Evidence for a concerted reaction between lipid hydroperoxides and polypeptides

"Affimer" synthetic protein scaffolds block oxidized LDL binding to the LOX-1 scavenger receptor and inhibit ERK1/2 activation

In multicellular organisms, a variety of lipid-protein particles control the systemic flow of triacylglycerides, cholesterol, and fatty acids between cells in different tissues. The chemical modification by oxidation of these particles can trigger pathological responses, mediated by a group of membrane proteins termed scavenger receptors. The lectin-like oxidized low-density lipoprotein (LOX-1) scavenger receptor binds to oxidized low-density lipoprotein (oxLDL) and mediates both signaling and trafficking outcomes. Here, we identified five synthetic proteins termed Affimers from a phage display library, each capable of binding recombinant LOX-1 extracellular (oxLDL-binding) domain with high specificity. These Affimers, based on a phytocystatin scaffold with loop regions of variable sequence, were able to bind to the plasma membrane of HEK293T cells exclusively when human LOX-1 was expressed. Binding and uptake of fluorescently labeled oxLDL by the LOX-1-expressing cell model was inhibited with subnanomolar potency by all 5 Affimers. ERK1/2 activation, stimulated by oxLDL binding to LOX-1, was also significantly inhibited (p < 0.01) by preincubation with LOX-1-specific Affimers, but these Affimers had no direct agonistic effect. Molecular modeling indicated that the LOX-1-specific Affimers bound predominantly via their variable loop regions to the surface of the LOX-1 lectin-like domain that contains a distinctive arrangement of arginine residues previously implicated in oxLDL binding, involving interactions with both subunits of the native, stable scavenger receptor homodimer. These data provide a new class of synthetic tools to probe and potentially modulate the oxLDL/LOX-1 interaction that plays an important role in vascular disease.

Comparison of Enzyme Activity in Order to Describe the Metabolic Profile of Dairy Cows during Early Lactation

Enzymatic diagnostics have practical applications in diseases of the liver, heart, pancreas, muscles, blood, and neoplastic diseases. This study aimed to compare enzyme activity to describe dairy cows’ metabolism during early lactation. Based on their general health symptoms, the cows were assigned to one of three groups: acidotic, healthy and ketotic. Samples of milk, blood and rumen fluid were collected at 12 ± 5 days postpartum. Ketotic cows were characterized by the highest malondialdehyde (MDA, 76.098 nM/mL), glutathione reductase (GluRed, 109.852 U/L), superoxide dismutase (SOD, 294.22 U/L) and gamma-glutamyltranspeptidase (GGTP, 71.175 U/L) activity. In comparing ketotic and acidotic cows, MDA, GluRed, SOD and GGTP activity were higher by a factor of almost: 1.85, 1.89, 0.79 and 2.50, respectively. Acidotic cows were characterized by the highest aspartate aminotransferase activity (AspAT, 125.914 U/L). In comparing acidotic and ketotic cows, AspAT activity was higher by a factor of almost 1.90. The use of enzymatic markers could limit the frequency of sampling for laboratory analyses and may result in a faster diagnosis of metabolic disorders. AspAT activity in blood serum seems to be a good indicator of acidosis; GGTP may participate in the pathogenesis of ketosis.

Preparation of LDL , Oxidation , Methods of Detection, and Applications in Atherosclerosis Research

The concept of lipid peroxidation has been known for a long time. It is now well established that LDL plays a major role in atherosclerosis. Oxidized low-density lipoprotein (Ox-LDL) has been studied for over 35 years. Numerous pro- and anti-atherogenic properties have been attributed to Ox-LDL. Component composition of Ox-LDL is complex due to the influence of various factors, including the source, method of preparation, storage and use. Hence, it is very difficult to clearly define and characterize Ox-LDL. It contains unoxidized and oxidized fatty acid derivatives both in the ester and free forms, their decomposition products, cholesterol and its oxidized products, proteins with oxidized amino acids and cross-links, polypeptides with varying extents of covalent modification with lipid oxidation products and many others. The measurement of lipid oxidation has been a great boon, not only to the understanding of the process but also in providing numerous serendipitous discoveries and methodologies. In this chapter, we outline the methodologies for the preparation and testing of various lipoproteins for oxidation studies.

Intake of Alpha-Linolenic Acid-Rich Perilla frutescens Leaf Powder Decreases Home Blood Pressure and Serum Oxidized Low-Density Lipoprotein in Japanese Adults

Oxidized low-density lipoprotein (Ox-LDL) is known to be highly atherogenic. Thus, decreasing the blood levels of Ox-LDL through dietary means is an important approach to reduce cardiovascular events in high-risk individuals. In this randomized placebo-controlled human interventional trial, we aimed to evaluate whether Perilla frutescens leaf powder (PLP) ameliorates Ox-LDL and home blood pressure, along with its biological antioxidant potential. Healthy Japanese volunteers aged 30-60 years (n = 60) were randomized to PLP and placebo groups. The PLP group consumed PLP dried using a microwave under reduced pressure, and the placebo group consumed pectin fiber daily for 6 months. Home blood pressure, serum biochemical parameters, and fatty acid profiles of erythrocyte plasma membranes were analyzed. Plasma Ox-LDL levels significantly decreased in the PLP group but not in the placebo group. Mean changes in the biological antioxidant potential and alpha-linolenic acid levels in the erythrocyte plasma membrane were significantly increased in the PLP group than in the placebo group. In subjects with prehypertension (systolic blood pressure [SBP] ³ 120 mmHg), the mean reduction in morning or nocturnal SBP was significantly greater in the PLP group than in the placebo group. Thus, PLP intake may be an effective intervention to prevent cardiovascular diseases.

Fatty acid nitration in human low-density lipoprotein

Lipid nitration occurs during physiological and pathophysiological conditions, generating a variety of biomolecules capable to modulate inflammatory cell responses. Low-density lipoprotein (LDL) oxidation has been extensively related to atherosclerotic lesion development while oxidative modifications confer the particle pro-atherogenic features. Herein, we reviewed the oxidation versus nitration of human LDL protein and lipid fractions. We propose that unsaturated fatty acids present in LDL can be nitrated under mild nitration conditions, suggesting an anti-atherogenic role for LDL carrying nitro-fatty acids (NFA).

A Novel Mechanism for Atherosclerotic Calcification: Potential Resolution of the Oxidation Paradox

AIM

In this study, we tested the hypothesis that lipid peroxide-derived dicarboxylic acids (DCAs), by virtue of their ability to bind to calcium (Ca), might be involved in atherosclerotic calcification. We determined the ability of azelaic acid (AzA) to promote calcification in human aortic smooth muscle cells (HASMCs), identified AzA in human calcified atherosclerotic lesions, and compared its levels with control and noncalcified atherosclerotic lesions.

RESULTS

HASMCs efficiently converted 9-oxononanoic acid (ONA), a lipid peroxide-derived monocarboxylic aldehyde, to AzA. In vitro incubations of AzA micelles with HASMC resulted in the formation of Ca deposits, which contained AzA. Liquid chromatography-mass spectrometry analysis of human control uninvolved artery, noncalcified, and calcified lesions showed significant increase of AzA in calcified lesions compared with noncalcified and control tissues. Calcified mouse atherosclerotic lesions also showed substantial presence of AzA in Ca complexes.

INNOVATION

This study identifies a DCA, AzA, as an integral part of the Ca complex. The study also demonstrates the conversion of a lipid peroxidation product, ONA, as a potential source of AzA, and establishes the presence of AzA in calcified materials isolated from human and mouse lesions.

CONCLUSION

The presence of AzA as a Ca sequestering agent in atherosclerotic lesions (i) might indicate participation of oxidized low-density lipoprotein (Ox-LDL) derived products in calcification, (ii) explain the potential correlation between calcification and overall plaque burden (as Ox-LDL has been suggested to be involved in atherogenesis), (iii) could contribute to plaque stabilization via its anti-inflammatory actions, and (iv) might explain why antioxidants failed to affect atherosclerosis in clinical studies. Antioxid. Redox Signal. 29, 471-483.

Antioxidative activity of high-density lipoprotein (HDL): Mechanistic insights into potential clinical benefit

Uptake of low-density lipoprotein (LDL) particles by macrophages represents a key step in the development of atherosclerotic plaques, leading to the foam cell formation. Chemical modification of LDL is however necessary to induce this process. Proatherogenic LDL modifications include aggregation, enzymatic digestion and oxidation. LDL oxidation by one-electron (free radicals) and two-electron oxidants dramatically increases LDL affinity to macrophage scavenger receptors, leading to rapid LDL uptake and fatty streak formation. Circulating high-density lipoprotein (HDL) particles, primarily small, dense, protein-rich HDL3, provide potent protection of LDL from oxidative damage by free radicals, resulting in the inhibition of the generation of pro-inflammatory oxidized lipids. HDL-mediated inactivation of lipid hydroperoxides involves their initial transfer from LDL to HDL and subsequent reduction to inactive hydroxides by redox-active Met residues of apolipoprotein A-I. Several HDL-associated enzymes are present at elevated concentrations in HDL3 relative to large, light HDL2 and can be involved in the inactivation of short-chain oxidized phospholipids. Therefore, HDL represents a multimolecular complex capable of acquiring and inactivating proatherogenic lipids. Antioxidative function of HDL can be impaired in several metabolic and inflammatory diseases. Structural and compositional anomalies in the HDL proteome and lipidome underlie such functional deficiency. Concomitant normalization of the metabolism, circulating levels, composition and biological activities of HDL particles, primarily those of small, dense HDL3, can constitute future therapeutic target.

Pandora's Box: mitochondrial defects in ischaemic heart disease and stroke

Ischaemic heart disease and stroke are vascular events with serious health consequences worldwide. Recent genetic and epigenetic techniques have revealed many genetic determinants of these vascular events and simplified the approaches to research focused on ischaemic heart disease and stroke. The pathogenetic mechanisms of ischaemic heart disease and stroke are complex, with mitochondrial involvement (partially or entirely) recently gaining substantial support. Not only can mitochondrial reactive oxygen species give rise to ischaemic heart disease and stroke by production of oxidised low-density lipoprotein and induction of apoptosis, but the impact on pericytes contributes directly to the pathogenesis. Over the past two decades, publications implicate the causative role of nuclear genes in the development of ischaemic heart disease and stroke, in contrast to the potential role of mitochondrial DNA (mtDNA) in the pathophysiology of the disorders, which is much less understood, although recent studies do demonstrate that the involvement of mitochondria and mtDNA in the development of ischaemic heart disease and stroke is likely to be larger than originally thought, with the novel discovery of links among mitochondria, mtDNA and vascular events. Here we explore the molecular events and mtDNA alterations in relation to the role of mitochondria in ischaemic heart disease and stroke.

Cationic peptides neutralize Ox-LDL, prevent its uptake by macrophages, and attenuate inflammatory response

OBJECTIVE

Apolipoprotein A1 (ApoA1) and apolipoprotein E (ApoE) mimetic peptides have attracted attention due to their ability to reduce atherosclerosis and exhibit antioxidant, anti-inflammatory, and hypolipidemic properties. In this study, we tested whether three distinct and unrelated cationic peptides would inhibit the oxidation of lipoproteins and whether they would counteract and neutralize the negatively charged modified lipoproteins, inhibit their uptake and inflammation by macrophages.

METHODS AND RESULTS

5F-mimetic peptide of ApoA1, LL27 derived from the anti-microbial peptide hCAP, and a human glycodelin derived peptide were commercially synthesized. We noted that these three distinct cationic lysine-rich peptides, two of which were unrelated to any known apolipoproteins, inhibited copper-mediated oxidation of lipoproteins and reduced lipid peroxides in a lysine dependent manner. The peptides also retarded the electrophoretic mobility of previously oxidized LDL and acetylated LDL by virtue of their net positive charge. Pre-incubation of peptides with modified lipoproteins reduced the uptake of the latter by macrophages, thus preventing the formation of foam cells. The cationic peptides inhibited oxidized LDL (Ox-LDL)-induced inflammatory response both in vitro and in vivo.

CONCLUSION

Based on these results, we suggest that in addition to the well known mimetic peptides, other suitable cationic peptides may be of use for controlling Ox-LDL mediated inflammation and atherosclerotic progression.

Hexanoyl-lysine as an oxidative-injured marker - application of development of functional food

We could proposed that N(ε)-(hexanoy)lysine, HEL, become a useful biomarker for detection of oxidative stress damage occurred by exhaustive exercise. We examined the preventive effect of flavonoid compound, eriocitrin, against exercise-induced oxidative damage in rat liver. Eriocitrin administration prior to exercise significantly suppressed the increases in thiobarbituric acid-reactive substance caused by lipid peroxidation during exhaustive exercise. The increase in the contents of HEL in rat liver was also abolished by eriocitrin administration. The concentration of oxidized glutathione was significantly increased by exercise, but the eriocitrin administration suppressed this increase. These results suggested that eriocitrin administration prior to exercise prevented oxidative damages caused by exhaustive exercise-induced oxidative stress. Therefore, it was suggested that HEL could be a good biomarker for oxidative stress, especially at earlier stage when oxidative damage was occurred by lipid peroxidation than a stage of harmful aldehyde formation. Moreover, it was suggested that eriocitrin metabolites, eriodictyol and 3, 4 - dihydroxyhydrocinnamic, might scavenge free radicals and reactive oxygen species, resulting in suppression of lipid peroxidation and reactive proteins with radicals to form HEL. These findings implied that eriocitrin might be useful as an anti-oxidative compound to protect oxidative stress damages.

Urinary oxidative stress markers in children with autism

Oxidative stress caused by increased production of free radicals and impaired functions of antioxidants remains as the major factor associated with the pathophysiology of many neuropsychiatric diseases.

OBJECTIVE

The objective of the present study was to analyze the oxidative stress markers in urine sample since the collection of blood from these children is highly meticulous and also to evaluate whether these urinary markers can be correlated with the severity of autism.

METHODS

The subjects of the study were 45 autistic children with different grades of severity (low functioning autism (LFA), medium functioning autism (MFA), and high functioning autism (HFA) according to Childhood Autism Rating Scale (CARS), n=15 children in each group and 50 healthy children (age and sex matched). The boys and girls ratio involved in this study was 4:1, and they were of age 4-12 years. We determined the urinary levels of oxidative stress markers like thiobarbituric acid-reacting substances, lipid hydroperoxides, 4-hydroxy nonenal, protein carbonyls, sulfhydryl groups, total antioxidant capacity, total peroxide content, oxidative stress index, and also UA/Cr ratio in autistic children.

RESULTS

The study observed a significant elevation in the level of oxidative stress markers in autistic children when compared with normal children. The level of antioxidants excreted in urine was found to be significantly low in autistic children. These findings when correlated with the degrees of severity, oxidative stress markers showed positive correlation with increasing order of severity (LFA>MFA>HFA), whereas antioxidants showed negative correlation.

DISCUSSION

The study reveals that the urinary levels of oxidative stress markers can be considered as the measure of oxidative stress index in autistic children. The significant correlation between the severity of autism with urinary lipid peroxidation products also support the use of oxidative stress markers and antioxidants as biomarkers of autism.

Label-free separation of human embryonic stem cells and their differentiating progenies by phasor fluorescence lifetime microscopy

We develop a label-free optical technique to image and discriminate undifferentiated human embryonic stem cells (hESCs) from their differentiating progenies in vitro. Using intrinsic cellular fluorophores, we perform fluorescence lifetime microscopy (FLIM) and phasor analysis to obtain hESC metabolic signatures. We identify two optical biomarkers to define the differentiation status of hESCs: Nicotinamide adenine dinucleotide (NADH) and lipid droplet-associated granules (LDAGs). These granules have a unique lifetime signature and could be formed by the interaction of reactive oxygen species and unsaturated metabolic precursor that are known to be abundant in hESC. Changes in the relative concentrations of these two intrinsic biomarkers allow for the discrimination of undifferentiated hESCs from differentiating hESCs. During early hESC differentiation we show that NADH concentrations increase, while the concentration of LDAGs decrease. These results are in agreement with a decrease in oxidative phosphorylation rate. Single-cell phasor FLIM signatures reveal an increased heterogeneity in the metabolic states of differentiating H9 and H1 hESC colonies. This technique is a promising noninvasive tool to monitor hESC metabolism during differentiation, which can have applications in high throughput analysis, drug screening, functional metabolomics and induced pluripotent stem cell generation.

ω-6 lipids regulate PPAR turnover via reciprocal switch between PGC-1 alpha and ubiquitination

OBJECTIVE

Dietary ω-6 lipids such as linoleic acid and its oxidized forms (13-HPODE OxLA) interact with peroxisome proliferator-activated receptors (PPARs) and elicit pro and anti-atherogenic effects in vascular cells. Ligand-dependent PPAR protein turnover is promoted by ubiquitination, but attenuated by binding to its co-activator, peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1α). The objective of our study was to investigate if the dual atherogenic effects of ω-6 lipids are due to its regulation of PPAR turnover.

METHODS AND RESULTS

In rat aortic smooth muscle cells (RASMCs), oxidized linoleic acid (OxLA) at 10-50 μM induced and stabilized PPARα protein at earlier time points (0-4 h) but suppressed it at 12 h. Conversely, it activated PPARγ protein turnover at a later time point (12 h). Pre-treatment with the proteasome inhibitor (MG132) prevented OxLA mediated loss of PPAR stability and transactivity. Co-immunoprecipitation studies indicated a ligand mediated time-dependent reciprocal exchange of PPAR interaction between ubiquitination and PGC-1α. This ω-6 lipid mediated time-dependent switch between PPAR degradation versus stability helped modulate the pro and anti-atherogenic effects of these dietary lipids.

CONCLUSION

Our findings provide insights into the dual pro and anti-atherogenic effects of dietary ω-6 lipids on vascular cells by the regulation of PPAR turnover.

Fluorescent adducts formed by reaction of oxidized unsaturated fatty acids with amines increase macrophage viability

Macrophages are prominent components of human atherosclerotic lesions and they are believed to accelerate the progression and/or complications of both early and advanced atherosclerotic lesions. We and others have shown that oxidized low-density lipoprotein (oxLDL) induces growth and inhibits apoptosis in murine bone marrow-derived macrophages. In this study, we sought to characterize the oxidative modification of LDL that is responsible for this prosurvival effect. We found that both the modified lipid and the modified protein components of oxLDL can increase the viability of macrophages. The key modification appeared to involve derivatization of amino groups in apoB or in phosphatidylethanolamine by lipid peroxidation products. These reactive oxidation products were primarily unfragmented hydroperoxide- or endoperoxide-containing oxidation products of linoleic acid or arachidonic acid. LC-MS/MS studies showed that some of the arachidonic acid-derived lysine adducts were isolevuglandins that contain lactam and hydroxylactam rings. MS/MS analysis of linoleic acid autoxidation adducts was consistent with 5- or 6-membered nitrogen-containing heterocycles derived from unfragmented oxidation products. The amine modification by oxidation products generated a fluorescence pattern with an excitation maximum at 350nm and emission maximum at 430nm. This is very similar to the fluorescence spectrum of copper-oxidized LDL.

Atherogenic ω-6 Lipids Modulate PPAR- EGR-1 Crosstalk in Vascular Cells

Atherogenic ω-6 lipids are physiological ligands of peroxisome proliferator-activated receptors (PPARs) and elicit pro- and antiatherogenic responses in vascular cells. The objective of this study was to investigate if ω-6 lipids modulated the early growth response-1 (Egr-1)/PPAR crosstalk thereby altering vascular function. Rat aortic smooth muscle cells (RASMCs) were exposed to ω-6 lipids, linoleic acid (LA), or its oxidized form, 13-HPODE (OxLA) in the presence or absence of a PPARα antagonist (MK886) or PPARγ antagonist (GW9662) or PPAR-specific siRNA. Our results demonstrate that ω-6 lipids, induced Egr-1 and monocyte chemotactic protein-1 (MCP-1) mRNA and protein levels at the acute phase (1-4 hrs) when PPARα was downregulated and at subacute phase (4-12 hrs) by modulating PPARγ, thus resulting in altered monocyte adhesion to RASMCs. We provide novel insights into the mechanism of action of ω-6 lipids on Egr-1/PPAR interactions in vascular cells and their potential in altering vascular function.

Role of superoxide radical anion in the mechanism of apoB100 degradation induced by DHA in hepatic cells

VLDL is produced by the liver. Its major protein is apoB100. Docosahexaenoic acid (DHA), a dietary polyunsaturated fatty acid (PUFA), reduces VLDL levels and is used therapeutically for hypertriglyceridemia. In model systems, DHA lowers VLDL secretion by inducing presecretory apoB100 degradation, a process dependent on PUFA-derived lipid peroxides. We hypothesized that superoxide (SO) was a major participant in DHA-induced apoB100 degradation, given its promotion of lipid peroxidation. SO levels in a model of VLDL metabolism, rat hepatoma McArdle cells, were either decreased by a mimetic of superoxide dismutase 1 (SOD1) or by overexpressing SOD1 or increased by SOD1 siRNA. ApoB100 recovery was assessed by immunoprecipitation, SO by 2-hydroxyethidine, and lipid peroxides by thiobarbituric acid reactive substances. The SOD1 mimetic or SOD1 overexpression reduced SO and inhibited apoB100 degradation in DHA-treated cells by up to 100%. Surprisingly, silencing SOD1 did not increase DHA-induced degradation, although levels of SO were higher (+44%); those of lipid peroxides were similar, and their reduction by α-tocopherol decreased degradation by 50%. SO is required for lipid peroxidation in DHA-induced apoB100 degradation, but it is the peroxide level that has a tighter relationship to the level of degradation and the regulation of VLDL production.

Oxidized low-density lipoprotein

Oxidized low-density lipoprotein (Ox-LDL) has been studied for over 25 years. Numerous pro- and anti-atherogenic properties have been attributed to Ox-LDL. Yet, Ox-LDL has neither been defined nor characterized, as its components and composition change depending on its source, method of preparation, storage, and use. It contains unoxidized and oxidized fatty acid derivatives both in the ester and free forms, their decomposition products, cholesterol and its oxidized products, proteins with oxidized amino acids and cross-links, and polypeptides with varying extents of covalent modification with lipid oxidation products, and many others. It seems to exist in vivo in some form not yet fully characterized. Until its pathophysiological significance, and how it is generated in vivo are determined, the nature of its true identity will be only of classical interest. In this review, its components, their biological actions and methods of preparation will be discussed.

Cholesterol oxides inhibit cholesterol esterification by lecithin: cholesterol acyl transferase

Cholesterol oxides are atherogenic and can affect the activity of diverse important enzymes for the lipidic metabolism. The effect of 7β-hydroxycholesterol, 7-ketocholesterol, 25-hydroxycholesterol, cholestan-3β,5α,6β-triol,5,6β-epoxycholesterol, 5,6α-epoxycholesterol and 7α-hydroxycholesterol on esterification of cholesterol by lecithin:cholesterol acyl transferase (LCAT, EC 2.3.1.43) and the transfer of esters of cholesterol oxides from high density lipoprotein (HDL) to low density lipoproteins (LDL) and very low density lipoproteins (VLDL) by cholesteryl ester transfer protein (CETP) was investigated. HDL enriched with increasing concentrations of cholesterol oxides was incubated with fresh plasma as source of LCAT. Cholesterol and cholesterol oxides esterification was followed by measuring the consumption of respective free sterol and oxysterols. Measurements of cholesterol and cholesterol oxides were done by gas-chromatography. 14C-cholesterol oxides were incorporated into HDL2 and HDL3 subfractions and then incubated with fresh plasma containing LCAT and CETP. The transfer of cholesterol oxide esters was followed by measuring the 14C-cholesterol oxide-derived esters transferred to LDL and VLDL. All the cholesterol oxides studied were esterified by LCAT after incorporation into HDL particles, competing with cholesterol by LCAT. Cholesterol esterification by LCAT was inversely related to the cholesterol oxide concentration. The esterification of 14C-cholesterol oxides was higher in HDL3 and the transfer of the derived esters was greater from HDL2 to LDL and VLDL. The results suggest that cholesterol esterification by LCAT is inhibited in cholesterol oxide-enriched HDL particles. Moreover, the cholesterol oxides-derived esters are efficiently transferred to LDL and VLDL. Therefore, we suggest that cholesterol oxides may exert part of their atherogenic effect by inhibiting cholesterol esterification on the HDL surface and thereby disturbing reverse cholesterol transport.

Red-wine Beneficial Long-term Effect on Lipids but not on Antioxidant Characteristics in Plasma in a Study Comparing Three Types of Wine--Description of twoO-methylated Derivatives of Gallic Acid in Humans

The purpose of this double clinical study was (1) to evaluate the effect of one single intake (300 ml) of red wine (RW) on the plasma antioxidant capacity (pAOC) and plasma phenolics over the 24-h time period following the intake, and (2) to compare the long-term effects of daily intakes (250 ml/d) of RW, white wine (WW) and Champagne (CH) on the plasma and LDL characteristics of healthy subjects. In the first part, blood samples were collected just before and after wine consumption. In the second part, subjects received the 3 types of wine successively, only at the mealtime, over 3-week periods separated by a 3-week wash out. Blood samples were drawn in fasting condition before and after each 3-week wine consumption period. The peak of pAOC was at 3-4 h following the single intake of RW, that of catechin was at 4 h (0.13 micromol/l) and that of gallic acid and caffeic acid was earlier (< or = 1.5 and 0.3 micromol/l, respectively). In plasma, the major form of gallic acid was 4-O-methylated, but a minor form (the 3-O-methyl derivative) appeared. In the long term study, no wine was able to change LDL oxidizability, but some other parameters were modified specifically: RW decreased pAOC (without changing TBARS and uric acid plasma levels), LDL lipids and total cholesterol (TC), and increased plasma apoA1, whereas CH increased plasma vitamin A. The beneficial effect of RW seems to mainly be explained by its action on lipid and lipoprotein constants, and not by its antioxidant one.

Alpha-tocopherol is ineffective in preventing the decomposition of preformed lipid peroxides and may promote the accumulation of toxic aldehydes: a potential explanation for the failure of antioxidants to affect human atherosclerosis

The decomposition of peroxidized lipids of low-density lipoprotein (LDL) has been suggested to be involved in atherosclerosis. In this study, an in vitro system with 13-hydroperoxylinoleic acid (13-HPODE) was used to determine the effects of antioxidants on its decomposition. Decomposition of 13-HPODE was not affected by alpha-tocopherol, several other antioxidants, or antioxidant enzymes. Moreover, the inclusion of alpha-tocopherol during the decomposition of 13-HPODE resulted in an accumulation of aldehydes. Further oxidation of aldehydes to carboxylic acids by a number of oxidases was prevented by alpha-tocopherol. Conversely, the formation of carboxylic acids may be conducive to plaque stabilization via immunomodulation, rapid degradation, and by calcium sequestration. Thus, the inhibition of formation of carboxylic acids could be a serious deleterious effect of antioxidant treatment. In contrast, alpha-keto acids, like pyruvic acid, promoted the conversion of 13-HPODE to 13-hydroxylinoleic acid (13-HODE) by readily undergoing decarboxylation into acetate. These observations suggest that agents that promote the reduction of lipid peroxides into lipid hydroxides could be far more effective in treating cardiovascular diseases as opposed alpha-tocopherol-like antioxidants that could affect additional steps in the oxidation cascade.

Peroxynitrite-mediated lipid oxidation and nitration: mechanisms and consequences

Lipid oxidation and nitration represents a novel area of research of relevance in the understanding of inflammatory processes. Peroxynitrite, the product of the diffusion-limited reaction between nitric oxide and superoxide anion, mediates oxidative modifications in lipid systems including cell membranes and lipoproteins. In this review, we discuss the mechanisms of lipid oxidation and nitration by peroxynitrite as well as the influence of physiological molecules and cell targets to redirect peroxynitrite reactivity. We also provide evidence to support that oxidation/nitration of lipids results in the formation of novel signaling modulators of key lipid-metabolizing enzymes.

Lipid peroxidation of membrane phospholipids generates hydroxy-alkenals and oxidized phospholipids active in physiological and/or pathological conditions

Polyunsaturated fatty acids (PUFAs) and their metabolites have a variety of physiological roles including: energy provision, membrane structure, cell signaling and regulation of gene expression. Lipids containing polyunsaturated fatty acids are susceptible to free radical-initiated oxidation and can participate in chain reactions that increase damage to biomolecules. Lipid peroxidation, which leads to lipid hydroperoxide formation often, occurs in response to oxidative stress. Hydroperoxides are usually reduced to their corresponding alcohols by glutathione peroxidases. However, these enzymes are decreased in certain diseases resulting in a temporary increase of lipid hydroperoxides that favors their degradation into several compounds, including hydroxy-alkenals. The best known of these are: 4-hydroxy-2-nonenal (4-HNE) and 4-hydroxy-2-hexenal (4-HHE), which derive from lipid peroxidation of n-6 and n-3 fatty acids, respectively. Compared to free radicals, these aldehydes are relatively stable and can diffuse within or even escape from the cell and attack targets far from the site of the original event. These aldehydes exhibit great reactivity with biomolecules, such as proteins, DNA, and phospholipids, generating a variety of intra and intermolecular covalent adducts. At the membrane level, proteins and amino lipids can be covalently modified by lipid peroxidation products (hydoxy-alkenals). These aldehydes can also act as bioactive molecules in physiological and/or pathological conditions. In addition this review is intended to provide an appropriate synopsis of identified effects of hydroxy-alkenals and oxidized phospholipids on cell signaling, from their intracellular production, to their action as intracellular messenger, up to their influence on transcription factors and gene expression.

Comparative in vitro toxicity of grape- and citrus-farm dusts

Agricultural workers are exposed to a variety of airborne dusts, including crystalline silica and other inorganic minerals. This study was designed to characterize the organic and inorganic components of agricultural dusts in California grape- and citrus-farm fields and to compare their cytotoxicity using in vitro toxicity bioassays as predictors of pathogenicity. Aerosolized dusts collected from farm fields were characterized by scanning-electron-microscopic energy-dispersive x-ray analysis, x-ray diffraction, trace metal analysis by plasma emission spectroscopy, and surface area measurements. As indicators of cytotoxicity, cell viability, release of alveolar enzymes activities (lactate dehydrogenase, N-acetyl glucosaminidase), production of reactive oxygen species (ROS), such as H2O2 and hydroxyl radical (OH), and lipid peroxidation were monitored after exposure of cells to grape- and citrus-farm dusts or inorganic components of these dusts. In addition, activation of nuclear factor kappa B and activator protein-1 were evaluated at the peak time for response of 36 h postexposure. All toxicity studies were done in comparison with crystalline silica of similar particle size and diameter using the same mass concentrations as farm dusts. The results showed that inorganic minerals in the aerosolized farm dust fractions were mostly composed of aluminum silicates, crystalline silica, and free iron. Crystalline silica used in these studies was more cytotoxic than grape- and citrus-farm dusts. However, in general, citrus farm dust exhibited the greatest ability to generate ROS and induce lipid peroxidation. These results support human epidemiologic studies, reporting an increased incidence of pulmonary fibrosis in farm workers, by documenting the potential of farm dusts to induce oxidative stress and initiate disease development.

Lipid nitration and formation of lipid-protein adducts: biological insights

Lipid-protein adducts are formed during oxidative and nitrative stress conditions associated with increasing lipid and protein oxidation and nitration. The focus of this review is the analysis of interactions between oxidative-modified lipids and proteins and how lipid nitration can modulate lipid-protein adducts formation. For this, two biologically-relevant models will be analysed: a) human low density lipoprotein, whose oxidation is involved in the early steps of atherogenesis, and b) alpha-synuclein/lipid membranes system, where lipid-protein adducts are being associated with the develop of Parkinson disease and other synucleinopathies.

Lipid-Derived Modifications of Plasma Proteins in Experimental and Human Diabetes

Plasma from two diabetic rat models and human diabetic patients was analyzed to investigate the hypothesis that enhanced oxidative stress in diabetes promotes lipid-derived protein modification. We evaluated the nonenzymatic modification of plasma protein by oxidized phospholipids, including measurement of protein-bound pentanedioate, nonanedioate, and hexanoate, all derived from oxidation of phospholipid polyunsaturated fatty acids. Generally pentanedioate was higher in diabetic compared with nondiabetic control groups, and nonanedioate was also higher in the diabetic rat models. We conclude that diabetes is associated with higher levels of phospholipid-derived protein modification in both animal models and human diabetes. Their role in the development of diabetes vascular complications warrants further research.

Identification of linoleic acid free radicals and other breakdown products using spin trapping with liquid chromatography-electrospray tandem mass spectrometry

Linoleic acid radical products formed by radical reaction (Fenton conditions) were trapped using 5,5-dimethyl-1-pyrrolidine-N-oxide (DMPO) and analysed by reversed-phase liquid chromatography coupled to electrospray mass spectrometry (LC-MS). The linoleic acid radical species detected as DMPO spin adducts comprised oxidized linoleic acid and short-chain radical species that resulted from the breakdown of carbon and oxygen centred radicals. Based on the m/z values, the short-chain products were identified as alkyl and carboxylic acid DMPO radical adducts that exhibited different elution times. The ions identified as DMPO radical adducts were studied by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS spectra of linoleic acid DMPO radical adducts exhibited the fragment ion at m/z 114 and/or the loss of neutral molecule of 113 Da (DMPO) or 131 Da (DMPO + H2O), indicated to be DMPO adducts. The short-chain products identified allowed inference of the radical oxidation along the linoleic acid chain by abstraction of hydrogen atoms in carbon atoms ranging from C-8 to C-14. Other ions containing the fragment ion at m/z 114 in the LC-MS/MS spectra were attributed to DMPO adducts of unsaturated aldehydes, hydroxy-aldehydes and oxocarboxylic acids. The identification of aldehydic products formed by radical oxidation of linoleic acid peroxidation products, as short-chain product DMPO adducts, is a means of identifying lipid peroxidation products.

Formation of N-(hexanoyl)ethanolamine, a novel phosphatidylethanolamine adduct, during the oxidation of erythrocyte membrane and low-density lipoprotein

The primary amino groups of biomolecules such as aminophospholipids, as well as proteins, are the potential targets of covalent modifications by lipid peroxidation products; however, little attention has been paid to the modification of aminophospholipids such as phosphatidylethanolamine (PE). The purpose of this study is to characterize the formation of a novel modified phospholipid, N-(hexanoyl)phosphatidylethanolamine (HEPE), in the reaction of PE with lipid hydroperoxides using mass spectrometric analyses. Upon reaction of egg PE with 13-hydroperoxyoctadecadienoic acid or other oxidized polyunsaturated fatty acids followed by phospholipase D-mediated hydrolysis, the formation of N-(hexanoyl)ethanolamine (HEEA), a head group of HEPE, was confirmed by isotope dilution liquid chromatography/tandem mass spectrometry. Moreover, increasing HEEA was detected in the hydrolysates of oxidized erythrocyte ghosts and low-density lipoprotein with their increasing lipid peroxidation levels. Collectively, these results suggest that the N-hexanoylated product of phospholipid, HEPE, can be generated during lipid peroxidation and may serve as one mechanism for the covalent modification of aminophospholipids in vivo.

Extent of copper LDL oxidation depends on oxidation time and copper/LDL ratio: chemical characterization

The aim of our study was to determine, as a function of [Cu(2+)]/[LDL] ratios (0.5 and 0.05) and of oxidation phases, the extent of LDL oxidation by assessing the lipid and apo B oxidation products. The main results showed that: (i) kinetics of conjugated diene formation presented four phases for Cu(2+)/LDL ratio of 0.5 and two phases for [Cu(2+)]/[LDL] ratio of 0.05; (ii) oxidation product formation (cholesteryl ester and phosphatidylcholine hydroperoxides, apo B carbonyl groups) occurred early in the presence of endogenous antioxidants, under both copper oxidation conditions; (iii) apo B carbonylated fragments appeared when antioxidants were totally consumed at [Cu(2+)]/[LDL] ratio of 0.5; and (iv) antioxidant concentrations were stable, oxysterol formation was negligible, and no carbonylated fragment was detected at [Cu(2+)]/[LDL] ratio of 0.05. Depending on the copper/LDL ratio, oxidized LDL differ greatly in the nature of lipid peroxidation product and the degree of apo B fragmentation.

Structural changes of low density lipoproteins with Cu2+and glucose induced oxidation

The compositional and structural changes of lipids and apolipoproteins during in vitro oxidation of low density lipoprotein (LDL) are investigated in this study by IR spectroscopy. For comparison, LDL samples containing either copper or glucose at physiological or pathological concentrations are considered in order to know the separate affects of these chemical factors on LDL oxidation. The results show that the initial steps of lipid oxidation proceed through hydrogen atom loss from methylene groups, as well as loss of cholesteryl ester molecules, and later a recovering of carbonyl compounds resulting from aldehyde formation that generally occurs in autooxidation processes. Lipid oxidation is induced by copper ions, and glucose enhances metal ion induced LDL oxidation as determined by conjugated diene formation. As to the protein conformational changes, IR spectroscopy reveals for the first time that LDL oxidation involves formation of beta-sheet structures, these being more abundant in LDL samples with pathological concentrations of glucose or copper. Consequently, the LDL structural changes may contribute to the recognition of oxidized LDL particles by scavenger receptors.

Formation of N-(hexanoyl)ethanolamine, a novel phosphatidylethanolamine adduct, during the oxidation of erythrocyte membrane and low-density lipoprotein

The primary amino groups of biomolecules such as aminophospholipids, as well as proteins, are the potential targets of covalent modifications by lipid peroxidation products; however, little attention has been paid to the modification of aminophospholipids such as phosphatidylethanolamine (PE). The purpose of this study was to characterize the formation of a novel modified phospholipid, N-(hexanoyl)phosphatidylethanolamine (HEPE), in the reaction of PE with lipid hydroperoxides using mass spectrometric analyses. Upon reaction of egg PE with 13-hydroperoxyoctadecadienoic acid or other oxidized polyunsaturated fatty acids followed by phospholipase D-mediated hydrolysis, the formation of N-(hexanoyl)ethanolamine (HEEA), a head group of HEPE, was confirmed by isotope dilution liquid chromatography/tandem mass spectrometry. Moreover, increasing HEEA was detected in the hydrolysates of oxidized erythrocyte ghosts and low-density lipoprotein with their increasing lipid peroxidation levels. Collectively, these results suggest that the N-hexanoylated product of phospholipid, HEPE, can be generated during lipid peroxidation and may serve as one mechanism for the covalent modification of aminophospholipids in vivo.

Immunochemical detection of a novel lysine adduct using an antibody to linoleic acid hydroperoxide-modified protein

We have previously prepared the polyclonal antibody to the 13-hydroperoxyoctadecadienoic acid-modified protein (13Ab) (Kato et al. 1997. J. Lipid Res. 38: 1334-1346), however, the epitopes have not yet been structurally identified. In this study, we identified a novel amide-type adduct as one of the major epitopes of 13Ab and characterized the endogenous formation. Upon incubation of the lysine derivative with peroxidized linoleic acid, the formation of N epsilon -(azelayl)lysine (AZL) was confirmed using liquid chromatography-mass spectrometry. The chemically synthesized azelayl protein was significantly recognized by 13Ab. The peroxidation products of different polyunsaturated fatty acids also generated several analogous carboxyalkylamide-type adducts to AZL by the reaction with the lysine derivative, whereas 13Ab specifically recognized AZL, suggesting that the AZL moiety may be one of the major epitopes of 13Ab. The immunoreactive materials of 13Ab were immunohistochemically detected in atherosclerotic lesions from hypercholesterolemic rabbits. More strikingly, the immunoreactivity was significantly enhanced when the sections were treated with alkali or phospholipase A2 for hydrolyzing the ester bonds prior to the staining. These results suggest that the lipid hydroperoxide-derived carboxylic adducts, such as AZL, and their esters linked with phospholipids may be generated in vivo and involved in the pathogenesis of atherosclerosis associated with oxidative stress.

Effect of gangliosides on the copper-induced oxidation of human low-density lipoproteins

The role of gangliosides in the copper-induced oxidative modification of human low-density lipoprotein (LDL) was studied focusing on the early stage of LDL oxidation in which the concentration of conjugated dienes increases only weakly. The changes in the protein and lipid component were followed using fluorescence spectroscopy. The results indicate that binding of gangliosides to LDL causes slower destruction of tryptophan fluorescence and suppresses cross-linking between the reactive groups of the protein and the products of lipid peroxidation. The protective role of gangliosides could be assigned to their interference with the lipid-protein interaction in the LDL particle, which might be important for the maintenance of the native plasma antioxidant status in vivo.

Oxidants and antioxidants affect the expression of glycodelin

Glycodelin is a glycoprotein that has immunosuppressive activity. We have shown that K562 cells, hematopoitic progenitor cells, are capable of synthesizing glycodelin peptide (Gp) and, perhaps, contribute to Gp in tissues. In addition, several reproductive and nonreproductive tissues themselves are capable of synthesis of glycodelin. In this study, we report that lipid peroxides induce the synthesis of Gp. Antioxidants vitamin E and pyrrolidine dithiocarbamate (PDTC) and antioxidizing enzymes catalase and superoxide dismutase (SOD) effectively blocked phorbol myristate acetate- (PMA-) and lyso phosphatidic acid- (LPA-) induced synthesis of Gp. Dioctanoin (a mimic of diacylglycerol) activated Gp synthesis, and an inhibitor of protein kinase C (PKC) downregulated the response. Based on these observations, we postulate that oxidants by way of PKC might potentiate the angiogenic process.

Lemon flavonoid, eriocitrin, suppresses exercise-induced oxidative damage in rat liver

To examine the preventive effect of the lemon flavonoid, eriocitrin (eriodictyol 7-O-rutinoside), on oxidative stress during acute exercise in vivo, levels of N( epsilon )- (hexanoyl)lysine, HEL; o,o-dityrosine, DT; and nitrotyrosine, NT, as oxidative stress markers, were determined by ELISA in livers of trained rats in addition to thiobarbituric acid-reactive substance (TBARS). Eriocitrin administration prior to exercise significantly suppressed the increases in TBARS caused by lipid peroxidation during acute exercise. The contents of HEL, DT, and NT in rat liver increased dramatically by exercise without eriocitrin administration. However, these increases were significantly suppressed by eriocitrin administration before exercise. Moreover, in this study, to clarify whether eriocitrin influences glutathione metabolite system that is considered to be important for a defense against the damage by oxidative stress, the levels of glutathione in rat liver were determined during exercise. The level of reduced glutathione after exercise was maintained by administration of eriocitrin. The increase in the concentration of oxidized glutathione caused by exercise was significantly suppressed by eriocitrin. This result suggested that eriocitrin might play an important role in the control of the change in glutathione redox status in rat liver during exercise. These findings showed that eriocitrin was effective in the prevention of oxidative damages caused by acute exercise-induced oxidative stress.

Oxidized fatty acids promote atherosclerosis only in the presence of dietary cholesterol in low-density lipoprotein receptor knockout mice

Studies suggest that heated oils contribute to the presence of oxidized components in the circulating lipoproteins and to the development of atherosclerosis in animals. We evaluated the effects of 11-13 wk of consumption of a well defined dietary oxidized fatty acid, 13-hydroxylinoleic acid (13-HODE) (8 mg), on atherosclerotic lesion development and plasma cholesterol concentrations in mice fed diets varying in fat and cholesterol contents. LDL receptor knockout mice were used in two feeding studies. In study 1, oxidized fatty acid consumption in association with a high fat diet increased aortic lesion areas by >100% (P < 0.05). Surprisingly, oxidized fatty acid intake also tended to increase plasma total cholesterol (P = 0.12) and LDL cholesterol (P < 0.05) as well as oxidative stress as measured by higher levels of autoantibodies to oxidatively modified proteins (P = 0.008). However, in mice fed a nonpurified diet, oxidized fatty acids were not atherogenic and may even have been beneficial, as indicated by a lower plasma triglyceride (TG) concentration (P < 0.05). In study 2, mice were fed either a high fat, medium fat or low fat diet to evaluate whether the increase in aortic lesions due to oxidized fatty acid consumption in study 1 was a result of the associated higher plasma total and LDL cholesterol concentrations. In study 2, 13-HODE-treated mice in the medium and low fat diet groups but not those fed the high fat diet had larger atherosclerotic lesions (P < 0.05). Additionally, plasma total and LDL cholesterol as well as TG were not affected by HODE treatment. However, the total cholesterol:HDL cholesterol ratio was higher in treated mice (P < 0.05) and HDL cholesterol was lower in HODE-treated mice that were fed the low fat diet (P < 0.05). Our results suggest that, in mice fed cholesterol, oxidized fatty acids may be atherogenic, both in terms of increased oxidative stress (as seen in study 1) and by increasing the atherogenicity of the plasma cholesterol profile.

Regulation and modulation of abnormal immune responses in endometriosis

There is ample evidence demonstrating that endometriosis is accompanied by inflammatory reactions in the peritoneum, resulting in abnormal levels of a variety of cytokines and chemokines in the peritoneal fluid. Among the immunological parameters that have been shown to be altered in the peritoneal cavity of women with endometriosis, an increase in the number of activated nonadherent macrophages that show reduced surface expression of scavenger receptors has been observed. The cause-and-effect relationship between aberrant peritoneal macrophage activity and endometriosis is still unknown. We have demonstrated that steroid hormone receptor agonists and antagonists [e.g., retinoids, antiglucocorticoids, ligands to peroxisome proliferator activated receptors (PPARs)] can regulate macrophage functions in ways that could either suppress or stimulate the growth of ectopic endometrial lesions. Our studies include a number of relevant findings: (1) RU486, acting as an antioxidant, can suppress activation of NFkappaB, a nuclear transcription factor that affects the expression of several inflammatory genes such as those for MCP-1, GM-CSF, CSF-1, and various adhesion molecules; (2) IL-6 secretion from a variety of cell types including endometrial cells is inhibited by retinoic acid; and (3) retinoids and PPARgamma ligands can upregulate the expression of scavenger receptors in cells of the monocyte/macrophage lineage. These observations, combined with the possibility that macrophage activity may play a fundamental role in endometriosis, suggest that pharmacologic manipulation of macrophage function may provide a novel mechanism for treating this disease.

Interactions of nitric oxide and peroxynitrite with low-density lipoprotein

Nitric oxide (*NO) is a free radical species that diffuses and concentrates in the hydrophobic core of low-density lipoprotein (LDL) to serve as a potent inhibitor of lipid oxidation processes. Peroxynitrite (PN), the product of the diffusion-limited reaction between *NO and superoxide (O2*-) represents a relevant mediator of oxidative modifications in LDL. The focus of this review is the analysis of interactions between *NO and PN and its secondary reactions with oxygen radicals on LDL oxidation, which are relevant in the development of the early steps as well as progression of atherosclerosis. We propose that the balance between rates of PN and *NO production, which greatly depends on oxidative stress processes within the vascular wall, will critically determine the final extent of oxidative LDL modifications leading or not to scavenger receptor-mediated LDL uptake and foam cell formation.

Increased myeloperoxidase and lipid peroxide-modified protein in gynecological malignancies

Oxidative stress has been implicated in several diseases, including cancer. Oxidants induce oncogenes and their products associated with cell growth. Even though epidemiological studies implicate oxidants in promoting cancer, there is still a lack of in vivo evidence for the same. In this study, we measured the levels of myeloperoxidase (MPO), an enzyme associated with oxidation and autoantibodies to lipid peroxide-modified protein (LOOH-RSA), in the plasma of subjects with gynecological cancers. The gynecological cancer subjects (n = 201) had higher plasma MPO and LOOH-RSA levels compared with control subjects (n = 60). Immunohistochemical analysis of tissues revealed that immunostaining for MPO and LOOH-RSA was higher in cancer tissues compared with controls. The staining was specific to cell types and not ubiquitously present. Neutrophils, monocytes/macrophages, and natural killer cells have been proposed to play a role in cancer promotion and progression. This study proposes a role for oxidative stress and especially MPO in cancer.

Formation of lipid-protein adducts in low-density lipoprotein by fluxes of peroxynitrite and its inhibition by nitric oxide

Peroxynitrite (PN), the product of the diffusion-limited reaction between nitric oxide (*NO) and superoxide (O*-(2)), represents a relevant mediator of oxidative modifications in low-density lipoprotein (LDL). This work shows for the first time the simultaneous action of low-controlled fluxes of PN and *NO on LDL oxidation in terms of lipid and protein modifications as well as oxidized lipid-protein adduct formation. Fluxes of PN (e.g., 1 microM min(-1)) initiated lipid oxidation in LDL as measured by conjugated dienes and cholesteryl ester hydroperoxides formation. Oxidized-LDL exhibited a characteristic fluorescent emission spectra (lambda(exc) = 365 nm, lambda(max) = 417 nm) in parallel with changes in both the free amino groups content and the relative electrophoretic mobility of the particle. Physiologically relevant fluxes of *NO (80-300 nM min(-1)) potently inhibited these PN-dependent oxidative processes. These results are consistent with PN-induced adduct formation between lipid oxidation products and free amino groups of LDL in a process prevented by the simultaneous presence of *NO. The balance between rates of PN and *NO production in the vascular wall will critically determine the final extent of LDL oxidative modifications leading or not to scavenger receptor-mediated LDL uptake and foam cell formation.

Regulation of colony stimulating factor-1 (CSF-1) in endometrial cells: glucocorticoids and oxidative stress regulate the expression of CSF-1 and its receptor c-fms in endometrial cells

OBJECTIVE

To evaluate the regulation and expression of CSF-1 and its receptor c-fms in endometrial cells.

DESIGN

In vitro study.

SETTING

Research and teaching institution.

PATIENT(S)

None.

INTERVENTION(S)

In vitro experimental study.

MAIN OUTCOME MEASURE(S)

The effect of glucocorticoid and oxidative stress on the expression of CSF-1 and c-fms in endometrial cells.

RESULT(S)

Cultured nonmalignant EM42 cells not only express CSF-1 and c-fms but are also capable of responding to exogenous CSF-1. We have also seen that glucocorticoids can regulate the expression of CSF-1/c-fms in endometrial cells. Furthermore, this study shows that oxidative stress plays a significant role in the induction of CSF-1 and its receptor c-fms.

CONCLUSION(S)

The results suggest that CSF-1 may promote the growth of nonmalignant endometrial cells in both an autocrine and paracrine manner and that endometrial cells under oxidative stress induce CSF-1 and c-fms.

Preparation of a monoclonal antibody to N(epsilon)-(Hexanonyl)lysine: application to the evaluation of protective effects of flavonoid supplementation against exercise-induced oxidative stress in rat skeletal muscle

The monoclonal antibody to N(epsilon)-(hexanonyl)lysine (HEL), a novel adduct formed by the reaction of linoleic acid hydroperoxide and lysine, has been prepared and characterized. The obtained antibody specifically recognized the HEL moiety. Using the monoclonal antibody, we evaluated the protective effects of feeding eriocitrin, which is one of flavonoids in lemon fruit, on oxidative modification induced by exercise in rats. The supplementation of eriocitrin significantly suppressed the increase in HEL in the skeletal muscle by exercise. The result suggests that the determination of HEL may be a good method for evaluation of the protective effect of beneficial food factors against oxidative stress.