Increased LDL oxidation is associated with coronary artery disease. The predictive value of circulating oxidized LDL is additive to the Global Risk Assessment Score for cardiovascular risk prediction based on age, gender, total and HDL cholesterol, diabetes, hypertension, and smoking. Circulating oxidized LDL does not originate from extensive metal ion-induced oxidation in the blood but from mild oxidation in the arterial wall by cell-associated lipoxygenase and/or myeloperoxidase. Oxidized LDL induces atherosclerosis by stimulating monocyte infiltration and smooth muscle cell migration and proliferation. It contributes to atherothrombosis by inducing endothelial cell apoptosis, and thus plaque erosion, by impairing the anticoagulant balance in endothelium, stimulating tissue factor production by smooth muscle cells, and inducing apoptosis in macrophages. HDL cholesterol levels are inversely related to risk of coronary artery disease. HDL prevents atherosclerosis by reverting the stimulatory effect of oxidized LDL on monocyte infiltration. The HDL-associated enzyme paraoxonase inhibits the oxidation of LDL. PAF-acetyl hydrolase, which circulates in association with HDL and is produced in the arterial wall by macrophages, degrades bioactive oxidized phospholipids. Both enzymes actively protect hypercholesterolemic mice against atherosclerosis. Oxidized LDL inhibits these enzymes. Thus, oxidized LDL and HDL are indeed antagonists in the development of cardiovascular disease.

Oxidized LDL and HDL: antagonists in atherothrombosis

http://image.sciencenet.cn/olddata/kexue.com.cn/upload/blog/file/2009/2/2009210203125328133.pdf

Supplementation of hydrogen-rich water improves lipid and glucose metabolism in patients with type 2 diabetes or impaired glucose tolerance.

Cocoa powder is rich in polyphenols, such as catechins and procyanidins, and has been shown in a variety of subject models to inhibit oxidized LDL and atherogenesis. Our study evaluated plasma LDL cholesterol and oxidized LDL concentrations following the intake of different levels of cocoa powder (13, 19.5, and 26 g/d) in normocholesterolemic and mildly hypercholesterolemic humans. In this comparative, double-blind study, we examined 160 subjects who ingested either cocoa powder containing low-polyphenolic compounds (placebo-cocoa group) or 3 levels of cocoa powder containing high-polyphenolic compounds (13, 19.5, and 26 g/d for low-, middle-, and high-cocoa groups, respectively) for 4 wk. The test powders were consumed as a beverage after the addition of hot water, twice each day. Blood samples were collected at baseline and 4 wk after intake of the test beverages for the measurement of plasma lipids. Plasma oxidized LDL concentrations decreased in the low-, middle-, and high-cocoa groups compared with baseline. A stratified analysis was performed on 131 subjects who had a LDL cholesterol concentrations of > or =3.23 mmol/L at baseline. In these subjects, plasma LDL cholesterol, oxidized LDL, and apo B concentrations decreased, and the plasma HDL cholesterol concentration increased, relative to baseline in the low-, middle-, and high-cocoa groups. The results suggest that polyphenolic substances derived from cocoa powder may contribute to a reduction in LDL cholesterol, an elevation in HDL cholesterol, and the suppression of oxidized LDL.

Plasma LDL and HDL Cholesterol and Oxidized LDL Concentrations Are Altered in Normo- and Hypercholesterolemic Humans after Intake of Different Levels of Cocoa Powder

Immunoassays are bioanalytical methods in which the quantitation of the analyte depends on the reaction of an antigen (analyte) and an antibody. Immunoassays have been widely used in many important areas of pharmaceutical analysis such as diagnosis of diseases, therapeutic drug monitoring, clinical pharmacokinetic and bioequivalence studies in drug discovery and pharmaceutical industries. The importance and widespread of immunoassay methods in pharmaceutical analysis are attributed to their inherent specificity, high-throughput, and high sensitivity for the analysis of wide range of analytes in biological samples. Recently, marked improvements were achieved in the field of immunoassay development for the purposes of pharmaceutical analysis. These improvements involved the preparation of the unique immunoanalytical reagents, analysis of new categories of compounds, methodology, and instrumentation. The basic methodologies and recent advances in immunoassay methods applied in different fields of pharmaceutical analysis have been reviewed.

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Immunoassay Methods and their Applications in Pharmaceutical Analysis: Basic Methodology and Recent Advances.

Oxidized low-density lipoprotein (OxLDL) has been shown to exist in human circulating plasma. Several groups including ours have developed methods for immunologically measuring OxLDL, which have been applied to several clinical, both cross-sectional and prospective, studies. These data clearly show that OxLDL levels correlate well with the severity of cardiovascular diseases. In particular, recent observations suggest that plasma OxLDL levels could be a useful marker for predicting future cardiovascular events; however, substantial differences exist among the different methods of OxLDL measurement. To evaluate the clinical data on circulating OxLDL, a proper understanding of the similarity, differences, and limitation of the methods is needed. This paper summarizes the characteristics of the methods used and recent clinical findings.

https://www.jstage.jst.go.jp/article/jat/14/1/14_1_1/_pdf

Measurement of plasma oxidized low-density lipoprotein and its clinical implications.

Simple and practical sandwich-type enzyme immunoassay for human oxidatively modified low density lipoprotein using antioxidized phosphatidylcholine monoclonal antibody and antihuman apolipoprotein-B antibody

We report the development of an EIA specific for antituberculosis antibody in human serum for the clinical evaluation of tuberculosis. We developed a TLC immunostaining method to detect specific antigens for antibodies in the serum of patients with tuberculosis. The detected specific antigens, TDM and specific gylcolipid fraction, were individually purified from M. tuberculosis H37Rv by column chromatography. The two purified fractions were mixed and the mixture, termed TBGL antigen, was applied to an enzyme immunoassay suitable for the measurement of antituberculosis antibodies in serum. This EIA meets all the requirements of routine clinical assay in terms of sensitivity (detection limit: 0.125 U/ml), reproducibility (total CV : 3.3-6.0%), accuracy (recovery: 96-105%), simplicity and rapidity (< 2.5 h). Clinical validation of the assay was confirmed by the measurement of the anti-tuberculosis antibody in the serum of normal subjects and patients with pulmonary tuberculosis. The EIA tested in this study showed a high serodiagnostic discriminating power (90% sensitivity and 98% specificity).

Enzyme immunoassay to detect antituberculous glycolipid antigen (anti-TBGL antigen) antibodies in serum for diagnosis of tuberculosis.

A denatured lipoprotein excellent in long-term storage stability (i.e., scarcely undergoing protein denaturation) which is to be used as a standard in quantitating a denatured protein in blood or assaying physiological activity. The process for producing this stabilized denatured lipoprotein comprises artificially denaturing a lipoprotein and freeze-drying the denatured lipoprotein thus obtained; or treating a solution containing a denatured lipoprotein to a process involving at least one freezing step to thereby denature the lipoprotein contained in the solution and further freeze-drying the denatured lipoprotein thus obtained.

Stabilized denatured lipoprotein and process for producing the same

Cette invention se rapporte a une lipoproteine denaturee ayant une excellente stabilite a la conservation sur une longue periode (c'est-a-dire qu'elle ne subit guere de denaturation de la proteine), a utiliser comme norme de reference lors de la quantification d'une proteine denaturee dans le sang ou lors du dosage d'une activite physiologique. Le procede de production de cette lipoproteine denaturee stabilisee consiste: a denaturer artificiellement une lipoproteine et a lyophiliser la lipoproteine denaturee ainsi obtenue; ou a traiter une solution contenant une lipoproteine denaturee en la soumettant a un procede comprenant au moins une etape de congelation, en vue de denaturer la lipoproteine contenue dans la solution, puis a lyophiliser la lipoproteine denaturee ainsi obtenue.

Nobuyuki Sueshige

Papers

Simple and practical sandwich-type enzyme immunoassay for human oxidatively modified low density lipoprotein using antioxidized phosphatidylcholine monoclonal antibody and antihuman apolipoprotein-B antibody

Enzyme immunoassay to detect antituberculous glycolipid antigen (anti-TBGL antigen) antibodies in serum for diagnosis of tuberculosis.

Stabilized denatured lipoprotein and process for producing the same

Lipoproteine denaturee stabilisee et procede de production de cette lipoproteine