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

Abstract

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 ( = 0.727, < 0.01). Serum HTGL concentrations showed positive correlations to serum TGs ( = 0.314, < 0.05) and alanine aminotransferase ( = 0.406, < 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.

Association between skeletal muscle mass and serum concentrations of lipoprotein lipase, GPIHBP1, and hepatic triglyceride lipase in young Japanese men

“…A Human GPIHBP1 Assay Kit (IBL) based on sandwich ELISA was used to determine serum GPIHBP1 concentrations [36]. Finally, the Human Serum HTGL ELISA Kit (IBL) was used to measure serum HTGL concentrations [34].…”

“…In the past, owing to the low sensitivities of assays, previous methods used for measuring circulating activities and concentrations of lipases required heparin administration. Therefore, assay methods based on the monoclonal antibodies against these lipases have been developed recently to achieve sufficient sensitivities for measurement of serum LPL and HTGL concentrations without the need for heparin administration [32–34]. As a result, preheparin serum LPL concentrations can now be measured using a latex particle-enhanced turbidimetric immunoassay with an automated analyzer [35], and preheparin serum HTGL concentrations can be determined using high-sensitivity HTGL enzyme-linked immunosorbent assay (ELISA) [34].…”

Serum Triglyceride Lipase Concentrations are Independent Risk Factors for Coronary Artery Disease and In-Stent Restenosis

“…The serum EL concentration was measured using the EL-ELISA (enzyme linked immunosorbent assay) developed by Ishida et al 20) . Serum HL concentration was determined by HL-ELISA developed by Miyashita et al 12) . Serum LPL concentration was measured by LPL-ELISA described by Shirakawa et al 21) .…”

“…It has been reported that low plasma HL activity is associated with hypertriglyceridemia and CAD 10, 11) . However, high serum HL concentration is associated with increased CAD risk 12) . LPL is mainly expressed in adipose tissue, skeletal, and cardiac muscle, and catalyzes the hydrolysis of triglycerides in circulating lipoproteins 5) .…”

“…In addition, it is suggested that combining multiple risk factors can be more accurately and efficiently quantified to identify patients at risk for CAD 17) . Considering the fact that heparin injection is not quite standardized and accepted by patients and may also affect lipoprotein metabolism 12, 18) , in our study, we chose to detect the serum concentrations of lipases without heparin administration. We tested the hypothesis that serum EL, HL, and LPL concentrations would all be simultaneous independent risk factors for CAD and when combined the three lipases would provide the higher predictive power than HDL-c or LDL-c for CAD.…”