Time filter

Source Type

Nakajima K.,Gunma University | Nakajima K.,Otsuka Pharmaceuticals Co. | Nakajima K.,Kanazawa University | Nakajima K.,University of California at Davis | And 16 more authors.
Clinica Chimica Acta | Year: 2011

Since Zilversmit first proposed postprandial lipemia as the most common risk of cardiovascular disease, chylomicrons (CM) and CM remnants have been thought to be the major lipoproteins which are increased in the postprandial hyperlipidemia. However, it has been shown over the last two decades that the major increase in the postprandial lipoproteins after food intake occurs in the very low density lipoprotein (VLDL) remnants (apoB-100 particles), not CM or CM remnants (apoB-48 particles). This finding was obtained using the following three analytical methods; isolation of remnant-like lipoprotein particles (RLP) with specific antibodies, separation and detection of lipoprotein subclasses by gel permeation HPLC and determination of apoB-48 in fractionated lipoproteins by a specific ELISA. The amount of the apoB-48 particles in the postprandial RLP is significantly less than the apoB-100 particles, and the particle sizes of apoB-48 and apoB-100 in RLP are very similar when analyzed by HPLC. Moreover, CM or CM remnants having a large amount of TG were not found in the postprandial RLP. Therefore, the major portion of the TG which is increased in the postprandial state is composed of VLDL remnants, which have been recognized as a significant risk for cardiovascular disease. © 2011 Elsevier B.V.

Imagawa M.,University of Fukui | Takahashi S.,University of Fukui | Zenimaru Y.,University of Fukui | Kimura T.,University of Fukui | And 9 more authors.
Clinica Chimica Acta | Year: 2012

Background: Comparison of the reactivity of remnant-like lipoprotein particles (RLP) and LDL particles to LDL receptor and VLDL receptor has not been investigated. Methods: LDL receptor- or VLDL receptor-transfected ldlA-7, HepG2 and L6 cells were used. Human LDL and rabbit β-VLDL were isolated by ultracentrifugation. Human RLP was isolated using an immunoaffinity mixed gel. The effect of statin on lipoprotein receptors was examined. Results: Both LDL receptor and VLDL receptor recognized RLP. In LDL receptor transfectants, RLP, β-VLDL and LDL all bound to LDL receptor. Cold RLP competed efficiently with DiI-β-VLDL; however, cold LDL competed weakly. In VLDL receptor transfectants, RLP and β-VLDL bound to VLDL receptor, but not LDL. RLP bound to VLDL receptor with higher affinity than β-VLDL because of higher apolipoprotein E in RLP. LDL receptor expression was induced in HepG2 by the low concentration of statin while VLDL receptor expression was induced in L6 myoblasts at higher concentration. Conclusions: RLP are bound to hepatic LDL receptor more efficiently than LDL, which may explain the mechanism by which statins prevent cardiovascular risk by primarily reducing plasma RLP rather than by reducing LDL. Additionally, a high-dose of statins also may reduce plasma RLP through muscular VLDL receptor. © 2011 Elsevier B.V.

Ikeda T.,Kinki University | Iwanaga Y.,Kinki University | Watanabe H.,Kinki University | Morooka H.,Kinki University | And 3 more authors.
Journal of Cardiovascular Pharmacology | Year: 2015

The effects of chronic blockade of vasopressin type 1a receptors (V1aR) and the additive effects of a type 2 receptor (V2R) antagonist on the treatment of hypertension-induced heart failure and renal injury remain to be unknown. In this study, Dahl salt-sensitive hypertensive rats were chronically treated with a vehicle (CONT), a V1aR antagonist (OPC21268; OPC), a V2R antagonist (tolvaptan; TOLV), or a combination of OPC21268 and tolvaptan (OPC/TOLV) from the prehypertrophic stage (6 weeks). No treatment altered blood pressure during the study. Significant improvements were seen in median survival for the OPC and TOLV, and the OPC/TOLV showed a further improvement in Kaplan-Meier analysis. Echocardiography showed suppressed left ventricular hypertrophy in the OPC and OPC/TOLV at 11 weeks with improved function in all treatment groups by 17 weeks. In all treatment groups, improvements were seen in the following: myocardial histological changes, creatinine clearance, urinary albumin excretion, and renal histopathologic damage. Also, key mRNA levels were suppressed (eg, endothelin-1 and collagen). In conclusion, chronic V1aR blockade ameliorated disease progression in this rat model, with additive benefits from the combination of V1aR and V2R antagonists. It was associated with protection of both myocardial and renal damage, independent of blood pressure. © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Morooka H.,Kinki University | Iwanaga Y.,Kinki University | Tamaki Y.,Kyoto University | Takase T.,Kinki University | And 4 more authors.
Circulation: Heart Failure | Year: 2012

Background-Although recent clinical trials have demonstrated the efficacy of the oral vasopressin (AVP) type 2 receptor (V2R) antagonist tolvaptan, its long-term effects on the myocardium and kidney in heart failure (HF) are not clear. We examined the chronic effects of tolvaptan administration on both the myocardium and kidney in a rat hypertensive HF model. Methods and Results-Not only circulating AVP level but also myocardial AVP and V1a receptor (V1aR) expressions, renal V1aR, and V2R expressions were significantly upregulated during the transition to HF. The animals were chronically treated with low-dose or high-dose (HD) tolvaptan or vehicle from the left ventricular (LV) hypertrophic stage. Chronic tolvaptan treatment persistently increased urine volume but did not affect blood pressure. In the HD group, the animal survival significantly improved (log-rank test, P<0.01). At the HF stage, the progression of LV dysfunction was prevented and lung congestion was suppressed. Activation of atrial natriuretic peptide, endothelin-1, AVP, and V1aR mRNA levels were significantly suppressed in the LV myocardium. Meanwhile, renal histopathologic damage was ameliorated and renal function was improved in the HD group at the HF stage. Concomitantly, not only activation of aquaporin-2 but also those of V2R, V1aR, renin, and endothelin-1 in the kidney were significantly suppressed (all P<0.05). Conclusions-These results indicate that chronic tolvaptan treatment has beneficial effects by preventing not only the progression of LV dysfunction but also that of renal injury in hypertensive rats with HF. The underlying mechanism may be related to the suppression of myocardial and renal neurohumoral activation. © 2012 American Heart Association, Inc.

Maeda M.H.,Japan National Institute of Agrobiological Science | Kondo K.,Otsuka Pharmaceuticals Co.
Journal of Chemical Information and Modeling | Year: 2013

A database of 3D structures of natural metabolites has been developed called 3DMET. During the process of structure conversion from 2D to 3D, we found many structures were misconverted at chiral atoms and bonds. Several popular converters were tested in regard to their conversion accuracy. For verification, three canonical strings were also tested. No procedure could satisfactorily cover all the structures of the natural products. The misconverted structures had to be corrected manually. However, a nonnegligible number of mistakes were also observed even after manual curation, so a self-checking system was developed and introduced to our work flow. Thus, the 3D structures in our 3DMET database were evaluated in two steps: automatically and manually. The current version includes most of the natural products of the KEGG COMPOUND collection [http://www.genome.jp/kegg/compound/] and is searchable by string, value range, and substructure. 3DMET can be accessed via http://www.3dmet.dna.affrc.go.jp/, which also has detailed manuals. © 2013 American Chemical Society.

Loading Otsuka Pharmaceuticals Co. collaborators
Loading Otsuka Pharmaceuticals Co. collaborators