Apolipoprotein A-V (apoA-V) is a recently discovered apolipoprotein that appears to have a role in plasma triglyceride (TG) transport. We have developed an ELISA for apoA-V using monoclonal antibodies that has a lower limit of detection of 0.3 ng/ml and linearity up to 20 ng/ml. The ELISA was then used to quantify plasma apoA-V in 196 healthy subjects and 106 patients with insulin-resistant diabetes mellitus. In the healthy subjects, total apoA-V concentration was 179.2 ؎ 74.8 ng/ml, and it was greater in females than in males ( P Ͻ 0.005). It was correlated positively with the plasma HDL cholesterol ( r ‫؍‬ 0.32, P Ͻ 0.0001), apoA-I ( r ‫؍‬ 0.27, P ‫؍‬ 0.0001), and apoE ( r ‫؍‬ 0.18, P ‫؍‬ 0.011) concentrations and negatively with plasma TG concentration ( r ‫؍‬ ؊ 0.22, P ‫؍‬ 0.021). In relation to single nucleotide polymorphism 3 ( ؊ 1131C/T) of the apoA-V gene, apoA-V concentration was higher in the T/T type than in the C/C type ( P Ͻ 0.01). Plasma TG concentration was lower in the T/T type than in the C/C or C/T type ( P Ͻ 0.05). ApoA-V concentration was lower in the diabetic patients (69.4 ؎ 44.3 ng/ml; P Ͻ 0.01) than in the healthy controls. Plasma triglyceride (TG) levels are influenced by both genetic and environmental factors and are a major independent risk factor for coronary heart disease (1, 2). Plasma TG concentration is influenced by many factors. These include apolipoproteins A-I, A-IV, C-II, and C-III, LPL, LCAT, cholesteryl ester transfer protein, and phospholipid transfer protein (3-11). These factors and their associated gene-environment interactions are of importance in the pathogenesis of coronary heart disease.Apolipoprotein A-V (apoA-V) has recently been identified by comparative sequencing of human and mouse DNA and is located ‫ف‬ 27 kb distal to the apoA-IV gene in the APOA1/C3/A4 gene cluster on chromosome 11q23 (12). ApoA-V, shown to be expressed mostly in liver and independently named regeneration-associated protein 3, is upregulated after the early phase of liver regeneration after hepatectomy in rat (13). In mice overexpressing the human apoA-V gene, TG concentrations decreased by 50-70%, and in apoA-V gene knockout mice, plasma TG concentrations increased ‫ف‬ 4-fold (12-14). These results suggest that apoA-V expression may strongly influence, and be negatively associated with, plasma TG concentrations. ApoA-V both enhances lipoprotein lipase-mediated hydrolysis of plasma TG and inhibits hepatic VLDL-TG production (15). ApoA-V also stimulates the efflux of cholesterol from cells by a mechanism independent on the ABCA1 protein, as do other exchangeable apolipoproteins, such as apoA-I and apoA-IV (16). It was recently described that apoA-V mRNA is regulated by peroxisome proliferator-activated receptor ␣ agonists (17,18) and that the liver X receptor ligand T0901317 decreases apoA-V mRNA through the activation of sterol-regulatory element binding protein 1c (SREBP-1c) (19). These results raise the possibility that some TG-lowering agents, such as fenofibrate, may act by alte...

Plasma cholesteryl ester transfer protein (CETP) facilitates the transfer of cholesteryl ester (CE) from high density lipoprotein (HDL) to apolipoprotein

Apolipoprotein (apo) J, clusterin, is ubiquitously expressed in many tissues, and is a component of high-density lipoproteins (HDLs).There is experimental evidence that it may be anti-atherogenic through its effects on cholesterol transport, smooth muscle cell proliferation and lipid peroxidation. HDLs containing apo J and apo A-carry paraoxonase (PON1), which protects low-density lipoproteins from oxidative modification; however, the extent to which apo J affects coronary heart disease (CHD) is not known. We have developed a sandwich ELISA that enables apo J to be assayed in the range of 13-200 g/mL. Serum apo J was 52.8 0.8 g/mL (mean SEM; range, 36.0-84.3 g/mL; n 92) in healthy Japanese men, and 49.3 0.5 g/mL (34.5-72.8; n 241) in healthy Japanese women. Multiple regression of these data and results from 67 men with CHD showed that apo J concentration was unrelated to age, sex or body mass index, but was positively related to serum PON1 (p 0.001) and apo B (p 0.02) concentrations. In women, it was also positively related to blood glucose (p 0.02). After adjusting for its associations with covariates, serum apo J averaged 5.4 g/mL, lower in CHD men than in controls (p 0.003). Type 2 diabetics had higher apo J concentrations (men, 83.1 3.4 g/mL, n 64; women, 64.0 2.3 g/mL, n 46) than healthy men and women (p 0.001). In these Type 2 diabetics, apo J concentration was unrelated to PON1 concentration, but was positively related to blood glucose (p 0.01). After adjustment for its relation to blood glucose, the mean apo J concentration was similar in diabetics and healthy subjects. These findings suggest that apo J may be anti-atherogenic in humans, and that its concentration is raised by Type 2 diabetes. J Atheroscler Thromb, 2006; 13:314-322.

No abstract

Cholesteryl ester transfer protein (CETP) deficiency is one of the most important and common causes of hyperalphalipoproteinemia (HALP) in the Japanese. CETP deficiency is thought to be a state of impaired reverse cholesterol transport, which may possibly lead to the development of atherosclerotic cardiovascular disease despite high HDL-cholesterol (HDL-C) levels. Thus, it is important to investigate whether HALP is caused by CETP deficiency. In the present study, we identified two novel missense mutations in the CETP gene among 196 subjects with a marked HALP (HDL-C ജ 2.59 mmol/l ‫؍‬ 100 mg/dl). The two missense mutations, L151P (CTC → CCC in exon 5) and R282C (CGC → TGC in exon 9), were found in compound heterozygous subjects with D442G mutation, whose plasma CETP levels were significantly lower when compared with those in D442G heterozygous subjects. In COS-7 cells expressing the wild type and mutant CETP, these two mutant CETP showed a marked reduction in the secretion of CETP protein into media (0% and 39% of wild type for L151P and R282C, respectively). These results suggested that two novel missense mutations cause the decreased secretion of CETP protein into circulation leading to HALP. By using the Invader ® assay for seven mutations, including two novel mutations of the CETP gene, we investigated their frequency among 466 unrelated subjects with HALP (HDL-C ജ 2.07 mmol/l ‫؍‬ 80 mg/dl). Two novel mutations were rare, but L151P mutation was found in unrelated subjects with a marked HALP.Furthermore, we demonstrated that CETP deficiency contributes to 61.7% and 31.4% of marked HALP and moderate HALP in the Japanese, respectively. Reverse cholesterol transport (RCT) is one of the major protective systems against atherosclerosis, in which small HDL or free apolipoprotein (apo)A-I removes cholesterol from the peripheral cells and delivers it to the liver (1, 2). We have investigated the molecular mechanisms of RCT by analyzing the pathophysiology of subjects with abnormal HDL metabolism and clarified the physiological significance of plasma cholesteryl ester transfer protein (CETP) and hepatic triglyceride lipase in human RCT (3,4). In this system, CETP is known to facilitate the transfer of cholesteryl ester (CE) from HDL to apoB-containing lipoproteins, and is one of the major determinants of plasma HDL-cholesterol (HDL-C) levels in humans (5)(6)(7)(8). This is true especially in the hypertriglyceridemic subjects (9). Furthermore, CETP affects not only plasma HDL-C levels but also the amount of small HDL particles, which may be more important for RCT (8,10).Genetic CETP deficiency is the most important and frequent cause of hyperalphalipoproteinemia (HALP) in the Japanese (11-21). Seven mutations have been demonstrated to cause HALP, including two common mutations: a G-to-A substitution at the 5 Ј splicing donor site of the intron 14 (Int14 ϩ 1 G → A) and a missense mutation of exon Abbreviations: BPI, bactericidal permeability increasing protein; CE, cholesteryl ester; CETP, cholesteryl ester tra...

Both mature and furin-cleaved PCSK9s were removed by LDL-A in homozygous and heterozygous FH either by binding to apoB or by other mechanisms. The ELISA method to measure both forms of plasma PCSK9 would be useful for investigating physiological or pathological roles of PCSK9.

Platelet-activating factor acetylhydrolase (PAF-AH) is a phospholipase A 2 associated with lipoproteins that hydrolyzes platelet-activating factor (PAF) and oxidized phospholipids. We have developed an ELISA for PAF-AH that is more sensitive than previous methods, and have quantified HDLassociated and non-HDL-associated PAF-AH in healthy, hyperlipidemic, and diabetic subjects. In healthy subjects, plasma total PAF-AH concentration was positively correlated with PAF-AH activity and with plasma total cholesterol, triacylglycerol, LDL cholesterol and apolipoprotein B (apoB) concentrations (all P Ͻ 0.01). HDL-associated PAF-AH concentration was correlated positively with plasma apoA-I and HDL cholesterol. Subjects with hyperlipidemia (n ‫؍‬ 73) and diabetes mellitus (n ‫؍‬ 87) had higher HDL-associated PAF-AH concentrations than did controls ( P Ͻ 0.01). Non-HDL-associated PAF-AH concentration was lower in diabetic subjects than in controls ( P Ͻ 0.01). Both hyperlipidemic and diabetic subjects had lower ratios of PAF-AH to apoB ( P Ͻ 0.01) and higher ratios of PAF-AH to apoA-I ( P Ͻ 0.01) than did controls.Our results show that the distribution of PAF-AH mass between HDLs and LDLs is determined partly by the concentrations of the lipoproteins and partly by the mass of enzyme per lipoprotein particle, which is disturbed in hyperlipidemia and diabetes mellitus. -Kujiraoka, T., T. Iwasaki, M. Ishihara, M. Ito, M. Nagano, A. Kawaguchi, S. Takahashi, J. Ishi, M. Tsuji, T. Egashira, I. P. Stepanova, N. E. Miller, and H. Hattori. Altered distribution of plasma PAF-AH between HDLs and other lipoproteins in hyperlipidemia and diabetes mellitus.

Large cell neuroendocrine carcinoma (LCNEC) of the urinary bladder is rare. It is a type of neuroendocrine carcinoma morphologically distinct from small cell carcinoma. We report here a case of primary LCNEC of the urinary bladder. We observed a very large invasive tumor, which was not able to be detected three months previously by cystoscopy or computed tomography. The tumor cells morphologically and immunohistochemically resembled that of pulmonary LCNEC. With prompt cystoprostatectomy and chemotherapy, the patient is free of disease 16 months after diagnosis. Although LCNEC is usually very aggressive, it may be controlled by early diagnosis and treatment.