Tetsuto Kanzaki

New indices of ischemic heart disease and aging: studies on the serum levels of soluble intercellular adhesion molecule-1 (ICAM-1) and soluble vascular cell adhesion molecule-1 (VCAM-1) in patients with hypercholesterolemia and ischemic heart disease

It is known that the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on the surface of vascular endothelial cells is closely related to the formation of early atherosclerotic lesions. In this study, serum soluble ICAM-1(sICAM-1) and soluble VCAM-1(sVCAM-1) were determined by sandwich ELISA both in normal healthy individuals (n = 114) and in patients with hypercholesterolemia (HC, n = 112) or ischemic heart disease (IHD, n = 38) to clarify the significance of the soluble forms of the adhesion molecules in the development of atherosclerotic diseases. IHD patients, not HC patients, showed significant elevation of sICAM-1, but not of sVCAM-1, compared with controls in age and sex-matched subjects. In addition, multiple linear regression analysis showed that sICAM-1 was correlated only to the presence of IHD but not to age and lipids. Multiple logistic regression analysis revealed that sICAM-1 was the most powerful independent predictor of the presence of IHD. On the other hand, sVCAM-1, not sICAM-1, was positively correlated to age. Multiple linear regression analysis showed that age was the most powerful independent predictor of the level of sVCAM-1. These data suggest that sICAM-1 and sVCAM-1 are useful as indices of clinical manifestations of atherosclerosis and aging, respectively.

In Vivo Effect of TGF-β1: Enhanced Intimal Thickening by Administration of TGF-β1 in Rabbit Arteries Injured With a Balloon Catheter

Abstract The in vivo effect of transforming growth factor–β1 (TGF-β1) was studied in a model system in which arterial intimal thickening was induced by injury of rabbit arteries with a balloon cath...

Cell cycle-dependent inhibition of DNA synthesis by prostaglandin I2 in cultured rabbit aortic smooth muscle cells

The role of prostaglandin I2 (PGI2) in the control of DNA synthesis during the cell cycle was investigated in cultured rabbit aortic smooth muscle cells (SMC). SMC at confluency in the G0 state reached the S phase about 16 h after stimulation with serum, as judged by measurement of [3H]thymidine incorporation into DNA (DNA synthesis). Cyclooxygenase inhibitors such as indomethacin and aspirin enhanced DNA synthesis, suggesting that endogenously synthesized prostaglandins inhibit DNA synthesis. Added PGE1 or PGE2 had little effect on DNA synthesis. PGI2 inhibited DNA synthesis only when added from 10 to 16 h after stimulation of SMC in the G0 state with serum. Addition of CS-570, a stable PGI2 analogue, inhibited DNA synthesis at any time after serum stimulation. The endogenous syntheses of PGI2 and DNA were negatively correlated. These results suggest that PGI2 inhibits DNA synthesis by acting on the progression stage of the G1 state.

Diabetes mellitus induces accelerated growth of aortic smooth muscle cells: association with overexpression of PDGF β‐receptors

Abstract. The mechanism of diabetic macroangio‐pathy was studied from the view point of phenotypic change of aortic smooth muscle cells (SMC). The growth rates of cultured SMC of diabetic rats or rabbits were higher than those of non‐diabetic animals (controls). This difference of the growth responses was observed specifically with platelet‐derived growth factor (PDGF). Of the three PDGF dimers, PDGF‐AB heterodimer (PDGF‐AB) and PDGF‐BB homodimer (PDGF‐BB) stimulated growth of diabetic SMC more than that of control SMC but PDGF‐A A homodimer (PDGF‐AA) did not. The binding of ′251‐PDGF to the diabetic SMC was greater than that to control SMC. This was due to increase in the number of cell surface receptors for PDGF. On in vitro culture, SMC from diabetic rats expressed more PDGF β‐receptor mRNA than SMC from non‐diabetic rats. Moreover, in vivo, the aortic media of diabetic rabbits expressed PDGF β‐receptor mRNA, but that from non‐diabetic rabbits did not. Thus diabetic SMC over‐react on PDGF stimulation through over‐expression of the PDGF P‐receptor gene. The significance of this fact in development of diabetic macroangiopathy is discussed.

Mechanism of angiogenic effects of saponin from ginseng Radix rubra in human umbilical vein endothelial cells.

1 The effects of saponin from Ginseng Radix rubra on angiogenesis (tube formation) and its key steps (protease secretion, proliferation and migration) in human umbilical vein endothelial cells (HUVEC) were examined to elucidate the mechanism of the tissue repairing effects of Ginseng Radix rubra. The effect on a wound healing model was also studied. 2 Tube formation was measured by an in vitro system. The activity and immunoreactivity of tissue‐type plasminogen activator (tPA) as a protease for angiogenesis and the immunoreactivity of its inhibitor, plasminogen activator inhibitor‐1 (PAI‐1), were measured in conditioned medium of HUVEC stimulated for 24 h with saponin. Cell proliferation was measured by counting the cell numbers at 2–7 days after seeding. Migration was measured by Boydens chamber method. The effect on wound healing was studied in the skin of diabetic rats. 3 Saponin at 10–100 μg ml−1significantly stimulated tube formation by HUVEC in a dose‐dependent manner. Saponin in a similar concentration‐range increased the secretion of tPA from HUVEC as estimated by immunoreactivity and enzyme activity. On the other hand, PAI‐1 immunoreactivity was slightly increased at 10 44μg ml−1 of saponin, but then was significantly decreased at 50 and 100 μg ml−1. Cell proliferation was only slightly enhanced by 1–100 μg ml−1 of saponin, but migration was significantly enhanced by 10–100 μg ml−1 in a dose‐dependent manner. Moreover, saponin stimulated wound healing with enhanced angiogenesis in vivo. 4 These results indicate that saponin stimulates tube formation mainly by modifying the balance of protease/protease inhibitor secretion from HUVEC and enhancing the migration of HUVEC, and that it is effective in vivo.

Enhanced arterial intimal thickening after balloon catheter injury in diabetic animals accompanied by PDGF β-receptor overexpression of aortic media

Abstract. Cultured aortic smooth muscle cells (SMC) of diabetic rats and rabbits, which overexpress platelet‐derived growth factor (PDGF) β‐receptor compared with controls, have a unique phenotype. In this study we report on the PDGF β‐receptor overexpression in aortas of diabetic animals and the increased intimal thickening of carotid arteries in diabetic rabbits after balloon catheter injury compared with that in controls. In diabetic aortas with no treatments of balloon catheter injury, intimal thickening was not observed in spite of the overexpression of PDGF β‐receptor, indicating that the growth property of medial SMC in diabetic aortas was changed before the intimal thickening could take place. PDGF is known to be the main contributor to the intimal thickening induced by balloon catheter injury, which is one of several forms of arterial injuries. Intimal thickening after balloon catheter injury in diabetic rabbits increased compared with that in controls. These results imply that PDGF β‐receptor overexpression of SMC in medial layers plays an important role in intimal thickening in the formation of advanced diabetic macroangiopathy.

Diabetic Control and Progression of Retinopathy in Elderly Patients: Five‐Year Follow‐up Study

Objective: To assess whether control of diabetes mellitus is as important in the elderly as in young and middle‐aged diabetic patients in terms of progression of retinopathy.

Serotonin (5-hydroxytryptamine, 5-HT) enhances migration of rat aortic smooth muscle cells through 5-HT2 receptors

The effects of serotonin on migration of cultured rat aortic smooth muscle cells (SMC) were studied to clarify the role of this substance in the pathogenesis of atherosclerosis. Serotonin alone did not stimulate SMC migration but stimulated it at physiological concentrations in the presence of other migration factors such as SMC-derived migration factor, platelet-derived migration factor and fibronectin. Checker-board analysis revealed that the serotonin effect was chemotactic. Moreover, serotonin effects were completely abolished by a selective inhibitor of the 5-HT2 receptor (MCI-9042), indicating that serotonin effects were mediated through the 5-HT2 receptor pathway. Finally, serotonin effects were also abolished by a phospholipase C inhibitor, U73122, suggesting that the 5-HT2 receptor mediated signal of serotonin was transduced by PLC. The results suggest that platelet-derived serotonin plays some role in the SMC dominant neointima formation.

Correlation between images of silent brain infarction, carotid atherosclerosis and white matter hyperintensity, and plasma levels of acrolein, IL-6 and CRP

OBJECTIVE We found previously that the measurement of plasma levels of protein-conjugated acrolein (PC-Acro) together with IL-6 and CRP can be used to identify silent brain infarction (SBI) with high sensitivity and specificity. The aim of this study was to clarify how three biochemical markers are correlated to SBI, carotid atherosclerosis (CA) and white matter hyperintensity (WMH). METHODS The levels of PC-Acro, IL-6 and CRP in plasma were measured by ELISA. SBI and WMH were evaluated by MRI, and CA was evaluated by duplex carotid ultrasonography. RESULTS A total of 790 apparently healthy volunteers were classified into 260 control, 214 SBI, 263 CA and 245 WMH subjects, which included 187 subjects with two or three pathologies. When the combined measurements of PC-Acro, IL-6 and CRP were evaluated together with age, using a receiver operating characteristic curve and artificial neural networks, the relative risk value (RRV), an indicator of tissue damage, was in the order SBI with CA (0.90)>SBI (0.80)>CA (0.76)>WMH with CA (0.65)>WMH (0.46)>control (0.14). RRV was also correlated with severity in each group of SBI, CA and WMH. CONCLUSION The RRV supports the idea that the degree of risk to develop a stroke is in the order SBI>CA>WMH.

Dose-dependent hypolipidemic effect of an inhibitor of HMG-CoA reductase, pravastatin (CS-514)) in hypercholesterolemic subjects A double blind test

The hypolipidemic effect of a new HMG-CoA reductase inhibitor, pravastatin, was examined. The reductions of serum cholesterol and LDL-cholesterol were dose-dependent and significant differences were observed between placebo and 10 or 20 mg groups (P less than 0.01), and 10 and 20 mg (P less than 0.05) groups. The reduction rate of cholesterol after 8 weeks during medication was 16.1% in the 10 mg group, 20.5% in the 20 mg group compared to baseline serum cholesterol levels. LDL-cholesterol decreased by 23.9% in the 10 mg group, and 29.8% compared to baseline LDL-cholesterol in the 20 mg group. The lowering of total cholesterol was entirely attributed to a reduction in LDL-cholesterol.