Lipoprotein(a)

Background  High-quality methods for lipoprotein characterization are warranted in studies on various metabolic diseases.Materials and methods  An automated system for size-exclusion chromatography (SEC) of lipoproteins using commercially available components is described. Cholesterol or triglyceride content in separated lipoproteins from plasma and interstitial fluid (IF) was continuously determined on-line using microlitre sample volumes.Results  The lipoprotein assay showed a good concordance with the classic ultra-centrifugation/precipitation technique using fresh or frozen samples. Determination of lipoproteins in IF obtained from vacuum-induced skin blisters from 18 healthy subjects revealed that very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol levels were 18%, 19% and 25%, respectively, of concomitant plasma concentrations. The size-exclusion chromatography (SEC) system also allows for triglyceride determination on-line and it could be shown that the system is advantageous for an accurate determination of triglycerides in conditions when there are high levels of glycerol, e.g. in mice and in patients with hyperglycerolaemia (pseudo-hypertriglyceridaemia).Conclusions  The described system should be of value in studies where detailed lipoprotein analysis is warranted and particularly when significant sample series with small volumes are available. Our data also suggest that there is a 4–5·5-fold concentration gradient between plasma and IF for the three major plasma lipoproteins.

The effects of the administration of 50 mg of guggulipid or placebo capsules twice daily for 24 weeks were compared as adjuncts to a fruit- and vegetable-enriched prudent diet in the management of 61 patients with hypercholesterolemia (31 in the guggulipid group and 30 in the placebo group) in a randomized, double-blind fashion. Guggulipid decreased the total cholesterol level by 11.7%, the low density lipoprotein cholesterol (LDL) by 12.5%, triglycerides by 12.0%, and the total cholesterol/high density lipoprotein (HDL) cholesterol ratio by 11.1% from the postdiet levels, whereas the levels were unchanged in the placebo group. The HDL cholesterol level showed no changes in the two groups. The lipid peroxides, indicating oxidative stress, declined 33.3% in the guggulipid group without any decrease in the placebo group. The compliance of patients was greater than 96%. The combined effect of diet and guggulipid at 36 weeks was as great as the reported lipid-lowering effect of modern drugs. After a washout period of another 12 weeks, changes in blood lipoproteins were reversed in the guggulipid group without such changes in the placebo group. Side effects of guggulipid were headache, mild nausea, eructation, and hiccup in a few patients.

Summary  We used a new and remarkably simple method to examine the extent of in vivo lipoprotein glycation in type II diabetic patients with atherosclerosis and diabetic patients with no complications. Serum glycated lipoprotein levels were determined by agarose gel film electrophoresis in 48 non-diabetic control subjects and 39 diabetic patients, of whom 26 had no complications and 13 had atherosclerotic

Background: Risk of cardiovascular disease is assessed, in part, by laboratory measurement of the concentra- tions of several lipoproteins. b-Quantification is a method of lipoprotein measurement that uses ultracen- trifugation to partially separate lipoprotein classes. Al- though b-quantification is used largely in clinical and basic research, methods have not been described to allow the analysis of a large number of

This metabolic study was designed to investi- gate the effects of mycoprotein on blood lipids. Mycoprotcin is a food produced by continuous fermentation of Fusarium graminearum (Schwabe) on a carbohydrate substrate. Iwo groups of subjects with slightly raised cholesterol concentra- tions took part in the 3-wk study. The experimental group was fed mycoprotein in place of meat and the control

The goal of this study was to examine the association between paraoxonase-1 (PON1) activity and concentration and the severity and extent of coronary artery disease (CAD). Paraoxonase-1, a high-density lipoprotein-associated enzyme, is proposed to have an antiatherogenic effect by protecting low-density lipoproteins against oxidation. We studied PON1 activity and concentration in 107 patients with known or suspected CAD referred for cardiac catheterization. Based on visual estimation of coronary angiograms, subjects were classified as having no or mild CAD (<50% stenosis) and significant CAD (> or =50% stenosis). Quantitative coronary angiography (QCA) was used to estimate the indexes of severity, extent, and overall atheroma burden of CAD. We found lower values of PON1 activity and concentration (p = 0.003 and p = 0.016, respectively) in the group with significant CAD as compared with the group with no or mild CAD. The PON1 activity was significantly inversely correlated with CAD severity (r = -0.364, p < 0.001), extent (r = -0.221, p = 0.022), and atheroma burden (r = -0.277, p = 0.004). Similarly, PON1 concentration correlated with CAD severity (r = -0.306, p = 0.001) and atheroma burden (r = -0.229, p = 0.017). In multiple regression analysis, gender and PON1 activity were significant determinants of the severity of CAD independently of age, hypertension, smoking, abnormal glucose regulation, and high-density lipoprotein cholesterol. Our results indicate that PON1 activity and concentration are lower in subjects with significant CAD, and that there is a significant relationship between PON1 activity and concentration and CAD assessed by QCA.

Aronia melanocrpa fruit juice (AMFJ) used in our experiment was very rich in phenolic substances (709.3 mg gallic acid equivalents/100 ml juice). Anthocyanins (106.8 mg cyanidin-3-glucoside equivalents/100 ml juice) were the main flavonoid group. The aim of this study was to assess the influence of AMFJ on plasma lipids and lipoprotein profile, and histopathology of liver and aorta in rats with dietary-induced hyperlipidemia. AMFJ was administered by gavage for 30 days at doses of 5, 10 and 20 ml/kg body weight to rats fed a standard diet (SD) or a 4% cholesterol-containing diet (4% ChD). The 4% ChD caused a significant elevation of plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG). AMFJ did not significantly influence plasma lipids in rats fed the SD and significantly hindered the elevation of plasma TC, LDL-C and TG in rats fed the 4% ChD. High-density lipoprotein cholesterol (HDL-C) levels were not significantly influenced either by...

Macrophages isolated from a variety of organs in several animal species exhibit high affinity binding sites that recognize chemically modified proteins. One of these binding sites recognizes human plasma low density lipoprotein (LDL) in which the positive charges on the epsilon-amino groups of lysine have been removed or neutralized by chemical modification, thus giving the protein an enhanced negative charge. Effective treatments include reaction of LDL with organic acid anhydrides (acetylation or maleylation) and reaction with aldehydes, such as treatment with malondialdehyde. After the negatively-charged LDL binds to the surface receptor sites, it is rapidly internalized by the macrophages by endocytosis and hydrolyzed in lysosomes. The liberated cholesterol is reesterified in the cytoplasm, producing massive cholesteryl ester deposition. The binding site for negatively-charged LDL has been demonstrated so far only on macrophages and other scavenger cells. It is not expressed in cultured fibroblasts, smooth muscle cells, lymphocytes, or adrenal cells. In addition to its affinity for acetylated LDL and malondialdehyde-treated LDL, the macrophage site binds a variety of polyanions. It exhibits a particularly high affinity for certain sulfated polysaccharides (dextran sulfate and fucoidin), certain polynucleotides (polyinosinic acid and polyguanylic acid), polyvinyl sulfate, and maleylated albumin. It is possible that the site that binds negatively-charged LDL may be responsible for the massive accumulation of cholesteryl esters that occurs in vivo in macrophages and other scavenger cells in patients with high levels of circulating plasma LDL.

The aim of this study was to investigate the adhesive phenotype of the human intestinal isolate Bifidobacterium bifidum MIMBb75 to human colon carcinoma cell lines. We have previously shown that the adhesion of this strain to Caco-2 cells is mediated by an abundant surface lipoprotein named BopA. In this study, we found that this strain adheres to Caco-2 and HT-29 cells, and that its adhesion strongly depends on the environmental conditions, including the presence of sugars and bile salts and the pH. Considerably more adhesion to a Caco-2 monolayer occurred in the presence of fucose and mannose and less when MIMBb75 grew in Oxgall bile salts compared to standard environmental conditions. In particular, growth in Oxgall bile salts reduced the adhesion ability of MIMBb75 and modified the SDS-PAGE profile of the cell wall associated proteins of the strain. The pH markedly affected both adhesion to Caco-2 and bacterial autoaggregation. Finally, experiments with sodium metaperiodate suggested that not only proteinaceous determinants are involved in the adhesion process of B. bifidum. In conclusion, it seems that the colonization strategy of this bacterium can be influenced by factors varying along the gastrointestinal tract, such as the presence of specific sugars and bile salts and the pH, possibly limiting the adhesion of B. bifidum to only restricted distal sites of the gut.