A decrease in high density lipoprotein-cholesterol (HDL-C) is a strong risk factor for atherosclerotic disorders in Japan, probably more important than an increase in low density lipoprotein-cholesterol (LDL-C). While there are rational grounds for the argument that elevation of HDL-C leads to decreased risk, there has as yet been no direct evidence of such an effect. If elevation of HDL-C decreases the risk, this effect is expected throughout the normal range of HDL-C or perhaps even higher than that. Simulation based on epidemiological data indicated that it may eventually reduce the incidence of ischemic heart disease by 60-70% in Japan. In the risk management guideline, “low” HDL-C is presently defined as 40 mg/dL or below. While there is no evidence that strongly urges a change in this definition, the results of epidemiological studies support “The higher the HDL-C level, the lower the risk,”even in the “normal range”. Elevation of the HDL-C level may reduce the risk, probably at least up to 70 mg/dL; however, there are no supportive data for this effect still being obtained over 80 mg/dL. Patients with homozygous CETP deficiency should be followed-up while controlling other risk factors, so as not to dismiss the possibility of a risk increase with an extremely elevated HDL-C level.
Aim: Existing evidence suggests that endothelial lipase (EL) plays an important role in high-densitylipoprotein (HDL) metabolism. Because rabbits are a useful animal model for the study of human lipid metabolism and atherosclerosis, we characterized rabbit EL (rEL) expression and investigated its relationship with plasma HDL levels in normal and hyperlipidemic rabbits. Methods: We cloned the rEL cDNA and analyzed the EL tissue expression using Northern blotting, real-time RT-PCR, Western blotting, and in situ hybridization. We evaluated the effects of rEL antisense on plasma HDL levels. Results: We found that rEL mRNA was highly expressed in cholesterol synthesis-related organs, including the liver, testis, and adrenal along with its expression in the lung, kidney, bone marrow, and small intestine. Interestingly, Watanabe heritable hyperlipidemic (WHHL) rabbits, a model of human familial hypercholesterolemia, had lower plasma levels of HDLs than normal rabbits. The plasma HDL levels in WHHL rabbits were inversely associated with high levels of plasma rEL proteins and hepatic expression of rEL mRNA. Injection of rEL-specific antisense oligonucleotides into rabbits resulted in the elevation of plasma large HDLs. Furthermore, we demonstrated that rEL mRNA was expressed by both endothelial cells and macrophages in the lesions of aortic atherosclerosis of WHHL rabbits. Conclusions: rEL is expressed in multiple tissues and may have many physiological and pathophysiological functions, such as in the regulation of cholesterol metabolism and atherosclerosis. Our results suggest that EL is an important regulator of plasma HDL levels in rabbits.
Aim: Menopause and subsequent estrogen deficiency correlate with the development of atherosclerosis and cardiovascular diseases in women. However, the relationship between estrogen deficiency and development of atherosclerosis with inflammatory infiltrates is not fully understood. We sought to determine whether perimenopausal women (PMW) exhibited T cell dysfunction related to the expression of adhesion molecules and accelerated endothelial cell (EC) apoptosis. Methods: Fresh CD4 T cells were isolated from 48 PMW and 54 healthy control women with regular menstrual cycles (CW), and investigated cytotoxicity to ECs by apoptosis assay. The adhesion molecules on CD4 T cells were examined by flow cytometry. CD4 T cell rolling and adhesion on ECs were analyzed by adhesion assay under laminar flow. Results: CD4 T cells from PMW with low estradiol levels induced significant EC apoptosis (P = 0.0152). Furthermore, cytotoxic CD4 T cells from PMW strongly expressed P-selectin glycoprotein ligand-1 (PSGL-1) and integrin β2 (P < 0.0001 and P = 0.0285, respectively) but not L-selectin or integrin αM when compared to CD4 T cells from CW. Estradiol levels negatively correlated with only PSGL-1 expression (R = −0.781, P = 0.0002), and estradiol treatments inhibited both PSGL-1 expression (P = 0.0133) and T cell-induced EC apoptosis (P = 0.018). An estrogen receptor antagonist inhibited these effects of estradiol (P = 0.0355 and P = 0.0097, respectively). Moreover, PSGL-1 expression correlated with T cell adhesion to ECs under laminar flow conditions (R = 0.636, P = 0.0355) and with EC apoptosis (R = 0.614, P = 0.0196). PSGL-1 specific antibodies effectively suppressed T cell adhesion (P = 0.0057) and EC apoptosis (P = 0.001) indicating that CD4 T cell-mediated EC apoptosis depended on PSGL-1 adhesion in PMW. Conclusions: PSGL-1-expressing cytotoxic CD4 T cells are abundant in PMW with low estradiol levels may contribute to T cell-mediated atherosclerotic development.
Aim: Euterpe Oleracea (açai) is a fruit from the Amazon region whose chemical composition may be beneficial for individuals with atherosclerosis. We hypothesized that consumption of Euterpe Oleracea would reduce atherosclerosis development by decreasing cholesterol absorption and synthesis. Methods: Male New Zealand rabbits were fed a cholesterol-enriched diet (0.5%) for 12 weeks, when they were randomized to receive Euterpe Oleracea extract (n = 15) or water (n = 12) plus a 0.05% cholesterol-enriched diet for an additional 12 weeks. Plasma phytosterols and desmosterol were determined by ultra-performance liquid chromatography and mass spectrometry. Atherosclerotic lesions were estimated by computerized planimetry and histomorphometry. Results: At sacrifice, animals treated with Euterpe Oleracea had lower levels of total cholesterol (p =0.03), non-HDL-cholesterol (p = 0.03) and triglycerides (p = 0.02) than controls. These animals had smaller atherosclerotic plaque area in their aortas (p = 0.001) and a smaller intima/media ratio (p = 0.002) than controls, without differences in plaque composition. At the end of the study, campesterol, β-sitosterol, and desmosterol plasma levels did not differ between groups; however, animals treated with Euterpe Oleracea showed lower desmosterol/campesterol (p = 0.026) and desmosterol/ β-sitosterol (p =0.006) ratios than controls. Conclusions: Consumption of Euterpe Oleracea extract markedly improved the lipid profile and attenuated atherosclerosis. These effects were related in part to a better balance in the synthesis and absorption of sterols.
Aim: It remains uncertain whether chronic exposure to particulate air pollution is associated with increased mortality in Japan because Japan has a different distribution pattern of cardiovascular disease and its risk factors compared to Western countries. We investigated the association between long-term exposure to particulate matter (PM) and cardiovascular mortality risk using a representative Japanese cohort. Methods: A total of 7,250 participants aged 30 years and older from 232 districts throughout Japan were followed from 1980 to 2004. We linked the averaged annual concentrations of PM from 1985 to 2004 to each cohort participant who resided in the district at the time of the baseline survey. Study participants were divided into quintiles of average PM concentration. We applied the Cox proportional hazard model adjusting for sex, age, body mass index, blood pressure, total cholesterol, blood glucose, smoking categories, drinking categories, and the municipality population size. Results: During follow-up, there were 1,716 deaths from all causes; 571 from cardiovascular disease, 116 from coronary heart disease, and 250 from stroke. Hazard ratios were not different among the quintiles and those for trend per 10 µg/m3 increase in annual PM concentration were 0.98 (95% confidence interval, 0.92-1.04) for all-cause mortality and 0.90 (95% confidence interval, 0.81-1.00) for cardiovascular mortality. Conclusion: Long-term exposure to PM was not associated with increased cardiovascular mortality risk in this population-based cohort in Japan.
Aims: Plasma brain natriuteric peptide (BNP) is an established marker of cardiovascular events in individuals without heart failure. Although the cardio-ankle vascular index (CAVI) is clinically used as a parameter of arterial stiffness, its usefulness for predicting cardiovascular events has not been fully examined. This study aimed to evaluate the association among CAVIs, plasma BNP levels and left ventricular (LV) hypertrophy and dysfunction in hypertensive patients. Methods: We enrolled 136 hypertensive patients (69±10 years) who had been taking antihypertensive medications for at least one year. Echocardiography was performed to evaluate LV hypertrophy and function. Plasma BNP levels and CAVIs were also measured simultaneously. Results: CAVI was correlated with plasma BNP (r =0.245, p =0.004). Multiple linear regression analysis revealed three independent determinants of CAVI: age (β =0.568, p <0.001), diameter of ascending aorta (β =0.289, p <0.001), and diabetes (β =0.207, p =0.003). In addition, multiple linear regression analysis revealed two independent determinants of the plasma BNP level: left atrial diameter (β =0.334, p <0.001) and CAVI (β =0.256, p =0.002). Conclusion: The present study indicates that increased CAVI is independently associated with elevated plasma BNP produced by increased LV afterload, that is, arterial stiffness, in hypertensive patients. Moreover, the present study raises the possibility that CAVI may be as useful as the plasma BNP level for predicting the risk of cardiovascular events in hypertensive patients.
Aim: The clustering of dyslipidemia, impaired glucose tolerance and hypertension increases the morbidity and mortality from cardiovascular events. A class B scavenger receptor, CD36, is a receptor for oxidized LDL and a transporter of long-chain fatty acids. Because of the impaired uptake of oxidized LDL in CD36-deficient macrophages and from the results of CD36 knockout mice, CD36 deficiency (CD36-D) was supposed to be associated with reduced risks for coronary artery disease (CAD); however, CD36-D patients are often accompanied by a clustering of coronary risk factors. The current study aimed to investigate the morbidity and severity of cardiovascular diseases in CD36-D patients. Methods: By screening for CD36 antigen on platelets and monocytes using FACS or the absent myocardial accumulation of 123I-BMIPP by scintigraphy, 40 patients with type I CD36-D were collected, the morbidity of CAD and their features of atherosclerotic cardiovascular diseases were observed. Screening for CD36-D in both CAD patients (n =319) and healthy subjects (n =1,239) were underwent. Results: The morbidity of CAD was significantly higher in CD36-D patients than in the general population; 50% of patients (20 out of 40) had CAD identified by BMIPP scintigraphy and 37.5% (3 out of 8) by FACS screening, respectively. Three representative CD36-D cases demonstrated severe CAD and atherosclerosis. The frequency of CD36-D was three times higher in CAD patients than in healthy subjects (0.9% vs 0.3%, p <0.0001). Conclusion: The morbidity of CAD is significantly higher in CD36-D patients suffering from severe atherosclerosis, implying that the status of CD36-D might be atherogenic.
Aim: Atherosclerosis and arteriosclerosis are mainly caused by the dysfunction of arterial components, namely, vascular endothelial cells, smooth muscle cells, and the extracellular matrix. Endothelial dysfunction is well established as a predictive surrogate marker of cardiovascular events; however, little is known regarding the clinical implications of vascular smooth muscle dysfunction for cardiovascular disease and microangiopathy. In the present study, we aimed to clarify the association of arterial dysfunction with micro-/macroangiopathy and conventional cardiovascular risk factors in 181 type 2 diabetic patients (T2DM; age±SD, 64±10 years; duration of diabetes, 12±10 years). Methods: Flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) were assessed to evaluate endothelial dysfunction and vascular smooth muscle dysfunction, respectively, by using a novel ultrasound device, UNEXEF18G (Unex Co. Ltd., Japan). Results: The FMD and NMD were 6.4±3.9% and 13.4±6.6%, respectively. No significant differences in FMD were noted between T2DM with and without micro- or macroangiopathy; however, NMD in T2DM patients with micro- and macroangiopathy was significantly lower than that in T2DM patients without angiopathy. NMD decreased with the progression of chronic kidney disease (CKD) stage (p= 0.005), but not FMD (p= 0.071). On multiple regression analysis, significant independent contributors to FMD were age, smoking, systolic blood pressure, glycosylated hemoglobin, and serum total cholesterol, while those for NMD were age, systolic blood pressure, and waist circumference. Conclusion: The relationship of vascular complications and cardiovascular risk factors with NMD is different from that with FMD in type 2 diabetic patients.
Aim: Statins can induce pharmacologic preconditioning and thereby reduce infarct size. Cellular phosphatidylserine (PS) exposition occurs in the course of ischaemia and reperfusion and has been associated with injury. In this experiment we studied the effect of atorvastatin on PS exposition after a standardised ischaemia and reperfusion challenge. Methods: In a double-blind randomised cross-over trial 30 healthy volunteers were allocated to 3 day treatment with atorvastatin (80 mg/day) and placebo (n= 24), or placebo treatment twice (n= 6). At the end of each treatment period, volunteers underwent 10 minutes of forearm ischaemic exercise. At reperfusion radiolabeled annexin A5 was administered intravenously and Gamma camera imaging of both hands was performed 1 and 4 hours after reperfusion. Results: Annexin A5 targeting was not different between atorvastatin treatment (26.1±9.8% and 24.0±9.5% respectively at 1 and 4 hours after reperfusion) and placebo treatment (25.6±11.0% and 24.5±10.7%) (p= 0.99). Our time control experiment did not reveal a carry-over effect. Conclusions: Our results show that treatment with atorvastatin 80 mg does not reduce forearm PS exposition after ischaemic exercise. This suggests that the role of PS exposure in the prevention of ischemia and reperfusion injury by short term treatment with atorvastatin is limited.
Homocysteine is implicated as an early atherosclerotic promoter, which enhances the smooth muscle cell proliferation and produces free radicals that induce cellular damage. These factors must have a role in the progression of atherosclerosis that subsequently leads to vascular mineralization. Aim: Identify a correlation between the plasma concentration of total homocysteine and the amount of minerals that accumulate in the aorta of patients with atherosclerosis. Methods: We performed a cross-sectional study in 13 patients with three-vessel coronary artery disease, undergoing coronary artery bypass surgery. Aortic and mammary artery specimens were analyzed using a scanning electron microscope with an energy dispersive X-ray spectrometer. The homocysteine was determined using an immunonephelometry method. Results: The amount of minerals in the aorta was greater (300±181.6 particles per 500 µm2) than that in the mammary artery (64±45 particles per 500 µm2)(p < 0.01). The average tHcy was 9.5±2.3 µmol/L. The Spearman's rank correlation coefficient was positive between tHcy, and aortic iron (p < 0.05). Conclusions: Our study demonstrates that the aorta is dramatically affected by mineralization compared to the mammary artery. In addition, a direct correlation was identified between the levels of tHcy and the iron particles in the aortic wall.