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Hiroshi Mabuchi

Publications and source records attributed to Hiroshi Mabuchi.

At least 19 recordsLinked to original sources
PubMed2006

Serum lipoprotein lipase mass: clinical significance of its measurement.

Lipoprotein lipase (LPL) is a lipolytic enzyme involved in catalyzing hydrolysis of triglycerides (TG) in chylomicrons and very low-density lipoprotein (VLDL) particles. Over the last decade, increasing attention has been paid to the clinical significance of measuring serum LPL protein mass without heparin injection to the study subjects. In earlier studies, this marker was utilized to classify LPL deficient subjects, which is an extremely rare metabolic disorder with a frequency of one in one million. Later, researchers paid more attention to the clinical significance of measuring this parameter in more common metabolic disorders. Studies have shown that pre-heparin plasma or serum LPL mass has significant relationships with serum lipids and lipoproteins, visceral fat area, insulin resistance, and even the development of coronary atherosclerosis in cross-sectional studies, although this might be a metabolic surrogate marker with almost no catalytic activities, which does not appear to be involved in catalyzing hydrolysis of TG in TG-rich lipoproteins. Recently, a prospective study has demonstrated that low serum LPL concentration predicts future coronary events. Taken together, we suggest that pre-heparin LPL mass in plasma or sera provide us with useful and important information on the development of metabolic disorders leading to atherosclerotic disease.

Diabetes Mellitus, Type 2↗
PubMed2006

Risk of coronary events in Japanese patients with both hypercholesterolemia and type 2 diabetes mellitus on low-dose simvastatin therapy: implication from Japan Lipid Intervention Trial (J-LIT).

Hypercholesterolemic patients with type 2 diabetes mellitus are at increased risk of coronary heart disease (CHD); however, direct evidence is very limited in Japanese patients. The J-LIT is the first nationwide study conducted to assess the relationship between serum lipid levels and development of coronary events in Japanese hypercholesterolemic patients. We analyzed the coronary events in the J-LIT study subjects by having type 2 diabetes or not. Of the total 41,801 subjects without prior CHD who received open-label simvastatin, 5mg/day, 6554 (male 40.2%, age 57.8+/-7.8) subjects had type 2 diabetes, while 35,247 (male 30.0%, age 57.8+/-7.9) did not. In this analysis, relative coronary event risks based on a 0.26 mmol/l (10mg/dl) increase in low density lipoprotein-cholesterol (LDL-C), were similar between hypercholesterolemic subjects with and without type 2 diabetes (17.3% versus 19.4%). Although all subjects were treated with simvastatin, the subjects with type 2 diabetes have significantly more coronary events compared to the subjects without type 2 diabetes (1.80/1000 and 0.76/1000 patient-years, respectively). Given the results above, to reduce the risk of coronary events in Japanese patients with both hypercholesterolemia and type 2 diabetes, careful and strict cholesterol management is needed in addition to the control of blood glucose.

Adult↗
PubMed2006

Raloxifene promotes adipocyte differentiation of 3T3-L1 cells.

To explore the possibility that raloxifene might influence an adipocyte differentiation and lipogenesis, we studied the effects of raloxifene on the expression of adiponectin and other peroxisome proliferator-activated receptor gamma targeting genes using the 3T3-L1 adipocytes. With standard adipogenic inducers, we added raloxifene at various doses for the adipocyte differentiation. Higher doses of raloxifene facilitated lipid accumulation of the 3T3-L1 cells. We next examined the differentiating and differentiated adipocytes and found that raloxifene augmented mRNA levels of adiponectin, adipocyte-specific fatty acid binding protein, and lipoprotein lipase dose-dependently in both. These effects were opposite those of 17beta-estradiol treatment. These findings suggest that raloxifene promotes adipocyte differentiation, providing a novel insight into the treatment of postmenopausal metabolic syndrome with hypoadiponectinemia.

3T3-L1 Cells↗
PubMed2006

A novel mutation in the cardiac myosin-binding protein C gene is responsible for hypertrophic cardiomyopathy with severe ventricular hypertrophy and sudden death.

It has been demonstrated previously that clinical phenotypes of HCM (hypertrophic cardiomyopathy) caused by mutations in the cardiac MyBP-C (myosin-binding protein C) gene show late onset, low penetrance and favourable clinical course. However, we have encountered severe phenotypes in several carriers of the MyBP-C gene mutations. The aim of the present study was to screen novel MyBP-C gene mutations in patients with HCM and to investigate the genetic differences in affected subjects with severe phenotypes. The MyBP-C gene was screened in 292 Japanese probands with HCM, and a novel c.2067+1G-->A mutation was present in 15 subjects in five families. Clinical phenotypes of carriers of the c.2067+1G-->A mutation were compared with those of a previously identified Arg820Gln (Arg820-->Gln) mutation in the MyBP-C gene. The disease penetrance in subjects aged > or =30 years was 90% in carriers of the c.2067+1G-->A mutation and 61% in carriers of the Arg820Gln mutation. Sudden death occurred in four subjects from three families with the c.2067+1G-->A mutation and in two subjects from one family with the Arg820Gln mutation. Two carriers of the c.2067+1G-->A mutation had substantial hypertrophy (maximal wall thickness > or =30 mm). In contrast, two carriers of the Arg820Gln mutation had end-stage HCM. In conclusion, the c.2067+1G-->A mutation is associated with HCM with substantial hypertrophy and moderate incidence of sudden death, whereas the Arg820Gln mutation is associated with end-stage HCM. These observations may provide important prognostic information regarding the clinical practice of HCM.

Adolescent↗
PubMed2006

CETP (cholesteryl ester transfer protein) promoter -1337 C>T polymorphism protects against coronary atherosclerosis in Japanese patients with heterozygous familial hypercholesterolaemia.

CETP (cholesteryl ester transfer protein) and HL (hepatic lipase) play a role in the metabolism of plasma lipoproteins, but the effects of CETP and LIPC (gene encoding HL) genotypes on coronary atherosclerosis may be dependent on LDL (low-density lipoprotein)-receptor activity. Recently, the -1337 C>T polymorphism in the CETP gene has been reported in REGRESS (Regression Growth Evaluation Statin Study) to be a major determinant of promoter activity and plasma CETP concentration. In the present study, we have investigated the effects of the CETP promoter -1337 C>T and LIPC promoter -514 C>T polymorphisms on serum lipid profiles and risk of coronary atherosclerosis in 206 patients (154 males) with heterozygous FH (familial hypercholesterolaemia). To evaluate coronary atherosclerosis, we used CSI (coronary stenosis index) calculated from coronary angiograms. The CETP -1337 T allele was less frequent in subjects with a CSI > or =14 (mean value) in the group with coronary artery disease (P=0.04, as determined by chi(2) test). ANOVA revealed that HDL-C (high-density lipoprotein-cholesterol) and triacylglycerol (triglyceride) levels were not significantly higher in the presence of the CETP promoter -1337 T allele. Combined with LIPC promoter polymorphisms, HDL-C levels were highest and CSI were lowest with CETP -1337 CT+TT and LIPC -514 CC genotypes, but a significant interaction was not shown. A multiple logistic regression analysis revealed that, in patients with coronary atherosclerosis, the CETP- 1337 CC genotype was a significant genetic risk factor in FH (odds ratio=2.022; P=0.0256). These results indicate that the CETP promoter -1337C>T polymorphism is associated with the progression of coronary atherosclerosis in Japanese patients with FH, independent of HDL-C and triacylglycerol levels.

Adult↗
PubMed2006

Low-density lipoprotein apheresis therapy with a direct hemoperfusion column: a Japanese multicenter clinical trial.

Low-density lipoprotein (LDL) apheresis has been applied to patients with familial hypercholesterolemia (FH) with coronary artery disease (CAD). To examine the efficacy and safety of a new type of LDL adsorption column (KLD01, Kaneka, Osaka, Japan), which deals with whole blood without separating plasma, the new system was evaluated in a multicenter trial. The present study included 33 FH patients with CAD (24 males, 9 females, 57 +/- 13 years) who were treated five times with a mean interval of 2.12 +/- 0.60 weeks between treatments. We studied the removal efficacies for serum LDL cholesterol, Lipoprotein(a) (Lp(a)) and triglyceride, the times for the preparation of the system and for treatment, symptoms, and the biochemical data. The scheduled treatments were completed by 31 patients. Serum levels of LDL cholesterol, Lp(a) and triglycerides were all significantly reduced with KLD01; 61.5 +/- 6.2%, 72.4 +/- 5.9% and 69.5 +/- 9.7%, respectively. The times for both setting up the column system (26 +/- 7 min) and treatment (138 +/- 20 min) were shorter with KLD01 than conventional methods. Adverse reactions occurred in eight cases (17 episodes), but the patients fully recovered immediately after each apheresis therapy session. We conclude that the new type of LDL adsorption column, one that deals with whole blood, is a promising apheresis therapy for FH patients in view of its efficacy, reduced time for treatment, and safety.

Adult↗
PubMed2006

Gender difference in coronary events in relation to risk factors in Japanese hypercholesterolemic patients treated with low-dose simvastatin.

BACKGROUND: Gender differences between the risk factors for coronary heart disease and coronary events were examined in the Japan Lipid Intervention Trial, a 6-year observational study. METHODS AND RESULTS: Men (12,575) and women (27,013) were analyzed for risk of coronary events (acute myocardial infarction and sudden cardiac death). Simvastatin reduced serum low-density lipoprotein cholesterol (LDL-C) by 27% in both genders, and increased serum high-density lipoprotein cholesterol (HDL-C) in men (5%) and women (4%). The incidence of coronary events was lower in women (0.64/1,000 patient-years) than in men (1.57/1,000 patient-years). The risk of coronary events increased by 18% in men and 21% in women with each 10 mg/dl elevation of LDL-C, and decreased by 39% in men and 33% in women with each 10 mg/dl elevation of HDL-C. The risk increased proportionally with aging in women, but not in men. Diabetes mellitus (DM) was more strongly related to the risk of coronary events for women (relative risk 3.07) than for men (relative risk 1.58). CONCLUSIONS: The incidence of coronary events is lower in women. Serum LDL-C is related to an increased risk of coronary events to the same extent in both genders. DM seems to be a more important risk factor in women, trading off the lower risk of coronary events among them.

Adult↗
PubMed2006

Pathophysiological roles of the adrenal renin-angiotensin system in patients with primary aldosteronism.

The mechanism of overproduction of aldosterone in primary aldosteronism is unclear. The intraadrenal renin-angiotensin system (RAS) has been suggested to possess the functional role of the synthesizing aldosterone and regulating blood pressure. In order to clarify the pathophysiological roles of adrenal RAS in aldosterone-producing adenoma (APA), we studied the expressions of the messenger RNAs (mRNAs) of renin, angiotensinogen, type 1 (AT1R) and type 2 angiotensin II receptor (AT2R), CYP11B1 (11 beta-hydroxylase gene) and CYP11B2 (aldosterone synthase gene) in 8 patients with angiotensin II-responsive (ATII-R) APA and compared them with the expressions of the same mRNAs in 8 patients with angiotensin II-unresponsive (ATII-U) APA. Quantification of the mRNA of each gene was done using a real-time polymerase chain reaction with specific primers. There were no significant differences between ATII-R APA and ATII-U APA in the mRNA levels of renin, angiotensinogen, AT1 R, CYP11B1 and CYP11B2. The amount of AT2R mRNA was significantly higher in the patients with ATII-R APA than in those with ATII-U APA (p<0.05). These results may suggest that AT2R partially contributes to the overproduction of aldosterone in ATII-R APA.

Adrenal Glands↗
PubMed2006

Effects of fenofibrate therapy on plasma ubiquinol-10 and ubiquinone-10 levels in Japanese patients with hyperlipidemia and type 2 diabetes mellitus.

STUDY OBJECTIVE: To assess the effects of fenofibrate therapy on concentrations of plasma ubiquinol-10 and ubiquinone-10-the reduced and oxidized forms, respectively, of coenzyme Q(10). DESIGN: Prospective, open-label, non-controlled study. SETTING: University clinic and laboratory. PATIENTS: Eighteen patients with hyperlipidemia and type 2 diabetes mellitus. INTERVENTION: Patients received fenofibrate 150 mg/day for 12 weeks. MEASUREMENTS AND MAIN RESULTS: Metabolic parameters were assessed 4, 8, and 12 weeks after the start of fenofibrate treatment. Plasma ubiquinol-10 and ubiquinone-10 levels were measured by reverse-phase high-performance liquid chromatography. At 4, 8, and 12 weeks, significant reductions in fasting triglyceride levels and significant increases in high-density lipoprotein cholesterol levels were noted. Total cholesterol, low-density lipoprotein cholesterol, fasting plasma glucose, and adiponectin levels, however, did not change significantly. Plasma ubiquinol-10 concentrations significantly increased after 8 and 12 weeks (p<0.05 for both), whereas ubiquinone-10 concentrations tended to decrease, especially at 12 weeks. CONCLUSION: Our findings suggest that fenofibrate may help produce energy or prevent oxidation by increasing plasma ubiquinol-10 concentration; this effect may protect against the development and progression of atherosclerosis. In addition, treatment with fenofibrate demonstrated a favorable effect on serum lipid parameters.

Coenzymes↗
PubMed2006

Tissue gene expression of renin-angiotensin system in human type 2 diabetic nephropathy.

OBJECTIVE: Recent studies have proved that blockade of the renin-angiotensin system (RAS) retards the progression of diabetic nephropathy, whereas hyporeninemia is known as a typical state in diabetic subjects. The purpose of this study is to determine whether expression levels of RAS differ between nondiabetic and diabetic renal tissues with accurate quantitative method. RESEARCH DESIGN AND METHODS: Subjects were 66 nondiabetic and 8 diabetic patients with biopsy-proven renal diseases. The eight diabetic subjects suffered from type 2 diabetes with overt proteinuria. Renal histology revealed typical diffuse or nodular lesions with linear IgG deposit on immunofluorescent staining and thickened basement membrane on electronic microscopy. Total RNA from a small part of the renal cortical biopsy specimens was reverse-transcribed, and the resultant cDNA was amplified for new major components of RAS (i.e., renin, renin receptor, angiotensinogen, ACE, ACE2, angiotensin II type 1 receptor, and angiotensin II type 2 receptor) and measured. RESULTS: Among these components, a significant upregulation was observed in the ACE gene in diabetic renal tissue. CONCLUSIONS: The results suggest that renal tissue RAS might be activated in the respect that ACE gene expression is upregulated in spite of a tendency to low renin expression in type 2 diabetic nephropathy.

Adult↗
PubMed2006

Effect of walking with a pedometer on serum lipid and adiponectin levels in Japanese middle-aged men.

OBJECTIVE: To clarify the effects of walking with a pedometer on metabolic parameters, including adiponectin (APN). METHODS: We recruited 44 male Japanese volunteers (age, 37 +/- 9 yrs; body mass index (BMI), 24.2 +/- 2.9 kg/m2; fasting plasma glucose (FPG), 96 +/- 11 mg/dL; total cholesterol (TC) 190 +/- 26 mg/dL; triglycerides (TG) 119 +/- 80 mg/dL; HDL-C56 +/- 14 mg/dL). Subjects were instructed to walk with a pedometer and record the number of steps they walked every day for 50 days. Serum adiponectin (APN) levels were measured by enzyme immunoassay. Treatment effects were examined by Wilcoxon's rank test. RESULTS: The average number of steps was 8211 +/- 2084 per day. There were significant reductions in BMI, sBP, TG and TNF-alpha levels after 50 days, but no changes in adiponectin levels. We then divided the subjects into 2 groups according to the steps walked per day, namely, more than 8000 steps (MT group, n = 22) and less than 8000 steps (LT group, n = 22) and found that the reduction in TG and BP was observed only in the MT group. CONCLUSIONS: Walking with a pedometer is effective for improving metabolic parameters, such as TG and blood pressure, but is not sufficient to increase adiponectin levels in Japanese men.

Adiponectin↗
PubMed2006

Prevalence of metabolic syndrome in the general Japanese population in 2000.

To determine the prevalence of metabolic syndrome in the Japanese general population, we analyzed data from a nationwide survey conducted in 2000. According to the Japanese new diagnostic criteria for metabolic syndrome in 2005, we analyzed 3,264 people aged from 20 to 79 (men, 1,917; women, 1,347) from the total participants. The incidence of metabolic syndrome was 7.8%. Men had a higher incidence (12.1%) than women (1.7%). Most of the women satisfying the criteria were 50 years old or over, while the incidence in men started to rise from their 30s. When we applied the criteria of Adult Treatment Panel III, the incidence was about 3-fold higher. In this population visceral obesity was associated with metabolic abnormalities, such as higher LDL-cholesterol, triglyceride, glucose, and blood pressure and lower HDL-cholesterol. Thus we determined the incidence of metabolic syndrome and each metabolic abnormality in the Japanese general population in 2000 and found an association of visceral obesity with metabolic abnormalities. Intervention to reduce the incidence of metabolic syndrome in Japan is necessary to reduce the risk of cardiovascular disease.

Adult↗
PubMed2006

The relationship of percent body fat by bioelectrical impedance analysis with blood pressure, and glucose and lipid parameters.

The objective of this study was to clarify the clinical significance and usefulness of measuring percent body fat (PBF) when compared with body mass index (BMI) in the Japanese population. A total of 2,483 Japanese individuals (1,380 men and 1,103 women) who underwent a medical checkup from 1999-2002 were employed. PBF was determined using bioelectrical impedance analysis (BIA). Relationships of age, BMI and PBF with several metabolic parameters, including blood pressure, lipids and plasma glucose levels were assessed in both genders separately. In men, PBF was a stronger determinant of total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and triglycerides (TG) compared with age and BMI, whereas in women, age was the strongest determinant of TC and LDL-C. In both genders, BMI was the strongest determinant of serum HDL-C among age, PBF and BMI. Based on these data, we suggest that measuring PBF by BIA is superior to BMI for predicting TC, LDL-C and TG in Japanese men.

Adipose Tissue↗
PubMed2006

Cholesterol-years score is associated with development of senile degenerative aortic stenosis in heterozygous familial hypercholesterolemia.

We retrospectively evaluated the frequency and identified the factors associated with the development of aortic stenosis (AS) in 96 patients with heterozygous familial hypercholesterolemia (FH). The frequency of AS was 31% (4/13) and that of critical stenosis was 15% (2/13) in older patients over the age of 70 years. All 4 patients with AS were female aged more than 70 years who were diagnosed with FH when aged more than 60 years. There were no significant differences in conventional coronary risk factors; however, the age at cardiac catheterization, age at diagnosis of FH and the cholesterol-years score (CYS) with AS were significantly higher than those without AS (p=0.006, p=0.017, p=0.021, respectively). In multiple regression analysis, CYS was a significant independent predictor for the development of AS (p=0.037) in 13 older patients over the age of 70 years. These results suggest that physicians should be aware that AS needs attention in older patients with heterozygous FH, especially women who have been diagnosed late in life and those who have been inadequately treated.

Adult↗
PubMed2006

Analysis of ankyrin-B gene mutations in patients with long QT syndrome.

OBJECTIVE: To identify the ankyrin-B gene mutations that cause long QT syndrome (LQTS) and determine the prevalence of such mutations in Japanese patients with LQTS. METHODS: We conducted a search for ankyrin-B gene mutation in 78 unrelated patients with LQTS (28 males and 50 females, aged 2 to 89 years). With informed consent from all the subjects and/or their parents, genomic DNA was purified from the white blood cells of the patients and amplified using polymerase chain reaction (PCR). Single-strand conformational polymorphism (SSCP) analysis of the amplified DNA was performed to screen for mutations and aberrant SSCP products were isolated and sequenced by dye terminator cycle sequencing method using an automated fluorescent sequencer. PCR and restriction fragment length polymorphism (PCR-RFLP) analysis was carried out to further confirm the missense mutations by comparison with samples from 150 normal healthy individuals. RESULTS: We identified a T to A transition mutation at position 4,603 in exon 40, resulting in the substitution of arginine for a tryptophan at amino acid residue 1,535 (W1535R) in the regulatory domain of 220-kD ankyrin-B, which is a highly conserved domain shared by different species. CONCLUSION: This novel missense mutation in the ankyrin-B gene may be a cause of type 4 LQTS. Ankyrin-B gene mutation might not play the major role in LQTS in Japanese.

Adolescent↗
PubMed2005

Changes in cardiac tissue characterization in carriers with gene mutations associated with hypertrophic cardiomyopathy.

BACKGROUND: Early detection in patients with hypertrophic cardiomyopathy (HCM) is very important. Integrated backscatter (IB) provides a useful noninvasive measure of the acoustic properties of the myocardium, and may detect early myocardial changes. METHODS: Thirty-four carriers who had gene mutations causing HCM were studied. The patients were divided into three groups as follows: (1) 21 patients with wall hypertrophy (Group A), (2) 7 patients with ECG abnormalities but without wall hypertrophy (Group B), and (3) 6 carriers with neither ECG abnormalities nor wall hypertrophy (Group C). All subjects underwent ECG, conventional echocardiography and acoustic densitometry. In addition, we studied subjects < or =20 years old from Groups B and C (Group B-2 and Group C-2, respectively), and compared them with control subjects with no cardiac disorders who were < or =20 years old. RESULTS: In Group A, cyclic variations of integrated backscatter (CV-IB) in the interventricular septum and left ventricular posterior wall were significantly smaller than in Group C. The amplitude of IB in the interventricular septum and left ventricular posterior wall in Group A was significantly higher than those in Group C. Even in Group B, CV-IB in the interventricular septum was significantly smaller than those in Group C. Among patients < or =20 years old, CV-IB in the interventricular septum was significantly smaller in Group B-2 than in control subjects, while that in Group C-2 did not differ from that in control subjects. CONCLUSIONS: Changes in tissue characterization were found in the hearts of HCM gene carriers even in the absence of wall hypertrophy. These results suggest that tissue changes detectable by the acoustic densitometry methods may occur in the hearts of HCM gene carriers without wall hypertrophy, and that they may be detectable at the time of appearance of ECG abnormalities.

Adolescent↗