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Biomedical subjects

Yuji Matsuzawa

Publications and source records attributed to Yuji Matsuzawa.

At least 55 records · Page 3Linked to original sources

Serum lipid survey and its recent trend in the general Japanese population in 2000.

To determine the recent serum lipid levels and other serum variables in the general Japanese population and trends in their changes over the past 40 years, a nationwide survey of serum lipid levels was conducted in 36 institutes from various districts around Japan in 2000. The total number of subjects was 12,839, aged 4 through 99 years. The mean total cholesterol level was 201 mg/dl; 202 mg/dl in men and 200 mg/dl in women. The mean HDL-cholesterol level was 59 mg/dl; 55 mg/dl in men and 65 mg/dl in women. The mean LDL-cholesterol level was 118 mg/dl; 121 mg/dl in men and 115 mg/dl in women. The mean triglyceride level was 118 mg/dl; 136 mg/dl in men and 92 mg/dl in women. The total cholesterol level slightly increased by 5 mg/dl in 10 years. Although the triglyceride level in women did not change, the triglyceride level in men increased over 10 years, especially in the 30s through 70s age bracket, indicating a possible increase in metabolic syndromes in the future. The present results will become the standard serum lipid level data for the Japanese people, and succeeding 10-year surveys will clarify the trends of lipid levels in this country.

Adolescent↗

Inverse relationship between plasminogen activator inhibitor-I activity and adiponectin in overweight and obese women. Interrelationship with visceral adipose tissue, insulin resistance, HDL-chol and inflammation.

Adipose tissue is an active endocrine organ secreting different adipokines such as plasminogen activator inhibitor-1 (PAI-1) and adiponectin, among many others. In this study, we investigated the association between PAI-1 activity and serum adiponectin levels in a group of 444 overweight and obese women and assessed the interrelationship with visceral adipose tissue (VAT; CT-scan L4-L5), insulin resistance (HOMA-IR), HDL cholesterol (HDL-chol) and inflammation (hs-CRP). PAI-1 was inversely related to adiponectin (r = -0.25, p < 0.001; adjusted for age and BMI). After adjustment for age, VAT, HOMA-IR and hs-CRP, the relationship remained significant (r = -0.15; p = 0.001), but disappeared after additional adjustment for HDL-chol (r = -0.09; p = 0.067). Subjects were divided in two groups according to the median levels of adiponectin or PAI-1 levels. PAI-1 activity (19.1 +/- 11.4 vs. 15.8 +/- 8.6 AU/ml; p = 0.003) and adiponectin levels (9.8 +/- 4.6 vs. 8.4 +/- 4.0 microg/ml; p < 0.001) were significantly higher in the low adiponectin/PAI-1 groups. The difference in PAI-1 remained significant after adjustment for age and BMI (p = 0.001), became borderline significant after adjustment for age and VAT (p = 0.052), and disappeared after adjustment for age and HOMA-IR (p = 0.116) or age and HDL-chol (p = 0.443). The difference in adiponectin levels remained significant after adjustment for age, VAT, HOMA-IR and hs-CRP (p = 0.006), but disappeared after additional adjustment for HDL-chol (p = 0.089). Further analyses suggest a contribution of HOMA-IR and/or HDL-chol in the relationship between PAI-1 and adiponectin. HDL-chol was found to be the only factor independently determining both factors. In conclusion, in overweight and obese women, PAI-1 activity was inversely related to serum adiponectin, independent of visceral adipose tissue.

Adiponectin↗

Visfatin: a protein secreted by visceral fat that mimics the effects of insulin.

Fat tissue produces a variety of secreted proteins (adipocytokines) with important roles in metabolism. We isolated a newly identified adipocytokine, visfatin, that is highly enriched in the visceral fat of both humans and mice and whose expression level in plasma increases during the development of obesity. Visfatin corresponds to a protein identified previously as pre-B cell colony-enhancing factor (PBEF), a 52-kilodalton cytokine expressed in lymphocytes. Visfatin exerted insulin-mimetic effects in cultured cells and lowered plasma glucose levels in mice. Mice heterozygous for a targeted mutation in the visfatin gene had modestly higher levels of plasma glucose relative to wild-type littermates. Surprisingly, visfatin binds to and activates the insulin receptor. Further study of visfatin's physiological role may lead to new insights into glucose homeostasis and/or new therapies for metabolic disorders such as diabetes.

Adipocytes↗

Adaptation to fasting by glycerol transport through aquaporin 7 in adipose tissue.

Adipocytes hydrolyze triglycerides and secrete free fatty acids and glycerol into the circulation. The molecular mechanism involved in glycerol transport from adipocytes has not been elucidated. Here, we investigated glycerol and glucose metabolism in mice lacking aquaporin 7 (Aqp7), a member of the aquaglyceroporins expressed in adipose tissue, and demonstrated that Aqp7 functions as a glycerol gateway molecule in vivo. Aqp7-knockout (KO) mice had lower plasma glycerol levels compared with WT mice but had normal plasma free fatty acid levels. The increase in plasma glycerol level in response to beta(3)-adrenergic agonist was severely impaired in KO mice. Epinephrine-stimulated glycerol secretion was also impaired in Aqp7 knockdown adipocytes. During prolonged fasting, plasma glycerol was elevated and the plasma glucose level was maintained in WT mice. In contrast, KO mice showed a disrupted increase of plasma glycerol and rapid reduction of plasma glucose during prolonged fasting. Our findings indicate that the lack of effective glycerol transport from adipocytes by glycerol gateway molecule causes defective adaptation to prolonged fasting.

Adaptation, Physiological↗

CD9-mediated activation of the p46 Shc isoform leads to apoptosis in cancer cells.

CD9, a member of the tetraspanin family, has been shown to be involved in a range of cellular activities, including migration, proliferation and adhesion, but the molecular mechanisms by which it mediates such events is unclear. Here, we found that anti-CD9 monoclonal antibody ALB6 inhibited cell proliferation, reduced cell viability and induced not only morphological changes specific to apoptosis but also molecular changes, as evidenced by TUNEL and annexin-V staining. For the possible mechanism of ALB6-induced apoptosis, ALB6 activated the c-Jun NH2-terminal kinase/stress-activated protein kinase (JNK/SAPK) and p38 mitogen-activated-protein kinase (MAPK) within 5-15 minutes, as well as caspase-3 within 24-48 hours. It is noteworthy that ALB6 induced tyrosine phosphorylation of the p46 Shc isoform specifically and that the overexpression of its dominant-negative form completely suppressed the ALB6-induced activation of JNK/SAPK, p38 MAPK and caspase-3, resulting in the inhibition of apoptotic cell death. These results suggest that CD9 might regulate apoptosis through the specialized signals in human cancer cell lines.

Adaptor Proteins, Signal Transducing↗

Adiponectin down-regulates acyl-coenzyme A:cholesterol acyltransferase-1 in cultured human monocyte-derived macrophages.

Acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) catalyzes the formation of cholesteryl esters (CE) and plays a significant role in formation of macrophage-derived foam cells in atherosclerotic lesions. Adiponectin was reported to play an anti-atherogenic role by inhibiting class A scavenger receptor (SR-A) expression in human macrophages. To further clarify its additional property, we examined its effect on ACAT-1 expression using human macrophages. Immunoblot analyses revealed a significant reduction of ACAT-1 protein by a low concentration (1 microg/ml) of adiponectin. The ACAT activity was also decreased in parallel by adiponectin. Northern blot analyses revealed that all four ACAT-1 mRNA transcripts (2.8, 3.6, 4.3, and 7.0 kb) were decreased almost equally by adiponectin. Furthermore, acetyl-LDL-induced CE-accumulation in these macrophages was reduced significantly by this adipocytokine. These results demonstrate the inhibitory effect of adiponectin on ACAT-1 expression, suggesting that adiponectin may play an anti-atherogenic role by down-regulating the expression of ACAT-1 as well as SR-A in human macrophages.

Adiponectin↗

Hypoadiponectinemia is an independent risk factor for hypertension.

Adiponectin is one of the key molecules in the metabolic syndrome, and its concentration is decreased in obesity, type-2 diabetes, and coronary artery disease. Genetic investigation has revealed that 2 polymorphisms (I164T and G276T) are related to adiponectin concentration and diabetes. To examine whether adiponectin affects hypertension genetically or biologically, we performed a case-control study. A total of 446 diagnosed cases of hypertension (HT) in men and 312 normotensive (NT) men were enrolled in this study. Plasma adiponectin concentration was measured using an enzyme-linked immunosorbent assay system. Single nucleotide polymorphisms were determined by TaqMan polymerase chain reaction method. After adjustment for confounding factors, adiponectin concentration was significantly lower in HT (HT: 5.2+/-0.2 microg/mL; NT: 6.1+/-0.2 microg/mL; P<0.001). Furthermore, multiple regression analysis indicated that hypoadiponectinemia was an independent risk factor for hypertension (P<0.001). Blood pressure was inversely associated with adiponectin concentration in normotensives regardless of insulin resistance. In subjects carrying the TC genotype of the I164T polymorphism, adiponectin concentration was significantly lower (TC: 2.6+/-0.9 microg/mL; TT: 5.5+/-0.1 microg/mL; P<0.01), and most of them had hypertension. In contrast, the G276T polymorphism was not associated with adiponectin concentration or hypertension. In conclusion, hypoadiponectinemia is a marker for predisposition to hypertension in men.

Adiponectin↗

Adiponectin specifically increased tissue inhibitor of metalloproteinase-1 through interleukin-10 expression in human macrophages.

BACKGROUND: Vascular inflammation and subsequent matrix degradation play an important role in the development of atherosclerosis. We previously reported that adiponectin, an adipose-specific plasma protein, accumulated to the injured artery and attenuated vascular inflammatory response. Clinically, high plasma adiponectin level was associated with low cardiovascular event rate in patients with chronic renal failure. The present study was designed to elucidate the effects of adiponectin on matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) in human monocyte-derived macrophages. METHODS AND RESULTS: Human monocyte-derived macrophages were incubated with the physiological concentrations of human recombinant adiponectin for the time indicated. Adiponectin treatment dose-dependently increased TIMP-1 mRNA levels without affecting MMP-9 mRNA levels. Adiponectin also augmented TIMP-1 secretion into the media, whereas MMP-9 secretion and activity were unchanged. Time course experiments indicated that TIMP-1 mRNA levels started to increase at 24 hours of adiponectin treatment and were significantly elevated at 48 hours. Adiponectin significantly increased interleukin-10 (IL-10) mRNA expression at the transcriptional level within 6 hours and significantly increased IL-10 protein secretion within 24 hours. Cotreatment of adiponectin with anti-IL-10 monoclonal antibody completely abolished adiponectin-induced TIMP-1 mRNA expression. CONCLUSIONS: Adiponectin selectively increased TIMP-1 expression in human monocyte-derived macrophages through IL-10 induction. This study identified, for the first time, the adiponectin/IL-10 interaction against vascular inflammation.

Adiponectin↗

Adiponectin I164T mutation is associated with the metabolic syndrome and coronary artery disease.

OBJECTIVES: This study examined the association of mutations in adiponectin gene with the prevalence of coronary artery disease (CAD). BACKGROUND: Coronary artery disease is a major cause of mortality in the industrial countries. Adiponectin gene locus, chromosome 3q27, is the candidate site for CAD. We have reported that adiponectin has antiatherogenic and antidiabetic properties, and that the plasma levels negatively correlated with body mass index (BMI) are significantly low in patients with CAD or type 2 diabetes. METHODS: The study subjects were 383 consecutive patients with angiographically confirmed CAD and 368 non-CAD subjects adjusted for age and BMI in the Japanese population. Single nucleotide polymorphisms (SNPs) in the adiponectin gene were determined by Taqman polymerase chain reaction (PCR) method or a PCR-based assay for the analysis of restriction fragment length polymorphism. The plasma adiponectin concentration was measured by enzyme-linked immunosorbent assay. RESULTS: Among SNPs, the frequency of I164T mutation was significantly higher in CAD subjects (2.9%) than in the control (0.8%, p < 0.05). The plasma adiponectin levels in subjects carrying the I164T mutation were significantly lower than in those without the mutation, and were independent of BMI. In contrast, SNP94 and SNP276, which are reported to be associated with an increased risk of type 2 diabetes, were associated neither with CAD prevalence nor with plasma adiponectin level. Subjects with I164T mutation exhibited a clinical phenotype of the metabolic syndrome. CONCLUSIONS: The I164T mutation in the adiponectin gene was a common genetic background associated with the metabolic syndrome and CAD in the Japanese population.

Adiponectin↗

Adiponectin-induced antiangiogenesis and antitumor activity involve caspase-mediated endothelial cell apoptosis.

Obesity is a risk factor for the development of many severe human diseases such as cardiovascular disorders, diabetes, and cancer, which are tightly linked to angiogenesis. The adipose tissue produces several growth factors/hormones including leptin, tumor necrosis factor alpha, and adiponectin. It has been found that adiponectin levels are reduced in obesity. Here, we report a unique function of adiponectin as a negative regulator of angiogenesis. In vitro, adiponectin potently inhibits endothelial cell proliferation and migration. In the chick chorioallantoic membrane and the mouse corneal angiogenesis assays, adiponectin remarkably prevents new blood vessel growth. Further, we demonstrate that the antiendothelial mechanisms involve activation of caspase-mediated endothelial cell apoptosis. Adiponectin induces a cascade activation of caspases-8, -9, and -3, which leads to cell death. In a mouse tumor model, adiponectin significantly inhibits primary tumor growth. Impaired tumor growth is associated with decreased neovascularization, leading to significantly increased tumor cell apoptosis. These data demonstrate induction of endothelial apoptosis as an unique mechanism of adiponectin-induced antiangiogenesis. Adiponectin, as a direct endogenous angiogenesis inhibitor, may have therapeutic implications in the treatment of angiogenesis-dependent diseases.

Adiponectin↗

Selective suppression of endothelial cell apoptosis by the high molecular weight form of adiponectin.

Adiponectin is an adipocyte-derived, antiatherogenic protein that is present in serum as three isoforms. Total adiponectin levels are decreased in obese or diabetic humans or animal models. This study was designed to elucidate the relative isoform distribution of adiponectin in human disease states and identify the active form of adiponectin toward vascular endothelial cells. The percentage of high molecular weight form (HMW) per total adiponectin was significantly lower in patients with coronary artery disease than control subjects, whereas the hexamer form was similar and the trimer form was significantly higher. During weight reduction in obese subjects, the HMW form increased and the trimer and hexamer forms decreased. Recombinant adiponectin dose-dependently suppressed apoptosis and caspase-3 activity in human umbilical vein endothelial cells (HUVECs). Transduction with dominant-negative AMP-activated protein kinase (AMPK) abolished the suppressive effect of adiponectin on HUVECs. Gel filtration chromatography was used to separate the adiponectin isoforms, and the antiapoptotic effect toward HUVECs was only observed with the HMW form. These data suggest that HMW adiponectin specifically confers the vascular-protective activities of this adipocytokine. The full text of this article is available online at http://circres.ahajournals.org.

AMP-Activated Protein Kinases↗

Effects of rosiglitazone on gene expression in subcutaneous adipose tissue in highly active antiretroviral therapy-associated lipodystrophy.

Highly active antiretroviral therapy (HAART) has improved the prognosis of human immunodeficiency virus (HIV)-infected patients but is associated with severe adverse events, such as lipodystrophy and insulin resistance. Rosiglitazone did not increase subcutaneous fat in patients with HAART-associated lipodystrophy (HAL) in a randomized, double-blind, placebo-controlled trial, although it attenuated insulin resistance and decreased liver fat content. The aim of this study was to examine effects of rosiglitazone on gene expression in subcutaneous adipose tissue in 30 patients with HAL. The mRNA concentrations in subcutaneous adipose tissue were measured using real-time PCR. Twenty-four-week treatment with rosiglitazone (8 mg/day) compared with placebo significantly increased the expression of adiponectin, peroxisome proliferator-activated receptor-gamma (PPARgamma), and PPARgamma coactivator 1 and decreased IL-6 expression. Expression of other genes involved in lipogenesis, fatty acid metabolism, or glucose transport, such as acyl-CoA synthase, adipocyte lipid-binding protein, CD45, fatty acid transport protein-1 and -4, GLUT1, GLUT4, keratinocyte lipid-binding protein, lipoprotein lipase, PPARdelta, and sterol regulatory element-binding protein-1c, remained unchanged. Rosiglitazone also significantly increased serum adiponectin concentration. The change in serum adiponectin concentration was inversely correlated with the change in fasting serum insulin concentration and liver fat content. In conclusion, rosiglitazone induced significant changes in gene expression in subcutaneous adipose tissue and ameliorated insulin resistance in patients with HAL. Increased expression of adiponectin might have mediated most of the favorable insulin-sensitizing effects of rosiglitazone in these patients.

Adiponectin↗

Complement C1q regulates LPS-induced cytokine production in bone marrow-derived dendritic cells.

We show here that C1q suppresses IL-12p40 production in LPS-stimulated murine bone marrow-derived dendritic cells (BMDC). Serum IL-12p40 concentration of C1q-deficient mice was higher than that of wild-type mice after intraperitoneal LPS-injection. Because neither globular head of C1q (gC1q) nor collagen-like region of C1q (cC1q) failed to suppress LPS-induced IL-12p40 production, both gC1q and cC1q, and/or some specialized conformation of native C1q may be required for the inhibition. While C1q did not affect mRNA expression of Toll-like receptor 4 (TLR4), MD-2, and myeloid differentiation factor 88 (MyD88), BMDC treated with C1q showed the reduced activity of NF-kappaB and the delayed phosphorylation of p38, c-Jun N-terminal kinase, and extracellular signal-regulated kinase after LPS-stimulation. CpG oligodeoxynucleotide-induced IL-12p40 and TNF-alpha production, another MyD88-dependent TLR-mediated signal, was also suppressed by C1q treatment. Therefore, C1q is likely to suppress MyD88-dependent pathway in TLR-mediated signals. In contrast, C1q failed to suppress colony formation of B cells responding to LPS or LPS-induced CD40 and CD86 expression on BMDC in MyD88-deficient mice, indicating that inhibitory effects of C1q on MyD88-independent pathways may be limited. Taken together, C1q may regulate innate and adaptive immune systems via modification of signals mediated by interactions between invading pathogens and TLR.

Adaptor Proteins, Signal Transducing↗

Absence of c-kit gene mutations in gastrointestinal stromal tumours from neurofibromatosis type 1 patients.

Most sporadic gastrointestinal stromal tumours (GISTs) have somatic c-kit gene mutations that are considered to be causal. Neurofibromatosis type 1 (NF1) is caused by mutations of the NF1 gene and NF1 patients have an increased risk of developing GISTs. Since most neoplasms are considered to develop as a result of the combination of several gene mutations, these findings suggest that GISTs from NF1 patients might have somatic c-kit gene mutations and that sporadic GISTs from non-NF1 patients might have somatic NF1 gene mutations. The present study analysed 29 GISTs from seven NF1 patients for c-kit gene mutations and ten sporadic GISTs from ten non-NF1 patients for NF1 mutations. Exons 9, 11, 13, and 17 of the c-kit gene were amplified and directly sequenced after the extraction of genomic DNA from wax-embedded tissues from 26 GISTs from five NF1 patients. The whole coding region of the c-kit cDNA and the whole coding region of the NF1 cDNA were amplified and directly sequenced after RNA extraction and cDNA synthesis in three fresh GIST tissues from two NF1 patients and ten fresh GIST tissues from ten non-NF1 patients. Of the ten sporadic GISTs, eight had heterozygous mutations at exon 11, and one at exon 9, of c-kit. Heterozygous NF1 gene mutations were detected in GISTs from the two NF1 patients from whom fresh tissues were available. None of the 29 GISTs derived from NF1 patients had detectable c-kit gene mutations and none of the ten GISTs derived from non-NF1 patients had detectable NF1 mutations. These results suggest that the pathogenesis of GISTs in NF1 patients is different from that in non-NF1 patients.

Base Sequence↗

Basic fibroblast growth factor promotes the trans-differentiation of mouse bone marrow cells into hepatic lineage cells via multiple liver-enriched transcription factors.

BACKGROUND/AIMS: Evidence that bone marrow cells have trans-differentiating potential to hepatocytes has been described in recent reports. However, the molecular mechanism underlying this phenomenon is unclear. To address this issue, we investigated the parameters involved in the trans-differentiation of bone marrow cells into a hepatic lineage. METHODS: Mouse BM cells were cultured in a collagen gel without or with growth factors including basic fibroblast growth factor. The expression of hepatocyte-specific markers, cholangiocyte-specific marker and liver-enriched transcription factors was identified by RT-PCR and immunohistochemistry. RESULTS: Basic fibroblast growth factor was found to be the most effective for inducing albumin in cultured BM cells. Furthermore, on stimulation of basic fibroblast growth factor, BM cells were found to express other hepatocyte-specific markers and a cholangiocyte-specific marker. This conversion was found to be associated with the induction of transcription factors including hepatocyte nuclear factors and GATA family proteins. CONCLUSIONS: We established an in vitro culture system in which mouse bone marrow cells could trans-differentiate to hepatic lineage cells in response to growth factors, without cell fusion. In particular, basic fibroblast growth factor has the ability to induce the trans-differentiation into hepatic lineage cells from BM cells.

Albumins↗

Primary cardiovascular events and serum lipid levels in elderly Japanese with hypercholesterolemia undergoing 6-year simvastatin treatment: a subanalysis of the Japan lipid intervention trial.

OBJECTIVES: To determine the relationship between serum lipid levels and the incidence of coronary events in older Japanese hypercholesterolemic patients without prior coronary heart disease (CHD). DESIGN: Post hoc subanalysis of the results in the Japan Lipid Intervention Trial. SETTING: A large-scale cohort observational study conducted throughout Japan. PARTICIPANTS: Men aged 35 to 70 and postmenopausal women younger than 70 with serum total cholesterol (TC) level of 220 mg/dL or greater treated for 6 years with low-dose simvastatin (52,421 total patients). After exclusion of 5,127 patients because of prior CHD and 4,934 patients because of incomplete data, 42,360 patients were divided into an older (9,860 patients, aged 65-70, mean age 67.1) and younger (32,500 patients, younger than 65, mean age 54.9) group and analyzed. MEASUREMENTS: Fasting serum lipid levels were measured every 6 months. Major coronary events, including fatal or nonfatal myocardial infarction, and sudden cardiac death as the primary endpoint and other cardiovascular diseases, including onset of angina pectoris, cerebrovascular events, and any causes of death, as the secondary endpoints were monitored. RESULTS: Simvastatin treatment in older patients was as safe and effective as in younger patients. Incident rates of major coronary events were 1.30 per 1,000 patient-years in the older group and 0.80 per 1,000 patient-years in the younger group. The incidence of a major coronary event was correlated to serum TC and low-density lipoprotein cholesterol (LDL-C) levels in both groups. The absolute risk of major coronary events in the older group was higher than in the younger group at any level of LDL-C, whereas the relative risk increased by 1.7% with an elevation of each 1 mg/dL LDL-C level in both groups. In the older group, the risk of major coronary events also increased as triglyceride level increased, whereas the risk decreased as high-density lipoprotein cholesterol level increased above 60 md/dL. CONCLUSION: The LDL-C level-dependent increase of relative risk of CHD was similar in elderly and younger patients, whereas the absolute risk at any LDL-C level in elderly patients was higher than in younger patients.

Adult↗