Measurement of cholesterol levels of lipoprotein subclasses in human serum using anion-exchange high-performance liquid chromatography with a linear concentration gradient of sodium perchlorate.

Background: Relationships between the subclasses of high-density lipoprotein (HDL) or low-density lipoprotein (LDL) and the risk of atherosclerotic cardiovascular disease have been studied, and using various methods, such as ultracentrifugation, electrophoresis, and nuclear magnetic resonance, for analysing lipoprotein subclasses. We established a method for HDL and LDL subclasses using anion-exchange high-performance liquid chromatography (AEX-HPLC) with a linear concentration gradient of sodium perchlorate (NaClO).

Method: In the AEX-HPLC, the subclasses of HDL and LDL were separated, and detected using a post-column reactor with an enzymatic cholesterol reagent, that contained cholesterol esterase, cholesterol oxidase, and peroxidase as major ingredients.

Evaluation of the two-point calibration bromocresol green method, showing reduced deviation from the bromocresol purple method in sera from patients with hypoalbuminemia.

Background: The bromocresol green (BCG) and bromocresol purple (BCP) methods are widely used for albumin measurements in routine testing, but the BCG method is known to react with globulin fractions and to have low specificity for albumin. We evaluated a calibration method using different concentrations of human serum albumin standards (two-point calibration BCG method) with the aim of reducing the effect of globulin fractions on the BCG method in patients with hypoalbuminemia.

Method: In the two-point calibration BCG method, two concentrations of standard solutions and their calibration values are set based on the difference in albumin concentrations measured by the BCG method (BCG-HSA method) and the modified BCP (modified BCP-HSA method) calibrated with human serum albumin standard solution (HSA).

Postprandial fatty acid metabolism with coconut oil in young females: a randomized, single-blind, crossover trial.

Background: Approximately 84% of the fatty acids contained in coconut oil (CO) are saturated fatty acids (SFAs), and approximately 47% of the SFA are lauric acid with 12 carbon atoms. Lauric acid carbon chain length is intermediate between medium and long-chain fatty acids (LCFAs). We examined how CO acts on lipid-related substances in the blood to determine whether its properties were similar to medium-chain fatty acids (MCFAs) or LCFAs.

Clinical Significance of Intermediate-Density Lipoprotein Cholesterol Determination as a Predictor for Coronary Heart Disease Risk in Middle-Aged Men.

Not only low-density lipoprotein (LDL) cholesterol but also non-high-density lipoprotein cholesterol (non-HDL-C), very low-density lipoprotein (VLDL) cholesterol (VLDL-C), and intermediate-density lipoprotein (IDL) cholesterol (IDL-C) are reported to be significant risk markers for coronary heart disease (CHD). We reported the relevance of IDL-C to Framingham risk score (F-score), but the present study addressed the relevance of IDL-C to Suita score (S-score), a risk score for coronary heart disease (CHD) developed for the Japanese individuals in addition to F-score. The cholesterol levels of lipoproteins, including triglyceride (TG)-rich lipoproteins (IDL and VLDL), were measured by an anion exchange high-performance liquid chromatography (AEX-HPLC).

Verification of Low-Density Lipoprotein Cholesterol Levels Measured by Anion-Exchange High-Performance Liquid Chromatography in Comparison with Beta Quantification Reference Measurement Procedure.

Background: A new lipoprotein testing method based on anion-exchange HPLC (AEX-HPLC) was recently established. We verified the accuracy of LDL-C levels, a primary therapeutic target for the prevention of cardiovascular disease (CVD), measured by AEX-HPLC comparing with LDL-C levels measured by beta quantification-reference measurement procedure (BQ-RMP), homogenous assays, and calculation methods.

Methods: We compared LDL-C levels measured by AEX-HPLC (adLDL-Ch: LDL-Ch and IDL-Ch) and BQ-RMP using blood samples from 52 volunteers.

Diabetic dyslipidemia: evaluation and mechanism.

Diabetes is one of the well-established independent risk factors for cardiovascular diseases. Diabetes induces dyslipidemia which is characterized by elevated fasting triglyceride (TG) and reduced high-density lipoprotein-cholesterol (HDL-C), and such diabetic dyslipidemia is a crucial determinant for atherogenesis and atherosclerotic progression in patients with diabetes. Previous measurement methods of lipoproteins have problems including time-consuming (ultracentrifugation) and inaccurate and impossible measurements of TG-rich lipoproteins such as chylomicron, intermediate-density lipoprotein (IDL) and very low-density lipoprotein (VLDL).

Innovatively Established Analysis Method for Lipoprotein Profiles Based on High-Performance Anion-Exchange Liquid Chromatography.

Separation analysis of lipoprotein classes have various methods, including ultracentrifugation, electrophoresis, and gel permeation chromatography (GPC). All major lipoprotein classes can be separated via ultracentrifugation, but performing the analysis takes a long time. Low-density lipoprotein (LDL), intermediate-density lipoprotein (IDL), and very low-density lipoprotein (VLDL) in patient samples cannot be sufficiently separated via electrophoresis or GPC.

Cholesterol concentrations in lipoprotein fractions separated by anion-exchange-high-performance liquid chromatography in healthy dogs and dogs with hypercholesterolemia.

Anion-exchange (AEX)-high-performance liquid chromatography (HPLC) for measurement of cholesterol can be used to separate serum lipoproteins (high-density lipoprotein (HDL); low-density lipoprotein (LDL); intermediate-density lipoprotein (IDL); very-low-density lipoprotein (VLDL)) in humans. However, AEX-HPLC has not been applied in veterinary practice. We had three objectives: (i) the validation of AEX-HPLC methods including the correlation of serum cholesterol concentration in lipoprotein fraction measured by AEX-HPLC and gel permeation-HPLC (GP-HPLC) in healthy dogs and those with hypercholesterolemia was investigated; (ii) the reference intervals of lipoprotein fractions measured by AEX-HPLC from healthy dogs (n=40) was established; (iii) lipoprotein fractions from the serum of healthy dogs (n=12) and dogs with hypercholesterolemia (n=23) were compared.

Cholesterol Levels of Six Fractionated Serum Lipoproteins and its Relevance to Coronary Heart Disease Risk Scores.

Aim: Evaluation of serum lipoprotein profiles including triglyceride (TG)-rich lipoprotein, that is, intermediate-density lipoprotein (IDL), very low-density lipoprotein (VLDL), and chylomicron (CM) remnant is important to manage coronary heart disease (CHD) risk. The purpose of this study was to investigate CHD or cardiovascular disease (CVD) risk scores with cholesterol levels of six fractionated lipoprotein classes {high-density lipoprotein [HDL], low-density lipoprotein [LDL], IDL, VLDL, CM including CM remnant, and lipoprotein (a) [Lp (a)]} in Japanese healthy men.

Methods: The present study enrolled 161 healthy men without any medications.

Effect of dietary modification by calorie restriction on cholesterol levels in lipoprotein(a) and other lipoprotein classes.

Background Dietary habits are associated with obesity which is a risk factor for coronary heart disease. The objective is to estimate the change of lipoprotein(a) and other lipoprotein classes by calorie restriction with obesity index and Framingham risk score. Methods Sixty females (56 ± 9 years) were recruited.

Plasma concentration of serotonin is a novel biomarker for coronary microvascular dysfunction in patients with suspected angina and unobstructive coronary arteries.

Aims: Although the importance of coronary microvascular dysfunction (CMD) has been emerging, reliable biomarkers for CMD remain to be developed. We examined the potential usefulness of plasma concentration of serotonin to diagnose CMD in patients with suspected angina and unobstructive coronary arteries.

Methods And Results: We enrolled 198 consecutive patients (M/F 116/82, 60.

Serotonin in peripheral blood reflects oxidative stress and plays a crucial role in atherosclerosis: Novel insights toward holistic anti-atherothrombotic strategy.

We enrolled 132 outpatients with cardiovascular risk factors to evaluate the serotonin levels in platelet-poor plasma (PPP) and whole blood (WB). PPP serotonin levels and PPP/WB serotonin ratio were significantly correlated with levels of oxidative stress measured by derivative reactive oxygen metabolites (d-ROM). Twenty-five subjects were revealed to have stable coronary artery disease (CAD), and the levels CRP, d-ROM, and PPP/WB serotonin ratio were significantly higher in subjects with CAD than in those without CAD.

[Fundamental Evaluation and Clinical Usefulness of Lipoprotein Analysis System with Anion-Exchange Chromatography].

We established a method for measurement of the cholesterol concentrations of high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), intermediate density lipoprotein cholesterol (IDL-C) and very low density lipoprotein cholesterol (VLDL-C) by using high performance liquid chromatography (HPLC) with anion-exchange column. The HPLC method has been covered by insurance in 2013, and HLC-729LPII (LPII) system constructed by this method has come on the market in 2014. We evaluated the fundamental precision data of lipoprotein cholesterol values measured by HLC-729 LPII.

Blood levels of serotonin are specifically correlated with plasma lysophosphatidylserine among the glycero-lysophospholipids.

Backgrounds: Glycero-lysophospholipids (glycero-LPLs), which are known to exert potent biological activities, have been demonstrated to be secreted from activated platelets in vitro; however, their association with platelet activation in vivo has not been yet elucidated. In this study, we investigated the correlations between the blood levels of each glycero-LPL and serotonin, a biomarker of platelet activation, in human subjects to elucidate the involvement of platelet activation in glycero-LPLs in vivo.

Methods And Results: We measured the plasma serotonin levels in 141 consecutive patients undergoing coronary angiography (acute coronary syndrome, n = 38; stable angina pectoris, n = 71; angiographically normal coronary arteries, n = 32) and investigated the correlations between the plasma levels of serotonin and glycero-LPLs.

[Differences in Measured Values among Homogenous Assay Reagents of LDL-C in LP-X Positive Serum Samples].

The LDL-C level measures with homogeneous (direct) assays in almost of clinical laboratories. Several reports however showed differences in measured values among the assay reagents. We investigated the differences in LDL-C values among direct assays and Friedewald formula (F-f) in 58 LP-X positive serum samples from jaundice patients by comparing LDL-C values measured by anion-exchange chromatography (AEX-HPLC), largely comparable to ultracentrifugation method.

A rapid anion-exchange chromatography for measurement of cholesterol concentrations in five lipoprotein classes and estimation of lipoprotein profiles in male volunteers without overt diseases.

Background: Analysis of lipoprotein profile gives important clinical information for lipid-lowering therapy which prevents atherosclerotic diseases. The lipoprotein classes can be isolated from serum with ultracentrifugation, which inevitably consumes a long time and needs large serum volume. We have established a method with anion-exchange chromatography with 1.

Automated measurement method for the determination of vitamin E in plasma lipoprotein classes.

In a subendothelial space of atherosclerotic arteries, apolipoprotein B-containing lipoproteins are accumulated and oxidized, and the oxidized lipoproteins promote macrophage foam cell formation. Therefore, the analysis of vitamin E, a major antioxidant in lipoproteins, is important for understanding atherosclerotic pathogenesis. A new method for the automated measurement of vitamin-E (γ- and α-tocopherols) in plasma HDL, LDL, and VLDL was established by using anion-exchange-chromatography for separation of lipoproteins, reverse-phase-chromatography for separation of γ- and α-tocopherols in each of lipoproteins, and fluorescent detection.

Relevance of intermediate-density lipoprotein cholesterol to Framingham risk score of coronary heart disease in middle-aged men with increased non-HDL cholesterol.

Background: Cholesterol levels of non-high-density lipoprotein (non-HDL), which contains low-density lipoprotein (LDL), intermediate-density lipoprotein (IDL), very low-density lipoprotein (VLDL) and chylomicron (CM) remnant, have been proven to perform a significant predictor of coronary heart disease (CHD) better than LDL-cholesterol regardless of triglyceride (TG) levels. The present study investigated the relevance of TG-rich lipoproteins (IDL, VLDL, CM) to Framingham risk score (FRS) predictive of 10-year CHD risk.

Methods: Lipoprotein profiles (cholesterol levels of HDL, LDL, IDL, VLDL, CM) in Japanese men (n = 487) who underwent medical check-up were determined by using our developed anion-exchange high performance liquid chromatography (AEX-HPLC).