Toru Miyoshi

Association of serum levels of arachidonic acid and eicosapentaenoic acid with prevalence of major adverse cardiac events after acute myocardial infarction

We studied the association of serum levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA) with the prevalence of major adverse cardiac events (MACE) after acute myocardial infarction (AMI). We measured serum AA and EPA on admission in 146 consecutive AMI patients. The primary clinical endpoint was occurrence of MACE, defined as cardiac death, occurrence of heart failure, reinfarction, recurrent angina pectoris, and requirement of coronary intervention. Common logarithmic transformed serum levels of AA (logAA) and EPA (logEPA) were used in the analyses. The optimum cutoff point of each fatty acid used to distribute patients into two groups for Kaplan–Meier analysis was determined by receiver operating characteristic curves analysis. MACE occurred in 40 patients (27.4%). Kaplan–Meier analysis disclosed that the group with a logAA above the cutoff point [145.3xa0μg/mL (logAA 2.162)] showed a higher prevalence of MACE than those with a logAA below the cutoff point (Pxa0<xa00.01). Conversely, the prevalence of MACE was significantly higher in the group with a logEPA below the cutoff point [52.3xa0μg/mL (logEPA 1.719)] compared to the group with a logEPA above it (Pxa0<xa00.01). Similar to logAA, logAA/logEPA showed significant differences in the MACE-free curve between the two groups (cutoff 1.301, Pxa0<xa00.001). Cox proportional hazards regression analysis suggested that logAA, logEPA, and logAA/logEPA were independently associated with the prevalence of MACE. Although the present study included a limited number of patients with single-time point measurement, the results suggested an association of logAA, logEPA, and logAA/logEPA with the prevalence of MACE after AMI. The present study warrants further studies involving a large number of patients to confirm that the serum levels of these fatty acids and their ratios are predictors of MACE after AMI.

Microarray analysis of gene expression in mouse aorta reveals role of the calcium signaling pathway in control of atherosclerosis susceptibility

Inbred mouse strains C57BL/6J (B6) and C3H/HeJ (C3H) exhibit a marked difference in atherosclerotic lesion formation when deficient in apolipoprotein E (apoE(-/-)), and the arterial wall has been identified as a source of the difference in atherosclerosis susceptibility. In the present study, differences in gene expression in aortic walls of the two strains were analyzed by microarrays. Total RNA was extracted from the aorta of 6-wk-old female B6 and C3H apoE(-/-) mice fed a chow or Western diet. There were 1,514 genes in chow fed mice and 590 genes in Western fed mice that were found to be differentially expressed between the two strains. Pathway analysis of differentially expressed genes suggested a role for the calcium signaling pathway in regulating atherosclerosis susceptibility. Oxidized LDL (oxLDL) induced a dose-dependent rise in cytosolic calcium levels in B6 endothelial cells. oxLDL-induced monocyte chemoattractant protein-1 production was inhibited by pretreatment with calcium chelator EGTA or intracellular calcium trapping compound BAPTA, indicating that calcium ions mediate the effect of oxLDL on monocyte chemoattractant protein-1 induction. The present findings demonstrate involvement of the calcium signaling pathway in the inflammatory process of atherogenesis.

Direct Evidence for a Crucial Role of the Arterial Wall in Control of Atherosclerosis Susceptibility

Background— Inbred mouse strains C57BL/6J (B6) and C3H/HeJ (C3H) exhibit marked differences in atherosclerosis susceptibility. We sought to determine whether the difference in atherosclerosis susceptibility resides at the level of arterial walls. Methods and Results— Thoracic aortic segments from 8-week-old female B6 and C3H apolipoprotein E–deficient mice were transplanted into the infrarenal aorta of 10-week-old female F1 mice. After transplantation, recipients were maintained on a chow diet for 16 weeks. The donor aortic segments of B6 mice developed significantly larger atherosclerotic lesions than those of C3H (44 983±11 702 versus 5600±4885 &mgr;m2 per section; P=0.011). Expression of vascular cell adhesion molecule (VCAM)-1 by endothelial cells was examined both in vitro and in vivo. B6 mice expressed significantly more VCAM-1 than their C3H counterparts. Sequence analysis of VCAM-1 cDNA revealed a nucleotide difference in the coding region that resulted in substitution of an amino acid in the protein product. Conclusions— These data provide direct proof that factors operating in the vessel wall, particularly endothelial cells, can serve as atherosclerosis modifiers and suggest a possibility for the contribution of VCAM-1 to atherosclerosis susceptibility.

Identification of Soat1 as a Quantitative Trait Locus Gene on Mouse Chromosome 1 Contributing to Hyperlipidemia

We previously identified two closely linked quantitative trait loci (QTL) on distal chromosome 1 contributing to major variations in plasma cholesterol and triglyceride levels in an intercross derived from C57BL/6 (B6) and C3H/HeJ (C3H) apolipoprotein E-deficient (apoE−/−) mice. Soat1, encoding sterol o-acyltransferase 1, is a functional candidate gene located underneath the proximal linkage peak. We sequenced the coding region of Soat1 and identified four single nucleotide polymorphisms (SNPs) between B6 and C3H mice. Two of the SNPs resulted in amino-acid substitutions (Ile147Val and His205Tyr). Functional assay revealed an increased enzyme activity of Soat1 in peritoneal macrophages of C3H mice relative to those of B6 mice despite comparable protein expression levels. Allelic variants of Soat1 were associated with variations in plasma cholesterol and triglyceride levels in an intercross between B6.apoE−/− and C3H.apoE−/− mice. Inheritance of the C3H allele resulted in significantly higher plasma lipid levels than inheritance of the B6 allele. Soat1 variants were also significantly linked to major variations in plasma esterified cholesterol levels but not with free cholesterol levels. Trangenic expression of C3H Soat1 in B6.apoE−/− mice resulted in elevations of plasma cholesterol and triglyceride levels. These results indicate that Soat1 is a QTL gene contributing to hyperlipidemia.

Quantitative trait locus analysis of circulating adhesion molecules in hyperlipidemic apolipoprotein E-deficient mice

Circulating soluble adhesion molecules have been suggested as useful markers to predict several clinical conditions such as atherosclerosis, type 2 diabetes, obesity, and hypertension. To determine genetic factors influencing plasma levels of soluble vascular cell adhesion molecule-1 (VCAM-1) and P-selectin, quantitative trait locus (QTL) analysis was performed on an intercross between C57BL/6J (B6) and C3H/HeJ (C3H) mouse strains deficient in apolipoprotein E-deficient (apoE−/−). Female F2 mice were fed a western diet for 12xa0weeks. One significant QTL, named sVcam1 (71xa0cM, LOD 3.9), on chromosome 9 and three suggestive QTLs on chromosomes 5, 13 and 15 were identified to affect soluble VCAM-1 levels. Soluble P-selectin levels were controlled by one significant QTL, named sSelp1 (8.5xa0cM, LOD 3.4), on chromosome 16 and two suggestive QTLs on chromosomes 10 and 13. Both adhesion molecules showed significant or an apparent trend of correlations with body weight, total cholesterol, and LDL/VLDL cholesterol levels in the F2 population. These results indicate that plasma VCAM-1 and P-selectin levels are complex traits regulated by multiple genes, and this regulation is conferred, at least partially, by acting on body weight and lipid metabolism in hyperlipidemic apoE−/− mice.

Effect of cilnidipine on normal to marginally elevated urine albumin-creatinine ratio in asymptomatic non-diabetic hypertensive patients: an exponential decay curve analysis.

AbstractBackground: High-normal urinary albumin excretion has been reported to have clinical significance with respect to progression of proteinuria and hypertension.n Objective: We analysed the effect of cilnidipine (10 mg/day) on morning systolic blood pressure (SBP) and urine albumin-creatinine ratio (UACR) in 16 non-diabetic hypertensive patients with a normal to marginally elevated UACR (mean ± SD 29.4 ± 21.7; range 7.5–72.9 mg/g creatinine).n Methods: Sequential home BP and UACR data were fitted to a simple exponential function as follows: y = α · e−t/β+ γ, where y is SBP (mmHg) or UACR (mg/g creatinine); α is the extent of the SBP (mmHg)- or UACR (mg/g creatinine)-lowering effect; β (days) is the time-constant for SBP or UACR decrease; t is the number of days after the start of cilnidipine administration; and γ is the finally stabilized SBP (mmHg) or UACR (mg/g creatinine).n Results: Mean ± SD morning SBP and UACR decreased by 20.4 ±11.4mmHg and 15.2±13.1 mg/g creatinine, respectively, as determined by coefficient a. The mean ± SD time-constant for UACR decrease was significantly longer than that for BP decrease (43.5 ± 22.9 vs 15.4 ± 7.1 days). UACR reduction correlated with pre-treatment UACR values (correlation coefficient [R] = 0.88, p < 0.01) but not with BP decrease.n Conclusions: The present study demonstrated that cilnidipine reduced UACR in hypertensive patients with normal to marginally elevated UACR independent of its BP-lowering effect.