Oxidized lipoproteins in blood plasma: possible marker of atherosclerosis progression

Oxidized lipoproteins and antioxidants were detected during the course of hypercholesterolemia development in cholesterol-fed rabbits. Lipid peroxides in blood plasma and very-low-, low-, and high-density lipoproteins (beta-VLDL, LDL, and HDL) were increased during the course of hypercholesterolemia. The content of phospholipid peroxides increased in beta-VLDL and LDL in parallel to that of cholesterol, whereas the amount of alpha-tocopherol was decreased either in lipoproteins or blood plasma. Ascorbate and urate concentrations were also decreased. Lipid peroxides were positively correlated with volume and area of atherosclerotic lesions, suggesting a relation between the concentrations of lipid peroxides in blood plasma and the progression of atheromatous lesions.     

APA hamster model for diabetic atherosclerosis. 2. Analysis of lipids and lipoproteins.

Syrian hamsters of the APA strain (APA hamsters) have recently been shown to have atheromatous lesions in the aortic arches under diabetic condition induced by a single injection of streptozotocin (SZ). In that model, fatty streaks, which are the initial lesions of atherogenesis, develop by 6 weeks after the injection (WAI). In this study, we evaluated plasma lipid concentrations and lipoprotein profiles in diabetic APA hamsters at 6 WAI to reveal the early stage of atherogenesis clinicopathologically. As a result, by biochemical analysis, hyperglycemic APA hamsters showed signs of hypercholesterolemia and hypertriglyceridemia. Low-density lipoprotein (LDL) cholesterol significantly increased, but high-density lipoprotein (HDL) cholesterol significantly decreased. Agarose gel electrophoresis showed an obvious increase in the fractions of chylomicron, LDL and abnormal lipoprotein. Plasma LDL in diabetic animals was in a state more susceptible to oxidization. In addition, a significant increase in glycated LDL was also found in the diabetic animals by enzyme linked immunosorbent assay (ELISA). Moreover, lipid peroxidation product (4-hydroxynonenal (4 HNE))-adducted proteins and advanced glycation end-products (AGE) were immunohistochemically detected in the foam cells of the fatty streaks. These results revealed that diabetic APA hamsters had hyperlipidemia characterized by increases in chylomicron, LDL and abnormal lipoprotein, and suggested that oxidized LDL and/or glycated LDL might be actively uptaken by macrophages and play an important role in the initial stage of atherogenesis.     

Thrombosis and atherosclerosis: regulatory role of interactions among blood components and endothelium

Complex interactions among constituents of blood and components of the vessel wall are involved in the pathogenesis of atherosclerosis and its subsequent thrombotic complications. Alterations in the endothelium are central both to the slowly progressive process of atherogenesis and to the acute events leading to thrombotic occlusion. Recent data, obtained by systematic evaluation of chronologic events that occur in diet-induced atherosclerosis, have extended our understanding of interactive processes among endothelium, monocytes, platelets, vascular smooth muscle cells, and humoral hemostatic elements in atherogenesis.     

Extraction of lipids and lipophilic antioxidants from fish tissues: a comparison among different methods.

1. Lipids, phospholipids and lipid soluble antioxidants were extracted from Sparus auratus liver and white muscle by three different methods and the yields obtained were compared. 2. None of the three procedures can recover the above components with the same efficiency. 3. For comparison the methods were also applied to rat liver homogenates. 4. The choice of the extraction procedures depends on the tissue investigated and on specific research requirements.     

Mussel glyoxalase I as a possible marker for ecotoxicological studies: Purification and preliminary characterization

Alpha-ketoaldehydes may be formed in cells during oxidative processes and glyoxalase I is the main enzyme involved in the detoxification pathway for these highly toxic compounds. Increased glyoxalase I activity has been observed in mussels exposed to high environmental levels of pollutants and a role for this enzyme as a protection mechanism against peroxidation damage has been hypothesized. In this paper, glyoxalase I from mussel tissue has been purified and a preliminary investigation of its molecular properties carried out. A two step purification procedure for glyoxalase I from digestive gland of Mytilus galloprovincialis is described. The pure enzyme is a 48 kDa protein with an heterodimeric quaternary structure composed of 24 and 25 kDa subunits. The isoelectric point of the native enzyme is at pH 5.0 and there is a divalent cation (probably Zn⁺⁺) requirement for activity. The series of alkyl-S-glutathiones, from methyl- to decyl-, are competitive inhibitors of glyoxalase I. Ki values exponentially decrease from 1.15 mM to 2.65 μM with increasing chain length. Mussel glyoxalase I exhibits molecular properties similar to those of the mammalian enzyme. The possible role of glyoxalase I in the detoxification of α-ketoaldehydes formed during oxidative stress is discussed.     

Randomised trial of lipid lowering dietary advice in general practice: the effects on serum lipids,lipoproteins, and antioxidants.

OBJECTIVE--To determine the relative efficacy in general practice of dietary advice given by a dietitian, a practice nurse, or a diet leaflet alone in reducing total and low density lipoprotein cholesterol concentration. DESIGN--Randomised six month parallel trial. SETTING--A general practice in Oxfordshire. SUBJECTS--2004 subjects aged 35-64 years were screened for hypercholesterolaemia; 163 men and 146 women with a repeat total cholesterol concentration of 6.0-8.5 mmol/l entered the trial. INTERVENTIONS--Individual advice provided by a dietitian using a diet history, a practice nurse using a structured food frequency questionnaire, or a detailed diet leaflet sent by post. All three groups were advised to limit the energy provided by fat to 30% or less and to increase carbohydrate and dietary fibre. MAIN OUTCOME MEASURES--Concentrations of total cholesterol and low density and high density lipoprotein cholesterol after six months; antioxidant concentration and body mass index. RESULTS--No significant differences were found at the end of the trial between groups in mean concentrations of lipids, lipoproteins, and antioxidants or body mass index. After data were pooled from the three groups, the mean total cholesterol concentration fell by 1.9% (0.13 mmol/l, 95% confidence interval 0.06 to 0.22, P < 0.001) to 7.00 mmol/l, and low density lipoprotein cholesterol also fell. The total carotenoid concentration increased by 53 nmol/l (95% confidence interval 3.0 to 103, P = 0.039). CONCLUSIONS--Dietary advice is equally effective when given by a dietitian, a practice nurse, or a diet leaflet alone but results in only a small reduction in total and low density lipoprotein cholesterol. To obtain a better response more intensive intervention than is normally available in primary care is probably necessary.     

Phenolic antioxidants: a rationale for design and evaluation of novel antioxidant drug for atherosclerosis

With increasing evidence that shows the involvement of active oxygen and nitrogen species in a variety of disorders, cancer, and aging, the role of antioxidant against oxidative stress has received renewed attention. In this review article, a rationale for design of lipophilic, radical-scavenging antioxidant is presented and the potency of a novel antioxidant, 2,3-dihydro-5-hydroxy-2,2-dipentyl-4, 6-di-tert-butylbenzofuran (BO-653), as an inhibitor of LDL oxidation was evaluated by considering various factors such as reactivity toward radicals, localization, and mobility in the lipoprotein, and fate of its radical. The anti-atherogenic activity of BO-653 was compared with those of alpha-tocopherol, probucol, and its metabolites. Furthermore, a novel function of phenolic antioxidants such as cell regulation and induction of phase II defense antioxidants are also discussed.     

GFP‐SCFV: Expression and possible applications as a tool for experimental investigations of atherosclerosis

Experimental studies on atherosclerosis are crucial for investigating its pathophysiology, defining new therapeutic targets, and developing new drugs and diagnostic tools. Thus, many imaging markers have been developed and introduced in experimental studies. The main advantage of these new tools is that they allow the noninvasive diagnosis of atherosclerotic vascular disease. Here, we describe the cloning, expression, purification, and stabilization of a chimeric protein specifically designed to probe cells and tissues for the presence of LDL(?), a relevant marker of atherosclerosis. The DNA sequence that encodes the anti‐LDL(?) scFv, previously obtained from a hybridoma secreting an anti‐LDL(?) monoclonal antibody, was inserted into the bacterial vector pET‐28a(+) in tandem with a DNA sequence encoding GFP. The recombinant protein was expressed in high yields in E. coli as inclusion bodies. The applicability of GFP‐scFv was assessed by ELISA, which determined its affinity for LDL(?) and confocal microscopy, that showed macrophage uptake of the protein along with LDL(?). In conclusion, our data suggest that the anti‐LDL(?) GFP‐scFv chimeric protein could be useful in studies on atherogenesis as well as for developing diagnostic tools for atherosclerosis. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1206–1213, 2014     

Manganese exposure among smelting workers: blood manganese–iron ratio as a novel tool for manganese exposure assessment

Unexposed control subjects (n = 106), power distributing and office workers (n = 122), and manganese (Mn)-exposed ferroalloy smelter workers (n = 95) were recruited to the control, low and high groups, respectively. Mn concentrations in saliva, plasma, erythrocytes, urine and hair were significantly higher in both exposure groups than in the controls. The Fe concentration in plasma and erythrocytes, however, was significantly lower in Mn-exposed workers than in controls. The airborne Mn levels were significantly associated with Mn/Fe ratio (MIR) of erythrocytes (eMIR) (r = 0.77, p < 0.01) and plasma (pMIR) (r = 0.70, p < 0.01). The results suggest that the MIR may serve as a useful biomarker to distinguish Mn-exposed workers from the unexposed, control population.     

Phosphorylation and dephosphorylation of membrane proteins as a possible mechanism for structural rearrangement of membrane components.

A correlation was found between dephosphorylation of chicken erythrocyte membrane proteins, aggregation of intramembrane particles, increase in the lipid bilayer phase of the membrane and exposure of membrane phospholipids toward phospholipase A and trinitrobenzene sulfonic acid. Most of the covalently bound phosphate of the membrane proteins turns over and is associated with 5 major bands. It is suggested that phosphorylation and dephosphorylation of these proteins causes changes in their charge and conformation. Such changes might affect the interaction of these proteins with the neighbouring lipids or lipoprotein complexes and results in the aggregation of intramembrane particles and relative increase in the exposed free lipid bilayer phase of the membrane.     

On the possible use of the serum level of 7 alpha-hydroxycholesterol as a marker for increased activity of the cholesterol 7 alpha-hydroxylase in humans

The possibility was investigated that the serum level of 7 alpha-hydroxycholesterol can be used as a marker for cholesterol 7 alpha-hydroxylase activity. Six patients with gallstone disease were found to have a mean level of 7 alpha-hydroxycholesterol in serum of 30 +/- 4 ng/ml (mean +/- SEM) as measured by isotope dilution-mass spectrometry, using deuterated 7 alpha-hydroxycholesterol as internal standard. After treatment with cholestyramine in a dose of 8 g twice daily for 2-3 weeks preoperatively, the serum level increased to 128 +/- 20 ng/ml (P less than 0.001). Eight other patients with gallstone disease had a mean level of 7 alpha-hydroxycholesterol in serum of 29 +/- 7 ng/ml. Treatment with chenodeoxycholic acid, 15 mg per kg body weight per day for 3-4 weeks before surgery, decreased the mean level to 20 +/- 7 ng/ml (P greater than 0.05). The activity of the cholesterol 7 alpha-hydroxylase in liver biopsies taken during operation was found to be 38 +/- 5 pmol/min per mg of protein in the group of patients treated with cholestyramine and 1.3 +/- 0.5 pmol/min per mg in the group of patients treated with chenodeoxycholic acid. Liver biopsies from a group of untreated patients (n = 13) had a mean cholesterol 7 alpha-hydroxylase activity of 7.6 +/- 1.5 pmol/min per mg.(ABSTRACT TRUNCATED AT 250 WORDS)     

The LWb blood group as a marker of prehistoric Baltic migrations and admixture.

Archaeological findings and historical records indicate frequent migrations and exchange of genetic material between populations in the Baltic Sea area. However, there have so far been very few attempts to trace migrations in this area using genetic markers. We have studied the Baltic populations with respect to exceptional variations in the frequencies of the Landsteiner-Wiener (LW) blood group. The frequency of the uncommon LWb gene was high in the Balts, around 6% among Latvians and Lithuanians, very low among the other western Europeans (0-0.1%) and apparently absent in Asiatic and African populations. From the Baltic region of peak frequency there was a regular decline of LWb incidence (a descending cline) in the neighboring populations: 4.0% in the Estonians, 2.9% in the Finns, 2. 2% in the Vologda Russians, and 2.0% in the Poles. Thus the distribution of LWb suggests considerable and extensive Baltic admixture, especially in the north and northeast direction. In Southern Sweden with an LWb frequency of 0.3%, the Baltic influence appeared slight, while in the population of the Swedish island Gotland in the middle of the Baltic Sea there was a significantly increased LWb frequency of 1.0% compared with that of Western European countries. The distinction of codominantly inherited LW antigenic forms, LWa and LWb (previously Nea), is known to be due to a single base substitution. Based on our population data, it is plausible that the expansion of this point mutation occurred only once during human history. Furthermore, our data indicate that the expansion of the LWb mutation occurred in Balts and that LWb can be considered a 'Baltic tribal marker', its presence in other populations being an indicator of the degree of Baltic genetic influence.     

Plasma lipids and lipoproteins and the prevalence of risk for coronary heart disease in Canadian adults. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To report population reference values for blood lipids, to determine the prevalence of lipid risk factors and to assess their association with other risk factors. DESIGN: Population-based cross-sectional surveys. Survey participants were interviewed at home and provided a blood sample at a clinic. All blood lipid analyses were done in the Lipid Research Laboratory, University of Toronto. The laboratory is standardized in the National Heart, Lung Blood Institute-Centres for Disease Control Standardization Program. SETTING: Nine Canadian provinces, from 1986 to 1990. PARTICIPANTS: A probability sample of 26,293 men and women aged 18 to 74 was selected from the health insurance registers for each province. Blood samples were obtained from 16,924 participants who had fasted 8 hours or more. OUTCOME MEASURES: Concentration of total plasma cholesterol, triglycerides and high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol in blood samples from fasting participants. MAIN RESULTS: Of the study population, 46% had total plasma cholesterol levels above 5.2 mmol/L, 15% had LDL-cholesterol levels above 4.1 mmol/L, 15% had triglyceride levels above 2.3 mmol/L and 8% had HDL-cholesterol levels below 0.9 mmol/L. Total plasma cholesterol, LDL-cholesterol and triglyceride levels rose with age in men to a maximum in the 45-54 age group; in women there was little change with age up to ages 45 to 54, at which time the level of each of these lipids increased appreciably. The age-standardized prevalence of obesity was positively associated with elevation of total plasma cholesterol. CONCLUSION: The results suggest the need for a multifactorial approach in health promotion efforts to lower blood cholesterol levels and reduce other risk factors in the population. A considerable number of adults were found to be at risk at all ages in both sexes. In the short term, men aged 34 and older and women aged 45 and older might benefit most from prevention programs.     

Standardizing cancer biomarkers criteria: data elements as a foundation for a database. Inflammatory mediator/M-CSF as model marker

The purpose of this position article was to design a set of criteria (data elements) for a wide range of cancer biomarkers (CBs) in an attempt to standardize biomarkers features through a common language as a foundation for a database. Data elements are described as a set of generic criteria, which should characterize nearly all biomarkers introduced in the literature. Data elements were extracted from the review of prominent features that biomarkers represent within various categories. The extracted characteristics of biomarkers produced a short list of shared and unique generic features such as biological nature and history; stage/phase of study; sensitivity and specificity; modes of action; risk assessment; validation status; technology, and recommendation status for diversified biomarkers. To tailor data elements on specific markers, a cytokine, such as macrophage-colony stimulating factor (M-CSF), which has been proposed as a ‹potentially suitable biomarker’ for diagnosis of ovarian, lung, breast, pancreatic, and colorectal cancers, was selected as a Model biomarker. Small scale clinical studies suggested the superior usefulness of M-CSF compared with traditional markers for cancer detection. A key criterion for selecting Model marker and tailoring data elements for detection of cancer was the comparison of data on its specificity and sensitivity with traditional markers. The design of data elements for standardizing CBs criteria is considered a Research Tool and a foundation for developing a comprehensive CBs database useful for oncology researchers for a wide range of biomarkers. Validation, integration and proper packaging, data visualization and recommendation of suitability of CBs, by a panel of experts, for technology development are important challenging next steps toward developing a reliable database, which would allow professionals to effectively retrieve and study integrated information on potentially useful markers; identify important knowledge gaps and limitations of data; and assess state of technologies and commercialization of markers at a point of need. Appropriate use of integrated information on biomarkers in clinical practices would eventually account for more cost-effective characteristics of an individual’s state of health.     

The nucleoside phosphatase method as a marker for the recognition of the autochthonous plexuses in blood vessel walls and the possible connection of the latter with acupuncture mechanisms.

The innervation of the blood vessels of the palatal mucosa of the frog is investigated histochemically. Besides vaso-motor nerves, fibers from the autochthonous plexuses also invest the vessels. Electron microscope studies of the latter show them to be non-nervous in structure contrary to previous belief. It is suggested they may influence vessels in a humoral manner and possibly play a part in acupuncture effector mechanisms. The electron micrographs are considered to reveal structure previously designated "terminal reticulum".     

Tocopherol-mediated peroxidation of lipoproteins: implications for vitamin E as a potential antiatherogenic supplement.

The 'oxidation theory' of atherosclerosis proposes that oxidation of low density lipoprotein (LDL) contributes to atherogenesis. Although little direct evidence for a causative role of 'oxidized LDL' in atherogenesis exists, several studies show that, in vitro, oxidized LDL exhibits potentially proatherogenic activities and lipoproteins isolated from atherosclerotic lesions are oxidized. As a consequence, the molecular mechanisms of LDL oxidation and the actions of alpha-tocopherol (alpha-TOH, vitamin E), the major lipid-soluble lipoprotein antioxidant, have been studied in detail. Based on the known antioxidant action of alpha-TOH and epidemiological evidence, vitamin E is generally considered to be beneficial in coronary artery disease. However, intervention studies overall show a null effect of vitamin E on atherosclerosis. This confounding outcome can be rationalized by the recently discovered diverse role for alpha-TOH in lipoprotein oxidation; that is, alpha-TOH displays neutral, anti-, or, indeed, pro-oxidant activity under various conditions. This review describes the latter, novel action of alpha-TOH, termed tocopherol-mediated peroxidation, and discusses the benefits of vitamin E supplementation alone or together with other antioxidants that work in concert with alpha-TOH in ameliorating lipoprotein lipid peroxidation in the artery wall and, hence, atherosclerosis.     

Short communication: Ascorbyl/ascorbate ratio as a marker of oxidative stress in larvae (Apis mellifera) exposed to Paenibacillus larvae

Paenibacillus larvae, the causal agent of American foulbrood disease (AFB), affects Apis mellifera larvae and can induce oxidative stress by overproduction of radical oxygen species (ROS). This study aimed to assess the oxidative stress levels in larvae exposed to three different strains of P. larvae through their diet by examining the ascorbyl radical (A) to ascorbate anion (AH¯) ratio. The results revealed that larvae inoculated with P. larvae exhibited a lower value of this index compared to uninoculated ones. Interestingly, the level of A remained constant, while the concentration of AH¯ increased. Said increase correlated with the virulence of the specific P. larvae strain used in the inoculation. These findings suggest a potential link between AH¯ molecules and a defense response in A. mellifera larvae against infection, consistent with their resistance to P. larvae (LD₅₀).