An automated method for measuring lipoprotein lipase and hepatic triglyceride lipase activities in post-heparin plasma.

BACKGROUND: Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) play a central role in triglyceride-rich lipoprotein metabolism by catalyzing the hydrolysis of triglycerides. Quantification of LPL and HTGL activity is useful for diagnosing lipid disorders, but there has been no automated method for measuring these lipase activities. METHODS: The automated kinetic colorimetric method was used for assaying LPL and HTGL activity in the post-heparin plasma using the natural long-chain fatty acid 2-diglyceride as a substrate. LPL activity was determined with apoCII and HTGL activity was determined without apoCII with 2 channel of auto-analyzer. RESULTS: The calibration curve for dilution tests of the LPL and HTGL activity assay ranged from 0.0 to 500 U/L. Within-run CV was obtained within a range of 5%. No interference was observed in the testing of specimens containing potentially interfering substances. The measurement range of LPL activity in the post-heparin plasma was 30-153 U/L, while HTGL activity was 135-431 U/L in normal controls. CONCLUSIONS: The L PL and HTGL activity assays are applicable to quantitating the LPL and HTGL activity in the post-heparin plasma. This assay is more convenient and faster than radiochemical assay and highly suitable for the detection of lipid disorders.

The role of plasma lipoprotein lipase, hepatic lipase and GPIHBP1 in the metabolism of remnant lipoproteins and small dense LDL in patients with coronary artery disease.

BACKGROUND: The relationship between plasma lipoprotein lipase (LPL), hepatic triglyceride lipase (HTGL), glycosylphosphatidylinositol anchored HDL binding protein1 (GPIHBP1) concentration and the metabolism of remnant lipoproteins (RLP) and small dense LDL (sdLDL) in patients with coronary artery disease (CAD) is not fully elucidated. METHODS: One hundred patients who underwent coronary angiography were enrolled. The plasma LPL, HTGL and GPIHBP1 concentrations were determined by ELISA. The time dependent changes in those lipases, lipids and lipoproteins were studied at a time-point just before, and 15min, 4h and 24h after heparin administration. RESULTS: The LPL concentration exhibited a significant positive correlation with HDL-C, and inversely correlated with TG and RLP-C. The HTGL concentration was positively correlated with RLP-C and sdLDL-C. The HTGL ratio of the pre-heparin/post-heparin plasma concentration and sdLDL-C/LDL-C ratio were significantly greater in CAD patients than in non-CAD patients. GPIHBP1 was positively correlated with LPL and inversely correlated with RLP-C and sdLDL-C. CONCLUSION: The HTGL concentration was positively correlated with RLP-C and sdLDL-C, while LPL and GPIHBP1 were inversely correlated with RLP-C and sdLDL-C. These results suggest that elevated HTGL is associated with increased CAD risk, while elevated LPL is associated with a reduction of CAD risk.

A new enzyme-linked immunosorbent assay system for human serum hepatic triglyceride lipase.

There is no established method for measuring human hepatic triglyceride (TG) lipase (HTGL) concentration in serum. In this study, we developed new monoclonal Abs (MoAbs) (9A1 mouse MoAb and 141A1 rat MoAb) that react with HTGL both in serum and in postheparin plasma (PHP) and established a novel ELISA system for measuring serum HTGL and PHP-HTGL concentrations. To confirm the specificity of MoAbs, we performed immunoprecipitation-immunoblotting analysis. Both 9A1 mouse MoAb and 141A1 rat MoAb were able to immunoprecipitate not only recombinant HTGL and PHP-HTGL but also serum HTGL, demonstrating that HTGL exists in serum obtained without heparin injection. This method yielded intra- and interassay coefficients of variation of <6% and showed no cross-reactivity with LPL or endothelial lipase. In clinical analysis on 42 male subjects with coronary artery disease, there were strong positive correlations of serum HTGL concentration to PHP-HTGL concentration (r = 0.727, P < 0.01). Serum HTGL concentrations showed positive correlations to serum TGs (r = 0.314, P < 0.05) and alanine aminotransferase (r = 0.406, P < 0.01), and tendencies toward positive correlations to LDL cholesterol, small dense LDL, and γGTP. These results suggest that this new ELISA method for measuring serum HTGL is applicable in daily clinical practice.

Prognostic Significance of Aberrant Methylation of Solute Carrier Gene Family 5A8 in Lung Adenocarcinoma.

BACKGROUND: Solute carrier family 5 member A8 (SLC5A8) is a sodium-coupled transporter for several chemicals. The SLC5A8 gene has been reported to function as a tumor suppressor gene that contributes to carcinogenesis and tumor progression. The expression of SLC5A8 is silenced in colon neoplasia by hypermethylation of CpG-rich islands located in exon 1. In this study, we assessed the significance of aberrant methylation of the SLC5A8 gene as a prognostic factor for lung adenocarcinoma (AD). METHODS: We analyzed the methylation levels of a consecutive series of 143 node-negative stage I and II lung AD samples using pyrosequencing. RESULTS: The methylation level of exon 1 in the SLC5A8 gene was significantly associated with poor prognosis in cases of node-negative stage I and II lung AD. CONCLUSIONS: Gene silencing of SLC5A8 by hypermethylation was associated with poor prognosis in cases of node-negative stage I and II lung AD.

Rosuvastatin selectively stimulates apolipoprotein A-I but not apolipoprotein A-II synthesis in Hep G2 cells.

Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) are extensively used to regulate dyslipidemia and to reduce atherosclerotic cardiovascular disease. In addition to effectively lowering cholesterol and low-density lipoprotein levels, rosuvastatin and certain other statins can also increase plasma high-density lipoprotein (HDL) cholesterol modestly. However, the mechanism of action of rosuvastatin on HDL metabolic processes is not understood. Using cultured human hepatoblastoma cells (Hep G2) as an in vitro model system, we assessed the effect of rosuvastatin on apolipoprotein (apo) A-I and apo A-II (the major proteins of HDL) synthesis and HDL catabolic processes. Rosuvastatin dose-dependently increased messenger RNA expression and de novo synthesis of apo A-I but not apo A-II. Rosuvastatin selectively increased the synthesis of HDL particles containing only apo A-I (LP A-I) but not particles containing both apo A-I and A-II (LP A-I + A-II). The HDL(3)-protein or HDL(3)-cholesterol ester uptake by Hep G2 cells was not affected by rosuvastatin. The apo A-I-containing particles secreted by rosuvastatin-treated Hep G2 significantly increased cholesterol efflux from fibroblasts. The data indicate that rosuvastatin increases hepatic apo A-I but not apo A-II messenger RNA transcription, thereby selectively increasing the synthesis of functionally active apo A-I-containing HDL particles, which mediate cholesterol efflux from peripheral tissues. We suggest that this mechanism of action of rosuvastatin to increase apo A-I production without apo A-I/HDL removal may result in increased apo A-I turnover that results in accelerated reverse cholesterol transport.

Human chymase expression in a mice induces mild hypertension with left ventricular hypertrophy.

A number of in vitro studies have suggested potential pathophysiological roles of human (h-) chymase. However, the lack of an appropriate animal model has left the in vivo roles of chymase unclear. To approach this problem, a transgenic mouse (TGM) model carrying the h-chymase gene was established. The h-chymase cDNA transgene was constructed with the chicken beta actin promoter and cytomegalovirus immediate early gene enhancer, and injected into mouse oocytes. Homozygous mice with a high copy number of the h-chymase gene suffered from intrauterine death. In three heterozygous TGM lines, h-chymase transgene expression was detected in entire organs, including the heart, vessels, skin, liver, lung, and brain. The h-chymase immunoreactivity was localized in the extracellular matrices of each organ, especially on the basement membranes of vessels. Aortic and hepatic chymase-dependent angiotensin II formations were significantly higher than those in the wild-type littermates. Three independent TGM lines showed the same phenotypic changes: elevation of blood pressure, left ventricular hypertrophy, emaciation with reduction in the lipid tissue, leukocytosis, and oligotrichia. The angiotensin II subtype 1 (AT1) receptor antagonist valsartan suppressed the elevated blood pressure completely and left ventricular hypertrophy incompletely, but did not affect the other phenotypes. These data suggested that in vivo expression of h-chymase caused mild hypertension (AT1 receptor-dependent) with left ventricular hypertrophy (partially AT1 receptor-dependent), and also chronic inflammatory changes (AT1 receptor-independent).

[Cat scratch disease with posterior segment involvement].

PURPOSE: To describe the clinical characteristics of patients with cat scratch disease during the last 2 years. METHODS: Clinical characteristics and anterior and posterior segment manifestations were reviewed in five patients who were serologically diagnosed as having cat scratch disease. RESULTS: Four women and one man were examined. Their ages ranged from 7 to 60 years. Each patient had a markedly elevated serum anti-Bartonella henselae antibody titer. Visual symptoms developed 2 weeks or less after the onset of systemic symptoms. Lymphadenopathy was detected in one of five patients. Neuroretinitis was found in 4 patients, and papillitis in 1 patient. Seven eyes showed retinochoroidal exudates. Anterior uveitis was observed in three eyes. Four patients received systemic corticosteroids. CONCLUSION: The ocular manifestations of cat scratch disease include neuroretinitis, papillitis, retinochoroidal exudates, and anterior uveitis.