (pre-PDR), and proliferative retinopathy (PDR). Results. There was a significant difference in PWV between patients without diabetic retinopathy (1657.0 +/- 417.9 m/s (mean +/- SD)) and with diabetic retinopathy (1847.1 +/- 423.9 m/s) (P < 0.001). In addition, the stage of diabetic retinopathy was associated with aortic PWV (1657.0 +/- 417.9 m/s in NDR (n = 420), 1819.4 +/- 430.3 m/s in SDR (n = 152), 1862.1 +/- 394.0 m/s in pre-PDR (n = 54), and 1901.1 +/- 433.5 m/s in PDR (n = 63) (P < 0.001)). Conclusions. In patients with diabetic retinopathy, even in those with SDR, PWV was higher than that in patients without diabetic retinopathy. Physicians should therefore pay attention to the value of PWV and macroangiopathy regardless of the stage of diabetic retinopathy.

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Marked decline in beta cell function during pregnancy leads to the development of glucose intolerance in Japanese women

Saisho, Y., Miyakoshi, K., Ikenoue, S., Kasuga, Y., Matsumoto, T., Minegishi, K., Yoshimura, Y. and Itoh, H.

Endocr J 60 ( 4 ) 533 - 9 2013

ISSN 0918-8959

The aim of this study is to investigate glucose metabolism longitudinally during pregnancy to explore mechanisms underlying gestational diabetes mellitus (GDM). We reviewed a total of 62 pregnant Japanese women who underwent a 75g oral glucose tolerance test (OGTT) twice during pregnancy (median: early, 13; late, 28 weeks' gestation) because of positive GDM screening. All showed normal OGTT results in early pregnancy. Based on late OGTT, 15 had GDM (late-onset GDM) and 47 normal glucose tolerance (NGT). In early pregnancy, there were no significant differences in insulin sensitivity (insulin sensitivity index derived from OGTT [IS(OGTT)] and homeostasis model assessment for insulin resistance [HOMA-IR]) and insulin secretion (a ratio of the total area-under-the-insulin-curve to the total area-under-the-glucose-curve [AUC(ins/glu)] and insulinogenic index [IGI]) between the NGT and late-onset GDM groups. In each group, insulin sensitivity significantly decreased from early to late pregnancy, most in the late-onset GDM group (each p < 0.05). The insulin secretion showed no significant changes with advancing pregnancy in both of the groups, although late-onset GDM showed significantly lower IGI compared with NGT in late OGTT (p < 0.05). When assessed beta cell function by OGTT-derived disposition index (i.e. Insulin Secretion-Sensitivity Index-2 and IGI/fasting insulin), the indices significantly decreased from early to late pregnancy in the both groups (each p < 0.05). Women with late-onset GDM showed significantly lower indices compared with NGT (each p < 0.05). The failure of beta cell to compensate for decreased insulin sensitivity could contribute to the development of the late-onset GDM.

Association between beta cell function and future glycemic control in patients with type 2 diabetes

Saisho, Y., Kou, K., Tanaka, K., Abe, T., Shimada, A., Kawai, T. and Itoh, H.

Endocr J 60 ( 4 ) 517 - 23 2013

ISSN 0918-8959

The aim of this study was to clarify the association between C-peptide immunoreactivity (CPR), a marker of beta cell function, and future glycemic control in patients with type 2 diabetes. We conducted a retrospective analysis of 513 consecutive patients with type 2 diabetes who were admitted to our hospital between 2000 and 2007 and followed up for 2 years. Serum and urinary CPR levels were measured during admission, and CPR index was calculated as the ratio of CPR to plasma glucose. The associations between these markers at baseline and glycemic control after 2 years were assessed by means of logistic regression models. After 2 years, 167 patients (32.6%) showed good glycemic control (HbA1c <6.9%). Baseline serum and urinary CPR indices were significantly associated with good glycemic control after 2 years, and the postprandial CPR to plasma glucose ratio (postprandial CPR index) showed the strongest association (odds ratio (OR) 1.29, 95% confidence interval (CI) 1.12-1.50, P = 0.001) among CPR indices. Multivariate analyses showed consistent results (OR 1.23, 95%CI 1.03-1.48, P = 0.021). In conclusion, preserved beta cell function at baseline was associated with better glycemic control thereafter in patients with type 2 diabetes.

C-reactive protein, high-molecular-weight adiponectin and development of metabolic syndrome in the Japanese general population: a longitudinal cohort study

Saisho, Y., Hirose, H., Roberts, R., Abe, T., Kawabe, H. and Itoh, H.

PLoS One 8 ( 9 ) e73430 2013

ISSN 1932-6203

AIMS: To clarify predictive values of C-reactive protein (CRP) and high-molecular-weight (HMW) adiponectin for development of metabolic syndrome. RESEARCH DESIGN AND METHODS: We conducted a prospective cohort study of Japanese workers who had participated in an annual health checkup in 2007 and 2011. A total of 750 subjects (558 men and 192 women, age 46+/-8 years) who had not met the criteria of metabolic syndrome and whose CRP and HMW-adiponectin levels had been measured in 2007 were enrolled in this study. Associations between CRP, HMW-adiponectin and development of metabolic syndrome after 4 years were assessed by logistic regression analysis and their predictive values were compared by receiver operating characteristic analysis. RESULTS: Among 750 subjects, 61 (8.1%) developed metabolic syndrome defined by modified National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) criteria and 53 (7.1%) developed metabolic syndrome defined by Japan Society for the Study of Obesity (JASSO) in 2011. Although CRP and HMW-adiponectin were both significantly correlated with development of metabolic syndrome, multivariate logistic regression analysis revealed that HMW-adiponectin but not CRP was associated with metabolic syndrome independently of BMI or waist circumference. Adding these biomarkers to BMI or waist circumference did not improve the predictive value for metabolic syndrome. CONCLUSION: Our findings indicate that the traditional markers of adiposity such as BMI or waist circumference remain superior markers for predicting metabolic syndrome compared to CRP, HMW-adiponectin, or the combination of both among the Japanese population.

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Past Obesity as well as Present Body Weight Status Is a Risk Factor for Diabetic Nephropathy

Meguro, S., Kabeya, Y., Tanaka, K., Kawai, T., Tomita, M., Katsuki, T., Oikawa, Y., Atsumi, Y., Shimada, A., Tanaka, M., Irie, J., Saisho, Y. and Itoh, H.

Int J Endocrinol 2013 590569 2013

ISSN 1687-8337

Aims. We analyzed the prevalence of nephropathy according to past body weight status in Japanese subjects with type 2 diabetes because the influence of past obesity on diabetic complications is not certain. Methods. We examined the prevalence of nephropathy in 2927 subjects with type 2 diabetes mellitus according to current BMI and maximum BMI in the past. We defined "current obesity" as BMI on hospitalization of 25 or more, "previous obesity" as BMI on hospitalization of less than 25 and self-reported maximum BMI in the past of 25 or more, and "continuously lean" as maximum BMI of less than 25. Results. The prevalence of nephropathy was significantly higher in subjects with current obesity (40.6%) or previous obesity (35.6%) than in those who were continuously lean (24.3%) (P < 0.017). In logistic regression analysis, previous obesity, as well as current obesity, was a significant risk factor for nephropathy, independent of sex, age, disease duration, hypertension, dyslipidemia, HbA1c, and diabetic retinopathy. Conclusions. Obesity in the past, as well as the present body weight status, was a risk factor for diabetic nephropathy.

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The role of individual domains and the significance of shedding of ATP6AP2/(pro)renin receptor in vacuolar H(+)-ATPase biogenesis

Kinouchi, K., Ichihara, A., Sano, M., Sun-Wada, G. H., Wada, Y., Ochi, H., Fukuda, T., Bokuda, K., Kurosawa, H., Yoshida, N., Takeda, S., Fukuda, K. and Itoh, H.

PLoS One 8 ( 11 ) e78603 2013

ISSN 1932-6203

The ATPase 6 accessory protein 2 (ATP6AP2)/(pro)renin receptor (PRR) is essential for the biogenesis of active vacuolar H(+)-ATPase (V-ATPase). Genetic deletion of ATP6AP2/PRR causes V-ATPase dysfunction and compromises vesicular acidification. Here, we characterized the domains of ATP6AP2/PRR involved in active V-ATPase biogenesis. Three forms of ATP6AP2/PRR were found intracellularly: full-length protein and the N- and C-terminal fragments of furin cleavage products, with the N-terminal fragment secreted extracellularly. Genetic deletion of ATP6AP2/PRR did not affect the protein stability of V-ATPase subunits. The extracellular domain (ECD) and transmembrane domain (TM) of ATP6AP2/PRR were indispensable for the biogenesis of active V-ATPase. A deletion mutant of ATP6AP2/PRR, which lacks exon 4-encoded amino acids inside the ECD (Delta4M) and causes X-linked mental retardation Hedera type (MRXSH) and X-linked parkinsonism with spasticity (XPDS) in humans, was defective as a V-ATPase-associated protein. Prorenin had no effect on the biogenesis of active V-ATPase. The cleavage of ATP6AP2/PRR by furin seemed also dispensable for the biogenesis of active V-ATPase. We conclude that the N-terminal ECD of ATP6AP2/PRR, which is also involved in binding to prorenin or renin, is required for the biogenesis of active V-ATPase. The V-ATPase assembly occurs prior to its delivery to the trans-Golgi network and hence shedding of ATP6AP2/PRR would not affect the biogenesis of active V-ATPase.

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A large coronary aneurysm and its probable precursor lesions in a patient with autosomal dominant polycystic kidney disease: an implication for the process of aneurysmogenesis

Ohara, K., Kimura, T., Karasawa, T., Tokuyama, H., Wakino, S., Hayashi, K., Itoh, H. and Okada, Y.

Pathol Int 62 ( 11 ) 758 - 62 2012.11

ISSN 1320-5463

Coronary artery aneurysms are rare complications of autosomal dominant polycystic kidney disease (ADPKD), and their pathogenesis remains poorly understood. We report an autopsy case of a 64-year-old ADPKD patient with an asymptomatic, large (4 cm in diameter) saccular aneurysm arising from the left circumflex (LCX) branch of the coronary artery with only mild atherosclerotic changes. Autopsy also revealed small, focal defects of media with or without microaneurysm formation in the LCX, mesenteric and renal arteries, and a fibromuscular dysplasia-like lesion with microaneurysm in the common iliac artery. Since polycystin-1 and -2 are expressed in arterial smooth-muscle cells, these findings imply that abnormal polycystin expression in ADPKD initially causes the focal medial defects, some of which might later progress to microaneurysms and then overt aneurysms. To the best of our knowledge, this is the first description of the pathologic findings of an ADPKD-associated coronary aneurysm and its probable precursor lesions in arteries.

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[The ACE2/Ang(1-7)/Mas receptor axis in cardiovascular and renal diseases]

Kanda, T. and Itoh, H.

Nihon Rinsho 70 ( 9 ) 1487 - 91 2012.09

ISSN 0047-1852

The renin-angiotensin-aldosterone system(RAAS) plays a crucial role in the regulation of physiological homeostasis and diseases such as hypertension, coronary artery disease and chronic renal failure. In this cascade, the ACE/Ang II/AT1 receptor axis induces pathological effects, such as vasoconstriction, cell proliferation and fibrosis. Recently the ACE2/Ang(1-7)/Mas receptor axis has been recognized as a negative regulator of the RAAS. ACE2 metabolizes Ang II into Ang(1-7), which has opposite properties of Ang II through Mas receptor activation. Both animal and human studies provide strong evidence that the ACE2/Ang(1-7)/Mas receptor axis is protective for end-organ damage. Therefore, the ACE2/Ang(1-7)/Mas receptor axis could be a therapeutic target for coronary artery disease and chronic renal failure.

[Current status of vaccination therapy for hypertension]

Sasamura, H., Azegami, T. and Itoh, H.

Nihon Rinsho 70 ( 9 ) 1627 - 32 2012.09

ISSN 0047-1852

The renin-angiotensin system (RAS) plays a central role in the control of systemic blood pressure. Since the 1950s, both laboratory and clinical studies have been performed to test the efficacy of vaccines against the RAS for the management of hypertension. Although initial studies using renin vaccines and angiotensin I vaccines were unsuccessful, a recent phase IIa study has shown that vaccination against angiotensin II is effective for the treatment of patients with essential hypertension. Results from animal studies have also suggested that vaccination against the AT1 receptor may be effective not only for lowering blood pressure, but also for the prevention of hypertensive end-organ damage. In the future, the RAS may be an important target for the development of vaccines not only for the treatment, but also for the prevention of hypertension and hypertensive complications.

Loss of Pdk1-Foxo1 signaling in myeloid cells predisposes to adipose tissue inflammation and insulin resistance

Kawano, Y., Nakae, J., Watanabe, N., Fujisaka, S., Iskandar, K., Sekioka, R., Hayashi, Y., Tobe, K., Kasuga, M., Noda, T., Yoshimura, A., Onodera, M. and Itoh, H.

Diabetes 61 ( 8 ) 1935 - 48 2012.08

ISSN 0012-1797

Chronic inflammation in adipose tissue contributes to obesity-related insulin resistance. The 3-phosphoinositide-dependent protein kinase 1 (Pdk1)/forkhead transcription factor (Foxo1) pathway is important in regulating glucose and energy homeostasis, but little is known about this pathway in adipose tissue macrophages (ATMs). To investigate this, we generated transgenic mice that carried macrophage/granulocyte-specific mutations, including a Pdk1 knockout (LysMPdk1(-/-)), a Pdk1 knockout with transactivation-defective Foxo1 (Delta256LysMPdk1(-/-)), a constitutively active nuclear (CN) Foxo1 (CNFoxo1(LysM)), or a transactivation-defective Foxo1 (Delta256Foxo1(LysM)). We analyzed glucose metabolism and gene expression in ATM populations isolated with fluorescence-activated cell sorting. The LysMPdk1(-/-) mice exhibited elevated M1 macrophages in adipose tissue and insulin resistance. Overexpression of transactivation-defective Foxo1 rescued these phenotypes. CNFoxo1(LysM) promoted transcription of the C-C motif chemokine receptor 2 (Ccr2) in ATMs and increased M1 macrophages in adipose tissue. On a high-fat diet, CNFoxo1(LysM) mice exhibited insulin resistance. Pdk1 deletion or Foxo1 activation in bone marrow-derived macrophages abolished insulin and interleukin-4 induction of genes involved in alternative macrophage activation. Thus, Pdk1 regulated macrophage infiltration by inhibiting Foxo1-induced Ccr2 expression. This shows that the macrophage Pdk1/Foxo1 pathway is important in regulating insulin sensitivity in vivo.

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A case of hypoglycemic hemiparesis and literature review

Yoshino, T., Meguro, S., Soeda, Y., Itoh, A., Kawai, T. and Itoh, H.

Ups J Med Sci 117 ( 3 ) 347 - 51 2012.08

ISSN 0300-9734

An 89-year-old man with diabetes treated with metformin 500 mg/day and glimepiride 4 mg/day was hospitalized because of hypoglycemic right hemiparesis and dysarthria (casual glucose value 1.8 mmol/L), which resolved quickly following administration of 40 mL of 40% dextrose. Hemiparesis is a rare symptom (4.2%) of hypoglycemia. There are about 200 case reports of hypoglycemic hemiparesis. The average glucose level at which hemiparesis developed was 1.8 mmol/L. Right-sided hemiparesis predominated (R 66%; L 34%). On imaging studies, abnormal findings were frequently observed in the internal capsule or splenium of the corpus callosum. The mechanism of hemiparesis is not fully understood. The existence of cases in which hypoglycemia cannot be distinguished from stroke on imaging studies suggests the importance of measurement of the blood glucose level when the symptoms of stroke are first recognized.

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Coenzyme Q10 reverses mitochondrial dysfunction in atorvastatin-treated mice and increases exercise endurance

Muraki, A., Miyashita, K., Mitsuishi, M., Tamaki, M., Tanaka, K. and Itoh, H.

J Appl Physiol (1985) 113 ( 3 ) 479 - 86 2012.08

ISSN 0161-7567

Statins are cholesterol-lowering drugs widely used in the prevention of cardiovascular diseases; however, they are associated with various types of myopathies. Statins inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and thus decrease biosynthesis of low-density lipoprotein cholesterol and may also reduce ubiquinones, essential coenzymes of a mitochondrial electron transport chain, which contain isoprenoid residues, synthesized through an HMG-CoA reductase-dependent pathway. Therefore, we hypothesized that statin treatment might influence physical performance through muscular mitochondrial dysfunction due to ubiquinone deficiency. The effect of two statins, atorvastatin and pravastatin, on ubiquinone content, mitochondrial function, and physical performance was examined by using statin-treated mice. Changes in energy metabolism in association with statin treatment were studied by using cultured myocytes. We found that atorvastatin-treated mice developed muscular mitochondrial dysfunction due to ubiquinone deficiency and a decrease in exercise endurance without affecting muscle mass and strength. Meanwhile, pravastatin at ten times higher dose of atorvastatin had no such effects. In cultured myocytes, atorvastatin-related decrease in mitochondrial activity led to a decrease in oxygen utilization and an increase in lactate production. Conversely, coenzyme Q(10) treatment in atorvastatin-treated mice reversed atorvastatin-related mitochondrial dysfunction and a decrease in oxygen utilization, and thus improved exercise endurance. Atorvastatin decreased exercise endurance in mice through mitochondrial dysfunction due to ubiquinone deficiency. Ubiquinone supplementation with coenzyme Q(10) could reverse atorvastatin-related mitochondrial dysfunction and decrease in exercise tolerance.

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MPO-ANCA associated crescentic glomerulonephritis with numerous immune complexes: case report

Morizane, R., Konishi, K., Hashiguchi, A., Tokuyama, H., Wakino, S., Kawabe, H., Hayashi, M., Hayashi, K. and Itoh, H.

BMC Nephrol 13 32 2012.06

ISSN 1471-2369

BACKGROUND: Antineutrophil cytoplasmic antibody (ANCA)-associated crescentic glomerulonephritis (CGN) is a major cause of rapidly progressive glomerulonephritis (RPGN). ANCA-associated CGN is generally classified into pauci-immune RPGN, in which there are few or no immune complexes. CASE PRESENTATION: A 78-year-old man presented with RPGN after a 7-year course of chronic proteinuria and hematuria with stable renal function. A blood examination showed a high titer of myeloperoxidase (MPO)-ANCA. A renal biopsy showed crescentic glomerulonephritis with abundant subepithelial, intramenbranous and subendothelial deposits by electron microscopy, leading to the diagnosis of ANCA-associated CGN superimposed on type 3 membranoproliferative glomerulonephritis (MPGN). CONCLUSIONS: This case is unique in that type 3 MPGN and MPO-ANCA-associated CGN coexisted, and no similar case has been reported to date. Because ANCA-associated CGN has a predilection for elderly individuals and primary type 3 MPGN is rarely seen in this age group, coincidental existence appears less likely. This case may confer valuable information regarding the link between immune complex and ANCA-associated CGN.

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Bile acids induce monocyte differentiation toward interleukin-12 hypo-producing dendritic cells via a TGR5-dependent pathway

Ichikawa, R., Takayama, T., Yoneno, K., Kamada, N., Kitazume, M. T., Higuchi, H., Matsuoka, K., Watanabe, M., Itoh, H., Kanai, T., Hisamatsu, T. and Hibi, T.

Immunology 136 ( 2 ) 153 - 62 2012.06

ISSN 0019-2805

Dendritic cells (DCs) are known as antigen-presenting cells and play a central role in both innate and acquired immunity. Peripheral blood monocytes give rise to resident and recruited DCs in lymph nodes and non-lymphoid tissues. The ligands of nuclear hormone receptors can modulate DC differentiation and so influence various biological functions of DCs. The role of bile acids (BAs) as signalling molecules has recently become apparent, but the functional role of BAs in DC differentiation has not yet been elucidated. We show that DCs derived from human peripheral blood monocytes cultured with a BA produce lower levels of interleukin-12 (IL-12) and tumour necrosis factor-alpha in response to stimulation with commensal bacterial antigens. Stimulation through the nuclear receptor farnesoid X (FXR) did not affect the differentiation of DCs. However, DCs differentiated with the specific agonist for TGR5, a transmembrane BA receptor, showed an IL-12 hypo-producing phenotype. Expression of TGR5 could only be identified in monocytes and was rapidly down-regulated during monocyte differentiation to DCs. Stimulation with 8-bromoadenosine-cyclic AMP (8-Br-cAMP), which acts downstream of TGR5 signalling, also promoted differentiation into IL-12 hypo-producing DCs. These results indicate that BAs induce the differentiation of IL-12 hypo-producing DCs from monocytes via the TGR5-cAMP pathway.

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Novel repressor regulates insulin sensitivity through interaction with Foxo1

Nakae, J., Cao, Y., Hakuno, F., Takemori, H., Kawano, Y., Sekioka, R., Abe, T., Kiyonari, H., Tanaka, T., Sakai, J., Takahashi, S. and Itoh, H.

Embo j 31 ( 10 ) 2275 - 95 2012.05

ISSN 0261-4189

Forkhead box-containing protein o (Foxo) 1 is a key transcription factor in insulin and glucose metabolism. We identified a Foxo1-CoRepressor (FCoR) protein in mouse adipose tissue that inhibits Foxo1's activity by enhancing acetylation via impairment of the interaction between Foxo1 and the deacetylase Sirt1 and via direct acetylation. FCoR is phosphorylated at Threonine 93 by catalytic subunit of protein kinase A and is translocated into nucleus, making it possible to bind to Foxo1 in both cytosol and nucleus. Knockdown of FCoR in 3T3-F442A cells enhanced expression of Foxo target and inhibited adipocyte differentiation. Overexpression of FCoR in white adipose tissue decreased expression of Foxo-target genes and adipocyte size and increased insulin sensitivity in Lepr(db/db) mice and in mice fed a high-fat diet. In contrast, Fcor knockout mice were lean, glucose intolerant, and had decreased insulin sensitivity that was accompanied by increased expression levels of Foxo-target genes and enlarged adipocytes. Taken together, these data suggest that FCoR is a novel repressor that regulates insulin sensitivity and energy metabolism in adipose tissue by acting to fine-tune Foxo1 activity.

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Vaccination against the angiotensin type 1 receptor for the prevention of L-NAME-induced nephropathy

Azegami, T., Sasamura, H., Hayashi, K. and Itoh, H.

Hypertens Res 35 ( 5 ) 492 - 9 2012.05

ISSN 0916-9636

Previous studies have shown that renin-angiotensin (Ang) system vaccines may be effective for the treatment of hypertension, but their efficacy for the prevention of renal disease is unclear. The aim of this study was to compare the effects of an Ang II type 1 (AT1) receptor vaccine with an Ang II receptor blocker (ARB) and a vasodilator on blood pressure (BP) and renal injury in the L-NAME nephropathy model. Male spontaneously hypertensive rats (SHRs) were divided into six groups and treated transiently with three injections of vehicle or AT1 receptor vaccine (0.1 mg) at age 4, 6 and 8 weeks, or continuously with candesartan cilexetil (0.1 mg kg(-1) per day) or hydralazine hydrochloride (5 mg kg(-1) per day), then administered NG-nitro-L-arginine methyl ester (L-NAME) from age 18 to 21 weeks to induce renal injury. Vaccination against the AT1 receptor caused a significant increase in AT1 receptor titers, and a sustained decrease in BP. L-NAME treatment resulted in a marked increase in proteinuria in the control groups, which was completely suppressed in the AT1 vaccine-treated group, and glomerular injury scores were also significantly decreased. Real-time RT-PCR and immunofluorescence studies revealed increased renin mRNA, and increased glomerular expression of nephrin. Comparable results were seen in rats treated continuously with the ARB candesartan, but not with hydralazine. These results suggest that transient AT1 vaccination is as effective as continuous treatment with ARB, not only for the attenuation of hypertension, but also for the prevention of L-NAME-induced nephropathy in SHR.

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Mineralocorticoid receptor-associated hypertension and its organ damage: clinical relevance for resistant hypertension

Shibata, H. and Itoh, H.

Am J Hypertens 25 ( 5 ) 514 - 23 2012.05

ISSN 0895-7061

The role of aldosterone in the pathogenesis of hypertension and cardiovascular diseases has been clearly shown in congestive heart failure and endocrine hypertension due to primary aldosteronism. In resistant hypertension, defined as a failure of concomitant use of three or more different classes of antihypertensive agents to control blood pressure (BP), add-on therapy with mineralocorticoid receptor (MR) antagonists is frequently effective, which we designate as "MR-associated hypertension". The MR-associated hypertension is classified into two subtypes, that with elevated plasma aldosterone levels and that with normal plasma aldosterone levels. The former subtype includes primary aldosteronism (PA), aldosterone-associated hypertension which exhibited elevated aldosterone-to-renin ratio and plasma aldosterone levels, but no PA, aldosterone breakthrough phenomenon elicited when angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin II receptor blocker (ARB) is continued to be given, and obstructive sleep apnea. In contrast, the latter subtype includes obesity, diabetes mellitus, chronic kidney disease (CKD), and polycystic ovary syndrome (PCOS). The pathogenesis of MR-associated hypertension with normal plasma aldosterone levels is considered to be mediated by MR activation by pathways other than high aldosterone levels, such as increased MR levels, increased MR sensitivity, and MR overstimulation by other factors such as Rac1. For resistant hypertension with high plasma aldosterone levels, MR antagonist should be given as a first-line therapy, whereas for resistant hypertension with normal aldosterone levels, ARB or ACE-I should be given as a first-line therapy and MR antagonist would be given as an add-on agent.

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[The 39th scientific meeting: perspectives of internal medicine; the cutting edge of treatment of medical disorders encountered in clinical practice; 10. Summary]

Itoh, H.

Nihon Naika Gakkai Zasshi 101 ( 3 ) 654 - 5 2012.03

ISSN 0021-5384

'Memory' and 'legacy' in hypertension and lifestyle-related diseases

Sasamura, H. and Itoh, H.

Hypertens Res 35 ( 3 ) 272 - 3 2012.03

ISSN 0916-9636

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Regression of atherosclerosis in apolipoprotein E-deficient mice is feasible using high-dose angiotensin receptor blocker, candesartan

Hayashi, K., Sasamura, H., Azegami, T. and Itoh, H.

J Atheroscler Thromb 19 ( 8 ) 736 - 46 2012

ISSN 1340-3478

AIM: Clinical studies have suggested that renin-angiotensin inhibitors are effective for the prevention of atherosclerosis progression, but the results for the regression of established lesions are equivocal. The aim of this study was to examine the effects of different doses of the angiotensin receptor blocker (ARB) candesartan on the regression of atherosclerosis and lipid-induced nephropathy in apolipoprotein E (apoE)-deficient spontaneously hyperlipidemic (SHL) mice. METHODS AND RESULTS: Male SHL were given an atherogenic diet together with salt loading to induce atherosclerosis. The mice were then treated with various doses of candesartan (0-50 mg/kg/d) for 12 weeks. Treatment with high-dose candesartan caused clear regression of atherosclerotic plaques in the aorta, which was not observed with normal-dose candesartan. Biglycan and ACAT1 expression were significantly decreased, and aortic free cholesterol: cholesterol ester ratios were increased in these mice. Treatment of cultured THP-1 macrophages in vitro with candesartan resulted in a similar decrease in ACAT1 expression. In the kidney, glomerular lipid accumulation, mesangial expansion, and albuminuria were significantly regressed after treatment with high-dose candesartan, while biglycan and ACAT1 expressions were decreased. CONCLUSION: These results suggest that regression of established atherosclerosis lesions in ApoE-deficient mice is feasible using high-dose candesartan, by mechanisms involving (i) a decrease in the lipid-retaining proteoglycan biglycan, and (ii) suppression of ACAT1 expression resulting in increased free cholesterol for lipid release.

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