One of the most important factor of thrombosis and atherogenesis is intimal injury. We examined the morphology of intimal injury (denuding and non-denuding) and intimal thickening in the rabbit aorta.
I. Denuding injury: When the intima was injured by polyethylene tubuing, we observed adhesion of platelets on the denuded area with various degrees of aggregation. The internal elastic lamina (TEL) was well preserved in the injured site. Then the raised thrombi were organized and became into the focal fibrocellular intimal thickening. On the other hand, a balloon catheter induced the various degree of aortic injury. When the injury was limited in the intima, the following intimal thickening was very similar to that by polyethylene tubing. However, the injury extended into the media, interruption of the TEL and necrosis of smooth muscle cells in the media were observed, and the following intimal thickening was rather mild. The second injury onto the thickened intima developed large thrombi composed of prominent fibrin and aggregated platelets, and induced markedly thickened intima.
II. Non-denuding injury: Materials released from the mural white thrombi induced the endothelial cell damage and ensuing replication of endothelial cells and smooth muscle cells at the inner portion of the media. With the time, the fibrocellular intimal thickening was also induced.
These findings demonstrate that the intimal thickening is dependent on the degree and duration or repetition of the injury, and the components of the subendothelial tissue.

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At the branch of the inferior mesenteric artery in the human adult aorta, we found that the intima of apex, which was exposed to a laminal high shear stress, showed less prominent thickening and more resistance to atherogenesis than the lateral wall, which was exposed to a low shear stress. We therefore investigated the effects of shear stress on the biological function of endothelial cells whose change influences subendothelial smooth muscle cell functions, leading to compositional differences between the apical intima and that of the lateral wall. Confluent, cultured, bovine, aortic-endothelial cells (EC) were exposed to a steady laminal flow with a relatively high shear stress (30dyn/cm²) in a parallel plate flow chamber. DNA synthesis, assayed by ³H-thymidine uptake of EC exposed to shear stress for 24 hours, decreased significantly (27% of the control). Entry into the S phase, analyzed by flow cytometry, was concomitantly inhibited by the shear stress. Platelet-derived growth factor (PDGF) B mRNA was expressed within 3 hours, increased until 6 hours, and was then sustained for 24 hours. Phorbol 12-myristate 13-acetate, a well known protein kinase C (PKC) activator, induced PDGF B mRNA in our EC. However 1-oleoyl-2-acetyl-sn-glycerol, a selective PKC activator, did not induce PDGF B mRNA expression. Furthermore, down-regulation by phorbol 12, 13 dibutyrate or exposure to staurosporine failed to block flow-induced PDGF B mRNA expression. These results indicate that activation of PKC alone may not be sufficient to cause flow-induced PDGF B mRNA expression. cAMP, increased by forscolin, inhibited shear-stress induced PDGF B mRNA expression. Our findings suggest that mechanical flow signals are transmitted to EC nuclei, and the flow's alteration of the biological character of EC may be important in an individual's resistance or susceptibility to vascular diseases such as atherosclerosis.

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Percutaneous transluminal coronary angioplasty (PTCA) has become widely accepted as the preferred treatment for selected patients with acutely or chronically obstructed coronary arteries. Pathological observations of human coronary arteries after PTCA have suggested that arterial-wall and plaque injuries are the primary mechanisms of dilation in PTCA. The present study focused on cellular reactions at the angioplasty injury site in autopsied patients who had died after being subjected to PTCA.
Seventy-one hearts including 106 PTCA sites were available for this study. The interval between PTCA and death at these sites varied from three hours to three years and three months. The localization of the angioplasty site was determined by correlation between the specimens and the angiograms taken when the procedure was carried out. The coronary arteries subjected to the angioplasty were sectioned serially at 1-mm intervals and examined. To conduct immunocytochemical investigations, the following monoclonal antibodies were used: antimuscle actin antibody, HHF 35; anti-smooth muscle actin antibody, CGA 7 ; anti-vimentin antibody; anti-desmin antibody; anti-macrophage antibody, HAM 56; anti-factor VIII-related antigen antibody.
All the dilated sites revealed an angioplasty injury of the coronary arterial wall. In cases of a medial angioplasty injury, the earliest cellular response was observed 5 days after PTCA, and was characterized by de-differentiation of the medial smooth muscle cells and the appearance of spindle-shaped cells at the injury site. At the earliest stage, the cells in the reactive tissue failed to express smooth muscle cell actin. However, during evolution of the reactive tissue, re-differentiation of smooth muscle cells occurred, as revealed by changes in the actin expression. Injury to an atheroma caused a different type of cellular response. At these sites, plaque hemorrhage often dominated the lesion, resulting in a proliferation of organization tissue. Immunocytochemical staining showed that the repair tissue at the atheroma injury site was composed of macrophages, smooth muscle cells and small vessels.
These findings indicate that in the cellular response that followed angioplasty injury of a human coronary artery: 1) spindle-shaped cells within the reactive tissue at the earliest stage reveal cytoskeletal features consistent with a de-differentiated smooth muscle cell phenotype; 2) during evolution of the reactive tissue, smooth muscle cells revert to cytoskeletal features reflecting re-differentiation.

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This study offers an immunohistochemical analysis of the coordinate localization of the PDGF B-chain and its specific receptor, the PDGFβ-receptor subunit, in the different stages of atherogenesis in the aortas of cholesterol-fed nonhuman primates. Smooth muscle cells and macrophages in the cell cycle were investigated in the adjacent sections of these lesions to evaluate the possible role of PDGF in this process. Intense staining of PDGF β-receptor was distributed in a-Actin positive cells [smooth muscle cells (SMCs)] in the intima and innermost medial layers through all phases of atherogenesis. These receptor-positive SMCs were distributed in close proximity to macrophages containing the PDGF B-chain protein. Lesions containing numerous PCNA-positive cells tended to show intense staining for the PDGF B-chain. PCNA-positive cells in intimal lesions at all stages of development consisted of 44.5% macrophages (HAM-56 positive), and 25.5% SMCs, while 31% were undefined. A substantial number of PCNA-positive SMCs in fatty streaks were also distributed in the first few layers of the media just under the lesion. Numerous SMCs appeared to form perpendicular arrays protruding from the media into the intima. These results suggest that SMC accumulation in the lesions may be mediated by their migration from the media into the intima, as well by their proliferation within the intima. Thus, there is an increased expression of both the PDGF B-chain in macrophages and PDGF β-receptor subunits in SMCs at the sites of developing lesions that are enriched by infiltrating and proliferating SMCs.

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We studied serum lipoprotein (a) (Lp (a)) levels in 48 Japanese children with insulin-dependent-diabetes mellitus (IDDM). The subjects were on average 12.5±0.6 (SEM) years old, the duration of diabetes was 4.3±0.5 years, the insulin was 1.05±0.05U/kg, and the HbAlc was 7.91±0.22%. Serum Lp (a) was 16.7±2.6mg/dl (range, 0.6∼66.5mg/dl), the geometric mean level of Lp (a) was 9.2mg/dl, and 27.1% of the patients had Lp (a) levels that were more than 17mg/dl. Serum Lp (a) was not related to fasting plasma glucose, plasma fructosamine or HbAlc. Furthermore, serum Lp (a) was not significantly related to age, gender, duration, body mass index, urinary C-peptide or albumin excretions. Serum Lp (a) was not related to fasting plasma glucose, plasma fructosamine or HbAlc. However, serum Lp (a) was significantly related to the atherogenic index, apolipoprotein B/A1 (p<0.05), and apolipoprotein B (p<0.005). These results indicat that serum Lp (a) levels in Japanese children with IDDM do not differ from the values for normal children reported in the literature.

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The purposes of the present study were to evaluate the obesity, physical fitness, smoking, and alcohol intake as independent predictors of sex hormones and/or sex hormone binding globulin (SHBG), and to investigate the relationships of lipid and glucose metabolism with above various markers in healthy men, The participants in this study were healthy men aged 18 to 59 years (n=235). SHBG was significantly correlated with age (r=0.42) and body mass index (BMI; r=-0.24), but was not correlated with waist-hip ratio (WHR) and estimated maximal oxygen uptake (VO₂max). Multiple linear regression analysis demonstrated that SHBG was independently associated with age and BMI. Simple correlation analysis showed that SHBG was positively related to total cholesterol (TC ; r=0.18; p<0.05), HDL-C (r=0.17; p<0.05), and LDL-C (r=0.14; p<0.05), and negatively related to fasting insulin (IRI; r=-0.261; p<0.05). SHBG, triglyceride and fasting blood glucose (FBS) were not related. Multiple linear regression analysis indicated that SHBG was one of the determinants of HDL-C levels, but not IRI. These results suggest that SHBG is one of the determinants of HDL-C levels in healthy men.

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Adipose tissue distribution is an improtant atherosclerosis risk factor. The effect of adipose tissue distribution on blood pressure (BP) and cardiac performance during physical exercise has not been clearly demonstrated. In this paper adipose tissue ditribution in non-obese (BMI 23.1±1.3; Age 57.7±12.1yrs; N=32) obese (BMI 31.7±2.1; Age 59.7±10.1yrs; N=19) subjects was compared by CT, glucose tolerance, blood pressure and double product (DP: HR×SBP) in the treadmill stress test. The visceral fat area at the navel level (V) was 100.8±34.0cm² in the non-obese (C) group, and 131.3±44.7cm² in the obese (O) group (p<0.01). Subcutaneous adipose tissue areas at the navel level (S) were 134.1±65.5cm² in the C group and 281.6±65.2cm² in the O group (p<0.01). V/S ratios were 1.20±1.4 in the C group and 0.47±0.18 in the group (p<0.05). Therefere, S was more markedly increased than V in O group. Plasma fasting TC, TG, HDL-C, apoA1, apoB, glucose and UA levels in the 2 groups were not statistically different. Plasma glucose levels were 104.5±17.9mg/dl in the C group and 110.8±26.7mg/dl in the O group before 75 gOGTT (NS) and 175.6±58.7mg/dl in the C group and 157.7±60.2mg/dl in the O group at 120min (NS). Plasma IRI levels were 7.7±3.1μU/mi in the C group and 13.7±6.2 μU/ml in the o group before OGTT (p<0.02), and 69.3±61.7μU/ml in the C group and 127.0±95.6μU/ml in the O group at 120min (p<0.05).
SBPs were 158.4±20.2mmHg at stage 1 of the treadmill stress test with a Bruce protocol, 174.8±23.9mmHg at stage 2, and 188.1±23.1mmHg at stage 3 in the C group. SBPs were 190.1±31.7mmHg at stage 1, 209.5±22.2mmHg at stage 2, and 235.4±31.9mmHg at stage 3 in the O group. DPs were 16880±3898 at stage 1, 21510±4108 at stage 2, and 26070±4225 at stage 3 in the C group. DPs were 21847±5539 at stage 1, 28086±4958 at stage 2, and 34136±6630 at stage 3 in the O group. Therefore, SBPs and DPs were obviously higher at all stages in the O group in the C group (p<0.01).
We therefore concluded that obese subjects had high insulin levels, high SBP and high DP during physical exercise probably due to an increase in the total adipose tissue mass, rathar than due to an increase in the visceral adipose tissue mass.

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It is well known that probucol has an antioxidant property and that it inhibits LDL oxidation. Nevertheless, it was reported that when measured by the TBA method the administration of probucol increased serum lipid peroxide. In this study, the effect of probucol on the measurement of lipid peroxide, using the TBA method in particular, was examined. Adding probucol to serum increased the TBA reactive substance (TBARS) in a concentration-dependent manner, but did not affect lipid hydroperoxide by the method with methylene-blue derivative; the greater the volume of serum taken, the higher the TBARS concentration that was found in the presence of probucol. The increased TBAR was dependent on the concentration of probucol in the TBA reaction mixture, but independent of the concentration of probucol in the serum. Furthermore, TBARS values were greatly affected by a lower pH in the presence of probucol. These results suggest that the TBA method overstimates lipid peroxide in serum that contains probucol. Therefore, special care is required when TBARS is used as an index of lipid peroxide in biological samples.

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