LDL Particle Size Research Articles

Relationship between the estimates of desaturase activities and cardiometabolic phenotypes in Koreans

In the present study, we evaluated the relationships of estimated desaturase activities with cardiometabolic risk factors including abdominal obesity, atherogenic lipoprotein phenotype and inflammation in Koreans. Ninety-three healthy volunteers participated in this cross-sectional study. LDL particle size was determined using gradient gel electrophoresis and inflammatory markers including C-reactive protein, soluble intercellular adhesion molecule-1, and adiponectin were measured. Stearoyl–coA desaturase, delta-6 desaturase and delta-5 desaturase were estimated as precursor to fatty acid ratios. The results showed that stearoyl–coA desaturase was correlated with body mass index (r = 0.235, p<0.05), triglyceride (r = 0.261, p<0.001), and HDL-cholesterol (r = −0.226, p<0.05). Stearoyl–coA desaturase was associated with only triglyceride (r = 0.283, p<0.01). Delta-6 desaturase was correlated with body mass index (r = 0.236, p<0.05), waist circumference (r = 0.218, p<0.05), triglyceride (r = 0.399, p<0.001), C-reactive protein (r = 0.333, p<0.001), soluble intercellular adhesion molecule-1 (r = 0.229, p<0.05), HDL-cholesterol (r = −0.325, p<0.01), LDL particle size (r = −0.297, p<0.01) and adiponectin (r = −0.233, p<0.05). In contrast, delta-5 desaturase was correlated with body mass index (r = −0.324, p<0.01), waist circumference (r = −0.276, p<0.01), triglyceride (r = −0.329, p<0.01), C-reactive protein (r = −0.215, p<0.05), HDL-cholesterol (r = 0.262, p<0.05) and LDL particle size (r = 0.278, p<0.01). Stepwise multiple regression analysis revealed that delta-6 desaturase (p<0.01) together with waist circumference (p<0.001) were found to be independent factors for determining plasma levels of C-reactive protein (R2 = 0.230). Estimated desaturase activities are closely associated with the features of cardiometabolic risk in Koreans.

Observational study of lipid profile and LDL particle size in patients with metabolic syndrome

BackgroundThe atherogenic lipoprotein phenotype is characterized by an increase in plasma triglycerides, a decrease in high-density lipoprotein cholesterol (HDLc), and the prevalence of small, dense-low density lipoprotein cholesterol (LDLc) particles. The aim of this study was to establish the importance of LDL particle size measurement by gender in a group of patients with Metabolic Syndrome (MS) attending at a Cardiovascular Risk Unit in Primary Care and their classification into phenotypes.Subjects and methodsOne hundred eighty-five patients (93 men and 92 women) from several areas in the South of Spain, for a period of one year in a health centre were studied. Laboratory parameters included plasma lipids, lipoproteins, low-density lipoprotein size and several atherogenic rates were determinated.ResultsWe found differences by gender between anthropometric parameters, blood pressure and glucose measures by MS status. Lipid profile was different in our two study groups, and gender differences in these parameters within each group were also remarkable, in HDLc and Apo A-I values. According to LDL particle size, we found males had smaller size than females, and patients with MS had also smaller than those without MS. We observed inverse relationship between LDL particle size and triglycerides in patients with and without MS, and the same relationship between all atherogenic rates in non-MS patients. When we considered our population in two classes of phenotypes, lipid profile was worse in phenotype B.ConclusionIn conclusion, we consider worthy the measurement of LDL particle size due to its relationship with lipid profile and cardiovascular risk.

Prevalence of LDL atherogenic phenotype in patients with systemic lupus erythematosus.

Background:Patients with systemic lupus erythematosus (SLE) are 5–8 times more likely to develop coronary heart disease than the general population. The aim of this study was to find out the prevalence of the small dense low-density lipoprotein (LDL) cholesterol particle in patients with SLE.Methods:We recruited 50 consecutive patients with SLE who had no evidence of hypertension or renal failure. Fifty age- and gender-matched healthy controls were also recruited. We measured serum lipid levels and LDL particle diameters by gradient gel electrophoresis in both patients and controls.Results:Patients with SLE had significant dyslipidemia, characterized by elevated plasma triglycerides, LDL cholesterol, Apoprotein B, triglyceride:high-density (HDL) lipoprotein cholesterol ratio, and decreased plasma concentrations of HDL cholesterol. The LDL particle size in SLE (24.8 ± 1.23 nm) was significantly (P < 0.01) smaller than that in controls (26.1 ± 1.31 nm). The prevalence of the LDL phenotype B (the atherogenic phenotype) was 52% in SLE but only 20% in healthy controls.Conclusion:We conclude that the high prevalence of small dense LDL in SLE may contribute to the high incidence of coronary heart disease seen in this disorder.

Smaller Mean LDL Particle Size and Higher Proportion of Small Dense LDL in Korean Type 2 Diabetic Patients

BackgroundSmall dense low density lipoprotein (sdLDL) has recently emerged as an important risk factor of coronary heart disease.MethodsThe mean LDL particle size was measured in 203 patients with type 2 diabetes mellitus (T2DM) and 212 matched subjects without diabetes using polyacrylamide tube gel electrophoresis. Major vascular complications were defined as stroke, angiographically-documented coronary artery disease or a myocardial infarction. Peripheral vascular stenosis, carotid artery stenosis (≥50% in diameter) or carotid artery plaque were considered minor vascular complications. Overall vascular complications included both major and minor vascular complications.ResultsDiabetic patients had significantly smaller mean-LDL particle size (26.32 nm vs. 26.49 nm) and a higher percentage of sdLDL to total LDL compared to those of subjects without diabetes (21.39% vs. 6.34%). The independent predictors of sdLDL in this study were serum triglyceride level and body mass index (odds ratio [OR], 1.020 with P<0.001 and OR 1.152 with P<0.027, respectively). However, no significant correlations were found between sdLDL and major vascular complications (P=0.342), minor vascular complications (P=0.573) or overall vascular complications (P=0.262) in diabetic subjects.ConclusionDiabetic patients had a smaller mean-LDL particle size and higher proportion of sdLDL compared to those of subjects without diabetes. Obese diabetic patients with hypertriglyceridemia have an increased risk for atherogenic small dense LDL. However, we could not verify an association between LDL particle size and vascular complications in this study.

Medical angioplasty - hope and expectations: an optimistic overview.

Primary and secondary prevention of cardiovascular diseases (CVD) are markedly overlooked worldwide. The use of these kinds of preventive methods will greatly improve outcome of or even reverse major CVD, especially coronary atherosclerosis. Comprehensive lifestyle changes combined with aggressive medical therapy [lipid lowering agents “statins”, antiplatelet agents, beta-blockers and angiotensin-converting enzyme inhibitors] for patients suffering from coronary heart disease significantly reduce all major adverse cardiovascular events (MACE), especially in those with stable coronary artery disease (CAD), even if their coronary lesions are significant. The main mechanistic pathways for the significant reduction of MACE are: Stabilization of atheromatous plaques through endothelial function reparation, strengthening of the fibrous cap of the atheromatous plaque and reduction of atheroma burden, i.e., reversal of the process of coronary artery stenosis, the great dream of “medical angioplasty”. Despite the compelling data indicating the great beneficial effects of both primary and secondary prevention of coronary atherosclerosis, the US national survey data reveals that only a minority of patients eligible by guidelines for these therapies in fact receive them. Hence, we strongly believe that our main duties as cardiologists is to improve the up-to-date knowledge of the practicing physicians about utility of aggressive medical therapy for both prevention and reversal of CVD, and also to promote useful primary and secondary prevention programs among physicians and patients. Meanwhile, further improvement and refinement of the current therapeutic modalities and introduction of new modalities for the management of lipid parameters other than LDL-C, such as HDL-C, triglyceride, lipoprotein (a), LDL particle size and susceptibility to oxidation may add further favourable effects in prevention and reversal of atherosclerotic process. Cardiologists should be just as aggressive with prevention as many have been with intervention. This optimistic overview is a valley cry to all practicing physicians; please depart from usual methods of intervention to preventive strategies which are largely overlooked.

Low-density Lipoprotein Cholesterol/Apolipoprotein B Ratio May Be a Useful Index That Differs in Statin-Treated Patients With and Without Coronary Artery Disease

Low density lipoproteins (LDLs) are heterogeneous aggregations of molecules of different particle sizes, and small-size LDLs are more potent risk factors for atherosclerosis. We examined the qualitative characteristics of LDLs in patients with stable coronary artery disease (CAD) receiving statin therapy. LDL-particle size was estimated based on the LDL-cholesterol/apolipoprotein B ratio (LDL-C/apoB) in 214 age-adjusted men receiving statin therapy. The LDL-C/apoB ratio was significantly lower in the CAD (+) group (n = 107) than in the CAD (-) group (n = 107) (median, 1.17 versus 1.19, P = 0.0095). LDL-C/apoB was significantly lower in patients with serum TG ≥ 150 mg/dL than in those with serum TG < 150 mg/dL, and in patients with serum HDL-C < 40 mg/dL than in those with serum HDL-C ≥ 40 mg/dL (1.06 versus 1.18, P = 0.012; 1.08 versus 1.22, P = 0.0023). Stepwise logistic regression analysis revealed that elevated serum TG was an independent predictor for smaller sizes of LDLs, both in the overall subjects (β : -0.165, P = 0.02) as well as in the subset with serum LDL-C < 100 mg/dL (β : -0.252, P = 0.011). This study demonstrated that not only the absolute serum LDL-C level, but also the qualitative characteristics of LDL may be monitored for secondary prevention of CAD. Such monitoring is particularly important in patients with elevated serum TG levels, which is associated with smaller sizes of LDL-particles.

Small Dense LDL Particles in Relation to LDL Oxidation in Normolipidemic CAD Patients

Aims: Lipid and lipoprotein cholesterol levels are not predictive of coronary artery disease (CAD) risk in all the subjects. The heterogeneity of lipoprotein particles plays an important role in this respect. This fact needs to be studied in normolipidemic CAD patients. The aim of the present study was to evaluate the role of small dense LDL particles in relation to LDL oxidation in normolipidemic coronary artery disease patients. Methods and Results: One hundred and twenty eight CAD patients and 200 age and sex matched normal individuals were studied. Subjects were screened for various biochemical investigations such as lipid profile, serum apoB, LDL apoB carbonyl content, MDA-LDL levels. Log (TG/HDL-C) ratio was taken as an index of LDL particle size. In the present study, lipid levels could not discriminate well between patients and normal subjects. However normolipidemic CAD patients had increased positive values of log (TG/HDL-C) as compared to controls indicating the predominance of small dense LDL particles. This was further supported from the raised serum apoB levels. LDL apoB carbonyl content (LDL protein oxidation) and MDA-LDL levels (LDL lipid peroxidation) were raised in normolipidemic CAD patients as compared to normal subjects. Conclusions: Assessment of LDL particle size and LDL oxidation status might be more predictive of CAD risk even in subjects with normal lipid and lipoprotein cholesterol levels.

Investigation of LRP8 gene in 1p31 QTL linked to LDL peak particle diameter in the Quebec family study

The small, dense LDL phenotype is associated with an increased cardiovascular disease risk. A genome-wide scan performed on 236 nuclear families of the Quebec Family Study (QFS) revealed a quantitative trait locus affecting LDL peak particle diameter (LDL-PPD) and density on the 1p31 region. This region contains the low-density lipoprotein receptor-related protein 8 (LRP8) gene. LRP8, a receptor for apolipoprotein (apo) E, modulates apoE levels, thus contributing to plasma cholesterol and triglyceride (TG) concentrations. We investigate the effects of LRP8 polymorphisms on LDL-PPD, on the relative proportion of small LDL (< 255 Å) and the absolute concentration of cholesterol among the small LDL particles. LRP8 rs5174 was associated with LDL-PPD and estimated cholesterol concentrations in the small LDL particles adjusted for the effects of age and sex ( p = 0.008, p = 0.04, respectively). LRP8 rs3820198 was associated with total and LDL-cholesterol levels as well as with apoB concentrations adjusted for the effects of age and sex ( p = 0.005, p = 0.004 and p = 0.01, respectively) but not with LDL size-related variables. These results suggest that LRP8 gene polymorphisms influence plasma cholesterol levels as well as size and composition of LDL particles.

Effects of lycopene supplementation on oxidative stress and markers of endothelial function in healthy men

ObjectiveThe objective was to determine the effects of lycopene supplementation on endothelial function assessed by reactive hyperemia peripheral arterial tonometry (RH-PAT) and oxidative stress. MethodsHealthy men (n=126) were randomized to receive placebo (n=38), 6mg (n=41), or 15mg (n=37) lycopene daily for 8-week. ResultsSerum lycopene increased in a dose-dependent manner after 8-week supplementation (P<0.001). The 15mg/day group had greater increase in plasma SOD activity (P=0.014) and reduction in lymphocyte DNA comet tail length (P=0.042) than the placebo group. Intragroup comparison revealed a 23% increase in RH-PAT index from baseline (1.45±0.09 vs. 1.79±0.12; P=0.032) in the 15mg/day group after 8-week. hs-CRP, systolic blood pressure, sICAM-1 and sVCAM-1 significantly decreased, and β-carotene and LDL-particle size significantly increased only in the 15mg/day group. Interestingly, the beneficial effect of lycopene supplementation on endothelial function (i.e., RH-PAT and sVCAM-1) were remarkable in subjects with relatively impaired endothelial cell function at initial level. Changes in RH-PAT index correlated with SOD activity (r=0.234, P=0.017) especially in the 15mg lycopene/day group (r=0.485, P=0.003), lymphocyte DNA comet tail moment (r=−0.318, P=0.001), and hs-CRP (r=−0.238, P=0.011). In addition, changes in lycopene correlated with hs-CRP (r=−0.230, P=0.016) and SOD activity (r=0.205, P=0.037). ConclusionAn increase in serum lycopene after supplementation can reduce oxidative stress which may play a role in endothelial function.

Differences in lipoprotein particle subclass distribution for Japanese Americans in Hawaii and Japanese in Japan: The INTERLIPID Study

Current data suggest that low density lipoprotein (LDL) and high density lipoprotein (HDL) subclass concentrations relate directly to the risk of coronary heart disease (CHD). Earlier Studies indicated that Japanese in Japan had lower rates of CHD than Japanese Americans in Hawaii. Rates of CHD appear to continue to be lower in Japan despite increasing cholesterol levels in Japan and decreasing CHD rates in the United States. To provide insight into CHD rate differences. Nuclear Magnetic Resonance (NMR) measurements of lipoprotein subclasses were used to assess lipoprotein particle concentration and size in samples from these two genetically similar populations in Japan and Hawaii. Japanese Americans had significantly higher age- and risk factor- adjusted concentrations of lipoprotein particles implicated in atherogenesis, including large very low density lipoprotein (VLDL; P < 0.001), small LDL (P < 0.001), and small HDL (women, P < 0.001; men, P < 0.01), and significantly lower concentrations of large LDL (P < 0.001) and the putative cardio-protective large HDL (P < 0.05) than Japanese in Japan. Average age- and risk factor- adjusted LDL and HDL particle sizes were also significantly (P < 0.001) smaller in Japanese Americans. Adjustment for body mass index markedly reduced the differences in some lipoprotein measures, including total LDL and large HDL particle concentrations for both genders, total VLDL particle concentration for women, and large VLDL concentration and average HDL particle size for men. Differences in lipoprotein subclass distributions and lifestyle factors such as body weight may contribute to differences in CHD incidence for Japanese in Japan and Japanese Americans.

Treating diabetic dyslipidemia: What have we learnt from recent clinical trials?

Treating diabetic dyslipidemia: What have we learnt from recent clinical trials?

Triglyceride/High-Density Lipoprotein Cholesterol Ratio

Insulin resistance, changes in lipid parameters, and cardiometabolic adverse events have been reported in some patients during clinical trials of antipsychotic agents. The present study examined whether the triglyceride/high-density lipoprotein (HDL) ratio can be used as a better surrogate than other conventional lipid measures (low-density lipoprotein [LDL], HDL, triglyceride) in predicting insulin resistance and LDL particle size in nondiabetic patients with schizophrenia. Outpatients 18 to 75 years old diagnosed with schizophrenia or schizoaffective disorder (DSM-IV criteria) and receiving olanzapine, risperidone, or typical antipsychotics participated in a multicenter, cross-sectional study. Fasting blood samples were obtained to determine the levels of glucose, insulin, lipids, and lipid particle size. The study was conducted from July 2001 to March 2002. In the sample of 206 patients, significant correlations were found between various lipid measures (LDL, HDL, triglyceride, and triglyceride/HDL ratio) and the homeostasis model of assessment of insulin resistance (P < .05). However, stepwise multiple regression analysis suggested that the triglyceride/HDL ratio is a stronger predictor of insulin resistance and of LDL particle size than other conventional lipoprotein measures after other potential confounding variables, including age, gender, race, family history of diabetes, body mass index, and antipsychotic agent, were taken into consideration (P < .001). Further, logistic regression analysis indicated that the triglyceride/HDL ratio and male gender predict the existence of a small LDL particle size pattern (pattern B LDL phenotype), with a sensitivity of 75.9% and a specificity of 85.4%. The triglyceride/HDL ratio, a simple, readily available and inexpensive measure, can be a useful surrogate to identify those with insulin resistance as well as those with more atherogenic small LDL particles in nondiabetic patients with schizophrenia.

Effect of Non-Statin Lipid Lowering and Anti-Obesity Drugs on LDL Subfractions in Patients with Mixed Dyslipidaemia

Small, dense low density lipoprotein (sdLDL) particles are considered an emerging cardiovascular risk factor. Obese patients with mixed dyslipidaemia frequently have elevated sdLDL cholesterol (sdLDL-C) levels. Therefore, agents that favourably modulate the LDL phenotype may be of clinical value in these patients. We review the efficacy of anti-obesity and lipid lowering drugs other than statins on LDL subfractions in patients with mixed dyslipidaemia primarily focusing on those who are overweight/obese. The literature search was based on PubMed listings up to 26 November 2009. In most studies ezetimibe decreases the large and medium LDL subclasses and, to a lesser extent, the sdLDL particles, while it does not substantially influence LDL size. Fibrates and niacin reduce sdLDL particles and shift LDL size towards large, buoyant LDL particles. More studies are needed to elucidate the effects of fish oils and resins on LDL phenotype. Orlistat and rimonabant have been associated with reductions in sdLDL-C levels along with an increase in LDL particle size. We did not find any literature describing the effect of sibutramine on sdLDL profile. Treatment with fibrates and niacin seems to be beneficial in patients with mixed dyslipidaemia. The addition of orlistat may further improve LDL phenotype in overweight/obese patients.

Changes in lipoprotein(a), oxidized phospholipids, and LDL subclasses with a low-fat high-carbohydrate diet

Low-fat diets have been shown to increase plasma concentrations of lipoprotein(a) [Lp(a)], a preferential lipoprotein carrier of oxidized phospholipids (OxPLs) in plasma, as well as small dense LDL particles. We sought to determine whether increases in plasma Lp(a) induced by a low-fat high-carbohydrate (LFHC) diet are related to changes in OxPL and LDL subclasses. We studied 63 healthy subjects after 4 weeks of consuming, in random order, a high-fat low-carbohydrate (HFLC) diet and a LFHC diet. Plasma concentrations of Lp(a) (P < 0.01), OxPL/apolipoprotein (apo)B (P < 0.005), and OxPL-apo(a) (P < 0.05) were significantly higher on the LFHC diet compared with the HFLC diet whereas LDL peak particle size was significantly smaller (P < 0.0001). Diet-induced changes in Lp(a) were strongly correlated with changes in OxPL/apoB (P < 0.0001). The increases in plasma Lp(a) levels after the LFHC diet were also correlated with decreases in medium LDL particles (P < 0.01) and increases in very small LDL particles (P < 0.05). These results demonstrate that induction of increased levels of Lp(a) by an LFHC diet is associated with increases in OxPLs and with changes in LDL subclass distribution that may reflect altered metabolism of Lp(a) particles.

FADS gene polymorphisms in Koreans: Association with ω6 polyunsaturated fatty acids in serum phospholipids, lipid peroxides, and coronary artery disease

ObjectiveWe investigated the association of polymorphisms in FADS genes with polyunsaturated fatty acids (PUFAs) in serum phospholipids, lipid peroxides, and coronary artery disease (CAD) in Koreans. MethodsIn this case–control study, CAD patients (n=756, 40–79 years) and healthy controls (n=890) were genotyped for rs174537 near FADS1 (FEN1 rs174537G>T), FADS2 (rs174575, rs2727270), and FADS3 (rs1000778). We calculated the odds ratios (ORs) for CAD risk and measured serum PUFA composition and lipid peroxide. ResultsAmong four SNPs, only rs174537G>T differed in allele frequencies between controls and CAD patients after adjustment for age, BMI, cigarette smoking, alcohol consumption, hypertension, diabetes mellitus, and hyperlipidemia (P=0.017). The minor T allele was associated with a lower risk of CAD [OR 0.75 (95%CI 0.61–0.92), P=0.006] after adjustment. rs174537T carriers had a significantly higher proportion of linoleic acid (LA, 18:2ω6), lower arachidonic acid (AA, 20:4ω6), and lower ratios of AA/dihomo-γ-linolenic acid (DGLA, 20:3ω6) and AA/LA than G/G subjects in both control and CAD groups. In the control group, 174537T carriers had significantly lower levels of total- and LDL-cholesterol, malondialdehyde, and ox-LDL. In CAD patients, rs174537T carriers showed a larger LDL particle size than G/G subjects. The proportion of AA in serum phospholipids positively correlated with LDL-cholesterol, ox-LDL, and malondialdehyde in controls and with 8-epi-prostaglandin F2α in both control and CAD groups. ConclusionThe rs174537T is associated with a lower proportion of AA in serum phospholipids and reduced CAD risk, in association with reduced total- and LDL-cholesterol and lipid peroxides.

Improvements in LDL particle size and distribution by short-term alternate day modified fasting in obese adults

Alternate day modified fasting (ADMF) beneficially modulates several indicators of CHD risk, but its effects on LDL particle size have never been tested. Accordingly, we examined the effects of ADMF on LDL particle size and distribution in obese adults. Sixteen obese subjects participated in a 10-week trial with three consecutive phases: (1) 2-week control phase; (2) 4-week ADMF controlled feeding phase; (3) 4-week ADMF self-selected feeding phase. After 8 weeks of diet, body weight and waist circumference were reduced (P<0·05) by 5·6 (sem 0·9)kg and 4·0 (sem 0·9)cm, respectively. LDL-cholesterol and TAG concentrations decreased (P<0·05) by 25 (sem 10)% and 32 (sem 6)%, respectively. Peak LDL particle size increased (P<0·05) from 266 (sem 1) to 268 (sem 1)Å. Additionally, the proportion of small LDL particles decreased (P<0·05) from 13 (sem 2)% to 9 (sem 3)%, while the proportion of large LDL particles increased (P<0·05) from 68 (sem 4)% to 76 (sem 4)% post-treatment. These findings suggest that ADMF is an effective diet strategy for increasing LDL particle size and decreasing the proportion of small, dense LDL particles in obese adults.

Lipid metabolism in long-lived families: the Leiden Longevity Study

Mechanisms underlying the variation in human life expectancy are largely unknown, but lipid metabolism and especially lipoprotein size was suggested to play an important role in longevity. We have performed comprehensive lipid phenotyping in the Leiden Longevity Study (LLS). By applying multiple logistic regression analysis we tested for the first time the effects of parameters in lipid metabolism (i.e., classical serum lipids, lipoprotein particle sizes, and apolipoprotein E levels) on longevity independent of each other. Parameters in lipid metabolism were measured in offspring of nonagenarian siblings from 421 families of the LLS (n = 1,664; mean age, 59 years) and in the partners of the offspring as population controls (n = 711; mean age, 60 years). In the initial model, where lipoprotein particles sizes, classical serum lipids and apolipoprotein E were included, offspring had larger low-density lipoprotein (LDL) particle sizes (p = 0.017), and lower triglyceride levels (p = 0.026), indicating that they displayed a more beneficial lipid profile. After backwards regression only LDL size (p = 0.014) and triglyceride levels (p = 0.05) were associated with offspring from long-lived families. Sex-specific backwards regression analysis revealed that LDL particle sizes were associated with male longevity (increase in log odds ratio (OR) per unit = 0.21; p = 0.023). Triglyceride levels (decrease OR per unit = 0.22; p = 0.01), but not LDL particle size, were associated with female longevity. Due to the analysis of a comprehensive lipid profile, we confirmed an important role of lipid metabolism in human longevity, with LDL size and triglyceride levels as major predicting factors.

Severely modified lipoprotein properties without a change in cholesteryl ester transfer protein activity in patients with acute renal failure secondary to Hantaan virus infection

Patients with hemorrhagic fever with renal syndrome (HFRS) often exhibit altered serum lipid and lipoprotein profile during the oliguric phase of the disease. Serum lipid and lipoprotein profiles were assessed during the oliguric and recovery phases in six male patients with HFRS. In the oliguric phase of HFRS, the apolipoprotein (apo) C-III content in high-density lipoproteins (HDL) was elevated, whereas the apoA-I content was lowered. The level of expression and activity of antioxidant enzymes were severely reduced during the oliguric phase, while the cholesteryl ester transfer protein activity and protein level were unchanged between the phases. In the oliguric phase, electromobility of HDL2 and HDL3 was faster than in the recovery phase. Low-density lipoprotein (LDL) particle size was smaller and the distribution was less homogeneous. Patients with HFRS in the oliguric phase had severely modified lipoproteins in composition and metabolism.

Measurement of lipoprotein particle sizes using dynamic light scattering

A simple method for the measurement of LDL particle sizes is needed in clinical laboratories because a predominance of small, dense LDL (sd LDL) has been associated with coronary heart disease. We applied dynamic light scattering (DLS) to measure lipoprotein particle sizes, with special reference to sd LDL. Human serum lipoproteins isolated by a combination of ultracentrifugation and gel chromatography, or by sequential ultracentrifugation, were measured for particle size using DLS. The sizes of polystyrene beads, with diameters of 21 and 28 nm according to the manufacturer, were determined by DLS as 19.3 +/- 1.0 nm (mean +/- SD, n = 11) and 25.5 +/- 1.0 nm, respectively. The coefficients of variation for the 21 and 28 nm beads were 5.1% and 3.8% (within-run, n = 11), and 2.9% and 6.2% (between-run, n = 3), respectively. The lipoprotein sizes determined by DLS for lipoprotein fractions isolated by chromatography were consistent with the elution profile. Whole serum, four isolated lipoprotein fractions (CM + VLDL + IDL, large LDL, sd LDL and HDL) and a non-lipoprotein fraction isolated by sequential ultracentrifugation were determined by DLS to be 13.1 +/- 7.5, 37.0 +/- 5.2, 21.5 +/- 0.8, 20.3 +/- 1.1, 8.6 +/- 1.5 and 8.8 +/- 2.0 nm, respectively. The proposed DLS method can differentiate the sizes of isolated lipoprotein particles, including large LDL and sd LDL, and might be used in clinical laboratories in combination with convenient lipoprotein separation.

Association of serum lycopene and brachial-ankle pulse wave velocity with metabolic syndrome

Metabolic syndrome (MetS) is known to inversely correlate with antioxidant status. Recently, it has been reported that MetS is associated with arterial stiffness, a composite risk factor for early atherosclerosis. In addition, our recent study for healthy women showed an inverse relationship between arterial stiffness and circulating lycopene. Therefore, this study aimed to investigate the interrelationship between arterial stiffness, antioxidant status, and the risk of MetS. Korean men (N = 299) were subgrouped according to the number of MetS risk factors (RF 0, RF 1-2, RF ≥3). Anthropometric parameters, brachial-ankle pulse wave velocity (baPWV; a marker of arterial stiffness), antioxidants (lycopene, β-carotene, α-tocopherol), lipid profiles, glucose, insulin, and oxidative stress (low-density lipoprotein [LDL] particle size, oxidized LDL) were measured. Corresponding to the number of MetS RF, baPWV (1306 ± 17, 1364 ± 16, and 1420 ± 33 cm/s; P < .001) and insulin resistance (1.5 ± 0.1, 1.9 ± 0.1, and 2.7 ± 0.2; P < .001) gradually increased after adjustment for age, body mass index, smoking, and drinking, whereas serum lycopene among antioxidants and LDL particle size gradually decreased (0.036 ± 0.001, 0.031 ± 0.001, and 0.028 ± 0.001 mmol/L; P = .004 and 23.9 ± 0.1, 23.7 ± 0.1, and 23.3 ± 0.1 nm; P < .001, respectively). Brachial-ankle pulse wave velocity inversely correlated with serum lycopene after adjustment for the above confounders, blood pressure, insulin resistance, and oxidative stress ( r = −0.136, P < .05). Oxidative stress markers also significantly correlated with baPWV as well as serum lycopene. Study subjects were divided into 2 groups by the median level of serum lycopene. When serum lycopene was lower than median level (≤0.0294 mmol/L), baPWV was significantly higher in MetS subjects than non-MetS subjects (1436 ± 41 vs 1367 ± 23 cm/s) after adjustment for age, body mass index, smoking, drinking, and oxidative stress ( P = .041). However, when serum lycopene levels were high, no statistically significant difference was observed between the 2 subject groups (1386 ± 36 vs 1326 ± 13 cm/s). In conclusion, our result shows the interrelationship between circulating lycopene, baPWV, and MetS. In addition, much enhanced baPWV in MetS may be associated with lower lycopene concentration.