Establishment of a novel murine model of ischemic cardiomyopathy with multiple diffuse coronary lesions.

Objectives: Atherosclerotic lesions of the coronary arteries are the pathological basis for myocardial infarction and ischemic cardiomyopathy. Progression of heart failure after myocardial infarction is associated with cardiac remodeling, which has been studied by means of coronary ligation in mice. However, this ligation model requires excellent techniques.

Deletion of progranulin exacerbates atherosclerosis in ApoE knockout mice.

Aims: Progranulin (PGRN) is a multifunctional protein known to be involved in inflammation. However, the relation between PGRN and atherosclerosis remains elusive. The aim of this study was to define the role of PGRN in the development of atherosclerosis.

Dietary manipulation and social isolation alter disease progression in a murine model of coronary heart disease.

Background: Mice with a deficiency in the HDL receptor SR-BI and low expression of a modified apolipoprotein E gene (SR-BI KO/ApoeR61(h/h)) called 'HypoE' when fed an atherogenic, 'Paigen' diet develop occlusive, atherosclerotic coronary arterial disease (CHD), myocardial infarctions (MI), and heart dysfunction and die prematurely (50% mortality ~40 days after initiation of this diet). Because few murine models share with HypoE mice these cardinal, human-like, features of CHD, HypoE mice represent a novel, small animal, diet-inducible and genetically tractable model for CHD. To better describe the properties of this model, we have explored the effects of varying the composition and timing of administration of atherogenic diets, as well as social isolation vs.

Thyroid function influences serum apolipoprotein B-48 levels in patients with thyroid disease.

Aim: Apolipoprotein B-48 (apoB-48) is a major apolipoprotein of intestine-derived chylomicrons (CM) and CM remnants (CMR). Clinically overt hypothyroidism (OH) has been associated with premature and accelerated coronary atherosclerosis. To clarify the clinical significance of apoB-48 measurement in patients with thyroid disease, we investigated the correlations between the serum apoB-48 level and thyroid hormones.

Effect of probucol on antioxidant properties of HDL in patients with heterozygous familial hypercholesterolemia.

Aim: High density lipoprotein (HDL) has multi-antiatherogenic effects such as antioxidation and anti-inflammation, in addition to being a key mediator of reverse cholesterol transport. Probucol, known as a lipid lowering drug, is also a potent antioxidant, but it decreases serum HDL cholesterol (HDL-C) levels. To elucidate the effect of probucol on antioxidant properties of HDL, we investigated the function of HDL derived from patients with heterozygous familial hypercholesterolemia (FH) who have been treated with probucol.

Serum adiponectin level is correlated with the size of HDL and LDL particles determined by high performance liquid chromatography.

Objective: Adiponectin (APN) improves insulin resistance and prevents atherosclerosis, and HDL removes cholesterol from atherosclerotic lesions. We have demonstrated that serum HDL-cholesterol (HDL-C) and APN concentrations are positively correlated and that APN accelerates reverse cholesterol transport (RCT) by increasing HDL synthesis in the liver and cholesterol efflux from macrophages. We previously reported that APN reduced apolipoprotein (apo) B secretion from the liver.

Current therapy for patients with sitosterolemia--effect of ezetimibe on plant sterol metabolism.

Sitosterolemia is a rare, autosomal recessive inherited sterol storage disease associated with high tissue and serum plant sterol concentrations, caused by mutations in the adenosine triphosphate-bind-ing cassette (ABC) transporter ABCG5 or ABCG8 genes. Markedly increased serum concentration of plant sterols. such as sitosterol and campesterol, cause premature atherosclerosis and massive xanthomas.

Molecular mechanisms of ezetimibe-induced attenuation of postprandial hypertriglyceridemia.

Aim: Postprandial hypertriglyceridemia (PHTG) has been shown repeatedly to be associated with metabolic syndrome and atherosclerotic cardiovascular diseases. We have recently reported that ezetimibe inhibits PHTG in patients with type IIb hyperlipidemia. Ezetimibe was also reported to atten-uate PHTG in combination with low-dose statins in patients with obesity or metabolic syndrome.

Molecular mechanisms of HDL-cholesterol elevation by statins and its effects on HDL functions.

Numerous large-scale clinical studies have revealed that the low-density lipoprotein cholesterol (LDL-C)-lowering effect of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors (statins) prevents coronary heart disease (CHD). Statins have not only LDL-C-lowering effects but also high-density lipoprotein cholesterol (HDL-C)-elevating effects, which differ among statins. In this article, we discuss the molecular mechanisms of HDL-C elevation by statins and its effect on HDL functions.

Fenofibrate reduces postprandial hypertriglyceridemia in CD36 knockout mice.

Aim: Metabolic syndrome (MetS) and postprandial hypertriglyceridemia (PHTG) are closely related and both are associated with coronary heart disease. We have demonstrated that CD36 deficiency is prevalent in the genetic background of MetS and is accompanied by PHTG concomitantly with an increase in remnants and a decrease in high density lipoprotein cholesterol. These findings make CD36 knockout mice (CD36KO) an interesting model for evaluating PHTG in MetS.

Differential reactivities of four homogeneous assays for LDL-cholesterol in serum to intermediate-density lipoproteins and small dense LDL: comparisons with the Friedewald equation.

Background: In routine clinical laboratory testing and numerous epidemiological studies, LDL-cholesterol (LDL-C) has been estimated commonly using the Friedewald equation. We investigated the relationship between the Friedewald equation and 4 homogeneous assays for LDL-C.

Methods: LDL-C was determined by 4 homogeneous assays [liquid selective detergent method: LDL-C (L), selective solubilization method: LDL-C (S), elimination method: LDL-C (E), and enzyme selective protecting method: LDL-C (P)].

Impaired insulin secretion in four Tangier disease patients with ABCA1 mutations.

Aim: Tangier disease (TD), caused by deficiency of ATP-binding cassette transporter A1, is characterized by the absence of high density lipoprotein and the accumulation of cholesteryl esters in many tissues. Recently, it has been reported that ABCA1 is expressed in pancreatic beta cells and mice with specific inactivation of ABCA1 in beta cells showed markedly impaired insulin secretion, suggesting that ABCA1 deficiency may be involved in diabetes. The aim of the current study was to confirm these findings by the oral glucose tolerance test (OGTT) in human subjects with ABCA1 deficiency.

Adiponectin prevents atherosclerosis by increasing cholesterol efflux from macrophages.

Plasma high density lipoprotein (HDL)-cholesterol levels are inversely correlated to the risk of atherosclerotic cardiovascular diseases. Reverse cholesterol transport (RCT) is one of the major protective systems against atherosclerosis, in which HDL particles play a crucial role to carry cholesterol derived from peripheral tissues to the liver. Recently, ATP-binding cassette transporters (ABCA1, ABCG1) and scavenger receptor (SR-BI) have been identified as important membrane receptors to generate HDL by removing cholesterol from foam cells.

Increased lipid rafts and accelerated lipopolysaccharide-induced tumor necrosis factor-alpha secretion in Abca1-deficient macrophages.

Lipid rafts on the cell surface are believed to be very important as platforms for various cellular functions. The aim of this study was to know whether defective lipid efflux may influence lipid rafts on the cell surface and their related cellular functions. We investigated macrophages with defective lipid efflux from ATP binding cassette transporter A1-deficient (Abca1-KO) mice.

Probucol enhances the expression of human hepatic scavenger receptor class B type I, possibly through a species-specific mechanism.

Objective: Scavenger receptor class B type I (SR-BI) is a major receptor for high-density lipoproteins (HDL) in the liver, which is the terminus of reverse cholesterol transport. Overexpression of SR-BI attenuated experimental atherosclerosis in murine models, concomitant with a reduction in plasma HDL-cholesterol levels. Probucol is known to be a potent hypolipidemic drug to regress xanthoma formation and carotid atherosclerosis in conjunction with a marked reduction in HDL-cholesterol levels.

Human scavenger receptor class B type I is expressed with cell-specific fashion in both initial and terminal site of reverse cholesterol transport.

The reverse cholesterol transport (RCT) is one of the major protective systems against atherosclerosis, in which high-density lipoprotein (HDL) removes cholesterol from lipid-laden cells and delivers it to the liver. Scavenger receptor class B type I (SR-BI) is a HDL receptor in the liver and adrenal glands and is involved in the selective uptake of cholesteryl ester from HDL, which has been extensively, analyzed using rodent models. However, the expression and regulation of the human homologue of this receptor are not known yet.

Pathophysiology of human genetic CD36 deficiency.

CD36, originally identified as glycoprotein IV on platelets, is an 88-kDa integral membrane protein that has multiple ligands and is expressed in the cardiovascular system (ie, blood vessel walls and the heart). Human genetic CD36 deficiency is relatively frequent in Asian and African populations. Investigation into the pathophysiology of this disorder has shown that CD36 may play an important role as a major scavenger receptor for oxidized low-density lipoproteins and as a crucial transporter for long-chain fatty acids.

Dominant expression of ATP-binding cassette transporter-1 on basolateral surface of Caco-2 cells stimulated by LXR/RXR ligands.

ATP-binding cassette transporter-1 (ABCA1) is a cause of Tangier disease, which is a familial deficiency of plasma high density lipoproteins (HDL). This molecule is known to be expressed in the multiple tissues and organs including small intestines, liver, and macrophages in the blood vessels. Recent in vivo studies suggested that ABCA1 plays some roles in the flux of cholesterol in the intestines.