Hidehiko Waki

Osaka Police Hospital, Ōsaka, Ōsaka, Japan

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Publications (7)22.29 Total impact

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    ABSTRACT: We attempted to test the hypothesis that chronic angiotensin II type 1A receptor blockade (ARB) alters myocardial collagen turnover leading to an improvement of diastolic dysfunction in diabetic patients. Forty-eight type 2 diabetic patients were divided into 2 groups: 38 treated with candesartan for 6 months, and 10 without candesartan, as controls. Doppler mitral flow velocity pattern and biomarkers of collagen type I turnover were assessed before and after ARB during a 6-month period. The mitral E/A ratio increased from 0.65+/-0.11 to 0.75+/-0.19. The carboxy-terminal propeptide of procollagen type I (PIP), an index of collagen type I synthesis, decreased and the carboxy-terminal telopeptide of collagen type I (CITP), an index of collagen type I degradation, increased following ARB. Consequently, the PIP/CITP ratio, an index of coupling between the synthesis and degradation of collagen type I, decreased. None of the indexes changed in the control group. The change in left ventricular chamber stiffness did not correlate with the change in PICP (r=0.08, p=NS), but it did with the changes in CITP or in the PIP/CITP ratio (r=0.35, p<0.05; r=0.39, p<0.05). Chronic ARB improves diastolic dysfunction in diabetic patients, at least partially through the attenuation of myocardial fibrosis, by regulating collagen turnover, particularly by facilitating collagen degradation.
    No preview · Article · May 2007 · Circulation Journal
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    ABSTRACT: Background We attempted to test the hypothesis that chronic angiotensin II type 1A receptor blockade (ARB) alters myocardial collagen turnover leading to an improvement of diastolic dysfunction in diabetic patients. Methods and Results Forty-eight type 2 diabetic patients were divided into 2 groups: 38 treated with candesartan for 6 months, and 10 without candesartan, as controls. Doppler mitral flow velocity pattern and biomarkers of collagen type I turnover were assessed before and after ARB during a 6-month period. The mitral E/A ratio increased from 0.65±0.11 to 0.75±0.19. The carboxy-terminal propeptide of procollagen type I (PIP), an index of collagen type I synthesis, decreased and the carboxy-terminal telopeptide of collagen type I (CITP), an index of collagen type I degradation, increased following ARB. Consequently, the PIP/CITP ratio, an index of coupling between the synthesis and degradation of collagen type I, decreased. None of the indexes changed in the control group. The change in left ventricular chamber stiffness did not correlate with the change in PICP (r=0.08, p=NS), but it did with the changes in CITP or in the PIP/CITP ratio (r=0.35, p<0.05; r=0.39, p<0.05). Conclusions Chronic ARB improves diastolic dysfunction in diabetic patients, at least partially through the attenuation of myocardial fibrosis, by regulating collagen turnover, particularly by facilitating collagen degradation. (Circ J 2007; 71: 524 - 529)
    No preview · Article · Jan 2007 · Circulation Journal

  • No preview · Article · Jan 2006 · Choonpa Igaku

  • No preview · Article · Jan 2006 · Atherosclerosis
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    ABSTRACT: This study was conducted to examine whether tissue characterization of the carotid artery wall by determining integrated backscatter (IBS) can identify subjects with a recent history of acute coronary syndrome (ACS) or atherothrombotic infarction (ATI). The maximum thickness (Max-IMT) and IBS value (corrected-IBS) of the carotid artery intima-media complex were measured ultrasonographically for 132 type 2 diabetic subjects (62.9+/-8.5 (+/-S.D.) years old, 87 men and 45 women) with or without cardiovascular diseases. The diabetic patients with recent ACS or ATI had a significantly lower corrected-IBS and higher Max-IMT than those with Max-IMT > or = 1.1mm but without cardiovascular diseases. The product of Max-IMT and corrected-IBS (IMT-IBS product) of the patients with recent ACS was significantly lower than that of the patients with chronic stable angina. The multiple logistic model showed that only the IMT-IBS product was associated with a recent history of ACS (odds ratio 0.94, P<0.05) and ATI (odds ratio 0.90, P<0.005). Diabetic patients who had a recent history of ACS or ATI showed a lower IBS value and higher IMT for their carotid artery. Both the size and tissue characteristics of the carotid plaque may identify subjects with a high risk of cardiovascular disease.
    No preview · Article · Feb 2004 · Diabetes Research and Clinical Practice
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    ABSTRACT: Histological abnormalities of the atherosclerotic lesion are closely related to the stability of the plaque. Specifically, the plaque is likely to be unstable if the fibrous cap is thin. However, ultrasonic characterization of the atherosclerotic lesion has not been done from this viewpoint. Thus, in the present study ultrasonic tissue characterization of the carotid atherosclerotic lesion was attempted to assess the stability of the plaque. Integrated ultrasonic backscatter (IBS) in the atherosclerotic lesion was compared with histological findings of the respective tissue in 35 patients with carotid artery stenosis who underwent carotid endarterectomy. Carotid IBS was determined by locating the region-of-interest (ROI) in the center of the atherosclerotic lesion and calibrating by subtracting the IBS in the tunica externa of the vessel from the IBS of the ROI. IBS was also determined at the interface of the plaque, and at this site it was analyzed in relation to the thickness of the fibrous cap. Lipid content, fibrous tissue, thrombus, hemorrhage and calcification were histologically assessed in the respective tissue. Carotid IBS in the lipid lesion (-22.5 +/- 4.1 dB) was significantly different from that of fibrous, hemorrhagic or calcified lesions (-11.1 +/- 7.1, -27.5 +/- 4.1, +2.1 +/- 6.5 dB, respectively), but there was no significant difference in IBS between the lipid lesion and thrombus (-15.2 +/- 8.8 dB). IBS was lower in the thin fibrous cap than in the thick lesion (-10.9 +/- 6.4 vs -2.4 +/- 6.2 dB, p<0.001). IBS can be used to characterize atherosclerotic lesions in the carotid artery; a low value at the interface suggests a thin fibrous cap, which is frequently associated with unstable plaque.
    No preview · Article · Dec 2003 · Circulation Journal
  • [Show abstract] [Hide abstract]
    ABSTRACT: Histological abnormalities of the atherosclerotic lesion are closely related to the stability of the plaque. Specifically, the plaque is likely to be unstable if the fibrous cap is thin. However, ultrasonic characterization of the atherosclerotic lesion has not been done from this viewpoint. Thus, in the present study ultrasonic tissue characterization of the carotid atherosclerotic lesion was attempted to assess the stability of the plaque. Integrated ultrasonic backscatter (IBS) in the atherosclerotic lesion was compared with histological findings of the respective tissue in 35 patients with carotid artery stenosis who underwent carotid endarterectomy. Carotid IBS was determined by locating the region-of-interest (ROI) in the center of the atherosclerotic lesion and calibrating by subtracting the IBS in the tunica externa of the vessel from the IBS of the ROI. IBS was also determined at the interface of the plaque, and at this site it was analyzed in relation to the thickness of the fibrous cap. Lipid content, fibrous tissue, thrombus, hemorrhage and calcification were histologically assessed in the respective tissue. Carotid IBS in the lipid lesion (-22.5+/-4.1 dB) was significantly different from that of fibrous, hemorrhagic or calcified lesions (-11.1+/-7.1, -27.5+/-4.1, +2.1+/-6.5 dB, respectively), but there was no significant difference in IBS between the lipid lesion and thrombus (-15.2+/-8.8 dB). IBS was lower in the thin fibrous cap than in the thick lesion (-10.9+/-6.4 vs -2.4+/-6.2 dB, p<0.001). IBS can be used to characterize atherosclerotic lesions in the carotid artery; a low value at the interface suggests a thin fibrous cap, which is frequently associated with unstable plaque.
    No preview · Article · Dec 2003 · Circulation Journal